The effects of myofascial trigger point injections on nocturnal calf cramps

The purpose of this study was to elucidate the effects of injection at trigger points on pain and sleep disturbance in patients with nocturnal calf cramps (NCCs).

Patients with NCCs that occurred at least once per week and who had myofascial trigger points (MTrPs) on the gastrocnemius muscles were enrolled in the study for 9 months. At the first visit (T0), we measured the intensity of NCC pain on an 11-point numeric rating scale, recorded the frequency of NCCs, and calculated the Insomnia Severity Index (ISI). We then checked for MTrPs on the gastrocnemius muscles and injected 1-2 mL of 0.25% lidocaine into each of the trigger points. At 1 (T1), 2 (T2), and 4 (T3) weeks after the first visit, we repeated the process performed at T0.

Twelve patients completed the treatment schedule and attended the follow-up visits. Mean values of the numeric rating scale pain score, frequency of cramps, and ISI declined significantly at T1, T2, and T3 compared with baseline (all P < .01). Of 12 patients, 10 had clinical insomnia before treatment, and this number decreased significantly to 3 patients at T2 and 1 patient at T3 (P = .012 and P = .001, respectively).

These preliminary data show that injection at MTrPs in patients with NCCs not only alleviated pain and reduced the frequency of cramps but also lessened the severity of insomnia as measured by the ISI. A larger randomized controlled trial is needed to confirm these findings and determine whether the effect lasts over the long term.