Abstract
The purpose of this study was to determine the relative contribution of muscle activity
and the effect of forearm position on the stability of the medial collateral ligament
(MCL)-deficient elbow. Simulated active and passive elbow flexion with the forearm
in both supination and pronation was performed using a custom elbow testing apparatus.
Testing was first performed on intact specimens, then on MCL-deficient specimens.
Elbow instability was quantified using an electromagnetic tracking device by measuring
internal-external rotation and varus-valgus laxity of the ulna relative to the humerus.
Compared with the intact elbow, transection of the MCL, with the arm in a vertical
orientation, caused a significant increase in internal-external rotation during passive
elbow flexion with the forearm in pronation, but forearm supination reduced this instability.
Overall, following MCL transection the elbow was more stable with the forearm in supination
than pronation during passive flexion. In the pronated forearm position simulated
active flexion also reduced the instability detected during passive flexion, with
the arm in a varus and valgus gravity-loaded orientation. The maximum varus-valgus
laxity was significantly increased with MCL transection regardless of forearm position
during passive flexion. We concluded that active mobilization of the elbow with the
arm in vertical orientation during rehabilitation is safe in the setting of an MCL-deficient
elbow with the forearm in a fully supinated and pronated position. Splinting and passive
mobilization of the MCL-deficient elbow with the forearm in supination should minimize
instability and valgus elbow stresses should be avoided throughout the rehabilitation
period. (J Hand Surg 2000;25A:1051-1057. Copyright © 2000 by the American Society
for Surgery of the Hand.)
Keywords
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Article info
Publication history
Accepted:
May 16,
2000
Received:
November 18,
1999
Footnotes
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
**Reprint requests: Graham J.W. King, MD, Hand and Upper Limb Centre, 268 Grosvenor St, London, Ontario, Canada N6A 4L6.
Identification
Copyright
© 2000 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
