Thumb metacarpophalangeal ulnar collateral ligament injuries: a biomechanical simulation study of four static reconstructions.

摘要

PURPOSE: To determine the optimal tunnel placement positions for tendon graft reconstruction of chronic thumb metacarpophalangeal (MCP) ulnar collateral ligament injuries that would stabilize the joint while maintaining motion. METHODS: Four commonly used tunnel placement methods were simulated on a cadaveric model using fresh-frozen thumbs and a suture/screw construct. The methods were as follows: (1) triangular configuration with apex proximal, (2) triangular configuration with apex distal, (3) cruciate configuration, and (4) parallel configuration. Stability was tested by valgus loading at 0 degrees and 30 degrees , and range of motion was tested by loading the thumb tendons. Statistical analysis was performed by 1-way analysis of variance testing. RESULTS: Valgus load stability testing at 0 degrees and 30 degrees showed that all 4 reconstruction methods stabilized the MCP joint compared with the fully sectioned state. The amount of stability achieved was not significantly different between the 4 methods. Only the reconstruction method, however, with a triangular configuration with the apex proximal restored flexion/extension range of motion not significantly different from the intact state. The other 3 methods resulted in significantly decreased range of motion. CONCLUSIONS: The reconstruction tunnel positioning of triangular configuration with apex proximal stabilizes the thumb MCP joint while maintaining flexion/extension range of motion. We recommend this configuration for chronic MCP joint injuries in which the native ulnar collateral ligament is inadequate and tendon graft reconstruction is performed.