Abstract
Background
The use of the direct anterior approach (DAA) for total hip arthroplasty (THA) has increased in recent years. This is in part due to the proposed benefits of a faster early recovery and a lower risk of dislocation. The purpose of this study is to understand the dislocation rate in a non-selective, consecutive cohort of patients undergoing THA via the DAA including those at high risk for instability due to spinopelvic pathology.
Methods
We performed a retrospective review of a large prospectively collected single institution database assessing all patients undergoing THA via the DAA between 2011 and 2017. The primary outcome measure was dislocation at minimum two-year follow-up. We then stratified patients by known risk factors for dislocation including spinopelvic pathology and performed an in-depth analysis of those patients who had a dislocation event.
Results
2,831 hips in 2205 patients were included in the study. Mean age was 64.9 (24–96) and 1,595 (56.3%) were female. Mean BMI was 29.2 (15.1–53.8). There were 11 dislocations within one year of the index operation (0.38%) and 13 total dislocations at terminal follow-up (0.45%). Five dislocations required revision (38.4% of dislocations 0.17% overall). When stratified by experience the dislocation rate for surgeons who had completed their learning curve was 0.15% compared to 1.11% in those who hadn't. There were 666 patients with an established diagnosis of spinopelvic pathology or prior surgical instrumentation, only 2 (0.30%) dislocated and neither required revision.
Conclusion
In a non-selective, consecutive cohort of patients undergoing THA via the DAA the risk of dislocation is low. Even amongst patients with lumbosacral stiffness secondary to spinal instrumentation or degenerative changes, the rate of dislocation is low following THA via the DAA. Our data suggests that utilizing the DAA in high risk patients may be protective against dislocation without the need for additional constraint or the use of newer bearing constructs that lack long term outcome studies. The inclusion of seven surgeons suggests that these results are generalizable.
