Table 2

Comparison of changes in primary and secondary outcomes at the main trial endpoint (24 months from baseline)

Arthroscopic partial meniscectomy95% CISkin incisions only95% CIComparison95% CIP value
Mean changeMean changeMean diff
Primary endpoint
 KOOS5 21.811.2 to 32.413.63.0 to 24.28.2−3.4 to 19.80.161
 KOOS5 response (ie, at least 30% increase)*, n (%)11 of 22 (50)7 of 20 (35)0.15†−0.15 to 0.450.327‡
KOOS subscales
  Pain23.912.9 to 34.914.02.7 to 25.29.9−2.1 to 21.90.110
  Symptoms16.86.6 to 27.010.2−0.0 to 20.56.6−4.3 to 17.40.240
  Function in daily living20.010.4 to 29.611.01.3 to 20.79.0−1.4 to 19.40.095
  Function in sport and recreation18.52.5 to 34.512.9−3.9 to 29.75.6−11.8 to 23.00.529
  Knee-related quality of life23.112.0 to to 22.711.5−0.4 to 23.40.062
  VAS score5.8−2.6 to to 21.0−6.6−15.7 to 2.60.164
  EQ-5D-3L index value0.160.08 to to 0.190.05−0.04 to 0.130.301
SF-36 (acute version)
  Physical component summary7.92.8 to to 10.92.1−3.3 to 7.50.452
  Mental component summary−1.2−5.3 to 2.91.3−2.9 to 5.5−2.5−6.8 to 1.80.256
  Score, median (IQR)65–654–610 to 20.122§
  Response (ie, 6 or 7)¶, n (%)14 of 21 (67)7 of 19 (37)0.30†0.00 to 0.590.059‡
Physical performance measures
  One-leg hop test (affected knee), cm**8.7−2.0 to 19.4−0.2−11.1 to 10.78.9−3.2 to 21.00.155
  One-leg hop test (non-affected knee), cm**0.7−9.7 to 11.1−5.2−15.7 to 5.45.9−5.4 to 17.30.312
  Knee bending test, max number of knee bends (affected knee), n**2.1−2.4 to 6.51.2−3.3 to 5.80.9−4.2 to 5.90.740
  Knee bending test, max number of knee bends (non-affected knee), n**−0.1−4.3 to 4.22.1−2.3 to 6.5−2.2−7.1 to 2.80.392
  Isometric knee extensor strength (affected knee), Nm/kg**0.980.70 to 1.270.810.53 to 1.090.17−0.08 to 0.420.191
  Isometric knee extensor strength (non-affected knee), Nm/kg**0.940.61 to 1.270.720.40 to 1.040.23−0.05 to 0.500.117
  • Data were analysed using repeated measures mixed linear models; no imputations for missing data at 3-month and 24-month follow-ups. Imputation of missing values at baseline was done for all variables by imputing the mean of the follow-up values. However, if one or both of the follow-up values were missing, no imputation of values at baseline was done.

  • *Two patients with missing data in the skin-incisions-only group were not included.

  • †Risk difference.

  • ‡The P value for the risk ratio is obtained from a χ2 test.

  • §The P value for the difference in medians is obtained from a Mann-Whitney U test.

  • ¶One and three patients with missing data at follow-up in surgery and skin-incisions-only groups, respectively, were not included.

  • **One patient in the arthroscopic partial meniscectomy group and two patients in the placebo group had no baseline value, and it was not possible to impute a follow-up value since one or both of the follow-up values were missing as well, hence these patients could not be included in the analyses.

  • GPE, Global Perceived Effect; KOOS5, Knee injury and Osteoarthritis Outcome Score subscale 5; SF-36, Short-Form 36 items; VAS, Visual Analogue Scale.