Janet B. Van Dyke, DVM, DACVSMR
Canine Rehabilitation Institute, Inc. Wellington, FL, USA
Canine rehabilitation is the application of physiotherapeutic techniques to evaluate and treat musculoskeletal impairments in our canine patients. It incorporates the use of objective outcome measures (goniometers, girthometers, etc.), manual assessments (including palpation, joint glides, and neurological assessment), gait analysis, and special tests brought from the field of human physiotherapy. This allows the therapist to tease out the specific structure and tissue type causing the impairments. The therapist evaluates the presenting complaint, subjective information from the owner, and objective assessment carried out during the examination to create a problem list. Each item on the problem list is addressed in the plan of care.
Therapeutic plans generally involve a combination of manual therapies (joint mobilizations and soft tissue mobilizations), physical modalities (laser, therapeutic ultrasound, e-stim, shockwave), and therapeutic exercises. The modalities are generally used to prepare the tissues for the manual therapies and therapeutic exercises. Physical modalities should never be the sole therapeutic method applied to any patient. Therapeutic parameters for each modality are chosen based upon the acuity of the injury, so the therapist must be well versed on the definitions of the acute, subacute, and chronic phases of healing.
In the acute phase of healing, the initial damage is present along with an inflammatory response. During this phase, modalities are chosen to treat the acute pain, prevent exacerbation of the pain, and to prevent compensatory dysfunction that occurs secondary to pain. In the subacute phase of healing the inflammatory response has ended, but the tissues remain fragile and at high risk of slipping back into inflammation. During this phase, modalities are chosen to enhance tissue healing, resolve compensatory pain, and prevent exacerbation of the underlying injury. In the chronic phase of healing, tissue healing is underway but incomplete. During this phase, modalities are chosen to help gain complete resolution of the underlying injury, reconditioning of injured tissues, and whole-body reconditioning.
The physical modalities fall into four categories: thermal, electrical, sound, and electromagnetic. Choosing which modalities to use should be based upon evidence-based medicine principles. According to the Evidence Based Veterinary Medicine Association (EBVMA), “Evidence-based medicine is the effort to place all medical decisions on the strongest scientific proof (evidence) available.” A physical modality is a device or application that delivers a physical agent to the body for therapeutic purposes. In other words, this is the transfer of energy for therapeutic purposes.
The most commonly used physical modalities in veterinary practice include cryotherapy, neuromuscular electrical stimulation, therapeutic ultrasound, lasers, and extracorporeal shock wave. Cryotherapy can be applied through ice baths, ice massage, ice packs, vapocoolant gel, or ice/compression units. Cryotherapy causes vasoconstriction, reduced cell metabolism, decreased nerve conduction velocity, analgesia, reduced edema, and decreased muscle spasm. The mechanism of action of cryotherapy in decreasing inflammation is vasoconstriction, decreased histamine release, decreased edema and decreased protease release. The mechanism of action for decreasing pain is via decreased release of prostaglandins, decreased muscle spasm, and decreased nerve conduction velocity. Cryotherapy also lowers the metabolic rate of cells, protecting cellular viability through decreased demand for oxygen and nutrients. This reduces hypoxia, preventing further cellular destruction. Swelling is diminished, leading to less secondary hypoxic injury. However, cryotherapy alone does not eliminate swelling. Some form of compression is essential to accomplish this. Intermittent compression mirrors muscle contractions to force tissue debris into the lymphatic system, thus lowering oncotic pressure and promoting fluid reabsorption.
Cryotherapy has been shown to improve joint range of motion through suppression of excitatory muscle spindle afference. Studies have shown that intermittent pneumatic compression with cryotherapy prevents edema and optimizes lymphatic drainage. Many veterinarians still prefer to use bandages after orthopedic surgery. Studies have shown that cold compression with or without a bandage decreased swelling better than a bandage alone, and that cold compression significantly decreased pain, lameness, and swelling, and improved ROM in TPLO patients treated for 24 hours post operatively. Pneumatic cryotherapy devices are efficacious in reducing inflammation, combine dry cold therapy with intermittent compression, keep the skin surface dry, reducing the chance for infection, and allow for deeper penetrating cold than traditional ice packs.