Disclosures: Erin Barnes: Nothing to disclose

Case Description: Patient presented with focal pain over the left acromioclavicular (AC) joint. He additionally described transient left-sided symptoms of numbness/tingling in his posterior arm, lateral forearm and in his first 3 fingers. Symptoms were associated with overuse; occurring after workouts which included jabbing, punching, and non-contact sparring. He found relief only with rest from his regular physical activity. Physical exam revealed mild tenderness over AC joint and Scarf test positive for AC joint tightness but not pain. X-ray showed subchondral cystic changes in the distal clavicle with cortical irregularity at the AC joint. Ultrasound indicated AC joint widening with capsule distention, clavicular cortical irregularity, and increased Doppler signal suggestive of AC joint arthropathy and early stages of clavicular osteolysis.

Setting: Outpatient University Musculoskeletal Clinic.

Patient: 39-year-old right-hand-dominant male with 3 months of insidious onset left shoulder pain and left arm paresthesias exacerbated by boxing.

Assessment/Results: Patient was recommended to ice the AC joint and continue home exercise program. Activity modifications were to avoid overhead activities, upper extremity weightlifting, and punching/boxing. He was seen in follow up at outpatient PCP office with improvement in AC joint pain.

Discussion: This case describes a novel sport-specific mechanical etiology of distal clavicular osteolysis in a boxing athlete. This diagnosis has historically been observed in weightlifting athlete populations but also in those with repetitive overhead activity. Clinical findings in the off-power/jab arm of this Orthodox style fighter indicate that his injury developed from a low impact mechanism in the setting of rapid and repetitive AC joint closure. This is in contrast to the heavy loads to which weightlifters are exposed and could suggest that pathogenesis can involve repetitive microtrauma rather than overt joint loading alone.

Conclusion: Consideration for AC osteolysis pathogenesis can include repetitive lower-force microtrauma rather than overt high-force joint loading as is seen most commonly.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/acromioclavicular-osteolysis-in-a-boxer-a-jab-to-the-conventional-presentation/