A rehabilitation program after anterior cruciate ligament reconstruction is of great importance to obtain a satisfactory prognosis after surgery. However, there is still an onging debate over... Show moreA rehabilitation program after anterior cruciate ligament reconstruction is of great importance to obtain a satisfactory prognosis after surgery. However, there is still an onging debate over whether closed kinetic chain or open kinetic chain exercises should be chosen. Our study was designed to compare the in vivo tibiofemoral kinematics during closed kinetic chain and open kinetic chain exercises. Eighteen healthy volunteers were asked to perform box squat and unloaded/10 kg-loaded seated knee extension. In vivo 3-dimensional analysis of tibiofemoral kinematics of different motions were determined using a dual fluoroscopic imaging system. The study found significantly more tibial anterior displacement during loaded seated knee extension than during unloaded seated knee extension from 25 degrees-50 degrees of knee flexion (p < 0.031). The knees exhibited significantly more internal tibial rotation and lateral tibial translation during the box squat than both seated knee extensions during mid-flexion. In addition, the knees showed less internal-external (IE) range of motion (ROM) from 20 degrees- 75 degrees of flexion (p < 0.001) and medial-lateral (ML) ROM from 75 degrees to full extension (p < 0.006) during box squat than both extensions. This knowledge may help optimize rehabilitation plans for patients post ACL reconstruction. Show less
Unfavorable clinical outcomes after medial patellofemoral ligament (MPFL) reconstruction, such as early osteoarthritis of the patellofemoral joint, were considered to be associate with tunnel... Show moreUnfavorable clinical outcomes after medial patellofemoral ligament (MPFL) reconstruction, such as early osteoarthritis of the patellofemoral joint, were considered to be associate with tunnel malpositioning. Length change studies have found that small changes in the femoral position can cause great changes in elongation trends. Further studying the MPFL kinematics may help us to understand the consequences of tunnel malpositioning and optimize the reconstruction techniques. Fifteen healthy subjects were studied with a combined computed tomography and biplane fluoroscopic imaging technique during a lunge motion. Five femoral and three patellar attachments were used to simulate different MPFL bundles. Kinematics of MPFL was defined as elongation and orientation changes (i.e., deviation angle and elevation angle). The mean deviation angle was 28.7 degrees (95% confidence interval, 28.0 degrees-29.4 degrees) at full extension and remained nearly unchanged up to 60 degrees of flexion, and increased to 56.5 degrees (54.1 degrees-58.9 degrees) at 110 degrees. The elevation angle decreased linearly from 12.6 degrees (9.3 degrees-15.9 degrees) at full extension to -86.2 degrees (-92.7-79.7 degrees) at 110 degrees of flexion. The MPFL was most stretched anteriorly and laterally relative to femur from full extension to 30 degrees of flexion and remained near isometric beyond 30 degrees. The current study found that proximal and anterior femoral attachments caused excessive lateral stretching of the MPFL at deeper flexion angles. Such abnormal MPFL kinematics may subsequently cause overconstraint and increased cartilage pressures of the medial patellofemoral joint. Show less
