Nonseptic tenosynovitis of the digital flexor tendon sheath caused by longitudinal tears in the digital flexor tendons: A retrospective study of 135 tenoscopic procedures

Reasons for performing study: Longitudinal tears (LTs) of the digital flexor tendons are an important cause of chronic tenosynovitis of the digital flexor tendon sheath (DFTS). The origin of those marginal tears is not yet fully understood. The long-term outcome after medical and surgical treatment is guarded. Objectives: To determine the prevalence of LTs of the digital flexor tendons in a large population of horses undergoing diagnostic tenoscopy of the DFTS and to assess the outcome of surgical treatment and the factors influencing the outcome. Methods: Medical records of 130 horses with chronic tenosynovitis of the DFTS that had tenoscopic surgery between 1999 and 2009 were evaluated. One hundred and thirty-five DFTSs were examined. LTs were diagnosed in 104 DFTSs in 101 horses and long-term follow-up was obtained. Results: Seventy-eight percent of the horses with a nonseptic tenosynovitis of the DFTS had a LT. Preoperative ultrasonographic examination diagnosed tears in 76% of the cases. In showjumpers forelimbs were more frequently affected than hindlimbs (88 vs. 12%), with the right front having a higher incidence of injury than the left front (76 vs. 24%). Seventy-nine percent of the tears involved the deep digital flexor tendon (DDFT) and 87% were located on the lateral tendon border. Thirty-seven horses (38%) returned to an equal or higher level of work. The use of a radiofrequency probe (coblation) was associated with a lower level of performance and decreased the cosmetic end result. Persistence of marked post operative distension of the DFTS carried a poor prognosis for return to previous level of work. Conclusions and potential relevance: A guarded prognosis for future soundness should be given to horses presented for treatment of LTs of the digital flexor tendons. The use of coblation wands had a negative effect on the final outcome.