Objective
To compare the axial biomechanical properties of intracondylar humeral osteotomies fixed with 4.5 mm transcondylar positional or cortical lag screws.
Study design
Ex vivo study.
Sample population
Paired humeri from 21 canine cadavers.
Materials and methods
An intracondylar osteotomy was created on each humerus to mimic an intracondylar fissure. Paired humeri were randomly assigned to fixation with a positional or a lag screw. All specimens were radiographed postinstrumentation to document proper screw placement. Axial load was applied to the distal articular surface of the trochlea at a rate of 1 mm/s until a 40% decrease in load was measured. Specimens were assessed for mode of failure with visual inspection and radiographs.
Results
Stiffness (1236.7 ± 181 N/mm vs. 1050.8 ± 265 N/mm), yield load (3284.3 ± 1703 N vs. 2071.1 ± 740 N), and maximum load (7378.0 ± 1288 vs. 5793.7 ± 2373 N) were greater in constructs fixed with a positional rather than a lag screw (p = .0008, .044, and .040, respectively).
Conclusion
In our model, mechanical properties were improved when the transcondylar osteotomy was stabilized with a 4.5 mm positional screw rather than a lag screw.
Clinical significance
This ex vivo study suggests that a transcondylar lag screw and positional screw are not biomechanically equal. Additional in vivo studies are need to help with clinical decision making when prophylactically treating HIF.
Development of postattenuation neurological signs (PANS) is a potentially severe complication after surgical attenuation of congenital portosystemic shunts in cats. This review summarizes findings of 15 publications that report occurrence of PANS in cats. PANS includes seizures but also milder neurologic
ObjectiveTo describe arthroscopic‐assisted hip toggle stabilization (AA‐HTS) in cats, evaluate its feasibility and associated rate of iatrogenic injury, and assess deviations from planned surgical technique.Study designEx vivo study.AnimalsSkeletally mature cat cadavers (n = 7).MethodsPreoperative pelvic computed tomography (CT) was performed for surgical planning and to identify the ideal femoral bone tunnel projection. Ultrasound‐guided transection of ligament of head of femur was performed. Following exploratory arthroscopy, AA‐HTS was performed using a commercially available aiming device. Surgical time, intraoperative complications, and feasibility of technique were recorded. Iatrogenic injury and technique deviations were assessed by postoperative CT and gross dissection.ResultsDiagnostic arthroscopy and AA‐HTS were successfully performed in all 14 joints. Median (range) surgical time was 46.5 (29‐144) min, including 7 (3‐12) min for diagnostic arthroscopy and 40 (26‐134) min for AA‐HTS. Intraoperative complications occurred in 5 hips, related to bone tunnel creation (4) and toggle dislodgment (1). Toggle passage through the femoral tunnel was the most challenging component of technique, recorded as mildly difficult in 6 joints. No damage to periarticular/intrapelvic structures was identified. Minor articular cartilage damage (<10% total cartilage area) was identified in 10 joints. Thirteen deviations (8 major, 5 minor) in surgical technique from preoperative planning were identified in 7 joints.ConclusionIn feline cadavers AA‐HTS was feasible but was associated with a high rate of minor cartilage injury, intraoperative complications, and technique deviations.Clinical significanceHip toggle stabilization using an arthroscopic‐assisted approach may be an effective technique for management of coxofemoral luxation in cats.
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