Summary Osteochondritis Dissecans is a pathologic lesion affecting articular cartilage and subchondral bone with variable clinical patterns. Diagnosis may be made radiographically (notch view) but MRI usually required to determine size and stability of lesion, and to document the degree of cartilage injury. Treatment may be nonoperative with restricted weight bearing in children with open physis. Surgical treatment may be indicated in older patients (closed physis), lesions that are unstable and patients who have failed conservative management. Epidemiology Demographics juvenile form (open physes) occurs at age 10-15 (median age: 13.1) while the physis is still open adult form (skeletal maturity) Anatomic location knee (most common) posterolateral aspect of medial femoral condyle (70% of lesions in knee) capitellum of humerus talus Etiology Pathophysiology mechanism/etiology may be hereditary traumatic vascular login to view 1 more bullet pathoanatomic cascade softening of the overlying articular cartilage with intact articular surface early articular cartilage separation partial detachment of lesion osteochondral separation with loose bodies Classification Clanton Classification of Osteochondritis (Clanton and DeLee) Type I Depressed osteochondral fracture Type II Fragment attached by osseous bridge Type III Detached non-displaced fragment Type IV Displaced fragment Presentation Symptoms pain activity related pain that is vague and poorly localized mechanical symptoms indicates advanced disease recurrent effusions of the knee Physical exam localized tenderness stiffness swelling Wilson’s test pain with internally rotating the tibia during extension of the knee between 90° and 30°, then relieving the pain with tibial external rotation Imaging Radiographs recommended views weight-bearing anteroposterior, lateral radiographs obtain tunnel (notch) view login to view 1 more bullet MRI useful for characterizing size of lesion status of subchondral bone and cartilage signal intensity surrounding lesion presence of loose bodies Treatment Nonoperative restricted weight bearing and bracing indications login to view 2 more bullets outcomes login to view 1 more bullet Operative diagnostic arthroscopy indications login to view 4 more bullets subchondral drilling with K-wire or drill indications login to view 2 more bullets outcomes login to view 2 more bullets fixation of unstable lesion indications login to view 1 more bullet outcomes login to view 1 more bullet chondral resurfacing indications login to view 1 more bullet knee arthroplasty indications login to view 1 more bullet Techniques Microfracture technique tap awl to a depth of 1-1.5cm below articular surface post-operative NWB for 4-6 weeks with CPM Internal fixation technique options for fixation login to view 4 more bullets cons may require hardware removal Osteochondral grafting arthrotomy (vs. arthroscopy) indicated in lesions > 3cm technique login to view 5 more bullets Periosteal patches Prognosis Juvenile form prognosis correlates with age login to view 2 more bullets location login to view 1 more bullet appearance login to view 2 more bullets Adult form worse prognosis usually symptomatic and leads to DJD if untreated