Delayed Post-Traumatic Lymphedema Following Misdiagnosed Navicular Fracture in a Diabetic Patient: A Case Report

Background:Isolated fractures of the tarsal navicular bone are rare and often overlooked due to their subtle presentation. While typically resulting from high-energy trauma, these fractures can be misdiagnosed as soft tissue injuries, leading to delayed treatment and potential long-term complications. One such complication, post-traumatic lymphatic obstruction, is extremely uncommon and poorly understood. This case highlights a unique presentation of secondary lymphedema developing years after an initially misdiagnosed navicular fracture in a patient with diabetes mellitus. Methods:A 35-year-old female with a history of diabetes mellitus presented with progressive swelling, warmth, and erythema in the left lower limb, five years after sustaining a foot injury initially diagnosed as an ankle sprain. Clinical examination and imaging were performed to evaluate the cause of persistent edema. Doppler ultrasound excluded deep vein thrombosis, while magnetic resonance imaging revealed navicular bone fragmentation, surrounding edema, and Achilles tendinopathy. Lymphoscintigraphy was used to assess lymphatic function and demonstrated obstructed lymphatic drainage in the affected limb. Based on these findings, a diagnosis of secondary lymphedema secondary to post-traumatic lymphatic dysfunction was established. Conclusion:This case underscores the importance of considering lymphatic disruption as a differential diagnosis in patients with unresolved lower extremity swelling following trauma, particularly when other common causes have been ruled out. Chronic inflammation, delayed diagnosis, and underlying comorbidities such as diabetes may contribute to lymphatic dysfunction. Early identification and multidisciplinary management—including physical therapy, compression therapy, and surgical consultation when necessary—are essential to prevent chronic lymphedema and functional impairment. Clinicians should maintain a high index of suspicion for secondary lymphedema in similar cases to improve long-term outcomes.