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Table 1 Comparison of UKA using PSI versus using conventional instrumentation for tibial resections

From: Patient-specific instrumentation does not improve tibial component coronal alignment for medial UKA compared to conventional instrumentation

 PSI (n = 25)Conventional (n = 22) 
mean ± SD
n (%)
(min–max)mean ± SD
n (%)
(min–max)p value
Patient demographics
 Age (years)65.1 ± 9.2(46–86)70.5 ± 9.2(52–85)0.050
 BMI (kg/m2)27.3 ± 2.9(21.3–32.2)26.4 ± 3.6(21–33)0.365
 Women6 (24%) 15 (68%) 0.002
 Right knee15 (60%) 12 (55%) 0.709
Intraoperative measurements
 Tourniquet time (min)58 ± 6(45–75)58 ± 9(50–90)0.55
Coronal alignment
 HKA angle (deg)
  Preoperative173.8 ± 2.9(167–178)173.6 ± 3.0(169–181)0.844
  Postoperative176.3 ± 2.8(170–183)177.1 ± 2.3(171–181)0.298
Net change2.5 ± 1.5(−1–5)3.4 ± 2.4(−4–6)0.114
 mMPTA (deg)
  Preoperative83.1 ± 2.0(80–87)84.7 ± 2.0(81–88)0.012
  Postoperative85.6 ± 2.1(80–89)85.0 ± 3.6(78–92)0.509
Net change2.4 ± 2.6(−2–7)0.3 ± 4.1(−7–7)0.045
  1. Abbreviations: PSI patient specific instruments, BMI body mass index, HKA hip-knee-ankle, mMPTA mechanical medial proximal tibial angle, min minutes, deg degrees