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Table 3 Postural way in the near-tandem quiet standing test and gait parameters in the 6-min walk test [median (interquartile range)]

From: Pain, balance, and mobility in people 1 year after total knee arthroplasty: a non-randomized cross-sectional pilot study contrasting posterior-stabilized and medial-pivot designs

  PS-TKA
(n = 20)
MP-TKA
(n = 18)
Controls
(n = 19)
K-W PS-TKA vs
MP-TKA
PS-TKA vs Controls MP-TKA vs Controls
p value p value ES p value ES p value ES
The near tandem quiet standing test
Lumbar
  AP sway range (°) 1.36 (1.03 to 2.16) 1.69 (1.16 to 2.33) 1.26 (0.81 to 1.38) 0.041* 0.287  − 0.13 0.117  − 0.32 0.011  − 0.49
  ML sway range (°) 1.74 (1.15 to 2.24) 1.53 (1.03 to 2.45) 2.15 (1.15 to 2.67) 0.953 0.717 0.06 0.443  − 0.22 0.822  − 0.15
  RMS angular velocity (°/s) 1.69 (1.29 to 1.94) 1.69 (1.43 to 2.36) 1.33 (1.10 to 2.38) 0.784 0.601  − 0.08 0.255  − 0.01 0.301  − 0.05
Head
  AP sway range (°) 2.65 (2.05 to 3.96) 3.55 (2.41 to 4.52) 2.26 (1.69 to 2.96) 0.023* 0.234  − 0.28 0.100  − 0.28 0.006  − 0.35
  ML sway range (°) 3.59 (2.34 to 4.73) 4.20 (2.10 to 7.51) 3.70 (2.32 to 5.06) 0.219 0.355  − 0.15 0.717  − 0.01 0.796  − 0.01
  RMS angular velocity (°/s) 2.79 (1.85 to 3.28) 3.27 (2.25 to 3.93) 2.41 (1.98 to 4.41) 0.314 0.212  − 0.20 0.959  − 0.03 0.301  − 0.08
6-min walk test
  Cadence (steps/min) 109.97
(102.70 to 113.96)
110.13
(102.90 to 114.91)
113.87
(113.00 to 119.64)
0.004* 0.585  − 0.02 0.006  − 0.31 0.033  − 0.40
  Stride time variability (ms) 23.86 (19.19 to 31.64) 23.09 (19.00 to 30.89) 16.46 (12.58 to 19.28)  > 0.001* 0.984  − 0.03 0.001  − 0.50 0.001  − 0.52
  Step time asymmetry (%) 3.09 (1.34 to 7.88) 3.80 (1.85 to 5.74) 1.34 (0.80 to 2.76) 0.005* 0.516  − 0.12 0.046  − 0.04 0.007  − 0.40
Lumbar displacement (cm)
  RMS AP 0.94 (0.80 to 1.10) 0.88 (0.66 to 0.98) 1.00 (0.92 to 1.13) 0.138 0.235  − 0.19 0.737  − 0.08 0.098  − 0.27
  RMS ML 1.41 (1.28 to 1.59) 1.49 (1.27 to 2.05) 1.08 (0.74 to 1.36) 0.002* 0.351  − 0.01 0.035  − 0.40 0.002  − 0.49
  RMS VT 0.99 (0.91 to 1.18) 0.91 (0.83 to 1.21) 1.30 (1.07 to 1.62) 0.001* 0.482  − 0.11 0.009  − 0.40 0.001  − 0.50
Head displacement (cm)
  RMS AP 0.32 (0.27 to 0.40) 0.35 (0.27 to 0.47) 0.31 (0.22 to 0.37) 0.640 0.658  − 0.07 0.698  − 0.09 0.191  − 0.16
  RMS ML 2.64 (1.98 to 3.06) 2.35 (1.80 to 2.87) 1.45 (1.05 to 1.83)  < 0.001* 0.875  − 0.08  < 0.001  − 0.54  < 0.001  − 0.55
  RMS VT 0.87 (0.751 to 1.02) 0.89 (0.73 to 1.12) 1.15 (1.05 to 1.53)  < 0.001* 0.699  − 0.06 0.001  − 0.45 0.003  − 0.41
Lumbar harmonic ratio
  AP 1.83 (1.63 to 2.05) 1.67 (1.53 to 1.79) 1.95 (1.75 to 2.19) 0.010* 0.273  − 0.34 0.542  − 0.33 0.007  − 0.38
  ML 0.76 (0.66 to 0.88) 0.79 (0.73 to 0.96) 0.83 (0.77 to 1.00) 0.020* 0.942  − 0.04 0.109  − 0.31 0.017  − 0.42
  VT 1.88 (1.62 to 1.97) 1.67 (1.44 to 1.85) 1.90 (1.80 to 2.11) 0.011* 0.633  − 0.15 0.241  − 0.21 0.008  − 0.44
Head harmonic ratio
  AP 1.41 (1.27 to 1.48) 1.41 (1.28 to 1.47) 1.56 (1.47 to 1.79)  < 0.001* 0.903  − 0.07 0.001  − 0.37  < 0.001  − 0.53
  ML 0.87 (0.80 to 1.02) 0.82 (0.80 to 0.92) 0.89 (0.76 to 0.95) 0.015* 0.965  − 0.14 0.034  − 0.48 0.009  − 0.44
  VT 1.99 (1.77 to 2.15) 1.91 (1.72 to 2.15) 2.14 (2.01 to 2.44) 0.003* 0.699  − 0.06 0.019  − 0.32 0.005  − 0.40
  1. AP anteroposterior, ES effect size, K-W Kruskal–Wallis test, ML mediolateral, MP-TKA medial pivot total knee arthroplasty, PS-TKA posterior-stabilized total knee arthroplasty, RMS root mean square, VT vertical
  2. *Denotes significant difference at p < 0.05 using Kruskal–Wallis test
  3. Denotes significant difference from control at p < 0.05/3 using Mann–Whitney U test with Bonferroni adjustment