What are osteochondral bodies in the elbow?

What Are Elbow Osteochondral Bodies?

Elbow osteochondral bodies are fragments of cartilage and underlying bone that have separated from the joint surface and become loose within the elbow joint, most commonly originating from the capitellum, and typically cause mechanical symptoms like locking, catching, or pain with movement. 1, 2

Pathophysiology and Origin

Osteochondral bodies develop through several mechanisms:

• Osteochondritis dissecans (OCD) is the most common cause, where disruption of cartilage and subjacent bone occurs, progressing through stages from radiolucent lesions to separation and eventually free fragments 3
• Repetitive mechanical stress in throwing athletes causes primary damage to articular cartilage with degenerative changes, followed by subchondral fracturing that leads to fragment separation 4
• Acute trauma can create osteochondral fractures that detach and become intra-articular bodies 3
• The capitellum is the most frequently affected site, though the trochlea can also be involved 3, 5

Clinical Presentation

These loose bodies cause distinct mechanical symptoms:

• Locking or catching sensations during elbow movement are the hallmark symptoms requiring surgical intervention 1, 2, 6
• Intermittent swelling accompanies the mechanical symptoms 6
• Pain with extension may occur, sometimes related to enlarged synovial plica rather than the loose body itself 1
• Limited range of motion develops as the disease progresses 6

Diagnostic Approach

Plain radiographs are mandatory as the first imaging step to identify loose bodies, heterotopic ossification, and osteochondral lesions 2, 6:

• Radiographs show intra-articular bodies and can stage OCD lesions through radiolucent, separation, and free (advanced) stages 1, 3
• Comparison with the contralateral asymptomatic elbow is recommended when findings are subtle 1, 6

Advanced imaging determines lesion stability and guides surgical planning 2:

• MR arthrography has 100% sensitivity for detecting intra-articular bodies and is the gold standard for surgical planning 1, 2
• MRI features indicating instability include cysts, osteochondral fractures, T2 hyperintense rim around the lesion, subchondral plate defects, and fluid-filled osteochondral defects 3
• CT arthrography evaluates stability with 93% sensitivity for loose bodies and 79% accuracy for detection, though small bodies may be obscured by contrast 1, 2

Treatment Algorithm

Surgery is indicated for loose intra-articular bodies causing mechanical symptoms or for unstable/displaced osteochondral fragments 2:

• Arthroscopic removal is the primary surgical approach for symptomatic loose bodies causing locking or catching 2, 7
• Stable lesions without mechanical symptoms should undergo conservative management with immobilization until healing, particularly in juvenile OCD with open growth plates 2, 5
• Lesions with intact overlying cartilage may benefit from retrograde drilling procedures, while those with damaged cartilage require reconstructive techniques using osteochondral grafts or cell-based procedures 5

Critical Pitfalls to Avoid

• Do not order MRI before plain radiographs, as MRI is less sensitive for detecting calcifications and ossified loose bodies 6
• Arthroscopic grading reveals that severity progresses from softened cartilage to fissuring, exposed bone, loose nondisplaced fragments, and finally displaced fragments creating intra-articular bodies 3
• Complete immobilization leads to muscle atrophy and joint stiffness, so gentle range-of-motion exercises should be incorporated once appropriate healing has occurred 6
• In young athletes with bilateral involvement, systematic evaluation of other joints may be warranted as multiple OCD lesions can occur simultaneously 7