An innovative approach to concave-convex allograft junctions: a biomechanical study.

Allograft bone is often used in oncologic and trauma limb salvage procedures. In this study, we hypothesize that a concave-convex allograft junction with plate fixation would improve multiple aspects of the reconstruction process, allowing for a larger contact surface area between the allograft junction and increased uniformity in pressure distribution at the junction. Thirty large femoral artificial polyresin femurs were randomly separated into 2 groups: allograft junctions fixed with flat locking plates and allograft junctions fixed with prebent locking plates. Each group was then randomly subdivided into 3 sets: concave-convex allograft junctions, matched transverse-cut allograft junction, and non-matched transverse-cut allograft junctions. All but 1 reconstructions of concave-convex allograft junctions, compared with non-matched or matched transverse-cut allograft junctions fixed with flat or pre-bent locking plates showed statistically significantly greater mean contact surface area and greater mean percent contact surface area (P<.05). Concave-convex allograft junctions demonstrated increased mean contact surface area, mean percent contact surface area, and a more uniform pressure distribution. We believe our approach to allograft junctions using concave-convex reamers may improve multiple aspects of the reconstruction process, allowing for increased contact surface area between the allograft junction, increased uniformity in pressure distributions at the allograft junction, and decreased length of time taken for intraoperative preparation.