Clin J Sport Med 2005;15:279-280) S tress fractures associated with tennis are uncommon, especially for the upper limb. 1,2 Stress fracture of the humerus, 3 forearm, 4-6 and carpal bones 7 have been reported in regular tennis players. To our knowledge, only two cases with stress fracture of the second metacarpal have been reported in the literature. 8,9 Our patient is a soft tennis player, a sport whose technique and stroke biomechanics do not resemble regular tennis. We discuss the cause of this soft tennis injury and how to confirm early diagnosis and rapid return of the patient to play this sport. CASE REPORTA 13-year-old, right-handed, female junior high school student had acute onset of pain on the dorsal aspect of the second metacarpal. She was a soft tennis player and had been practicing this sport 3 hours per day for the past 12 months with no injury to the right hand. She increased the amount and intensity of her tennis training in preparation for a major tournament. The coach recommended she use the Western forehand grip rather than the Eastern forehand grip because soft tennis requires stronger hitting rather than the top-spin hitting of regular tennis. She noted increasing hand pain each time she hit the ball and could not play tennis by the third day after onset of pain. Initially, she visited a private hospital, but no apparently abnormal findings were detected by radiography (Fig. 1). She stopped playing soft tennis, but the hand pain did not improve. The patient visited our hospital for further examination 3 weeks after the onset of pain. Physical examination revealed point tenderness, swelling, and a hard mass over the second metacarpal of the right hand. Radiographic evaluation of the right hand revealed a visible fracture line and periosteal reaction (callus formation) at the base of the second metacarpal. Magnetic resonance imaging (MRI) showed high abnormal signal and confirmed a stress fracture of the second metacarpal. Her sports activity using the right hand was restricted until resolution of the pain in her hand. Five weeks after her initial visit, radiographs confirmed a solid bony union at the fracture site (Fig. 2), and the pain was relieved even with a full grip of the tennis racket. At 6 weeks, the patient was released for full, unrestricted sports activity. The coach advised her to change the racquet grip and her tennis stroke. Three months after the injury, she continues to play soft tennis at a high level of activity without any recurrence of hand pain. DISCUSSIONStress fractures in athletes occur infrequently in the nonweight-bearing upper extremity. 1,2 Tennis is not a sport in which stress fractures commonly occur, but tennis-associated stress fractures of the upper extremity, such as the humerus, 3 the distal radius, 4 the distal ulna, 5 the hamate hook, 7 and the second metacarpal 8,9 have been reported.The equipment, technique, and stroke movements of soft tennis are different from those of regular tennis. Soft tennis was developed in Japan and is now a very popular spo...

Little is known about the fate of graft cells following vascularized bone allografting. This study was conducted to define the process of graft-cell repopulation with recipient cells. Sixty-five vascularized tibial bone and 50 limb allotransplantations were performed in rat sex-mismatched pairs. FK 506 was used for immunosuppression. The ratio of donor and recipient cells in the graft was evaluated by semiquantitative polymerase chain reaction, using the Y-chromosome primers. Allografted bones had no rejection episodes. In the vascularized bone allograft model, donor-derived cells were gradually replaced by cells of recipient origin, such that by 24 weeks, they comprised only 10% of total cells. In the limb allograft model, male recipient cells were detected in female grafts not at 1 week but at 48 weeks posttransplantation. The ratio of recipient cells was more than 10% in the femur and tibia. Recipient-derived cells gradually migrated into the grafted bone cells with the passage of time.

Few papers have assessed the long-term functional recovery of animal limb allografts. In this study, the functional recovery of rat limb allografts was serially and quantitatively investigated for a period of 1 year. The donor's hind limb was orthotopically transplanted into the recipient. Fifteen recipients with allografts were treated with FK506. Functional recovery of the grafted limb was assessed serially by cutaneous reaction test, walking track analysis, and electrophysiologic evaluation. Sensibility improved to a similar extent in both isografts and allografts, and the recovery rate at 1 year was 68 percent, compared to the normal side. Sciatic function index significantly improved to - 70 points after 1 year. The amplitude recorded from the gastrocnemius muscle significantly improved, and the ratio compared to the normal side was 43 percent. Limb isografts and allografts treated with FK506 showed no significant differences in functional recovery. The data can be used as a reference standard for future investigations.

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