Biomechanical Performance of a New Device for Medial Malleolar Fractures

Background:Displaced medial malleolus fractures require surgical repair because of the critical role the structure plays in normal joint function. Various approaches exist, but options are limited for small fragment fractures. This study compared repair with the Medial Malleolar Sled fixation system (Trimed, Inc, Valencia, CA) to lag screws in 2 modes of biomechanical loading in a cadaveric model.Methods:A Muller type B medial malleolus fracture was simulated on matched pairs of cadaveric lower extremities and repaired with the sled or 2 cancellous lag screws. Tibial distraction (tension, n = 10) or internal rotation (torsion, n = 11) was applied. Fragment movement was measured in the sagittal (tension and torsion) and transverse (torsion-only) planes. Fragment movement at 1 mm and 2 mm (clinical malunion) of gapping during tension and at 2, 4, 6, and 8 N-m during torsion was analyzed via paired t tests.Results:In tension, the load at the 2-mm gap was statistically lower for screws (P = .026). Opening ang...