Paul S C Malone1, John Cooley2, Giorgio Terenghi3, Vivien C Lees4. 1. Blond McIndoe Laboratories for Plastic Surgery Research, University of Manchester, Manchester, UK; Department of Plastic and Reconstructive Surgery, University Hospital South Manchester Trust, Wythenshawe, UK. 2. University of Manchester, Manchester, UK; Department of Research & Development, University Hospital South Manchester Trust, Wythenshawe, UK. 3. Blond McIndoe Laboratories for Plastic Surgery Research, University of Manchester, Manchester, UK. 4. Blond McIndoe Laboratories for Plastic Surgery Research, University of Manchester, Manchester, UK; Department of Plastic and Reconstructive Surgery, University Hospital South Manchester Trust, Wythenshawe, UK. Electronic address: vivienlees@live.com.
Abstract
PURPOSE: To investigate the hypothesis that elbow extension alters the biomechanics of forearm rotation including force transmission in the distal and proximal radioulnar joints (DRUJ and PRUJ) and the interosseous ligament (IOL). METHODS: A cadaver model with a custom-designed jig was used to measure forearm pronosupination ranges, transmitted forces and contact areas across the PRUJ and DRUJ, and tension in the 3 main components of the IOL's central band. Testing with applied loads was undertaken throughout pronosupination with the elbow fully flexed (n = 15) and fully extended (n = 11). RESULTS: Elbow extension-flexion affected the range of forearm pronosupination, shifting the arc of rotation such that the forearm supinated maximally with the elbow flexed and pronated maximally with the elbow extended. Elbow extension also increased transmitted forces across the DRUJ and PRUJ while also increasing contact areas within the DRUJ and PRUJ. Elbow extension significantly increased tension in the central band of the IOL when the forearm was maximally pronated. CONCLUSIONS: Maximum supination occurred with the elbow flexed. Maximum pronation occurred with it extended. Elbow position altered forearm biomechanics, including force transmission across the PRUJ and DRUJ and transmitted tension in the IOL. CLINICAL RELEVANCE: The interplay of osseoligamentous forearm structures is such that we would anticipate surgical alteration of any one of them to have effects upon function of the others.
PURPOSE: To investigate the hypothesis that elbow extension alters the biomechanics of forearm rotation including force transmission in the distal and proximal radioulnar joints (DRUJ and PRUJ) and the interosseous ligament (IOL). METHODS: A cadaver model with a custom-designed jig was used to measure forearm pronosupination ranges, transmitted forces and contact areas across the PRUJ and DRUJ, and tension in the 3 main components of the IOL's central band. Testing with applied loads was undertaken throughout pronosupination with the elbow fully flexed (n = 15) and fully extended (n = 11). RESULTS: Elbow extension-flexion affected the range of forearm pronosupination, shifting the arc of rotation such that the forearm supinated maximally with the elbow flexed and pronated maximally with the elbow extended. Elbow extension also increased transmitted forces across the DRUJ and PRUJ while also increasing contact areas within the DRUJ and PRUJ. Elbow extension significantly increased tension in the central band of the IOL when the forearm was maximally pronated. CONCLUSIONS: Maximum supination occurred with the elbow flexed. Maximum pronation occurred with it extended. Elbow position altered forearm biomechanics, including force transmission across the PRUJ and DRUJ and transmitted tension in the IOL. CLINICAL RELEVANCE: The interplay of osseoligamentous forearm structures is such that we would anticipate surgical alteration of any one of them to have effects upon function of the others.