Title: Elbow dysplasia

{{Short description|Medical condition in dogs}}
{{Use dmy dates|date=August 2022}}
[[File:X-ray image of an isolates processus anconaeus in a 5 year old German shepherd dog.jpg|thumb|Ununited anconeal process]]
'''Elbow dysplasia''' is a condition involving multiple developmental abnormalities of the [[elbow-joint]] in the [[dog]], specifically the growth of [[cartilage]] or the structures surrounding it. These abnormalities, known as 'primary lesions', give rise to [[osteoarthritis|osteoarthritic processes]].&lt;ref name=&quot;Pead and Guthrie&quot;&gt;Quoted from: {{cite web|author1=Matthew Pead|author2=Sue Guthrie|title=Elbow Dysplasia in dogs - a new scheme explained|url=http://www.bva.co.uk/public/documents/chs_elbow.pdf|publisher=[[British Veterinary Association]] (BVA)|access-date=2010-07-16|url-status=dead|archive-url=https://web.archive.org/web/20111002022122/http://www.bva.co.uk/public/documents/chs_elbow.pdf|archive-date=2011-10-02}}&lt;/ref&gt; Elbow dysplasia is a common condition of certain breeds of dogs.

Most primary lesions are related to [[osteochondrosis]], a disease of the joint [[cartilage]], and [[osteochondritis dissecans]] (OCD), the separation of a flap of cartilage on the joint surface. Other common causes of elbow dysplasia include an ununited [[Elbow|anconeal process]] (UAP) and fragmented or ununited medial coronoid process (FCP or FMCP).&lt;ref name=&quot;Pead and Guthrie&quot; /&gt;

Osteochondritis dissecans is difficult to diagnose clinically as the animal may only exhibit an unusual gait. Consequently, OCD may be masked by, or misdiagnosed as, other skeletal and joint conditions such as [[Hip dysplasia (canine)|hip dysplasia]].&lt;ref name=&quot;Ch.84OCD&quot;&gt;{{cite book|vauthors=Lenehan TM, Van Sickle DC|veditors=Nunamaker DM, Newton CD|chapter=Chapter 84: Canine osteochondrosis|chapter-url=http://cal.vet.upenn.edu/projects/saortho/chapter_84/84mast.htm|title=Textbook of small animal orthopaedics|url=http://cal.vet.upenn.edu/projects/saortho/index.html|publisher=Lippincott|location=Philadelphia|year=1985|isbn=0-397-52098-0|access-date=17 July 2010|archive-date=3 July 2017|archive-url=https://web.archive.org/web/20170703170539/http://cal.vet.upenn.edu/projects/saortho/index.html|url-status=dead}}&lt;/ref&gt; The problem develops in puppyhood, although often is subclinical, and there may be pain or stiffness, discomfort on extension, or other compensating characteristics.&lt;ref name=&quot;Ch.84OCD&quot; /&gt; Diagnosis generally depends on X-rays, [[arthroscopy]], or [[MRI]] scans.&lt;ref name=&quot;Ch.84OCD&quot; /&gt; While cases of OCD of the stifle go undetected and heal spontaneously, others are exhibited in acute lameness.&lt;ref name=&quot;Ch.84OCD&quot; /&gt; Surgery is recommended once the animal has been deemed lame; otherwise, non-surgical control is usually used.&lt;ref name=&quot;Ch.84OCD&quot; /&gt;

== The disease ==
Elbow dysplasia is a significant genetically determined problem in many [[dog breeds|breeds of dog]], often manifesting from [[puppy]]hood and continuing for life.&lt;ref name=&quot;Pead and Guthrie&quot; /&gt; In elbow dysplasia, the complex elbow joint suffers from a structural defect, often related to its [[cartilage]].&lt;ref name=&quot;Pead and Guthrie&quot; /&gt; This initial condition, known as a &quot;primary lesion&quot;,&lt;ref name=&quot;Pead and Guthrie&quot; /&gt; causes an abnormal level of wear and tear and gradual degradation of the joint, at times [[disability|disabling]] or with [[chronic pain]].  Secondary processes such as [[inflammation]] and [[osteoarthritis]] can arise from this damage&lt;ref name=&quot;Pead and Guthrie&quot; /&gt; which increase the problem and add further problems of their own.

== Causes ==
[[File:Head of femur avascular necrosis.jpg|thumb|right|250px|Human [[femur head]] showing a flap of [[cartilage]] ([[osteochondritis dissecans]]) due to [[avascular necrosis]]. Similar cartilage damage in dogs causes wear in the joint leading to [[osteoarthritis|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&lt;ref name=&quot;Pead and Guthrie&quot; /&gt; as a result of [[avascular necrosis]], which in turn arises from failed [[blood circulation|blood flow]] in the [[subchondral bone]].&lt;ref&gt;{{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}}&lt;/ref&gt;

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 [[necrosis|necrotic]]. The cause is uncertain, but possibly includes [[genetics]], [[Physical trauma|trauma]], and nutrition (including excessive [[calcium]] and decreased [[vitamin C]] intake).&lt;ref name=Ettinger_1995&gt;{{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}}&lt;/ref&gt; 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 fracture|avulsion]] of the epiphysis.&lt;ref&gt;{{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}}&lt;/ref&gt; 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.&lt;ref name=Ettinger_1995/&gt;  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 (kinesiology)|abduction]] of the paw.&lt;ref name=Hazewinkel&gt;{{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&amp;PID=6574&amp;O=Generic | access-date = 2006-08-24 }}&lt;/ref&gt;  [[Osteoarthritis]] will develop later in most cases.

UAP is caused by a separation from the ulna of the [[ossification center]] of the [[anconeal process]].&lt;ref&gt;{{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 }}&lt;/ref&gt;  FMCP is caused by a failure of the [[Coronoid process of the ulna|coronoid process]] to unite with the ulna.

== Diagnosis and treatment ==
Diagnosis is through [[x-ray]]s, [[arthroscopy]] or CT ([[CT scan|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.&lt;ref name=Ettinger_1995/&gt;  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.&lt;ref name=VCNA&gt;{{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}}&lt;/ref&gt;  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.&lt;ref name=VCNA/&gt; Elbow replacement surgery has been developed and can be an option for treatment.&lt;ref&gt;{{Cite web|url=https://vetspecialists.co.uk/fact-sheets/orthopaedics/|title=Orthopaedics Fact Sheets|accessdate=29 July 2023}}&lt;/ref&gt;
[[File:Elbowdysplasia-dog.jpg|thumb|Fragmentation of the medial coronoid process]]

=== Non-surgical treatment ===
Conservative therapies include [[Nonsteroidal anti-inflammatory drug|NSAIDs]], pain medication, [[weight management]] and exercise restrictions.&lt;ref&gt;[http://www.asgvets.com/rdvms/innovations/ Innovations] asgvets.com {{dead link|date=July 2023}}&lt;/ref&gt;

===Total elbow replacement===
The elbow is a complex joint, bears 60% of body load, and tolerates problems less well than the hips.&lt;ref name=&quot;grove TER&quot;&gt;{{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 }}&lt;/ref&gt; As a result, elbow replacement is more complex than [[hip replacement (animal)|hip replacement]], rehabilitation can take significantly longer, and some degree of lameness will remain.&lt;ref name=&quot;grove TER&quot; /&gt; The surgery is classified as of 2010 as a &quot;salvage&quot; operation - that is, a last resort for an otherwise viable animal.&lt;ref&gt;{{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}}&lt;/ref&gt; Success rates of around 80 - 85% (approximately 5 in 6) were being discussed by sources in 2005&lt;ref name=&quot;grove TER&quot; /&gt; and again in 2008.&lt;ref&gt;{{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}}&lt;/ref&gt;

There are also fewer options if the replacement fails; [[arthrodesis]] (surgical fusion of the joint) can result in a pain-free but lame gait.&lt;ref name=&quot;grove TER&quot; /&gt; However, arthrodesis is itself a complex surgery with a long recovery time,&lt;ref name=&quot;grove TER&quot; /&gt; 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.&lt;ref name=&quot;grove TER&quot; /&gt;

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

== References ==
{{Reflist}}

{{DEFAULTSORT:Elbow dysplasia}}
[[Category:Dog musculoskeletal disorders]]