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Table 3 Distribution of differently affected tibial zones of stress shielding, according to Ewald [21] after implantation of a low contact stress (LCS) total knee arthroplasty (TKA)

From: Radiolucent lines in low-contact-stress mobile-bearing total knee arthroplasty: a blinded and matched case control study

  Relative numbers of affected „zones" of tibial stress shielding        
  Zone "1" "2" "3" "4" "5" "6" "7" Sum
RLL in patients with knee pain,
n = 27 (Figure 1)
31.6%* 16.2% 11.1% 26.6% 6.4% 4% 4% 100
RLL in matched patients without knee pain,
n = 6 (Figure 2)
25% 19.4% 12.9% 26.6% 12.9% 2.4% 0.8% 100
  1. Tibial zones of stress shielding were detected in 27 out 28 patients suffering from continual moderate knee pain (Figure 1, 3) and in 6 out of 28 age, sex, and follow-up matched pain-free patients (Figure 2). We present relative numbers of detected radiolucent lines (RLL) of a sum of four measurements by two observers with a minimum break of two weeks between. Accuracy of our measurements was evaluated with a "good" agreement of a Cohen' s kappa coefficient of p = 0.781.
  2. * These percentages show the actual relative number of a possibly affected number of a sum of four measurements by two observers.
  3. * Figure 3 shows an example of an anterior-posterior X-ray of a left Low-contact-stress total knee prosthesis (with cemented tibia) in a patient with continuous moderate knee pain with tibial stress shielding in zones "1", "2", "3", and "4".