Abstract: Pathology of the digital flexor tendon sheath is a significant cause of lameness in the horse. Imaging is important to identify lesions and inform on prognosis prior to tenoscopic surgery. Objective: To use a large population to evaluate 1) the sensitivity and specificity of digital flexor tendon sheath (DFTS) contrast radiographs in diagnosing manica flexoria (MF) tears, deep digital flexor tendon (DDFT) tears and constriction of the palmar/plantar annular ligament (PAL) using novel criteria; 2) predisposition to pathology in signalment and limb affected. Methods: Multicentre retrospective cohort study. Methods: The medical records of 206 horses with lameness localised to the DFTS, contrast radiographs and subsequent tenoscopic surgery were reviewed. Breed and limb predispositions were evaluated for pathology of the DDFT, MF and PAL constriction. Contrast radiographs of the DFTS were reviewed by four masked operators and for each pathology the sensitivity, specificity and interobserver variability were calculated. Results: Contrast tenography was a sensitive test for MF tears (92% confidence interval [CI] 88.4-94.4%; specificity 56%, CI 51.1-61.1%) and specific for diagnosing DDFT tears (73%, CI 68.6-76.8%; sensitivity 54%, CI 47.8-60.2%) but had a lower sensitivity (71%, CI 65.1-75.9% ) and specificity (45%, CI 39.1-52.0%) for PAL constriction. It had good to substantial interobserver agreement for MF and DDFT tears (Krippendorff's alpha 0.68 and 0.46 respectively). Ponies (57%) and cobs (58%) were significantly more likely to be affected with MF tears (other breeds 20-39%, P = 0.003) and Thoroughbreds (50%), warmbloods (45%) and draught breeds (48%) were more likely to have DDFT tears (other breeds 22-34%, P = 0.01). MF tears and PAL constriction were overrepresented in the hindlimbs compared to DDFT tears in forelimbs. Conclusions: No standardisation of contrast radiographs was possible. The subjectivity of diagnosis of PAL constriction may also have led to bias. Radiographs were read as JPEGS reducing ability to manipulate images. Conclusions: Contrast radiography of the DFTS is accurate in the pre-operative diagnosis of DFTS pathologies. Different pathologies are overrepresented in certain breeds and limbs.
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The research article focuses on improving the diagnostic criteria for digital flexor tendon sheath pathology in horses using contrast tenography. It emphasizes on imaging’s role in identifying lesions and informing prognosis prior to surgery.
Research Methodology
The study is a multicentre retrospective cohort type, where researchers studied the records of 206 horses that showed lameness localized to the digital flexor tendon sheath.
These horses had undergone contrast radiographs and subsequent tenoscopic surgery.
The study aimed to determine: a) the sensitivity and specificity of these contrast radiographs in diagnosing three possibilities – manica flexoria (MF) tears, deep digital flexor tendon (DDFT) tears and constriction of the palmar/plantar annular ligament (PAL); b) the potential predisposition of certain horse breeds and limbs to such pathology.
The contrast radiographs were assessed by four examiners who were unaware of the patients’ identities. The researchers also tested for interobserver variability, a measure of agreement or consensus among different observers.
Key Findings
Contrast tenography appeared to be a reliable way to detect MF tears, with high sensitivity but relatively low specificity.
It has been found specific for diagnosing DDFT tears, but has a lower sensitivity.
The method performed relatively poorly when diagnosing PAL constriction both in terms of sensitivity and specificity.
The research showed substantial agreement among different examiners for MF and DDFT tears.
It was found that ponies and cobs were more likely to be affected with MF tears while Thoroughbreds, Warmbloods, and draught breeds were more prone to DDFT tears.
MF tears and PAL constrictions were more commonly found in hindlimbs as compared to DDFT tears which were more likely in forelimbs.
Study Limitations
The study was unable to standardize contrast radiographs due to varying conditions of the imaging.
The diagnosis of PAL constriction was somewhat subjective, which may have introduced some bias into the results.
The images were viewed as JPEGs, which limited the ability to manipulate the images for detailed examination.
Conclusion
The use of contrast tenography for the pre-operative diagnosis of DFTS pathologies in horses appears to be accurate.
The study also reveals that different horse breeds and particular limbs are more prone to specific types of DFTS pathologies.
Cite This Article
APA
Kent AV, Chesworth MJ, Wells G, Gerdes C, Bladon BM, Smith RKW, Fiske-Jackson AR.
(2019).
Improved diagnostic criteria for digital flexor tendon sheath pathology using contrast tenography.
Equine Vet J, 52(2), 205-212.
https://doi.org/10.1111/evj.13166
Kummerle J.M, Theis F, Smith R.K.W. Diagnosis and management of tendon and ligament disorders. In: Equine Surgery, 5th edn., Eds: J.A. Auer and J.A. Stick, Elsevier, St Louis, Missouri. pp 1411-1444.
Perneger T.V. What’s wrong with Bonferroni adjustments. Brit. Med. J. 316, 1236-1238.