Increased deep pain sensitivity in persistent musculoskeletal pain but not in other musculoskeletal pain states.

BACKGROUND

Pressure pain thresholds (PPTs) in a non-painful body area are known to be affected in some chronic pain states. The aim of this study is to investigate PPTs in a pain-free body part in relation to pain persistence and intensity in patients with musculoskeletal pain.

METHODS

Patients with musculoskeletal pain were divided into three different pain groups: acute pain (pain duration<3 months, n=38), regularly recurrent pain (regularly recurrent pain duration>3 months, n=56), persistent pain (persistent pain duration>3 months, n=52) and a healthy control group (n=51). PPT measures were conducted over the tibialis anterior muscle on the right leg in all groups.

RESULTS

The persistent pain group showed significantly lower PPTs over the tibialis anterior muscle compared to controls. No significant differences were found between the acute and regularly recurrent pain groups compared to healthy controls. Significant correlations, albeit small, were found between pain intensity and PPTs.

CONCLUSIONS

Increased deep pain sensitivity was found in patients with persistent musculoskeletal pain, but not in regularly recurrent pain or in acute pain. Yet, a limitation of the study is that it did not have sufficient power to detect small levels of increased deep pain sensitivity among the latter groups when compared to healthy controls.

IMPLICATIONS: Knowledge about increased general hypersensitivity in persistent musculoskeletal pain could be important in clinical treatment.