Objectives:

To determine the diagnostic performance of image-guided percutaneous core needle biopsy (CNB) in patients presenting with pathologic fractures of the appendicular skeleton.

A retrospective audit identified 129 consecutive patients presenting with pathological fractures to a specialist orthopaedic oncology unit over a 9 year period. All patients underwent percutaneous CNB using CT (n=98), fluoroscopy (n=15) or US (n=16) guidance. In all cases MRI or CT was available prior to biopsy to assess the presence and degree of extra-osseous tumour mass. The resulting sample was classified as diagnostic (Group 1) or non-diagnostic (Group 2) on histopathological study. Diagnostic performance was evaluated on the basis of the diagnostic yield and accuracy; these were related to the site of the lesion and presence/absence of extra-osseous mass.

Of 129 biopsies, 99 (77%) were classified as Group 1 and 30 (23%) as Group 2. The commonest sites of pathological fracture without associated soft tissue component and resulting in a non-diagnostic biopsy were the proximal femur and proximal humerus. The average cross-sectional diameter of lesions in Group 1 was 5.7 x 5.9cm. Of the 30 lesions comprising Group 2, no soft tissue component was identified on pre-biopsy cross-sectional imaging in 27 lesions (90%) whereas the remaining 3 (10%) showed a smaller extra-osseous soft tissue component compared to the lesions in Group 1.

Image-guided percutaneous CNB is a reliable method for obtaining a tissue diagnosis in patients presenting with a pathologic fracture of the appendicular skeleton with high accuracy rate. However, those lesions which are purely intra-osseous or have only very small extra-osseous components are likely to be associated with a non-diagnostic biopsy, and should be considered for a primary open procedure.

Introduction: Primary or secondary bone tumours of the distal tibia are uncommon. Before the development of endoprostheses in the 1970’s, the primary treatment for these was below knee amputation. Limb salvage is now possible without adversely affecting survival largely due to improvements in chemotherapy. We report the clinical and functional outcome of six patients who underwent limb salvage with endoprosthetic reconstruction of the distal tibia and ankle joint for malignancy.

Methods: Retrospective review of all patients who underwent limb salvage with endoprosthetic reconstruction of the distal tibia and ankle joint at our institution. Data was collected from the bone tumour database, medical records, imaging studies, clinic reviews and individual structured patient questionnaires. MSTS and TESS scores were used to assess functional outcome.

Results: Six patients underwent distal tibial replacement for malignant bone tumours of the distal tibia. There were 4 males and 2 females with a mean age of 31.2 years (range 13 to 68) and mean follow-up of 35 months (range 13 to 76). One patient died of non-neoplastic disease at 76 months. Two patients had Ewings sarcoma, two had osteosarcoma, one had malignant fibrous histiocytoma and one had adamantinoma.

No patient had metastases at presentation and no patient developed local recurrence or distant metastases post-operatively. Four patients developed infection, for which two required below knee amputation and two suppressive antibiotics. Hardware failure was seen in one patient with infection which was managed by below knee amputation. One patient required sub-talar fusion and calcaneal osteotomy for persistent ankle pain.

A child who underwent the procedure age 13 developed a 5 cm leg-length discrepancy once skeletally-mature. Mean MSTS and TESS scores for the three patients who still had a functioning endoprosthesis were 77% and 79% respectively.

Conclusion: Limb salvage with distal tibial combined with ankle joint replacement can be used as an alternative to below knee amputation in patients with bone tumours of the distal tibia. Due to the difficulties in achieving adequate soft tissue cover, patients should be counselled regarding the high potential complication rate which can lead to significant morbidity, functional deficit and further surgical intervention.

Introduction: Initial results for the management of osteochondral defects with both ACI-C and MACI have been encouraging, showing significant clinical improvements. This study set out to report the functional, clinical and histological outcomes in our institution following nine years experience of cartilage-cell transplants.

Aim: Reporting results of nine-year experience of clinical and arthroscopic assessment in the use of ACI and five year experience of MACI in the management of symptomatic, full-thickness chondral and osteochondral defects in the knee.

Method: Following preoperative functional assessments, arthroscopic harvesting of chondrocytes for culture was performed and patients underwent ACI-C or MACI. In ACI-C a covered technique is employed using a porcine-derived type I/III collagen membrane sutured in place; MACI requires cultured autologous chondrocytes to be seeded in a bi-layered type I/III collagen membrane which is glued into position. An arthroscopy was performed between 12 and 24 months post-procedure to assess graft coverage and biopsies taken to determine extent of hyaline, mixed and fibro-cartilage proliferation.

Results: 354 patients underwent either ACI-C (103) or MACI (251) with an average age of 31.3 (15–54). Cincinnati knee rating scores recorded prior to assessment arthroscopy for ACI-C: 58.6 (12 – 92) and MACI: 48.4 (11 – 90) showed improvement at follow up with means of 84.0 for ACI-C, with 78% of patients scoring good or excellent at nine years, and a mean of 82.3% in the MACI group at five years, with 87% of patients recording good or excellent scores; statistically significant improvement was also noted in Bentley Functional score. Biopsies of the transplants taken between 12 and 24 months revealed proliferation of hyaline and mixed cartilage (hyaline and fibro-cartilage) in 47% patients; the later the biopsy was taken post-implantation, it was more likely to reveal hyaline tissue.

Conclusion: Results to date suggest significant clinical and arthroscopic improvement following ACI-C and MACI, with evidence of proliferation of hyaline cartilage at the transplant site and evidence to suggest dynamic improvement in hyaline-nature of cartilage. Limited differences are noted between the outcomes of the two techniques.

The use of massive endoprostheses following bone tumour resection is well recognised. Where possible, joint salvage rather than joint replacement is usually attempted. However cases arise where there is insufficient bone following tumour resection to allow adequate fixation of a joint sparing prosthesis. We reporta series of 4 patients (aged 4–12), treated between 1994 and 2008, in which irradiated autologous bone has been combined with a diaphyseal or distal femoral replacement in order to preserve the native hip joint.

There were 3 cases of osteosarcoma and 1 case of Ewing‘s sarcoma. After a mean follow-up of 53.5 months (range 9–168), all four patients are alive without evidence of local recurrence or metastases. One implant was revised after 14 years following fracture of the extending component of the growing endoprosthesis. There have been no cases of loosening or periprosthetic fracture.

This is the first report of irradiated autologous bone with joint sparing endoprostheses in skeletally immature patients.

This case highlights the close association between osteo-fibrous dysplasia (OFD) and adamantinoma, drawing attention to the role for more radical treatment options when treating OFD. We discuss the advancements in joint-sparing endoprostheses using bicortical fixation. Finally we describe a unique biomedical design allowing for manufacture of an end cap to allow amputation through a custom made joint-sparing proximal tibial replacement as opposed to an above knee amputation.

A 37 year old presented 7 years ago having sustained a pathological fracture of her tibia. Subsequent biopsy revealed OFD, curettage with bone graft was performed. She later developed recurrence, two percutaneous biopsies confirmed OFD. 6 years following her initial diagnosis she was referred to RNOH with further recurrence, a biopsy at this stage revealed a de-differentiated adamantinoma. A joint-sparing proximal tibial replacement was performed and adjuvant chemotherapy administered, she remained well for one year. Recurrence was noted at the distal bone-prosthesis interface, histology revealed a high grade dedifferentiated osteosarcoma, limb preservation was not deemed possible and an amputation was performed through the prosthesis. The proximal tibial device was uncoupled leaving a residual 7 cms insitu, a small custom made end cap was attached to the remaining prosthesis and a myocutaneous flap fashioned over it, this ultimately enabled the patient to mobilise well with a below–knee orthotic device.

This case highlights the need for more radical surgery when treating cases of OFD and the relationship between OFD and adamantinoma. It also introduces a joint-sparing proximal tibial device for use in proximal tibial tumours that do not invade the proximal tibial metaphysis. The biomechanical design solution has given us the unique option of preserving the knee joint allowing the patient a below knee amputation whereas previously an above knee amputation would have been performed thereby significantly reducing her functional outcome.

Elastofibroma dorsi is a rare, benign, slow-growing ‘pseudotumour’ classically presenting as an ill defined mass at the inferior pole of the scapula. Typical symptoms include mass, pain, scapular snapping and impingement like features. There is a predilection for females after the fifth decade of life. The aetiology is unclear.

We identified 15 patients (21 tumours) with a diagnosis of elastofibroma. Seven lesions were found on the left side and fourteen on the right; bilateral lesions were found in six patients. The male:female ratio was eight:seven and mean age at presentation was 60.9 years (range 40 – 71). The mean duration of symptoms (most commonly pain, mass and scapular snapping) prior to presentation was 25.8 months. Eighteen tumours were excised with a mean follow-up of 4.2 years (0.25–16). Four lesions were diagnosed by combined MRI and CT guided biopsy, the remainder identified using MRI alone. All patients were asked specifically about symptoms, occupation, family history and employment history (including hobbies). Pain was assessed using the Visual Analogue Score (VAS) and functional outcome using the Stanmore Percentage of Normal Shoulder Assessment (SPONSA) Score. Range of forward flexion of the shoulder joint was also assessed.

In the operative group, the mean VAS score improved from 4.6 (0–10) pre-operatively to 2.5 (0–8) post-operatively. Mean SPONSA scores improved from 61.5% (20 – 100) to 81.8% (30 – 100). Mean pre-operative forward flexion was 135 degrees (70 – 180), this improved to 166 degrees (100 – 180) post-operatively. A high number of patients had been involved in occupations involving heavy lifting. MRI had a 100% sensitivity in identifying elastofibroma when correlated with histopathological evaluation.

This series demonstrates that elastofibroma may be reliably diagnosed using MRI alone and, in the symptomatic patient, pain and function may be improved through operative excision.

Primary solitary fibrous tumour (SFT) of bone is extremely rare with few cases reported in the literature. The incidence of the lesion is 0.08% of all primary bone tumours (0.1% of primary malignant bone neoplasms). Previously, such lesions may have been reported as haemangiopericytoma (HP).

Despite being previously considered as separate entities, the two types of tumour (SFT and HP) are now generally accepted as related, sharing similar morphological and immunohistochemical features. Cytogenetic and molecular analysis has, so far, been unable to unite or divide the two. Although frequently having a histologically benign appearance or being labelled as intermediate grade, these tumours may exhibit an unpredictable clinical course and behave in an aggressive manner. We present two cases of osseous solitary fibrous tumour (cellular haemangiopericytoma).

Using the histopathology and bone tumour databases at our institution, we identified two patients (one female aged 21 and one male aged 40) with a histopathological diagnosis of osseous SFT. The site of primary tumour in both patients was the sacrum. In the female patient, the lesion was confined to the sacrum and she underwent curettage. In the male patient, the tumour extended beyond the sacrum to the sacro-iliac joint, ilium and gluteal mass, therefore, total sacrectomy was performed. At presentation neither patient had evidence of metastatic spread.

The female patient was disease free at four years with no evidence of recurrence of metastases. The male patient developed metastases in both lung fields and bone (ribs, vertebrae) three years post-operatively and died four years post-operatively.

Orthopaedic surgeons and histopathologists should remain aware of SFT due to its erratic behaviour and the recent move towards unifying it with HP in a continuous spectrum. We recommend early staging and treatment of these tumours, even for histologically benign/low grade lesions, due to their potentially aggressive behaviour.

Within a study group of 102 consecutive patients diagnosed at a supra-regional bone tumour unit with chondrosarcoma of the femur, tibia or humerus, an association with previously treated breast cancer was noted.

There were 58 female patients and 44 male patients. The study group contained six females (10%, mean age 53 years) who had previously been treated for breast cancer, a higher proportion than would be expected. They were referred following identification of a solitary area of increased activity on routine screening with isotope bone scan, presumed to be a solitary bony metastasis.

Most (86%) of this breast carcinoma sub-group had developed low-grade bone chondrosarcoma (Trojani grade 0.5-I) and only one case (14%) had developed high-grade chondrosarcoma (Trojani grade II-III).

A suspicious long bone lesion on bone scan in a patient with a past medical history of breast cancer must, therefore, not be assumed to be a metastasis without further investigation; the possibility of a chondral lesion should be considered. It is important that patients receive a full multidisciplinary team investigation prior to treatment in order to obtain the correct tissue diagnosis, as the management of these conditions is often different.

Our study suggests there may be a relationshipbetween patients previously treated for breast cancer and the development of subsequent chondrosarcoma.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft tissue neoplasm most commonly presenting in young to middle-aged adults. LGFMS is an indolent tumour with a deceptively benign histological appearance. Local recurrences are not uncommon and the tumours can metastasise. A particular gene translocation, FUS-CREB3L2, has been shown to occur commonly in cases of LGFMS. The literature suggests that the FUS-CREB3L2 fusion-gene is a specific marker for LGFMS.

We report the cytogenetic analysis of 29 cases of LGFMS, and clinical outcomes of 21 patients treated surgically between 1998 and 2008 at our regional bone and soft-tissue tumour centre. The mean age was 45.4 years. The most common location of tumours in our series was the lower limb. The mean follow-up was 30.1 months (range 0 to 125 months). To date, there have been no cases of local recurrence or metastasis.

Fifteen of our patients (52.2%) were FUS-CREB3L2 translocation-positive. This suggests either that the translocation incidence in our LGFMS series is lower than other studies, or that reverse-transcriptase polymerase chain reaction (PCR) is substantially less sensitive than the literature suggests. The patients in this series testing positive presented at a younger age (38.2 years, compared to 45.6 years), and had larger tumours than their negative counterparts (mean diameter 97.6mm, compared to 65.2mm), although there was no difference in clinical outcome.

We conclude that PCR testing for the FUS-CREB3L2 translocation is a useful tool for confirming the diagnosis of LGFMS, but has no role in predicting short-term clinical outcome. In our experience it is not necessary to perform wide excision, and marginal margins are adequate. Longer-term follow-up is required to elucidate whether the previously reported recurrence and metastasis rates are a true reflection of the nature of this tumour, and may identify differences in the long-term clinical outcome between translocation-positive and negative patients.

Chondrosarcoma is the second most common primary malignant bone tumour. Distinguishing between grades is not necessarily straightforward and may alter the management of the disease. We evaluated the correlation between the pre-operative needle biopsy and excision biopsy histological grading of chondrosarcoma of the femur, tibia and humerus.

A consecutive retrospective series of 100 patients with a histological diagnosis of chondrosarcoma was reviewed. Twenty-one patients were excluded because 20 had only excision biopsy and one had only the pre-operative biopsy on record, thus this series included 79 available cases. In 11 instances, there was a discrepancy in histological grade.

Therefore, there was an 86% (68 out of 79) accuracy rate for pre-operative histological grading of chondrosarcoma, based on needle biopsy. However, the accuracy of the diagnostic biopsy to distinguish low-grade from high-grade was 90% (71 out of 79).

Following resection of tumours in the distal femur, reconstruction with joint-sparing prostheses have shown good short-term functional outcomes. There is however limited literature on the affect of knee-sparing prostheses on function of the distal femoral physis in children of bone growing age.

We discuss two patients, a male (11yrs) and female (10yrs) who had joint-sparing distal femoral prostheses inserted for treatment of Ewing’s sarcoma. The knee joint, along with the distal growth plate, was preserved and fixed to the distal end of the prosthesis using uni-cortical screws positioned distal to the physis. In the female, these screws were removed 6 months postop due to prominence of the screws under the skin. In both patients, we assessed radiographs from immediately post[surgery and the most recent follow-up (20 and 28 months respectively). In each set, for the operated limb, we measured the height and width of the distal femoral epiphysis, the total length of the femur and the length of the proximal femoral bone segment from the femoral head to the proximal bone-prosthesis interface. In addition, postoperative assessments of leg lengths, bilaterally, were documented.

In both patients, distal femoral epiphyseal height and width in the operated leg showed no significant change following endoprosthetic replacement. In the female, growth did not resume even after removal of the epiphyseal screws. In both patients, lengths of the femur and the proximal bone segment increased significantly following surgery. The patients demonstrated no clinical leg length discrepancy at the most recent follow-up.

This study suggests that the function of the distal femoral growth plate ceases following insertion of joint-sparing distal femoral endoprostheses, probably due to trans-physeal fixation. This does not appear to resume following early removal of distal screws. The proximal growth plate, however, continues to function adequately enough to maintain symmetry in overall leg length.

Granular Cell Tumours are rare mesenchymal soft tissue tumours that arise throughout the body and are believed to be of neural origin. They often present as an asymptomatic slow-growing benign solitary lesion but may be multifocal. One to two percent of cases are malignant and can metastasise.

Described series in the literature are sparse. We examined our database and identified eleven cases in ten patients treated surgically and followed-up for a period of over six years (May 2002 to January 2009) in our regional bone and soft tissue tumour centre.

Five tumours were located in the lower limb, four in the upper limb and two in the axial skeleton. Mean patient age was 31.2 years (range 8 to 55 years). Excision was complete in one case, marginal in five cases and intra-lesional in five cases. No specimens showed evidence of malignancy. No patients required postoperative adjuvant treatment. Mean follow-up was 19.3 months (range 1 to 37 months), with no cases of local recurrence. One case was multi-focal.

Histopathological examination revealed the classical features of granular cell tumour in all cases. Typically, tumour cells were diffusely and strongly positive for S100 protein by immunohistochemistry, whereas the other markers tested were negative.

We believe this case series to be the largest of its type in patients presenting to an orthopaedic soft tissue tumour unit. We present our findings and correlate it with findings of other series in the literature.

Purpose: To determine if Cobalt-Chrome (CoCr) femoral components of knee replacement components roughen significantly, and when significant roughening may start.

Methods:

Retrieval study:

14 knee replacement components were retrieved after revision procedures. The average surface roughness (Ra) of the articulating regions of each condyle was measured by surface profilometry and compared to Ra of non-articulating regions, which acted as controls on each implant.

In vitro testing:

Pin-on-plate testing of 6 paired CoCr pins and vacuum γ-irradiated UHMWPE discs was carried out under a force of 2.3kN at 1Hz to investigate how the articular Ra of CoCr pins varied with increasing number of cycles. Ra was measured at 0, 10, 100 and 1000 cycles using surface profilometry.

Results:

Retrieval analysis:

Average medial femoral condyle Ra was significantly greater than control Ra (p=0.040). Average lateral femoral condyle Ra was not significantly greater than control Ra (p=0.158). Significantly higher average Ra was seen on the medial condyles when compared with the lateral condyles (p < 0.05). 8/14 retrieved femoral components had ≥1 significantly roughened condyle (p< 0.05).

In vitro testing:

At 100 and 1000 cycles the Ra of the CoCr pins was significantly greater than Ra at 0 cycles (p< 0.05).

Conclusion: A large proportion of femoral components of knee replacement implants roughen significantly in vivo, a finding supported by our in vitro testing which indicates that roughening may begin very early on. This may have important implications for aseptic loosening of knee replacement components. However, the average Ra of those CoCr surfaces significantly (p< 0.05) roughened was within acceptable limits for orthopaedic implants (0.050μm).

The proximal tibia is the second most common site for primary bone tumours. As a result of simultaneous advances in chemotherapy, surgical and biomechanical techniques limb salvage is now a practical option. We report the clinical and functional outcomes of eight patients who underwent limb salvage with a new form of endoprosthetic proximal tibial replacement that allows preservation of the knee joint.

A retrospective, case series of 8 patients who underwent joint sparing proximal tibial replacement between 2004 and 2008. There were 2 males and 6 females with a mean age of 28.9 years (8–43) with overall mean follow up of 35 months (4–48). Functional outcomes were assessed using the Musculoskeletal Tumour Society (MSTS) rating score and revised Oxford Knee Score (OKS)

Five patients had osteosarcoma, one patient had malignant fibrous histiocytoma, another adamantinoma and the final patient had Ewing’s sarcoma. All patients had complete tumour excision, neoadjuvant chemotherapy and to date there have been no distant metastasis. One patient however required a below knee amputation through the prosthesis due to local recurrence at the distal bone/prosthesis interface. Another patient fell at postop day 8 and fractured through the tibial metaphyseal bone requiring ORIF; this healed in extension and ultimately required revision to a proximal tibial replacement 20 months later. Mean MSTS and OKS for the remaining 6 patients were 77% (57–90) and 40 (36–46) respectively.

Limb salvage preserving the knee joint is an effective alternative to a proximal tibial replacement when the metaphyseal bone is tumour free. The joint sparing prosthesis has a favourable functional result when compared to the joint sacrificing prostheses. Retaining the native joint improves functional outcomes and reduces the peak loads through the prosthesis. There was no short-term evidence of loosening. Further follow up is required to ascertain the long-term outcomes of this new prosthesis.

Introduction: Metal-on-metal arthroplasties are being used for their increased durability and reduced requirement for revision. Previous data reports that metal-on-metal bearing surfaces release three times more cobolt and chromium ions than metal-on-polyethelene hip replacements. Data also suggests that these metal ions can cause DNA damage.

Method: A prospective study of patients (aged 60–80), meeting exclusion criteria were selected and randomised to metal-on-metal or metal-on-polyethylene articulation. Patients were reviewed preoperatively (control model) and at 3 months, 6 months and one year postoperatively. On each occasion blood tests were taken to quantify metal ion levels (chromium, cobalt, nickel, vanadium and titanium) and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hybridization (FISH).

Results: The number of chromosome aberrations increased with time; in particular there was a statistically significant increase in aneuploidy after one year, there was also an increase in chromosome translocations. There was a similar increase in blood concentration of metal ions over this same time period which proved significant. Higher levels of metal ions were seen in the metal-on-metal group when compared with the metal-on-polyethylene.

Conclusion: This study has highlighted the effects of metal ions on chromosome replication in particular causing aneuploidy aberrations. This provides evidence of the short-term effects of metal-on-metal arthroplasty but further research needs to be undertaken to assess long-term risk and also the risk associated to other cell lines.

Medical records of children < /=5 years, treated by the London sarcoma service for malignant primary bone tumours (average new cases osteosarcoma (OS)/Ewings sarcoma (ES), all ages: 125/year) between 1999 and 2009, were reviewed.

Results: 5 OS and 6 ES. Mean age – 4.2 years (range 2.1–5.8), 8/11 males. OS primary sites: distal femur (2), proximal femur (1) and proximal humerus (2); localised tumours only. Primary sites in the ES cohort included 1 distal femur, 2 chest wall (1 – spinal extension), 1 buttock (spinal extension), 1 temporal bone and 1 ulna; 1 had bone/bone marrow involvement, 1 had chest metastases. 4/5 OS (Euramos, MRC B007) and 5/6 ES (Euro-Ewings 99) were entered into phase III clinical trials. Delayed surgery for OS occurred at mean 12.1 weeks (range 11–13) – 4 limb salvage prostheses with 2/4 non-invasive growers, 1 forequarter amputation. All had a good (> 90% necrosis) histologic response to neoadjuvant therapy. Delayed surgery for ES occurred at mean 21.7 weeks (range 12.8 – 35), 1 limb salvage with prosthesis (non-invasive grower), 1 biological reconstruction; remainder had tumour resections. Histologic response: 50% good. In the OS cohort, 1 child died a toxic death; 1 developed pulmonary metastases and died 2 years from diagnosis; 1 has a metastatic recurrence in the opposite humerus 2 years from diagnosis and starts 2nd line therapy; 1 had local recurrence 1 year from diagnosis but alive at 7.4 years;1 alive/disease free at 2.5 years. In the ES cohort 5/6 are alive disease free -1, 4.1, 5.2, 6.9 and 7 years from diagnosis; 2 needed 2nd line therapy for recurrent distant disease 4.5 and 5.8 years off therapy, 1 of whom has just recurred again (6.1 years from diagnosis).

Conclusion- improving early survival rates in the very young with OS remains a significant challenge. Quality of survival requires further age-appropriate study.

Introduction: Autologous Chondrocyte Implantation (ACI) is a treatment option for full-thickness chondral, or osteochondral injuries that are painful and debilitating. Goals of surgery and rehabilitation include replacement of damaged cartilage with hyaline or hyaline-like cartilage, leading eventually to improved level of function. Intermediate and long-term results are promising in terms of functional and clinical improvement.

Purpose: To explore the hypothesis that the quality of the repair tissue, formed following Autologous Chondrocyte Implantation (ACI), improves with time post-surgery.

Methods and Results: Two hundred and forty eight patients who underwent autologous chondrocyte implantation in our institution were studied after having had post implantation biopsies of the repair tissue. Mean timing of biopsy was 14.8 months (range 3–55). 59 biopsies gave hyaline tissue (24%), 67 mixed hyaline and fibrocartilage (27%), 113 biopsies were fibrocartilage only (46%) and 9 patients had a fibrous tissue biopsy result (9%). Due to NHS restraints and waiting list targets biopsies were actually performed at various time points post implantation allowing us to statistically correlate histological findings with the maturity of the repair tissue.

Our statistical analysis suggests that if time post implantation doubles then the likelihood of a favourable histological outcome increases significantly.

Conclusion: Autologous chondrocyte implantation forms a durable repair tissue that remodels and continues to improve in quality with time. It is recommended that for future research/study purposes 24 months is used as an optimal time to look at histology, since our data show that outcome is still improving until this point.

Introduction: Initial results for the management of osteochondral defects with both ACI-C and MACI have been encouraging, showing significant clinical improvement. This single-centre study set out to determine any significant difference in outcomes between ACI-C and MACI.

Aim: Reporting three year follow up of clinical and arthroscopic assessment of prospective analysis of ACI-C and MACI used in the management of symptomatic, full-thickness chondral and osteochondral defects in the knee.

Method: Following assessment arthroscopy and harvesting of chondrocytes for culture, patients were randomised into the ACI-C or MACI arm and underwent their respective procedures one month later. In ACI-C a covered technique is employed using a porcine-derived type I/III collagen membrane sutured in place; MACI requires cultured autologous chondrocytes to be seeded in a bi-layered type I/III collagen membrane which is glued into position. An arthroscopy was performed at 12 and 24 months postprocedure to assess graft coverage and biopsies taken to determine extent of hyaline, mixed and fibro-cartilage proliferation.

Results: 102 patients underwent either ACI-C (44) or MACI (58) with an average age of 33.6 (14–52). Mean Cincinnati knee rating scores recorded prior to assessment arthroscopy for ACI-C: 45.2 (10 – 94) and MACI: 45.5 (10 – 90) showed improvement at follow up with 63% of patients in the ACI-C group scoring good or excellent at three years, and 60% in the MACI group. ICRS arthroscopy scores were good or excellent in 91.4% of ACI-C and 76.1% of MACI patients at 24 months. Biopsies of the transplants at 24 months revealed proliferation of hyaline and mixed cartilage (hyaline and fibro-cartilage) in 48.6% of the ACI-C and 30.5% of the MACI patients.

Conclusion: Results to date suggest significant clinical and arthroscopic improvement following ACI-C and MACI, with evidence of proliferation of hyaline cartilage at the transplant site. Limited differences are noted between the outcomes of the two techniques.

Purpose: We attempted to identify whether patients with early evidence of osteoarthritis (OA) on their pre-operative radiographs were associated with poorer outcomes after Autologous Chondrocyte Implantation (ACI).

Methods: We retrospectively reviewed radiographs of 94 consecutive patients who underwent ACI and had already had their knee function assessed according to the Modified Cincinatti Score 2 years following surgery. Changes were graded according to The Kellgren and Lawrence (K& L) and the Stanmore grading system. Two independent observers analysed the films to assess the reproducibility and accuracy of these grading systems for assessment of OA in the knee.

Results: Patients were divided into 2 groups; Group A were patients with excellent/good outcome (52 patients), those with fair/poor outcome were Group B (42 patients).13 patients in Group A and 21 patients in Group B had radiographic evidence of OA (p< 0.025). In 34 patients who had OA (mean age 33.6) the increase in Cincinatti score following surgery was minimal (33.5 to 37.5). In 60 patients where there was no evidence of OA (mean age 33.7) the score increased from 40 to 53.4. The inter-observer variation was greater using K& L (Kappa=0.31) compared with the Stanmore grading systems (Kappa=0.72).

Conclusions: Patients with early radiographic evidence of OA are unlikely to gain maximum benefit from ACI. Furthermore, we recommend the use of Stanmore grading system for the assessment of OA as it is more reproducible than the K& L grading system.

Introduction: The use of custom made CAD-CAM femoral stems in primary Total Hip Replacement allows preservation of valuable bone stock in anatomically challenging femora whilst optimising biomechanics and improving function. The custom prosthesis design and manufacturing process is carried out with the aid of computed tomography (CT), a system of tomographic image processing, a Computer–Aided Design (CAD) system and a Computer–Aided Manufacturing (CAM) system.

Aim: To report seven year minimum follow up of a custom made and designed femoral component used in total hip replacement, focusing on clinical and radiographic evidence of failure.

Methods: Patients who had an uncemented total hip arthroplasty, by one of the two senior authors, with a CAD-CAM hip between February 1993 and February 2000 were retrospectively studied. An independent observer evaluated all patients radiologically using Engh’s criteria of osteointegration and clinically using Harris and Oxford Hip Scores.

Results: 85 patients (47 male, 38 female) (102hips) underwent THA for a variety of reasons between February 1993 and February 2000. Average age was 53.7 (25.4–91.5). Average follow up was 9.3 years (7–15). The aetiologies for THA were: Developmental Dysplasia of Hip (22 hips), Osteoarthritis (25), Slipped Upper Femoral Epiphysis (3), Skeletal Dysplasia (11), Trauma (9), Perthe’s Disease (6), Avascular Necrosis (14), Tumour (4) and other (8). At last follow up 4 hips had been revised: 2 for aseptic loosening, 1 for deep infection and 1 for excessive acetabular cup liner wear. 84 patients were evaluated (one deceased from unrelated causes). Average Harris Hip Score was 81 (range 53–96). Average Oxford Hip Score was 24 (range15–43). A full set of x-rays was available for 73 patients and when evaluated all were radiographically stable. Endosteal bone formation or spots welds were present on all 73 of the x-rays. Radiolucent lines at the bone-implant interface were present on 7/73 x-rays but did not correlate with clinical problems. There was no evidence of bone pedestal formation.

Conclusions: Clinical results are good to excellent with little radiographic evidence of failure. CAD-CAM hips can be safely and reliably used for a variety of aetiologies with predictable result at least up to seven years postoperatively.