Analysis of the discordance between radiographic changes and knee pain in osteoarthritis of the knee.

OBJECTIVE

To analyze cross sectional data from the National Health and Nutrition Examination Survey (NHANES I) concerning 3 indicators of osteoarthritis (OA) of the knee: radiographic evidence of structural damage, self-reported knee pain, and self-report of a diagnosis of arthritis at any joint by a physician.

METHODS

Analysis of NHANES I data for 6880 persons ages 25-74 in the United States.

RESULTS

Radiographic stage 2-4 knee OA was found in 319 subjects (3.7%); only 47% of these individuals reported knee pain, and only 61% reported that a physician had told them that they had arthritis. Knee pain was reported by 1004 subjects (14.6%), only 15% of whom had radiographic stage 2-4 changes of OA, and 59% of whom reported having a diagnosis of arthritis by a physician. A report of arthritis diagnosed by a physician was given by 1762 subjects (25.6%), of whom only 11% had stage 2-4 radiographic knee OA and 34% reported knee pain.

CONCLUSION

Substantial discordance exists in this population based study between radiographic OA of the knee versus knee pain, versus a diagnosis of arthritis by a physician. These phenomena may be important in the design of clinical research studies, as well as in criteria for OA.