Description
The increased use of both high-field and low-field magnetic resonance imaging (MRI) in equine practice over the last decade has allowed equine clinicians to demonstrate that injuries of the deep digital flexor tendon (DDFT) are a common cause of foot lameness in the horse.
Four different types of lesion are recognised in the distal portion of the DDFT, namely core lesions, dorsal fraying and fibrillation, partial and complete parasagittal splits and insertional lesions.
Lesions of the DDFT occur most commonly at the level of the navicular bone and proximal aspect of the navicular bursa, less commonly at the insertion of the DDFT to the distal phalanx and least commonly at the level of the proximal interphalangeal joint and proximal phalanx. Lesions may be the primary cause of lameness although they commonly occur in conjunction with degenerative changes or injuries to other structures in the foot.
Generally it has been considered that the most important factor in the treatment of injuries of the DDFT in the foot is the need for prolonged rest. Rest for core lesions and parasagittal splits should consist of stall or small pen confinement for at least 6–12 months with low-grade maintenance exercise consisting of daily in-hand walking for up to 60 min on a slowly ascending regime. Longer lay off may be required for more severe lesions. However, retrospective studies of horses with primary digital DDFT lesions treated conservatively with rest for at least 6 months have been discouraging with only about 25-30% returning to their previous level of athletic function.
Learning Objectives
- Understand the normal appearance of the deep digital flexor tendon on MRI scans
- Types of lesions seen in the distal portion of the deep digital flexor tendon on MRI scans
- Understand what different types of MR sequences highlight
- Review the evidence for conservative and interventional treatments for distal deep digital flexor tendon injuries
- Review the role of surgery for treatment of distal deep digital flexor tendon injuries
