Osteochondritis dissecans (OCD) of the elbow is a rare diagnosis found mainly in the athletic adolescent population.

Causes / typical injury mechanism:

• OCD of the elbow can occur in all sports, but it is most common in baseball and gymnastics.
• Baseball – Occurs in the dominant arm due to the repetitive valgus load across the elbow during throwing.
• Gymnastics – Continuous impact can lead to trauma across the elbow. The few cases in which bilateral disease was identified were found in gymnasts.
• The capitellum is the most common aspect of the elbow to be involved, with a negligible amount of cases reported in the trochlea, radial head, or olecranon.
• OCD is also commonly found in the knee and ankle.

Classic history and presentation: Due to its involvement of the capitellum, elbow OCD typically will present with lateral-based elbow pain. Initially, the pain will occur with sport-specific maneuvers; however, it can progress to occur with activities of daily living, or constant pain in more severe cases. Most patients will not recall a major injury or incident but will report an insidious onset more consistent with repetitive use.

Prevalence: Overall, prevalence has been cited as ranging from 1%-3%.

• Age – OCD of the elbow typically occurs in patients aged 6-20 years, and the most common age group is patients aged 12-19 years (about 12 times more likely compared to patients aged 6-11 years).
• Sex / gender – OCD of the elbow is most commonly found in non-Hispanic White males.

Risk factors:

• Repetitive valgus load across elbow.
• Continuous weight-bearing impact across the elbow.

Pathophysiology: The direct cause is unknown. Theories include:

• "Mismatch" between the softer lateral capitellum and firmer radial head, leading to microtrauma to the capitellum from repetitive loading or overuse. Medial laxity can develop in overhand throwers, allowing for increased force across the radiocapitellar joint in valgus movements seen in throwing and with axial loading in gymnastics.
• Immature capitellum supplied by end arteries without much anastomosis with the metpahysis results in ischemia and leads to breakdown of subchondral bone.
• As the process progresses and worsens, the articular cartilage can fissure, flap, or even detach completely, resulting in intra-articular loose bodies.