RESUMO
BACKGROUND: Focal hyperintense lesions within the navicular bursa emanating from the dorsal border of the deep digital flexor tendon (DDFT) can be recognised on T1-weighted magnetic resonance images (MRI) and have been attributed to lameness in horses. Removal of these lesions, also referred to as synovial masses, by navicular bursoscopy is currently recommended. OBJECTIVES: To investigate the correlation between MRI and navicular bursoscopic findings. It is hypothesised that the prognosis following surgery is proportional to the size of the DDFT lesion. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Horses undergoing standing low-field MRI and navicular bursoscopy with >1 year follow-up were included. A grading system was developed to classify the size of synovial mass(es) and lesion(s) of the DDFT on MRI and at surgery. Generalised estimating equations were used to evaluate the association between MRI findings and surgery and between outcome and severity of the tendon injury. RESULTS: Fifty-nine horses presenting over a 15-year period (2006-2021) fulfilled inclusion criteria. Ninety navicular bursae were examined both on MRI and endoscopically. There was strong correlation between the size of synovial masses and tendon lesions on MRI and bursoscopy (p < 0.001, OR: 25.61, 95% CI 8.71-75.29 and p < 0.001, OR: 7.34, 95% CI 2.70-19.92, respectively). Size of tendon lesion and synovial mass had no impact on prognosis (p = 0.3, OR: 1, 95% CI 1-1 and p = 0.1, OR: 1, 95% CI 1-1, respectively), which was guarded (30.5% return to previous level of exercise). MAIN LIMITATIONS: Performance data for conservatively treated horses with MRI-detected synovial masses was not considered, nor was the effect of navicular bursal effusion. Horses were not randomly assigned to treatment protocols. CONCLUSION: There is good correlation between MRI and bursoscopic findings of DDFT lesions and synovial masses within the navicular bursa, with no false positives. Size of the synovial masses and DDFT lesions does not influence prognosis following navicular bursoscopy.
RESUMO
OBJECTIVE: To compare the outcome following conservative vs surgical management of sports horses with a diagnosis of subchondral bone trauma of the proximal aspect of the proximal phalanx (PP) by low-field MRI. STUDY DESIGN: Retrospective case series. ANIMALS: Twenty-one mature sports horses with evidence of high water signal within the proximal sagittal groove of the PP according to low-field MRI of the fetlock, with no definitive radiographic evidence of fracture. METHODS: Medical records (2010-2017) of horses admitted to 2 referral hospitals were reviewed. Historical, clinical, radiographic, and MRI findings and treatment choice were recorded. Conservative management consisted of confinement to a stall followed by gradual reintroduction to exercise. Surgical management consisted of cortical screw fixation across the proximal aspect of the PP. Long-term outcome was determined by telephone questionnaire or by clinical records review. Fisher's exact test was used to compare outcome between the 2 treatment groups. RESULTS: Follow-up was available in 17 of 21 horses in the study, including 8 horses treated conservatively and 9 treated surgically. No difference in outcome was detected in this study; 4 of 8 horses were sound after conservative management, and 5 of 9 horses were sound after surgery (P > .99). CONCLUSION: Approximately half of the horses that had a diagnosis of osseous trauma within the proximal aspect of PP returned to athletic activity, regardless of conservative or surgical management. CLINICAL SIGNIFICANCE: The prognosis for return to athletic functions in horses with osseous trauma within the proximal aspect of the PP is guarded.
