EQUINE | Abstracts
Improved diagnostic criteria for digital flexor tendon
sheath pathology using contrast tenography
A. V. Kent, M. J. Chesworth, G. Wells, C. Gerdes, B. M. Bladon, R. K. W. Smith, A. R. Fiske‐Jackson
Background
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.
Objectives
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.
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.
Main limitations
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.
Study design
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.
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.
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
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