Re-evaluating Overhang Thresholds for Iliopsoas Impingement After Total Hip Arthroplasty
Total hip arthroplasty (THA), or a hip replacement, is a common and highly successful procedure. However, a small percentage of patients experience persistent pain in the front of the hip following surgery, known as iliopsoas impingement (IPI). Historically, the treatment for IPI relied on a specific measurement: an 8 mm threshold of anterior acetabular component (socket) overhang. If the overhang was less than 8 mm, less invasive iliopsoas lengthening or release was preferred. If the overhang was 8 mm or greater, a more extensive surgery to revise the acetabular component was typically recommended.
Our new study, however, challenges this 8-mm rule. We retrospectively reviewed 86 hips in patients who underwent an advanced, minimally invasive procedure called arthroscopic iliopsoas fractional lengthening (IPFL) for IPI. We compared the outcomes of patients with less than 8 mm of overhang to those with 8 mm or more.
The results were compelling:
Equal Pain Relief: We found no significant differences in postoperative pain scores, activity levels, or overall satisfaction between the two groups. Groin pain improved significantly for both.
Low Revision Rates: The rate of needing a subsequent surgery to revise the hip socket was low and not significantly different between the groups (1.5% for <8 mm vs. 5% for ≥8 mm).
The Bottom Line: Our findings suggest that the minimally invasive arthroscopic IPFL procedure can be a highly effective treatment for IPI, even for patients with a large degree of component overhang. This is a new direction in the treatment of IPI given that historically, these patients were treated with more invasive surgery as first-line treatment, namely revising their hip replacement with new components. Because IPFL is less invasive than an open revision surgery, it should be generally now be considered the first-line surgical option for patients whose IPI hasn't improved with nonoperative treatments like physical therapy and injections.
Check out the study for yourself:
At the Journal Website
On PubMed
