Many horses struggle with stifle dysfunction due to injury, surgery, immobility, or disease. According to Jennifer H. Brooks, PT, MEd (Masters of Education), of Equine Rehabilitation Services, in Brookline, N.H., the stifle joint (comparable to a human’s knee) is the largest, most complex joint in the horse, and dysfunction left untreated can lead to additional joint degradation.

Brooks described her physical therapy approach for restoring strength and coordination to horses with intermittent upward fixation of the patella or other hind-limb weakness issues at the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas.

“Treatment of both intermittent upward fixation of the patella in horses and anterior knee pain in humans involves client education, increase in activity level, a stretching program, and an ascending therapeutic strengthening exercise progression,” she said. “A thorough veterinary examination should first clear the horse for physical therapy treatment referral. Horses recovering from injuries, surgery, or systemic diseases are appropriate for this program.”

Brooks said owners often report that affected horses are clumsy, frequently stumble, trip, get their hind legs stuck behind them, have a hind limb that gives out or collapses, and/or have an audible click or pop when shifting weight on or off of the involved leg(s). She also noted that affected horses tend to be overweight (body condition score 6 or higher on a scale of 1 to 9), have weak abdominal and/or topline muscles, generalized deconditioning, and atrophied (muscle wasting in) hind end muscles. The patellae (knee caps) might also visibly jump when the horse initiates a weight shift or steps forward