Table 2

Bone strength and structure in healthy controls and patients with rheumatoid arthritis

 Stiffness, kN/mm45.3±14.6*36.4±13.9*†41.5±12.5†
 Failure load, N2184±667*1771±619*†1986±579†
Bone structure (HR-pQCT)
 Volumetric bone mineral density
  Dtotal, mg HA/cm³289±56*256±58*†286±61†
  Dtrab, mg HA/cm³164±37*‡130±47*†150±42†‡
  Dmeta, mg HA/cm³223±37*‡196±43*†207±41†‡
  Dinn, mg HA/cm³124±39*98±44*110±44
  Dcomp, mg HA/cm³786±66*‡750±104*†814±69†‡
  Meta/Inn, %1.96±0.65*2.28±1.02*2.06±0.66
 Bone microstructure
  BV/TV, %0.14±0.03*‡0.12±0.04*†0.12±0.03†‡
  Tb.N, 1/mm2.04±0.30*‡1.81±0.42*†1.93±0.37†‡
  TbTh, mm0.07±0.01*0.06±0.01*0.06±0.01
  Tb.Sp, mm0.44±0.11*‡0.54±0.23*†0.49±0.21†‡
  Tb.1/N.SD, mm0.19±0.07*‡0.29±0.24*0.23±0.15b
  Ct.Th, mm0.67±0.18*0.59±0.21*†0.69±0.19†
  • Bonferroni-Holm adjustment: critical P values indicating significant results for all investigated parameters were as follows: P1=0.0167, P2=0.025, P3=0.05.

  • *Significance between HC vs RA+.

  • †Significance between RA+ vs RA−.

  • ‡Significance between HC vs RA−.

  • BV/TV, trabecular bone volume per tissue volume; Ct.Th, cortical thickness; Dcomp, compact (cortical) volumetric bone mineral density (vBMD); Dinn, inner trabecular vBMD; Dmeta, meta-trabecular vBMD; Dtotal, total vBMD; Dtrab, trabecular vBMD; HC, healthy controls; HR-pQCT, high-resolution peripheral CT; Meta/Inn, ratio of meta-to-inner density; RA+, anti-citrullinated protein autoantibody-positive rheumatoid arthritis (RA); RA−, anti-citrullinated protein autoantibody-negative RA; Tb.1/N.SD, inhomogeneity of network; Tb.N, trabecular number; Tb.Sp, trabecular separation; Tb.Th, trabecular thickness; µFEA, micro-finite element analysis.