Screening for hip and knee osteoarthritis in the general population: predictive value of a questionnaire and prevalence estimates.

OBJECTIVE

To study the feasibility and validity of a two-step telephone screening procedure for symptomatic knee and hip osteoarthritis (OA) in the general population.

METHOD

The screening questionnaire was based on signs and symptoms, previous diagnosis of OA and validated OA criteria. A random sample of telephone numbers was obtained and, at each number, one person aged 40-75 years was included. A physical examination and knee or hip radiographs were offered when the screen was positive. A sample of subjects with negative screens was also examined. The diagnosis of hip/knee OA was based on the American College of Rheumatology criteria for signs and symptoms and Kellgren-Lawrence radiographic stage 2 or greater. Prevalence rates were estimated with correction for the performance of the screening procedure.

RESULTS

Of 1380 subjects, 479 had positive screens, among whom 109 were evaluated; symptomatic radiographic OA was found in 50 subjects, at the knee (n = 35) or hip (n = 20). Corrected prevalence estimates of symptomatic OA were 7.6% (6.4%-8.8%) for the knee and 5% (3.9%-6.1%) for the hip. The screening procedure had 87% (95% CI 79% to 95%) sensitivity and 92% (95% CI 91% to 93%) specificity for detecting knee OA and respectively 93% (95% CI 86% to 100%) and 93% (95% CI 92% to 94%) for hip OA.

CONCLUSION

This study establishes the feasibility of telephone screening for symptomatic knee/hip OA, which could be used for a nationwide prevalence study. Pain and previous OA diagnosis were the best items for detecting symptomatic OA.