A Novel Surgical Technique for Total Knee Arthroplasty Using the Femoral Trochlear Bisector as a New Landmark: Technical Description and Early Clinical Results

<b>Background/Objectives</b>: This study introduces and evaluates a novel surgical technique for total knee arthroplasty (TKA) that uses the trochlear groove bisector (TGB) as an anatomical landmark to achieve kinematic alignment of the femoral component in the coronal plane. The aim of the present retrospective observational analysis was to assess the reproducibility and accuracy of this approach and to report preliminary clinical outcomes. <b>Methods</b>: Twenty-eight TKA procedures were performed using the TGB-guided alignment technique. Preoperative planning and postoperative assessments were conducted on long-leg weight-bearing radiographs to measure the agreement between planned and achieved alignment, analysed using Bland-Altman statistics. Functional outcomes were evaluated at 12 months with the Knee Society Score (KSS), Forgotten Joint Score (FJS), and patient satisfaction. <b>Results</b>: The mean difference between planned and post-operative mLDFA was -0.3° ± 0.65°, with a root mean square error (RMSE) of 0.7°, demonstrating high accuracy and reproducibility. Postoperative outcomes showed mean KSS (knee = 89.6, function = 91.4), FJS = 69.6 ± 12, mean flexion = 124.6°, and mean HKA = 178°. Ninety percent of patients reported being satisfied or very satisfied at 12 months. <b>Conclusions</b>: The TGB-based technique offers a reliable, easily applicable method for restoring native femoral alignment in TKA using standard instrumentation. It allows accurate prediction of postoperative alignment and achieves favourable early functional outcomes. While currently limited to moderate varus deformities, future developments integrating 3D or CT-based planning may extend its applicability to more complex cases.