Tibial loading after UKA: evaluation of tibial slope, resection depth, medial shift and component rotation

With increased precision in alignment offered by new generations of instrumentation and customized guides, this study was designed to establish a biomechanically-based target alignment for the balance of tibial loading in order to diminish the likelihood of pain and subsidence related to mechanical overload post-UKA. Sixty composite tibias were implanted with Oxford UKA tibial components with varied sagittal slope, resection depth, rotation and medial shift using patient matched instrumentation. Digital image correlation and strain gage analysis was conducted in static loading to evaluate strain distribution as a result of component alignment. In this model, minimal distal resection and most lateral positioning, neutral component rotation, and 3° of slope (from mechanical axis) exhibited the most balanced strain response to loading following UKA.