Effect of post-rehabilitation exercise on strength and postural stability following total hip arthroplasty

Patients with total hip arthroplasty (THA) are treated by physical therapists during the acute phase of their recovery, and their treatment consists mainly of self-care instructions and a standard exercise protocol that emphasizes mobility. The literature suggests that strength and postural stability impairments are present in patients who have undergone THA 1 to 2 years previously. However, little is written about the outcomes of physical therapy programs instituted later in the recovery from THA. The purpose of this study was to investigate the effects of a post-rehabilitation exercise program for patients who had undergone THA. Twenty-eight subjects with a mean age of 59.5 years ( SD = 11.2) who had THA 4-12 months previously were randomly assigned to one of two exercise groups. The control group (n = 14) received basic isometric and active ROM exercises while the experimental group (n = 14) received strength and postural stability training exercises. Assessments of self-perceived function, fear of falling, muscle strength, and postural stability were performed before and after the 8-week home exercise intervention. The Wilcoxon Signed Ranks, used to test for significance of pre- and post-exercise differences on the hip questionnaire scores, revealed statistically significant differences for the experimental group but not the control group. A McNemar change test revealed that differences in responses to questions about fear of falling pre- and post-exercise were not significant for either group. A 2 x 2 repeated measures multivariate analysis of variance (MANOVA) used to test pre- and post-exercise differences between and within groups on the strength and postural stability variables revealed a statistically significant group by pre-post test interaction. The multivariate related samples t -test used to test for simple main effects of pre-post differences revealed that differences were significant only for the experimental group. Univariate paired samples t -tests used to test differences between pre- and post-exercise measurements for each muscle strength and postural stability variable in the experimental group, demonstrated significant differences for all variables. The results of this study demonstrated that a physical therapy home exercise program that emphasizes weight bearing and postural stability can improve self-perceived function, muscle strength, and postural stability in patients who are 4 to 12 months post-THA.