Ex vivo evaluation of arthroscopically assisted shoulder stabilization in dogs using an intra‐articular aiming device

Abstract

Objective: To evaluate the use of an intra-articular aiming device (IAD) for medial shoulder stabilization with a suture-toggle repair or an interference screw repair using bone anchors in dogs. Study design: Ex-vivo StudyMethods: Specimens were randomly divided into 2 groups (anchor and suture-toggle) with 10 shoulders each. Abduction angles were measured by goniometry prior to and following medial glenerohumeral ligament transection and after receiving arthroscopically assisted stabilization with either bone anchors or suture-toggle constructs. Bone stock and insertion angles were measured with computed tomography scans. All specimens were inspected by dissection.Results: Abduction angles increased post-transection in both groups, and were restored to normal in the anchor group, but 2 smaller than normal in the suture-toggle group following stabilization. Median magnitude of bone stock surrounding all tunnels ranged between 5.9 and 12.9 mm in the anchor group and 8.8 and 15.6 mm in the suture-toggle group (p = .002). Median insertion angles at the cranial glenoid, caudal glenoid, and humerus were 17.3 , 36.8 and 43.4 in the anchor group, respectively, and median insertion angles at the glenoid and humerus were 38.2 and 35.6 in the suture-toggle group, respectively (p = .91). Placement of anchors were not feasible in 3 specimens in the anchor group, and mild violations of the articular surfaces were detected in 3 specimens overall. Conclusion: Arthroscopically assisted shoulder stabilization with an IAD was feasible in canine cadavers.Clinical Significance: An IAD may facilitate arthroscopic shoulder stabilization in dogs. Further studies are warranted to evaluate safety and efficacy in a clinical setting. | INTRODUCTIONThe canine shoulder joint is highly mobile with an extensive range of motion. Its design reflects this. A relatively small glenoid is paired with the much larger humeral head to accommodate this range of motion and as a result has an inherent predisposition to instability. 1,2 A complex interaction between both passive and active stabilizers is required to maintain stability. The active stabilizers, such as subscapularis, supraspinatus,

Long-Term Clinical Outcome of Medial Shoulder Instability in a Dog Treated with Synthetic Implant, Cortical Button, and Interference Screw

“…This positioning seemed appropriate to preserve the integrity of the glenoid rim, especially in a small dog. The safety implantation of anchors has only been studied in dogs above 20 kg, 30 31 whereas sutures with buttons have been used for scapular fixation in small dogs under 10 kg. 7 15 The wide flat implant required broad tunnels, which could be a limitation for the safety of the implantation and a risk for glenoid integrity.…”

“…27 31 Indeed, reaching the optimal anchor insertion angle for the greatest pullout resistance (i.e., “deadman's angle”) is difficult yet essential to achieve satisfactory implantation and decrease the risks of loosening. 31…”

“…15,27,30,31 Suture toggles have been suggested to have biomechanical advantages over knotless anchors, owing to the difficulty to implant and angulate anchors. 27,31 Indeed, reaching the optimal anchor insertion angle for the greatest pullout resistance (i.e., "deadman's angle") is difficult yet essential to achieve satisfactory implantation and decrease the risks of loosening. 31 Medial implantation without a minimal lateral approach (as discussed in 7 ) could be advantageous.…”

“…27,31 Indeed, reaching the optimal anchor insertion angle for the greatest pullout resistance (i.e., "deadman's angle") is difficult yet essential to achieve satisfactory implantation and decrease the risks of loosening. 31 Medial implantation without a minimal lateral approach (as discussed in 7 ) could be advantageous. In theory, careful implantation without penetrating the overlying soft tissues should limit the risk of entrapping the suprascapular nerve with the button.…”

“…Using a cortical button avoided any concerns about the safety angle of the anchor or screw insertion and the associated risks of loosening. 15 27 30 31 Suture toggles have been suggested to have biomechanical advantages over knotless anchors, owing to the difficulty to implant and angulate anchors. 27 31 Indeed, reaching the optimal anchor insertion angle for the greatest pullout resistance (i.e., “deadman's angle”) is difficult yet essential to achieve satisfactory implantation and decrease the risks of loosening.…”