A 28-year-old woman with no underlying health issues was injured in a motorcycle accident and taken to our hospital by ambulance when she was 26 years old. Though she was diagnosed with multiple trauma, upon arrival at the hospital neither cardiac murmurs nor cardiac abnormalities on transthoracic echocardiography were detected. She was managed conservatively, and discharged on hospital day 16. She experienced dyspnea upon mild effort, and an early diastolic murmur appeared. She was again referred to our hospital, and diagnosed with severe aortic regurgitation. We scheduled an aortic valve replacement using an bioprosthetic valve because she intended to give birth. We also considered simultaneous aortic root enlargement as her aortic annulus was small. We performed the surgery 2 years after the initial motorcycle accident. Perioperatively, we noticed that her non-coronary cusp was torn. We converted the procedure to an aortic valve repair using an autologous pericardial patch. Her aortic regurgitation disappeared after the operation, and she was discharged on postoperative day 14. We successfully preserved the aortic valve cusps and avoided the need for anticoagulant therapy.