Survival of current production tumor endoprostheses: complications, functional results, and a comparative statistical analysis.

BACKGROUND AND OBJECTIVES: Retrospectively analyze outcomes of current-generation Global Modular Replacement System (GMRS) modular tumor endoprosthesis for the lower limb in primary and secondary implantation procedures.

METHODS: Two hundred ninety five prostheses were implanted, 197 were primary implants, 98 were for revision surgery; revision procedures included 84 failed tumor reconstructions and 14 failed non-tumor reconstructions. Anatomic sites included: distal femur 199; proximal tibia 60; proximal femur 32;total femur 4. Endoprosthesis failures were classified as soft-tissue failures (Type 1), aseptic loosening (Type 2), structural fracture (Type 3), infection (Type 4), and tumor recurrence (Type 5). MSTS functional scores were measured.

RESULTS: The overall failure rate was 28.8% and failure occurred at a median of 1.7 years (range, 1 month to 7 years). At a mean oncologic follow up of 4.2 years (range, 2-8 years), 195 patients are continuously NED, 43 NED after treatment of relapse, 10 AWD, 33 DWD. There was a significant difference in implant survival of all modes of failure between primary and revision implants (P = 0.03). No prosthetic fracture occurred. The average functional score was 81.6% (24.5).

CONCLUSIONS: Mid-term results with GMRS are promising, with good functional results and low incidence of complications for primary implants.

LEVEL OF EVIDENCE: Therapeutic study, level IV-1 (case series).