title: Thumb metacarpophalangeal ulnar collateral ligament injuries: a biomechanical simulation study of four static reconstructions.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Joint Diseases/New York University School of Medicine, New York, NY 10029, USA. steve.lee@msnyuhealth.org
authors.forename: Steve K
authors.initials: SK
authors.lastname: Lee
authors.forename: Erik N
authors.initials: EN
authors.lastname: Kubiak
authors.forename: Ericka
authors.initials: E
authors.lastname: Lawler
authors.forename: Kazuho
authors.initials: K
authors.lastname: Iesaka
authors.forename: Frank A
authors.initials: FA
authors.lastname: Liporace
authors.forename: Steven M
authors.initials: SM
authors.lastname: Green
mesh_terms: D001696:Biomechanical Phenomena; D017885:Collateral Ligaments / Q000293:injuries / Q000601:surgery*; D006225:Hand / Q000601:surgery; D006230:Hand Injuries / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D008662:Metacarpophalangeal Joint / Q000293:injuries / Q000601:surgery; D019637:Orthopedic Procedures / Q000379:methods*; D013710:Tendons / Q000637:transplantation; D013933:Thumb / Q000293:injuries / Q000601:surgery*; D014184:Transplantation, Homologous; D014457:Ulna