Medial Compartment Knee Osteoarthritis Altered Tibiofemoral Joint Kinematics and Contact Pattern During Daily...

With the advancement of digital orthopedics, the growing prevalence of medial compartment knee osteoarthritis (MCKOA) and the widespread adoption of knee-preserving surgical techniques have heightened new interest in predicting the onset of MCKOA and promoting surgical outcomes. This study was to clarify the differences in kinematics and contact patterns between the MCKOA knee and its native sides during knee extension.

From March 2023 to June 2024, thirty-two patients who suffered from unilateral MCKOA, with their contralateral extremities asymptomatic and intact, were enrolled in this descriptive research. Three-dimensional models were created from computed tomography scans, and all patients performed continuous stair climbing under the surveillance of a dual fluoroscopic imaging system (DFIS) to determine the accurate 6-degrees-of-freedom (6-DOF) of their medial OA knees and the contralateral knees. The volume penetration centers between tibial and femoral cartilage models were defined as contact centers. All measured parameters were tested for significant differences using the Wilcoxon Rank-Sum test.

Compared to native knees, the MCKOA tibia showed increased flexion (mean 3.6°) and varus rotation (mean 1.6°), with more posterior (mean 1.4 mm), lateral (mean 1.2 mm) and proximal translations (mean 0.5 mm) relative to the femur during extension (p < 0.05). The tibiofemoral contact patterns on the medial and lateral tibial plateau of the MCKOA knee both shifted more medially (mean 1.4 mm and 1.3 mm, respectively, p < 0.05) than the native side, which was consistent with the lateral translations observed in 6-DOF.

Our findings offer valuable insights into the in vivo kinematics of MCKOA knee, its tibiofemoral joint (TFJ) and contact pattern. In MCKOA knees, the tibia exhibited increased flexion and varus rotation, along with more posterior, lateral, and proximal translation relative to the femur compared to the native side during extension. These changes aligned with the more medial shifts in contact patterns of the tibial plateau on the MCKOA side. These findings provide data support for the digital diagnosis and treatment of MCKOA.