Custom-made rotating hinge total knee replacement in a patient with congenital tibial deficiency avoids the need for amputation.

We report a unique case of a patient with type 2 congenital tibial deficiency and disabling knee osteoarthritis in whom a custom-made rotating hinge knee replacement was successfully performed, allowing continued mobilisation with a below-knee prosthesis, thereby avoiding the need for an above-knee amputation. Level of evidence Therapeutic study, Level IV.

Potential therapeutic targets for chordoma: PI3K/AKT/TSC1/TSC2/mTOR pathway.

Chordomas are radio- and chemo-resistant tumours and metastasise in as many as 40% of patients. The aim of this study was to identify potential molecular targets for the treatment of chordoma. In view of the reported association of chordoma and tuberous sclerosis complex syndrome, and the available therapeutic agents against molecules in the PI3K/AKT/TSC1/TSC2/mTOR pathway, a tissue microarray of 50 chordoma cases was analysed for expression of active molecules involved in this signalling pathway by immunohistochemistry and a selected number by western blot analysis. Chordomas were positive for p-AKT (92%), p-TSC2 (96%), p-mTOR (27%), total mTOR (75%), p-p70S6K (62%), p-RPS6 (22%), p-4E-BP1 (96%) and eIF-4E (98%). Phosphatase and tensin homologue deleted on chromosome 10 expression was lost in 16% of cases. Mutations failed to be identified in PI3KCA and RHEB1 in the 23 cases for which genomic DNA was available. Fluorescence in situ hybridisation analysis for mTOR and RPS6 loci showed that 11 of 33 and 21 of 44 tumours had loss of one copy of the respective genes, results which correlated with the loss of the relevant total proteins. Fluorescence in situ hybridisation analysis for loci containing TSC1 and TSC2 revealed that all cases analysed harboured two copies of the respective genes. On the basis of p-mTOR and or p-p70S6K expression there is evidence indicating that 65% of the chordomas studied may be responsive to mTOR inhibitors, rapamycin or its analogues, and that patients may benefit from combined therapy including drugs that inhibit AKT.

Sacral chordoma: can local recurrence after sacrectomy be predicted?

UNLABELLED: Surgical resection margins are reportedly the most important predictor of survival and local recurrence with sacral chordomas. We examined the relevance of invasion of the surrounding posterior pelvic musculature (piriformis and gluteus maximus) at initial diagnosis to local recurrence after sacrectomy. We retrospectively reviewed 18 patients with histologically verified sacral chordoma seen at our institution between 1998 and 2005. There were 14 men and four women with a mean age of 65.1 years (range, 31-78 years). The average overall followup was 4.4 years (range, 0.5-10 years), 5.4 years for the living patients (range, 3-10 years), and 2.8 years for the deceased (range, 0.5-5.4 years). Local recurrence occurred in 12 patients (66%) 29 months postoperatively (range, 2-84 months). Six of these patients had wide excisions at initial surgery, five had marginal excisions, and one had an intralesional excision. Ten patients had wide surgical margins, six of whom (60%) had local recurrences. Tumor invasion of adjacent muscles at presentation was present in 14 patients, 12 of whom (85%) had local recurrences. Sacroiliac joint involvement was seen in 10 patients, nine of whom (90%) had local recurrences. The findings suggest obtaining wide surgical margins posteriorly, by excising parts of the piriformis, gluteus maximus, and sacroiliac joints, may result in better local disease control in patients with sacral chordoma. LEVEL OF EVIDENCE: Level IV, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The SMILES prosthesis in salvage revision knee surgery.

Revision total knee arthroplasty using a second generation modular rotating hinge design was done on thirty two knees in 30 patients over an 8-year period. Twenty-nine knees in 29 patients were followed up for 4.5-11 years (mean, 58 months). Four prostheses failed and two patients had died and one patient was lost to followup. Indications for revision were recurrent sepsis (five knees), component failure (four knees), ligamentous instability (two knees), aseptic loosening (10 knees), fracture (six knees), and gross bone loss (five knees). Early results have demonstrated improvement in both the Knee Society knee and function Scores and range of movement. The Knee Society knee score improved from 26 preoperatively to 68 postoperatively. The function score improved from 27 preoperatively to 75 postoperatively. One patient had evidence of aseptic loosening on radiographs, and the patellofemoral complication rate was low at 6%. This short-term clinical and radiographic review has demonstrated encouraging results in the use of a custom-made second generation rotating hinge component when used in revision knee surgery.

Composite ceramic bone graft substitute in the treatment of locally aggressive benign bone tumours.

PURPOSE: To report the use of a composite ceramic bone graft substitute containing calcium sulphate and hydroxyapatite (HA) in the treatment of large expansive osteolytic benign bone tumours. METHODS: 4 women and 9 men aged 8 to 49 (mean, 22) years with aneurysmal bone cysts (n=6) or giant cell tumours (n=7) in the epi- or meta-physeal areas of the lower limbs underwent curettage, phenolisation, and filling with bone graft substitute containing calcium sulphate and HA. The mean tumour size was 38.5 (range, 18-65) ml. The patients were followed up for a mean of 41 (range, 33-52) months. Range of movement, Musculoskeletal Tumor Society Rating Score (MTSRS), and haematological and blood biochemical parameters were measured. RESULTS: Two patients had recurrence at 7 and 9 months, both progressed to grade-III giant cell tumours. One underwent revision with an iliac crest autograft, whereas the other underwent en bloc excision and prosthetic replacement. The 11 other lesions displayed clinical and radiological consolidation at a mean of 4.6 (range, 3-7) months. No restriction of range of movement was observed, except in the patient undergoing prosthetic replacement. The mean MTSRS was 96% (range, 83-100%) of that expected for normal function. During the follow-up period, haematological and blood biochemical parameters stayed within normal limits. CONCLUSION: Composite bioceramic osteoconductive grafts, which combine porous HA with calcium sulphate, provide a framework for human osteogenesis and avoid donor-site morbidity (autologous bone graft harvesting). Tumour recurrence remains a major concern especially in young patients, as revision invariably requires removal of additional bone, potentially compromising joint integrity.

Endoprosthetic replacement of the distal humerus following resection of bone tumours.

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.

Primary tumours of the synovium. A report of four cases of malignant tumour.

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.

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.

Interobserver variation in the measurement of patellar height after total knee arthroplasty.

We assessed the reproducibility and accuracy of four ratios used to measure patellar height, namely the Blackburne-Peel, Caton-Deschamps, Insall-Salvati and modified Insall-Salvati, before and after total knee arthroplasty. The patellar height was measured, by means of the four ratios, on the pre- and post-operative lateral radiographs of 44 patients (45 knees) who had undergone total knee arthroplasty. Two independent observers measured the films sequentially, in identical conditions, totalling 720 measurements per observer. Statistical analysis, comparing both observers and ratios, was carried out using the intraclass correlation coefficient. Before operation there was greater interobserver variation using either the Insall-Salvati or modified Insall-Salvati ratios than when using the Caton-Deschamps or Blackburne-Peel methods. This was because of difficulty in identifying the insertion of the patellar tendon. Before operation, there was a minimal difference in reliability between these methods. After operation the interobserver difference was greatly reduced using both the Caton-Deschamps and Blackburne-Peel methods, which use the prosthetic joint line, compared with the Insall-Salvati and modified Insall-Salvati, which reference from the insertion of the patellar tendon. The theoretical advantage of using the Insall-Salvati and modified Insall-Salvati ratios in measuring true patellar height after total knee arthroplasty needs to be balanced against their significant interobserver variability and inferior reliability when compared with other ratios.

Non-invasive distal femoral expandable endoprosthesis for limb-salvage surgery in paediatric tumours.

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 degrees (100 degrees to 120 degrees ). The mean Musculoskeletal Tumour Society score was 68% (11 to 29). Complications developed in two patients; one developed a flexion deformity of 25 degrees 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.

A knee-sparing distal femoral endoprosthesis using hydroxyapatite-coated extracortical plates. Preliminary results.

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 degrees (20 degrees to 120 degrees) 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.

The novel use of resorbable Vicryl mesh for in vivo tendon reconstruction to a metal prosthesis.

We examined the mechanical properties of Vicryl (polyglactin 910) mesh in vitro and assessed its use in vivo as a novel biomaterial to attach tendon to a hydroxyapatite-coated metal implant, the interface of which was augmented with autogenous bone and marrow graft. This was compared with tendon re-attachment using a compressive clamp device in an identical animal model. Two- and four-ply sleeves of Vicryl mesh tested to failure under tension reached 5.13% and 28.35% of the normal ovine patellar tendon, respectively. Four-ply sleeves supported gait in an ovine model with 67.05% weight-bearing through the operated limb at 12 weeks, without evidence of mechanical failure. Mesh fibres were visible at six weeks but had been completely resorbed by 12 weeks, with no evidence of chronic inflammation. The tendon-implant neoenthesis was predominantly an indirect type, with tendon attached to the bone-hydroxyapatite surface by perforating collagen fibres.

Topographical variation in glycosaminoglycan content in human articular cartilage.

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.

Osteofibrous dysplasia of the tibia. Is there a need for a radical surgical approach?

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.

Stanmore non-invasive growing arthrodesis endoprosthesis in the reconstruction of complicated total knee arthroplasty: A case report.

As the number of primary and revision arthroplasties performed each year increases, the complexity of the reconstructive efforts also increases. A case of a patient with a total knee arthroplasty complicated with infection, deficient extensor mechanism, bone loss and limb shortening of 5.5 cm is reported. We describe an alternative surgical technique of reconstruction of the knee and lengthening of the limb using the Stanmore Non-Invasive Growing-Distal Femoral Prosthesis. The prosthesis had a magnetic disc attached to a gearbox. The generation of an external electromagnetic field caused the magnetic disc to rotate and lengthen the prosthesis. This reconstructive technique has not been described in the literature.

Massive endoprostheses for giant cell tumours of the distal femur: A 12-year follow-up.

We performed a retrospective analysis of twenty-five consecutive massive articulating endoprostheses that were inserted at our unit during the management of patients with Giant Cell Tumours of their distal femur. Fifteen of these implants were fixed hinge devices and ten were rotating hinge devices with HA collars (since 1993). None of these cases were revised for sepsis. There had been no cases of recurrent disease or amputation. The mean follow-up was 12 years (range = 5-18 years). The average age at time of insertion was 37 years. Young patients with fixed hinged devices developed a high incidence (33%) of aseptic loosening. They also had a significant rate of re-bushing. Results of the rotating hinge prosthesis with HA collar were much more promising. Functional scores were good after a period of 12 years despite the young age group.

Neoadjuvant chemotherapy with doxorubicin and cisplatin in malignant fibrous histiocytoma of bone: A European Osteosarcoma Intergroup study.

PURPOSE: Studies involving small case series have suggested that malignant fibrous histiocytoma of bone (MFH-B) is a chemosensitive tumor and that chemotherapy may improve survival. In this study, we evaluated clinical and pathologic response rates and survival in a series of patients treated with a consistent chemotherapy regimen of doxorubicin and cisplatin (DOX/DDP). PATIENTS AND METHODS: Study patients were required to have biopsy-proven MFH-B, no previous chemotherapy, and primary or metastatic measurable disease and to be /= 90% necrosis). Median time to progression was 56 months, and the 5-year progression-free survival rate was 56% (95% confidence interval [CI], 40% to 72%). Median survival time was 63 months, and the 5-year survival rate was 59% (95% CI, 41% to 77%). Patients with a good pathologic response had longer survival times and times to progression than did those with a poor response. Also treated were two patients with locally recurrent and nine with metastatic disease, and these patients had a median survival time of 17.5 months. CONCLUSION: Our study suggests that adjuvant or neoadjuvant chemotherapy with DOX/DDP is beneficial in MFH-B. Good pathologic response rates and survivals are quite comparable with those for osteosarcoma, a related bone tumor for which adjuvant or neoadjuvant chemotherapy is an accepted practice.

A customised replacement for polyostotic fibrous dysplasia of the upper femur. A 51-year follow-up.

We report the case of a 12-year-old boy with polyostotic fibrous dysplasia of the upper femur in whom a massive customised polyethylene prosthesis functioned successfully for more than fifty years.

Extensor mechanism reconstruction after proximal tibial replacement.

We developed an in vivo model of the attachment of a patellar tendon to a metal implant to simulate the reconstruction of an extensor mechanism after replacement of the proximal tibia. In 24 ewes, the patellar tendon was attached to a hydroxyapatite (HA)-coated titanium prosthesis. In 12, the interface was augmented with autograft containing cancellous bone and marrow. In the remaining ewes, the interface was not grafted. Kinematic gait analysis showed nearly normal function of the joint by 12 weeks. Force-plate assessment showed a significant increase in functional weight-bearing in the grafted animals (p = 0.043). The tendon-implant interface showed that without graft, encapsulation of fibrous tissue occurred. With autograft, a developing tendon-bone-HA-implant interface was observed at six weeks and by 12 weeks a layered tendon-fibrocartilage-bone interface was seen which was similar to a direct-type enthesis. With stable mechanical fixation, an appropriate bioactive surface and biological augmentation the development of a functional tendon-implant interface can be achieved.

Metal ion levels after metal-on-metal proximal femoral replacements: a 30-year follow-up.

Metal-on-metal hip bearings are being implanted into younger patients. The consequence of elevated levels of potentially carcinogenic metal ions is therefore a cause for concern. We have determined the levels of cobalt (Co), chromium (Cr), titanium (Ti) and vanadium (Va) in the urine and whole blood of patients who had had metal-on-metal and metal-on-polyethylene articulations in situ for more than 30 years. We compared these with each other and with the levels for a control group of subjects. We found significantly elevated levels of whole blood Ti, Va and urinary Cr in all arthroplasty groups. The whole blood and urine levels of Co were grossly elevated, by a factor of 50 and 300 times respectively in patients with loose metal-on-metal articulations when compared with the control group. Stable metal-on-metal articulations showed much lower levels. Elevated levels of whole blood or urinary Co may be useful in identifying metal-on-metal articulations which are loose.