The Effects of Coexisting Fibromyalgia Syndrome on Pain Intensity, Disability, and Treatment Outcome in Patients with Chronic Lateral Epicondylitis

Abstract

The objective of this study was to evaluate the effects of coexisting fibromyalgia syndrome (FS) on pain intensity, disability, and treatment outcome in patients with chronic lateral epicondylitis (LE). Seventy-eight patients with chronic unilateral LE and 30 healthy subjects were included. Patients were classified into two groups: group 1 consisted of 46 LE alone patients, while group 2 consisted of 32 LE plus FS patients. A pain questionnaire was used to determine the subjective pain and disability. Pressure pain threshold (PPT) on the lateral epicondyles, isometric hand grip strength (IHGS), lateral pinch grip strength (LPGS), and tender point examinations of groups were performed. A mixture of methylprednisolone and prilocaine was injected 1 cm distal to the lateral epicondyle. All measurements were repeated 2 weeks and 3 months after injection. Compared with healthy subjects, both patient groups had significantly increased pain and disability scores and decreased IHGS, LPGS, and PPT values (P < 0.001). Compared with the LE alone group, pain and disability scores were significantly higher (P < 0.01), and PPT, IHGS, and LPGS values were significantly lower in LE plus FS group (P < 0.05). Pain questionnaire scores of the LE alone and LE plus FS patients showed statistically significant decrease, and IHGS, LPGS, and PPTs showed statistically significant increase at the second week (P < 0.01) and at the third month (P < 0.001) after injection. Improvements in the LE plus FS group were poorer than FS alone group at both second week and third month after injection. Coexisting FS may increase the pain intensity and disability, and negatively affect the treatment outcome in patients with chronic LE.