Stress fractures of the metacarpal bones in adolescent tennis players: a case series.

BACKGROUND: There are 12 reported cases of metacarpal stress fractures in athletes, with only 4 of them involving the second metacarpal.

PURPOSE: The authors describe stress fracture of the second metacarpal bone in teenaged tennis players and the relationship with sport intensity and type of grip used. They also demonstrate that magnetic resonance imaging is the diagnostic study of choice to differentiate this entity from the most common cause of pain in this region of the hand in tennis players-the carpal boss.

STUDY DESIGN: Case series; Level of evidence, 4.

METHODS: Seven adolescent tennis players (mean age, 16.5 years; 6 female, 1 male) with dorsal hand pain produced by playing tennis were examined by radiographs and initial magnetic resonance imaging. In 2 cases, bone scintigraphy was performed. In the first 2 cases, the presumptive diagnosis was a carpal boss, but with this experience, the diagnostic evaluation of the last 5 cases was oriented toward a stress reaction at this level. Radiologic follow-up was performed. The authors also evaluated the grip type used by each tennis player.

RESULTS: Clinical evaluation and imaging studies resulted in a diagnosis of stress injury of the second metatarsal in 6 of 7 cases, with the seventh case involving the third metacarpal. Initial imaging was positive in 3 cases, revealing an increased signal in the marrow without hairline crack and cortical thickening of the shaft or simply an increased signal in the marrow. In all cases, there was a history of recent increase in the sport training load. Six of the 7 tennis players were using a semi-Western or Western grip.

CONCLUSION: Stress fractures of the second metacarpal are characteristic of adolescent tennis players and are associated with an increased intensity of tennis play and may be associated with use of the semi-Western or Western grip. Magnetic resonance imaging is the most useful tool for obtaining a definitive diagnosis.