Table 4

Relative risk reduction and numbers-needed-to-treat analyses for non-contact anterior cruciate ligament injury

ReferenceNon-contact ACL injury in groupFemale athletes per groupNon-contact ACL incidence rates*RRR (95% CI)NNT to benefit (NNTB)†,
NNT to harm (NNTH)‡ (95% CI)
Hewett et al
 Control54630.1110093 NNTB
 Intervention03660(NA)(50 NNTB to 723)
Myklebust et al
 Control189420.0938.8135 NNTB
 Intervention (first year only)108550.03(−0.9, 62.9)(53 NNTB to ∞ to 255 NNTH)
Mandelbaum et al
 Control6738180.2481.970 NNTB
 Intervention (first and second year total)618850.04(60.9, 91.6)(52 NNTB to 106)
Olsen et al
 Control57780.0680.7193 NNTB
 Intervention18080.01(−15.3, 96.8)(89 NNTB to ∞ to 1079 NNTH)
Petersen et al
 Control51420.2110028 NNTB
 Intervention01340(NA)(16 NNTB to 205)
Pfeiffer et al
 Control38620.04−49.4582 NNTH
 Intervention35770.08(−233.4, 33.1)(188 NNTB to ∞ to 114 NNTH)
Gilchrist et al
 Control105830.1886.368 NNTB
 Intervention28520.06(51.5, 96.1)(39 NNTB to 265)
Steffen et al
 Control29470.03−32.41462 NNTH
 Intervention310730.05(−171.1, 35.4)(277 NNTB to ∞ to 201 NNTH)
Kiani et al
 Control57290.08100146 NNTB
 Intervention07770(NA)(78 NNTB to 1153)
LaBella et al
 Control67550.4865.9191 NNTB
 Intervention27370.10(−13.5, 89.7)(80 NNTB to ∞ to 470 NNTH)
 Control126100190.1473.4108 NNTB
 Intervention2780640.04(62.5, 81.1)(86 NNTB to 150)
  • *Relative incidence rate (per 1000 A*h).

  • †NNT to benefit (NNTB) represents a beneficial preventive effect of the intervention.

  • ‡NNT to harm (NNTH) indicates harmful effect of the intervention. Infinity (∞) means no beneficial or harmful effects.