Table 4

Spearman's rank-order correlations (rs) and rank-order partial correlations (rsp) between muscle function and PROs at 3 years

Knee functionKnee-specific activity
KOOS PainKOOS Sport/recKOOS QoLKOOS Q3TASARS
rs/rspp Valuers/rspp Valuers/rspp Valuers/rspp Valuers/rspp Valuers/rspp Value
Knee ext (W)0.0100.9410.1820.1890.0970.4850.1390.3150.2780.0420.0100.941
Knee ext (W)*0.0870.5400.1460.3020.1860.1860.1100.4400.3310.0170.0870.540
Knee ext LSI (%)0.2450.0740.1210.3830.3450.0110.1420.3040.2620.0560.2450.074
Knee ext LSI (%)*0.2460.0790.1440.3070.3390.0140.1530.2780.2720.0520.2460.079
Knee flex LSI (%)0.0380.7900.0310.8230.0550.695−0.0030.9860.0610.6640.0380.790
Knee flex LSI (%)*0.0330.8170.0330.8190.0620.6650.0030.9840.0660.6430.0330.817
Leg press LSI (%)0.1630.2380.0570.6840.0370.792−0.1460.2910.1110.4240.1630.238
Leg press LSI (%)*0.1450.3050.0410.7710.0640.652−0.1500.2890.1270.3700.1450.305
Vertical hop (cm)0.2310.0930.4290.0010.2550.0630.1610.2460.3090.0230.2310.093
Vertical hop (cm)*0.3330.0160.4580.0010.3430.0130.1350.3390.3300.0170.3330.016
Vertical hop LSI (%)0.3240.0170.2380.0830.3500.0090.1340.3340.2300.0940.3240.017
Vertical hop LSI (%)*0.3180.0210.2630.0600.3510.0110.1490.2930.2430.0820.3180.021
Side hop (n)0.1670.2270.3300.0150.1230.3760.1820.1870.4090.0020.1670.227
Side hop (n)*0.2010.1520.3200.0210.1430.3100.1640.2460.4090.0030.2010.152
Side hop LSI (%)0.2580.0590.2980.0280.3340.0140.2190.1120.3410.0120.2580.059
Side hop LSI (%)*0.2720.0510.3800.0050.3140.0230.2550.0680.3760.0060.2720.051
One leg hop LSI (%)−0.1520.272−0.0590.6710.0090.9480.1980.1520.0610.660−0.1520.272
One leg hop LSI (%)*−0.1460.300−0.0540.7020.0030.9840.1990.1580.0610.669−0.1460.300
TSP total score0.2810.0410.4260.0010.4000.0030.3430.0120.3680.0070.2810.041
TSP total score*0.3020.0310.4120.0030.4300.0020.3290.0180.3650.0080.3020.031
  • Bold numbers represent moderate correlations. Italic numbers represent close to moderate correlations. All assessment scores (except LSI) originate from the injured leg.

  • *Muscle function effect independent of gender and treatment.

  • ARS, Activity Rating Scale for disorders of the knee; KOOS, the Knee Injury and Osteoarthritis Outcome Score—function in sport and recreation (Sport/rec), knee-related quality of life (QoL), knee confidence (Q3); LSI, limb symmetry index; TAS, Tegner Activity scale; TSP, Test for Substitution Patterns; W, watt.