Clinical and radiographic characterization of three-dimensional gait profiles of patients with knee osteoarthritis.

BACKGROUND: Previous authors have utilized gait kinematics to categorize knee osteoarthritis patients into four distinct profiles: (1) flexed knee; (2) externally rotated knee; (3) stiff knee; and (4) knee varus thrust and rotational rigidity. However, the relationship between these gait profiles and patients' characteristics remains poorly understood. Thus, this study aimed to investigate whether differences in clinical and radiographic characteristics were associated with these four gait profiles.

METHODS: This cross-sectional study used available data from a previous biomechanical study. Data on the four gait profiles were collected from 42 patients with advanced knee osteoarthritis. Three-dimensional kinematics of the knee was recorded during gait using an optoelectronic system. Subjects were evaluated for knee strength, range of motion, tibial slope, femorotibial angle, radiographic severity, anthropometric measurements, and patient-reported outcomes. Multiple comparisons were made using Dunn's test. The level of significance was set at 5%, and the effect size was calculated.

FINDINGS: Body mass index (BMI) was the only variable associated with a specific gait profile: profile 4 (P = 0.01; effect size = P1 × P4: -0.62; P2 × P4: -0.41; P3 × P4: -0.40).

INTERPRETATION: Our findings suggest that most clinical and radiographic characteristics commonly measured in clinical practice did not differ significantly among knee osteoarthritis patients with the four different gait profiles. The only exception was a higher BMI noted in those with gait profile 4; however, it remains unclear whether it can cause varus thrust or rotation rigidity. The incorporation of three-dimensional motion analysis to identify gait profiles provided clinical insights beyond the limitations of traditional clinical assessments.