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Table 3 Patient characteristics according to ‘low’ SES score ≤ 5 (SES Low ) or ‘high’ SES score ≥ 6 (SES High )

From: Outcomes following large joint arthroplasty: does socio-economic status matter?

  Knee replacements (n = 1,016) Hip replacements (n = 835)
  SESLow(n = 335) SESHigh(n = 681) p SESLow(n = 263) SESHigh(n = 572) p
Mean ± SD or n (%) Mean ± SD or n (%) Mean ± SD or n (%) Mean ± SD or n (%)
Sex:       
  Female 236 (70.5%) 452 (66.4%) 0.19 147 (55.9%) 355 (62.1%) 0.09
  Male 99 (29.6%) 229 (33.6%) 116 (44.1%) 217 (37.9%)
Age (years) 69.1 ± 8.6 70.9 ± 8.5 0.002 67.8 ± 10.2 68.7 ± 9.8 0.19
BMI (kg/m2) 33.0 ± 5.7 32.1 ± 6.0 0.02 30.2 ± 5.1 29.7 ± 5.9 0.44
Obesity¥ 231 (69.0%) 410 (60.2%) 0.007 126 (47.9%) 245 (42.8%) 0.17
Aetiology:       0.09
  OA 312 (93.1%) 645 (94.7%) 0.5 222 (84.4%) 504 (88.1%)
  RA 22 (6.6%) 33 (4.9%) 17 (6.5%) 16 (2.8%)
  AVN 1 (0.3%) 3 (0.4) 16 (6.1%) 34 (5.9%)
  CHD - - 8 (3.0%) 18 (3.2%)
Contralateral joint replacement 102 (30.5%) 223 (32.8%) 0.46 64 (24.3%) 140 (24.5%) 0.97
Prosthesis type:    0.12 - - -
  Cruciate retaining 123 (36.7%) 277 (40.7%)
  Posterior stabilizing 195 (58.2%) 385 (56.5%)
  Ultra congruent 17 (5.1%) 19 (2.8%)
Patella resurfaced 108 (32.2%) 207 (30.4%) 0.55 - - -
Cementation:       0.82
  Uncemented - - - 48 (18.3%) 100 (17.5%)
  Hybrid 191 (72.6%) 426 (74.5%)
  Totally cemented 24 (.1%) 46 (8.0%)
Age-adjusted CCI* 1.7 ± 2.1 1.8 ± 2.2 0.55 1.6 ± 2.1 1.5 ± 2.1 0.70
Complication 64 (19.1%) 158 (23.2%) 0.14 67 (25.5%) 155 (27.1%) 0.62
Non-English speaking 52 (15.5%) 102 (15.0%) 0.82 29 (11.0%) 55 (9.7%) 0.54
Pre-op IKSSPain 5.7 ± 8.5 5.2 ± 8.1 0.35 - - -
Post-op IKSSPain 35.0 ± 15.3 35.3 ± 15.3   - - -
Change in IKSSPain 29.2 ± 16.9 30.1 ± 16.1 0.44 - - -
Pre-op IKSSFunction ** 36.7 ± 19.5 35.9 ± 19.6 0.57 - - -
Post-op IKSSFunction ** 58.0 ± 24.9 58.7 ± 26.3 0.65 - - -
Change in IKSSFunction ** 21.3 ± 23.1 22.8 ± 24.8 0.35 - - -
Pre-op PCS§ 27.9 ± 6.8 26.8 ± 6.0 0.008 26.9 ± 6.1 25.9 ± 5.2 0.012
Post-op PCS§ 37.8 ± 11.0 37.7 ± 10.6 0.88 39.7 ± 11.2 40.1 ± 11.0 0.58
Change in PCS§ 10.0 ± 11.3 10.0 ± 10.6 0.17 12.8 ± 11.7 14.3 ± 11.3 0.08
Pre-op MCS 47.2 ± 12.0 49.4 ± 11.6 0.005 45.6 ± 12.5 47.0 ± 11.8 0.11
Post-op MCS 50.9 ± 11.0 50.9 ± 10.9 0.99 51.5 ± 10.7 51.0 ± 10.8 0.54
Change in MCS 3.8 ± 12.9 1.5 ± 12.2 0.008 5.9 ± 13.3 4.0 ± 12.7 0.047
Pre-op HHSPain # - - - 11.9 ± 4.6 12.1 ± 4.6 0.72
Post-op HHSPain # - - - 38.2 ± 9.6 38.8 ± 8.7 0.34
Change in HHSPain # - - - 26.2 ± 10.3 26.7 ± 9.5 0.47
Pre-op HHSFunction ¢ - - - 17.1 ± 9.7 17.0 ± 8.8 0.93
Post-op HHSFunction ¢ - - - 34.3 ± 10.3 34.2 ± 10.9 0.89
Change in HHSFunction ¢ - - - 17.2 ± 11.3 17.1 ± 10.8 0.94
  1. Abbreviations: BMI Body Mass Index, OA Osteoarthritis, RA Rheumatoid Arthritis, AVN Avascular necrosis, CHD Congenital hip dysplasia, SES score Socioeconomic status score, CCI Charlson Comorbidity Index, IKSS Pain International Knee Society Pain Score, pre-op pre-operative, post-op post-operative, IKSS Function International Knee Society Function Score, SF12 Physical Short Form 12 physical component, SF12 mental Short Form 12 mental component, HHS Pain Harris Hip Pain Score, HHS Function Harris Hip Function Score.
  2. BMI - Body Mass Index (weight [Kg]/height [m]2).
  3. ¥Obesity defined as BMI ≥ 30.
  4. SES score – Socioeconomic status score, (0 to 10) with a higher score representing socioeconomic advantage.
  5. *CCI – Charlson Comorbidity Index (0–43, age adjusted), with a higher score indicating a greater comorbidity burden.
  6. IKSSPain – Knee Society Pain Score (0 to 50) with a higher score representing less pain.
  7. **IKSSFunction – Knee Society Function Score (0 to 100) with a higher score representing better function.
  8. §PCS - score of ≥ 50 indicates no impairment; 40–49 mild impairment; 30–39 moderate impairment; and < 30 severe impairment.
  9. MCS - score of ≥ 50 indicates no distress; 40–49 mild distress; 30–39 moderate distress; and < 30 severe distress.
  10. #HHSPain – Harris Hip Pain Score (0 to 44) with a higher score representing less pain.
  11. ¢HHSFunction – Harris Hip Function Score (0 to 47) with a higher score representing better function.