Background: It is currently unknown whether functional restrictions
following total hip arthroplasty can reduce the prevalence of early
postoperative dislocation. Our hypothesis was that dislocation was more likely
to occur in patients who were not placed on these restrictions.
Methods: We performed a prospective, randomized study to evaluate
the role of postoperative functional restrictions on the prevalence of
dislocation following uncemented total hip arthroplasty through an
anterolateral approach. Of the 630 eligible consecutive patients, 265 patients
(303 hips) consented to be randomized into one of two groups (the
"restricted" group or the "unrestricted" group). The
patients in both groups were asked to limit the range of motion of the hip to
<90° of flexion and 45° of external and internal rotation and to
avoid adduction for the first six weeks after the procedure. The patients in
the restricted group were instructed to comply with additional hip precautions
during the first six weeks postoperatively. Specifically, these patients were
managed with the placement of an abduction pillow in the operating room before
bed transfer and used pillows to maintain abduction while in bed; used
elevated toilet seats and elevated chairs in the hospital, in the
rehabilitation facility, and at home; and were prevented from sleeping on the
side, from driving, and from being a passenger in an automobile. All patients
were followed for a minimum of six months postoperatively.
Results: There was one dislocation in the entire cohort (prevalence,
0.33%). This dislocation occurred in a patient in the restricted group during
transfer from the operating table to a bed with an abduction pillow in place.
Patients in the unrestricted group were found to return to side-sleeping
sooner (p < 0.001), to ride in automobiles more often (p < 0.026), to
drive automobiles more often (p < 0.001), to return to work sooner (p <
0.001), and to have a higher level of satisfaction with the pace of their
recovery (p < 0.001) than those in the restricted group. There was an
additional expenditure of approximately $655 per patient in the restricted
Conclusions: Total hip arthroplasty through an anterolateral
approach is likely to be associated with a low dislocation rate. Removal of
several restrictions did not increase the prevalence of dislocation following
primary hip arthroplasty at our institution. However, it did promote
substantially lower costs and was associated with a higher level of patient
satisfaction as patients achieved a faster return to daily functions in the
early postoperative period.
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.