A Relationship Between Gait and Clinical Changes Following High Tibial Osteotomy
By
C.C. Prodromos , T.P. Andriacchi , J.O. Galante
ABSTRACT
We studied the cases of twenty-one patients with high tibial osteotomy in order to determine the relationship between knee-joint loading during gait and clinical outcome. The patients were tested before surgery, one year after surgery, and again at an average of 3.2 years after surgery. An age-matched group of fifteen control subjects was also studied. The results of this study indicate that certain characteristics of preoperative walking are associated with postoperative clinical results. In particular, the moment tending to adduct the knee joint during walking preoperatively was predictive of postoperative clinical results. The patients were classified into a high adduction-moment group and a low adduction-moment group according to the magnitude of the knee-adduction moment. The adduction moment was reduced in both groups after high tibial osteotomy. However, the average postoperative adduction moments in the low adduction-moment group were still significantly lower than those in the high adduction-moment group. The two groups were indistinguishable on the basis of preoperative knee score, initial varus deformity, immediate postoperative correction, age, and weight. However, at an average 3.2-year follow-up, patients with low preoperative adduction moments had substantially better clinical results than did patients with high adduction moments. The low adduction-moment group had 100 per cent excellent or good clinical results, while only 50 per cent of the patients in the high adduction-moment group had an excellent or good result. Furthermore, there was a significant recurrence of varus deformity in the patients in the high adduction-moment group. The geometry of the knee joint measured after realignment of the knee does not predict the dynamic loading that occurs during walking and could not be correlated with clinical results in the study.
CLINICAL RELEVANCE: A low adduction moment at the knee during preoperative gait seems to indicate a beneficial compensatory mechanism that is maintained after high tibial osteotomy. Some of the unpredictability of clinical outcome after high tibial osteotomy may be explainable on the basis of the compensatory style of gait, which is present in some patients but not present in others.