Circumferential Labral Reconstruction With Knotless All-Suture Anchors Restores Hip Distractive Stability: A
Ajay C Lall1, Benjamin L Smith2, Ady H Kahana-Rojkind3
1LALL Orthopedics Research Academy, Paramus, New Jersey, USA.
Background:
The essential component of managing femoroacetabular impingement involves restoration of the original labral function. Circumferential labral reconstruction (CLR) has shown positive results. However, biomechanical studies of CLR are limited and have not established the efficacy of the modern knotless all-suture anchor (ASA) pull-through technique.
Hypotheses:
(1) CLR with knotless ASA fixation will restore native labral suction seal biomechanics; (2) tensioning the ASA to a high-tension state will increase the peak distractive force.
Study Design:
Controlled laboratory study.
Methods:
Eight fresh-frozen human cadaveric hips were dissected free of all soft tissue except the native labrum and transverse acetabular ligament. On an electromechanical testing system, the hips were compressively loaded to 250 N to initiate a suction seal and distracted at a rate of 10 mm/s until rupture of the suction seal. Hips were tested in 4 states: intact labrum, full labral removal, knotless CLR with moderate anchor tension, and CLR with high anchor tension. Peak distractive force (in newtons) was compared using repeated measures analysis of variance (P < .05). Acetabular bevel angles (θ) were measured at labral clockface positions outside the transverse acetabular ligament using a 3-dimensional digitizer stylus after rim preparation. Linear regression plots compared θ and peak distractive force in the CLR state.
Results:
Peak force values were 138.5 ± 13.6 N (mean ± SE) for the intact labrum, 18.4 ± 2.79 N for labral excision, 95.4 ± 23.3 N for moderate-tension CLR, and 126.2 ± 27.3 N for high-tension CLR. Significant differences were observed only when full labral removal was compared with the other conditions: intact (P < .001), moderate-tension CLR (P = .016), and high-tension CLR (P = .002). Steeper acetabular bevel angles (smaller θ) were correlated with greater suction seal restoration (P < .05).
Conclusion:
CLR restored distractive stability on average to 82.0% of the intact value after labral deficiency. Retensioning did not significantly increase peak distractive forces.
Clinical Relevance:
These findings provide biomechanical validation supporting CLR using knotless ASAs in an effort to minimize volumetric bone loss and provide other surgical advantages. The prepared rim's bevel angle may be an important variable to optimize for improved suction seal restoration.
