KNEE-JOINT LOADING AND TIBIAL COMPONENT LOOSENING

We report a prospective study of gait and tibial component migration i n 45 patients with osteoarthritis treated by total knee arthroplasty ( TKA). Migration was measured over two years using roentgen stereophoto grammetry. We used the previously established threshold of 200 mu m mi gration in the second postoperative year to distinguish two groups: a risk group of 15 patients and a stable group of 28 patients. We perfor med gait analysis before operation and at six months and at two years after TKA, On all three occasions we found significant differences bet ween the two groups in the mean sagittal plane moments of the knee joi nt. The risk group walked with higher peak flexion moments than the st able group. The two groups were not discriminated by any clinical or r adiological criteria or other gait characteristics. The relationship w hich we have found between gait with increased flexion moments and ris k of tibial component loosening warrants further study as regards the aetiology of prosthetic loosening and possible methods of influencing its incidence.