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

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 Study METHODS: 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.

Ex vivo mechanical properties of a 2.5-mm bone anchor for treatment of cranial cruciate ligament rupture in toy breed dogs.

OBJECTIVE: To determine the mechanical pull-out properties of a 2.5-mm bone anchor implanted in ex vivo femurs of toy breed dogs and to determine whether there is a difference between knotted and knotless configurations. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Eight paired harvested femurs. METHODS: Femurs were assigned to knotted or knotless configuration. Equal numbers of right and left femurs were tested. The caudolateral femoral condyle at the distal pole of the lateral fabella (F2 site) was drilled. The assigned configuration with braided suture combined with the bone anchor was implanted into the F2 site. Each configuration was positioned into a mechanical testing machine to measure yield load, load at 3-mm displacement, ultimate load, stiffness, and mode of failure at the beginning of the canine standing phase angle (150°). RESULTS: Mean ultimate load was 100.14 and 88.69 N (P = .798), mean yield load was 59.72 and 55.85 N (P = .708), load at 3-mm displacement was 46.72 and 43.33 N (P = .656), and stiffness was calculated to be 43.06 and 47.09 N/mm (P = .548) for knotted and knotless configurations, respectively. Mode of failure occurred primarily by anchor pull-out. CONCLUSION: The bone anchor withstood deformation at the estimated forces applied on the native cranial cruciate ligament (CCL) of toy breed dogs in both configurations. CLINICAL SIGNIFICANCE: This bone anchor may constitute a useful alternative for stabilization of the CCL deficient stifle in toy breed dogs. However, before it can be recommended for widespread use in dogs, closely monitored clinical trials must be conducted to assess outcome and complications associated with this implant.