Victorian Institute of Sports Assessment – Achilles questionnaire, German version

Authors

Purpose

The primary objective of the VISA-A-G is to provide a culturally and linguistically validated tool for assessing the severity of Achilles tendinopathy in German-speaking populations. Prior to its development, researchers and clinicians in Germany lacked a standardized, disease-specific questionnaire, which hindered the ability to conduct high-quality, internationally comparable research. By translating and validating this gold-standard instrument, the authors addressed a significant methodological gap in European sports medicine and orthopedic research.

For clinicians, the VISA-A-G serves as a vital tracking mechanism to monitor patient recovery trajectories over time, offering quantifiable data to justify the continuation or modification of treatment plans. For researchers, it enables the inclusion of German-speaking cohorts in global studies evaluating novel interventions, such as eccentric loading protocols or shock-wave therapy. Ultimately, the scale ensures that the subjective impact of tendon pathology is measured with the same rigor and consistency across different languages and cultures.

Construct

The psychological and physical construct measured by the VISA-A-G is the clinical severity and functional burden of Achilles tendinopathy. This construct is conceptualized as a multidimensional experience encompassing three primary domains: localized pain, functional capacity in daily life, and the ability to engage in sports or physical activities. Rather than treating pain as an isolated symptom, the scale evaluates how pain mechanically limits movement and alters behavioral patterns, providing a comprehensive picture of the patient's overall impairment.

The theoretical framework of the instrument posits that tendon health exists on a continuum, ranging from severe, debilitating pathology to complete, asymptomatic function. The pain domain captures the intensity and frequency of discomfort, while the function domain assesses the patient's ability to perform routine weight-bearing tasks. The activity domain, which carries the heaviest scoring weight, evaluates the threshold at which symptoms interfere with athletic performance. Together, these dimensions interact to form a holistic index of tendon health, reflecting both the physiological state of the tissue and the psychological readiness of the patient to load the tendon.

Validity

The validation process for the VISA-A-G demonstrated robust evidence of both concurrent and known-groups validity. To establish concurrent validity, the researchers compared the questionnaire scores against two established, generic clinical grading systems: the Percy and Conochie tendon classification and the Curwin and Stanish athletic performance classification. The results yielded exceptionally strong correlations, with a Spearman's rho of 0.95 and -0.95, respectively. These near-perfect correlations indicate that the self-reported VISA-A-G aligns closely with expert clinical evaluations of tendon severity and functional limitation.

Furthermore, the instrument exhibited excellent known-groups validity by successfully discriminating between distinct clinical populations. The scale easily differentiated individuals with symptomatic Achilles tendinopathy (both preoperative and conservatively managed) from healthy, asymptomatic controls, including active runners and university students. The significant score disparities between these groups confirm that the translated scale is highly sensitive to the presence of pathology and accurately reflects the functional deficits associated with the condition.

Convergent & Discriminant Validation Correlations

Reliability

Reliability testing of the VISA-A-G focused heavily on temporal stability and inter-rater consistency, both of which are critical for an instrument intended to monitor treatment progress over time. Test-retest reliability was evaluated by administering the questionnaire twice within a one-week interval to subsets of the study population. The resulting Intra-Class Correlation Coefficients (ICC) for the total score ranged from 0.60 to 0.97, indicating moderate to excellent stability across different patient and control groups.

Inter-rater reliability was also exceptionally high, with an ICC of 0.99 and a Pearson correlation of 0.97 when different administrators delivered the questionnaire. Interestingly, while most individual items showed strong reliability, one specific item related to functional movement (item 6) demonstrated a lower ICC of 0.44. This highlights a common psychometric phenomenon where highly specific functional questions may be subject to greater day-to-day variability or subjective interpretation by the patient, though it did not compromise the reliability of the overall composite score.

Factor Analysis

The provided literature on the VISA-A-G adaptation primarily focuses on translation fidelity, concurrent validity, and reliability, rather than exploring the latent factor structure through Exploratory Factor Analysis (EFA) or Confirmatory Factor Analysis (CFA). In Cross-cultural adaptation studies of previously established instruments, researchers often prioritize demonstrating that the translated items behave similarly to the original version in terms of clinical differentiation, rather than re-evaluating the underlying dimensionality.

However, from a psychometric perspective, the VISA-A is theoretically structured around three distinct but highly correlated dimensions: pain, function, and activity. Future psychometric evaluations of the German version would benefit from structural equation modeling to confirm whether these three theoretical domains load onto a single higher-order factor of 'tendinopathy severity,' or if they function better as independent subscales. Establishing measurement invariance across languages via CFA would further solidify the scale's utility in multinational clinical trials.

Subscales

Instrument

Scoring & Interpretation Guidelines

Victorian Institute of Sports Assessment – Achilles questionnaire, German version Items

Sample

The validation sample consisted of 109 participants divided into four distinct groups: 15 preoperative patients with unilateral Achilles tendinopathy, 15 conservatively treated patients with unilateral symptoms, 48 asymptomatic university pharmacology students, and 31 asymptomatic active runners recruited from local clubs.