What is distal clavicle osteolysis?

What is Distal Clavicle Osteolysis

Distal clavicle osteolysis (DCO) is a pathologic condition characterized by progressive bone resorption and erosion of the distal clavicle at the acromioclavicular (AC) joint, typically resulting from repetitive microtrauma or overuse, most commonly seen in weightlifters and athletes. 1, 2

Pathophysiology

The underlying mechanism involves repetitive microtrauma to the distal clavicle that causes subchondral microfractures, triggering an abnormal repair process that leads to bone resorption rather than healing 2. This creates a cycle of ongoing bone destruction with cystic changes, osteoporosis, and loss of subchondral bone detail at the AC joint 3.

Clinical Presentation

Key Symptoms

• Insidious onset of aching pain localized to the AC joint region that progressively worsens with activity 2
• Pain specifically exacerbated by overhead activities, weightlifting (particularly bench press and dips), and cross-body movements 1, 4
• May present with functional limitations in daily activities and occupational tasks 1

Physical Examination Findings

• Point tenderness directly over the AC joint is the hallmark finding 2, 5
• Positive cross-body adduction test (pain with horizontal adduction across the chest) 2, 3
• Pain with overhead reaching and lifting maneuvers 1

Diagnostic Evaluation

Imaging Studies

• Plain radiographs show AC joint widening, osteoporosis, cystic changes, and loss of subchondral bone detail in the distal clavicle 1, 3
• Bone scintigraphy demonstrates increased uptake in the distal clavicle and is highly sensitive for early disease 3
• MRI can confirm DCO findings and help exclude other shoulder pathologies like rotator cuff disease 1

Important Differential Diagnoses

DCO must be distinguished from rotator cuff tendonitis, AC joint arthritis, AC joint separation, and other causes of shoulder pain, as misdiagnosis can lead to prolonged symptoms and delayed appropriate treatment 1, 4.

Etiology and Risk Factors

Two Main Categories

1. Atraumatic (most common): Associated with repetitive microtrauma from weightlifting, particularly in male athletes who perform bench press, dips, and overhead pressing movements 2, 3
2. Post-traumatic: Following acute AC joint injury or clavicle fracture 2, 4

The condition is strongly associated with weightlifting, with 45 of 46 patients in one series being weightlifters, earning it the nickname "weightlifter's shoulder" 3, 4.

Treatment Approach

Initial Conservative Management

Conservative treatment should be initiated immediately upon diagnosis and includes: 2, 4

• Complete avoidance of provocative activities (weightlifting, overhead movements, cross-body activities)
• Activity modification with cessation or significant reduction of weight training
• Ice massage to the AC joint
• NSAIDs for pain control and anti-inflammatory effect
• Range-of-motion exercises once acute pain subsides 1

Conservative management is most effective when initiated early, and can result in symptom improvement in patients willing to modify or cease their training activities 3.

Adjuvant Treatments for Refractory Cases

• Corticosteroid injections into the AC joint may provide temporary relief 1, 4
• Consider in patients who fail initial conservative measures but wish to avoid surgery

Surgical Intervention

Surgery is indicated when: 2, 5

• Conservative treatment fails after an adequate trial (typically 3-6 months)
• Patient has persistent point tenderness over the AC joint
• Abnormal radiographic and scintigraphic findings are present
• Patient is unwilling or unable to modify weightlifting or manual labor activities

The surgical procedure is distal clavicle resection (Mumford procedure), which involves removing approximately 1-2 cm of the distal clavicle 2, 3. This procedure has shown excellent results, with 19 of 19 followed patients in one series achieving symptom relief, and most able to return to sports activities and weight training 3.

Prognosis and Prevention

Early recognition and treatment are essential to prevent progression to more severe AC joint pathology or instability 4. Patients who undergo surgery generally have excellent outcomes and can return to sport-specific activities 3. However, those managed conservatively often must permanently modify or cease their weightlifting activities to maintain symptom relief 3.

Prevention strategies include: 4

• Proper weightlifting technique with emphasis on form over weight
• Gradual progression of training intensity
• Avoiding excessive volume of exercises that stress the AC joint (bench press, dips, overhead press)
• Early recognition of AC joint pain and immediate activity modification

Critical Clinical Pearls

The most common pitfall is misdiagnosis as rotator cuff tendonitis, which delays appropriate treatment and allows progression of bone resorption 1. Any athlete presenting with AC joint pain, particularly weightlifters, should be evaluated specifically for DCO with appropriate imaging. The combination of localized AC joint tenderness, positive cross-body adduction test, and characteristic radiographic findings makes the diagnosis straightforward once considered 2, 5.