A higher number of active trigger points (TrPs) was found to be associated with increased pain and related disability in patients with plantar heel pain, according to a study published in Pain Medicine.

The study included participants with unilateral chronic plantar heel pain (n=35) and matched comparable healthy controls (n=35). An assessor who was blinded to the participants’ conditions assessed TrPs in the flexor hallucis brevis, adductor hallucis, quadratus plantae, and internal gastrocnemius. The researchers used a 1 to 10 numeric pain rating scale, the Foot Function Index, and the Foot Health Status Questionnaire to assess pain and related disability, respectively.

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In participants with plantar heel pain, the number of TrPs was 4±3 (2.5±2 active TrPs, 1.5±1.8 latent TrPs). Healthy controls had only latent TrPs, with a mean of 1±1. Participants with plantar heel pain had more latent TrPs compared with healthy controls (P =.03). TrPs in participants with plantar heel pain were most commonly located in the quadratus plantae (n=20; 62.5%) and flexor hallucis brevis (n=19; 59%). A higher number of active TrPs — but not latent — was associated with higher foot pain (P <.01), higher impact of foot pain (P <.05), and worse related disability (P <.05).

“The current results provide further evidence in favor of the concept that active TrPs may be associated with plantar heel pain symptoms,” the researchers noted.

Reference

Ortega-Santiago R, Rios-Leon M, Martin-Casas P, et al. Active muscle trigger points are associated with pain and related disability in patients with plantar heel pain: a case-control study [published online April 15, 2019]. Pain Med. doi:10.1093/pm/pnz086