The lateral ankle complex sprain is the most prevalent musculoskeletal injury among the general population and athletes and is associated with long-term pain, disability, and high healthcare costs. One of the complications of a lateral ankle sprain is the development of chronic ankle instability (CAI). Conservative treatment is the initial therapeutic option for patients with CAI, however, the best strategies are not yet clear. Clinically, a new invasive technique has appeared, known as echoguided Percutaneous Neuromodulation (EPNM). To date there are no studies showing the efficacy of the technique in patients with CAI together with the combination of a neuromuscular exercise program.

Participants: Volunteers and adults, from the group of students of the Gimbernat University School with a history of ankle sprain and physically active who meet the inclusion criteria.

Study variables: Self-administered ankle function scales (Cumberland ankle instability tool: CAIT and foot and ankle ability:FAAM measure Scale), objective measurement of function in the lower limb (Test countermovement jump: CMJ and Side hop Test:SHT), measurement of isometric strength of the ankle musculature, measurement of dynamic balance (Test star excursion balance), range of motion measurement (Ankle Dorsiflexion) and pain measurement (Numeric pain rating scale: NPRS Scale).

Procedures: After carrying out the assessment, the participants will be randomized to participate in a neuromuscular exercise intervention (control group) or in a neuromuscular exercise intervention together with an application of EPNM in the common peroneal nerve (control group). experimental). The duration of the intervention in both cases will be 3 weeks, where in the control group there will be 2 sessions per week of exercise and in the experimental group 2 sessions per week of exercise plus an application of EPNM.

Objective and hypothesis: The main objective of the study will be to compare the short- and medium-term effects of both interventions in relation to the study variables to be measured. The investigators hypothesize that those patients who receive neuromodulation combined with the neuromuscular exercise program will have greater improvements.

The lateral ankle complex sprain is the most prevalent musculoskeletal injury among the general population and athletes and is associated with long-term pain, disability, and high health costs. A review of ankle injuries on 70 analyzed sports established that lateral ankle sprains accounted for 77% of all injuries, where the highest incidence rates were found in sports characterized by running, changes of direction or running. jump like basketball, soccer or volleyball.One of the complications of lateral ankle sprain is the development of chronic ankle instability (CAI) characterized by repeated episodes or perceptions of ankle instability, persistent symptoms such as pain, swelling, and decreased function with limitations in activities of daily living and sports participation that persist more than a year after the initial injury. Conservative treatment is the initial therapeutic option for patients with CAI, however, the best strategies are not yet clear. Numerous rehabilitation protocols to improve CAI-associated deficits have been examined. These range from simple progressive strength work or postural dynamic balance protocols to multi-component (strength, balance, mobility) rehabilitation approaches with effective results in improving strength. , balance and in function.Clinically, a new invasive technique has appeared, known as echoguided Percutaneous Neuromodulation (EPNM). This minimally invasive intervention consists of the application of percutaneous electrical stimulation (biphasic square wave electrical current) through an acupuncture needle, as an electrode located in the vicinity of the nerve or motor point of the muscle to be treated under the guidance ultrasound where the generation of structural and excitation changes in the nerve is hypothesized, which as a consequence produces a decrease in its sensitization. It is an accessible, safe and economical technique to treat musculoskeletal conditions by physiotherapists. To date, there is limited evidence regarding its use. EPNM has been applied to different pathologies with good therapeutic results, but its use together with the combination of a multicomponent neuromuscular exercise program has never been studied.The main objective of the study will be to compare the effects in the short and medium term of an intervention with EPNM in the common peroneal nerve together with an exercise program in relation to the variables pain, range of motion in the ankle, strength of the ankle musculature , dynamic balance and functionality both in performance and in self-reports in patients with CAI.

Participants:

Voluntary subjects and adults, from the group of students of the Gimbernat University School with a history of ankle sprain and physically active, defined as participation in moderate aerobic physical activity of at least 30 minutes 5 days a week, or vigorous aerobic intensity of at least 20 minutes 3 days a week, will be evaluated to see if they can participate and be included in the study.

Variables under study:

Principal:

Self-administered scales: FAAM and CAIT. NPRS scale.

Secondaries:

Side hop test. Countermovement jump test. Star excursion balance test. Range of motion. Ankle Strength.

Randomization:

After the initial evaluation, the patients will be randomly assigned to receive a neuromuscular exercise program (control group) or to receive a neuromuscular exercise program plus a EPNM of the common peroneal nerve (experimental group). The hidden estimate is performed using a computer generated random table of numbers created prior to data collection by an outside researcher. Individualized and sequentially numbered index cards will be prepared. These will be placed in sealed opaque envelopes and the second external investigator will open the envelope and proceed with the treatment according to the screen.

Each group will be treated by a clinical physiotherapist, who will be the main investigator of the study, with more than 15 years of experience in the management of lower limb musculoskeletal injuries and more than 10 years of experience in the management of invasive techniques and ultrasound evaluation.

The researcher in charge of processing the data will be blinded with respect to belonging to the groups and likewise the researchers who will carry out the assessments will be blinded with respect to the group display of the participant. Participants in this study will not be blinded to their assigned group. All participants will read and sign an informed consent prior to inclusion in the study and will be asked to lead a lifestyle identical to the one they led before the start of the study.

Procedures:

Neuromuscular exercise program:

The strength program includes a protocol for using Theraband ® according to that described by Kaminsky et al. Participants will sit on the floor with one end of the Theraband attached to a back protector and the other end attached around the metatarsal heads of the foot to be worked on. The knee will be in full extension and the Theraband will initially be stretched to 70% of its resting length, without taking resistance into account. Strength exercises with bands will include ankle movements (dorsiflexion, inversion and eversion). The progression of the program will include an increase in series (1-3 sets of 8-10 repetitions) and an increase in resistance each week of the intervention depending on the subject's symptoms. Plantar flexion will be performed through the standing heel raise exercise. To progress the exercise in the three weeks, body weight will be taken into account. Therefore, during the first week the exercise will be performed with 30-35% of body weight, the second week with 40-45% and the third week with 50-55%.

The balance exercise program will consist of performing a series of exercises in a closed kinetic chain in a standing weight-bearing position that will be progressed from bilateral to unilateral depending on the acceptance of the load. The exercises applied in the study will be the bilateral squat and the unilateral squat in single-leg support with the maximum possible range of motion. To take into account the progress throughout the three weeks, in the bilateral squat during the first week you will work with 25-30% of the body weight, during the second week with 35-40% of the body weight and during the last week with 45-50% of body weight. In the unilateral squat you will work with 40% of the weight used in the squat each week. 3 sets of 10 repetitions will be performed.In the second week, the unilateral squat series will be performed through a backward lunge on an unstable platform (foam mat). Finally, in the third week, again with respect to the backward lunge, a disturbance will be carried out by placing a resistance band on the ankle that will favor greater activation of the muscles and in the last session a maximum range work will be carried out using assistance with a suspension system (TRX) with a weight that implies a high effort in the scale of perceived effort (8-10 points). All of these exercises will focus on motor control of the ankle, which will increase the strength of the intrinsic muscles and adequately contribute to the stabilization of the joint.

Echoguided percutaneous neuromodulation (EPNM):

The experimental group, apart from the exercise program, will receive a session of EPNM in the common peroneal nerve of the affected lower extremity. The EPNM will be applied prior to the exercise program session. 3 interventions will be carried out, in a dosage of 1 per week. It will be done with the electrostimulator (ES-160 co.).The participant will be placed in a prone position with the foot outside the stretcher. The motor part of the common peroneal nerve that affects the innervation of the superficial peroneal nerve will be searched through an Ultrasound scanner with a high-frequency linear transducer (10 Hz). A dry puncture needle (0.25mmx0.40mm, Barcelona, Spain) will be inserted until it is close to the perineurium and a biphasic symmetric square wave electric current will be applied to the needle, with a frequency of 3 Hz, a width of pulse of 250 μsec and a maximum tolerable intensity, in order to cause visible muscle contraction, according to the protocol of other studies. Ten stimulations will be performed with a duration of 10 seconds, with a rest period of 10 seconds between each stimulation. The needle will remain stationary throughout the intervention and the skin will be previously cleaned with isopropyl alcohol and chlorhexidine.

Assessment and monitoring:

The variables under study will be evaluated at 3 different times: pre-intervention measurement, post-intervention (a week after the intervention), medium-term measurement (a month after the intervention).

Adverse effects:

All patients will be asked to report any type of adverse effect they may experience throughout the study and up to one month after completion. An adverse effect is defined as a medium-term sequelae with any symptom perceived as painful or unacceptable by the participant and requiring treatment. As the introduction of the needle in some patients may induce post-treatment discomfort, subjects will be notified to report any incident. The EPNM has adverse effects that are infrequent and not serious, such as post-puncture pain that usually lasts from a few hours to a few days of mild intensity, the possible appearance of a bruise that will be minimized thanks to the use of the ultrasound and with pressure techniques on the area, the irritation of the nerve that will be minimized by the use of the ultrasound again and finally the possibility of infection, for this reason a disinfectant will be used on the area before the technique and gloves of a only use.

The therapeutic exercise program has been subsequently used by other research groups and is very safe because it is an incremental program individually adapted in intensity to each subject. Potential adverse effects are also rare, where the most common may be increased ankle pain, which will be controlled with load adaptation, possible generation of late-onset muscle soreness, which usually has a peak duration of 48 hours and a possible fall with the work of instability and disturbance, which is minimized with the presence of the therapist controlling the session at all times.

Sample size calculation:

The sample size and power calculation were calculated using the G-Power 3.1.9.4 software (Heinrich Heine Düsseldorf University).The calculations have been based using an a priori analysis with a mixed F-Anova test for repeated measures, with a Cohen's d of 0.25, a 5% level of significance (α= 0.05), 80% statistical power, two groups and 3 repeated measures(64). The estimated sample size was at least 28 subjects, 14 for each group. A dropout rate of 5% was considered during follow-up, so 15 subjects were finally included per group.

Statistical analysis of data:

1. Descriptive data in mean, range and standard deviation.
2. Normal distribution/homoscedasticity of the data (See whether the data are parametric or non-parametric).
3. Mixed-model repeated measures analysis of variance ( ANOVA) will used to see the interaction between time-group in the different variables.
4. Calculate the effect size of the difference between pre and post on the different variables with the cohen's d calculation. A effect size less than 0.2 will be considered trivial, between 0.2-0.5 low, between 0.5-0.8 moderate and greater than 0.8 high.

Inclusion Criteria:

1. History of at least one major ankle sprain. The initial sprain must have occurred at least 12 months prior to study participation, be associated with inflammatory symptoms (pain, edema) and have generated at least one day of interruption in physical activity.
2. The most recent sprain must have occurred at least 3 months prior to study participation.
3. History in the injured ankle of "dropping the ankle" (at least 2 episodes in the 6 months prior to study participation) and/or repeated sprains (two or more sprains in the same ankle) and/or feelings of instability in activities of daily living or sports (score less than 24 on the Cumberland Ankle Instability Tool (CAIT).
4. Have a score of less than 75% in three or more categories in the Foot and ankle Outcome Score(FAOS) or a level of less than 80% in sports activities in the Foot and ankle ability measure (FAAM).
5. Pain on the Numeric pain rating scale (NPRS) above 3 points out of 10 in their physical activity.

Exclusion Criteria:

1. History of surgery in either of the two lower extremities that may interfere with the performance of the tests.
2. History of a fracture in either of the two lower extremities requiring alignment.
3. Acute injury to the musculoskeletal structures of other lower extremity joints in the previous 3 months, which impact joint integrity and function, resulting in at least one day of loss of physical activity.
4. Chronic concomitant pathology at the level of the lower extremity (for example: osteoarthritis, vascular disease, neural pathology).
5. Regular use of analgesic medication that may mask symptoms.
6. Contraindications of percutaneous puncture and specific to the execution of neuromodulation.
7. Being receiving physiotherapy or medical treatment during the intervention.
8. Being pregnant at the start of the study.

All of the individual participant data collected during the trial, after deidentification.

Immediately following publication. No end date.

Anyone who wishes to access the data

The statistical analysis investigator will be masked.