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Table 1 Demographics of study population

From: Outcomes of the rotating hinge knee in revision total knee arthroplasty with a median follow-up of 6.2 years

  The baseline Final follow-up
N of knees (patients) 125 119 41 39
Age (median, range) 71.7 31.2–95.3 67.1 42.0–85.1
Body mass index (median, range) 29.3 18.8–52.0 30.6 23.1–43.0
Follow-up, years (median, range) 6.2 0.0–12.7 7.3 4.0–12.7
Females (knees, %) 91 73% 30 73%
Number of previous knee surgeries (median, range)a 2 1–6 2 1–5
Indications for revision RHK (knees), N (%)
 Instability 54 43.2% 22 53.7%
 Prosthetic joint infection 26 20.8% 6 14.6%
 Loosening, wear and osteolysis 20 16.0% 3 7.3%
 Periprosthetic fracture 11 8.8% 3 7.3%
 Complication of the extensor mechanismb 7 5.6% 2 4.9%
 Malalignment 6 4.8% 4 9.8%
 Arthrofibrosis 1 0.8% 1 2.4%
Stability of patella preoperatively, N (%)
 Stable 66 52.8% 21 51.2%
 Subluxation 11 8.8% 3 7.3%
 Chronic dislocation 11 8.8% 5 12.2%
 Fragmentation/Demineralization 4 3.2% 2 4.8%
 Girdlestone/Spacer/Flap 4 3.2% 1 2.4%
 Fracture 3 2.4% 1 2.4%
Instability of knee, N (%)
 Antero-Posterior 47 37.6% 15 36.6%
 Medio-Lateral 82 65.6% 28 68.3%
Pre-revision bone defects (AORI, N (%))c
 Tibia
  grade 1 87 69.6% 30 73.2
  grade 2a 12 9.6% 5 12.2%
  grade 2b 11 8.8% 3 7.3%
  grade 3 15 12.0% 3 7.3%
 Femur
  grade 1 90 72.0% 34 82.9%
  grade 2a 10 8.0% 2 4.9%
  grade 2b 9 7.2% 1 2.4%
  grade 3 16 12.8% 4 9.8%
  1. aincluding the index primary operation and possibly the spacer procedure
  2. bincluding patellar ligament ruptures and impaired extensor mechanism
  3. cAccording to Anderson Orthopaedic Research Institute (AORI) classification.