Comparing Changes in Knee Muscle Strength after Reconstruction of the Anterior and Posterior Cruciate Ligaments

Abstract

Purpose:The purpose of this study was to identify changes in knee muscle strength after reconstruction of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). Methods: Thirteen subjects (males) with anterior ligament injury and ten subjects (males) with posterior ligament injury voluntarily participated in this study. Both groups were evaluated at the pre-and post-reconstruction stages using an isokinetic dynamometer. Peak torque, total work, and the hamstrings to quadriceps (H/Q) peak torque ratio were calculated at angular velocities of 60°/sec and 180°/ sec. Statistical analysis was conducted on SPSS 18.0 for Windows using t-tests to compare mean differences. Results: At an angular velocity of 60°/sec, both the ACL and PCL groups showed a significant increase in muscle strength in the flexors and extensors. Muscle strength in the extensors was significantly increased in the PCL group compared to the ACL group. At an angular velocity of 180°/sec, the ACL group showed a significant increase in muscle endurance in the flexors and extensors, and the PCL group showed a significant increase in muscle endurance in the flexors. At angular velocities of 60°/sec and 180°/sec, the H/Q peak torque ratio increased in the ACL group but decreased in the PCL group. Consequently, the H/Q peak torque ratio was significantly different for the two groups. Conclusion: The results suggest that the patients with ACL injury should focus on strengthening the knee extensors and that the patients with PCL injury need to strengthen the knee flexors. Keywords: Anterior cruciate ligament, Posterior cruciate ligament, Muscle strength stability against varus, valgus, and external rotation. 9 Hughston et al. 10 have emphasized the importance of the PCL as a critical stabilizer of the knee joint. Anterior cruciate ligament injuries are divided into contact injuries and noncontact injuries. About 70-80% of ACL injuries are noncontact injuries, whereas only 20-30% are contact injuries. 11 Noncontact injuries are caused by single-foot landing, direct deceleration, and pivoting, twisting, and cutting movements without direct physical contact. 12 Noncontact injuries, on the other hand, are often accompanied by injuries of the medial meniscus and medial collateral ligament which are caused by strong varus external forces. 13The PCL has two major injury mechanisms. The first occurs during posterior translation of the proximal tibial bone when the knee joint is bent. Most injuries are caused by serious impact on the antero-proximal tibia (dashboard injury) due to traffic accidents and by falling when the knee joint is bent during sports activities. 14,15 The second mechanism occurs when excessive force is exerted on the PCL during forced over-flexion or extension of the knee joint. 16,17 Cruciate ligament injuries cause various problems in the knee joint and its periphery. Anterior cruciate ligament injury may lead to knee joint pain, instability, and secondary osteoarthritis of the knee. It can also cause serious impairment...

Diagnostic Accuracy of Clinical Test for Anterior Cruciate Ligament Injury: Systematic Review

“…3 The ACL is momentous in stabilizing the knee joint by resisting anterior tibial translation. 2,[4][5][6][7] When the knee is in extension the ACL provided 75% of the resistance to the forward movement of the tibia and 85% of the resistance at 30-90 degrees of flexion. 8 The incidence of ACL rupture has been noticed as 3 per 100.00 sedentary person and in professional athletes has been reported as 3.7 per 100.…”