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Table 2 Results of RSA

From: Effect of symmetrical restoration for the migration of uncemented total hip arthroplasty: a randomized RSA study with 75 patients and 5-year follow-up

  Mean stem migration (Stdev) in relation to direct postoperative reference examination
Early migration Late migration
2 weeks 3 months pvalue£ 1 year 2 years 5 years pvalue$
Rotation (°)
X-axis
 All stems 0.15 (0.52) 0.15 (0.65) 0.13 0.09 (0.67) 0.17 (0.61) 0.27 (0.79) 0.01
 Modular stems 0.12 (0.52) 0.11 (0.65) 0.54 0.01 (0.67) 0.12 (0.61) 0.16 (0.79) 0.18
 Standard stems 0.21 (0.49) 0.24 (0.72) 0.27 (0.72) 0.28 (0.66) 0.51 (0.68)
Y-axis
 All stems 0.66 (1.27) 1.03 (1.51) < 0.001 1.05 (1.41) 1.23 (1.60) 1.47 (1.70) < 0.001
 Modular stems 0.61 (1.27) 1.07 (1.51) 0.35 1.11 (1.41) 1.32 (1.60) 1.56 (1.70) 0.93
 Standard stems 0.76 (1.49) 0.95 (1.67) 0.92 (1.61) 1.03 (1.97) 1.25 (2.02)
Z-axis
 All stems − 0.56 (0.57) − 0.69 (0.68) < 0.001 − 0.70 (0.71) − 0.75 (0.77) − 0.82 (0.77) < 0.001
 Modular stems − 0.55 (0.57) − 0.69 (0.68) 0.74 − 0.69 (0.71) − 0.76 (0.77) − 0.81 (0.77) 0.62
 Standard stems − 0.60 (0.70) − 0.69 (0.82) − 0.72 (0.83) − 0.74 (0.95) − 0.84 (0.89)
Translation (mm)
X-axis
 All stems 0.16 (0.25) 0.18 (0.26) < 0.001 0.18 (0.27) 0.20 (0.29) 0.23 (0.30) 0.001
 Modular stems 0.14 (0.25) 0.18 (0.26) 0.50 0.16 (0.27) 0.19 (0.29) 0.21 (0.30) 0.15
 Standard stems 0.21 (0.29) 0.19 (0.32) 0.22 (0.33) 0.21 (0.39) 0.28 (0.33)
Y-axis
 All stems − 0.76 (0.83) − 1.00 (1.10) < 0.001 − 1.00 (1.12) − 0.89 (1.21) − 0.92 (1.11) 0.09
 Modular stems − 0.70 (0.83) − 0.88 (1.10) 0.17 − 0.88 (1.12) − 0.84 (1.21) − 0.86 (1.11) 0.77
 Standard stems − 0.90 (0.89) − 1.25 (1.21) − 1.25 (1.22) − 1.01 (1.49) − 1.05 (1.07)
Z-axis
 All stems 0.01 (0.26) 0.03 (0.34) 0.22 0.06 (0.42) 0.02 (0.40) 0.01 (0.44) 0.66
 Modular stems 0.00 (0.26) − 0.02(0.34) 0.02 − 0.03 (0.42) − 0.04 (0.40) − 0.09 (0.44) 0.03
 Standard stems 0.03 (0.23) 0.14 (0.43) 0.25 (0.51) 0.14 (0.53) 0.23 (0.48)
  1. £p values for estimates of changes before 3 months representing the period when the stem settles in place
  2. $p values for estimates of changes from 3 months after surgery during which osseous integration and stabilization should have occurred