The intra‐ and intertester repeatability of radiographic elbow incongruity grading is high in chondrodystrophic dog breeds

Abstract

Elbow incongruity is a form of elbow dysplasia that causes osteoarthritis, pain, and lameness, and it is common in chondrodystrophic dog breeds. The objective of this retrospective secondary analysis study was to evaluate the intra-and interobserver repeatability of a novel radiographic incongruity grading system for assessing elbow incongruity in three chondrodystrophic dog breedsthe dachshund, Skye Terrier, and Glen of Imaal Terrier. We conducted an observer agreement study that included 220 mediolateral antebrachial radiographs from 110 dogs with the elbow in 90 • flexion. The radiographs were independently assessed by three observers at three time points, using a four-stepped grading scale. The proportion of agreement and Kappa coefficient were calculated. Both the intra-and interobserver proportions of agreement were substantial when three grades were required to be identical (.705-.777 and .609, respectively), and almost perfect for two identical grades (.991-1.000 and .991, respectively). Some differences in repeatability between breeds were noted; specifically, the intraobserver repeatability was higher in the dachshund, and the interobserver repeatability was lower in the Glen of Imaal Terrier. Our study showed that the radiographic imaging protocol and incongruity grading system have high repeatability when assessing elbow incongruity in chondrodystrophic dog breeds. K E Y W O R D Schondrodystrophic dog, elbow dysplasia, incongruity, reliability, validity

Repeatability of radiographic assessments for feline hip dysplasia suggest consensus scores in radiology are more uncertain than commonly assumed

“…In this study we show that intra- and inter-observer agreement on diagnostic scoring of FHD radiographs suffers from the same issues of repeatability as has been found not only in canine hip dysplasia 4 , 5 , 8 , 9 , but more generally with radiographic disease interpretation in animals and humans 7 , 12 , 13 , 22 . To place this observational uncertainty into a practical context, we also quantified the direction and magnitude of what could be expected if a ‘second opinion’ on a hip assessment was sought within this programme, and the degree to which consensus scoring improves diagnostic repeatability.…”

“…An example of how a deeper understanding of uncertainty and inaccuracy in consensus scores may dramatically change the interpretation of results, can be seen by comparing our study to Pulkinnen et al 12 . In both studies the probability of achieving a full independent consensus score (i.e.…”

“…all three radiologists agree) during an assessment was similar (56 versus 61%); as was a restricted consensus score where only two out of three grades needed to be identical during an assessment (98 versus 99%). In Pulkinnen et al 12 , this near perfect probability of reaching a majority agreement during an assessment was then used to justify their radiological assessment criteria. However, this requires a strong assumption that consensus scores reflect diagnostic accuracy.…”

“…Discrepancies in radiological evaluations are common amongst radiologists 1 , 2 , with a wealth of studies in both human and veterinary medical fields documenting surprisingly large intra- and inter-observer assessment variation derived from the same radiographs (e.g. 1 , 3 – 12 . It is becoming increasingly apparent that this variation between and within observers occurs because of natural uncertainty in the process of interpreting radiographs, as well as ubiquitous factors that contribute to radiological error 1 , 2 , 13 .…”

Evaluation of the Radial Procurvatum Using the Center of Rotation of Angulation Methodology in Chondrodystrophic Dogs

“…Retardation of growth of the distal ulnar physis (growth plate) results in a shortened ulna (4)(5)(6)(7), which may lead to cranial bowing of the radius, valgus deformity at the carpal joint, and elbow subluxation (8,9). In particular, chondrodystrophic breeds have impaired growth of the long bones, and often have a prematurely closed distal ulnar growth plate, resulting in angular deformities (10,11).…”