The knee pain map: Reliability of a method to identify knee pain location and pattern

ObjectiveTo describe the location and pattern of knee pain in patients with chronic, frequent knee pain using the Knee Pain Map, and to evaluate the inter and intrarater reliability of the map.MethodsA cohort of 799 participants from the University of Pittsburgh Osteoarthritis Initiative Clinical Center who had knee pain in the last 12 months were studied. Trained interviewers assessed and recorded participantreported knee pain patterns into 8 local areas, 4 regional areas, or as diffuse. Inter and intrarater reliability were assessed using Fleiss kappa.ResultsParticipants most often reported localized 69 followed by regional 14 or diffuse 10 knee pain. In those with localized pain, the most commonly reported locations were the medial 56 and lateral 43 joint lines. In those with regional pain, the most commonly reported regions were the patella 44 and medial region 38. There was excellent interrater reliability for the identification of localized and regional pain patterns κ 0.7–0.9 and 0.7–0.8, respectively. The interrater reliability for specific locations was also excellent κ 0.7–1.0 when the number of participants with pain in a location was >4. For regional pain, the kappa for specific regions varied from 0.7–1.0.ConclusionThe majority of participants could identify the location of their knee pain, and trained interviewers could reliably record those locations. The variation in locations suggests that there are multiple sources of pain in knee OA. Additional studies are needed to determine whether specific knee pain patterns correlate with discrete pathologic findings on radiographs or magnetic resonance images.