Radiographic analysis of trochlear notch sclerosis in the diagnosis of osteoarthritis secondary to medial coronoid disease

Abstract

SummaryTrochlear notch sclerosis (TNS) as assessed by radiography has been shown to be increased in elbow dysplasia (ED) associated medial coronoid process disease (MCD). The aims of this study were to investigate whether two defined radiographic tests evaluating TNS would increase the sensitivity of detecting osteoarthritis secondary to MCD, and to assess whether there was a correlation between increasing TNS with severity of MCD. Sixty-one dogs with MCD (121 elbows) were selected from the imaging database. The controls were nine cadavers (18 disease-free elbows). Standard International Elbow Working Group radiographs and CT scans were taken of each elbow. Plain radiographs were analysed using various assessments: osteophyte grade (0–3), coronoid grade (0–3), TNS descriptive grade (0–3) and TNS ratio. The TNS ratio was calculated from the depth of ulnar sclerosis at the level of the disto-cranial margin of the humeral condyles divided by the cranio-caudal ulna depth. The TNS descriptive assessment and ratio both increased the overall sensitivity of diagnosing osteoarthritis secondary to MCD above the other radiographic tests. The sensitivity of the TNS ratio at <0.3 mm was 91%-96% and the TNS descriptive assessment was 77%-96%. Radio-graphic TNS significantly increased with increasing severity of coronoid disease grade as evaluated by CT p<0.01. The finding that TNS increases the sensitivity of diagnosing osteoarthritis secondary to MCD is valuable to those that have neither a CT scanner nor arthroscopy readily available. The assessments described in this study are easy to apply and do not require any sophisticated technology in order to detect sclerosis.

Digital Analysis of Subtrochlear Sclerosis in Elbows Submitted for Dysplasia Screening

“…The results allow us to accept the investigated hypothesis and exclude the null hypothesis for ROI-1 and ROI-2 (most distal and cranial regions of UTN), as the pixel intensity of the UTN subchondral bone in the dysplastic elbows was higher than that of the normal elbow (ED Grade 0) set of contralateral joints. Previous studies had already indicated these anatomic areas as the most predisposed regions for the evidence of UTN sclerosis ( 2 , 11 , 12 ). However, the differences in UTN radio-opacity registered in our research were very small, which did not allow us to recommend this methodology for clinical or ED scoring purposes.…”

“…Radiographs are scored as Grade 0 (no signs of ED) or Grade 1, 2, or 3 (dysplastic joints), depending on the analysis of the radiographic findings: level of UTN sclerosis, osteophyte size, or signs of primary elbow lesions. Our template was developed on ImageJ software in order to cover the entire UTN subchondral bone, without the overlapping of other bone structures, and to individualize the areas of interest, indicated in previous studies as the most suitable for detecting UTN sclerosis ( 2 , 11 , 12 ).…”

“…In ED, UTN sclerosis has been linked to increased stiffness of subchondral bone and higher vulnerability of articular cartilage to injury ( 19 ). Previous studies concluded that there is a statistically significant association between UTN sclerosis and medial coronoid disease ( 2 , 6 , 8 , 12 ), especially when sclerosis is localized in the more distal part of the UTN ( 11 ). Quantification of bone density of the medial coronoid process in sound dogs and dogs with fragmented coronoid process (FCP) has also been reported ( 8 ).…”

“…This subjectivity is compounded by images with different levels of radiographic exposure, different degrees of joint flexion or other changes associated with the dog's positioning, and variation between breeds. Recently, some studies have been carried out, which associate the increased image pixel values (radio-opacity) of UTN subchondral bone in digital images, evaluated by computerized image analysis, with clinical MCD in dogs ( 2 , 11 , 12 ). However, there are no studies exploring the computerized quantification of UTN sclerosis and relating the degree of sclerosis with ED grades.…”

Comparative evaluation of radiographic and computed tomographic findings in dogs with bilateral medial coronoid disease (MCD) presenting with unilateral forelimb lameness

“…Radioulnar incongruity also seems to play an important role [ 2 , 15 ]. Regardless of a variable sensitivity, radiographic examination is always the first choice for ED screening in practice [ 16 – 18 ]. However, due to both superimposition of the radial head over the medial coronoid process and osteophytes, a correct assessment of the MCP is not always possible [ 19 ].…”