PUNCTURE WOUNDS INTO THE NAVICULAR BURSA OF THE HORSE

Radiography was used to evaluate 32 horses presented for puncture wounds into the navicular bursa. At the initial radiographic examination, 21 horses had no radiographic signs of osteomyelitis, while 11 did. The mean-time interval between injury and radiographic examination was 20.6 days for horses without evidence of osteomyelitis and 59.3 days for those with evidence of osteomyelitis. Radiographic signs of osteomyelitis of the navicular bone included flexor cortical destruction and irregularity of the flexor surface. Other abnormalities included pathologic fracture of the navicular bone, subluxation of the distal interphalangeal joint, or secondary joint disease. The lateromedial and palmaroproximal-palmarodistal oblique projections were most useful for identifying abnormalities of the navicular bone. There was a high correlation between horses that had positive presurgical radiographic signs and surgical findings. However, approximately 50% of horses that had negative radiographic findings initially had positive surgical findings. Ten of 21 horses with negative radiographic findings on initial examination had evidence of bony lesions when reevaluated from 3 weeks to 6 years later. Nine of 11 horses with radiographic signs of osteomyelitis on initial radiographic examination were euthanatized or had an unsatisfactory outcome. Seven of 10 horses with radiographic signs on reexamination were euthanatized. Thirteen of 20 horses with positive surgical findings for navicular bone infection were euthanatized or had an unsatisfactory outcome.