Table 2_High-precision universality? A matched-pair sawbone study on the learning curve, accuracy, and implant interchangeability of a novel open-platform robotic UKA system.docx

Learning curves were assessed by Cumulative Sum (CUSUM). Three-dimensional resection accuracy was quantified by high-precision laser scanning. Overall perceived workload was assessed with NASA-TLX.</p>Results<p>The precision CUSUM oscillated around zero for both operators (peak amplitudes +0.30 and −0.54 mm), indicating sub-millimeter accuracy from the first case without a detectable learning phase.

All 40 cases fell within the ±1 mm safe zone (P > 0.05 across resection depths). Tibial valgus deviation was greater in Operator B (1.74° ± 1.33° vs. 0.97° ± 0.96°; P = 0.028, Wilcoxon signed-rank test), and the mean deviation of both operators remained below the ±2° degree threshold. Operator B reached the operative-time inflection point earlier (Case 5 vs. 10) and reported lower NASA-TLX workload (32.05 ± 25.60 vs. 38.35 ± 23.72, P = 0.010); this difference cannot be attributed to workflow alone.</p>Conclusion<p>Under sawbone conditions—which cannot reproduce soft-tissue balancing, bleeding, anatomical variability, patient-specific deformity, or intraoperative decision-making—this two-operator exploratory evaluation found no evidence of compromised accuracy during alternating-implant workflows, with all 40 cases sub-millimeter.

Findings are hypothesis-generating pre-clinical observations requiring validation in adequately powered, multi-operator prospective studies before clinical inference.</p>