Prognostic factors in adults with knee pain in general practice

To predict the 1-year outcome of incident nontraumatic knee symptoms in adults presenting in general practice.

Adults age >35 years with nontraumatic knee symptoms (n = 480) were followed for 1 year. At baseline, data on knee symptoms and demographics were collected and a physical examination performed. Knee symptoms were assessed by self-report questionnaires at 3-month intervals. After 1 year the physical examination was repeated. Multivariate prognostic regression models of patient characteristics, symptom characteristics, and physical examination were used to predict persisting knee symptoms after 1 year. Areas under receiving operating characteristic curves (AUCs) were used to determine the predictive value of the model. To assess the added predictive value of symptom characteristics and physical examination, these models were added to the model of patient characteristics. The improvement was expressed as the difference between the 2 AUCs.

In the multivariate prognostic model of patient characteristics, age >60 years, educational level, kinesophobia, and comorbidity of the skeletal system were associated with persistent knee symptoms after 1 year (AUC 0.67). Of the symptom characteristics, history of nontraumatic knee symptoms, bilateral symptoms, and duration of symptoms >3 months were associated (AUC 0.73). For determinants of physical examination, crepitus of passive extension was associated (AUC 0.55). The added value of the symptom characteristics model to the patient characteristics model was 0.09 (AUC 0.76). Physical examination added no further value.

Symptom characteristics are the strongest predictors of persisting knee symptoms at 1-year followup. Physical examination has no added value in predicting persistent knee symptoms in general practice.