Fractional Dolphin Tenotomy for Boutonniere Deformity: A Cadaveric Study.

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Abstract

Conflict of interest statement: No benefits in any form have been received or will be received related directly to this article. 17. J Hand Surg Am. 2018 Jan;43(1):80.e1-80.e6. doi: 10.1016/j.jhsa.2017.07.011. Epub 2017 Sep 7. Biomechanics of the Acute Boutonniere Deformity. Grau L(1), Baydoun H(2), Chen K(2), Sankary ST(3), Amirouche F(2), Gonzalez MH(4). Author information: (1)Department of Orthopaedics, Miami, FL. (2)Department of Orthopaedics, University of Illinois College of Medicine, Chicago, IL. (3)University of Miami Miller School of Medicine, Miami, FL. (4)Department of Orthopaedics, University of Illinois College of Medicine, Chicago, IL. Electronic address: hiphand15@gmail.com. PURPOSE: To demonstrate which structures of the extensor mechanism create a boutonniere deformity, when damaged, in a cadaver model. An analysis of how damage to these anatomical structures affects the biomechanical performance of the extensor mechanism was also performed. METHODS: We secured 18 fresh cadaveric hands onto an apparatus consisting of a computer-controlled motor and tensiometer attached in series to the extensor communis tendon of the ring and middle digits. The central slip, transverse, and oblique fibers of the interosseous hood and the triangular ligament were sequentially divided. After each structure was divided, the motors were activated to provide a constant tendon displacement force. The angular displacement at the proximal interphalangeal (PIP) and distal interphalangeal joints was recorded. RESULTS: In all digits, detachment of the central slip from the middle phalanx produced a decrease in extension of the PIP joint. When the transverse and oblique fibers of the interosseous hood were also divided, extension at the PIP joint was further decreased. A boutonniere deformity occurred only when all 3 structures were damaged. CONCLUSIONS: The boutonniere deformity requires subluxation of the lateral bands volar to the axis of rotation of the PIP joint. This study demonstrates that damage to the central slip alone does not cause the deformity. Combined injury of the central slip, triangular ligament, and transverse and oblique fibers of the interosseous hood causes a boutonniere deformity. CLINICAL RELEVANCE: Division of the central slip leads to loss of extension at the PIP joint. A more substantial loss of extension after injury or development of a boutonniere deformity should alert clinicians that other structures of the extensor mechanism are also damaged. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved. DOI: 10.1016/j.jhsa.2017.07.011