Elbow Osteochondritis Dissecans of the capitellum is a non-inflammatory degeneration of subchondral bone occurring in the context of repetitive trauma to the lateral compartment of the elbow.
Panner’s disease and Elbow OCD may represent two different stages of the same disorder, but they do have different characteristics:
- Age of onset, cause, and natural history: Although Panner’s disease affects children younger than 10 years, elbow OCD victimizes older athletes, usually between the ages of 11 and 15 years.
- Unlike Panner’s disease, elbow OCD is thought to be directly linked to repetitive trauma.
- OCD is not always a self-limited disease, and if left unaddressed, it results in profound destruction of the capitellum.
See Also: Panner’s Disease
The elbow’s osseous anatomy and the capitellum’s idiosyncratic blood supply may predispose young athletes to OCD. The elbow is a diarthrodial joint in which the distal humerus articulates with the proximal ulna and the radial head. Its unique bony configuration allows for 15 to 0 degrees° of extension to 150 degrees of flexion. Rotation of the radial head over the stationary ulna gives an arc of almost 180 degrees of forearm rotation.
The osseous and articular congruency of the humerus, ulna, and radial head accounts for the greater part of elbow stability, particularly at less than 20 degrees of extension or more than 120 degrees of elbow flexion. In young, skeletally immature athletes, the elbow possesses a greater degree of cartilaginous elasticity.
Hyperextension, facilitated by this increased range of motion, can generate increased radiocapitellar compressive loads and tension of the medial capsule and ulnar collateral ligament (UCL). Overhead throwing athletes during the throwing motion and gymnasts during weight-bearing handstands in elbow hyperextension further exaggerate these stresses. Repetitive stress on this system can precipitate OCD.
The tenuous end-artery vascular supply to the capitellum predisposes it to injury. In the young adult population, the capitellum is supplied by two end arteries coursing from posterior to anterior, which are branches of the radial recurrent and interosseous recurrent arteries . As a result of the longitudinal blood supply to the capitellar epiphyseal plate and minimal collateral circulation in the area, blood flow to the capitellum may be disrupted by repetitive microtrauma resulting in an avascular state and by a single traumatic event leading to posttraumatic subchondral bone bruises.
Elbow OCD Causes
Elbow OCD arises from repetitive, excessive compressive forces generated by large valgus stresses on the elbow during throwing or racket swinging or by constant axial compressive loads on the elbow, such as those endured by gymnasts.
Specific risk factors predispose to the condition:
- In the case of baseball players, throwing sliders and breaking pitches, throwing more than 600 pitches per season,
- Increased age of the athlete increase the risk of developing OCD.
- In female gymnasts, overtraining involving excessive handstand maneuvers has been linked to OCD.
- There also may be a genetic predisposition to OCD.
Elbow OCD Symptoms
Patients with elbow OCD initially complain of pain and stiffness in the elbow that is relieved by rest. The onset is usually insidious, and a history of specific trauma is often absent. If left unaddressed, the symptoms may progress to locking or catching due to intraarticular loose bodies or an inflamed plica.
Throwing athletes may present with painful posterolateral clicking or catching caused by a radiocapitellar plica. These symptoms can overlap with those from the elbow OCD lesion, and the plica itself may be responsible for chondral wear in the radiocapitellar compartment.
Because throwing athletes may have injured medial and lateral and posterior elbow structures, a full elbow examination is essential. UCL integrity is tested by performing a valgus stress test at 30 degrees, the milking maneuver, and the moving valgus stress test.
Posteromedial impingement is evaluated by performing a bounce test. A positive test result elicits pain posteromedially when the elbow undergoes forced hyperextension.
Loss of range of motion with a 15- to 20-degree flexion contracture is common. Loss of extension is more common than loss of flexion.
An effusion is often apparent and can be palpated by flexing the elbow and feeling the lateral portal area, triangulated by the radial head, olecranon, and lateral epicondyle.
The provocative maneuver for the radiocapitellar joint is the active radiocapitellar compression test. A positive test result elicits pain in the lateral compartment of the elbow when the patient pronates and supinates the forearm with the arm in extension.
In patients with an associated symptomatic radiocapitellar plica, snapping typically occurs at greater than 90 degrees of elbow flexion with the forearm in pronation.
Anteroposterior radiographs in full extension, anteroposterior radiographs in 45 degrees of flexion, and lateral views of the elbow should be obtained. Radiographic findings may be negative early in the disease process. As the condition progresses:
- flattening and sclerosis of the capitellum, typically on its anterolateral aspect, will become apparent.
- Irregular areas of lucency and intra-articular loose bodies also appear.
The capitellar lesions of OCD and medial-sided epicondylar fragmentation are best seen on an anteroposterior radiograph at 45 degrees of elbow flexion.
MRI should be used to assess suspected Elbow OCD. It can detect bone edema early in the disease process. An MR arthrogram can further delineate the extent of the injury. Contrast can show separation of a detached or partially detached piece from subchondral bone. This is important in determining whether to proceed with operative or nonoperative management.
Elbow Osteochondritis Dissecans Treatment
Treatment of Elbow OCD lesions is based primarily on the status and stability of the overlying cartilage. The size and location of the lesion and the patency of the capitellar growth plate also influence decision making.
Stage I (Stable):
- Normal radiograph
- T1 abnormal – T2 normal
- Intact articular cartilage
- Subchondral bone edema but structurally sound
- Hinged elbow brace for 3-6 wk
- Physical therapy
- Follow-up radiograph and/or MRI at 3-6 mo
Stage II (Unstable):
- Abnormal radiograph
- T1, T2 abnormal
- Contrast shows margin around lesion
- Partially detached fragment
- Cartilage fracture
- Subchondral bone collapse
- Lateral buttress involved with a poorer prognosis.
- Acute: consider fragment fixation, buthigher success treating as chronic condition
- <6-7 mm lateral buttress involved, radial head does not engage: fragment removal, microfracture drilling
- >6-7 mm lateral buttress involved, head engages: removal, osteochondral autograft, synthetic graft.
Stage III (Unstable):
- Loose bodies
- Completely detached Loose bodies
- Loose body removal
- Treat as stage 2 lesion.
Associated radial head OCD
Associated radial head OCD is treated as following:
- < 30% radial head involvement: treat as stage 2 lesion
- > 30% radial head involvement: no osteochondral grafting; microfracture drilling okay.
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