NAVLE Equine Surgery and Lameness Questions and Answers — Questions and Answers
Question 1: A 10-year-old Quarter Horse presents with a chronic, intermittent, bilateral forelimb lameness that worsens on hard surfaces. The horse points the affected feet and shows a shortened cranial phase of the stride. Hoof tester application across the heels elicits a painful response. A palmar digital nerve block significantly improves the lameness. Which of the following is the most likely diagnosis?
- Laminitis
- Navicular syndrome (Correct answer)
- Coffin joint septic arthritis
- Sole abscess
Correct answer: Navicular syndrome
Navicular syndrome is a chronic degenerative condition affecting the navicular bone and associated soft tissue structures in the heel of the foot. The clinical signs described—chronic bilateral forelimb lameness, pointing, pain on hoof testers over the heel, and improvement with a palmar digital nerve block—are all classic indicators of this condition. While other conditions can cause heel pain, the chronicity and bilateral nature strongly suggest navicular syndrome.
Question 2: A 4-week-old foal presents with a carpal valgus deformity of the right forelimb. The deviation is moderate and has not improved with stall rest and corrective hoof trimming. What is the most appropriate next step in managing this case to achieve a successful outcome?
- Continue conservative management as the growth plates will close soon.
- Perform transphyseal bridging on the medial aspect of the distal radius.
- Perform periosteal stripping on the medial aspect of the distal radius. (Correct answer)
- Recommend euthanasia due to a poor prognosis for athletic function.
Correct answer: Perform periosteal stripping on the medial aspect of the distal radius.
For a moderate carpal valgus (knock-kneed) deformity in a 4- to 6-week-old foal that is not responding to conservative therapy, periosteal stripping (also called a hemicircumferential periosteal transection and elevation) on the concave side (medial aspect) of the limb is the appropriate surgical intervention. This procedure is thought to accelerate growth on the slower-growing side of the physis. Transphyseal bridging is used on the convex (lateral) side to slow growth and is typically reserved for more severe deformities or older foals. Continuing conservative management is inappropriate as the optimal window for surgical correction is during rapid growth.
Question 3: A 12-year-old Thoroughbred mare undergoes an emergency exploratory celiotomy for a large colon volvulus. Which of the following is the most common post-operative complication that can significantly impact morbidity and mortality in the immediate post-surgical period?
- Incisional infection
- Laminitis
- Adhesion formation
- Post-operative ileus (POI) (Correct answer)
Correct answer: Post-operative ileus (POI)
Post-operative ileus (POI), characterized by a lack of normal intestinal motility, is a very common and serious complication following equine colic surgery, particularly after procedures involving the small intestine or significant large colon manipulation. It can lead to gastric reflux, pain, and endotoxemia, and is a leading cause of post-operative death or euthanasia. While incisional infections, laminitis, and adhesions are also significant complications, POI is a more immediate and frequent life-threatening concern in the first few days post-surgery.
Question 4: A horse presents with a sudden onset of severe, non-weight bearing lameness of the left hindlimb. The tarsocrural joint is markedly distended, warm, and painful on palpation. Arthrocentesis reveals a turbid, yellow synovial fluid with a total protein of 5.2 g/dL and a nucleated cell count of 95,000 cells/µL, with 92% neutrophils. What is the most critical and effective treatment for this condition?
- Systemic antibiotics and stall rest alone
- Intra-articular corticosteroids and bandaging
- Joint lavage and systemic broad-spectrum antibiotics (Correct answer)
- Application of a cast and long-term NSAID administration
Correct answer: Joint lavage and systemic broad-spectrum antibiotics
The clinical signs and synovial fluid analysis are indicative of septic arthritis, a true medical emergency in horses. The cornerstone of successful treatment is aggressive and immediate intervention to eliminate the infection and remove inflammatory mediators from the joint. This is best accomplished through joint lavage (flushing the joint with large volumes of sterile fluid), often performed arthroscopically, combined with systemic broad-spectrum antibiotics. Administering only systemic antibiotics is insufficient, and intra-articular corticosteroids are contraindicated in the face of infection.
Question 5: A 6-year-old horse is presented with a history of spontaneous, severe epistaxis (nosebleed) from the right nostril. Endoscopic examination reveals a large, diphtheritic membrane on the dorsal aspect of the right guttural pouch, overlying the internal carotid artery. What is the most definitive treatment to prevent a fatal hemorrhage in this horse?
- Long-term systemic antifungal therapy
- Transarterial coil embolization of the affected artery (Correct answer)
- Daily lavage of the guttural pouch with povidone-iodine
- Surgical removal of the fungal plaque
Correct answer: Transarterial coil embolization of the affected artery
Guttural pouch mycosis with erosion of a major artery, such as the internal carotid, is a life-threatening emergency due to the risk of fatal hemorrhage. The most effective and definitive treatment to prevent bleeding is to occlude blood flow to the affected arterial segment. Transarterial coil embolization is the preferred method to achieve this. While medical management with antifungal drugs is part of the overall treatment to resolve the infection, it does not address the immediate risk of catastrophic bleeding.
Question 6: Which of the following describes the classic gait abnormality associated with Australian stringhalt?
- A short, choppy stride in the forelimbs, often described as 'walking on eggshells'.
- A spastic, involuntary hyperflexion of one or both hindlimbs during movement. (Correct answer)
- Ataxia and paresis, most pronounced in the hindlimbs, that worsens with circling.
- A dragging of the toes of the hind feet, resulting in squared-off hoof wear.
Correct answer: A spastic, involuntary hyperflexion of one or both hindlimbs during movement.
Stringhalt is a neuromuscular condition characterized by an involuntary, spasmodic, and exaggerated upward flexion of one or both hindlimbs during the protraction phase of the stride. Australian stringhalt is a specific form, often seen in outbreaks, associated with the ingestion of toxic plants like Hypochaeris radicata (flatweed). The gait is often described as a jerking or snapping of the hindlimb up toward the abdomen.
NAVLE Equine Surgery and Lameness Questions and Answers
A 10-year-old Quarter Horse presents with a chronic, intermittent, bilateral forelimb lameness that worsens on hard surfaces.
The horse points the affected feet and shows a shortened cranial phase of the stride.
Hoof tester application across the heels elicits a painful response.
A palmar digital nerve block significantly improves the lameness.
Which of the following is the most likely diagnosis?