Pigmented villonodular synovitis of the knee: A retrospective analysis of 214 cases at a UK tertiary referral centre.

AIMS: Pigmented villonodular synovitis (PVNS) is a rare, locally aggressive and potentially recurrent synovial disease. We present the largest single-centre experience of knee PVNS. Our aim was to evaluate our tertiary hospital's experience in the management of knee PVNS. PATIENTS AND METHODS: Retrospective data collection of consecutive cases of knee PVNS from 2002 to 2015. RESULTS: In total, 214 cases of knee PVNS were identified which represented 53.4% of all PVNS (12.1% were recurrent at presentation). 100 were localised PVNS (LPVNS), 114 diffuse PVNS (DPVNS) and two malignant PVNS. Knee PVNS was more likely to occur in females with a mean age of 39. Following surgery, 47.6% had recurrence with DPVNS as opposed to 8.6% with LPVNS. In LPVNS, there was no significant difference in recurrence between open and arthroscopic synovectomy (8.7% vs 9.1%, P>0.05). However, in DPVNS, there was a significantly higher risk of recurrence with arthroscopic compared to open synovectomy (83.3% vs 44.8%, RR=1.86 95% CI 1.32-2.62, P=0.0004). CONCLUSION: PVNS can be difficult to treat. We found no difference in local recurrence rates between open and arthroscopic treatment of LPVNS but significantly increased rates of recurrence for DPVNS following arthroscopic treatment. We would therefore recommend open synovectomy for DPVNS.

Metal-on-polyethylene versus metal-on-metal bearing surfaces in total hip arthroplasty: a prospective randomised study investigating metal ion levels and chromosomal aberrations in peripheral lymphocytes.

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 (R(2) = 0.90016), but this was not as strong for Co (R(2) = 0.68991). In the MoP group, the analysis revealed a poor relationship between Cr levels and the total chromosomal aberration indices (R(2) = 0.23908) but a slightly stronger relationship for Co (R(2) = 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.

How safe is curettage of low-grade cartilaginous neoplasms diagnosed by imaging with or without pre-operative needle biopsy?

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.

Uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses: up to 18 years' follow-up.

We reviewed the outcome of 69 uncemented, custom-made, distal femoral endoprosthetic replacements performed in 69 patients between 1994 and 2006. There were 31 women and 38 men with a mean age at implantation of 16.5 years (5 to 37). All procedures were performed for primary malignant bone tumours of the distal femur. At a mean follow-up of 124.2 months (4 to 212), 53 patients were alive, with one patient lost to follow-up. All nine implants (13.0%) were revised due to aseptic loosening at a mean of 52 months (8 to 91); three implants (4.3%) were revised due to fracture of the shaft of the prosthesis and three patients (4.3%) had a peri-prosthetic fracture. Bone remodelling associated with periosteal cortical thinning adjacent to the uncemented intramedullary stem was seen in 24 patients but this did not predispose to failure. All aseptically loose implants in this series were diagnosed to be loose within the first five years. The results from this study suggest that custom-made uncemented distal femur replacements have a higher rate of aseptic loosening compared to published results for this design when used with cemented fixation. Loosening of uncemented replacements occurs early indicating that initial fixation of the implant is crucial.

Autologous chondrocyte implantation for osteochondral lesions in the knee using a bilayer collagen membrane and bone graft: a two- to eight-year follow-up study.

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique used to treat osteochondral lesions in the knee. For larger osteochondral lesions (> 5 cm(2)) 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 cm(2) (5.2 to 12 cm(2)) 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.

Custom rotating-hinge primary total knee arthroplasty in patients with skeletal dysplasia.

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 medium-term results of the Stanmore non-invasive extendible endoprosthesis in the treatment of paediatric bone tumours.

In skeletally immature patients, resection of bone tumours and reconstruction of the lower limb often results in leg-length discrepancy. The Stanmore non-invasive extendible endoprosthesis, which uses electromagnetic induction, allows post-operative lengthening without anaesthesia. Between 2002 and 2009, 55 children with a mean age of 11.4 years (5 to 16) underwent reconstruction with this prosthesis; ten patients (18.2%) died of disseminated disease and one child underwent amputation due to infection. We reviewed 44 patients after a mean follow-up of 41.2 months (22 to 104). The mean Musculoskeletal Tumor Society score was 24.7 (8 to 30) and the Toronto Extremity Salvage score was 92.3% (55.2% to 99.0%). There was no local recurrence of tumour. Complications developed in 16 patients (29.1%) and ten (18.2%) underwent revision. The mean length gained per patient was 38.6 mm (3.5 to 161.5), requiring a mean of 11.3 extensions (1 to 40), and ten component exchanges were performed in nine patients (16.4%) after attaining the maximum lengthening capacity of the implant. There were 11 patients (20%) who were skeletally mature at follow-up, ten of whom had equal leg lengths and nine had a full range of movement of the hip and knee. This is the largest reported series using non-invasive extendible endoprostheses after excision of primary bone tumours in skeletally immature patients. The technique produces a good functional outcome, with prevention of limb-length discrepancy at skeletal maturity.

Intercalary diaphyseal endoprosthetic reconstruction for malignant tibial bone tumours.

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.

Bizarre parosteal osteochondromatous proliferation of bone: clinical management of a series of 22 cases.

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.

Use of metal proximal radial endoprostheses for treatment of non-traumatic disorders: a case series.

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.

Femoral diaphyseal endoprosthetic reconstruction after segmental resection of primary bone tumours.

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: management, outcome and review of the literature.

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 degrees (70 degrees to 180 degrees ) to 166 degrees (100 degrees to 180 degrees ) 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.

Custom-made hinged spacers in revision knee surgery for patients with infection, bone loss and instability.

Polymethyl methacrylate spacers are commonly used during staged revision knee arthroplasty for infection. In cases with extensive bone loss and ligament instability, such spacers may not preserve limb length, joint stability and motion. We report a retrospective case series of 19 consecutive patients using a custom-made cobalt chrome hinged spacer with antibiotic-loaded cement. The "SMILES spacer" was used at first-stage revision knee arthroplasty for chronic infection associated with a significant bone loss due to failed revision total knee replacement in 11 patients (58%), tumour endoprosthesis in four patients (21%), primary knee replacement in two patients (11%) and infected metalwork following fracture or osteotomy in a further two patients (11%). Mean follow-up was 38 months (range 24-70). In 12 (63%) patients, infection was eradicated, three patients (16%) had persistent infection and four (21%) developed further infection after initially successful second-stage surgery. Above knee amputation for persistent infection was performed in two patients. In this particularly difficult to treat population, the SMILES spacer two-stage technique has demonstrated encouraging results and presents an attractive alternative to arthrodesis or amputation.

Outcome of intralesional curettage for low-grade chondrosarcoma of long bones.

BACKGROUND: Different treatment strategies for low-grade chondrosarcomas are reported in the literature with variable outcomes. The aim of this study was to assess the oncological and functional outcomes associated with intralesional curettage and cementation of the lesion as a treatment strategy. PATIENTS AND METHODS: We performed a retrospective review of 39 consecutive patients with intramedullary low-grade chondrosarcoma of long bones treated by intralesional curettage and cementation at our institution between 1999 and 2005. RESULTS: There were 10 males and 29 females with a mean age of 55.5 years (32-82), and a mean follow-up of 5.1 years (3-8.7). Local recurrence occurred in two patients (5%) within the first two years following index surgery. Both were treated by re-curettage and cementation of the resultant defects. A second local recurrence developed a year later in one of these two patients, for which a further curettage followed by local liquid nitrogen treatment was performed. Overall, there were no cases of post-operative complications or metastases. The patients were assessed using the Musculoskeletal Tumour Society scoring system (MSTS) to determine limb function. The average score achieved was 94% (79-100%). CONCLUSION: Intralesional curettage is an effective treatment strategy for low-grade intramedullary chondrosarcoma of long bones, with excellent oncological and functional results. Careful case selection with stringent clinical and radiographic follow-up is recommended.

Dedifferentiated chordoma: a report of four cases arising 'de novo'.

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.

The use of massive endoprostheses for the treatment of bone metastases.

Purpose. We report a series of 58 patients with metastatic bone disease treated with resection and endoprosthetic reconstruction over a five-year period at our institution. Introduction. The recent advances in adjuvant and neoadjuvant therapy in cancer treatment have resulted in improved prognosis of patients with bone metastases. Most patients who have either an actual or impending pathological fracture should have operative stabilisation or reconstruction. Endoprosthetic reconstructions are indicated in patients with extensive bone loss, failed conventional reconstructions, and selected isolated metastases. Methods and Results. We identified all patients who were diagnosed with metastatic disease to bone between 1999 and 2003. One hundred and seventy-one patients were diagnosed with bone metastases. Metastatic breast and renal cancer accounted for 84 lesions (49%). Fifty-eight patients with isolated bone metastasis to the appendicular skeleton had an endoprosthetic reconstruction. There were 28 males and 30 females. Twelve patients had an endoprosthesis in the upper extremity and 46 patients had an endoprosthesis in the lower extremity. The mean age at presentation was 62 years (24 to 88). At the time of writing, 19 patients are still alive, 34 patients have died, and 5 have been lost to follow up. Patients were followed up and evaluated using the musculoskeletal society tumour score (MSTS) and the Toronto extremity salvage score (TESS). The mean MSTS was 73% (57% to 90%) and TESS was 71% (46% to 95%). Mean follow-up was 48.2 months (range 27 to 82 months) and patients died of disease at a mean of 22 months (2 to 51 months) from surgery. Complications included 5 superficial wound infections, 1 aseptic loosening, 4 dislocations, 1 subluxation, and 1 case, where the tibial component of a prosthesis rotated requiring open repositioning. Conclusions. We conclude that endoprosthetic replacement for the treatment of isolated bone metastases is a reliable method of limb reconstruction in selected cases. It is associated with low complication and failure rates in our series, and achieves the aims of restoring function, allowing early weight bearing and alleviating pain.

Large osteoarthritic cyst presenting as soft tissue tumour - a case report.

Large osteoarthritic cysts can sometimes be difficult to distinguish from primary osseous and soft tissue tumours. We present such a case involving a cyst arising from the hip joint and eroding the acetabulum which presented as a soft tissue malignancy referred to a tertiary bone and soft tissue tumour centre. We discuss the diagnostic problems it may pose, and present a literature review of the subject.

The swing procedure for pelvic ring reconstruction following tumour excision.

AIM: High grade periacetabular osteosarcomas extending to the sacro-iliac region present a difficult management problem. We describe our experience of the swing procedure as a method of limb salvage. METHOD: The procedure was performed on three patients with stage II B osteosarcoma. RESULTS: Functional outcome was poor in all three with a mean Musculoskeletal Tumor Society score of 29% (27-30) at last review. All three developed local recurrence and one developed pulmonary metastases. The mean disease free interval post-operatively was 4.7 months (4-6) and they died of their disease at a mean of 10 months (5-16). CONCLUSIONS: This form of limb salvage is technically demanding and carries a high morbidity. Functional outcome is poor and the prognosis for this group of patients is not improved by surgery. Alternative treatment options are discussed.