Subtrochlear sclerosis evaluation for medial coronoid disease detection and dynamic distal ulnar ostectomy for reduction of disease progression in Labrador retriever puppies

Abstract

Objective To evaluate methods used in the early radiographic detection of subtrochlear ulna sclerosis (STS), which could successfully predict the development of medial coronoid disease (MCD) in four-month-old puppies, and at the same time perform distal dynamic ulnar ostectomy (DDUO) to prevent or reduce disease development. Study design Retrospective descriptive radiographic study. Sample population One hundred and fifty-two Labrador retriever puppies from the South African Guide Dog Association were available for the study. Materials and methods Extended mediolateral radiographs were evaluated for STS by means of a subjective (score 0-3), as well as semi-quantitative and objective grading scores, given as a percentage of an STS region of interest compared to normal ulna medulla. Evaluations were performed by a surgery resident, specialist veterinary radiologist (SVR) and specialist veterinary surgeon. Lameness and pain were also evaluated and were combined with the STS scores to give a total joint involvement score. DDUO was performed on all elbows with >20% joint involvement. At 12-months-old, all dogs underwent elbow computed tomography to determine the development of MCD. Results The only method predictive of disease development was SVR’s subjective evaluation of STS, with a sensitivity of 46% and specificity of 81%. Twenty-two dogs not receiving surgery still developed MCD. One of 21 dogs receiving DDUO surgery developed MCD. The surgery had significant protective effects, with surgical candidates being 13 times less likely to develop MCD (odds ratio = 13.3, P = 0.026). Conclusion Labrador retrievers and other known at-risk breeds should be screened at four months of age for STS through radiographic assessment by an SVR. If deemed at risk, DDUO surgery is advised to prevent or reduce MCD development.