Hansen et al. Trials (2020) 21:399 https://doi.org/10.1186/s13063-020-04332-z STUDY PROTOCOL Open Access Individualized treatment for acute Achilles tendon rupture based on the Copenhagen Achilles Rupture Treatment Algorithm (CARTA): a study protocol for a multicenter randomized controlled trial Maria Swennergren Hansen1,2* , Marianne Toft Vestermark3, Per Hölmich2, Morten Tange Kristensen1,4 and Kristoffer Weisskirchner Barfod2 Abstract Background: An individualized treatment algorithm (Copenhagen Achilles Rupture Treatment Algorithm (CARTA)) based on the ultrasonographic appearance of an acute Achilles tendon rupture has been developed aiming to select the correct patients for operative and non-operative treatment. The objective of this study is to investigate if this individualized treatment algorithm gives a better functional outcome than treating all patients either operatively or non-operatively per default. Methods/design: This study is conducted as a multicenter, three-armed randomized controlled trial. Participants are included from four hospitals in Denmark and randomized 1:1:1 to one of three parallel groups: 1) Intervention group—participants are treated according to an individualized treatment algorithm; 2) Control group A— participants are treated non-operatively; 3) Control group B—participants are treated operatively. The individualized treatment algorithm for the intervention group is based on an ultrasonographic examination; tendon overlap and elongation below 7% is to be treated non-operatively, while no tendon overlap and/or elongation above 7% will be treated operatively. Over a period of 3 years, 300 participants will be included. The primary outcome is the heel- rise work test at 12 months post-injury. Secondary outcomes are tendon elongation, the Achilles tendon Total Rupture Score (ATRS), the rate of re-ruptures, and other complications. The primary analysis will be conducted as an intention-to-treat analysis. (Continued on next page) * Correspondence: [email protected] 1Physical Medicine and Rehabilitation Research – Copenhagen (PMR-C), Department of Physiotherapy, Copenhagen University Hospital, Kettegård Alle 30, 2650 Amager-Hvidovre, Denmark 2Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Kettegård Alle 30, 2650 Amager-Hvidovre, Denmark Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Hansen et al. Trials (2020) 21:399 Page 2 of 14 (Continued from previous page) Discussion: This trial will indicate if treatment of acute Achilles tendon rupture can be individualized based on elongation and tendon overlap. It is hypothesized that different patients will benefit from different treatments instead of offering all the same treatment. Trial registration: ClinicalTrials.gov, NCT03525964. Registered 16 May 2018. Background acute setting to functional outcome scores after 1 year Acute Achilles tendon rupture is an increasingly in non-operative-treated acute Achilles tendon rupture. common injury during both sports and recreational CALM was able to predict the final length of the tendon activities [1]. Numerous studies investigating opera- at one-year follow-up (manuscript in press). CALM is tive versus non-operativetreatmentwithafocuson the base of the newly developed Copenhagen Achilles re-rupture rate and complications related to the Rupture Treatment Algorithm (CARTA) together with treatment have been performed. Overall, non- examination of tendon overlap inspired by Amlang’s operative treatment results in a higher re-rupture classification system [14], which may be used as a pre- rate, which is argued to be acceptable due to the dictive tool for identifying patients at risk of critical lower rate of serious complications such as sural elongation of the tendon after healing and poor func- nerve damage and deep infections [2–6]. As a conse- tional outcome. A manuscript on CARTA has been sub- quence, recent studies have focused on refining non- mitted to a scientific journal. operative treatment of acute Achilles tendon rup- Based on CARTA we propose an evidence-based, indi- tures [7–9]. Simultaneously, standard treatment of vidualized algorithm for treatment of acute Achilles ten- acute Achilles tendon rupture has shifted from op- don rupture. The objective of this trial is to investigate if erative to non-operative in many Scandinavian de- this algorithm is superior to both operative and non- partments [1, 10], though the impact on functional operative treatment. outcome of this change toward non-operative treat- Hypothesis: Patients with acute Achilles tendon rup- ment is not yet clear [11, 12]. ture treated in accordance with the individualized treat- It is likely that some patients with primary Achilles ment algorithm (CARTA) will have a better limb tendon rupture need surgery and some are better off symmetry index for heel-rise-work compared to patients with non-operative treatment. This could be due to the treated either non-operatively or operatively per default. individual morphology of the ruptured tendon and the Null hypothesis: There is no difference in limb sym- potential to heal with good strength and a functionally metry index for heel-rise-work between patients treated acceptable length [13]. The identification and selection in accordance with the individualized treatment algo- of patients for operative treatment has not yet been well rithm (CARTA) and patients treated non-operatively or investigated [14, 15]. The clinical criteria for recom- operatively, respectively. mending operative treatment differ and have not been derived from evidence. Some clinicians would recom- mend operative treatment for young patients with high Methods/design functional demands and others would say that this This is a report of the second version of the trial proto- should be avoided if the patient has a poor prognosis of col dated 12 December 2018. Any important protocol healing based on comorbidities. These aspects clearly modifications will be addressed at ClinicalTrials.gov need to be taken into consideration but cannot stand (NCT03525964), to the Ethical Review board, and in the alone. A quantitative and evidence-based measure or Trials journal. The protocol was developed in accord- method is needed to guide the clinician for optimal ance with the guidelines and checklists for Standard treatment. Amlang et al. [14] have developed an ultra- Protocol Items: Recommendations for Interventional sonographic classification of Achilles tendon rupture but Trials (SPIRIT; Additional file 1) and Consolidated Stan- have not evaluated the length of the tendon or func- dards of Reporting Trials (CONSORT). tional outcome after healing, and the method demands an experienced examiner. Barfod et al. have developed and validated the ultrasound-based Copenhagen Achilles Design Length Measure (CALM), which can be conducted in The trial is performed as a randomized controlled trial the emergency department as part of the primary diag- with patients included from four hospitals in Denmark nosis [16, 17]. Barfod et al. have also investigated the (Copenhagen University Hospital Amager-Hvidovre, correlation of Amlang’s classification and CALM in the Hospital Little Belt Kolding, Viborg Regional Hospital, and Zealand University Hospital, Køge). The participants Hansen et al. Trials (2020) 21:399 Page 3 of 14 are individually randomized in a 1:1:1 order in blocks way; they have the same distal landmark but the stratified by hospital to one of three parallel groups: proximal landmark differs. CALM has shown good reliability and is recommended over other 1. Intervention group: Participants are treated measurements of elongation [17, 20, 21]. The according to an individualized treatment algorithm measure is performed as described by Barfod et al. 2. Control group A: Participants are treated non- but with the feet of the patient (laying in the prone operatively position) hanging free of the table instead of with 3. Control group B: Participants are treated 10° degrees of plantar flexion in the ankle joints as operatively originally described [16, 21]. Landmarks are identified and marked on the skin. The distal Objective landmark is the posterior and most superior part of The primary objective of the trial is to investigate if indi- the calcaneus in the midline, which on sagittal vidualized treatment of acute Achilles tendon rupture ultrasound examination is