Anterior cruciate ligament replacement. Knee stability and the effects of implants.
The anteroposterior stability of cadaveric knees was investigated. There was a wide range of normal laxity; knees were more stable at 90 degrees than at 20 degrees flexion. Anterior cruciate ligament implants with different stiffnesses were inserted; normal stability could always be restored, and the stiffness or extensibility of implants did not affect knee behaviour significantly. The tightness of implants was critical--small tensioning errors caused subluxation, inhibited knee extension and allowed damagingly high implant tensions. It is concluded that the tension of ligament implants could not be adjusted simply with a pre-set instrument; the procedure will remain critically dependent on the judgment of the operating surgeon.
Amis
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Mechanical Engineering Department, Imperial College of Science, Technology and Medicine, London, England.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D002244:Carbon; D000077482:Carbon Fiber; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control*; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D008023:Ligaments, Articular / Q000502:physiology / Q000601:surgery*; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods; D008875:Middle Aged; D011091:Polyesters; D019736:Prostheses and Implants
D000077482:Carbon Fiber; D011091:Polyesters; D002244:Carbon