Rehabilitation therapy for orthopedic conditions (Proceedings)

Annapolis Junction, MD

There are numerous studies indicating the positive benefits of rehabilitation therapy following CCL surgery. In summary, rehabilitation therapy has been shown to improve muscle mass and attenuate muscle atrophy that occurs in the post-operative period, increase stifle joint ROM, especially extension, improve weight-bearing as measured by force plate analysis, and reduce the progression of osteoarthritis.

Rehabilitation guidelines following stifle surgery are structured to direct the clinician in returning dogs to pre-injury activity levels as quickly and safely as possible. Criterion-based protocols eliminate subjective progression through rehabilitation by dictating the milestones that must be reached in order to progress to the next phase. The rate of progression can differ between dogs and is dependent on the individual rate of healing and the demands of the dog's activity level. Also, clinicians should prescribe therapeutic interventions within each phase that are tailored to the patient's needs. Prescribing therapeutic interventions in a 'cookbook' fashion for each particular diagnosis is committing a disservice to the patient.

Three phases of rehabilitation are included for recovery in dogs: the acute phase, advanced phase, and return-to-play phase (Table 1).

Acute Phase

In the acute phase of rehabilitation, strategies are focused on controlling the effects of inflammation (pain, effusion, loss of motion, and muscle atrophy). The goal of the acute phase is to revise full range of motion, reduce effusion, retard muscle atrophy, and ambulate without assistance (Table 2). Cryotherapy, Laser therapy, NMES, TENS, passive range of motion, and compression of the affected limb can assist in counteracting the effects of inflammation and edema. A combination of low-load sustained stretching, joint mobilizations of the patella and tibiofemoral joints, and modalities to control pain and resultant muscle spasm are commonly performed following CCL surgery.

Cryotherapy

Cryotherapy (Ice compresses) following CCL surgery provides an excellent method to help control pain and inflammation in the immediate postoperative period. Not only is cryotherapy beneficial in the acute phase of tissue injury and inflammation, it is also advantageous after exercise and throughout rehabilitation when inflammation occurs. The effects of cryotherapy include vasoconstriction, decreased blood flow, reduced cellular metabolism and permeability, attention of traumatic or exercise-induced edema, and decreased muscle spasm. Another primary effect of cryotherapy is analgesia, which is thought to be a result of decreased sensory and motor nerve conduction velocity that occurs when nerve fibers are cooled.

Cryotherapy following CCL surgery can be accomplished with a variety of methods. The simplest way is by placing crushed ice in a sealed plastic bag and than wrapping the bag in a thin towel. Alternatively, you can prepare a mixture consisting of two parts water and one part alcohol in a double-sealed plastic bag and place it in a freezer. The resulting pack should be frozen slush that conforms to any surface. Apply the cold pack to the stifle for 15 to 20 minutes immediately after surgery while the patient is still recovering from anesthesia. Be careful when applying cold packs to patients that are already hypothermic postoperatively. Following CCL surgery cryotherapy is used for the first three or four days to help minimize inflammation, swelling, and pain from surgery. Apply the cold compress for 15 to 30 minutes three or four times a day. Monitor the patient for discomfort, and assess the tissues periodically for signs of adverse effects such as white or pale areas. Do not use cryotherapy in patients with poor or absent pain sensation. Cryotherapy will be a valuable part of the home rehabilitation program once the patient is discharged (Tables 1-3).

Laser Therapy

L.A.S.E.R. (Light Amplification by Stimulated Emission of Radiation) therapy is a modality that is commonly used in our practice during the postoperative period. Laser therapy, also known as phototherapy and low level laser therapy, involves the application of low power coherent light to injuries and lesions to stimulate healing and reduce pain. It is used to increase the speed, quality and strength of tissue repair, resolve inflammation and give pain relief.

Using photochemical processes, laser light inserts bio-photons into damaged cells. The cells begin to produce energy (ATP), which improves their function and assists their division. Laser therapy promotes healing in the postoperative period because it penetrates the skin, increases the ATP and activates enzymes in the targeted cells. Laser therapy has been shown to stimulate growth factor response within the cells and tissue as a result of increased ATP and protein synthesis. It has also been shown to improved cell proliferation. The effects of pain relief is due to a result of increased endorphin release. Laser therapy has also demonstrated the ability to strengthening the immune system response via increasing levels of lymphocyte activity.

The main advantages of the use of Laser therapy following CCL surgery is due to its benefits of enhanced wound care and tissue repair, anti-inflammatory properties, and ability to assist with pain control. Following CCL surgery, laser therapy is typically performed daily for the first 24-72 hours followed by weekly treatments and is targeted to the incision as well as the stifle joint. The specific use and details of laser therapy can be found elsewhere within this text.

Neuromuscular electrical stimulation

Neuromuscular electrical stimulation (NMES) is another modality which is useful following CCL surgery. NMES is a therapeutic modality indicated for treatment of muscle atrophy, pain, edema, muscle spasm, increasing ROM, muscle strengthening and re-education.

Neuromuscular electrical stimulation (NMES) is used to strengthen healthy muscle or to maintain muscle mass during the early post-operative period, maintain or gain range of motion, facilitate voluntary motor control and temporarily reduce spasticity. Neuromuscular stimulation is achieved by sending small electrical impulses through the skin to the underlying nerves and muscles to create an involuntary muscle contraction.

If the dog is experiencing difficulty producing a strong quadriceps contraction, neuromuscular electrical stimulation (NMES) is indicated. NMES may be performed up to 2-3 sessions per week if needed. The success of NMES depends upon achieving adequate levels of electrical stimulation to provide stimulus to promote strength gains. Intensity levels that are below 50% of maximal voluntary isometric contraction (MVIC) have limited capacity to assist in strength gain beyond volitional exercise alone. Use of this high intensity NMES may be maintained until the involved limb achieves strength equal to 80% of the uninvolved side. NMES should be used as an adjunct to rehabilitation therapy and not in place of rehabilitation therapy.

Range of motion and stretching exercises

Range of motion deficits should also be resolved in the acute phase of rehabilitation. Most often, regaining stifle extension is more difficult, so priority should be placed on achieving extension is more difficult, so priority should be placed on achieving extension. The clinician should evaluate the numerous possible sources contributing to a restricted range of motion including: decreased patella mobility, poor quadriceps strength, decreased accessory motion of the tibiofemoral joint, and muscle guarding and tightness.

Interventions should be chosen that address the specific cause of restricted range. A combination of low-load sustained stretching, joint mobilizations of the patella and tibiofemoral joints, and modalities to control pain and resultant muscle spasm are commonly performed following CCL surgery. These exercises help prevent adhesions between soft tissues and bone, improve muscle extensibility, and prevent further injury to joints, ligaments, tendons, and muscles. Additional benefits from range of motion and stretching exercises are pain reduction, enhanced blood and lymphatic flow, and improved synovial fluid production and diffusion of nutrients.

True passive range of motion (PROM) exercise is performed without muscle contraction and is facilitated by a therapist. Complete relaxation is rare in veterinary patients, so most range of motion exercises are active-assisted. It is best to perform these activities in a quiet environment with the patient on a comfortable surface in lateral recumbency. It helps to relax the patient and relieve tension in the hind limb if massage therapy is performed prior to ROM exercises. When performing ROM exercises it is best to involve only one joint at a time while keeping the other joints in a neutral position. The movements should start small and increase until the endpoint of the range of motion is reached and the patient appears to slightly resist. Applying steady pressure for 15 to 30 seconds at the end of flexion and extension of the stifle results in stretching. Fifteen to 20 repetitions performed two to four times a day is likely sufficient.

Following CCL surgery range of motion and stretching exercises are often performed together to help maintain and improve range of motion that is often limited by the soft tissues. It is important that you never exceed range of motion that is comfortable for the patient. Active use of the limb and joint may be reduced if pain is inflicted. It may also be necessary to use analgesics to maximize comfort, however, it is not recommended to fully sedate the patient as they will be unable to respond if the stretching has been taken beyond a tolerable range. When patients are non-ambulatory to mildly weight bearing lame following CCL surgery, both the stifle and the other portions of the body become less extensible and can create secondary problems. Therefore, it's important not to focus only on the stifle but consider the entire patient.

It is possible to objectively assess improved range of motion by using a goniometer. The measurements may be recorded in the patient's medical record and followed over time. The unaffected contralateral stifle can often be used as a reference. It is important to remember that improvements achieved with range of motion exercises will be slow and gradual. Another important factor is safety, and it is recommended to have an assistant restrain the patient during the intial sessions

Therapeutic exercises

One of the most beneficial activities in a rehabilitation therapy program following CCL surgery is therapeutic exercises. In the early postoperative period relatively slow and low impact exercises are initiated. As limb use and patient comfort allow, more advanced exercises should be instituted. Tables 1-3 demonstrate examples of the therapeutic exercise program used in our patients following CCL surgery. These exercises are demonstrated to the owners on the patient at the time of discharge by the therapist. It is beneficial to have the owner practice the exercises on the patient with the therapist so that there is no confusion when performing the exercises at home. Although the tables are set to a timeline (weeks postoperative) it is important to remember that there is no "cookbook" approach and each patient will progress through the rehabilitation program at a different rate. Therefore, the exercises will need to be tailored based on the patient's status during each in-hospital session. In all cases, the stage of healing and the strength of tissues must be considered so that excessive exercise forces are not placed on healing tissues, causing tissue damage.

The ability of the patient to perform the exercises listed in table 1 will depend on the patient having adequate strength and flexibility to participate. These exercises are used if the patient is ambulatory or at least able to bear some weight. Patients that may not be able to stand or support their own weight may benefit from assisted standing. Even short periods of standing provide and opportunity to build strength; aid in proprioceptive training; improve circulation, respiration, and elimination efforts; and enhance a patient's psychological well-being. Using a sling or rolled-up towel under the patient's abdomen can help facilitate short-term assisted standing and walking. This activity may be performed as often as needed for elimination purposes or as often as the patient is able. Following CCL surgery patients typically progress rapidly through this exercise, therefore, increasing this activity 15% to 25% each week may be appropriate.

One of the main exercises listed in table 1 for patients following CCL surgery is slow, short, controlled leash walks. It is important to instruct the owner how to perform this exercise correctly as most owners lead the patient too quickly. Slow walks increase stance time, flexibility, strength, and weight-bearing. Once the patient shows the ability to use the affected hind limb consistently at a slow walk, faster walks may be used which can further develop endurance, strength, balance, coordination, and proprioception.

Additional examples of therapeutic exercises for the acute phase of rehabilitation therapy include torso strengthening, cookies at the contralateral hip, sitting exercises, three leg standing, paws on the counter, and hair scrunchy on the contralateral paw. Specific guidelines regarding these exercises can be found in table 1.

Advanced phase

The advanced phase of rehabilitation is initiated when range of motion is full and effusion and lameness controlled. The goal of this phase is to increase muscle strength and endurance. Higher intensity training can be initiated and should include exercises for all muscles of lower extremity. If the intensity of therapeutic exercises creates an increase in effusion and or lameness, intensity levels are reduced to the previous level (table 4). Progression to higher activity is dictated or restricted by the presence of lameness after exercise.

Since one of the important aspects of rehabilitation in the advance phase is increasing strength it would be helpful for the clinician to understand the concepts of open or closed chain exercises. Open chain exercises are those in which the distal end is free to move (e.g. thera-bands), and closed chain exercises are those in which the distal end is fixed (e.g. sit to stands). Optimal strengthening requires a combination of both open and closed chain exercises. When dogs perform closed chain exercises, clinicians should be cognizant of the tendency to compensate for weak muscles in the kinetic chain. Reliance of the ankle platar flexors and the hip extensors is a common substitution with closed chain exercises following knee injury.

Examples of therapeutic strengthening exercises that may be used in the advanced phase of therapy may be found in table 2. One such exercise which will help to improve strength and endurance is walking on inclines. Walking on inclines provides a low-impact method to strengthen the gluteal muscles as well as the cranial and caudal thigh muscles. It is best to start with small inclines and progress as the patient is able. Walking downhill may also result in increased hock, stifle, and hip flexion during the stance phase of gait because the limbs are advanced further cranially under the body as the dog walks downhill. Although walking results in some joint motion, the joints do not undergo their maximum range of motion, therefore, it is important to perform ROM exercises are previously described.

Often, exercises designed to improve dynamic stability are added in this phase. Although there is no literature to support the inclusion of such exercises, there is a theoretical framework for including such exercises based on basis science and applied research. Balance exercises using unstable surfaces (wobble boards) are included.

In addition to the exercises listed, under water treadmill therapy is an excellent means of increasing strength and endurance and may be initiated during the advanced phase. The benefits of UWTM therapy following CCL surgery include assisted weightbearing, improved strength and endurance, cardiovascular fitness, range of motion, agility, balance, and proprioception; as well as decreased joint effusion and peripheral edema. These benefits are due to specifically to buoyancy, hydrostatic pressure, viscosity, resistance, and surface tension. Buoyancy decreases the amount of weight placed on the affected limb and therefore, decreases stress at the surgical site. Hydrostatic pressure provides constant pressure to the affected limb submerged in water which may aid venous and lymphatic drainage from an edematous surgical site. Hydrostatic pressure has also been reported to decrease pain by providing a phasic stimulus to the sensory receptors to decrease pain perception. The viscosity of water provides resistance which may help to strengthen muscles and promote cardiovascular fitness. Surface tension aids in strengthening as the the joint undergoes increased motion and work to break through the water's surface. The specific details of UWTM therapy can be found elsewhere in this text.

Although the benefits of UWTM therapy has been well described the exact time in which this modality should be initiated following CCL surgery is still being debated. In addition, it is recognized that not every clinician will have access to UWTM therapy due to cost and space constraints. Clinicians who do not have access to this form of therapy should feel confident that they can return their patient's to full function following the use of the other modalities, manual therapies, and therapeutic exercises described. In fact, a recent report in humans evaluating the effects of UWTM therapy vs ground exercises found no significant difference.

Progression of aerobic condition often includes hill walking and an under water treadmill therapy program that is usually initiated in this phase of rehabilitation. To start running, the dog's injured side quadriceps strength must be restored to at least 80 % of the uninvolved side, and sufficient healing of the injured structure must have occurred (e.g. TPLO approximately 8 weeks). Bone healing is usually sufficient at 8 to 12 weeks. Return of muscle mass is usually sufficient at 12 weeks as long as an appropriate post-operative rehabilitation therapy program was followed.

Return-to-sport-phase

The goal of the return-to-sport phase is to prepare the canine athlete to return to the demands of the competition. The dog is allowed to enter this phase when instance resistance training and a running program do not increase effusion or lameness. In humans, therapeutic exercise interventions follow the SAID (Specific Adaptations to Imposed Demands) principle. This concept is based in the notion that the body will adapt to accommodate to the stress and strains applied to it. Therefore, exercises should attempt to mimic the demands of activities required for the canine athlete to successfully return to sport.

The return-to-sport phase is characterized by agility training and sport-specific exercise. Less complex agility drills should be used initially, moving to more complex agility drills. The volume of agility activities should be graded by frequency, duration, and intensity. Only one variable should be modified at one time, otherwise it is difficult to determine what was the factor that caused an adverse response (increased pain or effusion) to the treatment. Sport-specific activities are introduced and progressed in the same manner. Practice drills are started, leading to competition level activities.

Rehabilitation exercises are commonly categorized as open or closed chain exercises. Open chain exercises are those in which the distal end is free to move (e.g. knee extension), and closed chain exercises are those in which the distal end is fixed (e.g. squat). Optimal strengthening requires a combination of both open and closed chain exercises. When athletes perform closed chain exercises, clinicians should be cognizant of the tendency to compensate for weak muscles in the kinetic chain. Reliance of the ankle plantar flexors and the hip extensors is a common substitution with closed chain exercises following knee injury.

Often, exercises designed to improve dynamic stability are added in this phase. Although there is no literature to support the inclusion of such exercises, there is a theoretical framework for including such exercises based on basic science and applied research. Balance exercises using unstable surfaces (wobble boards) are included. Progression of aerobic condition often includes hill walking and an underwater treadmill therapy program that is usually initiated in this phase of rehabilitation. To start running, the dog's injured side quadriceps strength must be restored to at least 80% of the uninvolved side, and sufficient healing of the injured structure must have occurred (ie., for a TPLO approximately 8 weeks). Bone healing is usually sufficient at 8 to 12 weeks. Return of muscle mass is usually sufficient at 12 weeks as long as an appropriate post-operativerehabilitation therapy program was followed.

Canine athletes are cleared to return to sport when they have progressed through all phases of rehabilitation without symptoms and have met the criteria of return-to-sport testing. Return-to-sport testing involves symmetric thigh circumference, strength testing and gait analysis.

References furnished upon request