The relationship between psychosocial variables and pain reporting in osteoarthritis of the knee.

Psychosocial factors may explain some of the variation in pain reporting among individuals with knee OA. This has important potential implications for management; indeed, several studies (reviewed in ref. 56) have demonstrated that interventions may reduce knee pain without apparent halting or reversing of structural damage. Such interventions have included the simple provision of support by monthly telephone calls (57), self-management programs (58), and cognitive-behavioral approaches designed to teach patients ways of coping with their pain (59). These programs are even more effective if the spouse is involved (60). It should be noted that there may be a large placebo effect in these interventions, and the degree to which patients are responding simply to an interest being taken in them and their problems is unclear; at least one study has shown that formal cognitive-behavioral therapy is no better than didactic education at improving pain and function in knee OA (though both are beneficial) (61). Many studies examining the role of psychosocial factors have suffered from poor design; many, for example, fail to control for radiographic severity. Future studies should define how pain is identified (dichotomous, ever/never/current, severity), differentiate community and hospital subjects, and separate patients by type and location of OA. Studies should also control for other factors potentially associated with pain: obesity, comorbidity, muscle weakness, and aerobic fitness. Prospective studies would allow clarification of the cause and effect relationship between anxiety, depression, and pain, both in the community and in patients who have elected to seek medical help. In this way, we may increase our understanding of the complex interaction between mood, social factors, and pain reporting in knee OA and, thus, improve the effectiveness, already equivalent to many pharmacologic interventions, of treatments designed to address psychosocial factors.