The PCS scores improved at 4 weeks and 3 months but not at 1-year follow-up ( between-group difference , -2.7 [ 95 % CI , -4.6 to -0.85 ] at 4-week follow-up ; -2.2 [ 95 % CI , -3.9 to -0.49 ] at 3-month follow-up ; and -0.92 [ 95 % CI , -2.7 to 0.61 ] at 1-year follow-up ) .