Intramuscular corticosteroid injection for hamstring injuries. A 13-year experience in the National Football League

The purpose of this study was to assess the safety of intramuscular corticosteroid injection in selected, severe hamstring injuries in professional football players. Clinicians have been reluctant to use corticosteroid injections in or around muscle-tendon units because of concern of incomplete healing or rupture. We retrospectively reviewed the computer database of one National Football League team for all hamstring injuries requiring treatment between January 1985 and January 1998. We found that 431 players had suffered such injury. We developed a clinical grading system to identify hamstring injury severity and to stratify players for treatment. Fifty-eight players (13%) sustained severe, discrete injuries with a palpable defect within the substance of the muscle and were treated with intramuscular injection of corticosteroid and anesthetic. There were no complications related to the injection of corticosteroid. Only nine players (16%) missed any games as a result of their injury. Final examination revealed no strength deficits, normal muscle bulk and tone, and the ability to generate normal power. We believe that the grading system we developed can assist in selection of injury type for injection. Although lack of a control group limits statements of efficacy of injection, our impression is that intramuscular corticosteroid injection hastens players' return to full play and lessens the game and practice time they miss.