Could passive knee laxity be related to active gait mechanics? An exploratory computational biomechanical study using probabilistic methods

Improving total knee replacement (TKR) requires better understanding of the many factors influencing clinical outcomes. Recently, probabilistic studies have investigated the influence of variability for individual TKR activities. This study demonstrates conceptually how probabilistic studies might further provide a framework to explore relationships not just within but between multiple different activities, e.g. intra-operative passive laxity drawer loading and post-operative active gait. Two implants were compared using simulated ISO-gait and passive laxity loading, with factors including mal-positioning and soft-tissue constraint varied using Monte-Carlo analysis. The results illustrate that correlations between different activities can be quantified; this demonstration study suggests further research is justified (with detailed clinically representative models) to explore the relationship between passive and active mechanics for specific in vivo conditions. Probabilistics is a key enabling methodology for achieving this goal. In future, exploring correlations between different activities may facilitate a better holistic understanding of TKR function.