Osteochondral (OC) defects of the knee are associated with pain and significant limitation of activity. Studies have demonstrated the therapeutic efficacy of mesenchymal stem cell (MSC) therapies in treating osteochondral defects. There is increasing evidence that the efficacy of MSC therapies may be a result of the paracrine secretion, particularly exosomes. Here, we examine the effects of MSC exosomes in combination with Hyaluronic Acid (HA) as an injectable therapy on functional osteochondral regeneration in a rabbit osteochondral defect model.

Exosomes were purified from human MSC conditioned medium by size fractionation. A circular osteochondral defect of 4.5 mm diameter and 2.5 mm depth was surgically created in the trochlear grooves of 16 rabbit knees. Thereafter, eight knees received three weekly injections of 200 µg of exosomes in one ml of 3% HA, and the remaining eight knees received three weekly injections of one ml of 3% HA only. The rabbits were sacrificed at six weeks. Analyses were performed by macroscopic and histological assessments, and functional competence was analysed via Young Modulus calculation at five different points (central, superior, inferior, medial and lateral) of the repaired osteochondral defect site.

MSC exosomes displayed a modal size of 100 nm and expressed exosome markers (CD81, TSG101 and ALIX). When compared to HA alone, MSC exosomes in combination with HA showed significantly better repair histologically and biomechanically. The Young Modulus was higher in 4 out of the 5 points. In the central region, the Young Modulus of MSC exosome and HA combination therapy was significantly higher: 5.42 MPa [SD=1.19, 95% CI: 3.93–6.90] when compared to HA alone: 2.87 MPa [SD=2.10, 95% CI: 0.26–5.49], p < 0 .05. The overall mean peripheral region was also significantly higher in the MSC exosome and HA combination therapy group: 5.87 MPa [SD=1.19, 95% CI: 4.40–7.35] when compared to HA alone: 2.70 MPa [SD=1.62, 95% CI: 0.79–4.71], p < 0 .05. The inferior region showed a significantly higher Young Modulus in the combination therapy: 7.34 MPa [SD=2.14, 95% CI: 4.68–10] compared to HA alone: 2.92 MPa [SD=0.98, 95% CI: 0.21–5.63], p < 0.05. The superior region showed a significantly higher Young Modulus in the combination therapy: 7.31 MPa [SD=3.29, 95% CI: 3.22–11.39] compared to HA alone: 3.59 MPa [SD=2.55, 95% CI: 0.42–6.76], p < 0.05. The lateral region showed a significantly higher Young Modulus in the combination therapy: 8.05 MPa [SD=2.06, 95% CI: 5.49–10.61] compared to HA alone: 3.56 MPa [SD=2.01, 95% CI: 1.06–6.06], p < 0.05. The medial region showed a higher Young Modulus in the combination therapy: 6.68 MPa [SD=1.48, 95% CI: 4.85–8.51] compared to HA alone: 3.45 MPa [SD=3.01, 95% CI: −0.29–7.19], but was not statistically significant. No adverse tissue reaction was observed in all the immunocompetent animals treated with MSC exosomes.

Three weekly injections of MSC exosomes in combination with HA therapy results in a more functional osteochondral regeneration as compared to HA alone.

Objectives

Long bone defects often require surgical intervention for functional restoration. The ‘gold standard’ treatment is autologous bone graft (ABG), usually from the patient’s iliac crest. However, autograft is plagued by complications including limited supply, donor site morbidity, and the need for an additional surgery. Thus, alternative therapies are being actively investigated. Autologous bone marrow (BM) is considered as a candidate due to the presence of both endogenous reparative cells and growth factors. We aimed to compare the therapeutic potentials of autologous bone marrow aspirate (BMA) and ABG, which has not previously been done.

Recurrent patellar instability is common in young and active patients. Medial patellofemoral ligament (MPFL) reconstruction with a single bundle hamstring graft is one method of surgical treatment for this problem. This is a retrospective case series of patients who underwent MPFL reconstruction by a single specialist knee surgeon between January 2009 and July 2014. Data was collected prospectively for the purpose of service evaluation. Recorded data included gender, age, length of rehabilitation, complications, Knee Injury and Outcome Score (KOOS) and International Knee Documentation Score (IKDC). Data is expressed as mean (range). 108 knees (103 patients) were identified (56 female, 52 male) with a mean age of 24.5 years (12–58). Mean length of rehabilitation was 3.2 months (0–11 months). Three patients required further revision surgery for recurrent instability. KOOS and IKDC scores improved from 44 (4–86) and 38 (2–81), respectively before surgery, to 77 (49–100) and 69 (37–95) after rehabilitation. MPFL reconstruction with a single bundle hamstring graft produces a marked improvement in knee function with a low recurrence of instability.

Introduction

High flexion knee arthroplasties have been designed to allow up to 155 degrees flexion and enable high flexion activities such as kneeling and squatting. To date randomised controlled trials have shown no difference in range of movement (ROM) between high flexion and standard designs.

Anterior cruciate ligament (ACL) injuries are being seen with increasing frequency in children. Treatment of the ACL deficient knee in skeletally immature patients is controversial.

To determine the outcome of anatomic transphyseal ACL reconstruction in tanner stage 1 and 2 patients with open growth plates at a minimum of 2 years after surgery.

Between 2007–2008, 16 prepubescent skeletally immature patients underwent anatomic transphyseal ACL reconstruction using soft tissue grafts. All patients were tanner stage 1 and 2 and all had open growth plates. Outcomes were assessed at a minimum of 2 years after surgery and included: limb alignment, limb length, instrumented testing with KT-1000 and International Knee Documentation Committee (IKDC) score.

Mean age at the time of surgery was 12 years (8–14). Graft choices included: living-related donor hamstring tendon allograft (n=14), hamstring tendon autograft (n=1) and fresh frozen allograft (n=1). Mean IKDC subjective score was 96 (84–100). Sixty-two percent of patients had <3mm side-to-side difference on instrumented KT-1000 testing and 88% had a negative pivot shift. At 2 years after surgery, all patients had returned to strenuous activities and normal or nearly normal overall IKDC score was documented in 94% of patients. There were no cases of limb malalignment or growth arrest.

We present a large series of anatomic transphyseal ACL reconstruction in tanner stage 1 and 2 patients with open growth plates at a minimum of 2 years following surgery. Excellent clinical outcomes were obtained with high levels of return to desired activities. Importantly, no growth disturbances were seen in this series of patients.

Background

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Introduction

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Stable ankle fractures can be successfully treated non-operatively with a below knee plaster cast. In some European centres it is standard practice to administer thromboprophylaxis, in the form of low molecular weight heparin, to these patients in order to reduce the risk of deep venous thrombosis (DVT).

The aim of our study was to assess the incidence of DVT in such patients in the absence of any thromboprophylaxis. We designed a prospective study, which was approved by the local ethics committee. We included 100 consecutive patients with ankle fractures treated in a below knee plaster cast. At the time of plaster removal (6 weeks), patients were examined for signs of DVT. A colour doppler duplex ultrasound scan was then performed by one of the two experienced musculoskeletal ultrasound technicians.

We found that 5 patients developed a DVT. Two of these were above knee, involving the superficial femoral vein and popliteal vein respectively. The other three were below knee. None of the patients had any clinical symptoms or signs of DVT. None of the patients developed pulmonary embolism. Of these five patients, four had some predisposing factors for DVT.

The annual incidence of DVT in the normal population is about 0.1%. This can increase to about 4.5% by the age of 75. DVT following hip and knee replacement can occur in 40-80% of cases. Routine thromboprophylaxis may be justified in these patients. However, with a low incidence of 5% following ankle fractures treated in a cast, we believe that routine thromboprophylaxis is not justified.

Purpose: Congenital idiopathic clubfoot is the most common congenital deformity in children and can be a major cause of disability for the child as well as an emotional stress for the parents. The Ponseti method of club-foot correction, consisting of serial manipulations and casting, is now the gold standard of treatment. It has traditionally been described using plaster of Paris (POP) above-knee casts, which are affordable, stiff, and easily moldable. Recently, semi-rigid fiberglass softcast (FSC, 3M Scotchcast) has grown in popularity due to ease of removal, durability, lighter weight, better appearance, ease of cleaning, and water resistance. There are currently no randomized controlled trials to prove its efficacy with respect to POP. The purpose of this study was to determine the influence of choice of cast material on the correction of congenital idiopathic clubfeet using the Ponseti method.

Method: A prospective, randomized controlled trial. Based on the results of a pilot study performed at our centre, a sample size of 30 patients was determined to be appropriate. Thirty consecutive patients presenting with congenital idiopathic clubfoot were randomized into POP and FSC groups prior to commencement of treatment with the Ponseti Method. Clubfeet secondary to non-idiopathic diagnoses were excluded. The Pirani classification was used to determine clubfoot severity (less severe, < =4; severe > 4), and for surveillance during casting. The primary outcome measure was the number of casts required to correct the clubfoot deformities to the point where the foot was ready for a percutaneous tendo-achilles tenotomy (TAL) or when the foot was completely corrected (Pirani=0). Secondary outcome measures include: number of casts by clubfoot severity, ease of cast removal, number of methods needed to remove casts, need for percutaneous tendo-achilles tenotomy.

Results: Of the 30 patients enrolled, 13 (40%) were randomized to POP and 18 (60%) to FSC. No patients were lost to follow-up. In the POP and FSC groups, eight (67%) and 11 patients (61%) underwent a TAL, respectively. In general, there were no differences in the mean number of casts required for clubfoot correction between the two groups (p=0.13). When analyzed by clubfoot severity, the mean number of casts for each material in the less severe group was equal (3 casts). In the severe group, the mean number of casts in the FSC group (6.4 casts) was considerably higher than for the POP group (4.7 casts) but our study was underpowered to verify this result. According to parents, POP was harder to remove than FSC (p< 0.001).

Conclusion: In general, FSC was found to be as efficacious as POP in the correction of idiopathic clubfeet by the Ponseti Method and was the preferred cast material by parents. For stiffer, more severe feet, POP seemed to show a faster correction time than FSC.

Purpose: The management of degenerative arthritis of the knee in the younger, active patient often presents a challenge to the orthopaedic surgeon. Surgical treatment options include: high tibial osteotomy (HTO), uni-compartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The purpose of this study was to examine the long-term survival of closing wedge HTO in a large series of patients 8–19 years after surgery.

Method: The results of 458 consecutive patients undergoing lateral closing wedge HTO for medial compartment osteoarthritis (MCOA) between 1990 and 2001 were reviewed. Between 2008–2009, patients were contacted via telephone and assessment included: incidence of further surgery, Oxford Knee Score, and British Orthopaedic Association (BOA) Patient Satisfaction Scale. Failure was defined as the need for revision HTO or conversion to UKA or TKA. Survival analysis was completed using the Kaplan-Meier method.

Results: We were able to contact 400/458 (87%) patients for follow-up via telephone interview. Five patients (1%) who declined participation were excluded. Fifty-eight patients (13%) were lost to follow-up. Of the 395 patients, 12 (3%) had died of unrelated causes and 124 (31%) required further knee surgery. The remaining 259 (66%) completed the BOA patient satisfaction score and Oxford Knee Score. The probability of survival for HTO at 5, 10 and 15 years was 95%, 79% and 55% respectively. Multivariate regression analysis showed that only age < 50 years (p< 0.001) was associated with significantly longer survival. Mean Oxford Knee Score was 40/48 (range 17–60). Ninety-two percent (239/259 patients) were enthusiastic or satisfied and 90% (234/259 patients) would undergo HTO again at mean 11 years follow-up. Complications included: 5 pulmonary embolisms, 8 deep vein thromboses, 1 non-union, 1 post-operative subarachnoid hemorrhage and 1 transient peroneal nerve palsy.

Conclusion: To our knowledge, we have reported the long-term follow-up of lateral closing wedge HTO in the largest group of patients in the literature. We found that the results of HTO do deteriorate over time but that HTO can be effective for as long as 19 years. In appropriately selected patients and circumstances, HTO gives high patient satisfaction and affords patients unrestricted activity for many years.

High tibial valgus osteotomy is now well established in management of medial knee osteoarthritis. While conventional closing osteotomies are usually within 2 cm of the knee joint, opening wedges typically pivot more distally from the joint line; theoretically the same angular correction will cause greater linear shift of the tibial plateau away from the tibial long axis. We hypothesise that this may lead to an increased incidence of problems with future knee replacement where tibial stem augments are needed, and to evaluate this we used a computerbased templating system with web-based component templates for sizing and implant position planning.

We studied 10 knees that had undergone opening wedge osteotomy. Pre-operative and postoperative mechanical and anatomical axes, and corrections achieved, were measured radiologically. Computer-based knee arthroplasty templating was then performed with the TraumaCad digital templating software (Orthocrat, Israel), using Depuy PFC tibial component templates with 75 mm stem augments. Cases were analysed for impingement of tibial stem augments when added to a well-placed tibial tray, and conversely for the need for tibial tray downsizing to avoid tray overhang if stem augments were placed centrally.

Results: Mean pre-operative mechanical axis was 10.6o varus (1.6o to 22.3o). Mean osteotomy to joint line distance was 25.7mm (21.0mm to 33.1mm). In four knees, the addition of a 75 mm tibial stem augment to a well-placed tibial component caused stem impingement on cortex. In these four cases, central placement of the stem augment in the canal led to medialisation of the tibial component, necessitating downsizing of tibial tray by one to two sizes to avoid medial overhang and resulting in sub-optimal coverage of the cut tibia. These four cases all had valgus corrections of over 11o (11.5o to 19.6o). Conversely the six cases that did not have impingement or sizing problems all had corrections under 9o (3.0o to 8.2o). Our early results suggest that higher degrees of valgus correction with opening wedge osteotomy may lead to problems with future knee replacements requiring tibial stem augments. We are in the process of recruiting more cases to determine threshold levels for different makes and models of implants, using the same templating software system.

Introduction: To quantify the magnitude and incidence of haemodynamic changes that occurs during the fixation of extracapsular proximal femoral fractures when using either intra-medullary or extra-medullary fixation device.

Methods: A prospective group of 31 patients with extra-capsular proximal femoral fractures were randomised to either fixation using an extra-medullary compression hip screw or an intra-medullary hip screw. All patients received a general anaesthetic adhering to a standardised anaesthetic protocol including invasive blood pressure monitoring and arterial blood gas sampling. Trans-oesophageal Doppler probe and monitor was used to record pre-operative hypovolaemia and peri-operative changes in cardiac output, stroke volume and corrected flow time (FTc – a reflection of left ventricular end diastolic pressure) during placement of implants.

Results: 77% of patients were hypovolaemic preoperatively, which was corrected with an average of 439 mls of colloid replacement fluid. Application of the extra-medullary CHS produced no change in haemodynamic function. However on insertion of the IMHS we found a statistically significant reduction in stroke volume, cardiac output and FTc without changes in pulse rate or mean arterial pressure. The changes were transient with normal cardiac function returning by 5 mins post operatively.

Conclusion: The transient fall in cardiac function during insertion of the intramedullary hip screw may be caused by fat embolism entering the venous circulation. As these changes are not detected with standard non-invasive monitoring we would recommend that intramedullary devices be used with caution in elderly patients who tend to have poor physiological reserve.

AIM: To investigate the relationship between patient variables and surgeons’ grade and experience on one hand and re-operation and mortality rates at six months on the other hand.

Method: Seven hundred and sixty-one patients with proximal femoral fractures (PFF) (463 intracapsular fractures, 286 extracapsular fractures, and 12 subtrochanteric fractures) were treated surgically between April 2005 to October 2007. The level of experience among trainees was quantified as the number of PFF they had fixed or replaced as the first surgeon, from the start of their training at Senior House Officer level to the beginning of the study period.

Logistic regression model was used to investigate the relationship between mortality and re-operation at six months and case mix variables (age, ASA grade, fracture types, pre-fracture residence, and mobility and activity level), and management variables (days to operation, the grade of the surgeon and supervision level). Mann-Whitney test was used to compare the level of experience among trainees in the group of patients who died or required re-operation at six months.

Results: At six months, the mortality rate was 24.2% (184) and the re-operation rate was 3.8% (29).

The logistic regression model used to predict six months mortality was highly significant (X2=166.6 [24df], p< 0.0001). It showed that age, ASA grade and pre-fracture activity level were strongly associated with mortality at six months. Patients operated on by a trainee without the consultant being scrubbed were 1.8 times (p< 0.05) more likely to die at 6 months. (Odds ratio of 1.8 with 95% confidence interval of 1.15 to 2.75). Re-operation at six months could not be predicted by these factors.

Regarding patients operated on by trainees, there was no significant difference in the level of experience among trainees who operated on patients who died or who required re-operation at six months compared to those who did not.

Aim: To compare the acute haemoglobin level drop following hip fracture fixation with IMHS and CHS at James Cook University Hospital and assess whether the surgeon’s seniority has any effect on the amount of blood loss in these two procedures.

Methods: Trauma data base was searched for all IMHS procedures performed from January 2002 till March 2007 both included and CHS procedures performed from January 2007 till March 2008 both included.

There were 159 CHS procedures and 146 IMHS procedures. 137 CHS and 123 IMHS procedures fulfilled the blood testing and transfusion criteria.

Haemoglobin levels were used as an indication for blood loss attributable to surgery. The difference between the last level of haemoglobin checked preoperatively and the first post operative level performed between 12–48 hours postoperatively is calculated. Cases where blood transfusion was carried out preoperatively without further preoperative haemoglobin check were excluded, so were cases receiving intra or post operative blood transfusion prior to the defined postoperative haemoglobin check was carried out.

Results: SPSS 13.0 statistical package was used to analyse the results. Levene’s test proved equality of variances of blood loss within the two groups of patients undergoing one of the two procedures, P=0.5. Hence, Independent Samples T test was applicable and showed that patients undergoing an IMHS procedure dropped their haemoglobin levels by 2.96 g/dl. While, those undergoing a CHS procedure dropped their haemoglobin levels by 2.32 g/dl. The 0.64 g/dl difference in haemoglobin drop was statistically significant at 5% significance level with 95% CI (0.27 to 1.01), P=0.001.

The surgeons’ grades were classified into three groups as: Consultants, Registrars and Senior House Officers. Levene’s test again proved the variances of haemoglobin drop within each group to be homogeneous. Hence a One-Way ANOVA test was carried out showing that the differences in haemoglobin drop were not statistically significant when comparing the three groups of surgeons to each other. This was true for both IMHS and CHS procedures.

Conclusion: Patients undergoing a CHS procedure drop their haemoglobin levels by 0.64 g/dl less than those undergoing an IMHS procedure. The surgeon’s seniority does not make difference to the amount of haemoglobin level drop following either of the two procedures.

We recommend the use of CHS for stable fractures and reserve the IMHS for the unstable ones due to the increased blood loss with IMHS procedures.

Introduction: Classification systems are useful in research and clinical practise as it provides a common mode of communication and evaluation. Tibial pilon injuries are a complex group of fractures, whose classification and radiological assessment in clinical practise remains undetermined.

Methods: 50 CT scans and radiographs of tibial pilon fractures were evaluated independently by 6 orthopaedic surgeons, comprising 3 consultants, 2 registrars and 1 research fellow. Fractures were classified according to ruedi allgower, AO, Topliss et al. Each surgeon was given a period of 48 hours to review copy of the original article as well as written and diagrammatic representations. Assessment was done on two occasions, 4 weeks apart. The kappa coefficient of agreement was calculated with SPSS to determine interobserver reliability and intraobserver reproducibility of the classification systems. The evaluator was blinded as to treatment and functional outcome. Each evaluator was also asked to decide upon the fracture management based on the classification types and was compared with the actual management.

Result: The interobserver agreement for ruedi allgower, Ao and Topliss et al., was fair, moderate and poor respectively. The intraobserver agreement for ruedi allgower, AO and Topliss et al., classifications was moderate at best. There was poor agreement amongst observers regarding definite management plan based on these classification systems.

Discussion: The interobserver agreement was directly proportional to the familiarity and inversely proportional to the specificity of the classification system. The intraobserver agreement improved with experience. CT scan helped in delineating the fracture segments accurately but did not significantly affect inter or intraob-server agreement.

Conclusion: Existing classification systems help in understanding the pathoanatomy of osseous part of tibial pilon fracture complex. However, Soft tissue injury forms an integral part of this complex. Without inclusion of soft tissue injury, these classification systems have limited role in definitive management.

Introduction: Previous studies have demonstrated the value of the tip-apex distance (TAD) and the location of the screw in the femoral head in predicting cut-out. Similarly surgeons’ volume has been shown to affect mortality and morbidity in various surgical specialties, including in trauma and orthopaedics.

Aim: To determine whether re-operation due to cut out at six month can be predicted using TAD, location of the screw and fracture type; and whether the experience of the surgeon is important.

Methods: Logistic regression was used to analyse data collected retrospectively from 241 patients with extracapsular fractures (Jensen’s modification of Evans’ classification: Class I – 90, Class II – 93 and Class III – 58), treated with a dynamic hip screw, classic hip screw or intramedullary hip screw from April 2005 to October 2007.

Results: There were 7 cut outs (2.5%) requiring re-operation within 6 months – 1 in the consultant group and 6 in the trainee group,. The model used was statistically significant (X2=23.6 [13df], p< 0.05). The tip-apex distance was a strong predictor (p< 0.05) of cut-out requiring re-operation at six months. The odds of the patient requiring re-operation due to cut out increases by a factor of 1.2 for each millimetre increase in the TAD. Location of the hip screw and fracture type were however not significant predictors. The first surgeon was a consultant in 54 cases and trainee in 187 cases. There was no statistically significant difference in re-operation rate due to cut out between patients operated on by consultants compared to trainees.

Conclusion: The TAD is a strong predictor of cut out requiring re-operation at 6 months. No difference was found in our series in re-operation rate due to cut out among cases performed by consultants compared to trainees.

Idiopathic anterior knee pain (AKP) is common in adolescents and young adults. Most believe that the origin of the problem lies in the patello-femoral joint. Hamstring tightness has also been attributed as an important cause.

The aim of our study was to compare biometric parameters in patients with idiopathic AKP and controls. We also wanted to assess whether there was a difference in the relative electromyographic (EMG) onset times of the medial and lateral hamstrings.

We prospectively recruited patients with idiopathic anterior knee pain in the age group 11 to 25. Patients, but not the control population, had AP, lateral and skyline radiographs taken to rule out other pathology.

We had 34 patients (60 knees) with a minimum one year follow up. There was no difference in the symptoms of patients who attended physiotherapy as compared to those who did not. Patients with knee pain had significantly more hip external rotation (63 deg) as compared to the control (47 deg) group (p=0.001). Patients also had significantly more hamstring tightness (p=0.04).

Surface EMG was recorded (17 patients and controls each) from the medial and lateral hamstrings during 3 repetitions of a maximal voluntary isometric contraction exercise with the knee at 45° of flexion. The lateral hamstrings contracted 48.7 m.sec earlier than the medial hamstrings in patients as compared to controls.

AKP is a multifactorial and self-limiting disorder. Earlier contraction of the lateral hamstrings may cause tibial external rotation and contribute to the symptoms. Our data suggests that physiotherapy did not significantly alter the course of the condition. We believe that increased hip external rotation may contribute to the symptoms by increasing medial facet stress.

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.

Introduction: Several institutes in continental Europe and the US now prescribe low molecular weight heparin for patients with ankle fractures being treated in a below knee plaster cast. Jorgensen et al reported an incidence of deep venous thrombosis (DVT) of up to 20% in patients treated in a cast. However, their study included patients with variable diagnoses, ranging from tendon ruptures to fractures. The aim of our study was to assess the incidence of DVT in patients with ankle fractures that have been treated conservatively in a below knee cast.

Method: We performed an ultrasound scan on patients with conservatively ankle fractures at the time of removal of the cast. The same ultrasound technician performed all the scans. The local regional ethics committee had approved this study.

Results: So far we have performed an ultrasound scan on 98 patients with ankle fractures. We are likely to complete the study in November 2006 (120 patients). We have encountered only 2 below knee DVTs (2.04 %). None of them involved the popliteal vein. Both patients were completely asymptomatic and were full weight bearing in the cast. A repeat scan showed no evidence of progression. None of the patients had an above knee DVT or a pulmonary embolism.

Discussion: The risk of deep venous thrombosis is said to be higher in patients with a plaster cast because of the decreased ability of the calf muscles to pump the venous blood back to the heart. Though some studies have indicated an incidence of up to 20%, the incidence in our population was only about 2%Thus, DVT is a rare event in patients with ankle fractures. Though it is a serious event, its rarity does not justify a blanket prophylaxis regimen for all patients with ankle fractures.

Introduction: Poor proprioception and imbalance between quadriceps and hamstrings have been suggested as causes for anterior knee pain. The aim of our study was to compare the proprioception of patients with anterior knee pain to a normal population and to compare the activity of quadriceps and hamstrings using electromyography (EMG) in the 2 groups.

Methods: Patients and controls between the ages 11–25 yrs were recruited into the study. The proprioception (stability index) of the patients and controls was tested using the Biodex stability system. This computerised system tests the ability of a person to balance his/her own body on a platform that moves in various directions. Surface EMG was recorded from the quadriceps and hamstrings during this test. EMG was also recorded as the patients and controls stepped onto a 20cm step. EMG activity was normalised to levels elicited during maximal isometric contractions.

Results: 18 patients and 27 controls were recruited.

We found no significant difference between the groups in the EMG intensity of vastus lateralis relative to biceps femoris, or vastus medialis relative to vastus lateralis, during the balance test or during the step up task (Mann Whitney U test all p> 0.05). We did not find any difference in the proprioceptive abilities of the two groups

Conclusion: We found no significant difference between the groups in the intensity of muscle contraction of the hamstrings relative to the quadriceps, i.e. no evidence for an imbalance in the patients. However the temporal relation between the two needs further investigation.

The aim of this study was to determine whether there is a difference in the functional outcome between fixed and mobile bearings in total knee arthroplasty.

120 patients were randomized (computer generated) to receive either a fixed or mobile bearing P.F.C. Sigma total knee replacement. 96 patients were needed to detect a 20° difference in range of motion (ROM) with a significance level of 0.05 and a test power of 0.97. Oxford knee score (OKS) and ROM were assessed independently before and one year after surgery.

Mean ROM and Oxford knee score before and at one year after surgery for both groups are shown as preliminary results for 70 patients (follow-up expected to be completed by March 2006):

There is no statistically significant difference in the mean ROM at one year and in change in ROM between the two groups (p=0.53 and p=0.21 respectively). The findings were similar for Oxford Knee Score at one year and change in Oxford Knee Score (p=0.45 and p=0.82). There was no early aseptic loosening in either group.

The one year results suggest that there is no significant difference in functional outcome measured as ROM and Oxford Knee Score between the two types of bearing. Further follow-up will be carried out to detect any differences in the long term outcome.

The purpose of this study was to determine contact patterns in cementless acetabular cups using a novel computed tomography (CT) scan analysis technique. Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive one of three cup designs. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone pros-thesis contact.

The purpose of this study was to determine contact patterns in cementless acetabular cups using computed tomography (CT) scan analysis.

Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive a hemispherical cup, a dual geometry cup, or a spiked cup. After radiographic templating, an experienced orthopaedic team prepared the specimens and implanted the acetabular cups. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. Contact was defined as a bone-prosthesis distance of 0.5 mm or less.

The mean amount of cup contact was 40.4% (SD=8.2%) in the hemisphere group, 24.7% (SD=2.3%) in the dual geometry group, and 29.7% (SD=9.5%) in the spiked group. Colour mapping of the bone-prosthesis gap was used to identify contact/non-contact regions along the acetabular contour for all cup designs.

Preliminary work with this CT analysis technique demonstrates differences in the amount and distribution of contact in the acetabular cup designs. Future work will involve development of an imaging phantom to clarify error, use of the technique with different cup designs and reaming techniques, and comparison of this technique with conventional CT scan techniques.

This study outlines a novel CT analysis technique for quantitatively determining bone-prosthesis contact for cementless acetabular cups.

The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone prosthesis contact.

Funding: Smith and Nephew

Aim: To investigate in vitro the mechanical stability of a locking compression plate (LCP) construct in a simulated diaphyseal fracture of the humerus at increasing distances between the plate and bone.

Materials & Method: A series of biomechanical in vitro experiments were performed using Composite Humerus Sawbone as the bone model. Osteotomy created in the mid-diaphyseal region. A 10mm osteotomy gap was bridged with a 7-hole 4.5 stainless steel plate with one of four methods: a control group consisted of a Dynamic Compression Plate applied flush to the bone and three study groups which comprised of a LCP applied flush to the bone, at 2mm and at 5mm from the bone. Standard AO technique used with locking head screws used for LCP fixation. Static and dynamic loading tests performed in a jig with the bone model fixed both proximally and distally. Samples were subjected to cyclical compression, compression load to failure, cyclical torque and torque to failure. Plastic deformation and failure was assessed. Scanning electron microscopy of the plate and screw surface allowed detailed inspection of micro-fracture in areas of fatigue.

Results: Consistent results were achieved in LCP constructs in which the plate was applied at or less than 2mm from the bone. When applied 5mm from the bone the LCP demonstrated significantly increased plastic deformation during cyclical compression and required lower loads to induce construct failure.

Conclusion: In our laboratory model a significant decrease in axial stiffness and torsional rigidity becomes evident at a distance of 5mm between plate and bone.

Aim: This study compares the MRI scan with clinical diagnosis, and looks at the reliability of both these against the gold standard of arthroscopic diagnosis, in disorders of the knee.

Materials and methods: The patients were from the knee specialist unit of a tertiary referral centre seen and operated by the senior author , over a two year period. This is a retrospective study. The total number of patients in this study was 58(n=58) , with ages ranging from 18–63 years. The results were obtained using statistical formulae, which calculated the sensitivity , Specificity , accuracy and the positive and negative predictive values of the MRI scan and that of clinical diagnosis .

Results: The MRI scan was found to be significantly sensitive in diagnosis of medial meniscal lesions, 96% (95% Confidence interval 89–100), it was also found to be significantly specific in diagnosis of lateral meniscal, 90% ( 95% CI, 81–98) and ACL lesions 94% (95% CI,87–100). The MRI scan had poor sensitivity and specificity for articular cartilage lesions.

The sensitivity of clinical diagnosis for medial and lateral meniscus and ACL lesions was found to be less than 90%. Clinical impression was found to be significantly specific for lesions of ACL and the articular cartilage.

The negative predictive value of the MRI scan was found to be significantly high (> 95%), for lesions of the medial and lateral meniscus and the ACL.

Conclusion: The MRI had a poor diagnostic value in diagnosing and quantifying articular cartilage (chondral) lesions. Clinical diagnosis had a lower sensitivity as compared to MRI in diagnosis of medial meniscal lesions but was more specific in diagnosing cruciate and articular cartilage pathology. The reliability of a high negative predictive value for the MRI scan in ruling out medial meniscus, lateral meniscus and ACL lesion was demonstrated. Therefore, a ‘normal’ scan can be used to exclude lesions. thus sparing patients from expensive and unnecessary surgery and also freeing up valuable theatre time.

Purpose of the study: To determine usefulness of skyline x-ray in diagnosis of patellofemoral osteoarthritis.

Materials and Methods: 50 patients scheduled to undergo knee surgery, had standard antero-posterior, lateral and skyline x-rays of their affected knee. At operation, their patellofemoral joints were graded into two groups according to presence or absence of osteoarthritis. Their lateral and skyline x-rays were also graded into the same two groups, according to presence or absence of patellofemoral osteoarthritis. The two x-ray views were then compared individually against operative findings.

Results: The skyline view had sensitivity of 79% (95% confidence intervals (C.I.) 66% to 93%) and specificity of 80% (95% C.I. 62% to 98%). The lateral view had sensitivity of 82% (95% C.I. 69% to 95%) and specificity of 65% (95% C.I. 44% to 86%).

Conclusion: There was no statistically significant difference between the two x-ray views in terms of sensitivity and specificity in the diagnosis of patellofemoral osteoarthritis of the knee joint. Hence, we cannot recommend the skyline view as a routine radiological investigation in all cases of suspected patellofemoral osteoarthritis.

Introduction: (OCD) is characterized by bone necrosis and softening of the overlying cartilage, which may separate and displace. It is thought to be secondary to trauma, ischaemia or abnormal epiphyseal ossification. Management remains controversial during the early stages of the disease. Surgery for advanced chondral lesions with loose bodies however remains a challenge. Options that include periosteal graft and autologous chondrocyte transplantation have been used with variable degrees of success. This study investigates the efficacy of these techniques and the use of mesenchymal stem cells to treat advanced chondral lesions found in OCD in animal models.

Materials and Methods: A full thickness articular cartilage defect (6mm long, 3mm wide and 1mm deep) was created in the weight-bearing surface of medial femoral condyle in 22-week old NZW rabbits. A total of 90 knees were randomly divided into 3 groups as follows: 1) Transfer of cultured chondrocytes 2) Transfer of cultured periosteum-derived MSCs and 3) Repair by periosteal graft with their contralateral knees as control. The rabbits were allowed to move freely in their cages. The rabbits were sacrificed at 2, 6, 12, 24 and 36 weeks post-operatively. The healing of the defects was assessed by gross examination and histological grading and subjected biomechanical testing.

Results: Gross and histological examination at 36 weeks post operation (Wakitani et al grading), the mean score for Group 1 is 2.5, Group 2 is 2.3 and Group 3 is 4.5 with control group of 8.9 in terms of cell morphology, matrix staining, surface regularity, thickness of repaired cartilage and integration of cartilage to adjacent host. Biomechanically by indentation test, Group1 had value of 0.22 MPa, Group 2 0.20 MPa, Group 3 0.16 MPa and Control group of 0.12 MPa.

Conclusion: The findings suggested that cultured chondrocytes and mesenchymal stem cells had comparable enhancing effect of the repair of chondral defect in advanced OCD

Clinical investigations and tests need to be validated by studying their inter-observer and intra-observer errors, but there has been no documentation of such verification in diagnostic knee arthroscopy. We performed a prospective study to find out to what extent the findings in knee arthroscopy differ between two different surgeons.

Two senior specialist registrars (M.S. and A.J.) who took part in this study worked with the senior author (ACW) for a period of eight and seven months respectively. A total of 78 knee arthroscopies admitted from routine waiting list were studied. The specialist registrar first performed arthroscopy when the supervising consultant stayed away from the operating room. His findings were recorded on a proforma by an independent third person before the consultant returned to the operating room and repeated the EUA and arthroscopy without prior knowledge of the trainee findings. Findings from the consultant arthroscopy were then recorded separately on the same proforma.

The following findings were recorded:

Examination under anaesthesia

The inter-observer variations in diagnostic knee arthroscopy were found to be high. Given the seniority and experience of the two trainee senior registrars involved in the study, and allowing for the Hawthorne effect, the results of the study cast doubt on this procedure being performed un-supervised. It also questions the validity of any therapeutic intervention based on the findings of un-supervised arthroscopies.

Video-assisted thoracoscopic surgery (VATS) has been in use since the 1980s for surgery of the spine. Initially it was used for anterior release of the thoracic spine in order to facilitate posterior instrumentation. With increasing experience, it has been applied to perform definitive correction and instrumentation. Video-assisted thoracoscopic spine surgery allows the surgeon to perform anterior thoracic spine operations with fewer levels of instrumentation, reducing the crankshaft effect and removing the morbidity associated with thoracotomy. From 1996 to November 2000, our center performed 19 such operations. 18 of them were completed successfully endoscopically and one was converted to an open procedure. An initial group of 10 patients underwent thoracoscopic anterior release and fusion followed by same day posterior instrumentation and fusion. Subsequently, 6 patients underwent anterior discectomies, fusion with instrumentation via thoracoscopic approach.

For the initial 10 patients, the average operative time was 190 minutes. The average post-operative correction was 62 % and blood loss was 350 mLs. For the 6 patients who underwent anterior discectomies, fusion and instrumentation via the thoracoscopic approach, the average operative time was 360 minutes; average post-operative correction was 70% and blood loss was 400 mLs.

Complications encountered were minor and included one case ofcontralateral pneumothorax, one patient complained of transient limb numbness which resolved within 6 weeks. It is our conclusion that thoracoscopic anterior spinal surgery, though with learning curve, a safe and effective procedure.

Objective: To determine the efficacy and safety of pamidronate combined with intramedullary rodding in improving bone mineralisation and reducing fracture incidence in children with osteogenesis imperfecta (O.I.).

Methods: A prospective pilot, open study was performed in which intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to 12 children with O.I., over 18 – 28 months. The children were serially monitored for symptoms, anthropometric measurements, fracture incidence, biochemical assessments of calcium metabolism, bone mineral density (BMD), serum alkaline phosphatase (ALP), urinary N-telopeptides, and spine X-rays. Intra-medullary rodding of fractures were performed with when there was definite angulation of bones.

Results: The number of fractures decreased from 4 to 0.85 fractures/year during pamidronate therapy (p< 0.05). After 18 months of treatment, there was significant improvement in Areal BMD z scores of the lumbar spine from −2.38 to −1.76 (p < 0.05) and in the Volumetric BMD, which increased from 0.06 to 0.09 g/cm3 (p < 0.05). At 18 months, urine N-telopeptide levels (bone resorption marker), decreased from 439.7 to 222.3 BCE/Cr (p < 0.05), and serum ALP (bone formation marker) from 225.0 to 143.5 U/L (p < 0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption, and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected, and there were no significant adverse effects.

Conclusion: 18 months cyclical pamidronate is effective in improving bone mineralisation, and reducing fracture incidence in O.I. Pamidronate therapy, which was safe, and when combined with intra-medullary rodding, can potentially improve the quality of life by improving mobility and preventing post-fracture deformities, thus offering new hope for children afflicted with OI.

Introduction: Surgery in patients with neuromuscular scoliosis is aimed at improving truncal balance, facilitating sitting, prevention of progression of the curve and preservation of respiratory function.

Patients and Methods: This was a retrospective study of surgical results in a group of 24 patients with minimum follow up of 2 years an average post-operative follow up of 5 years (2–9 years) with neuromuscular scoliosis due to varying aetiologies. The aetiologies included SMA (7), CP (6), Duchenne (5), Congenital Myopathies (3), Spina Bifida (2) and Paraspinal Neuroblastoma (1).

Results: The average age at surgery was 10.6 years, the average duration was 4hrs 25mins with an average blood loss pf 1.1 liters. An average ICU stay was 1–2 days and stay in hospital is 11 days. The curves ranged from 25–103° (average 75.6°) pre-operative and we were able to obtain a correction of 56%. In all but 2 of our patients we were successful in preventing deterioration of respiratory function and all our patients could at least sit without support post-operatively. Our complications included only one deep infection (necessitating implant removal), 1 rod breakage and 2 patients with UTI. There were no significant respiratory complications in post-operation.

Conclusion: Spinal surgery in patients with neuromuscular scoliosis is safe and prevents deterioration of respiratory and improve truncal balance and hence quality of life.