A study of 118 cases of navicular disease: radiological features

Dorsoproximal-palmarodistal oblique, lateromedial and palmaroproximal-palmarodistal oblique radiographic projections were used with standard techniques to examine 118 horses with clinical signs of navicular disease. All radiological features which have previously been reported as significant changes in the navicular bones of horses with navicular disease were recorded. Comparisons were made between these features in lame limbs and sound limbs in unilaterally lame horses and most lame limbs and least lame limbs in bilateral but asymmetrically lame animals. Their relationship to the degree of lameness was also analysed. No relationships were identified between the characteristics of distal border synovial invaginations, flattening and/or thinning of the flexor cortex and limb distribution or severity of lameness. Defects in the flexor cortex, proximal border remodelling, medullary trabecular disruption and medullary sclerosis appeared to be related to limb affliction and severity of lameness while proximal border enthesophytes, and poor flexor corticomedullary demarcation presented evidence of a relationship to the grade of lameness. Poor flexor corticomedullary demarcation and fragmentation of the distal border were related to the severity of lameness in bilateral but asymmetrically affected horses. The presence of peri-articular osteophytes and mineralisation of the flexor digitorum profundus were too infrequently recognised to permit meaningful data evaluation.