In knee OA , strong evidence was found that avoidance of activities is associated with activity limitations via muscle weakness ( mediation by muscle weakness ) , strong evidence was found for an association between muscle weakness and activity limitations , and weak evidence was found that pain and psychological distress are associated with muscle weakness via avoidance of activities ( mediation by avoidance ) .
In hip OA , weak evidence was found for mediation by muscle weakness ; and strong evidence was found for an association between muscle weakness and activity limitations .
The avoidance model in patients with knee and hip osteoarthritis ( OA ) hypothesizes that pain and psychological distress lead to avoidance of activities , and thereby to muscle weakness and activity limitations .
This paper systematic ally review s the scientific evidence for the validity of this avoidance model .
Which patientswith osteoarthritis of hip and/or knee benefit most from behavioral graded activity?
Our objective was to investigate whether behavioral grade d activity ( BGA ) has particular benefit in specific subgroups of osteoarthritis ( OA ) patients . Two hundred participants with OA of hip or knee , or both ( clinical American College of Rheumatology , ACR , criteria ) participated in a r and omized clinical trial on the efficacy of BGA compared to treatment according to the Dutch physiotherapy guideline ( usual care ; UC ) . Changes in pain ( Visual Analog Scale , VAS ) , physical functioning ( Western Ontario and McMaster Universities Osteoarthritis Index , WOMAC , and McMaster Toronto Arthritis Question naire , MACTAR ) , and patient global assessment were compared for specific subgroups . Subgroups were assigned by the median split method and were analyzed using analysis of covariance . Beneficial effects of BGA were found for patients with a relatively low level of physical functioning ( p?0.03 ) . Furthermore , beneficial effects of BGA  in patients with a low level of internal locus of control were marginally significant ( p = .05 ) . Patients with a relatively low level of physical functioning  benefit more from BGA compared to UC . Compared to UC , BGA is the preferred treatment option in patients with a low level of physical functioning
In knee OA , strong evidence was found that avoidance of activities is associated with activity limitations via muscle weakness ( mediation by muscle weakness ) , strong evidence was found for an association between muscle weakness and activity limitations , and weak evidence was found that pain and psychological distress are associated with muscle weakness via avoidance of activities ( mediation by avoidance ) .
In hip OA , weak evidence was found for mediation by muscle weakness ; and strong evidence was found for an association between muscle weakness and activity limitations .
The avoidance model in patients with knee and hip osteoarthritis ( OA ) hypothesizes that pain and psychological distress lead to avoidance of activities , and thereby to muscle weakness and activity limitations .
This paper systematic ally review s the scientific evidence for the validity of this avoidance model .