elbow dysplasia

Elbow dysplasia is a significant genetically determined problem in many breeds of dog, often manifesting from puppyhood and continuing for life. In elbow dysplasia, the complex elbow joint suffers from a structural defect, often related to its cartilage. This initial condition, known as a "primary lesion", causes an abnormal level of wear and tear and gradual degradation of the joint, at times disabling or with chronic pain. Secondary processes such as inflammation and osteoarthritis can arise from this damage which increase the problem and add further problems of their own.

File:Head of femur avascular necrosis.jpg showing a flap of cartilage (osteochondritis dissecans) due to avascular necrosis. Similar cartilage damage in dogs causes wear in the joint leading to osteoarthritic processes and is a common cause of elbow dysplasia.]]

The most common cause is osteochondrosis, which is a disease of the joint cartilage, and osteochondritis dissecans (OCD or OD), the separation of a flap of cartilage from the joint surface as a result of avascular necrosis, which in turn arises from failed blood flow in the subchondral bone.{{cite web|url=http://www.medterms.com/script/main/art.asp?articlekey=11789|title=Definition of Osteochondritis dissecans|access-date=2009-02-20|author=Shiel WC Jr|publisher=MedicineNet, Inc.|archive-date=7 August 2012|archive-url=https://web.archive.org/web/20120807082548/http://www.medterms.com/script/main/art.asp?articlekey=11789|url-status=dead}}

In OCD, the normal change of cartilage to bone in the development of the joint fails or is delayed. The cartilage continues to grow and may split or become necrotic. The cause is uncertain, but possibly includes genetics, trauma, and nutrition (including excessive calcium and decreased vitamin C intake).{{cite book|author1=Ettinger, Stephen J. |author2=Feldman, Edward C. |title=Textbook of Veterinary Internal Medicine|edition=4th|publisher=W.B. Saunders Company|year=1995|isbn=0-7216-6795-3}} OCD lesions found in the elbow at the medial epicondyle of the humerus are caused by disturbed endochondral fusion of the epiphysis of the medial epicondyle with the distal end of the humerus, which may in turn be caused by avulsion of the epiphysis.{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/91305.htm|title=Elbow Dysplasia|year=2006|work=The Merck Veterinary Manual|access-date=2007-02-04}} Specific conditions related to OCD include fragmentation of the medial coronoid process of the ulna (FMCP) and an ununited anconeal process of the ulna (UAP). All types of OCD of the elbow are most typically found in large breed dogs, with symptoms starting between the ages of 4 and 8 months. Males are affected twice as often as females. The disease often affects both elbows (30 to 70 percent of the time), and symptoms include intermittent lameness, joint swelling, and external rotation and abduction of the paw.{{cite web | last = Hazewinkel | first = H.A.W. | title = Elbow Dysplasia; Clinical Aspects and Screening Programs | work = Proceedings of the 28th World Congress of the World Small Animal Veterinary Association | year = 2003 | url = http://www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2003&PID=6574&O=Generic | access-date = 2006-08-24 }} Osteoarthritis will develop later in most cases.

UAP is caused by a separation from the ulna of the ossification center of the anconeal process.{{cite web | title = Ununited Anoconeal Process | work = Fitzpatrick Referrals | year = 2014 | url = http://www.fitzpatrickreferrals.co.uk/our-services/surgery/conditions/fore-limb/ununited-anconeal-process-uap | access-date = 2014-01-14 }} FMCP is caused by a failure of the coronoid process to unite with the ulna.

Diagnosis is through x-rays, arthroscopy or CT (computed tomography). In cases with significant lameness, surgery is the best option, especially with UAP. However, conservative treatment is often enough for cases of FMCP and OCD of the medial humeral epicondyle. The dogs are exercised regularly and given pain medication, and between the ages of 12 and 18 months the lameness will often improve or disappear. Control of body weight is important in all cases of elbow dysplasia, and prevention of quick growth spurts in puppies may help to prevent the disease.

Surgery for FMCP consists of removal of cartilage and bone fragments and correction of any incongruity of the joint. Reattachment of UAP with a screw is usually attempted before the age of 24 weeks, and after that age the typical treatment is removal of the UAP.{{cite journal |vauthors=Demko J, McLaughlin R |title=Developmental orthopedic disease |journal=Vet Clin North Am Small Anim Pract |volume=35 |issue=5 |pages=1111–35, v |year=2005 |pmid=16129135 |doi=10.1016/j.cvsm.2005.05.002}} Without surgery, UAP rapidly progresses to osteoarthritis, but with FMCP osteoarthritis typically occurs with or without surgery. Osteoarthritis is also a common sequela of OCD of the humerus despite medical or surgical treatment. Elbow replacement surgery has been developed and can be an option for treatment.{{Cite web|url=https://vetspecialists.co.uk/fact-sheets/orthopaedics/|title=Orthopaedics Fact Sheets|accessdate=29 July 2023}}

File:Elbowdysplasia-dog.jpg

Conservative therapies include NSAIDs, pain medication, weight management and exercise restrictions.[http://www.asgvets.com/rdvms/innovations/ Innovations] asgvets.com {{dead link|date=July 2023}}

The elbow is a complex joint, bears 60% of body load, and tolerates problems less well than the hips.{{cite web|author=Brown |author2=Gilbert |author3=Broome |title=Total Elbow Replacement in Dogs |url=http://www.grove-vet.co.uk/downloads/total_elbow_replacement_dogs.pdf |publisher=Grove Orthopaedic Referrals |access-date=2010-07-17 |date=November 2005 |url-status=dead |archive-url=https://web.archive.org/web/20120309063251/http://www.grove-vet.co.uk/downloads/total_elbow_replacement_dogs.pdf |archive-date=2012-03-09 }} As a result, elbow replacement is more complex than hip replacement, rehabilitation can take significantly longer, and some degree of lameness will remain. The surgery is classified as of 2010 as a "salvage" operation - that is, a last resort for an otherwise viable animal.{{cite web|title=Elbow dysplasia 2 / OC and OCD|url=http://www.fitzpatrickreferrals.co.uk/our-services/surgery/conditions/fore-limb/canine-elbow-dysplasia|publisher=Fitzpatrick referrals|access-date=2014-01-14}} Success rates of around 80 - 85% (approximately 5 in 6) were being discussed by sources in 2005 and again in 2008.{{cite web|title=Total Elbow Replacement|url=http://www.cvm.umn.edu/vcs/sections/surgery/srl/topics/tjr/ter/home.html|publisher=University of Minnesota Veterinary Clinical Sciences dept|access-date=2010-07-17}}

There are also fewer options if the replacement fails; arthrodesis (surgical fusion of the joint) can result in a pain-free but lame gait. However, arthrodesis is itself a complex surgery with a long recovery time, and if arthrodesis is required, additional strain will be borne by other nearby joints, so other leg and shoulder conditions such as osteoarthritis may become more significant.

The Orthopedic Foundation for Animals in the United States will grade elbow X-rays of dogs intended for breeding.

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Category:Dog musculoskeletal disorders