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.

Cite this article: Bone Joint J 2014;96-B:263–9.

We report a case which highlights the progression of osteofibrous dysplasia to adamantinoma and questions whether intralesional curettage is the appropriate treatment. The role of a joint-sparing massive endoprosthesis using cortical fixation is demonstrated and we describe a unique biomedical design which resulted in the manufacture of an end cap to allow amputation through a custom-made proximal tibial replacement, rather than an above-knee amputation following recurrence

Between 1997 and 2007, 68 consecutive patients underwent replacement of the proximal humerus for tumour using a fixed-fulcrum massive endoprosthesis. Their mean age was 46 years (7 to 87). Ten patients were lost to follow-up and 16 patients died. The 42 surviving patients were assessed using the Musculoskeletal Tumor Society (MSTS) Score and the Toronto Extremity Salvage Score (TESS) at a mean follow-up of five years and 11 months (one year to ten years and nine months). The mean MSTS score was 72.3% (53.3% to 100%) and the mean TESS was 77.2% (58.6% to 100%). Four of 42 patients received a new constrained humeral liner to reduce the risk of dislocation. This subgroup had a mean MSTS score of 77.7% and a mean TESS of 80.0%. The dislocation rate for the original prosthesis was 25.9; none of the patients with the new liner had a dislocation at a mean of 14.5 months (12 to 18). Endoprosthetic replacement for tumours of the proximal humerus using this prosthesis is a reliable operation yielding good results without the documented problems of unconstrained prostheses. The performance of this prosthesis is expected to improve further with a new constrained humeral liner, which reduces the risk of dislocation

Failure of massive knee endoprostheses implanted for malignant tumours of the distal femur in children presents a difficult problem. We present the results of rotationplasty undertaken under these circumstances in four boys. They had been treated initially at a mean age of 9.5 years for a stage-IIB malignant tumour of the distal femur by resection and implantation of a massive knee endoprosthesis. After a mean period of eight years and a mean of four operative procedures, there was failure of the endoprosthesis because of aseptic loosening in two and infection in two. Function was poor with a mean Musculoskeletal Tumor Society score of 7.5/30, and considerable associated psychological problems. At a mean follow-up of 4.5 years after rotationplasty there was excellent function with a mean score of 27.5/30 and resolution of the psychological problems