Undiagnosed von Willebrand Disease Presenting as Delayed Hematoma after Total Hip Arthroplasty: A Case Report.

INTRODUCTION: Total hip arthroplasty is an effective procedure for end-stage hip disease, yet post-operative hematoma may signal an underlying bleeding disorder, particularly when the presentation is delayed. von Willebrand disease, the most common inherited coagulopathy, often remains undiagnosed in older adults because bleeding histories can be subtle or atypical. We are not aware of a previously reported case in which a delayed post-operative hematoma led to a new diagnosis of von Willebrand disease following primary total hip arthroplasty. CASE REPORT: A 61-year-old male with diabetes mellitus, chronic kidney disease stage 1, morbid obesity, chronic obstructive pulmonary disease, and peripheral arterial disease underwent primary right total hip arthroplasty through a posterolateral approach. Estimated intraoperative blood loss was 900 mL, at the upper end of the range typically observed for this procedure; no transfusion was required, and nothing in the operative course raised suspicion for a bleeding disorder. He received post-operative thromboprophylaxis with enoxaparin 30 mg every 12 h for 4 days. Nearly 2 weeks later, he developed progressive posterior thigh and gluteal swelling. Imaging confirmed a large soft-tissue hematoma with intact prosthetic components. Surgical evacuation yielded 400 mL of organized hematoma. Hematologic evaluation revealed elevated von Willebrand factor antigen, elevated factor VIII activity, and severely reduced von Willebrand factor activity, consistent with previously undiagnosed von Willebrand disease. CONCLUSION: Delayed or atypical hematoma after total hip arthroplasty should prompt evaluation for occult bleeding disorders, including von Willebrand disease. Early recognition and individualized hemostatic planning are essential to reduce morbidity in future procedures, and this report highlights the value of a structured perioperative bleeding assessment in medically complex arthroplasty candidates.