New Screening Protocol for Canine Elbow Dysplasia
The 2016 IEWG published a new x-ray protocol to help distinguish dogs with normal elbows from those with dysplasia.
Elbow dysplasia is a painful, inherited condition that is far more challenging for vets, owners and dogs to deal with than hip dysplasia. Yet little progress has been made in reducing its prevalence since breeders started screening breeding stock through the Orthopedic Foundation for Animals about two decades ago (Hou, Wang, et al, 2013). The International Elbow Working Group (IEWG) has tacked this issue and in the summer of 2016, they issues new screening guidelines and protocols.
We can definitely improve on our present “elbow clearance,” since per a Michigan State University study, many dogs with normal elbows are diagnosed by the OFA with Grade 1 elbow dysplasia and many dogs that actually have Grade 1 dysplasia are rated by the OFA as normal. These errors causes breeders to lose faith in the clearance process, questioning the ratings their dogs get. It also means that we are removing some dogs from the breeding pool for no reason and we are breeding dogs that may pass elbow dysplasia on to their offspring (Kunst et al, 2014).
This new IEWG protocol increases the number of x-rays from one to between 2 and 5. The number and quality of the x-rays improve accuracy, as does the experience of the reviewer. More details to come but here is the new protocol for you to share with your veterinarian.
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The 2017 IEWG meeting in Aug 2017 presented additional data on the new screening method for elbow dysplasia, including a screening form, which is also available on the IEWG website. Two xray views are highly recommended:
Elbows are individually evaluated using a 0 to 3 scoring system.
0 = Normal elbow joint (No evidence of incongruity, sclerosis or arthrosis)
1 = Mild arthrosis (Presence of osteophytes 2 mm, sclerosis of the base of the coronoid processes – trabecular pattern still visible
2 = Moderate arthrosis or suspect primary lesion (Presence of osteophytes 2 – 5 mm, obvious sclerosis (no trabecular pattern) of the base of the coronoid processes, step of 3-5 mm between radius and ulna (INCONGRUITY), indirect signs for other primary lesion (UAP, FCP/Coronoid disease, OCD)
3 = Severe arthrosis or evident primary lesion (Presence of osteophytes > 5 mm, step of > 5 mm between radius and ulna (obvious INCONGRUITY), obvious presence of a primary lesion (UAP, FCP, OCD))
Breeding combinations in several breeds were evaluated for the benefit of using elbow dysplasia screening in breeding stock to reduce ED rates. Improvement was shown in the four evaluated breeds, Golden Retrievers, German Shepherds, Labrador Retrievers and Saint Bernards. For Golden Retrievers, breeding two parents with Grade 0 elbows resulted in 80% of offspring having Grade 0, while breeding two parents with Grade 1 elbows, produced only 71% of offspring with Grade 0 elbows.
Hazewinkel, HAW. 2016. Mode of inheritance of Elbow Dysplasia and Principles of Screening Methods. Proceedings of the 30th annual meeting of the International Elbow Working Group
Hou Y, Wang Y, Lu X, Zhang X, Zhao Q, et al. (2013) Monitoring Hip and Elbow Dysplasia Achieved Modest Genetic Improvement of 74 Dog Breeds over 40 Years in USA. PLoS ONE 8(10): e76390. doi:10.1371/journal.pone.0076390
Kunst_et_al. 2014.COMPUTED TOMOGRAPHIC IDENTIFICATION OF DYSPLASIA AND PROGRESSION OF OSTEOARTHRITIS IN DOG ELBOWS PREVIOUSLY ASSIGNED OFA GRADES 0 AND 1, Veterinary Radiology & Ultrasound
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