A 32-year-old woman presented to our clinic with left elbow swelling and pain of 6 days’ duration. She’d had a posterior interosseous nerve (PIN) injection (hydrodissection) at another facility 12 days earlier for refractory intersection syndrome.
During nerve hydrodissection, fluid is injected into the area surrounding the nerve in an effort to displace the muscles, tendons, and fascia and thus reduce friction on the nerve. This treatment, often completed with ultrasound guidance, is utilized by patients who want to obtain pain relief without undergoing surgery for nerve entrapment syndromes.
In this case, a combination of 1 mL (40 mg) of methylprednisolone acetate, 1 mL of lidocaine 2%, and 3 mL of normal saline was injected into the supinator muscle belly (proximal dorsal aspect of the forearm) under ultrasound guidance. Six days later, the patient began to experience elbow pain, redness, and swelling. The symptoms progressed within several hours and became so notable that she sought care at an urgent care facility the next morning. At this facility, she was told she had an infection and was prescribed oral levofloxacin 500 mg/d.
The patient presented to our clinic after 4 days of oral levofloxacin with no improvement of symptoms. She denied chills or fever and described her pain as moderate and radiating to her fingers. There was no history of trauma. The patient reported riding her bike more frequently, which had caused the original forearm pain that warranted the PIN injection. There were no other recent changes to activity. Her medical, social, and surgical histories were otherwise unremarkable.
Her vital signs were normal. Physical exam revealed an erythematous and warm left elbow (FIGURE 1). Her left elbow range of motion (extension and flexion) was mildly decreased due to the pain and swelling.