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Table 3 Patient and surgical factors relating to the revision hip replacement procedure performed for ARMD

From: Adverse reactions to metal debris occur with all types of hip replacement not just metal-on-metal hips: a retrospective observational study of 3340 revisions for adverse reactions to metal debris from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

Co-variate

All ARMD revisions (n = 3340) (100%)

ARMD revisions in MoM hips (n = 3091) (92.5%)

ARMD revisions in non-MoM hips (n = 249) (7.5%)

p-value

Odds ratio (95% CI)

Gender

 Female vs. male

1,967 (58.89)

1,810 (58.56)

157 (63.05)

0.165

0.81 (0.62–1.07)

Age (in years)a

 Mean (SD)

64.2 (10.1)

64.0 (10.0)

67.5 (10.9)

<0.0001

 

  < 50

271 (8.11)

255 (8.25)

16 (6.43)

<0.001

Ref

 50–59

712 (21.32)

672 (21.74)

40 (16.06)

0.94 (0.51–1.72)

 60–69

1,292 (38.68)

1,214 (39.28)

78 (31.33)

1.17 (0.66–2.06)

  ≥ 70

1,065 (31.89)

950 (30.73)

115 (46.18)

2.34 (1.33–4.12)

BMI (in kg/m2)b

 Mean (SD)

29.0 (5.2)

29.0 (5.2)

28.5 (5.3)

0.285

-

Bilateral ARMD revisions

282 (8.44)

281 (9.09)

1 (0.40)

<0.001

-

Time from primary to revision (in years)a

 Mean (SD)

5.4 (2.1)

5.6 (2.0)

3.6 (2.9)

<0.0001

 

  ≤ 5

1,387 (41.53)

1,209 (39.11)

178 (71.49)

<0.001

Ref

  > 5

1,953 (58.47)

1,882(60.89)

71 (28.51)

0.23 (0.17–0.30)

ASA grade

 1

609 (18.23)

569 (18.41)

40 (16.06)

0.012

Ref

 2

2,389 (71.53)

2,219 (71.79)

170 (68.27)

1.01 (0.70–1.47)

 3 or above

342 (10.24)

303 (9.80)

39 (15.66)

1.70 (1.04–2.78)

VTE - chemical

 LMWH (+/-other)

1,798 (53.83)

1,644 (53.19)

154 (61.85)

0.002

-

 Aspirin only

92 (2.75)

80 (2.59)

12 (4.82)

 Other

1,155 (34.58)

1,093 (35.36)

62 (24.90)

 None

295 (8.83)

274 (8.86)

21 (8.43)

VTE - mechanical

 Any vs. none

3,189 (95.48)

2,957 (95.66)

232 (93.17)

0.069

-

Surgeon grade

 Consultant vs. other

3,201 (95.84)

2,963 (95.86)

238 (95.58)

0.833

-

Surgical approachb

 Posterior vs. other

2,691 (81.87)

2,516 (82.55)

175 (73.22)

<0.001

-

Revision type

 Single stage

3,266 (97.78)

3,034 (98.16)

232 (93.17)

<0.001

-

 Staged (2 or more)

71 (2.13)

54 (1.75)

17 (6.83)

 Excision arthroplasty

3 (0.09)

3 (0.10)

0 (0)

Revision indications/intra-operative findingsc

 1 indication

2,080 (62.28)

1,988 (64.32)

92 (36.95)

<0.001

-

 2 to 6 indications

1,260 (37.72)

1,103 (35.68)

157 (63.05)

 ARMD

3340 (100)

3091 (100)

249 (100)

NA

-

 Pain

665 (19.91)

618 (19.99)

47 (18.88)

0.671

-

 Aseptic loosening

338 (10.12)

278 (8.99)

60 (24.10)

<0.001

-

 Osteolysis

255 (7.63)

221 (7.15)

34 (13.65)

<0.001

-

 Implant malalignment

118 (3.53)

96 (3.11)

22 (8.84)

<0.001

-

 Other indications/findings

101 (3.02)

98 (3.17)

3 (1.20)

0.084

-

 Acetabular component wear

83 (2.49)

46 (1.49)

37 (14.86)

<0.001

-

 Dislocation/subluxation

67 (2.01)

41 (1.33)

26 (10.44)

<0.001

-

 Fracture

66 (1.98)

54 (1.75)

12 (4.82)

0.003

-

 Infection

43 (1.29)

33 (1.07)

10 (4.02)

0.001

-

 Liner dissociation

25 (0.75)

10 (0.32)

15 (6.02)

<0.001

-

 Implant fracture

18 (0.54)

7 (0.23)

11 (4.42)

<0.001

-

 Incorrect implant size

17 (0.51)

11 (0.36)

6 (2.41)

0.001

-

Revision procedureb,d

 All components revised

1,267 (38.79)

1,202 (39.62)

65 (28.02)

<0.001

-

 Cup (+/- head/liner/taper)

1,426 (43.66)

1,350 (44.50)

76 (32.76)

 Stem (+/- head/liner/taper)

144 (4.41)

107 (3.53)

37 (15.95)

 Head/ liner/taper revision only

422 (12.92)

370 (12.20)

52 (22.41)

Femoral head size (mm)b,d

 Mean (SD)

34.1 (3.3)

34.1 (3.2)

33.2 (3.7)

0.0003

-

 Range

22.25–48

22.25–48

22.25–40

 Median

36

36

36

 Inter-quartile range

32–36

32–36

32–36

  ≤ 32

1,180 (37.94)

1,073 (37.09)

107 (49.31)

0.001

 36

1,783 (57.33)

1,683 (58.17)

100 (46.08)

  > 36

147 (4.73)

137 (4.74)

10 (4.61)

Bearing surfaceb,d

 CoP

1,479 (47.6)

1,394 (48.4)

85 (38.1)

<0.001

-

 CoC

885 (28.5)

841 (29.2)

44 (19.7)

 MoP

736 (23.7)

642 (22.3)

94 (42.2)

 CoM

3 (0.10)

3 (0.10)

0 (0)

 MoM

2 (0.06)

2 (0.07)

0 (0)

 MoC

1 (0.03)

1 (0.03)

0 (0)

Cup fixationd

 Uncemented

2,355 (87.45)

2,239 (87.74)

116 (82.27)

0.057

-

 Cemented

338 (12.55)

313 (12.26)

25 (17.73)

Stem fixationd

 Uncemented

867 (61.45)

819 (62.57)

48 (47.06)

0.002

-

 Cemented

544 (38.55)

490 (37.43)

54 (52.94)

Bone graft (femoral)d

107 (3.20)

99 (3.20)

8 (3.21)

0.993

-

Bone graft (acetabular)d

650 (19.46)

611 (19.77)

39 (15.66)

0.116

-

Adverse surgical eventsd,e

64 (1.92)

48 (1.55)

16 (6.43)

<0.001

-

  1. ARMD Adverse reactions to metal debris, ASA American Society of Anesthesiologists, BMI Body mass index, CoC Ceramic-on-ceramic, CoM Ceramic-on-metal, CoP Ceramic-on-polyethylene, CI Confidence interval, HR Hip resurfacing, LMWH Low molecular weight heparin, MoC Metal-on-ceramic, MoM Metal-on-metal, MoP Metal-on-polyethylene, NA Not applicable; Ref Reference group, SD Standard deviation, THR Total hip replacement, VTE Venous thrombo-embolism
  2. Values in brackets are percentages unless otherwise indicated. Statistically significant differences between the two groups (p < 0.05) have been highlighted in bold text
  3. aAffect of age at revision surgery on outcome, and affect of time to revision surgery on outcome were non-linear so variables were grouped
  4. bMissing data for stated number of hips: BMI (n = 886); surgical approach (n = 53); revision procedure (n = 7); femoral head size (n = 156); bearing surface (n = 160)
  5. cIntra-operative revision findings refer to a problem with one or both hip components (loosening, fracture etc.)
  6. dAll details about the specific revision surgical procedures performed are provided for the 3266 hips (97.8% of the cohort) undergoing single stage revisions. Therefore details about 74 hip revisions undergoing either 2 or more stages, or excision arthroplasty procedures have not been included
  7. eIntra-operative adverse events included: calcar crack; pelvic and/or femoral shaft penetration; trochanteric and/or femoral shaft fracture; other
  8. - Co-variate was not included in multivariable logistic regression model as either it was a surgical factor that is part of the causal pathway, or there was significant missing data
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BMC Musculoskeletal Disorders

ISSN: 1471-2474

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