Background:

Hip precautions are traditionally employed after posterior total hip arthroplasty (THA). The primary purpose was to investigate the necessity of hip precautions after posterior approach THA. We hypothesized that eliminating precautions in patients that achieved appropriate intraoperative stability would not increase the dislocation rate.

Methods:

Randomized controlled trial of 346 consecutive eligible patients undergoing primary THA with mean follow up of 2.3 years (range 11 months to 3.7 years).

Exclusion criteria:

lumbar fusion, scoliosis, abductor insufficiency, inability to achieve intraoperative stability with combined 90° flexion and 45° internal rotation in 0° adduction. Fisher’s exact test was used to compare dislocation rates between the hip precaution (HP) control group and no hip precaution (NP) study group. Mann-Whitney U test was used to compare differences in HOOS JR scores at 2,6,12 weeks between groups.

Results:

The dislocation rate was not increased in the NP (0/172: 0%) group compared to the HP group 4/174 (2.29%) (p=0.418). All dislocations occurred in the precautions group, two of which required revision. There was no difference in mean HOOS Jr. scores at any 2, 6, or 12 weeks (p>0.05 at all timepoints) (secondary outcome) CONCLUSION: Eliminating hip precautions in patients undergoing posterior approach THA that achieve 90°/45°/0° intraoperative stability does not increase the rate of dislocation. In fact, every dislocation occurred in patients receiving hip precautions. Short term patient reported outcome measures were not affected by hip precautions. Surgeons may discontinue the use of hip precautions as the standard of care in patients achieving 90°/45°/0° stability.