Lameness in 46 horses associated with deep digital flexor tendonitis in the digit: diagnosis confirmed with magnetic resonance imaging

Abstract

Summary Reasons for performing study: The differential diagnosis of foot pain has long proved difficult and the use of magnetic resonance imaging (MRI) offers the opportunity to further the clinical understanding of the subject. Objectives: To determine the incidence of deep digital flexor tendon (DDFT) injuries in a series of 75 horses with lameness associated with pain localised to the digit, with no significant detectable radiographic or ultrasonographic abnormalities, using MRI; and to describe a variety of lesion types and relate DDF tendonitis with anamnesis, clinical features, response to local analgesic techniques and nuclear scintigraphic and ultrasonographic findings. Methods: All horses undergoing MRI of the front feet between January 2001 and October 2002 were reviewed and those with DDFT injuries categorised according to lesion type; horses with primary tendonitis (Group I) and those with concurrent abnormalities of the navicularbone considered to be an important component of the lameness (Group II). The response to perineural analgesia of the palmar digital nerves and palmar (abaxial sesamoid) nerves, intra‐articular analgesia of the distal interphalangeal (DIP) joint and analgesia of the navicularbursa were reviewed. The result of ultrasonography of the pastern and foot was recorded. Lateral, dorsal and solar pool and bone phase nuclear scintigraphic images were assessed subjectively and objectively using region of interest (ROI) analysis. Results: Forty‐six (61%) of 75 horses examined using MRI had lesions of the DDFT considered to be a major contributor to lameness. Thirty‐two horses (43%) had primary DDFT injuries and 14 (19%) a combination of DDF tendonitis and navicular bone pathology. Lesions involved the insertional region of the tendon alone (n = 3), were proximal to the navicular bone (n = 23) or were at a combination of sites (n = 20). Lesion types included core lesions, focal and diffuse dorsal border lesions, sagittal plane splits, insertional injuries and lesions combined with other soft tissue injuries. Many horses had a combination of lesion types. Lameness was abolished by palmar digital analgesia in only 11 of 46 horses (24%). Twenty‐one of 31 horses (68%) in Group I showed >50% improvement in lameness afterintra‐articular analgesia of the DIP joint, whereas 11 of 12 horses (92%) in Group II had a positive response. Twelve of 18 horses (67%) in Group I had a positive response to analgesia of the navicular bursa. Nineteen horses had lesions of the DDFT extending proximal to the proximal interphalangeal joint seen using MRI, but these were identified ultrasonographically in only 2 horses. Scintigraphic abnormalities suggestive of DDFT injury were seen in 16 of 41 horses (41%), 8 in pool phase images and 8 in bone phase images. Conclusions and potential relevance: DDFT injuries are an important cause of lameness associated with pain arising from the digit in horses without detectable radiographic abnormalities. Lameness is not reliably improved by palmar digital analgesia, but may...

Ultrasonographic diagnosis of injuries to the deep digital flexor tendon and associated structures in the equine foot (suprasesamoidean area)

“…2008) and magnetic resonance imaging (MRI) (Denoix et al . 1993; Dyson et al . 2003a,b, 2005; Busoni et al .…”

“…size, shape, echogenicity and architecture (Denoix 1994b, 1996, 1998a). Each anatomical structure of the PTA must be examined carefully, as concurrent injuries of several components of the PTA are common (Denoix 1997; Dyson et al . 2003a,b, 2005, 2006; Schneider et al .…”

Understanding MRI reports: Finding the lesions on an MRI study to show your clients

“…If MRI is so fabulous, then why do we need so many images for just one study? Dorsal margin abrasions, dorsal margin tears, core lesions, and parasagittal splits have all been described in equine tendons [13][14][15]. In addition, certain sequences are preferred for identifying specific types of pathologic change [10,11].…”

Magnetic resonance imaging and foot lameness. Problem solved? Or do we know we know less now that we know more?

“…The shining example of the use of MRI is the increased understanding of the DDF tendon and its role in foot lameness. It is now well established that DDF tendonitis is an important cause of foot lameness . Deep digital flexor tendonitis is reported to account for lameness in 59% of horses undergoing MRI scans for foot lameness, and up to 73% of horses when combined with abnormalities of the navicular bone .…”