Introduction: Seeding of bone or soft tissue tumour along the biopsy tract is a known complication of percutaneous biopsies. Correct surgical management requires preoperative Identification and excision of the biopsy tract at time of surgery. We aim to audit how well biopsy tract sites can be identified preoperatively and investigate factors influencing their Identification.

Method: Prospective audit of patients who had tissue biopsies for bone and soft tissue tumours at the RNOH Stanmore and presented for surgery between February and April 2008. Case note analysis, patient history and examination at the time of surgery used to collect data.

Results: 13/23 patients had their biopsy tract site accurately identified preoperatively, with a mean time gap of 43 days (6–118) between biopsy and excision. In 10/23 patients the biopsy site could not be accurately identified preoperatively. In these patients the mean time between biopsy and excision was 106 days (55–158) (p=< 0.05). 7 patients had neoadjuvant chemotherapy with a mean time gap of 110 days; in 5/7 the tract site was unidentifiable. One patient had preoperative radiotherapy and the biopsy site was unidentifiable.

Discussion: This audit has shown that Identification of the biopsy site is more difficult after 40 days. In order to ensure accurate Identification of the biopsy site an Indian ink tattoo should be considered at time of biopsy. It may be particularly advisable for patients who are likely to require neoadjuvant chemotherapy or preoperative radiotherapy.

On this basis we would recommend that all patients have the biopsy site marked at the time of biopsy and a further audit will be carried out to evaluate this change in practice.

Introduction: The non-invasive growing prosthesis continues to be used successfully for the treatment of limb salvage operations in tumour patients. We report our continued experience in 17 skeletally immature patients with osteosarcoma of the distal femur.

Methods: Patients had a mean age of 10.2 years (range 6 to 15) at the time of surgery. The endoprosthesis was lengthened at appropriate intervals in outpatient clinics without anaesthesia using the principle of electromagnetic induction.

Results: The mean follow-up was 28 months (range 2 to 55). The prostheses were lengthened by a mean of 47.4 mm (range 0.5 to 208) and maintained a mean knee flexion of 110 degrees (range 90 to 120 degrees).

Complications developed in seven patients: two implants failed requiring revision, one peri-prosthetic fracture occurred, one developed a flexion deformity of 25 degrees at the knee joint, which was subsequently overcome and three died of disseminated disease.

Discussion: The medium term results from patients treated with this device have continued to show a promising outcome. Four patients successfully completed desired lengthening, six patients are continuing with ongoing lengthening. The implant avoids multiple surgical procedures, general anaesthesia and assists in maintaining leg-length equality.

Introduction: Pathological fractures commonly undergo biopsy to establish tissue diagnosis and plan definitive surgical management.

Methods: 129 patients undergoing image-guided needle biopsy of a pathological fracture between 1998 and 2007 were prospectively identified. Imaging was by CT, ultrasound or fluoroscopy. Biopsy was by Jamshedi, Temno or Trucut needle. The outcome measure was ability to make a tissue diagnosis by this method.

Results: The median age at diagnosis was 43 years. 59% were male, 41% female. The four most common sites of pathological fracture were the femur (35%), humerus (28%), tibia (12%) and pelvis (11%).

The five most common histopathological diagnoses were chondrosarcoma (9%), osteosarcoma (9%), meta-static renal carcinoma (8%), giant-cell tumour (6%), lymphoma (5%).

77% of biopsies yielded a tissue diagnosis. The remaining 23% underwent open biopsy, repeat image-guided needle biopsy or were not further investigated.

In the 30 cases (23%) of non-diagnostic biopsies 80% of these lesions had no extra-osseous component to them and the remaining 20% had a very small extra-osseous component.

Discussion: A tissue diagnosis of a pathological fracture can be obtained by primary image-guided needle biopsy in 77% of cases referred to a specialist bone tumour service. The majority (80%) of unsuccessful biopsies were of lesions with little or no extra-osseous component to the lesion.

Introduction: Total femoral endoprosthetic replacement can be used as an alternative to hip disarticulation following extensive tumour excision or in cases of more severe bone loss. To date there have been no long term studies on the oncological and functional outcome of patients who have had this procedure for malignant bone disease. We report our experience of over 25 years employing this procedure using a custom-made and modular total femoral endoprosthetic replacement.

Methods: This is a retrospective, single centre study of 27 patients who underwent consecutive total femoral replacement as a primary procedure between 1978 and 2005. Information was collected from the bone tumour database, medical records and clinic review. Outcome was assessed using the Musculoskeletal Tumour Society (MSTS) rating score, the Harris Hip Score (HHS) and the Oxford Knee Score (OKS).

Results: There were 15 males and 12 females, with a mean age of 30 years (5 to 65). The overall mean follow-up was 4.3 years (1 to 16.4) for all patients, 9.1 years (1 to 16.4) for the 7 patients who were alive at the time of this review, and 2.6 years (1 to 13) for the 20 patients who had died. 24 patients had primary malignant bone tumours of the femur and 3 had metastatic disease from a known primary elsewhere. 3 patients developed local recurrence, 1 patient developed new lung metastases. Mean MSTS score was 63% (19/30), mean HHS was 68/100 and mean OKS was 34/48.

Discussion: Total femoral replacement can be an effective alternative to hip disarticulation in patients with malignant bone disease. Good functional outcomes can be achieved without compromising survival.

Our aim was to review the short-term clinical results of a single-institution cohort undergoing opening wedge high tibial osteotomy (HTO).

We undertook a prospective clinical and radiographic review of our cohort of patients who had undergone opening wedge HTO for varus malalignment. The Cincinnati scoring system was used for objective assessment. Pre- and post-operative radiographs were evaluated and Blackburne-Peel (BP) and Insall-Salvati (IS) ratios recorded, as well as integrity of the lateral hinge.

We reviewed 55 knees (51 patients: 34 men and 17 women; mean age, 44.2years; range 34–58years) followed up for a minimum 12 months (range, 12–62months). All patients had relief of pain, but six met our criteria of failed treatment where either revision fixation was required or proceeded to total knee arthroplasty for persisting symptoms. Cincinnati scores were 94.5% excellent (52/55) and 5.5% good (3/55) at 1 year, whilst at last follow-up they were 87.2% excellent (48/55), 9.1% good (5/55) and 3.6% fair (2/55). There was a significant improvement in mean American Knee Society score at 1 year and maintained at last follow-up (p< 0.05). Radiographically the lateral hinge was noted to be breached in 9.1% (5/55), but no incidence of non-union was identified. There was no significant change in IS index, however BP index diminished by a mean 15.3% (range, 7.4–28.2%). Medial opening wedge tibial osteotomy results in patellar infera, but successful clinical and functional outcomes have been demonstrated. The fact ther e is inconsistency between the two indices assessing patellar height ratio we believe reflects the inherent variability in the techniques employed. Distalisation of the tibial tubercle will mean the IS ratio remains unaffected, whilst the BP index more accurately demonstrates the lowering of patella relative to the joint line. However there may be other factors which are not immediately appreciated, such as changes in the tibial inclination or antero-posterior translation.

We retrospectively studied 67 patients who underwent proximal humeral replacement with the Bayley-Walker prosthesis, for tumour of the proximal humerus between 1997 and 2007. Of the 67 patients 10 were lost to follow up. Of the 41 surviving patients, function was assessed using the Musculoskeletal Tumour Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS) questionnaire.

4 of the 41 patients received the new Bayley-Walker ‘captured’ proximal humeral replacement. The mean age was 46 years (7–87). The mean MSTS score at follow-up was 72.0 % and the mean TESS score was 77.2 %. The sub-group of 4 pts who received the new captured prosthesis had a mean MSTS score of 77.7 %. There was no mechanical failure of any prostheses in the follow up period.

Endoprosthetic replacement for tumour of the proximal humerus with the Bayley-Walker prosthesis, is a reliable operation yielding reasonable functional results and good long-term prosthesis survivorship. The performance of this prosthesis is expected to improve further with the new ‘captured’ prosthesis.

Our aim was to review the short-term clinical results of a single-institution cohort undergoing opening wedge high tibial osteotomy (HTO).

We undertook a prospective clinical and radiographic review of our cohort of patients who had undergone opening wedge HTO for varus malalignment. The Cincinnati scoring system was used for objective assessment. Pre- and post-operative radiographs were evaluated and Blackburne-Peel (BP) and Insall-Salvati (IS) ratios recorded, as well as integrity of the lateral hinge.

We reviewed 55 knees (51 patients: 34 men and 17 women; mean age, 44.2years; range 34–58years) followed up for a minimum 12 months (range, 12–62months). All patients had relief of pain, but six met our criteria of failed treatment where either revision fixation was required or proceeded to total knee arthroplasty for persisting symptoms. Cincinnati scores were 94.5% excellent (52/55) and 5.5% good (3/55) at 1 year, whilst at last follow-up they were 87.2% excellent (48/55), 9.1% good (5/55) and 3.6% fair (2/55). There was a significant improvement in mean American Knee Society score at 1 year and maintained at last follow-up (p< 0.05). Radiographically the lateral hinge was noted to be breached in 9.1% (5/55), but no incidence of non-union was identified. There was no significant change in IS index, however BP index diminished by a mean 15.3% (range, 7.4–28.2%). Opening wedge HTO provides a means of relieving stress distribution through the medial tibiofemoral compartment and results in effective relief of symptoms with improvement in functional outcome and quality of life.

Introduction: We report our experience with use of the SMILES prosthesis in primary knee arthroplasty.

Methods: The Stanmore Modular Individualised Lower Extremity System (SMILES prosthesis) has been shown to be effective in complex revision knee surgery. It incorporates a rotating hinge platform knee joint and can overcome the major problems of bone loss and ligamentous laxity.

38 patients (41 knees) who received a primary SMILES knee prosthesis by one of the senior authors between 1990 and 2006 were retrospectively studied. Knee function was assessed pre and post-operatively using the Oxford knee score (0–48 scoring system) and the Knee Society Score. Patients receiving surgery for tumours were excluded. The main indications for primary SMILES were bone loss and ligamentous laxity.

Results: The minimum follow-up was 18 months with a mean of 5 years (1–17). The mean age of the patients was 57.7 years (23–86); 15 of the patients were male. The indications for surgery were trauma (12), osteoarthritis with deficient medial collateral ligament (8), polio (7), rheumatoid arthritis (5), epiphyseal dysplasia (4), achondroplasia (2), avascular necrosis (1), osteogenesis imperfecta (1) and ankylosing spondylitis (1).

2 patients died and 5 were lost to follow-up. 2 patients required revision surgery (one for infection and one for re-bushing). Post-operative complications included peroneal nerve palsy (1) and DVT (1). The mean Oxford knee score improved from 9 pre-op to 44 post-op, and the mean knee society score improved from 24 pre-op to 71 post-op. The average range of motion was 57 degrees pre-op and 88 degrees post-op.

Conclusion: We conclude that the SMILES prosthesis offers significant improvement in clinician and patient assessed outcome scores in complex primary knee arthroplasty. The cost compares favourably with other designs and its use is well established.

Aim: To review the short-term clinical results of a single-institution cohort undergoing opening wedge high tibial osteotomy (HTO).

Method: We undertook a prospective clinical and radiographic review of our cohort of patients who had undergone opening wedge HTO for varus malalignment. The Cincinnati scoring system was used for objective assessment. Pre- and post-operative radiographs were evaluated and Blackburne-Peel (BP) and Insall-Salvati (IS) ratios recorded, as well as integrity of the lateral hinge.

Results: we reviewed 55 knees (51 patients: 34 men and 17 women; mean age, 44.2 years; range 34–58 years) followed up for a minimum 12 months (range, 12–62 months). All patients had relief of pain, but six met our criteria of failed treatment where either revision fixation was required or proceeded to total knee arthroplasty for persisting symptoms. Cincinnati scores were 94.5% excellent (52/55) and 5.5% good (3/55) at 1 year, whilst at last follow-up they were 87.2% excellent (48/55), 9.1% good (5/55) and 3.6% fair (2/55). There was a significant improvement in mean American Knee Society score at 1 year and maintained at last follow-up (p< 0.05). Radiographically the lateral hinge was noted to be breached in 9.1% (5/55), but no incidence of non-union was identified. There was no significant change in IS index, however BP index diminished by a mean 15.3% (range, 7.4–28.2%).

Discussion: Medial opening wedge tibial osteotomy results in patellar infera, but successful clinical and functional outcomes have been demonstrated. The fact there is inconsistency between the two indices assessing patellar height ratio we believe reflects the inherent variability in the techniques employed. Distalisation of the tibial tubercle will mean the IS ratio remains unaffected, whilst the BP index more accurately demonstrates the lowering of patella relative to the joint line. However there may be other factors which are not immediately appreciated, such as changes in the tibial inclination or antero-posterior translation.

Introduction: Blood management in the perioperative period of the total joint arthroplasty procedure has evolved over the last 3 decades. We performed two separate studies:

1) observational study to analyse surgeon’s and anaesthetist’s attitude to transfusion

Method: 500 orthopaedic surgeons and 336 anaesthetists were surveyed to assess current UK attitudes towards transfusion practice following arthroplasty.

200 patients (88 THR, 99 TKR, 13 hip resurfacing) were evaluated. Blood Hb, hand grip strength and vigour scores using fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. POMS and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: In an uncomplicated patient following total hip arthroplasty, 53.2% of surgeons and 63.1% of anaesthetists would transfuse at or below Hb of 8g/dL. Mean transfusion threshold in surgeons was 8.3g/dL compared to 7.9g/dL for anaesthetists (p< 0.01). 97% of surgeons transfused two or more units compared to 78% anaesthetists (p< 0.01). This threshold Hb increased if patient was symptomatic (surgeons 9.3g/dL, anaesthetists 8.8g/dL, p< 0.05), or if known to have pre-existing ischaemic heart disease (surgeons 9.0g/dL, anaesthetists 9.2g/dL, p< 0.05).

A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: Haemoglobin level below 9g/dL is the most common ‘trigger’ for blood transfusion. Surgeons tend to be more aggressive in their attitude to transfusion. A fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.

Introduction: Smoking is associated with impaired wound healing, delayed bony union following fractures and an adverse effect on the immune system. Furthermore, smoking is an important risk factor for the development pulmonary complications following major surgical procedures, as well as wound complications. We determined whether smoking had a deleterious effect on outcome after autologous chondrocyte implantation (ACI) in the treatment of ostechondral defects of the knee.

Methods: We identified 103 (54 females and 49 males) patients with a mean age of 34.2 (range 18 to 49) who had undergone ACI between January 2001 and August 2004 who also had their smoking status recorded. The patients were divided into 3 groups according to their smoking status. The Visual Analogue Score, Bentley Functional Rating Score and Modified Cincinatti Scores were used to assess function pre-operatively, 6 months and then yearly thereafter.

Results: Group 1 consisted of 31 smokers (mean pack years of 13.4), group 2 consisted of 63 non-smokers and group 3 contained 9 ex-smokers. In Group 1, the Modified Cincinatti Score pre-operatively, 6 months, 1 year and 2 years following surgery were 34.1, 42.6, 43.5 and 46.7 respectively. In group 2 the scores were 47.4, 59.6, 59.1, 65.3, and in group 3 the scores were 39.8, 50, 53.3, 51.8. At the 1 year check arthroscopy, the graft failure rate in group 1 was 12% and biopsies revealed mixed hyaline and fibrocartilage in only 25% (there were no patients with hyaline cartilage). There were no graft failures in group 2 and 43.8% of the biopsies performed were either hyaline (12.5%) or mixed hyaline and fibrocartilage (31.3%). The wound complication rate was 24% in group 1 and 8% in group 2.

Conclusions: The results of this study suggest that people who smoke have a worse functional outcome and a higher complication rate following chondrocyte implantation. This association has not been previously described and should be included in the pre-operative counselling of patients undergoing the procedure.

Aim: To report the clinical and histological outcome of autologous chondrocyte implantation (ACI) using two techniques -collagen covered ACI or ACI-C and matrix carried ACI or MACI- over eight year period.

Patients and methods: One hundred and seventy one patients (61 ACI-C and 110 MACI) who underwent ACI were followed-up prospectively using both objective and patient reported clinical outcome measures. Biopsy of the repair tissue was performed in 115 patients.

The mean clinical follow-up was 39.4 months (13mths to 8 years) and the mean timing of biopsy was 14.8 months. The mean age at the time of surgery was 32 years (15 to 55 years). The site of defect was as follows: medial femoral condyle-95, lateral femoral condyle-25, trochlea-7, patella 27 and multiple sites- 12. The mean proportion of viable cells available for implantation was 96.3 % (range: 86 to 100) and the mean number of multiplication of cells during culture was 90 (range: 9 to 667).

Results: 79 % of patients had an improvement in clinical outcome, 5 % of patients had no difference and 16 % had deterioration in clinical outcome. Short Form 36 (SF-36) health survey assessments demonstrated significant improvements in both mental and physical component scores (p< 0.001). The number of patients who demonstrated hyaline-like, mixture of hyaline-like and fibrocartilage, fibrocartilagenous and fibrous tissue histology were 32, 22, 59 and 2 respectively.

The most favourable sites were lateral femoral condyle and trochlea where as the least favourable site was patella. There was no correlation between the mental score of patients and the final clinical result. Improvement in functional score was significantly higher among those who had a higher pre-operative function (p< 0.001). There were 7 patients who had previously failed micro-fracture and all of them obtained significant improvements in pain and function. Those who had a higher proportion of viable cells after cell culture demonstrated a tendency towards better outcome, but failed to reach statistical significance (p=0.14). There was no correlation between the number of cell multiplications at the time of cell culture and final clinical outcome (p=0.65). There was no significant difference in clinical outcome between the ACI- C and MACI techniques of ACI (p> 0.05).

Conclusion: Autologous chondrocyte implantation is a useful procedure for patients with symptomatic chondral defects of the knee and produces significant improvement in both objective and patient reported clinical outcome scores in up to 79 % of patients.

Introduction: Several studies have implicated excessive weight as a negative predictor of success of total knee arthroplasty. In addition, obese patients are known to have increased risk of wound complications after orthopaedic and general surgery. The purpose of this study was to compare the clinical and functional outcomes of autologous chondrocyte implantation for treatment of osteochondral defects of the knee performed in obese patients with those performed in non-obese patients.

Methods: We analysed the data on all our patients that have been followed up for a minimum of 2 years and had their height and weight recorded initially in our database. Functional assessment consisted of Bentley Functional Rating Score, Visual Analogue Score, and the Modified Cincinatti Scores (collected prospectively at 6 months, 1 year, 2 years and 3 years following surgery). Patients were placed into 3 groups according to their body mass index (BMI). Group A consisted of patients with BMI of 20 to 24.9, group B patients with BMI of 25 to 29.9 and Group C are patients with BMI of 30 to 39.9.

Results: There were 80 patients (41 males and 39 females) with a mean age of 35.4 (range 18 to 49). The mean BMI for the entire group was 26.6. The pre-operative, 6 month, 1 year, 2 year, and 3 year Modified Cincinatti Score in Group A (32 patients) was 54.4, 80.3, 82.7, 74.7 and 72.6. Similarly in Group B, the scores were 53, 41, 54, 56, 49.5 and in Group C the scores were 36.3, 36.3, 49.6, 36, and 35.7. The wound infection rate in Group A was 6.25%, in Group B was 17.6% and Group C was 14.3%.

Conclusions: Initial results from this study suggest that BMI is an important predictor of outcome after chondrocyte implantation. The group of patients that would gain most benefit from ACI are patients that are not overweight (defined by BMI in the range of 20 to 24.9). Further work is being carried out to support the hypothesis that surgeons should strongly consider not operating on patients unless the BMI is less than 25.

Introduction: ACI is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We report the minimum 2 year follow-up results of 192 patients randomised to autologous chondrocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) and matrix-induced autlogous chondrocyte implantation (MACI) for the treatment of osteochondral decfects of the knee.

Methods: 192 patients (mean age 34.2) were randomised to have either ACI (86 patients) or MACI (106 patients). 1 year following surgery patients underwent check arthroscopy (with or without biopsy) to assess the graft. Functional assessment was performed yearly by using the modified Cincinatti knee score, the Bentley functional rating score and the visual analogue score.

Results: 24 patients were excluded from the study as they underwent additional procedures (e.g. high tibial osteotomy). In the ACI group the modified Cincinatti score increased from 42.5 pre-operatively to 56.7, 54.1, and 60.4 at 1 year, 2 years and 3 years respectively. In the MACI group the Cincinatti scores increased from 46.0 pre-operatively to 59.9, 58.9, and 58.4. Arthroscopic assessment showed a good to excellent International Cartilage Repair Society score in 90.7% of ACI-C grafts and 68.4% of MACI grafts. Hyaline-like cartilage or hyaline-like with fibrocartilage was found in biopsies of 51.9% of ACI-C grafts and 25.9% of MACI grafts.

Conclusions: ACI grafts are more likely to produce hyaline-like or mixed hyaline-like cartilage and fibro-cartilage with better ICRS grades than MACI grafts. However, this does not translate to better a clinical functional outcome. More importantly, ACI and MACI had similar results that were maintained at 3 years.

We aimed to determine whether proximal femoral bone remodelling, as measured by DEXA scan for each Gruen Zone, differed for 3 different femoral stem designs. These were:

Group 1 – Triple taper polished (C-stem J& J DePuy)

Ethical Committee approval was obtained and all patients gave informed consent. All operations were performed by 3 surgeons using a standard lateral approach, third generation cementing technique and a standard post-operative regime.

Seventy-five patients were randomised prospectively using a stratified randomisation programme for known risk factors in bone density. The randomisation was stratified by age, sex, Charnley Group (A or B), BMI and femoral neck bone mineral density. There were 25 patients in each Group, 5 patients did not have complete data sets and were therefore withdrawn from evaluation.

The Groups were similar with regard to age, sex, BMI, BMD and Charnley Group. Patients were followed up at 3, 6, 12 and 24 months by Nurse Practitioners for clinical and radiological evaluation and DEXA scan at each time of follow-up. There were no catastrophic failures of sepsis or dislocation. All patients functioned well at 24 months by Harris Hip Score.

The bone remodelling pattern will be described for each stem design. Findings are summarised thus. In the lateral Gruen Zones the triple taper and collared stem design faired better and both behaved differently to the double taper design. In Gruen Zone 7, all stems demonstrated reduced bone density as compared to pre-operative scans but this was less with the triple taper design.

46 Sacral chordoma patients treated between 1987 and 2004 are reviewed. The importance of early diagnosis, adequate surgical margin and post operative radiotherapy for optimum outcome and survival is stressed.

There were 33 male and 13 female patients, with a mean age of 61 years (38–73 years). The surgical approach depended on the level and extent of the lesion, with an anteroposterior approach used in 23 and posterior approach in 17 patients. 20 had partial sacrectomy, 17 had subtotal sacrectomy and 3 underwent total sacrectomy. 6 patients were deemed inoperable and received palliative therapy. 14 patients received radiotherapy post-operatively. The length of average follow up was 4.27 years (range 2–15.7 years).

Low back pain was the most common presenting symptom (80%), and 50% patients had a palpable mass. The mean duration of symptoms prior to diagnosis was 2 years (range 1 month–10 years). Examination revealed a palpable mass in 7 both externally and on rectal examination. 10 had a palpable mass on rectal examination but not externally. 2 patients presented with multiple metastases and another 2 with widespread local disease. Excision was complete in 23 patients and incomplete in 17. Histology revealed dedifferentiation in 4. Complete excision margin was achieved in 69.6% through combined approach and 52.9% through posterior approach only. 24 patients (52%) had local recurrence. Without adjuvant radiotherapy the mean disease free period following complete excision was 3.5 years, compared to 0.9 years following incomplete excision. Adjuvant radiotherapy extended the mean disease free period following incomplete excision to 1.8 years.

The authors conclude that an early diagnosis and careful examination is important. Wide excision remains the mainstay of treatment. If excision is incomplete radiotherapy increases the disease free period although local recurrence is inevitable. The use of a combined approach increases the likelihood of complete excision.

Aims: To compare the clinical and functional outcomes of autologous chondrocyte implantation for treatment of osteochondral defects of the knee performed in overweight, obese and patients of ‘ideal weight’as defined by their BMI.

Methods: We analysed the data on all our patients that have been followed up for a minimum of 2 years and had their height and weight recorded initially in our database. Functional assessment consisted of the Modified Cincinatti Scores (collected prospectively at 6 months, 1 year, 2 years and 3 years following surgery). Patients were placed into 3 groups according to their body mass index (BMI). Group A consisted of patients with BMI of 20 to 24.9, group B patients with BMI of 25 to 29.9 and Group C are patients with BMI of 30 to 39.9.

Results: There were 80 patients (41 males and 39 females) with a mean age of 35.4 (range 18 to 49). The mean BMI for the entire group was 26.6. The pre-operative, 6 month, 1 year, 2 year, and 3 year Modified Cin-cinatti Score in Group A (32 patients) was 54.4, 80.3, 82.7, 74.7 and 72.6. Similarly in Group B, the scores were 53, 41, 54, 56, 49.5 and in Group C the scores were 36.3, 36.3, 49.6, 36, and 35.7. The wound infection rate in Group A was 6.25%, in Group B was17.6% and Group C was 14.3%.

Conclusions: Initial results from this study suggest that BMI is an important predictor of outcome after chon-drocyte implantation. The group of patients that would gain most benefit from ACI are patients that are not overweight (defined by BMI in the range of 20 to 24.9). Further work is being carried out to support the hypothesis that surgeons should strongly consider not operating on patients unless the BMI is less than 25.

Aims: To investigate

the influence of histology on durability of cartilage repair following collagen-covered autologous chon-drocyte implantation (ACI-C) in the knee.

Patients and methods: The modified Cincinnati scores (MCRS) of eighty-six patients were evaluated prospectively at one year and at the latest follow-up (mean follow-up = 4.7yrs. Range = 4 to 7 years). Biopsies of their cartilage repair site were stained with Haema-toxylin and Eosin and some with Safranin O and the neo-cartilage was graded as hyaline-like (n=32), mixed fibro-hyaline (n=19) and fibro-cartilagenous tissue (n=35). Macroscopic grading of the repair tissue using the international cartilage repair society grading system (ICRS) was available for fifty-six patients in this study cohort. Statistical analyses were performed to investigate the significance of histology and ICRS grading on MCRS at 1 year and at the latest follow-up.

Results: The MCRS of all three histology groups were comparable at one year evaluation (p=0.34). However, their clinical scores at the latest follow-up showed a significantly superior result for those with hyaline-like repair tissue when compared to those with mixed fibro-hyaline and fibro-cartilagenous repair (p=0.05).

There was no correlation between the ICRS grading and MCRS either at one year (p=0.12) or at the latest follow-up (p=0.16). Also, the ICRS grading of the repair tissue did not correlate with its histological type (p=0.12).

Conclusion: We conclude that any form of cartilage repair gives good clinical outcome at one year. At four years and beyond, hyaline-like repair tissue produces a more favourable clinical outcome. Macroscopic evaluation using the ICRS grading system does not reflect the clinical outcome or its durability or the histological type of repair tissue.

Purpose: We report on minimum 2 year follow-up results of 71 patients randomised to autologous chon-drocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) for the treatment of osteochondral defects of the knee.

Introduction: ACI is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autolo-gous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes.

Results: 71 patients with a mean age of 33 years (15–48) were randomised to undergo either an ACI-C or a MACI. 37 had ACI-C and 34 MACI. The mean size of the defect was 5.0cm2. Mean duration of symptoms was 104.4 months (9–456). Mean follow-up was 33.5 months (24–45). Functional assessment using the modified Cincinnati knee score, the Bentley functional rating score and the visual analogue score was carried out. Assessment using the modified Cincinnati knee score showed a good to excellent result in 57.1% of patients followed up at 2 years, and 65.2% at 3 years in the ACI-C group; and 63.6% of patients at 2 years, and 64% at 3 years in the MACI group. Arthroscopic assessments showed a good to excellent International Cartilage Repair Society score in 81.8% of ACI-C grafts (22 patients) and 50% of MACI grafts (6 patients). Fisher’s exact test showed a p value of p=0.35 (not statistically significant). Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in biopsies of 56.3% of the ACI-C grafts (9 out of 16 patients) and 30% of the MACI grafts (3 out of 10 patients) after 2 years. Fisher’s exact test showed a p value of p=0.25 (not statistically significant).

Conclusion: At this stage of the trial we conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI.

Introduction: The load bearing status of articular cartilage has been shown to affect its biochemical composition. This study investigates the topographical variation of glycosaminoglycan (GAG) relative to DNA content in human distal femoral articular cartilage.

Methods: 26-paired specimens of distal femoral articular cartilage, from weight bearing and non-weight regions, were obtained from thirteen patients undergoing amputation. Following papain enzyme digestion, spectropho-tometric (GAG) and fluorometric (DNA) assays assessed the biochemical composition of the explants. Data was analysed using a paired T test.

Results: Despite no significant differences in absolute DNA concentrations, weight-bearing regions of articular cartilage showed a significantly higher concentration of GAG relative to DNA compared with non-weight bearing areas (p=0.021).

Discussion: This study suggests that chondrocytes in weight bearing regions of human articular cartilage produce a greater quantity of GAG than those located in non-weight bearing areas. We conclude that mechanical loading is essential in maintaining the biochemical composition of human articular cartilage.

Aim: To study the remodelling of cortical bone around the passive growing component of an expandable endoprosthesis.

Introduction: When inserting the passive component of an expandable prosthesis a polyethylene sleeve is commonly used. The sleeve migrates towards the lateral cortex and causes a cortical reaction and hence the use of the sleeve has been discarded recently. This study quantifies the amount of cortical reaction and degree of cortical drift in patients that had sleeves and those that did not.

Material And Methods: We reviewed X-rays and case notes of all patients that had an expandable endoprosthesis in a 20 year period. The thickness of medial and lateral cortices of the tibial diaphysis was measured at 6 months and on the last follow up radiograph. The distance from the edge of the sleeve (or prosthesis) from the cortical edge was also compared. Retrieved components also had their histology reviewed.

Results: The sleeve shifted laterally on average by 2mm (range 0.5 – 3mm) and touched the cortex. This was associated with an increase in lateral cortical thickness by 2.27mm (range 1 – 3mm). When the sleeve was used the prosthesis was inserted in the mid-line. When the sleeve was not used the tibial component tended to be inserted in valgus.

Conclusions: The presence of a sleeve is associated with a cortical reaction and the sleeve tends to migrate laterally. The clinical implications of this and the evolution of the design will be discussed in the meeting.

Purpose: To report the importance of early diagnosis, adequate surgical margin and postoperative radiotherapy for optimum outcome and survival.

Study Design: A retrospective review of 46 sacral chordoma patients treated between 1987 and 2004.

Methods: There were 33 male and 13 female patients, with mean age of 61 years (38 to 73 year). The surgical approach depended on the level and extent of the lesion, with an anteroposterior approach used in 23 and posterior approach in 17 patients. 20 had partial sacrectomy, 17 had subtotal sacrectomy and 3 underwent total sacrectomy. 6 patients were deemed inoperable and received palliative therapy. 14 patients received radiotherapy postoperatively. The length of average follow up was 4.27 years (range 2–15.7 years).

Results: Low back pain was the most common presenting symptom (80%), and 50% patients had a palpable mass. The mean duration of symptoms prior to diagnosis was 2 years (range 1 month–10 years). Examination revealed a palpable mass in 7 both externally and on rectal examination. 10 had palpable mass on rectal examination but not externally. 2 patients presented with multiple metastases and another 2 with widespread local disease.

Excision was complete in 23 patients and incomplete in 17. Histology revealed dedifferentiation in 4. Complete excision margin was achieved in 69.6% through combined approach and 52.9% through posterior approach only. 24 patients (52%) had local recurrence. Without adjuvant radiotherapy the mean disease-free period following complete excision was 3.5 years, compared to 0.9 years following incomplete excision. Adjuvant radiotherapy extended the mean disease-free period following incomplete excision to 1.8 years.

Conclusion: An early diagnosis and careful examination is important. Wide excision remains the mainstay of treatment. If excision is incomplete radiotherapy increases the disease free period although local recurrence is inevitable. Use of combined approach increases the likelihood of complete excision.

Aim: The aim of this study was to correlate the histology of cartilage repair site with long term clinical function.

Materials and methods: We have analyzed the clinical results of a cohort of patients who had collagen-covered autologous chondrocyte implantations performed since 1998. Our hypothesis was that the hyaline cartilage repair does influence the clinical outcome.

The modified Cincinnati scores (MCRS) of eighty-six patients were evaluated prospectively at one year and at the latest follow-up following ACI-C (mean follow-up= 4.7 years. Range= 4 to 7 years). All these patients underwent biopsies of their cartilage repair site performed at variable periods between six months and five years following ACI-C (mean=22.2 months). The neo-cartilage was graded as hyaline (n=32), mixed fibrohyaline (n=19), fibrocartilagenous (n=35) and fibrous (n=0).

Results: The clinical results showed that at one year, the percentage of patients with excellent and good results was 84.4, 89.5 and 74.3 respectively for those with hyaline, mixed fibro-hyaline and fibro-cartilagenous histology respectively. Their mean MCRS were 70.8, 72.4 and 66.2 respectively. This difference was not statistically significant (p=0.34).

However, their clinical scores at the latest follow-up demonstrated a significantly superior result for those with hyaline repair tissue when compared to those with mixed fibro-hyaline and fibro-cartilagenous repair tissue (p=0.05). The percentage of patients with excellent and good results for those with hyaline, mixed fibro-hyaline and fibro-cartilagenous repair was 75, 42 and 68.6 respectively. Their mean MCRS were 70.6, 56.8 and 63.9 respectively.

Conclusion: This study demonstrates that any form of cartilage repair would give good clinical outcome at one year. At four years and beyond, it appears that patients with hyaline repair tissue tend to show a more favourable clinical outcome whereas those who demonstrated mixed fibrohyaline and fibrocartilagenous repair would show less favourable clinical results.

Purpose: We report a series of 58 patients with metastatic bone disease treated with resection and endoprosthetic reconstruction over a 5 year period at our institution.

Introduction: The recent advances in adjuvant and neo-adjuvant therapy in cancer treatment has resulted in improved prognosis of patients with bone metastases. Most patients who have an actual or impending pathological fracture should have operative stabilisation or reconstruction. According to BOA guidelines patients should undergo a single procedure which allows early full weight bearing and lasts the expected lifespan of the patient. The use of modern modular endoprostheses allows these criteria to be met.

Methods and Results: We retrospectively identified all patients diagnosed with metastatic disease to bone between 1999 to 2003. 171 patients were diagnosed with bone metastases. Metastatic breast and renal cancer accounted for 47% of the lesions. 58 patients with bone metastasis to the appendicular skeleton had an endo-prosthetic reconstruction. There were 28 males and 30 females. 11 patients had lesions in the upper extremity and 47 patients had lesions in the lower extremity. Mean age at presentation was 62 years (24 to 88 years). 19 patients are still alive, 34 patients had died and 5 were lost to follow-up. Patients died of disease at a mean of 22 months (2 to 51 months) from surgery. Mean follow-up was 55 months (24 to 78 months). There were 5 wound infections, 1 aseptic loosening, 3 dislocations, 1 subluxation and 1 prosthesis rotated requiring open repositioning. Patients were followed up and evaluated using the Musculoskeletal Society Tumour Score (MSTS) and the Toronto Extremity Salvage Score. The mean MSTS score was 73% (57 to 90%) and TESS was 71% (84 to 95%).

Conclusions: We conclude that endoprosthetic replacement for the treatment of bone metastases in selected cases achieves the aims of restoring function, allowing early weight bearing and alleviating pain. The complication rate is low.

Introduction: Since 1975, 6 types of extendable endo-prostheses have been developed at Biomedical Engineering, UCL, and Stanmore Implants Worldwide in conjunction with the surgeons at this centre.

Aims: To establish whether developments in design have had the desired effect of improving both implant survivorship and functional outcome.

Methods: This was a retrospective study using case notes, hospital databases and a radiological review, combined with contemporary functional outcome assessments (MSTS, TESS, SF36).

Results: 161 consecutive prostheses in 138 paediatric patients, between the years of 1983 – 2005, were implanted for primary bone tumours. Mean age was 10.3 (3 – 18), 81 were males and 57 females. There were 136 primary procedures and 25 revisions.

6 prostheses that used ball bearings to achieve length (designed in 1981) were implanted, 3 (50 %) were revised due to mechanical failure.

19 prostheses that utilised external C-washes (1998) to achieve length were implanted, 6 (32 %) were revised, half of these for mechanical failure.

Of the 98 minimally invasive prostheses (1992) that utilized an Allan key and screw-jack mechanism to lengthen, 14 (14 %) were revised, half of these for infection.

17 non-invasive extendable endoprostheses (2001) that are lengthened by electromagnetic coupling have been implanted so far. There has only been 1 (6 %) revision. This was due to full extension being reached.

Conclusions: Design improvements in growing endoprostheses since 1983 have led to improved survivorship. Initially this led to a reduction in mechanical failure and latterly to a reduction in infection, as indications for revision.

Key Words: Bone tumour, children, endoprosthesis, survivorship.

Purpose: We report a series of patients with malignant tumours of the pelvis that had a tissue expander inserted in the pelvis to facilitate radical radiotherapy, and report functional outcomes following treatment.

Introduction: Surgery for malignant tumours affecting the pelvis is challenging. Some tumours are suitable for internal hemipelvectomy and reconstruction, some require hindquarter amputation and some are inoperable. Overall prognosis is poor with high morbidity and mortality rates. There may be a place for alternative treatment with the insertion of pelvic spacers to facilitate radical radiotherapy. This is indicated in patients who have an inoperable tumour, who decline amputation, or who had an internal hemipelvectomy with close margins and high risk of local recurrence.

Methods & Results: We performed a retrospective review of all patients who presented with a malignant tumour of the pelvis and who underwent an insertion of a pelvic spacer followed by local high dose radiotherapy. Available patients were followed up and evaluated using the Musculoskeletal Society Tumour Score (MSTS) and the Toronto Extremity Salvage Score (TESS). There were ten patients; 5 had Ewing’s sarcoma, 3 had osteosarcoma, 1 had spindle cell sarcoma and 1 had alveolar soft part sarcoma. 4 patients had metastases on presentation. The average age was 30 years (14 to 56 years), and average follow-up was 15 months (12 to 24 months). 4 patients died and 6 are still alive. There were no surgical complications. The average length of hospital stay was 6 days (2 to 10 days). Patients averaged an MSTS score of 63% and a TESS of 67%.

Conclusion: Radical radiotherapy after spacer insertion offers an alternative to morbid surgery and is associated with good functional outcomes.

Introduction and Aims: Allogenic blood transfusion is often required in lower-limb arthroplasty. The aims of this study were (1) to analyze the influence of anaemia on post-operative fatigue, hand grip strength, duration of in-patient physiotherapy and post-operative morbidity score (POMS) and (2) to investigate for prognostic factors to predict functional recovery following primary arthroplasty of the lower limb.

Patients and methods: This study was approved by the regional ethics committee. Two hundred patients (88 THR, 99 TKR and 13 hip resurfacing) were evaluated in this prospective trial. Blood haemoglobin concentration (Hb), hand grip strength and vigour scores using a validated fatigue questionnaire were estimated both preoperatively and at 3 days following surgery. Postoperative morbidity score (POMS) and the required duration of in-patient physiotherapy were also noted. The protocol for blood transfusion was for those with Hb less than 8 g/dL and/or post-operative symptoms attributable to anaemia.

Results: A greater fall in postoperative Hb correlated significantly with a greater reduction in post-operative vigour score (p=0.02). Also a greater fall in vigour score was found to correlate significantly with the duration of in-patient physiotherapy (p< 0.001). A reduction in Hb of > 4g/dL from the pre-operative Hb predicted a significantly higher reduction in vigour score (p=0.03). A weak correlation was seen between a fall in Hb and POMS (p=0.09).

A higher pre-operative Hb did not reduce the required duration of in-patient physiotherapy (p=0.72). There was no correlation between post-operative Hb and POMS (p=0.21) or required duration of in-patient physiotherapy (p=0.20).

A higher pre-operative grip strength predicted an early date of discharge by the physiotherapists (p=0.02).

Conclusion: We conclude that a fall in Hb of more than 4 g/dL has a detrimental effect on post-operative rehabilitation. Pre-operative grip strength measurements are valuable in predicting the rehabilitation potential of patients undergoing lower limb arthroplasty.

Introduction: Predicting outcomes in the heterogenous population undergoing Total Knee Arthroplasty (TKA) is difficult. This prospective multi-centre study details the relationship between preoperative knee function and the sequential clinical and functional outcome progression of TKA.

Methods: Annual clinical and functional outcome scores (Oxford Knee Score & Knee Society Score) from 526 primary cemented Kinemax TKA implanted into 506 patients over a period of 3 years were assessed. Depending on preoperative knee function, patients were grouped into 3 cohorts: mild, moderate and severe.

Results: At one year there was a significantly (p< 0.05) greater improvement in Oxford Knee Score, Knee Society Score and range of movement in patients with severe preoperative knee function in comparison to the mild cohort. However, a significantly greater improvement (p< 0.05) in functional outcome was shown in patients with mild preoperative knee function.

Only patients with severe preoperative knee function showed deterioration in outcome measures from three years, all other patients maintained improvements.

Discussion: Severe, in comparison to mild, preoperative knee function predicts greater clinical but inferior functional improvement at one year, with deterioration in all outcome measures commencing from three years. Mild to moderate preoperative knee function affords ongoing sequential improvement in clinical and functional outcomes.

Introduction: The treatment of distal femoral cartilage defects using autologous chondrocyte implantation (ACI) and matrix-guided autologous chondrocyte implantation (MACI) is become increasingly common. This prospective 7-year study reviews and compares the clinical outcome of ACI and MACI.

Methods: We present the clinical outcomes of 159 knees (156 patients) that have undergone autologous chondrocyte implantation from July 1998. One surgeon performed all operations with patients subsequently assessed on a yearly basis using 7 independent validated clinical, functional & satisfaction rating scores.

Results: Modified Cincinnati, Patient Functional Outcome and Lysholm & Gilchrist clinical rating scores all showed significant improvements compared to pre-operative levels (p< 0.0001). Although ACI scores are superior at one year (p< 0.05) there is no significant difference between ACI and MACI at 2 years.

Visual Analogue Score and Bentley Functional rating score showed significant improvements compared to pre-operative levels (p< 0.0001) with ongoing yearly sequential improvement.

Patient Rating and Brittberg scores, both subjective patient scores, similarly showed continuing improvements in the years following surgery.

Discussion: ACI and MACI produce significant improvements in knee function when compared to pre-operative levels with continued sequential improvement in outcomes for up to seven years. The initial data suggests a superior rate of clinical improvement using the MACI technique

Background: Extra-compartmental limb soft tissue sarcomas are notoriously difficult to treat. These tumours can exhibit macro or microscopic spread beyond the confines of normal anatomical barriers and require radical resection, often necessitating excision of bone as well as soft tissue. This will inevitably affect the patient’s functional outcome. The primary operations for these aggressive sarcomas include wide local excision of soft tissue and adjacent involved bone, radical resection with endoprosthetic reconstruction and amputation.

Methods: 85 patients who underwent such an operation between 1995 to 2000 were reviewed and categorised according to whether they received wide local excision, endoprosthesis reconstruction or amputation. Patient demographics, sarcoma details, recurrence and survival rates were identified and compared between the three groups. Functional outcomes in the 45 patients still alive were assessed using TESS and MSTS scores.

Results: Mean age was 61 years (range 8 to 92). There were 51 males and 34 females. Anatomical distribution was as follows: arm 26, leg 47, pelvis 8 and other 4. The commonest histology subtypes were MFH, leiomyosarcoma and undifferentiated soft tissue sarcoma. 17 had wide local excision of bone and soft tissue, 32 underwent endoprosthesis reconstruction and 36 underwent primary amputation. Recurrence rates were highest in the endoprosthesis group at 19%. Five year survival was worst in the amputation group at 49%. Functional outcomes were highest in the wide local excision group, and similar in the other two surgical groups.

Conclusions: Unsurprisingly survival is poorest in the primary amputee group because of the highly aggressive nature of these sarcomas, despite having the most radical treatment. The similar functional outcomes shown between endoprosthesis reconstruction and primary amputation may be influential when considering cases in which this decision is unclear and function is the main issue at stake.

Background: Metal-on-Metal (MoM) hip bearings are being implanted in ever increasing numbers and into ever-younger patients. The consequence of chronic exposure to metal ions is a cause for concern. Therefore, by using cytogenetic biomarkers, we investigated a group of patients who have had MoM bearings in-situ for in excess of 30 years.

Method: Whole blood specimens were obtained from an historical group of patients who have had MoM bearings in-situ for in excess of 30 years. Blood was also obtained from an age and sex matched control group and from patients with Metal-on-Polyethylene (MoP) components of the same era.

The whole blood was cultured with Pb-Max karyotyping medium and harvested for cytogenetics after 72 h. The 24 colour FISH (Fluorescent In Situ Hybridisation) chromosome painting technique was performed on the freshly prepared slides allowing chromosomal mapping. Each slide was evaluated for chromosomal aberrations (deletions, fragments and translocations) against the normal 46 (22 pairs and two sex) chromosomes. At least 20 metaphases per sample were scored and the number of Aberrations per cell calculated.

Results: Chromosomal aberrations, including deletions, fragments and translocations were only detected in the peripheral blood lymphocytes isolated from the group that had MoM bearings. These changes were not present in the age and sex matched control group. The chromosomal aberrations were also detected in the patients previously exposed to MoM bearings who have been revised to a MoP articulation.

Conclusion: We have detected dramatic chromosomal aberrations in peripheral blood lymphocytes in a group of patients chronically exposed (over 30 years) to elevated metal ions. It is not known whether these aberrations have clinical consequences or whether they are reproduced in other cells in the body. The results emphasise the need for further investigations into the effect of chronic exposure to elevated metal ions produced by Orthopaedic implants.

Purpose: We report the clinical and functional outcome of limb salvage surgery and endoprosthetic reconstruction of the distal tibia and ankle joint in 5 patients.

Introduction: The distal tibia is an uncommon site for primary malignant bone tumours and the treatment of choice for most patients is a below knee amputation. Patients who decline an amputation may be offered an endoprosthetic replacement. This is a technically challenging operation and may be associated with high morbidity.

Methods and Results: Over 25 years at our centre, 5 patients underwent distal tibial replacements for bone or soft tissue sarcomas. Two had osteosarcoma, one had a recurrence of Ewing’s sarcoma, one had malignant fibrous histiocytoma, and one had an adamantinoma. The mean age was 37 years (13 to 69 years). There were no tumour recurrences. Four patients developed complications with wound infection. Two of these resulted in below knee amputations. Average follow-up was 31 months (19 to 55 months) with 1 patient lost to follow-up. Patients were evaluated using the Toronto Extremity Salvage Score (TESS) and the Musculoskeletal Tumour Society (MSTS) score. The mean MSTS score was 88% and the mean TESS was 88.5%. Two patients who later had a below knee amputation and who were using a prosthesis averaged an MSTS score of 86.3% and a TESS of 89.3%.

Conclusion: For those patients who are unwilling to undergo an amputation for malignant tumours of the distal tibia, endoprosthetic reconstruction is an alternative, but at the cost of increased risk of significant complications, functional deterioration and morbidity. There was little difference between functional scores for patients who proceeded to have a below knee amputation compared to patients who still had their endoprosthesis

Bone grafts are frequently used to augment bone healing. Autologous bone graft is the gold standard for osteogenesis but is limited by availability and donor site morbidity. The processing required to lower the immunogenicity of allograft also reduces the osteogeneic properties. Bone marrow contains mesenchymal stem cells (MSCs) which differentiate into osteoblasts, forming bone. Our study examined the use of bone marrow to enhance the osteogenic properties of allograft.

Bioactive proteins within allogenic bone graft stimulate marrow-derived MSCs to differentiate into osteoblasts, thereby increasing the osteogenic nature of the graft.

After informed consent, bone marrow aspirates were taken from five patients during orthopaedic operations. Freeze-dried ethylene oxide treated allograft, from a number of donors, was obtained from the bone bank. MSCs isolated from each marrow aspirate were grown on eight samples of test allograft. Further allograft was heated to 70°C to denature the osteogenic proteins and MSCs from each aspirate were grown on 8 samples, as a negative control. Osteoblastic differentiation of MSCs cultured on the types of allograft was compared.

Scanning electron microscopy confirmed that MSCs covered the allograft after 14 days. Transmission electron microscopy showed that cells on the test allograft were characteristic of osteoblasts and produced collagen extracellular matrix. The levels of osteoblastic proteins, ALP, osteopontin and Type I pro-collagen, produced by cells on test allograft were significantly greater compared with heat-treated control (P< 0.005), after days 7 and 14.

Our study showed that marrow-isolated MSCs could be successfully cultured on allograft. As the levels of osteoblastic proteins increased significantly when MSCs were grown on allograft, osteogenic proteins within allograft caused MSCs to change into osteoblasts. This confirms that autologous marrow MSCs could be grown on allograft to increase its osteogenic prior to grafting, resulting in increased rate of bony healing.

Endoprosthetic reconstruction as a form of limb salvage in the management of malignant disease is common. We present our experience with custom-made distal femoral replacement as a form of limb salvage in the absence of malignancy.

49 cases of distal femoral replacement were identified using the unit database. There were 18 males and 31 females, with a mean age at operation of 62.3 years (range 26–86). There were 29 cases of failed total knee replacements, 8 cases of fracture associated with bone loss, non-union or deformity, 7 periprosthetic fractures, 3 aneurysmal bone cysts, and one case each of avascular necrosis and Gorham’s disease. Clinical and radiographic review of all available patients, including a functional assessment with the Musculoskeletal Tumour Society (MSTS) Score and Toronto Extremity Salvage (TES) score was undertaken.

The average follow-up was 5.4 years (range 1 to 29 years). Three types of endoprosthesis were used, rotating hinge, fixed hinge and arthrodesis prosthesis. One patient required amputation at 2 months following post-operative wound infection with methicillin-resistant staphylococcus aureus and subsequent inability to provide adequate soft tissue coverage. There was one revision at 16 months for deep prosthetic infection. 21 patients were available for functional follow-up. The mean MSTS score was 63.7 (range 16.0–86.7) and the mean TES score was 59.4 (range 9.4–87.5).

Custom-made distal femoral replacements have an established role in limb-salvage surgery for malignant disease. This series demonstrates the reconstructive capability of custom prostheses in non-malignant disease, where deformity causes functional embarrassment or when massive bone loss would normally lead to amputation.

The purpose of this study was to determine whether the low rate of mechanical loosening of the SMILES rotating hinge distal femoral endoprosthesis relates to the hydroxyapatite (HA)-coated, grooved collar of the femoral component.

A database was used to identify two groups of cases of primary distal femoral replacement with a custom-designed and manufactured SMILES endoprosthesis at our unit; those with the collared femoral component (“collar group”), and those without a collar (“non-collargroup”). From these two groups, patients were pair-matched for age and length of bone resection. A retrospective review of serial biplanar pairs of radiographs of each patient, assessing radiolucent lines and extracortical bone pedicle.

11 matched pairs were identified, (14 females, 8 males), with a mean age of 36 years, (range 16–66). The pathology was primary bone tumour in 20 cases, (17 malignant, 3 benign), and metastatic disease in 2 cases. Mean length of follow-up was 85 months, (range 27–122). Radiolucent line score (RLS) progression over time was significantly lower in the collar group, (0.01 vs 0.73, p=0.001) (fig. 1 & 2), as was the mean final RLS, (2.72 vs 7.81, p=0.02). Mean RLS per radiographic quadrant was 0.56 in cases in which a bony pedicle was ingrown onto the prosthesis, (exclusively in the collared-group), 2.41 in cases in which the pedicle was not ingrown, (most prevalent in the non-collared group), and 1.02 in those cases without any pedicle formation, (ANOVA analysis, p=0.0002).

This study demonstrates that the HA-coated, grooved collar significantly reduces the progression of radiolucent lines, and consequently the overall RLS, explaining the reduced rate of mechanical loosening of the collared endoprosthesis. A bony pedicle that does not incorporate onto the prosthesis surface may be associated with an increase in radiographic loosening.

The aim of this study was to compare the accuracy of image guided (ultrasound or CT) percutaneous needle biopsy to percutaneous needle biopsy without image guidance in diagnosis of soft tissue tumours.

Eighty-eight consecutive patients with soft tissue lesion who were referred to the soft tissue tumour unit underwent percutaneous needle biopsies of their lesion either with image guidance or without. Sixty-one out of these 88 patients subsequently underwent excision of their lesion and the excised specimen was then subjected to histological examination. The accuracy of image guided percutaneous needle biopsy and percutaneous needle biopsy without image was then calculated by comparing the histological results of the needle biopsy to that of excision biopsy.

The diagnosis accuracy of image guided percutaneous needle biopsy was 92% (34 out 37) compared to 79% (22 out of 28) for percutaneous needle biopsy without image. In 3 out of the 28 patients who had percutaneous needle biopsy without image guidance, there was insufficient material obtained from the needle biopsy to allow a histological diagnosis. This was not the case with any of the patients who had image guided percutaneous needle biopsy.

Conclusion: Using image guidance, either USS or CT scan, improves the diagnostic accuracy of percutaneous needle biopsy and should be the gold standard technique in management of soft tissue tumours. However, if the lesion is palpable and not mobile, the accuracy of percutaneous needle biopsy without image guidance can be up to 79%.

This prospective study analyses the histological results of autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint. Chondrocytes from a non-weight bearing area of the knee were harvested and then cultured in vitro.

Re-implantation involved injection of the chondrocytes into the defect, which was then sealed with a collagen membrane. One year post-op, patients were evaluated by clinical, arthroscopic and histological assessment. A biopsy of the transplanted region was examined by staining with Erlich’s H& E and Safranin 0, polarised light microscopy and by analysis with S100 and immunohistochemistry. Hyaline cartilage content was further assessed by examination of Type IIa & lIb collagen mRNA expression using in-situ hybridisation.

The median age was 31 years. 63 knees were treated. Solitary lesions were treated in 61 knees with two defects being treated in three knees (66 defects in total). The defects were located on the medial femoral condyle in 39 cases, lateral femoral condyle in 14, trochlea in 2 and patella in 11. The defect size ranged from 1–7 cm2 (mean area 3cm2 ). 40 patients had at least one-year follow-up. Using the Brittberg Rating, 11 had excellent results, with 15 good, 10 fair and 4 poor. The mean Lysholm and Gillquist scores improved from 44 pre-op to 77 one-year post-op. Biopsy at one year conftrmed the presence of hyaline cartilage in 22 out of 32 cases (69%). In-situ hybridisation confirmed the presence of Collagen type II in the deep zones of the biopsy with a fibrocartilaginous appearance superficially.

Conclusion: This technique can provide an effective treatment for cartilage defects. The histological results are encouraging and chondrocyte transplantation may be the only procedure to allow regeneration of hyaline like articular cartilage.

The purpose of this study was to evaluate the results of custom-made endoprosthetic reconstruction for both tumourous and non-tumourous conditions around the elbow joint.

28 consecutive cases of endoprosthetic elbow reconstruction, performed between 1989 and 2003, were identified using the unit database. There were 12 males and 16 females, with a mean age 48.9 years, (range 14–84). There were 16 cases of malignant tumour (10 primary, 6 secondary), 3 cases of benign tumour (one each of giant cell tumour, osteoblastoma and pigmented villonodular synovitis) and 10 non-oncological cases, (5 cases of fracture, 3 failed total elbow replacements and 1 infected synostosis). A distal humeral prosthesis was used in 16 patients, distal humeral and proximal ulna in 10 patients, proximal ulna with a humeral component in one patient and proximal radial replacement in one patient. Clinical and radiographic review of all available patients, including a functional assessment with The Toronto Extremity Salvage score (TESS) was undertaken.

28 consecutive cases of endoprosthetic elbow reconstruction, performed between 1989 and 2003, were identified using the unit database. There were 12 males and 16 females, with a mean age 48.9 years, (range 14–84). There were 16 cases of malignant tumour (10 primary, 6 secondary), 3 cases of benign tumour (one each of giant cell tumour, osteoblastoma and pigmented villonodular synovitis) and 10 non-oncological cases, (5 cases of fracture, 3 failed total elbow replacements and 1 infected synostosis). A distal humeral prosthesis was used in 16 patients, distal humeral and proximal ulna in 10 patients, proximal ulna with a humeral component in one patient and proximal radial replacement in one patient. Clinical and radiographic review of all available patients, including a functional assessment with The Toronto Extremity Salvage score (TESS) was undertaken.

Endoprosthetic reconstruction around the elbow joint is effective in a wide range of pathologies, allowing in most cases a reasonable level of function, even following two-stage revision for infection.

Introduction: Surgeons in the UK and Europe generally use a thinner cement mantle than their counterparts in the USA for the femoral component in total hip replacement (THR). The aim of this study was to compare the performance of different thicknesses of cement mantle using finite element analysis. The measures by which comparison might be made include cement cracking, subsidence, migration and stress shielding. In this study, we use a linear-elastic model of the implanted femur to give a prediction of the stresses in the cement mantle and in the femoral cortex. These measures give an indication of the relative rates of cement cracking and loss of bone stock due to stress shielding. To assess the reliability of our model in representing patients with different bone densities, we use a range of cancellous bone stiffnesses.

Method: Two cadaveric femora from the same donor were sized, reamed and implanted with identical plastic replica femoral components following standard surgical technique for the Stanmore Hip system. One was prepared using UK rasps, over-reaming by ~2mm, the other using US rasps, over-reaming by ~5mm. Serial CT-scans were used to create three-dimensional geometric models of the implanted femora. Two finite element meshes were hand-built in MSC. Marc finite element software, incorporating cortical and cancellous bone, bone cement and prosthesis. Each model consisted of 10,000 eight-noded brick elements, with a fully bonded stem-cement interface. The thick and thin cement mantles had thicknesses of 2.5mm and 1.0mm respectively, in regions where thickness is affected by rasp size. Models were identical in the distal medullary canal. Cortical bone was modelled as transversely isotropic, with longitudinal and transverse moduli of 17.0 and 11.5 GPa. Bone cement was given a modulus of 2.7 GPa. Loading conditions were chosen to represent the heel-strike phase of gait. In order to assess the impact of variability in patient bone density, cancellous bone modulus was varied between 0.06 and 2.90 GPa.

Results: Equivalent stress was examined on the external surface of the cortex and the internal surface of the cement mantle. The lowest cortical bone stresses were proximal and the highest cement stresses around the distal tip of the prosthesis. In the proximal cortex, higher equivalent stresses were observed medially and laterally with a thick cement mantle. Distally, lower cement stresses were observed in the thick cement mantle. With the highest cancellous modulus, there was little difference between the two models. As this modulus was reduced, stress differences between the models became more apparent. For all cancellous bone moduli, peak distal cement stresses were lower and minimum proximal calcar stresses higher in the thick cement mantle.

Discussion: Proximal stress shielding was greatest in the calcar, in agreement with clinical findings. The thicker cement mantle led to less stress shielding in this region. Cement stresses, highest around the distal tip of the prosthesis, were larger in the thin cement mantle. This suggests a higher rate of both cracking and bone resorption in thin cement mantles. Although observed over a range of cancellous bone stiffness, this finding applies particularly to patients with low bone density.

Introduction: Aseptic loosening remains the commonest causes of failure of total hip arthroplasty. Cement mantle defects are associated with aseptic loosening. This study aimed to determine a correlation between surgical approach and cement mantle defects in the Stanmore Hip. The Stanmore total hip replacement was chosen because it has greater than an eighty-five percent survivorship over 25 years and unlike other prostheses with comparable results such as the Charnley total hip, it remains essentially unchanged to date.

Method: This was a retrospective review of all Stanmore hips. AP and lateral radiographs were available for 62 patients operated via the posterior approach and 100 patients operated via the anterolateral approach. The mean cement thickness in all fourteen Gruen zones was estimated for each patient. Gruen zones IV and XI, representing the stem tip, were removed from data relating to mantle thickness. Mantles were graded as less than 2mm, 2–5mm, 5–10mm and more than 10mm. Alignment was also measured.

Results: Fifty-nine percent (32/54) of cement mantle defects are seen in Gruen zones VIII to XIV. The mean cement mantle thickness in A-L approach was 3.11mm compared to 4.23mm with the posterior approach. This corresponds with the frequency of cement mantle defects occurrence. No cement defects were seen in Gruen zones IV or XI. Using the anterolateral approach, defects were observed in 49 out of 1200 zones (4.08%) and using the posterior approach in 6 out of 744 zones (0.81%). With the anterolateral approach, 19 out of 100 cement mantles (19%) had defects, compared to only 3 out of 62 (4.84%) with the posterior approach. Defects were most commonly seen in zones I, V, VIII and XII, which corresponds to valgus and posterior orientation of the stem.

Discussion: The posterior approach does generate a more uniform cement mantle. Several studies suggest that a cement mantle smaller than 2mm or greater than 10mm can be detrimental to the survivorship of the arthroplasty. This study suggests that a deficient cement mantle is more likely using an anterolateral approach.

Introduction A consensus exists regarding the optimal range of femoral cement mantle thickness in hip replacement. However, within this range surgical preferences differ, surgeons in Europe generally preferring thinner cement mantles whilst those in the US prefer a thicker mantle. For a given implant size, the rasps provided in the US for use with the Stanmore Hip are larger than those used in Europe, producing a thicker cement mantle. The integrity of the femoral cement is considered to be crucial to the long-term survival of cemented hip replacements. Previous studies have used cement cracking under fatigue loading as a comparative measure of implant survival. Damage accumulation levels between different implants are associated with clinical failure rates. The aim of this study was to compare the cracking behaviour of cement mantles of different thicknesses around Stanmore Hip replacements. We hypothesised that a thicker cement mantle would lead to reduced cement cracking.

Methods Ten synthetic femurs (Sawbones) were prepared following standard surgical practice for the Stan-more Hip. Five of these were rasped using the larger US rasp, and five using the European version. Stanmore Hip femoral components were then cemented into the femurs with Palacos-R cement and using a custom insertion rig to ensure good alignment and centralisation, confirmed by radiographs. The femurs were then cyclically loaded with an aggressive 4 kN stair-climbing load for 4 million cycles at 3 Hz. The femurs were sectioned at 5 mm intervals and dye penetrant used to highlight cement cracks. Image analysis software was used to measure cement thickness and crack lengths under light microscopy.

Results The minimum cement mantle thickness per section was found to average 0.8 mm and 2.0 mm for the thin and thick mantle groups respectively, measured around the proximal half of the implant. This was significantly different (p< 0.05). Cracks in the cement mantle were irregularly distributed along the length of the prostheses. We found no significant difference in either the total number or total length of cracks found in each group. These were investigated over the whole mantle and by Gruen Zone.

Discussion The geometric and mechanical properties of human femurs vary considerably, which might be expected to increase dramatically the scatter in any clinical trend relating cement thickness to cracking. Our study, using identical synthetic femurs and well-centralised prostheses to minimise experimental variability, found no difference in cracking. Given this experimental consistency, it is thought that there would be no clinically significant difference in cracking rates between different cement thicknesses within the normal range for the Stanmore Hip replacement. The Stanmore Hip is designed to minimise cement stress. A collar prevents subsidence-related hoop stresses, and smooth corners minimise stress concentration in the cement. It is likely that, for a sub-optimal implant design with higher stress risers, cement thickness might have a more noticeable effect on crack propagation.

Introduction: Mazabraud syndrome is a rare disorder characterised by fibrous dysplasia and intramuscular myxomas. We present six new cases.

Method: A reterospective review was performed on six patients from our institution. This is a consecutive series over 48 months.

Results: The patient group consisted of three females and three males. The six patients were referred to our bone tumour unit from other hospitals (four by orthopaedic teams and two by general surgeons). The referring hospitals had been unable to exclude a malignant process. Imaging was tailored to each individual case. Three of our six patients demonstrated polyostotic fibrous dysplasia. The commonest site of the osseous leision was the proximal femur (n=4). The majority of the patients had solitary myxomas (n=4) with only two being multiple myxomas. The average size of the myxomas was 3.7 cm. All soft tissue leisions were ipsilateral to the osseous leisions.

Five of the six patients were treated with surgical excision.

Discussion: In contrast to the existing literature the majority(n=4) of the six patients had solitary myxomas and the male to female distribution was equal. One of the cases was also unique to the current literature with the syndrome present in the right elbow.

The number of cases that we have seen in a short time may also be an indication that this syndrome is not as rare as scarcity of the published cases would imply.

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.

Soft tissue balance is known to be an important factor for the success of Total Knee Arthroplasty (TKA). Traditional surgical techniques involve soft tissue releases and bony cuts to achieve the correct balance. Evaluation of balance is currently based on subjective intraoperative clinical assessment, or the “feel” of the knee. More recently, an instrument to objectively measure soft tissue balance following bony cuts has been developed. Soft tissues releases using this instrument may be extensive.

Hypothesis. The hypothesis is that patients who undergo more extensive releases will have poorer short-term outcome and increased complication rates compared to those who undergo less extensive releases.

Method: 506 patients aged 40–90 years underwent 526 Kinemax TKAs, performed by seven surgeons in five centres between October 1999 and December 2002. Five surgeons used traditional methods for soft tissue balancing and two were guided by the balancer instrument taking measurements pre- and post-releases. Patients were assessed by an independent observer using the Oxford Knee Score, the American Knee Society Score and radiographic evaluation, with a minimum follow-up of 12 months.

Results: Extensive soft tissue releasing procedures showed no significant difference in outcome in comparison with minimal releases. For the 2 surgeons using the ‘balancer’ technique, a significant difference was seen with the change in knee scores. The knees left imbalanced had substantially lower change scores and the imbalanced – balanced group showed the most improvement. There was no significant difference between surgical technique or range-of-movement with outcome. Complication rates were low, clinically representative and showed no significant difference between the groups.

Conclusions: Extensive soft tissue releases do not result in an increase in complication rate or a poorer short-term outcome. When comparing traditional and ‘balancer’ guided techniques there is no difference in outcomes. Balancing an imbalanced knee significantly improves knee outcome.

Introduction: Surgeons in the UK and Europe generally use a thinner cement mantle than their counterparts in the USA for the femoral component in total hip replacement. The aim of this study was to compare the performance of different thicknesses of cement mantle using finite element analysis. A linear-elastic model of the implanted femur is used to give a prediction of the stresses in the cement mantle and in the femoral cortex. These measures give an indication of cement cracking rates and stress shielding. To assess the reliability of our model in representing patients with different bone densities, we use a range of cancellous bone stiffnesses.

Method: Two cadaveric femora from the same donor were sized, reamed and implanted with identical Stanmore Hips. One was prepared using UK rasps, over-reaming by 2mm, the other using US rasps, over-reaming by 5mm. Serial CT-scans were used to create three-dimensional geometric models of the implanted femora. Two finite element meshes were hand-built in MSC.Marc finite element software, incorporating cortical and cancellous bone, bone cement and prosthesis, with a bonded stem-cement interface. Loading conditions were chosen to represent the heel-strike phase of gait. In order to assess the impact of variability in patient bone density, cancellous bone modulus was varied between 0.06 and 2.90 GPa.

Results: Equivalent stress was examined on the external surface of the cortex and the internal surface of the cement mantle. The lowest cortical bone stresses were proximal and the highest cement stresses around the distal tip of the prosthesis. In the proximal cortex, higher equivalent stresses were observed medially and laterally with a thick cement mantle. Distally, lower cement stresses were observed in the thick cement mantle. With the highest cancellous modulus, there was little difference between the two models. As this modulus was reduced, stress differences between the models became more apparent.

Discussion: Proximal stress shielding was greatest in the calcar, in agreement with clinical findings. The thicker cement mantle led to less stress shielding in this region. Cement stresses, highest around the distal tip of the prosthesis, were larger in the thin cement mantle. This suggests a higher rate of both cracking and bone resorption with thin cement mantles, particularly in patients with low bone density.

Background: Autologous chondrocyte implantation (ACI) was introduced over 15 years ago as a treatment for full-thickness chondral defects in the knee. Current understanding of ACI graft morphology and maturation in humans is limited. The aims of this study were determine the incidence of hyaline-like repair following ACI, and to clarify the relationship between repair morphology and clinical outcome.

Methods: A retrospective review of 194 ACI graft biopsies from 180 patients, and their clinical outcome was conducted. 154 Biopsies were performed 1 year after implantation and 40 biopsies were performed at 2 years. Three techniques of ACI implantation were used; Collagen covered ACI (ACI-C), periosteum covered ACI (ACI-P) and Matrix-Induced ACI (MACI).

Results: At 1 year, hyaline repair tissue was found in 48 (53%) ACI-C grafts, 7 (44%) ACI-P grafts, and 12 (36%) MACI grafts. The frequency of hyaline tissue found in biopsies performed at 2 years (84%) was significantly higher than those performed at 1 year (48.6%), p=0.0001, suggesting that grafts continue to remodel after the first year post implantation.

Clinical outcomes during the first two postoperative years did not vary according to repair morphology type, though hyaline repair was associated with better clinical outcomes beyond 2 years; At 1 year, good to excellent clinical scores were observed in 29 (78.4%) patients with hyaline-like repair, 23 (76.7%) patients with fibrohyaline repair, and 54 (74.0%) patients with fibrocartilage repair. By years 3 and 4 post-implantation, clinical scores further improved in patients with hyaline-like repair yet declined in those with fibrocartilage and fibrohyaline. The difference was significant at 3 years though not at 4 due to the small number of cases.

Conclusions: Achieving hyaline-like repair is critical to the longevity of cartilage repair. The finding of hyaline-like cartilage or fibrohyaline cartilage in 31 of 37 biopsies (84%) performed after 2 years is therefore encouraging and supports further use of the ACI technique.

Aim: This prospective study analyses the histological results of autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint.

Methods: This is a prospective, single centre, single surgeon study. Consecutive patients undergoing autologous chondrocyte transplantation were studied. Chondrocytes from a non-weight bearing area of the knee were harvested and then cultured in vitro. Re-implantation involved injection of the chondrocytes into the defect, which was then sealed with a collagen membrane. One year post-op, patients were evaluated by clinical, arthroscopic and histological assessment. A biopsy of the transplanted region was examined by staining with Erlich’s H& E and Safranin O, polarised light microscopy and by analysis with S100 and immunohistochemistry. Hyaline cartilage content was further assessed by examination of Type IIa & IIb collagen mRNA expression using in-situ hybridisation.

Results: The median age was 31 years. 63 knees were treated. Solitary lesions were treated in 61 knees with two defects being treated in three knees (66 defects in total). The defects were located on the medial femoral condyle in 39 cases, lateral femoral condyle in 14, trochlea in 2 and patella in 11. The defect size ranged from 1–7 cm2 (mean area 3cm2). 40 patients had at least two-year follow-up. Using the Brittberg Rating, 11 had excellent results, with 15 good, 10 fair and 4 poor. The mean Lysholm and Gillquist scores improved from 44 pre-op to 77 two-years post-op. Biopsy at one year confirmed the presence of hyaline cartilage in 22 out of 32 cases (69%). In-situ hybridisation confirmed the presence of Collagen type II in the deep zones of the biopsy with a fibrocartilaginous appearance superficially.

Conclusion This technique can provide an effective treatment for cartilage defects. The histological results are encouraging. Chondrocyte transplantation appears to regenerate tissue with the features of normal hyaline cartilage.

The purpose of this study is to demonstrate that definitive surgery (extraperiosteal excision) is required in patients with osteofibrous dysplasia (OFD) due to the risk of recurrence and co-existent adamantinoma

OFD is an unusual childhood condition, which almost exclusively affects the tibia. It is thought to follow a slowly progressive course and to stabilise after skeletal maturity. The possible link with adamantinoma is controversial with some authors believing that they are part of one histological process. This therefore provides difficulty in recommending treatment options

A retrospective review of OFD was conducted. Using the Stanmore Bone Tumour Unit database 22 cases were identified who were initially diagnosed with OFD or were diagnosed on final histology. All cases were tibial except one lesion in the ulna and one in the fibula

Management was diverse depending on the severity of symptoms and the extent of the lesions encountered. Definitive (extraperiosteal) surgery in the majority of our patients was localized excision for small lesions (less than 50% of the bony circumference) and segmental excision followed by reconstructive surgery for more extensive ones. Seven patients had a sharkbite excision and a further seven were treated with fibula autografting. Of the latter group, one required further excision and bone transport due to recurrence of OFD. An additional five underwent bone transport & distraction osteogenesis using the Ilizarov technique and one had a proximal tibial replacement. Nine initially underwent curettage, but eight recurred (recurrence rate 88.9%). No recurrences occurred following localized extraperiosteal excisions and bone transport. There were three confirmed cases of adamantinoma.

In view of the risk of association of OFD with adamantinoma, and to some extent the continuous morbidity of OFD if left untreated, we believe that radical extraperiosteal excision is indicated in most if not all cases of OFD

Introduction Tissue engineering aims to produce a cellular structure in an extracellular matrix, which when implanted heals tissue defects.

To tissue-engineer bone suitable cells need to be grown on a scaffold. In this study we grew human marrow cells as they can differentiate into osteoblasts, on porous hydroxyapatite (HA) scaffolds, as this is osteoconductive, allows cell penetration and in growth of capillaries after implantation.

Increased extravascular perfusion through bone increases new bone formation. So we reproduced these physiological conditions in our novel bioreactor by perfusing scaffolds at 6ml/hr.

Hypotheses 1. Culture in our bioreactor improved cell penetration through HA scaffolds compared to static conditions. 2. Human mesenchymal stem cells (MSCs) cultured in our bioreactor differentiated into osteo-blasts and produced bone extracellular matrix.

Method MSCs were isolated from 8 human bone marrow aspirates taken from patients following informed consent. For each experiment 16 scaffolds were seeded with MSCs and comparisons were made between the two conditions. After 7 days culture the scaffolds were sectioned longitudinally and the number of cells at increasing depths were counted. The scaffolds were observed under SEM & TEM. Osteoblastic markers ALP and type I pro-collagen (PICP) were measured.

Results Penetration of cells through the scaffolds was significantly greater when cultured in the bioreactor.

After 14 days in bioreactor culture the HA was covered with cuboidal cells, consistent with osteoblasts, however in static culture cells remained fibroblastic. TEM results showed that MSCs in the bioreactor produced organised collagen matrix after 21 days and osteoid by 28 days, but no collagen matrix was observed following static culture.

ALP and PICP were significantly greater over 15 days culture when in our bioreactor.

Conclusions These results show that when MSCs were cultured in our bioreactor they attached and penetrated through porous HA scaffolds, whereas in static conditions few cells penetrated below 2mm. Our bioreactor significantly improved 3-dimensional growth, resembling tissue.

Moreover, MSCs grown on HA in the bioreactor produced significantly more ALP and PICP indicating osteoblastic differentiation. Furthermore, bone osteoid was produced.

Therefore this culture method could be use to convert autologous MSCs from human marrow into tissue-engineered bone which could be used to heal defects after tumor excision.

We prospectively randomised 104 consecutive patients undergoing primary cemented total knee arthroplasty to receive either a standard suction drain© (Redivac) or autologous transfusion drain® (Bellovac). There were fifty two patients in each group. Randomisation was performed using a software program (Minim) which set to stratify patients based on their age, sex and body mass index (BMI). All procedures were performed under pneumatic tourniquet.

Drains were released in recovery room 20 minutes after surgery and were removed 24 hours following surgery. Blood collected in the standard suction drain was discarded but blood collected in the autologous transfusion drains was transfused unwashed to the patient within six hours of collection.

13 patients (25%) in the study group had two or more units of homologous blood transfused in addition to the blood collected postoperatively and re-transfused (Average= 438mls). 12 patients (23%) in the control group had two or more units of homologous blood transfused. No sepsis, transfusion reactions, or coagulopathies were associated with the autologous blood re-transfused in the study group.

The use of autologous transfusion system (Bellovac) proved to be safe but failed to reduce the need for postoperative homologous blood transfusion following uncomplicated total knee arthroplasty.