NAVLE Equine Lameness and Diagnostics 5 — Questions and Answers
Question 1: A horse with forelimb lameness has a positive response to hoof testers over the medial heel region. After palmar digital nerve block the lameness is only partially improved. The MOST appropriate next step is:
- Repeat the palmar digital block with a higher volume
- Block the navicular bursa directly
- Perform an intra-articular coffin joint block (Correct answer)
- Apply a bar shoe and reassess in 6 weeks
Correct answer: Perform an intra-articular coffin joint block
When a palmar digital block provides only partial improvement, an intra-articular coffin joint block helps determine whether the DIP joint is contributing to the residual lameness.
Question 2: Equine degenerative joint disease of the proximal interphalangeal joint (high ringbone) is BEST confirmed with:
- Ultrasonography of the pastern
- Lateromedial and dorsopalmar radiographs of the pastern (Correct answer)
- Thermography of the lower limb
- Intra-articular anesthesia of the coffin joint
Correct answer: Lateromedial and dorsopalmar radiographs of the pastern
High ringbone (periarticular or articular osteoarthritis of the PIP joint) is diagnosed radiographically, with lateromedial and dorsopalmar views demonstrating periarticular osteophytes and joint space narrowing.
Question 3: Which perineural block is required to desensitize the entire foot including the coronary band?
- Palmar digital nerve block
- Low 4-point nerve block (palmar metacarpal + palmar digital)
- Abaxial sesamoid nerve block (Correct answer)
- High palmar (high 2-point) nerve block
Correct answer: Abaxial sesamoid nerve block
An abaxial sesamoid nerve block desensitizes the entire foot including the coronary band by blocking the medial and lateral palmar digital nerves at the level of the proximal sesamoid bones.
Question 4: A 5-year-old event horse has hindlimb lameness localized to the sacroiliac region by positive pressure on the tuber sacrale and a positive response to gluteal muscle palpation. The BEST imaging modality for confirming sacroiliac pathology is:
- Radiography of the pelvis
- Nuclear scintigraphy or ultrasound of the sacroiliac joint (Correct answer)
- CT scan of the hindlimb
- Radiography of the lumbar spine only
Correct answer: Nuclear scintigraphy or ultrasound of the sacroiliac joint
The sacroiliac joint is difficult to image radiographically due to its deep location; nuclear scintigraphy and transrectal or transcutaneous ultrasound are the most effective modalities for evaluating this region.
Question 5: Intra-articular injection of which substance is used as a visco-supplementation therapy to improve synovial fluid quality in horses with joint disease?
- Methylprednisolone acetate
- Hyaluronic acid (sodium hyaluronate) (Correct answer)
- Polysulfated glycosaminoglycan (Adequan)
- Platelet-rich plasma (PRP)
Correct answer: Hyaluronic acid (sodium hyaluronate)
Sodium hyaluronate (hyaluronic acid) is injected intra-articularly to restore viscosity and lubrication of synovial fluid, acting as visco-supplementation in arthritic joints.
Question 6: A warmblood dressage horse presents with bilateral hindlimb toe-dragging and a shuffling gait. Neurological examination reveals hindlimb ataxia. The MOST important differential diagnosis to rule out first is:
- Bilateral bone spavin
- Cervical vertebral stenotic myelopathy (Wobbler syndrome) (Correct answer)
- Bilateral upward fixation of the patella
- Bilateral proximal suspensory desmitis
Correct answer: Cervical vertebral stenotic myelopathy (Wobbler syndrome)
Cervical vertebral stenotic myelopathy (Wobbler syndrome) causes compressive spinal cord disease manifesting as hindlimb ataxia and toe-dragging and must be differentiated from primary joint lameness.
Question 7: During a pre-purchase examination, you find a 4/5 grade on the AAEP lameness scale in the right forelimb. According to the AAEP scale, this means the horse:
- Is lame only under certain circumstances (hard surface, circles)
- Consistently lame but weight-bearing at the walk and trot
- Lame at the walk, occasionally non-weight-bearing (Correct answer)
- Is non-weight-bearing at all times
Correct answer: Lame at the walk, occasionally non-weight-bearing
AAEP grade 4/5 describes a horse that is lame at the walk and consistently lame at the trot, occasionally non-weight-bearing; grade 5 is non-weight-bearing at all times.
NAVLE Equine Lameness and Diagnostics 5
A horse with forelimb lameness has a positive response to hoof testers over the medial heel region.
After palmar digital nerve block the lameness is only partially improved.
The MOST appropriate next step is: