What are the clinical implications of knee crepitus to individuals with knee osteoarthritis? An observational study with data from the Osteoarthritis Initiative

Background: Crepitus is a common clinical feature of knee osteoarthritis. However, the importance of crepitus in the overall clinical presentation of individuals with knee osteoarthritis is unknown. Objective(s): (A) To compare function, pain and quality of life between individuals with knee osteoarthritis with and without crepitus; (B) to compare whether individuals with knee osteoarthritis in both knees, but crepitus in just one, differ in terms of function pain, and knee strength. Methods: Setting: Observational study. Participants: (A) A total of 584 participants with crepitus who had the same Kellgren–Lawrence grade on both knees were matched for gender, body mass index and Kellgren-Lawrence grade to participants without crepitus on both knees. (B) 361 participants with crepitus in only one knee and with the same Kellgren-Lawrence grade classification on both knees were included. Main outcome measure(s): A – Self-reported function, pain, quality of life, 20-m walk test and chair-stand test. B –Knee extensor and flexor strength, self-reported function and pain. Results: A – Individuals with crepitus had lower self-reported function, quality of life and higher pain compared to those without crepitus (3–11%; small effect = 0.17–0.41, respectively). No difference was found in objective function between groups. B – Self-reported function was lower in the limb with crepitus compared to the limb without crepitus (15%; trivial effect = 0.09). No difference was found in pain and knee strength between-groups. Conclusion(s): Individuals with knee osteoarthritis and knee crepitus have slightly lower self-reported physical function and knee-related quality of life (small or trivial effect). However, the presence of knee crepitus is not associated with objective function or knee strength.