Single-Bundle vs Double-Bundle (Anatomical) Reconstruction of the Thumb Ulnar Collateral Ligament: Biomechanical Study

BackhroundsThe goal of this study is to compare the biomechanical properties of anatomic (doublebundle)versus single-bundle reconstruction of the thumb metacarpophalangeal (MCP)joint ulnar collateral ligament (UCL) in a cadaveric modelMethodsTwelve fresh frozen cadaver hands were randomly assigned to single- or double-bundlereconstruction groups using a palmaris longus autograft and tenodesis screws. Two blindedexaminers performed mechanical testing and measurements using fluoroscopic imaging.We evaluated MCP joint congruence and angle in the coronal plane at °30 ,°0, and °60 offlexion with valgus loads of 1.36 and 2.72 kg. Maximum MCP flexion and extension with a0.45 kg load was also measured.ResultsThere was no significant difference between single- versus double-bundle reconstruction inulnar congruence or MCP angle. With varying amounts of flexion, there was no significantdifference in MCP valgus angle between the 2 techniques, suggesting comparable jointcongruity and coronal MCP angle along the arc of thumb MCP motionConclusionsSingle- and double-bundle UCL reconstructions of the thumb MCP joint have comparablebiomechanical properties in regard to joint congruity under valgus load.