In vitro mechanical properties and failure mode of the equine (pony) cranial cruciate ligament.
In vitro failure modes and mechanical properties of the equine cranial cruciate ligament (CCL) were evaluated in 15 stifle joints from 10 ponies. Ponies were from 3 to 25 years of age and weighed from 122 to 208 kg. Femur-CCL-tibia specimens were mounted in 48 degrees of flexion, distracted until a 500-g tensile preload was achieved, and then tested by tensile loading to failure. Specimens failed by complete midsubstance CCL rupture (n = 9), combined tibial insertion avulsion fracture and midsubstance CCL rupture (n = 4), and combined femoral origin avulsion fracture and midsubstance CCL rupture (n = 2). No significant differences were found between CCL mechanical properties and failure mode or body weight. Femur-CCL-tibia maximum tensile loads ranged from 1,945 to 4,326 N (median, 2,914 N). Mean maximum tensile load (N) per kilogram of body weight was 17.98 N/kg (median, 17.55 N/kg). These pony specimens had stiffer cranial cruciate ligaments (median, 320.2 N/mm) with a higher elastic modulus (median, 321.7 MPa) than has been reported for other species. Significant decreases in linear tensile load (P = .0292), maximum tensile load (P = .0493), and increases in strain to maximum load (P = .0463) were found in the specimens from 20- to 25-year-old ponies when compared with those from 3- to 10-year-old ponies.
Rich
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Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square.
Glisson
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D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000502:physiology; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005269:Femur; D006736:Horses / Q000293:injuries* / Q000502:physiology; D012044:Regression Analysis; D012421:Rupture / Q000662:veterinary; D013045:Species Specificity; D013977:Tibia