Magnetic Resonance Imaging Features of Oblique and Straight Distal Sesamoidean Desmitis in 27 Horses

Abstract

Injury to the oblique and straight distal sesamoidean ligaments is becoming recognized as a more common cause of lameness in horses than was previously thought. The purpose of this study was to review the magnetic resonance (MR) imaging findings of 27 horses affected with desmitis of the oblique and/or straight distal sesamoidean ligament and determine long-term prognosis for horses with this diagnosis. Imaging was performed with horses in right lateral recumbency in a high-field 1 T magnet. All horses had lameness localized to the digit or metacarpophalangeal/metatarsophalangeal joint region with diagnostic local anesthetic blocks. Ten horses had forelimb lameness and 17 horses had hind limb lameness. MR imaging revealed abnormalities in the oblique distal sesamoidean ligaments in 18 horses, in the straight distal sesamoidean ligament in three horses, and in both the oblique and straight distal sesamoidean ligament in six horses. Treatment consisted of a 6-month rest and rehabilitation program in all horses. The digital flexor tendon sheath was injected with methylprednisolone acetate and hyaluronic acid in 22 horses to decrease inflammation in the injured ligaments before starting the rest and rehabilitation program. Two horses had ligament splitting performed, one in the oblique distal sesamoidean ligament and one in the straight distal sesamoidean ligament. MR imaging is an effective method for diagnosing injury to the oblique and straight distal sesamoidean ligaments in horses. Treatment, primarily a 6-month rest and rehabilitation program, allowed 76% of the horses to successfully resume performance.

Evaluation of experimentally induced injury to the superficial digital flexor tendon in horses by use of low-field magnetic resonance imaging and ultrasonography

“…9 Several studies 6,9,11 have been conducted to compare results for ultrasonography and MRI of tendon with histologic characteristics of the tissue. In contrast, a more recent study 12 revealed that MRI was the better imaging modality for the diagnosis of desmitis in horses in which chronic scar tissue was present; chronic scar tissue is a pathological condition that is difficult to detect via ultrasonography. In 1 study, 6 the investigators concluded that there was no clear benefit of MRI over real-time ultrasonography for the detection of tendon lesions in horses.…”

“…In horses, MRI is now considered the criterion-referenced standard for detection of injuries in tendons 6,9 and ligaments. [10][11][12] In horses, MRI provides a promising alternative imaging modality to ultrasonography for the evaluation of pathological changes in tendons. The fibrous nature and low water content of equine tendons result in a low signal intensity in the primary diagnostic MRI sequences.…”

Precision of ultrasonographic measurements of the equine suspensory apparatus

“…Recently, magnetic resonance imaging studies confirmed that lesions of the DSL are an important cause of lameness localised to the pastern area (Sampson et al 2007, Smith et al 2008a). …”

Comparison of basilar and axial sesamoidean approaches for digital flexor tendon sheath synoviocentesis and injection in horses

“…[2][3][4] Historically, collection of synovial fluid from the DFTS or injection into the structure has been difficult if little or no effusion is present. [2][3][4] Historically, collection of synovial fluid from the DFTS or injection into the structure has been difficult if little or no effusion is present.…”

“…3,9,10 The purposes of the study reported here were to define a method for the BSA to the proximal collateral pouch of the DFTS and to compare it to the ASA 6 for DFTS synoviocentesis and injection in standing horses. Clinically, this approach has been used in standing and recumbent horses for administration of local anesthetic or medication and as a site for gaining access for lavage and tenoscopy.…”