Arthroscopic Versus Open Brostrom for Ankle Instability

1. Introduction Ankle sprains are among the most prevalent lesions in the athletic and non-athletic population(1). Accounting to up than 14% of emergency visits and with an estimated year cost of more than U$6 billion, it has a high impact in the health care system(2,3). Approximately 10 to 40% of these cases will develop ankle instability. The most susceptive population are those with an erratic treatment and/or poor rehabilitation program(4). Over the past years, the open Brostrom Gould procedure has been state as the gold standard procedure for this specific group of patients. (5,6). (7,8). With the development and improvement intra-articular ligament reconstruction and repair for shoulder and knee, the possibility to perform the same type of procedure at the ankle has grown. Arthroscopic-assisted Brostrom techniques were first described by Nery et al and Corte-Real et al near the year 2010(9,10). Some authors proposed modifications to these original approaches, but the main surgery concept was maintained(11-14).. During the last few years, a good number of studies were able to present good clinical and functional results with this procedure(1,11,15-18). Ankle arthroscopy is a reliable procedure and has been indicated to evaluate and treat a great number of ankle pathologies over the past decades(19,20). Ankle impingement, osteochondral lesions and tibiotarsi arthrodesis are some of the conditions that have good literature support in favor for the arthroscopic approach(21). Also, its use, prior to an ankle ligament repair or reconstruction, is advocated and sustained by several studies(22-26). It allows a complete articular visualization, providing the surgeon with a definitive scenario when dealing with ankle instability. Cartilage lesions, impingement syndromes and loose bodies that could be neglected by subsidiary exams can be detected and treated arthroscopically. The intra-articular ligament reconstruction and repair is not novelty for others orthopedic areas. The development of the anterior cruciate ligament surgery went to from the open approach to the arthroscopic technique over the last decades until the least was proclaimed the gold standard(27,28). The Bankart lesion, a condition normally related to traumatic shoulder instability, has a similar history, although the arthroscopic approach wasn't able to produce superior general results when compared to its open counterpart (29,30). Advances in the "all-inside" ligament repair are taking place at the shoulder and hip segment as well, showing promising and solid outcomes(31,32). Despite all the solid results regarding the biomechanical profile and the clinical effects of the arthroscopic Brostrom, there is a gap in its bibliography when it comes to high-level studies. Only Yeo et al in 2016 were able to show similar results between the open and the all-inside procedures with one-year follow-up study (1). Lately, an attempt in producing on systematic review on the subject was published, but no clinical trials were found to be included(33). Herein, our objective is to evaluate the effectiveness of the arthroscopic Brostrom technique and compare it to the open Brostrom procedure regarding complications, function by the Cumberland Ankle Instability Tool (CAIT), the American Orthopedic Foot and Ankle Society score (AOFAS), the Foot Function Index (FFI) and the 36 Short Form Survey (SF-36). The primary hypothesis is that the arthroscopic Brostrom will mitigate pain and improve function as compared to the open approach.
2. Material and Method

2.1 Design, setting and recruitment

This will be a multicentric, with parallel groups, randomized clinical trial. The study will be conducted at São Paulo Hospital, a tertiary, teaching hospital fully affiliated with the Federal university of São Paulo (UNIFESP), and at Hospital das Clínicas, another tertiary, teaching hospital fully affiliated with the Federal university of Minas Gerais (UFMG).

Participants will be enrolled at both hospitals, which provide assessment and treatment to approximately 5 (five) new patients with ankle instability per week. They will be referred by local orthopedist doctors or health professionals. The information to these physicians will be delivered by e-mail addressed directly to them, as well as via posters exhibited in places containing orthopedic medical care (outpatient clinic, emergency room).

2.2 Inclusion Criteria

• Individuals must be older than 18 and younger than 65 years of age, both genders;
• Participants must be experiencing instability symptoms at the ankle over the last six months;
• Clinical diagnosis of ankle instability, defined as the presence of at least one previous ankle sprain associated with a current instability sensation by the patient and the presence of a positive anterior drawer test; the previous lateral ligament injury must be confirmed by Magnetic Resonance Imaging (MRI) findings.

2.3 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) or systemic inflammatory disease a (rheumatoid arthritis, spondylitis, Reiter Syndrome, etc.);
• Associated injuries, such as osteochondral lesions, tendon ruptures and fractures;
• Associated instability, such as syndesmotic and medial instability;
• Cavovarus foot;
• BMI over 35;
• Previous infiltration in the ankle over the six months preceding the initial assessment;
• Pregnancy;
• Any condition that represents a contraindication of the proposed therapies;
• Impossibility or incapacity to sign the informed Consent Form;
• History or documented evidence of blood coagulation disorders (including treatment with anti-coagulants, but excluding aspirin);
• Use of heart pacemaker;
• Presence of infectious process (superficial on skin and cellular tissue, or deep in the bone) in the region to be treated;

2.4 Sampling

The objective of this study is to right evaluate the efficacy of the Brostrom arthroscopic technique and compare it to the open Brostrom procedure in relation to the function by the American Orthopedic Foot and Ankle Society Score (AOFAS), the foot function Index (FFI) and o 36 Short Form Survey (SF-36).

Thus, considering a 7.2 million population in the city of Sao Paulo that fit the criteria of inclusion and/or exclusion (Source: Census 2010) and respecting an involvement index of 0.072% value (0.72 by 1000 Exposition, according to the Ankle Consortium). Therefore, the target population estimated for the study is 5,155 people.

Using the formula shown in appendix I to calculate the sample size with a 10% error, we estimated a sampling of 98. This sample quantity was defined according to the methodology expressed in appendix I, where, based in the central boundary theorem and the laws of large numbers, this sample size ensures that statistical analyses will be reliable.

2.5 Procedures

A written, signed and dated informed consent will be obtained from the subject before any study-related procedures are performed. The patients will have to fill out an initial questionnaire in order to be enrolled (Attachment 2). After that, the assistant doctor will do the physical diagnostic examination. Then, X-rays and the MRI procedures will take place, to complete the diagnostic assessment. The patient will be included in the protocol and duly randomized after the diagnostic confirmation and fulfilment of all the inclusion criteria and non-adequacy to the exclusion criteria.

The randomization sequence will be generated via computing software (http://www.randomizer.org/form.htm), producing a list from 1 - 98, and each number will be related to a sole treatment method. We will do a randomization with interchanged blocks, with the same number of patients in each group.

Each non-transparent, opaque, sealed envelope, numbered from 1 to 98, will contain either a paper with the word "open" or with the words "arthroscopic". 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 lateral ligament repair approach.

The evaluator doctor won't have access to the protocol test applied to each patient, and the surgeries (open or arthroscopic) will be conducted by different physicians. The patients in both groups will receive a large bandage at the operation site before every consultation, blinding the evaluator.

2.6 Interventions 2.6.1 Open Brostrom Approach

1. Period from diagnosis to intervention: up to 1 month.
2. Patient will receive a general anesthesia and a popliteal peripheral block. After surgical site preparation, the traditional arthroscopic portals will be performed.
3. An ankle arthroscopy will be held, to confirm the nonexistence of chondral lesions, medial instability or syndesmotic instability. The ankle will be cleaned, and all impingements removed. The proximal ligament insertion at the lateral malleolus will be debrided.
4. All the arthroscopic instruments will be removed. A lateral longitudinal incision will be held over the lateral capsule. The fibula apex, at the ATFL and CFL footprint, will receive a 3.0mm suture anchor (with two n2 high-resistant sutures).
5. The ligaments will be reattached with tension in a paints-over-vest fashion, using one suture for the ATFL region and one for the CFL region.
6. The incisions will be closed, and the patient placed in a post-operative boot. Weight-bearing will start at the 1st week (with the boot) and range of motion (ROM) will begin at the 3rd week (limiting inversion until the 6th week). Patients will be transitioned to an ankle brace at the 4th week.
7. Patients will be evaluated, and the questionnaires applied at the 3rd, 6th, 12th, 24th and 48th post-operative week.

2.6.2 Arthroscopic Brostrom Approach

1. Period from diagnosis to intervention: up to 1 month.
2. Patient will receive a general anesthesia and a popliteal peripheral block. After surgical site preparation, the traditional arthroscopic portals will be performed.
3. An ankle arthroscopy will be held, to confirm the nonexistence of chondral lesions, medial instability or syndesmotic instability. The ankle will be cleaned, and all impingements removed. The proximal ligament insertion at the lateral malleolus will be debrided.
4. The fibula apex (by arthroscopic view), at the ATFL and CFL footprint, will receive a 3.0mm suture anchor (with two n2 high-resistant sutures).
5. One suture will be passed at the most superior anterolateral capsular site and the other at the most inferolateral capsular site, respecting the safe zone between the superficial fibular nerve and the peroneal tendons. These maneuvers will be executed in a percutaneous and arthroscopic assisted technique. The ligaments will be reattached with tension using an arthroscopic knot.
6. The incisions will be closed, and the patient placed in a post-operative boot. Weight-bearing will start at the 1st week (with the boot) and range of motion (ROM) will begin at the 3rd week (limiting inversion until the 6th week). Patients will be transitioned to an ankle brace at the 4th week.
7. Patient will be evaluated, and the questionnaires applied at the 3rd, 6th, 12th, 24th and 48th post-operative week.

2.6.3 Adjuvant therapies

Both groups will be submitted to the same post intervention care program, and they will be advised to use the following adjuvant therapies according to the intensity of their symptoms:

Elevation Every patient will be oriented to perform limb elevation during the post-operative period.

Pain Killers

Level 1:

• Dipyrone 1g every 6 hours, in case of pain, or
• Paracetamol 750mg every 6 hours

Level 2 (in case the pain does not diminish with level 1):

• Tramadol 50mg every 6 hours, in case of pain, or
• Codeine 30mg every 6 hours, in case of pain. The patient must present, at each visit to the doctor, the daily annotation concerning the used sedative medication. The medication will be supplied to the patient after the intervention, with the respective orientation concerning its use. After the period of five days of sedation, in case the pain persists, the patient will be reassessed, to check the necessity of changing the medication. If after the sixth week assessment the pain is stronger than in the initial painful stage, the patient will have the option of either change the treatment or being excluded from the study.

2.7 Primary outcome

• Major complications such as dehiscence, neural damage, infection and re-rupture.

Significant difference between groups.

• Dehiscence: inability to heal the soft tissue coverage until the end of the 4th post-operative week.
• Peripherical nerve damage: hypoesthesia or paresthesia not solved until the end of the 6th month after the surgery.
• Infection: clinical signs infection or pus drainage at the wound that required the use of antibiotics.
• Re-rupture: an ankle sprain event during the follow-up.

2.8 Secondary outcomes

• CAIT
• VAS
• FFI
• AOFAS score
• SF-36
• Minor complications such as neuropraxia and prominent suture knots.

2.9 Subject Discontinuation

Subjects may be discontinued from the study at any time. Reasons for discontinuation include:

1. Voluntary discontinuation by the subject without prejudice to further treatment.
2. Development of Complex Regional Pain Syndrome or any huge inflammatory response.
3. Pain and function severe impairment.

2.10 Statistical Analysis: After collecting the information, we will characterize the relative frequency (percentages) distribution of the qualitative variables through the Equal Test of Two Proportions. For relationship between qualitative variables analysis, the Chi-Squared test will be used. If a correlation between quantitative covariables reveals necessary, the Pearson's Correlation Test will be used. For the quantitative covariant comparison (effect measurement), we will make use of the ANOVA test.

1. Discussion Chronic ankle instability (CAI) can be a consequence in up to 40% of ankle sprains. Considering that this type of trauma can occur in more than 10,000 Americans per day and consume more than U$6 billion in related costs per year, it's fair to say that we might be dealing with a worldwide public health challenge. Although this instability may be managed with conservative treatment, many patients will require surgical resolution due their demands and expectations.

In this scenario, the Brostrom-Gould technique has emerged as the standard procedure in ankle instability operative care. Based on sustained and long-term results, its open fashion still is the preferable procedure for most of the Foot and Ankle and Sports Traumatology surgeons. Meanwhile, orthopedic arthroscopic techniques have progressed over the past decades and at the end of this century's first decade, the all-inside ankle ligament reconstruction started to be performed and published.

A moderate number of surveys regarding these techniques in the past few years showed its efficacy and safety. Yet, there is no consensus concerning what is the best way to approach ankle instability when contrasting the open and the arthroscopic approach due the lack of quality comparative studies. Our research intends to try to answer this question by a randomized clinical trial with robust outcomes and a long follow-up.