Equine Septic Tenosynovitis Study Guide

Overview and Clinical Importance

Septic tenosynovitis is an infection of tendon sheaths that represents a serious orthopedic emergency in horses. The condition occurs when bacteria invade the synovial structures surrounding tendons, most commonly affecting the digital flexor tendon sheath (DFTS) in the fetlock region. Due to the superficial nature of synovial structures in the equine distal limb and limited soft tissue coverage, penetrating wounds frequently result in bacterial contamination of these structures.

The clinical significance of septic tenosynovitis cannot be overstated. Without prompt recognition and aggressive treatment, infection leads to severe inflammation, fibrous adhesion formation, tendon damage, and potentially life-threatening complications including laminitis in the contralateral limb. Studies indicate that only approximately 50% of horses treated for septic digital tenosynovitis return to their previous level of athletic function, making early diagnosis and intervention critical.

Relevant Anatomy

Digital Flexor Tendon Sheath (DFTS)

The digital flexor tendon sheath is a synovial structure that extends from the distal third of the metacarpus/metatarsus to the level of the middle phalanx. It encompasses both the superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT) as they pass around the palmar/plantar aspect of the fetlock joint.