The hypothenar hammer syndrome is a rather rare vascular injury. It is seen in posttraumatic digital ischemia caused by occlusion of the distal ulnar artery at the level of the hamate bone. It characteristically occurs in the dominant hand of middle-aged men whose occupational or recreational activities require the use of the hand as a hammer. We report a case of this syndrome in a young female elite badminton player who subsequently underwent microvascular reconstruction and returned to competitive sports. CASE REPORTA 16-year-old female badminton player came to our clinic with a 1-week history of pain and pallor in her right index, long, and ring fingers. The symptoms had begun just after she competed in the International Badminton Junior Championships in Amsterdam in 1985 where she had ranked third overall. The patient had been training seriously in this sport for about 3 years before this episode. Pertinent physical examination centered on the patient's right hand. Coldness of the entire hand and tenderness over the hypothenar eminence were found. The Allen test result was positive, and complete occlusion of the ulnar artery at the level of the hamate was suggested by Doppler flowscope examination. To avoid the risk of aggravating symptoms by vasospasm, an angiogram was not done. Routine laboratory examinations showed results within normal limits. Thermography confirmed the physical examination findings (Fig. 1).The patient was admitted to the hospital with a diagnosis of hypothenar hammer syndrome, and anticoagulant therapy was used for 3 days. Her symptoms did not improve, but she was discharged temporarily to participate in the games of the National Junior Championships. She won the championship and subsequently was readmitted for surgery. Microvascular reconstruction was performed at 2 weeks from the onset of symptoms. Intraoperatively, a thrombosed aneurysm of the superficial palmar arch was found with aneurysmal dilatation and thrombus formation extending proximally into the ulnar artery for about 4 cm ( Fig. 2A). The aneurysm was resected, and an interpositional vein graft was placed between the distal ulnar artery and the third common digital artery (Fig. 2B). Pathologic sections showed an organized thrombus occupying the lumen with thickening of the arterial wall and with rupture of the muscular layer.Immediately postoperatively, the temperature of the involved hand improved (Fig. 1). The patient resumed her training program 1 month after surgery, attended the next national games at 2 months postoperatively, and ranked second overall. She was a member of the Japanese national team and participated in the Olympic Games in Barcelona in 1992. DISCUSSIONThe hypothenar hammer syndrome was first described by von Rosen in 1934 and is recognized by posttraumatic digital ischemia caused by occlusion of the distal ulnar artery at the level of the hamate bone. Most of the reported cases are middle-aged men who engage in typical occupational or recreational activities that require the use of the hand as a hammer...