Morel-Lavallee Lesion: POCUS Review

This case describes an 18-year-old woman who presented to the pediatric emergency department with 2 days of worsening right knee pain and swelling. The patient's history was remarkable for a motor vehicle accident 12 days before presentation, as well as recent treatment for a gonococcal sexually transmitted infection 9 days before presentation. Her examination was notable for a large area of fluctuance of her right knee without overlying erythema or appreciable intraarticular effusion. Point-of-care-ultrasound (POCUS) revealed a large, subcutaneous fluid collection containing multiple, mobile septations. This was confirmed by radiology ultrasound, and the patient was seen by an orthopedic surgeon who recommended conservative management without aspiration of the fluid collection. To our knowledge, this is the first reported case of a Morel-Lavallee lesion being diagnosed by POCUS in a pediatric patient. This case demonstrates the utility of POCUS in facilitating the prompt recognition of shear injuries in children and guiding management in the emergency department.