Jan-Ragnar Haugstvedt

Mayo Clinic - Rochester, Rochester, Minnesota, United States

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Publications (2)3.14 Total impact

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    ABSTRACT: Laboratory studies evaluating the importance of the stabilizing structures of the distal radioulnar joint (DRUJ) largely have been limited to static design. Clinically, dynamic loading seems to be an important component of DRUJ instability. This study was designed to evaluate the influence of dynamic loading on the stability of the DRUJ with foveal versus styloid triangular fibrocartilage complex (TFCC) disruptions in a laboratory setting. Twelve fresh-frozen cadaveric upper-extremity specimens were tested using a dynamic simulator to study the contributions of the 2 ulnar insertions of the TFCC to the dynamic stability of the DRUJ. The specimens were tested in 3 loading conditions (no load, agonist loading, antagonist loading) in 3 different states of the TFCC (intact, foveal disruption, styloid disruption). Without load no significant differences were found for the different conditions of the TFCC. Under loaded conditions the foveal insertion had a greater effect on stability than did the styloid insertion. Under agonist loading significant differences were found during supinating and pronating motions. With antagonist loading a significant difference was found only during supination. The study results support the clinical impression that dynamic loading is an important component of DRUJ instability and that disruption of the foveal TFCC insertion into the foveal region of the distal ulna can produce instability.
    The Journal Of Hand Surgery 04/2006; 31(3):445-51. · 1.57 Impact Factor
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    ABSTRACT: Nine cadaver upper extremities were tested to evaluate the constraint properties of the dorsal and palmar radioulnar ligaments at their foveal and styloid attachments to the ulna. The specimens were tested by anterior and posterior displacement of the radius relative to the ulna with the forearm in pronation, supination, and neutral rotation. There were no statistically significant differences in the relative percent of constraint contribution of the styloid and foveal ligament insertions. In neutral forearm rotation total displacement after sectioning both ligament insertions tended to be larger in palmar than in dorsal displacement. A similar trend was observed with 60 degrees forearm supination. In the pronated position, however, the trend was reversed with larger total displacement in dorsal displacement.
    The Journal Of Hand Surgery 02/2002; 27(1):61-7. · 1.57 Impact Factor