Malleolar Stress Fracture as the First Manifestation of Undiagnosed Crohn's Disease: A Case Report.

Introduction: Stress fractures (SFs) typically result from repetitive high-impact activities in athletes or military personnel. Their occurrence in young, non-athletic individuals without significant mechanical overload is uncommon and warrants investigation for underlying systemic conditions. Although Crohn's disease (CD) is associated with increased fracture risk due to chronic inflammation, malabsorption, and nutritional deficiencies, SFs as the initial manifestation of clinically silent CD are rarely documented. To the best of our knowledge, this represents the first reported case of a medial malleolar SF preceding the diagnosis of occult CD. This case is important because it illustrates a SF as a potential sentinel event for hidden inflammatory bowel disease (IBD), prompting orthopedic surgeons to broaden their differential diagnosis in atypical presentations. Case Report: A 28-year-old Caucasian man presented with a 3-week history of progressive medial left ankle pain without trauma or high-impact sports participation. His only relevant activity was repetitive low-intensity bouncing while caring for his infant child. Clinical examination showed localized supramalleolar tenderness, swelling, and an antalgic gait. Magnetic resonance imaging confirmed a medial malleolar SF. In the absence of adequate mechanical overload, further evaluation revealed systemic inflammation, hypoalbuminemia, and micronutrient deficiencies, with normal standard bone metabolism parameters. Despite no gastrointestinal symptoms, additional investigations confirmed active IBD, with histology diagnostic of CD. Conservative orthopedic management, nutritional support, and targeted anti-inflammatory therapy resulted in complete resolution of musculoskeletal symptoms. Conclusion: This case highlights that an SF can be the inaugural clinical sign of clinically silent CD. It contributes to the orthopedic literature by reinforcing the need to consider inflammatory and metabolic causes in young, non-athletic patients with SFs lacking a clear mechanical etiology. The implications extend beyond orthopedics, advocating a multidisciplinary approach to unexplained skeletal fragility. Early recognition of underlying systemic disease enables prompt intervention, optimizes bone health, and prevents recurrent or severe musculoskeletal issues. This report advances knowledge of CD as a systemic condition capable of compromising bone integrity independently of overt gastrointestinal symptoms.