Aims

Revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA) are complex procedures with higher rates of re-revision, complications, and mortality compared to primary TKA and THA. We report the effects of the establishment of a revision arthroplasty network (the East Midlands Specialist Orthopaedic Network; EMSON) on outcomes of rTKA and rTHA.

The long term biological effects of wear products following total hip arthroplasty (THA) are unclear. However, the indications for THA are expanding, with increasingly younger patients undergoing the procedure.

This prospective, randomised study compared two groups of patients undergoing THA after being randomised to receive one of two different bearing surfaces: metal-on-polyethylene (MoP) n = 22 and metal-on-metal (MoM) n = 23. We investigated the relationship between three variables: bearing surface (MoP vs MoM), whole blood levels of chromium (Cr) and cobalt (Co) and chromosomal aberrations in peripheral lymphocyte pre-operatively and at one, two and five years post-surgery.

Our results demonstrated significantly higher mean cobalt and chromium (Co and Cr) blood levels in the MoM group at all follow-up points following surgery (p < 0.01), but there were no significant differences in the chromosomal aberration indices between MoM and MoP at two or five years (two years: p = 0.56, p = 0.08, p = 0.91, p = 0.51 and five years: p = 0.086, p = 0.73, p = 0.06, p = 0.34) for translocations, breaks, loss and gain of chromosomes respectively. Regression analysis showed a strong linear relationship between Cr levels and the total chromosomal aberration indices in the MoM group (R² = 0.90016), but this was not as strong for Co (R² = 0.68991). In the MoP group, the analysis revealed a poor relationship between Cr levels and the total chromosomal aberration indices (R² = 0.23908) but a slightly stronger relationship for Co (R² = 0.64292). Across both groups, Spearman’s correlation detected no overall association between Co and Cr levels and each of the studied chromosomal aberrations. There remains no clear indication which THA bearing couple is the most biocompatible, especially in young active patients. While THA continues to be very successful at alleviating pain and restoring function, the long-term biological implications of the procedure still require further scrutiny.

Cite this article: Bone Joint J 2015;97-B:1183–91.

Introduction:

Non-invasive extendible endoprostheses (NIEE) were primarily developed for salvage after musculo-skeletal tumour surgery in the immature skeleton. However, they may also have a unique application to manage complex limb reconstruction in revision surgery to address limb-length inequality in the mature skeleton. The aim of this study is to present the minimum 2 –year results of using non-invasive extendible endoprostheses for complex lower limb reconstruction.

In patients with a tumour affecting the distal ulna it is difficult to preserve the function of the wrist following extensive local resection. We report the outcome of 12 patients (nine female, three male) who underwent excision of the distal ulna without local soft-tissue reconstruction. In six patients, an aggressive benign tumour was present and six had a malignant tumour. At a mean follow-up of 64 months (15 to 132) the mean Musculoskeletal Tumour score was 64% (40% to 93%) and the mean DASH score was 35 (10 to 80). The radiological appearances were satisfactory in most patients. Local recurrence occurred in one patient with benign disease and two with malignant disease. The functional outcome was thus satisfactory at a mean follow-up in excess of five years, with a relatively low rate of complications. The authors conclude that complex reconstructive soft-tissue procedures may not be needed in these patients.

Cite this article: Bone Joint J 2014;96-B:1392–5.

The pre-operative differentiation between enchondroma, low-grade chondrosarcoma and high-grade chondrosarcoma remains a diagnostic challenge. We reviewed the accuracy and safety of the radiological grading of cartilaginous tumours through the assessment of, first, pre-operative radiological and post-operative histological agreement, and second the rate of recurrence in lesions confirmed as high-grade on histology. We performed a retrospective review of major long bone cartilaginous tumours managed by curettage as low grade between 2001 and 2012. A total of 53 patients with a mean age of 47.6 years (8 to 71) were included. There were 23 men and 30 women. The tumours involved the femur (n = 20), humerus (n = 18), tibia (n = 9), fibula (n = 3), radius (n = 2) and ulna (n = 1). Pre-operative diagnoses resulted from multidisciplinary consensus following radiological review alone for 35 tumours, or with the addition of pre-operative image guided needle biopsy for 18. The histologically confirmed diagnosis was enchondroma for two (3.7%), low-grade chondrosarcoma for 49 (92.6%) and high-grade chondrosarcoma for two (3.7%). Three patients with a low-grade tumour developed a local recurrence at a mean of 15 months (12 to 17) post-operatively. A single high-grade recurrence (grade II) was treated with tibial diaphyseal replacement. The overall recurrence rate was 7.5% at a mean follow-up of 4.7 years (1.2 to 12.3). Cartilaginous tumours identified as low-grade on pre-operative imaging with or without additional image-guided needle biopsy can safely be managed as low-grade without pre-operative histological diagnosis. A few tumours may demonstrate high-grade features histologically, but the rates of recurrence are not affected.

Cite this article: Bone Joint J 2014; 96-B:1098–105.

The management of failed autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI) for the treatment of symptomatic osteochondral defects in the knee represents a major challenge. Patients are young, active and usually unsuitable for prosthetic replacement. This study reports the results in patients who underwent revision cartilage transplantation of their original ACI/MACI graft for clinical or graft-related failure. We assessed 22 patients (12 men and 10 women) with a mean age of 37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The mean period between primary and revision grafting was 46.1 months (7 to 89). The mean defect size was 446.6 mm² (150 to 875) and they were located on 11 medial and two lateral femoral condyles, eight patellae and one trochlea.

The mean modified Cincinnati knee score improved from 40.5 (16 to 77) pre-operatively to 64.9 (8 to 94) at their most recent review (p < 0.001). The visual analogue pain score improved from 6.1 (3 to 9) to 4.7 (0 to 10) (p = 0.042). A total of 14 patients (63%) reported an ‘excellent’ (n = 6) or ‘good’ (n = 8) clinical outcome, 5 ‘fair’ and one ‘poor’ outcome. Two patients underwent patellofemoral joint replacement. This study demonstrates that revision cartilage transplantation after primary ACI and MACI can yield acceptable functional results and continue to preserve the joint.

Cite this article: Bone Joint J 2014;96-B:54–8.

We prospectively assessed the efficacy of a ceramic-on-metal (CoM) hip bearing with uncemented acetabular and femoral components in which cobalt­–chrome acetabular liners and alumina ceramic heads were used.

The cohort comprised 94 total hip replacements (THRs) in 83 patients (38 women and 45 men) with a mean age of 58 years (42 to 70). Minimum follow-up was two years. All patients had pre- and post-operative assessment using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Oxford hip score and Short-Form 12 scores. All showed a statistically significant improvement from three months post-operatively onwards (all p < 0.001).

After two years whole blood metal ion levels were measured and chromosomal analysis was performed. The levels of all metal ions were elevated except vanadium. Levels of chromium, cobalt, molybdenum and titanium were significantly higher in patients who underwent bilateral THR compared with those undergoing unilateral THR (p < 0.001). Chromosomal analysis demonstrated both structural and aneuploidy mutations. There were significantly more breaks and losses than in the normal population (p < 0.001). There was no significant difference in chromosomal aberration between those undergoing unilateral and bilateral procedures (all analyses p ≥ 0.62).

The use of a CoM THR is effective clinically in the short-term, with no concerns, but the significance of high metal ion levels and chromosomal aberrations in the long-term remains unclear.

Cite this article: Bone Joint J 2013;95-B:1040–44.

Local recurrence along the biopsy track is a known complication of percutaneous needle biopsy of malignant musculoskeletal tumours. In order to completely excise the track with the tumour its identification is essential, but this becomes increasingly difficult over time. In an initial prospective study, 22 of 45 patients (48.8%) identified over a three-month period, treated by resection of a musculoskeletal tumour, had an unidentifiable biopsy site at operation, with identification statistically more difficult after 50 days. We therefore introduced the practice of marking the biopsy site with India ink. In all 55 patients undergoing this procedure, the biopsy track was identified pre-operatively (100%); this difference was statistically significant. We recommend this technique as a safe, easy and accurate means of ensuring adequate excision of the biopsy track.

Cite this article: Bone Joint J 2013;95-B:250–3.

We analysed whether a high body mass index (BMI) had a deleterious effect on outcome following autologous chondrocyte implantation (ACI) or matrix-carried autologous chondrocyte implantation (MACI) for the treatment of full-thickness chondral defects of the knee from a subset of patients enrolled in the ACI vs MACI trial at The Royal National Orthopaedic Hospital.

The mean Modified Cincinnati scores (MCS) were significantly higher (p < 0.001) post-operatively in patients who had an ideal body weight (n = 53; 20 to 24.9 kg/m²) than in overweight (n = 63; 25 to 30 kg/m²) and obese patients (n = 22; > 30 kg/m²). At a follow-up of two years, obese patients demonstrated no sustained improvement in the MCS. Patients with an ideal weight experienced significant improvements as early as six months after surgery (p = 0.007). In total, 82% of patients (31 of 38) in the ideal group had a good or excellent result, compared with 49% (22 of 45) of the overweight and 5.5% (one of 18) in the obese group (p < 0.001). There was a significant negative relationship between BMI and the MCS 24 months after surgery (r = -0.4, p = 0.001).

This study demonstrates that obese patients have worse knee function before surgery and experience no sustained benefit from ACI or MACI at two years after surgery. There was a correlation between increasing BMI and a lower MCS according to a linear regression analysis. On the basis of our findings patient selection can be more appropriately targeted.

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique used to treat osteochondral lesions in the knee. For larger osteochondral lesions (> 5 cm²) deeper than approximately 8 mm we have combined the use of two MACI membranes with impaction grafting of the subchondral bone. We report our results of 14 patients who underwent the ‘bilayer collagen membrane’ technique (BCMT) with a mean follow-up of 5.2 years (2 to 8). There were 12 men and two women with a mean age of 23.6 years (16 to 40). The mean size of the defect was 7.2 cm² (5.2 to 12 cm²) and were located on the medial (ten) or lateral (four) femoral condyles. The mean modified Cincinnati knee score improved from 45.1 (22 to 70) pre-operatively to 82.8 (34 to 98) at the most recent review (p < 0.05). The visual analogue pain score improved from 7.3 (4 to 10) to 1.7 (0 to 6) (p < 0.05). Twelve patients were considered to have a good or excellent clinical outcome. One graft failed at six years.

The BCMT resulted in excellent functional results and durable repair of large and deep osteochondral lesions without a high incidence of graft-related complications.

Patients with skeletal dysplasia are prone to developing advanced osteoarthritis of the knee requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure owing to the deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We retrospectively reviewed the outcome of 11 TKRs performed in eight patients with skeletal dysplasia at our institution using the Stanmore Modular Individualised Lower Extremity System (SMILES) custom-made rotating-hinge TKR. There were three men and five women with mean age of 57 years (41 to 79). Patients were followed clinically and radiologically for a mean of seven years (3 to 11.5). The mean Knee Society clinical and function scores improved from 24 (14 to 36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to 80) and 50 (22 to 74), respectively, at final follow-up. Four complications were recorded, including a patellar fracture following a fall, a tibial peri-prosthetic fracture, persistent anterior knee pain, and aseptic loosening of a femoral component requiring revision. Our results demonstrate that custom primary rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, with a satisfactory range of movement and improved function. It compensates for bony deformity and ligament deficiency and reduces the likelihood of corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than with primary TKR in the general population.

The best method of reconstruction after resection of malignant tumours of the tibial diaphysis is unknown. In the absence of any long-term studies analysing the results of intercalary endoprosthetic replacement, we present a retrospective review of 18 patients who underwent limb salvage using a tibial diaphyseal endoprosthetic replacement following excision of a malignant bone tumour. There were ten men and eight women with a mean age of 42.5 years (16 to 76). Mean follow-up was 58.5 months (20 to 141) for all patients and 69.3 months (20 to 141) for the 12 patients still alive. Cumulative patient survival was 59% (95% confidence interval (CI) 32 to 84) at five years. Implant survival was 63% (95% CI 35 to 90) at ten years. Four patients required revision to a proximal tibial replacement at a mean follow-up of 29 months (10 to 54). Complications included metastases in five patients, aseptic loosening in four, peri-prosthetic fracture in two, infection in one and local recurrence in one. The mean Musculoskeletal Tumor Society score and the mean Toronto Extremity Salvage Score were 23 (17 to 28) and 74% (53 to 91), respectively.

Although rates of complication and revision were high, custom-made tibial diaphyseal replacement following resection of malignant bone tumours enables early return to function and provides an attractive alternative to other surgical options, without apparent compromise of patient survival.

We describe 22 cases of bizarre parosteal osteochondromatous proliferation, or Nora’s lesion. These are surface-based osteocartilaginous lesions typically affecting the hands and feet. All patients were identified from the records of a regional bone tumour unit and were treated between 1985 and 2009. Nine lesions involved the metacarpals, seven the metatarsals, one originated from a sesamoid bone of the foot and five from long bones (radius, ulna, tibia, and femur in two). The mean age of the patients was 31.8 years (6 to 66), with 14 men and eight women. Diagnosis was based on the radiological and histological features. The initial surgical treatment was excision in 21 cases and amputation of a toe in one. The mean follow-up was for 32 months (12 to 162). Recurrence occurred in six patients (27.3%), with a mean time to recurrence of 49 months (10 to 120). Two of the eight patients with complete resection margins developed a recurrence (25.0%), compared with four of 14 with a marginal or incomplete resection (28.6%).

Given the potential surgical morbidity inherent in resection, our data suggest that there may be a role for a relatively tissue-conserving approach to the excision of these lesions.

Between 1997 and 2007, 68 consecutive patients underwent replacement of the proximal humerus for tumour using a fixed-fulcrum massive endoprosthesis. Their mean age was 46 years (7 to 87). Ten patients were lost to follow-up and 16 patients died. The 42 surviving patients were assessed using the Musculoskeletal Tumor Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS) at a mean follow-up of five years and 11 months (one year to ten years and nine months). The mean MSTS score was 72.3% (53.3% to 100%) and the mean TESS was 77.2% (58.6% to 100%).

Four of 42 patients received a new constrained humeral liner to reduce the risk of dislocation. This subgroup had a mean MSTS score of 77.7% and a mean TESS of 80.0%. The dislocation rate for the original prosthesis was 25.9; none of the patients with the new liner had a dislocation at a mean of 14.5 months (12 to 18).

Endoprosthetic replacement for tumours of the proximal humerus using this prosthesis is a reliable operation yielding good results without the documented problems of unconstrained prostheses. The performance of this prosthesis is expected to improve further with a new constrained humeral liner, which reduces the risk of dislocation.

Introduction: There is limited literature available on the use of metal prosthetic replacements for the treatment of non-traumatic lesions of the proximal radius. This study is a medium-term follow-up of implant survivor-ship and the functional outcome following insertion of metal proximal radius endoprostheses performed at the Royal National Orthopaedic Hospital.

Method: We present a series of six patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic pathologies. The patients included four females and two males, with a mean age of 39 years at the time of surgery. Their diagnoses included Ewing’s sarcoma, chondroblastoma, benign fibrous histiocytoma, radio-ulna synostosis and renal carcinoma metastases in two patients. Follow-up extended to 192 months with a mean of 76 months.

Results: During this time there were no complications with the prostheses, the most recent radiographs demonstrated secure fixation of the implants and none required revision. One patient developed posterior interosseuous nerve neuropraxia following surgery, which partially recovered, and another patient passed away as a result of disseminated metastatic renal cell carcinoma which was present pre-operatively. The patient with radio-ulna synostosis had a 25° fixed flexion deformity of the elbow post-operatively but good flexion, supination and pro-nation. All other patients had full ranges of movement at the elbow. Functional scores were assessed using the Mayo Elbow Performance Score with patients achieving a mean score of 86 (65 – 100) out of 100.

Discussion: The results of the use of proximal radial endoprostheses for treatment of non-traumatic lesions are encouraging with regards to survivorship of the implant and functional outcome of the elbow.

Introduction: The aim of this study is to investigate whether MoM implants result in more chromosome aberrations and increased blood metal ions post-operatively when compared to MoP implants.

Large head metal-on-metal articulating surfaces of the hip are being used in increasing numbers of patients for oncological purposes due to the increased stability and reduced dislocation rate. Recent studies have raised many concerns over possible genotoxicity of MoM implants.

Methods: This is a prospective study of patients who have undergone elective total hip replacement. Patients were randomised into two groups (MoP and MoM). Patients are reviewed pre-operatively (control group), at 3 months, 6 months, 1 year and 2 years post-operatively. On each occasion blood tests are taken to quantify metal ion levels (chromium, cobalt, titanium, nickel and vanadium) using HR-ICPMS and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hybridisation (FISH).

Results: 24 patients had MoP prosthesis and 29 a MoM. Cobalt and chromium concentration increased during the first 6 months in both MoM and MoP groups, in the MoM group the chromium levels were twice that of MoP group and 12x that of the preoperative samples. There was no difference with the levels of titanium, nickel and vanadium. Chromosome aberrations occurred in both groups. At 6 months both the MoM and MoP groups showed increase frequency of aneuploidy aberrations with further increases after one year. Structural damage in the form of translocations occurred in the MoM group after one year, but not in the MoP group.

Discussion: Results of this study show that the levels of chromium and cobalt are significantly higher in the MoM group compared to the MoP group. This corresponds to increases in chromosome aberrations between the groups particularly in aneuploidy and translocations present in the MoM group at 1 year.

Introduction: 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 tumours can metastasise. The FUS-CREB3L2 gene translocation 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.

Methods: We report the cytogenetic analysis of 29 LGFMS cases, and clinical outcomes of 21 patients treated surgically between 1998 and 2008 at our regional bone and soft-tissue tumour centre.

Results: The mean age was 45.4 years and mean follow-up 30.1 months. The most common tumour location was the lower limb. There were no cases of local recurrence or metastasis. Fifteen patients (52.2%) were FUS-CREB3L2 translocation-positive, suggesting either that translocation incidence in our series is lower than other studies, or that reverse-transcriptase polymerase chain reaction (PCR) is less sensitive than the literature suggests. Patients 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.

Discussion: 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. It is not necessary to perform wide excision, and marginal margins are adequate. Longer-term follow-up is required to elucidate differences in the long-term clinical outcome between translocation-positive and negative patients.

Introduction: Intramedullary cementless fixation of massive tumor prostheses was developed to combat the high incidence of aseptic loosening in a young population of tumor patients. Its use has also expanded to include reconstruction of failed major knee arthroplasty. Our system uses a hydroxyapatite coated titanium stem in conjunction with a hydroxyapatite collar to obtain fixation.

Methods: We present a series of 72 patients (34 females, 38 males) with a mean follow-up of six years (2 months – 14 years). The mean age at the time of surgery was 17 (5 – 77). Within this group, 51 patients had osteosarcomas, 10 had giant cell tumors, eight had Ewing’s sarcoma and one each had malignant fibrous histiocytoma, spindle cell sarcoma and failed total knee arthroplasty. Non-invasive and minimally invasive growing prostheses were used in 33 patients.

Results: Nine patients required revision of the prosthesis at a mean of 5.2 years; 5 for aseptic loosening and four for infection. Twelve patients died at a mean of 20 months (1 – 84) post-operatively. Radiological evidence demonstrated remodelling around both the stem and the collar. There was gap closure to the hydroxyapatite coated collar in cases where seating was not complete. Consistent loss of cortical bone around the mid-stem was noted in the first 12 months but remained stable beyond this time frame.

Discussion: This study highlights our experience with cementless distal femoral endosprostheses. We demonstrate good results with regard to revision rate, gap closure and osseointegration.

Introduction: Non-invasive expandable prostheses for limb salvage tumour surgery was first used in 2002 and has now been implanted in a series of 40 skeletally immature patients.

Method: Our review of these includes 24 distal femoral replacements, 5 proximal femoral replacements, 3 total femoral replacements and 8 proximal tibial replacements. These were used to treat 31 osteosarcomas, 7 Ewing’s sarcomas, 1 chondrosarcoma and 1 aneurysmal bone cyst. Patients had a mean age of 11.7 years (7–16). Follow-up extended to 88 months with a mean of 26.3 months.

Results: There has been 1 failure of the prosthesis gearbox which required revision surgery. 4 of the prostheses reached their maximum length and were successfully re-operated to exchange components of the prosthesis and resume lengthening. 3 patients had disseminated meta-static disease (1 being present before primary surgery) and another developed infection of the prosthesis that required an above-knee amputation. There have been 233 lengthenings overall with 1 patient requiring reversal on one occasion due to intractable pain; this pain rescinded 30 minutes after lengthening was reduced by 10mm. Otherwise lengthening was well tolerated despite the significant growth of the limbs: mean 21.2mm (0.5–84mm). At latest follow-up the mean Musculoskeletal Tumour Society score was 75% (26–93%).

Discussion: The results achieved are equivalent to our series of minimally invasive growers which require repeated surgery. Our non-invasive growing prostheses remain reliable and negate the need for recurrent operations, thus resulting in low infection rates. Our results remain encouraging up to 7 years after first use, maintaining leg-length equality and function.

Introduction: Massive endoprostheses are widely employed in limb salvage surgery for malignant bone tumours. Whilst joint preservation rather than replacement is usually attempted, cases arise where there is insufficient bone following tumour resection to allow adequate fixation of a joint sparing prosthesis.

Method: We report a series of four patients (aged 4–12), in which irradiated autologous bone was combined with distal femoral replacement in order to preserve the native hip joint.

Results: There were three cases of Osteosarcoma and one 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 were no cases of loosening or peri-prosthetic fracture.

Discussion: This is the first report of a new technique utilising irradiated autologous proximal femoral bone combined with distal femoral replacement in skeletally immature patients.

Introduction: 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 femoral physes in skeletally immature children.

Method: 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 unicortical screws positioned distal to the physis. In the female, these screws were removed 6 months post-op 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, post-operative assessments of leg lengths, bilaterally, were documented.

Results: 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.

Discussion: 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.

Introduction: 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.

Methods: A consecutive retrospective series of 100 patients with a histological diagnosis of chondrosarcoma made at a supra-regional bone tumour unit was reviewed. Twenty-one patients were excluded because 20 had only excision biopsy, due to radiological confidence in the diagnosis, and one had only the pre-operative biopsy on record, thus this series included 79 available cases. The remaining patients underwent a pre-operative needle biopsy.

Results: 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).

Discussion: From this series we conclude that accurate image-guided biopsy is a very useful adjunct in determining histological grade of chondrosarcoma and the subsequent treatment plan. At present, a multidisciplinary approach, comprising experienced Orthopaedic Surgeons, Radiologists and Pathologists offers the most reliable means of accurately diagnosing and grading chondrosarcoma of long bones.

Introduction: Alveolar soft part sarcoma (ASPS) is a soft tissue tumour found primarily in adolescents and young adults. It has an incidence of 0.5 – 1.0 % of all soft tissue sarcomas and a predilection for females. The lesion is inherently malignant and may occur throughout the body however, reports suggest they are predominantly detected in the anterior thigh. Symptoms include a painless slow-growing mass but ASPS can commonly present with brain or lung metastases due to the high vascularity of the lesion. Microscopically, cellular groups exist with centralised areas of necrosis, thus resulting in a pseudoalveolar appearance.

Methods: We identified six cases of histologically proven ASPS. The mean age was 28.5 years (21–36). Four patients were male. All patients had a primary presentation of a mass, two of which were painful. All patients, except one, presented within 8 months of the onset of symptoms (mean 3.8 months) with the other seeking medical advice only after 72 months. The location of the mass included the thigh in three patients and the triceps, soleus and retroperitoneal space in the others. Four patients underwent pre-operative diagnostic biopsies. Surgical excision was performed in all patients.

Results: The mean size of tumour was 9.4 x 9.4 x 6.3cm but there was no correlation between lesion size and duration of symptoms. The patient who presented late was found to have multiple lung metastases prior to surgery. Despite appropriate adjuvant therapy, three patients developed post-operative metastases at a mean of 5.2 months (1–24), two of which died along with the patient who presented with metastases at a mean of 2.6 years.

Discussion: This series demonstrates that this tumour may present as a painful mass. Despite early detection and appropriate treatment, ASPS remains a highly malignant neoplasm with a high associated mortality rate.

We have reviewed five adult patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic lesions. The patients had a mean age of 33.4 years (20 to 60) at the time of surgery and the mean follow-up was 7.6 years (0.8 to 16).

Following surgery, all elbows were clinically stable and there was 100% survivorship of the prosthesis. Evaluation of function was assessed clinically and by the Mayo Elbow Performance Score, achieving a mean of 86% (70 to 100).

Results at medium-term follow-up are encouraging with regards to elbow stability, implant survivorship and functional outcome.

Although bone and soft-tissue sarcomas are rare, early diagnosis and prompt referral to a specialised unit offers the best chance of a successful outcome both in terms of survival and surgical resection. This paper highlights the clinical and radiological features that might suggest the possibility of a bone or soft-tissue sarcoma and suggests a succinct management pathway for establishing whether a suspicious bone or soft-tissue lesion could be malignant.

Disarticulation of the hip in patients with high-grade tumours in the upper thigh results in significant morbidity. In patients with no disease of the proximal soft tissue a femoral stump may be preserved, leaving a fulcrum for movement and weight-bearing. We reviewed nine patients in whom the oncological decision would normally be to disarticulate, but who were treated by implantation of an endoprosthesis in order to create a functioning femoral stump. The surgery was undertaken for chondrosarcoma in four patients, pleomorphic sarcoma in three, osteosarcoma in one and fibrous dysplasia in one. At follow-up at a mean of 80 months (34 to 132), seven patients were alive and free from disease, one had died from lung metastases and another from a myocardial infarction. The mean functional outcome assessment was 50 (musculoskeletal tumor society), 50 and 60 (physical and mental Short-form 36 scores).

Implantation of an endoprosthesis into the stump in carefully selected patients allows fitting of an above-knee prosthesis and improves wellbeing and the functional outcome.

Segmental resection of malignant bone disease in the femoral diaphysis with subsequent limb reconstruction is a major undertaking. This is a retrospective review of 23 patients who had undergone limb salvage by endoprosthetic replacement of the femoral diaphysis for a primary bone tumour between 1989 and 2005.

There were 16 males and seven females, with a mean age of 41.3 years (10 to 68). The mean overall follow-up was for 97 months (3 to 240), and 120 months (42 to 240) for the living patients. The cumulative patient survival was 77% (95% confidence interval 63% to 95%) at ten years. Survival of the implant, with failure of the endoprosthesis as an endpoint, was 85% at five years and 68% (95% confidence interval 42% to 92%) at ten years. The revision rate was 22% and the overall rate of re-operation was 26%. Complications included deep infection (4%), breakage of the prosthesis (8%), periprosthetic fracture (4%), aseptic loosening (4%), local recurrence (4%) and metastases (17%). The 16 patients who retained their diaphyseal endoprosthesis had a mean Musculoskeletal Tumour Society score of 87% (67% to 93%). They were all able to comfortably perform most activities of daily living.

Femoral diaphyseal endoprosthetic replacement is a viable option for reconstruction following segmental resection of malignant bone disease. It allows immediate weight-bearing, is associated with a good long-term functional outcome, has an acceptable complication and revision rate and, most importantly, does not appear to compromise patient survival.

Elastofibroma dorsi is an uncommon, benign, slow-growing soft-tissue tumour of uncertain aetiology. It classically presents as an ill-defined mass at the inferior pole of the scapula with symptoms which include swelling, discomfort, snapping, stiffness and occasionally pain.

We report the symptoms, function and outcome after treatment of 21 elastofibromas in 15 patients. All were diagnosed by MRI and early in the series four also underwent CT-guided biopsy to confirm the diagnosis. In all, 18 tumours were excised and three were observed. After excision, the mean visual analogue score for pain decreased from 4.6 (0 to 10) pre-operatively to 2.4 (0 to 8) post-operatively (p = 0.04). The mean shoulder function, at a mean follow-up of 4.2 years (3 months to 16 years), was 78.1% (30 to 100) using the Stanmore percentage of normal shoulder assessment scoring system. The mean range of forward flexion improved from 135° (70° to 180°) to 166° (100° to 180°) after excision (p = 0.005). In four patients a post-operative haematoma formed; one required evacuation. Three patients developed a post-operative seroma requiring needle aspiration and one developed a superficial infection which was treated with antibiotics.

Our findings support previous reports suggesting that a pre-operative tissue diagnosis is not necessary in most cases since the lesion can be confidently diagnosed by MRI, when interpreted in the light of appropriate clinical findings. Surgical excision in symptomatic patients, is helpful.

It has been suggested that elastofibroma is caused by a local tissue reaction and is not a true neoplastic process. A strong association has been noted between elastofibroma and repetitive use of the shoulder, which is supported by our findings.

Smoking is known to have an adverse effect on wound healing and musculoskeletal conditions. This case-controlled study looked at whether smoking has a deleterious effect in the outcome of autologous chondrocyte implantation for the treatment of full thickness chondral defects of the knee.

The mean Modified Cincinatti Knee score was statistically significantly lower in smokers (n = 48) than in non-smokers (n = 66) both before and after surgery (p < 0.05). Smokers experienced significantly less improvement in the knee score two years after surgery (p < 0.05). Graft failures were only seen in smokers (p = 0.016). There was a strong negative correlation between the number of cigarettes smoked and the outcome following surgery (Pearson’s correlation coefficient −0.65, p = 0.004).

These results suggest that patients who smoke have worse pre-operative function and obtain less benefit from this procedure than non-smokers. The counselling of patients undergoing autologous chondrocyte implantation should include smoking, not only as a general cardiopulmonary risk but also because poorer results can be expected in smokers following this procedure.

We undertook a retrospective review of 33 patients who underwent total femoral endoprosthetic replacement as limb salvage following excision of a malignant bone tumour. In 22 patients this was performed as a primary procedure following total femoral resection for malignant disease. Revision to a total femoral replacement was required in 11 patients following failed segmental endoprosthetic or allograft reconstruction. There were 33 patients with primary malignant tumours, and three had metastatic lesions. The mean age of the patients was 31 years (5 to 68). The mean follow-up was 4.2 years (9 months to 16.4 years). At five years the survival of the implants was 100%, with removal as the endpoint and 56% where the endpoint was another surgical intervention. At five years the patient survival was 32%. Complications included dislocation of the hip in six patients (18%), local recurrence in three (9%), peri-prosthetic fracture in two and infection in one. One patient subsequently developed pulmonary metastases. There were no cases of aseptic loosening or amputation. Four patients required a change of bushings. The mean Musculoskeletal Tumour Society functional outcome score was 67%, the mean Harris Hip Score was 70, and the mean Oxford Knee Score was 34.

Total femoral endoprosthetic replacement can provide good functional outcome without compromising patient survival, and in selected cases provides an effective alternative to amputation.

Endoprosthetic replacement of the distal tibia and ankle joint for a primary bone tumour is a rarely attempted and technically challenging procedure. We report the outcome of six patients treated between 1981 and 2007. There were four males and two females, with a mean age of 43.5 years (15 to 75), and a mean follow-up of 9.6 years (1 to 27). No patient developed a local recurrence or metastasis. Two of the six went on to have a below-knee amputation for persistent infection after a mean 16 months (1 to 31). The four patients who retained their endoprosthesis had a mean musculoskeletal tumour society score of 70% and a mean Toronto extremity salvage score of 71%. All were pain free and able to perform most activities of daily living in comfort.

A custom-made endoprosthetic replacement of the distal tibia and ankle joint is a viable treatment option for carefully selected patients with a primary bone tumour. Patients should, however, be informed of the risk of infection and the potential need for amputation if this cannot be controlled.

This paper describes the preliminary results of a proximal tibial endoprosthesis which spares the knee joint and enables retention of the natural articulation by replacing part of the tibial metaphysis and diaphysis. In eight patients who had a primary malignant bone tumour of the proximal tibia, the distal stem, which had a hydroxyapatite-coated collar to improve fixation, was cemented into the medullary canal. The proximal end had hydroxyapatite-coated extracortical plates which were secured to the remaining proximal tibial metaphysis using cortical screws. The mean age of the patients at operation was 28.9 years (8 to 43) and the mean follow-up was for 35 months (4 to 48). The mean Musculoskeletal Tumour Society score was 79% (57% to 90%), the mean Oxford Knee score was 40 points of 48 (36 to 46) and the mean knee flexion was 112° (100° to 120°). In one patient, revision to a below-knee amputation through the prosthesis was required because of recurrence of the tumour. Another patient sustained a periprosthetic fracture which healed with a painful malunion. This was revised to a further endoprosthesis which replaced the knee.

In the remaining six patients the prosthesis allowed preservation of the knee joint with good function and no early evidence of loosening. Further follow-up is required to assess the longevity of these prostheses.

We describe the application of a non-invasive extendible endoprosthetic replacement in skeletally-mature patients undergoing revision for failed joint replacement with resultant limb-length inequality after malignant or non-malignant disease. This prosthesis was developed for tumour surgery in skeletally-immature patients but has now been adapted for use in revision procedures to reconstruct the joint or facilitate an arthrodesis, replace bony defects and allow limb length to be restored gradually in the post-operative period.

We record the short-term results in nine patients who have had this procedure after multiple previous reconstructive operations. In six, the initial reconstruction had been performed with either allograft or endoprosthetic replacement for neoplastic disease and in three for non-neoplastic disease. The essential components of the prosthesis are a magnetic disc, a gearbox and a drive screw which allows painless lengthening of the prosthesis using the principle of electromagnetic induction. The mean age of the patients was 37 years (18 to 68) with a mean follow-up of 34 months (12 to 62). They had previously undergone a mean of six (2 to 14) open procedures on the affected limb before revision with the non-invasive extendible endoprosthesis.

The mean length gained was 56 mm (19 to 107) requiring a mean of nine (3 to 20) lengthening episodes performed in the outpatient department. There was one case of recurrent infection after revision of a previously infected implant and one fracture of the prosthesis after a fall. No amputations were performed. Planned exchange of the prosthesis was required in three patients after attainment of the maximum lengthening capacity of the implant. There was no failure of the lengthening mechanism. The Mean Musculoskeletal Tumour Society rating score was 22 of 30 available points (18 to 28).

The use of a non-invasive extendible endoprosthesis in this manner provided patients with good functional results and restoration of leg-length equality, without the need for multiple open lengthening procedures.

Chondral damage to the knee is common and, if left untreated, can proceed to degenerative osteoarthritis. In symptomatic patients established methods of management rely on the formation of fibrocartilage which has poor resistance to shear forces. The formation of hyaline or hyaline-like cartilage may be induced by implanting autologous, cultured chondrocytes into the chondral or osteochondral defect.

Autologous chondrocyte implantation may be used for full-thickness chondral or osteochondral injuries which are painful and debilitating with the aim of replacing damaged cartilage with hyaline or hyaline-like cartilage, leading to improved function. The intermediate and long-term functional and clinical results are promising.

We provide a review of autologous chondrocyte implantation and describe our experience with the technique at our institution with a mean follow-up of 32 months (1 to 9 years).

The procedure is shown to offer statistically significant improvement with advantages over other methods of management of chondral defects.

We report a case which highlights the progression of osteofibrous dysplasia to adamantinoma and questions whether intralesional curettage is the appropriate treatment. The role of a joint-sparing massive endoprosthesis using cortical fixation is demonstrated and we describe a unique biomedical design which resulted in the manufacture of an end cap to allow amputation through a custom-made proximal tibial replacement, rather than an above-knee amputation following recurrence.

We treated 98 patients with peri-acetabular tumours by resection and reconstruction with a custom-made pelvic endoprosthesis. The overall survival of the patients was 67% at five years, 54% at ten years and 51% at 30 years. One or more complications occurred in 58.1% of patients (54), of which infection was the most common, affecting 30% (28 patients). The rate of local recurrence was 31% (29 patients) after a mean follow-up of 71 months (11 to 147). Dislocation occurred in 20% of patients (19). Before 1996 the rate was 40.5% (17 patients) but this was reduced to 3.9% (two patients) with the introduction of a larger femoral head. There were six cases of palsy of the femoral nerve with recovery in only two. Revision or excision arthroplasty was performed in 23.7% of patients (22), principally for uncontrolled infection or aseptic loosening. Higher rates of death, infection and revision occurred in men.

This method of treatment is still associated with high morbidity. Patients should be carefully selected and informed of this pre-operatively.

Aims: he purpose of this study was to determine whether autologous chondrocyte implantation (ACI) in patients with articular cartilage defects of the knee resulted in patients returning to pre-injury levels of work and physical activities.

Methods: 133 consecutive patients from January 2001 to December 2002 underwent ACI at our institution. A telephone and postal questionnaire was conducted to ascertain a detailed occupational and leisure activity profile in this cohort of patients. For each job held for at least 2 months, we asked whether an average working day had involved any of the ten specified physical activities. Similarly, for each sport that had been played more than 5 times a year, we asked the age the sporting activities had began and whether they were able to return to these sports after surgery. Occupation for each patient was given a 3 digit code according to the Standard Occupational Classification System 2000 and hence determined whether the work performed was manual or non-manual.

Results: 97 patients responded to the questionnaire. There were 53 females and 44 males and the mean age at the time of operation was 34.5 (range 14 to 49). Category 6 (Personal Services Occupations) was the most common occupation pre-operatively, whereas category 4 (Administrative and Secretarial Occupations) was the most common post-operatively. 7% of patients’ work involved kneeling or squatting and this figure rose to 12%, 4 years following surgery. 42% of patients had to make some form of modification to their work (usually less physical or more office based). 47% of patients were able to return to at least one of the sports they played pre-injury.

Conclusion: This is the first study to demonstrate that patients are able to return to work and resume sporting activity following autologous chondrocyte implantation.

Aims: The main purpose of this study was to evaluate hemiplevis replacements in patients with periacetabular tumours in terms of the functional results and implant survivorship of the prosthesis. The second aim was to evaluate the complications and how they might be prevented in the future.

Methods: Case notes, hospital databases and radiographs were reviewed in 51 patients treated in a 16 year period with a custom made hemipelvis replacement (Stanmore Implants Worldwide). There were 13 deaths and 4 were lost to follow up. Of the remaining 34 patients there were 18 males and 16 females with a mean age of 48.6 (range 14 – 71).

Results: At a mean follow-up of 78 months (range 7 – 204), 70% of patients were still alive and the most common diagnosis was chondrosarcoma (17 cases). There were 2 cases of prosthesis failure and 22 of the 34 patients had one or more complications (12 cases of infection (8 deep and 4 superficial), 4 nerve palsies, 2 dislocations and 7 others). 13 patients had to have a second operation. The mean MSTS score was 63.8% and the TESS score was 59.8%

Conclusion: Infection was the most common complication and was the most significant reason for reoperation. This method of reconstruction is associated with a high morbidity rate and should be performed only at specialist centres, but the functional and oncological outcomes are satisfactory.

Background: Advances in adjuvant and neoadjuvant therapies have rendered many tumours that previously necessitated amputation amenable to limb salvage procedures. However, a significant proportion of tumours are still treated by hindquarter amputation in an attempt to cure the patient, or to reduce the tumour load. This tends to be lengthy, mutilating and is associated with high morbidity and poor survivorship.

Aims: To review the survivorship, quality of life and functional assessment following hindquarter amputations performed in this centre in the last 10 years.

Methods: This was a retrospective study of 51 consecutive patients who had hindquarter amputations for tumours between 1996 to 2006. Available patients were evaluated using contemporary functional outcome assessments (Musculoskeletal Society Tumour Score, Toronto Extremity Salvage Score, SF36).

Results: Fifty-one patients (31 males, 20 females) had palliative(8) or curative hindquarter amputations(43) for Chondrosarcoma(18), Malignant Fibrous Histiocytoma(6), Osteosarcoma(4) and other sarcoma sub-types(23). The mean age was 50.7 years (range 24–78). The mean duration of symptoms until referral was 5.2 months, the mean time from referral to tissue diagnosis was 16.2 days (range 2–80) and the time from confirmed histological diagnosis to surgery was 39.2 days (range 2–190) on average. Significant complications included phantom limb pain(15), wound problems(24), urinary problems(6), cardiopulmonary events(5) and erectile dysfunction(3). 33 of the 51 patients have passed away, with a mean survival postoperatively of 10.7 months (range 2–43), with carcinomatosis the main cause of death. The mean cumulative survival following hindquarter amputation in this hospital is 17.3 months.

Conclusions: Patients with no metastasis and clear margins at amputation had a better cumulative survival rate. Therefore the decision to proceed for hindquarter amputation to achieve a curative resection is justified but has to be weighed up against the associated significant complications, morbidity and functional deterioration.

Dedifferentiated chordoma is a rare and aggressive variant of the conventional tumour in which an area undergoes transformation to a high-grade lesion, typically fibrous histiocytoma, fibrosarcoma, and rarely, osteosarcoma or rhabdomyosarcoma. The dedifferentiated component dictates overall survival, with smaller areas of dedifferentiation carrying a more favourable prognosis. Although it is more commonly diagnosed in recurrences and following radiotherapy, there have been a few reports of spontaneous development. We describe four such cases, which were diagnosed de novo following primary excision, and discuss the associated clinical and radiological features.

We describe two cases of osteochondritis dissecans (OCD) affecting both femoral condyles in the same knee. The patients presented with recurrent episodes of pain and swelling, but these were initially thought to be ‘growing pains’. Eventually, a delayed diagnosis of bicondylar OCD was established and both patients were referred for further management. After assessing the extent of the disease on MRI, matrix-induced autologous chondrocyte implantation was performed to treat the defects of the lateral condyle in each case, with a plan to address the medial defects at a later stage. Proposed theories on the aetiology of the condition and available methods of treatment are discussed. A diagnosis of OCD should be considered in young patients with persistent knee pain and effusions, and MRI is the investigation of choice for early detection.

We studied the influence of soft-tissue releases and soft-tissue balance on the outcome of 526 total knee replacements one year after operation. The surgery had been performed by seven surgeons in five centres in the United Kingdom between October 1999 and December 2002. Balancing was carried out by five surgeons using spacers and trials and by two surgeons using a ‘balancer’ instrument. All the surgeons assessed the adequacy of their releases by taking measurements with the balancer after soft-tissue release before implanting the components. Independent observers collected the Oxford knee scores and applied the American Knee Society functional and knee scores as well as recording the range of movement of the replaced knee. These were compared with the pre-operative scores and the extent of the releases.

We found differences in outcomes between minimal and extensive releases and between balanced and imbalanced knees.

Knees requiring extensive soft-tissue releases showed greater change in the short-term clinical outcome without increased complications and achieved similar results at one year compared with those with less deformity pre-operatively which had required less soft-tissue release. Balancing an imbalanced knee improved the short-term knee outcome.

We have managed 27 patients (16 women and 11 men) with a mean age of 68.4 years (50 to 84), with failed total hip replacement and severe proximal femoral bone loss by revision using a distal fix/proximal wrap prosthesis. The mean follow-up was for 55.3 months (25 to 126). The mean number of previous operations was 2.2 (1 to 4). The mean Oxford hip score decreased from 46.2 (38 to 60) to 28.5 (17 to 42) (paired t-test, p < 0.001) and the mean Harris Hip score increased from 30.4 (3 to 57.7) to 71.7 (44 to 99.7) (paired t-test, p < 0.001). There were two dislocations, and in three patients we failed to eradicate previous infection. None required revision of the femoral stem.

This technique allows instant distal fixation while promoting biological integration and restoration of bone stock. In the short term, the functional outcome is encouraging and the complication rates acceptable in this difficult group of patients.

Four patients who developed malignant synovial tumours are described; one with chondromatosis developed a synovial chondrosarcoma and three with pigmented villonodular synovitis developed malignant change. The relevant literature is discussed.

Between 1988 and 2006, 18 patients had a custom-made endoprosthetic replacement of the distal humerus for bone tumours at our institution. There were 11 primary malignant neoplasms, six secondary deposits, and one benign aggressive tumour. The mean follow-up was for 4.4 years (1 to 18.2). Complications occurred in nine patients and included aseptic loosening in three (16.6%), local recurrence in two (11%), infection in two (11%), neuropraxia of the radial nerve in one (5.5%) and a peri-prosthetic fracture in one (5.5%). Excision was inadequate in four patients (22%), all of which developed local recurrence and/or metastases. There were seven deaths from the primary disease after a mean of 2.3 years (1 to 5), one of whom had an above-elbow amputation for local recurrence seven months before death. The remaining six had satisfactory elbow function at their last follow-up. The 11 living patients were evaluated using the Musculoskeletal Tumour Society and Toronto Extremity Salvage scoring systems. The mean scores achieved were 76% (67% to 87%) and 73% (59% to 79%), respectively. Overall, 17 of 18 patients had significant improvement in the degree of their pain following operation.

Custom-made endoprosthetic reconstruction of the elbow for bone tumours is a viable treatment in carefully selected patients. It maintains satisfactory function and provides good pain relief.

The weight-bearing status of articular cartilage has been shown to affect its biochemical composition. We have investigated the topographical variation of sulphated glycosaminoglycan (GAG) relative to the DNA content of the chondrocyte in human distal femoral articular cartilage.

Paired specimens of distal femoral articular cartilage, from weight-bearing and non-weight-bearing regions, were obtained from 13 patients undergoing above-knee amputation. After papain enzyme digestion, spectrophotometric GAG and fluorometric DNA assays assessed the biochemical composition of the samples. The results were analysed using a paired t-test.

Although there were no significant differences in cell density between the regions, the weight-bearing areas showed a significantly higher concentration of GAG relative to DNA when compared with non-weight-bearing areas (p = 0.02).

We conclude that chondrocytes are sensitive to their mechanical environment, and that local loading conditions influence the metabolism of the cells and hence the biochemical structure of the tissue.

We used a knee-sparing distal femoral endoprosthesis in young patients with malignant bone tumours of the distal femur in whom it was possible to resect the tumour and to preserve the distal femoral condyles. The proximal shaft of the endoprosthesis had a coated hydroxyapatite collar, while the distal end had hydroxyapatite-coated extracortical plates to secure it to the small residual femoral condylar fragment. We reviewed the preliminary results of this endoprosthesis in eight patients with primary bone tumours of the distal femur. Their mean age at surgery was 17.years (14 to 21). The mean follow-up was 24 months (20 to 31). At final follow-up the mean flexion at the knee was 102° (20° to 120°) and the mean Musculoskeletal Tumour Society score was 80% (57% to 96.7%).

There was excellent osteointegration at the prosthesis-proximal bone interface with formation of new bone around the hydroxyapatite collar. The prosthesis allowed preservation of the knee and achieved a good functional result. Formation of new bone and remodelling at the interface make the implant more secure. Further follow-up is required to determine the long-term structural integrity of the prosthesis.

Osteofibrous dysplasia is an unusual developmental condition of childhood, 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 and some authors believe that they are part of one histological process.

We retrospectively reviewed 16 patients who were diagnosed as having osteofibrous dysplasia initially or on the final histological examination. Their management was diverse, depending on the severity of symptoms and the extent of the lesion. Definitive (extraperiosteal) surgery was localised ‘shark-bite’ excision for small lesions in five patients. Extensive lesions were treated by segmental excision and fibular autograft in six patients, external fixation and bone transport in four and proximal tibial replacement in one. One patient who had a fibular autograft required further excision and bone transport for recurrence. Six initially underwent curettage and all had recurrence. There were no recurrences after localised extraperiosteal excision or bone transport. There were three confirmed cases of adamantinoma.

The relevant literature is reviewed. We recommend extraperiosteal excision in all cases of osteofibrous dysplasia, with segmental excision and reconstruction in more extensive lesions.

We report our early experience with the use of a non-invasive distal femoral expandable endoprosthesis in seven skeletally immature patients with osteosarcoma of the distal femur. The patients had a mean age of 12.1 years (9 to 15) at the time of surgery. The prosthesis was lengthened at appropriate intervals in outpatient clinics, without anaesthesia, using the principle of electromagnetic induction. The patients were functionally evaluated using the Musculoskeletal Tumour Society scoring system. The mean follow-up was 20.2 months (14 to 30). The prostheses were lengthened by a mean of 25 mm (4.25 to 55) and maintained a mean knee flexion of 110° (100° to 120°). The mean Musculoskeletal Tumour Society score was 68% (11 to 29). Complications developed in two patients; one developed a flexion deformity of 25° at the knee joint, which was subsequently overcome and one died of disseminated disease. The early results from patients treated with this device have been encouraging. The implant avoids multiple surgical procedures, general anaesthesia and assists in maintaining leg-length equality.