Association Between Anterior Knee Pain and Soft Tissue Gliding of the Anterior Knee Region After Total Knee Arthroplasty: A Cross-Sectional Study.

Abstract

Objective(s): To investigate the relationship between impaired gliding in the anterior knee region and anterior knee pain (AKP) in patients after total knee arthroplasty (TKA).

Design: Cross-sectional study.

Setting: Orthopedic hospital.

Participants: Patients aged >60 years who underwent TKA between June and September 2023 without abnormal components or postoperative infections.

Interventions: Not applicable.

Main outcome measures: Ultrasonography visualized the anterior knee soft tissues (subcutaneous tissue [SC], patellar tendon [PT], and infra-patellar fat pad [IFP]) during maximal voluntary isometric knee extension. Particle image velocimetry analyzed the SC, PT, and IFP flow velocities, organized into time-series data. Correlation coefficients of flow velocity between the SC and PT and between the PT and IFP were calculated to define the gliding coefficient. We measured AKP during walking and stair ascent and descent. Furthermore, we investigated the correlations between gliding coefficients and AKP and identified factors contributing to AKP using multiple regression analysis. The relationship between gliding coefficients and patient-reported outcomes was explored.

Results: In total, 20 patients (mean age, 72.9years; postoperative period, 14.9weeks) were included. A significant positive correlation was observed between the SC-PT gliding coefficients and AKP. Multiple regression analysis identified the SC-PT gliding coefficient as a significant independent variable associated with AKP during stair descent. Additionally, the SC-PT gliding coefficients were found to have a significant negative correlation with patient-reported outcomes.

Conclusions: The impaired gliding between the SC and PT may contribute to AKP, specifically during stair descent. This finding suggests that soft tissue gliding plays a significant role in postoperative pain and activity limitations in patients who underwent TKA.