title: Strain-gauge evaluation of lunate unloading procedures.
abstract: A biomechanical study was undertaken to determine which procedure(s) most effectively relieve load from the lunate. Strain gauges were mounted on the lunates of 20 preserved cadaveric limbs. Three types of procedures were performed: scaphotrapeziotrapezoid arthrodesis, capitohamate arthrodesis, and ulnar lengthening. Load testing was performed both before and after the simulated fusions and ulnar lengthenings. Ulnar lengthening of 3 mm was the most effective method of lunate strain reduction. Capitohamate arthrodesis decreased compressive strain but increased shear strain. Scaphotrapeziotrapezoid fusion significantly increased both compressive and shear strain in the lunate. Of the three procedures that were tested, ulnar lengthening to create a neutral variance is the most reliable means of unloading the lunate.
authors.affiliation: Division of Orthopaedic Surgery, University of Alabama, Birmingham.
authors.forename: V R
authors.initials: VR
authors.lastname: Masear
authors.forename: E G
authors.initials: EG
authors.lastname: Zook
authors.forename: D R
authors.initials: DR
authors.lastname: Pichora
authors.forename: M
authors.initials: M
authors.lastname: Krishnamurthy
authors.forename: R C
authors.initials: RC
authors.lastname: Russell
authors.forename: J
authors.initials: J
authors.lastname: Lemons
authors.forename: M W
authors.initials: MW
authors.lastname: Bidez
mesh_terms: D000704:Analysis of Variance; D001174:Arthrodesis; D001696:Biomechanical Phenomena; D001852:Bone Lengthening; D002348:Carpal Bones / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D013180:Sprains and Strains / Q000503:physiopathology* / Q000601:surgery; D014457:Ulna; D014955:Wrist Joint