PLAIN RADIOGRAPHIC GRADING OF PRIMARY KNEE OSTEOARTHRITIS USING THE KELLGREN–LAWRENCE SYSTEM AND ITS CORRELATION WITH CLINICAL SEVERITY: A CROSS-SECTIONAL STUDY
DOI:
https://doi.org/10.48047/wynvn484Keywords:
knee osteoarthritis, Kellgren–Lawrence grade, WOMAC, radiographic severity, joint-space narrowingAbstract
Background: Primary knee osteoarthritis (OA) is a leading cause of pain and disability in adults. The Kellgren–Lawrence (KL) system is the most widely used plain-radiographic grading scheme, but the relationship between radiographic grade and clinical severity is variable and clinically important, since management decisions rest on both. Objectives: To grade primary knee OA using the KL system and its component radiographic features, and to correlate the radiographic grade with clinical severity (pain and function), at a tertiary care hospital in South India. Methods: In this hospital-based cross-sectional study, 250 patients with symptomatic primary knee OA underwent standardised (preferably weight-bearing) radiography of the index knee with KL grading and scoring of individual features (joint-space narrowing, osteophytes, subchondral sclerosis, cysts). Clinical severity was assessed by the visual analogue scale (VAS) for pain and the WOMAC index, and correlated with KL grade. Results: The mean age was 57.1 ± 9.3 years (63.6% female), with a mean BMI of 27.8 ± 3.7 kg/m² (78.8% overweight/obese); 50.8% reported occupational squatting/kneeling and 67.2% had bilateral symptoms. KL grade distribution was grade 1 in 10.4%, grade 2 in 38.8%, grade 3 in 33.6% and grade 4 in 17.2%; weight-bearing radiographs were used in 84.4%. Medial joint-space narrowing (≥grade 1) was present in 96.4% and osteophytes (≥grade 1) in 96.8%. The mean WOMAC total score was 53.6 ± 15.6 and mean VAS 6.1. Clinical severity rose steadily with radiographic grade: mean WOMAC increased from 32.7 (KL 1) to 46.1 (KL 2), 58.5 (KL 3) and 73.4 (KL 4), and KL grade correlated strongly with WOMAC (Spearman r = 0.76, p < 0.001) and with VAS (r = 0.75). Clinical severity was mild in 10.4%, moderate in 38.8% and severe in 50.8%. Conclusion: KL radiographic grade correlated strongly with clinical pain and functional severity in primary knee OA, supporting its role as a simple, informative bedside tool, though the imperfect concordance means that radiographic grade should complement rather than replace clinical assessment
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