Effect of immediate full weight bearing on abductor repair and clinical function after THA through a modified Hardinge approach.

This study evaluated the effect of immediate full weight bearing on abductor repair and clinical function after total hip arthroplasty (THA) using a direct lateral (modified Hardinge) approach. The surgical approach detached a bone flake with the abductors, providing a radiographic marker for abductor displacement and healing. Patients in whom weight bearing was restricted for 6 weeks (partial-weight bearing group) were compared with patients who were immediately weight bearing (full-weight bearing group). A total of 307 patients (309 hips) were followed for a mean of 14 months (range, 12-36 months). The partial-weight bearing group (163 patients) underwent 6 weeks of partial weight bearing, and the full-weight bearing group (146 patients) underwent immediate full weight bearing. The abductor repair was assessed radiographically via the bone flake harvested with abductor muscles. Nonunion of the abductor bone was observed in 12 (7%) patients in the partial-weight bearing group and 9 (6%) patients in the full-weight bearing group (P=.55). Patients in the full-weight bearing group had significantly earlier discharge from hospital than the partial-weight bearing group (2.6 vs 3.5 months, respectively; P=.0021). Patients in the full-weight bearing group had a higher mean Engh score (6.58) radiographically than did patients in the partial-weight bearing group (4.92) (P=.0005). No difference was observed in Harris Hip Score, limp, thigh pain, high-grade heterotopic bone, trochanteric bursitis, or stem subsidence between groups. Restricting weight bearing postoperatively to protect the Hardinge abductor repair appears unnecessary, and recovery of activity is improved with immediate weight bearing.