Distal clavicle osteolysis is the painful osseous resorption of the distal clavicle.
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Epidemiology
Distal clavicle osteolysis most commonly affects young males. It is bilateral in ~20% 1.
Pathology
There are two distinct forms of distal clavicle osteolysis although these have identical histopathologic and imaging findings 1,2:
- post-traumatic: weeks to more commonly months after injury
- atraumatic: stress-induced overuse, seen in laborers and overhead athletes, especially in weight-lifters
Radiographic features
Plain radiograph
May be normal early in the disease course. Progressive disease can manifest with cortical irregularity, subchondral cysts and erosion/tapering of the distal clavicle 1,3.
MRI
Bone marrow edema of the distal clavicle more than the acromion with subchondral cystic change +/- subchondral fracture, and distal clavicle periostitis 1,2. Acromioclavicular joint effusion and capsular edema may be present 1.
Treatment and prognosis
Most patients respond to conservative treatment (exercise modification, NSAIDs, ice cooling). On follow-up MRI 2:
- acromioclavicular joint osteoarthritis is common (~70%)
- flattening of the distal clavicle
- acromioclavicular joint widening
Differential diagnosis
See article: distal clavicular erosion (differential).