IS THE CONVENTIONAL KELLGREN–LAWRENCE GRADING SYSTEM STILL RELEVANT FOR ASSESSING KNEE OSTEOARTHRITIS?

Abstract

Background: Posterior tibia slope (PTS) and Metaphyseal diaphyseal angle (MDA) of knee joint tend to increase as the Osteoarthritis (OA) advances. These angles are being used in planning knee surgeries like Arthroscopy and Arthroplasty. Clinicians across the world rely on the Kellgren Lawrence (KL) grading system for knee osteoarthritis to evaluate disease severity and anticipate the likelihood of requiring knee replacement surgery. In this work, we studied the correlation of PTS and MDA with varying grades of knee OA with reference to the (KL) Grade to know whether KL grading can still be used in Out-patient clinics. There is limited published evidence exploring this correlation. Methods: This was a descriptive cross-sectional study conducted over a period of 18 months involving 76 patients over 40 years of age with knee pain showing radiological degenerative changes. Osteoarthritis of knee was graded as per the KL grading. PTS and MDA were calculated from radiographs of the knee joint. The correlation of these parameters with the Kellgren and Lawrence classification of OA and with each other was assessed. Results: Osteoarthritis (KL Grade) was distributed equally across grades 1, 2, 3, and 4, with 19 cases (25.00%) in each grade. Mean MDA was 22.24 ± 1.61°. Mean MDA was highest in grade 4 (24.25 ± 0.91°), followed by grade 3 (22.84 ± 0.64°), grade 2 (21.45 ± 0.57°), and lowest in grade 1 (20.41 ± 0.6°), with significant difference among grades (p value < 0.0001). Mean PTS was 12.43 ± 1.66°. Mean PTS was highest in grade 4 (14.59 ± 0.79°), followed by grade 3 (12.83 ± 0.6°), grade 2 (11.83 ± 0.77°), and lowest in grade 1 (10.46 ± 0.61°), with significant difference among grades (p value < 0.0001). A significant, very strong positive correlation was seen between MDA and PTS and each of them with KL grading of osteoarthritis for knee (P < 0.0001). Conclusions: Both PTS and MDA showed a statistically significant progressive increase with KL grading for OA of knee. The mean PTS and MDA values were found to increase consistently from KL Grade 1 to Grade 4, indicating a strong association between these anatomical parameters and the progression of degenerative changes in the knee joint. This indicates KL grade can still be used as clinical tool to assess OA of knee.