Title: Osteochondritis dissecans

{{short description|Ischemic bone disease}}
{{cs1 config|name-list-style=vanc}}
{{other uses of|OCD}}
{{Use dmy dates|date=August 2018}}
{{Infobox medical condition (new)
| name            = Osteochondritis dissecans
| synonyms        = 
| image           = Head of femur avascular necrosis.jpg
| caption         = A large [[Osteochondritis dissecans#Hinged lesions|flap lesion]] in the [[femur head]] typical of late stage Osteochondritis dissecans. In this case, the lesion was caused by [[avascular necrosis]] of the bone just under the cartilage.
| pronounce       = {{IPAc-en|ˌ|ɒ|s|t|i|.|oʊ|k|ɒ|n|ˈ|d|r|aɪ|t|ɪ|s|_|ˈ|d|ɪ|s|ᵻ|k|æ|n|z}}
| field           = 
| symptoms        = 
| unicorns  = 
| onset           = 
| duration        = 
| types           = 
| causes          = 
| risks           = 
| diagnosis       = 
| differential    = 
| prevention      = 
| treatment       = 
| medication      = 
| prognosis       = 
| frequency       = 
| deaths          = 
}}
&lt;!-- Definition and symptoms --&gt;
'''Osteochondritis dissecans''' ('''OCD''' or '''OD''') is a [[joint]] disorder primarily of the subchondral bone in which cracks form in the [[articular cartilage]] and the underlying [[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=20 February 2009|vauthors=Shiel Jr WC|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; OCD usually causes pain during and after sports. In later stages of the disorder there will be [[Swelling (medical)|swelling]] of the affected joint that catches and locks during movement. [[Physical examination]] in the early stages does only show pain as symptom, in later stages there could be an [[Joint effusion|effusion]], tenderness, and a [[crepitus|crackling sound with joint movement]].

&lt;!-- Cause and diagnosis --&gt;
OCD is caused by blood deprivation of the secondary physes around the bone core of the femoral condyle. This happens to the epiphyseal vessels under the influence of repetitive overloading of the joint during running and jumping sports. During growth such chondronecrotic areas grow into the subchondral bone. There it will show as bone defect area under articular cartilage. The bone will then possibly heal to the surrounding condylar bone in 50% of the cases. Or it will develop into a pseudarthrosis between condylar bone core and osteochondritis flake leaving the articular cartilage it supports prone to damage. The damage is executed by ongoing sport overload. The result is fragmentation ([[Dissection (medical)|dissection]]) of both cartilage and bone, and the free movement of these bone and cartilage fragments within the joint space, causing pain, blockage and further damage.&lt;ref&gt;{{cite journal | vauthors = Pappas AM | title = Osteochondrosis dissecans | journal = Clinical Orthopaedics and Related Research | issue = 158 | pages = 59–69 | year = 1981 | volume = 158 | pmid = 7273527 | doi = 10.1097/00003086-198107000-00009 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Woodward AH, Bianco AJ | title = Osteochondritis dissecans of the elbow | journal = Clinical Orthopaedics and Related Research | volume = 110 | issue = 110 | pages = 35–41 | year = 1975 | pmid = 1157398 | doi = 10.1097/00003086-197507000-00007 }}&lt;/ref&gt;&lt;ref&gt;{{cite book| vauthors = Pettrone FA |year=1986|title=American Academy of Orthopaedic Surgeons Symposium on Upper Extremity Injuries in Athletes|location=St. Louis, Missouri|publisher=CV Mosby|isbn=978-0-8016-0026-5|pages=193–232}}&lt;/ref&gt; OCD has a typical anamnesis with pain during and after sports without any history of trauma. Some symptoms of late stages of osteochondritis dissecans are found with other diseases like rheumatoid disease of children and meniscal ruptures. The disease can be confirmed by [[Radiography|X-rays]], [[computed tomography]] (CT) or [[magnetic resonance imaging]] (MRI) scans.

&lt;!-- Treatment --&gt;
Non-surgical treatment is successful in 50% of the cases. If in late stages the lesion is unstable and the cartilage is damaged, surgical intervention is an option as the ability for articular cartilage to heal is limited. When possible, non-operative forms of management such as protected reduced or non-weight bearing and immobilization are used. Surgical treatment includes arthroscopic drilling of intact lesions, securing of cartilage flap lesions with pins or screws, drilling and replacement of cartilage plugs, [[Stem cell transplantation for articular cartilage repair|stem cell transplantation]], and in very difficult situation in adults joint replacement. After surgery rehabilitation is usually a two-stage process of unloading and [[physical therapy]]. Most rehabilitation programs combine efforts to protect the joint with muscle strengthening and range of motion. During an immobilization period, [[isotonic contraction|isotonic exercise]]s, such as straight leg raises, are commonly used to restore muscle loss without disturbing the cartilage of the affected joint. Once the immobilization period has ended, physical therapy involves continuous passive motion (CPM) and/or low impact activities, such as walking or swimming.

&lt;!-- Epidemiology and history --&gt;
OCD occurs in 15 to 30 people per 100,000 in the general population each year.&lt;ref name=&quot;pmid9012566&quot;/&gt; Although rare, it is an important cause of joint pain in physically active children and [[adolescent]]s.&lt;ref&gt;{{cite journal | vauthors = Inoue G | title = Bilateral osteochondritis dissecans of the elbow treated by Herbert screw fixation | journal = British Journal of Sports Medicine | volume = 25 | issue = 3 | pages = 142–4 | date = September 1991 | pmid = 1777781 | pmc = 1478853 | doi = 10.1136/bjsm.25.3.142 }} See introduction and discussion sections on incidence&lt;/ref&gt; Because their bones are still growing, adolescents are more likely than adults to recover from OCD; recovery in adolescents can be attributed to the bone's ability to repair damaged or dead bone tissue and cartilage in a process called bone remodeling. While OCD may affect any joint, the knee tends to be the most commonly affected, and constitutes 75% of all cases. [[Franz König (surgeon)|Franz König]] coined the term osteochondritis dissecans in 1887, describing it as an [[inflammation]] of the bone–[[cartilage]] interface. Many other conditions were once confused with OCD when attempting to describe how the disease affected the joint, including osteochondral fracture, [[osteonecrosis]], accessory ossification center, [[osteochondrosis]], and hereditary epiphyseal [[dysplasia]]. Some authors have used the terms ''osteochondrosis dissecans'' and ''osteochondral fragments'' as [[synonym]]s for OCD.
{{TOC limit|3}}

==Signs and symptoms==
In osteochondritis dissecans, fragments of [[cartilage]] or bone become loose within a joint, leading to pain and [[inflammation]]. These fragments are sometimes referred to as joint mice.&lt;ref&gt;{{cite journal|vauthors=Hixon AL, Gibbs LM|title=What Should I Know About Osteochondritis Dissecans?|journal=American Family Physician|volume=61|issue=1|page=158|date=January 2000|url=http://www.aafp.org/afp/20000101/20000101d.html|access-date=29 August 2008|archive-date=13 November 2011|archive-url=https://web.archive.org/web/20111113031443/http://www.aafp.org/afp/20000101/20000101d.html|url-status=dead}}&lt;/ref&gt; OCD is a type of [[osteochondrosis]] in which a [[lesion]] has formed within the cartilage layer itself, giving rise to secondary inflammation. OCD most commonly affects the knee, although it can affect other joints such as the ankle or the elbow.&lt;ref name=&quot;pmid6807595&quot;/&gt;

People with OCD report activity-related pain that develops gradually. Individual complaints usually consist of mechanical symptoms including pain, swelling, catching, locking, popping noises, and buckling / giving way; the primary presenting symptom may be a restriction in the range of movement.&lt;ref name=&quot;pmid10643956&quot;&gt;{{cite journal | vauthors = Hixon AL, Gibbs LM | title = Osteochondritis dissecans: a diagnosis not to miss | journal = American Family Physician | volume = 61 | issue = 1 | pages = 151–6, 158 | date = January 2000 | pmid = 10643956 | url = http://www.aafp.org/afp/20000101/151.html | access-date = 13 September 2008 | archive-date = 6 June 2011 | archive-url = https://web.archive.org/web/20110606043721/http://www.aafp.org/afp/20000101/151.html | url-status = dead }}&lt;/ref&gt; Symptoms typically present within the initial weeks of stage&amp;nbsp;I. The onset of stage&amp;nbsp;II occurs within months and offers little time for diagnosis. The disease progresses rapidly beyond stage&amp;nbsp;II, as OCD lesions quickly move from stable cysts or fissures to unstable fragments. [[Non-specific symptom]]s, caused by similar injuries such as [[sprain]]s and [[strain (injury)|strains]], can delay a definitive diagnosis.&lt;ref&gt;{{cite web|url=http://www.eorthopod.com/osteochondritis-dissecans-of-the-knee/topic/68|title=Adolescent Osteochondritis Dissecans of the Knee|access-date=21 September 2008|author=eOrthopod.com|publisher=Medical Multimedia Group, LLC|url-status=dead|archive-url=https://web.archive.org/web/20141001222250/http://www.eorthopod.com/osteochondritis-dissecans-of-the-knee/topic/68|archive-date=1 October 2014}}&lt;/ref&gt;

Physical examination typically reveals fluid in the joint, tenderness, and [[crepitus]]. The tenderness may initially spread, but often reverts to a well-defined focal point as the lesion progresses. Just as OCD shares symptoms with common maladies, acute osteochondral fracture has a similar presentation with tenderness in the affected joint, but is usually associated with a fatty [[hemarthrosis]]. Although there is no significant pathologic gait or characteristic alignment abnormality associated with OCD, the patient may walk with the involved leg externally rotated in an attempt to avoid [[tibia]]l spine impingement on the [[lateral (anatomy)|lateral]] aspect of the [[Medial condyle of femur|medial condyle of the femur]].&lt;ref name=&quot;pmid8613454&quot;&gt;{{cite journal | vauthors = Schenck RC, Goodnight JM | title = Osteochondritis dissecans | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 78 | issue = 3 | pages = 439–56 | date = March 1996 | pmid = 8613454 | doi = 10.2106/00004623-199603000-00018 | url = http://www.ejbjs.org/cgi/content/full/78/3/439 | url-status = dead | archive-url = https://web.archive.org/web/20081007082532/http://www.ejbjs.org/cgi/content/full/78/3/439 | archive-date = 7 October 2008 | url-access = subscription }}&lt;/ref&gt;

==Causes==
{{see also|Osteochondrosis}}
Despite much research, the [[etiology|causes]] remain unclear but include repetitive [[physical trauma]], [[ischemia]] (restriction of blood flow), [[hereditary]] and [[endocrine]] factors, [[avascular necrosis]] (loss of blood flow), rapid growth, deficiencies and imbalances in the ratio of calcium to phosphorus, and problems of [[ossification|bone formation]].&lt;ref&gt;{{cite journal | vauthors = Federico DJ, Lynch JK, Jokl P | title = Osteochondritis dissecans of the knee: a historical review of etiology and treatment | journal = Arthroscopy | volume = 6 | issue = 3 | pages = 190–7 | year = 1990 | pmid = 2206181 | doi = 10.1016/0749-8063(90)90074-N | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Hefti F, Beguiristain J, Krauspe R, Möller-Madsen B, Riccio V, Tschauner C, Wetzel R, Zeller R | title = Osteochondritis dissecans: a multicenter study of the European Pediatric Orthopedic Society | journal = Journal of Pediatric Orthopedics. Part B | volume = 8 | issue = 4 | pages = 231–45 | date = October 1999 | pmid = 10513356 | doi = 10.1097/00009957-199910000-00001 | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Langer F, Percy EC | title = Osteochondritis dissecans and anomalous centres of ossification: a review of 80 lesions in 61 patients | journal = Canadian Journal of Surgery | volume = 14 | issue = 3 | pages = 208–15 | date = May 1971 | pmid = 4996078 }}&lt;/ref&gt;&lt;ref&gt;{{cite book| vauthors = Geor RJ, Kobluk CN, Ames TR |year=1995|title=The Horse: Diseases and Clinical Management|location=Philadelphia, PA|publisher=W.B. Saunders|isbn=0-443-08777-6}}&lt;/ref&gt; Although the name &quot;osteochondritis&quot; implies [[inflammation]], the lack of inflammatory cells in [[Histology|histological]] examination suggests a non-inflammatory cause. It is thought that repetitive [[microtrauma]], which leads to microfractures and sometimes an interruption of blood supply to the subchondral bone, may cause subsequent localized loss of blood supply or alteration of growth.&lt;ref&gt;{{cite journal | vauthors = Ytrehus B, Carlson CS, Ekman S | title = Etiology and pathogenesis of osteochondrosis | journal = Veterinary Pathology | volume = 44 | issue = 4 | pages = 429–48 | date = July 2007 | pmid = 17606505 | doi = 10.1354/vp.44-4-429 | s2cid = 12349380 | url = http://www.vetpathology.org/cgi/reprint/44/4/429.pdf | url-status = dead | format = PFD | archive-url = https://web.archive.org/web/20090318145633/http://www.vetpathology.org/cgi/reprint/44/4/429.pdf | archive-date = 18 March 2009 }}&lt;/ref&gt;

[[Physical trauma|Trauma]], rather than avascular necrosis, is thought to cause osteochondritis dissecans in juveniles.&lt;ref&gt;{{cite journal | vauthors = Milgram JW | title = Radiological and pathological manifestations of osteochondritis dissecans of the distal femur. A study of 50 cases | journal = Radiology | volume = 126 | issue = 2 | pages = 305–11 | date = February 1978 | pmid = 622473 | doi = 10.1148/126.2.305 }}&lt;/ref&gt; In adults, trauma is thought to be the main or perhaps the sole cause, and may be [[endogenous]], [[exogenous]] or both.&lt;ref&gt;{{cite journal|author=Roberts N|title=Book Reviews|journal=Journal of Bone and Joint Surgery. British Volume|volume=43|issue=2|page=409|date=March 1961|doi=10.1302/0301-620X.43B2.409|doi-access=}}&lt;/ref&gt; The incidence of [[repetitive strain injury]] in young athletes is on the rise and accounts for a significant number of visits to primary care;&lt;ref name=&quot;pmid18556892&quot;&gt;{{cite journal | vauthors = Powers R | title = An ice hockey player with an unusual elbow injury. Osteochondritis dissecans | journal = JAAPA | volume = 21 | issue = 5 | pages = 62–3 | date = May 2008 | pmid = 18556892 | doi = 10.1097/01720610-200805000-00019 }}&lt;/ref&gt; this reinforces the theory that OCD may be associated with increased participation in sports and subsequent trauma.&lt;ref name=&quot;pmid18556892&quot;/&gt;&lt;ref name=&quot;pmid16794036&quot;&gt;{{cite journal | vauthors = Kocher MS, Tucker R, Ganley TJ, Flynn JM | title = Management of osteochondritis dissecans of the knee: current concepts review | journal = The American Journal of Sports Medicine | volume = 34 | issue = 7 | pages = 1181–91 | date = July 2006 | pmid = 16794036 | doi = 10.1177/0363546506290127 | s2cid = 24877474 }}&lt;/ref&gt; High-impact sports such as gymnastics, soccer, basketball, lacrosse, football, tennis, squash, baseball and weight lifting may put participants at a higher risk of OCD in stressed joints (knees, ankles and elbows).&lt;ref name=&quot;pmid10643956&quot;/&gt;&lt;ref&gt;{{cite web |url= http://www.emedicine.com/sports/TOPIC51.HTM |title=Humeral Capitellum Osteochondritis Dissecans|access-date=16 November 2008| vauthors = Patel S, Fried GW, Marone PJ |date=6 August 2008|work=[[eMedicine]]|publisher=[[Medscape]]}}&lt;/ref&gt;

Recent case reports suggest that some people may be genetically predisposed to OCD.&lt;ref&gt;{{cite journal | vauthors = Kenniston JA, Beredjiklian PK, Bozentka DJ | title = Osteochondritis dissecans of the capitellum in fraternal twins: case report | journal = The Journal of Hand Surgery | volume = 33 | issue = 8 | pages = 1380–3 | date = October 2008 | pmid = 18929205 | doi = 10.1016/j.jhsa.2008.05.008 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Livesley PJ, Milligan GF | title = Osteochondritis dissecans patellae. Is there a genetic predisposition? | journal = International Orthopaedics | volume = 16 | issue = 2 | pages = 126–9 | year = 1992 | pmid = 1428308 | doi = 10.1007/BF00180201 | s2cid = 24221990 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Tobin WJ | title = Familial osteochondritis dissecans with associated tibia vara | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 39-A | issue = 5 | pages = 1091–105 | date = October 1957 | pmid = 13475409 | doi = 10.2106/00004623-195739050-00010 | url = http://www.ejbjs.org/cgi/reprint/39/5/1091.pdf | url-status = dead | archive-url = https://web.archive.org/web/20090318145633/http://www.ejbjs.org/cgi/reprint/39/5/1091.pdf | archive-date = 18 March 2009 }}&lt;/ref&gt; Families with OCD may have mutations in the [[aggrecan]] gene.&lt;ref&gt;{{cite journal | vauthors = Bates JT, Jacobs JC, Shea KG, Oxford JT | title = Emerging genetic basis of osteochondritis dissecans | journal = Clinics in Sports Medicine | volume = 33 | issue = 2 | pages = 199–220 | date = April 2014 | pmid = 24698039 | pmc = 3976886 | doi = 10.1016/j.csm.2013.11.004 }}&lt;/ref&gt; Studies in horses have implicated specific genetic defects.&lt;ref&gt;{{cite journal | vauthors = Wittwer C, Dierks C, Hamann H, Distl O | title = Associations between candidate gene markers at a quantitative trait locus on equine chromosome 4 responsible for osteochondrosis dissecans in fetlock joints of South German Coldblood horses | journal = The Journal of Heredity | volume = 99 | issue = 2 | pages = 125–9 | date = March–April 2008 | pmid = 18227080 | doi = 10.1093/jhered/esm106 | doi-access = free }}&lt;/ref&gt;

==Pathophysiology==
[[File:Osteochondritis dissecans diagram.JPEG|thumb|Tunnel or notch view X-ray of the right knee from a patient with osteochondritis dissecans—cystic changes and irregular border are indicated by arrows on the [[Anatomical terms of location|medial]] side compared to the [[Anatomical terms of location|lateral]] side]]
Osteochondritis dissecans differs from &quot;wear and tear&quot; degenerative [[osteoarthritis|arthritis]], which is primarily an articular surface problem. Instead, OCD is a problem of the bone underlying the cartilage, which may secondarily affect the articular cartilage. Left untreated, OCD can lead to the development of degenerative arthritis secondary to joint incongruity and abnormal wear patterns.&lt;ref&gt;{{cite journal | vauthors = Detterline AJ, Goldstein JL, Rue JP, Bach BR | title = Evaluation and treatment of osteochondritis dissecans lesions of the knee | journal = The Journal of Knee Surgery | volume = 21 | issue = 2 | pages = 106–15 | date = April 2008 | pmid = 18500061 | doi = 10.1055/s-0030-1247804 | s2cid = 7392708 }}&lt;/ref&gt;

OCD occurs when a loose piece of bone or cartilage partially (or fully) separates from the end of the bone, often because of a loss of blood supply ([[osteonecrosis]]) and decalcification of the [[Trabecular bone|trabecular bone matrix]]. The loose piece may stay in place or slide around, making the [[joint]] stiff and unstable. OCD in humans most commonly affects the knees,&lt;ref name=&quot;pmid6807595&quot;&gt;{{cite journal | vauthors = Clanton TO, DeLee JC | title = Osteochondritis dissecans. History, pathophysiology and current treatment concepts | journal = Clinical Orthopaedics and Related Research | volume = 167 | issue = 167 | pages = 50–64 | date = July 1982 | pmid = 6807595 | doi = 10.1097/00003086-198207000-00009 }}&lt;/ref&gt; ankles, and elbow but can affect any joint.&lt;ref name=&quot;pmid17980849&quot;&gt;{{cite journal | vauthors = Kadakia AP, Sarkar J | title = Osteochondritis dissecans of the talus involving the subtalar joint: a case report | journal = The Journal of Foot and Ankle Surgery | volume = 46 | issue = 6 | pages = 488–92 | year = 2007 | pmid = 17980849 | doi = 10.1053/j.jfas.2007.06.005 }}&lt;/ref&gt;

In skeletally immature individuals, the blood supply to the [[epiphyseal plate|epiphyseal bone]] is good, supporting both [[osteogenesis]] and [[chondrogenesis]]. With disruption of the epiphyseal plate vessels, varying degrees and depth of [[necrosis]] occur, resulting in a cessation of growth to both [[osteocytes]] and [[chondrocytes]]. In turn, this pattern leads to disordered ossification of cartilage, resulting in subchondral [[avascular necrosis]] and consequently OCD.&lt;ref name=&quot;topic57webmd&quot;&gt;{{cite web|url=http://emedicine.medscape.com/article/89718-overview|title=Knee Osteochondritis Dissecans|access-date=2 October 2008|vauthors=Jacobs B, Ertl JP, Kovacs G, Jacobs JA |work=eMedicine|publisher=Medscape}}&lt;/ref&gt;

Four minor stages of OCD have been identified after trauma. These include [[revascularization]] and formation of granulation (scar) tissue, absorption of necrotic fragments, intertrabecular osteoid deposition, and remodeling of new bone. With delay in the revascularization stage, an OCD lesion develops. A lesion can lead to articular-surface irregularities, which in turn may cause progressive [[arthritis|arthritic]] deterioration.&lt;ref name=&quot;topic57webmd&quot;/&gt;

==Diagnosis==
To diagnose osteochondritis dissecans, an [[X-ray]], [[CT scan]] or [[MRI scan]] can be performed to show necrosis of subchondral bone, formation of loose fragments, or both.&lt;ref name=&quot;pmid12591666&quot;&gt;{{cite journal | vauthors = Boutin RD, Januario JA, Newberg AH, Gundry CR, Newman JS | title = MR imaging features of osteochondritis dissecans of the femoral sulcus | journal = AJR. American Journal of Roentgenology | volume = 180 | issue = 3 | pages = 641–5 | date = March 2003 | pmid = 12591666 | doi = 10.2214/ajr.180.3.1800641 | url = http://www.ajronline.org/cgi/reprint/180/3/641.pdf | url-status = dead | archive-url = https://wayback.archive-it.org/all/20090318145650/http://www.ajronline.org/cgi/reprint/180/3/641.pdf | archive-date = 18 March 2009 }}&lt;/ref&gt; Occasionally a [[nuclear medicine]] [[bone scan]] is used to assess the degree of loosening within the joint.&lt;ref&gt;{{cite journal | vauthors = Mesgarzadeh M, Sapega AA, Bonakdarpour A, Revesz G, Moyer RA, Maurer AH, Alburger PD | title = Osteochondritis dissecans: analysis of mechanical stability with radiography, scintigraphy, and MR imaging | journal = Radiology | volume = 165 | issue = 3 | pages = 775–80 | date = December 1987 | pmid = 3685359 | doi = 10.1148/radiology.165.3.3685359 | url = http://radiology.rsnajnls.org/cgi/reprint/165/3/775 | url-access = subscription }}&lt;/ref&gt;

===Physical examination===
Physical examination often begins with examination of the patient's [[Gait (human)|gait]]. In OCD of the knee, people may walk with the involved leg externally rotated in an attempt to avoid [[tibia]]l spine impingement on the [[lateral (anatomy)|lateral]] aspect of the [[Medial condyle of femur|medial condyle of the femur]].&lt;ref name=&quot;pmid8613454&quot;/&gt;

Next, the examining physician may check for weakness of the [[quadriceps]]. This examination may reveal fluid in the joint, tenderness, and crepitus. The [[Wilson test]] is also useful in locating OCD lesions of the [[Lower extremity of femur|femoral condyle]].&lt;ref&gt;{{cite journal | vauthors = Wilson JN | title = A diagnostic sign in osteochondritis DISSECANS OF THE KNEE | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 49 | issue = 3 | pages = 477–80 | date = April 1967 | pmid = 6022357 | doi = 10.2106/00004623-196749030-00006 | url = http://www.ejbjs.org/cgi/reprint/49/3/477.pdf | url-status = dead | archive-url = https://web.archive.org/web/20081029061547/http://www.ejbjs.org/cgi/reprint/49/3/477.pdf | archive-date = 29 October 2008 }}&lt;/ref&gt; The test is performed by slowly extending the knee from 90 degrees, maintaining internal rotation. Pain at 30 degrees of [[flexion]] and relief with tibial external rotation is indicative of OCD.&lt;ref&gt;{{cite journal | vauthors = Conrad JM, Stanitski CL | title = Osteochondritis dissecans: Wilson's sign revisited | journal = The American Journal of Sports Medicine | volume = 31 | issue = 5 | pages = 777–8 | year = 2003 | pmid = 12975201 | doi = 10.1177/03635465030310052301 | s2cid = 41405897 }}&lt;/ref&gt;

Physical examination of a patient with ankle OCD often returns symptoms of joint effusion, [[crepitus]], and diffuse or localized tenderness. Examination often reveals symptoms of generalized joint pain, [[Swelling (medical)|swelling]], and times with limited range of motion. Some with loose body lesions may report catching, locking, or both.&lt;ref name=&quot;cooperwebmd&quot;/&gt; The possibility of microtrauma emphasizes a need for evaluation of biomechanical forces at the knee in a physical examination. As a result, the alignment and rotation of all major joints in the affected extremity is common, as are [[extrinsic]] and intrinsic abnormalities concerning the affected joint, including laxity.&lt;ref&gt;{{cite journal | vauthors = Livesley PJ, Milligan GF | title = Osteochondritis dissecans patellae. Is there a genetic predisposition? | journal = International Orthopaedics | volume = 16 | issue = 2 | pages = 126–9 | date = 29 November 2004 | pmid = 1428308 | doi = 10.1007/BF00180201 | publisher = Springer Berlin / Heidelberg | s2cid = 24221990 }}&lt;/ref&gt;

===Diagnostic imaging===
X-rays show lucency of the [[ossification]] on the anterior aspect of the knee in juvenile patients. In older people, the lesion typically appears as an area of [[Osteosclerosis|osteosclerotic]] bone with a [[radiodensity|radiolucent]] line between the osteochondral defect and the [[epiphysis]]. The visibility of the lesion depends on its location and on the amount of knee [[flexion]] used. Harding described the lateral X-ray as a method to identify the site of an OCD lesion.&lt;ref&gt;{{cite journal | vauthors = Harding WG | title = Diagnosis of ostechondritis dissecans of the femoral condyles: the value of the lateral x-ray view | journal = Clinical Orthopaedics and Related Research | volume = 123 | issue = 123 | pages = 25–6 | date = March–April 1977 | pmid = 852179 | doi = 10.1097/00003086-197703000-00009 | s2cid = 22739728 }}&lt;/ref&gt;

[[Magnetic resonance imaging]] (MRI) is useful for staging OCD lesions, evaluating the integrity of the joint surface, and distinguishing normal variants of bone formation from OCD by showing bone and cartilage [[edema]] in the area of the irregularity. MRI provides information regarding features of the [[articular cartilage]] and bone under the cartilage, including edema, fractures, fluid interfaces, [[Articular cartilage damage|articular]] surface integrity, and fragment displacement.&lt;ref&gt;{{cite journal | vauthors = Dipaola JD, Nelson DW, Colville MR | title = Characterizing osteochondral lesions by magnetic resonance imaging | journal = Arthroscopy | volume = 7 | issue = 1 | pages = 101–4 | year = 1991 | pmid = 2009106 | doi = 10.1016/0749-8063(91)90087-E }}&lt;/ref&gt;&lt;ref name=&quot;pmid2117355&quot;&gt;{{cite journal | vauthors = De Smet AA, Fisher DR, Graf BK, Lange RH | title = Osteochondritis dissecans of the knee: value of MR imaging in determining lesion stability and the presence of articular cartilage defects | journal = AJR. American Journal of Roentgenology | volume = 155 | issue = 3 | pages = 549–53 | date = September 1990 | pmid = 2117355 | doi = 10.2214/ajr.155.3.2117355 }}&lt;/ref&gt; A low T1 and high T2 signal at the fragment interface is seen in active lesions. This indicates an unstable lesion or recent microfractures.&lt;ref name=&quot;pmid12591666&quot;/&gt; While MRI and [[arthroscopy]] have a close correlation, X-ray films tend to be less inductive of similar MRI results.&lt;ref name=&quot;pmid2117355&quot;/&gt;

[[Computed tomography]] (CT) scans and [[Technetium-99m]] [[bone scan]]s are also sometimes used to monitor the progress of treatment. Unlike plain radiographs (X-rays), CT scans and MRI scans can show the exact location and extent of the lesion.&lt;ref&gt;{{cite journal | vauthors = Bui-Mansfield LT, Kline M, Chew FS, Rogers LF, Lenchik L | title = Osteochondritis dissecans of the tibial plafond: imaging characteristics and a review of the literature | journal = AJR. American Journal of Roentgenology | volume = 175 | issue = 5 | pages = 1305–8 | date = November 2000 | pmid = 11044029 | doi = 10.2214/ajr.175.5.1751305 }}&lt;/ref&gt; Technetium bone scans can detect regional blood flow and the amount of [[osseous]] uptake. Both of these seem to be closely correlated to the potential for healing in the fragment.&lt;ref&gt;{{cite journal | vauthors = Cahill BR, Berg BC | title = 99m-Technetium phosphate compound joint scintigraphy in the management of juvenile osteochondritis dissecans of the femoral condyles | journal = The American Journal of Sports Medicine | volume = 11 | issue = 5 | pages = 329–35 | year = 1983 | pmid = 6638247 | doi = 10.1177/036354658301100509 | s2cid = 41757489 }}&lt;/ref&gt;&lt;ref&gt;{{cite web|url=http://www.eorthopod.com/public/files/Adolescent_Osteochondritis_Dissecans_of_the_Elbow.pdf|archive-url=https://web.archive.org/web/20071027030205/http://www.eorthopod.com/public/files/Adolescent_Osteochondritis_Dissecans_of_the_Elbow.pdf|archive-date=27 October 2007|title=Adolescent Osteochondritis Dissecans of the Elbow|access-date=2 October 2008|author=eOrthopod.com|publisher=Medical Multimedia Group, LLC}}&lt;/ref&gt;
&lt;gallery&gt;
File:CT and projectional radiography of osteochondritis dissecans - annotated.jpg|[[CT scan]] and [[projectional radiography]] of a case of osteochondritis dissecans of parts of the superior-medial [[talus bone|talus]].
File:OCD WalterReed MRI-Sagital-T1.jpeg|[[Sagittal plane|Sagittal MRI]]: Linear low [[Relaxation (NMR)|T1]] signal at the articular surfaces of the [[Anatomical terms of location|lateral]] aspects of the [[Medial condyle of femur|medial condyle of the femur]] confirms the presence of OCD.
File:OCD WalterReed MRI-Sagital-T2.jpeg|Sagittal MRI: High [[Relaxation (NMR)|T2]] signal at the articular surfaces of the lateral aspect of the medial femoral condyle confirms the presence of OCD. Diffuse increase in T2 signal at the medial femoral condyle indicates [[Bone marrow|marrow]] [[edema]].
&lt;/gallery&gt;

===Classification===
OCD is classified by the progression of the disease in stages.
There are two main staging classifications used; one is determined by MRI diagnostic imaging while the other is determined [[Arthroscope|arthroscopically]]. Both stagings represent the pathological conditions associated with OCD's natural progression.&lt;ref name=&quot;pmid10643956&quot;/&gt;

While the arthroscopic classification of bone and cartilage lesions is considered standard, the Anderson MRI staging is the main form of staging used in this article.&lt;ref&gt;{{cite journal | vauthors = Takahara M, Ogino T, Takagi M, Tsuchida H, Orui H, Nambu T | title = Natural progression of osteochondritis dissecans of the humeral capitellum: initial observations | journal = Radiology | volume = 216 | issue = 1 | pages = 207–12 | date = July 2000 | pmid = 10887249 | doi = 10.1148/radiology.216.1.r00jl29207 }}&lt;/ref&gt; Stages&amp;nbsp;I and II are stable lesions. Stages&amp;nbsp;III and IV describe unstable lesions in which a lesion of the cartilage has allowed [[synovial fluid]] between the fragment and bone.

{| class=&quot;wikitable&quot;
|+ '''MRI staging of osteochondritis dissecans'''&lt;ref name=&quot;pmid10643956&quot;/&gt;
! Stage
! Evaluation
! Findings
|-
| I
| Stable
| Articular cartilage thickening
|-
| II
| Stable
| The articular cartilage is breached; low signal behind the fragment indicates fibrous attachment
|-
| III
| Unstable
| The articular cartilage is breached; high signal behind the fragment indicates loss of attachment
|-
| IV
| Unstable
| Formation of loose bodies
|}

{| class=&quot;wikitable&quot;
|+ '''Cheng [[arthroscopy|arthroscopic]] staging of osteochondritis dissecans'''&lt;ref&gt;{{cite conference|vauthors=Cheng MS, Ferkel RD, Applegate GR | title=Osteochondral lesion of the talus: A radiologic and surgical comparison |location=New Orleans, LA |year=1995 |conference=Annual Meeting of the Academy of Orthopaedic Surgeons}}&lt;/ref&gt;
! Grade
! Findings
|-
| A
| Articular cartilage is smooth and intact but may be soft or ballottable
|-
| B
| Articular cartilage has a rough surface
|-
| C
| Articular cartilage has fibrillations or fissures
|-
| D
| Articular cartilage with a flap or exposed bone
|-
| E
| Loose, nondisplaced osteochondral fragment
|-
| F
| Displaced osteochondral fragment
|}

==Treatment==
{{see also|Knee cartilage replacement therapy}}
Treatment options include modified activity with or without weight bearing; immobilization; [[Cryotherapy (chamber therapy)|cryotherapy]]; [[non-steroidal anti-inflammatory drug|anti-inflammatory medication]]; drilling of subchondral bone; [[Microfracture surgery|microfracture]]; removal or reattachment of loose bodies; mosaicplasty and osteoarticular transfer system (OATS) procedures.&lt;ref name=&quot;pmid16794036&quot;/&gt;&lt;ref&gt;{{cite journal | vauthors = Kish G, Módis L, Hangody L | title = Osteochondral mosaicplasty for the treatment of focal chondral and osteochondral lesions of the knee and talus in the athlete. Rationale, indications, techniques, and results | journal = Clinics in Sports Medicine | volume = 18 | issue = 1 | pages = 45–66, vi | date = January 1999 | pmid = 10028116 | doi = 10.1016/S0278-5919(05)70129-0 }}&lt;/ref&gt; The primary goals of treatment are:&lt;ref name=&quot;pmid13438964&quot;&gt;{{cite journal | vauthors = Smillie IS | title = Treatment of osteochondritis dissecans | journal = The Journal of Bone and Joint Surgery. British Volume | volume = 39-B | issue = 2 | pages = 248–60 | date = May 1957 | pmid = 13438964 | doi = 10.1302/0301-620X.39B2.248 | url = http://www.jbjs.org.uk/cgi/reprint/39-B/2/248.pdf | url-status = dead | archive-url = https://web.archive.org/web/20081029061544/http://www.jbjs.org.uk/cgi/reprint/39-B/2/248.pdf | archive-date = 29 October 2008 }}&lt;/ref&gt;
# Enhance the healing potential of subchondral bone;
# Fix unstable fragments while maintaining joint congruity; and
# Replace damaged bone and cartilage with implanted tissues or cells that can grow cartilage.
The articular cartilage's capacity for repair is limited:&lt;ref&gt;{{cite journal | vauthors = Moriya T, Wada Y, Watanabe A, Sasho T, Nakagawa K, Mainil-Varlet P, Moriya H | title = Evaluation of reparative cartilage after autologous chondrocyte implantation for osteochondritis dissecans: histology, biochemistry, and MR imaging | journal = Journal of Orthopaedic Science | volume = 12 | issue = 3 | pages = 265–73 | date = May 2007 | pmid = 17530379 | doi = 10.1007/s00776-007-1111-8 | s2cid = 25130862 }}&lt;/ref&gt; partial-thickness defects in the articular cartilage do not heal spontaneously, and injuries of the articular cartilage that fail to penetrate subchondral bone tend to lead to deterioration of the articular surface.&lt;ref&gt;{{cite web|url=http://www.medscape.com/viewarticle/420393|title=Autologous chondrocyte transplantation|access-date=17 September 2008|author=Bobic V|year=2000|publisher=Medscape}}&lt;/ref&gt; As a result, surgery is often required in even moderate cases where the osteochondral fragment has not detached from the bone (Anderson Stage&amp;nbsp;II, III).&lt;ref name=&quot;orthogateKNEEOCD&quot;/&gt;

===Non-surgical===
Candidates for non-operative treatment are limited to skeletally immature teenagers with a relatively small, intact lesion and the absence of loose bodies. Non-operative management may include activity modification, protected weight bearing (partial or non-weight bearing), and immobilization. The goal of non-operative intervention is to promote healing in the subchondral bone and prevent potential chondral collapse, subsequent fracture, and crater formation.&lt;ref name=&quot;pmid13438964&quot;/&gt;

Once candidates for treatment have been screened, treatment proceeds according to the lesion's location. For example, those with OCD of the knee are immobilized for four to six weeks or even up to six months in [[Extension (kinesiology)|extension]] to remove shear stress from the involved area.&lt;ref&gt;{{cite web|url=http://www.sofop.org/data/Upload/Images/file/POSNA%20Curriculum/2.8.5%20osteochondritisDissecansLower.pdf|title=Osteochondritis dissecans|access-date=21 November 2008|publisher=Société Française d'Orthopédie Pédiatrique|archive-date=18 January 2017|archive-url=https://web.archive.org/web/20170118135111/http://www.sofop.org/data/Upload/Images/file/POSNA%20Curriculum/2.8.5%20osteochondritisDissecansLower.pdf|url-status=dead}}&lt;/ref&gt; They are permitted to walk with weight bearing as tolerated. X-rays are usually taken three months after the start of non-operative therapy; if they reveal that the lesion has healed, a gradual return to activities is instituted.&lt;ref name=&quot;orthogateKNEEOCD&quot;/&gt;&lt;ref&gt;{{cite web|url=http://www.cedars-sinai.edu/12907.html|title=Treating osteochondritis dissecans|access-date=22 November 2008|publisher=Cedars-Sinai Health|url-status=dead|archive-url=https://web.archive.org/web/20081212014412/http://www.cedars-sinai.edu/12907.html|archive-date=12 December 2008}}&lt;/ref&gt; Those demonstrating healing by increased [[radiodensity]] in the subchondral region, or those whose lesions are unchanged, are candidates to repeat the above described three-month protocol until healing is noted.&lt;ref name=&quot;pmid17980849&quot;/&gt;

===Surgery===
[[File:OATS-Arthroscopic Scan1.jpg|thumb|Arthroscopic image of OATS surgery on the [[medial condyle of femur|medial femoral condyle]] of the knee]]
The choice of surgical versus non-surgical treatments for osteochondritis dissecans is controversial.&lt;ref&gt;{{cite journal | vauthors = Nobuta S, Ogawa K, Sato K, Nakagawa T, Hatori M, Itoi E | title = Clinical outcome of fragment fixation for osteochondritis dissecans of the elbow | journal = Upsala Journal of Medical Sciences | volume = 113 | issue = 2 | pages = 201–8 | year = 2008 | pmid = 18509814 | doi = 10.3109/2000-1967-232 | s2cid = 26460111 | url = http://www.diva-portal.org/diva/getDocument?urn_nbn_se_pub_diva-232-2__fulltext.pdf | doi-access = free }}&lt;/ref&gt; Consequently, the type and extent of surgery necessary varies based on patient age, severity of the lesion, and personal bias of the treating surgeon—entailing an exhaustive list of suggested treatments. A variety of surgical options exist for the treatment of persistently symptomatic, intact, partially detached, and completely detached OCD lesions. Post-surgery reparative cartilage is inferior to healthy [[hyaline]] cartilage in [[glycosaminoglycan]] concentration, [[Histology|histological]], and [[Immunohistochemistry|immunohistochemical]] appearance.&lt;ref&gt;{{cite journal | vauthors = LaPrade RF, Bursch LS, Olson EJ, Havlas V, Carlson CS | title = Histologic and immunohistochemical characteristics of failed articular cartilage resurfacing procedures for osteochondritis of the knee: a case series | journal = The American Journal of Sports Medicine | volume = 36 | issue = 2 | pages = 360–8 | date = February 2008 | pmid = 18006675 | doi = 10.1177/0363546507308359 | s2cid = 2360001 }}&lt;/ref&gt; As a result, surgery is often avoided if non-operative treatment is viable.

====Intact lesions====
If non-surgical measures are unsuccessful, drilling may be considered to stimulate healing of the subchondral bone. [[Arthroscopic]] drilling may be performed by using an antegrade (from the front) approach from the joint space through the articular cartilage, or by using a retrograde (from behind) approach through the bone outside of the joint to avoid penetration of the articular cartilage. This has proven successful with positive results at one-year follow-up with antegrade drilling in nine out of eleven teenagers with the juvenile form of OCD,&lt;ref&gt;{{cite journal | vauthors = Bradley J, Dandy DJ | title = Results of drilling osteochondritis dissecans before skeletal maturity | journal = The Journal of Bone and Joint Surgery. British Volume | volume = 71 | issue = 4 | pages = 642–4 | date = August 1989 | pmid = 2768313 | doi = 10.1302/0301-620X.71B4.2768313 | doi-access = free }}&lt;/ref&gt; and in 18 of 20 skeletally immature people (follow-up of five years) who had failed prior conservative programs.&lt;ref&gt;{{cite journal | vauthors = Anderson AF, Richards DB, Pagnani MJ, Hovis WD | title = Antegrade drilling for osteochondritis dissecans of the knee | journal = Arthroscopy | volume = 13 | issue = 3 | pages = 319–24 | date = June 1997 | pmid = 9195028 | doi = 10.1016/S0749-8063(97)90028-1 }}&lt;/ref&gt;

====Hinged lesions====
Pins and screws can be used to secure flap (sometimes referred to as hinged) lesions.&lt;ref&gt;{{cite journal | vauthors = Johnson LL, Uitvlugt G, Austin MD, Detrisac DA, Johnson C | title = Osteochondritis dissecans of the knee: arthroscopic compression screw fixation | journal = Arthroscopy | volume = 6 | issue = 3 | pages = 179–89 | year = 1990 | pmid = 2206180 | doi = 10.1016/0749-8063(90)90073-M }}&lt;/ref&gt; Bone pegs, metallic pins and screws, and other bioresorbable screws may be used to secure these types of lesions.&lt;ref&gt;{{cite journal | vauthors = Thomson NL | title = Osteochondritis dissecans and osteochondral fragments managed by Herbert compression screw fixation | journal = Clinical Orthopaedics and Related Research | issue = 224 | pages = 71–8 | date = November 1987 | volume = 224 | pmid = 3665256 | doi = 10.1097/00003086-198711000-00010 }}&lt;/ref&gt;

====Full thickness lesions====
{{multiple image | direction = vertical
| width = 220
| image1 = Paste Graft Surgery-1.jpg|caption1 = Morselization of the articular cartilage lesion
| image2 = Paste Graft Surgery-2.jpg|caption2 = Harvesting of the articular cartilage and bone
| image3 = Paste Graft Surgery-3.jpg|caption3 = Manual crushing used to make a paste graft
| image4 = Paste Graft Surgery-4.jpg|caption4 = Impacting the paste graft into the morselized defect
}}

The three methods most commonly used in treating full thickness lesions are arthroscopic drilling, abrasion, and microfracturing.

In 1946, Magnusson established the use of stem cells from [[bone marrow]] with the first surgical [[debridement]] of an OCD lesion. These cells typically differentiate into [[fibrocartilage]] and rarely form hyaline cartilage. While small lesions can be resurfaced using this form of surgery, the repair tissue tends to have less strength than normal [[hyaline cartilage]] and must be protected for 6 to 12 months. Results for large lesions tend to diminish over time; this can be attributed to the decreased resilience and poor wear characteristics of the fibrocartilage.&lt;ref&gt;{{cite journal | vauthors = Mandelbaum BR, Browne JE, Fu F, Micheli L, Mosely JB, Erggelet C, Minas T, Peterson L | title = Articular cartilage lesions of the knee | journal = The American Journal of Sports Medicine | volume = 26 | issue = 6 | pages = 853–61 | year = 1998 | pmid = 9850792 | doi = 10.1177/03635465980260062201 | s2cid = 21318642 }}&lt;/ref&gt;

In attempts to address the weaker structure of the reparative fibrocartilage, new techniques have been designed to fill the defect with tissue that more closely simulates normal hyaline articular cartilage. One such technique is [[autologous]] [[chondrocyte]] implantation (ACI), which is useful for large, isolated [[femur|femoral]] defects in younger people. In this surgery, chondrocytes are arthroscopically extracted from the [[Intercondylar fossa of femur|intercondylar notch]] of the articular surface. The chondrocytes are grown and injected into the defect under a periosteal patch. ACI surgery has reported good to excellent results for reduced swelling, pain and locking in clinical follow-up examinations.&lt;ref&gt;{{cite journal | vauthors = Brittberg M, Lindahl A, Nilsson A, Ohlsson C, Isaksson O, Peterson L | title = Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation | journal = The New England Journal of Medicine | volume = 331 | issue = 14 | pages = 889–95 | date = October 1994 | pmid = 8078550 | doi = 10.1056/NEJM199410063311401 | doi-access = free }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Peterson L, Minas T, Brittberg M, Nilsson A, Sjögren-Jansson E, Lindahl A | title = Two- to 9-year outcome after autologous chondrocyte transplantation of the knee | journal = Clinical Orthopaedics and Related Research | volume = 374 | issue = 374 | pages = 212–34 | date = May 2000 | pmid = 10818982 | doi = 10.1097/00003086-200005000-00020 | s2cid = 25408760 }}&lt;/ref&gt; Some physicians preferred to use undifferentiated pluripotential cells, such as periosteal cells and bone marrow stem cells, as opposed to chondrocytes. These too have demonstrated the ability to regenerate both the cartilage and the underlying subchondral bone.&lt;ref&gt;{{cite journal | vauthors = O'Driscoll SW | title = The healing and regeneration of articular cartilage | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 80 | issue = 12 | pages = 1795–812 | date = December 1998 | pmid = 9875939 | doi = 10.2106/00004623-199812000-00011 | url = http://www.ejbjs.org/cgi/reprint/80/12/1795.pdf | url-status = dead | archive-url = https://web.archive.org/web/20081029061541/http://www.ejbjs.org/cgi/reprint/80/12/1795.pdf | archive-date = 29 October 2008 }}&lt;/ref&gt;

Similar to OATS, arthroscopic articular cartilage paste grafting is a surgical procedure offering cost-effective, long-lasting results for stage IV lesions. A bone and cartilage paste derived from crushed plugs of the non-weight-bearing intercondylar notch can achieve pain relief, repair damaged tissue, and restore function.&lt;ref&gt;{{cite journal | vauthors = Stone KR, Walgenbach AW, Freyer A, Turek TJ, Speer DP | title = Articular cartilage paste grafting to full-thickness articular cartilage knee joint lesions: a 2- to 12-year follow-up | journal = Arthroscopy | volume = 22 | issue = 3 | pages = 291–9 | date = March 2006 | pmid = 16517314 | doi = 10.1016/j.arthro.2005.12.051 }}&lt;/ref&gt;

====Unstable lesions====
Some methods of fixation for unstable lesions include countersunk compression screws and [[Timothy Herbert|Herbert screws]] or pins made of stainless steel or materials that can be absorbed by the body.&lt;ref&gt;{{cite journal | vauthors = Kocher MS, Czarnecki JJ, Andersen JS, Micheli LJ | title = Internal fixation of juvenile osteochondritis dissecans lesions of the knee | journal = The American Journal of Sports Medicine | volume = 35 | issue = 5 | pages = 712–8 | date = May 2007 | pmid = 17337729 | doi = 10.1177/0363546506296608 | s2cid = 13150540 }}&lt;/ref&gt; If loose bodies are found, they are removed. Although each case is unique and treatment is chosen on an individual basis, ACI is generally performed on large defects in skeletally mature people.

====Rehabilitation====
Continuous passive motion (CPM) has been used to improve healing of the articular surface during the postoperative period for people with full-thickness lesions. It has been shown to promote articular cartilage healing for small (&lt; 3&amp;nbsp;mm in diameter) lesions in rabbits.&lt;ref&gt;{{cite journal | vauthors = Salter RB, Simmonds DF, Malcolm BW, Rumble EJ, MacMichael D, Clements ND | title = The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage. An experimental investigation in the rabbit | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 62 | issue = 8 | pages = 1232–51 | date = December 1980 | pmid = 7440603 | doi = 10.2106/00004623-198062080-00002 | url = http://www.ejbjs.org/cgi/reprint/62/8/1232.pdf | url-status = dead | archive-url = https://web.archive.org/web/20090318145705/http://www.ejbjs.org/cgi/reprint/62/8/1232.pdf | archive-date = 18 March 2009 }}&lt;/ref&gt; Similarly, Rodrigo and Steadman reported that CPM for six hours per day for eight weeks produced an improved clinical outcome in humans.&lt;ref&gt;{{cite journal | vauthors = Rodrigo JJ, Steadman JR, Syftestad G, Benton H, Silliman J | title = Effects of human knee synovial fluid on chondrogenesis in vitro | journal = The American Journal of Knee Surgery | volume = 8 | issue = 4 | pages = 124–9 | year = 1995 | pmid = 8590122 }}&lt;/ref&gt;

A rehabilitation program often involves protection of the compromised articular surface and underlying subchondral bone combined with maintenance of strength and range of motion. Post-operative [[analgesics]], namely a mix of [[opioids]] and [[NSAIDs]], are usually required to control pain, inflammation and swelling.&lt;ref&gt;{{cite web|url=http://emedicine.medscape.com/article/89718-treatment|title=Knee Osteochondritis dissecans: treatment &amp; medication |access-date=14 February 2009|vauthors=Jacobs B, Ertl JP, Kovacs G, Jacobs JA |date=28 July 2006|work=eMedicine |publisher=Medscape}}&lt;/ref&gt; Straight leg raising and other [[isometric exercise]]s are encouraged during the post-operative or immobilization period. A six to eight-week home or formal [[physical therapy]] program is usually instituted once the immobilization period has ended, incorporating range of motion, stretching, progressive strengthening, and functional or sport-specific training. During this time, patients are advised to avoid running and jumping, but are permitted to perform low impact activities, such as walking or swimming. If patients return to activity before the cartilage has become firm, they will typically complain of pain during maneuvers such as squatting or jumping.&lt;ref name=&quot;orthogateKNEEOCD&quot;&gt;{{cite web |url=http://www.orthogate.org/index2.php?option=com_content&amp;do_pdf=1&amp;id=185 |title=Osteochondritis dissecans of the knee |access-date=16 November 2008 |date=28 July 2006 |format=PDF |publisher=Orthogate |archive-date=1 July 2016 |archive-url=https://web.archive.org/web/20160701024800/http://www.orthogate.org/index2.php?option=com_content&amp;do_pdf=1&amp;id=185 |url-status=dead }}&lt;/ref&gt;

==Prognosis==
The prognosis after different treatments varies and is based on several factors that include the age of the patient, the affected joint, the stage of the lesion and, most importantly, the state of the growth plate.&lt;ref name=&quot;cooperwebmd&quot;&gt;{{cite web|url=http://www.emedicine.com/orthoped/topic639.htm|title=Definition of osteochondritis dissecans|access-date=18 September 2008|vauthors=Cooper G, Russell W |work=eMedicine|publisher=Medscape}}&lt;/ref&gt; It follows that the two main forms of osteochondritis dissecans are defined by skeletal maturity. The juvenile form of the disease occurs in open growth plates, usually affecting children between the ages of 5 and 15 years.&lt;ref&gt;{{cite book|vauthors=Fleisher GR, Ludwig S, Henretig FM, Ruddy RM, Silverman BK |year=2005|title=Textbook of Pediatric Emergency Medicine|publisher=Lippincott Williams &amp; Wilkins|isbn=0-7817-5074-1|url=https://books.google.com/books?id=oA7qSOvYZxUC&amp;q=free+ebook+osteochondritis&amp;pg=RA2-PA1703|page=1703}}&lt;/ref&gt; The adult form commonly occurs between ages 16 to 50, although it is unclear whether these adults developed the disease after skeletal maturity or were undiagnosed as children.&lt;ref&gt;{{cite book|vauthors=Simon RR, Sherman SC, Koenigsknecht SJ |year=2006|title=Emergency Orthopedics: The Extremities|publisher=McGraw-Hill Professional|isbn=0-07-144831-4|url=https://books.google.com/books?id=nMXRDsufkMwC&amp;q=osteochondritis+dissecans&amp;pg=PA254|page=254}}&lt;/ref&gt;

The prognosis is good for stable lesions (stage&amp;nbsp;I and II) in juveniles with open growth plates; treated conservatively—typically without surgery—50% of cases will heal.&lt;ref&gt;{{cite journal | vauthors = Cahill BR | title = Osteochondritis Dissecans of the Knee: Treatment of Juvenile and Adult Forms | journal = The Journal of the American Academy of Orthopaedic Surgeons | volume = 3 | issue = 4 | pages = 237–247 | date = July 1995 | pmid = 10795030 | doi = 10.5435/00124635-199507000-00006 | s2cid = 27786111 }}&lt;/ref&gt; Recovery in juveniles can be attributed to the bone's ability to repair damaged or dead bone tissue and cartilage in a process called bone remodeling. Open growth plates are characterized by increased numbers of undifferentiated chondrocytes ([[Mesenchymal stem cell|stem cells]]), which are precursors to both bone and cartilaginous tissue. As a result, open growth plates allow for more of the stem cells necessary for repair in the affected joint.&lt;ref&gt;{{cite book |author=Bogin B|title=Patterns of Human Growth|url=https://books.google.com/books?id=ScfPjwF3BngC|access-date=20 February 2009|edition=2|date=January 2008|publisher=Cambridge University Press|isbn=978-0-521-56438-0|page=102|chapter=Mammalian Growth|chapter-url=https://books.google.com/books?id=ScfPjwF3BngC&amp;q=growth+plates+bone+remodeling&amp;pg=PA102}}&lt;/ref&gt; Unstable, large, full-thickness lesions (stage&amp;nbsp;III and IV) or lesions of any stage found in the skeletally mature are more likely to fail non-operative treatment. These lesions offer a worse prognosis and surgery is required in most cases.&lt;ref name=&quot;pmid2722949&quot;/&gt;&lt;ref&gt;{{cite journal | vauthors = Lützner J, Mettelsiefen J, Günther KP, Thielemann F | title = [Treatment of osteochondritis dissecans of the knee joint] | language = de | journal = Der Orthopade | volume = 36 | issue = 9 | pages = 871–9; quiz 880 | date = September 2007 | pmid = 17680233 | doi = 10.1007/s00132-007-1130-3 | s2cid = 21394644 }}&lt;/ref&gt;

==Epidemiology==
OCD is a relatively rare disorder, with an estimated [[incidence (epidemiology)|incidence]] of 15 to 30 cases per 100,000 persons per year.&lt;ref name=&quot;pmid9012566&quot;&gt;{{cite journal | vauthors = Obedian RS, Grelsamer RP | title = Osteochondritis dissecans of the distal femur and patella | journal = Clinics in Sports Medicine | volume = 16 | issue = 1 | pages = 157–74 | date = January 1997 | pmid = 9012566 | doi = 10.1016/S0278-5919(05)70012-0 | doi-access = free }}&lt;/ref&gt; Widuchowski W ''et al.'' found OCD to be the cause of articular cartilage defects in 2% of cases in a study of 25,124 knee arthroscopies.&lt;ref&gt;{{cite journal | vauthors = Widuchowski W, Widuchowski J, Trzaska T | title = Articular cartilage defects: study of 25,124 knee arthroscopies | journal = The Knee | volume = 14 | issue = 3 | pages = 177–82 | date = June 2007 | pmid = 17428666 | doi = 10.1016/j.knee.2007.02.001 }}&lt;/ref&gt; Although rare, OCD is noted as an important cause of joint pain in active adolescents. The juvenile form of the disease occurs in children with open growth plates, usually between the ages 5 and 15 years and occurs more commonly in males than females, with a ratio between 2:1 and 3:1.&lt;ref name=&quot;pmid6807595&quot;/&gt;&lt;ref&gt;{{cite journal|author=Nagura S|title=The so-called osteochondritis dissecans of Konig|journal=Clinical Orthopaedics and Related Research|volume=18|pages=100–121|year=1960}}&lt;/ref&gt; OCD has become more common among adolescent females as they become more active in sports.&lt;ref&gt;{{cite journal | vauthors = Williamson LR, Albright JP | title = Bilateral osteochondritis dissecans of the elbow in a female pitcher | journal = The Journal of Family Practice | volume = 43 | issue = 5 | pages = 489–93 | date = November 1996 | pmid = 8917149 }}&lt;/ref&gt; The adult form, which occurs in those who have reached skeletal maturity, is most commonly found in people 16 to 50 years old.&lt;ref name=&quot;pmid2722949&quot;&gt;{{cite journal | vauthors = Bradley J, Dandy DJ | title = Osteochondritis dissecans and other lesions of the femoral condyles | journal = The Journal of Bone and Joint Surgery. British Volume | volume = 71 | issue = 3 | pages = 518–22 | date = May 1989 | pmid = 2722949 | doi = 10.1302/0301-620X.71B3.2722949 | doi-access = free }}&lt;/ref&gt;

While OCD may affect any joint, the knee—specifically the [[Medial condyle of femur|medial femoral condyle]] in 75–85% of knee cases—tends to be the most commonly affected, and constitutes 75% of all cases.&lt;ref name=&quot;pmid6807595&quot;/&gt;&lt;ref&gt;{{cite journal | vauthors = Hughston JC, Hergenroeder PT, Courtenay BG | title = Osteochondritis dissecans of the femoral condyles | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 66 | issue = 9 | pages = 1340–8 | date = December 1984 | pmid = 6501330 | doi = 10.2106/00004623-198466090-00003 | url = http://www.ejbjs.org/cgi/reprint/66/9/1340.pdf | url-status = dead | archive-url = https://web.archive.org/web/20081029061544/http://www.ejbjs.org/cgi/reprint/66/9/1340.pdf | archive-date = 29 October 2008 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Aichroth P | title = Osteochondritis dissecans of the knee. A clinical survey | journal = The Journal of Bone and Joint Surgery. British Volume | volume = 53 | issue = 3 | pages = 440–7 | date = August 1971 | pmid = 5562371 | doi = 10.1302/0301-620X.53B3.440 | url = http://www.jbjs.org.uk/cgi/reprint/53-B/3/440.pdf | url-status = dead | archive-url = https://web.archive.org/web/20081029061544/http://www.jbjs.org.uk/cgi/reprint/53-B/3/440.pdf | archive-date = 29 October 2008 }}&lt;/ref&gt;&lt;ref&gt;{{cite journal | vauthors = Lindén B | title = The incidence of osteochondritis dissecans in the condyles of the femur | journal = Acta Orthopaedica Scandinavica | volume = 47 | issue = 6 | pages = 664–7 | date = December 1976 | pmid = 1015263 | doi = 10.3109/17453677608988756 | doi-access =  }}&lt;/ref&gt; The elbow (specifically the [[capitulum of the humerus]]) is the second most affected joint with 6% of cases; the [[Talus bone|talar dome]] of the ankle represents 4% of cases.&lt;ref&gt;{{cite web|url=http://www.emedicine.com/orthoped/topic639.htm|title=Osteochondritis Dissecans|access-date=16 November 2008|vauthors=Cooper G, Warren R |date=15 May 2008|work=eMedicine|publisher=Medscape}}&lt;/ref&gt; Less frequent locations include the [[patella]], [[vertebrae]], the femoral head, and the [[glenoid]] of the scapula.&lt;ref&gt;{{cite journal | vauthors = Tuite MJ, DeSmet AA | title = MRI of selected sports injuries: muscle tears, groin pain, and osteochondritis dissecans | journal = Seminars in Ultrasound, CT and MRI | volume = 15 | issue = 5 | pages = 318–40 | date = October 1994 | pmid = 7803070 | doi = 10.1016/S0887-2171(05)80002-2 }}&lt;/ref&gt;

The oldest case of OCD was identified on the temporo-mandibular joint of the Qafzeh 9 fossil.&lt;ref&gt;{{cite journal | vauthors = Coutinho Nogueira D, Dutour O, Coqueugniot H, Tillier AM | title = Qafzeh 9 mandible (ca 90-100 kyrs BP, Israel) revisited: μ-CT and 3D reveal new pathological conditions | journal = International Journal of Paleopathology | volume = 26 | pages = 104–110 | date = September 2019 | pmid = 31351220 | doi = 10.1016/j.ijpp.2019.06.002 | url = https://hal.archives-ouvertes.fr/hal-02266401/file/Coutinho%20Nogueira%20et%20al.%202019%20mandibule.pdf | doi-access = free }}&lt;/ref&gt;

==History==
The condition was initially described by [[Alexander Monro (primus)]] in 1738.&lt;ref&gt;{{cite journal|journal=Medical Essays and Observations |title=Part of the cartilage of the joint separated and ossified|author=Munro A|year=1738 |volume=4|page=19}} cited in {{cite journal | vauthors = Burr RC | title = Osteochondritis Dissecans | journal = Canadian Medical Association Journal | volume = 41 | issue = 3 | pages = 232–5 | date = September 1939 | pmid = 20321457 | pmc = 537458 }}&lt;/ref&gt;
In 1870, [[James Paget]] described the disease process for the first time, but it was not until 1887 that [[Franz König (surgeon)|Franz König]] published a paper on the cause of loose bodies in the joint.&lt;ref&gt;{{cite journal | vauthors = Garrett JC | title = Osteochondritis dissecans | journal = Clinics in Sports Medicine | volume = 10 | issue = 3 | pages = 569–93 | date = July 1991 | doi = 10.1016/S0278-5919(20)30610-4 | pmid = 1868560 }}&lt;/ref&gt; In his paper, König concluded that:&lt;ref&gt;{{cite journal|author=König F|title=Uber freie Korper in den Gelenken|journal=Deutsche Zeitschrift für Chirurgie |volume=27|issue=1–2|pages=90–109|date=December 1888|language=de|doi=10.1007/BF02792135|s2cid=40506960|url=https://zenodo.org/record/2390406}}&lt;/ref&gt;
# Trauma had to be very severe to break off parts of the joint surface.
# Less severe trauma might contuse the bone to cause an area of necrosis that might then separate.
# In some cases, the absence of notable trauma made it likely that there existed some spontaneous cause of separation.
König named the disease &quot;osteochondritis dissecans&quot;,&lt;ref&gt;{{cite journal | vauthors = Barrie HJ | title = Osteochondritis dissecans 1887-1987. A centennial look at König's memorable phrase | journal = The Journal of Bone and Joint Surgery. British Volume | volume = 69 | issue = 5 | pages = 693–5 | date = November 1987 | pmid = 3316236 | doi = 10.1302/0301-620X.69B5.3316236 | url = http://www.jbjs.org.uk/cgi/reprint/69-B/5/693.pdf | url-status = dead | archive-url = https://web.archive.org/web/20090318145633/http://www.jbjs.org.uk/cgi/reprint/69-B/5/693.pdf | archive-date = 18 March 2009 }}&lt;/ref&gt; describing it as a subchondral inflammatory process of the knee, resulting in a loose fragment of cartilage from the femoral condyle. In 1922, Kappis described this process in the ankle joint.&lt;ref&gt;{{cite journal|author=Kappis M|title=Weitere beitrage zur traumatisch-mechanischen entstehung der &quot;spontanen&quot; knorpela biosungen|journal=Deutsche Zeitschrift für Chirurgie |volume=171|pages=13–29|year=1922|language=de|doi=10.1007/BF02812921|s2cid=33781294}}&lt;/ref&gt; On review of all literature describing transchondral fractures of the [[Talus bone|talus]], Berndt and Harty developed a classification system for staging of osteochondral lesions of the talus (OLTs).&lt;ref&gt;{{cite journal | vauthors = Berndt AL, Harty M | title = Transchondral fractures (osteochondritis dissecans) of the talus | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 86 | issue = 6 | pages = 1336 | date = June 2004 | pmid = 15173311 | doi = 10.2106/00004623-200406000-00032 }}&lt;/ref&gt; The term osteochondritis dissecans has persisted, and has since been broadened to describe a similar process occurring in many other joints, including the knee, hip, elbow, and [[Metatarsophalangeal articulations|metatarsophalangeal joints]].&lt;ref&gt;{{cite book|author=Morrey BF|year=2000|title=The Elbow and Its Disorders|place=Philadelphia, PA|publisher= W.B. Saunders|isbn=0-7216-7752-5|pages=250–60}}&lt;/ref&gt;&lt;ref&gt;{{cite book|vauthors=Walzer J, Pappas AM |year=1995|title=Upper Extremity Injuries in the Athlete|url=https://archive.org/details/upperextremityin0000unse_h0s4 |url-access=registration |location=Edinburgh, UK|publisher=Churchill Livingstone|isbn=0-443-08836-5|page=[https://archive.org/details/upperextremityin0000unse_h0s4/page/132 132]}}&lt;/ref&gt;

==Notable cases==

*[[Michael Russell (tennis)|Michael Russell]], American tennis player&lt;ref&gt;{{cite news |author=Gene Frenette |url=http://jacksonville.com/tu-online/stories/082906/spl_4698211.shtml |title=Russell takes his last shot |publisher=The Times-Union |date=29 August 2006 |access-date=13 November 2013 |archive-date=19 January 2016 |archive-url=https://web.archive.org/web/20160119031023/http://jacksonville.com/tu-online/stories/082906/spl_4698211.shtml |url-status=dead }}&lt;/ref&gt;
*[[Kristina Vaculik]], Canadian artistic gymnast&lt;ref&gt;{{cite web |url=http://www.gostanford.com/ViewArticle.dbml?DB_OEM_ID=30600&amp;ATCLID=208436997 |title=Kristina Vaculik Bio |publisher=GoStanford.com |access-date=13 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131113045009/http://www.gostanford.com/ViewArticle.dbml?DB_OEM_ID=30600&amp;ATCLID=208436997 |archive-date=13 November 2013 }}&lt;/ref&gt;&lt;ref&gt;{{cite web|url=http://www.intlgymnast.com/index.php?option=com_content&amp;view=article&amp;id=1310:ig-online-interview-kristina-vaculik-canada&amp;catid=3:interviews&amp;Itemid=56 |title=Interview: Kristina Vaculik (Canada) |publisher=International Gymnast Magazine |date=24 January 2010 |access-date=13 November 2013}}&lt;/ref&gt;&lt;ref&gt;{{cite news|author=Beverley Smith |url=https://www.theglobeandmail.com/sports/more-sports/olympics-in-vaculiks-sights/article1211474/ |title=Olympics in Vaculik's sights |newspaper=The Globe and Mail |date=28 May 2010 |access-date=13 November 2013}}&lt;/ref&gt; 
*[[Jonathan Vilma]], American football linebacker&lt;ref&gt;{{cite web|url=http://www.nydailynews.com/sports/football/jets/jets-knew-jonathan-vilma-knee-injury-04-article-1.259485 |title=Jets knew of Jonathan Vilma's knee injury in '04 |publisher=NY Daily News |date=1 November 2007 |access-date=13 November 2013}}&lt;/ref&gt;&lt;ref&gt;{{cite web |author=Tom Rock |url=http://www.newsday.com/sports/columnists/tom-rock/jets-chalk-talk-vilma-still-secretive-on-injury-1.587081 |title=JETS CHALK TALK: Vilma still secretive on injury |publisher=Newsday |date=13 November 2007 |access-date=13 November 2013 |archive-date=16 July 2021 |archive-url=https://web.archive.org/web/20210716090445/https://www.newsday.com/sports/columnists/tom-rock/jets-chalk-talk-vilma-still-secretive-on-injury-1.587081 |url-status=dead }}&lt;/ref&gt;
*[[Seo In-guk]], Korean actor&lt;ref&gt;{{cite web |title=Seo In Guk exempt from his mandatory military service |url=https://www.sbs.com.au/popasia/blog/2017/06/15/seo-guk-exempt-his-mandatory-military-service |website=SBS PopAsia |date=15 June 2017 |access-date=5 December 2019 |language=en}}&lt;/ref&gt;&lt;ref&gt;{{cite web |title=Seo In-guk returns after controversial military exemption |url=https://www.koreatimes.co.kr/www/nation/2018/08/688_254134.html |website=koreatimes |access-date=5 December 2019 |language=en |date=20 August 2018}}&lt;/ref&gt;

==Veterinary aspects==
{{main|Elbow dysplasia}}
[[File:Osteochondritis dissecans pathology Danish sow.png|thumb|Pathological specimen from a sow— the arrow points to a fracture in the [[lateral epicondyle of the humerus]].&lt;br /&gt;[[H&amp;E stain|Hematoxylin and eosin staining]]. Bar = 200 [[micrometre|μm]].]]
OCD also is found in animals, and is of particular concern in horses, as there may be a hereditary component in some [[horse breed]]s.&lt;ref&gt;{{cite journal|author=Thomas, Heather Smith|title=Osteochondritis Dissecans in Thoroughbreds. Weanlings: A Field Study |journal=California Thoroughbred |pages=65–67|date=August 2002|url=http://www.ctba.com/02magazine/aug02/HORSECARE.pdf|access-date=9 January 2010|archive-url = https://web.archive.org/web/20061021235616/http://www.ctba.com/02magazine/aug02/HORSECARE.pdf |archive-date = 21 October 2006|url-status=dead}}&lt;/ref&gt; Feeding for forced growth and [[selective breeding]] for increased size are also factors. OCD has also been studied in other animals—mainly dogs, especially the [[German Shepherd Dog|German Shepherd]]&lt;ref name=&quot;Ch.84OCD&quot;/&gt;—where it is a common primary cause of [[elbow dysplasia]] in medium-large breeds.&lt;ref&gt;{{cite web| first1 = Matthew | last1 = Pead | first2 = Sue | last2 = 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=16 July 2010|url-status=dead|archive-url=https://web.archive.org/web/20111002022122/http://www.bva.co.uk/public/documents/chs_elbow.pdf|archive-date=2 October 2011}}&lt;/ref&gt;

In animals, OCD is considered a developmental and metabolic disorder related to cartilage growth and endochondral [[ossification]]. Osteochondritis itself signifies the disturbance of the usual growth process of cartilage, and OCD is the term used when this affects joint cartilage causing a fragment to become loose.&lt;ref&gt;{{cite journal | vauthors = Berzon JL | title = Osteochondritis dissecans in the dog: diagnosis and therapy | journal = Journal of the American Veterinary Medical Association | volume = 175 | issue = 8 | pages = 796–9 | date = October 1979 | pmid = 393676 }}&lt;/ref&gt;

According to the Columbia Animal Hospital the frequency of affected animals is dogs, humans, pigs, horses, cattle, chickens, and turkeys, and in dogs the most commonly affected breeds include the German Shepherd, Golden and Labrador Retriever, Rottweiler, Great Dane, Bernese Mountain Dog, and Saint Bernard.&lt;ref name=&quot;CAH&quot;&gt;{{cite web|title=Osteochondrosis, osteochondritis dissecans (OCD)|url=http://www.petshealthrx.com/encycEntry.cfm?ENTRY=8&amp;COLLECTION=EncycIllness&amp;MODE=full|work=Category: Canine |publisher=Columbia Animal Hospital|date=n.d.|access-date=13 September 2008 |archive-url = https://web.archive.org/web/20050325013242/http://www.petshealthrx.com/encycEntry.cfm?ENTRY=8&amp;COLLECTION=EncycIllness&amp;MODE=full |archive-date = 25 March 2005}}&lt;/ref&gt; Although any joint may be affected, those commonly affected by OCD in the dog are: shoulder (often bilaterally), elbow, knee and [[Hock (zoology)|tarsus]].&lt;ref name=&quot;CAH&quot;/&gt;

The problem develops in puppyhood although often subclinically, and there may be pain or stiffness, discomfort on extension, or other compensating characteristics. Diagnosis generally depends on X-rays, [[arthroscopy]], or [[MRI]] scans. While cases of OCD of the stifle go undetected and heal spontaneously, others are exhibited in acute lameness. Surgery is recommended once the animal has been deemed lame.&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=20 September 2008|archive-url=https://web.archive.org/web/20170703170539/http://cal.vet.upenn.edu/projects/saortho/index.html|archive-date=3 July 2017|url-status=dead}}&lt;/ref&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;

{{Clear}}

== References ==
{{Reflist}}

== External links ==
{{Medical resources
| DiseasesDB = 9320
| ICD10 = {{ICD10|M|93|2|m|91}}
| ICD9 = {{ICD9|732.7}}
| ICDO =
| OMIM = 165800
| MedlinePlus =
| eMedicineSubj = radio
| eMedicineTopic = 495
| eMedicine_mult = {{eMedicine2|sports|57}} {{eMedicine2|orthoped|639}}
| MeshID = D010008
}}
{{commons}}
* [https://web.archive.org/web/20111106111841/http://rad.usuhs.edu/medpix/parent.php3?mode=image_finder#top Radiology] MR and CT of OCD

{{Osteochondropathy}}
{{featured article}}

{{DEFAULTSORT:Osteochondritis Dissecans}}
[[Category:Chondropathies]]
[[Category:Dog musculoskeletal disorders]]
[[Category:Horse diseases]]
[[Category:Inflammations]]
[[Category:Rare diseases]]