Proximal Adductor Avulsion: A Biomechanical Comparison of Suture Anchor Repair Techniques

OBJECTIVES: Acute avulsion of the proximal fibrocartilaginous origin of the adductor longus (AL) is an injury mostly occurring in individuals that perform cutting and rapid lateral movements such as in hockey, soccer, and rugby. Especially in competitive athletes, recent trends have advocated for surgical repair of these acute injuries. However, while multiple repair configurations have been proposed, the current literature lacks biomechanical data to guide surgical technique. Therefore, the purpose of this study was to determine load-to-failure values for two proximal adductor repair techniques and to compare their strength to that of a native, uninjured proximal adductor tendon. METHODS: Seventeen cadaveric fresh frozen pelvic specimens were dissected to preserve the proximal adductor tendon and the fibrocartilage attachment to the pubis. The specimens were then divided into three groups: an intact AL tendon(baseline control), and ‘torn’ tendons repaired with either a 2-suture anchor or 4-suture anchor technique. Once repaired, specimens were cyclically loaded on a custom jig to simulate a maximal effort soccer-style kick. Testing endpoints included suture anchor pull-out, loss of clamp fixation, or catastrophic tendon failure. To control for individual differences, values were reported both in terms of gross force and as load-to-displacement ratios. Following collection, data from each of the three groups were recorded and analyzed via Kruskal-Wallis and multiple comparison tests. RESULTS: The mean load to failure for the 4-anchor group was 83.74±19.28 N, which was significantly greater than for either the intact (25.43±3.46 N, p <0.05) or 2-anchor repair (20.58±1.33 N, p <0.001) conditions. All intact and 4-anchor repair specimens failed via disruption distal to the adductor’s musculotendinous junction, with no failure at the bone-anchor interface noted in either of these groups. In contrast, 80% of 2-anchor repairs failed at the bone to anchor interface. In this group, following initial pullout, failure of a secondary anchor occurred with 41.4% less force than for the index failure (p < 0.001). CONCLUSION: This study provides biomechanical data which identifies a 4-anchor repair as being much more resistant to surgical-site failure than a 2-anchor construct. Further, the 4-anchor group failed at the same anatomic location as the intact adductor group, suggesting that a 4-anchor construct results in a repair that acts similar to an uninjured control. Based on this finding, a 4-anchor repair construct should be preferentially used in proximal adductor repair whenever clinically feasible.