The study was approved by the local ethics committee.
According to the "guidelines for the process of cross-cultural adaptation of self-report measures" the VISA-A score was cross-culturally adapted into German (VISA-A-G) in six steps [17 (
link)].
Step I: Initial translation from English to German (forward translation) was performed by three independent translators with German mother tongue. An orthopaedic surgeon specialised in foot, ankle, and Achilles tendon, and a sport scientist both were aware of the concepts being examined in the questionnaire. A third translator without medical background ("naïve translator") was not familiar with the questionnaire's concepts. Written reports were made to indicate rationales for decision making, linguistic difficulties and problems with regards to content.
Step II: Considering the original VISA-A the resulting three German versions were synthesized during a consensus meeting of the three translators. A written report documented the procedure.
Step III: Back translation of the preliminarily VISA-A-G questionnaire was then conducted by two American English native speakers fluid in German but without medical background and blind to the original VISA-A.
Step IV: An expert committee was constituted including forward and back translators, a health professional, and a language professional. This panel developed the prefinal VISA-A-G version by consensus discussion with respect to semantic, idiomatic, experiential, and conceptual equivalence based on all previous material (original, target and back translated questionnaires including the respective reports).
Step V (pretesting): The prefinal questionnaire was filled out by a cohort of 35 male and 42 female persons (asymptomatic persons). These persons were then asked regarding their individual understanding of the questionnaire's items. The interviewer prepared a report on the test subjects, understanding of the items, and their decision making. Again the questionnaire was adapted respectively resulting in a final version.
Step VI: The final version of the VISA-A-G questionnaire and all reports and forms were then subjected to a review done by the developers of the VISA-A-G questionnaire for appraisal of the adaptation process.
The final VISA-A-G questionnaire was then subjected to psychometric testing including an analysis of reliability and validity in 30 Achilles tendinopathy patients and 79 asymptomatic people. Internal consistency was evaluated in 30 Achilles tendinopathy patients.
This was done following closely the procedure described in the original VISA-A report [8 (
link)].
Test subjects: For reliability and validity testing four groups of test subjects were defined according to the status of their Achilles tendon. Group I included 15 preoperative Achilles tendinopathy patients selected prospectively from the own center. Group II consisted of 15 Achilles tendinopathy patients conservatively treated. These patients were recruited from review of the most recent charts in our sports medicine center. 48 Frankfurt/Main university pharmacology students (one class preparing for their examinations) without Achilles tendon complaints constituted group III. Group IV was formed by 31 members of three local running clubs serving as non injured but active controls. That population was recruited by direct contact during their practise.
Inclusion criteria for all four groups were: age over 18 years, willingness to take part in this project, and ability to give written informed consent. Contrasting to the original VISA-A publication [8 (
link)] only patients suffering from unilateral Achilles tendinopathy were included (group I and II). Achilles tendinopathy was defined as tenderness of the midportion of the Achilles tendon 2 to 7 cm proximal to the Achilles tendon insertion and a history of load induced pain in this area [2 (
link)-4 (
link)]. This clinical diagnosis includes degenerative Achilles tendon lesions, Achilles tendon partial tears on a microscopic level, and paratendinosis or combinations of these. For the control groups (group III and VI) subjects with previous Achilles tendon injuries were included, if they did not complain any actual symptoms or functional deficiencies. Persons with inadequate compliance and pregnant or nursing women were excluded from participating in any of the four groups. Patients (group I and II) with bilateral symptoms, subtotal or complete Achilles tendon tears, insertional Achilles tendinopathy, Haglund's disease, and relevant injuries or previous surgery of the lower extremity, radicular and pseudoradicular induced pain were excluded.
To document the individual level of activity the ankle activity score which is a reliable, valid, and sensitive measure [18 (
link)] was calculated for all test subjects.
For concurrent validity testing all participants (n = 109) completed the VISA-A-G questionnaire and Achilles tendinopathy severity was additionally rated by an orthopaedic surgeon specialized in Achilles tendon disorders (HL) using a generic tendon grading system [19 (
link)] and a "classification system for the effect of pain on athletic performance" [20 ]. Even if the clinimetric properties of these tools are not formally validated so far they have been used as a standard for concurrent validity testing in previous VISA-A validation research [8 (
link),9 (
link),12 (
link)]. Percy and Conochie categorized pain and function following surgery of Achilles tendon tears: "Excellent" means full function and no residual disability. "Good" is defined as full function with no real limitation of activities and minor pain. A "fair" result is represented by some limitation of activities. Severe weakness and marked limping indicates a "poor" result [19 (
link)]. Curwin and Stanish assessed six degrees of reported exercise induced tendon pain and the level of sports performance: 1 = no pain and unrestricted level of sports performance; 2 = pain only with extreme exertion and unrestricted level of sports performance; 3 = pain with extreme exertion and 1 to 2 hours afterward and normal or slightly decreased level of sports performance; 4 = pain during and after any vigorous activities and somewhat decreased level of sports performance; 5 = pain during activity forcing termination and markedly decreased level of sports performance; 6 = pain during daily activities and unable to perform sport [20 ].
Besides this, VISA-A-G results for patients expected to present moderate symptoms (group II) and patients probably suffering the most severe symptoms (group I) were compared with the controls (group III and IV).
Next, the VISA-A-G ratings from this study were compared with the respective VISA-A group values presented in the original publication [8 (
link)].
For reliability testing a subset of subjects were included. For test retest reliability all conservative patients (n = 15), all students (n = 48), and all joggers (n = 31) were evaluated by the VISA-A-G questionnaire two times within one week. Intertester reliability was assessed by comparing the results when both authors administered the VISA-A-G questionnaire independently in a one to seven days interval to five participants from the students and conservative Achilles tendinopathy group respectively.
Lohrer H, & Nauck T. (2009). Cross-cultural adaptation and validation of the VISA-A questionnaire for German-speaking Achilles tendinopathy patients. BMC Musculoskeletal Disorders, 10, 134.