In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery.

The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 μg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 μg/l (0.25 to 2.3) and the cobalt level was 0.4 μg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 μg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 μg/l (0.25 to 3.9) whereas the cobalt level was 1.4 μg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001).

Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

We studied the bone mineral density (BMD) of 48 long-term survivors of highly malignant osteosarcoma who had been treated according to the chemotherapy protocols of the German- Swiss-Austrian Co-operative Osteosarcoma Study Group which include high-dose methotrexate. The mean age of the patients was 31 ± 4.2 years and the mean follow-up 16 ± 2.2 years. The BMD of the lumbar spine and of the proximal femur of the non-operated side was measured by dual- energy x-ray absorptiometry. A questionnaire was given to determine life-style factors, medical history and medication. Ten patients were osteoporotic, 21 osteopenic and 17 normal according to the WHO definition.

Eighteen patients suffered fractures after receiving chemotherapy and all had significantly lower levels of BMD for all the sites measured.

Primary malignant tumours should be resected with wide margins. This may be difficult to apply to lesions of the spine. We undertook total vertebrectomy on seven patients, four males and three females with a mean age at operation of 26.5 years (6.3 to 45.8). The mean follow-up was 52.3 months. Histological examination revealed a Ewing’s sarcoma in two patients and osteosarcoma, leiomyosarcoma, spindle-cell sarcoma, chondrosarcoma and malignant schwannoma in one each. In five patients, histological examination showed that a wide resection had been achieved. At follow-up there was no infection and a permanent neurological deficit was only seen in those patients in whom the surgical procedure had required resection of nerve roots. Despite the high demands placed on the surgeon and anaesthetist and the length of postoperative care we consider total vertebrectomy to be an appropriate procedure for the operative treatment of primary malignant lesions of the spine.

In 251 patients over a period of 15 years an uncemented Kotz modular femoral and tibial reconstruction mega prosthesis was implanted after resection of a malignant tumour of the lower limb. Twenty-one patients (8.4%) underwent revision for aseptic loosening, again using an uncemented prosthesis, and five of these required a further revision procedure. The median follow-up time from the first revision was 60 months (11 to 168) and after a second revision, 33 months (2 to 50). The probability of a patient avoiding aseptic loosening for ten years was 96% for a proximal femoral, 76% for a distal femoral and 85% for a proximal tibial implant.

At the time of follow-up all radiographs were assessed according to the International Symposium of Limb Salvage criteria. The first radiological signs of aseptic loosening were always seen at the most proximal or distal part of the anchorage stem at a mean of 12 months (4 to 23) after the first implantation. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed a mean of 88% of normal function.

We treated 106 patients with a peripheral osteoid osteoma by conventional surgical methods; 81 had curettage and 25 en-bloc resection.

The rate of local recurrence after curettage was 12% and after en-bloc resection 4.5%. Postoperative fractures were observed in 3% after curettage and in 4.5% after en-bloc resection.

We compared our findings with those reported in the literature after minimally invasive treatment and concluded that curettage can be regarded as the treatment of choice in patients in whom minimally invasive methods do not offer any advantage, for example, for subperiosteal tumours which are readily accessible, or when the diagnosis is unclear and further histological analysis is required.

We determined serum cobalt levels in 55 patients by atomic absorption spectrophotometry before and after implantation of uncemented total hip arthroplasties. In a randomised, prospective trial 27 wrought Co-28Cr-6Mo-0.2C metal-on-metal articulations were compared with 28 ceramic-on-polyethylene hips which did not contain cobalt. Other sources of iatrogenic cobalt loading were excluded.

The metal-on-metal group produced detectable serum cobalt levels (median 1.1 μg/l after one year) which were significantly different (p < 0.0001) from those of the ceramic-on-polyethylene control group (median below detection limit of 0.3 μg/l after one year). Our findings indicate that metal-on-metal bearings generate some systemic release of cobalt.

We have reviewed the results of one-stage revision surgery in 18 patients for infection of megaprostheses implanted after the resection of malignant bone and soft-tissue tumours.

At a mean follow-up of 52.0 ± 35.0 months (18 to 135) infection was eliminated in 14 of the 18 patients. The infection-free patients showed no abnormal tests for inflammation and had a mean Enneking score of 20.6 ± 5.0 points (maximum 30 points).

We suggest that one-stage revision without exchange of the anchorage parts is justified in patients with megaprostheses infected by antibiotic-sensitive micro-organisms.

From 1986 to 1991 we fitted 20 children with endoprostheses after resection of malignant bone tumours of the leg; six have reached skeletal maturity and are the subject of this study. Reconstruction of defects in growing limbs in which the eventual shortening can be predicted requires the use of extendable prostheses. The mean age at operation was 11 years (9.2 to 13.7) and the average follow-up period was 6.3 years (4.3 to 7.6). The diagnosis was osteosarcoma in five patients and Ewing's sarcoma in one. All tumours were Enneking stage-IIB. When seen for follow-up all patients were free from disease. The extendable implants used included the Pafford-Lewis prosthesis and the Kotz Modular Femur Tibia Reconstruction system with a compatible, newly-designed growth module. Telescope-like elongation of the prostheses was performed by insertion of a screwdriver through a small skin incision. Active epiphyseal growth in the adjacent growth plate was preserved by using prosthetic stems with a smooth surface. The mean length gained was 13.15 cm (4.5 to 19.5) requiring 53 planned procedures. Seven revision operations were necessary for complications. Functional evaluation showed excellent and good results in all cases. Stress-shielding at the site of anchorage of the prosthesis was more pronounced than in adults. Implantation of extendable endoprostheses in children provides a reasonable alternative to rotationplasty, but limb salvage requires more operations.

We describe a method of partial limb salvage for the treatment of large primary malignant tumours of the arm. The tumour-bearing area is resected as a cylindrical segment and the distal arm is then replanted with the necessary shortening. The method is suitable for stage-IIB tumours with or without neurovascular involvement which, because of their extent, could otherwise be adequately treated only by amputation. From 1987 to 1992 we used this method in 12 patients with primary malignant bone or soft-tissue sarcomas. Wide resection margins were achieved in all, but six patients died from their disease at a mean of 21.5 months (6 to 48), none with any local recurrence. Five patients have no evidence of disease at a mean follow-up period of 52.2 months (22 to 78), and one was lost to follow-up at 48 months postoperatively when there was no evidence of disease. The results of the functional evaluation of ten patients with a follow-up of over ten months were excellent in one, good in six and fair in three, by the criteria of Enneking (1987). Recovery after nerve reconstruction was satisfactory in all cases with sensation S3 or higher and motor function M2+ or higher. Detailed evaluation of hand function on the Millesi score rated only 22% (9.6% to 33.7%) as compared with the contralateral side, but the patients were satisfied and refused further operations for the improvement of function. These oncological and functional results allow us to recommend resection-replantation as a valuable alternative to amputation for the treatment of primary malignant tumours of the arm.

We reviewed 236 of the 388 Chiari pelvic osteotomies performed between 1953 and 1967 at the Orthopaedic University Clinic of Vienna for the treatment of congenital dislocation and subluxation of the hip. Over 90% of the operations were performed by Chiari himself. Twenty-one hips had needed reoperation after an average of 15.4 years; the other 215 hips had been followed up for 20 to 34 years (mean 24.8). The overall clinical results were excellent or good in 51.4%, fair in 29.8% and poor in 18.3%. The results were worse with increasing age at operation. The Trendelenburg sign improved only in patients aged seven or less at operation, and range of movement decreased in all cases. Subjectively poor results were seen in patients with pre-operative signs of osteoarthritis. Radiological loss of correction during follow-up was seen only in cases with incomplete primary correction. The addition of an intertrochanteric varus osteotomy in 36 cases did not achieve either better centering or better development of the acetabular roof. Degenerative changes increased significantly during the long-term follow-up, but their progress seemed to have been slowed down by the osteotomy in the younger age groups. Indications and contra-indications for the operation are discussed.