The effect of the sagittal ridge angle on cartilage stress in the equine metacarpo-phalangeal (fetlock) joint

作者：Liley Helen; Davies Helen; Firth Elwyn; Besier Thor; Fernandez Justin^*

来源：Computer Methods in Biomechanics and Biomedical Engineering, 2017, 20(10): 1140-1149.

DOI：10.1080/10255842.2017.1339795

• Equine fetlock fracture
• fetlock sagittal ridge
• fetlock cartilage stress

Fatigue failure of bones of the metacarpo-phalangeal (fetlock, MCP) joint is common in thoroughbred racehorses. Stresses within the fetlock joint cartilages are affected by the morphology of the third metacarpal bone (MC3) and proximal phalangeal bone, and the steepness of the median sagittal ridge of MC3 is believed to be associated with fracture. This study investigated the influence of the steepness of the sagittal ridge on cartilage stress distribution using a finite element model of the joint. Changes to the steepness of the sagittal ridge were made by applying a parabolic function to the mesh, creating four different models with sagittal ridge angles ranging from 95 degrees to 105 degrees. In the fetlock joint of Thoroughbred racehorses, sagittal ridge angles of>100 degrees were associated with higher Von Mises stresses in cartilage at the palmar aspect of the condylar groove than such stresses in joints with sagittal ridge angles of<100 degrees. Stresses were high in the specific region where fractures are known to originate in MC3. This aspect of morphology of the fetlock joint thus appears to play an important role in the magnitude and distribution of cartilage stresses, which, when acting on the underlying hard tissues of the articular calcified cartilage and subchondral bone may play a role in the initiation of fatigue fracture in the third metacarpal bone.

• 出版日期2017