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Table 1 Demographic data of patients in the spacer-complication group (group A) and the no-spacer-complication group (group B)

From: Mechanical failure of articulating polymethylmethacrylate (PMMA) spacers in two-stage revision hip arthroplasty: the risk factors and the impact on interim function

Characteristics Overall (n = 31) Group A (n = 14) Group B (n = 17) p-value
Age, median (IQR), y 56 (50 to 71) 55 (41 to 59) 64 (52 to 77) 0.021
Male, n (%) 19 (61.3) 10 (71.4) 9 (52.9) 0.290
BMI, median (IQR), kg/m2 23.7 (22.1 to 27.7) 23.5 (21.9 to 29.4) 23.8 (22.6 to 25.7) 0.787
ASA class, n (%)        0.436
 2 11 (35.5) 6 (42.9) 5 (29.4)  
 3 20 (64.5) 8 (57.1) 12 (70.6)  
Prosthesis type, n (%)        0.895
 Bipolar 8 (25.8) 3 (21.4) 5 (29.4)  
 Primary 11 (35.5) 4 (28.6) 7 (41.2)  
 Revision 12 (38.7) 7 (50.0) 5 (29.4)  
Comorbidities, n (%)
 Diabetes mellitus 9 (29.0) 4 (28.6) 5 (29.4) 0.959
 Renal disease 3 (9.7) 2 (14.3) 1 (5.9) 0.431
 Liver disease 6 (19.4) 2 (14.3) 4 (23.5) 0.517
 Drug abuse 3 (9.7) 2 (14.3) 1 (5.9) 0.431
 Alcoholism 3 (9.7) 2 (14.3) 1 (5.9) 0.835
 Psychiatric disorder 2 (6.5) 2 (14.3) 0 (0) 0.107
Classification of PJI, n (%)        0.003
 Acute 10 (32.3) 1 (7.1) 9 (52.9)  
 Chronic 21 (67.7) 13 (92.9) 8 (47.1)  
1st stage
 Pre-op ESR, median (IQR), mm/hr 63 (30 to 91) 62 (28 to 96) 63 (30 to 76) 0.889
 Pre-op CRP, median (IQR), mg/dL 15 (6.3 to 73.0) 29 (9.2–95) 14.8 (5.9 to 55.7) 0.578
Approach, n (%)        0.031
 Posterior 23 (74.2) 13 (92.9) 10 (58.8)  
 Direct lateral 8 (25.8) 1 (7.1) 7 (41.2)  
Paprosky bone defect classification, n (%)
 Acetabulum        0.143
  I 14 (45.2) 5 (35.7) 9 (52.9)  
  II (A + B + C) 8 (25.8) 6 (42.9) 2 (11.8)  
  III (A + B) 9 (29.0) 3 (21.4) 6 (5.3)  
 Femur        0.977
  I 8 (25.8) 4 (28.6) 4 (23.5)  
  II 10 (32.3) 4 (28.6) 6 (35.3)  
  III (A + B) 11 (35.5) 5 (35.7) 6 (35.3)  
  IV 2 (6.4) 1 (7.1) 1 (5.9)  
Additional spacer exchange 13 (41.9) 6 (42.9) 7 (41.2) 0.953
 Recurrent infection 10   3   7   
Interim perioda, median (IQR), weeks 14.5 (11 to 32) 15 (10 to 20) 13.5 (11 to 27) 0.950
Reimplantationa
 Pre-op ESR, median (IQR), mm/hr 29.9 (11.5 to 47.0) 31.2 (14.5 to 46.0) 28.8 (8.3 to 55.5) 0.397
 Pre-op CRP, median (IQR), mg/dL 16.7 (1.32 to 5.5) 28.7 (1.83 to 6.1) 6.9 (1.0 to 5.7) 0.156
Follow-up perioda, median (IQR), months 29 (23 to 35.5) 29 (25 to 34) 30 (23 to 36) 0.948
  1. aOne patient in group A and one patient in group B had permanent spacer implantation without revision surgery and were excluded from calculation of the interim period, CRP/ESR before reimplantation, and duration of follow-up period
  2. IQR interquartile range, BMI body mass index, ASA American Society of Anesthesiologists, ESR erythrocyte sedimentation rate, CRP C-reactive protein, PJI periprosthetic joint infection