Contributors: Gareth Arthurs, Toby J Gemmill

 Species: Canine   |   Classification: Miscellaneous

Introduction

  • Lameness investigation in the dog should fully assess the patient to establish whether lameness is caused by orthopedic or neurological disease. Ultimate aim is localization of the source of lameness and formulation of a list of differential diagnoses with a view to proceeding with the most appropriate diagnostic tests / management options for the patient.
  • A thorough lameness examination comprises:
  • Orthopedic examination should be preceded by a thorough history taking, gait evaluation and full clinical examination.
  • History frequently gives valuable information with respect to the likely causes or etiology of the dog's lameness and the clinical examination may identify other conditions that the dog may be suffering from which may or may not be related to the cause of the lameness. In addition, findings from general physical examination may subsequently influence the dog's suitability for sedation, general anesthesia, or a particular treatment option.
  • Although the orthopedic examination is only one part of the diagnostic work-up of a dog that may be lame, exercise intolerant, collapsing, ataxic or recumbent, the orthopedic examination is vitally important as the results of the orthopedic examination primarily dictate the direction of further diagnostics and treatment options for the patient. When presented with a dog requiring lameness investigation, the following approach is recommended.

Signalment and history taking

  • The dog's signalment should be noted and a thorough history taken. The following areas should be covered, and with each question the influence on the dog's lameness should not be overlooked:
    • Is the dog otherwise well?
    • If not, what are the dog's medical problems?
    • Is the dog receiving any medication?
    • How long has the owner had the dog?
    • How long ago did the lameness start, and what age was the dog at the time?
    • Which limb(s) is the dog lame on? How is the owner sure it is the identified limb? What sign does the owner see?
    • Was the onset of lameness acute or insidious in onset?
    • If the lameness was acute in onset, can an inciting event be identified?
    • Does the severity of lameness vary?
    • If so, does the severity vary in response to rest, exercise, administration of drugs such as NSAIDs, or any other factor?
    • Has the dog previously had any treatment for the lameness? If so, what? Did it work?
    • Has the dog travelled overseas?
  • Although noting the dog's signalment and taking a thorough history is not expected to identify the cause of the dogs lameness, common conditions are common. Therefore being aware of the most likely cause of lameness for a given history and signalment may help to direct the orthopedic examination or further diagnostics, particularly if the initial lameness examination is inconclusive. As examples:
    • A 12 month old male entire German Shepherd Dog with intermittent bouts of lameness, lethargy, depression and pyrexia is most likely to be suffering from eosinophilic panosteitis Panosteitis.
    • A 7 month old Chocolate Labrador puppy with pelvic limb lameness Lameness: hindlimb - investigation that is worst when the dog gets up from lying down, improves somewhat as the day progresses and improves on NSAIDs but deteriorates with exercise is most likely suffering from hip dysplasia Hip: dysplasia.
    • A 12 month old Rottweiler with forelimb lameness Lameness: forelimb - investigation that has been gradually getting worse over the last 4 months is most likely to be suffering from elbow dysplasia Elbow: dysplasia.
    • A 7 month old Staffordshire Bull Terrier that has gone acutely lame on a pelvic limb after jumping from a relatively low height, eg off a chair is quite likely to have fractured the physes of its tibial tuberosity and/or tibial plateau.
    • A 4 year old Labrador with recent either insidious or acute onset pelvic limb lameness with no history of more chronic limb lameness is highly likely to be suffering from cranial cruciate ligament disease Stifle: cranial cruciate ligament disease.
    • A 9 year old Mastiff with severe forelimb lameness that was insidious in onset but has rapidly progressed over the last 3 weeks has a high chance of suffering from osteosarcoma of the proximal humerus or distal radius Osteosarcoma.

Lameness or gait assessment

  • The lameness / gait assessment Gait analysis can be divided into 2 parts that are performed in the following order:
    • 1. Start by observing the dog as it first presents in the consulting room. Watch the dog's behavior when sitting, standing and lying down and how it moves between these positions. The dog may not fully weight bear on one limb, may hold the limb at an abnormal angle or unusual position, or may frequently shift weight away or re-distribute weight from the affected limb. Doing this may help to identify which limb(s) are causing a problem; observations to make include:
      • Does the dog struggle to get up on a particular limb?
      • Does the dog stand with all its weight evenly on all 4 limbs?
      • Does the dog hold one limb up at any stage?
      • Are the digits spread evenly when weight bearing?
      • Do any of the limbs tremble?
      • Are the limbs symmetrical?
      • Does one limb appear malaligned?
      • Does the dog sit and lie normally or abnormally, eg with one limb stuck out to the side?
      • In short haired breeds, it may be possible to appreciate muscle atrophy visually.
    • 2. Gait observation is used to further clarify which limb(s) is/are affected and how severely. Take the dog to an area where a gait observation can be performed, ie the dog can be observed standing, walking and trotting. Availability of locations may limit the scope of the gait observation, but indoors a long wide corridor with a non-slip surface is best; outdoors a smooth flat private tarmac road works very well. Uneven ground and other locations where the dog cannot / will not walk straight and evenly should be avoided.
      • a. Observe the dog walking at 3 different paces; slow, normal and quick walking. Observing the gait at different speeds allow detection of subtle lameness that may only be visible at certain speeds. It may be necessary to watch the dog for some time until the dog becomes comfortable with its environment and settles into a relaxed moving pace from which the lameness can be appreciated. The dog should also be watched whilst turning in tight circles to the left and right. This can be useful to help identify neurological problems.
      • b. Trotting: this may require an extra assistant to trot the dog as not all owners are able to jog alongside their dog (for health or other reasons) - also a sufficiently long space is necessary.
      • c. Running: it is usually impossible to directly observe a dog running at full speed in the clinical setting because letting the dog off lead is usually impractical, and finding sufficient time and space to allow the dog to build up speed is not usually possible. If observing the dog running fast is an essential part of the examination (for example a lameness only visible at high speed), the owners can be asked to make a video of the dog running and to bring the video to the consultation.
    • Gait observation can be challenging and difficult. It is normally possible for owner and veterinary surgeon alike to correctly identify the affected limb when pelvic limb lameness is present. However, forelimb lameness can be much more challenging. Features to observe that indicate forelimb lameness, and help to identify the correct thoracic limb include:
      • Reduced weight bearing of the affected limb when standing - if subtle, the toes / webbing of the affected foot may not be spread as widely as the other side due to reduced weight bearing.
      • Head Nod: for thoracic limb lameness, the head goes down as the normal limb strikes the ground and the head goes up when the affected limb strikes the ground: down is sound.
      • It is easiest to assess thoracic limb lameness as the dog walks towards you, and to assess pelvic limb lameness as the dog walks away.

Perform a general physical examination

  • It is essential to perform a general physical examination as part of a lameness investigation. Assuming that the dog is cooperative and will allow it, the dog's eyes, ears, nose, head and mouth should be examined, mucous membranes and arterial pulses assessed, the thorax / heart / lungs should be auscultated with a stethoscope, the abdomen should be palpated and the dogs skin should be assessed. Temperature, pulse and respiration should be taken. The purpose of this examination is to assess the dog's overall health as other disease may have an impact on lameness; for example:
    • A dog with a cardiac / circulatory anomaly may not be suitable for a any or all sedation protocols.
    • A dog with skin disease / pyoderma Skin: deep pyoderma may not be suitable for elective orthopedic surgery.
    • A dog with a thoracic or abdominal mass may present with lameness due to periosteal new bone pain of hypertrophic (pulmonary) osteopathy or Maries disease of the distal limbs Hypertrophic osteopathy ; the mass could be detected on initial examination.
    • The presence of significant intercurrent disease may affect the overall prognosis for the patient and influence whether an owner elects to proceed with further investigations or treatment.

Orthopedic examination – methodology

  • The orthopedic examination is arguably the most informative and critical part of the lameness investigation. The preceding steps of establishing the dog's signalment, history, observations when standing and walking, and gait examination should identify the affected limb, and allow a provisional list of likely differential diagnosis to be compiled. The orthopedic examination then identifies which joints, bones, tendons or muscles are affected and which are not.
  • The purpose of the orthopedic examination is to thoroughly assess each part of the dog's limbs and spine, and to rule orthopedic or neurological disease in or out. This is done by performing a thorough physical orthopedic examination. Most dogs will allow a comprehensive orthopedic examination without analgesia or sedation but such examination may occasionally not be possible if the patient is too painful, nervous or aggressive. In these circumstances, chemical restraint using sedation Sedation / sedative protocols or general anesthesia General anesthesia: overview is necessary to complete the orthopedic examination but this will be less productive as the reliability of eliciting a pain response and thus localizing a source of lameness will be limited.
  • In fractious patients it can be useful to repeat the examination after administration of a light sedative such as an acepromazine Acepromazine maleate /butorphanol Butorphanol tartrate combination. This often allows the examination to be completed but the animal's pain responses are preserved, hence localization of the source of any discomfort is usually still possible.

Be methodical

  • The key to a successful orthopedic exam is to be methodical, systematic and thorough. Examine every limb carefully and rigorously. It is good to get into the habit of comparing left and right limbs for similarities and differences. The clinician should develop his or her own systematic approach with which they are comfortable and familiar, and that they can repeat easily and reliably without omitting anything. It may be helpful to use a tick-sheet as an aid memoir and easy method of recording clinical findings; this ensures that nothing is missed and everything is covered and recorded.

Order of examination

  • Examine the affected limb last. For example, when investigating thoracic limb lameness, the pelvic limbs are examined first, then the unaffected thoracic limb, and finally the affected thoracic limb. This prevents initial distraction by findings in the affected limb that could results in omitting or missing findings of the other limbs.

Positioning for examination

  • It is usually more comfortable for the dog, owner and veterinary surgeon if large dogs are examined on the floor, and small dogs on a table. The author normally positions dogs standing for pelvic limb examination and sitting for thoracic limb examination. Occasionally small dogs may prefer to be examined on the floor but this can be more awkward for the examiner. Other dogs may prefer to lie down - indeed it can be near impossible to do an orthopedic examination on a giant breed dog unless it is lying down. Regardless, the dog must be allowed to assume a position in which it is comfortable and co-operative, and the clinician may need to alter his/her approach to accommodate this. A suggested order to proceed is:
    • Start with the dog standing and facing away from you.
    • Assess the degree of weight bearing on each limb; ensuring the dog is standing evenly, and gently push on the palmar/plantar aspect of the foot just proximal to the stopper pad, with the edge of one or two fingers. The same gentle pressure is applied to each foot. It takes less pressure to push forwards the foot of the affected limb (due to reduced weight bearing) than the normal limbs - this test can help to identify the affected limb if this is otherwise challenging.
    • Palpate and compare the musculature of both thoracic limbs and then both pelvic limbs (dog must be standing for the latter), specifically assessing and comparing for muscle atrophy and asymmetry that would be associated with chronic lameness.
    • Perform a basic neurological examination on each limb, ie:
      • Assess conscious proprioception with the dog standing, eg knuckling and paper-slide tests (Jeffery 2001).
      • Gently assess deep pain and flexor withdrawal responses in each limb.
      • Assess the cervical, thoracic, lumbar and sacral spine for full range of movement and pain on deep palpation and manipulation. Deep palpation of the lumbosacral joint to check for pain that may indicate lumbosacral disease Lumbosacral joint: acquired disease.
      • Perform a tail lift test: the tail is lifted vertically (dorsally) upwards and pushed cranially. A normal dog should tolerate this well. This test is used to assess for lumbosacral disease: a positive pain response is associated with lumbosacral disease but a positive pain response may also be associated with a painful tail or conditions affecting the perineum such as anal furunculosis Perianal fistula.
      • If these basic neurological tests results are normal, further neurological examination is generally not indicated. However, if any of these neurological tests are abnormal, further more detailed neurological assessment is warranted - see neurological examination Neurological examination.
  • Following this, each limb is methodically examined in turn, starting with the unaffected limbs. The affected limb(s) is/are examined last.