Research on the Association Between the Inclination of the Proximal Tibiofibular Joint Surface and Medial Compartment Knee Osteoarthritis

The nonuniform settlement of the tibial plateau has been introduced to explain the development of knee varus and medial compartment knee osteoarthritis. It is believed that the lateral support of the fibula to the tibial plateau leads to the nonuniform settlement and degeneration of the plateau bilaterally.

Bone mass decreases as part of the normal aging process. Varying degrees of settlement of bone mass exist in the load-bearing joints, such as the knees, hips, ankles, and spine. In the proximal tibia, the lateral support of the fibula to the lateral tibial plateau routinely leads to nonuniform settlement, which is more severe in the medial plateau than in the lateral plateau. The slope of the tibial plateau arising from nonuniform settlement results in a transverse shearing force, with the femoral condyle shifting medially during walking and sports. Furthermore, side-slip aggravates the nonuniform settlement of the tibial plateau, especially in the medial plateau. Accordingly, a cycle of increasing the load distribution in the medial compartment and nonuniform settlement occurs. This results in the load from the normal distribution shifting farther medially to the medial plateau and consequently leads to knee varus, aggravating the progression of medial compartment knee osteoarthritis.

However, the angle of inclination of the proximal tibiofibular joint surface in different individuals varied widely. The angle of inclination of the proximal tibiofibular joint may affect the nonuniform settlement of the bilateral tibial plateau.

This study aims to research on the association between the inclination of the proximal tibiofibular joint surface and medial compartment knee osteoarthritis. A sample size power analysis was conducted before the study, which revealed that a minimum of 39 subjects per group was needed to achieve statistical significance with two-sided α=0.05 and 1-ß=0.80 and an assumed mean differences between two groups = 65% of the standard deviation.

Participants will be recruited from the outpatient clinic of No.113 Hospital of Chinese People's Liberation Army, as well as advertising flyers within the clinic. Firstly, patients of the study group will be recruited. It is hoped that the number of males will be equal to the number of females. Then the controls will be recruited and matched for age (within 5 years) and sex to the cases.