Widespread mechanical pain hypersensitivity as sign of central sensitization in unilateral epicondylalgia: a blinded, controlled study.

OBJECTIVE: The aim of this study was to investigate whether generalized deep tissue hyperalgesia exists in patients with chronic unilateral lateral epicondylalgia (LE).

METHODS: A total of 26 LE patients (10 males and 16 females, aged 25 to 63 y) and 20 healthy comparable matched controls (aged 26 to 61 y) were recruited and pressure pain threshold (PPT) was assessed bilaterally over the median, ulnar, and radial nerve trunks, the lateral epicondyle, C5-C6 zygapophyseal joint, and the tibialis anterior muscle in a blind design.

RESULTS: PPT was significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the lateral epicondyle, the C5-C6 zygapophyseal joint, and tibialis anterior muscle in patients with LE than healthy controls (all P<0.001). PPTs over those measured points was negatively related to current elbow pain intensity (all P<0.05). A more significant decrease in PPTs were present in females (all P<0.05).

CONCLUSIONS: This revealed a widespread mechanical hypersensitivity in patients with LE, which suggest that central sensitization mechanisms are involved in patients with unilateral LE. The generalized decrease in PPT levels was associated with elbow pain intensity, supporting a role of peripheral sensitization mechanisms in the initiation or maintenance of central sensitization mechanisms. In addition, females may be more prone to the development of generalized mechanical hypersensitivity.