Purpose: Functional alignment (FA) in total knee arthroplasty (TKA) prioritizes soft tissue balancing and anatomical restoration without systematic correction to neutral alignment. Most studies have focused on varus deformity, with little evidence available about FA in valgus deformity. The hypothesis of the present study was that FA in robotic‐assisted TKA for valgus deformity would demonstrate correction of the coronal alignment and yield satisfactory short‐term outcomes. Methods: This retrospective study included 58 patients with valgus coronal alignment (hip–knee–angle [HKA] ≥ 183°) who underwent robotic‐assisted TKA using the FA technique with a minimum of 1‐year follow‐up. Outcomes were assessed through the Knee Society Score (KSS), Oxford Knee Score (OKS), Forgotten Joint Score (FJS) and radiographic measurements of alignment and phenotypes. Complication and revision rates were also analyzed. Results: The cohort included 39 females and 19 males with a median age of 70. Post‐operatively, 86.2% of cases achieved coronal alignment within the safe zone (HKA 177–183°). Significant improvements were observed in KSS (part 1: 69.5–95, part 2: 65–94, p < 0.001), while OKS and FJS exhibited optimal outcomes. Two complications were recorded: one aseptic loosening (1.7%) and one early infection (1.7%). Kaplan–Meier survival analysis indicated favourable implant survivorship at a median follow‐up of 18 months. Conclusion: FA in image‐based robotic TKA is a safe and effective approach for patients with valgus deformity. This procedure resulted in a modest correction of the coronal alignment, where no soft tissue releases were needed. The majority of the cases fell within the target coronal alignment boundaries by only accommodating the individual laxities, suggesting the aim of FA to restore each knee's pre‐pathological alignment. Level of Evidence: Level IV.

In recent years, kinematic alignment (KA) is becoming a valid alternative to mechanical alignment (MA) in total knee arthroplasty (TKA). However, to avoid early failures, the restricted kinematic alignment (rKA) approach has been developed to restore native knee kinematics without reproducing extreme knee phenotype. This systematic review aims to evaluate clinical and radiological outcomes between rKA and MA for TKA. A systematic literature search was conducted following PRISMA guidelines on Pubmed, Scopus and Cochrane Library. The following search string was adopted: (((restricted kinematic) AND (mechanical)) AND (alignment)) AND (knee). We included studies that analyzed rKA versus MA in terms of clinical outcomes and complications with a minimum of 6 months of follow up. The following rKA- and MA-related data were evaluated: patient-reported outcome scores (PROMs), radiographic analysis of lower limb alignment, and complications. Criteria from the Methodological Index for Non-Randomized Studies were used to assess the methodological quality of the articles. This systematic review included seven clinical studies with a total of 892 knees (471 for MA group and 421 for rKA group, respectively). Overall, post-operative PROMs were similar between rKA and MA. Moreover, rKA reached better results regarding Forgotten Joint Score and post-operative patient satisfaction. Finally, no higher complication rate was observed with the rKA approach. The rKA aims to restore native knee kinematics, avoiding extreme deformities. Clinical outcomes are not inferior or even better for rKA compared with MA, without increasing the risk of short-middle-term implant failure. However, there is a high heterogeneity regarding the 'restricted' protocols used.

Introduction: Kinematic alignment (KA) in total knee arthroplasty (TKA) is by definition a pure femoral resurfacing procedure aiming to restore the individual prearthritic anatomy. However, when a 2 mm compensation is systematically used on the worn side, the variability in cartilage thickness in the unworn compartment might alter the accuracy of the technique. This study aimed to validate two intraoperative femoral cartilage thickness measurement techniques by comparing them to the photographic method, which measures cartilage thickness through pixel analysis of bone‐cut images. The study hypothesized that the two intraoperative methods are comparable and similarly accurate within 0.5 mm of the photographic method.Methods: Seventy cartilage thickness measurements from seventy patients with end‐stage knee osteoarthritis were prospectively collected. Two intraoperative techniques were evaluated: the electrocautery tip method (Method A) and the ruler method (Method B), performed before and after distal femoral bone resections, respectively. The postoperative photographic analysis (Method C) served as the reference method. Measurements were rounded to the nearest 0.5 mm for consistency. Data were analyzed using Kruskal–Wallis test, Wilcoxon rank‐sum tests, Spearman's rank correlation, percentage of agreement and intraclass correlation coefficients (ICCs).Results: No significant differences were observed between Method A and Method B in measuring femoral cartilage thickness. Agreement with Method C was 100% for Method B and 85% for Method A. In the 15% of discordant cases, Method A overestimated the measurements by one category of 0.5 mm compared to Method C. Correlation coefficients between the methods were high (ρ = 0.88−1.0). Intra‐ and interobserver reliability was high for all methods (ICCs 0.91–0.95).Discussion: Both intraoperative methods are reliable and comparable to the photographic method when rounded to the closest 0.5 mm, with no significant differences among them. The electrocautery method has the added advantage of measuring cartilage thickness before bone cuts are performed.Level of Evidence: Level IV.