Muscle bulk, strength and proprioceptive difference between anterior cruciate ligament deficient and normal knee

Abstract

The anterior cruciate ligament (ACL) deficient knee has been subjected to various research and many conclusions have been drawn to the loss of function in relation to it. ACL reconstruction is also very commonly done as this ligament damage is the most common injury in sports. Muscle strength and proprioception have been postulated to be affected alongside this injury. We conducted a cross sectional study in 19 patients who have ruptured their ACL. We measured their muscle strength, thigh muscle bulk and proprioception in comparison to their contralateral normal knee. The Biodex Isokinetic machine was used to measure the muscle strength and proprioception. The thigh circumference was measured manually using a measuring tape. There was significant reduction of muscle strength and thigh circumference in the ACL deficient limb as compared to the normal side, p < 0.05. The affected knee also showed reduction in proprioceptive ability at 70 degree angle (z score -2.17, p < 0.05), but there was no significant reduction at the other angles. These findings are important as the data show that there is reduction in muscle strength and proprioceptive ability in an ACL deficient knee; hence, rehabilitation addressing these two areas should be emphasized pre-surgery.