Knotless Versus Knotted Suture Anchors for Labral Repair of the Hip: A Systematic Review of Clinical and Biomechanical Outcomes

Background: Arthroscopic labral repair of the hip is successfully performed with increasing frequency using either knotless or knotted suture anchors, each with its own risks and benefits.

Purpose: To examine biomechanical and clinical outcomes for labral repair of the hip based on the use of knotted or knotless suture anchors.

Study design: Systematic review; Level of evidence, 4.

Methods: A search was performed to retrieve clinical and biomechanical studies examining the use of knotless or knotted suture anchors for arthroscopic labral repair of the hip. The studied outcomes included functional outcome scores such as modified Harris Hip Score (mHHS) and Hip Outcome Score Activities of Daily Living, biomechanical outcomes, failure mechanisms, and complications such as revision/reoperation and conversion to total hip arthroplasty (THA).

Results: A total of 47 articles met inclusion criteria for analysis (5 articles examining biomechanical outcomes and 42 reporting clinical outcomes). Included patients (N = 6185) who underwent hip labral repair had a mean age of 33.0 ± 8.5 years and follow-up time of 43.8 ± 18.4 months. The knotless group (n = 2719) had a mean preoperative mHHS of 63.3 ± 4.1 and postoperative mHHS of 86.3 ± 2.8 at a mean follow-up time of 47.2 ± 16.1 months. The knotted group (n = 2600) had a mean preoperative mHHS of 69.5 ± 8.3 and postoperative mHHS of 88.8 ± 5.5 with a mean follow-up time of 44.8 ± 18.1 months. The most common reason for failure of knotless anchors in biomechanical studies was suture breakage or pullout, and for knotted anchors it was anchor pullout. Of the articles reporting on revisions and/or conversion to THA after labral repair, the knotless group had 225 reoperations (8.1%) and 123 cases of conversion to THA (4.4%). The knotted group had 101 reoperations (6.2%) and 31 cases of conversion to THA (1.9%).

Conclusion: Arthroscopic management of labral repairs of the hip using either knotless or knotted suture anchors appears to be both safe and effective in reducing pain and improving function. Biomechanical evaluation suggests differing failure mechanisms in knotted versus knotless anchors. The rates of revision and conversion to THA are low overall, irrespective of knotted or knotless anchors.