Knotless Anchors in Acetabular Labral Repair: A Biomechanical Comparison

Surgeon-Specific Traction Time During Hip Arthroscopy for Primary Labral Repair Can Continue to Decrease After a Substantial Number of Surgeries

PURPOSE

The purpose of this study was to evaluate the total traction time and traction time as a function of anchors placed (TTAP) for primary labral repair in patients undergoing hip arthroscopy by a single surgeon.

METHODS

Patients were included if they received a primary labral repair with or without acetabuloplasty, chondroplasty, or ligamentum teres debridement as part of the treatment for femoroacetabular impingement (FAI). Patients were excluded if they had a previous ipsilateral hip surgery, prior hip conditions, Tönnis grade >1, open procedures, microfracture, ligamentum teres reconstruction, or labral reconstruction. TTAP was calculated by dividing total traction time by the number of anchors placed.

RESULTS

2,350 hips met the inclusion criteria. The mean age and BMI in this cohort were 34.22 years and 25.72 kg/m², respectively. A total traction time of 60 minutes was first achieved after 268 cases. Mean overall total traction time was 58.16 minutes (95% CI [57.35, 58.97]) and mean TTAP was 16.24 minutes (95% CI [15.93,16.55]) after 2,350 cases. Total traction time plateaued after 374 cases at 55.92 minutes, while TTAP plateaued after 487 cases at 14.93 minutes.

CONCLUSION

Surgeons who introduce hip arthroscopy into their practice can expect to see improvements in traction time during the first 500 surgeries performed, as total traction time plateaued after 374 cases and TTAP plateaued after 487 cases.

LEVEL OF EVIDENCE

IV: case series.

Prospective Analysis of Arthroscopic Hip Anatomic Labral Repair Utilizing Knotless Suture Anchor Technology: The Controlled-Tension Anatomic Technique at Minimum 2-Year Follow-up

BACKGROUND

Labral tears are the most common abnormalities in patients undergoing hip arthroscopic surgery. Appropriate management is crucial, as it has been shown that better overall outcomes can be achieved with labral restoration.

PURPOSE

To report the patient-reported outcomes (PROs) at minimum 2-year follow-up of patients who underwent hip arthroscopic surgery for labral tear repair using the knotless controlled-tension anatomic technique in the setting of femoroacetabular impingement syndrome (FAIS).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Data were prospectively collected for patients who underwent hip arthroscopic surgery for FAIS for labral tear repair using the knotless controlled-tension anatomic technique. Patients were excluded if they had prior hip conditions, prior ipsilateral surgery, Tönnis grade >1, a lateral center-edge angle (LCEA) <25°, or workers' compensation claims. Preoperative and postoperative scores at minimum 2-year follow-up were recorded for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sport-Specific Subscale (HOS-SSS), International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain. The proportion of patients who achieved the minimal clinically important difference (MCID) or patient acceptable symptomatic state (PASS) for the mHHS, HOS-SSS, and iHOT-12 were also reported.

RESULTS

A total of 309 hips were included. The mean patient age was 36.2 years (range, 12.8-75.9 years). The mean preoperative LCEA and alpha angle were 31.9° and 57.1°, respectively. A significant improvement on the mHHS (62.6 ± 15.7 preoperatively vs 86.9 ± 16.2 at 2-year follow-up), NAHS (63.1 ± 16.7 vs 86.1 ± 16.7), and HOS-SSS (39.8 ± 22.0 vs 74.2 ± 27.3) was found (P < .001 for all). A significant decrease was shown for VAS scores (P < .001). Also, 78.6% and 82.2% of patients achieved the MCID and PASS for the mHHS, respectively; 60.8% and 69.9% of patients met the MCID and PASS for the HOS-SSS, respectively; and the MCID for the iHOT-12 was met by 77.3% of patients.

CONCLUSION

In the setting of FAIS and labral tears, patients who underwent hip arthroscopic surgery for labral tear repair using the knotless controlled-tension anatomic technique demonstrated significant improvement in several validated PRO measures, the VAS pain score, and patient satisfaction at a minimum 2 years of follow-up. Based on this evidence, labral tear repair using the knotless controlled-tension anatomic technique seems to be a safe option.

Biomechanical comparison of knotless vs. knotted suture anchors in the acetabular rim with respect to bone density

BACKGROUND

Acetabular labral tears are managed with suture anchors providing good clinical outcomes. Knotless anchors are easier to use and have a quicker insertion time compared to knotted anchors. The purpose of this study was to compare the biomechanical behavior of two different anchor designs (knotted vs. knotless) in ultimate load testing in correlation with bone density in the acetabular rim.

METHODS

Eighteen knotted Bio-FASTak and seventeen knotless PushLock anchors (both: Arthrex Inc., Naples, FL, USA) were inserted in the rims of two human acetabula, with known bone density distribution. The anchors were subjected to load-to-failure tests. Anchors were additionally tested in solid polyurethane foam with defined densities.

FINDINGS

The Bio-FASTak group showed higher survival rates at 1, 2, and 3 mm displacement and was able to withstand significantly higher loads at 3 mm displacement (p = 0.031). There was no statistically significant difference in stiffness (p = 0.087), yield- (p = 0.190), and ultimate load (p = 0.222) between the two groups. Only the PushLock group showed correlation between bone volume over total volume (BV/TV) and stiffness (R = 0.750, p = 0.086) and between BV/TV and yield load (R = 0.838, p = 0.037). Experiments on solid polyurethane foam confirmed the correlation between the mechanical properties and tissue density for the same anchor.

INTERPRETATION

PushLock shows similar biomechanical properties to the Bio-FASTak, but eliminates knot tying and potentially abrasive knots. In addition, biomechanical properties of the PushLock are governed by local bone density.

Editorial Commentary: Acetabular Labral Repair-Is A Knotless Anchor Better?

Knotless anchors have an important role in arthroscopic acetabular labral repair. Different anchors show 2 primary failure modes: suture breakage and suture pullout from the anchor ("eyelet failure"). Knotless anchors show minimal displacement at physiological loads and should perform well for arthroscopic labral repair. Surgeons should consider the suture-passing device size and use a device that creates as small of a labral hole as possible.