Subjective Assessment of the Equine Patient

Original Editor - Sasha Chelin Top Contributors - Shaimaa Eldib, Jess Bell, Kim Jackson and Tarina van der Stockt

Introduction

Animal physiotherapy is an emerging profession. Physiotherapists who treat human patients are able to use their skills to treat animals. Animal physiotherapists work alongside a multidisciplinary team and usually receive referrals from a veterinarian. Physiotherapists complete a functional assessment to identify pain or loss of function caused by pain, injury, disorders or disability. Animal physiotherapists are now part of the team of professionals that equine athletes and their riders now regularly access.

Process of Assessment

Equine physiotherapists do not need a pathoanatomic diagnosis to develop management plans for their patients. Rather, they approach the assessment from a functional perspective, observing and noting any movement dysfunctions / impairments that may be contributing to a problem, in addition to careful palpation of the horse.

The following skills are considered useful for equine physiotherapists:

• The ability to communicate well with a horse's owner, handler and trainer

• Excellent observation skills (of the horse in motion and at rest)

• Good understanding of the anatomy, functional anatomy, and biomechanics of the horse

• Being able to carry out functional movement tests, have effective palpation skills and be able to interpret the findings of their assessment

Subjective Assessment

When working with horses, the ability to obtain subjective history is limited - it is very difficult to determine the severity, irritability, nature (SIN) of a condition, its 24- hour pattern and the exact area of pain/ discomfort. Unlike in human physiotherapy, you cannot interview an equine patient, so the animal therapist often has to interview the wider team to find out all the relevant information, including the:

1. Rider - what are they feeling during training?
2. Coach - what they are seeing during training?
3. Owner and Groom - how is the horse at home and has it developed any abnormal behaviours?
4. Veterinarian and other medical professionals - what was found on examination and other investigations?

All of this information can help the therapist to develop his / her treatment plan.

• Background information: It is important to have background information (age, gender etc) so that you can identify the horse and contact the MDT for information
• Discipline, training history, the reason for referral: Provides clues about the type of injury, mechanism of injury and cause of injury (i.e. over-training)
• Present medical history: Consider what the problem is and how it has been assessed. What treatment has been given thus far and how has the horse responded?
• Past medical history: This provides clues as to whether or not a previous injury may be causing the horse's current issue. It also indicates what treatments the horse responds to and if the horse has been provided with enough rehabilitation?
• Special questions /red flags: These are similar to those seen in human patients such as a sudden weight loss, general health issues, respiratory conditions ...etc.

These areas will be discussed in further detail below.

1. Age

Age gives us clues about potential pathologies and can be considered in a differential diagnosis.

Young Horses (2-6 years)

• Developmental problems i.e. osteochondrosis dissecans

• Injuries related to poor motor control to cope with work demands. Still developing soft tissue structures

• Competing racehorses are under huge stress - young thoroughbred horses have been shown to experience a significant number of physiological and anatomical adaptations in response to exercise training

Mid-Aged Horses (7-15 years)

• Sport horses are often competing at their peak at this age, so soft tissue injuries due to overuse are more common - ageing and exercise are considered important risk factors for tendon injury

• Biomechanical problems will also cause soft tissue injuries

• Degenerative joint disease (DJD) may already be present in some horses at this age

Older Horses (15-20 years)

• Wear and tear is common especially in joints (i.e. DJD / arthritis)

2. Gender

Hormonal changes may mimic behavioural changes that are associated with musculoskeletal pain:

• A common behavioural problem can occur in performance mares when these mares exhibit heat or oestrus. Mares begin periods of heat due to increasing day length. In general, these periods of heat last 5 to 7 days out of a 21-day cycle. Clinical signs that affect performance mares include attitude changes, tail swishing, difficulty in training, squealing, horsing, excessive urination, kicking, a decrease in performance, and colic like pain associated with ovulation

• Asking the owner or rider about previous problems with oestrus, or whether there appears to be a regular monthly pattern to the pain or if the mare is experiencing performance-related symptoms can be helpful

3. Length Of Ownership

• During the change of ownership of a horse, it is very rare that all the previous medical history is passed on. We are guided by pre-purchase vetting and unfortunately, not all previous musculoskeletal injuries will be obvious during a vetting

• One of the most effective methods we have to identify musculoskeletal pain or discomfort is a horse's behaviour. However, new owners may not know what is ‘normal’ behaviour for their horse yet

4. Discipline and Training History

• It is important to understand a horse's training level and what discipline it competes in as these factors will help determine the type of injury / problem, the mechanism and severity of the injury

• Finding out about a horse's last competition will provide the therapist with an understanding of:
  • when the horse was (possibly) last put under great strain
  • how long the horse has been out of action

• It is important to gain an understanding of a horse's training programme. This will enable the therapist to determine how often the horse is working and what are it is doing. Questions to consider include whether or not the horse is cross-training and if it participates in a range of work / activities (e.g. pole work, jumping, flatwork, hill work or track work and hacking)

5. Present Medical History

• Find out what the horse's main complaint is or what behavioural issue it is presenting with that has caused the owner to phone an animal therapist (e.g. the horse recently started biting while being tacked up or the horse has stopped wanting to work forward)

• Ask long has the complaint or issue been present for and if the veterinarian has seen the horse. Find out about any investigations, whether or not there was a diagnosis and which medications have been prescribed and for how long

• It is important to understand the horse's 24-hour pattern. Does the horse worsen or improve with work? Is the horse worse on walking out the stable in the morning? How long does it take for the horse to improve?

• Ask if there are any other professionals involved in the horses's care and find out what they did and to what extend it helped (e.g. saddle, fitter, dentist, chiro etc).

6. Past Medical History

Information about a horse's medical history may not always available / accurate

• It is useful to find out what veterinary treatment the horse has had

• It is beneficial to consider:
  • Was there a pre-purchase vetting?
  • What was picked up on this pre-purchase vetting?

Vetting is the process where a veterinarian is asked to conduct a comprehensive general check-up on a horse, including a general check of the horse, an assessment of it walking, performing strenuous exercise, examinations 30 minutes post-exercise and finally another trotting assessment. During this process, certain problems may be discovered. X-rays may also be taken during more extensive vettings. The price of the horse often determines how extensive a vetting is or if there is even a vetting. Some expensive horses or horses who have great potential will be x-rayed every few years as a preventative measure. It is important to note that these horses may not be symptomatic, but the therapist should find out if the horse’s veterinarian has ever recommended further diagnostic tests that were not done by the owner.

7. Red Flags

• Red flags are signs or symptoms that suggest serious pathology may be present.
• The horse's general health should be considered, including if there could be:
  • Metabolic diseases such as Cushing’s
  • Respiratory diseases such as COPD

• Also consider what medications / supplements the horse may be on. Remember that your subjective assessment should give you an indication of:
  • What / where to look for the source of the problem?
  • Whether something is not adding up / making sense - this may require a referral

Objective Assessment

The functional assessment should include:

• Active physiological movements

• Palpation and testing of soft tissues

• Passive physiological joint assessment

• Passive accessory joint assessment

Objective physiotherapy tests in the equine assessment are very much based on functional assessment and palpation skills. The assessment consists of four elements which are described in the table below:

1- Functional Assessment	2- ROM	3- Palpation	4- Special Tests & Neurological Ax
Conformation, Gait, Reflexes	Baited stretches, Reflexes, Limb ROM	Temp, Swelling, Bony landmarks, Muscular	Neurological tests
CONFORMATION: Cannot be changed Usually related to skeletal development and includes a structural joint alignment POSTURE: Can be improved Dynamic Related to muscular tone & activation	It is very difficult to do an active ROM assessment on most of the joints in isolation. Thus we try note ROM in functional movements and test passively. However, we can use baited stretches to test cervical and thoracic movements as well as reflex tests.
CONFORMATION & POSTURE AX Observe the horse standing on a flat, firm surface. First observe the horse’s natural stance – how is the horse most comfortable standing? Now try to make the horse stand as square as possible View from the left, right, front and rear. How easy is it for the horse to stand square/ balanced? When the horse is made to stand square, can he/she maintain the posture? The symmetry of muscle development. Balance of feet. Limb Alignment.

BACK CONFORMATION

Typically horses back should be 1/3 of the body from the highest vertebra of the whither to the point of the hip. Long backed horses are generally more flexible however can be prone to injury as they generally find it harder to work correctly and strengthen their core. Short backed horses are generally strong but more ridged and can be difficult when fitting saddles as they ”run out” of the thoracic spine.

Conformational Faults	Explanation	Predisposed issues
Base Wide	Standing with forelimbs outside the plumbline.	Medial stress on joints, medial splint bone stress
Base Narrow	Standing with forelimbs inside the plumbline.	Lateral sidebone, lateral heel bruises and lateral strain on joints
Toed Out	Toes pointing outward	Inward arc when advancing; results in interference with opposite forelimb especially if combined with base- narrow stance.
Pigeon Toed	Toes pointing inward	Outward deviation of foot during flight (paddling or winging-out) resulting in interference with hind limb
Bowlegged	Varus deformity of carpus	Increased tension on the lateral collateral ligament and medial surface of carpal bones
Knock-Kneed	Valgus deformity of carpus	Increased stress on medial carpal collateral ligaments, outward rotation of cannon bone, fetlock and foot
Camped Out	Entire forelimb from body to ground is too far forward	Seen in navicular syndrome and laminitis
Calf Kneed	Backward deviation of carpus	Carpal chip fractures, injuries to check ligaments
Camped Under	Entire limb below elbow placed too far underbody; can occur with a disease as well as be a conformational fault.	Overloading of forelimbs, shortened cranial phase of stride and low arc of foot flight can lead to stumbling
Buck Kneed	Forward deviation of carpus; knees knuckle forward so dangerous for rider	Strain on sesamoid bones, suspensory ligament,ligament, and SDFT and extensor carpi radialis muscle
Sickle Hocked	Excessive angulation of the hock (<53)	High stress on hock and ligaments
Post Legged		High stress on back of hock joint and the soft tissue support structures
Cow Hocked	Medial deviation of the hocks and accompanied by base wide from hocks to feet.	Excessive stress on hock leads to bone spavin
Base Narrow	Distance between hooves less than centre of the thighs, heavily muscled horses (often accompanied by ‘bowlegs’ with hocks too far apart)	Strains to lateral structures of limb
Base Wide	Distance between hooves greater than distance between centre of thighs; commonly associated with cow-hocks.	Strains to medial structures of limb

HOOF PASTERN AXIS

Although we are not Farriers it is important to understand the hoof conformation and its axis as it may interfere with joints and ligaments above.It is an imaginary straight line running from the centre of the fetlock, through the pastern, continuing straight from the coronet to the ground surface.

• 48 – 55 degree angle =NORMAL

• 45 degree angle or less = SLOPING

• 60 degree angle or more = UPRIGHT

Broken back = when the imaginary line running through the fetlock and pastern is broken at the coronet through to the ground surface.The hoof is at a lesser degree angle compared to the pastern. Strain on the tendons and may cause wear on the navicular.

Broken Forward = when the imaginary line running through the fetlock and pastern is broken at the coronet through to the ground surface. The hoof is at a greater degree angle compared to the pastern. Strain on the joints above.

Gait Assessment

When performing a gait assessment in hand have the horse:

• Walk away from you, past you and towards you

• Trot away from you, past you and towards you

• Walk in a circle with limbs crossing (Turn on the forehand)

• Rein back

• Trot on a circle in both directions (Usually on the lunge)

It is important to note the surface you are examining on as it can influence the lameness if any. As a rule of thumb soft tissue lameness, ie tendons/ ligaments will generally show greater lameness in soft or deep going such as a sand arena,

Joint lameness is usually more evident on hard ground. Trotting on bricks or concrete can sometimes help you assess lameness through hearing the foot- fall rhythm.

GRADING LAMENESS

There are many types of scales which grade lameness. The most widely accepted grading is the American Association of Equine Practitioners (AAEP) scale. The vets commonly use the lameness locator to assess lameness. This is a machine which analysis's movement through motion sensors. It objectively quantifies how a horse moves through space and bears weight.

Grades	lameness is
Grade 1	Difficult to observe ,not consistently apparent,just in weight- bearing or circling in inclines or hard surfaces
Grade 2	Difficult to observe at walk or trotting in straight line , consistently apparent when weight bearing or circling on inclines or hard surfaces
Grade 3	consistently seen at trots under all circumstances
Grade 4	Obvious with marked head nodding or short stride
Grade 5	Obvious with minimal weight-bearing, in motion or and at rest. inability to move.

FLEXION TEST

A flexion test is a preliminary veterinary procedure performed on a horse, generally during a prepurchase or a lameness exam.The animal's leg is held in a flexed position for approximately a minute, and then the horse is immediately trotted off and its gait is analysed for abnormalities and unevenness.

• A flexion test is a preliminary veterinary procedure performed on a horse, generally during a prepurchase or a lameness exam.

• The flexion places stress on the joint capsule and soft tissue of the joint,and sometimes the cartilage and bone, usually accentuating any lameness

that is present, such as arthritis. The horse may take a few uneven steps, or may be lame for several minutes following the procedure.

• Flexion tests are non-specific.

ACTIVE ROM

• It is very difficult to do an active ROM assessment on most of the joints in isolation. Thus we try note ROM in functional movements and test passively. However we can use baited stretches to test cervical and thoracic movements as well as reflex tests.

REFLEXES

VENTRODORSAL LIFT REFLEX (whither lift): Tests: Thoracic vertebra flexion

Preformed:. A firm pressure applied with fingernails, pen cap or blunt hoof pick to the midline of the level of the girth. Causes the horse to ‘lift’ the cranial thoracic region.

LATERAL REFLEX: Tests: Lateral flexion

Preformed: A firm pressure applied with fingernails, pen cap or blunt hoof pick to the bricep femoris line on the contralateral side and around the buttocks. Causes the horse to laterally flex the lumbar region and caudal thoracic region. Watch ROM.

ROUNDING REFLEX:Tests: lumbar flexion

Preformed: A firm pressure applied with fingernails, pen cap or blunt hoof pick to the caudal border of biceps fem bilaterally. Ensure you are standing to the side of the horse and beware of being kicked. The horse will flex. Watch for rotation and ROM.

EXTENSION REFLEX: Tests lumbar or Thoracic extension

Preform: Standing on a box behind the horse, draw your fingers or two hoof picks caudally along the lumbar/ thoracic paravertebral musculature. Observe for quantity and symmetry of movement.

BAITED STRETCHES

Stretches used to test active movement of the cervical and cranial thoracic regions. During these movements the therapist uses a treat to encourage the movement. Remember to compare left and right of lateral movements.

BAITED STRETCHES – CX SPINE

CERVICAL EXTENSION: Guide the horses muzzle upwards and forward with a treat with a treat

CERVICAL FLEXION: Guide horse’s muzzle towards upper chest to effect a nodding movement (at the poll).

For caudal cervical spine

Flexion: For lower cervical/upper thoracic flexion, guide horse’s muzzle down between fetlocks (or observe horse grazing – check for even weight distribution between forelimbs); also guide horse’s muzzle towards sternum to check mid-cervical flexion.

Lateral flexion: Guide muzzle around along horse’s lateral trunk towards the flank and compare range side to side.

Lateral flexion/flexion: Guide muzzle around towards the carpal region and compare range side to side.

BAITED STRETCHES:TX SPINE

It is important to not that when testing caudal cervical spine you will get some thoracic movement of flexion and lateral flexion.

PASSIVE ROM – HEAD & NECK

Extension: Guide muzzle upwards and stabilise with one hand gently over C1. Apply gentle overpressure from underneath the muzzle. Assess end-feel.

Flexion: Guide muzzle towards the upper chest; stabilise with one hand gently over C1 and apply gentle overpressure to the front of the muzzle. Assess end-feel.

Rotation: Stabilise with one hand over C2 and guide horse’s muzzle toward you on an rotatory axis. Apply gentle overpressure via the muzzle. Compare range of motion and end-feel side to side

Lateral flexion: Motion at each cervical level between C3–C6 can be assessed by palpating the ‘opening’ of the cervical vertebra when an assistant laterally flexes the horse’s neck away from the assessor. Or: Stabilise with one hand over the vertebral body to effectively ‘block’ motion from the chosen level caudal, and gently guide the horse’s muzzle toward you, in a lateral flexion direction. Apply gentle overpressure; assess range of motion and end-feel and compare side to side.

PASSIVE ROM – THORACIC SPINE

Passive testing: Very difficult due to deep joint levels, tight connective tissue structures and restrictive facet joint morphology. Globally one can mobilise the whither however there is very little movement.Some rib springing sometimes possible depending on soft tissue tone.

PASSIVE ROM – LUMBAR

Unilateral DV mobs,standing on a tall box or step, apply a gradual downwards force over the transverse process of each consecutive lumbar vertebra. Repeat on the other side.

Central DV L5 & L6,Standing on a tall box or step, apply a gradual downwards force over the spinous processes of L5 and L6. Horses with pain in this area (usually ligamentous in origin) will dip away from the pressure. Non-painful horses will show no response (and no movement should be palpable)

Lateral mobs, Standing on a tall box, stablise the lumbar segment above the testing vertebra and grip the dock of the tail with your other hand. Pull gently on the dock towards you and grade the mobs.

AX of SIJ

ACTIVE TESTING, Weight-bearing weight displacement,Stand on a box behind the horse (or next to the horse if you suspect he may kick). Palpating the tuber sacrale bilaterally, have an assistant lift one hindleg. Feel for a slight cranial shift of the contralateral tub sacrale as the SIJ of the weight-bearing leg assumes close-packed position. Repeat with the other leg.

Movement during limb protraction, Stand on a box behind the horse (or next to the horse if you suspect he may kick). Palpating the tuber sacrale bilaterally, have an assistant lift one hind leg and stretch it forward. Feel for a slight caudal shift of the contralateral tub sacrale.

PASSIVE TESTING,Stand on a box or step next to the horse. Apply a slow, repetitive downwards force on the tuber coxae. Feel for reflex muscle guarding in response to the movement. A non-painful horse should allow a soft oscillation of the ilium. Compare to the other side Again, bear in mind that movement of the pelvis also causes movement in the lumbar spine and hip, so observe carefully.