[Pain evolution in patients with central sensitization and osteoarthritis after knee arthroplasty].

Introduction: In patients with knee osteoarthritis, a group of 30% has been identified with central pain sensitization (CPS). The aim is to analyze the persistence of CPS in patients after knee arthroplasty and its correlation with pain intensity, functionality, determining factors and to evaluate physical examination as an assessment instrument.

Material And Methods: Quasi-experimental before-after study of patients operated on total knee arthroplasty. The evolution of subjective variables (pain characteristics, painDETECT questionnaire, WOMAC and Numerical Rating Scale) and physical examination (thermal hyperalgesia, allodynia, hypoesthesia, algometry and goniometry) 3 months before and 3 and 6 months after surgery are analysed using repeated measures ANOVA test for the quantitative ones and Cochran's Q for the qualitative ones. Spearmen test was used for the correlation of the questionnaires, the PD-Q and exploration variables and for the multivariate model of the PD-Q with clinical determinants.

Results: Sixty-seven patients completed the study. The evolution of the quantitative and qualitative variables was significant, with a correlation between questionnaires. In the linear multivariate model of PD-Q, a significant relationship was obtained from personal history of flexion limitation, chronic musculoskeletal pain and the association between depression and time.

Conclusions: A significant percentage of patients with knee osteoarthritis after arthroplasty persisted with probable CPS, correlating with intensity and functionality. The limitation of mobility and previous chronic comorbidity could be determinants of CPS, with anamnesis and exploration being useful tools in consultation.