Introduction Injuries are the major cause of morbidity and loss of active training days in military populations. Previous investigations have mainly focused on lower extremities. This study evaluated the incidence, diagnosis, and risk factors of upper extremity injuries requiring hospitalization in a large cohort of Finnish conscripts during a 5-year period.

Materials and Methods A total of 128,714 male military conscripts, who served 6–12 months in compulsory military service, were studied. Injury hospitalization data were obtained from the National Hospital Discharge Register. The main outcome variables were hospitalization due to any injuries to the upper extremity and hospitalization due to traumatic shoulder dislocation. Background variables for risk factor analysis included length of military service, age, body height and weight, body mass index, and physical fitness.

Results Overall person-based incidence rate for hospitalization due to upper extremity injury was 743 (95% confidence interval [CI]: 697–791) per 100,000 conscripts per year. Shoulder joint dislocation was the most common injury: incidence rate of 103 (95% CI: 86–122) per 100,000 conscripts per year. Trend during follow-up years 1998–2002 was decreasing concerning on any upper extremity injuries (odd ratios [OR] 0.90; 95% CI: 0.86–0.95, P < 0.001). Body mass index > 25 increased a risk for any injuries of the upper extremity (OR 1.29; CI 95%: 1.10–1.51) and, especially, for shoulder joint dislocation (OR 1.88; CI 95%: 1.26–2.80).

Conclusions Overweight young men were at greater risk for upper extremity injuries. The incidence rate of traumatic shoulder joint dislocation was considerably higher than reported previously. In conclusion, preventive measures such as reducing the body weight of overweight young men should play an important role in reducing the incidence of upper extremity injuries.