title: In Vivo Scaphoid Motion During Thumb and Forearm Motion in Casts for Scaphoid Fractures.
abstract: OBJECTIVE
  In nonsurgical treatment for acute undisplaced or minimally displaced scaphoid waist fractures, immobilization of both wrist and thumb can be an option. However, in vivo scaphoid motion during forearm and thumb motion with the wrist immobilized in a cast has not been measured. Therefore, we examined the in vivo kinematics of the scaphoid during forearm and thumb motion with cast immobilization.
  
  
  METHODS
  Ten healthy right wrists of 10 male volunteers were included. These wrists were immobilized in a short-arm spica cast with the thumb in a position of volar abduction and then were scanned with the forearm in supination, neutral rotation, and pronation using computed tomography. Next, these wrists were scanned with a forearm gauntlet cast in place with the thumb abducted radially and opposed with the forearm positioned in neutral rotation. From these data, the 3-dimensional position of the third metacarpal and scaphoid was analyzed.
  
  
  RESULTS
  From forearm supination to pronation, the scaphoid showed 0.2° radial deviation, 0.4° pronation, and 8.3° extension. The third metacarpal showed 14.6° ulnar deviation, 6.5° pronation, and 1.6° flexion. During thumb opposition from radial abduction, the scaphoid showed 2.9° radial deviation, 0.4° supination, and 7.2° extension and the third metacarpal showed 4.5° ulnar deviation, 2.8° pronation, and 5.5° extension.
  
  
  CONCLUSIONS
  The scaphoid was not completely immobilized by either cast. However, the scaphoid motion during forearm and thumb motion was not significant.
  
  
  CONCLUSIONS
  Several high-quality studies have shown that undisplaced or minimally displaced scaphoid waist fractures can be successfully treated with casts. Movement of scaphoid and wrist during forearm rotation or thumb motion with a cast may not be sufficient to have a negative impact on the outcome of scaphoid fracture using a cast.
authors.affiliation: Department of Orthopedic Surgery, Itami City Hospital, Itami, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kawanishi
authors.affiliation: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan. Electronic address: oka-kunihiro@umin.ac.jp.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Oka
authors.affiliation: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Orthopedic Biomaterial Science, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Sugamoto
authors.affiliation: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Murase
mesh_terms: D000328:Adult; D002370:Casts, Surgical; D005542:Forearm / Q000503:physiopathology*; D050723:Fractures, Bone / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D011403:Pronation / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D021361:Scaphoid Bone / Q000293:injuries*; D013484:Supination / Q000502:physiology; D013933:Thumb / Q000503:physiopathology*
keywords: 3-dimensional analysis; Colles cast; scaphoid fracture; thumb spica cast