This retrospective case series about tenoscopic surgery of the DFTS aimed to:
- describe the prevalence of lesions associated with lameness caused by non-septic DFTS tenosynovitis in a large population of German sports and pleasure horses;
- determine the sensitivity and specificity of diagnostic imaging techniques for identifying lesions within the DFTS with tenoscopic-diagnosis being the gold-standard;
- explore associations between tenoscopically-diagnosed lesions and signalment, purpose, and limb affected; and
- describe the outcome following DFTS tenoscopy with non-septic DFTS tenosynovitis in this population.
The study reviewed medical records of horses admitted for tenoscopic surgery of non-septic DFTS tenosynovitis between 2011 and 2020. Researchers obtained follow-up information via telephone contact. The study determined the sensitivity and specificity of ultrasonography and contrast tenography using tenoscopic diagnosis as gold standard. It used univariable analysis to explore associations between signalment, case history, and tenoscopic diagnosis.
Researchers retrieved medical records from 131 horses, of which 61 were warmbloods. Eight horses had bilateral disease. Six horses were presented for tenoscopy on two separate occasions (three for tenoscopy in the same limb, and three in a different limb). This amounted to a total of 145 limbs. The researchers most commonly diagnosed lesions in the deep (DDFT, n=55 limbs) and superficial (SDFT, n=55 limbs) digital flexor tendons. They detected manica flexoria (MF) lesions in 44 limbs and palmar/plantar annular ligament (PAL) constriction in 99 limbs. In 36 limbs, only one structure within the DFTS was injured. In 109 limbs, researchers noted a combination of lesions; the most common were the combination of a SDFT lesion with PAL constriction.
Researchers examined all affected limbs with diagnostic ultrasonography; they performed contrast tenography in 86 limbs. For diagnosis of MF and DDFT tears, tenography was more sensitive (89% (CI 65.4-95.2%); 72% (CI 46.4-89.3%) respectively) than specific (64% (CI 52.5-77.6%); 53% (CI 42.2-73.3%) respectively), whereas ultrasonography was more specific (92% (CI 84.5-96.3%); 92% (CI 83.6-96.0%) with lower sensitivity (64% (CI 47.7-77.2%); 54% (CI 39.5-67.9%). For SDFT lesions, ultrasonography was highly specific (94% (CI 86.9-97.9%) with lower sensitivity (66% (CI 51.3-77.4%).
The researchers obtained follow-up information after the first surgery for 118 horses (132 limbs). The results were as follows: 18/118 (15.3%) horses remained chronically lame; 40 (33.8%) performed at a reduced level; and 60 (50.8%) performed at the same or higher level following rehabilitation after tenoscopy. Horses with DDFT lesions had the poorest outcomes, with only 36.6% returning to the same or higher level of exercise.
Diagnostic imaging techniques were complimentary, contrast tenography was sensitive and ultrasonography was specific for the diagnosis of MF and DDFT lesions. Researchers identified more than one pathology in 75% of limbs. Following tenoscopic surgery, approximately half the cases were able to return to pre-injury level of exercise.