Effects of low-level laser therapy and functional exercises in the treatment of chronic ankle sprain: A randomized controlled trial

Objective: Chronic ankle sprains can be described as a failure of the lateral ankle joint complex following an acute or recurrent ankle injury. It is estimated that 80% to 85% of ankle sprains and lateral ankle complex failures can be successfully treated with a functional ankle rehabilitation program. However, most previous functional training has focused on enhancing local ankle function, with less attention paid to the damaged tissue cells and to the systematic consideration of the human lower limb kinetic chain. The more comprehensive approach to combined therapy requires further research. The purpose of this study is to investigate whether low-level laser therapy (LLLT) combined with functional exercise, is more effective than functional exercise alone in treating chronic ankle sprain. At the same time, to observe the dose-response relationship of LLLT in the treatment of chronic ankle sprains. Methods: Thirty-three patients with chronic ankle sprains were randomly divided into three groups: exercise alone, low-dose laser plus exercise, and high-dose laser plus exercise, with eleven patients in each group. Two “laser groups” received laser irradiation at an intensity of 398 mW/cm2 and 796 mW/cm2 (doses of 119 J/cm2 and 239 J/cm2), respectively, which were applied to two acupoints of Ki 3 (Taixi) and Bl 60 (Kunlun), and two pain points of the ankle. The functional exercise program consisted of ankle resistance exercises, resistance kinematic chain exercises, heel raise exercises, and BOSU ball exercises. All patients received five treatments per week for four weeks. At the end of this treatment and at baseline, observing the changes in ankle pain, range of motion (ROM), muscle strength, and balance postural control, and evaluating the curative effects. Results: After the 4-week intervention, all groups showed significant improvement in outcomes (P < 0.05). The high-dose laser irradiation combined with functional exercise resulted in more significant improvements in the primary outcomes than the other two regimens (P < 0.05). However, there were no significant differences (P > 0.05) between the low-dose laser irradiation combined with functional exercise and functional exercise alone. Conclusion: 1) Systematic functional exercise can significantly reduce the pain of patients with chronic ankle sprains, meanwhile improves the ROM, muscle strength, and balance control of the ankle joint. 2) LLLT enhances the efficacy of functional exercise in the treatment of chronic ankle sprains. 3) The therapeutic effect of LLLT on chronic ankle sprains is related to the irradiation intensity, and the effects of 796 mW/cm2 irradiation being more effective than 398 mW/cm2 irradiation.