Excessive implant migration and micromotion have been related to eventual implant loosening. The aim of this project is to develop a computational tool that will be able to predict the mechanical performance of a cementless implant in the presence of uncertainty, for example through variations in implant alignment or bone quality. To achieve this aim, a computational model has to be developed and implemented. However, to gain confidence in the model, it should be verified experimentally. To this end, the present work investigated the behavior of a cementless implant experimentally, and compared the results with a computational model of the same test setup.

A synthetic bone (item 3406, Sawbones Europe AB, Sweden) was surgically implanted with a Furlong cementless stem (JRI, Sheffield, UK) in a neutral position and subjected to a compression fatigue test of −200 N to −1.6 kN at a frequency of 0.5 Hz for 50000 cycles. Measurements of the micromotion and migration were carried out using two linear variable differential transducers and the strain on the cortex of the femur was measured by a digital image correlation system (Limess Messtechnik & Software Gmbh).

A three-dimensional model was generated from computed tomography scans of the implanted Sawbone and converted to a finite element (FE) model using Simple-ware software (Simpleware Ltd, Exeter, UK). Face-to-face elements were used to generate a contact pair between the Sawbone and the implant. A contact stiffness of 6000 N/m and a friction coefficient of 0.3 were assigned. The analysis simulated a load of −1.6 kN applied to the head of the implant shortly post implantation. The motions and strains recorded in the experiment were compared with the predictions from the computational model. The micromotion (the vertical movement of the implant during a single load cycle), was measured at the proximal shoulder, at the distal tip of the implant and at the bone-implant interface. The maximum value calculated proximally using FE was 61.3 μm compared to the experimental value of 59.6 μm. At the distal end, the maximum micromotion from FE was 168.9 μm compared to 170 μm experimentally. As a point of reference, some authors have suggested that in vivo, fibrous tissue formation may take place at the bone-implant interface when the micromotion is above 150 μm. The maximum micromotion found computationally at this interface was 99 μm which is below the threshold value defined. The longitudinal strain over the surface of the bone was variable and reached values of up to 0.15% computationally and 0.4% experimentally; this may be related to the coordinate systems used. However, it was noted that digital image correlation identified qualitatively similar strain patterns, and has great potential for measuring low level surface strains on bone.

In conclusion, the good correlation between the computational modelling and experimental tests provides confidence in the model for further investigations using probabilistic analyses where more complex configurations (for example change in implant alignment) can be analyzed.

Introduction: One of the main factors in the success of impaction bone grafting (IBG) in revision hip surgery is its ability to resist shear and to form a stable construct. Bone marrow contains multipotent skeletal stem cells and we propose that in combination with allograft will produce a living composite with biological and mechanical potential. In this study we looked at whether coating of the allograft with type 1 collagen followed by seeding with human bone marrow stromal cells (hBMSC) would enhance the grafts mechanical and biological properties.

Methods: A control group of plain allograft and three experimental groups where used to determine the effects that collagen and hBMSC have on IBG. The samples where impacted in standardised fashion previously validated to replicate femoral IBG, and cultured in vitro for 2 weeks. The samples then underwent mechanical shear testing and biochemical analysis for DNA content and Osteogenic activity.

Results: Collagen coating of the allograft prior to seeding with hBMSC significantly enhanced the mechanical properties of the construct compared to the ‘gold standard’ of plain allograft with a 22% increase in shear strength (p=0.002). The collagen coated group also showed increased osteogenic differentiation of the stromal cells (Alkaline Phospatase specific activity: 124 +/− 18.6 vs 54.6 +/− 9.6 nM pNPP/Hr/ngDNA p= < 0.01).

Discussion: This study has shown a role in the improvement of the biomechanical properties of IBG by coating with collagen and seeding with hBMSC. Collagen coating of IBG is a simple process and translation of the technique into the theatre setting feasible. The improvement in shear strength and cohesion could lead to earlier weight bearing for the patients and allow quicker recovery. The therapeutic implications of such composites auger well for orthopaedic applications. We are currently strengthening the above findings with an in vivo study.

Purpose: Females are at greater risk for anterior cruciate ligament (ACL) injury than males. Soccer may be a significant risk factor for ACL injury in adolescent females. ACL injury has significant consequences, including early onset of osteoarthritis. The purpose of the study was to determine

the number of ACL reconstruction surgeries performed on females between the ages of 13–18 inclusive in the Capital Health (CH) region from December 2000 to November 2005, and

Secondly, we describe factors relating to the mechanism of injury.

Method: Utilizing regional administrative data, we performed a standardized chart review and telephone interviews with female adolescents who underwent ACL reconstruction in the aforementioned time period. Information gathered included:

Age at reconstruction procedure.

The Alberta Soccer Association provided the number of registrants in indoor and outdoor seasons over the same time period.

Results: 2,824 ACL reconstruction operations were performed between December 2000 and November 2005. Reconstructions in females took place at an earlier age than in males. There were 266 ACL reconstructions in 256 adolescent females, of which 253 charts were available for review. One hundred and eleven (44%) knees were injured during soccer play. Seven patients with eight ACL reconstructions who injured their ACL playing soccer could not be located. ACL injuries occurred during indoor soccer in 52 (51%) cases despite higher registration in outdoor soccer during the same time-frame. 77 (74%) subjects played competitively and 81 (79%) subjects played two or more times/week.

Conclusion: Approximately 10% of ACL reconstructions were performed on adolescent females. Nearly 50% of ACL injuries occurred during soccer play, with a similar number seen in indoor versus outdoor play. Study limitations include the use of administrative data to assess the number of ACL reconstructions rather than ACL injuries. An awareness of the propensity of knee injuries in female soccer players is important. With the increased participation of young females in soccer and the serious lifelong implications of ACL rupture, prevention and training should be improved to lower the incidence of injury.

We aimed to evaluate the effects of implementing blood conservation strategies on transfusion requirements in adult patients undergoing scoliosis correction surgery. We retrospectively studied 50 consecutive adult patients who underwent scoliosis correction surgery (anterior, posterior or combined) between 2003 and 2007. All patients had a standard transfusion protocol. Age, BMI, pre and post operative haemoglobin, levels fused, duration of surgery, hospital stay, anti-fibrinolytics used and blood transfused was noted.

50 patients with mean age 24.6 years and mean BMI 21.9 kg/m2 were studied. 14 patients had anterior surgery, 19 patients had posterior surgery and 17 had combined anterior and posterior procedures. Mean number of levels fused was 9.5 (6–15) and mean duration of surgery was 284.6 minutes (135–550 minutes). Antifibrinolytics were used in 31 patients (62%), Aprotinin in 21(42%) and Tranexamic acid in 10 (20%). Mean blood loss in patients who received anti fibrinolytics was 530mls while mean blood loss in the other patients was 672mls. (p< 0.05). Blood transfusion was not required in any of the patients undergoing anterior correction only while 7 patients (41%) undergoing anterior and posterior correction and 3 patients (15.8%) undergoing posterior correction only required blood transfusion. Mean volume of cell saved blood re-transfused was 693.8 mls and mean hospital stay was 9.2 days. Mean pre-op haemoglobin was 13.2 g/dl (10.4–17.4) and mean post-op haemoglobin was 10.7 g/dl (7.7–15). 4 patients (8%) required intra and post-operative blood transfusion while 6 patients (12%) required blood transfusion postoperatively.

In conclusion, the use of anti-fibrinolytics like Aprotinin and Tranexamic acid reduces blood loss in scoliosis surgery. In the current scenario, with Aprotinin no longer available for use, our study would recommend the use of Tranexamic acid alongwith other blood conservation measures. In our unit we do not have blood cross matched for anterior surgery alone.

Introduction: Revision hip surgery is predicted to rise significantly over the coming decades. There is therefore likely to be an increasing need to overcome the large bone loss and cavitatory defects encountered in failed primary hip replacements. Impaction bone grafting (IBG) is a recognised technique for replacing lost bone stock. Achieving optimal graft impaction is a difficult surgical skill with a significant learning curve, balancing the need to achieve sufficient compaction to provide primary stability versus the need to keep impaction forces to a minimum to prevent iatrogenic fracture. In this study we have developed a revision acetabular model to test the hypothesis that the use of vibration and drainage with a new custom made perforated tamp could reduce the peak stresses imparted to the acetabulum during the impaction process and also improve the reliability and reproducibility of the impaction technique

Methods: Composite Sawbone hemi Pelvis models were used, with identical contained cavitatory defects created (Paprosky Type 2a). A strain gauge was attached to the medial wall of each hemi pelvis. A custom set of IBG tamps were made, and coupled a pneumatic hammer used to generate the vibrations. A standard impaction technique was used for the control group and the new vibration impaction for the experimental group. The cavity was progressively filled with morsellised allograft in 6 set steps for both groups with strain gauge readings taken during all impaction to monitor peak stresses. A standard Exeter Contemporary cup was then cemented into the graft bed for both groups. The models were mechanically loaded according to the protocol developed by Westphal et al at the angle of the joint reaction force during heel strike for a total of 50 000 cycles. 3D assessment of any micro motion post mechanical testing and degree of graft compaction was done with high resolution micro CT.

Results: Vibration impaction lead to a significant reduction in the peak stresses during the impaction process throughout the 6 steps (e.g. Step 1: 34.6 vs 110.8 MPa p=0.03). There was also far less variability in the peak stresses in the vibration group compared to standard impaction both in sequential impactions by the same surgeon and between different surgeons. One medial wall fracture occurred in the control group only. There was no difference in the degree of graft compaction or in the subsidence of the implant post cyclical loading.

Conclusion: Impaction bone grafting can be a difficult surgical skill with a significant learning curve. We believe that this new technique of applying vibration coupled with drainage to the IBG process in the acetabulum can reduce the risk of intraoperative fracture whilst achieving good graft compaction and implant stability. This technique therefore has the potential to widen the ‘safety margins’ of IBG and reduce the learning curve allowing more widespread adoption of the technique for replacing lost bone stock.

Introduction: Impaction bone grafting (IBG) using fresh frozen morsellised allograft is considered by many as the method of choice for replacing lost bone stock encountered during revision hip surgery. Bone marrow contains multipotent skeletal stem cells which have the potential to differentiate down a number of different cell lineages including osteoblasts, chondrocytes and adipocytes. In IBG it is desirable for as many as possible to go on to form bone rather than fibrous tissue to form a solid osseous construct. Whilst it is possible to push cells down the osteogenic lineage in vitro, some of these methods (e.g. the addition of Dexamethasone) are not translatable to clinical practice due to undesirable side effects. In this study we test the hypothesis that by coating the allograft with type 1 Collagen prior to seeding with human bone marrow stromal cells (hBMSC), the cellular adhesion and proliferation down an osteogenic lineage can be increased, leading to improved mechanical and biological properties of the IBG composite.

Methods: A control group of plain allograft and three experimental groups where used to determine the effects that collagen and hBMSC have on IBG (both individually and in combination). The samples where impacted in standardised fashion previously validated to replicate Femoral IBG, and cultured in vitro for 2 weeks. The samples then underwent mechanical shear testing giving a family of stress strain curves for each group, from which a Mohr coulomb failure curve can be plotted. Using the Mohr Coulomb failure equation τ = σ tanΦ + c, the shear strength (τ), Internal friction angle (tanΦ) and inter particulate cohesion (c) can then be calculated. Biochemical analysis was also performed for DNA content and Osteogenic activity.

Results: Mechanical shear testing demonstrated a significant improvement (p=0.002) in the grafts ability to resist shear with the coating of Collagen and seeding with hBMSC (245 vs 299 kPa) as well as improved cohesion between the bone graft particles (46 vs 144 kPa). Regression analysis of the shear strength showed a linear increase with compressive stress (R2 > 0.98) for all groups, indicating that the grafts satisfied the Mohr Coulomb failure law. In the two groups seeded with cells, the collagen coated group also showed increased osteogenic cell activity compared to the plain allograft.

Conclusion: This study has shown a role in the improvement of the mechanical and biological properties of IBG coated with type 1 Collagen and seeded with hBMSC. Collagen coating of IBG is a facile process and translation of the technique into the theatre setting feasible. The improvement in shear strength and cohesion could lead to earlier weight bearing for the patients and allow quicker recovery. The therapeutic implications of such composites auger well for orthopaedic applications. We are currently strengthening the above findings with an in vivo study.

Background: The simultaneous occurrence of spina bifida occulta (SBO) and spondylolysis has been noted previously. The occurrence of SBO and spondylolysis are approximately 17% and 5% respectively.

Aims: The aim of this study was to determine the incidence of SBO when a symptomatic spondylolysis has been proven.

Method: Analysis of four years of lumbar spine CT scans was performed. Patients with spondylolysis or spondylolisthesis caused by a pars defect were identified. These patients’ CT images were then reviewed to establish the patients who also had SBO.

Results: In this unit 650 CT scans of lumbar spines were performed in the last five years. Of these scans 100 (15%) were found to have a pars defect. The average age was 34.6. On CT 30 (30%) patients were shown to have SBO. Of the total 23 were under 18 years old and 13 (56%) of these patients had SBO associated with the spondylolysis. In the over 18 year olds 21 (27%) patients had SBO associated with spondylolysis.

On review of the 550 other scans the average age was 51.9 years old. The incidence of SBO within this group is 10%. Only 6% of these patients were under 18. Out of these 33 patients 30.3% (10 patients) had SBO. Over 18 the incidence of SBO was only 8.5%.

Conclusions: Our results indicate that the occurrence of SBO within the group with a spondylolysis is much higher than in the group where no spondylolysis is present. There is higher incidence of SBO in the younger patients with spondylolysis. 56% of paediatric patients with symptomatic spondylolysis will have SBO. Clinicians should be aware of this fact preoperatively to decide on the technique of repair of the symptomatic lysis.

Introduction: Impaction bone grafting (IBG) for revision hip surgery can be a difficult surgical skill with a fine line between construct failure from insufficient compaction and intraoperative fracture from high impaction forces. Following on from our experience in the femur, in this study we used an acetabular model to test the hypothesis that the use of vibration for IBG could reduce the peak stresses thus reducing the intraoperative fracture risk and also improve the reliability and reproducibility of the impaction technique.

Methods: Revision hemi pelvis models were made (Pra-prosky Type 2a). A standard impaction technique was used for the control group, and the impactor tamps were coupled with a pneumatic hammer for the vibration group. The cavity was filled in 6 set steps with strain gauge readings taken throughout. The pelvis construct was then mechanically loaded. Graft compaction and micro motion post mechanical testing was assessed with micro CT.

Results: Vibration impaction led to a significant reduction (p=0.03) in the peak stresses during the impaction process. There was also significantly less variability in peak stresses for the vibration group compared to standard, both in sequential impactions by the same surgeon and between different surgeons. One medial wall fracture occurred in the control group only, similar to fractures encountered in the clinical situation. There was no significant difference in the degree of graft compaction or in the subsidence of the cup.

Discussion: We believe that this new technique of applying vibration to the IBG process can reduce the risk of intraoperative fracture whilst achieving good graft compaction and implant stability. This technique therefore has the potential to widen the ‘safety margins’ of IBG and reduce the learning curve allowing more widespread adoption of the technique for replacing lost bone stock.

Background: Satisfaction following anterior and/or posterior spinal fusion varies greatly between individuals. The aim of this study was to assess patient satisfaction with the post-operative scars following surgical correction of scoliosis.

Methods: Prospective study; 31 patients (range 10–37 years), minimum of 2 months post-operation, interviewed in clinic or over the telephone using a questionnaire.

Results: Overall, 18 (58%) patients were disappointed with their scar; it was not what they expected, Patients with anterior scars or both anterior and posterior scars were the most disappointed groups.

39% of patients felt they were inadequately informed or not informed of the nature of scar. However, over 50% of those who had a specialist spinal nurse (SSN) consultation reported the scar to be as they expected. Scar length was the main source of disappointment. 55% reported their scars as being raised (keloid), particularly at the ends. Scar colour and shape was an issue for 23%, whilst 39% experienced prolonged healing. 19 patients had a pre-op consultation with the SSN, 11 did not get this opportunity, 1 declined.

Conclusion: Clearly there’s a need for improved education and understanding with regard to the nature of the scoliosis surgical scar(s). Input from a SSN is important and surgeons must clarify exactly what they mean when discussing operations with patients. This could be done with the aid of pictograms or leaflets detailing issues discussed in consultations along with the opportunity to meet patients who have already had surgery. These measures may lead to increased patient satisfaction with surgery.

Ethics approval: Audit

Interest Statement: None

Background: It remains unclear and controversial whether preoperative magnetic resonance imaging (MRI) in patients with adolescent idiopathic scoliosis (AIS) should be mandatory.

Aim: (1) To review our own practice, (2) conduct a national survey of United Kingdom Consultants, and (3) to perform a literature review.

Methods: Our own practice was established by identifying patients with AIS and examining whether an MRI scan was performed preoperatively. A survey of Consultants practice in the UK (British Scoliosis Members) was conducted by either an e-mail or telephone conversation. Finally, a literature survey was performed to establish current views.

Results: 118 patients with AIS were identified between 2003 and 2007. 78% of these patients underwent pre-operative MRI scans. Neural axis abnormalities were found in 8% of these patients. They included syrinx’s, chiari malformations, tonsillar herniation, cord tethering, central canal dilatation and undiagnosed spina bifida. Only 1 patient required intervention by the neurosurgeons. 92% of respondents to the national survey routinely performed preoperative MRI scans. The literature was not conclusive with regards to mandatory preoperative imaging.

Conclusion: Despite the literature showing little evidence, our survey shows a widespread consensus in clinical practice across the UK that routine preoperative MRI should be performed from a risk management viewpoint. It is mandatory in our unit to perform pre-operative MRI scans on all patients with AIS and would recommend that this becomes standard practice in all other units.

Ethics Approval: None/Audit

Interest Statement: None

Introduction: One of the main factors in the success of impaction bone grafting (IBG) in revision hip surgery is its ability to resist shear and to form a stable construct. Bone marrow contains multipotent skeletal stem cells and we propose that in combination with allograft will produce a living composite with biological and mechanical potential. In this study we looked at whether coating of the allograft with type 1 collagen followed by seeding with human bone marrow stromal cells (hBMSC) would enhance the grafts mechanical and biological properties.

Methods: A control group of plain allograft and three experimental groups where used to determine the effects that collagen and hBMSC have on IBG. The samples where impacted in standardised fashion previously validated to replicate femoral IBG, and cultured in vitro for 2 weeks. The samples then underwent mechanical shear testing and biochemical analysis for DNA content and Osteogenic activity.

Results: In isolation, both Collagen coating and seeding with hBMSC significantly enhanced the mechanical properties of the construct compared to the ‘gold standard’ of plain allograft. This was further enhanced (p=0.002) when the two processes are combined both with shear strength (245 vs. 299 kPa) and cohesion between the graft particles (46 vs. 144 kPa). The collagen coated group also showed increased osteogenic cell proliferation.

Discussion: This study has shown a role in the improvement of the mechanical properties of IBG coated with collagen and seeded with hBMSC. Collagen coating of IBG is a simple process and translation of the technique into the theatre setting feasible. The improvement in shear strength and cohesion could lead to earlier weight bearing for the patients and allow quicker recovery. The therapeutic implications of such composites auger well for orthopaedic applications. We are currently strengthening the above findings with an in vivo study.

In a high-risk technically advanced speciality like spine surgery, detailed information about all aspects of possible complications could be frightening for the patients, and thereby increase anxiety and distress. Therefore, aim of this study was to

Analyze written evidence of the consenting procedure pertaining to (a) nature of operation (b) benefits intended as a result of the operation (c) risks specific to the particular type of operation (c) general risks of spine surgery and anaestheia.

Methods: 70 adult elective, consecutive patients who had been listed for Lumbar discectomy /decompression surgery were chosen. The patients were presented with questionnaire of broad-based and open-ended questions designed to elicit theirs views in each of the following areas: expectation, knowledge of risks and alternatives, and personal attitude to information and satisfaction.

The study had a non-randomized design and patients divided into TWO groups Group A and group B.

The patients in the group A received standard information and were consented in a routine way without being given written proforma with all complications. The patients in the group B were given the same information as patients in the control group, with written information about common and rare complications. Patients in both groups were assessed on an ‘impact of events scale’ and hospital anxiety and depression scale immediately before ad after the consent process and again after surgery when they were discharged from the hospital.

For comparison of the proportion of Yes and No answers in 2 groups, Fisher’s exact test was used, and for comparison of more than 2 groups, the Chi-square test was used. For graded answers and other ordinal scales, the Mann–Whitney U-test was used for comparison of 2 groups and the Kruskal–Wallis test for comparison of more than 2 groups. Spearman’s test was used when assessing the correlation between 2 variables measured on an ordinal scale.

Results: Many patients (71%) agreed that the consent form made clear what was going to happen to them, and 77%) reported that it made them aware of the risks of the operation they were to undergo. Over a third (36%) saw it as a safeguard against mixups in the operating theatre. Few patients’ decision to accept surgery appeared to depend on risk information; 8% of patients said that they might have changed their decision, had they been advised of the risks of permanent stroke and myocardial infarction. However, 92% were clear that their decision to accept treatment would not have altered. The women in the group B had symptoms of definite anxiety to a significantly higher degree than the men before the operation. Post-operatively, patients receiving extended information were significantly more satisfied with both the written and oral information about common and rare complications than patients in the control group There were no statistically significant differences between the groups for anxiety or depression, as measured by the HADS, either before or after the operation between Group A and B. Provision of extended information describing most of the possible complications did not have any negative effects on the patients. The patients receiving the extended information were more satisfied and experienced to a higher degree that they could discuss alternative treatment methods with the surgeon. Discussion: Provision of extended information describing most of the possible complications did not have any negative effects on the patients. “Ignorance is bliss” may prove to be an excellent preoperative strategy for patients when outcome is good but detrimental to long term adjustment where significant postoperative complications arise. This raises the possibility that a separate consent could be used where these risks are pre-printed and explained in vocabulary easily understood by patients. The added advantages of this form would be less confusion for the patient and there would be written evidence that patients had understood each of the major risks involved with the proposed procedure. This proposed consent form would also reduce the chance that important risks and complications are omitted when consent is being taken, as well as tackling the issue of variability of experience or lack of knowledge by the person obtaining consent.

Introduction: Scoliosis surgery involves major blood loss, at times exceeding estimated blood volume.

Aim: To evaluate the effects of implementing blood conservation strategies (including cell salvage, controlled hypotension and anti-fibrinolytic drugs) on transfusion requirements in adult patients undergoing scoliosis correction surgery. To establish a protocol for cross matching of blood.

Study Design: We retrospectively studied 50 consecutive adult patients who underwent scoliosis correction surgery (anterior, posterior or combined) between 2003 and 2007. All patients were anaesthetised by the same anaesthetist who implemented a standard transfusion protocol. Age, BMI, pre and post operative haemoglobin, levels fused, duration of surgery, hospital stay, antifibrinolytics used and blood transfused was noted.

Results: 50 patients with mean age 24.6 years and mean BMI 21.9 kg/m2 were studied. 14 patients had anterior surgery, 19 patients had posterior surgery and 17 had combined anterior and posterior procedures. Mean number of levels fused was 9.5 (6–15) and mean duration of surgery was 284.6 minutes (135–550 minutes). Anti-fibrinolytics were used in 31 patients (62%), Aprotinin in 21(42%) and Tranexamic acid in 10(20%). Mean blood loss in patients who received anti fibrinolytics was 530mls while mean blood loss in the other patients was 672mls. (p< 0.05). Blood transfusion was not required in any of the patients undergoing anterior correction only while 7 patients (41%) undergoing anterior and posterior correction and 3 patients (15.8%) undergoing posterior correction only required blood transfusion. Mean volume of cell saved blood re-transfused was 693.8 mls and mean hospital stay was 9.2 days. Mean pre-op haemoglobin was 13.2 g/dl (10.4–17.4) and mean post-op haemoglobin was 10.7 g/dl (7.7–15). 4 patients (8%) required intra and post-operative blood transfusion while 6 patients (12%) required blood transfusion postoperatively.

Conclusion: Use of anti-fibrinolytics like Aprotinin and Tranexamic acid reduces blood loss in scoliosis surgery. In the current scenario, with Aprotinin no longer available for use, our study would recommend the use of Tranexamic acid alongwith other blood conservation measures.

In our unit we do not have blood cross matched for anterior surgery alone.

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.

Introduction: Sacroiliac joint (SIJ) is a diarthrodial joint and can often be a source of chronic low back pain complex. We present a percutaneous technique for SIJ fusion and the functional and radiological outcome following the arthrodesis.

Aims and Objectives: To evaluate the functional and radiological outcome following percutaneous technique for SIJ fusion with HMA (Hollow modular anchor-age) screws.

Materials and Methods: 15 consecutive patients operated for SIJ fusion between Sep 2004 and Aug 2007 were included in the study. The diagnosis was confirmed with MRI and diagnostic injections. Pre-operative and post-operative functional evaluation was performed using SF-36 questionnaire and Majeed’s scoring system. Postoperative radiological evaluation was performed using plain radiographs. The Hollow modular anchorage (HMA) screws (Aesculap Ltd, Tuttlingen) packed with bone substitute were implanted percutaneous under fluoroscopic guidance

Results: The study group included 11 females and 4 males with a mean age of 48.7 years. Mean follow-up was 14 months. Mean SF-36 scores improved from 37 to 80 for physical function and from 53 to 86 for general health. The differences were statistically significant (Wilcoxon signed rank test; p < 0.05). Majeed’s score improved from mean 37 preoperative to mean 79 postoperative. The difference was statistically significant (student t test, p< 0.05). 13 had good to excellent results. The remaining 2 patients had improvement in SF-36 from mean 29 to 48. Persisting pain was potentially due to coexisting lumbar pathology. Intra-operative blood was minimal and there were no post operative or radiological complications in any patient.

Conclusion: Percutaneous HMA screws are a satisfactory way to achieve sacro-iliac stabilisation.

Background: Radicular pain has been reported even in the absence of a compressive lesion. It has been postulated that annular tears provide a conduit for pro-inflammatory substances, which can leak around the nerve root causing radiculitis. A link between the side of back pain and the side of the annular tear has been reported.

Objective: To establish whether the side of the annular tear may influence the side of the leg in a non-compressive setting.

Methods and patients: We identified 121 patients from the patients referred to our unit with back and radicular leg pain. The mean age of the cohort was 50 yrs and 49% were male. All these patients were investigated with an MRI scan that demonstrated no compression of the nerve root. We used strict exclusion criteria to exclude the patients with any neural compression, previous lumbar operation, degenerative deformity or an associated pathology such as peripheral neuropathy.

Results: The annular pathology was described as annular tears (47 patients) and non compressive disc bulges (106 patients). The odds ratio for the concurrence of an annular tear causing ipsilateral leg pain is 1.05 and for a non-compressive disc bulge causing ipsilateral leg pain is 2.14

Conclusion: A non-compressive disc bulge is more likey to cause radicular symptoms than an annular tear. Though, both these annular lesions can cause ipsilateral nerve root symptoms.

Anterior Lumbar Interbody Cages are used to recreate the lumbar lordosis in scoliosis surgery as anterior instrumentation is usually kyphogenic. We report two cases in which an anterior release was performed and interbody cages were used.In both these patients the cage was displaced anteriorly by an incorrectly positioned pedicle screw during posterior instrumentaion. In one case the cage was retrieved and correctly repositioned from the back using a TLIF approach, in the other this was noticed only post-operatively and patient needed another anterior surgery. We recommend a lateral Image Intensifier screening for combined anterior and posterior cases in which anterior cages are used in addition to posterior pedicle screws to prevent this complication.

Objective: To assess the correlation between the side of the annular pathology and the radicular symptoms, in the absence of a compressive root lesion.

Materials and Methods: 121 patients underwent MRI scan fro axial back and radicular symptoms. The mean age was 49.9 yrs (24–80). The sex distribution was equal. We excluded the patients that had a compressive lesion, previous operations, spinal deformity, spondylolyses, an underlying pathology (tumour, trauma or infection) or a peripheral neuropathy. Annular pathology was documented as annular tear or a non-compressive disc bulge with its location and side. We also recorded marrow endplate changes and facet arthrosis.

Results: Bilateral radicular symptoms were reported in 16 (13.2%): right side in 33 (27.3%) and left in 47 (38.8%) patients. Additionally, 82 patients (67.8%) had axial back pain. 33 patients (27.3%) were noted to have a right sided annular pathology (tear or bulge) and 72 (59.5%) had a left sided annular lesion. 21 patients (17.4%) had a central annular tear and 43 (35.5%) had a generalised disc bulge. 14 patients (11.6%) with right sided symptoms also had annular pathology, while 38 patients (31.4%) with left sided symptoms had a left sided annular lesion. There was no statistical correlation between the side of symptoms and the side of the lesion (r = −0.00066, p=0.994), any particular annular pathology (annular tear r=0.085, p=0.35; disc bulge r-0.083, p=0.36). There was no correlation between the axial back pain and the annular pathology (r=0.004; p=0.97) and facet joint or marrow end plate changes (r= −,29, p=0.76).

Conclusions: Although annular pathology can cause the radicular symptoms, our results suggest that they do not influence the side of the symptoms.

Objective: To assess the temporal geometric sagittal profile changes on serial radiographs of fractures of the thoracic and thoraco-lumbar spine.

Materials and methods: We have included 103 patients with thoracic or lumbar fractures were treated at our unit between June 2003 and May 2006. The patients were suitable for non-operative treatment. The mean age of the cohort was 46.9±2.4 (16–90). The sex distribution was equal. 94 patients had a single level lesion. 19 fractures were in the thoracic spine; 64 in the thoraco-lumbar (T11-L1) and 29 between L2 and L5. The radiographs were scored using the AO classification by 2 senior orthopaedic trainees. The radiographs were analysed at the Spine Research Laboratory. The results were computed using Stat, a statistical software.

Results: The changes were assessed over a mean period of 5.6 mo (range 1–49 mo; 95% CI 4.1–7.1 mo). Weighted kappa score of 0.58 was computed for the primary fracture type and 0.22 for the fracture sub-types. The inter-observer rater agreement was similar to that reported in literature. 7 patients showed a significant collapse. We report the association between the fracture types and the extent of collapse. We have also assessed the association between the medium to long term symptoms, the fracture types and the extent of collapse at the fracture sites and the adjacent disc.

Conclusion: Some fracture sub-types are more likely to collapse and cause long term symptoms. Identifying these fractures at the outset would help clarify surgical indications.

Objective: To do assess changes in patients’ symptoms and the operative plan.

Materials and methods: 147 patients on a spinal surgery waiting list were assessed at a mean wait of 15.8 ± 1.3 months. 89 (61%) were male and 58 (39%) were female at a mean age of 49.7 yrs (16–78). 123 patients had a degenerative condition (20 cervical; 03 lumbar); 20 patients were seen for scoliosis; 2 with a post-traumatic kyphosis and 1 each with ankylosing spondylitis and a psudarthrosis.

Outcomes assessed: Changes in patients symptoms; changes from the initial operative plan when listed; requirement for re-imaging due to the wait.

Results: 31 patients reported improved symptoms at the re-assessment, while 96 were worse off and 20 were unchanged. 137 had axial pain when listed which changed to 116 at review (p=0.0018). 130 had radicular pain when listed which improved to 80 on re-assessment (p< 0.0001). However 19 reported an increase in the axial and 17 in the radicular symptoms. 71 patients (48.3%) required to be re-imaged at the re-assessment due to changes in the clinical picture. 42 patients received the procedure as originally listed. 30 patients were taken off the list, 24 received a different operation, and 38 had an interim or a definitive needling procedure while 13 await a re-assessment.

Conclusions: On the basis of the observations on our cohort, 1 in 5 operations were cancelled; 65% had an increased severity of the symptoms and just 1 in 3 patients were operated as planned while 48% required re-imaging. A long wait inevitably leads to changed symptoms and a review of these patients is mandatory. The review and the re-imaging adds to the burden on the already over-loaded system.