Noriyuki Takasu

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.

Clinical Results of Rotational Acetabular Osteotomy

We performed rotational acetabular ostetomy (RAO) on 14 patients. All subjects were women, their ages at surgery ranged from 25 to 52 years, and the follow-up period averaged 4 years. We compared the CE angle and AC angle before and after surgery.All patients showed improvement of both the CE angle and AC angle. The mean CE angle improved from 4.4 degrees to 24.6 degrees (p<0.01), and the mean AC angle from 23.8 degrees to 8.3 degrees (p<0.01). The range of motion (flexion and abduction) did not decrease alter surgery. 1 patient showed progression of the degenerative change by the necrosis of the rotated bone.The clinical results for RAO were not significant compared to early stage OA (11 hips) and advanced OA (4 hips).

Clinical Results of Bilateral Total Knee Arthroplasties Comparison of Simultaneous and Staged Knee Replacements

The purpose of this study was to evaluate outcome of bilateral total knee arthroplasties (TKAs) in two groups of patients: Group A had simultaneous arthroplasty of both knees, and Group B had staged bilateral arthroplasty.Bilateral (TKAs) were performed in fifteen patients with severe rheumatoid arthritis (4 cases) and osteoarthritis (11 cases). Group A (8 patients) had both knees replaced simultaneously in one operation. Group B (7 patients) had two operation in a staged procedure. The postoperative mobility was analyzed in the two groups of patients who were similar with respect to age, type of arthritis, preoperative range of motion, and postoperative management.In this small series of cases there was a significantly shorter hospitalization period, and cheaper costs in Group A.