Summary
Fracture of the proximal sesamoid bones is a common injury of racing horses, usually
resulting from over-dorsiflexion of the metacarpophalangeal joint. The purpose of
this study was to develop a computer-aided method utilizing stereo-radiography, computed
tomography, and finite element method to determine three-dimensional stress distribution
in the proximal sesamoid bones during metacarpophalangeal joint dorsiflexion. The
stress pattern was characterized by a compressive component on the articular part
of the bone and a tensile component on the non-articular part of the bone. Maximum
principal stresses were 2.5, 9.1 and 15.5 MPa and minimum principal stresses were
-1.9, -9. 2 and -14. 9 MPa for metacarpophalangeal joint angles of 140°, 125° and
110°, respectively. The distal portion of the articular part of the bone experienced
the largest compressive stress. In this study changes in the orientation and magnitude
of the ligament force vectors did not significantly change stress patterns of the
proximal sesamoid bone.
This study was designed to determine stress patterns of the proximal sesamoid bones
in horses. Stress patterns were determined by finite element method analysis. Compressive
stresses were present on the articular side, and tensile stresses were present on
the nonarticular side of the bones. The magnitude of load applied to the bone did
not appreciably change the pattern of stresses.
Keywords
Sesamoid bones - equine orthopaedic disease - equine leg
