Injury to the anterior cruciate ligament during alpine skiing: a biomechanical analysis of tibial torque and knee flexion angle.
BACKGROUND
The anterior cruciate ligament has been shown to be particularly susceptible to injury during alpine skiing. Tibial torque is an important injury mechanism, especially when applied to a fully extended or fully flexed knee.


OBJECTIVE
We wanted to record the forces generated in the anterior cruciate ligament with application of tibial torque to cadaveric knees in different positions.


METHODS
Controlled laboratory study.


METHODS
Thirty-seven fresh-frozen cadaveric knees were instrumented with a tibial load cell that measured resultant force in the anterior cruciate ligament while internal and external tibial torques were applied to the tibia at full extension, 90 degrees of flexion, full flexion, and forced hyperflexion.


RESULTS
At each knee flexion position, mean force generated by 10 N.m of internal tibial torque was significantly higher than the mean generated by 10 N.m of external tibial torque. Mean forces generated by tibial torque at 90 degrees of flexion were relatively low. During flexion-extension without tibial torque applied mean forces were highest (193 N) when the knee was hyperflexed.


CONCLUSIONS
Application of internal tibial torque to a fully extended or fully flexed knee represents the most dangerous loading condition for injury from twisting falls during skiing.


CONCLUSIONS
Understanding of the mechanisms of falls can be used to design better equipment and to better prevent or treat injury.
Biomechanics Research Section, Department of Orthopaedic Surgery, University of California Los Angeles School of Medicine, Los Angeles, California 90095, USA.
Sharon L
SL
Hame
Daniel A
DA
Oakes
Keith L
KL
Markolf
D000058:Accidental Falls; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D006801:Humans; D007718:Knee Injuries / Q000209:etiology / Q000503:physiopathology*; D008875:Middle Aged; D012421:Rupture; D012865:Skiing / Q000293:injuries*; D013977:Tibia / Q000503:physiopathology; D019415:Torque