Exploring the benefits of a 3D patient-specific aligned total knee arthroplasty

People with end-stage osteoarthritis are frequently treated with a total knee arthroplasty (TKA) when all conservative therapies such as NSAIDs and physiotherapy fail. Surgical techniques, arthroplasty designs and alignment methods evolve rapidly showing good functional outcomes in many patients. However, despite these growing insights, an important amount of patients (up to 20%) remains dissatisfied after surgery due to persisting pain and less good functional outcomes as expected (Nashi, et al. 2015). Optimizing the alignment strategy and the implementation of a more patient-specific alignment might be a key factor in optimizing clinical and functional outcome. In mechanical alignment procedures, which is currently still the golden standard, one strives to create a postoperative hip-knee-ankle angle (HKA) of 180° in every patient, allowing a deformity of 3° off neutral (177°-183°). With the advent of robot-assisted knee arthroplasty, more patient specific alignment strategies are now possible (eg kinematic alignment, inverse kinematic alignment, individualized alignment). Winnock de Grave et al. (2020) stated that choosing for an inverse kinematic alignment (iKA) results in better functionality scores compared to a mechanical alignment (MA) (Winnock de Grave, et al. 2020). In this procedure, native coronal alignment is restored postoperatively (with maximal limits of HKA ranging 174° to 183°) which might be beneficial for soft tissue strain and biomechanical function. Optimizing implant position may not be limited to the frontal plane alone. Current progress in surgical techniques with the use of robot-assisted navigation, allow the implementation of patient-specific 3D position of the implant (Lonner and Fillingham 2018). Apart from the coronal plane, also the axial and the sagittal plane can be addressed more accurately. This method might enable a much more optimal balance of the soft tissues and knee ligaments (e.g., posterior cruciate ligament) which might be beneficial for biomechanical function of the knee and patient reported outcome measures. Therefore, the aim of this thesis is to explore whether an individualized 3D approach toward component position and joint balancing in total knee arthroplasty results in better joint function for the patient. Therefore biomechanical analyses evaluating joint kinematics and kinetics during functional movements such as gait, stair climbing, stair descending, sit to stand and kneeling in patients receiving a mechanically aligned and a 3D patient specific aligned total knee arthroplasty will be investigated.