Table 4

ACL injury risk by occupation in members of the US Armed Forces, 2006–2018




Enlisted specialty*
Special operation forcesMechanised/ArmourArtillery/GunneryAviationEngineersMaintenanceAdministration, intelligence and communicationLogisticsMaritime/Naval specialties
RR (95% CI)1.19 (1.10 to 1.29)1.05 (0.97 to 1.13)1.07 (1.01 to 1.12)0.93 (0.86 to 1.00)1.04 (0.98 to 1.11)0.93 (0.90 to 0.95)0.93 (0.90 to 0.95)1.00 (0.97 to 1.04)0.81 (0.75 to 0.88)
Risk difference (per 1000 person-years)1.00.30.4−0.40.2−0.4−0.40.0−1.0
AR (%)15.84.66.3−8.03.9−8.0−8.0−0.2−23.5
P value<0.0010.220.010.050.22<0.001<0.0010.88<0.001
NNH101339152827−25764635−2564−2571−78292−1002
Officer specialty†Aviation officersEngineering and maintenanceAdministrationOperations and intelligenceLogisticsServices
RR (95% CI)0.89 (0.83 to 0.94)1.05 (0.99 to 1.12)0.94 (0.87 to 1.021.07 (1.00 to 1.15)1.13 (1.05 to 1.22)0.92 (0.87 to 0.98)
Risk difference (per 1000 person-years)−0.50.2−0.30.30.6−0.3
AR (%)−12.95.0−6.56.511.8−8.2
P value<0.0010.120.130.06<0.0010.01
NNH−21274581−398434791808−3187
  • *Contrasted to enlisted infantry.

  • †Referenced to ground and naval gunfire officers.

  • AR, attributable risk; NNH, number needed to harm; RR, relative risk.