Table 1.
Comparison of UKA using PSI versus using conventional instrumentation for tibial resections
| 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 |
| Women | 6 (24%) | 15 (68%) | 0.002 | ||
| Right knee | 15 (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) | |||||
| Preoperative | 173.8 ± 2.9 | (167–178) | 173.6 ± 3.0 | (169–181) | 0.844 |
| Postoperative | 176.3 ± 2.8 | (170–183) | 177.1 ± 2.3 | (171–181) | 0.298 |
| Net change | 2.5 ± 1.5 | (−1–5) | 3.4 ± 2.4 | (−4–6) | 0.114 |
| mMPTA (deg) | |||||
| Preoperative | 83.1 ± 2.0 | (80–87) | 84.7 ± 2.0 | (81–88) | 0.012 |
| Postoperative | 85.6 ± 2.1 | (80–89) | 85.0 ± 3.6 | (78–92) | 0.509 |
| Net change | 2.4 ± 2.6 | (−2–7) | 0.3 ± 4.1 | (−7–7) | 0.045 |
Abbreviations: PSI patient specific instruments, BMI body mass index, HKA hip-knee-ankle, mMPTA mechanical medial proximal tibial angle, min minutes, deg degrees