For decades, after a total hip arthroplasty (THA), orthopedic surgeons have handed patients a list of commandments worthy of Mount Sinai:
- Thou shalt not flex beyond 90°.
- Thou shalt not cross thy legs.
- Thou shalt not internally rotate.
- Thou shalt sleep with a pillow fortress.
All in the name of avoiding the dreaded early dislocation — the most common cause of early revision after THA. But what if you’ve been over-policing hips?
A large multicenter before-and-after study by Klaassen and colleagues from the Santeon Hip Osteoarthritis Group examined a simple but provocative question: Do minimal movement restrictions actually increase early dislocations?
The Study: 10,357 Hips Under Surveillance
This retrospective, multicenter before-and-after study included 10,357 patients undergoing THA between 2015 and 2020.
Two eras. Two philosophies:
- Strict Restriction Era (n = 7,666)
Classic precautions: no deep flexion, no crossing legs, careful transfers, and likely a few anxious family members serving as unofficial compliance officers. - Minimal Restriction Era (n = 2,691)
Fewer movement limitations. More normal life. Less fear of tying shoes.
The primary outcome? Dislocation within 90 days.
The Results: No Disaster
Dislocations in the “strict group” were 112 of 7,661 hips for a 1.46% dislocation rate. Dislocations in the minimal restriction group were 52 of 2,691 hips for a 1.93% dislocation rate. p = 0.093
No statistically significant difference. Early dislocation rate remained low in both groups.
What This Really Means
This study suggests that loosening movement restrictions after THA does not meaningfully increase early instability. And that has implications for patient comfort (dressing. toileting, sleeping, and basic human dignity).
It also means a faster return to normal life. Specifically, more natural movement patterns, less fear-avoidance and earlier functional independence.
Hip precautions have long been dogma. But dogma deserves data. This study adds to a growing body of evidence suggesting that for many patients — particularly with modern implants and surgical techniques — strict precautions may be more tradition than necessity.
The Nuance
Before you burn the precaution handouts, some points to keep in mind about the study. This was uncontrolled and retrospective. It doesn’t eliminate the importance of component positioning, soft-tissue tensioning, and patient selection. And high-risk patients (neuromuscular disease, revision cases, noncompliance concerns) may still warrant tailored precautions.
But for routine primary THA? This study nudges us toward a more liberal approach.
The Big Question
Perhaps the era of the “hip police” is ending. Perhaps modern implants, surgical techniques, and patient education have done more to prevent instability than sleeping with an abduction pillow ever did.
One thing’s clear: If minimal restrictions don’t increase dislocations, you may be able to give your patients something radical after THA — an increased measure of freedom.
Origin Study Title: Minimal Movement Restrictions Do Not Increase Hip Dislocations Following Total Hip Arthroplasty
Authors: Amanda D. Klaassen, MSc; Nienke W. Willigenburg, Ph.D.; Jan Willem Q. Musters, M.D.; Jelmer Jager, MSc; Rudolf W. Poolman, M.D., Ph.D.; the Santeon Hip Osteoarthritis Group