Abstract Purpose In kinematically aligned total knee arthroplasty (KA‐TKA), the restoration of the native joint line is critical to achieving optimal functional outcomes. The conventional assumption of a uniform 2 mm cartilage thickness may lead to errors in distal femoral resections. This study aimed to evaluate whether systematic cartilage removal from the unworn femoral condyle improves the accuracy and consistency of distal joint‐line restoration. Methods A retrospective analysis was conducted on prospectively collected data from 374 patients who underwent primary KA‐TKA between March 2023 and March 2025 at a single institution. Patients were divided into two groups: Group A ( n = 187), where cartilage on the unworn femoral condyle was preserved, and Group B ( n = 187), where cartilage was removed before distal resection. All procedures used the same surgical technique and implant model. The lateral distal femoral angle (LDFA) was measured preoperatively and postoperatively on full‐length weight‐bearing radiographs. The LDFA restoration error was defined as the difference between postoperative and preoperative LDFA values. Group comparisons were performed using the Wilcoxon–Mann–Whitney U test and Levene's test for equality of variances. Results Group B (cartilage removed) showed a significantly lower LDFA restoration error (–0.12° ± 0.94°) compared to Group A (–0.35° ± 1.88°) ( p < 0.001). Levene's test confirmed a significantly reduced dispersion of LDFA error in Group B ( p = 0.027). A greater proportion of Group B patients achieved LDFA restoration within ±0.5° (52.9% vs. 38.5%) and ±1° (85.0% vs. 71.7%) of the target value ( p < 0.001 for both). Conclusions Removing cartilage from the unworn femoral condyle significantly enhances the precision and consistency of distal joint line restoration in KA‐TKA. This technical refinement may reduce alignment variability and improve reproducibility by addressing interindividual differences in cartilage thickness, which are often underestimated in standard practice. Level of Evidence Level III, retrospective comparative study.
Cacciola et al. (Wed,) studied this question.