We reviewed 29 patients who had undergone intercalary resection for malignant tumours. Of these, 14 had received segmental allograft reconstruction and 15 extracorporeally-irradiated autograft. At a mean follow-up of 71 months (24 to 132), 20 were free from disease, five had died and four were alive with pulmonary metastases. Two patients, one with an allograft and one with an irradiated autograft, had a local recurrence. Reconstruction with extracorporeally-irradiated autograft has a significantly lower rate of nonunion (7% Extracorporeally-irradiated autograft could be an acceptable alternative for reconstruction after intercalary resection, especially in countries where it is difficult to obtain allografts.
The size selection of the outer metal shell to fit the acetabulum is a dilemma to the surgeons for the bipolar hemiarthroplasty. However, no body ever mentioned the final results of motion behaviour of bipolar hip endoprostheses by different size selections of outer metal shell. The purpose of this study was to evaluate the motion behaviour of bipolar hip endoprostheses under different sizes of outer metal shell. A fresh cadaver of size of 50 mm and three different sizes of bipolar hip endoprostheses were used to evaluate the motion behaviour of bipolar hip endoprostheses under the MTS machine. Each size had six sets of bipolar hip endoprostheses to get statistical data. The single axial load scaled from 300 N to 3000 N with increment of 300 N was applied on both the inner bearing and outer bearing to obtain the frictional torque of two bearings randomly. The axis was rotated from 0° to 90° under the speed of 1 deg/sec. The motion behaviour of bipolar hip endoprostheses was predicted and verified by the comparison of the frictional torque of both bearings and repeat the experiments again. The dynamic frictional torque of 48mm was larger than the dynamic frictional torque of the 50mm at the inner bearing. The size of 52mm had the largest value of dynamic frictional torque for the outer bearing under any load condition. The prosthesis that had larger outer metal shell than the acetabulum had the same relative motion behaviour as the design hypotheses, because the difference of frictional torque was much higher. In conclusion, the motion of the bipolar hip endoprostheses is influenced by the frictional behaviour of the both bearings. The relative motion of bipolar hip endoprostheses with a larger outer shell size will have an idea relative motion behaviour, because the larger difference of frictional torque. The thickness of the UHMWPE has a positive effect to reduce the friction between the UHMWPE liner and metal head.
Autogenous bone graft which has been either autoclaved or irradiated is commonly used in oriental countries as an alternative to allograft. We started to use the technique of extracorporeal irradiation of the resected specimen and reimplantation (ECIR) in 1991. There was, however, a high incidence of fracture of the irradiated bone and loss of articular cartilage. In an attempt to reduce these complications, we combined the irradiated autograft with a conventional arthroplasty. Between 1995 and 1998, 14 patients underwent limb salvage by this method. Seven had an osteosarcoma, two bony metastases, three a chondrosarcoma, one a malignant fibrous histiocytoma, and one a leiomyosarcoma. Ten tumours were located in the proximal femur, two in the proximal humerus, and two in the distal femur. One patient who had a solitary metastasis in the proximal part of the left femur died from lung metastases 13 months after operation. The remaining 13 patients were alive and without evidence of local recurrence or distant metastases at a mean follow-up of 43 months (28 to 72). Postoperative palsy of the sciatic nerve occurred in one patient, but no complications such as wound infection, fracture, or nonunion were seen. All host-irradiated bone junctions healed uneventfully within eight months. Using the Enneking functional evaluation system, the mean postoperative score for all 14 patients was 80% (57 to 93). The use of irradiated autograft prosthesis composites reduces the complications of ECIR and gives good functional results. It may be a good alternative in limb-salvage surgery, especially in countries where it is difficult to obtain allografts.
