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Musculoskeletal: physiotherapy

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Podcast: Musculoskeletal: physiotherapy

Introduction

Definition

  • Physiotherapy or physical therapy can be broadly defined as the restoration of movement and function.
  • In the horse it is mainly used in the musculoskeletal system particularly in cases of poor performance, neck/back/pelvic pain, soft tissue injuries particularly involving tendons and ligaments, following trauma and wounds, and some muscular and neuromuscular disorders.
  • The sciences of functional biomechanics, neuromotor control, and the sensorimotor system in the spine, pelvis, and peripheral joints all help to explain and justify the use of physiotherapy in the horse and other species.
  • Specific to the equine physiotherapist is also the assessment of the rider and the horse-rider interaction, plus the tack and training aids that are used.
  • The interaction and co-operation of the equine veterinarian and physiotherapist is a central part of the investigation, management, and rehabilitation of the equine athlete. It is also important in helping to keep horses in competition healthy and performing to their maximum capacity.
  • Any treatment plan should be based on the careful assessment of the patient by veterinarian and physiotherapist, a reasoned process of selection of appropriate interventions or treatments, and the careful follow up and re-examination of the patient. The whole process should be based on the best available evidence at all times.
  • The physiotherapist’s aim in this process is slightly different to the veterinarian in that the former is looking to make a functional diagnosis (identification of existing or potential impairments, activity limitations, participation restrictions, or abilities/disabilities). The veterinarian is primarily focused on reaching a pathoanatomical diagnosis (what the pathology is and where it is located).
  • The main physical interventions used in equine physiotherapy are manual therapies, specific motor retraining, exercise prescription, and electrophysical agents, in association with education and advice to restore function and improve the quality of life of the horse.
Print off the Owner factsheet on Complementary therapies to give to your clients.

Role and responsibilities of the animal physiotherapist

  • After veterinary examination and diagnosis, physiotherapy is used to:
    • Relieve pain.
    • Restore movement.
    • Improve function and potential.
    • Improve the quality of healing, NOT the speed, ie physiotherapy does not accelerate healing.
  • Two modalities are used - therapeutic machines for 'passive' cellular stimulation, and apparatus for active rehabilitation which restores strength and 're-educates' muscle and nerve function.
  • The machine phase of therapy is a supportive treatment until controlled exercise and other rehabilitative techniques can be introduced.

UK

  • In the UK, following four years of training with a recognized school of physiotherapy to become a 'chartered physiotherapist', animal physiotherapists must see practice with two veterinary practices and become a member of the Association of Chartered Physiotherapists in Animal Therapy.
  • A code of professional conduct for animal physiotherapists has been agreed between the Royal College of Veterinary Surgeons and the Chartered Society of Physiotherapists.
  • They are bound by the Veterinary Act.
  • Non-chartered physiotherapists, ie lacking formal training, can use the title 'physiotherapist'.

Veterinary examination

Physiotherapeutic modalities

Extracorporeal shockwave therapy (ESWT)

Thermotherapy (cold therapy)

  • One of the oldest and simplest physical treatments in the horse is thermal therapy. Heat Heat therapy or cold therapy Cold therapy can be administered in a number of ways from simply applying water from a hose to specially designed therapeutic boots.
  • The application of cold therapy is the most common and its physiological benefits include reductions in local circulation, inflammation, tissue swelling, and pain sensation.
  • Cold therapy is most effective if used in the acute phase post injury or surgery.
  • The precise effect of cold therapy on various equine musculoskeletal injuries has hardly been studied and research is needed to create evidence-based guidelines on the effective duration, frequency, temperature, and safety of application that will optimize outcomes after injury.

Magnetic fields

  • Pulsed electromagnetic field therapy (PEMF) Magnetic field therapy has been used for over 30 years in treating equine musculoskeletal disorders, but its use is still controversial.
  • An electromagnetic field is generated by the passage of an electrical current (low frequency and short pulse duration) through a circular coil of wires. The pulsed field is generated from an applicator and transmitted through tissues. It is absorbed by low impedance vascular tissues, such as muscle and nerves, or tissues which are edematous, contain effusions, or have recent hematoma. It has no heating effects within the tissues.
  • It is thought that PEMF therapy may have beneficial effects on damaged tissue cells, particularly at the cellular level, although this is not definitively confirmed. This may involve the restoration of cell membrane potential, transport, and ionic balance by either a direct ionic transport mechanism or activation of sodium/potassium pumps. PEMF therapy is said to: increase the number of WBC, histiocytes, and fibroblasts within wounds; improve the rate of dispersal of edema; increase the absorption of hematoma; help resolve the inflammatory process; promote the orientation and early deposition of collagen and fibrin fibers; and stimulate osteogenesis.
  • It is known that bone can develop a piezoelectric potential on its external and internal surfaces and PEMF has been suggested as a technique that can improve bone healing and remodeling. It has been used for this for many years in human and equine medicine but most scientific studies have failed to show any significant improvement in either healing or remodeling.
  • In the equine it is used either within full-body rugs containing coils, to target tissues within the back, neck, pelvis or trunk, or as paired coils, of different sizes and often within plastic pads, that are strapped or bandaged to a limb to be treated for soft tissue or bony injuries.

Muscle stimulation Electrotherapies

  • Aims to restore pre-injury muscle strength and function by stimulating individual muscle contraction; applied as soon after injury as possible, it may prevent loss of muscle response to stimulation.
  • Stimulation is usually focused over the muscle motor units, generally in the longitudinal center of the muscle.
  • Pulse per second (pps) needs:
    • 'Slow twitch' fibers require stimulation at 10 pps, 'fast twitch' require 30 pps.
    • 5-15 pps - improves tone, joint mobility, capillary bed density.
    • 15-25 pps - promotes endurance.
    • 30-40 pps - to strengthen muscle.
Faradism
  • Muscle stimulation using faradic currents is not well-tolerated by the animal.
  • 'Active' pad placed over the motor unit of the affected muscle.
  • Intensity is increased slowly until muscle contracts, allow 10 contractions, then move pad to another motor point.
  • Two 15 min sessions daily.
Neuromuscular electrical stimulation (NMES)
  • Achieve full contraction of a large muscle belly by mimicking the pattern of intact nerves.
  • The FES unit is one of the most commonly available machines.
  • NMES was first used in the human for the rehabilitation of patients with spinal cord injury to generate muscle movement.
  • Used to prevent atrophy of de-enervated muscles and for a large range of nerve and muscle conditions to decrease pain or atrophy and improve function.
  • Proper placement of the electrodes and increasing the amplitude to effect is the best way to develop a treatment plan. The intensity is determined by what the animal will tolerate and the number of repetitions should start low (8-15 contractions per session), and increase gradually over the next 3-5 weeks. One to five sessions per week may be necessary depending on the injury and the goals of the physiotherapy.
  • Indicated as a supportive therapy for fractures, tendon injury, joint strain, sacroiliac subluxation, muscle tears, nerve transection or damage, hematoma, following surgery and other trauma to reduce potential muscle atrophy.
  • Individual animal intolerance of the procedure and skin irritation from the contact gel.

Transcutaneous nerve stimulators (TENS)

  • Pain relief via segmental inhibition through pain gating mechanisms which requires  activation of larger diameter fibers in the peripheral nerves, which subsequently helps block nociceptive activity in smaller afferents. Electrical stimulation of peripheral nerves can stimulate a central release of endogenous opiate-like substances leading to a descending inhibitory effect on pain.
  • Indications include pain modulation in acute situations associated with surgery or trauma, controlling chronic musculoskeletal pain such as osteoarthritis, wound healing, stimulation of de-enervated muscles, Iontophoresis, and edema reduction.
  • Battery operated.
  • Used in human medicine for pain relief during labor. Large amount of research to support the use of TENS in humans for a variety of painful conditions; a large portion of the recommendations for equine use is assumed from this human literature.
  • Aims to block somatosensory input at the dorsal horn of the spinal cord.
  • Source of pain must be identified accurately, and electrodes placed so that current passes through source of pain.
  • 'Block' C fibers (dull, chronic aching pain) and A fibers (sharp pain).
  • Contraindicated in infectious or septic conditions, pregnancy, and near or through the thoracic cavity.
  • There is limited current research into the use of TENS therapy in horses. Possible use in percutaneous electrical nerve stimulation to help the symptoms of trigeminally induced headshaking.

Therapeutic ultrasound Musculoskeletal: therapeutic ultrasound

  • Therapeutic ultrasound is a physiotherapy treatment that uses high-frequency sound waves to produce both thermal and non-thermal effects in mainly soft tissue structures to improve healing and remodeling of injuries.
  • It is particularly useful in improving wound healing, remodeling scar tissue, reducing edema and soft tissue filling in limbs, improving flexibility of movement after injury and fibrosis, and treating muscle injuries.
  • Non-invasive technique with wide range of applications.
  • Easy to apply once instructed by trained person such as physiotherapist. Owners and trainers may be able to treat the animal under instruction saving costs and increasing frequency of treatment.
  • Ultrasound has the greatest penetration of any therapeutic modality and tissues can be damaged if it is used inappropriately - it should only be used in those cases where there has been a full veterinary evaluation.
  • Tissue damage can result before there is a pain response in the patient. Should not be used in proximity to open wounds or metal implants, or in cases of cellulitis, infection, unstable fractures or surgical incisions.

Low level lasers Musculoskeletal: laser therapy

  • There are four classes of lasers, with the class IV laser being the most common choice for equine practice; these low-level lasers work in a range less than 500 mW, and the wavelengths vary from 540-1060 nm.
  • Laser therapy has anti-inflammatory and analgesic effects.
  • It stimulates cellular metabolism, directly activates mitochondrial calcium channels, upregulates ATP production and synthesis, increases fibroblastic activity, increases cellular division, fibroblast migration, and production of cellular matrix.
  • It has been shown that prostaglandin E2, tumor necrosis factor-a,interleukin-1b, plasminogen activator, and cyclooxygenase-1 and -2 are all manipulated with the use of laser therapy, producing a decrease in inflammation. The anti-inflammatory effect is via stimulation of prostaglandins leading to vasodilation.
  • Laser therapy is beneficial on wounds and tendon and ligament injuries, as it increases cellular proliferation and collagen synthesis leading to more rapid healing of the damaged tissue. There is conflicting evidence regarding the effect of laser on second-intention wound healing, because some studies have shown no significant differences in epithelialization or wound contraction.
  • The effects of laser therapy on bone are unknown in the horse, however, there have been several studies showing benefits in dental procedures in humans, leading to bone repair and regeneration.
  • Minimal research has been done in equines in terms of effects on tendon and ligaments and joints and cartilage.
  • Proper use of low-level laser therapy depends on the machine used. Considerations are wavelength, pulse frequency, and time of application.
  • Often for injuries treatments begin on a daily basis then decrease over time depending on response to treatment. Treatment time varies from 5-30 min depending on a variety of factors.
  • Potential complications include overheating the tissues with overuse or incorrect use. Care should be taken to follow the appropriate machine indications and protocols. The use of laser therapy can damage both the patient’s and the administrator’s cornea. Protective eyewear should be worn when performing laser therapy, and eye shields should be placed on the horse if the treatment is in the head or neck region.
  • Indications for use cited in the literature include: synergistic use with stem cell Stem cell techology: overview and platelet-rich plasma treatment Platelet-rich plasma therapy; tendon and ligament injury; chronic joint disease; synovitis, osteoarthritis; back pain/injury;  wound healing; pain relief; and some neurological injuries.
  • Contraindications for use include: pregnant mares (unknown effect); young, growing animals (unknown effect on physes);  malignancy; hematological disorders; febrile patients; and use near the ocular tissues.
  • Laser has also been used as an acupuncture Acupuncture: overview tool.

Vibration therapy Vibration therapy

  • Vibration plates have now been developed for the equine by a variety of companies but the scientific evidence for their effectiveness in the horse is limited.
  • The mechanism of action has been studied in the human but there is limited data in the equine. The plate provides mechanical energy in the vertical and/or horizontal planes. The magnitude of the vibration which is produced depends on the amplitude of the motion and the speed of acceleration. It is postulated that vertical vibration is more likely to mimic the natural movement of the horse.
  • It is thought that vibration plate therapy may improve the cardiovascular and lymphatic circulations by continuously causing involuntary muscle contractions (30-50/sec). This circulatory improvement may benefit the horse by enhancing the oxygenation of tissues, removing toxic and metabolic waste, and increasing inflammatory cell recruitment. It is stated that vibration therapy may promote joint stability, by stimulating and strengthening associated muscles, in the human knee and equine stifle.

Acupuncture

Rehabilitation

  • Following injury the animal may moves differently to cope with the associated pain and dysfunction.
  • The change in movement, for example, a shortened stride, may become habitual and the limb needs to be 're-educated' to use a sequence of movements that restore the correct reflex pattern of movement.
  • Correct movements have to be practiced without pain.

Massage and passive movement

  • Aims to improve circulation, provide pain relief by reducing edema and muscle spasm, breakdown or prevent early adhesions, and stretch contractions.
Hand
  • Hand - firm strokes driven by the arm and shoulder in the direction of venous return.
  • Avoid creating discomfort by going against the lie of the coat.
  • Strokes may be direct compression, linear or circular.
  • Massage for 10-30 min a day.
Friction
  • Use the middle finger with the index placed on top as reinforcement.
  • Use linear strokes in the direction of tissue fibers; avoid moving skin independently of underlying tissue.
  • Give on alternate days for up to 7 min, and follow with general massage.
Ice
  • Rub ice cube over affected area.
Machine
  • Creates vibration and does not require any expertise to use.

Hydrotherapy Hydrotherapy

  • In the equine patient the modalities of hydrotherapy most often used are underwater treadmill exercise (over ground or in ground units), and swimming (circular or straight pools).
  • In addition, cryotherapy (cold water application or immersion such as standing salt water spas or whirlpools) have been extensively used in treating acute soft tissue inflammation, pain, and swelling. 
  • Treadmill and swimming exercise are reported to reduce stresses placed on limbs, improve the range of motion of joints, improve muscle aerobic capacity and strength, increase cardiovascular endurance, and decrease pain and inflammation.

Treadmill

  • Horse must move evenly to keep up with the moving belt and is very useful to restore even gait.
  • Ensure treadmill is facing a wall.
  • Start at slow speed, 2 min, and increase amount daily over a 10 day period until each session lasts about 20 min.

Walkers

  • Walkers which do not require tying the horses head allow a more natural gait.
  • Allow equal time walking in both directions, 5 min initially, working up to 20-30 min sessions.

Weights

  • This technique permits increasing workload to specific groups of muscle that may have wasted following injury.
  • Use weights purchased from a sports shop and strapped to limb, or add weight to shoe on injured limb.
  • Combine with walker.

Core training

  • The activation and strengthening of the epiaxial back muscles as well as the abdominal and sublumbar muscles is very important for good posture and stability of the back.
  • A whole series of exercises have been devised to help achieve this including: dynamic mobilization exercises using baits such as carrots; core strengthening exercises; balancing exercises; exercise at different gaits; and working on circles, gradients, with poles, and over jumps. 

Other

  • In addition to specific techniques described above, normal exercise must be reintroduced slowly so that horse returns to its pre-injury activities.
  • It is essential that this occurs during the remodeling phase of tissue repair (see tendon injuries Flexor tendon: trauma) so that tissue regains maximum tensile strength.
  • Training courses, eg poles, placed at even distances to encourage even cadence before riding.
  • Lunge in tack to increase fitness and even gait before riding.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Clayton H M (2016) Core training and rehabilitation in horses. Vet Clin North Am Equine Pract 32 (1), 49–71 PubMed.
  • Davidson E (2016) Controlled exercise in equine rehabilitation. Vet Clin North Am Equine Pract 32 (1), 159–165 PubMed.
  • M R King (2016) Principles and application of hydrotherapy for equine athletes. Vet Clin North Am Equine Pract 32 (1), 115–126 PubMed.
  • Schlachter C & Lewis C (2016) Electrophysical rherapies for the equine athlete. Vet Clin North Am Equine Pract 32 (1), 127–147 PubMed.
  • McGowan C M, Stubbs N C & Jull W D (2007) Equine physiotherapy: a comparative view of the science underlying the profession. Equine Vet J 39 (1), 90-94 PubMed.
  • Buchner H H F & Schildboeck U (2006) Physiotherapy applied to the horse: a review. Equine Vet J 38 (6), 574-580 PubMed.
  • Porter M (2005) Equine rehabilitation therapy for joint disease. Vet Clin North Am Equine Pract 21 (3), 599-607 PubMed.
  • Bromiley M (1994) Physiotherapy for equine injuries. Equine Vet Educ 6, 241-244.

Other sources of information

  • McGowan C M & Goff L (2016) Animal Physiotherapy. 2nd edn. Wiley-Blackwell, UK.
  • Bromiley M (1991) Physiotherapy in Veterinary Medicine. Blackwell Scientific Publications, UK.