Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-014-3042-1
The Turkish version of the Achilles tendon Total Rupture Score: cross-cultural adaptation, reliability and validity ¨ nder Kilic¸oglu • Ebru Kaya Mutlu • Derya Celik • O Arzu Razak Ozdincler • Katarina Nilsson-Helander
Received: 9 December 2013 / Accepted: 25 April 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The Achilles tendon Total Rupture Score (ATRS) is a questionnaire designed to evaluate pain, symptoms, function and physical activity after Achilles tendon rupture. The purpose of this study was to translate and culturally adapt the ATRS into Turkish and to determine its reliability and validity. Methods The ATRS was translated into Turkish in accordance with the stages recommended by Beaton. Seventy-four patients (73 male; average age: 42.3 ± 7.6; range 27–63 years) suffering from previous Achilles tendon ruptures were included for the study. The ATRSTurkish was administered twice at 7–14 days intervals with 52 of the 74 patients (51 male, average age: 41.8 ± 7.8) to assess the test–retest reliability. Cronbach’s a was used for internal consistency, and the inter-rater correlation coefficient (ICC) was used to calculate the test–retest reliability. The Turkish Short-Form-12 (SF-12) and the Foot and Ankle Outcome Score (FAOS) were employed for validity estimation.
Results The internal consistency (Cronbach’s a = 0.95) and the test–retest reliability (ICC = 0.98) were excellent. The mean interval between the two tests was 7.1 ± 3.1 days. The mean and standard deviation of the first and second assessment of the ATRS were 78.1 ± 23.1 and 79.1 ± 22.5, respectively. The correlation coefficient between the ATRS-Turkish and the FAOS subscales (pain, symptoms, activities of daily living, sports and recreational activities, and quality of life) were determined (r = 0.82, r = 0.66, r = 0.79, r = 0.83 and r = 0.60, respectively, p \ 0.0001). The ATRS-Turkish displayed good correlation with the SF-12 physical component score (r = 0.63, p \ 0.001) and no correlation with the SF-12 mental component score (r = 0.22, p = 0.06). Conclusion The ATRS-Turkish was found to be reliable and valid for outcome evaluation after Achilles tendon ruptures. Level of evidence II.
Electronic supplementary material The online version of this article (doi:10.1007/s00167-014-3042-1) contains supplementary material, which is available to authorized users.
E. Kaya Mutlu (&) D. Celik A. R. Ozdincler Division of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Istanbul University, 34093 Bakirkoy, Istanbul, Turkey e-mail: [email protected]
¨ . Kilic¸oglu O Department of Orthopaedics and Traumatology, Faculty of Medicine, Istanbul University, Istanbul, Turkey K. Nilsson-Helander Department of Orthopaedics, Kungsbacka Hospital, Kungsbacka, Sweden
Achilles ATRS Score Reliability
The Achilles tendon is the most frequently ruptured tendon, commonly affecting both competitive and recreational athletes as well as sedentary individuals. The Achilles tendon endures strain and risks rupture from running, jumping, and sudden acceleration or deceleration [17, 22]. The incidence of these ruptures has increased during the past few decades; an incidence of 18 per 100,000 has been reported [9, 22, 23, 28]. Achilles tendon rupture causes pain in acute phases and reduces muscle strength, ultimately adversely affecting the functional abilities of these patients [32, 33].
Knee Surg Sports Traumatol Arthrosc
Clinical tests, such as the Thompson test, the calf squeeze test and palpation of the gap test on the tendon body, are useful in the diagnosis of Achilles tendon ruptures; however, these tests cannot predict the disability associated with the condition [2, 7, 19]. Patient-reported outcomes can be used to determine the level of disability resulting from Achilles tendon rupture because they describe the evaluation of the condition and serve as an important parameter for decisions regarding the return to activities and sports [4, 15, 18]. In general, the majority of patient-reported outcomes reflect the language and social culture of the community in which they were established; therefore, it is necessary to translate and culturally adapt these scores for use in other communities. Several subjective and objective scales have been developed to measure Achilles tendon rupture. The Leppilahti  and Merkel  scores were developed to evaluate the prognostic factors of Achilles rupture repair or to compare surgical management outcomes of Achilles tendon ruptures. These include both subjective and objective components and have not been validated in any language. In addition, the psychometric properties of these scores have not been reported. The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale is a clinical rating system developed by Kitaoka et al.  that combines subjective pain and function scores provided by the patient with objective scores based on the surgeon’s physical examination of the patient. The Foot and Ankle Outcome Score (FAOS) is calculated from a patientadministered 42-item questionnaire developed for foot and ankle-related disabilities . Although the AOFAS and FAOS have been used for Achilles tendon rupture [13, 27], these systems were not specifically developed for Achilles tendon pathologies . Developed in 2007, the Achilles tendon Total Rupture Score (ATRS) is a patient-reported measure for outcome assessment of an Achilles tendon rupture . It is a score that consists of 10 items designed to measure patientreported symptoms and their effect on physical activity after an Achilles tendon rupture. This is the only outcome measure in the literature developed specifically for Achilles tendon ruptures [3, 6, 11]. The ATRS has been translated into English and Danish and has been psychometrically tested. Cross-cultural adaptations may contribute to a better understanding of the measurement properties of the ATRS as it is translated into Turkish. It is important to generate the ATRS-Turkish because no outcome measure for the assessment of Achilles tendon rupture exists for Turkishspeaking individuals. The main hypothesis of this study was that it would be possible to translate and culturally adapt the ATRS-Turkish to aid in enhanced understanding for Turkish-speaking individuals. Additionally, we hypothesized that the ATRS-
Turkish would provide adequate internal consistency and test–retest reliability as well as acceptable construct validity compared with the FAOS and Short-Form-12. The purpose of this study was to translate and culturally adapt the ATRS into Turkish and to determine its reliability and validity.
Materials and methods Translation and cultural adaptation The ATRS was translated into Turkish and culturally adapted in accordance with the stages recommended by Beaton . Two Turkish individuals with a good command of Swedish were responsible for the literal and conceptual translation of the ATRS. The informed translator was a physical therapist, and the uninformed translator was tourism professional. Turkish was the native language of both translators; however, they were fluent in Swedish. The translations were independently completed. The language of both translations was compared and reviewed by a bilingual individual, who highlighted any conceptual errors or inconsistencies to provide the first Turkish translation. Subsequently, two native Swedish speakers with a good command of Turkish separately translated the finalized Turkish version back into Swedish. Both translators were unaware of the purpose of the study and had no access to the original score. A committee comprised of four translators and the original author compared the back-translated version of the ATRS with the initial Swedish version. This committee approved the Turkish version and titled it ATRSTurkish. Once approved, the pilot test was conducted with 20 patients who fulfilled the eligibility criteria of the study to determine the comprehensibility of the ATRS-Turkish. When the patients completed the questionnaire, the physical therapists interviewed them. The patients were questioned about their difficulties in understanding the questions immediately after completing the form. The questions that were difficult to understand were noted, and the patients were asked for their recommendations for revising the questions. Subjects and procedures for assessment of reliability and validity The study was conducted as a questionnaire-based crosssectional survey of patients with a previous Achilles tendon rupture. The digital patient database was retrospectively reviewed using ICD-10 coding to identify all of the patients with acute Achilles tendon rupture (ICD-10 code: DS860) admitted to the Istanbul University Faculty of Medicine, Department of Orthopaedics and Traumatology. A total of 109 patients were surgically treated by the same surgeon
Knee Surg Sports Traumatol Arthrosc
between January 2005 and January 2013. Of these, 16 patients could not be reached by phone, and nine patients did not agree to participate in the study. The remaining 84 (77 %) patients were invited to participate in the present study. Patients were initially examined by an orthopaedic surgeon from the Istanbul University Faculty of Medicine, Department of Orthopaedics and Traumatology who performed the end-to-end anastomotic surgery. The eligibility criteria were as follows: (1) age 20–60 years; (2) underwent unilateral Achilles tendon rupture surgery; and (3) able to read and write in Turkish without illiteracy or lack of understanding of Turkish. Patient-reported outcome measures The ATRS is a disease-specific tool designed to evaluate symptoms and physical activity in patients with Achilles tendon rupture. The ATRS contains ten items for which patients are asked to respond using an 11-grade Likert scale by checking a box labelled 0–10. A maximal score of 100 indicates no symptoms and full function, whereas a minimum score of 0 indicates severe symptoms and no function . The FAOS is a 42-item questionnaire originally designed to evaluate patients with ankle ligament injuries . The FAOS includes five separate subscales: pain (9 items); other symptoms, such as stiffness, swelling and range of motion (7 items); activities of daily living (ADL) (17 items); sport and recreational activities (Sport/Rec) (5 items); and lower limb-related quality of life (QoL) (4 items). Each of the subscales is calculated as the sum of the items included. Raw scores are then transformed to a scale ranging from 0 to 100. A higher total value indicates fewer problems and/or functional limitations. The Short-Form-12 (SF-12) was developed based on the 36-item Short-Form (SF-36) with the intent of reproducing the SF-36 in a shorter and more practical form . The SF-12 is comprised of 12 items that measure physical functioning (PF), role physical (RP), role emotional (RE), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF) and mental health (MH). The eight domain scores were aggregated into physical and mental component scores (SF-12 PCS and SF-12 MCS). The SF12 PCS and SF-12 MCS summary scores, which were derived by the weighted sum of 12 items scores using the USA standard SF-12 scoring algorithm, were considered as the primary outcomes of this study . Study procedures Administration of outcome measures Patients were asked to complete the ATRS-Turkish (Appendix of ESM) and the previously validated Turkish
versions of the FAOS and the SF-12 [10, 14]. The three questionnaires were administered to the patients in random order using computer-generated random numbers . The physical therapists distributed the ATRS-Turkish, the FAOS and the SF-12 to the patients in the waiting room after an appointment with the orthopaedic surgeons. The patients were then asked to complete the ATRS-Turkish by e-mail 7–14 days after their first assessment to determine the test–retest reliability. After each patient completed the questionnaire, the physical therapists checked for missing responses. Patients who skipped a question on the questionnaire were asked to provide a reason. Any difficulty in understanding the question or incompatibility with their problem was noted. A total of 74 out of the 84 patients (67.9 %) were eligible for inclusion in the study. Prior to the start of the study, the patients completed an informed consent form, which was approved by the ethical committee at Istanbul University (IRB study protocol:B.30.IST.0.32.71.00/2757). Statistical analysis All statistical analyses were performed with the statistical package for the social sciences (SPSS) 17.5 (SPSS Inc., Chicago, IL, USA). This analysis included frequency counts and percentages for nominal variables, the measures of central tendency (means, medians) and the dispersion [standard deviations (SD), ranges] for continuous variables. The Kolmogorov–Smirnov test was used to assess the distribution. The first and second assessments of the scores were found to be normally distributed. The measurement properties analysed in this study included internal consistency, test–retest reliability, construct validity, and ceiling and floor effects. Reliability Reliability refers to the consistency of measurement and includes internal consistency as well as the test–retest reliability. The homogeneity of the questions within a questionnaire (internal consistency) was assessed using Cronbach’s coefficient a. An a of 0.7 is considered fair, 0.8 is good, and 0.9 represents excellent internal consistency . In this study, the patients included in the first assessment of the ATRS-Turkish were used to assess internal consistency. The test–retest reliability represents a scale’s effectiveness in producing consistent results when administered on different days when an individual’s status has remained stable . The outcome measure was applied and then reapplied after 7–14 days. The results were then compared for agreement using an intra-class correlation coefficient (ICC) to measure the test–retest reliability of the ATRS-
Knee Surg Sports Traumatol Arthrosc
Turkish. Patients who reported ‘‘no change’’ in their condition between the first and second tests were included in the analysis of the test–retest reliability. The ICC was also used to calculate standard error measurement (SEM), an index of measurement precision. The SEM is calculated as the SD of the scores divided by the square root of (1-ICC). The minimal detectable change (MDC) refers to the minimal amount of change within the measurement error. The SEM was used to determine the minimum detectable change at the 95 % limit of confidence (MDC 95 %) and was calculated as the SEM times 1.96 times the square root of 2 . Validity Validity refers to the degree to which a study accurately reflects or assesses the specific concept that the researcher is attempting to measure . In this study, we examined three aspects of validity: construct, convergent/divergent, and content validity. Evidence for construct validity of the ATRS-Turkish was provided by determining its relationship with the Turkish version of the FAOS and the SF-12. The SF-12 PCS was used to assess the convergent validity. Evidence for divergent validity was provided by determining the relationships with the SF-12 MCS. Pearson correlation coefficients and their 95 % confidence intervals were calculated to assess construct and convergent/divergent validity. Correlation values of 0.4 or greater were considered satisfactory (specifically, r C 0.81–1.0 was excellent; 0.61–0.8, very good; 0.41–0.6, good; 0.21–0.4, fair; and 0–0.2, poor) . Distribution and ceiling and floor effects Content validity was evaluated by the distribution and occurrence of ceiling and floor effects. Ceiling and floor effects of the ATRS-Turkish at the first and second tests were assessed by calculating the proportion of the patients with the maximum (100) or minimum (0) scores relative to the total number of patients. Descriptive statistics (mean values, standard deviations, and quartiles) were calculated to determine distribution and ceiling/floor effects, which were considered to be relevant if experienced by [30 % of the subjects .
Results Translation process and testing Based on the translators’ comments, the questions were clear, concise and easy to translate because the words of the Swedish language corresponded one to one with
Table 1 Demographics of study groups Variable
51 (98.1 %)
73 (98.6 %)
1 (1.9 %)
1 (1.4 %)
41.8 ± 7.8
42.3 ± 7.6
Primary school (%)
4 (7.7 %)
6 (8.1 %)
High school (%)
4 (7.7 %)
5 (6.8 %)
University degree (%)
38 (73.1 %)
54 (73 %)
Master and doctorate degree (%)
6 (11.5 %)
9 (12.2 %)
Age (years) Mean ± SD Range Education
Involved side Right knee
27 (51.9 %)
35 (43.3 %)
25 (48.1 %)
39 (52.7 %)
Table 2 The mean value, standard deviation, median value, minimum and maximum value, standard error and confidence interval of the outcomes Outcomes
Mean ± SD
ATRS administration 1
78.1 ± 23.1
ATRS administration 2
79.1 ± 22.5
FAOS pain FAOS symptoms FAOS ADL
(95 % CI)
92.1 ± 12.2
89.3 ± 15.7
93.8 ± 11.4
78.6 ± 24.8
65.5 ± 27.3
49.1 ± 8.4
51.1 ± 1.2
ATRS Achilles tendon Total Rupture Score, FAOS Functional Ankle Outcome Score, ADL activities of daily living, sport/rec sport and recreational activities, QoL quality of life, SF-12 Short-Form Health Survey-12, PCS physical component scale, MCS mental component scale
Turkish words; therefore, the translation did not require any changes. Additionally, the pilot test did not demonstrate any difficulty in patients’ understanding of these questions. The patients required approximately 3–5 min to complete the ATRS-Turkish. A total of 74 patients completed all questionnaires in the first assessment, and 52 of them completed the second assessment for the test–retest reliability. Patients were evaluated after an average of 42.3 ± 27.8 months (range 12–120 months) post-surgery.
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The majority of Achilles ruptures occurred during sports, in particular football and the other ball sports. Table 1 illustrates the demographic and clinical characteristics of these patients. Means and standard deviations for each of the scores on the first and second tests of the ATRS-Turkish are provided in Table 2. Reliability The internal consistency of the first assessment of the ATRS-Turkish was excellent with a Cronbach’s a of 0.95. Mean values of the first and second assessment of the ATRS-Turkish and the first assessment of the Turkish version of the FAOS was presented in Table 2. The mean interval between the two assessments was 7.1 ± 3.1 days. The test–retest reliability of the ATRS-Turkish was found to be excellent (ICC = 0.98). The SEM and MDC for the ATRS-Turkish were 3.2 and 8.9, respectively. Validity The correlation coefficient between the ATRS-Turkish and the FAOS sub-scales (pain, symptoms, ADL, sport/rec, QoL) were reported as good to excellent (r = 0.82, r = 0.66, r = 0.79, r = 0.83, r = 0.6, respectively; p \ 0.0001). The ATRS-Turkish and the SF-12 PCS displayed good correlation (r = 0.63, p \ 0.001). No correlation between the ATRS-Turkish and the SF-12 MCS was observed (r = 0.22, p = 0.06). Distribution and ceiling/floor effects Ceiling and floor effects and the number of items answered were identical during the test and re-test assessments. None of the patients in the overall ATRS achieved the minimum score, implying the absence of floor effects. In the first assessment, 14 % of the patients reached the maximum score compared with 22 % of the patients in the second assessment. However, this percentage is still below the cut point of 30 %, suggesting no ceiling effect.
Discussion The most important finding of the present study was that ATRS-Turkish displays good measurement properties, high reliability, and appropriate construct validity and that the ATRS-Turkish can be used in the Turkish population to evaluate Achilles tendon rupture. The original version of the ATRS was successfully translated and adapted to the Turkish language. High internal consistency was demonstrated by Cronbach’s a, similar to previously reported data [6, 11, 24]. The high test–retest
reliability was demonstrated by an ICC value of 0.98, which was within the range of the ICC values (0.96–0.98) in the original version . The time interval between repeat measurements is an important factor for determining the test– retest reliability . In the literature, the reported intervals for the estimation of the test–retest reliability of the ATRS range from 15 min to 21 days [3, 6]. The ATRS contains a small number of questions, which carries the risk of patients becoming familiar with or memorizing the questions. Therefore, 7–14 days was chosen for the retest assessment to decrease the possibility of remembering the questions. In addition, we believe that the patients’ conditions were not expected to change over this time period. The MDC was found to be 8.9; when a patient is measured two or more times with the ATRS-Turkish, a change of\8.9 from one measurement to the next should be considered as a reflection of measurement error rather than a true change in the patient’s condition. MDC values are higher for the ATRS-Turkish compared with the English version (MDC = 6.75) but lower than the Danish version (MDC = 18.5). In recent studies, evidence for ATRS validity has been investigated by determining its relationship with many other patient-reported outcomes, including the FAOS, the VISA-A, the Disability Rating Index, the SF-36 and the EQ-5D [6, 11, 24]. Nilsson et al.  reported good to excellent correlations between the Swedish version of the ATRS and the FAOS subscales (r = 0.6 to r = 0.84) and the VISA-A (r = 0.78). In this study, evidence for construct validity was obtained by determining the relationship between the ATRS-Turkish and the Turkish version of the FAOS as well as the SF-12. The correlation coefficient between the ATRS-Turkish and the Turkish version of the FAOS subscales were similar to the Swedish version of the ATRS (r = 0.6 to r = 0.83). The correlation between the SF-36 and scores of specific instruments are typically not very strong. This confirms that the SF-36 measures additional aspects of physical health and provides more comprehensive, but less specific, information about a patient’s overall health than condition-specific questionnaires . As expected, the ATRS was more strongly related to concurrent measures of physical function than to concurrent measures of mental function. In this study, the ATRSTurkish and the SF-12 PCS showed good correlation (r = 0.63), but this correlation value was lower than the Danish version (r = 0.71). Similar to the Danish version of the ATRS, no correlation was found between the ATRSTurkish and the SF-12 MCS (r = 0.22). In the assessment of ceiling and floor effects, it was found that the number of participants who scored the maximum and minimum values on the questionnaire was well below the 30 % threshold. This suggests that the ATRS-Turkish is an appropriate tool for individuals with an Achilles tendon rupture.
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The major limitation of this study is that responsiveness to the ATRS-Turkish was not assessed, which is critical to evaluate a patient’s change in status. While the presented translation has been validated with this preliminary study, the Turkish form should be tested in larger and more diverse populations. Future studies are necessary to assess responsiveness and to determine the minimum clinically important differences for the ATRS-Turkish.
Conclusion Based on the results obtained in the assessments of the measurement properties, the ATRS-Turkish version was reliable and valid and can be used in clinical practice. Conflict of interest
The authors declare no conflict of interest.
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