Knee pain diagrams: correlation with physical examination findings in patients with anterior knee pain.

All new patients who presented with knee problems were asked to fill out standard knee pain diagrams before being evaluated. Completed diagrams were not seen by the examining physicians. After obtaining the history and performing the physical examination, one of four physicians marked an identical diagram with the areas of tenderness. Ninety patients with a provisional diagnosis of patellofemoral pain completed 109 (19 bilateral) pain diagrams. Evaluation of the diagrams was quantitated by division of the diagrams into nine zones. The researcher grading the diagrams was blind to whether the diagrams were drawn by the patient or physician. Patients marked an average of 4.23 zones per knee compared with 2.66 zones for physicians. In 88% (96 of 109) of the knees, the physician diagram included all or some of the zones marked by the patients. Eighty-five percent of all zones marked by physicians were included in patient diagrams. Eighty-six percent of negative patient zones correctly predicted a negative examination. Overall frequency of positive findings in each of the nine zones was consistent between patient and physician diagrams. A physician can be confident that findings of tenderness will likely be within zones marked by a patient on a standard diagram of the knee. Pain diagrams facilitate proper diagnosis by correctly directing attention to areas of tenderness in a large percentage of cases and provide an inexpensive and highly useful prediction of areas of anterior knee tenderness in patients with patellofemoral pain.