Does knee pain in the community behave like a regional pain syndrome? Prospective cohort study of incidence and persistence

Palmer K T, Reading I, Calnan M, Linaker C and Coggon D

The aim of this prospective population-based survey was to investigate whether the increased incidence and persistence of knee pain is associated with low mood, somatising tendency, poor self-rated health and concerns about prognosis. At baseline, a sample of n=1798 working-aged subjects from the community, were sent a questionnaire asking about knee pain lasting 1 day in the previous 12 months, mental health (Short-Form 36), somatising tendency (components of the Brief Symptom Inventory), Self-Related Health and concerns about 12-month prognosis. At 18 months the subjects received a follow-up questionnaire asking about the nature of knee pain during the last 4 weeks, and whether it had been prescription treated. Logistical regression analysis of the data was utilised to determine the strength of association between incidence and persistence of knee pain. Seventy percent (n=1256) of the subjects responded to the postal follow-up, and of these n=468 had knee pain and n=788 were pain free, at baseline. Forty nine percent of patients with knee pain at baseline had persistent pain at follow-up. Fifteen percent of patients who were pain free at baseline had new pain symptoms. The odds of knee pain persisting was greater (1) for least versus most favourable bands of somatising tendency and Self-Related Health (2) if at baseline there was concern that pain would still be present at 12 months. It was concluded that knee pain in the community shares risk factors in common with other non-specific regional pain syndromes.

Annals of the Rheumatic Diseases, 2007, 66, 1190-1194

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