Gait risk factors for disease progression differ between non-traumatic and post-traumatic knee osteoarthritis

To examine if relationships between knee osteoarthritis (OA) progression with knee moments and muscle activation during gait vary between patients with non-traumatic and post-traumatic knee OA.

This longitudinal study included participants with non-traumatic (n = 17) and post-traumatic (n = 18) knee OA; the latter group had a previous anterior cruciate ligament rupture. Motion capture cameras, force plates, and surface electromyography measured knee moments and lower extremity muscle activation during gait. Cartilage volume change were determined over 2 years using magnetic resonance imaging in four regions: medial and lateral plateau and condyle. Linear regression analysis examined relationships between cartilage change with gait metrics (moments, muscle activation), group, and their interaction.

Measures from knee adduction and rotation moments were related to lateral condyle cartilage loss in both groups, and knee adduction moment to lateral plateau cartilage loss in the non-traumatic group only [β = -1.336, 95% confidence intervals (CI) = -2.653 to -0.019]. Generally, lower levels of stance phase muscle activation were related to greater cartilage loss. The relationship between cartilage loss in some regions with muscle activation characteristics varied between non-traumatic and post-traumatic groups including for: lateral hamstring (lateral condyle β = 0.128, 95%CI = 0.003 to 0.253; medial plateau β = 0.199, 95%CI = 0.059 to 0.339), rectus femoris (medial condyle β = -0.267, 95%CI = -0.460 to -0.073), and medial hamstrings (medial plateau; β = -0.146, 95%CI = -0.244 to -0.048).

Findings indicate that gait risk factors for OA progression may vary between patients with non-traumatic and post-traumatic knee OA. These OA subtypes should be considered in studies that investigate gait metrics as risk factors for OA progression.