title: Biomechanic analysis of trapeziectomy, ligament reconstruction with tendon interposition, and tie-in trapezium implant arthroplasty for thumb carpometacarpal arthritis: a cadaver study.
abstract: OBJECTIVE
  Thumb carpometacarpal joint arthritis has been commonly treated with some combination of resection of the trapezium and interposition of a spacer using either a biologic or artificial material plus tenodesis to reconstruct the volar oblique ligament. The purpose of this study was to evaluate the biomechanic stability of the classic ligament reconstruction with tendon interposition (LRTI) or without tendon interposition compared with a newly developed 1-piece silicone trapezium implant.
  
  
  METHODS
  Twelve cadaver arm specimens had the following procedures: resection of the trapezium, tendon interposition, ligament reconstruction, LRTI, and the silicone implant. Biomechanic testing of joint stability was performed with a physiologic loading protocol before and after each procedure.
  
  
  RESULTS
  The implant significantly corrected the axial displacement after trapeziectomy and resulted in less radial displacement than LRTI. It significantly reduced angulation of the thumb metacarpal base but resulted in more rotation of the thumb during simulated pinch. There was no significant difference in stability measures between trapeziectomy and LRTI or ligament reconstruction without tendon interposition.
  
  
  CONCLUSIONS
  We found several biomechanic advantages to the implant compared with LRTI. Advantages include reduction in axial and radial displacement and maintenance of the trapezial space. We attribute these advantages to the effect of the implant as a spacer. The significant rotation with the implant, however, raises questions concerning implant design and fixation. We found no biomechanic advantage to LRTI or ligament reconstruction without tendon interposition over trapeziectomy alone.
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington School of Medicine, Seattle, WA 98195-6500, USA. lurias@u.washington.edu
authors.forename: Shai
authors.initials: S
authors.lastname: Luria
authors.forename: Thanapong
authors.initials: T
authors.lastname: Waitayawinyu
authors.forename: Nicholas
authors.initials: N
authors.lastname: Nemechek
authors.forename: Philippe
authors.initials: P
authors.lastname: Huber
authors.forename: Allan F
authors.initials: AF
authors.lastname: Tencer
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Trumble
mesh_terms: D019643:Arthroplasty, Replacement; D001696:Biomechanical Phenomena; D002102:Cadaver; D052737:Carpometacarpal Joints / Q000601:surgery*; D006801:Humans; D008023:Ligaments, Articular / Q000601:surgery; D010003:Osteoarthritis / Q000601:surgery*; D019736:Prostheses and Implants; D012399:Rotation; D012828:Silicones; D013710:Tendons / Q000601:surgery; D013933:Thumb / Q000601:surgery*; D051222:Trapezium Bone / Q000601:surgery
chemical_list: D012828:Silicones