Stimulation of muscles and proprioception after an ankle sprain
Compliance with self-training after an ankle sprain is very low and reduces the effectiveness of rehabilitation. How do we solve this dilemma?
Optimal rehabilitation after an ankle sprain requires more than 900 minutes of treatment. This can only be achieved through self-training. Compliance with self-training after an ankle sprain is very low and limits the effect of rehabilitation. How do we solve this dilemma?
Prevalence of ankle sprains
Ankle sprains are among the most common musculoskeletal injuries, highlighting the need for good prevention and treatment strategies to reduce the occurrence of new sprains and lower the risk of developing chronic ankle instability. The total prevalence of ankle sprains in Norway is estimated at 400 per day and 150,000–200,000 per year. Studies indicate that up to 70% of the population has experienced at least one sprain in their lifetime.
Many will experience at least one new ankle sprain within the first 12 months after the initial injury. A previous ankle sprain is therefore the most important risk factor for subsequent sprains, and many may develop chronic ankle instability if adequate rehabilitation is not provided. Ankle sprains are often considered minor, self-limiting injuries, leading many people not to seek treatment or receive insufficient follow-up from healthcare professionals.
Mechanoreceptors
Proprioception refers to the body's ability to perceive the position and movement of joints. This is made possible by mechanoreceptors in muscles, tendons, and ligaments, which continuously provide feedback to the central nervous system about body position and movement. Mechanoreceptors are specialized neurons that convert mechanical deformation into electrical signals. Stimulation of these receptors results in reflexive muscle contractions around the joint to help control movement.
In an ankle sprain, the mechanoreceptors in the ligaments become overstretched, raising their threshold for activation. It is therefore essential for optimal proprioception that mechanoreceptors in tendons and muscles compensate for joint position sensing until the ligament receptors return to normal function.
900 minutes of improvement through training
Rehabilitation after an ankle sprain begins as soon as the acute phase is over. A meta-analysis found that exercise interventions significantly reduce the likelihood of recurrent ankle sprains, and that this effect improves with over 900 minutes of treatment (OR = 0.48, 95% CI 0.37 to 0.63). This corresponds to 15 hours of training, which can be difficult to achieve through physiotherapy sessions alone. Most patients see a physiotherapist once or twice a week, meaning it can take two months or more to reach 900 minutes of rehabilitation.
To achieve the desired effect, training volume through self-exercise is absolutely necessary. The challenge with rehabilitation is getting patients to actually complete their self-training. Compliance with self-exercise has been shown to be very low. This has been discussed by Sevild et al. in Fysioterapeuten (January 2023), along with a summary of previous research.
Foot positioning, muscle stimulation, and proprioception
I believe patients should train more in daily life. An assistive device that places the foot in an inversion position may be a solution. This forces the individual to actively use the muscles on the outside of the foot to position the foot and ankle in a neutral position while walking. EMG measurements have shown increased activation of the lateral foot muscles in this context, with the purpose of stimulating proprioception.
