Muscular strength after total hip arthroplasty

BACKGROUND AND PURPOSE Minimizing the decrease in muscular strength after total hip arthroplasty (THA) might allow patients to recover faster. We evaluated muscular strength in patients who were operated on using 3 surgical approaches. PATIENTS AND METHODs: In a prospective cohort study, 60 patients scheduled for primary THA were allocated to the direct lateral, posterior, or anterior approach. Leg press and abduction strength were evaluated 2 weeks or less preoperatively, 2 and 8 days postoperatively, and at 6-week and 3-month follow-up. RESULTS Differences in maximal strength change were greatest after 2 and 8 days. The posterior and anterior approaches produced less decrease in muscular strength than the direct lateral approach. 6 weeks postoperatively, the posterior approach produced greater increase in muscular strength than the direct lateral approach, and resulted in a greater increase in abduction strength than the anterior approach. At 3-month follow-up, no statistically significant differences between the groups were found. The operated legs were 18% weaker in leg press and 15% weaker in abduction than the unoperated legs, and the results were similar between groups. INTERPRETATION The posterior and anterior approaches appeared to have the least negative effect on abduction and leg press muscular strength in the first postoperative week; the posterior approach had the least negative effect, even up to 6 weeks postoperatively. THA patients have reduced muscle strength in the operated leg (compared to the unoperated leg) 3 months after surgery.