Superficial Flexor Tendonitis in a Horse

A 12 year old mare presented for sudden onset forelimb lameness and swelling of the tendons in the right front limb. On palpation, the swollen tendons were significantly sensitive to palpation yet it was not possible to determine if it was the superficial flexor tendon (SDF) or the deep digital flexor (DDF) tendon. The mare was a grade 3/5 lame in the right front when trotted in a straight line on firm ground. Ultrasound exam of the soft tissue structures revealed a core-like lesion within the outside corner of the SDF tendon. In Figures 1-3, the core-like lesion appears as a black area (red circle) within the body of the SDF tendon (blue circle).  In Figure 2, the image to the right is a cross-sectional view of the tendon and the lesion is a small black circle within the body of the SDF tendon. In the image to the left in Figure 2, the tendon is in a longitudinal view and the lesion appears as a black streak through the body of the SDF tendon.This view is important because it highlights the over-all length of the lesion which in this case was 4-5cm long. The cross-sectional area measured in Figure 3 determined that the core-like lesion was approximately 20% of the entire cross-sectional area of the SDF tendon.

Figure 1

Figure 2

The mare was treated with ultrasound guided injection of Platelet rich plasma (PRP), stall rest, daily ice therapy and we will follow-up with 3 doses of extra-corporeal shock wave treatment. We anticipate a full return to work after the appropriate period of rehabilitation.