Knee
The effect of patellar button placement on knee balance and bone loading during gait following total knee arthroplasty
Patellar resurfacing is commonly performed as part of TKA. Our study aimed to improve postoperative knee balance by optimizing patellar button positioning. Previous studies focused on the risk of patellar subluxation with results favoring medial placement. We approached this by evaluating muscle forces and patellofemoral stresses during simulated gait.
Objectives:
1. To answer whether button positioning alters muscle forces enough to unbalance the knee.
2. To investigate the effect of button placement and size on button wear and risk of periprosthetic fracture.
We hypothesized that general positioning criteria can be established for gait to reduce the risk of postoperative complications.
Biomechanical analysis of two PCL reconstruction tensioning techniques evaluated with Computerized Lachman Testing
The anterolateral and posteromedial bundle of the posterior cruciate ligament (PCL) contribute to the kinematics of the knee, providing stability and allowing mobility. When the PCL is torn, reconstruction with allograft may be indicated. There have been different techniques described to reconstruct the PCL which include traditional single-bundle and double-bundle techniques. An emphasis has been made to perform an anatomic reconstruction of the two bundles using two femoral tunnels to best recreate native anatomy and kinematics. This study investigates changes in knee laxity after partial and full PCL tearing and after allograft reconstruction (PCLR). The knee laxity is evaluated with computerized Lachman testing using a motion tracking system. We hypothesize that tensioning the allograft at different knee flexion angles impacts the laxity of the knee.
The Effect of Chondral Defect Size and Location on Contact Pressures
Full-thickness chondral defects of the cartilage knee can lead to pain, decreased function and progress towards osteoarthritis. This study examines the biomechanical effects that the location and defect size have on human knees. We investigate how the tibiofemoral contact pressures and contact areas are affected when the size of the chondral defect increases. Also, we compare the effect when the defect is located on the medial and the lateral condyle at full knee extension and 30 degrees of flexion. This study demonstrates that there are significant biomechanical differences in how the medial and lateral femoral condyle experience chondral defects and respond to defects of increasing size. These results may be used to better inform surgical treatment decision-making and cutoffs for the management of chondral defects.