SYMPOSIA PAPER Published: 01 January 1987

Isolated Rupture of the Anterior Cruciate Ligament by Knee Hyperflexion


The incidence of anterior cruciate ligament (ACL) tears has increased dramatically in alpine skiing lately. We have studied the injury mechanism of an isolated ACL rupture that occurred in a 36-year-old female skier during a video-taped slalom race. The ACL rupture seemed to occur during a vigorous, weighted knee hyperflexion in a back-sitting skiing position. The skier felt a pop in the hyperflexed knee at that time but was able to ski the next turn which engaged the other leg. When preparing for a new turn engaging the previous hyperflexed knee, she lost control and fell over. Immediate arthroscopy and arthrotomy revealed an isolated complete ACL rupture. Later studies on three cadaver knee specimens displayed a tense ACL in the hyperflexed knee, and the dorsal musculature seemed to act like a fulcrum in this position. It is proposed that weighted knee hyperflexion may cause isolated tears of the ACL.

Author Information

Ekeland, A
Ullevaal Hospital, University of Oslo, Oslo 4, Norway
Thoresen, BO
Ullevaal Hospital, University of Oslo, Oslo 4, Norway
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Developed by Committee: F27
Pages: 61–67
DOI: 10.1520/STP23175S
ISBN-EB: 978-0-8031-5003-4
ISBN-13: 978-0-8031-0936-0