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.