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Volume 91-B, Issue SUPP_II May 2009

M Bhattacharyya B Gerber

Objectives: to illustrate our clinical experience with the computer-integrated instrumentation system in knee arthroplasty.

Method: From August 2003 to April 2006, 71 patients with knee osteoarthritis underwent 71 primary TKR operations by the same surgical team. All these operations were performed with the aid of the CT-free kinematic navigation system, Results, including operation time, radiographic alignment of the prosthesis and complications were analysed.

Results: The average wound length was 11.2 centimeters. Patients in the kinematic navigation group achieved accurate alignment in the coronal plane in terms of postoperative mechanical axis (1.89 +/− 0.63 degrees. one perioperative fractures and mediolateral flexion laxity occurred both of which were attributed to patient factors as opposed to operation procedures. No major complications such as infection or pulmonary embolism occurred in this cohort.

Conclusions: The OrthoPilot system facilitates proper alignment of the component in knee arthroplasty. We found the OrthoPilot system is reliable and reproducible. The preliminary results justify continuing the use of this technologyto help the patients to provide the best possible care. Use of a kinematic navigation system in TKR is easy to use, and requires an additional operation time.

A. Desai C. Bangalore A. K. Choudhary

Aim and objectives of the study: To assess the true incidence and reasons for readmission after fracture neck of femur treatment and its effect on Trust star rating.

Introduction: Star ratings (zero to three) show how well a Trust is performing and is awarded against a set of performance indicators (Patient Focus, Capacity and Capability Focus and Clinical Focus) as laid by CHAI

These indicators cover the standards and outcomes of treatment given.

CHAI reports 9% readmission as an emergency within 28 days, and assumes that a proportion of the observed readmissions are potentially avoidable.

Materials and Methods: An audit done by the managers found 15 (19%) cases of readmission of fracture neck of femur during April to October 2004. We did Re audit by reviewing the exact cause for readmissions in all the cases.

Results: Out of 15 cases identified by the managers only 4 (5.19%) were true readmission, which is below the national average.8 readmissions were for medical reasons, 3 for social reasons and rest 4 were related to fracture complications like infection.

Conclusion: Star ratings (zero to three) reflect Trust performance and are awarded against a set of performance indicators, which cover the standards, and outcomes of treatment given (Patient Focus, Capacity and Capability Focus and Clinical Focus) as laid by CHAI.

We conclude that audit should be done as a team-work involving all responsible health care professionals and proper uniform coding system needs to be followed to obtain correct results.

M Bhattacharyya B Gerber

Purpose: The current clinical Study was compared with historical control in terms of level of pain perception, blood loss and post-operative mobility in patients undergoing arthroplasty of the hip with computer navigation. A secondary objective was to investigate the level of patient satisfaction with the procedure.

Methods: The prospective study was conducted over a 24 month period. 30 Patients were sequentially operated and contralateral hip operated by different surgeons previously compared as control group. Delayed mobility was observed in 6% of patients with managed with computer navigation only. 2 patients had dislocation in early post-operative period, which was relocated Significantly less patients managed with the computer assisted hip arthroplasty complained of pain around the wound site [p< .01]after 48 hours of index surgery. Mean Blood loss was less [725ml Vs 1230ml] and mean length of skin incision [10.8cm Vs 17.5 cm] is lesser than the conventional arthroplasty.

Patient satisfaction was higher in the navigated group and 86% of patients were able to fully mobilize within 72 hours of the index operation.

Conclusion: Soft tissue trauma during surgery is an important cause of post-operative morbidity. Surgical exposure and malposition of the acetabular cup may cause delayed post-operative mobility after conventional hip arthroplasty

Computer aided hip arthroplasty may influence postoperative outcome in otherwise uncomplicated surgery. Although the study was limited by non randomization and other variables, initial results are encouraging.

Sameh Ansara Sab. Chokkalingam S. Geeranavar

Introduction: Idiopathic Adhesive capsulitis [IAC] of the shoulder is a self limited condition that can cause significant morbidity. Most patients (90%) respond to conservative management and those who fails (10%) undergo manipulation under anaesthesia (MUA) Patients who are refractory to both treatments, benefits from arthroscopic capsular release.

Aim: To assess the efficacy of arthroscopic capsular release in patients with IAC refractory to physiotherapy and MUA. Also to compare the clinical outcome between arthroscopic capsular release and MUA.

Materials and methods: We studied 59 patients with IAC, divided into 2 groups. Group A [36patients] had MUA and Group B [23 patients] underwent arthroscopic capsular release. The mean age was (54years).

The mean follow up was 21 and 9 months for group A and B respectively.

Results: We assessed our results according to three parameters:

Final outcome using the Constant and Murley score. The improvement in the score averaged 42 and 47 points in group A and B respectively

Early Post operative pain using visual analogue score (VAS) average of 6 and 3 in group A and B respectively

Overall patient satisfaction: 81% in group A and 89% in group B.


Patients with IAC who fails to respond physiotherapy and MUA do well after arthroscopic capsular release with little operative morbidity.

Complete normal functional outcome of shoulder is not a prerequisite for patient satisfaction.

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Raj Chari Adil Aweid Mark Bloomfield

Purpose: To find the incidence of Periprosthitic fracture following Birmingham Hip Resurfacing over the age of 65 yrs – in Ashford & St. Peters Hospitals.

Method: We have done an audit to study the total number of patients who had Femoral neck fractures following Birmingham Hip Resurfacing, comparing them with the incidence of Femoral neck fracture in the age group of 65 yrs & above, from the period of March 2000 to January 2006 in Ashford & St. Peters Hospitals (NHS & Private)

Between March 2000 and January 2006, 327 Birmingham hips were inserted by 8 surgeons. Fracture of the neck of the femur occurred in 5 patients, an incidence of 1.53%.


1 Intra op fracture & 4 post op fractures.

Out of the total number of patients, 131 were above the age of 65years, with mean age of 68.80 years & a range of 65–77 years.

No Femoral neck fractures were found in this age group.

Conclusion: Incidence of Femoral neck fracture is NIL in the age group of 65 yrs & above compared to 1.53% over all.

M Hossain AK Sinha H Akhtar J Andrew

Purpose: To investigate the value of various clinical signs to identify occult hip fracture.

Methodology: MRI register was searched to identify all patients who had MRI scan between July 2000–June 2006 for suspected occult hip fracture. 64 patients were identified. 33 patients had occult proximal femoral fractures. 27 patients had no fracture.

Results: 19 patients with fracture were not independently mobile compared to 6 patients without fracture. 7 patients with fracture and 2 patients without fracture were able to weight bear. 13 patients with fracture and 10 patients without fracture had unrestricted straight leg raise ability. 7 patients with fracture and 16 patients without fracture had no pain on axial loading. Fisher exact and chi square analysis was performed; with Bonferroni correction for multiple comparisons (10 tests) p< 0.005 was deemed significant. Pain on axial loading of limb and pre-fracture patient mobility were associated with fracture (p< 0.005). Both factors had positive predictive value = 0.76 and post-test probability of disease given a negative test = .30. Predictive values remained the same when both factors were considered together.

Discussion: These data indicate that although patients who were independently mobile before the fall and who do not have pain on axial compression of the limb are less likely to have a fracture, these signs alone or in combination will not exclude a fracture. It is essential to perform MRI scanning of patients with severe hip pain but normal x rays after fall as it does not seem possible to clinically exclude fracture.

R. Kakwani KHA Wahab

Introduction: A retrospective audit to evaluate the results of Austin Moore hemiarthroplasty conversion to Total hip arthroplasty for suspected aseptic loosening.

Materials and Methods: A consecutive cohort of patients who had conversion of Austin-Moore hemiarthroplasty to Total hip arthroplasty performed at our district general hospital between August 2000 and May 2006 were included in the study.

The total of 41 patients were divided into two groups depending on the duration between the primary hemiarthroplasty procedure and its revision to total hip arthroplasty – (1) Less than one year (16 patients) and (2) More than one year (25 patients).

The data collected included: age, sex, classification of the fracture, date of primary operation, surgical approach, inflammatory markers, indication and date of revision to total hip arthroplasty, and the final outcome.

Results: The rate of infection after the revision to total hip arthroplasty was found to be 25% (4/16 patients) in patients who underwent the revision operation within 1 year after the primary operation, whereas the infection rate was 8% (2/25 patients) for those who had the revision operation more than a year after the primary operation. The difference in infection rates between the two groups was found to be statistically significant despite the small numbers.

Discussion: The patients who have early loosening of the Austin-Moore hemiarthroplasty within the 1 year of the primary procedure should raise a suspicion of occult infection. Despite near normal inflammatory markers, a two-staged conversion to total hip arthroplasty should be seriously considered.

SG Shalaby E Shenouda K Rizkalla G Morgan A Amini SPF Hughes HV Crock

Introduction: The purpose of the study was to evaluate the outcome of multiple spinal operations by an expert spinal surgeon HV Crock.

Materials and Methods: A retrospective review of 169 patients who had multiple spinal surgery including spinal Fusion and spinal decompression was undertaken. A special Questionnaire form was designed and sent to each patient to answer with an appointment for the patient to be seen and assessed in the spinal assessment clinic where data from the questionnaire, clinical notes and thorough clinical examinations were recorded in a spinal data base which covered the following sections:

Patients Symptoms

Treatment received

Spinal Operations

Body Diagram for shading the site of pain

Final outcome

Patient Satisfaction


– 76 patients 66% of the patients who replied “were satisfied” with the surgery.

– 38 patients 33% of the patients who replied were not satisfied.

– 58 patients did not reply as they were not interviewed.

There were no significant post-operative neurogenic complications, such as cauada equina syndrome or severe leg weakness interfering with standing and walking retirement. There was always a temporary relief followed by deterioration of symptoms after a period ranging between 1–2 years.

Conclusions: Overall, patients with failed back syndrome need to be evaluated and treated in a multidisciplinary setting, where a group of Health Care Professionals from various fields, such as Physiotherapy, Pain Management and Clinical Psychologist work together, towards the common goal for the benefit of the patient

A S Desai A Deeb C. Bangalore A K Choudhary

Materials & Methods: A retrospective study. 25 cases of fracture Calcaneum during April 2001–2004 were reviewed for their clinical outcome.

Aim of the study: To assess the clinical and functional outcome of the Management of Intra and Extra articular Calcaneal fractures in district general hospital.

Results: 22 male and 3 female. Intraarticular fractures 15 (60%)of which 10 were displaced and 5 undisplaced.

Extraarticular were 10 (40%) of which displaced and undisplaced were 5 each. Fall from height was seen in 20 (80%)patients. Associated injuries was seen in 10(40%) patients of which 8(32%) of them had fracture spine. All the cases of intaarticular fractures had C.T. scan.

5 cases had MUA and pinning for the extraarticular fracture.

8(32%) displaced intraarticular fractures underwent ORIF.

2((8%) intraarticular displaced fractures were treated conservatively.

The average follow-up one-year.

The final outcome assessed clinical and radiologically.

2 cases of infection, 4 cases of stiffness, 2 cases of deformity seen.1 case had parasthesia.

The final outcome all the fractures treated conservatively were good. Fractures underwent ORIF had better outcome and more complication rate as compared to conservative treatment.

Conclusion: Commonest mode of injury is fall from height and associated injury incidence is usually high.

Even the undisplaced intraarticular fractures of calcaneum do develop residual stiffness and difficulty in walking on uneven ground.

Displaced fractures needs fixation for better results and facilitation for secondary operations.

Wound infection, stiffness and deformity are known complications.

In this small audit all three group did develop stiffness and we recommend a bigger, independent audit.

Anand Arya Sunil Garg Joydeep Sinha

Complex proximal humerus fractures have been described as the unsolved fracture. Review of literature shows a variety of treatment methods and results. We present the results of a prospective study of 47 complex proximal humerus fractures treated by PHILOS (Proximal Humeral Internal Locking System) plate. The aim of this study was to assess the effectiveness of the PHILOS plate in the surgical treatment of Neer’s type 3 & 4 fractures.

We operated upon 47 patients (mean age 56yrs) between March 2002 and January 2006 for fixation of 3 part (28 patients) and 4 part (19 patients) fractures at a level 1 trauma centre. An independent observer reviewed patients at 6 monthly intervals for clinical and radiological assessment. Outcome measures included DASH and Constant scores.

42 patients were available for follow up, which ranged from 12–66 (average 24.4) months. Recovery of movements, and relief in pain was satisfactory in most of the patients, but the strength of shoulder did not recover fully in any patient. There were two failures in our series, one due to breakage of plate and another due to non-union; both treated successfully by revision. 4 patients (8%) had radiological signs of avascular necrosis of humeral head but only 2 of them were symptomatic requiring further treatment. Pain due to impingement was noted in several patients leading to removal of plate (6 patients) and subacromial decompression (3 patients). We encountered the problem of cold welding and distortion of screw heads, while removing the plate. The broken plate was subjected to biomechanical and metallurgical analysis, which revealed that the plate is inherently weak at the site of failure.

We concluded that in spite of the above-mentioned complications, the PHILOS plate is a reliable implant to fix 3 and 4 part proximal humeral fractures. We were particularly impressed with the satisfactory results of fixation in 4 part fractures. However, we are not convinced about its strength. The plate may cause impingement in some patients necessitating its removal later on, which itself may not be easy.

Level of Evidence: Therapeutic study, level IV (case series).

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S Wadawadigi B Banerjee

Purpose of the study: To ascertain, the Post-operative Joint Infection rates in the Department during 2004.

Methods used and the results: Details of 607 patients were collected. Females were 379(62%) whereas males were 228(38%). Less than 65 years were 133(22%), between 66 and 80 years were 319(53%) and above 80s figure was 155(26%). Total of 197 Primary Hip Arthroplasties (THR) and 190 Knee Arthroplasties (TKR) had been performed. Hip Hemiarthroplasties totalled 137. All the demographic indicators were looked in detail for gender and age range distribution. Revision THRs were 66 whereas 17 were Revision TKRs.

For the purpose of this study, the Revision Arthroplasties were excluded.

Amongst Total Joint Arthroplasties, though 10 patients out of 387 had provided positive results for STAA (Staph. Aureus) from swab specimens, none of the patients developed deep infection. But out of 8, who showed MRSA growth from wound swabs, one patient developed deep infection and needed conversion to Girdlestone procedure. Thus the positive results for wound specimens were 18(4.65%), while the re-operation rate was 1(0.26%).

Conclusion: It is interesting to note that MRSA was prevalent in above 80s while STAA was more common in under 80s. Majority of MRSA positive results were after 30 days while that for the STAA it was before 30 days post-operatively. Of the 18 ‘infected’ cases; Consultants and SAS surgeons had performed 9 cases each.

Amongst 137 Hip Hemiarthroplasties, 25 showed positive growths, 7 for STAA and 18 for MRSA. None needed re-operation.

Interesting revelations on misconceptions are revealed!

Sunil Garg Sunil Bajaj R. Wetherall

50 consecutive cases of Scaphoid non-union were treated by open reduction and internal fixation. Average age of non-union was 2.8 yrs ranging fron 6 months to 6 years. Most common approach used was volar. Herbert screw was used to fix 48 non-unions while K wires were used in 2 cases. Bone graft was harvested from patient’s iliac crest and was used in nearly all cases. Wrist was immobilised in a plaster for an average duration of 12 weeks post operatively. All the cases were done by a single surgeon and the cases were recorded by an independent observer.

The average follow up was 2 years ranging from 1 year to 6 years. Radiographic union was achieved in 45(80%) cases. Failure of union was seen in 10 cases out of which 5 were proximal pole fractures of which 2 went into avascular necrosis. Denervation of wrist, proximal row carpectomy and four corner fusion was used in 5 cases to salvage the wrist.

This modest study carried out at a district general hospital of South East England suggests that scaphoid bone continues to be a challenge for general orthopaedic surgeon as some of these fractures are missed initially. Open reduction and internal fixation of Scaphoid non-union continues to give a predictable outcome.

KP Iyengar JB Nadkarni

Purpose of study: To evaluate the results Biomet® Retrograde Closed Intramedullary nailing in the treatment of femoral shaft fractures and femoral fractures below a pre-existing hip implant in elderly patients.

Patients and Methods: 25 patients were treated with closed Biomet® Retrograde Femoral Nail between February 2003 and January 2004. Eight of these had occurred below a previous hip implant. There were 19 female patients and 6 male with a mean age of 72 years. Mechanism of injury, demographics and AO fracture pattern were recorded. Pre-fracture mobility, operative details, post-operative management, complications if any, was noted. Time to clinical and radiological union, outcome using the Wilde modification of the Neer scoring system after mean follow-up of 1 year was evaluated.

Results: 2 patients were lost to follow-up and 4 patients died following unrelated medical conditions. 19 patients were available for final review. Most patients had an excellent outcome with a mean clinical and radiological union at around 15.8 weeks (range 11–20 weeks). 4 patients had backing out of a distal locking screw, which were removed. There were no implant failures. 15/19 patients achieved their pre-injury mobility status.

Conclusion: We conclude that displaced fractures of the femur and those below a hip implant can be effectively managed with closed Biomet® Retrograde Femoral intramedullary nail. Surgery is less traumatic, safe, and allows early mobilization, resulting in a good functional recovery.

S A Ali J Ahmed N Siddiqi V Mullins K Rahmani S O Shafqat

Background: Over many years our understanding of fracture patterns and management has evolved. One of the biggest steps was the adoption of the principles of fracture fixation as described by the Arbitsgemeinschaft fur Osteosynthesefragen (AO). The application of this philosophy has allowed us to optimise fracture management and improve outcome.

In our unit we noted a number of complications resulting from suboptimal fracture fixations of ankles some of which required revision. It was decided to review fracture fixation of ankles in the unit to see whether the basic principles of fixation was being followed in our DGH.

Aim: To evaluate whether the AO principles of fixation for ankle fractures are being followed in our local unit.

Patients and Methods: 52 consecutive patients over a period of 1 year from August 2005 to August 2006 with bi malleolar and isolated medial malleolar ankle fractures, requiring surgery, had their case notes and pre operative x rays reviewed retrospectively looking at fracture patterns according to the AO and Weber classification. Post operative x rays where reviewed to see if the principles of facture fixation had been appropriately followed.

Results: Of the 52 patients evaluated 26 were Weber type B fractures, 20 were type C and 6 were isolated medial malleolar fracture. Nine of the type B and three of type C (23% of the total number) underwent fixation not in accordance with AO principles.

In every case the fibula fixation did not include a cortical lag screw.

Discussion/Conclusions: Although none of the 12 described had to undergo revision, their management was far from optimum.

By ensuring that operating surgeons have the appropriate training and experience in basic fracture fixation before being allowed to undertake such procedures, our unit hopes to show an improvement on these figures by the time this audit is repeated.

HPS Gakhar KSRK Prasad SS Gill MS Dhillon

As management of open tibial fractures remains controversial, we hypothesised that unreamed intramedullary nail offers inherent advantages of a nail as well as external fixation, while limiting the morbidity of external fixation.

We undertook a prospective randomised study to compare management of open tibial fractures with external fixator or intramedullary nail until fracture union or failure. Our study included 30 consecutive open tibial fractures (Gustilo I, II & IIIA) between 4 cm distal to knee and 4 cm proximal to ankle in skeletally mature adults, who presented to a level-1 trauma centre. Alternate patients were treated by external fixation or unreamed nail i.e. 15 in each group. Standard protocol for debridement and fixation was followed. External fixators were removed at 6 weeks. All cases were followed until fracture union, the main outcome measurement.

26 (87%) males and 4 (13%) females; age 20–60 years (Mean 33.8). All fractures in both groups united. Time to union averaged 7.9 months for both groups. Incidence of wound problems, infection, hardware failure and delayed union were comparable. However, there was higher incidence of angular deformities and stiffness of knee and ankle in external fixation group, although not statistically significant.

We found no statistically significant difference between unreamed intramedullary nailing and external fixation for the management of open tibial diaphyseal fractures. Ease of weight bearing as well as absence of angular deformities and joint stiffness were distinct advantages in the nailing group. Therefore we recommend unreamed nail for Gustilo I, II & IIIA open tibial fractures.

W.E.A Hekal A.S. Desai J.R. Panezai

We present a case of osteolytic lesion in Gruen Zone 2, 3 in a six-month post-operative cemented THR initially diagnosed as early loosening-?Septic. Investigations and biopsy revealed metastatic renal cell carcinoma.

A 79 year old gentleman had a Left cemented THR and was symptom free post-operative. Six months later he had pain in the left groin and thigh. Examination revealed painless hip movements. X-ray showed lytic area in zone 2 and 3. ESR -90 mm and CRP – 50 mg/dl. Hip aspiration excluded sepsis. Bone scan showed increased uptake of left femoral shaft, right scapula and L1 vertebra. Bone chemistry, renal & liver Assay and tumour markers were normal.

Open biopsy showed erosion of lateral cortex, with friable soft tissue mass with profuse bleeding. Histopathological report showed classical clear cell renal cell carcinoma. CT abdomen and chest revealed multiple nodules in lung fields, multiple nodules in liver, mass in both kidneys consistent with Renal cell carcinoma, multiple skeletal lytic lesions.

Patient was referred to oncologist for palliative treatment

DISCUSSION: In case of osteolytic erosive lesions at cement bone interface, the possibility of metastatic lesions should be considered.

In old age groups Biopsy is recommended to exclude malignancy after exclusion of septic and aseptic loosening and abdominal ultrasound to exclude primaries.

CP Armitstead A Wilkin S Ansara W Walters JC Clothier

Introduction: The use of an Aircast walking boot following operative fixation of ankle fractures has been shown to significantly improve early patient comfort, post-fracture swelling and time to full rehabilitation. However, the practical implications and in particular the financial impact of this orthosis has not been assessed. The current study, therefore, aims to determine whether use of the removable splint following operative fixation provides an economically viable alternative to the standard below knee cast.

Materials and methods: Between May 2006 and January 2007 those patients who underwent operative ankle fixation and who were treated postoperatively with the use of an Aircast walker were identified. A group of age-matched controls were used for comparison. Demographic details and postoperative outcomes including postoperative stay were obtained from the hospital notes and computer records.

Results: 12 patients were treated with an Aircast boot during the study period. The mean age of the study group was 43.6 years compared to 43.3 years in the control group. Operative fixation was carried out within 0.83 days and 0.92 days respectively. Patients in the Aircast group were discharged within a mean period of 2.92 days following surgery compared to 3.58 days in the control group.

Conclusions: The current study demonstrates that the use of an Aircast walker boot in the postoperative period is clinically comparable to the standard below knee cast. In particular, the orthosis also enables patients to be discharged home earlier, which has positive implications both for patient recovery and the overall cost of treatment.

M Bhattacharyya A Bashir B Gerber

Increased emphasis has been placed on hospital length of stay and discharge planning after total joint arthroplasty. The purpose of this study was to identify patient characteristics and assistance of surgical innovation could reduce length of stay of an inpatient after TJA.

Method: We analysed demographic and Clinical data 92 consecutive patients who underwent primary TKR with computer assisted surgery [n=46] and compare with another group operated with manual technique[n=46].

Result: Average length of stay: 8.87days (+/− 5.16 SD) in the navigation group and 7.59days (+/− 3.82 SD) in the manual group. Older age, higher American Society of Anesthesiologists class, social circumstances, and female sex were all associated with a higher likelihood of discharge to an ECF.

Conclusion: No Significant differences in length of stay patterns were found in this cohort with respect to discharge disposition at home after knee joint replacement. We believe to reduce length of stay while maintaining quality of care, early discharge home with integrated community services or home care nursing and physiotherapy should be more important than surgical innovation in the NHS in U.K

R. Kakwani D. Chakrabarti A. Das

Aim: To assess the implications of implementation of the NICE Guidelines for indication for CT scan in head injury patients.

Methods and Materials: A retrospective audit of the patients attending our district general hospital with head injuries over a period of one year from October 2004 till Sept 2005. A total of 3150 patients attending the A & E during the study period were diagnosed to have head injuries. The study involved review of the case notes and radiology results of the 135 patients requiring inpatient treatment for head injury. During this tenure the CT scan was requested depending of the clinical judgement of the attending physician.

Results: Rigid compliance with the NICE Guidelines during the study tenure would have entailed an additional workload of 36 patients requiring a CT scan, of which 28 patients justified the scan during out of hours period.

One elderly patient with a fatal intracerebral bleed was found to have justified an early CT scan on the criteria of more than one vomiting episode and a history of unconsiousness.

Discussion: The NICE Guidelines were found to be implemented in most cases admitted during working hours. A reluctance to perform CT scan was encountered during out of hours. A strict compliance with the guidelines would entail on average one additional CT scan every fortnight during the ‘out of hours’ period. Implementation of NICE Guidelines was found to tighten the net (justify CT scan) in order not to miss subtle early signs of potentially fatal head injuries.

A Arya S Garg J Sinha

Four part (Neer’s) proximal humeral fractures if treated by fixation are prone to develop avascular necrosis of humeral head; requiring further treatment and possible reoperation. This has led to the popularity of hemiarthroplasty as the primary treatment in these fractures. Since the availability of contoured locking compression plate (PHILOS) in our unit, we have treated most of the 4 part proximal humeral fractures by internal fixation. The aim of this study was to assess the usefulness of the PHILOS plate in the treatment of these fractures.

We prospectively reviewed 21 patients (mean age 57 yrs) operated between March 2002 and January 2006 at a level 1 trauma centre, using 3/5 hole PHILOS plate for fixation. An independent observer reviewed them postoperatively at 6 monthly intervals for clinical and radiological assessment. Outcome measures included DASH and Constant score. A SPECT/bone scan was done in appropriate cases.

18 patients were available for follow up, which ranged from 12–66 (average 24.4) months. Recovery of movements and relief in pain was satisfactory in most of the patients with mean Constant score of 63 points (range 37 to 95) and DASH score of 20 points (range 15–78) at last follow up.. We encountered a few complications including non-union (1); implant breakage (1) and impingement (4). Only one patient in our series required hemiarthroplasty; out of two who developed symptomatic avascular necrosis. Patient satisfaction was high in spite of moderate Constant score. Removal of PHILOS plate was difficult in some cases due to problem of cold welding and distortion of screw heads. The broken plate was subjected to biomechanical and metallurgical analysis, which revealed that the plate is inherently weak at the site of failure.

Our series is comparatively small to draw any firm conclusions but we feel that with the availability of better implants, there is a case to consider the fixation rather than arthroplasty as the primary treatment of 4 part proximal humeral fractures.

Level of evidence: Therapeutic study – Level IV (prospective case series)

W. Hekal A.S. Desai M.J. Farhan

Aim of the study: To assess the results of the uncemented oblong shaped Bofor cup in acetabular revision.

Methods & materials: A prospective study from January 2001 to July 2006.15 cases of acetabular revision in 14 patients is studied. Paprosky classification for the acetabular defects is used. Final outcome assessed clinically and radiologically. Both Harris hip and Oxford hip functional scoring is used to assess the patients. None of the cases are lost in follow up.

Results: The average follow-up was 36 months (range 8–52 months). All the cases were of aseptic loosening. 1case of type 2a, 6 cases of type 2b, 5 cases of type 2c, 3cases of type 3 defect and 4 cases with medial wall defect were noted. Stem was revised in 8 cases.

In 4 cases auto graft from iliac crest was used. allograft was not used in any cases. In 12 cases 15 degree hooded insert was used. Average HHS improved from 30 points (range 20–38) to 84 points (range 70–90). Average OHS improved from 24 points (range 18–40) to 82 points (range 74–92). There were no cases of dislocation& infection.1 patient had sciatic nerve neuropraxia.1 case of severe Ankylosing spondylitis failed which was revised.

Conclusion: Assemytical shape and design of the Boforcup makes it an useful cup for segmental and cavitatory acetabular defects. Pre operative classification of acetabular defects is inconsistent and unreliable. Allograft usage is not essential for these defects.

R.G. Kakwani A Das A Sinha G. Krishnamurthy

Aim: To assess the implications of nerve conduction study for carpal tunnel syndrome.

Methods and Materials: A retrospective audit of the patients who underwent carpal tunnel release at the district general hospital from July 2000 till June 2005. Due to the un-availability of facility for nerve conduction study at our district general hospital, the patients had to be referred to other hospitals in the region for the same. A total of 263 carpal tunnel releases were performed during the study period in 206 patients (57 were bilateral). 61 patients were males and 145 were females.

Results: Of the classical presentation group, the nerve conduction study was requested in 76 of the 172 patients while in the atypical presentation group 53 of the 91 patients had a nerve conduction study prior to the operative treatment. The intra-operative findings of thickened flexor retinaculum and thinned median nerve were statistically similar in the 2 groups: Nerve conduction not performed and Nerve conduction study performed.

Discussion: The average duration between the first consultation and the operative treatment was 72 days in the patients who did not undergo the nerve conduction study, whereas the average duration between the first clinic appointment and the operative treatment for the patients who had the nerve conduction study was 180.5 days. The request for nerve conduction study in cases with classical presentation leads to an average 108.5 days delay in the final management of the patient’s problem. It also causes a significant loss of time and finances.

P.M. Guyver M.J.H. McCarthy N.P.M. Jain J. Keenan

The PFNA device was developed to address problems of rotational instability in proximal femoral fractures whilst simultaneously employing a single femoral neck element. The PFNA makes use of a helical blade that compresses rather than destroys osteopaenic cancellous bone.

All subtrochanteric fractures admitted to the department were treated with the PFNA (AO 31A3). Demographic and clinical data during admission was recorded and formal post-operative X-Rays performed.

Outcome assessment consisted of a 4 month follow-up appointment with clinical and radiological assessments, VAS, SF36, Jensen Social Function Score and Parker Mobility Score.

From April to December 2006, 46 patients were included in the study. 4 month follow up has been completed in 17 of 23 patients. The average age was 78. 11 short and 7 long nails were inserted. Four patients required open reduction and internal fixation. There were no significant intra-operative or immediate postoperative complications. 1 short nail fractured through the site of the distal locking bolt during the follow up period and required revision.

At follow up, 5 patients had tenderness over the greater trochanter and 2 had leg length discrepancy. None had malrotation. Only 2 patients regained their pre-operative mobility status. The mobility and social function scores were significantly reduced at follow up compared to pre-operative status (p=0.003 and p=0.001 respectively). All domains of SF36 were low compared to normative data. The mean VAS was 3/10.

All fractures united and there was no migration, lysis around or cut out of the helical blade. In total, 25 distal locking bolts were utilised. Four of these had migrated or become loose.

Patients with subtrochanteric fractures do not return to pre-fracture function at 4 months post injury. The PFNA appears to work well although there may be concern about bone hold of the distal locking bolts.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

P. Baker R. Nanda P. Proctor W. Eardley B. Hanusch I. McMurtry J. Hovenden

MRSA infections are a current concern in the elderly orthopaedic patient, with colonisation rates of between 417% reported in these patient groups. In our institution there has been concern regarding MRSA surgical site infection and cross contamination of elective and emergency patients. This prompted the unit to consider a screening programme to identify MRSA carriers. We undertook the following project to assess the feasibility and effectiveness of implementing such a screening programme.

The aim was to to ascertain the incidence of colonisation with MRSA, rate of wound infection and associated risk factors in patients admitted with a fractured proximal femur.

This was a prospective, blinded case series of 100 consecutive patients admitted to the trauma ward with a fractured proximal femur. Three swabs (axilla, nasal and perineum) were taken within 24 hours of admission. Data from each patient was collated and each patient was followed until discharge to assess for surgical site infection.

The age range was 60–97 years. 26% were admitted from institutional care. Four patients were colonised with MRSA on admission. An association was seen between patients colonised on admission and long term or recent residence in institutional care. One of these patients went on to develop colonisation of the surgical wound however this did not lead to surgical site infection and the patient was successfully treated with MRSA eradication therapy only. In these 4 patients all wounds healed satisfactorily with no evidence of infection.

While MRSA continues to be a growing concern in the press we found that rates of colonisation and subsequent infection were not high. There were no documented cases of MRSA wound infection in colonised individuals. Given the cost to detect these low levels of colonisation we do not feel that a screening regime would be cost effective or justified.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

J.C. Talbot G. Cox M. Townend M. Langham P.J. Parker

Femoral neck stress fractures (FNSF) are uncommon, representing around 5% of all stress fractures. In military personnel, FNSF represents one of the severest complications of military training, which can result in medical discharge. Clinical examination findings are frequently non-specific and plain radiography may be inconclusive leading to missed or late diagnosis of FNSF. This paper highlights the significance of FNSF’s in military personnel and alerts physicians to the potential diagnosis. We identified all military recruits, aged 17 to 26, who attended the Infantry Training Centre (Catterick, UK), over a four-year period from the 1st July 2002 to 30th June 2006, who suffered a FNSF. The medical records, plain radiographs, bone scans and MRI’s of the recruits were retrospectively reviewed. Of 250 stress fractures, 20 were of the femoral neck; representing 8% of all stress fractures and an overall FNSF rate of 12 in 10,000 military recruits. FNSF’s were most prevalent amongst Parachute Regiment recruits (1 in 250, p< 0.05). Onset of symptoms was most commonly between 13–16 weeks from the start of training. The majority (17/20, 85%) of FNSF’s were undisplaced, these were all treated conservatively. Three FNSF’s were displaced on presentation and were treated surgically. Overall, the medical discharge rate was 40% (8/20). FNSF’s are uncommon and the diagnosis remains a challenge to clinicians and requires a high index of suspicion in young athletic individuals. In such individuals early referral for MRI is recommended, to aid prompt diagnosis and treatment, to prevent serious sequelae.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

P.J. Kiely K.S. Lam J. Kendrew A. Scheuler L. Breakwell R. Kerslake J.K. Webb

High velocity vertical aircraft ejection seat systems are credited with aircrew survival of 80–95% in modern times. Use of these systems is associated with exposure of the aircrew to vertical acceleeration forces in the order of 15–25G. The rate of application of these forces maybe upto 250G per sceond. Upto 85% of crew ejecting suffer skeletal injury and vertebral fracture is relatively common (20–30%) when diagnosed by plain radiograph. The incidence of subtle spinal injury may not be as apparent.

A prospective case series, admitted to QMC Nottingham, from 1996 to 2006 was evaluated. During this interval 26 ejectees from 20 aircraft were admitted to the spinal studies unit for comprehensive examination, evaluation and management. The investigations included radiographs of the whole spine and magnetic resonance Imaging (incorporating T1, T2 weighted and STIR saggital sequences). All ejections occurred within the ejection envelope and occurred at an altitude under 2000 feet (mean 460 feet) and at an airspeed less than 500 knots (mean 275 knots).

In this series 6 ejectees (24%) had clinical and radiographic evidence of vetebral compression fractures. These injuries were located in the thoracic and thoracolumbar spine. 4 cases required surgery ( indicated for angular kyphosis greater than 30 degrees, significant spinal canal compromise, greater than 50% or neurological injury. 1 patient had significant neurological compromise, following an AO A3.3 injury involving the L2 vertebra.

11 ejectees (45 %) had MRI evidence of a combined total of 22 occult thoracic and lumbar fractures. The majority of these ejectees with occult injury had multilevel injuries.

This study confirms a high incidence if spinal fracture and particularly occult spinal injury. Evidently vertical emergency aircraft ejection imposes major insults on the spinal column. Once, appropriately prioritised, life preservation measures have been undertaken, an early MRI of the spne is mandatory as part of comprehensive patient evaluation.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

A. Ramasamy S.E. Harrisson M.P.M. Stewart

The conflict in Iraq has evolved from a conventional war in April 2003 to a guerrilla-based insurgency. We investigated whether this change altered the pattern of wounding and types of injuries seen in casualties presenting to a military field hospital.

From January 2006 – October 2006, data was collected on all casualties who presented to the sole British field hospital in the region following injury from hostile action (HA).

86 casualties presented with injuries from hostile action (HA). 3 subsequently died of wounds (DOW – 3.5%). 46 (53.5%) casualties had their initial surgery performed by British military surgeons. 20 casualties (23.2%) sustained gunshot wounds, 63 (73.3%) suffered injuries from fragmentation weapons and 3 (3.5%) casualties sustained injury from blunt trauma. These casualties sustained a total 232 wounds (mean 2.38) affecting an average 2.4 anatomical locations per patient.

The current insurgency illustrates the likely evolution of modern urban conflict. Discrete attacks from improvised explosive devices (IED’s) have become the predominant cause of injury. These tactics have been employed against both military and civilian targets. With the current threat from terrorism, both military and civilian surgeons should be aware of the spectrum and management of the injuries caused.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

J.W. Heywood

The aim of the study was to investigate the attitudes and beliefs of military physiotherapists utilising the ‘Health care providers beliefs attitudes and impairments scale’ devised by Rainville et al (1994). The scale is a valid and reliable tool which indicates the likelihood of advice given to patients with a low back pain is either pro active or fear avoidant. The scale has been utilised amongst health care professionals and has shown a high degree of correlation with patient vignettes. A high score on the HC- PAIRS, is indicative of that advice given to patients is generally fear avoidant and cautious. Conversely, a low score supports current research and indicates that pro-active advice is more likely to be given to the patient.

The HC PAIRS questionnaire was distributed to all 90 military physiotherapists currently serving in a clinical role. The questionnaire was accompanied by a letter explaining that the nature of the study and requesting the questionnaire be completed and that the biographical information of gender, rank, age range, years military service, years physiotherapy experience, qualification to practice as a physiotherapist and highest academic qualification obtained be recorded.

A total of 83 returns were received. Statistical analysis was undertaken using the SPSS (version 14) statistical package. Results indicated a mean score of 50.86(SD 10.189). Military service equated to a mean of 8.86 years (SD 9.153), whilst physiotherapy experience gave a mean of 8.87 years (SD 6.327). Further statistical analysis was undertaken to establish whether there was a correlation between any of the biographical data collected and of the HC-PAIRS score. No correlation of statistical significance was identified in any of the categories.

The results obtained from the military physiotherapists are very similar to those obtained in similar studies utilising civilian physiotherapists, moderately fear avoidant. Attitudes and beliefs would appear to be developed very early in the physiotherapist’s career, exposure to both clinical experience and military culture would appear to have minimal impact on these beliefs. This has important implications when changes to traditional management strategies are being considered and implemented.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

K. Brown c. Featherstone J. Clasper

There are well-established guidelines for musculoskeletal and connective tissue disorders in the assessment of potential recruits. There have been no critical appraisals of the application of these guidelines since their recent revision. The aim of this study was to examine whether common presenting conditions are covered by the guidelines and whether there was adherence by the assessor to the recommended outcome. We reviewed 110 potential recruits presenting to an Orthopaedic Consultant. There were a number of conditions not covered and a few occasions when the decision seemed contrary to the guidelines. In particular we think more consideration is needed of congenital deformities.

B. Bains K Mangat K Porter

The femur is the largest and strongest bone with a very good blood supply. Large forces are required to result in a fracture. However once a fracture does occur, there can be significant displacement due to the strong musculature surrounding it and loss of blood. As a result of this, the patients are prone to neurovascular and circulatory compromise, which can lead to significant mortality and morbidity. In an open fracture, there is the added potential for infection.

We have conducted a case review of military patients with femoral fractures sustained in hostile zones admitted to RCDM for definitive treatment.

Retrospective analysis of military patients with femoral fractures admitted to RCDM. Factors to be considered include mechanism of injury, type of fracture (Gustillo Anderson and AO classification), pre- and post-transfer operative treatment, complications, microbiology, length of hospital stay, and discharge status. The presentation will include case discussion of interesting patients.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

S.A.C. Morris N Walker J Round D Edwards S.A. Stapley A.J. Langdown

Coronal alignment is an important factor in long-term survival of TKA. Many implant systems are available and most aim to produce a posterior slope on the tibial component to reproduce the 70 seen in the normal tibia. We hypothesized that resecting the tibial plateau with a posterior slope can introduce error in coronal plane alignment in TKA.

We used a standard saw-bones model in conjunction with a computer navigation system that is available for use in TKA (Stryker Orthopaedics). The normal protocol for preliminary referencing was followed; care was taken to identify tibial landmarks (tibial plateau reference point, true sagittal plane and transmalleolar axis). We then used a standard extramedullary alignment jig (Scorpio TKR System, Stryker Orthopaedics) with cutting blocks designed to give 0, 3, 5 and 7 degrees of posterior slope and varied the position of the alignment jig.

Variations included:

Medial rotation of the cutting block,

Medialisation of the plateau reference point,

Mediolateral translation of the distal jig, and

External rotation of the distal jig.

In all experiments, there was a greater deviation from ideal coronal alignment as the slope on the tibial cut was increased. The greatest influence was with external rotation of the distal part of the jig, which produced 30 of varus at only 150 of external rotation with a 70 slope. Medialisation of the proximal reference point worsened this to 4.50 of varus.

We have quantified the degree of coronal malalignment that can occur for different posterior slopes during tibial resection for TKA. We recommend either using a minimal slope or navigation to ensure correct implant positioning.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

N.M. Walker L.B. Cannon

Cigarette smoking is well recognised as contributing to a higher complication rate following foot surgery. The efficacy of pre-operative counselling to stop smoking has not been evaluated following foot surgery. The purpose of this study was to determine the effectiveness of pre-operative counselling prior to elective forefoot surgery.

A record of smoking status was taken in all patients prior to surgery. Counselling as to the increased complication rate was undertaken by the lead surgeon at the initial outpatient visit and repeated at pre-operative assessment, with patients advised to see their GP for specific strategies and medications. Further smoking history was taken on admission and in review clinics. A telephone survey was then conducted to ascertain smoking patterns following surgery.

Ninety-eight patients underwent forefoot osteotomy or fusion surgery, over an eighteen-month period, by a single surgeon. Of these, twenty-four were recorded as smokers, with follow-up, at a mean interval of twelve months, achieved in twenty-two. Sixteen stopped smoking pre-operatively, with a further four reducing their daily intake as a direct consequence of the counselling. The majority of patients were unaware of the detrimental effects of smoking following foot surgery. Only four patients re-commenced pre-operative smoking patterns following surgery implying long-term behaviour change in the remainder. One complication of a DVT was recorded in a persistent smoker.

This small study has illustrated the benefit of utilizing the pre-operative clinic consultation to educate our patients of the importance of giving up smoking prior to elective surgery. Counselling has been shown to provide an incentive for smoking cessation, which has been maintained after the peri-operative period. Although forefoot fusions and arthrodeses were used to provide the figures in our study, the results are transferable to other branches of foot and ankle surgery.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

M. Butler M. Shyam S.W. Parsons

Arthroscopy of the ankle and subtalar joints are established techniques in foot and ankle surgery. Arthroscopic ankle arthrodesis is well described and is useful in patients with a poor soft tissue envelope. Subtalar fusion is traditionally an open procedure with potentially significant complications but there is little published on arthroscopic subtalar arthrodesis.

22 patients, made up of 9 males and13 females were operated on from March 2004 to present day with 12 to 36 months follow up. Indications for surgery included primary osteoarthritis and degeneration secondary to previous calcaneal fracture, tibialis posterior insufficiency, neurological conditions and previous ankle fusion. 8 Patients had a concurrent arthroscopic ankle fusion and 4 patients also had a talonavicular fusion.

All patients had surgery by the senior author and followed the same postoperative course. Patients were protected in plaster for 12 weeks with gradual increase to fully weightbearing at 6 weeks and x-rays taken at 6 and 12 weeks. Successful outcome was taken as clinical and radiological evidence of fusion.

21 patients (95.5%) achieved fusion by 12 weeks. There has been 1 nonunion but there have been no wound breakdowns, deep infections or other serious complications.

Previous authors have reported variable complication rates and significant rates of delayed and non-unions following open subtalar fusion. These early results suggest that arthroscopic subtalar fusion is a safe and reliable method with a high success rate and a low complication rate.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

S. McGillion L.B. Cannon

Ankle arthroscopy is generally performed through anterior portals and provides good access to the anterior aspect of the ankle joint. However, the structure of the talus and the anatomical confines of the ankle joint limit access to posterior structures via this approach.

Developments in the technique of posterior ankle arthroscopy have determined the appropriate site for portals with minimal risk of iatrogenic neurovascular injury. This facilitates treatment of conditions such as flexor hallucis longus (FHL) release, excision of os trigonum for posterior impingement, treatment of retro-calcaneal bursitis and treatment of ankle and subtalar joint pathology.

Posterior ankle arthroscopy is a relatively new technique and has recently been adopted by the senior author. This study was performed to explore the benefits and limitations of this procedure and to identify early post operative results.

We describe our experience of this technique in treating 9 patients with varied posterior ankle pathology. 2 patients had excision of os trigonum; 2 had FHL release; 1 had both excision of os trigonum and FHL release; 3 had curettage for posterior osteochondral defect (OCD) of the talus; and 1 had resection of Haglund’s deformity. The mean pre-operative AOFAS scores (Ankle-Hindfoot Scale) was 73 (range 47 to 85). The mean post operative AOFAS score at 3 months was 82 (range 75 to 87). 4 patients had recent surgery and await follow up. There were no complications. Two cases exposed the limitations of this procedure: Incomplete resection of (i) a Haglund’s deformity required conversion to an open excision and (ii) a posteromedial OCD lesion will require further anterior ankle arthroscopy due to inadequate exposure.

We conclude that for the experienced arthroscopic surgeon this is a safe technique that facilitates treatment of a variety of ankle and hindfoot problems that would otherwise require open procedures.

D.E. Hinsley W.F.M. Jackson H.C.L Oag T.N. Theologis C.L.M.H. Gibbons H. Giele

Young active patients with malignant tumours arising in the distal fibula, requiring excision, present a challenge to the treating surgeon. Wide local excision is advocated, to achieve clearance, however, disruption of the ankle mortise results and fusion is often required to restore stability. The loss of movement is poorly tolerated in the younger patient and leads to progressive degenerative changes in surrounding joints.

Excision of the distal fibula lesion followed by harvesting of the proximal fibula and using this graft to recreate the ankle mortise restores ankle stability and retains ankle movement.

Between 1998 and 2007, we have performed this technique on 4 patients. Diagnoses were Ewing’s sarcoma, chondrosarcoma, parosteal osteosarcoma and osteofibrous dysplasia. To date there has been no evidence of distant or local recurrence. One case was complicated by infection, which resolved with radical debridement and antibiotics; the other three fibula grafts survived. Good to excellent results were achieved.

We will present the technical aspects of this procedure, with particular reference to the most recent case, performed on a young female patient with parosteal osteosarcoma.

We believe this technique provides good oncological and functional results and recommend this treatment option is considered in young active patients requiring distal fibula excisions for sarcoma.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

W. Eardley A. Mountain P. Baker

Presentation and subsequent publication has become ‘the holy grail’ of surgical trainees. This perceived importance of presenting work is further reinforced by the fact that over sixty percent of information contained in standard orthopaedic texts is quoted from published abstracts and not full papers. There is concern that increasing reliance is placed on such work and there are calls to restrict the routine use of abstracts in this manner.

This concern is born out of evidence that conversion of presented work into peer-reviewed publication is globally poor throughout the medical specialities.

The purpose of this study is to determine the conversion rate of work presented at the Combined Services Orthopaedic Society into peer review publication.

A Medline search of 81 consecutive published abstracts over six years was carried out. Further cross-referencing was established using Dialog Datastar with a search strategy. The rate of publication of papers presented at these meetings was then compared against other medical specialities across national and international forums.

26 full paper publications were identified. This yields a conversion rate of 32%. This figure is on a par with meetings such as the BOA (35%), the AAOS (34%) and EFORT (40%). It is also a similar level to that seen with work presented at other speciality meetings.

The conversion rate of papers presented at the Combined Services Orthopaedic Society is competitive with other orthopaedic and medical meetings. Overall conversion of presented works to robust literature is poor. Reasons for low publication rates include pressures of time, insufficient planning and disputes amongst colleagues.

In light of increasing pressure on selection of trainees and the perceived need to present work at meetings, this paper reinforces the need for thorough planning when undertaking research & audit and strict acceptance criteria from organising bodies.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

L. Ball J.J. Matthews A. Rosewarne P.J. Cox

Our study looked at the short and medium-term results of a new and cost-effective method of bone surface preparation and cement introduction. Early failure and loosening of components in knee arthroplasty has been attributed to inadequate bone-cement and prosthesis- cement interfaces, established at the time of surgery. Cement pressurisation and interosseus suction have been shown to achieve effective cement penetration and interdigitation into cancellous bone.

We have devised a technique of cement pressurisation using a modified 20 ml syringe, combined with interosseus suction. Retrospective evaluation of a series of 50 post-operative radiographs of total knee replacements, undertaken without the use of tourniquet, have shown that even and effective penetration of cement to a depth of 8.0 10.6 mm can be achieved consistently using this technique. Evaluation of post-operative radiographs at a minimum of 5 years follow-up showed 16 knees with minor lucent lines about the tibial component with a maximum Knee Society Total Knee Arthroplasty Roentgenographic Score of 2.

In conclusion, we propose that this simple technique of bone surface preparation and cement introduction produces good results in the short and medium term.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.

D Shivarathre N Kaimal H George LA James

Aim: To describe the epidemiology of paediatric bone infections in a single health district in England with particular reference to incidence and the changing pattern of the disease.

Method: Cases of chronic osteomyelitis and chronic regional multifocal osteomyelitis were excluded leaving 53 children diagnosed with acute haematological osteomyelitis (AHO) at a paediatric orthopaedic unit between January 2000 and December 2005. Patients were identified from the hospital coding system using the keywords ‘bone infection’ and ‘osteomyelitis’. The data were collected retrospectively from the patients’ hospital records and included demographic information, the delay between symptoms and presentation, clinical presentation, site of infection, organisms identified and laboratory results.

Results: The mean age of presentation was 40 months (range 0.5–179). The highest age incidence was between 0–3 yrs. There was no sex predilection with 27 girls and 26 boys. The mean duration of symptoms before presentation was 3.4 days (range 0–14 days). The presenting symptoms were pain at the affected site in 100% of cases, pyrexia (temperature > 38°C) in 47.1%, swelling of the affected site in 47.1%. The commonest bone affected was the femoral metaphysis. The commonest bacterium isolated was staphylococcus aureus. WBC, CRP and ESR were elevated in 44%, 84% and 92.1 % of the cases respectively. Plain radiographs and bone scan demonstrated signs of osteomyelitis in 32.1% and 78.8 % respectively. Surgical intervention was required in 21 patients.

Conclusions: The demographics and clinical presentation of AHO has not changed over the years. The commonest organism involved remains Staphylococcus aureus. ESR and bone scans were the most sensitive screening test for diagnosing the condition. Early initiation of third generation cephalosporin antibiotic therapy and surgical decompression, when necessary, was the mainstay of treatment.

C Senior E Gent

Aim: To present the features of PVL toxin positive staphylococcus causing osteomyelitis in children and its management.

Method: Two cases of PVL MSSA osteomyelitis have presented to our institute within the last six months. The first, a 15 year old boy presented with an abscess and surrounding cellulitis on the lower right leg following a skin abrasion sustained whilst playing football. He was recognized as being systemically unwell with extremely elevated inflammatory markers. Radiographic investigations demonstrated osteomyelitis.

The second case was that of an 11 year old girl who developed cellulitis of the lower thigh, but was not as systemically unwell as the first case. Radiographs again demonstrated osteomyelitis.

Results: Both children were treated with intravenous antibiotics and supportive measures and made a full recovery.

Conclusions: Panton Valentine Leukocidin (PVL) is a toxic substance produced by some strains of Staphylococcus aureus with an increased ability to cause disease. Although more common in the United States, less than 2% of all S. aureus infections in the UK carry the toxin. PVL can be carried both by MRSA (methicillin resistant) and MSSA (methicillin sensitive) Staphylococcus aureus.

Patients normally present with cellulitis, abscesses, boils and carbuncles. However, on rare occasions, more severe invasive infections result, including septic arthritis, bacteraemia or necrotizing pneumonia.

We feel that osteomyelitis caused by PVL positive MSSA is associated with more severe local disease and a greater systemic inflammatory response than osteomyelitis caused by PVL negative MSSA. Treatment is effective but needs to be initiated promptly to prevent significant complications.

DJ Dowen J Clark PD Henman

Aim: To present the features and management of Pyogenic myositis in children.

Method: Two boys of four and six years old presented to our hospital within 6 months. The initial presentation suggested septic arthritis of the hip with pain, pyrexia and limited hip movements. Serum inflammatory markers were significantly raised. Hip rotation, however, was not severely reduced when examined carefully. Neither case demonstrated an effusion on ultrasound of the hip joint. The diagnosis was made on magnetic resonance imaging which produced striking images. Staphylococcus aureus was isolated from blood cultures in each case.

Results: Both children settled with antibiotic treatment alone. The bacterial strain in the second case was of a type requiring combination antibiotic therapy for effective treatment.

Conclusions: Pyogenic myositis is not a common diagnosis in previously healthy children presenting with hip pain. It is a condition that has been reported more frequently recently and which should have a higher profile since it is probably under-diagnosed. Urgent magnetic resonance imaging is recommended for atypical cases of musculoskeletal infection in children. Care must be taken to prescribe antibiotic therapy appropriate to the particular bacterial strain.

H K Sugathan R D Duncan

Aim: To study the epidemiology, diagnostic criteria and outcome of Septic Arthritis (SA) of hip in infancy and childhood

Method: Retrospective case notes review of 43 cases of Primary SA of hip. Diagnostic criteria used: 1. Confirmed SA: positive joint fluid culture/positive blood culture and elevated WCC in joint fluid / radiological changes. 2. Presumed SA: Negative cultures but elevated WCC in joint fluid. The outcome was rated as A. Satisfactory: clinically and radiology normal hip. B. Unpredictable: clinically normal hip with radiological changes. C. Unsatisfactory: clinically abnormal hip.

Results: We had 37 cases of confirmed SA and 6 cases of presumed SA. Mean age of presentation was 4 years with male to female ratio of 3:2. All cases had either joint aspiration or arthrotomy. The 25% of cases with negative joint fluid cultures had a history of recent antibiotic use. Radiological changes were found in 40% cases. Mean duration of follow up was 33 months. Outcome was rated as satisfactory in 61%, unsatisfactory in 7% and unpredictable in 31%. Of confirmed SA cases 57% had a satisfactory outcome. The delay in the initial presentation was more than a week in all cases with unsatisfactory results.

Conclusions: Our study outlines the demographic and microbiological profile of SA of the hip in children. Diagnosis in culture negative cases can be challenging, especially with a history of recent antibiotic use. Prolonged initial delay in presentation was associated with unsatisfactory outcomes.

A Brodie S Jones J Fernandes R Rajan

Aim: To assess the ease of use and reliability of PICC lines for the delivery of intravenous antibiotics in children with septic joints.

Method: Over a twelve month period 22 children with septic joints were prospectively recruited. All received open arthrotomy and washout prior to commencing antibiotic treatment. At the time of surgery, a PICC line was inserted. All children were given intravenous antibiotics for two weeks then oral antibiotics for four weeks. Inflammatory blood markers were reviewed regularly. Upon removal of the PICC line the tip was sent for microbiological testing.

Results: All 22 children made a full recovery with a minimum of twelve months follow up (range 12–20 months). All PICC line tips were negative for microbiological culture after 48 hours.

Conclusion: Peripheral cannulation for intravenous access in children can be challenging. Younger children have chubby limbs and often fragile veins. Even with the use of topical analgesics the procedure can be traumatic for a young child. A PICC line inserted at the time of the surgical washout of the infected joint seems an ideal solution. PICC lines are safe, reliable and allow for at least two weeks of intravenous access, avoiding the need for regular re-cannulation of children.

S Lipscombe M Cope R Davies S Saville N Garg C Bruce

Aim: To assess whether use of the Pavlik harness for the management of developmental dysplasia of the hip (DDH) can safely be discontinued without weaning.

Method: The study group comprised babies diagnosed with DDH at the Royal Liverpool Children’s hospital over a 10 year period, between January 1995 and August 2004. The decision to instigate treatment with a Pavlik harness was based upon the Graf grade. We used Graf IIB or worse as our treatment threshold for the use of the Pavlik harness. In our practice the harness was removed when the hips were ultrasonographically and clinically normal, without a period of weaning.

Results: There were 368 hips (273 babies) for analysis, 178 cases of unilateral DDH (128 left hips and 50 right hips) and 95 bilateral cases. Mean age at diagnosis was 59 days (range 1 – 187 days) with twenty-six patients presenting late after the usual 120 day time limit. Treatment with the Pavlik harness was successful in normalising 323 hips (87.8%). The Pavlik harness was unsuccessful in reducing 45 dislocations (12.2%). Patients were followed-up for a mean of 4.1 ± 2.7 years with no deterioration of acetabular indices on plane radiographs, according to the Tonnis classification. There were 4 hips with possible grade I avascular necrosis. To date there have been no cases of late dysplasia.

Conclusions: Although many units remove the harness after a period of gradual weaning, practice is varied. Since we did not encounter any negative outcome despite not weaning we conclude that that weaning is unnecessary.

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A. Lakdawala C. Mauffery C. Carpenter J. Clegg

Introduction: Despite worldwide vaccination programmes Polio is still endemic in some developing countries. Numerous new cases of polio are seen every year in India resulting in significant childhood deformity. The Rotary Club funds voluntary camps aimed at correcting deformities in children. I was part of the surgical team in Jan 2007 led by Mr. J. Clegg.

Clinical experience: Some 141 procedures were carried out in 3 days, 99 by SPR’s under senior supervision. The most frequent procedure was a supra-condylar femoral osteotomy, followed by hip and knee soft tissue releases. For more complex operations we assisted or observed. Some deformity corrections were for non-polio cases. Interesting cases in the OPD included skeletal dysplasias, rickets and congenital deformities.

Conclusion: At the time where MMC restricts overseas training opportunities, I believe this type of mini-fellowship provides valuable experience. Training programmes should have such opportunities available to all trainees.

Q Choudry R W Paton

Aim: To assess the relationship between different types of foot deformity as risk factors in developmental dysplasia of the hip.

Methods: In the Blackburn district foot deformities were referred as risk factors in a screening programme for DDH. All hips were imaged ultrasonographically using a modified Graf morphological and Harcke dynamic method: type I, II, III and IV.

Statistical analysis compared relative risks, odds ratios, 95% confidence intervals for relative risk and P values using Chi the squared test.

Results: Total 585 cases, 432 postural equinovarus deformities (TEV), 60 fixed congenital talipes equinovarus (CTEV), 93 congenital talipes calcaneovalgus (CTCV) & 25 metatarsus adductus.

Conclusion: Routine screening for DDH in cases of postural TEV & fixed CTEV is no longer advocated. The deformity of postural TEV is poorly defined in the literature leading to over diagnosis. The screening of CTCV & metatarsus adductus should continue.

P. Nunag R. Duncan N. Wilson

Aim: To assess the efficacy of selective ultrasound screening for DDH, with and without an orthopaedic examination.

Method: From 2002 our secondary DDH screening program was changed. Newborns with risk factors were referred directly for hip ultrasound. The orthopaedic surgeon was not involved if ultrasound was normal. An audit for 1997–2001 found an average annual incidence of 0.57(29 cases). The audit was extended to 2005 by identifying late DDH cases presenting from 2002 onwards, using the same criteria.

Results: Ninety-six cases were identified. After excluding children born outside Glasgow 36 cases were left for audit. The yearly incidence per 1000 live-births is shown below. The average incidence for 2002–2005 was 0.95. No significant difference between the two periods was found (p= 0.3).

Average age at diagnosis was 14.9 months. Two had risk factors but had not been screened. Thirty-one hips were dislocated, two were subluxed and one had borderline dysplasia that resolved. Twenty needed open reduction. Sixteen of 22 patients over 1 year at treatment required open reduction compared to 5 of 13 treated age 1 year or less (p = 0.046). Ten had femoral osteotomy, five a pelvic osteotomy, and five both femoral and pelvic osteotomy. There was one postoperative infection.

Conclusion: Direct ultrasound screening of infants with risk factors without concomitant assessment by an orthopaedic surgeon has not significantly altered the incidence of late DDH.

S Lipscombe C Bruce

Aim: To demonstrate that the conservative management of meralgia paraesthetica in children is effective.

Method: Clinic case-notes of the senior author (CB) were retrospectively searched between January 1997 and February 2007 to identify cases of meralgia paraesthetica. Sixteen cases were discovered in fourteen patients, 6 right, 6 left, and 2 bilateral. Four patients had had previous pelvic surgery and two combined pelvic and femoral osteotomy for developmental dysplasia of the hip. One underwent bilateral pinning for slipped upper femoral epiphyses. Clinical symptoms were assessed subjectively. All patients were initially managed conservatively with NSAIDs and counselled to avoid tight fitting clothing across the waist. If symptoms had failed to settle at follow-up a local anaesthetic/steroid injection was administered to the site of maximal tenderness. Surgical decompression was performed for intractable cases.

Results: There were 10 females and 4 males, with a mean age of 13.6 years (8–17). Mean follow-up was 15 months (1–50).

Eleven cases (68.8%) improved with conservative management and a further three cases improved following a local anaesthetic/steroid injection. Two cases (12.5%) who did not improve with these measures underwent surgical decompression with subsequent improvement in symptoms. No side effects were reported from the either the steroid injection or surgical decompression.

Conclusions: There is no current evidence supporting the management of meralgia paraesthetica in children. In adults, this elusive diagnosis is managed conservatively to good effect. This retrospective study demonstrates that conservative management is also effective in paediatric patients. In those cases where symptoms prove intractable, surgical decompression produces clinical improvement.

A. W. Murray N. I. L. Wilson

Aim: Since obesity is thought to be an aetiological factor for SCFE we have looked to see if the ‘Obesity epidemic’ in children has been associated with a similar trend in SCFE.

Method: A population based study, using a national database of NHS Scotland activity, was undertaken to analyse trends in SCFE from 1981 to 2005 and to look for a relationship with changes in obesity in Scotland. Data on the body mass indices of Scottish school children have been collected as part of the child Health Surveillance Programme.

Results: We found that the incidence of SCFE increased from 3.78 per 100,000 children in 1981 to 9.66 per 100,000 children in 2000 (R2 = 0.715) – a two and a half fold increase over two decades. Furthermore, SCFE was seen at younger ages with a fall in the average age at diagnosis from 13.4 to 12.6 years for boys (p=0.007) and 12.2 to 11.6 for girls (p=0.047). SCFE is rare in young children – for 1981–1990 only two children presented with the diagnosis between the ages of six and eight; however for 1991–2000 seven presented in this age group. Along with the rest of the UK, the two decades we studied had seen markedly rising childhood obesity rates in Scotland. The prevalence of overweight (BMI> 85th centile) 13–15 year old children doubled from 15% in 1981 to 29% in 2001 and the problem extends to 4 and 5 year olds, although it is not of the same severity.

Conclusion: The incidence of SCFE has increase two and a half times in two decades and may well be a consequence of the worsening obesity rates that have occurred over the same period.

V S Ranawat K Rosendahl D H A Jones

Aim: To study the adequacy of reduction of DDH postoperatively using MRI.

Method: Ten consecutive children with DDH who underwent open reduction and femoral osteotomy using Coventry stainless steel implants were scanned postoperatively.

Results: MRI gave reliable diagnostic information in all cases. The position of the femoral head in the acetabulum was clearly seen, despite artefact due to the metal. The mean scanning time was 3 minutes 45 seconds (range: 2 minutes 20 seconds – 5 minutes 30 seconds) and the total time in the MRI suite was between 7 and 10 minutes. No child required sedation.

Conclusions: The use of MRI scanning has been described after closed and open reduction of the hip in DDH to check hip position but has not previously been reported after open reduction with femoral osteotomy and the use of metalwork. Satisfactory images, comparable time and cost to CT scanning and the lack of exposure to ionising radiation make MRI an appealing method of imaging. We recommend it as the investigation of choice in this patient group.

S Lipscombe S Saville L James C Bruce

Aim: To assess the effectiveness of a physiotherapist led normal variant clinic for children.

Method: The study comprised all children presenting to the physiotherapy clinic at the Royal Liverpool Children’s hospital between January 2000 and January 2006. The clinic is run by two specialist physiotherapists alongside a consultant led Orthopaedic clinic, providing support as required. Physiotherapy staff are able to request and interpret radiographs and order blood tests independently. The numbers of patients, the range of conditions seen in the clinic, and the outcome of the consultations recorded in the practitioner case-notes were examined for the purpose of this study.

Complete data was available for the full period under review except for the year 2003.

Results: During the five year study period 1594 children were seen, a mean of 318 patients annually (range 267–387). The age distribution of patients was 33.1% (527) under the age of 2, 38.9% (620) 2–5 years, 19.3% (307) 5–10 years and 8.8% (140) 10–16 years. The most common conditions seen were genu valgum 28.7% (458), genu varum 18.4% (293), in-toeing 14.7% (234) and toe walking 6.0% (96). Most patients (94.7% n=1509) were managed independent of consultant supervision by the physiotherapist. A minority of patients required consultant review in the clinic (4.2% n=67). Fewer still were referred to another medical clinic (1.1% n=18).

Conclusions: Children with a spectrum of orthopaedic conditions can be appropriately managed by a trained physiotherapist independent of consultant input.

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J Dickson A C Watts J E Robb

Aim: To review the epidemiology, prognostic factors and outcome of treatment for extra-osseous Ewing’s sarcoma.

Method: Thirty-four patients with a diagnosis of extra-osseous Ewing’s sarcoma were identified from a prospectively gathered national tumour database between 1961 and 2005. Patient demographics, clinical features, tumour stage, location and size, treatment received, local recurrence, metastasis and survival were all recorded. Survival was analysed using Kaplan-Meier methods. The average follow up was 45 months.

Results: The annual incidence of extra-osseous Ewing’s was 0.2 per million of population between 1970 and 2004. The five-year survival rate for extra-osseous Ewing’s was 62%, which is significantly better than previously reported in the literature. Indicators of a poor prognosis were extra-compartment spread of tumour, local recurrence and metastasis. The recorded annual incidence of extra-osseous Ewing’s sarcoma increased during the period of this study.

Conclusions: Extra-osseous Ewing’s sarcoma appears to have similar demographics and the outcome following modern treatment is better than previously reported and no worse than that reported for osseous Ewing’s.

K M Valentine M G Uglow N M P Clarke

Aim: To compare the rate of relapse of Ponseti treatment method with a historical cohort who underwent conventional surgery.

Method and Results: From June 2002 to December 2004, 70 patients presented with 107 clubfeet and started the Ponseti treatment method. 15 feet in 9 patients were excluded due to teratologic deformity. 50 patients with 75 clubfeet were studied (41 boys and 9 girls). There was at least a two-year follow up period, or failure of the Ponseti method within this time frame. Data was compiled from clinic assessment forms and patient notes. All cases resulting in recasting or further surgical procedures were regarded as failure of conservative treatment. This was compared to published data from the same centre, regarding relapse for the two-stage surgical method. From 1988 to 1995, 86 patients presented with 120 clubfeet and had surgical treatment. 68 patients with 91 clubfeet (48 boys 20 girls) had the two-stage surgical procedure and were followed up at a mean age of 5.7 years (2.2 to 9.6). The mean age for surgery was 8.9 months.

Relapse rate of both treatment methods was compared for all feet in all Dimeglio grades. Relapse rates for Ponseti and surgery respectively were: grade 2, 18.2% vs 0%; grade 3, 36.2% vs 20.4%; grade 4, 35.3% vs 65.4%. The differences were not statistically significant

Conclusions: The Ponseti method is as valid as the two-stage surgical method for the treatment of clubfoot. Functional outcomes of the two treatment methods need to be compared.

A A Qureshi A Roberts

Aim: To assess the Interobserver Reliability of the Sauvegrain Skeletal Age Assessment

Methods and Results: Elbow radiographs requested to exclude injury were anonymised. Sixteen examinations were assessed by ten independent orthopaedic specialist registrars or consultants. The Sauvegrain method as modified by Dimeglio was used to score the radiographs. The observations made were then assessed for interobserver reliability by means of a multiple observer Kappa score and the total scores by intra-class correlation coefficient.

Kappa scores for the components of the score were 0.403 for the lateral condyle; 0.492 for the trochlea; 0.354 for the proximal radius and 0.508 for the olecranon. Adding item scores to produce a modified Sauvegrain score had an intra-class reliability of 0.858 (95% CI 0.758 to 0.935).

Conclusions: Methods of identifying skeletal maturation and predicting future growth generally depend on the use of an atlas of hand radiographs. Difficulties with poor interobserver reliability associated with these methods have led to a move towards assessments that do not depend upon bone age estimations. Unfortunately plans based on ratios of growth or average patterns produce errors when unusual types of growth disturbance are present. We conclude that use of a scoring system for maturation assessed by elbow radiographs offers a significant advantage when substituted into the straight-line method of growth prediction. The Sauvegrain method as modified by Dimeglio1 has demonstrated an excellent level of interobserver reliability. We have used Sauvegrain scores to improve the accuracy of timing when using the Mosely straight-line method3.

D G Shivarathre R Shariff J Sampath A Bass

Aim: To report the clinical and radiological outcome of intramedullary fixation following corrective femoral diaphyseal derotational osteotomy, particularly in children with cerebral palsy.

Methods: We conducted a retrospective study of all femoral diaphyseal derotational osteotomies with Trigen antegrade intramedullary fixation (TAN system, Smith & Nephew) from April 2005 to June 2006. There were 9 patients with 14 affected limbs. The diagnosis was spastic diplegia in 8 of the 9 children, of whom 5 underwent the osteotomy as part of multilevel surgery.

Results: The mean age at surgery was 13.7 years (Range 11.2 – 17.3 years). The mean preoperative femoral anteversion was 43.6 degrees (Range 30 – 50 degrees) with the mean internal & external rotation being 61.6 (Range 50 – 70) & 8.3 (Range 0 – 20) degrees respectively. The average follow-up period was 9.5 months (Range 1.5 – 15 months). All patients mobilised with crutches in an average of 5 days (Range 3 – 12 days) and full weight bearing was achieved by 65 days (Range 45 – 150 days). Marked improvement in gait was noted in all children with postoperative mean internal & external rotation being 42.9 & 52.6 degrees respectively. There have been no instances of avascular necrosis or postoperative complications to date. Correction was maintained at the final follow up in all children with good bony union by 8 – 12 weeks.

Conclusion: The key to the success of femoral derotational osteotomy for correction of excessive femoral anteversion in children lies in achieving correction and early mobilisation. Intramedullary fixation following diaphyseal derotational osteotomy in children is a safe, effective, cosmetic and reliable procedure with rapid bony union, attributable to biological fixation and early mobilisation. Good early results have been obtained in children with cerebral palsy undergoing this procedure as a part of multilevel corrective surgery.

S B V Symons H K Graham

Aim: To improve our technique of subtalar fusion for the correction of flexible abducto-valgus foot deformities during single event multilevel surgery in children with cerebral palsy, specifically, to decrease operating time, avoid donor site morbidity, improve fusion rates and prevent loss of correction.

Methods and Results: The modifications are:

Preparation of the sinus tarsi using hemispherical reamers.

Grafting the sinus with a press fit, cortico-cancellous iliac crest allograft, cut with a circular “cookie cutter”.

Placing an 8mm titanium cannulated screw parallel to the talo-navicular and calcaneo-cuboid joints.

All patients had a preoperative instrumented gait analysis, video recordings of foot position, AP and lateral weight bearing radiographs.

Patients were encouraged to weight bear as tolerated in a cast at three weeks. Six weeks postoperatively the casts were replaced with ankle-foot orthoses. Gait laboratory reviews were conducted at 3, 6, 9, 12 and 24 months postoperatively with radiological evaluation of the subtalar fusion at 6, 12 and 24 months postoperatively.

Between January 2001 and December 2004, 58 children, mean age 9 years and 4 months underwent bilateral subtalar fusions with the modified technique during multilevel surgery. Fifty-eight patients were reviewed 12 months postoperatively and 54 at 24 months postoperatively.

Deformity correction was uniformly satisfactory. All patients had complete graft incorporation on plane radiographs. No patient required a revision procedure. Six patients subsequently had first metatarso-phalangeal joint fusions for symptomatic hallux valgus.

Conclusion: The reliability of extra-articular fusion of the subtalar joint improved dramatically using screw fixation and iliac crest graft as described by Dennyson and Fulford. This can be further improved by the use of hemispherical reamers to the sinus tarsi and cannulated screws for fixation of the talus to the os calcis. Allograft is a reliable substitute for autograft and is acceptable to most patients and families.

C. Lorincz R. Zernicke

Bones meet competing demands both structurally and metabolically with an ability to “functionally adapt” to the surrounding environment. Diets high in saturated fat and sucrose (HFS) can adversely affect bone by limiting calcium availability. Conversely, applying a mechanical stimulus, appropriate in magnitude, frequency, and rate has been shown to be osteogenic. Thus, we hypothesized that groups subject to a mechanical loading would incur skeletal benefits, whereas exposure to a HFS diet would adversely affect structural integrity. We also proposed that despite the osteogenic potential of loading stimuli, the calcium-limiting effects of a HFS diet would result in a net decrease in bone structural properties, when considered in combination.

Female mice underwent non-invasive exogenous cantilever bending of the right tibia with a 1Hz trapezoidal waveform for 60s, five days per week, for thee weeks. Loading was calibrated to induce peak strain magnitudes of 1000 microstrain. Mice were randomly assigned to one of two dietary cohorts: high-fat-sucrose (HFS, n=36) or adjusted starch diets (n=36). Mice were further subdivided into groups based on loading status: control, sham, or loaded. Upon sacrifice, tibiae were dissected; morphometrical and mechanical properties were assessed and compared.

Control mice fed a HFS diet had significantly reduced cross-sectional area, cortical thickness, maximal load, and energy to failure when compared to control mice fed the starch diet. No changes in material properties were seen. Mice eating a HFS diet as well as experiencing mechanical loading had significantly greater cross-sectional area, energy to failure, and maximal load when compared to control mice fed a HFS diet, but had reduced structural properties when compared with loaded mice within the starch cohort.

To date, bone structural properties, and not material properties were adversely affected as a result of ingesting a HFS diet. A diet effect was observed, between control mice fed a HFS diet and control mice fed a starch diet, with the former group experiencing the negative affects previously associated with HFS diets in rodents. Presently, a load effect was only observed within the HFS cohort.

T.L. Willett R.S. Labow J.M. Lee

Sprains and strains result from collagen fibre overextension. This study investigated changes in the molecular state of collagen due to overextension damage, thereby gaining insight into tissue degeneration and cellular detection of damage. Overextension results in intermolecular and intrafibrillar sliding, detected with x-ray diffraction. Tendon rupture results in increased susceptibility to proteolytic enzymes. These observations and contemporary theory concerning collagen fibre stability lead to the hypothesis that sub-rupture overextension should result in reduced thermal stability of fibrous collagen.

Tendons were harvested from steer tails. Each provided a specimen for control and for overextension. Sub-rupture overextension at 1%/s strain rate was accomplished on a mechanical testing system, under the control of custom software, until the slope of the force-deformation curve was approximately zero (before complete failure). Two loading treatments were tested: one-cycle and five-cycles. Two specimen types were tested: native tendons ± NaBH4 crosslink stabilization. Tendons in each of the four groups (2x2) were paired by originating tail. Thermal stability was assessed in terms of denaturation temperature (Td) using hydrothermal isometric tension testing. Specimens were held at constant length and heated from ambient temperature to 90degC. Td was defined as the temperature where load suddenly increased due to molecular unraveling and attempted shrinkage.

Overextension of native specimens reduced the thermal stability of the collagen (p< 0.0001) and five-cycles had a still greater effect (p=0.03). Td of controls was 64.5±1.0degC (mean±SD). After one-cycle, Td dropped to 63.2±1.0degC and, after five-cycles, Td dropped to 61.8±2.0degC. For stabilised tendons, the effect of multiple cycles was lost (p=0.08) but overstretching decreased Td by ~2degC (p< 0.0001).

This study confirms that the molecular state of collagen is altered by overextension damage, reducing Td by up to 10% of the expected range (37–65degC) in our experiments. This is thought to occur due to intermolecular sliding that liberates specific domains on the molecules, lowering the activation energy for uncoiling. These domains may also be key targets in degeneration and cell-collagen signaling.

R. Li E.H. Schemitsch D.J. Stewart H.P. von Schroeder

The purpose of this study was to develop a cell-based VEGF gene therapy in order to accelerate fracture healing and investigate the effect of VEGF on bone repair in vivo.

Twenty-one rabbits were studied. A ten millimeter segmental bone defect was created after twelve millimeter periosteal excision in the middle one third of each tibia and each tibia was plated. Primary cultured rabbit fibroblasts were transfected by use of SuperFect (Qiagen Inc) with pcDNA-VEGF. 5.0 X 106 cells in 1ml PBS were delivered via impregnated gelfoam into the fracture site. Experimental groups were:

Transfected fibroblasts with VEGF (n=7),

Fibroblasts alone (n=7), and

PBS only (n=7). The animals were sacrificed and fracture healing specimens collected at ten weeks post surgery

Radiology: Fracture healing was defined as those with bone bridging of the fracture defect. After ten weeks, fourteen tibial fractures were healed in total including six in group one, four in group two and four in group three. The VEGF group had an earlier initial sufficient volume of bridging new bone formation. Histological evaluation demonstrated ossification across the entire defect in response to the VEGF gene therapy, whereas the defects were predominantly fibrotic and sparsely ossified in groups two and three. Numerous positively stained (CD31) vessels were shown in the VEGF group. MicroCT evaluation showed complete bridging for the VEGF group, but incomplete healing for groups two and three. Micro-CT evaluation of the new bone structural parameters showed that the amount of new bone (volume of bone (VolB) x bone mineral density (BMD)), bone volume fractions (BVF), bone volume/tissues (BV/TV), trabecular thickness (Tb.Th), number (Tb.N) and connectivity density (Euler number) were higher; while structure model index (SMI), bone surface/bone volume (BS/BV), and trabecular separations (Tb.Sp) were lower in the VEGF group than the other groups. P-Values < 0.05 indicated statistical significance (ANOVA, SPSS) in all parameters except for SMI (0.089) and VolBx-BMD (0.197).

These results indicate that cell-based VEGF gene delivery has significant osteogenic and angiogenic effects and demonstrates the ability of cell based VEGF gene therapy to enhance healing of a critical sized defect in a long bone in rabbits.

R. Li E. H. Schemitsch D. J. Stewart H. P. von Schroeder

We sought to establish whether fibroblasts transfected ex vivo could be delivered via gelfoam impregnated with a solution of transfected cells to achieve local transgene expression in a fracture site.

A 10 millimeter segmental bone defect was created after 12 mm periosteal excision and plated in the middle one third of each rabbit tibia. Dermal tissues were obtained and fibroblasts were cultured with DMEM. Fibroblasts were labeled with CMTMR and 5x106 labeled fibroblasts in 1ml PBS with 1x1 cm? Impregnated gelfoam was placed into the fracture gap (n=2). Twenty four hours after cell injection, the rabbits were killed and specimens were harvested from the fractured leg. Using SuperFect (Qiagen Inc), the primary fibroblasts were transfected with pcDNA-VEGF which was generated with the full length coding sequence of the human VEGF gene. A convenient reporter gene, Efficiency Green Fluorescent Protein (EGFP), was used for monitoring transfection of VEGF by fluorescence intensity. Experimental rabbits received 5.0 X 106 VEGF transfected cells in 1 ml PBS via gelfoam at the fracture sites. The animals were sacrificed at seven days (n=4), fourteen days (n=4) and twenty-one days (n=4) post surgery and the fracture site specimens were collected for analysis.

The fluorescently labeled cells with CMTMR were found at the fracture site and surrounding tissues. It was demonstrated that the labeled cells were delivered into the fracture gap, bone marrow and muscle surrounding a segmental defect in the rabbit. In the VEGF group, visualised VEGF immunostaining (brown) was shown in the fracture site around the Gelfoam; as well VEGF was distributed at sites of endochondral ossification. Visible bone formation was shown: VEGF promoted new bone formation by VonKossa staining (dark) and produced numerous vessels by CD31 positive staining (brownish black). The VEGF protein was detected in and around the fracture by ELISA.

This data encourages the further development of genetic approaches using cell based VEGF gene transfer without viral vectors to promote fracture healing.

K. Hildebrand D. Hart M. Zhang

The hypothesis is that cells isolated from capsules of joints with contractures will contract collagen gels at a faster rate when compared to cells obtained from capsules of joints free of contractures.

Post-traumatic joint contractures were produced by removing cortical bone windows from the femoral condyles of three skeletally mature rabbits and immobilizing the knees for four weeks with a K-wire. The contralateral knees served as an unoperated control. At sacrifice, the posterior capsules were immediately placed in medium and the tissue was minced. Upon confluence, cells were trypsinised and gel contraction studies were carried out on passage four cells. Five x 105 cells/ml were mixed with 58% neutralised bovine collagen solution and five hundred microlitres of collagen gel/cells solution were then cast into wells of a tissue culture plate. Gelation occurred overnight at 37C in a humidified incubator containing 5% CO2. At cultured day zero, day one, day three, the gels were released from the well walls. The areas of the gel were measured using an image analyzer immediately after release (zero hour), and one hour, two hour, three hour and four hour post-release.

The amount the collagen gels were contracted depended on the time of preincubation of cells and collagen before release and the source of the joint capsule cells. In general, increasing the time of preincubation heightened the contractile response of the cells. The collagen gel contraction was small for the day zero groups over the first four hours, but for the day three groups the rate of contraction was markedly increased. In all cases the collagen gel contraction was larger for the contracture capsule cells when compared to the control capsule cells. The patterns of the contraction over the four hours post release were similar for contracture and control groups.

Cells from capsules of joints with post-traumatic contractures have intrinsically heightened in vitro contractile properties when compared to normal cells. Future work will determine whether the response is exaggerated to fibrotic stimuli such as TGF-beta1 in these capsule cells from post-traumatic joint contractures.

P. Guy P. Cripton P. M. de Bakker T. R. Oxland S. L. Manske

Evidence suggests that femoral neck fractures initiate in the superolateral cortex, where it is significantly thinner in older than younger individuals (Mayhew, et al. Lancet 2005). Thus, we sought to determine the relative time-course of crack initiation and propagation during a simulated hip fracture.

Four unembalmed frozen, human cadaveric specimens (mean age = 78 yrs) were loaded to failure in sideways fall configuration at a rate of 100 mm/sec using a materials testing system. Images of the fracture were captured with two high-speed video cameras at a resolution of 384x384 pixels, and sample rate of 9,111 Hz (frames/second).

Test A: The load-displacement (L-D) curve had three distinct peaks: at the first peak (4390 N), the head and neck rotated slightly. At the second peak (4607 N), a visible local compressive fracture appeared in the superior cortex of the proximal neck. At the third peak (3582 N), a neck-spanning tensile failure occurred in the inferior neck. Test B: At the first and second peak loads (1714 N and 3040 N) fluid was released from the posterior then superior and inferior surfaces. The third peak load (3361 N) corresponded to a local compressive failure in the lateral superior neck, followed by a neck-spanning tensile failure medially. Test C: The L-D curve was linear until ultimate load (3038 N). A compressive crack first appeared on the anterior-superior surface of the neck cortex, then fractured in the inferior neck. Test D: The L-D curve was linear until ultimate load. A small local crack appeared in the superior cortex of the proximal neck at ultimate load (3841 N).

We found that during ex vivo simulations of hip fracture, the femur failed initially in the superior cortex of the neck, and then failed in the inferior cortex. This is the first study to demonstrate, with high speed video data, the location of crack initiation and its propagation. These preliminary data support the hypothesis of Mayhew et al. (Mayhew, et al. Lancet 2005) in terms of fracture development and could relate to clinically relevant fracture types.

C. Panaro K. Bagnall R. Barley N. Jomha

Current research strategies for studying articular cartilage (AC) repair include the observation of chondrocyte behaviour in monolayer cultures, the use of artificial matrices and animal models. Since AC relies on the diffusion of joint synovial fluid for nourishment, we hypothesised that it should be possible to develop a research model in which full-depth AC explants are maintained under established tissue culture conditions. Successful maintenance of explants for prolonged periods of time would represent a novel approach and provide a very powerful research tool to address a wide range of chondrocyte biology and matrix synthesis questions. The objective of the project was to examine the cell viability within an AC explant model maintained in tissue media.

AC samples were obtained from the femoral condyles of total knee arthroplasty patients. Cylindrical dowels (10mm in diameter) were harvested from these samples. The dowels consisting of full-depth AC with several mm of subchondral bone attached were placed in tissue culture flask (T-25) containing 15mls of the respective culture media and maintained at 37oC in an incubator containing 5% CO2. Dowels were cultured in a variety of different media formulations (DMEM/F12, CGM (chondrocyte growth medium)) as well as PBS (phosphate buffered saline) which served as a negative control. AC chondrocyte viability was evaluated after five weeks. After having determined the best medium for cartilage maintenance, a second study with a broader range of end-points was undertaken. All dowels collected, rated 2/4 on the Outerbridge scale for osteoarthritis, and were then grown for zero, four, eight or twelve weeks in DMEM/F12 and CDM (chondrocyte differentiating medium). At each time interval, the dowels were evaluated for viability (live/dead stain), general morphology (trichrome stain), distribution of matrix proteins and proteoglycans (aggrecan, Types I and II collagen – immunofluorescence).

After five weeks in PBS, there were no viable cells in the explant. Viability in the explants maintained in DMEM/F12 was 71% compared to 59.6% in the CGM treatment. The viability of the cells in the second study was 90% with DMEM/F12. After twelve weeks, the explant models stained well for general morphology and the distribution of proteoglycans and collagen was well maintained.

To our surprise, the DMEM/F12 medium actually demonstrated the highest cell viability. Typically, AC requires joint motion to pressurise the synovial fluid into the matrix, which augments the transport of nutrients to the cells. Given that this study did not include any form fluid pressurization, it is surprising that such high cell viability was observed. This suggests that passive diffusion alone may provide adequate nourishment in this model system. In conclusion, the explant model for studying AC damage and repair examined in this research appears to be quite promising. This novel approach may serve as the foundation for subsequent research into new treatment strategies for AC injury.

Z. Westerbeek R. Hepple R. Zernicke

The purpose of this study was to examine the interactive effects of diet and the aging process on the mechanical and material properties of bone. We investigated how an ad libitum (AL) diet and 40% caloric restriction (CR) with nutrient supplementation, beginning at 3.5 months of age, interacted with the aging process to influence bone development. Diet effects were determined by measuring changes in bone geometry and bone mechanics of the tibia in young adult and senescent Fischer 344 X Brown-Norway Rats (F344 BN) rats.

Male F344 BN rats were divided into two dietary groups, AL or CR. CR commenced at 14 weeks of age, with 40% restriction and micronutrient supplementation. The AL group represented young adult (8 mo) and senescent (30–35 mo) rats. The CR group represented 8 mo and 35–40 mo rats. AL and CR groups were matched together for comparison based on the percentage survival rate. Tibiae were assessed using microcomputed tomography, mechanical testing, and ash analysis.

The results showed that a CR diet resulted in a significant decrease in total body mass when compared to the AL diet group across all ages. With aging, both AL and CR diet groups showed a general increase in structural properties and a decrease in material properties. Furthermore, material and structural properties changed proportionately between both diet groups. Comparisons between diet groups based on percentage survival rate revealed a significant decrease in most structural properties, but no significant changes in material properties with CR. After normalization to body mass, structural properties were significantly greater in the CR group when compared to the AL group.

The significantly greater CR structural properties over the AL diet group after normalization, with no significant changes in material properties, indicated that CR did not adversely affect the appendicular skeleton in F344 BN rats. Therefore, a CR diet with 40% restriction at fourteen weeks, with nutrient supplementation did not negatively impact tibial geometrical and mechanical properties in young and senescent male F344 BN rats.

N. Jomha A. Abazari J.A.W. Elliott G.K. Law L.E. McGann K. Rekieh

Effective cryopreservation of articular cartilage (AC) could improve clinical results of osteochondral allografting and provide a useful treatment alternative for large cartilage defects. Vitrification (a form of cryopreservation) incorporates high concentrations of cryoprotectant agents (CPAs) and rapid cooling rates to preserve cells in suspended animation without detrimental ice formation. Effective vitrification requires high concentrations of CPAs within the cartilage matrix but the time-dependent toxicity of CPAs hinders their usefulness. The objective of this experiment was determine the CPA permeation parameters for four commonly used CPAs. This data will enable the use of mathematical models to develop novel vitrification procedures to preserve AC. We hypothesised that the time dependency of CPA permeation into intact AC can be determined by exposing AC to CPAs for specific times and then allowing the CPA to be removed into a known volume of PBS, the osmolarity of which is then measured.

Full thickness 10mm diameter osteochondral dowels were harvested from the medial femoral condyles of sexually mature pigs. The dowels were randomly immersed in one of four CPAs (DMSO, propylene glycol, ethylene glycol, and glycerol) for various lengths of time (1–15 min). The cartilage was then immersed in 4ml of 1X PBS in a sealed container for twenty-four hours. The equilibrated solution was measured for osmolarity. The cartilage was weighed before and after treatment and this data was used to calculate the CPA concentration within the AC. This will be repeated in triplicate.

Preliminary results (minimum n=2) indicated a marked difference in permeation for the four CPAs. Ethylene glycol had the most rapid permeation with almost complete permeation (84%) within 15 min. Conversely, glycerol had the least permeation (29%) after 15 min most of which occurred within the first minute. DMSO (63%) and propylene glycol (40%) had intermediate rates of permeation that gradually increased over time.

Cryoprotectant agent permeation into intact porcine AC can be calculated using the method described in this study. This will allow us to successfully document the permeation kinetics of four commonly used CPAs within intact AC. This valuable data will markedly improve our ability to create novel vitrification solutions using mathematical models to add and remove CPAs to limit their toxic effects at high concentrations.

S. Gyomorey M. Butcher J. de Beer S. Shaughnessy M. Winemaker

To evaluate the mechanism by which orthopedic implant wear particles induce apoptosis in immature osteoblasts in an in-vitro setting.

Stromal cells from femurs of thirty day-old Swiss Webster Mice were isolated, cultured in-vitro, and incubated with orthopedic wear particles in the micrometer size range. After incubation with wear-particles, the cells were assessed for Caspase three expression and activity in the presence or absence of specific inhibitor(s) in order to delineate potential mechanism for cellular changes previously reported.

Here we report the induction of caspase three protein expression and activity with incubation of stromal cells with titanium wear particles. Caspase three activity however was not demonstrated to be up regulated in a time dependent manner or at lower concentration of particles (2 x 107 particles/ml). However, there was a significant (P< 0.05) increase in caspase three activity with titanium particle at higher concentration (4 x 107 particles/ml) that was not reversible when the extrinsic arm of the apoptotic pathway was blocked with anti-TNFƒa antibodies.

Our previous studies have suggested that aseptic loosening of orthopedic implants may be independent of inflammatory processes, and may be associated with induction of programmed cell death. Our current results would strengthen this idea by demonstrating induction of expression and activity of caspase three involved in apoptosis in cells incubated with wear particles. In addition, titanium wear particles may induce apoptosis through direct cellular effects rather than through the extrinsic TNFƒa pathway. Delineating the mechanism by which wear particles induce apoptosis in immature osteoblasts will allow for the selection and/or development of inhibitors to the process of asceptic loosening by targeting a specific pathway.

K. Hildebrand D. Hart P. Salo M. Zhang

The hypothesis is that mast cell numbers and neuropeptide containing nerve fibres are increased in the elbow joint anterior capsule of patients with post-traumatic contractures when compared to normal capsules.

Capsules were obtained from two patients with chronic contractures following radial head fractures and two organ donor elbows free of contractures. Four sections from each capsule were double-labelled with specific antibodies to the mast cell marker chymase and the neuropeptide calcitonin gene-related peptide (CGRP). Species specific secondary fluorescent antibodies were used to detect the marker antibodies and cells were identified with a fluorescent nuclear marker (DAPI). Images were captured using a microscope (200x magnification) and five randomly selected areas were sampled for each section obtained from all joint capsules. Chymase positive cell numbers and numbers of nerve fibers (minimum length fifty micrometres) were gathered.

The number of chymase positive mast cells was 6x greater in the contracture capsules when compared to normal capsules. In the contracture capsule, chymase positive mast cells represented 39% of total cells while in control capsules they represented 7% of total cells. Total cell numbers were similar in the capsules of both groups. The number of CGRP positive nerve fibres was increased 3x in the contracture capsule when compared to normal capsule.

Mast cell numbers and neuropeptide positive fibre numbers are increased in the elbow joint anterior capsule of patients with post-traumatic contractures when compared to normal tissues. Neuropeptides such as CGRP can induce mast cell degranulation. Mast cells release profibrotic molecules such as transforming growth factor beta1 (TGF-b1), a myofibroblast upregulator. It has been described that TGF-b1 and myofibroblast numbers are elevated in human elbow joint capsules in post-traumatic contractures. While these trends are encouraging, more subjects are needed to determine whether the mast cell and neuropeptide nerve fibre findings can be generalised to larger numbers. If future work supports a myofibroblast - mast cell - neuropeptide - fibrosis axis in the joint capsule in post-traumatic contractures, then methods to modulate this axis, such as mast cell stabilisers, may be evaluated in animal models.

C. Secretan K. Bagnall R. Barley N. Jomha H. Shum

Articular cartilage (AC) has a poor innate healing capacity following significant injury. Autologous chondrocyte implantation is a repair technique which utilises in vitro-expanded chondrocytes combined with a periosteal patch. The chondrocytes are enzymatically digested from arthroscopically harvested tissue at an initial surgery and expanded in monolayer culture prior to implantation at a second procedure. Unfortunately, in vitro expanded chondrocytes appear unable to retain their fundamental phenotype resulting in dedifferentiated cells which produce a matrix of inferior quality. This study compares the matrix-component gene expression profiles of chondrocytes in their native chondrons and through multiple divisions in monolayer culture. We hypothesised that there would be a rapid decline of matrix-component gene expression within a few cell replications in monolayer culture. The goal is to understand more fully the process of chondrocyte dedifferentiation and to compare matrix-component gene expression during cellular expansion in vitro.

Human AC was obtained from tissue donors and operative patients. A portion of the AC was stored at −80°C for use as a control while the remainder was homogenised and enzymatically digested with collagenase. The released cells were plated in monolayer culture and passaged (2:1) when they approached confluence. RNA was extracted from the frozen cartilage control and the passaged chondrogenic cell lines from which cDNA was generated. Real time PCR was performed with primers specific for collagen I, collagen II, aggrecan, and GAPDH. Gene expression was quantified and profiles from the cells in their native chondron and passaged cells (p0-p9) were compared.

Cells, when removed from the extra-cellular matrix and plated in monolayer, experienced an immediate upregulation of collagen I which persisted throughout all passages. In contrast, there was a stepwise decrease in collagen II with each successive passage until p8-p9 when the expression became undetectable. Aggrecan expression only decreased minimally as the cells were passaged.

Rapid dedifferentiation of monolayer cultured chondrocytes is a persistent barrier to AC tissue engineering including ACI. This study quantified the expression of relevant genes relating to AC generation and is an important first step to understanding cellular events, as alternative expansion techniques and cellular alternatives are sought.

L. Diamond M. Dunbar C. Hubley-Kozey W. Stanish K. J. Deluzio

The purpose of this study was to characterise the neuromuscular patterns associated with different severities of knee osteoarthritis (OA).

Forty-five patients with moderate OA, thirty-seven with severe OA and thirty-eight asymptomatic controls underwent a complete gait analysis with only the electromyographic (EMG) findings presented in this abstract. Severity levels were established through the Kellgren-Lawrence radiographic grading system, functional ability, and those classified with severe OA were tested within one-week of total knee replacement surgery. All OA patients had medial joint involvement. Subjects walked along a five-meter walkway a total of five times at a self- selected walking speed. Muscle activation patterns of the vastus medialis and lateralis, medial and lateral hamstring and medial and lateral gastrocnemius were recorded and normalised to maximum voluntary isometric contractions. All EMG waveforms were analyzed for group differences using PCA [1] followed by an ANOVA (group by muscle) for the PCA scores for each muscle group. These scores reflect both magnitude and shape changes.

The control group was significantly younger (53.3 ±9.5 yrs) and lighter (77.5 ±14.5 Kg) than the patient groups (Moderate =59.8 ±8.0 years and 94.2 ±19.2 Kg and Severe = 63.1 ±7.9 yrs and 95.8 ±14.6Kg). The severe OA group walked significantly slower (0.9 ±0.2 m/s) than the asymptomatic (1.3 ±0.1) m/s) and the moderate OA (1.2 ±0.2 m/s) groups. The PCA analysis of the EMG waveforms revealed statistically significant differences (P< 0.05) in patterns among the three groups and between muscles within the three muscle groups tested.

The neuromuscular differences found among groups during gait demonstrate that the role of the musculature surrounding the knee is altered slightly in those with moderate OA and altered drastically in those with end-stage OA compared to asymptomatic subjects, reflecting a progression. The differences are consistent with the severe group adopting a co-activation strategy of agonist and antagonists, more lateral activation and a reduction in plantar flexion during push off. These are consistent with strategies to increase dynamic stability and reduce medial joint loading. The moderate OA group illustrates a trend toward adopting this pattern but with only very subtle differences from asymptomatic subjects as has been previously reported. These neuromuscular alterations have implications with respect to muscle function and may assist in defining severity.

G. Fraser L.M. Ferriera J.A. Johnson G.J.W. King

This study examined the effect of wrist fracture deformities on the work and kinematics of forearm rotation in vitro.

An osteotomy was performed on eight fresh frozen upper extremities just proximal to the distal radioulnar joint and a three-degree of freedom modular implant designed to simulate distal radius fracture deformities was secured in place. This allowed for accurate adjustment of dorsal angulation, dorsal displacement, and radial shortening. The study was divided into two parts, the first phase examining the effects of distal radius deformity and the second sectioned the TFCC and repeated the testing, reviewing the effects of a progressive soft tissue injury in conjunction with distal radius deformity.

The magnitude of muscle activity required to achieve the motion, namely the work of rotation, was affected by the degree of simulated malunion and whether the TFCC was intact or sectioned. Increasing dorsal angulation caused a significant reduction in forearm pronation and supination. Once the TFCC ligaments were sectioned, the range of motion was restored to the pre-injured state for both pronation and supination. Dorsal displacement decreased the forearm range of motion significant at 10mm from native (p=0.02) and 5mm (p=0.03) for intact pronation. Radial shortening of 5mm or less had no effect on forearm rotation. However, 7.5mm of radial shortening could not be achieved in any of the specimens until the TFCC was divided.

Our results reveal that a significant loss of forearm rotation can be expected if a radius fracture exceeds thirty degrees dorsal angulation or 10mm of dorsal displacement. Radial shortening greater than 7.5mm could only be achieved concomitant with a TFCC rupture. This and further study in this area, should assist clinicians in developing treatment strategies for their patients with fractures and deformities of the distal radius.

D. Rutherford C. Hubley-Kozey W. Stanish NS Halifax K. Deluzio

Determine the association between net external knee adduction moment (KAM) characteristics and foot progression angle (FPA) in asymptomatic individuals and those with moderate and severe osteoarthritis through discrete variable and principal component analysis (PCA).

Fifty-nine asymptomatic (age 52 ± 10 years), fifty-five with moderate knee OA (age 60 ± 9 years) and sixty-one individuals with severe knee OA (age 67 ± 8 years, tested within one week of total knee replacement surgery) participated. Three-dimensional (3D) motion (Optotrak) and ground reaction force (AMTI) data were recorded during gait. Subjects walked at a self-selected velocity. The KAM, calculated using inverse dynamics was time normalised to one complete gait cycle. FPA was calculated using stance phase kinematic gait variables. The discrete variable, peak KAM, was extracted for the interval (30–60%) of the gait cycle. PCA was used to extract the predominant waveform features (Principal Components (PC)) of which PC-Scores were computed for each original waveform. Pearson Product Moment Correlations were calculated for the FPA and both the PC-scores and peak KAM. Alpha of 0.05 used to test significance.

No significant correlations were noted for the groups between peak KAM and the FPA, or for the first PC-Scores (PC1) of which captured the original KAM waveforms overall magnitude and shape. The second PC (PC2) captured the shape and magnitude during the second interval of stance (30–60%) with respect to the first. Correlations of FPA to PC2 were significant for the asymptomatic group(r=−0.40, p=0.002) and the moderate OA group (r=−0.32, p=0.017) but not for the severe group(r=−0.13, p=0.316).

No relationship between FPA and peak KAM was found across the groups using discrete variable analysis despite reports of associations in asymptomatic subjects. The PCA results suggest a toe out FPA was moderately correlated to a decreased KAM during 30–60% of the gait cycle for asymptomatic and moderate OA individuals only. These individuals respond to a toe out progression angle, altering the KAM which directly affects medial knee compartment loading, where those with severe OA do not.

E. Sled T. D. V. Cooke P. Costigan M. Lam L. Sheehy M. Nevitt D. Felson

This study determined the inter-reader and intra-reader reliability of lower limb frontal plane alignment measures obtained from digital radiographs using a computer software program.

Measurements of lower limb frontal plane alignment were obtained from over 3000 full limb digital radiographs of both limbs of persons ‘at risk’ for developing knee osteoarthritis (OA), as part of the Multicenter Osteoarthritis Study (MOST). Three trained clinicians used a computer software program (Horizon Image Viewer, version 1.5, OAISYS Medical Inc.) to locate bone landmarks on the femur and tibia from which standard measures of alignment (e.g. the Hip-Knee-Ankle (HKA) angle) and bone lengths could be computed.

To assess the reliability of these alignment measurements, one hundred randomly assigned digital radiographs, representing two hundred limbs, were selected from the complete data set for a repeated analysis carried out two or more weeks after completion of the first measurements. Random effects two-way analysis of variance (ANOVA) models were applied to estimate the interclass and intraclass correlation coefficients (ICC), which correspondingly evaluated inter-reader and intra-reader reliability for each of the angles and bone lengths.

High reliability measures were obtained for the HKA angle (inter-reader reliability: ICC=0.995 (95% CI, 0.994–1); intra-reader reliability: ICC= 0.998 (95% CI, 0.998–1)). Reliability for additional angles between the femur and tibia ranged from 0.839 to 0.993 (inter-reader reliability) and 0.908 to 0.998 (intra-reader reliability). High reliability measures were also obtained for bone lengths (inter-reader reliability: ICC from 0.993 to 0.995; intra-reader reliability: ICC from 0.994 to 0.995).

Each of the lower limb alignment and bone length measurements were highly reliable. The outcome supports the use of computer software programs and software tools for analysis of lower limb frontal plane alignment.

T. Jenkyn T. Bhatnagar T. Birmingham

Create an optimization model of the internal structure of the knee joint to quantify the correlation between external knee adduction moment (M[add]) during gait with the medial-to-lateral ratio of compartment loading (MLR). Patients were examined the week before, and six months after, surgical knee joint realigment with a high tibial osteotomy (HTO).

Thirty patients (six females, twenty-four males; age = 50.0 ± 9.4 yrs.; BMI = 30.0±2.8) with clinically diagnosed OA primarily affecting the medial compartment of the knee underwent a medial opening wedge HTO. Walking gait analysis was performed immediately pre-surgery and at six months post-surgery using optical motion analysis (eight Eagle camera EvaRT system, Motion Analysis Corp, Santa Rosa, CA, USA) and floor-mounted force plate (OR6, AMTI, Watertown, MA, USA). External joint kinetics were calculated using inverse dynamics. Kinematic and force plate data served as input for the internal knee joint model. The anatomical geometry was generic but scaled to patient height and knee alignment. Included were four ligaments (ACL, PCL, LCL, MCL), two contact surfaces (medial and lateral) and eleven muscles (quadriceps, hamstrings, gracilis, sartorius, popliteus and gatrocnemius). A loading solution was found to satisfy mechanical equilibrium and minimise the sum of squares of all structural loads. Output was the ratio of medial-to-lateral compartment compression (MLR). Paired t-tests compared M[add] pre-op versus post-op and MLR pre-op versus post-op. A Pearson R2 coefficient of determination was calculated correlating M[add] to MLR for the pre-operative condition.

Peak M[add] decreased from 2.53 ± 1.32 to 1.63 ± 0.81 [%body weight*ht] (p< 0.001). The peak MLR decreased from 2.63 ± 1.08 to 1.52 ± 0.56 [unit-less] (p< 0.001). There was a moderate correlation between M[add] and MLR with the Pearson R2=0.457 (p=0.014).

These results suggest that adduction moment is an acceptable proxy for quantifying the internal compressive loading in the knee. Even without considering muscle loading and possible co-contraction of antagonists, adduction moment explains nearly half of the variance in the internal loading of the knee joint compartments. However, further research is required with a larger sample size to increase confidence in this proxy measure in a clinical setting.

T. Jenkyn K. Anas C. Dombroski S. Robbins

Optical motion analysis (MA) is a useful tool for evaluating musculoskeletal function in health and disease. MA is particularly useful in quantifying joint kinematic and kinetic abnormalities accompanying osteoarthritis. However, current practice does not allow the joints of the foot to be measured since the foot is treated as a single rigid segment. To develop a multi-segment kinematic model of the foot for use in a clinical motion analysis laboratory. Apply the model to a healthy population during normal walking and gait intentionally disrupted by a high arch orthotic.

The foot was defined as five rigid segments: hindfoot (calcaneus), midfoot (tarsus), medial forefoot (first metatarsal), lateral forefoot (fifth metatarsal) and the hallux (both phalanges). Each of these segments were tracked individually using custom-built marker triads attached to the skin. Thirty healthy subjects (eleven male, nineteen female; mean age 27.7 years, range 19–53) were examined using MA (eight Eagle camera, EvaRt system, Motion Analysis Corp., Santa Rosa, CA, USA) during normal walking and gait disrupted with a high arch orthotic taped to the plantar surface. All trials were performed barefoot. The special foot marker system was applied to the right foot with the remaining markers in the Helen Hayes configuration. Three motions are reported. The hallux-medial forefoot angulation (HA) is reported in the sagittal plane (plantar-dorsiflexion). The hindfoot-midfoot angulation (HFA) is also reported in the sagittal plane (plantar-dorsiflexion). The height-to-length ratio of the medial-longitudinal arch (MLA) is reported, normalised to zero in quiet standing. Paired t-tests compared the normal and disrupted gait conditions. All angles were compared at the instant of foot flat.

HA was not significantly changed between normal and disrupted conditions: from 8.5° ± 6.4° to 8.6° ± 7.4° (p=0.88). The HFA plantar-flexion significantly increased from 0.5 ° ± 3.3° (normal) to 2.9° ± 4.4° (disrupted; p< 0.01); mean difference = +2.5° (95% CI: 0.81 to 4.1°). The MLA was significantly increased (arch raised) from 0.004 ± 0.018 (normal) to 0.017 ± 0.021 (disrupted; p< 0.01); mean increase = +0.012 (95% CI: 0.00421 to 0.021).

A multi-segment kinematic model of the foot has been successfully implemented in an optical motion analysis laboratory. The model was sensitive to an intentional disruption of normal foot kinematics during walking in a healthy population.

R. Newell C.L. Hubley-Kozey W.D. Stanish K.J. Deluzio

The knee adduction moment is indicative of the degree of medial compartmental loading at the knee joint and has been related to the presence and progression of knee osteoarthritis (OA). Studies have reported differences between OA and asymptomatic groups when measuring the adduction moment at the knee; however, there have been various biomechanical models used to describe this moment. In addition, non-invasive interventions have been shown to decrease the adduction moment but only at certain portions of the gait cycle. The objective of the study was to determine if changing the biomechanical model would affect the ability to detect differences between OA and asymptomatic gait and whether these differences depended on which portion of the gait cycle was analysed.

The gait of forty-four asymptomatic and forty-four moderate OA subjects was measured. The adduction moment was calculated using three different biomechanical models commonly used in the literature:

a 2D representation of the lower limb,

a 3D coordinate system based in the tibia, and

a 3D coordinate system based in both the tibia and femur. The adduction moment waveforms were compared between groups for various portions of the gait cycle for all three models.

The choice of biomechanical model changed the overall magnitude and shape of the adduction moment waveform. These changes affected the ability to detect group differences using commonly reported parameters of the adduction moment. However, group separation was achieved (regardless of model) when analyzing the overall magnitude of the adduction moment across stance phase and the mid-stance portion of the gait cycle.

These results demonstrate that the OA subjects are not unloading the medial compartment of the knee at full weight acceptance as well as the healthy controls. Furthermore, the OA subjects are experiencing a higher medial compartment load that is being sustained for the duration of the stance phase of the gait cycle. Group differences that are not model dependent may be important in understanding the pathomechanics of OA and evaluating interventions. These findings support the need for a better understanding of the anatomical mechanisms associated with the adduction moment.

J. Astephen M. J. Dunbar K. J. Deluzio

To study the association between hip and ankle biomechanics during gait and moderate knee osteoarthritis (OA).

Gait analysis was performed on a group of forty-four patients clinically diagnosed with moderate knee OA, and on a group of sixty asymptomatic subjects. Three-dimensional net joint angles and net joint reaction moments at the hip, knee and ankle joints were calculated. Peak values were extracted from the gait waveform patterns and compared between the two subject groups with Student’s t-tests.

The peak hip extension moment, the peak hip adduction moment, the peak hip internal and external rotation moments, and the peak ankle dorsiflexion and plantarflexion moments were all reduced in the knee osteoarthritis population compared to the asymptomatic population.

Differences in knee joint loading patterns with moderate knee osteoarthritis have been previously reported, but these data suggest that changes in the mechanical environment of all lower extremity joints are associated with early stages of knee osteoarthritis. Other studies have associated reduced peak hip adduction moments with reduced likelihood of OA progression. These data provide a rationale for hip abductor muscle strengthening as a means to lower knee joint loading.

A. Lawendy A. Badhwar A. Bihari D. Gray N. Parry D. Sanders

Elevated intracompartmental pressure (ICP) results in tissue damage due to impaired microcirculatory function. The nature of microcirculatory impairment in elevated ICP is not well understood. This study was designed to measure the effects of increased ICP on skeletal muscle microcirculation, inflammation and cell viability using intravital videomicroscopy.

Twenty adult male Wistar rats were randomised to four groups: the control group (control) had no intervention; while three experimental groups had elevated ICP maintained for fifteen (15m), 45 (45m), or ninety (90m) minutes. Compartment pressure was continuously monitored and controlled between 30¡V40mmHg in the posterior hindlimb using saline infusion into the anterior hindlimb. Mean arterial pressure was maintained between 80 and 120mmHg. Fasciotomy was then performed and the Extensor Digitorum Longus muscle studied using intravital videomicroscopy. Perfusion was measured by comparing the numbers of continuous, intermittent, and nonperfused capillaries. Inflammation was measured by counting the number of activated (rolling and adherent) leukocytes in post-capillary venules. Muscle cellular Injury was measured using fluorescent vital staining of injured cell nuclei.

Perfusion: The number of continuously perfused capillaries decreased from 77 ± 3/mm (control) to 46 ± 10/mm (15m),40±10/mm(45m)and27±8/mm(90m)(p< 0.05). Non-perfused capillaries increased from 13 ± 1 (control) to 16 ± 4 (15m), 30 ± 7 (45m), and 39 ± 5 (90m) (p< 0.05). Inflammation: Activated leukocytes increased from 3.6 ± 0.7/(100ƒÝ)2 (control) to 5.9 ± 1.3 (15m), 8.6 ± 1.8 (45m), and 10.9 ± 3.0/(100ƒÝ)2 (90m) (p< 0.01). Injury: The proportion of injured cells increased from 5 ± 2 % in the control group to 12 ± 3 (15m), 16 ± 7 (45m) and 20 ± 3 % (90m) (p< 0.05).

As little as fifteen minutes of 30mmHg ICP caused irreversible muscle damage and microvascular dysfunction. With increased duration, further decreases in capillary perfusion and increases in injury are noted. A severe inflammatory response accompanies elevated ICP. The role of inflammation in compartment syndrome is unknown, but may contribute to cell injury and reduced capillary perfusion.

G. Hatfield M. Dunbar C. Hubley-Kozey K. J. Deluzio

To compare strength and recruitment of periarticular knee muscles in subjects with severe osteoarthritis (OA) one week before and one year after a total knee replacement (TKR).

Twenty-eight subjects, mean age = 64.5 years, with severe knee OA performed maximum voluntary isometric contractions for six exercises designed to test knee flexor and extensor and plantarflexor muscle strength. Torque and surface electromyograms (EMG) from the lateral and medial gastrocnemius, lateral and medial hamstring, vastus lateralis and medialis and rectus femoris muscles were recorded. Exercises included knee extension and flexion at mid range (45°) and closed-pack (15°) positions and plantarflexion with knee extended. Subjects completed WOMAC questionnaires to assess function. Custom software written in Matlab version 7.0.4 was used to calculate muscle torque and process EMG data. Paired Student t-tests (alpha = 0.05) were used to detect significant differences between pre-test and post-test data. Statistical analyses were performed in Minitab.

Post-TKR torque increases ranged from 1.6% to 19.7%, but only knee extension with the subject’s knee at 45° showed a statistically significant (p< 0.05) increase (74.3 ± 29.5 Nm to 86.1 ± 28.5 Nm). EMG amplitudes increased for the quadriceps and hamstring muscles (p< 0.05) post TKR, but the relative contributions of each muscle did not change, excepting rectus femoris. Within each exercise, some subjects increased their torque, but almost as many decreased their post-TKR torque. WOMAC scores for pain, stiffness, and function improved significantly (p< 0.05) by one year after TKR.

TKR surgery is becoming more common as a treatment for OA, but few studies have examined muscle strength before and after, which impacts patient function and the lifespan of the implant. By one year post-TKR subjects reported significant decreases in pain and stiffness, and significant improvements in function. This is consistent with the literature. Half of the subjects decreased in muscle strength to levels lower than pre-surgery. The results provide evidence that post-TKR management must address muscular strength deficits in addition to subjective assessments of improved symptoms to measure success.

M. Lavigne J. Girard S. Mottard A. Roy P. A. Vendittoli

The purpose of this study was to compare the post operative ROM of patients randomised between SRA and 28mm THA.

Restoration of normal ROM has been proposed as an advantage of hip resurfacing (SRA) over THA and is due to the use of larger diameter femoral heads. However, the head-neck diameter ratio, which is an important factor governing ROM, would in theory allow more ROM with THA (28mm head/14mm neck = ratio 2:1) versus SRA (approximate ratio 1.3–2.0:1).

Patients were randomised between SRA and THA. Osseous landmarks were identified with a marker pen. Both ASIS served as the reference line for the pelvis position. Digital photographs of hip motion were taken and a blinded rater (with respect to the side and type of surgery) performed range of motion testing on the operated and normal side. Pre-study validation of ROM measurement method with a software program revealed high intra and inter observer reliability.

Sixty SRA and sixty-two THA were evaluated at minimum follow-up of twelve months. Preoperative ROM and demographic data were similar for both groups. No significant differences (p> 0.05) were found in the total arc of motion (SRA=204.2°, THA=196.5°), arc of rotation (SRA=47.7°, THA=44.3°), flexion-extension arc (SRA=118.1, THA=120.1), abduction-adduction arc (SRA=43.1°, THA=42.9°).

In theory, ROM should have been greater in THA. Fear of instability may have limited ROM recovery potential in THA. Since pre operative soft tissue contracture is an important factor influencing post operative ROM, the complete capsular release performed during SRA may have been an advantage of this technique.

E. Davis M. Olsen E. Schemitsch J. Waddell C. Webber

We aimed to establish if radiological parameters, dual energy x-ray absorbtiometry (DEXA) and quantitative CT (qCT) could predict the risk of sustaining a femoral neck fracture following hip resurfacing.

Twenty-one unilateral fresh frozen femurs were used. Each femur had a plain AP radiograph, DEXA scan and quantitative CT scan. Femurs were then prepared for a Birmingham Hip Resurfacing femoral component with the stem shaft angle equal to the native neck shaft angle. The femoral component was then cemented onto the prepared femoral head. No notching of the femoral neck occurred in any specimens. A repeat radiograph was performed to confirm the stem shaft angle. The femurs were then potted in a position of single leg stance and tested in the axial direction to failure using an Instron mechanical tester. The load to failure was then analysed with the radiological, DEXA and qCT parameters using multiple regression.

The strongest correlation with the load to failure values was the total mineral content of the femoral neck at the head/neck junction using qCT r= 0.74 (p< 0.001). This improved to r=0.76 (p< 0.001) when neck width was included in the analysis. The total bone mineral density measurement from the DEXA scan showed a correlation with the load to failure of r=0.69 (p< 0.001). Radiological parameters only moderately correlated with the load to failure values; neck width (r=0.55), head diameter (r= 0.49) and femoral off-set (r=0.3).

This study suggests that a patient’s risk of femoral neck fracture following hip resurfacing is most strongly correlated with total mineral content at the head/neck junction and bone mineral density. This biomechanical data suggests that the risk of post-operative femoral neck fracture may be most accurately identified with a pre-operative quantitative CT scan through the head/neck junction combined with the femoral neck width.

E. Davis P. Gallie M. Olsen E. Schemitsch J. Waddell

To assess the accuracy of plain digitised radiographic images for measurement of neck-shaft and stem-shaft angles in hip resurfacing arthroplasty.

Fifteen patients having undergone hip resurfacing arthroplasty with the Birmingham Hip Resurfacing (BHR) were selected at random. Digital radiographs were analyzed by three observers. Each observer measured the femoral neck-shaft angles (NSA) of the pre-operative and stem-shaft angles (SSA) of the postoperative radiographs on two separate occasions spanning one week. The effect of femur position on SSA measured by digital radiographs was also analyzed. A BHR prosthesis was cemented into a third generation Sawbone composite femur. Radiographs were taken with the synthetic specimen positioned in varying angles of both flexion and external rotation in increments of 10° ranging from 0° to 90°.

The mean intraobserver difference in measured angle was 3.13° (SD 2.37°, 95% CI +/−4.64°) for the NSA group and 1.49° (SD 2.28°, 95% CI +/−4.47°) for the SSA group. The intraclass correlation coefficient for the NSA group was 0.616 and for the SSA group was 0.855. Flexion of the synthetic femur of twenty degrees resulted in a five degree discrepancy in measured SSA and flexion of forty degrees resulted in a thirteen degree discrepancy. External rotation of the synthetic specimen of twenty and forty degrees resulted in a three and nine degree discrepancy in measured SSA, respectively.

Patient malposition during radiographic imaging can contribute to erroneous NSA and SSA results. Significant intra- and inter-observer variation was noted in the measurement of neck shaft angle however, variation was less marked for measurement of stem shaft angle.

M. Winemaker J. de Beer P. Gamble

Digital radiography has replaced traditional radiography in many hospitals yet little is known regarding the accuracy of this new technology in THA templating. Our study analyzed the reproducibility and reliability of computer templating in primary uncemented THA as compared to standard on-lay templating techniques with hardcopy radiographs from a digital source.

In December 2004 our hospital converted from standard hardcopy radiography to digital radiography. Patients undergoing THA had preoperative digital radiographs taken which included an AP pelvis with a 50mm magnification marker place in the groin, AP hip, and a cross-table lateral. Forty patients were selected that met our inclusion criteria to begin the templating process, including adequate placement of the magnification marker and optimal hip implant positioning on the postoperative films. Cases that did not have a marker, had significant deformity or mal-positioned implants were excluded. Hardcopies of digitised radiographs were printed and a traditional templating technique using 120% magnified on-lay transparent templates was performed (Capello, 1984). Digital templating was performed using OrthoView Software (Bono, 2004). Templating was conducted by two staff surgeons and one resident. Intra-observer and inter-observer effects were calculated using an Intraclass Correlation Coefficient (ICC).

Digital templating showed good inter-observer and intra-oberserver reliability with ICC values > 0.7. Using computer templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 80% of the cases.Using on-lay templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 60% of the cases.

There was a significant difference between the accuracy of acetabular cup templating between techniques, likely as a result of the ability of computer templating to adjust for magnification error. Computer templating was able to accurately predict postoperative leg-length discrepancy, abduction angle and horizontal offset. Overall, computer templating was found to be a reproducible and reliable technique for uncemented THA. Problems and lessons learned in the implementation of a digital templating system will be discussed.

K. Harato H. Matsumoto T. Nagura T. Otani Y. Suda Y. Toyama

The purpose of this study was to investigate the effect of knee flexion contracture on trunk kinematics.

Ten healthy old women, averaged sixty-two years, participated in this study. Subjects were tested at our laboratory with use of gait analysis system which consisted of eight retro-reflective markers (placed at bilateral acromion, anterior and posterior superior iliac spine, and iliaccrest), and five cameras. Unilateral (only right side) knee flexion contractures of zero, fifteen, and thirty degrees were simulated with a hard brace. All subjects performed walking trials at their preferred speed with or without simulation. First, level walking was measured without simulation, and then, with simulation at zero, fifteen and thirty degrees of flexion in order. Walking trials without brace was used as control. We evaluated walking velocity (m/s) and trunk kinematics (degrees). In the coronal plane, shoulder-pelvis bending angle was defined as the angle between shoulder girdle line and pelvic line. In the sagittal plane, anterior inclination of the trunk was defined by the slope linked right acromion and iliac crest, and anterior inclination of the pelvis was defined by the slope linked right superior anterior iliac spine and right superior posterior iliac spine. Shoulder-pelvis rotation angle was defined as the angle between shoulder girdle line and pelvic line in the axial plane. Maximum values were calculated.

Walking velocity was significantly decreased at thirty degrees contracture (1.19 at controls, 0.98 at thirty degrees contracture). In the coronal plane, trunk significantly tilted leftward rather (4.5) than rightward (1.8) at thirty degrees contracture. In the sagittal plane, trunk anterior inclination significantly increased at thirty degrees contracture (0.1 at controls, 3.1 at thirty degrees contracture). However, pelvic anterior inclination was similar. In the axial plane, trunk significantly rotated rightward (6.7) rather than leftward (4.3) at thirty degrees contracture.

Knee flexion contracture significantly influences physiological trunk kinematics in each plane. In particular, lateral bending to the contracture side was restricted, and this fact indicated that the lumbar spine may bend convexly to knee contracture side. These facts may result in Knee-Spine Syndrome.

G. Mackenzie D. Chess S. Deshpande J. Johnson A. Kedgley

Optimal soft tissue tension maximises function following total knee arthroplasty. Excessive tension may lead to stiffness and or pain, while inadequate tension can lead to instability. Composite component thickness is a prime determinant of this soft tissue tension. The variable component thickness provided by polyethylene inserts generally allows for 2–3mm incremental change. This study analyzed the effect of 1-mm incremental changes in polyethylene thickness on soft tissue tension. Our hypothesis was that soft tissue tension would be markedly affected by increases in insert thickness.

Computer assisted TKA was performed on eight cadaveric knee specimens (four pairs). The knees were passively moved through full flexion-extension range of motion, for each tibial construct thickness. Kinematics were recorded using the computer navigation software. Soft tissue tension was analyzed by measuring compartmental loads. A validated load cell instrumented tibial insert was used to measure medial and lateral compartmental loads independently. The effect of 1-mm increments in polyethylene thickness on compartmental loads was evaluated.

An increase in compartmental loads was measured with increasing insert thickness. Loading in contralateral compartments showed differing behaviour, reflecting varying tension in the medial and lateral sides. Many generated loads showed a reduction after reaching a maximal level with further increase in insert thickness (seven of eight specimens), indicative of tissue failure, although there were no overt indications of failure during the procedure. With a 1-mm increase in insert thickness, six of eight specimens showed an increase in peak loads greater than 100N at some point in the testing procedure, although not always with the same shim thickness.

Compartmental loads varied as a function of insert thickness. Most specimens showed signs of soft tissue “micro-failure”. The high sensitivity of compartmental loads to a 1-mm incremental increase is significant and has not been previously appreciated, especially intra-operatively. Currently available inserts with 2–3mm incremental sizes may make obtaining optimal soft tissue tension difficult. In addition to the current focus of obtaining accurate leg alignment, further computer-assisted techniques are required to address soft tissue tension.

S. Hunt S. Seal C. Stone

Comparison of two cementing techniques: femoral component insertion into early-cure stage cement and insertion into late-cure stage cement in an in vivo model to identify if cement cure stage affects the strength of the bone cement interface.

Bilateral arthroplasties – using only the femoral component - were performed in vivo on paired porcine femora. The femora were harvested and cross-sectioned in preparation for strength testing. Performance was measured by peak load required to push the femoral prosthesis and surrounding cement mantle free of the cancellous bone.

The mean failure load for prostheses inserted into late cure stage cement was 908 N +/− SD 420, whereas the mean failure load for the conjugate early cure stage cement was 503 N +/− SD 342. A paired t-test indicated significantly higher load failure rates in the late cure stage cement versus the early cure stage samples (t=2.37, p< 0.049).

Femoral component insertion into late cure stage cement required statistically significant higher loads for push-out when compared to femoral component insertion into early cure stage cement.

J. Brandt K. Charron S. MacDonald J. Marr J. Medley L. Zhao

Attempts have been made to develop standardise guidelines for knee implant wear testing of polyethylene (PE). The current ISO-14243-3 standard recommends the use “calf serum”, without giving ranges on the specific protein constituents and characteristics. In the present study, three types of frequently used calf sera with various protein constituents (albumin, globulins) were utilised. The effect of osmolality and hyaluronic acid (HA) was also assessed. An attempt was made to identify synovial fluid (SF) characteristics that may be responsible for the boundary lubrication in the joint with the goal to develop a more clinically relevant lubricant.

Twenty samples of SF were drawn from twenty patients and analyzed. Specific protein constituents and osmolality were then compared to three calf sera used for wear testing. Test One (six million cycles (Mc)): Bovine calf serum (BCS), newborn calf serum (NCS) and alpha-calf serum (ACS) were diluted with distilled water (DW). Test two (5.5Mc): ACS with an osmolality of 312 ± 1.00 mmol/kg (closest to clinical osmolality; diluted with phosphate buffered saline, PBS) and 145 ± 2.00 mmol/kg (diluted with DW) were consecutively tested. HA was added at a concentration of 1.5g/l. Modular total knee replacements of cruciate retaining design (GUR 1050, 10mm PE insert) were used.

ACS diluted with PBS appeared to be of closest specific protein constituents and osmolality when compared to SF. The wear rate for BCS was 21.81 ± 2.48 mg/Mc, 17.05 ± 3.25 mg/Mc for NCS, and 13.44 ± 0.79 mg/Mc for ACS (p < 0.016). Decreased osmolality amplified the PE wear by a factor of 2.3 (p = 0.020). Adding HA increased the PE wear by a factor of two (p = 0.002).

There was significant difference in PE wear rates between the three calf-sera. BCS and NBC did not have clinically relevant levels of specific protein constituents. This study strongly suggests that current standards for total knee wear testing should be revised to enable more controlled wear testing under more clinically relevant conditions. It is suggested to be of particular importance when new bearing materials, such as cross-linked PE’s, are evaluated and proposed for clinical application.

C.L. Hubley-Kozey K. J. Deluzio M. Dunbar R. S. Newell NS Halifax

The purpose of this investigation was to determine the changes in frontal plane kinetics (loading) and neuromuscular responses pre and post unilateral total knee replacement surgery (TKR) during walking.

Thirty-four patients with severe knee osteoarthritis (within one week prior to TKR surgery) underwent a gait analysis. 3D kinematics, kinetics and electromyographic (EMG) recruitment patterns from seven lower limb muscles (vastus medialis and lateralis, medial and lateral hamstrings, medial and lateral gastrocnemius and rectus femoris) were recorded while walking at their self-selected walking speed. This was repeated one-year post-TKR surgery. EMG data were normalised to maximum voluntary isometric contractions and the knee adduction moment was normalised to body mass. All waveforms were normalised in time to 100% of the gait cycle. Principal component analysis was applied to the pre-and post-TKR waveforms. T-tests and ANOVA models tested pre-post TKR differences and differences between muscles.

At pre-TKR, the average age of the subjects was 66 ± 6.6 years and there were no statistically significant differences between pre and post TKR measures of mass (90Kg). The walking velocity significantly (p< 0.05) increased from the pre-TKR (.9 ±.23 m/s) to the post-TRK (1.07 ±.21 m/s). There were statistically significantly (p< 0.05) magnitude and shape differences between the pre-and-post-TKR waveforms for the knee adduction moment and the EMG waveforms. In general there were reduced adduction moments and EMG amplitudes for quadriceps and hamstrings post-TKR.

The results show improved function with the increased walking velocity, but more important are the differences with respect to joint loading and muscle function. The decreased knee adduction moment post-TKR reflects reduced loading on the medial compartment of the prosthesis. The alterations in the quadriceps and hamstrings illustrate that post-TKR the muscles no longer co-activate at high percentage of their maximum during the majority of the gait cycle as was shown in the pre-TKR waveforms. Finally the high lateral hamstring activity found pre-operatively was reduced resulting in a more balanced activation between the medial and lateral sites post operatively. These post-TKR changes have implications for improved joint loading, reduced risk of muscle fatigue and decreased metabolic costs associated with walking.

R.L. Austman B. J.B. Beaton C. E. Dunning K. D. Gordon G. J.W. King C. E. Quenneville

Stress shielding (i.e. reduction in bone strains) in the distal ulna is commonly noted following ulnar head replacement arthroplasty. Optimal design parameters for distal ulnar implants, including the length of the stem, are currently unknown. The purpose of this study was to investigate the effect of stem length on bone strains along the length of the ulna.

Strain gauges were applied to each of eight cadaveric ulnae to measure bending loads at six locations along each ulna’s length (approximately 1.5, 2.5, 4.0, 6.0, 8.0, and 13.0cm from the ulnar head). The proximal portion of each bone was secured in a custom-designed jig. A materials testing machine applied loads (5–30N) to the ulnar head while native strains were recorded. The ulnar head was removed and the loading procedure repeated for cemented stainless steel stems 3 and 7cm in length, according to a previously reported technique (Austman et al, CORS 2006). Other stem lengths between 3 and 7cm were tested in 0.5cm intervals with a 20N load applied only. Data were analyzed using a two-way repeated measures ANOVA (á=0.05).

In general, distal bone strains increased as stem length decreased (e.g. average microstrains at the second distal-most gauges: 138±13 (7cm), 147±15 (6cm), 159±21 (5cm), 186±40 (4cm), 235±43 (3cm)). The native strains were different from all stem lengths for the four distal-most gauges (p< 0.05). No differences were found between any stem length and the native bone at the two proximal-most gauges. The 3cm stem replicated the native strains more closely than the 7cm, over all applied loads (e.g. average microstrains at the third gauge level for a 25N load: 357±59 (native), 396±74 (3cm), 257±34 (7cm)).

No stem length tested matched the native strains at all gauge locations. The 3cm stem results were closer to the native strains than the 7cm stem for all loads at gauges overtop of the stem. Overall, the 3cm stem produced the highest strains, and thus would likely result in less distal ulnar bone resorption after implantation. These results suggest that shorter (approximately 3cm) stems should be considered for distal ulnar implants to potentially reduce stress shielding, although this must be balanced by adequate stem length for fixation.

A. Sethi W. Hakeos S. Meisterling R. Vaidya R. Weir C. Wybo

The purpose of the study was to determine the effectiveness of rhBMP-2 when applied to an absorbable collagen sponge for interbody fusion with allograft spacers.

Seventy-seven consecutive patients requiring inter-body fusion with one hundred and eighteen levels were included in the study. In thirty-six patients cervical or lumbar interbody fusions were performed using allograft and rhBMP-2. In the remaing allograft was used with demineralised bone matrix. In patients undergoing anterior cervical decompression and fusion (ALIF) machined allograft spacers were supplemented with anterior locking plates. In those scheduled for anterior lumbar inter-body fusion (ALIF) or transforaminal lumbar interbody fusion (TLIF), machined allograft spacers were supplemented with posterior pedicle screw constructs. There were no stand alone ALIF procedures. All patients undergoing surgery were assessed preoperatively and at two weeks, six weeks, three, six, twelve, twenty-four months following surgery.Their Oswestry disability index (ODI) questionaires, Visual analogue scale (VAS) scores and a pain diagram were recorded. Radiographic measurements were made on the electronic public access computer system (EPACS).

All patients with allograft plus rhBMP-2 showed radiographic evidence of fusion by six months following surgery. The allograft with demineralised bone matrix group took considerably longer to achieve the same radiographic end plate appearance. Subsidence was obvious on radiographs in greater than 50% of cases with allograft and rhBMP-2 at three months. It was noted to occur between six weeks and three months and there was no significant subsidence after six months. This was statistically significant with a p< 0.0001 (fisher exact test). The average subsidence for the entire rhBMP-2 group at twelve months was 16.5%(SE 2.5% and range 0–58%) and for the allograft and bone matrix group was 4.6%(SE.74% range 0–15%)with a p< 0.0001 (independant t test).

Although high rates of fusion can be accomplished with allograft and rhBMP-2 (100%), significant subsidence occurs in greater than 50% of lumbar spine cases and 30% of cervical spine cases. This is possibly a result of early bone turnover with loss of structural support of the allograft spacer and end plate resorption.

M. Kunz R. E. Ellis L. Ploeg J. Rudan

For hip resurfacing arthroplasty, precise planning and implantation of the components is necessary for long-term success. Earlier studies have shown that a computer-assisted technique can achieve higher accuracy than conventional technique. However, many of the proposed computer systems add additional complexity, time and cost to the surgery. This study investigated the use of rapid prototyping as an accurate, fast and cost-effective solution for computer-aided hip resurfacing.

From a CT scan of each patient, a 3-dimensional computer model of the proximal femur was produced and the drilling trajectory for the central pin of the stem was planned. To transfer this plan to the patient, surface-matched plastic drilling templates were created using a rapid prototyping machine. Depending on the surgical approach, these templates contained a mirror-image of parts of the anterior or posterior femoral head and neck. These mirror-image templates helped to exactly position the drilling guide on the bone during surgery, which ensures a precise transformation of the preoperative plan into the surgical field. To test the accuracy and reproducibility of this system, we created plastic models of three cadaver femurs using the rapid prototyping machine. For each of these femurs one anterior and one posterior drilling template were generated. Each template was applied three times to the femur model and the direction of the drilling target was recorded and axis deviations measured.

The average deviation between the planned and the template-guided drill direction was 1.3° for the anterior approach and 1.2° for the posterior approach. The reproducibility for the drilling axis was measured for the anterior approach as 0.4° and posterior 0.3°.

In comparison to previous published results for computer-assisted hip resurfacing, our results show similar or better accuracy. Further in-vitro and in-vivo experiments will be performed to obtain statistically significant accuracy measurements and intraoperative feasibility tests. Our early results show great potential for this technique for accurate and in-expensive guidance for hip resurfacing.

A. Zahrai R. Rampersaud B. Ravi

To evaluate the clinical accuracy of computer-assisted fluoroscopy for the placement of percutaneous lumbosacral (LS) pedicle screws.

A prospective computed tomographic (CT) analysis was performed in forty consecutive patients. Three independent observers were utilised. Postoperative CT scans of one hundred and fifty-nine titanium pedicle screws (n = 6(L3); thirty-eight(L4); sixty-five(l5) and fifty(S1)) were reviewed. All screws were percutaneously placed using the two-dimensional FluoroNavTM system. The relative position of the screw to the pedicle was graded as follows: I-completely in; II – < 2mm breach; III - = 2–4mm breach; IV – > 4mm breach. The direction of the breach was further classified as well as its trajectory.

Correlation between observers was near perfect. The three observers rated 74.2%, 78.6%, and 78.0% of screws were completely contained within the pedicle. The data from the observer with the most significant pedicle breaches is as follows: thirty-five (22%) pedicle breaches (grade II -n=30; III - n=4; IV - n=1/n= 11 medial; n=19 lateral; 5 superior). Only one clinically significant breach occurred medially (grade III) at L5. This required screw revision (performed with a minimal access technique) with complete resolution of acute post-op L5 radiculopathy.

The in-vivo percutaneous pedicle breach rate in this study was higher than that reported for similar open navigational techniques. The majority (85.7%) of breaches were minor (< 2mm) and over half (54.3%) were lateral with no potential for clinical squealae. This high lateral breach rate is due to a modified lateral starting point required for the percutaneous technique. However, there is concern that this technique resulted in one clinically significant medial breach and highlights the increased risk associated with percutatneous pedicle screw placement. The findings of this study suggest that improved screw placement accuracy for minimal access instrumented fusions is required.

C.P. McDonald B. J. B. Beaton J. A. Johnson G. J. W. King T. M. Peters

Accurate implant alignment with the flexion-extension axis of the elbow is likely critical for optimal function and durability following elbow replacement arthroplasty. Implant alignment can be optimised by imaging the contralateral normal elbow prior to surgery and transferring this information to the diseased elbow in the operating room through registration. Successful registration is dependent on the presence of unique anatomical landmarks. Bone loss can create a challenge for registration as key anatomical landmarks are absent, limiting the number of sampling areas. This study investigated the effect of intraoperative sampling area on registration accuracy. We hypothesised that a low registration error can be achieved by acquiring surface data from areas unlikely compromised due to injury and readily available to the surgeon during typical surgical exposures.

CT images of twenty cadaveric distal humeri were acquired. Surface data was acquired from nineteen anatomical landmarks of the distal humerus using a hand-held laser scanner (FastSCANTM, Polhemus). Registration to the CT image was performed for thirty-nine landmark combinations. Only six combinations are discussed for succinctness.

Combining data from the anterior articular surface and humeral shaft, the lowest registration error was achieved in translation (0.8±0.3 mm) and rotation (0.3±0.2°). However, using data from the posterior shaft and proximal medial supracondylar column, a registration error of 1.1±0.2 mm and 0.4±0.2° was achieved.

Based on the results of this study, a low registration error can be achieved by acquiring data from two areas that are located proximal to the articular surface (the proximal medial supracondylar column and posterior humeral shaft), readily available surgically, and unlikely compromised due to distal humeral fractures, non-unions or bone loss due to severe erosive arthritis. Registration error was similar to the reported resolution of the laser scanner. Overall, this study demonstrates the promise for a successful registration of the contralateral normal elbow to physical surface data of the diseased or injured elbow using only a small portion of undamaged bone structure.

J. Haverstock M. Dunbar A. Hennigar L. Leahey NS Halifax

The purpose of this study was to assess the effect of total knee arthroplasty (TKA) on the gait symmetry of patients suffering from osteoarthritis. TKA is an effective method of relieving pain and restoring function but many established outcome measures are subjective and based on patient self-report. This study used clinical gait analysis with the Walkabout Portable Gait MonitorTM (WPGM) to describe pre and post-operative function in a more objective manner.

The WPGM is a tri-axial arrangement of accelerometers that a subject wears around the waist, approximating the position of the center of mass (COM). Twenty-one TKA patients underwent a standardised WPGM assessment (a walk at a self-selected speed along a 50m hospital corridor) and completed the WOMAC and SF-36 subjective questionnaires preoperatively and three years after surgery. Data was recorded at 200 Hz for approximately twenty to twenty-five seconds. Automated Fast Fourier transformations (FFT) of the displacement data in three axes yields data on the ‘repeating irregularities’ that result from musculoskeletal injury or compensatory mechanisms and provides three clinically significant ratios Surge (asymmetry in the gait cycle in the forward direction), Lurch (side to side displacements that becomes asymmetrical with unilateral pathology) and Functional Leg Length Difference (FLLD) (asymmetry in vertical displacement during the gait cycle).

Paired t-tests show that mean Surge (p< 0.006), FLLD (p< 0.0001) and Lurch (p< 0.008) were reduced following TKA for treatment of osteoarthritis. This is evidence that the asymmetry of gait was successfully reduced and subsequently overall gait was improved following surgical intervention. Patients’ WOMAC and SF-36 questionnaires showed significant improvements in patient pain, stiffness and physical function post-operatively (p’s< 0.01).

Advantages of using the WPGM in addition to standard patient self-report questionnaires include the ease of testing, quick analysis and ability to detect musculo-skeletal health changes that might otherwise be masked by extraneous variables. A small subset of patients did not realise significant improvement in gait parameters post-operatively. On closer inspection, these patients had near normal gait patterns pre-operatively. This suggests the WPGM has great potential for objectively prioritizing patients waiting for TKA and assessing post-operative outcome.

J.K. Mahood D. Hedden D.L.. Hill E. Lou M.J. Moreau J. Raso

To determine the pattern of brace wear compliance over time in both day and night time wear by using objective force measurements within the brace.

Twenty subjects who were diagnosed of AIS, age between nine and fifteen years, and new to brace treatment were recruited in this study. To use the data for analysis, only subjects who used the brace for five hours continuously either in daytime or nighttime were considered. For daytime wear, the selected five hour intervals had to begin with an initial spike in force after a period of non-activity as recorded by the transducer, which would indicate that they had just put on the brace. At night, the measurements began at one am and ended at six am.

Among the twenty subjects, only nine subjects’ data were used for daytime and eleven subjects’ data were used in nighttime. The average wear period was 11.4 ± 4.3 days for the day group, 11.6 ± 3.9 days for the night group. There was a statistically significant decrease in force within the first five hours of consecutive brace wear during daytime hours. The decrease was from 1.4 ± 0.6 (140% of prescribed force) in the first hour to 1.0 ± 0.6 in the fifth hour, a difference of 0.4, which is a 29% drop from the initial force. Most of the drop in force happened between hour one and hour two, as the difference in those two hours is 0.2 ± 0.1 (p = 0.001); between hours two and five the difference did not reach statistical significance. The observed difference between hours one and five for the night group was 0.2 ± 0.2, p = 0.06, which did not reach significance as well. Daytime forces in a Boston Brace tend to decrease over a period of time, but the nighttime forces seem to be maintained at the same level. These results show that daily adjustment of the brace tightness may be required to maintain the tightness level and the efficiency of brace treatment.

S.K. Bisland C. Johnson B. C. Wilson S. Burch

The purpose of the study was to examine the effects of vascular-targeted photodynamic therapy (PDT) using benzoporhyrin derivative (BPD) on growth plates in spine and long bones. Specifically we wish to determine whether the ipsilateral up-regulation of VEGF in the thoracic and/or lumbar spine following treatment with leads to onset of scoliosis morphologically similar to idiopathic adolescent scoliosis. And secondly confirm growth plate closure in long bones following BPD-PDT resulting in leg length discrepancy.

A 0.2 mm fiber was placed through an 18g needle onto one side of the distal femoral epiphysis (n=24) or lower thoracic/upper lumbar vertebral bodies of four-week old mice (n=18). Mice are genetically modified to emit bioluminescence upon activation of the vascular endothelial growth factor gene (VEGF). Accurate placement was confirmed using fluoroscopy. BPD (2 mg/Kg, i.v.) was administered systemically and the growth plates were stimulated with 690nm laser light five minutes later. Range of light dose regimens were tested. Animals were followed for a total of seven-twelve weeks post treatment. Faxitron imaging and bioluminescent imaging were obtained to determine leg length or curve progression and VEGF activity. Histology and immunohistochemistry including H& E, HIF-1á, CD31 and VEGF immunohistochemistry was performed.

PDT was able to up-regulate VEGF for up to four weeks following treatment following a percutaneous treatment using a 0.2mm treatment fiber both in the femur and vertebrae. Femoral shortening occurred with histological evidence of bone formation across the growth plate. We were able to identify using faxitron abnormal curvature in a number of the animals that received 5J, 10 mW regimen.

This study confirms that that the epiphyses of vertebrae and long bones are similarly susceptible to the effects of a hypoxic insult resulting in VEGF up-regulation. We are proposing that this stress response can lead to premature closure of epiphyseal growth plates of long bones resulting in limb growth arrest or asymmetric growth of vertebrae and the development of scoliosis in an animal model.

M. Stiebel P. Jarzem

Linear spinal cord distraction, in animal models, leads to elevated intra-compartmental spinal cord pressure. We developed an in vitro model of distraction, with increasing tensile force, to demonstrate the relationship between the degree of spinal curvature and the proportional elevation of intra-compartmental pressure.

Six Porcine spinal sections, two cervical, two thoracic, and two lumbar were harvested from 30kg pigs. These cord sections were individually stretched in a saline solution with increasing tensile force applied. Cord interstitial pressure (CIP) was monitored with an arterial line pressure monitor. The sections were each tested six times fresh, and then thawed and tested an additional six times. An additional ten freshly thawed cords were tested in linear distraction and over forty-five degree and ninety degree curved surfaces with CIP monitoring.

Increased tension, by adding increasing weights of distraction, lead to a proportionally elevated CIP in the linear model (R=0.986). We achieved a 99% confidence interval via paired T testing to demonstrate that there was no significant difference between fresh specimens and recently thawed cords. As the degree of spinal curvature increased from a linear model, to a forty-five and ninety degree (cobb) curve, there were significant increases in CIP at the same distraction force. The more significant the curve, the greater the CIP for each increment in distraction force; ninety degree curves produced a 2.3x higher pressure than linear distraction.

High cord interstitial pressure (CIP) can be achieved through spinal cord distraction (> 140mm Hg). This CIP is no only directly proportional to tension, but also proportionally magnified by the degree of spinal curvature. It is not affected by freezing/thawing. This may suggest that spinal cord compartment syndrome is a potential mechanism for spinal cord distraction injury, and these distraction pressures are potentially magnified in the setting of scoliosis.

M.J. Moreau D.L. Hill E. Lou J.K. Mahood J. Raso

Brace correction based upon mechanical action requires appropriate interface pressure between the body and the brace.

A smart orthotic was developed to record how much time (quantity) a brace was used, how well (quality) it was used and maintain the interface pressure to the prescribed level. Six subjects were recruited and they all used Boston style braces. Each subject used the system for two weeks without the force maintenance system activated to serve as the control period, and the remaining two weeks with the force maintenance system activated. During the automatic feedback mode, the pressure maintenance system was activated only during the daytime (8:00–22:00hrs) to avoid disturbing the patients during sleep. The subject could either return the system to us after one month or continue to use the system until the next clinic.

The time that the pressure level was in the target level range during the study period was increased from 53 +/− 9% to 68 +/− 14% with the feedback activated. The average brace wear time for the study period was 72 +/− 15% (12.6hr/day) of the prescribed time (17.5 +/− 3.8 hours). The curve severity of all subjects on the following clinical visit was the same (within measurement error) as the first visit (32 +/− 5 vs 31 +/− 5 degrees). Compliance was not affected when wearing the monitor.

The smart orthotic was able to improve the efficiency of a conventional brace by maintaining the prescribed interface pressure automatically. This proposed work helps brace candidates wear their braces more effectively and gets the most benefit from the brace treatment. As a result, all participated subjects maintained their Cobb angle within ± two degrees during the study period.

M.R. Hardisty M. Akens T. Skrinskas C. M. Whyne A. Yee ON Toronto

Rodents are often used as preclinical models for investigating the biomechanical consequences of spinal pathologies and interventions. Growth plates are present within rat vertebrae throughout life and may alter the vertebral biomechanics. This study investigates the biomechanical response of rat-tail vertebrae to axial compressive loading using μCT imaging and image registration to spatially resolve strain fields.

The sixth caudal vertebrae of eight immunocompromised (rnu/rnu) rats were μCT scanned (17.5 ×17.5×17.5μm/pixel) in both loaded (27N-32N axial compression) and unloaded configurations. Image registration was used to calculate strain and displacement fields in the bone due to the applied load by finding a spatial mapping between the two scans. Strain was resolved to varying spatial resolutions; high strain gradient regions, such as the growth plates, were analyzed to higher spatial resolutions.

Axial strains calculated by image registration ranged from 2% in tension to 16% in compression with an average axial strain of 1.6% in compression. In seven rats the majority of the strain measured within the vertebrae was concentrated in the growth plate. Very soft growth plates in three specimens resulted in maximum axial strains from 10–16% in compression. The remaining four rats with strain concentrations in the growth plate had maximum axial strains ranging from 2.2%–3.2%. Centrally located strain concentrations of lower magnitudes and more limited spatial extent were observed in the trabecular bone.

The majority of the strain within the rat vertebrae was absorbed by the growth plates. The amount of strain within the growth plate is important to consider when interpreting biomechanical data on rat vertebrae. Load application to rodent vertebrae will first compress the growth plate and only following compression of this structure cause significant development of displacement and strains within the trabecular and cortical bone. This insight into the biomechanical response of rat vertebrae is apparent through the application of image registration to analyse vertebral body behaviour; such information would not be evident in analysing preclinical whole vertebral body response using finite element modeling or experimental testing protocols.

M.K. Akens S. K. Bisland A. Karotki C. Whyne B. C. Wilson A. J. Yee

Bone is the preferred site of metastases in women with breast cancer, which can cause skeletal-related events (SRE¡¦s) such as pathologic fractures. Bisphosphonates are the current standard of care for treatment of meta-static bone disease by preventing further bone destruction. Photodynamic therapy (PDT) has been applied successfully as a non-radiative treatment for malignancies. In PDT, light is delivered to a tumour after the administration of a photosensitiser. Earlier pre-clinical studies in a metastatic rat model have shown that PDT reduced the tumour burden in the vertebrae. The goal of this investigation was to study the effect of PDT on bisphosphonate pre-treated cancer in-vitro.

Human breast cancer cells, MT-1, were cultured until confluent. The following groups were formed: no treatment; incubation with zoledronic acid (24h; 10 ƒÝmol) only; PDT treatment only and incubation with zoledronic acid and PDT treatment. Prior to light application 1 microg/ml of the photosensitiser BPD-MA was added. PDT was performed with a light dose of 1J and 10 J. The cells were stained with a live/dead stain and analyzed by fluorescence microscope and flowcytometry.

Incubation of the MT-1 carcinoma cells with bisphosphonate zoledronic acid resulted in a significantly higher number of dying cells following PDT treatment when compared cells that were not treated by zoledronic acid (p< 0.05). When comparing cell groups that did not undergo PDT treatment the incubation with zoledronic acid alone did not have a statistically significant effect on cell survival twenty-four hours following zoledronic acid administration.

In-vitro, breast cancer cells appear more susceptible to PDT after they have been incubated with the zoledronic acid. Zoledronic acid, a potent bisphosphonate, inhibits farsenylpyrophosphate (FPP) which is involved in farsenylation of cell membrane proteins. The inhibition of FPP may cause a reduced effect of PDT on cell rescue. The treatment with bisphosphonates seems to have a synergistic effect with PDT treatment. As such, light dosimetry in PDT treatment may need to take into account potential therapeutic interactions between PDT and current medical therapies in the treatment of skeletal metastatic burden.

M.K. Akens B. B. Yang A. J. Yee

Versican is a large extracellular proteoglycan that is expressed in a variety of tissues and primary malignancies including infiltrating breast carcinoma. It also appears that versican can inhibit intercellular adhesion of normal as well as malignant cells. With the observation of selectin-like properties of versican G3 the investigators hypothesise that versican G3 influences not only local tumour invasiveness but also systemic metastases including the spread to bony sites. The present study aimed to test the hypothesis of versican G3 associated metastatic invasiveness in a murine osteolytic metastatic model of human breast carcinoma.

Human carcinoma cells (MT-1), transfected with the either a versican-G3-construct (n=7) or a vector-control (n=8) gene, were injected intracardically female athymic rats. The rats were examined clinically at serial time-points following injection and animal weight recorded. Animals were euthanised three weeks after tumour cell injection. On digital lateral radiographs of the scapula osteolytic areas were measured. Additionally, histomorphometry was performed on sections stained with human EGFr antibody to evaluate tumour burden within rodent vertebrae. Statistical analyses were performed using one way ANOVA.

All rats demonstrated weight loss approximately three weeks following tumour cell injection. However, the extent of weight loss observed over time was greater for the versicanG3 group (p< 0.05). Osteolytic metastases were observed using fine detail radiography at the day of euthanasia. Osteolytic burden was greater (p < 0.002) in the G3 transfected group (34.7 %; lytic area scapula) when compared to vector-control animals (8 %).

Versican G3 domain appears to influence the development of metastases to bone and soft tissue. The propensity of versican G3 to influence tumour invasion to bone and the mechanisms of versican G3 mediated osteolysis warrants ongoing study. With the known interactions between versican G3 and beta1 integrin in other cancer cell types and the increasing knowledge regarding several beta3 integrin-expressing cell populations, including osteoclasts in breast cancer tumour progression, the potential interaction between versican G3 and integrin receptors in bone may influence tumour mediating chemotactic and haptotactic migration towards bone factors.

F. Mwale J. Antoniou O.L. Huk G. Marguier A. Petit D.J. Zukor

Although the etiology of low back pain is unclear, it is believed that intervertebral disc (IVD) degeneration plays a major role. In the present study, we sought to determine if bovine IVD cells maintain their phenotype in a mouse subcutaneous injection model, while embedded or not in biocompatible matrices.

Nucleus pulposus (NP) cells were isolated from adult bovine tails. Ten million cells were resuspended either in 500 ƒÝl of DMEM or in a negatively (alginate) or positively (chitosan) charged matrix. The mixtures were then injected subcutaneously in Balc/c nude mice. After two weeks, the mice were sacrificed and the implants harvested. The implants were examined histologically with a hematoxylin and eosin stain. The implant size was measured and the cells were counted. Proteoglycan was assessed by the GAG assay. The expression of type I and II collagens, aggrecan, and CD24 genes was analyzed by reverse transcription ¡V polymerase chain reaction (RT-PCR).

Histologic evaluation confirms the presence of cells in all NP implants. The presence of alginate increased the implant size, the number of cells in the implants, and to a lesser extent, the proteoglycan content, compared to implants formed with cells injected alone. However, chitosan had no effect on the implant size, the number of cells and the aggrecan content. NP implants expressed the same pattern of genes as the native NP tissue (i.e. type I and II collagens, aggrecan, and CD24). The presence of alginate did not affect this expression pattern whereas chitosan decreased slightly their expression.

After injection in mice, bovine NP cells appeared to retain their native phenotype. The RT-PCR analysis revealed that NP cells expressed aggrecan, type I and type II collagens as well as CD24, a specific marker for the NP phenotype. Also, NP cells can be embedded in matrices to produce NP-like features in vivo. In conclusion, we have developed a simple mouse subcutaneous injection model that recreates the features of the native IVD and avoids the need to use a disc degeneration model.

M.R. Hardisty I. Sigal T. Skrinskas C. M. Whyne

To compare strains measured in a whole rat-tail vertebra by image registration (IM) with those predicted by solid finite element analysis (FEA). Quantification of bone strain allows better understand fracture risk, bone healing and turnover.

The sixth caudal vertebra of an rnu/rnu rat was μCT scanned (17.5×17.5×17.5μm/voxel) while loaded (27N axial compression) and unloaded. IM was used to calculate strain and displacement fields in the bone due to the applied load by finding a spatial mapping between the two scans. Strain was resolved to varying spatial resolution; high strain gradient regions (ie growth plates) were analyzed to higher spatial resolutions. A FE model was created of the unloaded vertebra, consisting of tetrahedral elements with transversely isotropic material properties. Elements were assigned elastic moduli based upon μCT image intensities. Growth plate moduli ranged from 0–150kPa and the bone moduli ranged from 0.2–15000MPa. Vertebral geometry was created through segmentation of μCT images. Displacement boundary conditions were obtained by matching cranial and caudal surfaces in the unloaded and loaded scans. The displacement fields of the two methods were compared by using the fields calculated to deform the unloaded scan to match the loaded scan. The strains were compared by plotting FEA measured axial strain against IM calculated axial strain.

The displacement fields calculated by both methods were able to spatially align the unloaded scan to the loaded scan (Mean Voxel Intensity Difference: FEA=441HU, IM=328HU, Unregistered=969HU). IM and FEA show very limited agreement in axial strain measurement (R2=0.388, Slope=0.75, X-Intercept=0.0037) although both calculated high axial strains in the growth plates and low axial strains in the trabecular and cortical bone. Good agreement was found in the mean axial strain measured by both methods (IM= −0.044, FEA=−0.037). IM was better able to deal with difficulties in quantifying bone strain due to the growth plate than FEA.

IM presents advantages over FEA in measuring strain in complex whole bone trabecular structures, however has lower spatial resolution than is possible with FEA.

J. Antoniou G. Beaudoin C. N. Demers T. Goswami F. Mwale J. C. Iatridis

Despite a relentless search for adequate and effective treatment, low back pain is one of the most prevalent and costly illness in today’s society. While disc degeneration has been implicated as a major etiologic component of low back pain, there has been relatively little study in developing an objective, accurate, non-invasive diagnostic tool in the detection and quantification of matrix changes in early disc degeneration. The aim of the present study was to establish the correlations between magnetic resonance (MR) parameters and the biochemical and mechanical properties of the nucleus pulposus (NP) undergoing targeted trypsin digestion and axial compression.

Three-disc segments from bovine tails were either unloaded or loaded (cyclic compression: 50N-300N-50N at 1 Hz for 16h) to evaluate the effect of compression loading and the interactive effects of trypsin treatment and mechanical loading. The MR examinations were carried out in a 1.5-Tesla whole-body Siemens Avanto System (Siemens AG, Germany). The frozen NP and annulus fibrosus (AF) tissue sections reserved for mechanical analysis were tested under confined compression; swelling pressure was calculated based on the increase in measured force throughout the initial dwell period. Total water, proteoglycan, collagen, and denatured collagen contents were also measured.

Results showed that loading had a significant effect on the MR properties (T1, T2, T1ñ, MTR, ADC) of both disc tissues. Loading had a greater effect on the MR parameters and biochemical composition of the NP than trypsin. In contrast, trypsin had a larger effect on the mechanical properties. Results also indicated that localised trypsin injection predominantly affected the NP. T1ñ was sensitive to loading and correlated with the water content of the NP and AF but not with their proteoglycan content.

Results support the concept that physiologic loading is an important confounder and that T1ñ is an essential parameter in efforts to develop quantitative MRI as a non-invasive diagnostic tool to detect and quantify matrix and material changes in early disc degeneration. Further studies are required to determine the potential of the T1ñ technique to be used as a non-invasive diagnostic tool of the biochemical and mechanical changes occurring in disc degeneration.

R. Holtby S. Misra H. Razmjou E. Maman

The purpose of this historical prospective study was to compare the pre and post-operative Quality of Life (QOL) outcomes twelve months post-operatively in patients with partial thickness rotator cuff tears.

Data of ninety-three consecutive patients diagnosed with Partial Thickness Tear (PTT) who had undergone decompression, acromioplasty, or repair were used to compare the outcome between patients with Articular Tears (AT) and Bursal Tears (BT). The QOL outcome measures included one disease specific outcome measure, the Western Ontario Rotator Cuff Index (WORC) and two shoulder specific measures, the American Shoulder & Elbow Surgeons standardised shoulder assessment form (ASES) and the Constant-Murley score. A statistical paired t-test (pre vs. twelve months) and an independent t-test analysis (Articular vs. Bursal) were conducted to examine the impact of the tear site.

Forty-four Articular and forty-nine Bursal tears (forty-eight females and forty-five males) were included in the analysis. The mean age was 55.5 (SD: 13) and 53.3 (SD: 12) for the AT and BT groups respectively. There was no statistically significant difference between the two groups in pre-operative QOL outcome scores. Both groups showed significant improvement in the above outcomes (p< 0.0001) one year following surgery. However, the AT group was significantly less improved than the BT group in the post-op ASES scores (p=0.04), Constant-Murley scores (p=0.006) and WORC (p=0.01).

The intent of this study was to compare the pre and post operative scores and rate of improvement in two groups of patients suffering from rotator cuff pathology at different sites. The results indicate that the quality of life improves significantly regardless of the tear site. The pattern of recovery however is different indicating that patients with Bursal tears show a higher degree of improvement in their functional measures. The findings suggest that two types of tears are different in their etiology and pathomechanics.

P.B. MacDonald P. Lapner J. Leiter R. Mascarenhas S. McRae

The purpose of this prospective randomised clinical trial is to examine the effect of acromioplasty on the outcome of arthroscopic rotator cuff repair.

Patients included individuals that were referred for assessment after six months of failed conservative management. Following informed consent patients were randomly assigned to receive arthroscopic rotator cuff repair with or without acromioplasty. The surgeon was not blinded to the type of procedure; however, the researcher who performed the follow-up evaluations and the patient was blinded to the surgical protocol. Subacromial decompression (acromioplasty) was performed with release of the coracoacromial ligament off the anterior undersurface of the acromion. The procedure for arthroscopic cuff repair without acromioplasty followed the protocol of arthroscopic cuff repair with acromioplasty, without division of the coracoacromial ligament or resection of the acromion. Both groups experienced the same post-operative rehabilitation protocol. Wound healing and active and passive range of motion were assessed and recorded at six to eight weeks post-operatively. Subsequent post-operative visits occurred at three, six, twelve, eighteen and twenty-four months and included documentation of patient range of motion, patient derived WORC scores (1) and complete ASES scores.

Preliminary results suggest, based on a one-tailed t-test, patients that receive a rotator cuff repair with acromioplasty demonstrate a statistically significant improvement (< 0.05) in Quality of Life, based on WORC and ASES scores, compared to the non-acromioplasty group. To date, three patients in the non-acromioplasty group required a revision surgery; two of these patients had a Type III acromion.

Arthroscopic rotator cuff repair with arthroscopic acromioplasty in the treatment of full thickness rotator cuff tears is recommended for patients with a Type III acromion.

R. Bicknell P. Boileau C. Chuinard A. B. El Fegoun

The purpose of this study was two-fold: 1) to examine perioperative prospective changes in pain, disability and psychosocial variables in ACL reconstructed recreational athletes over the pre-op to eight week post-op period. 2) to see what variables will predict greatest disability at eight weeks post-op.

All participants were recreational athletes at the time of their injuries who had patella-autograft procedure at the the Queen Elizabeth II Health Sciences Centre. Fifty-four patients (twenty-nine males; mean age = 25.4 years, SD = 8.08). Mean education was fourteen years (SD = 2.08), 32%(17) were married, 67%(36) single, and 1% was divorced. 94%(51) of the sample was Caucasian, 3%(2) Black, and 1% Asian. One quarter reported their ACL injury was due to sport-based contact, with non-contact sporting activity reported at 76%(41). All participants completed measures of pain, depression, pain catastrophizing, state anxiety pre-op, on days one and two following surgery and again at eight weeks post-op. Disability was assessed pre-op and eight weeks post-op.

Pain was varied across comparisons with preoperative pain increased twenty-four and forty-eight-hour post-op. Pain at forty-eight-hours postoperative was significantly higher than pain reported at eight-weeks post-op. Catastrophizing did not differ from the pre-op to twenty-four-hour post-op but did drop from twenty-four to forty-eight-hours and forty-eight-hours to eight-weeks post-op. Pre-op depression increased twenty-four-hour post-op, but not from twenty-four to forty-eight-hours and declined at eight-weeks. Anxiety increase pre-op to twenty-four-hours but not from twenty-four to forty-eight-hours but did drop from forty-eight-hours to eight-weeks.Disability did not change over time. Regression showed age or gender did not predict disability but forty-eight hour pain and catastrophizing did.

These data indicate that pain and psychological variables change over time of ACL recovery. Results suggest that pain and distress peek during acute post-op period. As well, post-op catastrophizing predicts disability at eight weeks post-op which may indicate that catastrophizing may be related to behaviours related to slower recovery following ACL reconstructive surgery.

R. Bicknell P. Boileau C. Chuinard N. Jacquot S. Parratte C. Trojani

The purpose of this study was to review the results of biceps tenodesis and biceps reinsertion in the treatment of type II SLAP lesions.

We conducted a retrospective cohort study of a continuous series of patients. Only isolated type II SLAP lesions were included: twenty-five cases from January 2000 to April 2004. Exclusion criteria included associated instability, rotator cuff rupture and previous shoulder surgery. Ten patients (ten men) with an average age of thirty-seven years (range, 19–57) had a reinsertion of the long head of the biceps tendon (LHB) to the labrum with two suture anchors. Fifteen patients (nine men and six women) with an average age of fifty-two years (range, 28–64) underwent biceps tenodesis in the bicipital groove. All patients were reviewed by an independent examiner.

In the reattachment group, the average follow-up was thirty-five months (range, 24–69); three patients underwent subsequent biceps tenodesis for persistent pain, three others were disappointed because of an inability to return to their previous level of sport, and the remaining four were very satisfied. The average Constant score improved from sixty-five to eighty-three points. In the tenodesis group, the average follow-up was thirty-four months (range, 24–68). No patient required revision surgery. Subjectively, one patient was disappointed (atypical residual pain), two were satisfied and twelve were very satisfied. All patients returned to their previous level of sports, and the average Constant score improved from fifty-nine to eighty-nine points.

The results of labral reattachment were disappointing in comparison to biceps tenodesis. Thus, arthroscopic biceps tenodesis can be considered as an effective alternative to reattachment in the treatment of isolated type II SLAP lesions. By moving the origin of the biceps to an extra-articular position, we eliminated the traction on the superior labrum and the source of pain; furthermore, range of motion and strength are unaltered allowing for a return to a pre-surgical level of activity.

R. Bicknell P. Boileau C. Chuinard N. Jacquot L. Neyton J. Richou

The purpose of this study is to report the results of arthroscopic Bankart repair following failed open treatment of anterior instability.

We performed a retrospective review of twenty-two patients with recurrent anterior shoulder instability (i.e. subluxations or dislocations, with or without pain) after open surgical stabilization. There were seventeen men and five women with an average age of thirty-one years (range, 15–65). The most recent interventions consisted of sixteen osseous transfers (twelve Latarjet and four Eden-Hybinette), three open Bankart repairs and three capsular shifts. The causes of failure were additional trauma in twelve patients and complications related to the bone-block in thirteen (poor position, fracture, pseudarthrosis or lysis). All patients were noted to have distension of the anterior-inferior capsular structures. Labral re-attachment and capsulo-ligamentous re-tensioning with suture anchors was performed in all cases with an additional rotator interval closure in four patients and an inferior capsular plication in twelve patients; the bone block screws were removed in eight patients.

At an average follow-up of forty-three months (range, twenty-four to seventy-two months), nineteen patients were evaluated by two independent observers. One patient had recurrent subluxation, and two patients had persistent apprehension. Anterior elevation was unchanged, and loss of external rotation (RE1) was 6°. Nine patients returned to sport at the same level; all patients returned to their previous occupations, including the six cases of work-related injury. Eighty-nine percent were satisfied or very satisfied; the subjective shoulder value (SSV) was 83% ± 23%; the Walch-Duplay, Rowe and UCLA scores were 85 ± 21, 81 ± 23 and 30 ± 7 points respectively. The number of previous interventions did not influence the results. Eight patients (42%) were still painful (six with light pain and two with moderate pain).

Arthroscopic revision of open anterior shoulder stabilization gives satisfactory results. The shoulders are both stable and functional. While the stability obtained with this approach is encouraging, our enthusiasm is tempered by some cases of persistent pain.

D. Legay M. Forbes M. Ripley

Patient outcomes for arthroscopic repairs rotator cuff repairs have been analyzed almost exclusively by means of a single post-operative follow-up date. The purpose of this study was to examine the results of arthroscopic repairs of large rotator cuff tears performed by a single surgeon, both serially and at a two-year endpoint following surgery.

Seventeen patients with retracted U-shaped tears involving the supraspinatus were repaired arthroscopically between June 2002 and October 2003 using marginal convergence suturing followed by tendon-to-bone fixation. Patients were assessed at six weeks, three months, six months, one year, and two years following surgery. Each assessment consisted of a medical history, physical examination, and the Western Ontario Rotator Cuff (WORC®) questionnaire. Evaluation at the two-year study endpoint also included range of motion measurements and a modified University of California Los Angeles (UCLA) scoring system.

During the follow-up period, the three-month average WORC score (63.1%) was the first statistically significant difference from the pre-operation mean of 40.7%. WORC scores peaked at six months post-op (75.5%), and plateaued after this date. The one- and two-year average WORC scores (74.2% and 69.5%, respectively) did not differ significantly from the peak score achieved after six months. At the final two-year follow-up, the average UCLA score was 27.1. Fourteen of seventeen patients (78%) were satisfied with their surgical outcome. When workers’ compensation claimants were excluded from the results, the average UCLA score was 32.0 and patient satisfaction was 100%. There was no significant difference in average range of motion between the surgically-repaired shoulder and the unaffected shoulder.

This study shows that shoulder function improved significantly by three months after arthroscopic rotator cuff surgery and plateaued at six months post-op as measured by the WORC index. There was no statistically significant change in WORC score after six months post-op.

H. Razmjou M. Aarabi R. Holtby M. Aarabi

There is an association between SLAP lesions and laxity of the shoulder. The relationship between rotator cuff disease and hypermobility has also been implied. The purpose of this case-control study was to assess the impact of rotator cuff and superior labral pathologies on degree of glenohumeral translation and range of motion of the shoulder in comparison with individuals with normal shoulders.

This study involved individuals with asymptomatic shoulders (control group), and individuals with Rotator Cuff (RC) and Superior Labral Anterior and Posterior (SLAP) pathologies who underwent a repair. Subjects were matched by age, gender and hand dominance side. To assess laxity, all subjects including the control group were examined under anesthesia. The degree of humeral head translation was recorded in three (anterior, posterior and inferior) directions. Range of motion was documented in five directions.

Forty-six females and forty-four males with RC pathology and twenty-seven men with SLAP pathology were compared with the age and gender matched control group. The number of women with SLAP pathology was not sufficient for analysis. Rotator cuff pathology reduced range of motion of the affected side in all directions including flexion, elevation in scapular plane, internal rotation at ninety degrees of abduction and external rotation at zero and ninety degrees of abduction (p=0.02 to p< 0.001) as compared to normal population. Men with SLAP pathology had reduced range of motion in all directions (p< 0.001) except external rotation at ninety degrees of abduction. There were no statistically significant differences in glenohumeral glides between the normal group and SLAP group. However, the affected side of the patients with RC pathology had less laxity than normal population in anterior and posterior directions.

Presence of rotator cuff and superior labral pathologies affect biomechanics and consequently range of motion and accessory movements of the glenohumeral joint. We were unable to confirm a positive relationship between laxity and SLAP and RC pathologies. Prolonged disuse of the shoulder in these pathologies might have played a role in our findings.

J.C. Macdermid G. Athwal D. Drosdowech K. Faber

This study evaluated the impact of surgical wait-list times on the functional status and productivity of patients with rotator cuff tear

Two hundred and five patients were evaluated by a blind evaluator and by self report when referred for surgical management of cuff tear (confirmed by ultrasound or MRI). Patients were assessed on a monthly basis prior to surgery (two year limit). ROM and strength were assessed by an independent evaluator; patient’s self-reported comorbidity, functional status (WORC, SST), work limitations (WLQ-26) and work lost-time. Changes in health status were assessed using repeated measures ANOVA and GLM.

The mean age of the population used was 56+/−11 years in which 74% were males and 26% females. Tear size was distributed amongst this population as small (0–1 cm {45%), moderate (1–3cm 27%), large (3–5cm 23.2%) and massive (5+cm 15%). Patients had symptoms or an average of fourteen months prior to referral. Despite this, decline in strength (p mental demands) (output demands > time management demands). Loss in productivity exceeded 15%.

Rotator cuff tear causes substantial at work-limitation and work lost time. Patients lost strength and declined in functional status while waiting for surgical repair of a torn rotator cuff. The burden of illness, while waiting for cuff repair its substantial.

B.J. Shore G. S Athwal D. S Drosdowech K. J. Faber J. A. Johnston A. E. Kedgley

Rotator cuff tears are a common cause of shoulder pain and dysfunction. Therefore, the purpose of this in-vitro biomechanical study was conducted to determine the effects of simulated tears and subsequent repairs of the rotator cuff tendons on joint kinematics.

Eight paired fresh-frozen cadaveric shoulder specimens (mean age: 66.0 ± 8.7 years) were tested using a custom loading apparatus designed to simulate unconstrained motion of the humerus. Cables were sutured to the rotator cuff tendons and the deltoid. Loads were applied to the cables based on variable ratios of electromyographic (EMG) data and average physiological cross-sectional area (pCSA) of the muscles. An electromagnetic tracking device (Flock of Birds, Ascension Technologies, VT) was used to provide real-time feedback of abduction angle, to which the loading ratio was varied correspondingly. 2 and 4cm tears were made starting at the rotator cuff interval and extending posteriorly. Specimens were randomised to receive either single or double suture anchor repair. In order to quantify repeatability, five successive tests on each of the intact, torn, and repaired cases were performed. Statistical significance was established using One- and Two-way Repeated Measured ANOVAs (p< 0.05).

Rotator cuff tears caused alteration in glenohumeral kinematics. A 2cm tear caused the humerus to consistently move posterior through the arc of abduction; however, as the tear increased to 4cm the humerus moved anteriorly, returning towards the intact state. Double row suture anchor repairs more accurately reproduced the kinematics of the intact specimen compared to single row suture anchor repair.

The initial posterior displacement in the plane of elevation with the sectioning of the supraspinatus is related to the diminished anterior moment on the glenohumeral joint. As the tear proceeds into the infraspinatus, the anterior and posterior forces become more balanced and a return to near normal intact kinematics was observed. This study demonstrates that double row suture anchor repair more accurately reproduces active shoulder kinematics of the intact shoulder specimens.

J. Anderson D.S. Drosdowech K.J. Faber J.C. MacDermid

This study evaluated the impact of smoking on the surgical outcome of rotator cuff repair controlling for age, gender, and size of tear.

Two hundred and fifty patients were evaluated by a blind evaluator and by self report (SST and WORC questionnaires) at baseline and one year post-op. Types of cuff repair included arthroscopic, mini-open and open procedures. Smoking status was evaluated as a current smoker, quit, or never smoked. Smoking history was subsequently dichotomised into smoker and non-smoker. Generalised linear modeling was used to determine the impact of smoking on surgical outcome using age, gender, and tear size as covariates.

The mean age of the population used was 56+/−11 years in which 70% were males and 30% females. Tear size was distributed amongst this population as small (0–1 cm {44.9%}), moderate (1–3cm {22.7%}), large (3–5cm {15.2%}) and massive (5+cm {17.2%}). All preliminary analyses indicated gender affected tear size and surgical outcomes, and was also associated with smoking status. Due to this confounding effect, males and females were separated for subsequent analysis. The SST questionnaire found smoking to have a significant negative effect on the 1-year l outcomes of males (8.5 vs. 6.1 p=0.025). A similar trend was seen with the WORC (p=0.07). No significant effects were seen for females, but the sample size was underpowered.

Analysis of this population of rotator cuff repairs showed complex interrelationships may exist between gender, age, physical demands and smoking status. The existence of these confounding interrelationships may explain the mixed results seen in the literature concerning smoking and orthopedic procedures. This relatively large cohort established a negative impact of smoking on outcome, after controlling for covariates and confounders. Future research on mediators of cuff outcome should consider potential confounders. Conclusion: Smoking negatively effected surgical outcomes for males but was inconclusive for females. Sex behaved as a confounding variable that masked the smoking effects.

D.S. Drosdowech K. Iosipchuck J. MacDermid

Hemiarthroplasty has been accepted as a viable alternative in the treatment of painful arthritis due to massive rotator cuff failure in patients with well-preserved functional active forward elevation of the shoulder. Unfortunatley, the early clinical results and long-term durability of hemiarthroplasty for rotator cuff tear arthropathy (RCTA) have been inferior to those seen in other disorders, most notably concentric osteoarthritis. Concern regarding the potential need for revision to a reverse shoulder arthroplasty has given rise to the notion of a resurfacing prosthesis as a primary procedure rather than a traditional stemmed-hemiarthroplasty in the hopes of reducing procedural and postoperative complications.

Eleven resurfacing humeral arthroplasties (Global CAP, Depuy) were performed for RCTA as a primary arthroplasty. There were six males and five females, average age of 74.7 years. 36% had undergone previous surgery on the affected side. All had failed a minimum of one year of non-operative treatment prior to surgery. Follow-up averaged eight months (range 4–12).

Prospective mean data analysis showed an improvement in all scales from preoperative baseline levels inclusive of the SST (3.5–6), ASES assessment form (8–17.5), Constant score (49–79) and the DASH (50–27). Mean active forward elevation remained relatively unchanged (one hundred and nine to one hundred degrees), while mean active external rotation improved (thirty-three to fifty-four degrees). Mean computerised muscle testing showed improvement in both elevation (5.1–7.7 N/m) and external rotation strength (2.6–5 N/m). Radiographic analysis has not shown any evidence of implant loosening to date.

Resurfacing humeral arthroplasty seems to demonstrate early favorable clinical results in this group of patients with RCTA. This may serve as an alternative to a stemmed-hemiarthroplasty in these patients and possibly result in a less complicated revision to a reverse prosthesis in the future should this be deemed necessary. Given these results are early, ongoing clincal followup will be necessary to define the longer-term durability of this procedure.

N. Mahomed

Aim of the study: to determine if WOMAC pain and function outcomes and patient satisfaction are maintained after the institution of a new standardised care pathway for people undergoing primary hip or knee replacement (TJA).

Twenty-three institutions partnered to design and implement a care pathway to provide a seamless transition from acute to rehabilitation sectors by pre-surgery streaming of patients to inpatient or home-LOS were tracked against bench marks of minimum 50% discharged home and an inpatient rehab stay of seven days. Subjects were recruited to the evaluation pre-surgery completing the WOMAC. Follow-up WOMAC and satisfaction questionnaires were completed three months later. The sample of five hundred ensured that the 99% confidence interval (CI) of the mean for each of WOMAC pain and function would be within two and five points respectively of the results of a randomised trial where TJA patients received home-based or inpatient rehabilitation.

On average greater than 50% of people were discharged home from acute care and over 50% of those individuals receiving inpatient rehab were discharged in seven days, with 80% discharged by day ten. 349 (73%) of those accrued (mean age 69 222 females) completed three month follow-up Those discharged home have mean pain and physical scores of 82.7 and 78.7% (where high scores are better pain relief and function) and those receiving inpatient rehab have pain and function scores of 78.6 and 72.4%. These values are within our a priori CI for outcome. 13% reported dissatisfaction with rehabilitation planning and care.

This model of care has achieved the goals of increasing the proportion of people discharged home following TJA and decreased rehabilitation LOS with increased system capacity for rehabilitation. The patient outcomes are maintained.

R. B. Bourne C. K. Anderson B. M. Chesworth L. E. Hornick G. S. Zaric

The purpose of this study was to establish a model to predict the future need for total hip and knee replacement surgery over the next ten years.

Analysis based on queuing theory and Ontario data (Ontario Joint Replacement Registry) considered such factors as changing demographics, specific wait time objectives and changing indicators to predict the future need for THR and TKR up to 2015.

26 725 Ontarians were waiting for THR and TKR surgery on any given day in 2004–05. Each month, the number of new decisions for surgery exceeded the actual number of surgeries by over 20%, adding another five hundred patients to the wait list. We predict that the population > fifty-five years of age will increase by 3.4% annually and that the willingness of patients to consider TJR surgery will increase by 8.7%/year To reduce wait times and establish a steady state of waiting (less than 6 months wait), more than 50 000 surgeries per year must be provided within five years and 70 000 total joint replacements per year by 2014–15 as compared to the 31 448 performed annually at this time. Providing this volume of surgeries means that the number of surgeons will have to double within five to seven years.

The results of this queuing theory analysis predict a substantial need for markedly increased THR and TKR volumes and orthopaedic manpower over the next decade.

M. Lavigne P.A. Vendittoli R.B. Siva Rama

Heterotopic ossification (HO) occurs commonly after total hip arthroplasty (THA). Its severe form can result in impaired range of motion with reduced functional outcome. The rate and severity of HO after hip surface replacement arthroplasty (SRA) have never been well studied.

Two hundred and ten hips were randomised to receive uncemented metal-on-metal THA or metal-on-metal SRA. Standard radiographs of the pelvis were assessed for HO by two reviewers at the latest follow-up (minimum of six months), using Brooker severity grading and Kjaersgaard-Andersen regional classification.

The incidence of HO was 38.5% in the SRA group compared to 32.6% in the THA group (p=0.5). However, there was a significant difference in severity grades for the two groups (chi square, p=0.02). According to Brooker’s classification, nearly half of HO was of grade two in SRA and of grade one in THA. SRA was associated with significantly higher rates of severe HO (grades three and four) than THA (12.5% vs. 2.2%; p=0.009). Inter-rater agreement for Brooker grading was excellent (Cohen’s kappa, 0.88; p< 0.01).

The incidence of HO after hip arthroplasty seems to be determined by patient-related factors. However, HO severity appears to be associated with local surgical factors and thereby SRA may result in more severe HO than THA. An extensive surgical approach, additional soft tissue release and the blunt damage occurring in gluteal muscles with SRA may signal the induction of more severe HO. Peri-operative deposition of bone debris derived from femoral head preparation may also play a role by transplanting osteoprogenitor cells. Surgeons must be aware of this risk of severe HO when offering SRA as an alternative treatment to younger patients. Routine prophylaxis with NSAIDs needs to be considered in these patients. A meticulous surgical technique to reduce muscle damage, pulsed lavage to clear bone debris, and debridement of necrotic tissue, may help to decrease the risk of severe HO in SRA.

R. Bicknell P. Boileau C. Chuinard

The purpose of this study was to evaluate outcome following arthroscopic biceps tenotomy or tenodesis for massive irreparable rotator cuff tears associated with biceps lesions.

This is a retrospective study of sixty-eight consecutive patients (mean age 68 ± 6 years) with seventy-two irreparable rotator cuff tears treated with arthroscopic biceps tenotomy (thirty-nine cases) or tenodesis (thirty-three cases). All patients were evaluated clinically and radiographically at a mean follow-up of thirty-five months (range, 24–52).

Fifty-three patients (78%) were satisfied. Constant score improved from forty-six to sixty-seven points (p< 0.001). Presence of a healthy, intact teres minor on preoperative imaging correlated with increased postoperative external rotation (40 vs. 18°, p< 0.05) and higher Constant score (p< 0.05). Three patients with a pseudoparalyzed shoulder did not benefit from the procedure and did not regain active elevation above the horizontal level. By contrast, fifteen patients with painful loss of active elevation recovered active elevation. The acromiohumeral distance decreased 1 mm on average, and only one patient developed glenohumeral osteoarthritis. There was no difference between tenotomy and tenodesis (Constant Score sixty-one vs. seventy-three). A “Popeye” sign was clinically apparent in twenty-four tenotomy patients (61%), but none were bothered by it. Two patients required reoperation with a reverse prosthesis.

Arthroscopic biceps tenotomy and tenodesis effectively treats severe pain or dysfunction caused by an irreparable rotator cuff tear associated with biceps pathology. Shoulder function is significantly lower if the teres minor is atrophic or fatty infiltrated. Pseudoparalysis or severe cuff arthropathy are contraindications.

G. Lim D. Backstein P. Boscainos A. E. Gross O. Safir

The purpose of this study was to ascertain the radiographic results of the modified extended trochanteric sliding osteotomy (ETSO), performed by the senior author. The main feature of the ETSO is preservation of the posterior 1cm of greater trochanter and its attached external rotators. Results with this particular osteotomy for revision hip arthroplasty have not been previously reported.

We reviewed forty-eight ETSOs in forty-six patients that underwent revision hip arthroplasty from March 2000 to March 2006. Nineteen osteotomies were for femoral revision alone, and twenty-nine osteotomies were performed for femoral and acetabular revision. All but six (12.5%) had cortical strut augmentation of the osteotomy. The length of the osteotomy, the length of distal fit, the number of wires used were recorded and their relation to union of the osteotomy and femoral stem loosening were investigated.

The rate of ETSO union in this study was 91.3%. Four osteotomies were not united and this was associated with femoral stem subsidence and loosening requiring femoral stem revision in three cases. The rate of femoral stem loosening requiring revision was 8.3%. The length of the osteotomy did not correlate with femoral stem loosening, but a distal fit of less than 9cm was highly significant(p=0.001) with regards to loosening. The use of cortical struts was not protective against osteotomy non-union or femoral stem loosening. Osteotomy union was shown to be dependant on a well fixed (p< 0.0001) and stable stem (p< 0.0001). Three patients dislocated postoperatively (6.5%), and only one of these required revision surgery.

The modified extended trochanteric osteotomy has a low rate of dislocation and a reliable rate of union. We have shown that a well fixed and stable stem is critical to successfully obtaining union of the osteotomy.

T. Kostamo C.P. Duncan D.S. Garbuz B.A. Masri G. Biring

We report the outcomes ten to fifteen years after two stage revision for hip infection in one hundred and three patients.

All patients or their next of kin were contacted to determine their current functional status and whether they had required repeat surgery or had recurrent infection. The Oxford-12, SF-12, and WOMAC questionnaires were administered. A comprehensive chart review was undertaken to review the infective organisms, surgery, approach, complications, and need for further revision surgery.

Ten patients had re-infection, six of whom responded to repeat surgery with no further sequelae. Two patients required resection arthroplasty, one patient underwent hip disarticulation after eventual failure of treatment and bone loss, and one immunocompromised patient developed osteomyelitis and was subsequently lost to follow-up. Long-term success rate for two stage- revision is thus 90.3%, or 96.1% with additional surgery. Since then, three patients required revisions for aseptic loosening, one for recurrent dislocation. We were able to follow up forty-one patients, 85 % of whom provided health-related quality of life outcome scores. Thirty-nine patients were deceased, with their outcome confirmed via their last follow-up or with family members, for a total follow-up rate of 78 %. Twenty-three patients were lost to follow-up, but did not undergo further surgery or have reinfections treated at our centre.

Two-stage revision for hip infection, which includes an interim prosthesis of antibiotic loaded cement, offers a predictable and lasting solution for patients with this difficult problem.

T. Bell R. B. Bourne S. J. MacDonald R. W. McCalden D.D. R. Naudie F. Ralley

The purpose of this study was to evaluate the impact of dalteparin use on transfusion rates and blood loss in patients undergoing primary total joint arthroplasty at our center.

We prospectively studied the transfusion patterns of 1642 patients who underwent primary total hip or knee arthroplasty between January 2004 and December 2005 by five arthroplasty surgeons. The influence of daltaperin use, release of tourniquet in total knee arthroplasty, and the turnover of house staff were analyzed using SPSS V14.0 statistical software.

We identified seven hundred and three total hip and nine hundred and thirty-nine knee arthroplasty patients. The mean haemoglobin drop was statistically significant between 2004 and 2005 (p< 0.001). This was seen in both hip (p=0.014) and knee (p< 0.001) patients. Subgroup analysis of total knee arthroplasty revealed a significant difference in haemoglobin drop between surgeons who released the tourniquet prior to closure compared to release at the end of the case (p=0.005). In addition, there were significant monthly differences that corresponded with the turnover of house staff (p=0.039). Overall, no statistically significant increase in allogeneic transfusion rates was observed between years, months, and individual surgeons.

The use of dalteparin was found to be associated with a significantly increased haemoglobin drop in primary total joint replacement when compared to warfarin. However, the use of dalteparin was not associated with an increase in allogeneic transfusions at our center. The results also suggest that there may be an advantage to releasing the tourniquet and achieving hemostasis prior to closure in knee arthroplasty. Finally, the results emphasise the importance of educating new house staff on methods to reduce intra-operative blood loss and transfusion rates.

G. Wood A. Kapoor A. Javed

The use of wound drains in arthroplasty patients is controversial. Previous work including a meta analysis looking at closed drainage systems has shown no benefit in their use. It is postulated that retransfusion drains may offer an advantage over closed drains and cut allogenic transfusion requirements and aid wound healing. This study was designed to assess the use of retransfusion drains in hip and knee replacement patients and prove the null hypothesis that there is no difference in post op haemaglobin levels or transfusion with their use.

Following an initial pilot audit of blood drainage in such patients we designed a protocol for a prospective trial. In a prospective randomised controlled study we evaluated the use of retransfusion drains in primary hip and knee arthroplasty patients. Eighty patients were randomised to removal of the drain at six or twenty-four hours post op, to assess the most efficient and beneficial use of such drains. The rate of blood drainage, post-operative haemaglobin (Hb) levels, blood transfusion, hospital stay, complications and rehabilitation observed. The two groups were comparable, have a follow up of two years and all attempts to control variables were made.

The drop in haemaglobin, hospital stay, complications and rehabilitation between both groups revealed no significant difference in all respects. Wound healing appeared better in six-hour group for hip and knee patients. There is no effect of type of joint or age on the drop in Hb. The TKR patients drained sig. more blood than the THR patients. The rate of blood loss is discussed. The amount of blood drained that was retransfused was 94% efficient. The allogenic transfusion rates were higher in the six-hour knee group. Three patients required post operative antibiotic but at latest follow up all patients were reported as having no problems and no evidence of infection.

This study concludes that retransfusion drains offer no advantage in the arthroplasty patients’ care.

J. Cummins S. Finlayson S. Kantor I. Tomek

Antibiotic-impregnated bone cement (ABC) is infrequently used in the North America for primary total hip arthroplasty (THA) due to concerns with cost, performance, and the possible development of antibiotic resistance. The purpose of this study is to examine the cost-effectiveness of using ABC in primary THA for osteoarthritis compared to the use of cement without antibiotics.

A Markov decision model was used to determine if ABC is a cost-effective strategy for primary THA in patients with osteoarthritis. The model tabulates costs and quality adjusted life years (QALYs) accumulated by each patient to evaluate the cost-effectiveness of each strategy. Rates of revision for infection and aseptic loosening were estimated from the Norwegian Arthroplasty Register, and were used to determine the probability of transitioning to a revision arthroplasty for either infection or aseptic loosening. The model was also used to evaluate the cost-effectiveness of ABC when only revisions for infection are considered. Peri-operative mortality rates, utilities, and disutilities were estimated from the arthroplasty literature. Costs were also estimated from the literature using in-hospital resource use as the method of measurement for primary THA. The additional cost of using ABC ($600) was then added to the average cost of the initial procedure ($21,654).

ABC is less expensive and more effective than standard cement when all revisions are considered, making the use of ABC the dominant strategy. When only revision for infection is considered, the use of ABC has an incremental cost-effectiveness ratio (ICER) of $37.335 per QALY compared to cement without antibiotics – which compares favorably with the cost-effectiveness of accepted medical procedures. Sensitivity analyses reveal that for all revisions the additional cost of ABC would need to be greater than $1500, or the average age of patients undergoing primary THA would need to be greater than eighty-three before the use of ABC would cost more than $50,000 per QALY gained. When only revision for infection is considered, the additional cost of ABC would need to exceed $650 before the cost of ABC would exceed $50,000 per QALY gained.

Use of ABC for primary THA is cost-effective over a wide range of assumptions. Notably, when all revisions are considered, ABC is less costly and more effective than use of standard cement over the life span of the patients.

M. Lavigne N. Nuno D. Plamondon P. A. Vendittoli R. Winzenrieth

To compare the volume of acetabular bone resection after primary hip arthroplasty with different cup designs and technique of implantation using a computer model.

The factors influencing acetabular bone resection during acetabular cup implantation in THA or hip resurfacing (SRA) include the design of the component and technique of implantation. The impact of these variables on bone resection was simulated with a computer model. A 3-D pelvis was reconstructed from CT scan images. The bony acetabulum circumference was 52.5mm. Implantation of pressfit acetabular component sustaining angles of 165°, 170° and 180° with different wall thicknesses (3.5, 4.0, 5.0mm) at various depths was simulated.

Bone loss of 2742mm3 was calculated for the 165°, 4mm thick, 54mm cup, and deepening of reaming by 1 and 2mm would result in bone loss of 3780mm3 (+38%) and 5076mm3 (+85%), respectively. When oversizing to a 56mm 165° component, 4998mm3 (+82%) of bone was removed. For a 54mm, 5 mm thick component sustaining an angle of 180°, the bone loss would reach 12 410mm3 (+450%).

Acetabular component design has a significant influence on the amount of acetabular bone resection. The surgical technique (avoiding over deepening and oversised components) should minimise bone loss. This knowledge is of particular importance in hip resurfacing since the acetabular component size depends on the selected femoral component size. The knowledge is is also important in THA to minimise bone loss at primary implantation.

D. Simon P. Beaule W. Castle R. Feibel P. Kim

Cementless femoral fixation is the gold standard in revision hip arthroplasty. Distal fixation is achieved using either a cobalt chrome or titanium stem. The purpose of this study is to report the long-term survivorship and clinical outcome of a titanium, long-stemmed, load-bearing calcar-replacement femoral component from an independent centre.

Eighty-one patients (average seventy-four years, range thirty-five to ninety-one) underwent hip arthroplasty with the Mallory-Head calcar-replacement femoral component, by a single surgeon. There were thirty-eight males and forty-three females with fifty-four hips initially revised for aseptic loosening, thirteen for peri-prosthetic fracture, and five for infection as a two-stage procedure. The implant was used as a primary device in eight patients with deformed proximal femurs. At most-recent follow-up, radiographic analysis was conducted and clinical outcome scoring was assessed using the SF-12, Harris Hip Score, and WOMAC questionnaire for surviving patients. Complications were also reviewed.

At a mean follow-up of 7.4 years (range four to fifteen), eight patients have died. There was one deep infection, three DVT’s, and two dislocations in the perioperative period. Six femoral stems have ultimately required another revision surgery for aseptic loosening, two for infection, and 1 for implant fracture at a mean of 5.6 years after initial revision. Four patients required removal of the proximal trochanteric bolt due to breakage or loosening. Overall survival of the implant at five years is 95% (CI 0.87–0.98) and 87% (CI 0.72–0.94) at ten years.

The clinical outcome of the Mallory-Head calcar-replacement femoral revision stem is reported from an independent centre. Although the results are encouraging, it would appear that proximal load-bearing fixation with the calcar-replacement stem is not as reliable as distal fixation. The use of a trochanteric bolt was associated with fracture of the greater trochanter or need for a separate surgical procedure for removal. For this series, there was an overall 11% failure rate at a mean follow-up of 7.4 years. The mechanical failure rate is 7.4%. Our overall and mechanical failure rates are somewhat higher than those of the implant developers, who reported 94% overall survival, and a 1.9% mechanical failure rate at a mean follow-up of eleven years.

N. Greidanus G. Biring C. Duncan D. Garbuz B. Masri

This single incision, anterolateral intermuscular approach (AL-IM) utilises the interval between gluteus medius and tensor fascia lata. The aims of the study were to compare the quality of life, satisfaction and complications of this approach with two of the most commonly used limited incision transmuscular (TM) approaches, namely the mini-posterior (P-TM) and the mini-direct lateral (L-TM).

One hundred and ninety-nine patients receiving MIS THA surgical procedures were evaluated prospectively (63 AL-IM, 68 P-TM and 68 L-TM). The outcome variables were WOMAC function, pain, stiffness, SF-12 (physical & mental), Oxford-12, satisfaction and radiological outcome. Parametric and non-parametric analyses were performed.

There were no significant differences between groups in baseline characteristics including age, sex, BMI, co-morbidity, or pre-op WOMAC, SF-12, Oxford-12 (p> 0.05). However, the AL-IM group was associated with superior outcomes (p< 0.05) in WOMAC function, WOMAC pain, global WOMAC, Oxford-12 and SF-12 physical component.

In the short term the AL-IM approach provides significant improvements in quality of life scores over other limited incision approaches. It provides minimal soft tissue disruption and maintains the abductor musculature and posterior soft tissue envelope, with similar complications and radiological outcomes.

A. Yee H. Ahn J. Braybrooke J. Finkelstein M. Ford A. Gallant

To evaluate the effect of wait time to surgery on patient derived generic and disease-specific functional outcome following lumbar surgery.

Study cohort of seventy patients undergoing elective posterior lumbar spinal surgery for degenerative conditions. Prospectively collected SF-36 and Oswestry Disability questionnaires administered preoperatively, six weeks, six months, one year postoperatively. Time intervals from onset of symptoms to initial consultation by family physician through investigations, spinal surgical consultation and time spent on the surgical waiting list to surgery quantified. Time intervals compared to patient-specific improvements in reported outcome following surgery using Cox-Regression analysis. The effect of patient and surgical parameters on wait time was evaluated using median time as a reference for patients with either a longer or shorter wait.

Patient follow-up completed in fifty-three (76%). Improvements in patient derived outcome were observed comparing post-operative to pre-operative baseline scores (p< 0.05). The greatest improvements were observed in aspects relating to physical function and pain. A longer wait to surgery was associated with less improvement in surgical outcome (p< 0.05, SF-36 domains BP, GH, RP, VT, and Physical Component Scores). The greatest impact observed was a prolonged surgical wait-list time on SF-36 PCS scores following surgery (Hazard’s ratio 3.53). Patients requiring spinal fusion had a longer wait when compared to those not requiring fusion (p< 0.05).

A longer wait time to spinal surgery can negatively influence surgical results as quantified by patient derived functional outcome measures. Surgery resulted in the greatest improvement in pain severity and physical aspects of function, however, these areas also appeared the most impacted by a longer wait to surgery.

A. Crawford S. Dagenais A. Gruszczynski E. K. Wai

Although many authors have emphasised the importance of lumbar spinal decompression surgery for “leg dominant pain”, there is little objective evidence on the outcomes of surgery for varying degrees of back pain compared to leg pain. Moreover, it is unclear whether patients with radicular or claudication type leg pain, presenting with significant back pain as well, would benefit from surgical decompression. This study evaluated the outcomes of patients with

(i.) leg dominant pain compared to patients with

(ii.) leg pain along with significant back pain.

A prospective cohort of consenting adult patients, who have consecutively undergone elective primary posterior lumbar decompression surgery at a single academic institution by sub-specialty spinal surgeons were evaluated with longitudinal follow-up using standardised outcomes instruments. The cohort was analyzed into those with

(i.) leg dominant pain and those with

(ii.) significant back pain relative to their leg pain based on pre-operative VAS scores.

Univariate and multivariate analyses were used to adjust for potential confounding effects of demographic, surgical, waiting list and psychosocial factors.

Of the eighty-five eligible patients, sixty-nine (81.3%) had at least one year follow-up with a mean follow-up time of seventeen months. Baseline factors were similar between the two groups except for back and leg pain and wait times for consultation after referral. Patients with significant back pain waited significantly longer (p = 0.04) for consultation after referral than those with leg dominant pain. Significantly (p = 0.002) more patients (93%) in the leg dominant pain group reported clinically significant improvement in the Oswestry than the significant back pain group (59%). This effect remained after multivariate adjustments for other baseline factors.

This study is one of the first to provide objective evidence to support the notion that the primary indication and best predictor of outcome for lumbar decompression surgery is leg dominant pain. Presence of significant back pain, despite presence of leg pain, is a strong predictor of poorer post-operative results. Further research is required to determine if the current long waiting lists are a causative factor for development of significant back pain in surgical candidates.

N. Aslim E. Schemitsch K. Tokunaga J. Waddell

The purpose of this study was to evaluate the effect of previous femoral osteotomy on the outcome of total hip replacement performed for degenerative arthritis secondary to developmental dysplasia of the hip.

Eighty three primary total hip arthroplasties were performed in sixty-nine patients with osteoarthritis secondary to developmental hip dysplasia (DDH) with a minimum three year follow up. Twenty six hips had undergone previous femoral osteotomy (eleven hips, femoral osteotomy alone (FO); fifteen hips, combined femoral and pelvic osteotomy and fifty-seven hips, no previous surgery. The non operative patients with DDH served as an age and sex matched control group (control). Cementless arthroplasty was performed in seventy-eight hips. The mean duration from femoral osteotomy to primary THA was 22.9 years. The mean follow up was 7.6 years (FO) and 7.2 years (control).

The overall revision rate was 15.4 % (FO) and 21.1 % in the Control group (p> 0.05). Twenty-one hips had one or more complications during or after surgery. The FO group had a higher femoral fracture rate (23.1%) compared to controls (10.5%) (p< 0.05). At latest mean follow-up (7.4 yrs (range, two to sixteen)), the mean Harris hip score was eighty-five (FO) and eighty-five (control group) (p> 0.05). The function and pain scores in the femoral osteotomy group were similar to the controls (p> 0.05). The requirement for bone grafting was similar and operative time significantly greater (FO) compared to controls. The frequency of radiolucent lines around the femoral component in the FO group (36%) was significantly higher than the control group (12.2%) (p< 0.05). Survival analysis was performed with the Kaplan-Meier method. At ten years, the survival of the acetabular component was 84.6%/73.6% and for the femoral component 92.2%/96% in the FO/control group.

Patients with a prior femoral osteotomy have no significant difference in functional outcome, overall complication rate or revision rate compared to controls. However, there is a significant increase in femoral fracture and operative time. Previous femoral osteotomy does not compromise the functional outcome of subsequent total hip arthroplasty.

A. Sethi S. Lee R. Vaidya

The purpose of this study was to investigate the efficacy and fusion rates of a unilateral pedicle screw construct supplemented with a translaminar screw in transforaminal lumbar interbody fusion (TLIF). The construct was used with an aim of providing suitable spine stiffness with minimal implant load for spinal fusion.

Nineteen consecutive patients who underwent single level TLIF were included in the study. All patients had posterior spinal instrumentation using a unilateral pedicle screw construct with a contralateral translaminar screw. Patients were assessed preoperatively and at two, six, twelve and twenty-four weeks following surgery and at the end of one and two years. At every visit Oswestry disability index score,Visual analogue scale for pain and a pain diagram were recorded. A radiographic exam was also conducted and CT scan was done if there was concern about fusion.

The average follow up was twenty-four months. There were twelve males and seven females with an average age of forty-eight years. All patients went on to clinical and radiographic union. Sixteen of nineteen patients had significant clinical improvement on VAS for pain, Oswestry scores and pain medication. Three patients had recurrence of radicular pain on the side of the TLIF leading to reexploration. In all three patients solid fusion was observed but scar tissue was evident and symptoms resolved following redecompression of the foramen.

The biomechanical competence of a construct is evidenced by successful fusion. With the advent of minimally invasive techniques to achieve spinal fusion the goal is to use minimal instrumentation without compromising on the final stiffness of the spine. The construct of unilateral pedicle screws supplemented with a trans-laminar screw led to fusion in all our cases. It requires lesser soft tissue dissection and the posterior implants are 56% cheaper.

R. Vaidya S. Bartol J. Carp A. Sethi S. Sethi

Spinal surgery in obese and morbidly obese patients can be challenging to the operating surgeon. One of the major problems is obtaining a good surgical access. We have used the synframe retractor system in patients undergoing spinal fusion and have found it especially useful in obese and morbidly obese patients. This study reports our experience.

Seventy-seven consecutive obese and morbidly obese patients that underwent spinal decompression and fusion were reviewed. Patient selection was based on BMI values. Those with a BMI of more than thirty were included in the study. There were thirty-eight females and twenty-five males with an age of twenty-one to eighty-one years. Patient charts were used to acquire information regarding age,weight,height,gender,time in surgery, procedure start and end time,and departure. Postoperative complications and length of hospital stay were also recorded. Anesthesia notes were used to determine ASA scores,number of preoperative morbidities,and intraoperative blood loss. The synframe was used on all the patients. It is a retractor system which consists of a ring placed around the surgical site. It is fixed to both sides of the operating table with arms. Using retractor blades, the ring allows 360 degree access to the surgical exposure from any side.

The set up tme for obese patients was 59.8 minutes and 73.5 minutes for morbidly obese patients. The surgical time and blood loss was only marginally higher in these two groups than in normal weighted patients. The average postoperative length of hospitalisation was 5.8 days. The surgical incision length averaged 7.8 cms for single level and 11.5 for two level fusions. 44% patients suffered a complication. These included cage migration due to a fall, wound infection, dural leak,pulmonary embolism, deep vein thrombosis etc. No significant weight loss was recorded following the surgery.

Obese patients are a surgical challenge due to the comorbidities and difficulty in positioning and gaining good surgical access. The use of synframe retractor system improves surgical access, thereby reducing surgical time and blood loss. The surgical incision length was also comparable to normal weighted patients using this system. No significant weight loss was recorded following surgery. The high complication rate can be attributed to the associated comorbidities.

A. Athiviraham C. Scott D. Soboleski D. Yen

Although previous studies have shown poor correlation between clinical symptoms due to lumbar stenois and radiologic stenosis, no study has corrected for congenital variation in vertebral body size among individuals. This purpose of this study is to determine the relationship between the degree of radiographic lumbar spinal stenosis, adjusted with an internal control for vertebral body size, and disability from lumbar stenosis.

One hundred and twenty-three consecutive patients with clinical and radiologic confirmation of neural impingement secondary to lumbar stenosis were enrolled prospectively. Thecal sac AP diameter (TSD) and cross sectional area (CSA), and vertebral body AP dimension (VBD) were determined. These parameters were then correlated with patients’ symptoms using the modified Roland-Morris Questionnaire (RMQ) disability score.

This study found no statistically significant inverse correlation between TSD and RMQ score (p=0.433) or CSA and RMQ Score (p=0.124). In addition, there was no significant inverse correlation between CSA/VBD ratio and RMQ score (p=0.036) or TSD/VBD ratio and RMQ score (p=0.109). There was a significant difference in mean RMQ scores when the patients were divided into those with CSA greater than or equal to 70 mm2 and those less than 70 mm2, with T=−2.104 and p=0.038.

The degree of radiographic lumbar spinal stenosis, even with the use of an internal control of vertebral body size and standardized disability questionnaires, does not correlate with clinical symptoms. However, patients with more severe stenosis below a cross-sectional area critical threshold of 70mm2, have significantly greater functional disability.

S. S. Bederman J. A. Finkelstein M. Ford H. J. Kreder I. Weller A. J.M. Yee

As the population ages, the prevalence of degenerative spinal conditions is estimated to increase. With soaring healthcare costs, we must be vigilant in our accountability for proper resource allocation to ensure universal access. Significant recent increases in lumbar fusion rates have been observed in the US. Less is known regarding the Canadian experience. Our objective was to evaluate recent trends in lumbar fusion and determine how surgeon factors influence reoperation for spinal stenosis (SS) surgery.

Longitudinal follow-up study of lumbar surgical procedures for SS using administrative databases. Data was gathered on patient-hospital encounters from April 1, 1995 to December 31, 2001. We analyzed trends in spinal fusion. Index procedures (decompressions or fusions) and surgeon variables, such as specialty (orthopaedics, neurosurgery) and volume (above or below thirty cases/year), were selected as predictors of patient reoperation for SS. Adjustments were made for age, gender, and comorbidity. Reoperation rates were evaluated at six weeks, one and two years and until maximal follow-up.

6128 patients were identified (4200 decompressions and 1928 fusions). Proportionally more fusions were performed over the study period when compared to decompressions (1:2.6 in 1995 versus 1:1.5 in 2001). Orthopaedic specialty and higher surgical volume were associated with increased proportion of fusions (p< 0.0001). Reoperation rate was higher for decompressions at two years (OR 1.4) but not at long-term follow-up to ten years. Surgeon specialty had no impact on reoperation rates. Lower surgical volume demonstrated a higher reoperation rate after adjusting for specialty (Hazard Ratio 1.28).

Rates of lumbar spinal fusion have been increasing in Ontario, but at a lesser rate compared with the US. There is wide variation in surgical procedures between surgeon specialty and volume. Surgeon specialty had little impact on reoperation rates. Better long-term survival was observed in spinal surgeons with volumes over thirty cases per year after adjusting for surgeon specialty. Due to increasing rates of spinal fusion, the benefit of improved long-term survival in SS surgery with higher volume surgeons requires more detailed analysis before policy recommendations can be made.

E.K. Wai R. Dent H. Dornan A. Gruszczynski L. Vexler

Weight loss is commonly recommended as a treatment for back pain. However, there is little literature to support this. A recent systematic review has identified only studies relating to bariatric surgery. There are no other studies that address whether weight loss improves back pain.

Forty-five consecutive consenting patients were recruited following enrolment in a tertiary multidisciplinary weight management program. These patients were referred primarily for treatment of obesity. The program consisted of consultation and on-going supervision by a sub-specialty weight management physician, and group and individual sessions addressing diet, exercise and behaviour modification. Patients were assessed by independent observers prior to start of program and at twelve weeks into the program with standardised and validated outcomes tools measuring baseline factors, back pain and related functional disability at twelve weeks follow-up.

Prior to starting the program, forty-two patients (93%) reported some degree of low back pain of which 40% rated their pain as moderate (n = 12) or severe (n = 6). Using the Oswestry Low Back Pain Disability Index, 73% patients reported moderate (n = 18) or severe disability (n = 15). At twelve weeks, thirty-seven (82%) patients were available for assessment. There were significant improvement in VAS pain scores (mean change = 1.5, 95% CI: 0.7 to 2.4) and in Oswestry Low Back Disability Index (mean change= 8.6, 95% CI: 3.9 to 13.2). There were significant reductions in the prevalence of moderate or severe back pain (p = 0.04) and moderate or severe disability (p = 0.007) in the entire group.

This is the first study to provide empirical evidence on the positive effects of a weight loss program on back pain. These results lay the groundwork for longer follow-up and comparative studies.

E.K. Wai

The wait times between referral and initial consultation for a spinal surgeon are amongst the highest in the country. Moreover, the vast majority of patients seen by spinal surgeons are not considered appropriate surgical candidates and hence do not benefit from the surgeon’s expertise in surgical management. Identifying inappropriate patients as a method of “triage” may help reduce the wait times. This paper examines two possible “triage” mechanisms – (i.) questionnaire and (ii.) screening by an acute spine pain centre.

Phase I identified three simple questions, which were reliable at identifying leg and back dominant pain. These questions were independently administered to a consecutive cohort of fifty-two lumbar patients prior to consultation with one of four spinal surgeons at a tertiary academic centre. Phase II involved an acute spinal pain centre, staffed by pain specialists, who have been orientated on appropriate indications for referral. The mandate of this clinic was to assess patients with acute or subacute back pain within two weeks of referral. A similar questionnaire as the one used in Phase I was independently administered to the first ninety lumbar patients attending the clinic in Phase II. All patients were followed independently to determine if surgery was recommended or performed and compared against the baseline questionnaires, findings on CT/MRI scan or pain specialist’s referrals.

The questionnaire identified twenty (38.5%) patients with clearly back dominant pain in Phase I and 56 (62.2%) patients in Phase II. Of the eighteen patients that had surgery or were recommended to have surgery, none had clearly back dominant pain as identified by the questionnaire for a combined sensitivity of 100%. When compared against the patient’s CT/MRI scans in phase I and the pain specialists referrals in Phase II, the questionnaire was more accurate at identifying surgical candidates.

This study has demonstrated in multiple settings that a simple questionnaire of three questions can identify patients requiring surgery and may be more specific than standard referrals, CT/MRI scans, or pain specialist’s assessments. Further work is required to refine this screening process and evaluate it prospectively.

D. Costain D. Alexander M. Gross W. Oxner

The referral time for spine surgery consultation in Halifax is approximately one year. We currently do not understand the significance of delay in surgical consultation, nor do we have documentation of patient-perceived effects of this delay. Identifying patient characteristics associated with spine pathology mandating earlier surgical intervention would have obvious benefit in streamlining this population in our referral pattern. Furthermore, outlining patient characteristics who are unlikely to benefit from orthopaedic surgical assessment for spine surgery may facilitate community management of spinal pathology and accordingly improve wait times for surgical consultation.

The aim of this study was to Identify patient variables that are predictive of need for early surgical evaluation. Also, to assess patient and surgeon satisfaction with wait times for consultation.

Demographic data and questionnaires were prospectively collected on all consenting patients seen by two orthopaedic spine surgeons over a two week period. Patient and surgeon impression of wait was documented, in addition to Oswestry Disability Index (ODI) scores, and the Visual Analogue Scale (VAS) to document pain. Surgeon reasons for scheduling or delaying surgical planning were also documented and correlated to patient scores.

The average wait time for surgical consultation was 9.7 months, with a mode of sixteen months. 62.8% of patients felt that earlier consultation would be more appropriate, while 31.1% felt that they had deteriorated due to the delay. In addition, 26% felt that the delay negatively influenced their prognosis. Treating surgeons felt that the patient should have been seen sooner in 39% of cases, and that delay in consultation negatively affected prognosis in 6.2% of cases. Of two hundred and forty-two patients completing the survey over the two week period, only ten (4.1%) were scheduled for surgery.

Both patients and physicians felt that prolonged referral-consultation wait times were unacceptable, and deleteriously affected prognosis in a significant proportion of cases. The majority of patients seen were not deemed surgical candidates, indicating room for improvement in referral patterns.

P. Perkins T. Burd P. Huddleston K. Knapp D. Kovalsky S. Robbins K. Wood

We present our experience with the use of the Anterior Tension Band plate (ATB) following ALIF, which utilises the existing surgical approach obviating the need for posterior fixation. The ATB is a small, smooth, low profile plate. It can be placed through the existing approach (anterolateral retroperitoneal or anterior transperitoneal) across the reconstructed level to prevent extension of the graft space and anterior migration of the spacer. The primary objective of this study is to measure radiographic fusion success in patients with lumbar degenerative disc disease using the ATB system. The secondary objective is to accurately define the clinical benefits to the patient.

This is a prospective multi-center outcome study. Each patient was treated with an ATB plate at one or two levels between L2 & S1 and 1 ALIF or FRA allograft spacer per level. Patient data (VAS Pain, SF-12 and Oswestry) was collected preoperatively, and at six, twelve and twenty-four month post-operative intervals. Fusion was evaluated upon demonstration of bridging trabecular bone through or external to the femoral ring. Secondary endpoint success includes demonstration of 15% improvement over baseline on the VAS, Oswestry and SF-12 patient questionnaires.

To date one hundred and thirty-one patients have undergone surgery. There were ninety-two (70%) single-level ALIF procedures and thirty-nine (30%) two-level ALIF procedures. Patients that have returned for twelve month follow-up (n=41) have had a fusion success rate of 81%. The fusion rate among one-level patients is 89% (n=25) and 67% (n=15) among two-level patients. Four of five of the un-fused two-level patients had one level fused but not the other. At twelve months, Oswestry scores improved by an average of 40% with thirty-one of forty-seven (66%) patients achieving success and VAS scores improved by 42% with thirty-five of forty-seven (75%) being successful.

Preliminary analysis of current data shows positive outcomes using the ATB plating system in ALIF procedures. Primary and secondary outcomes are compatible with current standards of care, and device related complications are minimal. Further analysis of outcome data including will be reported upon the completion of the study.

A. Sethi S. Bartol J. Carp J. Craig R. Vaidya

This study was performed to evaluate the clinical and radiographic outcomes in patients undergoing anterior cervical discectomy and fusion (ACDF) with rhBMP-2 and polyetheretherketone (PEEK) cages with our standard treatment of allograft spacers and demineralised bone matrix.

Forty-six patients who underwent primary ACDF were included in the study. Twenty two patients with PEEK spacers and rhBMP-2 were compared to twenty four patients with allograft spacers and demineralised bone matrix all supplemented with an anterior locking plate. All patients were examined preoperatively and at two, six, twelve and twenty-four weeks and one and two years following surgery. Their cervical Oswestry scores,VAS for neck and arm pain and a pain diagram were recorded at every visit. A radiographic examination was also performed and patients were questioned for dysphagia, hoarseness of voice and any other difficulties. Radiographs were evaluated for prevertebral swelling, bone formation, subsidence and likelihood of fusion. CT scans were performed in any individual at twelve months if there was a concern of non union.

There was no significant difference in pain scores between rhBMP-2 and allograft spacer patients. There was improvement in both groups from their preoperative scores. Incidence of hoarseness of voice was also similar in both groups. There were statistically significant more patients with dysphagia in the rhBMP-2 group at two and six weeks following surgery. All patients in the rhBMP-2 group achieved a radiological diagnosis of probable fusion at their latest follow up (thirty-eight levels). In the allograft group 23/24 patients achieved a diagnosis of probable fusion (39/40 levels). End plate resorption was observed radiologically in 100% of the levels where rhBMP-2 was used. Prevertebral swelling on lateral radiographs was significantly greater in patients with rhBMP-2 causing dysphagia. The cost of implants was three times higher in patients with PEEK cage and rhBMP-2.

The use of rhBMP-2 leads to consistent fusion in the cervical spine. Significantly higher rates of prevertebral swelling, dysphagia and s higher cost are major drawbacks. End plate resorption was an unusual radiographic finding with the use of rhBMP-2.

R. Rampersaud R. Barron J.R. Davey S.J. Lewis N. Mahomed B. Ravi R. Rampersaud

The primary objective of this study was to determine if surgical treatment for spinal stenosis is comparable to total hip and knee arthroplasty in improving patients’ self-reported quality of life. An age, sex and time of surgery matched cohort of patients who had undergone elective primary one-two level spinal decompression (n=90) with (n=26 /90) or without fusion for spinal stenosis (n=40 with degenerative spondylolisthesis) and elective primary total hip (n=90) and knee (n = 90) arthroplasty for osteoarthritis were compared. The primary outcome measure was the preoperative and two year postoperative Medical Outcomes Study Short Form-36 (SF-36) questionnaire.

There was no significant difference in the mean pre-operative Physical Component Summary (PCS) / Mental Component Summary between groups [Spine −32/43; Hip − 30/45; Knee 31/46 (p > 0.5)]. With the exception of the knee MCS (p=0.2), postoperative scores were significantly improved for all groups [Spine −40/53; Hip − 43/51; Knee 39/48 (p < 0.001)]. Overall the hip surgery had the great impact on PCS and the spine surgery on MCS.

Studies have shown the significant impact on overall patient quality of life and cost-effectiveness of primary total joint arthroplasty. The results of this unique study show that surgical intervention for spinal stenosis has a similar positive effect at two year follow up. This study provides data that supports the need advocacy regarding waiting time initiatives and surgical resources for the treatment of patients with symptomatic spinal stenosis with a similar demographic to those with primary OA of the hip or knee.

C. Hui N. Cooper S. Goldstein J. Howard E. Joughin

The purpose of this study was to determine the prevalence of non-accidental injury in toddlers (birth to two years old) presenting with a femur fracture to a single institution within a Western Canadian population. There are currently no Canadian studies that investigate this association in the medical literature.

A retrospective case-control study was performed for children less than or equal to two years of age with a diagnosis of femur fracture who presented to a single institution from 1994 to 2005. Patients with associated pathological or metabolic bone disorders were excluded. The primary outcome measure was the prevalence of non-accidental injury associated with femur fracture. Secondary outcome measures included: patient demographics, injury characteristics, radiologic and other work-up, and suspicion of abuse. Statistical analysis was performed using tests of analysis of variance and multivariate analysis to identify independent and significant risk factors associated with non-accidental injury.

One hundred twenty-seven children that met the inclusion criteria were identified. The overall prevalence of non-accidental injury was 11% (14/127 patients) and 17% (10/60 patients) in children under twelve months. Mean age was twelve months in the abused group and sixteen months in the accidental group. Forty-three percent of the abused group had delayed presentation compared to 8% of the accidental group. In the abused group, 43% had unknown, unwitnessed, inconsistent histories versus 4% in the accidental group. No specific fracture pattern or location suggestive for non-accidental injury was identified. Forty-three percent (6/14 patients) of the abused group and 12% (13/113 patients) of the accidental group had other injuries. Multivariate analysis determined that delayed presentation (p=0.001), mechanism of injury (p=0.02) and other associated injuries (p=0.003) were the only independently significant risk factors for abuse.

Toddlers who present with femoral fracture are at risk for associated non-accidental injury though perhaps this risk is not as high as previously thought. Regardless, a high index of suspicion is mandatory when these children are encountered and careful screening with a thorough history, physical examination, and other investigations where indicated, are warranted to rule out associated child abuse.

P. J. Moroz S. Al-Amir R. Baxter Willis

To compare the clinical and radiographic outcomes of Type III supracondylar fractures of the humerus in children managed either by open reduction and internal fixation versus those treated by closed reduction and percutaneous pinning. The indications for open reduction included an inability to obtain a satisfactory reduction by closed means; open fractures and fractures with vascular compromise after closed reduction.

Retrospective chart and radiograph review over a ten year period (1995–2005), with two hundred and thirty-six children with Type III fractures treated at a Level One pediatric hospital within a universal health-care system.

One hundred and seventy by closed reduction and percutaneous pinning and sixty-six by open reduction. The left arm was involved in one hundred and forty-eight cases and twenty-five patients had vascular compromise at presentation but no cases required vascular repair. There were ten open fractures in the open reduction group. The anterior approach was employed in twenty-nine patients, anteromedial in twenty-two and anterolateral, medial and lateral in equal preference. Entrapped structures included brachialis muscle in thirty-four patients, periosteum in eighteen, radial nerve in two, medial nerve in two, and the brachial artery in one. According to Flynn’s criteria, the open reduction group had an excellent or good outcome in 90% of cases while the closed reduction group had an 80% excellent or good outcome.

In this study of displaced Type III supracondylar fractures, there was a higher rate of open reduction than was initially anticipated. There was a higher rate of excellent and good outcomes in the ORIF group but this may be due to a relatively short follow-up in the closed reduction group. Post reduction stiffness would likely dissipate and allow a higher rate of excellent and good outcomes in the closed reduction group. An anterior approach or variation of an anterior approach is best suited to visualise the anatomy and structures hindering the reduction. Despite this, there was no clinical or radiographic difference between the approaches employed. In conclusion, open reduction and internal fixation if displaced Type III supracondylar fractures is a safe and effective procedure. An anterior approach is recommended to identify and relieve the soft tissue obstacles to a suitable reduction. Significance: This study furthers the literature that proposes to lower the threshold for open versus closed reduction of displaced supercondylar fractures in children.

M. Sabo T. Carey K. Leitch

Chronic spastic hip dislocation in patients with spastic quadriplegia can lead to restricted range of movement and severe pain, inability to sit, respiratory and urinary infections, perineal hygiene problems and decubitus ulceration. The Castle procedure is designed to relieve pain and prevent these complications. This investigation evaluates whether the Castle procedure succeeds as a salvage procedure in a pediatric population.

Patients with cerebral palsy who had undergone a proximal femoral resection according to Castle’s description were identified. Exclusion criteria included age over nineteen years at time of surgery, acute hip dislocation, and diagnoses other than cerebral palsy. Eight children completed a chart and radiographic review, and a clinical review. A staff physician evaluated range of motion, apparent discomfort of the child, and the state of the perineal skin. A questionnaire was given the primary caregiver assessing post-operative improvement in pain, sitting duration, infections, ulcers, ease of postoperative care, and overall satisfaction.

Five males and three females with mean age at surgery of 13 ± 1 years, and an average follow-up of 42 ± 13 months were enrolled. All had proximal migration of the residual femur to at least the midpoint of the acetabulum. The average heterotopic ossification score post-op was Brooker one with no symptoms. Five of eight had mild discomfort, with two having moderate to severe discomfort. Five had reduced pain post-op such that they didn’t require analgesics, and were able to sit the entire day. One had a urinary infection post-op, and two had recurrent pneumonias and decubitus ulcerations postop. One child underwent a revision resection for pain and proximal migration, and one was rehospitalised for failure to thrive and pain control. Seven of eight caregivers were somewhat or very satisfied with the procedure, but only five of eight would recommend it to others. Problems identified by the caregivers included treatment failure, difficulty with post-operative care, and significant leg length discrepancy.

The Castle procedure is a successful salvage in severe spastic hip disease, but not universally so. Education concerning potential outcomes and rehabilitation period is also essential in achieving satisfaction.

R. B. Willis

The purpose of this paper was to evaluate the early results of a new technique for correction of angular deformity in adolescents.

A retrospective review of all patients and radiographs undergoing an open wedge technique of corrective osteotomy employing a special plate designed to keep the osteotomy open at a precise amount was carried out.

From 2000–2005, eleven patients have been treated by the author using this technique. Indications for surgery included adolescent Blount’s disease or Tibia Vara in eight cases, growth arrest after fracture of the proximal tibia in one case, distal tibia in one case and developmental genu valgum in one case. The mechanical axis was restored to normal in ten of the eleven cases. One patient with adolescent Blount’s disease remained in slight varus despite the maximum available correction of 22.5 degrees. All patients healed radiographically in eight to ten weeks. Two patients have had their plates and screws removed after union of the osteotomy because of the high profile construct.

Excellent results can be achieved for correction of angular deformity in adolescents with use of a special plate designed for an open wedge technique. Attention to preserving the opposite cortex at the time of the osteotomy is critical to the success of the procedure. A maximum of approximately 20 degrees of correction is possible with this technique. Early union of the osteotomy and restoration of function give this technique specific advantages over other methods.

L. Murnaghan B. B. Forster R. Hawkins B. J. Sawatzky C. H. Thurgur S. J. Tredwell

To provide a comprehensive radiographic, clinical, and functional description of the shoulder in Apert Syndrome.

A cohort of nine Apert Syndrome patients (ages nine to twenty-seven) followed at a tertiary care facility was included in this prospective study. Patients were clinically assessed with physical examination and completion of two validated functional assessment tools, the Shoulder Pain and Disability Index (SPADI) and AAOS Paediatrics Questionnaire (PODCI). Radiographs were obtained of both shoulders and a standardised protocol MRI was performed on the dominant shoulder of all participants.

All patients had some degree of functional impairment attributable to their shoulder pathology. Physical examination consistently revealed reduced forward flex-ion and abduction. Radiographic findings were similar to previous reports, with pervasive osseous dysplasia of the shoulder joint. Medial humeral head hypoplasia was seen in eight out of nine patients and greater tuberosity overgrowth in seven out of nine patients. MR imaging of the shoulder, not previously performed in a cohort of Apert patients, allowed better delineation of abnormalities seen radiographically such as a central glenoid cleft, seen in eight out of nine patients. It also revealed a new finding of inferior glenoid inclination (seven out of nine patients), which has not been described in the literature. Very few soft tissue or degenerative abnormalities were demonstrated.

The findings of this study confirm that patients with Apert Syndrome are functionally impaired by their shoulder pathology, which may have a similar clinical impact as the more well-described hand and foot anomalies. The global functioning of patients with Apert syndrome is equivalent to patients with juvenile rheumatoid arthritis. The shoulder range of motion in Apert patients is decreased, most significantly in flexion and abduction. Radiographs confirmed previous imaging findings of glenohumeral dysplasia. The novel MRI component demonstrated consistent inferior glenoid inclination, which may be a significant factor in their shoulder impairment. MR imaging revealed no significant soft tissue or degenerative abnormalities to account for their clinical disability. These findings have potential relevance in the surgical and clinical management of these patients.

T. Carey K. Leitch C. Scholtes F. Stephenson

Serial casting (SC) and Botulinum toxin-A (Btx-A) have been used to treat ankle equinus contractures in cerebral palsy. Previous studies that examined the effects of combining Btx-A injections with SC and either one of the treatments alone in terms of passive ankle range of motion (PROM) have shown mixed results [two-four]. Therefore, the goal of this study is to examine PROM and gait characteristics in children with CP who have undergone SC, either with or without Btx-A injections to the plantarflexors.

Patients who underwent SC +/− Btx-A injections were evaluated for improvement in PROM at the end of treatment. The participants’ age at beginning of SC treatment, Gross Motor Function Classification System (GMFCS) level, treatment duration, PROM, and gait characteristics observed by the treating physiotherapist were obtained from the charts. Only one side per treatment is included in this study (treated side for unilateral treatments, randomly chosen side for bilateral treatments). Table One shows the characteristics of the two groups.

Independent samples t-tests showed that the two groups are similar in terms of age, treatment duration and pre PROM. A repeated measures ANCOVA, using the pre- and post- treatment range of motion as the within subject variables, treatment type as the between subject variable, and GMFCS and age as the covariates showed that the PROM changed significantly regardless of treatment type (p< 0.001). However, the treatment type does not influence the outcome (p=0.411). The changes in range of motion obtained from the two types of treatments were not significantly different using the independent t-test (p=0.957).

Based on these results, it appears that both types of interventions resulted in significant changes in ankle passive range of motion, which is in agreement with Kay et al [4]. Similar ranges of motion at the end of the treatment were obtained from both treatments, and the treatments have similar success rates. Future work is needed to further explore the outcomes associated with serial casting only and Btx-A and serial casting treatments

D. Jacks C. Alvarez A. Black M. DeVera

Clubfoot is a complex three-dimensional deformity that is difficult to assess by clinical examination and conventional radiography. Pedobarography has been established as a useful technique for measuring pressure profiles of the foot, however its utility in the clubfoot population has not been established. The purpose of the present study is to describe the pedobarographic profiles of children with clubfeet and to establish the significant variables when compared with aged-matched controls.

Pedobarographic profiles were obtained using the Tekscan HR Mat Pressure Measurement System and data was analyzed using a custom built LabView program. Clubfoot patients aged 18 months to four years (n = 190) were tested and compared to aged matched controls (n = 82). Each foot was divided into five segments (heel, medial and lateral midfoot, medial and lateral forefoot) and each segment was analyzed for timing of initiation of force, timing of termination of force, force distribution, and impulse. The mean and standard deviation were calculated for each variable. Clubfoot pedobarographic means were compared to the aged matched controls and significant variables were identified using Student’s paired t-test (p < .05).

Nine of twenty-five variables were found to be significantly different in the clubfoot population. The heel showed a reduced force and impulse. The lateral mid-foot showed an increased force and impulse with an earlier initiation and later termination of forces. The medial forefoot showed a decrease force and impulse with a later initiation of force.

Pedobarography has been found to be a useful tool in the evaluation of foot pathology, but its utility in the clubfoot population has yet to be established. In this study, we describe the pedobarographic profiles of children with clubfeet and have noted significant differences when compared to age-matched controls.

M. Glazebrook J. Amirault K. Arsenault A. Hennigar A. Raizah K. Trask

The purpose of this study is to assess the clinical outcome and gait analysis of a new technique for ankle arthrodesis using a Fibular Sparing Z Osteotomy (FSZO).

The FSZO technique for ankle arthrodesis utilises a lateral approach where the fibula is osteotomised and reflected posteriorly on a soft tissue hinge to allow easy access to the ankle joint for an anatomic arthrodesis. Outcome assessment at six months follow up included health related quality of life (SF36) and joint specific (American Orthopedic Foot and Ankle Society Ankle-Hindfoot, Ankle Osteoarthritis Scale, Foot Function Index) clinical outcome scores. Gait Analysis was completed using the Walkabout Portable Gait Monitor® which includes a wireless gait belt housing a triaxial arrangement of accelerometers, resting behind the lumbar vertebrae, approximately at position of centre of mass to quatintfy surgery, lurch and functional limb length difference (LLD).

There was a significant improvement in the health related quality of life and the joint specific clinical outcome scores at six months follow up. The six month gait study preliminary analysis showed improvement in some parameters of gait but worsening in others.

The FSZO ankle arthrodesis technique provides improvement in clinical outcome scores and certain gait parameters at early follow up.

R. El-Hawary K. Jeans L. A. Karol B. Stephens Richards

To evaluate the gait of five-year old children with club-feet initially treated non-operatively with the French functional technique and to compare these results to the data from this same cohort at the age of two years. Thirty-three patients (fifty-two idiopathic clubfeet) were initially treated with the French functional (physiotherapy) program. At the age of two years, no child underwent surgery for its clubfoot. Gait Analysis was performed with the VICON system (kinematics). At the age of five years, these patients were all re-evaluated in the gait laboratory.

Of the thirty-three patients (fifty-two clubfeet) initially treated non-operatively and tested in the gait lab at two years of age, thirty-seven feet required subsequent surgery by the age of five years. This included posterior release (41%), posteromedial release (35%), tibial osteotomy (19%), and tendo Achilles lengthening (5%). The proportion of feet with the following gait parameters changed significantly (p< 0.05) between the ages of two and five years: Equinus (15% at 2 yrs vs. 2% at 5 yrs), Calcaneus (7% vs. 23%), Foot Drop (18% vs. 4%). The proportion of patients with internal foot progression angle did not change over this time (46% vs. 50%), nor did the proportion with normal sagittal plane ankle motion (61% vs. 54%). At age two years, the majority of patients treated with the French Functional non-operative treatment had normal sagittal plane ankle motion. Gait disturbances, when present at this age, were generally ankle equinus, foot drop and in-toeing. By the age of five years, 71% of these patients underwent surgery for their clubfeet. When re-tested in the gait laboratory at age five years, the proportion of feet with normal sagittal plane ankle motion did not change significantly, however, their resultant gait disturbances, when present, were predominantly calcaneus rather than equinus and foot drop. By treating patients with clubfeet with the French Functional technique exclusively, equinus gait may result in a small proportion.

By subsequently treating these patients surgically after the age of two years, over-lengthening or over-release may occur and result in calcaneus gait. The French originators of this technique now incorporate an early gastrocsnemius fascial lengthening as part of their technique. This modification of their technique should improve the gait characteristics observed at two years of age and should decrease the necessity for late surgery that may have contributed to the gait characteristics observed at five years of age.

K. Pruthi

Delayed presentation of displaced supracondylar elbow fractures in children is a unique problem, but not uncommon in our hospital settings. The purpose of this study was to evaluate the results of our novel technique of closed manipulation and percutaneous pinning of these late presenting fractures.

We used this technique in fourteen children, with an average age of seven years five months, who presented after an average delay of sixteen days. Through a limited incision technique, manipulation was done using a long curved artery forceps (under image intensifier). Final realignment was obtained and cross k wire fixation done.

At follow-up (average twenty-two months) there were only four children who had cubitus varus greater than one hundred and needed corrective osteotomy. There were no neurovascular injuries. The other two patients with cubitus varus of sixty were satisfied with the appearance of their elbow. Final evaluation was done using Flynn criterion.

The procedure however is quite demanding and needs expertise in closed pinning techniques. Though this technique holds promise in managing the difficult “SUPRACONDYLAR DILEMA”, yet larger series and multicentric trials are needed to establish the efficacy.

J.G. Jarvis S. Sathiaseelan

Superior mesenteric artery (SMA) syndrome is a rare medical complication of scoliosis surgery. In order to delineate the clinical features, progression and treatment of duodenal obstruction due to SMA syndrome after spinal fusions and to determine the relationship between spinal deformity correction and SMA syndrome, a retrospective study of all patients developing SMA syndrome following spinal fusion was conducted at a tertiary care center.

Charts were reviewed for symptoms of SMA syndrome, type and magnitude of spinal deformity, age at surgery, radiographic correction, complications, and other medical problems. The information gathered was divided according to non-orthopaedic and orthopaedic parameters.

All patients (five female and three male) in this study had spinal fusions performed. Overall, the patients were skeletally mature with a Risser stage average of 3.6. The average correction in the coronal plane was 28.4% in the thoracic spine and 44.6% in the lumbar spine. Sagittal correction averaged 25.9 % and 27% in the thoracic and lumbar spines respectively.. BMI index average was 17.6 (i.e. under-weight individuals). Signs and symptoms of SMA syndrome such as nausea, vomiting, epigastric pain, bloating, and weight loss developed at an average of 11.6 days. Seven patients were managed conservatively, and only one patient required surgery. All patients recovered fully.

This study identified purely asthenic body habitus (low BMI) and significant coronal correction in the lumbar region as risk factors for the development of SMA syndrome after spinal fusion Prolonged nausea and vomiting after spinal fusion requires GI imaging to rule out SMA syndrome, particularly within the first seven-ten days of surgery. Clinicians should also be aware of the possible delayed onset of symptoms in some patients. Nutritional support should be started immediately to prevent further adverse outcomes.

L. Yi-Jia T. L.. Chuan L. E. Hin

Syndactyly and polysyndactyly of the feet are common congenital conditions of the foot, and surgery to reconstruct the toes may be indicated for cosmetic, psychological, and practical reasons. A dorsal flap is traditionally used for the web space reconstruction, with skin grafts for the bases of the toes. Skin grafting has associated morbidity, and can result in pigmentation mis-match. Single-stage direct closure using a specially designed dorsal pentagonal island flap has advantages including a reduction of morbidity from avoidance of skin grafting, and shorter surgery.

Four patients with six feet were included in the study. There were two cases of syndactyly, and two cases of polysyndactyly. Bilateral involvement occurred in two patients. The average age was eighteen months at time of first surgery. Direct closure was achieved with a dorsal pentagonal island flap with dorsal and plantar triangular flaps. The average duration of follow-up was 19.8 months.

At final follow-up, all patients had acceptable web depth and pulp contour. The distance between bilateral proximal interphalangeal joints of adjacent toes, and the web slope of the reconstructed web space were compared. Complications included partial synechiae, cellulitis and keloid formation.

The dorsal pentagonal island flap is an acceptable technique in providing another means for single-stage reconstruction of the web space in syndactyly and polysyndactyly. Good functional and cosmetic outcomes can be expected. However, the potential complication of keloid formation can affect cosmesis and overall outcome, and must be understood by patients and parents.

E. H. Schemitsch P. A. Cole MN St. Paul R. Zdero M. Talbot D. Garneau

Gaining stable fixation in cases of recalcitrant non-unions can be challenging. These cases can be accompanied by a segmental bone defect and disuse osteopenia. One strategy to gain stable fixation is the use of allografts. Both cortical struts and intramedullary fibular allografts have been used for this purpose in the femur, tibia and humerus. The present study aims to compare the mechanical properties a locking plate, an intramedullary fibular strut allograft and a cortical strut allograft in a femur model of segmental bone defect.

A transverse mid-shaft osteotomy was performed in fifteen third generation large composite femurs. Twelve millimeters of bone was resected to create a segmental bone defect. Fixation was undertaken as follows: Construct F (Fibula): Lateral Non Locking plate and Intramedullary Fibula Allograft Construct LP (Locking Plate): Lateral Locking Plate Constrcut S (Strut): Lateral Non-Locking Plate and Medial Cortical Strut Allograft Axial, Torsional and Bending Stiffness as well as Load-to-Failure were determined using an Instron 8874 materials testing machine.

Overall, construct S was the stiffest, construct F intermediate and construct LP the least stiff. Specifically, the S construct was significantly (p< 0.05) stiffer than the two other constructs in the axial, coronal plane bending, sagital plane bending and torsional modes. Construct F was significantly stiffer than construct LP in the axial and coronal plane bending modes only. Both the S construct (6108 N) and the F construct (5344 N) had a greater Load-to-Failure than the LP construct (2855 N) (p=0.005 and 0.001 respectively).

The construct with a lateral non-locking plate and a medial allograft strut was stiffer and had a higher load-to-failure than the construct consisting of a stand-alone locking plate. An intramedullary fibular allograft with a lateral non-locking plate had intermediate characteristics. Other factors, such as anatomic and biologic considerations need to be considered before choosing one of the above constructs. The allograft procedures should only be used once soft tissue coverage has been obtained and any infection eradicated.

M. Prud’homme Foster S. Papp P. Poitras

Biomechanical stability is important for fracture healing. With standard plate and screw constructs, longer plates with screws well spaced, near and far from the fracture site, are biomechanically superior. Newer locked plates have been shown to be superior to conventional plating for difficult fractures. The ideal screw configuration for fixation with locked plates has yet to be addressed. This study investigates the effects of screw position on construct stiffness as well as strain in both the plate and bone during fixation of a diaphyseal comminuted fracture using a locking plate with bicortical fixation.

A composite cylinder (Sawbones) was machined to produce two models:

(a) comminuted model (4mm gap) and

(b) whole model (no gap) to simulate the remodelling phase.

Five strain gauges were mounted to the bone models and one between the center holes of the locking plate. Four different configurations of screw number and position were evaluated using a twelve-hole locking plate (Smith & Nephew Perilock). Plate holes were numbered on each side of the gap from one to six. Screw configuration 654321, 621, 654 and 321 were tested in four-point bending on an MTS 858 Mini-Bionix. Force (N) and displacement (mm) as well as strain readings were recorded at 10 Hz.

Plate strain in the gap model did not vary significantly for the different configurations. Construct stiffness of the 654 model (all screws far from gap) showed a 30% decrease in stiffness as compared to other screw configurations (p< 0.001). In the whole bone model, the maximal bone strain was outside the farthest screw from the center of the plate (stress shielding) and bone strain at the fracture site in 654 was significantly higher than in 621 (p< 0.001).

Results showed that three screw fixation produced similar construct stiffness to a six screw construct when well spaced. Three screws placed far from the fracture gap (654) as compared to three screws evenly spaced (621) showed decreased stability in the comminuted model but resulted in increased bone strain at the fracture site in the whole bone model. All configurations produced similar plate strain.

J. L. Howard J. Agel D. P. Barei C. Coles

This study was designed to answer the question “Is there a difference in outcome following operative management of AO type C distal humerus fractures for patients with associated injuries compared to those with isolated injuries?” Our hypothesis was that patients with associated injuries would have worse outcomes compared to those with isolated injuries.

Fifty-eight patients with fifty-eight fractures managed with ORIF were included. Hospital records, clinic notes and radiographs of these patients were retrospectively reviewed. MFA and DASH scores were prospectively obtained after patients were identified (mean 37.4 months post injury, range 6–74 months).

Thirty-two patients had isolated distal humeral fractures while twenty-six patients had distal humeral fractures with associated injuries. The mean MFA of patients with isolated injuries was significantly lower than for patients with associated injuries (27.2 vs 41.7, p = 0.01). There was no difference in DASH scores between the two groups (23.7 vs 29.1, p = 0.34). The mean postoperative arc of motion was one hundred and seven degrees for isolated injuries and seventy-five degrees for patients with associated injuries (p=0.006). Surgical release for stiffness was required for two patients (6%) in the isolated group and ten patients (38%) in the associated injuries group (p=0.003).

Outcomes for isolated distal humeral fractures in this study were comparable to previously published literature. Patients who sustain associated injuries at the time of distal humeral fracture have more stiffness and a worse outcome on a global outcome score, but a similar outcome on a limb specific outcome score.

D. Young R. Feibel S. Papp P. Poitras N. Ramachandran

There is theoretical concern that volar plating has a disadvantage in cantilever bending when axially loaded dorsal to the neutral axis. This has implications for postoperative rehabilitation protocols and overall outcomes related to maintenance of reduction. Most recent biomechanical studies have compared volar locking plates to traditional dorsal non-locked plates. The purpose of this study was to compare the biomechanical stability of volar and dorsal locking plate fixation in a model of dorsally unstable distal radius fractures.

Fourteen synthetic composite radii (Pacific Research Laboratories, Vashon, WA) were used for this study. A dorsally unstable, extra-articular distal radius fracture was simulated by creating a dorsal wedge-shaped defect in the distal metaphysis. Half of the specimens were plated dorsally (n=7) while the other half were plated volarly (n=7) with 2.4mm distal radius locking T-plates (Synthes, Canada). Each specimen was loaded axially in five different positions: central (along the neutral axis of the radius) as well as dorsal, volar, radial and ulnar to the neutral axis using a MTS Sintech 1/G materials testing machine (MTS Systems, Eden Prairie, MN). The plated radii were loaded to 100 N in each position simulating physiological loading during normal range of motion. The main outcome measure was construct stiffness of the plate-bone system (slope of load-displacement curve) for all five loading positions.

Construct stiffness with dorsal locking plates was seven times greater than volar locking plates when dorsally loaded (p < 0.001), 60% greater when centrally loaded (p = 0.055) and 35% greater when volarly loaded (p = 0.029). There was no significant difference in stiffness with any other loading configurations.

The stability of dorsal locking plate fixation is superior to volar locking plate fixation in the setting of large dorsal defects in the distal radius. This is applicable to both fractures with dorsal comminution and dorsal opening-wedge distal radial osteotomies. Further clinical investigation is needed to compare functional outcomes and complication rates between modern dorsal and volar locking plate techniques.

E. Pally G. Johnston

The purpose for this study was to investigate the site marking practice for emergent and non-emergent orthopedic surgery at the authors’ orthopedic teaching program. One author attended surgeries at two hospitals in 2006, documenting the presence or absence of an unambiguous mark in the prepped and draped surgical field. Although emergent and elective cases were “chosen”, there was no intentional selection bias.

Forty-eight surgeries by eleven surgeons were evaluated. After draping a mark was visible in twelve of eighteen (67%) emergent cases, and twenty-seven of thirty (90%) non-emergent cases. In the nine cases in which no mark was visible, two had been draped out, one had been washed off, two had never been marked, and in four cases the cause was uncertain.

The authors would suggest that surgeons were near fully “compliant” with the COA protocol in non-emergent cases, but “complacent” in emergent ones. Wrong site surgery is an event that results in irrevocable harm to the patient - orthopaedic surgeons should recognise the value of pre-operative skin marking for all procedures, and re-evaluate their own personal practices in light of our results.

W. Gofton D. Backstein A. Dubrowski F. Tabloie

Rapid advances in computer-assisted surgery (CAS) have lead to increasing integration of this technology into the orthopaedic training environment. The real-time feedback provided by CAS improves performance; however, it may be detrimental to learning. The primary purpose of this study is to determine if the form of feedback provided by computer-assisted technology (concurrent visual feedback) compromises the learning of surgical skills in the trainee.

Forty-five residents and senior medical students were randomised to one of three training groups and learned technical skills related to total hip replacement. The “Conventional Training” (CT) group self-determined acetabular cup position and were then corrected with traditional hand-over-hand repositioning. The “Computer Navigation” (CN) group used CAS to self-determine cup position. The “Knowledge of Results” (KR) group self-determined cup position and when satisfied used CAS for optimal repositioning. Outcomes (accuracy and precision of cup placement in abduction and anteversion, and time to position) were assessed in a pre-test, ten minute and six week retention and transfer tests. All retention and transfer tests were performed without CAS.

There were no differences between the groups at pre-test. All groups demonstrated an improvement in accuracy and precision of abduction angle and version angle determination during training (p < 0.001). The CN group demonstrated significantly better accuracy and precision in early training (p < 0.05), and better precision throughout training (p < 0.05). While the CN group demonstrated a decrease in precision during transfer testing it was not found to differ significantly from the other groups. No significant degradation in performance was observed between immediate and delayed testing for any group suggesting no negative effects of the tested training modalities on learning.

In this study the concurrent augmented feedback provided by CAS resulted in improved early performance without a compromise in learning, however, further investigation is required to ensure CAS does not compromise trainee learning. Until this issue is clarified, educators need to be aware of this potential effect.

D. Pulisetty J. G. Ramon

A prospective study to examine the outcome of closed fixation technique in managing the unstable, intra-articular fractures of the distal radius by using k-wires only is undertaken.

Sixty-two wrists with unstable distal radius fractures were treated with closed manipulation and closed pinning of the fracture. Ten are between fifty-one and eighty-one years old and fifty-two are below fifty years of age. Both readial styloid and the dorsal cortex of the distal fragment provided the entry points. All fractures were reduced with fingfer trap traction. Tran osseous and intra-medulaary pinning was carried out in all the fractures. In this two step technique, first the radial articular surface is stabilised. Then, axial stability is provided by trans-epiphyseal intramedullary nails. Emphasis was laid on the reduction, complications and fracture healing.

All fractures healed. A ‘concentric’ collapse varying from 1 to 3 mm was seen in twenty-six cases. No loss of reduction was seen. Surprisingly, no cutaneous radial nerve injuries, no tendon related complications were seen. Five pins in three patients were loose and were removed betweeen seven to thirty days. None had repeat surgeries.

Sound technique is key to success. The longer the collective length of the intra- medullary pins the greater remained the stability of the fracture construct. Ulnar bone provides as a pillar to assemble the distal radius. Fracture of the distal ulna (not merely a fracure of the ulnar styloid) required an additional support in the form of an external fixator in only two patients. Since the follow-up is not very long (mean six months), the author contends to say that the short term results are rewarding with this technique. The unsatisfactory results reported in literature from the closed pinning is largely from inadequate fixations used. When proper technique is applied the radial articular surface is held on the distal shaft to permit only a minimal collapse that is concentric; and compression at the fracture site promoting excellent healing is the rewarding result.

M. Bhandari J. Siegel J. Sung P. Tornetta

We aimed to quantify the sample sizes and magnitude of treatment effects in a review of orthopaedic randomised trials with statistically significant findings.

We conducted a comprehensive search (PubMed, Cochrane) for all randomised controlled trials between 1/1/95 to 12/31/04. For continuous outcome measures (ie functional scores), we calculated effect sizes (mean difference/standard deviation). Dichotomous variables (ie infection, nonunion) were summarised as absolute risk differences and relative risk reductions (RRR). Effect sizes > 0.80 and RRRs> 50% were defined as large effects.

Our search yielded 433 RCTs, of which 76 RCTs with statistically significant findings on 184 outcomes (122 continuous/62 dichotomous outcomes) met study eligibility criteria. The mean effect size across studies with continuous outcome variables was 1.7 (95% confidence interval: 1.43–1.97). Almost one in three results, despite being reported as statistically significant did meet the definition of a large effect size (ES< 0.80). For dichotomous outcomes, the mean risk difference was 30% (95%confidence interval:24%–36%) and the mean relative risk reduction was 61%.

J. A. Hall M. Faruggia M. D. McKee D. Pearce J. Potter

Malunion following displaced fractures of clavicle most commonly occurs with shortening and anterior rotation of the distal fragment. This results in scapular malalignment, which has been documented clinically as scapular winging. However, to our knowledge, this scapular malalignment has never been quantified radiographically. The purpose of our study was to quantify the radiographic parameters in patients with symptomatic midshaft clavicle malunions demonstrating scapular winging.

Fourteen patients with symptomatic midshaft clavicle malunions demonstrating scapular winging of the affected shoulder were identified. Each patient underwent CT scanning of both clavicles and scapulae. A standardised CT protocol was used for each patient. Multiple measurements were used to document the clavicle malunion and scapular malalignment including clavicular length, the distance from the tip of the scapula to the chest wall and to the nearest adjacent spinous process, and the relative height of each scapula on the chest wall. Statistical analysis using the Student t-test was performed.

The mean time from fracture was twenty-nine months. There were eleven males and three females with a mean age of 33.1 years. The mean clavicular shortening was 17mm (P> 0.001). The mean anterior-rotation through the malunion was nine degrees, and showed a trend toward significance (P=0.1). The distal fragment was anteriorly translated 13.5mm (P> 0.001) relative to the opposite normal shoulder. The scapula was displaced laterally 10.3mm (P> 0.001) from the nearest spinous process, superiorly 16.3mm and 12.2mm (P> 0.001) off the chest wall on average compared to the opposite normal shoulder.

Patients with symptomatic clavicle malunions often complain of periscapular pain, and winging of the scapula has been noted in such individuals. Ours is the first study to document and quantify scapular malalignment in this clinical setting. Since most shoulder musculature is scapular based, identification and quantification of scapular malalignment may have important ramifications in decision-making regarding treatment of clavicle fractures and malunions.

M. Skutek R. Bourne A. Burns S. Kearns G. Krishna C. Rorabeck

The purpose of this study was to analyse the twenty to twenty-five year outcomes of one hundred and ninetyfive cemented, matte finish, HD-2 THRs performed in one hundred and sixty-six patients with osteoarthritis of the hip by two surgeons.

The one hundred and ninety-five THRs (one hundred and sixty-six patients) were followed prospectively by clinical assessment using the Harris Hip Score (HHS) and radiographic analysis.

One hundred and forty-nine patients (90%) died with their implant still functioning or still had a successful implant at twenty to twenty-five years follow-up. Ten patients (6%) underwent a revision for aseptic loosening of the acetabular (n=2, 1.2%) or femoral (n=4, 2.4%) component, or both (n=4, 2.4%), that was related to wear-induced osteolysis. 7 (4.2%) patients (eight hips) were lost to follow-up. The mean HHS at the latest follow-up (twenty to twenty-five years) was 88±9. Radiographically, twenty-nine (85%) of the acetabular components were well fixed and four (12%) were probably or possibly loose. Two hips (6%) had probable or possible loosening of the femoral component. At twenty five years, the calculated cumulative survival rate (Kaplan-Meier method) revealed excellent results for revisions (83%±6, any cause) and aseptic loosening (86%±6, femoral component, 93%±3, acetabular component).

The surviving patients had a good mean follow-up and radiographic fixation, proving the exceptional long-term success of this implant.

R.W. McCalden R. B. Bourne K. Charron D. Chess S. J. MacDonald C. H. Rorabeck R.W. McCalden

This study reports on the clinical and wear performance of a prospective randomised controlled trial comparing highly cross-linked (XLPE) to conventional polyethylene (PE) in total hip arthroplasty at five years minimum follow-up.

One hundred patients enrolled in a prospective randomised controlled trial received identical hybrid total hip arthroplasties with the exception of the polyethylene insert. Fifty patients received a PE liner (2.5 MRads; gamma-in-nitrogen sterilization) and fifty patients received a XLPE liner (10Mrads; gas-plasma sterilization). Clinical outcomes were determined using Harris Hip, WOMAC and SF-12 scores by an independent study nurse. Femoral head penetration rates were determined using a validated radiographic technique (Hip Analysis Suite based on radiographs at six weeks, one year and yearly post-operatively. Linear regression analysis was performed for both the entire polyethylene groups and on each patient, where the slope represents the steady state head penetration rate (after bedding in) from one to five years follow-up.

None of the patients were lost to follow-up, however, nine patients were deceased before their five year follow-up. Two patients have been revised for loose stems. At average follow-up of 6.0 years (range 5.1–6.8 years), there were no differences in Harris Hip, WOMAC or SF-12 scores. XLPE had a significantly lower (p= 0.03) steady-state head penetration rate of 0.018 mm/year compared to 0.050 mm/year for XLPE (approximately 64% reduction). Analysis of individual patient’s head penetration rates demonstrated a similar significantly lower rate with XLPE (0.004 ± 0.067 mm/year) compared to PE (0.045 ± 0.083 mm/year). Interestingly, when examined by gender, the male PE group had a significantly higher head penetration rate (0.081 ± 0.084 mm/year) than both the male and female XLPE (−0.013 ± 0.104, 0.011 ± 0.074 mm/year, respectively).

At minimum five years follow-up, there were no clinical differences between groups. After bedding-in, there was a significant lower head penetration rate with XLPE compared to PE. Thus, mid-term follow-up appears to demonstrate a significant wear reduction (based on head penetration rates) afforded by first generation XLPE. Long-term follow-up is required to demonstrate the clinical benefit of this new material.

C.J.H. Veillette MN Rochester M. D. McKee L. Wild

We conducted a prospective randomised controlled trial to compare functional outcomes, complications and reoperation rates in elderly patients with displaced intra-articular distal humerus fractures treated with open reduction internal fixation (ORIF) or primary semi-constrained total elbow arthroplasty (TEA).

Twenty-one patients were randomised to each treatment group. Two patients died prior to follow-up and were excluded from the study. Mayo Elbow Performance Score (MEPS) and Disabilities of the Arm, Shoulder and Hand (DASH) scores were collected at six weeks, three months, six months, twelve months and two years. Complication type, duration, management, and treatment requiring reoperation were recorded.

Five patients randomised to ORIF were converted to TEA intraoperatively because of extensive comminution and inability to obtain fixation stable enough to allow early ROM. This resulted in fifteen patients (three male, twelve female) with an average age of seventy-seven years in the ORIF group and twenty-five patients (two male, twenty-three female) with an average age of seventy-eight in the TEA group. MEPS was significantly improved at three months (82 vs 65, p=0.01), six months (86 vs 66, p=0.003), twelve months (87 vs 72, p=0.03) and two years (86 vs 73, p=0.04) in patients with TEA compared with ORIF. DASH scores showed a significant improvement for TEA compared with ORIF between six weeks (43 vs 77, p=0.02) and six months (31 vs 50, p=0.01) but not at twelve months (32 vs 47, p=0.1) and two years (34 vs 38, p=0.6). Reoperation rates for TEA (3/25) and ORIF (4/15) were not statistically different (p=0.2).

TEA for the treatment of comminuted intra-articular distal humeral fractures provides improved functional outcome compared with ORIF.

A. Manjoo A. Badhwar A. Bihari D. Sanders

Elevated intracompartmental pressure (ICP) results in muscle damage. Previous studies identified severe inflammation associated with elevated ICP. This study was designed to determine whether indomethacin, a potent anti-inflammatory agent, reduces muscle damage secondary to elevated ICP. We hypothesised that administration of indomethacin reduces muscle damage from elevated ICP.

Sixteen adult Wistar rats were randomised to four groups. In group One (control), no intervention occurred. Group Two (indo) rats were administered indomethacin (12mg/kg) with no elevation of ICP. Group Three (CS) rats had elevated ICP (30–40mmHg X 45 minutes) using saline injection. Group Four rats (CS/indo) had elevated ICP and indomethacin administration. After forty-five minutes, hindlimb fasciotomy was performed. The extensor digitorum longus muscle was reflected onto an intravital microscope. Capillary perfusion was measured by comparing the number of continuously perfused capillaries to intermittent and non perfused capillaries. Inflammation was determined using the number of activated (rolling and adherent) white blood cells. Muscle cell damage was measured using differential fluorescent staining. Perfusion, inflammation, and muscle damage were compared in all four groups using a one-way ANOVA (p< 0.05).

Perfusion: Indomethacin treatment (CS/indo) increased the proportion of intermittently perfused capillaries (39.1 ± 2.2 vs 30.3 ± 2.7) and decreased nonperfused capillaries (38.4 ± 1.8 vs 50.1 ±2.5) compared to CS (p=0.0002). Control and indo groups demonstrated more continuously perfused capillaries compared to CS or CS/indo groups (p< 0.0001). Muscle damage: Indomethacin treatment of elevated ICP reduced the proportion of damaged cells from 0.20 ± 0.14 (CS) to 0.01 ± 0.0.005 (CS/indo, p< 0.0001). There were no differences between CS/indo, control, or indo groups. Inflammation: CS and CS/indo groups demonstrated greater inflammatory activation compared to control and indo groups (p< 0.001). There were no differences in inflammatory activation between CS and CS/indo (p> 0.05).

Treatment of elevated ICP with indomethacin improved microvascular perfusion and reduced cell damage. The protective mechanism of indomethacin is unknown, but may be related to an anti-oxidative and vasodilatory effect. Treatment of elevated intracompartmental pressure with indomethacin dramatically reduces muscle damage and may have important future clinical benefit.

R. Bicknell P. Boileau B.J. Burger C. Chuinard J.S. Coste W.J. Willems

The complications of prostheses for fractures of the proximal humerus are understudied because the experience of each shoulder surgeon is limited and a standardised registration protocol is not yet available. A prospective study on complications in shoulder arthroplasty for fracture is, therefore, essential to explore variables that influence outcome. The purpose of this study is to report our experience with complications following arthroplasty for proximal humeral fractures.

In a multicenter study, four hundred and six patients treated with arthroplasty for proximal humeral fracture were prospectively followed during a nine year period; three hundred patients with a minimum of two years follow-up, at an average of forty-five months (range, 24–117), were available for review. Objective results were graded with the Constant score and range of motion. Subjective results were reported according to patient satisfaction.

At follow-up, the average Constant score was fifty-four points (range, 14–95) and active forward elevation was 103° (range, 10°–180°). Eighty-one percent of patients were satisfied or very satisfied. We observed a 59% rate of late (after three months) complications, including a high rate of tuberosity-related complications (72% malunion or nonunion). Initial tuberosity malposition was present in 35% of the patients. Secondary migration despite initial good positioning was observed in 24%.

Tuberosity complications were associated with poor final Constant score, poor range of motion and shoulder pain (p=0.001 for all items). A re-operation was performed in 5.3% of the cases. Patients who were mobilised according to the ‘early passive motion’ concept had double the incidence of secondary tuberosity migration, compared to those that were initially immobilised (14% versus 27%, p=0.004). Tuberosity complications are the most frequent late complication and they are associated with poor functional results. It is, therefore, incumbent upon the surgeon to maximise healing with adequate fixation of the tuberosities, followed by sufficient immobilization.

A. Alturki Gwendolyn Dobbin R.K. Leighton M.C. McCaffrey Kelly Trask

The ideal bearing surface for total hip arthroplasty is still an area of debate.Increasing numbers of total hip replacements are being done in the younger patient population.Ceramic-on-ceramic bearings have gained popularity due to their low wear rate.However, ceramic fractures with subsequent catastrophic failures have been reported. This study reports on early results of ceramic-on-ceramic total hip replacements.

This is a study analyzing a prospectively collected data for seventy-five ceramic-on-ceramic total hip replacements with minimum follow up of eighteen months. Average age at time of surgery was forty-seven years. This study focused on the complications of this ceramic population. Complications included: One posterior dislocation, two intra-operative calcar fractures that needed wiring, one intra-operative fracture of the acetabular liner, two cases of impingement (one which resulted in a revision), and one periprosthetic fracture. The two patients that required further surgery were the periprosthetic fracture after a fall and one for component impingement. No revisions were performed for loosening or catastrophic failures. No wear, loosening, or osteolysis was seen on radiographs. The SF-12, WOMAC, and Harris Hip scores were not significantly different from other reported hip series.

Ceramic-on-ceramic bearing surfaces in total hip arthroplasty are a safe option with outcome equivalent to standard THR in the short term. Ceramic Hips may provide a more durable prosthesis, especially in young and active patients. Intra-operative technical guidelines that may enhance the quality of the results will be presented and fully disclosed.

P.R. Kim

Metal on metal hip articulations are associated with the release of cobalt and chromium ions. There are few published reports of these levels following hip resurfacing arthroplasty. This study was undertaken to determine cobalt and chromium ion levels following hip resurfacing arthroplasty.

Ninety-one patients were prospectively entered in a study assessing ion levels following hip resurfacing arthroplasty. Serum, erythrocyte and urine cobalt and chromium levels were measured. Samples were collected preoperatively then at three months, six months and yearly thereafter. Each sample was analyzed with an ICPMS assay machine.

Preoperatively the median values for serum, erythrocyte and urine cobalt and chromium levels were all within the normal range. Median serum cobalt levels increased from baseline (0.1 ug/l) to 1.1 ug/l at one year and 1.6 ug/l at two years. Median serum chromium levels increased from baseline (0.2 ug/l) to 1.9 ug/l at one year and 3.3 ug/l at two years. Median erythrocyte cobalt levels increased from baseline (0.1 ug/l) to 1.0 ug/l at one year and 1.3 ug/l at two years. Median erythrocyte chromium levels increased slightly from baseline (1.0 ug/l) to 1.2 ug/l at both one and two year follow-up. No correlation was seen between ion levels and patient activity, implant position, clinical scores or BMI. No clinical effects of elevated ions were observed. Outliers of either cobalt or chromium were seen in twelve patients (13%) in the series.

Hip resurfacing arthroplasty is associated with significant elevations of cobalt and chromium ions. An increase in serum levels of both cobalt and chromium has been noted at two years. This trend also occurs with erythrocyte cobalt but not with erythrocyte chromium. There is a close correlation between serum and erythrocyte cobalt levels but not between serum and erythrocyte chromium levels. We recommend using serum cobalt and serum chromium measurements as a standardised method of ion analysis following metal on metal hip replacement. This allows for capture of maximal levels of both ions in vivo. Further study is required to determine if any clinical effect will be seen as a result of these elevated ions.

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P.R. Kim P. Beaule A. Conway M. Dunbar Y. Laflamme

Hip resurfacing arthroplasty has become a popular treatment option for younger active patients. The early published results from designing surgeons/centers have been favourable. We undertook a prospective multi-center trial to determine the outcome of hip resurfacing arthroplasty at independent centers. The clinical, radiographic and functional results were assessed.

A prospective IRB approved study was initiated in July 2003 to assess the outcome of hip resurfacing arthroplasty using a contemporary design implant. (Conserve Plus - Wright Medical Technology) Disease specific (Harris Hip Score/WOMAC) and global (Rand self assessment index) outcome measures were used. Radiographs were reviewed for component position and migration as well as any signs of lysis or loosening. Complications and re-operations were recorded.

A total of one hundred and eighty-eight patients have been enrolled in the study to date. One hundred and four patients have a minimum one year follow-up and forty-six patients have a minimum two year follow-up. Mean Harris Hip Scores (pre-op, one year, two years) were fifty-five, eighty-nine and ninety-one. Mean WOMAC pain scores were forty-seven, ninety and ninety. Mean WOMAC stiffness scores were forty, seventy-eight and eighty-two. Mean WOMAC function scores were forty-six, eighty-seven and eighty. RAND physical function mean scores were thirty-three, seventy-six and seventy-six and the RAND physical limitations mean scores were nineteen, sixty-seven and seventy-five. Radiographic analysis showed average cup abduction to be forty-six degrees (range twenty-six to sixty-three). Average femoral stem position was one hundred and thiry-eight degrees (range one hundred and eighteen to one hundred and fifty-seven). Nine patients have been revised to date (4.8%). Four for acetabular loosening, two for neck fracture, one for femoral loosening, one for impingement and one for persistent pain. There have been eight other patients requiring re-operation without revision. Medical complications occurred in fifteen patients.

Early results have demonstrated a good return of function in patients with hip resurfacing arthroplasty. A high early revision rate (4.8%) was seen in our study. Technical factors appear to be the main contributor to the high early complication rate. Hip resurfacing is associated with a steep learning curve. We continue to utilise hip resurfacing in select patients but recommend caution for those who are new to the technique.

S. MacDonald R. B. Bourne D. Chess R. W. McCalden C. H. Rorabeck A. Thompson

We performed a prospective, randomised, blinded clinical trial comparing metal versus polyethylene bearing surfaces in patients receiving a THA.

Forty-one patients were randomised to receive a metal (twenty-three) or a polyethylene (eighteen) insert with identical femoral and acetabular components. The metal bearing was a 28mm low carbon on high carbon couple. Patients were evaluated pre-operatively, at three, six, twelve months and annually thereafter, including an evaluation of erythrocyte and urine cobalt, chromium, and titanium, outcome measures (WOMAC, SF-12, Harris Hip Score) and radiographs.

No patients were lost to follow-up. At an average 7.2 (range 6.1 – 7.8) years follow-up there were no differences in any outcome measures or radiographic findings. Patients receiving metal liners had significantly elevated metal ion measurements. At most recent follow-up, compared to the polyethylene control group, patients receiving a metal on metal bearing had erythrocyte cobalt levels were eleven times elevated (median 1.4 μg/L (metal) vs 0.12 μg/L (poly), p< .001). Urine cobalt levels were thirty-nine times elevated (median 11.4 μg/L/day (metal) vs 0.29 μg/day (poly), p< .001) and urine chromium levels were twenty-eight times elevated (median 4.75 μg/day (metal) vs 0.17 μg/day (poly), p< .001). Additionally the metal ion levels reached an early steady state level and did not decrease over time. (Erythrocyte Co (μg/L): 1.29 (6 mos), 1.20 (1 yr), 1.0 (2 yr), 1.10 (3 yr), 1.35 (4 yr), 1.40 (5 yr)).

Both cobalt and chromium ion measurements were significantly elevated in the blood and urine of the patients randomised to receive the metal on metal THA at all time intervals. Contrary to previous reports, in 34% of patients with a metal liner, metal ion (erythrocyte cobalt) elevation was still increasing at latest follow-up, and in the overall metal on metal patient cohort, metal ion median levels were not decreasing over time. As in polyethylene wear data, metal ion results are not necessarily generalizable, but are bearing design specific.

J. Antoniou O.L. Huk F. Mwale A. Petit D. J. Zukor

Hip surface replacement is an alternative for young patients considered for hip replacement. The in vivo release of ions from these surfaces has yet to be well evaluated. In the present study, we compared the concentrations of metal ions in blood of patients with hip surface replacement and metal-on-metal (MM) total hip arthroplasty (THA).

Blood was collected six months and one year after implantation time into Sarstedt Monovette® tubes for trace metal analysis from patients having Articular Surface Replacement (ASR®, DePuy Orthopaedics; n=61), 28 mm-head MM THA (n=18), and 36 mm-head MM THA (n=25). The concentrations of cobalt (Co), chromium (Cr), and molybdenum (Mo) were analyzed by inductively coupled plasma-mass spectroscopy (ICP-MS). Since metal ions are potent inducers of oxidative stress, total antioxidant, peroxide, and nitrotyrosine levels (oxidative stress markers) were also measured in plasma of the patients.

The median Co and Cr levels progressively and significantly increased in the three groups during the first year post-operation (compared to patients without hip bearings (n=25)). After six months, the levels of Co and Cr were significantly higher in patients with ASR and 28 mm MM THA than in patients with 36 mm MM THA. There was no difference after one year. The level of activity, as measured by the UCLA activity score, was higher in ASR patients than in 28 and 36 mm MM THA after one year. No differences were observed for Mo levels in these patients when compared to our control group. There was no increase of oxidative stress marker levels in patients with ASR and 36 mm MM THA and no correlation between the concentrations of Co and Cr ions and the levels of oxidative stress markers.

Our results show that, at one year post-operation, the concentration of ions in patients with ASRs is similar than those in patients with MM THAs. Moreover, results suggest that metal ions liberated from MM bearings do not induce damage to macromolecules by oxidative stress in plasma of patients. Longer follow-ups are still required to characterise the concentration of ions in ASR and to determine conclusively the effects of elevated circulating ions.

D. Rouleau B. Benoit G. Berry E. Harvey G. Y. Laflamme R. Reindl

Plate fixation of the proximal humerus fractures may now be more desirable with the use of a biological approach by limiting surgical insult and allowing accelerated rehabilitation by a solid fixation. To evaluate the safety and efficacy of minimally invasive plating of the proximal humerus using validated disease-specific measures.

During a period of one year, thirty patients were operated with use of the LCP proximal humerus plate (Synthes) through a 3cm lateral deltoid splitting approach and a second 2 cm incision at the deltoid insertion. The axillary nerve was palped and easily protected during insertion. Only two-part (N=22) and three-part impacted valgus type (N=8) were included in this study since they can be reduced indirectly thru this percutaneous technique. The average follow-up was thirteen months (eight to twenty months). All patients had the Constant and DASH evaluations.

All fractures healed within the first six months with no loss of correction. The surgical technique was found easy by all surgeons, the axillary nerve was palpated and protect with this new technique. No infection or avascular necrosis were seen. No axillary nerve deficit was identified. At the last follow-up (average nineteen months, twelve months minimum), the median Constant score was sixty-eight points, with an age ajusted score of seventy-six. The mean DASH score was twenty-seven points. Only age was independently predictive of both the Constant and DASH functional scores. Patients improved until one year of follow up.

Percutaneous insertion of a locking proximal humerus plate is safe and produces gives good early functional and radiologic outcomes. Recuperation from a proximal humerus fracture can be seen until one year.

J. L. Howard J. Agel D. P. Barei S. K. Benirschke S. E. Nork

This prospective observational study was designed to report the soft tissue complications after fixation of tibial plafond fractures in an effort to challenge the current recommendation that a seven centimeter skin bridge represents the minimum safe distance between surgical incisions. Our hypothesis was that many of the skin bridges would be less than seven centimeters and that this would not result in an increased incidence of wound complications.

All injuries received surgical treatment using a minimum of two surgical approaches for the tibial plafond and the associated fibula fracture (if applicable). Forty-two adult patients with forty-six tibial plafond fractures were enrolled in the study between July 1, 2004 and Dec 30, 2005. There were 1 A1, 3 B1, 2 B3, 6 C1, 6 C2 and 28 C3 fractures. Forty-four plafond fractures had an associated fibular fracture. There were thirty-six closed and ten open fractures. High energy injuries were managed using a two staged approach consisting of fibular ORIF through a posterolateral approach combined with spanning external fixation, followed by tibial ORIF when soft tissue swelling subsided (forty-four fractures). The surgical approaches used, the length of the incisions, the distance between the incisions (size of the skin bridge), and the overlap between the incisions was recorded. The surgical wounds were followed until healing and for a minimum of three months.

Two surgical approaches were used in thirty-two fractures and three approaches were used in fourteen. These one hundred and six surgical incisions produced sixty skin bridges. The approaches used included pos-terolateral (forty-four), anterolateral (thirty-nine), medial (eleven), anteromedial (eight), and posteromedial (four). The mean skin bridge size was 5.9 cm. Only 15% of the skin bridges were > 7 cm, while 70% were 5–7 cm, and 15% were < 5 cm. The mean overlap between incisions in the study was 7.9 cm. One hundred two incisions healed uneventfully. Healing of two anterolateral incisions was complicated by eschars that resolved with local wound care. One posterolateral fibular incision failed to heal until the fibular plate was removed. One patient required subsequent surgical procedures for infection.

Despite a measured skin bridge of less than seven centimeters in 85% of instances, the soft tissue complication rate was low in this group of patients. With careful attention to soft tissue management and surgical timing, incisions for plafond fractures may be placed less than seven centimeters apart, allowing the surgeon to optimise exposures based on the pattern of the injury.

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A. Manjoo D. Sanders C. Tieszer

Screw fixation of the injured syndesmosis restores stability, but may reduce ankle motion. We wished to determine whether functional and radiographic results are improved by removal of syndesmosis screws. In addition, we studied whether large fragment screws have an advantage compared to small fragment screws. We hypothesised that retained intact syndesmosis screws are detrimental to ankle function.

One hundred and seven adults with ankle fractures requiring syndesmosis screw fixation between 2001 and 2005 were retrospectively studied. Indications for syndesmosis fixation were a positive intraoperative external rotation stress test or inadequate lateral column buttress. Weight bearing was encouraged six weeks postoperatively. Syndesmosis screws were only removed for tenderness, prominence or ankle dorsiflexion < 0.05.

The LEM score for patients with intact screws was 70 ± 26 compared with 85 ± 20 for broken, loosened or removed screws (p=0.05). The OM score for patients with intact screws was 48 ± 36 compared with 63 ± 27 for broken, loosened or removed screws (p=0.12). There was no difference in outcome comparing broken, loosened, and removed screws. The tibiofibular clear space for intact screws was 3.3 ± 1.3 compared with 4.1 ± 1.7 for removed, broken or loosened screws (p=0.02). There was no difference in outcome comparing large and small fragment screws.

Patients with broken, loosened or removed syndesmosis screws have better functional outcome compared to intact screws. The syndesmosis allows fibular rotation, shortening and translation during gait; the presence of an intact syndesmosis screw may restrict this motion. There was no disadvantage to leaving broken or loosened screws in-situ.

D.G. Allan B. W. Dyrstad J. C. Milbrandt B. K. Parsley

Metal-on-metal (MOM) hip resurfacing devices are known to release metal ions locally and into the systemic circulation. Previous studies suggest that larger prosthetic head size will correlate to reduced wear properties and may result in lower systemic release of metal ions. This project assessed the effect of femoral head size on serum cobalt (Co) and chromium (Cr) levels in subjects after unilateral hip resurfacing with the Cormet 2000 prosthesis.

We prospectively collected patient characteristics, outcome, and serum samples from device implanted subjects at six months, one, two, and three years following surgery. Serum Co/Cr levels were determined using high-resolution inductively coupled plasma mass spectrometry. Students t-test was used to compare ion levels in two groups based on femoral head size.

Thirty-five subjects (twenty male) were followed. Co/Cr levels were increased at all time points when compared to control levels. A significant negative correlation was observed between Co and Cr levels and femoral head size. Co/Cr levels in subjects with larger femoral heads were significantly lower when compared to those implanted with smaller heads (Co, −35.8%; Cr, −33.0%). This correlated with significantly higher Co/Cr levels in females versus males, with females receiving significantly smaller heads on average.

Elevated serum Co/Cr levels were observed at all time points following implantation and in females and in subjects with femoral heads.

C. Kean T.B. Birmingham J. Garland J. R. Giffin T. R. Jenkyn I. C. Jones

Previous research suggests knee joint moments and muscle activity during walking are altered in patients with anterior cruciate ligament (ACL) deficiency and in patients with medial compartment knee osteoarthritis (OA). The objective of this study was to compare knee joint flexion and adduction moments and the extent of quadriceps-hamstring muscle co-contraction before and one year after combined simultaneous ACL reconstruction and high tibial osteotomy (HTO).

Eighteen patients (three females, fifteen males; age = 40 ± 8 yrs.; BMI = 28.8 ± 5.77) with ACL deficiency and OA affecting primarily the medial compartment of the knee underwent ACL reconstruction (hamstring autograft) and medial opening wedge HTO procedures during a single operation. All patients completed pre-operative and one-year postoperative quantitative gait assessments. Three-dimensional kinetic and kinematic data were collected during self-paced walking and used to calculate the peak external flexion and adduction moments about the knee. Electromyographic (EMG) activity was collected from the hamstrings and quadriceps and used to calculate the co-contraction ratio. Peak moments and co-contraction ratios were compared pre and postoperatively using paired t-tests.

The peak knee flexion moment decreased from 2.31 ± 1.14 to 1.33 ± 0.73 %BW*ht (p=0.001); mean decrease = 0.98 %BW*ht (95%CI: 0.49–1.47). The peak knee adduction moment decreased from 2.81 ± 0.62 to 1.69 ± 0.61 %BW*ht (p< 0.001); mean decrease = 1.12 %BW*ht (95% CI: 0.80–1.43). The quadriceps-hamstring co-contraction ratio decreased from 0.82 ± 0.14 to 0.72 ± 0.18 (p=0.056); mean decrease = 0.10 (95% CI: −0.003 – 0.21).

The present findings suggest that combined simultaneous ACL reconstruction and HTO significantly decreases knee flexion and adduction moments during walking. Although the present findings suggest that the quadriceps-hamstring co-contraction ratio also decreases, future research with more patients is required to confidently evaluate potential changes in muscle activity. These findings are consistent with an overall reduction in dynamic knee joint load.

S. D. M. Wotherspoon J. R. Giffin P. J. Fowler R. B. Litchfield M. Neligan K. R. Willits

The purpose of our study is to determine if hamstring autograft size can be predicted preoperatively. We will define a relationship between patient body size (BMI, height, and weight) and harvested graft size, as well as define a relationship between the preoperative MRI cross-sectional area (CSA) of hamstring tendons and harvested graft size. This information will be useful as a tool for preoperative planning in graft choice selection.

The pre-operative MRIs of one hundred and four patients (62M, 42F) who underwent ACL reconstruction using hamstring autografts were analyzed. Cross-sectional area (CSA) of the ST and G was measured on a single axial MRI image at the level of the knee joint. Combined CSA of both tendons was then compared to the diameter of the four-strand hamstring autograft measured intra-operatively. Patient BMI, height and weight was also compared to intraoperative hamstring autograft size. Linear regression analysis was then performed to define the relationship and predictive value of body size on graft diameter.

Mean graft size was 7.4mm (range 6 – 9). Average graft size for men and women, 7.6mm and 7.1mm, respectively. Predicting graft size from BMI: r= 0.29, R2= 0.08. Predicting graft size from height: r= 0.52, R2= 0.27. Predicting graft size from weight: r= 0.5, R2= 0.25. On preoperative MRI, the mean CSA of ST and G was 9.8mm2 (range 5.4 – 17.7) and 4.5mm2 (range 1.8 – 9.4) respectively, with a total CSA of 14.3mm2 (range 8.4 – 25). If the total CSA was greater than 12mm2, a graft of 7.0mm or greater could be predicted 93% of the time, with sensitivity and specificity, 78% and 76%, respectively, and a LR of 3.25.

Body size is a poor predictor of hamstring graft size in ACL reconstruction, and therefore a large patient does not always provide a large graft from harvested hamstring tendons. MRI assessment of hamstring tendons can be a useful tool for preoperative planning, providing a strong predictive value of graft size from a simple calculation.

S. Ward B. Escott D. Beaton E. Kovacs N. Aslam R. Abughaduma M. McKee J. Waddell H. Kreder E. Schemitsch