Complexity theory in the management of patients with musculoskeletal pain

Nonlinear systems are not susceptible to being investigated with reductionist methods. In this sense, complexity theory offers an alternative approach to quantify the importance of contextual factors (CFs) in the patient with musculoskeletal pain. The result of the positive (placebo) or negative (nocebo) use of FCs in the therapeutic setting could be responsible for a large part of a non-specific component of the efficacy of the treatment, directly affecting the quality of the results related to the patient's health (for example, pain, disability or satisfaction). In recent years, understanding of the value of these effects has increased. Despite growing interest, knowledge and awareness of them is currently limited and heterogeneous among physical therapists, reducing their translational value in the field of physiotherapy. The purpose of this essay is to present the perspective of the management of the patient with musculoskeletal pain from the complexity theory.