NAVLE Equine Surgery and Lameness 6

Question 1

A 7-year-old Warmblood show jumper presents with intermittent right forelimb lameness that worsens after flexion of the distal limb. Radiographs reveal subchondral bone cysts in the medial femoral condyle. Intra-articular analgesia of the femoropatellar joint provides 70% improvement. Which treatment approach has demonstrated the highest long-term success rate for return to athletic function in horses with large (>15 mm) medial femoral condyle cysts?

Accepted Answer

Arthroscopic debridement with intralesional corticosteroid injection

Answer

Arthroscopic debridement combined with intralesional corticosteroid injection (typically triamcinolone acetonide) into the cyst lining is the gold-standard surgical treatment for large medial femoral condyle cysts. This technique disrupts the fibrous cyst lining that maintains the cystic cavity and delivers high local concentrations of corticosteroid, which reduces the inflammatory mediators driving bone resorption. Studies show return-to-athletic-function rates of 60–75% with this approach, superior to conservative management or bone grafting alone for cysts >15 mm.

Question 2

During arthroscopic surgery of the equine tarsocrural joint, the surgeon inadvertently penetrates the medial plantar pouch and instrument access is compromised. Which anatomical landmark best describes the communication (or lack thereof) between the tarsocrural joint and the proximal intertarsal joint in most horses, and what is its clinical implication for analgesia?

Accepted Answer

No consistent communication exists; analgesia of the tarsocrural joint does not reliably desensitize the proximal intertarsal joint

Answer

The tarsocrural joint and proximal intertarsal joint do NOT consistently communicate in adult horses. While communication may occasionally be present, it cannot be relied upon clinically. This is why diagnostic analgesia must be performed separately for each joint when localizing lameness to the hock region. Failure to appreciate this anatomy leads to misinterpretation of nerve block results, particularly when differentiating tarsocrural pathology from bone spavin (distal intertarsal/tarsometatarsal involvement).

Question 3

A 4-year-old Thoroughbred racehorse presents with acute onset severe (grade 4/5) right forelimb lameness following a morning workout. Ultrasonography reveals a complete core lesion of the superficial digital flexor tendon (SDFT) at the mid-metacarpal level with a cross-sectional area 40% greater than the contralateral limb. The owner inquires about intralesional platelet-rich plasma (PRP) therapy. Which statement most accurately reflects current evidence-based understanding of PRP in equine SDFT repair?

Accepted Answer

PRP has not consistently demonstrated improved long-term outcomes over controlled exercise rehabilitation alone in controlled trials

Answer

Despite widespread clinical use, PRP has not consistently shown superior long-term outcomes compared to controlled exercise rehabilitation alone in rigorous controlled clinical trials for equine SDFT injuries. While PRP contains growth factors (TGF-β, PDGF, IGF-1) that theoretically promote tendon healing, prospective blinded studies in racehorses have failed to demonstrate significant differences in re-injury rates or return-to-sport timelines. The evidence base remains limited by small sample sizes and methodological heterogeneity, making controlled exercise rehabilitation the only consistently evidence-supported intervention.

Question 4

A 12-year-old Quarter Horse cutting horse presents with chronic bilateral hindlimb stiffness and a 'rope-walking' gait. On rectal palpation, crepitus is noted over the lumbosacral region. Standing radiographs are non-diagnostic. Scintigraphy reveals focal increased radiopharmaceutical uptake at L5-S1. Nuclear scintigraphy-guided infiltration of the lumbosacral space with corticosteroid provides marked temporary improvement. What is the most appropriate long-term management strategy if conservative therapy fails after two injection cycles?

Accepted Answer

Extracorporeal shock wave therapy (ESWT) targeted to the lumbosacral facet joints under ultrasound guidance

Answer

For horses with confirmed lumbosacral pathology refractory to intra-articular corticosteroid, extracorporeal shock wave therapy (ESWT) targeted under ultrasound guidance to the lumbosacral facet articulations is a validated next-line intervention. ESWT delivers acoustic energy that modulates pain via nerve fiber hyperpolarization and stimulates local tissue remodeling. It is minimally invasive, can be repeated, and has demonstrated efficacy in peer-reviewed studies for horses with thoracolumbar and lumbosacral pain. Sacroiliac arthrodesis addresses the SI joint but not lumbosacral facets, and chemical neurolysis is not an accepted equine technique for this indication.

Question 5

An 8-year-old Arabian endurance horse undergoes elective arthroscopy of the left carpal joints. During closure, the surgeon notes excessive hemorrhage from the dorsal aspect of the antebrachiocarpal joint. Which vessel, if lacerated during carpal arthroscopy via the standard dorsolateral or dorsomedial portals, is the most common source of significant intraoperative hemorrhage and what is the recommended immediate management?

Accepted Answer

Dorsal carpal branch of the radial artery; controlled lavage with epinephrine-containing saline and direct cautery

Answer

The dorsal carpal branch of the radial artery crosses the dorsal aspect of the carpus and is at risk during portal placement or instrument manipulation in equine carpal arthroscopy. Significant hemorrhage from arterial origin can obscure visualization and complicate closure. Initial management includes copious joint lavage to clear the field, followed by direct electrocautery of the vessel if it can be visualized arthroscopically. Epinephrine in irrigation fluid is used as an adjunct to promote vasoconstriction. The cephalic and accessory cephalic veins are also at risk but produce lower-pressure venous bleeding more readily managed with pressure alone.

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE Equine Surgery and Lameness 6