Paste yourAchilles tendinopathy is one of the most frequent encountered overuse injuries, especially in the athletic population.13 The incidence rate of Achilles tendinopathy in a general practice population is 2.35 per 1000 persons per year. The prevalence rate is 2.16 per 1000 persons per year.5
However chronic tendinopathy of the achilles tendon especially is found by middle aged male runners, it can affect the sedentary population as well.23
Tendinopathy was described by Cook as a pathological state of the tendon that results from repetitive loading or stress shielding that may lead to a catabolic effect on tendon integrity.
In recent years, there has been substantial investigation to understand tendon pathophysiology, which has led to a change in the treatment of tendon injuries and the management is shifted from a passive inflammation management only to active exercises and pharmalogical interventions.9,16
However, the fact that athletics with repetitive high loads on the achilles tendon has more than fifteen times chance to get an achilles tendon injury, the long-term prognosis and self-reported outcomes are good.23,34,42
Histological studies of Achilles tendinopathies have shown a disorganized collagen structure that is indicative of this process being a primarily degenerative, non-inflammatory condition. Achilles tendinopathy can be divided mainly into two types of injury
1. the midportion of the tendon (55–65% of injuries)
2. the insertion of the tendon (20–25%).23
The midportion Achilles tendinopathy (non-insertional)
The midportion Achilles tendinopathy in the acute phase arises from an inflammatory cellular reaction in the tendon with edema and circulatory impairment. This can worsen in adhesions and a more chronic condition. The primary symptom is pain, wich starts at the beginning of exercise. Clinical exam can induce pain on palpation (sensitivity 84), and pain is often located 2-6 cm above the insertion (Sensitivity 78%).31 While clinical exam is the primary component of diagnosis, imaging studies such as MRI and ultrasound are often utilized to confirm physical exam findings and indicates presence of a hypoechogenic area within the substance of the tendon.43
The most common treatments for chronic Achilles tendinopathies are activity modification, eccentric exercises, NSAIDs, injections and shock wave therapy. Non-insertional Achilles tendinopathies give positive results to these therapies.42 shows that only 29% of the patients is not returned to previous activities in an 8-year follow-up.
Eccentric exercises show in multiple studies that they give a positive result in the treatment of non-insertional Achilles tendinopathy. A 12 week during eccentric exercise program reduces pain during activities, normalizes the tendon structure and evanish the neovascularization.1 In addition, eccentric training was compared with a concentric exercise program and results that 82% of patients were able to return to normal activities after 12 weeks compared with only 36% who performed concentric exercises.6
The difference in result is due to an increase in load in eccentric exercises leading to structural tendon change. Unfortunately, several studies contradict each other and different authors propose the need for future research focusing on neural, biochemical, and myogenic changes as potential explanations for the therapeutic response of eccentric exercise.22 Injections are used to reduce pain and to produce local mechanical effects to decrease neovascularity.14 Both anesthetic and corticosteroids work effectively but must performed under ultrasound guidance to reduce the risks.37 Even with ultrasound guidance, there is still a risk of rupture when injecting around the Achilles, and the authors advise against injection of corticosteroids.
Insertional Achilles tendinopathy Insertional tendinopathy often occurs due to degeneration of the Achilles tendon fibers at the insertion and is often associated with older age, steroid use, obesity, diabetes, and inflammatory arthropathies.52 The pain is located at the midpoint of the calcaneus and is worse in the morning and causes severe pain the day after exercising.56 Radiographs shows often a prominent calcaneal tuberosity and/or calcification at the insertion site.20 As with mid portion tendinopathy, treatment is conservative and particularly walking uphill, or other activities which place stress on the Achilles insertion should be avoided. Shoe lifts can be used to reduce pressure on the heel bone.
Diagnostic
There is not always a clear and straightforward accurate diagnosis of an Achilles tendon injury.30,45 For screening and diagnostic tests, the sensitivity and specificity are used. The closer the sensitivity is to one hundred percent in the presence of a test with a negative result, the stronger the ability of that clinical measure to rule out the potential for a particular diagnosis. The closer the specificity is to one hundred percent in the presence of a test with a positive result, the stronger is the ability of that clinical measure to rule in the potential for a particular diagnosis.45
Diagnostic ultrasound and magnetic resonance imaging (MRI) are traditionally seen as criterion reference standards to diagnose achilles tendon injuries.45
In 2013 Hutchison described a standard protocol to diagnose achilles tendon injuries.30 He described to examine the musculotendinous junction to its insertion on the calcaneus
in both the longitudinal and transverse planes. The reference standard criteria for a tendinopathy was defined as the presence of hypoechogenic area within the substance of the tendon, with loss of normal, well organized, ribbon-like intratendinous echo structure or an increase of the anterior diameter of the tendon greater than 50% of the asymptomatic contralateral.30 Doppler activity can be used as objective outcome parameters for the treatment effect of achilles tendinopathy. A decrease in tendon thickness was statistically associated with a decrease in VAS palpation and VAS function.11,19
Treatment
One of the current treatments is Extracorporeal shockwave therapy (ESWT).55 ESWT is a non-invasive treatment in wich a device is used to pass acoustic shockwaves through the skin to the affected area. The shockwaves can be either focused or unfocused (often referred to as radial shock waves). The focused shockwaves are generated using electrohydraulic, electromagnetic or piezoelectric energy. The unfocused shockwaves are generated pneumatically.10
ESWT was originally used for treatment of renal stones and became popular in the last decade for treatment of different soft tissue disorders including calcifying tendinopathy in the rotator cuff, humeral epicondylitis and plantar fasciitis.15,27,28,40,54 The first systematic review that reports the effectiveness of ESWT for the treatment of chronic insertional and non-insertional Achilles tendinopathies suggests that it can be considered an alternative to surgery for patients who fail to respond to conservative treatment.4 Four of six studies reported statistic significant improvements in pain scores (VAS or NRS) and better functional outcomes (VISA-A, AOFAS, FIL and AHS). The same results are found in Gerdesmeyer (2015).26 The results and methods of the current studies are conflicting. Some authors included training while others did not. Since eccentric training has documented effect it must always be part of the intervention. 8,24,39,53
One of latest interventions for tendon injuries is Percutaneous Therapeutic Electrolysis (EPTE). It leads to a non-thermal electrochemical ablation through a catholic flow directly at the clinical focus of degeneration. EPTE causes an organic reaction leading to a highly localized inflammation, exclusively at the region of treatment that conduces to a rapid regeneration of the injured tendon.3
So far few research has been done on EPTE. The studies that have been carried out are of lower quality and often not statistically significant.2
In 2015 Abat shows a significant improvement in VISA-P outcomes after 3 months, 2 years, 5 years and 10 years, but there were no statistically significant differences observed in the results between any intermediate outcome measurements other than from baseline.3. In 2014 Valera-Garrido found significant difference in rating of pain intensity in the treatment of epicondylitis lateralis, but there were no statistically differences in tendon thickness.57
Given the limitations in current studies and no previous comparison between the two interventions, we investigated the effects of Radial shockwave therapy and EPTE in enhancing recovery of chronic and acute achilles tendinopathy. The primary aim of the study is to evaluate the progression on the Victorian Institute of Sport Assessment (VISA-A). The secondary aim is to evaluate the effect on pain measured with NPRS. The third aim of this study is to evaluate the effect on tendon thickness measured with ultrasound.
Materials and Methods
This is a factorial mixed design with quota sampling.
Participants
All patients with chronic and acute symptoms of achilles tendinopathy and who were more than 18 years old and able to comply were considered candidates for inclusion after giving their informed consent (appendix 1).
The patients were recruited at PMC Europark/Pasteurlaan. The criteria used for diagnosis as achilles tendinopathy were as follows: an area of swelling moving with dorsiflexion and plantarflexion of the ankle, tenderness in neutral position, pain in the achilles tendon, and tendon thickness based on ultrasound findings.
Exclusion criteria where rheumatoid arthritis, local infection, pregnancy, age younger than 18 years, pain and tenderness in the retro calcaneal bursa, calcifications in the Achilles tendon. Patients with a history of previous Achilles tendon surgery were also excluded.
Participation in the study was voluntary and the participants had the right to stop at any time. Data are only used for this scientific research. Names of the participants are not used in results or publications. The research was approved by “Le Comité Académique de Bioéthique” with file number B200-2018-067.
Measurement Devices
Outcome measures included Victorian Institute of Sports Assessment – Achilles (VISA-A), Numeric Rating Scale (NRS) and tendon thickness. The follow-up examinations where scheduled at baseline and after six weeks. The Visa-A questionnaire is a self-administered form that is commonly used to evaluate the severity of Achilles tendinopathy and to monitor outcomes after treatment. It has previously been shown to be valid, reliable (r= 0.90 to 0.93) and clinically relevant and is more specific than the classifications of Blazina and Curwin that have been developed in the past.12,18,32,46 VISA-A score is based on an inverted numeric rating scale (NRS) and results in a score range from 0 to 100 points.38 A minimal clinical important difference of 6.5 points was identified.38 On the numeric rating scale, 10 points indicate severe pain and 0 points indicated no pain. Several authors have used 50% pain reduction as a statistically significant reduction.51,59 In 2001 Farrar defined clinically important change in pain as ‘much improved’ or ‘very much improved’ using the Global Rating Scale, and that related to a 30% reduction in pain.25
Ultrasound examination
All the patients went through an US examination of the tendon using a Samsung Ultrasound HM70A with linear probe LA3-16AD. The linear transducer is used to minimize the problems of anisotropy.29
All investigations were conducted by the same examiner who has more than 5 years of experience in ultrasound and is Head of the Musculoskeletal Ultrasound program. The injured and the contralateral Achilles tendon were studied in all patients. Ultrasound was performed with the patient prone with the feet hanging free over the edge of the bench and tendon relaxed. The tendon was scanned longitudinally and transversally. The tendon maximal thickness was measured.
Measurement procedure
The registration is based on quota sampling. Patients were selected after they meet de selection criteria. Randomisation is performed by an external therapist. The measurements where performed at baseline and after six weeks of intervention. (Figure 1)
Treatment protocol EPTE
The EPTE technique described here should be performed with a specifically developed medically (EPI Advanced Medicine. Barcelona. Spain) Certified device. It produces an adjustable galvanic current through a negative flow to the treatment area, needles of 0.30mm in diameter and a modified electric scalpel are used. The intensity can be adjusted by changing both the duration and the milli-amperes that are administered. A thorough ultrasound inspection, as described by ultrasound examination, was performed to permit the identification of any existent neovascularization and changes in terms of structural improvement and decreased neovascularization obtained with the EPTE treatment. Preparation of the skin with alcohol before puncture is required despite the bacteriostatic action the device has. Subsequently, 3miliamps echo-guided punctures are made with the device to obtain controlled debridement of the injured tendon. The debridement was assessed with the sonographic images. After the first EPTE treatment, the patients underwent consecutive sessions of EPTE every week. Patients received US-guided EPTE treatment up to a maximum of six sessions. The treatment finished either when the patients were symptom free or after those six sessions.
Treatment protocol ESWT
The ESWT was applied using the Chattanooga 2074 Intelect – 203V RPW Unit wich produces radial shockwaves by propelling a projectile at high speeds against a second interface with compressed air. Patient is in suspine position and is affected foot is in dorsiflexion during the intervention. Ultrasound gel was applied liberally to the skin overlying the achilles tendon. The shock waves were delivered in a lateral to medial direction and a medial to lateral direction. The examiner felt the vibrations produced by the shockwaves along the contralateral side of the achilles tendon to confirm adequate dept of penetration. One session of high energy radial ESWT (Using 3000 pulses per treatment) were administered at weekly intervals. Frequency is set at 15Hz and bar ranged from 2,0 to 3,0 largely dictated by patient comfort. Patient underwent consecutive sessions of ESWT every week. Patients received ESWT treatment up to a maximum of six sessions. The treatment finished either when the patients were symptom free or after those six sessions.
Treatment protocol eccentric exercises
Both groups perform an eccentric exercise program during the six weeks of treatment. Both basic treatments, EPTE or with ESWT, were supplemented with the eccentric training program.
The eccentric training program was based on the previous study designs from Alfredson in 1998, Roos in 2003 and Alfredson & Cook 2007.6,7,50
Patients are instructed to do two exercises, that were demonstrated by the physical therapist. One exercise with bended knee and one exercise with extended knee.
To possibly diminish initial muscle soreness, the patients were instructed to increase the numbers of repetitions. In the first two days, they were doing 1 set of 15 repetitions, in day 3 and 4 they would increase to 2 sets of 15 repetitions and in day 5 till 7 they increase to 3 sets of 15 repetitions.
In the first week, they only had to do the exercise with extended knee, from week 2 they had to do both exercises, with extended and bended knee, both for 3 sets of 15 repetitions.
The patients were instructed also by a written manual how to perform the exercise and how to progress the exercise. The exercise has to be done as follows: from an upright body position and standing with all body weight on the forefoot and the ankle joint in plantar flexion lifted by the non-injured leg, the calf muscle is loaded eccentrically by having the patient lower the heel with the knee straight and the knee bent.6,7,50
Statistical Analysis
For the descriptive statistics, IBM SPSS Statistics software (v24, international Business Machines Corporation) was used. Screening for outliers was performed using boxplots generated by the software. QQ plot is performed to see that all variables were normally distributed and this is confirmed by the Shapiro Wilk test. Descriptive statistics were performed on the amplitude variables in EPTE and ESWT.
For the statistics of the amplitude variables a paired sample t-test was used to analyze the differences on the NRS, Visa-A questionnaire and tendon thickness after six weeks of treatment.
Comparising the intervention groups is done by an independent t-test with a split file on intervention using the difference between pretest and posttest.
The sample size was calculated on the basis of the VISA-A score. It was calculated for observations on the interval scale. The study was powered to detect a difference of 6,5 in the VISA-A score. Significance was set at 5%, Effect size at 0.8 and power was set at 80%. The estimated standard deviation of 6.5 of the VISA-A score was set to be equal to the minimum clinical important difference. The number of patients in each group was calculated to be 26. To compensate for any dropout, we planned to enroll 28 patients in each group.
The patients were randomized allocated to the 2 groups by an external physical therapist. The inclusion period was expected to last 3-4 months
Achilles tendinopathy with pain and dysfunction is a common overuse injury, most frequently seen in the athletic population.13 Not all interventions are equally successful.35 In this study, seven participants (4 men and 3 woman) were recruited with the diagnosis of Achilles tendinopathy. We compared two interventions (EPTE and ESWT) and measured the effect on pain (NPRS), dysfunction (VISA-A questionnaire) and tendon thickness (measured by musculoskeletal ultrasound).
There were no major differences between the two groups of patient at the baseline, all patients in both groups had tendinopathic symptoms.
The statistical analysis for each treatment separately revealed only significant difference on the VISA-A questionnaire in the EPTE intervention group. It seems to be that patients with achilles tendinopathy who underwent ETPE, scores better on the VISA-A questionnaire after the six weeks of treatment with EPTE and eccentric exercises than at baseline.
Both groups give improvement on pain (NPRS) and functional outcome (VISA-A), but this was not statistically significant. There were no differences in tendon thickness in both groups
The comparison between the two interventions gave no statistical significant differences on pain, dysfunction and tendon thickness after six weeks of treatment.
In the literature, there is much controversy about the treatment of achilles tendinopathy and the evidence of ESWT and EPTE.4,42,44,57
Several studies reported statistically significant improvement in pain scores (VAS or NRS) at a minimum of 4 months.36,48,49,58 Rasmussen et al showed no difference in the change of pain measure between ESWT and control.44
The same studies show a statistically significant improvement for functional outcome measures.4,42,44,57 All outcome measures for function were measured at a minimum period of 3 months from baseline. Costa (2005) reported no change in functional outcome measure.17
We used an eccentric training program based on the latest evidence.7,16,50 The effect of eccentric training is statistic significant proven in previous studies. There is lack of evidence when the intervention is combined with training.48
Little research has been done on EPTE. The reported outcomes were mostly described after 3 months, one year and two years. There were no statistically significant differences reported between any intermediate outcome.2 The limited number of studies and the lack of quality makes it difficult to compare. There is no consensus in methodology concerning the exercises after the treatment.3
Limitations
Because of the small sample size, the outcomes of this study must be interpreted with caution. Therefore, the statistical significant difference on EPTE, but also the other outcomes, may be due to the fact that not enough participants were recruited. Further studies should use a bigger sample size to be able to do more reliable statements.
For further research we recommend at least 26 participants. This to reach a power of 0.8 with an error of 0.05.
Besides the fact that a small population has been studied, the results are difficult to compare with the current evidence, given the fact that few results have been described after short term intervention. Most significant improvements were found at least after a three-month follow-up.36,58
In this study, we used an information guide with exercises that the patients have to perform at home. Beside the weekly appointments for their intervention (EPTE or ESWT) there was no control on their exercise program.
All the participants were regular people who were doing different jobs and have a different idea of using their free time. We chose to give the patients no limitations in their work and free time.
Participants with and without sports activities were includes, in a large age category. This all to get as much participants as possible.
These facts could lead to differences in load for the achilles tendon and maybe the effect of the treatment and the outcomes.
A smaller age category, more limitations and control could make the study more reliable, but is also more difficult to reach the power.
Conclusion
The purpose of this study was to evaluate the progression on the Victorian Institute of Sport Assessment (VISA-A), the effect on pain measured with NPRS and the effect on tendon thickness measured with ultrasound. Statistical significance was found on the VISA-A score from the intervention group with EPTE. They had a better functional outcome after six weeks of treatment compared to the ESWT group.
The results show a decrease for both interventions on pain, measured with the NRS. The results reported a bigger decrease on the NRS (rest and activity) for the EPTE group in comparison to the ESWT group. Although these results aren’t statistical significance, it could be indicative for results in the further research study designs.
The results on tendon thickness aren’t statistical significant as well, but shows us no difference on tendon thickness for the ESWT group, but an increase of thickness after six weeks for the EPTE group. Even though we expect based on the literature that less pain and less restriction in function should accompanied with a decrease of tendon thickness, we can’t conclude this with our outcomes. More research is necessary to conclude something about tendon thickness in relation to the achilles tendinopathy.
Because of the fact that the power was too low, it is only an indication, who needs to be further investigated. Also the fact that the other results were not statistical significant is only a trend. Because of the small sample size further research is essential to do reliable statements.
The results of this study suggest to use EPTE therapy above ESWT therapy for patients with achilles tendinopathy.