Sagittal-Plane Knee Moment During Gait and Knee Cartilage Thickness

Context: Understanding the factors associated with thicker cartilage in a healthy population is important when developing strategies aimed at minimizing the cartilage thinning associated with knee osteoarthritis progression. Thicker articular cartilage is commonly thought to be healthier cartilage, but whether the sagittal-plane biomechanics important to gait are related to cartilage thickness is unknown. Objective: To determine the relationship of a weightbearing region of the medial femoral condyle's cartilage thickness to sagittal gait biomechanics in healthy individuals. Design: Descriptive laboratory study. Setting: Laboratory. Patients or Other Participants: Twenty-eight healthy participants (15 women: age = 21.1 +/- 2.1 years, height = 1.63 +/- 0.07 m, weight = 64.6 +/- 9.9 kg; 13 men: age = 22.1 +/- 2.9 years, height = 1.79 +/- 0.05 m, weight = 75.2 +/- 9.6 kg). Main Outcome Measure(s): Tibiofemoral angle (8) was obtained via goniometric assessment, thickness of the medial femoral condyle cartilage (mm) was obtained via ultrasound imaging, and peak internal knee-extensor moment (% body weight . height) was measured during 10 trials of over-ground walking at a self-selected pace. We used linear regression to examine the extent to which peak internal knee-extensor moment predicted cartilage thickness after accounting for tibiofemoral angle and sex. Results: Sex and tibiofemoral angle(12.3 degrees +/- 3.2 degrees) were entered in the initial step as control factors (R-2 = 0.01, P = .872). In the final step, internal knee-extensor moment (1.5% +/- 1.3% body weight . height) was entered, which resulted in greater knee-extensor moment being related to greater cartilage thickness (2.0 +/- 0.3 mm; R-2 Delta = 0.31, PD = .003). Conclusion: Individuals who walked with a greater peak internal knee-extensor moment during gait had a cartilage structure that is generally considered beneficial in a healthy population. Our study offers promising findings that a potentially modifiable biomechanical factor is associated with cartilage status in a healthy population. Establishing these baseline relationships in uninjured populations may help us to better understand potential factors related to maladaptive gait patterns that predispose a person to adverse changes in the cartilage environment.