Interobserver Reliability of the Kellgren-Lawrence Classification of Degenerative Knee Osteoarthritis among Resident Physicians from the University of the Philippines – Philippine General Hospital

  • Alfredo P. Pacheco
  • Gregorio Marcelo S. Azores
Keywords: Osteoarthritis, Arthritis, Knee, Kellgren-Lawrence


Objectives. To determine the interobserver reliability of the Kellgren-Lawrence classification among selected residents from departments forming the University of the Philippines – Philippine General Hospital (UP-PGH) Osteoarthritis Multidisciplinary Clinic (OAMDC).

Methods. From each department, 3 resident physicians (n = 9) were randomly chosen and tasked to categorize 20 knee anteroposterior and lateral radiographs into KLC grades. Inter-observer reliability was assessed using Fleiss’s kappa coefficient (κ).

Results. Results show that there was 31.90% (κ = 0.3190 ± 0.0228, p-value < 0.05) agreement beyond chance in KLC grading of the radiograph series among all participating residents. Sub-group analyses of interobserver reliability in terms of departmental affiliation noted a range of agreement beyond chance in KLC grading, from 10.52% (κ = 0.1052 ± 0.0779, p-value < 0.05) to 56.38% (κ = 0.5638 ± 0.0844, p-value < 0.05).

Conclusion. The findings reveal significant variability of agreement beyond chance in KLC grading, both within and among residents of UP-PGH OAMDC-participating clinical departments, which may reflect differences in training or competency and/or the documented limitations of the KLC system. Further investigation to improve diagnostic and severity assessment accuracy and uniformity in the institution is therefore warranted.


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