Jorrit Zelle

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BACKGROUND Knee models often do not contain thigh-calf contact which occurs in deep knee flexion. Thigh-calf contact is expected to reduce muscle forces and thereby affects internal stresses in the knee joint. The purpose of this study was to measure thigh-calf contact forces. Two deep knee flexion activities were selected: squatting and kneeling. METHODS(More)
High-flexion knee replacements have been developed to accommodate a large range of motion (RoM > 120°). Knee implants that allow for higher flexion may be more sensitive to femoral loosening as the knee load is relatively high during deep knee flexion, which could result in an increased failure potential at the implant-cement interface of the femoral(More)
Recently, high-flexion knee implants have been developed to provide for a large range of motion (ROM>120 degrees ) after total knee arthroplasty (TKA). Since knee forces typically increase with larger flexion angles, it is commonly assumed that high-flexion knee implants are subjected to larger loads than conventional knee implants. However, most(More)
Aseptic loosening at the implant-cement interface is a well-documented cause of failure in joint arthroplasty. Traditionally, the strength of the implant-cement interface is determined using uni-axial normal and shear loading tests. However, during functional loading, the implant fixation sites are loaded under more complex stress conditions. For this(More)
High-flexion total knee arthroplasty (TKA) may be more sensitive to femoral loosening than conventional TKA as the knee joint force increases during deep flexion. The objective of this study was to evaluate whether the probability of femoral loosening is equal in posterior cruciate ligament (PCL) retaining and substituting high-flexion knee implants and(More)
Total knee arthroplasty (TKA) is a widely used and successful orthopaedic procedure. During TKA, the posterior cruciate ligament (PCL) can either be retained or substituted by a post-cam mechanism. One of the main functions of the PCL is to facilitate femoral rollback during knee flexion. For adequate PCL functioning, the PCL should be balanced correctly(More)
BACKGROUND We compared the functional outcome between conventional and high-flexion total knee arthroplasty (TKA) using kneeling and sit-to-stand tests at 1 year post-operative. In addition, the patient's daily functioning, pain and satisfaction were quantified using questionnaires. METHODS We randomly assigned 56 patients to receive either a conventional(More)