Imaging Studies
Plain radiography
Obtain anteroposterior (AP) and 10-15° cephalic tilt views. Radiographs often appear normal in the early clinical course. With time, loss of subchondral bone detail in the distal clavicle, microcystic changes in the subchondral area, and widening of the acromioclavicular (AC) joint may be seen. The acromion is spared from lytic changes.
It is important to distinguish distal clavicle osteolysis (DCO) from AC joint arthritis, and outcomes after operative injury can differ substantially between the two conditions. DCO can be diagnosed when pathologic changes such as sclerosis, reactive bone formation, and subchondral cysts are restricted to the distal clavicle. The distinction between DCO and AC joint arthritis is important because patients with traumatic AC joint arthritis and degenerative arthritis tend to do worse than patients with DCO do. [12]
The presence of panarticular disease should lead to the consideration of other diagnoses (eg, inflammatory disease).
Bone scanning
If plain radiography is nondiagnostic, technetium-labeled bone scanning may help confirm the diagnosis of distal clavicle osteolysis. Increased radiotracer uptake is seen in the distal clavicle.
Magnetic resonance imaging
Some authors have recommended the use of magnetic resonance imaging (MRI) to rule out additional shoulder pathology. [13] MRI will commonly demonstrate increased signal intensity on fat-suppressed T2-weighted and short-tau inversion recovery (STIR) images. Bone marrow edema at the distal clavicle also is a common finding and has been shown to correlate with the severity of symptoms. [12, 14]
Procedures
Because of a moderate incidence of concomitant shoulder pathology (eg, rotator cuff pathology, labral pathology, subacromial impingement, glenohumeral instability), a lidocaine injection into the AC joint may help achieve a more accurate diagnosis. [15]
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Anteroposterior radiograph of 26-year-old male weightlifter with symptomatic distal clavicle osteolysis that responded to conservative measures.
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Left distal clavicle excision for distal clavicle osteolysis performed with bone-cutting shaver placed in anterior portal, as viewed from direct posterior-superior portal.
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Preoperative anteroposterior radiograph of male weightlifter with symptomatic distal clavicle osteolysis.
