Non-drug therapies for the secondary prevention of lower limb muscle cramps

BACKGROUND

Lower limb muscle cramps are common and painful. They can limit exercise participation, and reduce quality of sleep, and quality of life. Many interventions are available for lower limb cramps; some are controversial or could cause harm, and often, people experience no benefit from the interventions used. This is an update of a Cochrane Review first published in 2012. We updated the review to incorporate new evidence.

OBJECTIVES

To assess the effects of non-drug, non-invasive therapies for lower limb muscle cramps.

SEARCH METHODS

In August 2018 and May 2020, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, the World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, and reference lists of included studies. We imposed no restrictions by language or publication date.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) of non-drug, non-invasive interventions tested over at least four weeks, for lower limb muscle cramps in any group of people, except pregnant women. The primary outcome was cramp frequency. Secondary outcomes were cramp pain severity, cramp duration, health-related quality of life, quality of sleep, participation in activities of daily living, proportion of participants reporting lower limb muscle cramps, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias, and cross-checked data extraction and analyses according to standard Cochrane procedures.

MAIN RESULTS

We included three trials, with 201 participants, all 50 years of age and older; none had neurological disease. All trials evaluated a form of stretching for lower limb muscle cramps. A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps (measured on a 10 cm visual analogue scale (VAS) where 0 = no pain and 10 cm = worst pain imaginable) in people aged 55 years and older, compared to no intervention (mean difference (MD) -1.30, 95% confidence interval (CI) -1.74 to -0.86; 1 RCT, 80 participants; low-certainty evidence). The certainty of evidence was very low for cramp frequency (change in number of cramps per night from week zero to week six) comparing the stretching group and the no intervention group (MD -1.2, 95% CI -1.8 to -0.6; 80 participants; very low-certainty evidence). Calf stretching alone for 12 weeks may make little to no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older (stretching group median number of cramps in the last four weeks (Md) 4, interquartile range (IQR) 8; N = 48; sham stretching group Md 3, IQR 7.63; N = 46) (U = 973.5, z = -0.995, P = 0.32, r = 0.10; 1 RCT, 94 participants; low-certainty evidence). This trial did not report cramp severity. The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome (N = 24). It was not possible to fully analyse the frequency data and the scale used to measure cramp severity is not validated. No study reported health-related quality of life, quality of sleep, or participation in activities of daily living. No participant in these three studies reported adverse events. The evidence for adverse events was of moderate certainty as the studies were too small to detect uncommon events. In two of the three studies, outcomes were at risk of recall bias, and tools used to measure outcomes were not validated. Due to limitations in study designs that led to risks of bias, and imprecise findings with wide CIs, we cannot be certain that findings of future studies will be similar to those presented in this review.

AUTHORS' CONCLUSIONS

A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps in people aged 55 years and older, but the effect on cramp frequency is uncertain. Calf stretching alone compared to sham stretching for 12 weeks may make little or no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older. The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome. Overall, use of unvalidated outcome measures and inconsistent diagnostic criteria make it difficult to compare the studies and apply findings to clinical practice. Given the prevalence and impact of lower limb muscle cramps, there is a pressing need to carefully evaluate many of the commonly recommended and emerging non-drug therapies in well-designed RCTs across all types of lower limb muscle cramps. A specific cramp outcome tool should be developed and validated for use in future research.

Non-drug therapies for lower limb muscle cramps

BACKGROUND

About one in every three adults are affected by lower limb muscle cramps. For some people, these cramps reduce quality of life, quality of sleep and participation in activities of daily living. Many interventions are available for lower limb cramps, but some are controversial, no treatment guidelines exist, and often people experience no benefit from the interventions prescribed.

OBJECTIVES

To assess the effects of non-drug, non-invasive treatments for lower limb cramp.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (13 September 2011) using the terms: cramp, spasm, contracture, charley horse and lower limb, lower extremity, foot, calf, leg, thigh, gastrocnemius, hamstring, quadriceps. We also searched CENTRAL (2011, Issue 3), MEDLINE (January 1966 to August 2011) and EMBASE (January 1980 to August 2011) and the reference lists of included studies. There were no language or publication restrictions.

SELECTION CRITERIA

All randomised controlled trials of non-drug, non-invasive interventions trialled over at least four weeks for the prevention of lower limb muscle cramps in any group of people. We excluded, for example, surgery, acupuncture and dry-needling, as invasive interventions. We selected only trials that included at least one of the following outcomes: cramp frequency, cramp severity, health-related quality of life, quality of sleep, participation in activities of daily living and adverse outcomes.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials, assessed risk of bias and cross checked data extraction and analysis. A third author was to arbitrate in the event of disagreement. We asked the authors of five trials for information to assist with screening studies for eligibility and received four responses.

MAIN RESULTS

One trial was eligible for inclusion.  All participants were age 60 years or over and had received a repeat prescription from their general practitioner of quinine for nighttime cramps in the preceding three months. This review includes data from only those participants who were advised to continue taking quinine. Forty-nine participants were advised to complete lean-to-wall calf muscle stretching held for 10 s three times per day. Forty-eight participants were allocated to a placebo stretching group. After 12 weeks, there was no statistically significant difference in recalled cramp frequency between groups. No "significant" adverse effect was reported. Limitations in the study's design impede interpretation of the results and clinical applicability.

AUTHORS' CONCLUSIONS

There is limited evidence on which to base clinical decisions regarding the use of non-drug therapies for the treatment of lower limb muscle cramp. Serious methodological limitations in the existing evidence hinder clinical application. There is an urgent need to carefully evaluate many of the commonly recommended and emerging non-drug therapies in well designed randomised controlled trials.