Association between pain catastrophizing, physical function and pain at first visit in the outpatient knee clinic.

Background: Pain catastrophizing has been associated with pain severity and disability in patients with knee osteoarthritis (OA). However, the literature is not consistent and other studies have failed to find this association. We examined the preoperative association between pain catastrophizing and physical function and pain, as well as the correlation between radiographic OA and physical symptoms and knee arthroplasty (KA).

Methods: This study was a cross-sectional study of all patients referred to the orthopaedic outpatient Knee Clinic from March to October 2013 with clinical symptoms of knee OA. Prior to clinical examination, the patients completed EuroQol-5D (EQ-5D), The Short Form-36 (SF-36 (PF)), The Oxford Knee Score (OKS) and The Pain Catastrophizing Scale (PCS). The severity of radiographic OA was graded with the Kellgren-Lawrence Scale (KLS).

Results: Of the 325 patients, 158 (48.6%) patients received a knee arthroplasty, 130 (40%) were treated conservatively, and 37 (11.4%) were scheduled for a knee arthroscopy. Mean age was 64.3 (SD 11.1) years and 53.9% were females. We found a strong correlation between PCS and OKS (r = -0.60, P = 0.000). Furthermore, the regression analysis showed statistically significant associations between PCS and both physical function and pain. We found no correlation between radiographic OA and physical function or pain.

Conclusions: Our results reveal that PCS is an important psychological factor when dealing with patients with OA. Furthermore, our results confirm the importance of a combined evaluation of symptoms, clinical examination, and radiographs when deciding on the right treatment for individual knee patients.