title: The Effect of Distal Location of the Volar Short Arm Splint on the Metacarpophalangeal Joint Motion.
abstract: BACKGROUND
  The goals of this study were to compare maximal metacarpophalangeal joint (MCPJ) flexion angles after application of a volar short arm splint at 3 different locations and verify the relations between the three different physical and radiological locations.
  
  
  METHODS
  Forty dominant hands of healthy subjects were analyzed in the study. We defined a transverse skin folding line as a line drawn from the radial aspect of the thenar crease to the ulnar aspect of the distal transverse palmar crease. The distal end of the volar short arm splint was applied on 3 parallel locations to this line. Location A was on this transverse skin folding line; location B was 1 cm proximal to location A; and location C was 1 cm distal to location A. Two orthopedic surgeons measured the maximal MCPJ flexion angles of each finger except the thumb with the application of a volar short arm splint at 3 different locations as well as without a splint as a control. Radiological locations of the 3 different distal ends of the volar short arm splint were also assessed by anteroposterior radiographs of the wrist.
  
  
  RESULTS
  When the splint was applied at location A and C, the maximal MCPJ flexion angle decreased to a mean of 83° (91% of control value) and 56° (62% of control value), respectively (compared to the control, p < 0.001). At location B, the maximal MCPJ flexion angle was a mean of 90° (99% of control value); no significant difference was observed compared to the control or without the splint (p = 0.103). On radiography, the average length from the metacarpal head to the distal end of the splint at all fingers decreased in the order of location B, A, and C (29 mm, 19 mm, and 10 mm, respectively; p < 0.001).
  
  
  CONCLUSIONS
  We recommend applying the distal end of a volar short arm splint at proximal 1 cm to the transverse skin folding line to preserve MCPJ motion perfectly, which is located at distal 44% of the whole metacarpal bone length radiologically.
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Joon Yub
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Sohn
authors.affiliation: Department of Orthopedic Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea.
authors.forename: Ho Youn
authors.initials: HY
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Yoo
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Joo Hak
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Myung Gon
authors.initials: MG
authors.lastname: Jung
authors.affiliation: Department of Orthopedic Surgery, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Cho
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008662:Metacarpophalangeal Joint / Q000502:physiology*; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology*; D013165:Splints; D055815:Young Adult
keywords: Joint range of motion; Metacarpophalangeal joint; Splint