Disclosures: Hieu M. Pham, MD: No financial relationships or conflicts of interest

Case Diagnosis: Middle-aged female with congenital radioulnar synostosis (RUS)

Case Description: The patient is a middle-aged female with history of congenital RUS who presented with insidiously worsening dorsal left wrist pain, aggravated with motions that involved extension or supination of the wrist. Physical exam was remarkable for fairly long metacarpals and less dexterous fingers. She exhibited tenderness over the dorsal radiocarpal joints and lacked supination in her bilateral forearms. X-rays revealed congenital subluxation of both radial heads posteriorly with solid bony fusion between the proximal radius and ulna; findings suggestive of RUS. Musculoskeletal ultrasound revealed bony bridging between the radius and ulna in the proximal posterior/lateral forearm views, with an absence of the typical radial head profile. On dynamic assessment of the elbow with supination-pronation, no radial motion could be visualized. In addition, a non-compressible cystic structure consistent with a ganglion or synovial cyst was present dorsal to the lunate. Power Doppler showed no evidence of synovitis or hyperemia.

Setting: Musculoskeletal Outpatient ClinicAssessment/

Results: An attempt at ultrasound-guided aspiration of the cyst was unsuccessful due to the semi-solid nature of the cyst contents, but injection was performed with a mixture of 1.5 mL of 1% lidocaine and 0.5 mL of Kenalog (40 mg/mL) into the cyst. On her follow up visit, the patient reported complete relief of her symptoms.

Discussion: This case report gives an example of the emerging role of musculoskeletal ultrasound in the diagnosis and evaluation of skeletal pathology of the elbow. The use of dynamic movements during ultrasound evaluation can help aid diagnosis.

Conclusion: To our knowledge, conservative management of this disorder has not been systematically studied and is rarely described. Surgical treatment is typically recommended in childhood. Surgical interventions include rotational osteotomy. The current case represents an interesting case of RUS evaluated with diagnostic musculoskeletal ultrasound and treated with ultrasound guided intervention.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/ultrasound-evaluation-and-guided-injection-for-wrist-pain-secondary-to-radioulnar-synostosis/