title: Stability of the Basal Joints of the New Thumb After Pollicization for Thumb Hypoplasia.
abstract: OBJECTIVE
  To investigate the presence or absence of union of the new trapezium to the retained metacarpal base after pollicization and to relate this to stability of the new trapezium and the new carpometacarpal joint.
  
  
  METHODS
  Thirty-six patients (46 pollicizations) were assessed at clinical review. Mean time from surgery to review was 96 months (range, 9-260 mo). Clinical assessment measured range of motion (ROM) at the carpometacarpal joint, stability of the carpometacarpal joint, and extrinsic and intrinsic strength of both hands. Radiological review evaluated 3 parameters: bony union between the new trapezium and retained metacarpal base, stability of the new trapezium in relationship to the metacarpal base, and carpometacarpal joint stability.
  
  
  RESULTS
  There was radiographic nonunion between the new trapezium and the retained metacarpal base in 8 (1 treated) of 46 pollicizations. Relative risk of instability of the new trapezium was 39 times more likely if nonunion was present. Nine pollicizations were unstable at the carpometacarpal joint, 8 in those with union and 1 with nonunion. Relative risk of instability was 1.4 times more likely for those with union. For patients with nonunion, ROM and grip strength variables were reduced but only grip strength reached statistical significance. In patients with carpometacarpal joint instability, ROM and grip strength variables were reduced but none of the variables reached statistical significance.
  
  
  CONCLUSIONS
  This study suggests that when the surgeon is attempting to obtain union of the new trapezium to the retained metacarpal base, failure to do so results in a poorer thumb with a significantly increased risk of trapezial instability and decreased grip strength. There is a mildly increased risk of carpometacarpal joint instability with union, but significantly poorer function as a consequence of this has not been demonstrated.
  
  
  METHODS
  Therapeutic IV.
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Trist
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia. Electronic address: mtonkin@med.usyd.edu.au.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Tonkin
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: van der Spuy
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
authors.forename: Albert
authors.initials: A
authors.lastname: Yoon
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
authors.forename: Harvinder P
authors.initials: HP
authors.lastname: Singh
authors.affiliation: Department of Hand Surgery and Peripheral Nerve Surgery, Royal North Shore Hospital, Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Lawson
mesh_terms: D000293:Adolescent; D052737:Carpometacarpal Joints / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007223:Infant; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D013933:Thumb / Q000002:abnormalities*; D051222:Trapezium Bone / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
keywords: Pollicization; carpometacarpal joint instability; function; trapezium instability