Table 6 Stepwise regression analysis estimating multivariate association between preoperative physical outcome measures and physical activity level (independent variables) and physical activity level one year after surgery (dependent variable) (n = 108)

Gait speed, normal

0.430 (0.57)

0.449

0.502 (0.53)

0.348

Gait speed, fast

0.203 (0.39)

0.604

−0.159 (0.38)

0.677

Quadriceps strength, right

0.021 (0.02)

0.325

0.020 (0.02)

0.330

Quadriceps strength, left

−0.011 (0.01)

0.550

−0.010 (0.01)

0.547

ODI item four

−0.123 (0.12)

0.309

−0.062 (0.11)

0.586

Self-rated walking distance

0.079 (0.13)

0.548

0.084 (0.12)

0.499

Physical activity level

0.281 (0.07)

< 0.001

R Square = 0.174

0.003

R Square = 0.275

< 0.001