Clinical Trial to Evaluate the Adjuvant Effect of Shock Wave Therapy in the Insertional Achilles Tendinopathy

Introduction: The insertional tendinopathy occurs in the Achilles attachment to the tuberosity of the calcaneus bone and up to 2 cm proximal to the tuberosity. It is generally associated to a traction enthesophyte (upper spur), to Haglund deformity (pump bump) and to pre and retro achilles bursitis. Nowadays, it is considered that its cause is multi-factorial, comprehending mechanical, vascular, neural and genetic factors. Historically, the disease´s initial treatment is based on motor physiotherapy, via the eccentric strengthening of the tendon. If, on the one hand, the results for non-insertional tendinopathy were encouraging, 82% of them being duly successful, the insertional tendinopathy, on the other hand, produced a rate of improvement ranging between 32 and 67% of the patients, according to the present studies.

The failure of the traditional treatment normally leads the patients to surgery frequently associated to complications, such as wound necrosis and tendon rupture. More recently, the therapy with shock waves is being used in the treatment of pseudo-arthrosis and several types of tendinopathy.

Several studies showed the above mentioned effects of the shock wave therapy may theoretically stimulate neovascularization and of the collagen production that, besides being important in the healing process, also permits several clinical usages, such as the skin healing treatment, the pseudo-arthrosis and several tendinopathies, including the Achilles insertional tendinopathy. The shock wave therapy is being progressively more studied. Recent works have presented good results with the technique however; the evidences are still insufficient to represent a consensus regarding the indication of this treatment.

The objective of the present study is compare the effectiveness of eccentric strengthening protocol with and without shockwave therapy considering the VISA-A.

Hypothesis: The shock wave therapy allied to the eccentric strengthening protocol presents better results that the eccentric strengthening associated to placebo.

Material and Method Design Double blind randomized clinical trial, with the use of placebo, in parallel groups Setting The study will be conducted at Hospital São Paulo - University Hospital of UNIFESP (HSP-UNIFESP), in the Orthopedics and Traumatology Department (DOT) and in CPRT - Centre of Tissue Research and Regeneration (DOT/EPM-UNIFESP); linked to a FINEP project regarding Shock Waves.

Inclusion Criteria: Older than 18 and younger than 65 years of age, both genders; Pain symptoms in the calcaneus tendon insertion region over the last three months; Clinical diagnosis: presence of pain at palpation of the tendinous insertion region in the calcaneus bone (and up to 2cm close to this region) and the occurrence of increase of the region´s volume; Indication of tendinopathy in the Ultra Sound done at the previous health center or by a certified doctor; Lateral X-ray view of the calcaneus, showing any of the associated conditions (Haglund, enthesophyte or intra-substantial calcification).

Exclusion Criteria: Previous surgery involving the affected foot or ankle; History or documented evidence of autoimmune or peripheral vascular diseases; History or documented evidence of peripheral neuropathy (nervous compression syndrome, tarsal tunnel syndrome).History or documented evidence of systemic inflammatory disease a (rheumatoid arthritis, spondylitis, Reiter Syndrome, etc.); Non-Insertional or mixed tendinopathy (insertional and non-insertional); Previous infiltration in the affected tendon over the six months preceding the initial assessment; Beginning of the present pain, due to a trauma; Gross or congenital deformity overweighting the triceps sural muscle, being the main aetiology of the present disease; Pregnancy; Any condition that represents a contraindication of the proposed therapies; Any physical or social limitation that makes the protocol continuation unviable; Impossibility or incapacity to sign the Free Informed Consent Form; History or documented evidence concerning the blood coagulation disorders (treatment with anti-coagulant, excluding aspirin); Use of heart pacemaker;

Sampling: calculation considers a standard deviation of 16.2; the clinical difference to be detected corresponds to 3,3 with sampling error of 5%. It was calculated considering 93 patients divided in two groups in a randomized way. The sampling amount was defined according to the methodology indicated in Attachment I, where, based on the Central Limit Theorem and Laws of Large Numbers, this sampling size guarantees the reliability of the statistics.

Randomization: The randomization sequence will be generated via computing software (http://www.randomizer.org/form.htm), producing a list from 1 - x, and each number will be related to a sole treatment method. Investigators will perform a randomization with interchanged blocks, with the same number of patients in each group.

Allocation: The patients will have to fill out an initial questionnaire in order to be selected (Attachment 1). After that, the assistant doctor will do the physical diagnostic examination of the patient. Then, the US and XRay procedures will take place, in order complete the diagnostic assessment. The patient will be included in the protocol and duly randomized after the diagnostic confirmation is done via anamnesis and physical examination, and also after completion of supplementary tests, signature of the Informed Consent Form, and fulfilment of all the inclusion criteria and non-adequacy to the exclusion criteria. The following data will be collected to do the epidemiological: analysis of the lesions and interventions: Body mass index, Sex, Age, Sports practice (Yes/No), Presence of Haglung Deformity (Y/N), and the Presence of Enthesophyte (Y/N). Each non-transparent sealed envelope, numbered from 1 to 93, will contain either a paper with the word "physiotherapy" or with the words "physiotherapy and shock wave". Each treatment method will have the same number of envelopes. The patients will be initially assessed individually, being randomized and allocated in the same way. The intervention procedures will be the same, with the same positioning and preparations, but differing regarding the existence of a support at the applicator head of the shock wave apparatus in the group of patients without shock wave.

Blinding: Neither the patient nor the evaluator doctor will have access to the protocol test applied to each patient.

The patient will be included in the study after the diagnostic confirmation is done by medical history and physical examination, and also after completion of subsidiary tests (US), signature of the Informed Consent Form, and fulfilment of all the inclusion criteria and non-adequacy to the exclusion criteria.

Intervention: Utilization of shock waves: Appliance of US gel on the region that will receive the shock wave; Appliance of radial shock waves with the BLT600 equipment (BTL Medical Technologies - Canada), the intensity being 2000 to 3000 pulses, 7 to 10Hz of frequency, and 1,5 a 2,5Bar of intensity per application; Appliance on the first day of treatment (D0) as described above, repeated on the second week after the first intervention (2nd week) and four weeks after the first intervention (4th week).

Group without Shock wave: Appliance of US gel on the region that will receive the shock wave; Placing of the apparatus´ therapeutic head with the support that blocks the shock wave propagation directly on the appliance field; Appliance of radial shock waves with the BLT600 equipment (BTL Medical Technologies - Canada), the intensity being 2000 to 3000 pulses, 7 to 10Hz of frequency, and 1,5 a 2,5Bar of intensity per application; Appliance on the first day of treatment (D0) as described above, repeated on the second week after the first intervention (2nd week) and four weeks after the first intervention (4th week).

Eccentric Exercises The groups will be submitted to Alfredson eccentric strengthening protocol for 12 weeks, starting on the same day of the first appliance. The exercises will be shown to the patients by the assistant doctor, and a booklet (Attachment 2) will be handed out, with detailed explanation concerning the protocol to be followed.

Secondary Conclusion: EVA (Visual Analogue Scale); AOFAS; SF-12; Algometry (pain threshold and VAS with 3kg) Follow up: The patients must return to the ambulatory for clinical assessment at 2 weeks, 4 weeks, 6 weeks, 8 weeks, 3 months and 6 months after the beginning of the protocol.

Assessment Scores: The questionnaires VISA-A, EVA, AOFAS and SF-12 will be applied in the first consultation. The patient will be also assessed with the same questionnaires at the intervals of 1, 3 and 6 months of the protocol.

Statistical Analysis: After collecting information we will define the results, with descriptive analysis for the quantitative variables (interval of 95% of reliability for the average/mean). The qualitative variables will require the Comparison of Two Proportions via relative frequency analysis. The Pearson Correlation will be used to check the relation between quantitative variables, and the Chi-Square test will be utilized in relation to qualitative variables. The ANOVA test will be used to compare the two techniques based on their average.