What is Osteochondritis Dissecans (OCD) of the Capitellum?
OCD of the capitellum is a localized fragmentation and separation of subchondral bone - meaning the bone below the cartilage - in your elbow.
Overview of OCD of the Capitellum
Osteochondritis dissecans (OCD) is a painful condition in your elbow joint and occurs at the place where the end of one bone meets the end of another bone. It happens when the subchondral bone surrounding the capitellum of your elbow dies due to lack of blood flow. It results in cracking of the subchondral bone and the underlying cartilage, causing them to separate from the capitellum.
The capitellum is an enlarged knoblike structure on the outer side of the end of the upper arm bone, or humerus. It forms an articulation with another bone in the elbow joint. The capitellum is covered by smooth, slippery connective tissue called articular cartilage.
Subchondral bone is bone that is located just below the articular cartilage and acts as a shock-absorber. It has many blood vessels supplying it with oxygen and essential nutrients.
Types of OCD of the Capitellum
There are two types:
- Stable OCD: Where the elbow will still have a full range of motion
- Unstable OCD: Where the elbow suffers from loss of motion
Who is at Risk of OCD of the Capitellum?
The condition is most common in:
- Children and teens who are very active in sports
- Young athletes engaged in sports that require overhead-throwing such as baseball
- People who repetitively stress their elbow, such as gymnasts or weight-lifters
Causes
The exact cause is unknown. However, you may experience the condition due to:
- Extreme pressure on or overuse of the capitellum resulting in multiple episodes of minor, unrecognized injury
- Repetitive trauma to the capitellum leading to bone damage
- Compromised blood supply to the subchondral bone or capitellum
- Increased valgus load (angled, outward bend) across the elbow joint
- Genetic predisposition
Symptoms
After OCD of the capitellum sets in, the loose bone along with the cartilage may remain in place or can move into the joint area.
Some of the major symptoms of the condition include:
- Pain in the elbow, particularly on the outer aspect or lateral side
- Pain that decreases with rest but increases with activity
- Reduced range of motion in the elbow or difficulty in straightening the elbow fully
Diagnosis
The diagnosis will begin with a detailed physical examination of the affected elbow which involves comparing it to the non-affected elbow.
The condition is then confirmed by imaging such as the following:
- X-ray
- MRI scan