The Science Behind Rehab Therapy
Photo: Anne M. Eberhardt/The Horse
In human medicine physical therapy (PT) is a well-established health care area. Likely because of physical therapists' success in treating people, veterinarians and equine professionals have been using PT to help manage a variety of medical conditions, from bone and soft tissue injuries to weakness and inflexibility.
According to Jennifer Brooks, PT, Med, CERTP, owner and operator of Equine Rehabilitation Services LLP, in Brookline, N.H., some of these conditions include, specifically:
- Muscle injury/damage following trauma or surgery;
- Tendon injuries (acute and chronic);
- Bucked shins, splints, curbs, and some fractures, such as otherwise "untreatable" pelvic fractures;
- Spinal dysfunction and back pain (described further in this article);
- Injuries or paralysis of the suprascapular nerve, which innervates (supplies nerves to) some of the shoulder muscles;
- Muscle atrophy (decrease in size/muscle wasting);
- Acute and chronic wounds (e.g., post-surgical healing sites);
- Neck, truck, and limb inflexibility;
- Stifle weakness and dysfunction (e.g., intermittent upward fixation of the patella);
- Recovery from neurologic disease such as equine protozoal myeloencephalitis (EPM) or equine motor neuron disease;
- Disuse contractures or atrophy during stall rest or immobilization; and even
- Loss of performance.
Although many enthusiastic owners, trainers, and veterinarians support using PT in horses, some members of the equine industry remain wary. The "science" behind PT in equine medicine is as inconsistent and unclear as it is with other complementary and alternative therapies, such as nutritional supplements and acupuncture (discussed in the August and October issues, respectively). For that reason PT has not been fully integrated into the care and husbandry of horses, despite the large number of medical and surgical conditions that equine physical therapists and rehabilitation professionals suggest are amenable to PT. Part of the problem associated with proving PT's worth is this wide range of treatable conditions, the number of different therapy methods, a lack of research dollars to conduct studies, and the small number of horses in each study.
What is Physical Therapy?
Physical therapy refers to the use of one or more physical approaches to promote and maintain the body's well-being, to help a horse recover from injury, and to re-educate an injured body part to move or function normally. Also referred to as rehabilitation, PT can include the use of various modalities such as heat and cold, hydrotherapy, therapeutic (not diagnostic) ultrasound, cold laser, and electrotherapy. First and foremost, however, a veterinarian should make an initial diagnosis of the problem before proceeding with any of these therapies.
According to veterinarians and other professionals to apply PT modalities:
Hydrotherapy involves applying water to an injured area to encourage healing. Cold hosing an injury to reduce inflammation is one of the simplest (and most beneficial) forms of hydrotherapy.
Cold therapy, similarly, helps reduce swelling in a recent injury and might be accomplished by pressing or wrapping ice packs around an affected area.
Heat therapy, on the other hand, causes blood vessels to dilate, increasing blood flow to the injured site to maximize healing. This therapy is used after pain and swelling/heat subside via cold hosing, hot compress, or a soaking boot (for lower limb injuries), among other approaches.
Therapeutic ultrasound involves using high-frequency sound waves to raise the temperature of selected deep tissues without heating the horse's skin. Properly trained veterinarians and therapists might use ultrasound to treat musculoskeletal injuries and promote wound healing.
Laser therapy employs infrared wavelengths to stimulate normal cell activity that has been disrupted by injury. This method is most commonly used to treat injuries and joint pain and to repair wounds. As with other therapeutic modalities, laser therapy should only be administered by a skilled veterinarian or therapist.
Electrotherapy is the application of an electric current via surface electrodes to produce controlled movement of the skin, muscle, tendon, and associated ligaments. Sheila Schils, PhD (biomechanics/kinesiology), a private equine rehabilitator in Wisconsin, reviewed the use of electrotherapy devices in horses at the 2009 American Association of Equine Practitioners (AAEP) annual convention. She says there are two main types of electrotherapy devices: sensory nerve or motor nerve stimulators (see TheHorse.com/19048 for a detailed rundown of these devices).
Despite the widespread availability and use of rehabilitation modalities such as electrical stimulators, machines alone cannot replace a rehabilitation specialist's own hands, skill sets, and problem-solving abilities. Schils says these devices can be an important part of the overall PT program, but professionals must use such equipment along with movement evaluations and exercises; this will improve the horse's biomechanics and re-educate muscle memory, which will help heal the current injury as well as assist in preventing reinjury.
"Machine therapy on its own is far from satisfactory, and if it is possible to incorporate a rehabilitation program at the same time as the use of machines, the result will be far superior to the 'machine only' cases," concurs Mary Bromiley, FCSP, SRP, RPT, a veterinary physiotherapist in England, in her 2000 AAEP convention abstract that reviewed these rehabilitation techniques.
Controlled physical activities, such as using a treadmill, underwater treadmill, and/or mechanical walker, schooling (in hand or under saddle), and swimming, for example, are also widely employed. These, along with manual techniques such as massage, stretching, and core stability training, are often employed in the successful rehabilitation of an injured or post-surgical horse, to assist performance horses during competition, and even aid mares during the postpartum period.
"Physical therapy should not be assumed to bring the horse back to pre-injury status, but should be viewed as a means to help heal the injury or surgery to the best possible outcome," Schils adds. Further, once a condition has become chronic, it will be more time-consuming and challenging to return to the horse to his previous level of performance.
Does PT Work?
Currently, there is a notable lack of clinical trials assessing the efficacy or safety of machines and/or other techniques equine physical therapists use. Most of the information on PT is extrapolated from human medicine, and few researchers have conducted equine-specific clinical trials demonstrating PT's efficacy.
In an attempt to provide a scientific ¬basis for using physical therapy and rehabilitation in the equine industry, Hilary Clayton, BVMs, PhD, Dipl. ACVSMR, MRCVS, the Mary Anne McPhail Dressage Chair in Equine Sports Medicine at Michigan State University's College of Veterinary Medicine, has focused on conducting evidence-based studies that measure the effects of certain physiotherapeutic techniques in horses. Clayton, who is also vice president of the American College of Veterinary Sports Medicine and Rehabilitation, recruited Australian equine physical therapist Narelle Stubbs, BAppSc (Phty), MAnimST (Animal Physiotherapy), to join her research team. Their first study results were published recently in the Equine Veterinary Journal and the American Journal of Veterinary Research.
"Much of this research is based on proprioceptive (unconscious perception of movement or position of the body) stimulation and responses," explains Clayton. "Stimulation of receptors in the skin results in activation of specific muscles that change the horse's movement pattern. With practice, these changes can become permanent and persistent after the skin stimulation ceases."
A key component of their research is to determine what type of skin stimulation produces the desired muscular response to overcome each horse's movement deficit. For example, one approach is to use lightweight bracelets that brush gently against the skin of the pastern and coronet as the hoof moves.
Higher on the horse's body, Clayton and colleagues are studying the effects of core training exercises on the horse's neck and back. Clayton's research has shown that performing baited stretches ("carrot stretches") regularly over a three-month period can activate and strengthen the muscles that support and stabilize the horse's back. These study results were published in the Equine Veterinary Journal in November 2010 and September 2011.
Kevin Haussler, DVM, DC, PhD, from the Orthopaedic Research Center at Colorado State University, is also making impressive headway in this field. Recently, Haussler and colleagues described their assessment of spinal manipulative therapy (chiropractic) and concluded that it can improve spinal flexibility in actively ridden horses.
The inclusion of rehabilitation discussions at some of the largest equine conferences in 2011 indicates that the discussion of PT is gaining importance. For example, Schils presented information on early mobilization, or controlled movement/exercise, for acute and chronic injuries at the Florida Association of Equine Practitioners conference, held in October. Based on her comprehensive review of the human and equine literature, Schils relayed that controlled early mobilization, within days of an injury or surgery, is beneficial and that immobilization is detrimental to the healing process.
These research studies and presentations show that physical therapy techniques appear to have potential in treating equine patients, just as they have come to be recognized as standard and effective modalities in human patients. But adoption of these modalities to the extent reached in human medicine "can only occur if the varied therapies are administered by a qualified person, correctly trained in the use of therapy apparatus, and who also possesses an in-depth knowledge of the physical demands of the individual equine disciplines," says Bromiley. "Physical therapy should not be considered a 'cure all.' "
For rehabilitation to be successful in horses, it "should not just rest on the shoulders of the specialist; it should involve the veterinarian, farrier, trainer, owner, barn manager, feed specialist, and saddle fitter, just to name a few," says Schils. "The key is putting all of our heads together to come up with an excellent rehabilitation plan."
About the Author
Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.