An investigation of the relationship between hindlimb lameness and saddle slip.

REASONS FOR PERFORMING STUDY We have observed saddle slip consistently to one side because of a crooked rider, an ill-fitting saddle, asymmetry in a horse's thoracolumbar shape and lameness. Currently, there are no objective data to permit assessment of the relative importance of each factor. OBJECTIVES To document the frequency of occurrence of saddle slip in horses with hindlimb lameness compared with other horses. To describe the effect of lameness characteristics and grade, the abolition of lameness by diagnostic analgesia, breed, size, thoracolumbar shape and symmetry and the rider's weight. METHODS One hundred and twenty-eight horses were assessed prospectively, and lameness and saddle slip were assigned a grade before and after diagnostic analgesia. The thoracolumbar shape and symmetry were measured objectively. In 3 horses, the force distribution and magnitude underneath the saddle were measured before and after diagnostic analgesia. RESULTS The saddle consistently slipped to one side in 38 of 71 horses (54%) with hindlimb lameness, compared with one of 26 horses (4%) with forelimb lameness, none of 20 (0%) with back pain and/or sacroiliac joint region pain and none of 11 sound horses (0%). The association between saddle slip and hindlimb lameness was significant (Spearman's rank correlation coefficient, ρ = 0.548, P<0.001). Diagnostic analgesia abolishing the hindlimb lameness eliminated the saddle slip in 37 of 38 horses (97%). In 2 horses, the saddle continued to slip after resolution of lameness; one horse had bilateral forelimb lameness and the other horse had concurrent hindlimb and forelimb lameness. The saddle of both these horses was asymmetrically flocked. The saddle slipped to the side of the lamer hindlimb in most horses (32 of 37 [86%]). No horse with saddle slip had significant left-right asymmetry of the back at 4 predetermined sites. CONCLUSIONS AND CLINICAL RELEVANCE Hindlimb lameness is an important factor in inducing saddle slip. Saddle slip may be an indicator of the presence of hindlimb lameness.