Podotrochlear bursa endoscopy in the horse: a cadaver study.

Objectives: To evaluate podotrochlear bursa (navicular bursa) endoscopy as a diagnostic technique in horses and to correlate observations to radiographic and pathologic findings.

Study Design: Descriptive study.

Sample Population: Seventeen equine cadaver forelimbs.

Methods: Five standard radiographic views of the navicular region and a bursographic study with lateromedial and caudal tangential radiographic views were taken of each forelimb. Radiographic scoring of the navicular bone (0, excellent; 1, good; 2, fair; 3, poor) was performed using a previously reported technique. Endoscopic examination was performed using a 30 degrees wide-angle forward oblique-viewing, 4-mm outside diameter (OD), arthroscope. Four examiners using recorded videotapes made independent evaluations of bursal endoscopy. The specimens were then dissected and examined to verify radiographic and endoscopic findings.

Results: The distribution of radiographic scores (RS) were 0 (5 limbs), 1 (7), 2 (2), and 3 (3). Abnormal endoscopic findings (fibrillation of the deep digital flexor tendon, a defect in the navicular bone fibrocartilage, and synovial hyperplasia) were identified in 3 limbs (2 with an RS of 1, and 1 with an RS of 3). The endoscopic observations made in the two RS 1 bursae were not confirmed on gross examination, whereas they were in the RS 3 specimen, which also had the only abnormal bursogram. Evaluation of the bursa on the side ipsilateral to the arthroscope portal was difficult. Complications of the technique included inadvertent penetration of the distal interphalangeal joint and the digital sheath, and superficial scoring of the navicular bone fibrocartilage.

Conclusions: Podotrochlear bursa endoscopy is feasible and may be a useful technique in identifying early abnormalities associated with podotrochleosis.

Clinical Relevance: In horses with podotrochleosis, endoscopic examination of the podotrochlear bursa may improve identification of pathologic changes within the bursa.