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: 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: 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: 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.