UNCEMENTED MASSIVE ENDOPROSTHESES FOR PRIMARY BONE TUMORS: A SEVEN-YEAR FOLLOW-UP

Abstract

Introduction and Aims: Retrospective analysis of all uncemented massive endoprostheses inserted at our unit in the management of primary bone tumors with a minimum follow-up of five years.

Method: The case notes and radiographs of all patients were reviewed. The group consisted of a total of 52 patients, of which four (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; 26 patients were skeletally immature. The majority of implants were distal femoral (31) and proximal tibial (14). Osteosarcoma was the most common 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 three 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 three 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 unit’s results for cemented fixed hinged prostheses. The uncemented prosthesis is a successful implant that needs careful consideration, especially in the skeletally immature. Careful pre-operative planning and surgical technique are of the utmost importance.