There is an uncommon type of shoulder lameness in horses that produces a dropped elbow and flexing of the carpus (knee) and pastern at rest. At work, affected horses are typically severely lame with a significantly decreased forward phase of the stride. Radiographs of the shoulder in these cases usually reveal a combination of biceps tendonitis, bursitis, and inflammation of the bone (osteitis) in the area of attachment of the biceps tendon. This type of shoulder lameness does not usually respond to medical therapy and can become chronic, ending a horse’s athletic career. Recently, a Purdue University study was published that profiled three horses diagnosed with this type of shoulder lameness which were treated by surgically severing the biceps tendon.

None of the three horses had responded to conservative medical therapy and had been lame for several weeks. Radiographs revealed the typical combination of tendonitis, bursitis, and osteitis. At surgery, one horse had a tenotomy performed, where the biceps tendon was completely severed. The other two horses had five to six inches of the tendon removed (tenectomy). Remarkably, all three horses were sound immediately after surgery, which supports the theory that this unusual shoulder lameness is the result of excessive tension in the biceps tendon. Two of the horses in the study returned to an athletic career after several months of rest, and the third returned as a sound broodmare. The authors noted that horses with bicipital tendonitis (inflammation which involves the tendon to the biceps muscle) or bursitis (inflammation of a bursa) alone should not have this procedure performed because they will typically respond well to medical therapy.

Furgaro, M.N.; Adams, S.B. Journal of the American Veterinary Medical Association, 220(10), 1508-1511, 2002