A new foot and ankle outcome score: Questionnaire based, subjective, Visual-Analogue-Scale, validated and computerized

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Abstract

Our purpose was to construct and validate a new score taking into consideration the flaws of existing scores.

Methods

A new score named Visual-Analogue-Scale Foot and Ankle (VAS FA) with the following features was constructed: questionnaire based on 20 subjective questions, Visual-Analogue-Scale (VAS) based rating, computerized evaluation. The score was validated in 121 subjects. For validation, SF-36® and Hannover Questionnaire (Q) were obtained and correlated with VAS FA.

Results

The correlation VAS FA versus SF-36® and Q (Pearson, all p-values <0.001, r  0.5) was sufficient for the total score and all score categories (pain, function, other complaints).

The time needed for evaluating the scores was significantly lower for VAS FA than for SF-36® and Q (Oneway-ANOVA, p < 0.001).

Conclusions

The introduced score is the first validated (on SF-36®), subjective, VAS based outcome score for foot and ankle. The VAS FA is computerized which enables faster evaluation than SF-36® or Q.

Introduction

Outcome assessment has become critical in evaluating the efficiency of both surgical procedures and medical treatments [1], [2], [3]. A wide variety of outcome measures have been proposed for use in conditions affecting the foot and ankle. A validated score for foot and ankle outcome is unavailable [1], [4]. This deficiency was recently established at the American Orthopaedic Foot and Ankle Society's (AOFAS) 2003 and 2005 Annual Summer Meetings [1], [2], [3]. Furthermore, the insufficiency of supposedly objective assessment was clearly stated [1]. Our purpose was to construct and validate a new score taking into consideration the flaws of existing scores.

There are two possibilities for validation:

  • (1)

    A score is validated for a specific population and language [5], [6]. This requires an enormous case number, as for example more than 3000 subjects for the validation of the German SF-36® version [5]. Worldwide, this type of validation was achieved only for the SF-36® [5], [6]. No foot and ankle score (including the AOFAS score) has ever been validated in that fashion.

  • (2)

    A score is validated by sufficient correlation with a validated score [7]. Since the SF-36® is the only validated score, this kind of validation is appropriate only by validation with that score [7]. Many scores for different types of diseases and populations have been validated following this principle [7], [8], [9], [10], [11], [12], [13], [14], [15], [16]. Thus, no foot and ankle score (including the AOFAS score) has passed through this process as far as we know.

We choose the second type of validation process for this newly introduced score.

Section snippets

Validation process

Three scores (SF-36®, Hannover Questionnaire (Q) and Visual-Analogue-Scale Foot and Ankle (VAS FA)) were obtained from a group of voluntary subjects. The results were analyzed and correlated to the scores. The time spent for evaluating the different scores was recorded and compared.

Subjects

One hundred and twenty-one subjects were included in the study. The number of subjects was determined by a statistician after a review of the study design and before starting the study. Fifty-eight of the subjects

Score results and correlation

All questions were answered by all subjects.

Table 1 indicates the score results. Table 2 shows the results of the statistical correlation of the three scores. All correlations were significant regarding the defined p < 0.05 level. Sufficient correlation (r > 0.5) was found in all score categories and total scores.

The SF-36® scores did not significantly differ from the actual normative data (age and gender related) of the average German population (data not shown) [18].

Time spent

The time needed evaluating the

Discussion

The gold-standard score for foot and ankle is regarded as the AOFAS score [4], [19], [20], [21]. This score is widely used as shown by the high number of hits when entering the term “aofas score” into the PubMed®-search engine in the World-Wide-Web (National Library of Medicine). However, this score is problematic due to significant flaws as follows. The score is not validated [1], [4], it cannot be obtained if answers are missing, and contains problematic pseudo-objective assessment. To assess

Acknowledgements

The authors thank Ludwig Hoy, Ph.D. (Institute for Biometry, Hannover Medical School, Hannover, Germany) for his help and support in carrying out the extensive statistical analysis and for his unbiased prior evaluation, Hans Werner Kuensebeck, M.D. (Department of Psychosomatics and Psychotherapy, Hannover Medical School, Hannover, Germany) for his assistance during the SF-36® evaluation, and Justin Bender, Ph.D. for his assistance in translating the Visual-Analogue-Scale Foot and Ankle (VAS FA)

References (36)

  • Impact of Comorbidities on the Measurement of Ankle Health. American Orthopaedic Foot and Ankle Society (AOFAS), 21st...
  • N.F. SooHoo et al.

    Evaluation of the validity of the AOFAS Clinical Rating Systems by correlation to the SF-36

    Foot Ankle Int

    (2003)
  • M. Bullinger et al.

    SF-36 Fragebogen zum Gesundheitszustand

    (1998)
  • J.E. Ware et al.

    The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection

    Med Care

    (1992)
  • E.K. Tan et al.

    Validation of a short disease specific quality of life scale for hemifacial spasm: correlation with SF-36

    J Neurol Neurosurg Psychiatry

    (2005)
  • D. Cella et al.

    Validation of the Functional Assessment of Chronic Illness Therapy Fatigue Scale relative to other instrumentation in patients with rheumatoid arthritis

    J Rheumatol

    (2005)
  • R.L. Carrau et al.

    Validation of a quality-of-life instrument for laryngopharyngeal reflux

    Arch Otolaryngol Head Neck Surg

    (2005)
  • F. Angst et al.

    Comprehensive assessment of clinical outcome and quality of life after resection interposition arthroplasty of the thumb saddle joint

    Arthritis Rheum

    (2005)
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