Tenosynovitis associated with longitudinal tears of the digital flexor tendons in horses: a report of 20 cases.

The paper describes a series of cases with longitudinal tears in the superficial or deep digital flexor tendons within the digital flexor tendon sheath. This appears to be a previously unreported condition. Twenty cases are described, one horse was affected bilaterally. Nineteen defects involved the deep digital flexor tendon and in 2 horses the manica flexoria of the superficial digital flexor tendon was torn. All affected horses were lame and there was marked distension of the digital flexor tendon sheaths. Ultrasonography revealed nonspecific signs of chronic tenosynovitis but not the cause. Diagnosis was established by tenoscopy in 9 cases and by open surgical exploration in the remainder. In 7 limbs, the deep digital flexor tendon lesions were treated by removal of the torn fibrils under tenoscopic control. In the remaining cases they were removed and the defects were repaired with absorbable suture material. Wound closure in all open cases included repair of the palmar/plantar annular ligament. Eleven horses became sound and returned to work, 3 improved but were lame on returning to work and 2 horses did not improve following treatment. At the time of reporting, 4 horses are sound and in controlled ascending exercise regimes. It is concluded that longitudinal tears of the digital flexor tendons should be considered in the differential diagnosis of tenosynovitis of the digital flexor tendon sheath. The results presented suggest that accurate diagnosis and specific treatment justify surgical investigation.