Late complications and survival of endoprosthetic reconstruction after resection of bone tumors.

BACKGROUND While complications following massive endoprosthetic reconstruction have been previously described, the incidence and effects of these complications over extended periods of time have not been well characterized in large series. QUESTIONS/PURPOSES We therefore determined: (1) incidence and types of complications; (2) relative risk of complications; (3) likelihood of secondary complications; (4) whether modularity altered such complications; (5) implant failure and limb salvage rates and (6) implant survival over extended followup. METHODS We retrospectively reviewed 232 patients (241 implants: 50 custom,191 modular) who underwent endoprosthetic reconstruction for malignant and aggressive bone tumors between 1980 and 2002. Complications were classified as infection, mechanical, superficial soft tissue, deep soft tissue, or dislocation. Survival was determined by Kaplan-Meier analysis. Minimum followup was 5 years (mean: 10 years; range: 5-27 years). RESULTS One hundred thirty-seven of 232 patients (59%) underwent a single reconstruction. Ninety-five patients had 242 additional procedures. Forty-four revised patients retained their original prosthesis. Limb salvage rate was 90%; implant failure (removal of the cemented part) was seen in 29% (70/241) with a median survival of 190 months. Twenty-five of 50 custom implants failed (8 then failed again) while 30/180 modular implants failed (7 then failed again). Of 70 instances of implant failure, 38/70 were mechanical, 27/70 infectious. Risk of infection increased 30% after a second procedure; 16 of 24 amputations were performed because of infection. CONCLUSIONS Mechanical complications were the most common cause of implant failure. Infection was the leading cause of both complication and amputation; risk of infection increased substantially with revision surgery. Modular implants had fewer mechanical complications, thus leading to fewer revisions and subsequent infections.