No significant association between quadriceps tendon alignment and 1-year patient-reported outcomes following physiological total knee arthroplasty without patellar resurfacing.

Abstract

This study aimed to clarify the clinical relevance of quadriceps tendon alignment (QTA), focusing on the quadriceps tendon axial angle (QTAx), in patients undergoing 'physiological total knee arthroplasty (TKA)'. This concept combines unrestricted kinematic alignment (KA) with a medial pivot implant to alter as little as possible the individual knee anatomy and kinematics. It was hypothesised that QTAx would not significantly influence patient-reported outcomes. A retrospective cohort analysis was performed on 54 knees in 50 patients who underwent physiological TKA performed with a non-KA-optimised implant design and without patella resurfacing between September 2022 and April 2024. Patient-reported outcomes, including the Oxford knee score, forgotten joint score, patient's joint perception, pain visual analogue scale and satisfaction visual analogue scale, were evaluated before surgery and at 1 year postoperatively. QTAx was measured on preoperative computed tomography scans. Patients were categorised into three groups according to their QTAx angle: low (<mean -1 SD), middle (within mean ±1 SD) and high (>mean +1 SD). Significant improvements were observed in all patient-reported outcomes 1 year after surgery. QTAx demonstrated no significant correlation with any outcome. Clinical results did not differ significantly among the three QTAx alignment groups, although the high-angle group tended to show slightly better outcomes. Two patients (3.7%) underwent secondary patellar resurfacing for persistent anterior knee pain. This study found that variation in QTA, as assessed by QTAx, was not significantly associated with 1-year clinical outcomes following physiological TKA performed with a non-KA-optimised implant and without patellar resurfacing. Our findings suggest that specific surgical techniques to counteract high QTA may not be necessary within the context of physiological TKA. Level III.