Equine physical therapy: Writing the exercise prescription

Equine physical therapy (PT) has been a subject generally avoided byveterinarians, and often delegated to para-professionals with varying degreesof training.

The lack of teaching in this field has caused it to become somethingof a "black box"-a treatment modality that we recognize as potentiallybeneficial, but that we brush over because of a lack of understanding.

No veterinarian would simply write a prescription for medication, withoutproviding the specific drug, dosage and frequency of administration.

Equine practitioners regularly prescribe pharmaceuticals, selected surgicalprocedures, nutritional supplements, even corrective shoeing, while PT remainsthe "last frontier."

Confusion

The large number of treatment modalities available - various massagetechniques, therapeutic ultrasound, hot and cold packs, electrostimulation- engenders confusion. These specific regimes should not be viewed as primarycomponents of therapy, but rather as ancillary aids; the "modalities"are to physical therapy what anti-inflammatory agents can be to surgery-whenused properly, they are beneficial. Scientific research is lacking in equinePT, and the prolific articles in lay journals seem sometimes to increasethe confusion.

Exercise prescription

PT's backbone is the exercise prescription. The prescription is basedon:

* Clinical diagnosis,

* A thorough understanding of the equine muscular system, and

* Performance requirements of the patient.

A better understanding of the principles of physical therapy is necessaryif the veterinarian is to appropriately advise the client and direct thepara-professionals attending the patient.

Understanding the muscular system

While muscular anatomy is relevant, it is more important for us to understandmuscle function. Muscle is a dynamic tissue, with every action-from blinkingan eye to performing a dressage test - involving the orchestrated contractionand relaxation of specific muscle groups. When this orchestration fails,injury occurs; when injury occurs, physical therapy is required to restorefull function.

Normal muscle function implies both strength and flexibility. A healthymuscle must be strong enough to perform without injury. Muscle weaknessis a consequence of athletic injury. Hence, restoration of strength mustbe a key component of any rehabilitation program.

Flexibility is defined as the ability of the muscle to relax ("letgo") and yield to passive stretch (like a rubber band). It is necessaryfor smooth agonist-antagonist activity. Lack thereof sets the stage formuscle tears and stiffness. The restoration of flexibility is as importantto the outcome as the restoration of strength.

Muscular dysfunctions

The commonly identified muscular dysfunctions in the equine athlete aremuscle deficiency (weakness or stiffness), tension, and muscle spasm. Tensionis defined as muscle contraction beyond physiological needs. Muscle spasmis a reflexive contraction mediated at the spinal cord level, presumablydesigned to protect and immobilize an injured part. Muscle spasm is a componentof all acute injuries-as the reactive tissue of the musculoskeletal system,muscle responds to insult in the only way it can-by contracting. Persistentmuscle spasm is a painful pathologic contraction resulting in limitationof motion and continued morbidity.

The attending veterinarian should evaluate all acute athletic injuries,and perform diagnostic imaging as indicated.

PT in the form of immediate controlled mobilization is the treatmentof choice for most acute injuries not requiring surgery. Immobilizationis required when there is anatomic instability (i.e., most fractures). Controlledmobilization is indicated for most soft tissue injuries, including partialtendon tears ("bowed" tendons).

Benefits

The benefits of early mobilization include:

* Increased local circulation to enhance healing,

* Reduced swelling via improved lymphatic and venous drainage,

* Prevention of motion-limiting adhesions, and

* Restoration of the muscular system to earlier function.

When applied properly, recovery time is shorter and more complete thanwhen using conventional methods.

Mobilization must be controlled. Excessive exercise causing lamenessor pain is contra-indicated; pasture turn-out is not advisable, as the exerciseis totally uncontrolled. Mobilization is most effective when institutedimmediately following injury, as long as it is performed in a controlledfashion under veterinary supervision.

Immediate controlled mobilization

In the acute phase, the goal of treatment is to gently restore functionwhile reducing pain and swelling. Cold hydrotherapy or ice is effectivein reducing swelling and alleviating pain. Cold is used to provide localanalgesia; during cold therapy, the injured part is very gently manipulatedto gradually restore normal motion. Manipulation should follow the naturalmotion of the joint. Easy motion within the comfortable range serves toslowly break muscle spasm. Active motion, with gentle muscle contractionis beneficial as it activates the "lymphatic pump." For leg injuries,this active motion can be accomplished by "asking" the horse topick up its foot as if to pick out the hoof. This motion may be repeateda few times, and the affected joint(s) gently passively flexed and extended.

Only a few repetitions (five repetitions maximum) of this flexion exerciseare required; excessive repetitions cause fatigue and stiffness. Duringthe acute phase, frequent short therapy sessions are required (ideally,every two hours); as treatment progresses, a twice-daily schedule is recommended.We have developed a simple regimen of equine distal limb exercises, whichare easily performed by owners or caretakers. All exercises should be comfortablefor the patient. Stretching is contraindicated in the acute; stretchinga muscle in spasm causes tearing of fibers, producing more pain. Althoughthe patient may be "sore," there should be no indication of pain,such as flinching or sudden retraction of the limb. The horse should berelaxed and willing during the therapy sessions, and should show an increasedlevel of comfort following treatment.

Light hand walking is indicated when the horse can walk without apparentlameness. Stall rest and bandaging for support are required to prevent overuseof the injured part. Gradually, a controlled exercise program can begin.

Controlled exercise program

A controlled exercise program may be instituted for rehabilitation ofathletic injuries, for post-operative rehabilitation, or for chronic orthopedicconditions (such as navicular syndrome and osteoarthritis). Equine athleticcareers are prolonged by judicious use of controlled exercise programs becausegeneral fitness can be maintained.

When managing musculoskeletal injury, the necessity of complete restis the exception rather than the rule. Following acute injury, hand walkingis advised as soon as lameness is no longer evident. Light trotting is institutedgradually, on an as-tolerated basis. Lameness, and increased local tenderness,heat or swelling are indications that exercise has been excessive. Localadjunctive therapy, such as cold hydrotherapy, is used in addition to exercise.Support wraps are advisable, as is regular shoeing, with attention givento prevailing conditions.

Exercise prescription

The exercise prescription should be modified weekly at first, then monthly,based on veterinary examination and diagnostic imaging when appropriate.An exercise prescription should include the following components as a minimum:

* Range of motion exercise, when applicable; specific exercise(s)and number of repetitions (i.e., flex carpus five times) and frequency perday;

* Specifics of general exercise (e.g., walk in hand five to 10minutes per day);

* Shoeing prescription;

* Medications ordered;

* Ancillary aids, such as hydrotherapy, massage, and leg bandaging.

An open conversation with the owner and/or trainer is imperative. Theexercise prescription may be modified depending on the handler's abilities,the facilities, and the horse's disposition. It is the veterinarian's dutyto caution against potentially harmful practices. The following are contraindicated:

* Anything that produces increased swelling, such as the use ofheat in acute leg injuries;

* Anything which causes discomfort to the patient, such as excessivemanipulation of an injured part, activity producing lameness, or stretchinga muscle in spasm; any therapeutic modality which is unpleasant to the horsewill increase muscle spasm and tension and is therefore harmful, even ifproven useful in other patients;

* Immobilization and complete rest (except where necessary dueto fracture, etc.);

* Uncontrolled exercise, such as pasture turn-out;

* Any exercise program, including massage or chiropractic manipulation,which has not been approved by the attending veterinarian.

Case example

An 18-year-old QH/TB gelding presents with acute right forelimb lamenessafter being turned out in pasture. The horse has a history of "bonespavin" and has required intra-articular medication in the past. Thehorse is currently serviceably sound and is used as a basic equitation schoolhorse.

Physical examination and ultrasonography reveal acute tearing of theright fore distal check ligament. There is an associated mild lameness atthe walk, and a marked lameness at the trot. The check ligament area isswollen and warm, and pain is evident on local palpation.

The initial recommendation is cold hydrotherapy with gentle range ofmotion exercises (carpal and distal limb flexion, three slow repetitionsonly) performed twice daily. Support wraps are applied in the forelimbs,and the horse is confined to a stall. Phenylbutazone is administered (1gram by mouth twice daily) for five days. Lateromedial radiographs of theforeleg are obtained to evaluate alignment of the bony column, and correctiveshoeing is performed to raise the hoof angle using a 2º-wedge pad.

After seven days, there is decreased local swelling and no lameness atthe walk. Range of motion exercises are increased and hand walking is instituted.The treatment sequence is:

* Hydrotherapy

* Five limb flexions

* Hand walking once around the arena

* Five limb flexions

* Stall confinement

* Leg wraps are maintained in the stall.

The next week, the horse is ridden at the walk, using leg wraps for support.By three weeks following injury, there is no overt lameness at the trotin the right forelimb. However, the gelding is "off" in the hindquarters,presumably from the effects of stall confinement on the chronic tarsal osteoarthritis.Exercise is gradually increased to include riding at the trot.

Two months following injury, the horse is ridden in half-hour basic lessonsthree times a week. The exercise is limited to walking, a moderate amountof trotting, and very little cantering (once around the arena). By six monthsafter injury, a full lesson schedule is resumed. Jumping and turn-out arenot allowed for a full year after the injury.

Conclusions

Physical therapy is important in the management of equine musculoskeletalinjury. Principles proven in human medicine are being successfully appliedin horses.

The knowledgeable practitioner should be able to write a complete exerciseprescription for an equine athlete, and be able to recognize and adviseagainst potentially harmful adjunctive treatments.

Veterinarians should be sufficiently informed to be able to direct physicaltherapists in patient treatment, and should seek the active involvementof these trained specialists in their practices.

Dr. Kraus-Hansen is a 1995 graduate of Tufts UniversitySchool of Veterinary Medicine and a 1993 Diplomate of the American Collegeof Veterinary Surgeons. She studied physical therapy with her father, HansKraus, MD (deceased), a pioneer in human sports medicine and rehabilitation.She currently operates a general equine and surgical referral practice inMonroe, Wash.