Biomechanical changes of the wrist flexor and extensor tendons following loss of scaphoid integrity
Autor: | Shohei Omokawa, Jaiyoung Ryu, Jin Bo Tang, Vincent Kish, Stanley Wearden, JungSoo Han |
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Rok vydání: | 1997 |
Předmět: |
Joint Instability
Male musculoskeletal diseases Scaphoid fracture Wrist Tendons Fractures Bone Extensor Carpi Radialis Brevis Cadaver medicine Extensor Carpi Ulnaris Humans Orthopedics and Sports Medicine Carpal Bones Aged Carpal Joint business.industry Anatomy Middle Aged musculoskeletal system medicine.disease Biomechanical Phenomena Tendon body regions medicine.anatomical_structure Female Extensor Carpi Radialis Longus Cadaveric spasm business |
Zdroj: | Journal of Orthopaedic Research. 15:69-75 |
ISSN: | 1554-527X 0736-0266 |
Popis: | Loss of integrity of the scaphoid may change the motion center of the entire carpus, and deformities from scaphoid fractures may alter the location of motor tendons of the wrist, thus altering their biomechanics. The goal of this study was to clarify biomechanical changes in these tendons following loss of scaphoid integrity. Excursions and moment arms of the principal flexor and extensor tendons of the wrist were investigated in seven cadaveric upper extremities in intact wrists after simulation of scaphoid waist fracture and after removal of the proximal scaphoid. Excursions of the flexor carpi radialis and ulnaris, extensor carpi radialis longus and brevis, and extensor carpi ulnaris tendons were measured with rotary potentiometers during wrist flexion-extension and radioulnar deviation. Simultaneously, wrist joint angulation was recorded. Moment arms of the tendons were derived from tendon excursions and joint motion. After scaphoid fracture, the moment arms of the flexor carpi radialis and extensor carpi ulnaris tendons increased significantly during wrist flexion-extension, whereas the moment arms of the extensor carpi radialis longus and brevis tendons decreased significantly. After proximal scaphoid excision, the moment arms of the extensor carpi radialis longus and brevis tendons again decreased significantly during wrist flexion-extension. The moment arms of the flexor carpi radialis and extensor carpi radialis brevis tendons increased significantly during radioulnar deviation, whereas those of the wrist motors on the ulnar side decreased. These findings indicate the importance of the integrity of the scaphoid in maintaining normal biomechanics of motor tendons of the wrist. An increase in the moment arm of the radial wrist flexor along with a decrease in moment arms of the radial extensors constitutes as etiology for persistent angulation of the scaphoid and the humpback deformity. In addition, disturbing the biomechanics of the wrist motor tendons predisposes the carpal joints to abnormal loading, potentially contributing to the development of carpal joint degeneration. |
Databáze: | OpenAIRE |
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