Previous studies shown that mechanical factors can be valuable biomarkers to help as a diagnostic aid, risk indicator of osteoarthritis (OA) progression and to be useful in guiding and monitoring treatments. Since the relationship between radiographic Kellgren-Lawrence (KL) grades and knee biomechanics and is not well understood, the study aims at assessing how knee kinematics differ with increasing KL grade.

This cross-sectional study was carried out in Quebec, Canada primary care clinics. Knee OA patients with KL grade≥2 and with pain≥4/10 were recruited. Sociodemographic characteristics and KOOS were compiled. In-clinic 3D knee kinematics was analyzed using the KneeKG™ system. ANCOVAs were performed on 11 kinematic parameters with age as a covariate due to statistical difference between KL4 and KL2 group. A Bonferroni correction was also applied (α=0.05/11=0.005).

Two hundred and ninety-four knee OA patients from 62 clinics participated in the study (62.2% women, mean age 63±9.2) (Table 1). KL grade of the most painful knee was equally distributed (34.4% KL2, 35.7% KL3 and 29.9 KL4). Half of participants had bilateral knee OA (52.0%), therefore, kinematic parameters was evaluated on 437 knees. Worst condition of KL4 group was confirmed by KOOS scores (Table 2). Flexion-extension motion during gait was significantly reduced, translating in a more stiff gait pattern, as KL grade increased. KL4 group also exhibited a strongly accentuated dynamic varus alignment and thrust during gait (Table 3).

Results show that knee function/kinematics of knee OA patients differ with increasing KL grade severity. This reinforces the value adding a functional assessment in the knee OA episode of care to personalize conservative treatment strategy as the progression of OA evolves.