Role of relative intentional rotation of the femoral component in robotic-assisted primary total knee arthroplasty as a tool for the correction of medial flexion laxity.

Internal rotation of the femoral component (IR) is an often-overlooked strategy to manage axial malalignment (AXM) in total knee arthroplasty (TKA). Proximal femoral pathologies can result in altered femoral condylar rotation, creating torsional incongruity that standard alignment protocols fail to address. While IR has been traditionally avoided due to several risks, robotic-assisted TKA (RA-TKA) may enable precise correction of such deformities using IR. This study aimed to identify the clinical and radiological indications for using relative IR to correct AXM, and to determine whether this strategy achieved balanced flexion gaps with favorable outcomes in a preliminary series. A retrospective review analyzed 219 consecutive primary RA-TKAs performed between March 2024 and March 2025 using an imageless, saw-based robotic system. Demographics, preoperative imaging, intraoperative robotic data, and 1-year radiographic and functional outcomes were evaluated in cases that received ≥ 3° IR relative to the posterior condylar axis. Of the 219 knees operated on, 12 (5.5%) required relative IR ≥ 3° (mean 5.46 ± 2.65°; range 3–10°). Preoperative CT imaging in these cases showed excessive external rotation of femoral condyles (relative to the femoral head-neck axis). Balanced flexion gaps were achieved in all cases reducing from a mean 3.83 ± 2.78 mm to 0.71 ± 0.75 mm at final assessment. Oxford knee scores (OKS) improved from 19.5 ± 2.1 to 34.6 ± 1.4 at follow-up. No cases in this preliminary series reported issues of patellar maltracking or anterior knee pain at 1-year follow-up, and radiologic evaluation showed no signs of component loosening or accelerated wear at this early time point. Relative IR, guided by robotic assistance, appears to safely correct pathological AXM in select patients, achieving balanced flexion gaps and favorable short-term outcomes without early complications in this preliminary series. This approach may restore hip-to-knee rotational congruency in patients with proximal femoral pathology, challenging conventional ideologies about uniform external rotation. These preliminary findings require validation through prospective comparative studies with longer follow-up to confirm durability and generalizability.Level of evidence Level III (Retrospective Observational Study).