A simple inclusion criteria combination increases the rate of cartilage loss in patients with knee osteoarthritis

Objectives: Selection of patients with KL radiographic grade 2 and 3 is widely used in clinical trials, but this approach could have some limitations. The purpose of this study performed on OsteoArthritis Initiative (OAI) data is to assess whether adding OARSI-JSN to KL grading could select a population with increased rate of cartilage loss. Indeed, KL is not compartment-specific and not uniformly graded amongst expert readers. OARSI-JSN is another established, compartment-specific grading scale that specifically captures the joint space narrowing from radiographs.

Design: 1019 knee radiographs data from the progression cohort of the OAI public database were used. Cartilage loss measured with magnetic resonance imaging was evaluated using change over 1 year from baseline in cartilage thickness in the central Medial Tibio-Femoral Compartment (cMTFC) in the KL_2-3 and KL_2-3+JSN_1-2 populations.

Results: The mean cMTFC cartilage loss over one year was -0.135 ​± ​0.29 ​mm (median ​= ​-0.095 ​mm) in the KL_2-3 population and -0.176 ​± ​0.29 ​mm (median ​= ​-0.140 ​mm) in the KL_2-3 +JSN_1-2 population.

Conclusions: OARSI-JSN appears to be an effective inclusion criterion to be considered in combination with the KL grade in future clinical trials testing the structural efficacy of DMOADs in a time window of 1-year as it contributes to identify knees in whom the disease progresses rapidly.