Abstract
Objective To evaluate the survival time, the failure rate and its causes, and the functional
results of cemented endoprostheses, with a polyethylene body, used after resection
of primary bone tumors of the distal femur.
Methods A retrospective study including 93 primary and 77 review procedures performed between
1987 and 2014. Survival was obtained by the Kaplan Meyer analysis, and the risk factors
for implant failure were assessed through the Cox proportional risk model. The causes
of endoprosthesis failure were classified according to Henderson et al. into five
types: soft-tissue failure, aseptic loosening, structural fracture, infection, and
tumor recurrence. The functional evaluation was performed using the functional classification
system of the Musculoskeletal Tumor Society (MSTS) of bone sarcomas of the lower extremity,
Brazilian version (MSTS-BR).
Results Osteosarcoma was the most common diagnosis; 64.5% of the patients were younger than
20 years of age; the mean follow-up was of 124.3 months. The failure rate of the primary
implant was of 54.8%, and the mean survival was of 123 months. The estimated survival
of the primary implant was of 63.6%, 43.5%, 24.1%, and 14.5% in 5, 10, 15, and 20
years respectively. The most common cause of failure was type 2 (37.3%). Age ≤ 26
years and right side were risk factors for failure. The mean MSTS-BR score was of
20.7 (range: 14 to 27).
Conclusion The results obtained for the failure rate and survival of the implant are in accordance
with those of the literature, so the procedure herein studied is adequate and yields
satisfactory functional results, even in the long term.
Keywords
endoprostheses - femur - bone neoplasms - osteosarcoma - reconstructive surgical procedures
- limb salvage
