Table 2

Multivariable results of the association between the clinical and MRI findings at initial injury and event of 2 months (31 (9%) reinjuries) and 12 months reinjuries (52 (17%) reinjuries)

VariableARR (95% CI)P valueTrend of prognosis of reinjury
2 months hamstring reinjury
 Clinical findings
  Straight leg raise angle on injured leg0.972 (0.945 to 1.000)0.054↓
  Presence of discomfort during active knee extension test3.380 (1.185 to 9.641)0.023↑
 MRI findings
  MTJ involvement2.522 (0.804 to 7.909)0.113↑
  Extent of haematoma transverse1.200 (0.715 to 2.012)0.490↑
  Extent of haematoma craniocaudal1.004 (0.909 to 1.107)0.940↑
12 months hamstring reinjury
 Clinical findings
  Previous hamstring Injury1.820 (0.624 to 5.307)0.273↑
  Previous ipsilateral hamstring injury1.359 (0.548 to 3.370)0.508↑
  Time to RTP0.985 (0.970 to 0.999)0.043↓
  Injury mechanism: sprinting vs non sprinting0.768 (0.380 to 1.550)0.461↓
  Presence of discomfort during active knee extension test2.517 (1.096 to 5.783)0.030↑
  Straight leg raise angle on injured leg0.975 (0.955 to 0.996)0.021↓
  Active knee extension test on Injured leg0.096 (0.981 to 1.011)0.607↓
  Active knee extension test on uninjured leg0.999 (0.981 to 1.017)0.938↓
  Isometric strength test at 90o on injured leg1.002 (0.996 to 1.008)0.527↑
  Isometric strength test at 90o on injured leg uninjured leg1.002 (0.995 to 1.009)0.505↑
 MRI findings
  Extent of oedema anteroposterior0.740 (0.570 to 0.961)0.024↓
  Extent of haematoma transverse1.445 (0.897 to 2.328)0.131↑
  MTJ involvement3.099 (1.387 to 6.931)0.006↑
  Presence of waviness0.712 (0.393 to 1.288)0.261↓

  • ↑=trending towards a positive association/increased with reinjury risk (ARR higher than 1); ↓=trending towards a negative association/decreased with reinjury risk (ARR less than 1).

  • ARR, adjusted risk ratio; MTJ, myotendinous junction; RTP, return to play.