Introduction: Multiple classification systems for avascular necrosis of the hip have been developed to assist physicians in the diagnosis and treatment of this potentially debilitating disorder. However, this lack of consistency makes clinical decision making difficult when comparing publications. The purpose of this study was to quantify the classification systems reported since 1985 (post-MRI) and identify consistent factors which would allow cross-publication comparisons to be made.

Materials and Methods: The authors performed a PubMed search for reports of outcome studies concerning treatment methods of hip avascular necrosis that were the initial basis for analysis. All studies reported since 1985 were included in the analysis if outcomes of greater than 10 patients treated for this disease were reported. Classification systems utilizing at least one factor were also identified. Tabulation of how frequently these classification systems were used in terms of the number of studies reporting results was performed.

Results: Fifteen major classification systems utilizing more than one radiographic factor were identified with 9 having one to three modifications reported throughout the literature. Additionally, 14 systems utilized either MRI or anatomic factors. Cross-publication analysis revealed five major classification systems which were utilized in greater than 80% of the reported studies.

Discussion: This analysis of the reported classification systems for avascular necrosis of the femoral head revealed several similarities between systems. A cross system analysis can be made if data is collected according to patient symptoms, magnetic resonance imaging findings, and x-ray findings which would allow for the use of any staging system.

Introduction: Evidence-based medicine is a form of practice in which the physician accesses relevant, state-of-the-art research findings to guide the care of the individual patient (Gordon and Cameron, 2000). Therefore, evidence-based medicine should influence the decision making process when developing a treatment algorithm for early stage osteonecrosis. It was the purpose of this project to explore the literature concerning surgical options that are used currently to treat early stage osteonecrosis.

Materials and Methods: Literature searches were conducted using PubMed (National Library of Medicine, USA) to identify journal articles pertaining to the treatment of pre-arthrosis osteonecrosis during the past decade. The articles were screened to include only those with greater than 5 patients and greater than two year follow-up.

Results: Published reports in medical journals included: core decompression with and without nonvascular grafting (18); core decompression augmented with BMP or bone marrow cells (2); bone cement (1); vascularized graft – fibular or iliac (10); osteotomy (26); osteotomy and vascularized grafts (3); trap-door procedure (2); and hemiarthroplasty/resurfacing arthroplasty (9). There was one review of nonoperative treatment, but no clinical studies. There were only a few case reports concerning osteochondral graft/osteochondroplasty; which did not meet the inclusion criteria. Several classification systems were used: Ficat and Arlet (55%); University of Pennsylvania / Steinberg (21%); Japanese Investigational Committee (13%); Marcus (2%); Myers (3%); ARCO (5%), and other (1%). A majority of reports included follow-up of 5 years or greater (91%). Most studies (91%) were not randomized, control-matched, or prospective.

Discussion: Several surgical options are available for the treatment of pre-arthrosis osteonecrosis. However, it is not possible to apply evidence-based medicine practices to the research relating to the treatment of osteonecrosis as most of the research is not controlled and not comparative. This represents a substantial void in our knowledge base concerning osteonecrosis which remains to be filled.

Introduction: Chondrosarcoma is the second most common malignant solid tumour of bone. The management of extra-axial low grade chondrosarcomas remains a controversial issue. Many groups advocate wide excision, necessitating substantial reconstructive surgery, often requiring massive endoprostheses or allografts. Our unit favours intralesional curettage, as it is less invasive and results in smaller defects affecting only the medulla, which can be reconstructed using simpler methods. The purpose of this study was to assess the oncological and functional outcomes of this treatment strategy.

Methods: Using our database, we identified patients with long bone chondrosarcoma that had undergone intralesional curettage between 1999 and 2001. The resultant defects had been filled with PMMA cement in 22 cases and bone graft in 2 cases. A review of all notes and radiographs was performed, with functional assessment of all available patients using the Musculoskeletal Tumour Society Scoring (MSTS).

Results: 24 consecutive cases were identified; 11 cases affecting the distal femur, 8 in the proximal humerus, 3 in the tibia and 1 each of the scapula and radius. Average age was 47 years, (range 22–75). Tumour grade was: grade 1 – 22 cases and grade 2 in 2 cases. Mean follow-up was 52 months, (range 38–73 months). There was a single case of local recurrence in a patient that had a grade 2 lesion; there were no incidences of metastases. Functional outcome was assessed in 20 of the 23 remaining cases, scoring a mean 93.7% (range 53–100) on the MSTS.

Conclusion: This study suggests intralesional curettage is an effective treatment strategy for extra-axial low grade chondrosarcoma with excellent oncological and functional results. Careful case selection, with stringent clinical and radiographic follow-up is recommended.

Background: Although either anterior or posterior corrective scoliosis surgery has been reported in Jehovah’s Witnesses, we did not find any reports of single stage combined anterior and posterior scoliosis surgery being done in these patients. We report our experience in one such case.

Methods: This is a case report of a 14 year old female Jehovah’s Witness who had cerebral palsy with total body involvement presented with right sided thoracolumbar scoliosis. She was wheel chair bound and was being treated in a spinal brace. She had a partially correctible thoracolumbar curve from T5 to L2 measuring 94°, which reduced to 74° in brace. Her parents were counselled regarding scoliosis surgery. They consented for the surgery and also signed a special consent form for Jehovah’s witnesses specifying that they would prefer their child not to have transfusion of blood or blood products under any circumstances. They were explained that in case of excessive bleeding, further surgery may need to be deferred.

Results: Although her pre-op Haemoglobin was 14.3 g/dl, she was given oral ferrous sulphate because of low serum ferritin level (34 mcg/L). After induction of anaesthesia, intra operative hemodilution was performed using 900 ml of crystalloid. During surgery aprotinin infusion was used with controlled hypotension and cell salvage. Anterior release was performed followed by posterior instrumentation. The operation lasted for 8 hours. Central venous pressure and arterial oxygen saturation remained stable throughout the operation. She recovered well following surgery, with post-operative haemoglobin of 9.8 g/dl and was discharged on the7th post-operative day. Oral iron supplementation has been continued after surgery.

Conclusion: Due to religious reasons, Jehovah’s Witnesses do not accept transfusion of blood and blood products, which makes major surgery like scoliosis correction difficult as it involves a significant amount of blood loss. Such patients benefit from pre-operative iron supplementation, pre-operative haemodilution, intraoperative hemodilution, cell salvage, use of Factor 7, aprotinin and erythropoietin. These modalities have made it possible to perform major operations like scoliosis surgery in this group of patients.

Background: There are conflicting reports regarding the effect of scoliosis surgery on respiratory function in Duchenne Muscular Dystrophy (DMD)^1,2. Galasko et al² found that the Percentage Predicted Forced Vital Capacity (%PFVC), remained static for thirty six months following surgery, in patients with DMD that underwent spinal stabilisation for scoliosis. The aim of the current study was to support or refute the above finding in a large series of patients with DMD.

Methods: A retrospective analysis of data on 55 consecutive patients with DMD that underwent single stage posterior surgical correction for scoliosis. We analysed the data of 55 boys with DMD who underwent scoliosis surgery between 1990 and 2002. Age at surgery, pre-operative Cobb angles, pre-operative %PFVC, and post-operative %PFVC at 6 months, 12-18 months and 2–3 years were collected. We documented the pre-operative Cobb angle ± SD to assess the difficulty level of our surgical cases. Percentage PFVC was used as our outcome measure to assess respiratory function. The mean pre-operative %PFVC was compared to the post –operative mean %PFVC at three different time intervals; at 6 months, 12 to 18 months and at 2 to 3 years.

Results: The mean age was 14.6 years (range 11.2–18yrs). The mean pre-operative Cobb angle was 65.4 degrees ± 14.8. The mean %PFVC pre-operatively was 33.9 ± 10.4. The mean post-operative %PFVC’s were: 6 months (29.1 ± 10.4), 12 to 18 months (27.6 ± 12.1) and 2 to 3 years (25.4 ± 8.7). Therefore the mean % PFVC following surgery at 6 months, 12 to 18 months and 2 to 3 years decreased from the mean pre-operative % PFVC by 4.8%, 6.3% and 8.5% respectively.

Conclusion: The natural history of patients with DMD is a gradual decline in respiratory function. In the current study the mean post –operative %PFVC was less than the mean pre-operative %PFVC at 6 months, 12 to 18 months and at 2 to 3 years post surgery. Our series would suggest that respiratory function declines post-operatively, even in the short term, in patients with DMD that undergo spinal stabilisation. The decline in respiratory function in our study was progressive over the 3 year follow up period.

To investigate the diagnostic properties of magnetic resonance imaging (MRI) scans in detecting surgically verified disruptions of the cervical intervertebral disc and anterior (ALL) and posterior longitudinal (PLL) ligaments.

Data were extracted from the reports of cervical spine MRI scans of patients who subsequently underwent surgical stabilization for presumed instability following disco-ligamentous injuries of the cervical spine. The level and severity of disc, ALL and PLL disruption was compared with surgical findings. Unweighted kappa statistics were used to assess agreement. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were calculated after findings where dichotomised into complete rupture, yes/no. Sensitivity analyses were performed to account for missing data.

The MRI and surgical findings were compared on 31 consecutive patients. The kappa values for intervertebral disc disruption, ALL and PLL disruption were 0.22, 0.25 and 0.31 respectively, indicating fair agreement. Sensitivity, specificity, PPV and NPV are shown in Table 1. The false negative rates for diagnosing complete disruption of the disc, ALL and PLL were 0.18, 0.40 and 0.14 respectively.

The ability of cervical MRI scans to detect surgically verified disruptions of the intervertebral disc, ALL and PLL varied depending on the structure examined. In this series, the cervical MRI scan reliably detected disruption of the intervertebral disc disruption and ALL. The false negative rates are of concern and indicate the need for additional investigations to exclude instability in the absence of negative MRI findings.

Introduction: In a previous study (ARCO, 2002), we reported that the clinical results of revision total hip arthroplasty for osteonecrosis patients were less satisfactory than those found for a matched group of osteoarthritis patients. The aim of this study was to evaluate the potential factors that may have contributed to these findings.

Materials and Methods: This study included 34 hips in 30 osteonecrosis patients who had undergone revision of a femoral total hip arthroplasty component. There were 19 men (22 hips) and 11 women (12 hips) who had a mean age of 46.1 years (range, 28 to 69 years). The surgeries were performed between March 1984 and January 2001. Most femoral stems (91%) were implanted without cement. Prostheses were of different stem lengths, but most (97%) were proximally porous-coated. The mean follow-up was 8.2 years [range, 0.1 (a re-revision) to 19.8 years]. A physical examination as well as patient and physician outcome forms were collected at each visit. Preoperative x-rays were categorized according to the technique of Della Valle and Paprosky. A Kaplan-Meier survival analysis was performed (PEPI statistical software package).

Results: Risk factors for osteonecrosis included 15 corticosteroid, 8 alcohol, 7 trauma, and 4 unknown. This was the first revision in 27 cases, second revision in 5 cases, and third revision in 2 cases. Preoperatively, the defects included 4 Type I, 9 Type II, 15 Type IIIA, 2 Type IIIB, 1 Type IV, and 3 unknown types. Of the 34 hips, the femoral component was re-revised in 12 cases. One of the failures was the only fully porous coated stem that was implanted. One of the 3 cemented implants failed, as compared to 11 of the 31 implanted without cement. Survival rates were 90.9% (74.4%–97.1%) at 5 years, 54.8% (24.9%–81.6%) at 10 years, 54.8% (19.9%–85.6%) at 15 years, and 27.4% (1.7%–88.9%) at 20 years. There was no relationship between frequency of re-revision and defect category, risk factors, or age.

Discussion: Although there was a high failure rate (12/34; 34%) in this patient cohort, over 50% survived at least 10–15 years. The lack of a relationship between the patient age or the extent of defect and re-revision suggest that other factors concerning this disease need to be examined.

To reduce the disability after hip disarticulation customised endoprostheses have been used in our unit to preserve a proximal femoral above knee amputation stump. This procedure involves preservation of a musculocutaneous flap and insertion of a customised stump prosthesis that articulates with the acetabulum. This procedure has been performed not only for primary malignancy but also in the reconstructive setting. Six patients have undergone the above procedure with a good functional outcome-allowing mobilisation with an appropriate orthosis. We will discuss the complications of such a procedure that includes disassociation of the femoral head from the customised prosthesis.

We present the technique as a useful adjunct not only in the treatment of large proximal femoral tumours but also in the end stage reconstructive setting.

Introduction: (1) Determine whether initial MRI findings correlate with clinical outcome.(2) Study the reproducibility of MRI measurements of large disc prolapses.(3) Estimate the ability to predict CES based on MRI alone.(4) Does CES only occur in degenerate discs?

Method: 31 patients with CES were identified and invited to attend clinic. 19 patients who underwent discectomy were identified. Digital photographs of all 50 MRIs were obtained. Observers: 1 Radiologist, 2 Spinal Surgeons and 1 Trainee did not know the number of patients in each group. Observers estimated the percentage spinal canal compromise on each view (0–100%), indicated whether they thought the scan findings could produce CES and commented on disc degeneration. Measurements were repeated after 2 weeks.

Results: 26 patients attended clinic – mean follow up 51 months (range 25–97). 12 of the 26 patients with CES had, on average, > 75% canal compromise. No significant correlations were found between MRI canal compromise and clinical outcome. Kappa values for intra-observer reproducibility of measurements ranged from 0.4–0.85 and inter-observer 0.63–5. Based on MRI, the correct identification of CES has sensitivity 68%, specificity 78%, positive predictive value 84% and negative predictive value 58%. Over 80% of the CES causing discs were degenerate.

Discussion: Canal compromise does not appear to predict clinical outcome. MRI measurement reproducibility has substantial agreement. CES is a clinical diagnosis supported by an MRI scan. In less clear cases the presence of a large disc on an MRI scan supports a diagnosis of CES (PPV 84%). CES occurs in degenerate discs.

Purpose Coagulase negative staphylococci (CNS) have been one of the major pathogens responsible for prosthetic joint infections, and are showing increasing multiple-antibiotics resistance. Intact cell mass spectrometry (ICMS), based on the analysis of bacterial surface proteins, has been recognised as a new technique for identification of micro-organisms. The aim of this study was to evaluate the ability of ICMS for species level identification of clinical CNS isolates.

Method A total of 50 CNS strains from revision joint replacement operations were studied. ICMS and commercial identification kits were used for identification of those CNS. The commercial kits were used following the manufacturer’s recommendations. For ICMS, single colonies were smeared onto five spots on a sample slide. After drying, a 1 μl of aliquot of matrix solution was added to each spot. Analysis of strains was performed using a Kompact MALDI 2 linear, time of flight mass spectrometer and 3-ns pulse width nitrogen laser light. Combined spectra were constructed from 100 shots at each spot on the sample slide.

Results In this study, the commercial kit did not require any special equipment, but required overnight incubation and could not identify at least seven strains. On the other hand, the ICMS method was rapid, accurate and highly reproducible. The mass: charge spectra produced by ICMS contained potential biomarker peaks that could be used for species level identification.

Conclusions ICMS has the potential as a powerful tool for species level identification of clinical CNS isolates in terms of rapidity, accuracy and cost effectiveness. This study suggested that ICMS is a possible new method of identifying causative organism in infected joint replacements.

Background: Campbell et al from Texas have pioneered the use of Vertical Expandable Prosthetic Titanium Rib (VEPTR) in congenital scoliosis. Our centre is the first in the UK to use it and we report our experience of 5 cases done in the past 2 years. VEPTR works on the principle of expansion thoracoplasty and thoracic spinal growth of upto 0.8 cms/year has been reported by the developers of this device.

Methods: This case series includes one child who had the index surgery in America and is undergoing sequential expansion in Cardiff. All surgeries were done using a standard technique with monitoring of somatosensory evoked potentials. After appropriate soft tissue and bony releases, VEPTR was inserted and expanded by 0.5 cms to maintain tissue tension. Subsequent expansions were done as day case surgeries at 4–6 month intervals through a small incision over the VEPTR. We assessed clinical and radiographic assessment, which included – hemithorax height ratio, Cobb angle, interpedicular line ratio, space available for the lung.

Results: There were 3 males and 2 females with mean age of 6.3 years (range 0.9 to 9 years) at the time of index operation. Average follow up is 2 years (0.4 to 5 years). Average hospital stay for the index surgery was 5 days (4–7 days). All patients had mean of 3 expansions (range: 0–6). Mean improvement in the Cobb angle was seen from 48° to 36° at last followup. Space available for lung improved from a mean of 72 % to 86 %. Mean improvement in hemithorax height ratio was from 72.5% to 86%. One child had mild pain due to prominent metalwork; 2 children had transient brachial plexus neurapraxia, one of whom had progression of a secondary cervical curve and is awaiting further surgery for the same.

Conclusion: Our early results show good improvement of clinical and radiographic parameters. Transient nerve palsies have been well reported on the concave side and occur due to traction on the nerves as a result of increased height of the thoracic cage. This occurred in one initial case and has not been seen later. These results are encouraging but do indicate a learning curve.

Aim: To present and highlight a remote complication following deep x-ray radiotherapy to Ilium.

Background: Radiotherapy is one the options to treat malignancy. Surrounding normal tissue can be affected by super-imposed infection, radiation-induced tumors, and other complications of radiation therapy. Timing of radiation changes varies in the different organs. Acute radiation pneumonitis is generally seen approximately 2 months after completion of radiotherapy, but radiation pericarditis not until 6–9 months after therapy. Radiation-induced sarcomas do not develop on average until 10–15 years after radiation therapy.

Case report: A 39-year old presented to an oral surgeon 29 years ago with a submandibular swelling that was gradually increasing in size. Excision biopsy revealed Follicular, Large cell, Non-Hogdkin’s Lymphoma. Lymphogram showed positive nodes in pelvic and para-aoric regions. She was treated with chemotherapy initially. She developed left SI joint pain 2 years later and was treated with radiotherapy. The lymphoma later became chemotherapy resistant and the patient was treated with whole body irradiation. She was in remission since 26 years. She started having discomfort in the left hip region far past 5 years and was reviewed. A recent MRI scan revealed avascular necrosis of the femoral head with little collapse. Changes in the ilium and muscle wasting around the left iliac wing were noted, which were consistent with post radiation osteonecrosis.

This lady noticed a recent change in the gait and examination revealed positive trendelenberg test and a lurching gait. Latest radiographs have shown a fracture of the left iliac crest. The patient did not request any surgical intervention and was reassured with explanation.

Conclusion: Post radiation osteonecrosis can cause complications as late as 26 years following deep x-ray radiotherapy.

The aim was to audit the numbers of non-residents requiring orthopaedic admission to our hospital and determine the effect of increasing tourist numbers and changes in Accident Compensation Corporation (ACC) regulations on health care resources.

Details of non-resident orthopaedic admissions for fiscal years 1997/8 to 2003/4 were analysed with respect to country of residence, mechanism of injury, case weights consumed and actual costs.

There has been no change in numbers of admissions or cost averaging 32 cases (50 case weights) per year over the 7 year period. Most patients came from Asia (59 cases, 26%), then Australia (52 cases, 23%) and UK (40 cases 18%). Snowsports accounted for 40% of admissions, Motor vehicle accidents (MVA)17% and falls 29%.

Non-resident, non-MVA admissions have averaged 21 CW per year since the changes in ACC regulations in 1999.

Despite increasing tourist numbers there has been no increase in numbers or CW of non-residents requiring orthopaedic admission. Although representing only a small proportion of the orthopaedic budget they generate many hidden costs. The 50 CW annually equates to approximately 13 major joint replacements per year. The increase in CWs consumed due to the ACC changes have had no corresponding increase in contracted orthopaedic volumes.

Purpose: To quantify the functional outcome of patients who were known to have sciatic nerve involvement pre-operatively and went on to have nerve preserving surgery utilising a planned marginal excision with epineurectomy.

Materials and Methods: Ten patients with large volume posterior thigh soft tissue sarcoma with known sciatic nerve involvement were reviewed between 1997 and 2004. Nine underwent surgery with extended epineurectomy of the sciatic nerve and planned marginal excision.

All patients underwent staging and follow up at Sarcoma Clinic with functional assessment and TESS evaluation.

Results: There were seven low and two high grade posterior thigh tumours of which nine were liposarcoma and 1 haemangiopericytoma. Two were recurrent and eight primary. There were five men and five women with a mean age of 77.

Nine patients underwent planned marginal excision. Sciatic nerve involvement was 13–30cm in eight cases and in one case the sciatic nerve was abutting the tumour throughout its length. There was soft tissue reconstruction in three cases using fascial adductor or gracilis graft for sciatic nerve cover and one with superficial femoral nerve and vein resection requiring ipsilateral saphenous reconstruction. The remainder underwent direct primary reconstruction.

Four patients underwent radiotherapy 46–60 Gy.

There was no local recurrence of disease within 14 – 96m follow-up. There was one patient with post radiation wound breakdown that resolved.

Three patients have died of unrelated causes. To date there has been no evidence of local recurrence of disease at FU.

Conclusion: Planned marginal excision of low grade large volume posterior thigh sarcomas with extensive sciatic nerve involvement can be successfully treated with preservation of the sciatic nerve without significant morbidity and resultant good limb function.

Aim: To review our series of mid foot sarcomas with regard to excision of tumour, tolerance of radiotherapy and preservation of function.

Methods and results: We identified 6 patients with mid foot sarcomas treated in our unit. Synovial sarcoma was the commonest diagnosis. All the patients had stage 1 disease with no evidence of pulmonary metastases at presentation. Patients judged to have resectable tumour but preserving sufficient foot to be functional were spared amputation. They had excision of the sarcoma and immediate reconstruction using fascio-cutaneous free flaps. Complete excision was achieved in all cases. One flap was lost and repeated. In all patients, subsequent radiotherapy was well tolerated without significant complications. All patients remain disease free. All patients have returned to pre-operative functioning including walking and jogging. All except one have returned to work.

Conclusion: Patients and feet treated by wide local excision of mid foot sarcomas and reconstructed by free fascio-cutaneous flaps tolerate post-operative radio-therapy well, and return to near normal function.

The aim of this study was to prospectively audit the results of carpal tunnel decompression using a subjective patient derived outcome score (modified Boston Symptom Severity Score) and to examine the relationship between symptom severity scores and nerve conduction studies.

Prospective cohort study of all patients undergoing open carpal tunnel decompression at Dunedin Hospital over a 13-month period from December 2003 – January 2005. Demographic details collected included age, sex, duration of symptoms, diabetes, occupation and ACC status. Pre-operative investigations consisted of nerve conduction studies and a modified version of the Boston Symptom Severity Score developed for this study. Symptom severity scores were reassessed six months post-operatively.

One hundred and ten patients participated in the study. Mean pre-operative Boston Symptom Severity Score was 3.35 (1= normal, 5=severe). Post-operatively this improved to mean 1.66, median 1.45. Ninety three percent of patients were “very satisfied” or “satisfied” with their results. Age and duration of symptoms were not significant predictors of poor outcome.

The majority of patients undergoing carpal tunnel decompression were satisfied with the outcome and had excellent or good outcomes as determined by symptom severity score. The use of preoperative nerve conduction studies help in diagnosis and prognosis.

Aim: To investigate and compare the effects of two types of LCS total knee arthroplasty AP glide {(posterior cruciate is retained and the mobile bearing allows anteroposterior and well as rotational movement) and RP (in which posterior cruciate is sacrificed and the mobile bearing allows only rotational movement)} on joint proprioception and range of motion.

Methods: 30 patients scheduled to undergo mobile bearing total knee arthroplasty were randomised to receive either a LCS AP glide or Rotating platform prosthesis. Clinical scores (Oxford knee score, American knee society score (AKSS), EuroQol), range of motion and proprioception were assessed prior to and at three and six months after the operation. Proprioception was assessed in terms of absolute error angle (mean difference between the target angle and the response angle). Student’s t-test was used to compare the mean of two groups (with a level of significance of p < 0.05).

Results: Both groups were comparable in terms of pre-operative range of motion, oxford knee score, American knee society score, EuroQol score and proprioception. At 6 months there was significant improvement in the Oxford knee score, AKSS and EuroQol score in both groups (p< 0.001), but no difference was noted between the two groups with respect to these parameters. There was improvement in the proprioception (reduction in absolute error angle) in both groups though this was not significant statistically (p> 0.05). The mean active non-weight-bearing range of motion improved in both groups {AP glide group, (p< 0.05) and RP group, (p> 0.05)}

Conclusions: We did not find significant difference between AP glide and RP LCS knee arthroplasty in terms of improvement in proprioception and range of motion.

Background: Long waiting lists in the NHS are a cause for public concern especially with regards to progressive conditions like scoliosis. We reviewed records to 61 patients to ascertain whether waiting time had any detrimental influence on their surgical management.

Methods: Retrospective review. Assessment of clinical records and radiographs of 61 patients who had scoliosis surgery over past two years was done by two independent investigators. Patient demographics, waiting times between referral and outpatient review and waiting time for surgery were collected.

Results: There were 41 females and 20 males with mean age of 11.8 years (range, 1– 22 years). Thirty-four patients had thoracic curves (28- right sided), 21 had thoracolumbar curves (19- right sided) and 6 patients had right sided lumbar curves. Mean Cobb angle at presentation was 58° (range,17°–90°) which increased to 71°(range, 30°–120°) at surgery. Average waiting time to be seen in the clinic was 16 months. Average waiting time for surgery was 10 months. Rapid curve progression was seen in twelve patients (20%), of which 10 required more extensive surgery than originally planned. Their mean Cobb angle at presentation was 48° (range, 45°– 80°), which increased to a mean of 59° at surgery (range, 50°–92°). At presentation their Risser grades were: 5 – grade 0, 3- grade 2, 2- grade 4. These 10 patients had waited averagely 7.8 months to be seen in the clinic and for 11 months to have the surgery.

Conclusion: Significant curve progression occurred in 20 % of patients waiting to have scoliosis surgery. Ten of those required much more extensive surgery than originally planned. Long waiting times therefore have a detrimental effect on the surgical management of scoliosis patients.

Background: Fracture neck of the femur (NOF) is one of the indications for Total Hip Replacement (THR). However, the practice is not the same throughout the world.

Aim: We compared the use of THR in the management of the fracture NOF using the annual reports of the National Joint Registries from various countries.

Material and Methods: We used the latest available on line annual report of seven national arthroplasty registries to ascertain the rate of use of THR for fractures of the neck of the femur. The registries from Australia, Canada, Norway, Sweden, and the UK gave a detailed breakup of the indications for THR in their reports.

Results: 11.9% of the all the THRs performed in Norway since 1987 were for NOFs. · 11.39% of all the THRs performed in Sweden since 1992 were for NOFs.

6.0% of the THRs performed in Canada in 2002–2003 were for NOFs.

The registries from Finland and New Zealand had no detailed information on their websites regarding the indications for THA surgery.

Discussion: In the Scandinavian countries, THR is performed for the management of a NOF 6 times more often than in the UK, and 4 times more often than in Australia. It is unlikely that the prevalence of patients with previous osteoarthritis of hip who sustain a NOF is higher in the Scandinavian countries than in the UK. Women in Sweden have a higher lifetime risk of hip fracture and live longer, so a procedure providing a good long term results would be beneficial. Provision of health care may also influence surgical management options. The long waiting lists for elective THR in the UK may explain the low number of THRs performed for NOFs.

Background: A 9- year-old child with osteogenesis imperfecta and severe cervical kyphosis associated with wedged vertebrae and progressive neurological deterioration is presented. There is no report of upper cervical kyphosis associated with wedged vertebrae in osteogenesis imperfecta in the literature. We discuss the methods and difficulties in the surgical management of this condition and to highlight the appropriate surgical approach.

Methods: Methods:A 9-year-old girl presented with progressive cervical kyphosis and quadriparesis. At the age of 3 years she underwent posterior cervical fusion (C1–C6) for instability and deformity. Radiological and laboratory investigations confirmed the diagnosis of osteogenesis imperfecta. Radiographs of the cervical spine revealed a kyphotic deformity of 120° Magnetic Resonance Imaging (MRI) and Computerised Tomography (CT) scans showed anterior cord compression due to wedged vertebrae at C3 and C4. MRI-Angiography was performed pre-operatively to identify the anatomical position of the vertebral arteries. A modified anterolateral approach to the upper cervical spine was performed. Anterior C3 and C4 corpectomies with interbody fusion with cage and plate fixation was carried out.

Results: Postoperatively the patient made a full neurological recovery and significant correction of the deformity was achieved and correction was maintained at final follow-up.

Conclusion: Cervical kyphotic deformity in Osteogenesis Imperfecta is uncommon. Association of this condition with wedged vertebrae is rare. Surgical decompression of the upper cervical spine with severe kyphosis is a challenging problem. Which surgical approach should be used is controversial? There are difficulties exposing wedged vertebrae by a standard anterior or chin split approach to perform vertebrectomy. Costo-transversectomy has been used successfully in patients with Gibbous deformity in the thoracic spine but due the presence of vertebral artery in the cervical spine posterolateral approach is impossible. We have used a modified anterolateral approach to overcome this problem. Spinal stabilisation in children with Osteogenesis Imperfecta and poor bone quality is another challenge. We have used a small diameter MOSS cage with maxillofacial plate and screws to achieve stabilisation and fusion. The purpose of this report is to highlight the importance of diagnosis of progressive cervical kyphotic deformity in children with osteogenesis imperfecta and also to describe the difficulties encountered with surgical management of this condition.

Background: Type II odontoid fractures are the commonest upper cervical spine injury in the elderly, following minor falls. Structural heterogeneity within the axis with deficiency of bone mass in the base of the odontoid process has been attributed for these fractures.

Aims: To analyse whether osteoporosis at the dens-body junction is directly related to the occurrence of odontoid fractures in the elderly.

Material and Methods: We studied the reformatted CT scan images of 36 patients over the age of 70 years who had cervical spine injuries following minor trauma. In all these patients the severity of osteoporosis at the dens-body junction, and in the peg and body of axis were evaluated. The osteoporosis was graded into none, mild, moderate and severe. Statistical analysis was performed using Pearson’s Chi-square test to find the significance of osteoporosis at the dens-body junction in producing Type II odontoid fractures in the elderly.

Results: Type II odontoid fractures was seen in 21 patients. Eleven of the 21 patients with Type II fractures and eight of the 15 patients with no Type II odontoid fractures had significant osteoporosis at the dens-body junction. Five patients with Type II fracture and eight patients with no Type II fractures had significant osteoporosis at the dens and body of axis. Statistical analysis showed that the osteoporosis at the dens-body junction was not significant in patients with Type II odontoid fracture compared to those with no Type II odontoid fracture (χ² = 1.1; df = 3, p = 0.78).

Conclusions: Eventhough osteoporosis is one of the factors that increase the incidence of Type II fractures of the odontoid process in the elderly, it is not a direct aetiological factor.

Introduction Polyethylene wear debris is an important cause of failure in cemented total hip arthroplasty. As a result of the biological response to debris at the bone-cement interface, osteolysis and subsequent failure occurs in both femoral and acetabular components. Most acetabular components and liners are made of ultra high molecular weight polyethylene (UHMWPE). Cross-linking UHMWPE has been shown to significantly reduce abrasive wear in hip simulator studies. The wear rates measured in vitro do not always correlate with the wear rates measured in clinical studies[1]. Some new polyethylenes have shown catastrophic wear in clinical studies despite encouraging hip simulator study results[2]. The aim of this study was to compare the wear of standard UHMWPE to that of cross-linked UHMWPE (Longevity, Zimmer, Warsaw, USA)

Patients and Methods This was a prospective, double blind, randomised control trial. 50 subjects were recruited, all of whom received the cemented CPT stem and uncemented Trilogy liner (Zimmer, UK). Subjects were randomised to receive either a standard Trilogy liner or a Longevity liner at the time of operation. Both liners are identical in appearance. All liners were of a neutral configuration. RSA was used to measure linear wear. This was calculated by measuring the distance between the centre of the femoral head and the centre of the acetabular liner. The preliminary results of the study are presented.

Results Both groups underwent significant wear over two years. The two year linear wear of the cross-linked UHMWPE was 0.3mm (+/− 0.06mm, p< 0.001). The two year linear wear of the standard UHMWPE was 0.39mm (+/− 0.04mm, p< 0.001). No significant difference existed between the two groups (p=0.24). Both cohorts had around 0.15 to 0.2 mm of measured wear per year. Cross-linked UHMWPE therefore underwent less wear than standard UHMWPE at two years, however this difference was not statistically significant.

Discussion This study suggests that Longevity UHMWPE has similar wear properties to standard UHMWPE in the first two years following implantation. This does not correlate with in vitro hip simulator studies of Longevity polyethylene, which show a significantly lower wear rate than standard UHMWPE. It suggests that hip simulator studies may be of little value in predicting in vivo wear rates and that all new types of polyethylene should be evaluated clinically and radiologically prior to general release. Whether both cohorts continue to wear at similar rates will only be revealed through continued observation.

Introduction. Leg length inequality post total hip arthroplasty is a source of patient dissatisfaction. In adult DDH femoral length equality is assumed. Empirically, a longer femur has been observed on the affected side in the presence of unilateral DDH; restoration of the hip centre in this situation may lengthen the affected leg.

Aim. Assessment of femoral length variation in adults with unilateral and bilateral DDH.

Method. Retrospective observation study of 17 adults with unilateral and 7 adults with bilateral DDH. Femoral lengths assessed using CT measurements.

Results. Unilateral DDH. The ipsilateral femur was longer in 11 patients (63%) The degree of femoral lengthening was between 5 and 10 mm. Bilateral DDH. The femur with the greater degree of DDH was longer by a mean of 7.5 19.3 mm .

Conclusion. In the presence of DDH, asymmetry of femoral lengths is common and unpredictable. Careful femoral length assessment ( with CT leg lengths) is advised preoperatively in patients with DDH. This will alert the surgeon and patient to the possible risk of post operative ipsilateral leg lengthening.

Aim: To report our experience and early results with flexible nailing for unstable or irreducible displaced proximal humeral fractures in children.

Material & methods: Between 1997 & 2004, 15 children with unstable or irreducible displaced fractures of the proximal humerus were treated with closed/open reduction and flexible IM nailing. There were 10 boys and 5 girls. The median age of the patients was 12.5 years (9–15). Thirteen children had a Salter – Harris II, Neer grade III/IV fracture and 2 children had metaphyseal fractures. The outcome assessment was performed using the shoulder score, clinical and radiological parameters.

Results: All fractures united. None of the patients had a clinically significant malunion/shortening. Three patients had irritation at the nail insertion site. One patient had a transient radial nerve neurapraxia. There were no other operative or postoperative complications. The flexible nails were removed at a median time of 6 months (1.5–10) in 12 patients and 3 patients are awaiting removal. At a median follow-up of 30 months (4–66) all patients had a normal or near normal glenohumeral motion, full strength and all reported regaining full pre-injury functional use of the involved extremity.

Conclusion: Flexible nailing can be used safely to maintain reduction in unstable or irreducible displaced fractures of the proximal humerus and allows early return to normal activities and function with minimal complications. This treatment is also useful in older children who have minimal remodelling potential.

Background: Type II odontoid fractures are the commonest upper cervical spine injury in the elderly, following minor falls. Structural heterogeneity within the axis with deficiency of bone mass in the base of the odontoid process has been attributed for these fractures.

Aims: To analyse whether osteoporosis at the dens-body junction is directly related to the occurrence of odontoid fractures in the elderly.

Material and Methods: We studied the reformatted CT scan images of 36 patients over the age of 70 years who had cervical spine injuries following minor trauma. In all these patients the severity of osteoporosis at the dens-body junction, and in the peg and body of axis were evaluated. The severity was graded into none, mild, moderate and severe, depending on the cortical thickness, trabecular pattern, and the size of holes (absence of trabeculae) using sagittal, coronal and transverse sections of CT scan pictures. The osteoporosis was graded into none, mild, moderate and severe. Statistical analysis was performed using Pearsons Chi-square test to find the significance of osteoporosis at the dens-body junction in producing Type II odontoid fractures in the elderly.

Results: Type II odontoid fractures was seen in 21 patients. Eleven of the 21 patients with Type II fractures and eight of the 15 patients with no Type II odontoid fractures had significant osteoporosis at the dens-body junction. Five patients with Type II fracture and eight patients with no Type II fractures had significant osteoporosis at the dens and body of axis. Statistical analysis showed that the osteoporosis at the dens-body junction was not significant in patients with Type II odontoid fracture compared to those with no Type II odontoid fracture (Chi-square value = 1.1; df = 3, p = 0.78).

Conclusions: Eventhough osteoporosis is one of the factors that increase the incidence of Type II fractures of the odontoid process in the elderly, it is not a direct aetiological factor.

Arthroscopic procedures may be associated with considerable pain in the first 24 hours. Intra-articular bupi-vacaine provides good analgesia but is short lasting. Intra-articular morphine has been shown to prolong postoperative analgesia in knee and ankle arthroscopy. The aim of this study is to assess the safety and analgesic effect of intra-articular morphine following day case wrist arthroscopy.

Ethical approval was firstly obtained. 31 patients were randomly assigned to one of 2 groups in a double blind clinical study. Group 1 received 5ml of 0.5% bupi-vacaine intra-articularly with 5mg of morphine subcutaneously. Group 2 received 5ml of 0.5% bupivacaine and 5mg of morphine intra-articularly. There were 15 patients (mean age 41.2 years) in group 1, and 16 patients (mean age 38.9 years) in group 2. Postoperatively pain was assessed using a 100mm visual analogue pain scale (VAPS) at 1, 2, 6 and 24 hours. Analgesia requirements were recorded at these times post operatively. The presence of nausea, vomiting, other complications and patient satisfaction were recorded.

Visual analogue pain scores did not show any significant difference between the groups at 1, 2, 6 and 24 hours. Supplementary analgesic consumption over the 24 hour period was slightly greater in group 1 than in group 2. None of the patients who had intra-articular Morphine had vomiting nor any other complications and did not require anti-emetics. Most patients in either group were satisfied with the level of postoperative analgesia.

Intra-articular bupivacaine with or with out morphine provides adequate postoperative pain relief following wrist arthroscopy. There seems to be little difference between the two methods studied.

Purpose: Congenital proximal radioulnar synostosis is a rare anomaly of failure of segmentation of the radius and ulna resulting in a fixed rotational position of the forearm from neutral to maximum pronation. Several surgical options have been proposed for the treatment of this condition. We have treated six forearms in five children with pronation deformity using derotational osteotomies of the radius and ulna with postoperative wire stabilisation of the ulna. The surgical technique and results of treatment with this method are presented.

Methods: With this technique, osteotomies were performed at the midshaft of the ulna and the distal diaph-yseal-metaphyseal junction of the radius. The insertion of intramedullary Ilizarov wires facilitated manual derotation of the radius and ulna to a functional position of 100 supination of the forearm. Postoperatively, the forearm was immobilised in a cast for an average of 6.3 weeks and the wire was removed when there was evidence of union. 3 boys and 2 girls with a mean age of 4.9 years underwent surgery with this method and were followed-up for an average of 29 months (range 12 to 43 months).

Results: Forearm position improved from an average pronation deformity of 68.3 degrees to the pre-planned position of 100 degrees supination in all cases. Bone union was achieved in all six forearms by 6.3 weeks. At their most recent follow-up, there was no loss of correction evident in any of the patients. There was one complication, namely haematoma formation at the radial osteotomy site mimicking compartment syndrome and requiring exploration, although no soft tissue compromise was evident.

Conclusion: The principal advantages of this technique include the ease of the surgical approach for the distal radial osteotomy, the longterm maintenance of rotational correction and the need for single wire stabilisation of the ulna only, which in theory reduces the potential risk of implant-related complications. We conclude that this modified forearm derotational osteotomy with wire stabilisation of the ulna alone is a safe and effective method for treating pronation deformity in children with congenital proximal radioulnar synostosis, although vigilance for early soft tissue complications is necessary.

Background: The most commonly used implant for the internal fixation of an extracapsular proximal femoral fracture is a sliding hip screw (SHS). More recently short intramedullary nails (IMN) have been advocated as an alternative, particularly for unstable fractures due to possible biomechanical advantages. The purpose of this meta-analysis was to compare, on the basis of evidence from randomised controlled trials, the fixation outcome with these two types of implant in stable and unstable fractures

Method: All randomised controlled studies comparing intramedullary nails with a SHS were considered for inclusion. Studies were identified using the search strategy of the Cochrane Collaboration, with no restriction on languages or source. Two authors independently extracted the data, and assessed trial methodology.

Results: 24 randomised trials involving 3202 patients with 3279 fractures were included in the analysis. Pooled results gave no statistically significant difference in the cut-out rate between the IMN or SHS 41/1556 and 37/1626 (Relative risk 1.19; 95% confidence interval 0.78 to 1.82). There was an increased total failure rate (103/1495 and 58/1565, Relative risk 1.83; 95% confidence interval 1.35 to 2.50) and re-operation rate (57/1357 and 35/1415, Relative risk 1.63; 95% confidence interval 1.11 to 2.40) with the IMN compared the SHS when all fractures were considered. Fracture healing complications were much less frequent for stable fractures. No evidence for a reduced failure rate for IMN’s in unstable fractures patterns could be found.

Conclusions: The results from studies to date indicate an increased fixation failure rate for trochanteric fractures fixed with an intramedullary nail, and show no benefit to the use of a nail in unstable fractures. Therefore the use of intramedullary nails for trochanteric fractures cannot be recommended.

Normal acetabular development in developmental dysplasia of the hip (DDH) depends upon early and maintained congruent reduction. Computed tomography is an accepted method for evaluating this and attempts to quantify hip reduction, by various angular and linear measurements, have been reported.

The aim of this study was to assess initial CT scans, following open reduction in the older child with DDH, with comparison of outcome to evaluate prognostic value.

Method: Thirty consecutive patients underwent open reduction for DDH, with a mean age of 25.9 months at the time of operation. Acetabular morphology and the position of the femoral head were evaluated on the initial CT scan, taken on the first postoperative day, and AP pelvic radiograph taken at the latest follow-up.

Results: The acetabulae of the dislocated hips were found to be significantly more anteverted than the normal. The dislocated hips also had significantly increased lateral displacement both initially and at latest follow-up. Posterior displacement of the proximal femoral metaphysis should raise concern due to an association with the need for further surgical intervention. These results did not however correlate with outcome.

In conclusion, despite the significant differences noted between DDH and normal hips they did not predict acetabular development or persistent acetabular dysplasia.

Introduction: The Charnley Elite femoral component was first introduced in 1992 as a new design variant of the original Charnley femoral component (De Puy, Leeds, UK) with modified neck and stem geometry. The original component had undergone few changes in nearly forty years and has excellent long-term results.

Early migration of the new stem design was determined by Roentgen Stereophotogrammetric Analysis (RSA). Rapid early migration of a component relative to the bone, measured by RSA, is predictive of subsequent aseptic loosening for a number of femoral stems. As there was rapid early migration and rotation of the Charnley Elite stem, we predicted that the long-term results would be poor. An outcome assessment is required as stems of this type are still being implanted.

Materials and method: One hundred Charnley Elite stems, implanted in our centre between 1994 and 1997 were included in a prospective, cross-sectional follow-up study. Outcome measures include validated clinical scores (Charnley hip score, Harris hip score and Oxford hip score) and radiological scores (Gruen classification) as well as revision rates over the past 10 years.

Results: The preliminary analysis results are given. The mean time to follow-up was 8.28 years. 20 patients have died due to causes unrelated to their operations. 10 patients had stem revisions: 9 for aseptic loosening and 1 for a peri-prosthetic fracture. This indicates a significant 10% failure rate of the prosthesis in less than 10 years.

Preliminary clinical scores in the patients who had not undergone any subsequent surgery were adequate (Oxford Hip Score mean average of 23.9).

Thirteen percent of radiographs analysed had evidence of loosening, giving an overall loosening rate of 14% at 8 years.

Discussion and conclusion: The clinical follow-up supports the RSA predictions of early failure of the Charnley Elite femoral stem.

Introduction: Current evidence suggests that CES should be operated within 48 hours from onset of sphincteric symptoms in order to maximise chances of recovery. Measurement reproducibility of large disc prolapses and clinical correlations have not previously been studied.

Objectives: (1) Determine whether initial MRI findings correlate with clinical outcome (2) Study the reproducibility of MRI measurements of large disc prolapses (3) Estimate the ability to predict CES based on MRI alone.

Study Design: 31 patients with CES were identified, the case notes reviewed and the patients invited to attend clinic. Outcome consisted of history and examination, and several validated questionnaire assessments. 19 patients who underwent discectomy for persistent radiculopathy were identified. None had sphincteric symptoms. All had a significant surgical target. Digital photographs of all 50 MRIs were obtained showing the T2 mid-sagittal image and the axial image with the greatest disc protrusion. The Observers: 1 Consultant Radiologist, 2 Consultant Spinal Surgeons and 1 SHO did not know the number of patients in each group. Observers estimated the percentage spinal canal compromise on each view and indicated whether they thought the scan findings could produce CES. Measurements were repeated after 2 weeks.

Results: 26 patients attended clinic mean follow up 51 months (25 to 97). As expected, the % canal compromise differed significantly between the two groups (p0.001). 12 of the 26 patients with CES had, on average, over75% canal compromise. No significant correlations were found between MRI canal compromise and clinical outcome. Canal compromise did predict whether the patient would fail their Trial Without Catheter (p0.05). Based on MRI alone, the correct identification of CES has sensitivity 68%, specificity 78%, positive predictive value 84% and negative predictive value 58%. Kappa values for intra-observer reproducibility ranged from 0.4 to 0.85 for sagittal compromise, axial compromise and correct prediction of CES. All three interobserver kappa values for these measurements were 0.64.

Conclusions: This is the largest radiological case series of CES with 4 years clinical follow up. Canal compromise on MRI does not appear to directly predict clinical outcome. Reproducibility of MRI measurements of large disc protrusions has substantial agreement. MRI could be of help in equivocal cases if the scan shows a large disc.

We propose a grading system for contrast free MRI images of tennis elbow and evaluate the inter and intra observer variability of their interpretation.

Methods: Three senior orthopaedic surgeons were asked to blindly grade 0.2T dedicated extremity contrast free MRI images of elbows of patients who presented with varying degrees of symptomatic tennis elbow.

Our proposed grading system of 1 to 5 based on the pattern around the common extensor tendon was used.

Images of the symptomatic and contralateral non symptomatic elbows were graded blindly twice with an interval of 1 month by each surgeon.

Each surgeon graded 176 MRI images twice.

The grades were subsequently grouped into (I) grades 1 to 2 and (II) grades 3 to 5

Results: With regards to the intra observer agreement, consultant A showed 90.1% agreement, consultant B showed 90.6% agreement and consultant C 96.0% agreement. The mean intra observer agreement rate was 92.2%.

The inter observer agreement between consultant A and B was 82.46%, between A and C 67.1% and between B and C 80.1%.

It was also noted that there were systematic differences to the inter observer variability. Consultant A graded the images 3 to 5 on both occasions 52.9% of the time, consultant B graded 3 to 5 on both occasions 37.8% of the time and consultant C graded 3 to 5 on both occasions 23.3% of the time.

Conclusion: The intra observer agreement rate is high. There is however a greater inter observer variation but this variation is consistent. We suggest that the inter observer differences can be improved by (1) reducing the grades to positive or negative and (2) by group reeducation of the observers.

Surgical treatment of complex deformities necessitates a detailed appreciation of the complex three dimensional abnormal anatomies involved. Preoperative planning for these complex cases traditionally involves x-ray and computerised tomography (CT). These modalities offer only two-dimensional images to represent three-dimensional anatomy. Advances in digital imaging have allowed three-dimensional reconstructions to be derived from CT images. These greatly improve understanding of complex deformities, but will never be able to replace the intuitive understanding that is gained by handling a physical model.

The Rapid Prototyping technique Selective Laser Sintering (SLS) is used in the industrial setting to manufacture prototype models from Computer Aided Designs (CAD). This technology can be utilised to convert CT images into accurate three-dimensional physical models of the human bony anatomy.

We present the use of SLS modelling to aid in the preoperative planning of complex reconstructive surgery in children. Cases include bladder exstrophy, developmental dysplasia of the hip and reconstruction of a complex elbow malunion.

The models provide invaluable visual and tactile information to the operating surgeon, accurately demonstrating the abnormal anatomy in an easily comprehensible manner. They allow estimation of the magnitude and degree of corrections necessary and evaluation of bony deficiencies.

Aim and method We report the outcomes of 100 consecutive diabetic patients who had been prescribed diabetic footwear for 10 years. A podiatrist and orthotist reviewed them at a dedicated clinic. The study aim was to assess footwear efficacy and prevention of ulcers, re-ulceration and amputations.

Conclusion Protective footwear is essential in maintaining healthy diabetic feet. Amputations were only due to vascular complications. All 56 patients who attended remained intact at 2 years. Of the seven ulcerations at 5 years, three went onto below-knee amputation. At 10 years, there were a further three ulcerations, resulting in one minor black toe and one further BK amputation.

Adherence with follow up including footwear review minimises risk. Re-ulceration at 5 years is associated with risk of amputation. Ten-year mortality is high due to vascular complications.

Summary Continued patient adherence with Orthotic therapy confers benefit and minimised re-ulceration. Follow up by Orthotists is an under-utilised resource.

Introduction and Aims: Autologous chondrocyte implantation (ACI) is emerging as a leading technique for the treatment of articular cartilage defects. However, there exists some debate regarding which ACI technique is best able to regenerate hyaline cartilage. To this end, the development of a non-invasive technique enabling the examination of microstructure after ACI is essential.

Method: In this study, we have developed a novel 2D Laser Scanning Confocal Arthroscope (LSCA) in the assessment of articular cartilage and examined the microstructure of knee articular cartilage from rabbits and patients with total knee arthroplasty. The LSCA system consists of the LSA handheld probe, a Launch and Detection Unit (LDU) with a built in 488nm–514nm Krypton Argon Laser and Master Control unit (MCU). Human and rabbit knee articular cartilage stained with Fluoroscein (5g/L) and Acriflavine (0.5g/L) were used to examine the microstructure of cartilage by LSCA.

Results: By LSCA we have generated optical histology images of normal human and rabbit articular cartilage from the femoral condyle. Optical histology of normal articular cartilage tissue reveals typically smooth surface texture with relatively homogenous sub-surface distribution of viable chondrocyte cells. The general orientation of collagen fibres is occasionally visible in surface images. Optical histology of arthritic cartilage of humans showed clusters of round-shaped chondrocytes mixed with spindle-shaped cells. Surface cracking typically indicative of tissue damage is also evident by LSCA observation. Examination of rabbit knee six weeks after ACI showed high density of chondrocytes and homogeneous matrix on the site of the defect.

Conclusion: In short, we have shown the efficacy of LSCA in the non-destructive assessment of articular cartilage in vivo. Further study is required to evaluate the clinical significance of optical histology of LSCA.

Introduction and Aims: To determine whether sagittal laxity has an effect on functional outcome following posterior cruciate retaining total knee replacement using two differing tibial insert designs.

Method: Ninety-seven knees in 83 patients were reviewed clinically, radiologically and underwent KT1000 testing at minimum five-year follow-up post-TKA. Knee society, WOMAC and SF12 scores were calculated. The same femoral component (Duracon, Stryker) was used in all patients. Two differing tibial inserts were used (51 Condylar and 46 AP lipped).

Results: The two groups were comparable for age, sex, Charnley category and Body mass index. There was no significant difference in knee society score, WOMAC scores, SF12 scores, knee flexion, posterior tibial slope or KT1000 laxity measurements between the two groups. Total laxity measured by KT1000 was 5mm in the AP lipped group and 4mm in the condylar group. There was no correlation between anterior, posterior or total laxity and functional outcome as measured by WOMAC, KSS, SF12 or knee flexion.

Conclusion: Increased sagittal laxity does not have a strong influence on functional outcome following TKA. The differing tibial insert designs had no significant influence on laxity or function.

Study Design: Retrospective Series.

Objectives: To analyse loss of correction of the anterior wedge angle and the components responsible for the recurrence of kyphosis after surgical stabilisation of dorsolumbar fractures, and to assess the return of functional capacity in these patients.

Materials and Methods: Between January 1998 and March 2003, 34 patients had posterior stabilisation performed with the Universal Spine System (Synthes) for dorsolumbar fracture at a single level with no neurological deficit. There were 26 AO Type A fractures, 5 Type B fractures, and 3 Type C fractures. Serial standing lateral radiographs were taken from the immediate postoperative period to the most recent follow-up. The anterior wedge angle, the heights of the discs above and below the fractured vertebra, and the heights of the vertebral bodies above, at, and below the fractured level were measured. The height at each level was measured in three segments (anterior, middle and posterior). The values were normalised to avoid discrepancies while comparing radiographs. The difference in the height of each segment measured between the immediate postoperative period and the most recent follow-up were computed. Short Form 36 (SF-36) was used to assess the functional outcome in each.

Results: The mean follow-up period was 23.6 months (9 to 48 months). The mean anterior wedge angle was 10.1 ± 7.2 degrees in the immediate postoperative period and 17.1 ± 10.9 degrees at latest follow-up (p< 0.001). The mean loss of correction was 7.0 ± 8.5 degrees (−11 to 24) and this showed a linear relationship to the preoperative anterior wedge angle. Furthermore there was a linear increase in the loss of correction of the angle as the follow-up period increased. The correlation between the corresponding difference in the height of each segment and the degree of loss of correction of the anterior wedge angle showed significant correlation to the decrease in the anterior segment height at the fractured vertebral body level (Pearson’s coefficient r=0.53 significant at 0.01 level, p=0.001). The mean physical function score from SF-36 was 56.3 and the mean bodily pain score was 49.7. There was no relationship to the angle of kyphosis at follow-up to the physical function score (r=0.12, p=0.50) and the bodily pain score (r=0.14, p=0.44).

Conclusions: There is a progressive loss of correction (increasing kyphosis) after posterior stabilisation with instrumentation that roughly approximates the initial decrease in anterior height of the fractured vertebral body. The degree of loss of correction does not depend on the type of fracture. The loss of correction is related to the preoperative angle of kyphosis.

Introduction: The Birmingham Hip Resurfacing (BHR) is a metal on metal prosthesis with no published independent clinical studies. It is increasingly used as an alternative to stemmed prostheses in younger patients.

This study presents the 2 year migration results of the BHR femoral component using Roentgen Stereophoto-grammteric Analysis (RSA).

Methods: 26 hips in 24 subjects underwent a BHR, through the postero-lateral approach using CMW3G cement. RSA marker balls were placed in the cortical bone of the femur intra-operatively. The femoral component migration was measured at intervals of 3, 6, 12 and 24 months postoperatively using the Oxford RSA system. The implants were un-modified, geometric algorithms were used to identify the femoral component.

Results: The BHR femoral component showed no significant displacement from its immediate post-operative position. All components of migration showed no significant displacement in any direction, at 1 or 2 years.

Conclusion: The BHR femoral component does not migrate significantly within the first two post-operative years. Its’ migration compares favourably to other designs of femoral component. The BHR is therefore likely to remain stable in the future, as the majority of implant migration occurs within the first two years.

Study Design: Retrospective review.

Objectives: Rugby union has recently become a highly-paid professional sport. Players requiring anterior cervical discectomy wish to know the effect this will have on their career. To answer this question, the result of the above procedure in professional rugby players was studied.

Methods: A retrospective notes review and telephone interview were conducted on 19 professional rugby players who had a cervical discectomy between 1998 and 2003. Pre and post operative symptoms and numbers returning to rugby after surgery were assessed.

Results: Neck pain was eradicated in eight (42%) of the players, nine (47%) achieved partial relief and two were not helped. Brachalgia was eradicated in fifteen (79%) individuals, improved in two (10.5%) and two (10.5%) had no relief. Fourteen (74%) returned to rugby union, the majority at six months post operatively (range – five to 17 months). Thirteen (68.5%) returned to their pre-operative level of rugby; one dropped to a lesser division and five have never played rugby again (three due to physical inability, one due to club reluctance to insure and one because of a separate injury). Two of the players that returned to rugby have subsequently retired because of neck symptoms. They played three and two years post-operatively at first-class level.

Conclusion: Return to rugby union after anterior cervical discectomy is both likely and safe and therefore need not be a career ending procedure.

Accurate and relevant patient chart notes are a key component in successful patient care. Hospital charts also constitute an important medicolegal record. The key to defensibility of at least 40% of medical claims rests with the quality of the medical records. With this in mind, we decided to assess the quality of chart note keeping in our unit. A retrospective review of fifty randomly chosen charts was performed. A scoring system was devised to audit ten key criteria comprising patient details, admission note, daily progress notes, signature clarity, consent form, operation note, post-operative plan, post-operative x-ray review, specification of right or left side and discharge letter. Members of the orthopaedic surgical staff were then informed of the chart review and the nature and purpose of the study was explained in detail. They were also told that there would be another chart audit at some random time over the following three months. Subsequently, a further fifty charts were assessed using the same criteria and scoring system. Overall, charts scored poorly in the areas of patient details, clarity of signatures, post-operative x-ray review and left-right specification. Criteria that scored satisfactorily included admission note, consent form, operation note, post-operative plan an discharge letter. Meticulous hospital notes are vitally important in the day-to-day management of patients for successful continuity of care and also for protection of the medical staff should any adverse outcomes arise. In this litigious society consultants and junior medical staff need to be reminded of the importance of optimal note keeping.

Aims: Surgical joint stabilisation can be achieved by capsular plication or thermal shrinkage. We hypothesised that there was no difference in mechanical and morphological properties after reduction of laxity in ligaments treated by either technique.

Methods: 30 skeletally mature female rabbits underwent either ‘thermal’ treatment, or ‘plication’ of their left medial collateral ligament (MCL). After 12 weeks convalescence, MCL complexes were procured from left and contralateral knees to undergo viscoelastic (creep) testing, quantitative transmission electron microscopy (TEM) and immunohistochemistry.

Results: Mean creep strain in both thermal (1.85 +/− 0.32%) and plicated ligaments (1.92 +/− 0.36%) was almost twice that of the control group (1.04 +/− 0.15%), although there was no difference between treatment modalities. However, collagen morphological parameters of all three groups were significantly different (p< 0.001). The thermal ligaments demonstrated predominantly small fibrils, whilst the plicated group displayed an intermediate distribution of heterogeneous fibrils (Fig. I). Immunohistochemistry followed by TEM revealed a random distribution of alpha-smooth muscle actin staining fibroblasts in both thermal and plicated groups.

Conclusion: Susceptibility to creep, and residual deformation after recovery, is similar after thermal shrinkage or plication, although inferior to intact ligaments. However, a different pattern of remodelling was revealed in the treatment groups. The plicated results suggest remodelling on a pre-existing fibrillar scaffold, yet the thermal group demonstrated histomorphometry similar to scar tissue, suggesting de novo synthesis. The absence of contractile myofibroblasts suggests that these cells may play an insignificant role in regulation of matrix tension during healing.

Study Design. A reliability study of the Modic classification.

Objective. To determine the reliability and reproducibility of the Modic classification for lumbar vertebral marrow changes.

Summary of Background data. In 1988, Modic with colleagues described two degenerative stages of vertebral marrow and endplate morphology. These were Type I (inflammatory phase) and Type II (fatty phase). Later in 1988, he added a third variety; Type III where there was marked sclerosis adjacent to the endplates. No formal reliability or reproducibility studies had been performed on the Modic classification.

Methods. This study involved five independent observers of differing spinal experience using the Modic classification to grade fifty sagittal T1 and T2 weighted MRI scans. The observers repeated the assessment at three weeks. Intra- and inter-observer reliabilities were assessed using kappa statistics.

Results. There were 7 type I, 40 type II, 1 type III and 2 normal levels. The individual intra-observer agreement was substantial or excellent with kappa values ranging from 0.71 to 1.00. The overall inter-observer agreement was excellent with a kappa value of 0.85. There was complete agreement in 78% of the levels, a difference of one type in 14% and a difference of two or more in 8% of levels. The level of experience of the observer did not correlate with a better score.

Conclusions. We have shown that the Modic classification is both reliable and reproducible. It is simple and easy to apply for observers of varying clinical experience. We therefore recommend its use in clinical research and practice.

Introduction and Aims: It has been suggested that elderly patients have poorer outcomes following carpal tunnel decompression than younger patients, especially if there is severe compression. The purpose of this study was to determine the outcomes of carpal tunnel decompression in the elderly patient and whether the outcome could be predicted from pre-operative nerve conduction studies.

Method: A retrospective study of all patients over 70 years who had a carpal tunnel release over a three-year period at Dunedin Hospital, with a minimum one-year follow-up. Pre-operative nerve conduction studies were graded from one to six according to severity. Patients were followed up by postal questionnaire (Boston carpal tunnel symptom severity score) and telephone follow-up.

Results: 109 procedures were performed in 96 patients. Eight patients had died, two excluded (one with Motor Neurone disease and one acute CTS following fracture) and five were demented and unable to fill out the questionnaire. Eighty-one patients with 92 wrists were available for review. Mean age was 78.6 years. Eighty percent had marked to severe neurophysiological changes (Grade 4–6). Post-operatively, the median Boston score was 1.27 with 84% having a Boston score of < 2.0. Patients were satisfied with the result in 94.6% of procedures. There was a positive correlation between nerve conduction grade and post-operative Boston Score (p=0.042).

Conclusion: Despite nerve conduction studies consistent with marked to severe compression, elderly patients have low symptom severity scores following carpal tunnel decompression and a high rate of satisfaction. Carpal tunnel release in patients over 70 years of age is justified and usually associated with a good outcome.

Introduction and Aims: Conventional histology requires the traumatic removal of tissue from its native environment. This is not only a destructive process but also leads to tissue preparation artefact. We report on a novel arthroscopic instrument, the laser scanning confocal arthroscope (LSCA), which can image tissues of the knee at depth without the need for a damaging tissue biopsy.

Method: The new confocal arthroscope contains 4.4mm diameter with a 90-degree lens. Using three knee joints from two adult Merino sheep we imaged muscle, cartilage, ligament, tendon, synovium, meniscus and loose connective tissue. The knees were separately injected with three fluorophores (Acridine Orange, Acriflavine/Calcein-AM or Fluorescein) prior to imaging. Using a medial para-patellar incision, the contents of the knee were exposed and the confocal arthroscope was held directly on the tissue of interest. A second operator captured the images on a computer.

Results: We were able to demonstrate the common histological features of normal sheep articular cartilage, meniscus, synovium, ligament, tendon and muscle. Tissues were imaged to depths of 200 microns. Articular cartilage was characterised by a layer of dense superficial cells surrounded by extracellular matrix. There was no visible orderly arrangement of cells in this layer. Meniscus was characterised by closely packed circumferential collagen fibres. Synovium demonstrated a dense collection of cells in a thin membrane, typical of this secretory tissue. Ligament and tendon were characterised by bundles of parallel collagen fibres interspersed by scattered cells. Muscle revealed a typical arrangement of muscle fibres surrounded by a loose connective tissue and separated by capillaries and nerves. Eccentric nuclei were seen, however striations were beyond the imaging resolution of the arthroscope.

Conclusion: This study demonstrates the use of a novel arthroscopic instrument for the non-destructive examination of the components of the sheep knee joint. We foresee that the laser scanning confocal arthroscope will have future application in the assessment of cartilage grafting techniques and arthritis modifying drugs.

Introduction and Aims: Odontoid fractures are quite common in the elderly following minor falls. As there are a few articulations in the upper cervical spine, degeneration in any one particular joint may affect the biomechanics of loading of the upper cervical spine. We aimed to analyse the pattern and relationship of odontoid fractures to the upper cervical spine osteoarthritis in the elderly.

Method: Between July 1999 and March 2003, 185 patients had CT scan of the cervical spine for cervical spine injuries. Twenty-three out of 47 patients over the age of 70 years had odontoid fractures. The CT scan pictures of these patients were studied to analyse the type of fracture and its displacement, the severity of osteoarthritis in each articulation in the upper cervical spine, namely lateral atlantoaxial, atlantooccipital, atlantoodontoid and subaxial facetal joints, evaluation of osteopenia in the dens-body junction and in the body and odontoid process of the axis, and calcification of the ligaments.

Results: Twenty-one of the 23 patients had Type II odontoid fracture with posterior displacement in seven (33.3%) and posterior angulation in nine (42.8%) patients. In these patients with Type II dens fracture, the atlantodens interval was obliterated in 19 (90.48%) patients, with only two of them (9.52%) having lateral atlantoaxial osteoarthritis.

Conclusion: Type II fracture is the commonest odontoid fracture in the elderly. Posterior displacement of the fracture is common in elderly, unlike the younger population. There is a significant relationship between the upper cervical spine osteoarthritis, apart from osteopenia, to the incidence of Type II odontoid fractures. Significant atlantoodontoid osteoarthritis in the presence of normal lateral atlantoaxial joints increases the risk of sustaining Type II odontoid fracture.

Intro: Quadriceps rupture following total knee arthroplasty is a devastating injury. Early operative repair is necessary to maintain the integrity of the extensor. Postoperative rehabilitation usually involves a prolonged period of immobilisation to allow the repair to consolidate. This immobilisation can cause irreversible stiffness in the patient with a total knee replacement. We present a method of rehabilitation to allow early range of motion.

Case Report: A 57 year old gentleman presented with bilateral tri-compartmental osteoarthritis, he had no other significant medical history. Bilateral synchronous total knee replacements were performed and the early post operative was unremarkable.

The patient fell whilst mobilising indoors at home during the fifth post operative week and sustained rapid hyperflexion injures to both knees. Ultrasound scans of the knees demonstrated bilateral discontinuities of the quadriceps mechanisms and a large fluid collection filling the defect.

The patient returned to the operating where a direct repair was achieved. Post operatively the patient was rested in bilateral cylinder casts until the sutures were removed at two weeks. For two week periods the knees were then mobilised in a hinged cast brace allowing 0–30, 0–60 and 0–90 degrees making the total time in cast 8 weeks

At the time of removal of the casts the patient had 110 degrees of flexion in the right leg and 85 degrees of flexion in the left. At six months postoperatively the patient flexes freely to over 100 degrees

Conclusion: Bilateral quadriceps ruptures in a relatively young patient can be managed with early repair and an aggressive rehabilitation regime. This case suggests that is possible to achieve a satisfactory outcome although the input required is significant.

Introduction: Current evidence suggests CES should be operated < 48 hours from onset. MRI scanning is often not available 24 hours a day.

Objectives: (1) Determine whether MRI findings correlate with clinical outcome. (2) Study the reproducibility of MRI measurements of large disc prolapses. (3) Estimate the ability to predict CES based on MRI alone.

Study Design: 31 CES patients were identified,contactedand invited to follow up. Clinical outcome consisted of history and examination, and validated questionnaire assessments. 19 patients who underwent discectomy were identified. T2 mid-sagittal and axial digital photographs of all 50 MRIs were obtained. Observers did not know the number of patients in each group (1 Consultant Radiologist, 2 Consultant Spinal Surgeons and 1 SHO). They estimated the percentage spinal canal compromise on each view (0–100%) and indicated whether they thought the scan findings could produce CES. Measurements were repeated after 2 weeks.

Results: 26 patients attended clinic (mean follow up 51 months). There were no significant correlations found between MRI canal compromise and clinical outcome. Kappa values for the measurements ranged 0.52–0.85 and 0.61–0.75 for intra- and inter-observer reproducibility. Based on MRI alone correct identification of CES has sensitivity 67%, specificity 81%, positive predictive value 85% and negative predictive value 60%.

Conclusions: Canal compromise on MRI does not predict the outcome of patients with CES. Reproducibility of MRI measurements of large disc protrusions has substantial agreement. MRI could be of help in equivocal cases if the scan shows a large disc.

Purpose of Study: To determine whether preprocedure psychological assessment can be used to predict the outcome following intradiscal electrothermal therapy (IDET).

Materials and Methods: Patients undergoing IDET at our unit between April 2000 and March 2002 were asked to complete a pain diagram and a Short Form 36 (SF36) (UK Version 1). Patients were followed up after IDET by means of a postal questionnaire. Patients outcome was assessed using a visual analogue pain score (VAS), an SF36 and a subjective outcome assessment. Pain drawings were classified as organic and non-organic according to the principle described by Mann et al.

Results: Forty-six (80.7%) patients were successfully followed up. Mean age was 41.2 years (range 16–76), 27 were female and 19 male. 73.9% of the pain diagrams were classified as organic and 26.1% as non-organic. The pain diagram was a good predictive tool for outcome following IDET. Patients with ‘organic’ pain drawings showed an improvement in mean pain VAS (pre 6.7, post 5.9), high patient satisfaction (Better 67.6%, Same 11.8%, Worse 20.6%), and higher physical component scores of the SF36 (Physical 64.1, Physical Role 45.6, Pain 54.0) compared to the ‘non-organic’ group who demonstrated a deterioration in mean pain VAS (pre 6.5, post 8.2), low patient satisfaction (Better 8.3%, Same 58.3%, Worse 33.3%), and lower physical component scores of the SF36 (Phsical 38.3, Physical Role 20.8, Pain 26.5).

Conclusions: Several authors have shown that certain preoperative psychological characteristics are associated with a poor outcome from spinal surgery. Some authors have demonstrated a correlation between these characteristics and pain diagrams when they are judged as ‘organic’ and ‘non-organic’. Our findings suggest that preprocedure psychological assessment is useful in predicting which patients will have a favourable outcome from IDET.

Pain drawings are quick and easy for patients to complete. Our study demonstrates pain drawings can reliably be used to predict outcome following intradiscal electrothermal therapy.

Background. Just under 2% of the joint infection work performed over the last 10 years in our institution has involved organisms found in the oropharynx. The issue of antibiotic prophylaxis for dental work in the presence of a joint prosthesis is controversial. However, advanced dental sepsis requires detection and treatment prior to joint replacement.

Methods. Patients from whom non B-haemolytic streptococcal were recovered from revisions of prosthetic joints over the period 1993–2003 were retrospectively reviewed for predisposing factors.

Results. 9 patients had viridans streptococcal infection detected and confirmed by histology and culture at excision arthroplasty. There were 5 total hip joints, 3 knee arthroplasties and 1 shoulder affected. No patient had a history of endocarditis. Two of the patients had previously had multiple revisions. Mean interval in these patients since last surgery was 7.6 years. All patients underwent 2 stage revision procedures. All patients required multiple dental extractions in the interval between 1st and 2nd stage surgery.

On reviewing the patients’ histories further: One patient had reported a broken tooth reported at the time of surgery and been given reassurancethat it was safe to proceed. One patient had an overt dental abscess ongoing for 15 years and one patient had an occult dental abscess revealed on radiology. Two other patients had extensive dental caries with blackened stumps as teeth. Follow-up after antibiotic treatment and revision arthroplasty is limited in these cases but results appear satisfactory at up to five years.

Conclusion. Poor dental care is associated with an increased risk of arthroplasty infection. Looking in the mouth should be a routine part of pre-op assessment prior to primary joint replacement, just as it would be in a cardiac surgery unit. Patients referred from other centres for revision arthroplasty should receive a dental examination if excision arthroplasty cultures yield viridans streptococci.

We report early major complications encountered following TEN fixation of femoral fractures in children.

A case series of four children aged 8– 16 years who had primary TEN fixation of isolated femoral diaphyseal fractures.

Three of the four patients had major complications. These were: significant knee stiffness requiring manipulation, haemarthrosis requiring washout and nail removal, loss of position and refracture. Two required revision to locked intramedullary nails without early complication.

In the skeletally immature child TEN fixation of femoral fractures has a significant major complication rate. This needs to be recognised when comparing TEN fixation with other treatment options.

Aim: To review the early complications associated with staged revision hip Arthroplasty utilising the Biomet antibiotic loaded cement spacer.

Method: We report on 80 consecutive staged revision hip replacements using the Biomet antibiotic loaded cement system in our institution over 3 years (1999–2002), performed by three consultant surgeons, with a minimum 1 year follow up.

Results: Our patients had an average age of 68 (range 48–90) years, with an equal sex distribution.

The median time between the first and second stage was 147 (range 50–619) days.

Fractures of the Biomet antibiotic loaded acrylic spacer occurred in 11% revisions when associated with an increase in time between stages and there was a 7% dislocation rate.

Patients did not receive a revision prosthesis in 19% cases and had early recurrent sepsis following their two stage procedure in 6%. Three patients had a single episode of dislocation of their revision hip prosthesis within a month postoperatively. Two patients had a proximal DVT and one patient had a pulmonary embolus. The mortality within eight weeks was 7%, rising to 10% within a year. This may be related to patient sepsis and comorbidities or the energy expenditure required to mobilise following a first stage procedure that we have analysed.

Conclusions: The risks of staged revision hip surgery for infection are substantial when considering the time involved, the energy expenditure required to mobilise following a first stage, the possibility of not achieving a revision hip prosthesis and the mortality rate.

The Biomet antibiotic loaded cement system articulates and maintains soft tissue length in the majority of patients for the duration required between stages.

We report intermediate term results of a technique of acetabular augmentation using block femoral head autograft and the uncemented expansion cup for adult hip dysplasia.

A retrospective review of one surgeon (BFH) series of consecutive total hip replacements for hip dysplasia using femoral head acetabular augmentation was carried out. The technique involves sectioning the femoral head longitudinally reversing and fixing it to the deficient acetabulum with 6.5mm AO screws. This is then reamed to accept the uncemented expansion cup. Patients were identified from audit databases. Patients completed clinical questionnaires, examination and radiographic evaluation.

Fifteen hips were identified in twelve patients (three bilateral). The average at age at surgery was 54 (44–58) years. There were eight females (eleven hips). Three patients (three hips) were unable to be contacted. Average follow up was 8.4 (4.8–11.4) years. Preoperative centre edge angle was 14 (−10–30) degrees. One patient developed a deep infection requiring early staged revision. One patient was not satisfied with her results at follow up. Mean Harris Hip Score was 83 (63–100), mean WOMAC Score was 76 (50–95). Range of motion was well maintained in all patients. Four patients had other co-morbidities affecting their results. Radiological review shows all grafts to have united with no screw breakage and no cup loosening.

At eight year follow up there is high satisfaction, good clinical and radiological results. These results demonstrate good intermediate term results using this technique in total hip replacement with acetabular dysplasia.

The aim of this study was to determine the outcome of carpal tunnel decompression in elderly patients and whether this can be predicted by the severity of pre-operative nerve conduction studies.

A retrospective study was undertaken of all patients over 70 years who had carpal tunnel release (CTR) at Dunedin Hospital between April 1999 and April 2002 with a minimum one year follow up. A grading system for pre-operative nerve conduction studies (NCS) was formulated which scored patients from 1 to 6 according to severity. Patients were followed up by postal questionnaire (Boston Carpal Tunnel Score) with telephone follow up of non-responders.

There were 105 CTR procedures performed in 96 patients. Median pre-operative NCS Score was 4 with 47% scoring 5 or 6. 4 Patients had died. Post-operative symptom severity scores were low and the majority of patients were very satisfied with the results of surgery.

Despite nerve conduction studies consistent with severe median nerve compression, patients had low postoperative symptom severity scores and overall were very satisfied. Carpal tunnel release in patients over 70 years of age is justified and associated with good outcome.

We compared initial fixation strength of two commonly used tibial side hamstring ACL reconstruction fixation implants – the RCI interference screw and the Intrafix device.

Using a sheep model 36 hamstring grafts were prepared and implanted into the distal femoral metaphyseal bone using either a RCI screw or an Intrafix device. They were then pulled out until failure using an Instron Materials Testing Machine. Maximum strength of graft fixation and mode of failure were recorded.

The average strength of the graft was 48kg using the RCI screw and 90 kg using the Intrafix device. This difference was statistically significant. The maximum pull-out strength was 91kg for the RCI screw and 130 kg for the Intrafix device. The most common mode of failure in the RCI screw fixation was graft shredding on the screw and whole graft pullout whereas in the Intrafix device it was intratendinous failure.

The Intrafix device demonstrated a clear strength advantage over the RCI screw with regard to initial fixation strength. The Intrafix device may reduce tibial side graft creep which is a problem with hamstring ACL reconstruction.

The aim of this surgery was to determine current practice amongst orthopaedic surgeons in New Zealand with regard to Anterior Cruciate Ligament Reconstruction.

All current members of the NZOA were sent a questionnaire on the numbers and proportions of grafts performed, methods of fixation, operative technique and return to sport.

One hundred and ten of 140 questionnaires were returned completed. Ninety two orthopaedic surgeons were performing ACL reconstructions. Eight per cent performed patellar tendon grafts in preference to hamstring grafts, whereas 16% preferred hamstring over patellar tendon grafts. Almost 2000 patellar tendon grafts at an average of just over 20 per surgeon are performed each year compared to just over 500 hamstring grafts at an average of just over 15 per surgeon. Metal interference screws were the most common fixation device in patellar tendon and hamstring grafts.

Patellar tendon grafts are the most common grafts used for ACL reconstruction with 80 % of those surveyed preferring to use patellar tendon over hamstring grafts. Metal interference screws were the most common fixation device. There is reasonable consensus regarding return to activity and sport.

Introduction: Large cysts of the proximal tibial metaphysis are an uncommon radiological finding amongst the elderly presenting to an arthroplasty clinic. We present two cases of such pathology in elderly patients. These were both associated with advanced degenerate disease in the knee.

In view of the size of the lesions these were both fully investigated with pre-operative radiology and an image guided biopsy. The first case was found to be a large degenerate myxoid cyst involving the majority of the tibial plateau. The second case appeared similar radiologically yet was a large metastasis from a bladder cancer. The only history offered by the after this had been established was that she had had a benign polyp removed some years previously.

Management: When dealing with unusual features of disease a cautious approach should be recommended. Both patients underwent staging investigations and biopsy prior to knee replacement surgery. In each case it was possible to graft the defect and using revision prostheses a good outcome has been achieved.

Conclusion: Large cysts appearing in association with degenerate disease of the knee are uncommon. Whilst these will often be related to the underlying arthritis this is not always the case and appropriate care should be taken to establish a diagnosis prior to surgery.

To determine whether increased sagittal laxity has an effect on functional outcome following posterior cruciate retaining total knee replacement using two differing tibial insert designs.

Ninety-seven patients were reviewed clinically, radiologically and underwent KT1000 testing of their TKR at a minimum follow up of 5 years (mean 6.5 yrs). The femoral component design was the same in all patients (Duracon/PCA). Fifty two patients had a relatively flat tibial insert design (group 1), while 45 patients had an AP lipped insert (group 2) following a change in design in 1995.

The 2 groups were comparable for age, sex, Charnley category, BMI, tibial slope and follow up. There was no significant difference in laxity measurements, IKS or WOMAC scores between the groups. There was no significant correlation between laxity and outcome score or flexion range.

Increased sagittal laxity in a knee replacement does not have a strong influence on functional outcome. The differing tibial insert designs had no significant effect on either laxity or function.

Aims: Palacos cement is one of the commonest types of bone cements used in joint replacement surgery. It contains peanut oil which is used as a diluent for Chlorophyll to give the green colour. The manufacturer’s instruction states that it is a contra-indication to use Palacos cement in patients allergic to peanut. The aim of our study was to check the awareness among the orthopaedic surgeons of this contra-indication and find their views on using Palacos cement in patients allergic to peanuts.

Methods: We conducted a postal questionnaire survey among all the orthopaedic surgeons and trainees in Wales, enquiring about their prior knowledge of the contra-indication and their views on what should be done if the patient undergoing arthroplasty has peanut allergy.

Results: There was a response rate of 71%. Only 20% of the consultants and only 40% of the trainees were aware of the contraindication. There were widely conflicting views on what should be done if the patient has peanut allergy. Those views included using different cement, using uncemented implant, seeking second opinion and some suggested they would still continue to use Palacos cement despite history of peanut allergy.

Conclusions: Majority of the orthopaedic surgeons in our study were not aware of the contraindication. This is surprising as peanut allergy could be life threatening. But we are unaware of any reported case of allergic reaction in peanut allergic patients. Review of the literature also suggests that as the peanut oil in Palacos cement is highly refined peanut oil, it is very unlikely to produce allergic reaction in peanut allergic patients. There is no evidence-based reason to support the manufacturer’s advice that Palacos cement should not be used in patients allergic to peanuts.

Objective- To review the 10-year results of 269, cemented total hip arthroplasties performed using matte surface finish Harvard femoral stem that is almost similar to Charnley femoral stem.

Design- Retrospective cross sectional survivorship study.

Patients and Methods- We retrospectively reviewed the results of 269 cemented total hip arthroplasties performed using Harvard femoral stem in 257 patients (M:F, 93:164. Mean age 71.2 years) between 1990–1994. We also reviewed a group of 51 patients who had hip arthroplasty performed on the contralateral side using cemented Charnley femoral stem. Radiographs were reviewed to evaluate following parameters: type of osteoarthritis, cement mantle thickness, alignment of the components, presence of aseptic loosening and radiolucent lines. Kaplan-Meier survival analysis was performed to calculate the survival of Harvard and Charnley femoral stem using various end points. Cox proportional-hazard analysis was performed to evaluate the impact of various radiological parameters on the prosthesis survival.

Results- Out of the 248 eligible patients (260 hips), 6 patients (7 hips) were lost to follow up and 67 patients were dead at the time of the study. 36 hips (35 patients) underwent revision surgery for aseptic failure (Median duration: 60 months, range: 12–125 months) and 11 hips were revised for septic failure (Median duration: 24 months, range: 10–53 months) from the index procedure. Femoral component was revised in all patients whereas acetabular component was revised in 27 patients. 10 year survival for the femoral and acetabular components using aseptic loosening (with and without revision surgery) as an end point was 77.5% (71.5%-83.5%) and 91.1% (87.2%-95%) respectively. Cox regression analysis did not reveal statistically significant (p> 0.05) impact of various radiological parameters on survival rate.

The 10 year survival in the bilateral hip arthroplasty group for the Charnley femoral component (Median follow up 138 months) and Harvard femoral component (Median follow up 120 months) using aseptic loosening as an end point was 95.2% (92.4%-98%) and 77.2% (69.2%-85.2%) respectively.

Conclusion- Our results suggest that the matte surface finish femoral component has less satisfactory long-term survival rate compared to smooth surface femoral stem with similar geometry.

Revision hip surgery is becoming increasingly common, 300 procedures being performed in 2001 at our institution. In order to achieve a good outcome bone stock needs to be of good quantity frequently necessitating the use of impaction bone grafting using allograft bone.

Donor bone may frequently take three months before it becomes available for use due to the stringent screening procedure. Donor patients must have a clean bill of health, swabs taken at the time of surgery must obviously demonstrate no growth and blood samples taken at donation and an interval of three months, free from viral infectious diseases. It is thus easy to see the lag from the time of donation to availability and why, with increasing demand, need for allograft bone is rapidly exceeding supply.

We need to look for an alternative supply of human bone allograft.

We have compared the harvest of bone at the time of primary total knee replacement with that of the femoral head by both mass and volume. Sixty consecutive patients undergoing primary hip or knee arthroplasty were included in the study, and the masses and volume of the femoral heads compared with that of the total bone cuts in knee arthroplasty. The type of knee replacement used was documented as was whether the femoral head had had a bone block removed. It was found that the mass of femoral heads was 81g, that of knee cuts 95g this is a statistically significant difference; the volume of femoral heads 66ml and that of knee cuts 75ml.

The volumes of bone available from knee arthroplasty cuts are at least comparable femoral heads obtained using hip replacement and could, perhaps, provide a realistic source of bone allograft.

Objective- To evaluate three femoral cement pressurization techniques in a laboratory setting.

Design- Observational study using a plastic femur (sawbone) model.

Materials and Methods- 12 femoral bone models were cemented and pressurized using three different cement pressurization techniques (standard technique, pressuriser in situ technique, and thumb pressurisation technique). Four sets of observations were taken for each technique. Intramedullary pressure readings were obtained using proximal and distal pressure monitoring transducers. The peak pressure and the time for which the pressure was above a particular cut off level (5 KPa and 100 KPa) were compared.

Results- There were significant variations between the peak pressure and the duration for which the pressure was above 100 KPa. The pressuriser in situ technique yielded significantly (p< 0.001) higher peak pressure both proximally (397.5 ± 40.2 KPa) and distally (597.3 ± 102.4). The standard technique produced the optimum pressure of 100 KPa for significantly (p< 0.001) longer duration proximally and distally (66.8 ± 29.5 and 45.2 ± 15.5 seconds respectively) compared to the other two techniques (less than 5 and 17 seconds for thumb pressurisation technique and pressuriser in situ technique respectively, both proximally and distally). There were no significant statistical differences between the three methods for the time for which the cement pressure was higher than 5 KPa.

Conclusion- Although the pressuriser in situ technique produced highest peak pressure, the standard technique produced optimum pressure for longer duration. The standard technique seems to be adequate to achieve optimum pressurization during femoral cementing without increased risk of embolisation.

Purpose of Study: It has been widely reported that smokers undergoing lumbar spinal surgery are more likely to develop postoperative complications such as pseudarthrosis, superficial and deep wound infection, as well as diminished clinical improvement. New spine instrumentation was developed (SpineLinkTM, Biomet) which enables surgeons to fuse multiple levels by linking single level fusions in series. This is accomplished through titanium links and polyaxialscrews which preserve lordosis without the bending of rods or plates. During an ongoing 5 year prospective investigation on fusion with intrasegmental fixation the authors analysed and compared outcomes in smokers versus non-smokers to determine the impact of this new system on outcomes in smokers.

Materials and Methods: 64 patients who underwent spine fusion with intrasegmental fixation were prospectively studied at Mayday University Hospital beginning in 1997, 54 have sufficient follow-up to be included in the analysis. Patients were assessed pre and postoperatively, both radiographically and clinically, using validated outcome instruments including the SF-36.

Results: There were 54 patients in the analysis (34 patients in the smoker group and 20 patients in the non-smoking group) with an average age of 52 years and an average follow-up of 28 months. 32 patients had multilevel procedures (25 two level, 5 three level, 2 four level). The treatment groups were comparable with respect to demographic, diagnostic (53% spondylolisthesis, 35% degenerative disc disease, 12% other) and surgical variables. No other significant medical problems affected patients in either group. Radiographically there were no pseudarthroses observed in either group. The SF-36 physical health score increased from 22.4 to 40.1 (+18.0) following surgery in smokers compared to an increase from 25.0 to 36.0 (+11.0) in non-smokers. The SF-36 mental health score increased from 36.4 to 45.0 (+8.6) in smokers compared to an increase of 30.8 to 42.7 (+2.9) in non-smokers. Complications included 2 nerve root injuries requiring hardware removal, and 3 deep infections which resolved with appropriate treatment.

Conclusions: There were no differences between smokers and non-smokers in radiographic fusion success or postoperative complications. As expected, smokers had lower SF-36 physical health and mental health scores pre-op, but unexpectedly, smokers had a greater degree of improvement in these scores postoperatively than non-smokers. Thus, from our experience, there is an incremental benefit to the use of intrasegmental fixation in smokers and warrants further investigation.

Purpose of Study: To prospectively study the outcome of lumbar interbody fusion with an intrasegmental device, and to determine whether smoking, previous surgery and multiple level surgery have an effect on fusion rate.

Methods Used: Between October 1998 and July 2001, 67 patients underwent lumbar interbody fusions using an intrasegmental pedicle screw system (Biomet, Spinelink). Prior to surgery Short Form 36 (UK Version 1) (SF36) scores, pain visual analogue scores (VAS) and patient demographics were recorded. Postoperative follow up was in a specialist spine clinic. Patients were followed up in this clinic until fusion was judged to have occurred both clinically and radiographically. Fusion was judged to have occurred radiographically when there was evidence of a fusion mass at all fused levels and absence of pedicle screw loosening and/or metal work breakage. Patients who were not judged to have fused were classified as either a pseudarthrosis, or indeterminate. Patients completed a questionnaire on attendance at clinic, or by post if discharged. This included an SF36, Oswestry Disability Index, employment status, analgesic use and patient satisfaction assessment.

Results: 67 patients (38 male and 29 female) were successfully followed up. The mean age was 45.2 (range 17–86). Mean follow up was 21.7 months (range 12–43 months). 36 posterolateral fusions and 31 combined posterior lumbar interbody/posterolateral fusions were performed. 22 patients were smokers and 45 non-smokers or ex-smokers at the time of surgery. 18 patients had undergone previous surgery (either discectomy, decompression or fusion). 34 patients had 2 vertebral levels fused, and 33 patients more than 2 vertebral levels.

There was radiographic evidence of fusion in 81.3% of patients. There was an improvement in mean pain VAS, and mean scores of all physical components of the SF36. Patient satisfaction was high (71%).

Subgroup analysis demonstrates that the fusion rates in non-smokers versus smokers, and primary fusions versus previous surgery, were the same. The fusion rate following multiple level fusions was lower at 72.2%.

Conclusions: The results of our study suggest that high fusion rates can still be achieved in high risk patients when an intrasegmental device is used.

Aim: To evaluate our results of articulated hip distraction in children with a painful, stiff hip.

Materials & Methods: Between 1988 & 2003, 10 children underwent hip distraction and 7 have completed treatment. The diagnoses were varied, though the presentations were those of pain & stiffness of the hip, poor posture and gait. The Orthofix articulated hip device was used in all patients. The outcome assessment was performed by clinical and radiological review.

Results: The mean age of the patients was 13.7 years (Range 12–17 years). The primary diagnosis was SUFE- 3, Perthes-4, trauma-1, septic arthritis -1, chemotherapy induced -1. The mean fixator time was 12 weeks (range 10–14 weeks). The follow-up period ranged from 4–183 months. Soft tissue releases and joint debridement were done in 6 and 2 patients respectively. Results were good in one, fair in five and poor in one patient. Patients with non-functional ankylosis gained functional position with some increase in range of motion. Grade 2 pin tract infections were noted in 4 patients.

Conclusion: Early results with hip distraction in this difficult, complicated group of patients are promising clinically and radiologically.

Aims: The purpose of this study was to review the success rates of a new management strategy when dealing with deep infection in knee arthroplasty.

Methods: Since 1998 a management plan consisting of an initial debridement, insertion of vancomycin loaded prostolac spacers and 2 weeks of intravenous antibiotics has been used. If inflammatory indices are improved at 12 weeks reimplantation occurs with antibiotic treatment until cultures are completed. The necessary data has been prospectively collected and reviewed to identify predictors of success.

Results: 34 patients have been identified with a minimum of 12 months follow up. 27 of these have at least 24 months follow up. With an endpoint of a functioning prosthesis clear of infection we have achieved an 82% success rate. If the inflammatory indices and frozen section were normal at the time of reimplantation this was 90% predictive of a successful outcome. Although 13 patients had a combination of abnormal blood tests, cultures and frozen sections at the time of reimplantation only 4 of these went on to develop recurrent infection. 2 patients with normal investigations at reimplantation went on to demonstrate residual infection.

Conclusion: Short courses of parenteral treatment can produce comparable results to previously published series when treating deep infection after knee replacement. Allowing weight bearing and range of motion exercise does not appear to hamper the eradication of infection. None of the investigations currently employed have been shown to be 100% reliable in this series of cases. Whilst attention to detail and careful planning are pre-requisites for this surgery one still has to prepared for failure.

Introduction: Enlarging cystic cavitations (syrinxes) form within the spinal cord in up to 28% of spinal cord injured patients. These post-traumatic syrinxes can cause neurological deterioration, and treatment results remain poor. Syrinxes are often found adjacent to regions of arachnoiditis.

The understanding of biological systems is increasingly dependent on modelling and simulations. Numerical simulation is not intended to replace in vivo experimental studies, but to enhance the understanding of biological systems. This study tests the hypothesis that pressure pulses in the SAS are high adjacent to areas of arachnoiditis and investigates the validity of a numerical model by comparison with in vivo experimental findings.

Methods: Experimental Model: Post-traumatic syringomyelia was induced in eight sheep by injection of kaolin into the subarachnoid space (SAS), and excitotoxic amino acid into the spinal cord of the upper thoracic spine. Cerebrospinal fluid (CSF) pressure studies were undertaken at either 3 or 6 weeks. Fibre-optic monitors were used to measure the pressure in the SAS 1 cm rostral and 1 cm caudal to the induced arachnoiditis.

Numerical Model: An axisymmetric fluid-structure interaction model was developed to represent the spinal cord and SAS under normal physiological conditions and in the presence of arachnoiditis. Arachnoiditis was modeled as a porous obstruction in the SAS.

Results: In both models the SAS pressure rostral to the arachnoiditis was found to be higher than the caudal SAS pressure. There was no statistically significant difference between the sheep at 3 and 6 weeks. Under normal conditions, both experimentally and in the numerical model, the pressure drop along the SAS was negligible. In the presence of arachnoiditis, the pressure drop across the arachnoiditis in the experimental model was 1.6 mmHg, whereas the numerical model predicted a pressure difference of 1.3 mmHg.

Discussion: The numerical model accurately predicts CSF pressures in the animal model under both normal and abnormal conditions, allowing predictions to be made to within 20% accuracy. The local increases in SAS CSF pressure demonstrated may act to increase fluid flow through perivascular spaces and be implicated in syrinx formation and enlargement.

Introduction: This study aimed to analyse immunohis-tochemically the proteolysis of Amyloid Precursor Protein (APP) using Caspase-3-mediated APP proteolytic peptide (CMAP), beta-Amyloid (Aβ) and Active Caspase-3 in post-mortem human specimens in acute and chronic compressive myelopathy.

Compressive myelopathy, occurring through traumatic fracture/dislocation of vertebrae, iatrogenic injury, cervical spondylotic myelopathy (CSM), or metastatic tumour, causes much socio-economic and emotional disability for patients as well as physical consequences. In such conditions, APP is recognised as an early and specifi c marker of axonal injury. The proteolysis of APP in both acute and chronic compressive myelopathy has not yet been described. Studies analysing axonal injury after brain trauma suggest a role for Caspase-3 in the cleavage of APP¹. In addition, Caspase-3-mediated cleavage of APP has been found to be associated with the formation of Aβ, a neurotoxic protein thought to contribute to cell death in Alzheimer’s disease². Furthermore, A? may subsequently encourage activation of Caspases −2, −3, and −6, the major effector molecules in apoptosis². The current study addressed two hypotheses; that APP provides a substrate for the Caspase-3 enzyme, and, that this event is associated with Aβ production in the compressed spinal cord.

Methods: Spinal cord material from 17 patients with documented SCI was analysed. The spatial distribution of cellular immunoreactivity was qualitatively assessed in injury due to trauma (n=5), iatrogenic event (n=1), CSM (n=6) and metastatic tumour (n=5). Morphological, immunohistochemical and immunofl uorescent techniques were used to investigate APP proteolysis.

Results: Caspase-3, APP, CMAP and Aβ were present in anterior horn cells of the grey matter and axons of the white matter. An association was found between neuronal immunoreactivity and that of axons in motor tracts. Dual-immunolabelling revealed axonal co-localisation of CMAP with Aβ and Caspase-3 with Aβ. Although CMAP was present in axons which were immunoposi-tive for APP, an inverse relationship was found as each marker was limited to its own, distinct region, consistent with the theory that CMAP actively cleaves APP. In neurons, co-localisation occurred between Caspase-3 and Aβ, and CMAP with Aβ. No neuronal co-localisation was shown between CMAP and APP in the acute and chronic state.

Discussion: Caspase-3 appears likely to contribute to the proteolytic cleavage of APP in compressive myelop-athy. CMAP was associated with the production of Aβ as demonstrated using single and dual immunolabelling. Furthermore, evidence is given for the association of Caspase-3 itself with the neurotoxic peptide, Aβ. It is possible that activation of Caspase-3 via these secondary mechanisms may trigger the advancement of the apoptotic cascade with the subsequent demise of the cell.

Background The complex ranges from mild epispadias to devastating cloacalexstrophy. Affected babies require multidisciplinary care. The orthopaedic surgeon may assist either directly, in releasing the midline by pelvic osteotomies or indirectly, by advice and treatment of musculoskeletal symptoms related to disturbed mechanics or deformity in the spine, pelvis and lower limbs.

Traditional osteotomies are posterior or horizontal. A technique of an oblique osteotomy from the sciatic notch to the iliac crest has been developed at Great Ormond Street since 1996, along with a system of external fixation. It is undertaken concurrently with urological reconstruction. The system of external fixation is relatively simple compared with other published work.

Methods We reviewed the results of 45 oblique osteotomies performed in conjunction with genito-urinary repair of classical and cloacal bladder exstrophy. Average follow-up was 37 months. Clinical outcome measures were pain, function, continence and normal gait. All radiographs were reviewed and the pubic intersym-physeal diastasis was recorded pre-operatively and on the latest post-operative x-ray. Children were grouped according to the age at the time of osteotomy.

Also children with classical exstrophy were divided into 4 groups on the basis of continence.

The mean post-operative percent reduction in the amount of the original diastasis was determined for all age groups. Comparison of pubic approximation was made between the two types of post-operative immobilisation

Results The majority of patients (42) reported no pain or functional disability. Six cases had a waddling gait pattern and 2 had residual external rotation. All the wounds healed and every osteotomy united.

The average improvement in pubic approximation was 37% for the whole series. Chidren who were older at the time of surgery (18–60 months) were found to maintain better correction over time (76%).

Children immobilised with an external fixator maintained better closure of the pelvis than those treated with plaster cast alone. (51% and 12.2% respectively). Maintenance of pubic approximation was associated with a higher level of bladder continence.

Complications included 3 cases of infection and loosening of the external fixator requiring early removal. There were no neurovascular complications.

Conclusion Oblique pelvic osteotomy is an effective part of the reconstruction bladder exstrophy and compares well with other types of osteotomy.

It is a reliable operation and the technique is applicable to all age groups.

Technique of Oblique Pelvic Osteotomy Oblique pelvic osteotomy is performed by first placing the patient in the supine position, preparing and draping the lower part of the body from the costal margin to the mid-thigh. Intravenous antibiotic prophylaxis is administered and continued for a 24-hour period.

Initially the Urologist will make an infra-umbilical incision then identify and mobilise the anatomical structures intended for their subsequent reconstruction and repair. This wound is then temporarily closed.

The Orthopaedic surgeon will then approach the ilial crest through bilateral oblique incisions made inferior to the anterior superior ilial spine as described for the Salter osteotomy

The interval is developed distal to the anterior superior ilial spine after identification and protection of the lateral femoral cutaneous nerve which is taken medially. After the interval between sartorious and tensa fascia lata are identified the iliac apophysis is split and reflected off the inner and outer ilial crests. The exposure may be improved by also developing the interval between rectus femorus and gluteus medius. Each side of the pelvis is exposed sub-periosteally from the iliac crest extending into the sciatic notch.

A Gigli saw is then passed through the sciatic notch. The line of the osteotomy is from the posterior part of the sciatic notch extending anteriorly and superiorly to exit the iliac crest 2cm posterior to the anterior superior iliac spine (figure 2). The most anterior 1.5cm of iliac crest from the distal pelvic fragment is trimmed to allow closure of the iliac apophysis after rotation.

The size of the half pin utilised is determined by the age of the patient. A baby under 18 months old will have a 3.5mm pin from the AO wrist external fixator frame and an older child over 2 years, a 4.5mm half pin. One half pin is inserted on each side of the pelvis. The half pin is placed in the distal fragment from anterior and lateral to posterior and medial with the tip of the screw just exiting the cortical bone of the medial aspect of the sciatic notch (figure 3a). Consideration of pin placement must take into account rotation of the distal fragment and preventive skin pressure areas. The iliac apophysis is repaired and the skin wounds are closed.

The Urologist completes the reconstruction procedure planned via their infra-umbilical approach.

The final stage involves the medial and superior rotation of both distal pelvic fragments and subsequent closure of the symphyseal diastasis. This position is maintained with the application of an anterior A-shaped frame from the wrist, AO fixation set in the younger infant or the AO pelvic fixator in the older child (figure 3b).

Symphyseal approximation is confirmed intra operatively by palpatation. Bilateral above knee front slabs casts are applied to prevent kicking the hips or knees.

The post-operative management involves pin site care on alternate days. The front slab casts are removed at 3 weeks and the anterior A-frame is removed at 6 weeks after union is confirmed on a pelvic radiograph. Depending on the social situation the children may go home during the post-operative period.

Aims: The aims of this study were to evaluate the biomechanical properties and mode of failure of four methods of fixation of hamstring anterior cruciate ligament (ACL) grafts. The fixation methods investigated included titanium round headed cannulated interference (RCI) screws, bioabsorbable RCI screws, Endobuttons and Bollard fixation. A 2-strand equine extensor tendon graft model was used because a previous study has shown it to have equivalent biomechanical properties to that of 4-strand human semitendinosus and gracilis tendon grafts.

Method: Thirty-two stifle joints were obtained from skeletally mature pigs, the soft tissues were removed and the ACL and PCL were sacrificed. Tibial tunnel preparation was standardised using the Mayday rhino horn jig to accurately position a guide wire over which an 8mm tunnel was drilled. A 2-strand equine tendon graft was then introduced into the tibial tunnel and secured with either a titanium RCI screw, a bioabsorbable RCI screw, an Endobutton or an expansile Bollard. The proximal part of the graft was attached to the crosshead of a materials testing machine using the Soffix. Five of each method of fixation were tested mechanically to ultimate failure and under cyclical loading.

Results: The mean ultimate tensile loads (UTL) were: titanium RCI screw = 444 N, bioabsorbable RCI screw = 668 N, Endobutton = 999 N and Bollard = 1153 N. The mode of failure for all RCI screws involved progressive tendon slippage past the screw. Under cyclic loading conditions the titanium and bioabsorbable RCI screws rapidly failed after several hundred 5 to 150 N cycles due to tendon damage and slippage. Both the Bollards and Endobuttons survived 1500 cycles at 50–450N, with less tendon slippage.

Conclusion: Titanium and bioabsorbale RCI screws provide poor initial fixation of tendon grafts used for ACL reconstruction and fail rapidly under cyclic loading. Both Bollards and Endobuttons provide sufficiently high UTL’s and survive cyclic loading to allow early postoperative mobilisation and rehabilitation. Caution must be used in the early postoperative period when using interference screws to secure a hamstring tendon graft because early progressive tendon slippage may result in excessive graft elongation and early clinical failure.

The reported revision rate of total hip arthroplasties (THAs) due to wear and osteolysis is around 10% at 10 years. However, the actual rate is probably higher: the incidence of osteolysis is reported to be 10% to 45%. Apart from design improvements, improved or new materials and/or and combinations are important in reducing particle-induced osteolysis, especially in young and active patients.

Wear reduction of up to 40% after inert gas sterilisation of polyethylene (PE) has been demonstrated, both in vitro and in vivo. An effective means of providing further increases in wear resistance is to cross-link PE extensively. Early clinical results of non-melt-annealed PE at three years showed wear reduction of up to 85% compared to inert gas radiation-sterilised PE.

In hip joint simulator investigations, bearings with a ceramic ball-head articulating against a composite cup demonstrated wear rates similar to those of ceramic-ceramic bearings. The wear particles are benign. Clinical data collected over two years suggest no disadvantages compared to the standard articulation controls.

The wear resistance of alumina-alumina articulation has been enhanced. In-vitro investigation demonstrated that even with a cup inclination of 60° the wear rate is not increased. The effect of micro-separation of the artificial joint is also minimised. Several prospective multi-centre alumina-alumina studies have shown no additional complications with this articulation. However, alumina is a brittle material with an inherent risk of fracture. The addition of 25% zirconia to alumina (ZTA) in the manufacturing process improves its fracture resistance, increasing its strength by more than 50%, while maintaining its other properties. The wear properties of ZTA are even better than that of alumina, especially in micro-separation articulation mode.

Highly cross-linked and optimised PE and composite technology are promising concepts in address wear particle-induced osteolysis.

The ‘first generation’ Metal on Metal bearing devices was typically produced from cast, high carbon CoCrMo alloy and was in the as-cast condition. They exhibited course, hard primary, and block carbides supported by a softer matrix material. This bi-phasic condition has been verified through reported literature and forensic scientific studies of ‘long-term survived’ retrieved ‘first generation’ devices. The as-cast microstructure of CoCrMo alloys possesses superior wear resistance to the microstructures formed following post cast thermal treatments. It has been well reported that the improvement of mechanical properties, such as tensile or fatigue strength, can be achieved through the thermal treatment of this alloy. Thermal treatments of this alloy have been found to alter its’ microstructure with a significant modification to the carbide phase morphology. The modifications vary with a tendency for a refinement of the carbide size through dissolution of the chromium and molybdenum through solid state solution. Through the examination of the wear patterns of retrieved devices and wear testing of this material in its’ various microstructural conditions, it has been shown that modifications to the carbide morphology, to achieve improved mechanical properties, reduces its’ bio-tribological properties/performance leading to a lower wear resistance. The as-cast carbide morphology is the most mechanically stable condition and with its’ volume fraction, reduces the potential for adhesive wear of the matrix through ‘matrix to matrix’ contact of the two opposing bearing surfaces. It has been reported that abrasive wear is the typical mechanism for metal on metal bearings due to the generation of ‘third body’ particles from carbide asperity tips fracturing during the initial ‘running-in’ period [typically 500k to 1M cycles]. After this stage the carbides become almost level with the surrounding softer matrix material with ‘third body’ scratches dominating the surface topography. Evidence of surface pitting on ‘first generation’ devices [McKee Farrar and Muller] and modern high carbon wrought devices [Metasul] has been attributed to adhesive/fatigue wear following surface-to-surface contact. Therefore, in microstructural conditions, where there is a reduced carbide volume fraction, or no carbides present, wear resistance is reduced. To test this hypothesis two wear tests have been carried out on CoCrMo samples produced from the same chemistry alloy, with varying microstructures, using Calowear [abrasive] and Pin on Dist [adhesive] tests. The as-cast microstructural condition was determined to have the lowest wear coefficient [k=mm3/Nm] in both tests, however statistical significance at 90% confidence interval was only confirmed in the Calowear Test. Examination of wear scars confirmed the mechanical stability of the as-cast carbide phase. It is noted, however that there are papers which have been published offering a divergence of opinion to this hypothesis and which have been considered by this author.

Introduction: This study investigates the influence of surgical approach on the early migration of a cemented Total Hip Replacement (THR), assessed by Roentgen Stereo-photogrammetric Analysis (RSA). Rapid early migration has been correlated with premature implant failure.

Method: 46 patients awaiting THR were allocated into Posterior Approach (PA) and Lateral Approach (LA) groups. RSA was used to assess post-operative stem position and migration at 1 year. Post-operative gait was examined for a subgroup of patients.

Results: There was no difference in initial stem position within the medulla. Significant differences in distal migration were found; (LA 0.78±0.07mm and PA 1.27±0.15mm), p< 0.01. Posterior head migration for the PA group (0.78±0.18mm) was twice that for the LA group (0.46±0.08mm), p< 0.05. The PA group showed greater medial migration of the prosthesis tip (0.62±0.24mm), compared to the LA group (0.11±0.08mm), p< 0.05. During gait, the legs of the PA group were relatively internally rotated when compared to those of the LA group.

Discussion: The PA implants rotate internally and into valgus further than the LA implants. The starting positions of the prostheses were the same with similar cement and prostheses characteristics. We can infer that surgical approach and therefore muscle function have a significant effect upon component migration. During gait, the PA group has relatively internally rotated legs, probably due to short external rotator weakness. Hence, the internally rotating torque on the femoral stem will be larger, explaining the rapid migration in this direction. With the LA approach, the abductors are likely to be damaged. Therefore, the PA joint reaction force will be more laterally directed, explaining the higher coronal plane rotation rates seen in this group.

Conclusion: Profound differences exist in early migration, between the LA and PA. Different muscle function may account for this and probably influences long-term outcome.

The treatment of acetabular dysplasia in adolescents (age> 12) is difþcult and various complex pelvic osteotomies have been described. The aim of surgery being improvement in pain and to delay the onset of secondary osteoarthrosis. Methods: We present our experience of using the Tonnis triple pelvic osteotomy for treatment of acetabular dysplasia in the adolescent and adult age groups (range 13–27 years). This retrospective analysis includes 25 patients operated on over a nine year period (1991–2000) with an average followup of four years (range 2–8 years). More than 50% of the patients had had a previous open reduction or femoral osteotomy for CDH. Results: Radiographic analysis (pre & post op) included CE angle of Wiberg, Sharp-Ullmann index and the acetabular angle of the weight bearing zone. All parameters showed an improvement in the post operative analysis with an improvement in pain and range of movement in all patients. Discussion: The Tonnis triple pelvic osteotomy has the advantage of allowing the operator a direct þeld of view at all times and achieving a great deal of lateral rotation and medial displacement of the acetabulum due to the proximity of the osteotomy to the acetabulum. The ischial ramus and its ligaments to the sacrum are left intact, leading to greater stability of the pelvis and spine. Conclusion: Though technically difþcult and needing a long learning curve, it does improve acetabular alignment and symptoms in the early postoperative years. However long term studies are required to document its effect on the rate of secondary osteoarthrosis.

Aims: The aims of this study were to evaluate the biomechanical properties and mode of failure of four methods of fixation of hamstring anterior cruciate ligament (ACL) grafts. A 2-strand equine extensor tendon graft model was used because a previous study has shown it to have equivalent biomechanical properties to that of 4-strand human semitendinosus and gracilis tendon grafts. Method: Twenty stifle joints were obtained from 10 skeletally mature pigs, the soft tissues were removed and the ACL and PCL were sacrificed. Tibial tunnel preparation was standardised using the Mayday rhino horn jig to accurately position a guide wire over which an 8mm tunnel was drilled. A 2-strand equine tendon graft was then introduced into the tibial tunnel and secured with either a titanium round headed cannulated interference (RCI) screw, a bioabsorbable RCI screw, an Endobutton or an expansile Bollard. Five of each method of fixation were tested mechanically to ultimate failure and under cyclical loading. Results: The mean ultimate tensile loads (UTL) were: titanium RCI screw = 444 N, bioabsorbable RCI screw = 668 N, Endobutton = 999 N and Bollard = 1153 N. Under cyclic loading conditions the titanium and bioabsorbable RCI screws rapidly failed after several hundred 5 to 150 N cycles due to tendon damage and slippage. Both the Bollards and Endobuttons survived 1500 cycles at 50-450N, with less tendon slippage. Conclusion: Titanium and bioabsorbale RCI screws provide poor initial fixation of tendon grafts and fail rapidly under cyclic loading. Both Bollards and Endobuttons provide sufficiently high UTL’s and survive cyclic loading to allow early postoperative rehabilitation.

Introduction: Injury to the wrist may result in derangement of the distal radioulnar joint (DRUJ) and lead to deformity and degenerative changes. This often gives pain on ulnar side of the wrist and limits forearm rotation. We share our experience with the Sauve-Kapandji procedure for chronic posttraumatic derangement of the DRUJ.

Methods: Sixteen patients (seventeen wrists) with chronic posttraumatic derangement of the DRUJ were assessed before and after SauvŽ-Kapandji procedure using Cooneyñs score. There were six men and ten women and average follow up was 64 months.

Results: Mean supination improved from 43.9û to 78.5û and the mean pronation improved from 44.4û to 80.6û at the time of latest follow-up. Pain relief was satisfactory, and the mean grip strength improved from 30.6% of that on the unaffected side preoperatively to 72.1% at the time of follow-up. The ulnar stump was stable in þf-teen patients. Thirteen of the sixteen patients were able to return to work full-time without restrictions. At a mean of 64 months four patients had an excellent result; six a good result; þve a fair result; and one patient a poor result.

Conclusion: On the basis of our þndings, we believe that the index operation is a good salvage procedure for the treatment of chronic posttraumatic derangement of DRUJ, especially when non-operative treatment has been unsuccessful and rotation of the forearm is severely limited.

Aim: We present a review on RSD in children and emphasise the role of multidisciplinary team approach in the management of 13 children. Method: 3 boys and 10 girls with a mean age of 13 years and 4 months were reviewed before and after treatment. They were assessed for pain (visual analogue score) and function. A team-care approach was utilised and co-ordinated by the Orthopaedic Surgeon. Other members included a physiotherapist, clinical psychologist and the pain care team. Results: All the patients received physical therapy (land and hydrotherapy). 5 patients received guanethidine blocks and 10 required psychological support. The time to diagnosis ranged from 2 to 11 months. All the patients improved over a period of 2.5–7 months. Conclusion: Early diagnosis with aggressive multidisciplinary goal oriented team approach should form the basis of management in children with RSD.

Aim: Small amounts of subsidence may be beneficial in stabilising a stem & appears to be a featue of polished tapered stems. Stem rotation (measured as posterior head migration) within the cement mantle, however, is probably a more important mechanism of failure than subsidence. Stems with a wider proximal portion are thought to better resist rotation. The CPS (Endoplus, UK) is such a device; here we compare its’ stability with that of the Exeter (Stryker-Howmedica, UK). Method: 20 patients received the CPS-plus stem & underwent RSA examinations at 3, 6 & 12 months postoperatively. The Exeter 1 year migration data (32 hips) was used as a comparison. Both groups underwent a Hardinge approach & the prosthesis was secured with CMW3G cement. Results: Both stems subsided about 1mm. The CPS showed less medio-lateral & A-P movement of the proximal stem than the Exeter over 1 year, as shown below: 1 Year Mean Migration ± SEM (mm) Discussion: The CPS internally rotates less than the Exeter, as demonstrated by the smaller amount of posterior head migration. It has a lateral flare of the shoulder; making its’ cross-section wider than the Exeter’s, this probably produces a greater resistance to rotation. The CPS also undergoes less medio-lateral proximal stem migration. Its’ lateral shoulder flare is probably responsible for this axial subsidence, as it prevents the shoulder from moving laterally whilst subsiding onto the calcar.

Increasing the width of the proximal section of a polished tapered stem enhances its rotational stability.

Aim: The purpose of this prospective study was to assess the outcome of scarfe osteotomy for hallux valgus. Method: 26 patients were reviewed but only the results of 24 patients (33 osteotomies) were available for analysis. The assessment involved the American Academy Foot and Ankle Society Score, pedobarographic & radiographic examination.

There were 3 male and 21 female patients with a mean age of 46 years. The mean follow up was 17 months. Statistical analysis was carried out. Results: The AAFAS score improved from a mean preoperative value of 52 to 89 postoperatively. The mean improvement was 34 (range 12–46). The inter-metatarsal and hallux valgus angles improved from a mean preoperative value of 15 and 31 degrees respectively to a mean postoperative value of 8 and 14 degrees. 22 patients (91.6%) were satisþed with the outcome of surgery. The pedobarographic results will be illustrated. In one patient a fracture occurred intra-operatively and two patients had wound infection which settled with antibiotics. Conclusion: The early results of the scarfe osteotomy for hallux valgus in our hands are encouraging.

Introduction: Impaction grafting has become a popular technique to revise implants. The Norwegian Arthroplasty Registry reports its use for a third of all revisions. Yet, the technique is seen as demanding. A particular challenge is to achieve sufficient mechanical stability of the construction. This work tests two hypotheses: (1) Graft compaction is an important determinant of mechanical stability, and (2) Graft compaction depends on compaction effort and graft properties. Methods: Impaction grafting surgery was simulated in laboratory experiments using artificial bones with realistic elastic properties (Sawbones, Malmö, Sweden). Bone stock was restored with compacted morsellised graft, and the joint reconstructed with a cemented implant. The implant was loaded cyclically and its migration relative to bone measured. In a second study, morsellised bone of various particle sizes and bone densities, with or without added ceramic bone substitutes, was compacted into a cylindrical mould by impaction of a plunger by a dropping weight. Plunger displacement was measured continuously. Results: Initial mechanical stability of the prostheses correlated most strongly with degree of graft compaction achieved. Graft compaction to similar strength was achieved with less energy for morsellised bone with larger particles, higher density, or bone mixed with ceramic substitutes. Conclusion: Initial mechanical stability of impaction-grafted joint reconstructions depends largely on degree of graft compaction achieved by the surgeon. Compaction depends partly on the vigour of impaction, and partly on graft quality. Higher bone density, larger particle size and mixing with ceramic particles all help to facilitate graft compaction, giving a stronger compacted mass with less effort.

Aims: The aim of our study was assess the outcome following intradiscal electrothermal therapy in patients with chronic discogenic back pain. Methods: 57 patients underwent IDET. All patients had an MRI and provocative discography to conþrm that their pain was of disco-genic origin. Pre-IDET, patients completed: a pain visual analogue score (VAS), an employment assessment and a pain diagram. Post-IDET assessment included a VAS, a subjective outcome assessment, an SF36 and an employment assessment. Results: 46 (80.7%) patients with a mean age of 41.2 years (range 16–76) were successfully followed up. IDET performed at one level in 48 patients and at two levels in 9. The mean follow-up was 19 months (Range 12–32 months). There were 27 males and 19 females. There were no serious complications. The mean pain VAS was 6.6 pre-IDET and 6.3 Post IDET (not signiþcant). 54% of patients stated that they were either Ç much better È or Ç a little better È. Subgroup analysis suggests that neither the presence of mild facet joint arthritis nor undergoing IDET at more than one level has an effect on outcome. Ç Non-organic È preoper-ative pain diagrams (as assessed by principles described by Mann et al) had a signiþcant negative effect on outcome, with patients in this group having a having a deterioration in VAS from 6.75 to 8.3 and only 10% stating that their pain was Ç a little better È and none Ç much better È. Conclusion: We believe that our study demonstrates that IDET can achieve satisfactory results in the treatment of chronic discogenic low back pain, but that patient selection is important in achieving this outcome.

Objectives: The aim of this study was to determine the outcome of posterior lumbar fusion performed using an intrasegmental pedicle screw device.

Design: Prospective Case Series.

Subjects: 83 consecutive patients underwent posterior lumbar fusion for the intrasegmental pedicle screw device between October 1998 and November 2001. The mean age was 46.8 (range 17–86) and 46 were male and 37 female. 40 patients had a single intervertebral level fusion, 34 two level and 7 three level. 23 patients had undergone previous spinal surgery and 29 were smokers.

Outcome Measures: Fusion status was assessed using radiographs (lateral, AP and in the plain if the intervertebral disc). To be judged as fused, there had to be an absence of metalwork failure, no pedicle screw loosening and fusion at all levels if a multi-level fusion.

Patient outcome was assessed by means of a visual analogue scale (VAS) for pain, SF36 health assessment questionnaire, a patient subjective outcome assessment, employment status and analgesic usage.

Results: Patients were followed up for a minimum of one year. Fusion was successfully achieved in 80 (96%) patients.

The mean VAS reduced by 2.2 points from 8.2 to 5.9 (p=0.007). There was a significant improvement in all the physical component scores of the SF36. The subjective outcome was either excellent or good in 65% of patients. Analgesia usage reduced in 71% of patients. 4 patients underwent further surgery. One patient died in the post operative period. There was no significant difference in the fusion rate in smokers compared to non smokers, or those that had undergone previous spinal surgery. The subjective outcome was either excellent or good in 59% of smokers, but only 37% in those that had undergone previous surgery.

Conclusions: We believe that our results demonstrate that the use of an intrasegmental pedicle screw device can facilitate high fusion rates with good clinical outcomes in most patients. The fusion rate does not appear to be effected by smoking, or previous spinal surgery.

Aim: Advances in digital imaging have allowed three dimensional reconstructions to be derived from CT images which greatly improve understanding of complex deformities. Selective laser sintering (SLS) is used in the industrial setting to manufacture prototype models from Computer Aided Designs (CAD). This technology can be utilised to convert CT images into accurate three dimensional physical models of the human bony anatomy. This SLS modelling was used as an aid in the pre-operative planning of complex pelvic surgery.

Materials and Methods: Standard pre-operative X-ray of the pelvis and a CT scan was undertaken. Using MIMICS software and selective laser sintering, models of these deformities could be made. The cases included bladder exstrophy and a complex developmental dysplasia of the hip with associated femoral head dislocation. The cost of this was comparable with a CT scan or MRI scan.

Conclusion: These models provide invaluable visual and tactile information to the operating surgeon, accurately demonstrating the abnormal anatomy in an easily comprehensible manner. They allow estimation of the magnitude and degree of corrections necessary and evaluation of bony deficiencies.

Objectives: The aim of this study was to determine the outcome of posterior lumbar interbody fusion using an intrasegmental pedicle screw device in a series of patients with symptomatic spondylolisthesis.

Design: Prospective Case Series.

Subjects: 34 consecutive patients underwent posterior lumbar fusion for symptomatic spondylolisthesis using an intrasegmental pedicle screw device between December 1998 and January 2002. The mean age was 48.6 (range 27–84) and 16 were male and 18 female. 22 patients had a spondylolisthesis at the L5/S1 level, 10 at the L4/5 level, 1 at the L3/4 level, 1 at the L2/3 level. 17 patients had a grade 1 slip, 16 grade 2, and 1 grade 3. 22 patients had a single intervertebral level fused, 10 two levels and 2 three levels.

Outcome Measures: Fusion status was assessed using radiographs (lateral, AP and in the plain if the intervertebral disc). To be judged as fused, there had to be an absence of metalwork failure, pedicle screw loosening and fusion at all levels if a multi-level fusion.

Patient outcome was assessed by means of a visual analogue scale (VAS) for pain, SF36 health assessment questionnaire, a patient subjective outcome assessment, employment status and analgesic usage.

Results: Fusion was successfully achieved in 33 (97%) patients.

The mean VAS reduced by 3.2 points from 8.3 to 5.1 (p=0.0001). There was a significant improvement in all the physical component scores of the SF36. The subjective outcome was either excellent or good in 24 (71%) patients. Of the 26 patients working prior to surgery, 20 (77%) returned to work. Analgesia usage reduced in 21 (61%) patients.

One patient died in the post operative period.

Conclusions: Our study supports the view that good clinical outcomes can be achieved by posterior interbody fusion of symptomatic spondylolisthesis. This particular intrasegmental device enables a safe, simple technique for reduction and fusion of symptomatic spondylolisthesis.

Introduction: Apoptosis, or secondary cell death, has been demonstrated in a number of neurological conditions, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and brain ischaemia. It is well established from studies of acute spinal cord injury that apoptosis seems an important factor in secondary cell death and irreversible neurological deficit. It is only recently that studies have emerged analysing secondary cell death in chronic injury to the cord. In this study, the spatial and temporal expression of apoptotic cells was analysed in acute traumatic spinal cord injury (SCI) (n=6) and chronic myelopathies due to metastatic tumour (n=5), degenerative spondylosis (n=6) and syringomyelia (n=4). The study aimed to demonstrate apoptosis in compressive spinal cord injury and to analyse the spatial and temporal distribution of apoptosis in acute and chronic myelopathy.

Method: Archival material from 21 spinal cords of patients with documented myelopathy during life and definitive evidence on post mortem examination were available for study. The spatial and temporal expression of apoptotic cells was analysed in acute traumatic spinal cord injury (SCI) (n=6) and chronic myelopathy due to metastatic tumour (n=5), degenerative spondylosis (n=6) and syringomyelia (n=4).

Immunohistochemical analysis of each specimen was conducted using markers of apoptosis, as well as the biochemical apoptotic marker TUNEL. A total of 1800 histopathological slides were analysed. Specimens were also analysed using confocal microscopy to identify the immunopositive cell type. A combination of morphological, immunohistochemical and in situ end-labelling techniques were used to investigate the mechanism of cell death in this experiment. The analytical techniques employed were aimed at showing firstly the presence of apoptosis and secondly the size and position of the damaged regions.

Results: Positivity for active Caspase-3, DNA-PKCS, PARP, TUNEL and active Caspase-9 was found in glia (oligodendrocytes and microglia) axons and neurons in both acute and chronic compression above, below and at the site of compression. In chronic compression, the severity of positivity for apoptotic immunological markers was positively correlated with the severity of white matter damage, as measured by APP immunostaining for axonal injury, and Wallerian degeneration. There was no correlation between the duration of chronic compression and immunopositivity for apoptotic markers. In acute SCI, axonal swellings were consistently positive for Caspases −9 and -3, suggesting mitochondrial activation of apoptotic pathways.

Conclusion: Apoptosis occurs in both acute and chronic spinal cord injury. In acute compression, axonal injury is associated with apoptotic immunopositivity of glia and neurons. In chronic compression, apoptosis of oligodendrocytes and microglia correlates with demyelination of axons within the white matter.

Surgical joint stabilisation can be achieved by ligamentous plication or thermal shrinkage, and as such, we hypothesized that there is no difference in mechanical and morphological properties after reduction of laxity in ligaments treated by either technique.

Methods: 30 mature female rabbits underwent either ‘thermal’ treatment of their left medial collateral ligament (MCL) using a bipolar radiofrequency probe, or plication with two 4/O non-absorbable sutures following division along its midsubstance and loaded positioning of the free ends. After 12 weeks convalescence, the animals were euthanised and MCL complexes were procured from left and contralateral knees to undergo viscoelastic (creep) testing, quantitative Transmission Electron Microscopy (TEM) and immunohistochemistry. The TEM data was quantified by two data procurement protocols; computational analysis and manual graticule.

Mean creep strain in both thermal (1.85 +/− 0.32%) and plicated ligaments (1.92+/−0.36%) was almost twice that of the control (1.04+/−0.15%), although there was no difference between treatment modalities. Similar findings were seen in the thermal (1.77+/−0.45%), plication (1.85+/−0.40%) and control groups (0.92+/−0.20%) for viscoplastic deformation. However, collagen morphological parameters of all three groups were significantly different (p< 0.001). The thermal ligaments demonstrated predominantly small fibrils, whilst the plicated group displayed an intermediate distribution of heterogenous fibrils. Immunohistochemistry followed by TEM revealed a sparse random distribution of alpha-smooth muscle actin staining fibroblasyts in both thermal and plicated groups. There was an insignificant difference in computational and manual procurement methods (p=0.84).

Susceptibility to creep, and residual deformation after recovery, is similar after thermal shrinkage or plication, although inferior to intact ligaments. However, the plicated results suggest remodeling on a pre-existing fibrillar scaffold, yet the thermal group demonstrated histomorphometry similar to scar tissue, suggesting de novo synthesis. The absence of contractile myofibroblasts suggests that these cells may have an insignificant role in regulation of matrix tension during healing.

The use of exhaust suit systems is commonplace in arthroplasty surgery where isolation of the surgical team is desirable in an attempt to reduce the risk of infection transmission. Elevated carbon dioxide levels have been reported in the non-clinical setting with such systems the consequences of which can include fatigue, diapho-resis, nausea, headache and irritability.

The aim of our study was to determine the levels of carbon dioxide present within an exhaust suit system during hip arthroplasty and to compare these with the recommended occupational exposure limit levels published by the Health and Safety Executive (HSE).

Data was collected during ten primary hip replacements performed by the same surgeon whilst wearing the Stryker Steri-Shield Helmet Exhaust System. This is a self-contained unit with an integrated blower used in conjunction with a full-length gown. In addition the helmet was fitted with an air-sampling probe connected to a portable infrared CO2 monitor and also a temperature probe. Thus continuous monitoring of both CO2 and temperature level during surgery was possible.

The mean initial CO2 concentration in the helmet at the beginning of surgery was 3 000 parts per million (ppm) and the mean maximum CO2 level recorded was 13 000 ppm. The mean time the surgeon was within an exhaust suit to perform a primary hip replacement was 1 hr 54 mins and for 86% of this time period the CO2 level within the helmet exceeded the recommended level of 5 000 ppm as stipulated by the HSE.

In conclusion we have demonstrated significantly elevated CO2 levels within the Stryker Steri-shield Exhaust Suit System during hip surgery. Surgeons who use this system should be aware of this together with the physical symptoms that may result.

In 1997 the “step-less” SL Plus (Endoprothetik, Rotkreuz, Switzerland) cementless total hip arthroplasty was introduced to our unit. During the passed 12 months, a retrospective study has been performed in order to evaluate the clinical and radiographic results of this arthroplasty. The preliminary results of the first 50 patients to have completed the clinical and radiographic follow-up have been evaluated. Of the 50 patients, 56 primary total hip arthroplasties were performed, in all cases the SL Plus stem was used. In 52 cases the cementless Doetz acetabular cup, made by the same manufacturer, was used. The other 4 acetabular components were: 2 long stemmed cementless components for developmental dysplasia, 1 standard cementless cup and 1 cemented cup, made by other manufacturers. All patients were reviewed clinically and radiographically. The mean follow-up time was 3 years, range 2 – 5 years. The mean Harris Hip Score was 90 (37 – 100). Patient satisfaction was: 98% satisfied, 2% dissatisfied (p < 0.001). Radiographic assessment demonstrated that all 52 (100%) Doetz acetabular cups osseointegrated, with 53 (95%) acetabular cups osseointegrating in total (p < 0.002). Of the SL Plus stems, 44 (79%) osseointegrated (p < 0.002). The following post-operative complications were observed: 2 dislocations, 2 superficial wound infections, 1 myocardial infarction, 1 sciatic nerve palsy and 1 deep vein thrombosis. The overall complication rate is high at 13%, but with no implant related failures. Nevertheless, the preliminary clinical and radiographic results of the SL Plus stem and Doetz acetabu-lar cup total hip arthroplasty are encouraging.

Introduction: Peri-acetabular rotational osteotomy is recognized as the non-arthroplastic treatment for Developmental Dysplasia of the Hip (DDH). This procedure has increased in popularity during the last decade. It aims to restore the acetabular cover over the femoral head and thus delay secondary osteoarthritic changes in the hip.

Materials and methods: We reviewed 16 patients who underwent peri-acetabular rotational surgery at our hospital. The indication for surgery was DDH in all cases. Reinert’s approach was used for surgical exposure. Two patients underwent a valgus femoral osteotomy at the same time. Mean age was 40 years (range 15–49). The mean follow-up was 46.5 months (range 4–108). The results of the surgery were assessed with radiological indices and a patient satisfaction survey. The radiological indices recorded were Wiberg’s angle, acetabular inclination angle, femoral head extrusion index and Tonnis osteoarthritis grading.

Results: The intervention failed to benefit two patients who subsequently required a total hip arthroplasty. Both patients had Tonnis grade 3 osteoarthritis. One patient developed a necrotic skin flap requiring skin grafting. The mean pre-operative Wiberg’s angle was 11 degrees (range −7 to 25) which was corrected to 35 degrees (range 17 to 58). Mean pre-operative acetabular index was 25 degrees (range 14 to 40) which was corrected to 11 degrees (range of 2 to 21). Mean pre-operative femoral head extrusion index was 37 degrees (range 18–50) which was reduced to 14 degrees (range 0–32). In all but the two patients in whom the surgery had failed, patients reported reduction in hip pain.

Conclusions: Peri-acetabular rotational osteotomy is a challenging but worthwhile procedure for young patients with DDH. The early results from the procedure are encouraging providing patient selection is appropriate. We would like to initiate a debate to identify the ideal patient for this procedure.

Introduction: It has been suggested that arachnoiditis predisposes to post-traumatic syringomyelia formation by obstructing subarachnoid cerebrospinal fluid flow and enhancing perivascular flow into the cord. In an animal model of post-traumatic syringomyelia (PTS), fluid flow in spinal cord perivascular spaces (PVS) is greater at the level of arachnoiditis and syrinx than at other levels and fluid enters the syrinx via the PVS. This study was performed to determine the effects of cerebrospinal fluid (CSF) diversion from the subarachnoid space on perivascular flow and syrinx formation in PTS.

Methods: Twenty six male Sprague-Dawley rats were investigated using the CSF tracer horseradish peroxidase (HRP), the excitotoxic and arachnoiditis model of PTS, and lumboperitoneal shunt insertion. Four experimental groups consisted of syrinx only and shunt only controls, and shunt insertion before or after syrinx formation. CSF flow studies were performed 6 weeks following the final intervention. Grading scales were used to quantify HRP staining.

Results: Syrinxes formed in all animals. Perivascular flow was greatest at the level of the syrinx. Cerebral cortex perivascular flow was significantly reduced following shunt insertion in animals with a syrinx (p< 0.05). Shunt insertion did not alter syrinx length or size, but did reduce the number of animals with evidence of sensory disturbances. There were no significant differences between shunt and syrinx first groups.

Discussion: Increasing distal subarachnoid space compliance does not affect local CSF flow into the spinal cord and syrinx. These results suggest that localised alterations in compliance, as opposed to obstruction from traumatic arachnoiditis, act as an important factor in syrinx pathogenesis.

Aim: To determine the incidence of non-union of the trochanter and the rate of wire breakage encountered using a trochanteric osteotomy as an approach for primary total hip arthroplasty.

Method: 169 complete records were identified for patients who had undergone hip replacement surgery between 1999 and 2001. The age and sex of the patients, prosthesis used and seniority of the surgeon were recorded. The final position of the trochanter and the state of the wires were determined from the x-rays. An assessment was made of the relationship of the tip of the trochanter to the centre of rotation of the hip both pre and post-operatively.

Results: 169 patients. 98 female and 71 male. 118 cases were performed by consultants and 51 cases by registrars. 76% of cases used an Exeter stem, 16% a charnley elite and 8% a C Stem. The most significant determinant of union was the overall shift of the trochanter. In the healed group the average shift was 5.25mm and in the lifted this was 10.42mm(p=< 0.0001).

The average age of the of the patients that healed was 65.4yrs and 70.06 in those that lifted. Again this was significant (p=0.0078).

There was no correlation between sex of the patient, seniority of the surgeon or the prosthesis type with trochanteric union.

Conclusion: The age of the patient and positioning of the implant have a greater effect on the rate of union than the seniority of the surgeon and the patients sex.

We recommend careful planning pre-operatively to limit the change in position of the trochanter.

The relative motion between a prosthesis, the cement mantle and its’ host bone during weight bearing is not well understood. Using Radiostereophotogrammetric Analysis (RSA), we examined the dynamically inducible micromotion that exists at these interfaces when an increased load is placed through the prosthesis.

Dynamically inducible micromotion was measured in the femoral components of 21 subjects undergoing total hip replacement with polished Exeter stems. Two standing RSA studies were performed, at 3 and 12 months postoperatively. Firstly in double-leg stance, and secondly fully weight bearing through the operated hip.

Subjects had no signs of clinical or radiological signs of loosening at 1 year. Significant micromotion was detected at the prosthesis-cement interface at 3 months.

Similar patterns of micromotion were observed at 12 months. The prosthesis appeared to bend during single-leg stance weight bearing, however this accounted for less than half of the total observed movement.

Conventional RSA studies were conducted at 3 months, 6 months and 1 year to confirm that the implants showed normal migration patterns.

This study demonstrates that movement exists between the prosthesis and bone during cyclical weight bearing. This dynamically inducible micromotion probably occurs at the prosthesis-cement interface. It could account for the wear that is observed on the surface of retrieved secure prostheses. This may be a mechanism by which failure eventually occurs.

Introduction: There are approximately 50000 hip and knee arthroplasties performed in the UK every year. With this increasing number the prevalence of periprosthetic fractures is also rising. These are often challenging problems with increased morbidity and mortality. The use of cortical strut allografts in periprosthetic fractures was first reported in the early 90’s with favourable results.The aim of this study was to assess the radiological outcome of cortical strut allografts used as the treatment for periprosthetic fractures of the femur in patients presenting to our institution.

Patients & Methods: 17 patients with who had received strut allografts as part of their treatment for a periprosthetic fracture of the femur were identified. 13 fractures were around a total hip replacement and 4 around other femoral implants (2 long stemmed TKR’s and 2 fracture fixation devices).

We undertook a radiological evaluation of this technique. We assessed fracture union and strut allograft incorporation using the radiological criteria of Emerson et al. The procedure was deemed a success if the fracture had united, with evidence of graft incorporation with a stable implant. We also undertook a notes review identifying any risk factors and any previous surgery.

Results: Two patients died in the early post-operative period. 15 patients were available for analysis. The average length of radiographic review was 16 months. 11/15 procedures (73%) were deemed a success. All these showed evidence of graft incorporation which was time dependent. There were four failures. In one patient the struts fractured at two months. There were three cases of deep sepsis, this required amputation in one and excision arthroplasty in two.

Conclusion: Cortical strut allografts are a good technique for the management of periprosthetic fractures of the femur. As well as providing initial support they also become incorporated which improves the host bone stock.

Introduction: Modern imaging techniques have demonstrated that up to 28% of patients with spinal cord injury develop syringomyelia. Cyst formation and enlargement are thought to be related to abnormalities of cerebrospinal fluid hydrodynamics, however the exact mechanism and route of entry into the spinal cord remain incompletely understood. Previous work in rats has demonstrated that experimental post-traumatic syrinxes occur more reliably and are larger when the excitotoxic injury is combined with arachnoiditis produced by subarachnoid kaolin injection. A sheep model of post-traumatic syringomyelia (P.T.S.) has been characterised and studies of cerebrospinal fluid dynamics are currently being undertaken. The aim of this study was to assess the effect of focal subarachnoid space blockage on spinal fluid pressures and flow.

Methods: Arachnoiditis was induced in 5 sheep by injection of 1.5 mls of kaolin in the subarachnoid space (SAS) of upper thoracic spinal cord. The animals were left for 6–8 weeks before C.S.F. studies were undertaken. In another 5 sheep, a ligature was passed around the spinal cord to simulate an acute blockage of the subarachnoid space. Fluid-coupled monitors were used to measure blood pressure, central venous pressure and subarachnoid pressure (1cm rostral and 1 cm caudal to the arachnoiditis or ligature). Fiberoptic monitors were used to measure intracranial pressure. In the ligature group, subarachnoid pressures were also measured prior to tying the ligature to obliterate the SAS and served as baseline control pressures. The effects of Valsalva and Queckenstedt manoeuvres on SAS pressures were examined in both groups.

CSF flow was studied at 0 and 10 minutes after injection of the CSF tracer horseradish peroxidase (HRP). Vibratome sections of the spinal cord were processed using tetramethylbenzidine and sections examined under light microscopy.

Results: The mean SAS pressure rostral to the arachnoiditis was found to be greater than the mean caudal SAS pressure by 1.7 mmHg. In the ligature group, the difference was 0.9 mmHg, being higher in the caudal SAS. Queckenstedt manoeuvre exaggerated this difference to 3 mmHg in the Kaolin group and 4 mmHg in the ligature group. The effect of Valsalva was much less marked in both groups.

Perivascular spaces were enlarged in most cases of arachnoiditis and HRP was seen to stain these spaces and the central canal within 10 minutes.

Discussion: Post-traumatic syrinxes are usually juxtaposed to the injury site with 80% occurring rostral, 4% caudal and 15%in both directions. The finding of a higher subarachnoid pressure rostral to the injury site may help explain this phenomenon. We hypothesize that a reduction of compliance in subarachnoid space increases the pulse pressure and hence increases perivascular flow of C.S.F. contributing to the formation and enlargement of PTS. We are currently investigating this hypothesis by measuring subarachnoid space compliance directly in the sheep model of arachnoiditis described above.

The use of distal femoral centralising devices has been advocated in order to achieve an even cement mantle. This has been shown to improve femoral component survival but it is recognised that the presence of voids in the mantle has a deleterious effect on the mechanical strength of cement at laboratory testing and in terms of implant survival. The effect of centralising devices on the mantle in relation to the timing of stem insertion has not previously been investigated.

The purpose of this study is to assess the quality of the cement mantle in artificial bone using a polished taper stem with centralisation inserted at different stages of cement cure time and using different cements.

Three cement types were studied, 45‘saw bone’ models were used. The cementation was carried out in an operating theatre at constant temperature of 23.2Ê°C. The cement was mixed according to the manufacturers instructions and pressurised. Early, intermediate and late stem insertion times were determined for each cement type. The late group included stems with and without centralisers. Video recordings of the stem cement interface were made with a 4 mm endoscope after stem removal. Large cement mantle defects were noted in the ‘with centraliser’ group in 7 out of 15 late insertion times and all had small defects in the mantle. None of the ‘without centraliser’ group had cement mantle defects.

Based on our results we advise surgeons to be very aware of the timing of stem insertion when using centralisers.

The Birmingham reSurfacing Arthroplasty (BSA) is a metal on metal prosthesis with no published independent clinical studies. Despite this, it is increasing in popularity, especially as an alternative to stemmed prostheses in younger patients. This study presents the 1year migration results of the BSA femoral component using Roentgen Stereophotogrammteric Analysis (RSA).

Twenty six subjects underwent a BSA, through the postero-lateral approach using CMW3G cement, with RSA marker balls placed intra-operatively. The femoral component migration was measured at intervals of 3, 6 and 12 months using the Oxford RSA system. Geometric algorhythms were used to identify the femoral component. The data was examined for distribution prior to analysis. All statistical analysis was performed using the t-test.

The data was normally distributed. The 1 year migration results of the BSA femoral component are displayed below.

All cemented implants migrate in vivo. The majority of cemented stemmed implant migration occurs within the first post-operative year. High rates of migration within the first post-operative year correlate with premature component failure in some instances. The BSA is a fundamentally different design to most cemented prostheses, despite this we know that very large migrations, those in excess of 2mm/year in any direction are generally regarded as poor indicators of long term outcome. These results suggest that the BSA femoral component is an inherently stable device as it does not migrate significantly within the first post-operative year. Only long-term independent clinical studies and continued RSA follow-up will enable a comprehensive evaluation of the device.

Purpose: In this study we comprehensively evaluate a cohort of profoundly affected adults with Cerebral Palsy. We document hip disability and pain and statistically evaluate the effect of demographic, physical examination (PE) and radiographic parameters on pain and function of the hip.

Methods: We evaluated 77 institutionalized patients with cerebral palsy. Medical history, level of function, pain, and analgesic requirements were obtained from record review and through caregiver interview. Range of motion (ROM), degree of spasticity, decubitus ulcers were documented as well as changes in vital signs and the FLACC pain scale during PE. Radiographs of the pelvis and spine were blindly evaluated without knowledge of the above data. Statistical analysis was performed in order to identify correlations between subjective and objective findings from the history and PE with radiographic parameters in these patients.

Results: Participants included 38 men and 39 women with a mean age of 40 years (range, 22-81), 94 % had severe spastic quadriplegia. Fifteen percent of hips were dislocated and radiographic evidence of arthritis was noted in 23 %. Eighteen percent of hips were definitely painful and 45 % were definitely not painful. Higher rates of dislocation and arthritis were noted in older patients (p< .05). Increased hip pain and perineal care problems were noted in patients with decreased hip abduction (p=.01), windswept hip deformities (p=.02) or flexion contractures (p=.07). Increased spasticity was associated with higher rates of arthrosis, dislocation, pain and decubiti. Hip dislocation and subluxation sig-nificantly correlated with osteoarthritis (p< .0001) but not hip pain. Patients with lower CE (< 20°) or higher Sharps (> 40°) angles were more likely to have a history of hip pain (p=.02). No radiographic parameter correlated with increased analgesic use, or change in FLACC score or vital signs during PE of the hip.

Conclusions: From these adult cerebral palsy patients we document pain and poor perineal care in patients with diminished hip range of motion and windswept hip posture. Hip dislocation and arthritis was noted in 15 and 23 % of hips, with definite pain noted in 18 %. Ace-tabular dysplasia was statistically associated with hip pain; however, in this study we could not correlate hip displacement or arthritis with a history of hip pain or diminished function. Because the incidence of hip pain is low and does not correlate with dislocation or arthritis, we suggest that surgical treatment of hips in severely affected immature patients with cerebral palsy be based on presence of pain or contractures and not on radiographic signs of hip displacement.

Introduction: Loss of nutrient supply, seen in disc degeneration, leads to low concentrations of oxygen and glucose in the centre of the disc. Here we investigate the effect of low nutrient concentrations on the metabolism and viability of the nucleus cells.

Methods: Isolated bovine nucleus pulposus cells were cultured for 24–72 hrs over a range of pH levels and glucose and oxygen concentrations. Changes in metabolite concentrations with time were measured in a purpose-built chamber using embedded electrodes, or biochemically; and metabolic rates determined. On completion, cell numbers were counted and viability assessed.

Results: Metabolic rates varied both with oxygen concentration and with pH. At low oxygen (2% pO₂) and low pH (pH 6.2) for example, oxygen consumption rates and lactic acid production rates were 10–30% those in air at pH 7.4. Low pH in air saturated medium, or low pO2 in neutral medium, reduced metabolism but not as drastically. Glucose concentrations in the range 0.5–5mM in contrast did not affect cellular metabolism. Cells could survive with zero oxygen, although metabolism was seriously dimished; but after 24 hours at low (< 0.5mM) glucose, cell death was observed.

Discussion: Regulation of the concentrations of nutrients in vivo is complex, and depends on both supply and demand. Little is known about cellular demand, and studies such as this could give insight into the situation in the disc in vivo and help determine the cellular consequences of a fall in nutrient supply.

Our results, apart from showing the deleterious effects of low nutrient concentrations, also indicate that isolated cells may metabolise differently from cells in the tissue; at low pO₂ we observed a fall in lactate production, the opposite effect to that seen in tissue previously. The mechanism for this difference is as yet unknown.

This poster describes the separation of a pair of conjoined twins, aged 3 months. They were joined at the pelvis, shared a common hindgut and each had bladder exstrophy. The operation to separate them, done over a weekend, involved paired teams of anaesthetists, Paediatric Surgeons and Paediatric Urologists and one Orthopaedic Surgeon.

The surgeons mobilised and divided the hindgut, giving one twin the distal half and the other the caecum and proximal colon. Two Urologists reconstructed the bladder exstrophies.

The orthopaedic contribution was bilateral oblique pelvic osteotomy to allow midline closure, along with extensive hip releases to deal with severe flexion and abduction contractures.

Both twins survived and are thriving. They have little neurological impairment in the lower limbs and therefore have great potential to walk.

Introduction: Complications of homologous blood transfusion include transmission of infection and development of antibodies. Autologous pre-donation, acute normo-volaemic haemodilution and cell salvage have been used to reduce the use of homologous transfusions.

Surgery for spinal deformities often requires blood transfusion. In February 1999, we started an autologous pre-donation programme for children undergoing spinal deformity surgery.

Methods and results: The case records of the first 15 patients who took part in the programme have been scrutinised and data about pre-donation, haemoglobin, pre- and post-operative hameoglobin, blood loss, blood transfusions, use of blood products, and complications related to pre-donation of blood were obtained and analysed. Similar data from case records of 15 patients, who had surgery for spinal deformities before start of the programme, were used as control.

In the autologous pre-donation group, four received homologous transfusion and 11 escaped exposure to homologous blood or blood products. In comparison in control group 14 out of 15 received homologous transfusion. There was no significant difference between the two groups in terms of diagnosis, operating time, postoperative haemoglobin, body weight and age. Mean operative blood loss in autologous group was less (1190 mls) than in that of the control group (1529 mls).

Of the four patients who received homologous transfusion, two were transfused outside the hospital protocol.

Complications from pre-donation of blood occurred in three patients and were minor. They included minor bruising in two and difficult and painful venous cannulation in one.

Conclusion: In our practice autologous pre-donation resulted in avoidance of homologous blood transfusion in three quarters of patients undergoing spinal deformity surgery. By adopting strategies such as acute normo-volaemic haemodilution, cell salvage and strictly adhering to protocols for prescribing transfusion, we believe that the need for homologous transfusion could be obviated except in extreme cases.

INTRODUCTION: Apoptosis, or secondary cell death, has been demonstrated in a number of neurological conditions, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and brain ischaemia. It is well established from studies of acute spinal cord injury that apoptosis seems an important factor in secondary cell death and irreversible neurological deficit. It is only recently that studies have emerged analysing secondary cell death in chronic injury to the cord. In this study, the spatial and temporal expression of apoptotic cells was analysed in acute traumatic spinal cord injury (SCI) (n=6) and chronic myelopathies due to meta-static tumour (n=5), degenerative spondylosis (n=6) and syringomyelia (n=4). The study aimed to demonstrate apoptosis in compressive spinal cord injury and to analyse the spatial and temporal distribution of apoptosis in acute and chronic myelopathy.

METHOD: Archival material from 21 spinal cords of patients with documented myelopathy during life and definitive evidence on post mortem examination were available for study. The spatial and temporal expression of apoptotic cells was analysed in acute traumatic spinal cord injury (SCI) (n=6) and chronic myelopathy due to metastatic tumour (n=5), degenerative spondylosis (n=6) and syringomyelia (n=4).

Immunohistochemical analysis of each specimen was conducted using markers of apoptosis, as well as the biochemical apoptotic marker TUNEL. A total of 1800 histopathological slides were analysed. Specimens were also analysed using confocal microscopy to identify the immunopositive cell type. A combination of morphological, immunohistochemical and in situ end-labelling techniques were used to investigate the mechanism of cell death in this experiment. The analytical techniques employed were aimed at showing firstly the presence of apoptosis and secondly the size and position of the damaged regions.

RESULTS: Positivity for active Caspase-3, DNA-PKCS, PARP, TUNEL and active Caspase-9 was found in glia (oligodendrocytes and microglia) axons and neurons in both acute and chronic compression above, below and at the site of compression. In chronic compression, the severity of positivity for apoptotic immunological markers was positively correlated with the severity of white matter damage, as measured by APP immunostaining for axonal injury, and Wallerian degeneration. There was no correlation between the duration of chronic compression and immunopositivity for apoptotic markers. In acute SCI, axonal swellings were consistently positive for Caspases −9 and -3, suggesting mitochon-drial activation of apoptotic pathways.

CONCLUSION: Apoptosis occurs in both acute and chronic spinal cord injury. In acute compression, axonal injury is associated with apoptotic immunopositivity of glia and neurons. In chronic compression, apoptosis of oligodendrocytes and microglia correlates with demyelination of axons within the white matter.