Spontaneous Avascular Necrosis of the Humeral Head Following COVID-19 Vaccination.

We report a case of a 40-year-old man who presented with left shoulder pain and marked functional impairment two days after receiving the second dose of the Pfizer COVID-19 vaccine. Advanced imaging demonstrated focal avascular necrosis (AVN) of his humeral head. Initial management included simple analgesics, activity modification, and an ultrasound-guided intra-articular hydrodilatation injection. The patient subsequently had an improved range of motion but persistent severe shoulder pain. He has now been offered surgical intervention. Despite having risk factors for developing AVN previously, the patient did not demonstrate any recent risk factors for developing the disease. COVID-19 vaccination is known to cause severe joint pain and stiffness rarely. However, avascular necrosis is not a known or documented side effect. His symptoms arose directly after the administration of the vaccine, with no other demonstrable cause. Therefore, we are reporting COVID-19 vaccination as a potential new risk factor for AVN of the humeral head.