Background: Outcomes of interposition arthroplasty for treatment of elbow arthritis are highly dependent on elbow stability. The purpose of this study was to determine whether interposition arthroplasty with a novel bidirectional ligament reconstruction technique could adequately restore the static stability of the native elbow. Methods: Static varus and valgus elbow stability was tested in 7 cadaver elbows with intact ligaments and capsule at 5 flexion angles (0°, 30°, 60°, 90°, and 120°). At each angle, the distance between fixed reference points across the elbow was measured both medially and laterally. The elbows were then destabilized and an interposition arthroplasty with ligament reconstruction was performed. Static elbow stability was reassessed by comparing postoperative deflection measurements with those of the native state. Graft slippage or loosening was visually assessed following testing. Results: Interposition arthroplasty was performed in 7 cadaver specimens. Following ligament reconstruction, specimens reproduced the flexion angle-dependent static stability of native elbows to both varus and valgus stress. The greatest deflection changes between native elbows and elbows after interposition arthroplasty were 2.7% ( P = .13) medially and 2.3% ( P = .42) laterally, which were not significant. There was no loosening or slippage of either the interposition graft or the ligament reconstruction grafts. Conclusions: Cadaveric elbow specimens underwent interposition arthroplasty with a novel technique for bidirectional ligament reconstruction. Static stability was maintained at varying degrees of elbow flexion, comparable to that of the native elbow. Interposition and ligament reconstruction grafts maintained secure fixation following static biomechanical testing.
