title: Thumb duplication at the metacarpophalangeal joint. Management and a new classification.
abstract: Duplication at the metacarpophalangeal joint level (Wassel Type IV) is the most common type thumb duplication (polydactyly), accounting for 50%. It can be subdivided into 4 types: (A) hypoplastic (12%), (B) ulnar deviated (64%), (C) divergent (15%), and (D) convergent (complex) (9%). Type D has the most complex bone and soft tissue anomalies and is most likely to have residual deformities. A surgical protocol emphasizing early operation within 1 year of age, 1 stage osteotomy, meticulous collateral ligament repair, and abductor pollicis brevis tendon reattachment is presented. Twenty-one cases with an average followup of 5.25 years were reviewed. The cosmetic and functional results were satisfactory. Of a score system of 20 points, the mean score was 17.9. All except 1 patient had a stable metacarpophalangeal joint. Fifteen patients had a good range of movement, and 17 patients are satisfied with the outcome of surgery. Scar hypertrophy occurred in 2 patients.
authors.affiliation: Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin.
authors.forename: L
authors.initials: L
authors.lastname: Hung
authors.forename: J C
authors.initials: JC
authors.lastname: Cheng
authors.forename: R
authors.initials: R
authors.lastname: Bundoc
authors.forename: P
authors.initials: P
authors.lastname: Leung
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D017746:Joint Capsule / Q000601:surgery; D008297:Male; D008662:Metacarpophalangeal Joint / Q000601:surgery; D017060:Patient Satisfaction; D017689:Polydactyly / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D013710:Tendons / Q000601:surgery; D013933:Thumb / Q000002:abnormalities* / Q000000981:diagnostic imaging; D016896:Treatment Outcome