Feasibility and safety of arthroscopic medial glenohumeral ligament and subscapularis tendon repair with knotless anchors: A cadaveric study in dogs

OBJECTIVE: To test the feasibility and safety of an arthroscopic imbrication of the medial glenohumeral ligament (MGHL) and the subscapularis tendon with knotless anchors in dogs. STUDY DESIGN: Cadaveric study. SAMPLE POPULATION: Ten limbs. METHODS: Cranial and caudal arms of the MGHL were imbricated with a 2.9- or a 2.4-mm knotless anchor. A horizontal mattress suture secured with a 3.5-mm knotless anchor was used to imbricate the subscapularis tendon. Computed tomography measurements included (1) the bone stock around the anchors, (2) the angle between the anchor and the joint surface (insertion angle), and (3) the angle formed by lines tangent to the cortices of the bones (safety angle). Limbs were dissected to assess the position of anchors. Safety and insertion angles and bone stock were compared among anchors with a Kruskal-Wallis test (P < .05). RESULTS: Surgical repairs were achieved in all limbs, with only 2 of 30 anchors incorrectly placed, both in the glenoid. The safety angle of the humeral anchor (HA; median, 89°) was greater than that of the cranial glenoid anchor (CrGA; P = .0017) and the caudal glenoid anchor (CdGA; P < .001). The insertion angle of the HA (median, 68°) was also greater than that of the other anchors (P < .001 and P = .001). The insertion angle of the CrGA (median, 26°) was greater (P = .0191) than that of the CdGA (median, 7°). All anchors were inserted at the MGHL and subscapularis footprint. CONCLUSION: Arthroscopic imbrication of MGHL and subscapularis tendon was feasible. HA were safer to place than glenoid anchors. CLINICAL SIGNIFICANCE: The results of this feasibility study justify further evaluation of the indications and outcomes of this technique in dogs with shoulder instability.