Morel-Lavallée Lesion of the knee after low-energy impact in a healthy non-athlete

BACKGROUND AND OBJECTIVE: Morel-Lavallée Lesion (MLL) of the knee is an uncommon cause of knee swelling usually due to high-energy impact or in patients on anticoagulation. MLL of the knee due to low-energy non-athletic associated trauma in patients without antithrombotic therapy is rare. Early diagnosis can be achieved using point-of-care ultrasound. CASE REPORT: A 60-year-old female who was previously well was referred to our center for a persistently swollen left knee 2 months after a fall while on a flight of stairs. A point-of-care ultrasound identified a possible MLL of the knee. This was subsequently confirmed on magnetic resonance imaging (MRI). The lesion resolved with ultrasound-guided therapeutic aspiration. CONCLUSION: MLL of the knee should be a differential diagnosis of traumatic knee swelling, even in low-energy trauma and in patients without bleeding diatheses. Ultrasound is a readily available and rapid modality that can aid both in the diagnosis and management of such lesions.