UNCEMENTED MASSIVE ENDOPROSTHESES FOR PRIMARY BONE TUMOURS : A 7 YEAR FOLLOW UP.

Abstract

Retrospective analysis of all uncemented massive endoprostheses inserted at our unit in the management of primary bone tumours with a minimum follow up of 5 years.

Methods. The case notes and radiographs of all patients were reviewed. The group consisted of a total of 52 patients of which 4 (8%) were lost to follow up. Kaplan-Meier Cumulative Survival Graphs were created for mortality, amputation, revision and infection for the whole group and for each individual prosthesis.

Results. The mean follow up was seven years (63–107 months). The average age at time of insertion was 19 years; twenty-six patients were skeletally immature. The majority of implants were distal femoral (31) and proximal tibial (14). Osteosarcoma was the commonest diagnosis.

The rate of infection was 12.5%, aseptic loosening 6%, amputation due to local recurrence 10% and the mortality 21%.

All the deaths occurred within 3 years of the implant being inserted and were all due to systemic progression of the disease. The amputations for local recurrence occurred throughout the follow up period, the latest being at 71 months. Revisions for infections and aseptic loosening all occurred early (within 3 years). All cases of aseptic loosening occurred in distal femoral replacements (10%) and were related to divergent canals. Proximal tibial replacements had the highest rate of infection (23%). Rates of infection were not higher in the minimally invasive grower (12.5 %) when compared to the group as a whole.

Conclusion. We have shown a reduced rate of aseptic loosening (6%), particularly in the skeletally immature, when compared to our units results for cemented fixed hinged prostheses. The uncemented prosthesis is a successful implant that needs careful consideration, especially in the skeletally immature. Careful preoperative planning and surgical technique are of the utmost importance.