Bilateral hindlimb superficial digital flexor tendinopathy in a sports horse.

Bilateral hindlimb superficial digital flexor tendinopathy (SDFT) is rare in sports horses. This case report describes the diagnosis, treatment, and successful recovery of a 16-year-old Irish sports horse with this condition following an eventing competition.

Background

• Superficial digital flexor tendinopathy commonly causes forelimb lameness in Thoroughbred racehorses and other sports horses.
• Occurrence in the hindlimbs is uncommon with few reported cases.
• The SDFT is a critical tendon supporting locomotion and absorbing impact forces during movement.

Case Presentation

• The subject was a 16-year-old Irish sports horse gelding.
• Presented with bilateral swelling around the plantar metatarsal (back of the lower leg near the hock) region of both hindlimbs.
• Severe bilateral hindlimb lameness was noted, visible even at a walk.
• Lameness started following a cross-country phase in an eventing competition, implicating sport-related injury.

Diagnosis

• Clinical suspicion was directed towards a superficial digital flexor tendon injury due to presentation and location.
• Ultrasonographic examination confirmed the diagnosis by revealing extensive core lesions in the SDFTs of both hindlimbs.
• Ultrasound imaging is a valuable tool enabling visualization of tendon fiber damage and lesion extent.

Treatment

• The horse received ultrasound-guided intralesional injections with autologous bone marrow aspirate concentrate (BMAC).
• BMAC provides stem cells and growth factors that facilitate tissue repair and regeneration.
• Treatment included a controlled exercise program, essential for gradual tendon healing and regaining strength without overstressing tissues.

Outcome and Follow-up

• The rehabilitation period lasted eight months, after which the horse was able to resume showjumping activities.
• Long-term follow-up over 44 months showed no recurrence of the SDFT lesions or lameness.
• This outcome indicates successful recovery and functionality restoration of the affected tendons.

Significance

• This case is reportedly the first description of bilateral hindlimb SDF tendinopathy in the metatarsal region of a sports horse.
• It highlights the possibility of such injuries occurring beyond commonly affected forelimb tendons.
• Demonstrates the effectiveness of ultrasound-guided BMAC treatment combined with rehabilitation in managing tendon injuries.
• Provides valuable clinical insights for veterinarians managing unusual cases of hindlimb tendon injuries in performance horses.