Evaluating Ligament Laxity Profiles Across Full Range of Motion in Total Knee Arthroplasty: Insights Into the Tibia‐First Technique

Alignment techniques in total knee arthroplasty (TKA) continue to evolve with advancements in implantation technologies. The recent possibility of reliably characterizing the soft‐tissue envelope has enabled the development of TKA alignment techniques such as functional alignment, which aims to restore constitutional alignment while achieving proper soft‐tissue balance. Although these techniques offer guidelines for bone cut parameters in terms of alignment boundaries, the definition of laxities remains unclear. In this regard, this study focuses on tibia‐first TKA cases, evaluating laxity signatures when defining femoral cut parameters. This retrospective review analyzed 1762 TKA cases performed by 20 surgeons using a computer assisted orthopaedic surgery (CAOS) system. The cases were stratified based on the bearing type into three classes: posterior‐stabilized (PS), cruciate‐retaining (CR), and cruciate‐retaining constrained (CRC). Statistical analysis, including two‐way analysis of variance and post hoc Tukey multiple comparisons of the group means, demonstrated substantial surgeon‐to‐surgeon variability in intraoperative laxity profiles, irrespective of bearing type, compartment side, and tibial cut preference. This study highlights surgeon‐specific differences in laxity profiles derived during intraoperative femoral planning, emphasizing the need for patient‐specific guidelines to optimize TKA outcomes.