Tetsuya Otsuka

Gait Analysis of Unilateral Total Hip Replacement: Quantitative Analysis of the Vertical Floor Reaction Force

The subjects of this study were 31 patients, all female, with an average age of 60.1 years, who had had unilateral total hip replacement due to osteoarthrosis of the hip joint. Ten Charnley’s low friction arthroplasties and 21 Omnifit systems were implanted from 1984 to 1990, and the mean follow-up period was 5.0 years. Gait studies were conducted on a walkway to measure the floor reaction force at free speed without the use of canes or crutches. Multiple regression analysis was applied to the recorded data and various parameters were obtained for the quantitative evaluation of gait, both pre- and postoperatively, in patients who had received total hip replacements (THR). We found that the similarity index for the “weighing-off” effect reached the highest value in the 3 years after surgery, and then decreased gradually during the follow-up period. The gain in the similarity index of acceleration effect was also significant in the 3 years after operation. The recovery of the index value was more rapid in patients with the Omnifit (Osteonics Corp., Allendale, N.J.) type than in these with the Charnley (Charnley’s Low Friction Arthroplasties, Thackray Ltd., London, England) type THR. For the kinesiological and quantitative evaluation of THR patients pre- and postoperatively, gait analysis, using measurements of the floor reaction force, appears to be a suitable technique for long-term follow-up.