Relationships between knee range of motion and Kellgren-Lawrence radiographic scores in knee osteoarthritis

Ersoz M, Ergun S: Relationship between knee range of motion and Kellgren-Lawrence radiographic scores in knee osteoarthritis. Am J Phys Med Rehabil 2003;82:110-115. Objective: To investigate the relationships between the joint range of motion and Kellgren-Lawrence radiographic scores of knee joint compartments in patients with knee osteoarthritis. Design: Forty knees of 20 consecutive bilateral, primary knee osteoarthritis patients were examined in the study. Maximal flexion, extension, and internal and external rotation were assessed using a goniometer. Kellgren-Lawrence radiographic scores were determined for medial tibiofemoral, lateral tibiofemoral, and patellofemoral compartments of the knee joint on lateral, tangential, and standing anteroposterior radiographs. Results: Statistically significant negative correlations were found between the range of motion and radiographic scores. Specifically, internal rotation was correlated with lateral compartment scores (r = -0.439, P < 0.01), and external rotation and flexion were correlated with medial compartment scores (r = -0.361, P < 0.05; r = 0.338, P < 0.05; respectively). Extension values were correlated with patellofemoral (r = -0.533, P < 0.01), medial (r = -0.456, P < 0.01), and lateral (r = -0.327, P < 0.05) compartment scores. Conclusions: A clear relationship is present between joint range of motion and Kellgren-Lawrence radiographic scores in knee osteoarthritis patients. Examination of the joint range of motion can give information about the compartmental distribution of the disease and help the physician focus on the compartment or compartments involved when performing diagnostic and therapeutic procedures. Evaluation of the compartments of the knee joint in radiographs can be informative about the joint range of motion in knee osteoarthritis.