Following wide excision of a proximal tibial osteosarcoma, reconstruction is done with a massive osteoarticular allograft rather than a metallic megaprosthesis. Which complication is characteristically associated with allograft reconstruction and not seen with an endoprosthesis?

• A Allograft fracture and nonunion at the host-donor junction ✓
• B Deep periprosthetic infection
• C Aseptic loosening of the implant-bone interface
• D Periprosthetic joint dislocation

Explanation

Massive allografts heal slowly and depend on creeping substitution, so fracture of the graft and nonunion at the osteosynthesis site are complications essentially exclusive to biological reconstructions, occurring in up to a fifth of cases. Infection, instability and failure occur with both methods, though infection tends to be more devastating with allografts. Loosening is a prosthetic failure mode. Allograft advantage is better soft tissue attachment and potential longevity in young patients.

Reference: Campbell's Operative Orthopaedics, 14th ed.

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