Background: Roughly 25-35% of patients who are treated with osteoarticular allograft for primary bone sarcomas or aggressive benign bone tumors require surgery in the long-term due to degenerative changes of the articular surface of the allograft. There are three established methods of reconstruction for this complication; a total hip arthroplasty (THA) or total knee arthroplasty (TKA) in the retained osteoarticular allograft, a proximal or distal endoprosthesis after removal of the allograft, and an allograft-prosthesis composite (APC). The aims of this study are 1) to determine the rate of complication and failure of THA/TKA in healed femoral allograft; 2) to compare the methods of revision for allograft degeneration; and 3) to compare the use of arthroplasty in healed allograft to that of arthroplasty in native bone.
Methods: We included all patients with primary bone sarcomas and locally aggressive primary benign bone tumors treated between 1984 and 2014 with an osteoarticular allograft followed by any subsequent arthroplasty technique as described above. Complications and reasons for failure are described following the classification of Henderson et al. Failure was defined as any complication leading to removal of the initial treatment construct. Failure rates of these groups were compared to primary arthroplasty in a live host bone (Control Group).
Results: Complications happened in 25 (61.0%) of the patients with a THA/TKA in the retained allograft, of these, 24 (58.5%) experienced failure, the most common being structural failure/type III (14, 58.3%). Thirteen patients (81.3%) with an endoprosthesis after removal of the allograft experienced complications, all of whom failed. The most common failure modes were aseptic loosening/type II (4, 30.8%) and infection/type IV (5, 38.5%). Complications in patients with an APC were experienced by 12 (85.7%) patients, 11 (78.6%) of whom failed. The most common failure mode was infection/type IV (4, 36.4%). Significantly (p < 0.001) fewer failures were observed in the control group compared to patients with an arthroplasty in a healed allograft.
Conclusions: We found no significant difference in the outcome of treating patients with allograft and subsequent degenerative bone disease with a THA/TKA in a retained allograft, an endoprosthesis after removal of the allograft, or a primary APC, although infection is a significantly greater cause of failure in the latter two. Primary arthroplasty in healed allografts is a less extensive surgery than removing the allograft and shows comparable complication and failure rates.
Level of evidence: Level III, Therapeutic Study.
Keywords: Allograft-prosthesis composite; Complications; Endoprosthesis; Orthopedic oncology; Revision.
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