Summary

The Morel-Lavallee lesion (MLL) of the knee region has been described in the Orthopaedic literature, and all of those were fit and healthy young participants sustaining sports-related trauma to the knee. We describe a case of an elderly woman, on aspirin and prophylactic clexane, who sustained a low-energy injury to the right knee and developed an MLL of the knee region. A delayed recognition, led to the persistence of the MLL as a diffuse haematoma, which subsequently became colonised with methicillin-resistant Staphylococcus aureus. We discuss the management of a case and highlight the importance of early identification and management of MLL of the knee region. Further evidence needs to be collected about MLL lesions in elderly, frail patients who are anticoagulated, and have increased risk of falls. This cohort of patients is more vulnerable to bleeding and infection than a fit, young adult population.