Osteomyelitis of the axial border of the proximal sesamoid bones in seven horses.

The study involves seven lame adult horses suffering from a condition known as osteomyelitis (bone infection) in the axial region of proximal sesamoid bones, as determined through radiography. The severity of lameness varied in the horses with an average duration of 5.6 months. The study also employed scintigraphy and computed tomography to further understand the bone destruction and the extent of lesions in the affected bones.

Subjects and Methods

• The study involved seven lame adult horses that were identified with destructive lesions in the sesamoid bones through radiography.
• The degree of lameness in these horses ranged from 2 to 5 (on a scale of 1 to 5) at the time of examination, with the problem having persisted anywhere from a few days to up to two years.
• Four of these horses underwent post mortem computed tomography to delve more into the extent of bone destruction.
• In addition, the technique of scintigraphy, which examines bone activity, was used on four of the five horses examined to inspect sesamoid bone activity.

Findings

• The radiographic examination discovered that the destructive lesions were primarily located at the level of the mid-body and the apical region of axial borders.
• The lesions varied – some were cystic in nature while others caused more extensive erosion of the axial border.
• Scintigraphy findings substantiated increased activity in the proximal sesamoid bones in the clinically lame limb of four of the horses.
• Computed tomography scans unveiled a more extensive bone destruction and cavitary lesions in the cancellous bone of the affected sesamoid bones than revealed by radiography.
• Two horses that did not exhibit clinical symptoms also showed signs of cavitary lesions not observed through radiography.
• This submits evidence of osteomyelitis in the axial region of the proximal sesamoid bones.
• Additionally, three horses exhibited septic synovitis of the flexor sheath on the lame limb, with two of these also suggesting septic arthritis in the fetlock joint.

Conclusions

• The study indicates the limitations of radiography in identifying cavitary lesions and the benefits of scintigraphy and computed tomography in providing a clearer view of bone destruction.
• The findings advocate early and thorough examination of horses for potential symptoms of osteomyelitis and related conditions, even when clinical symptoms are lacking.
• The conditions of the affected horses suggest a severe trajectory for osteomyelitis in septic synovitis and septic arthritis if not treated promptly and effectively.