STRESSES AT THE IMPLANT-BONE INTERFACE IN TOTAL KNEE REPLACEMENT.

Short term failure of total knees can occur due to serious misalignment, instability, or infection. In the long-term however, the most common failure mechanism is loosening, which is characterised by resorption and remodelling of bone at the interface. The probable causes include implant-bone micromotion, abnormal stresses on the bone, and biological reactions at the interface. This paper considers the stresses at the interface, on an overall and on a trabecular scale. There are a number of factors in the design of the implant, in the surgical technique, and in the design of the interface itself, which can minimise abnormal stresses and produce a more normal stress pattern.