One of the most widely used PRO tools for foot and ankle conditions is the American Orthopedic Foot and Ankle Society Score (AOFAS).

Developed in 1994, the clinician-based AOFAS covers four different regions of the foot: The ankle-hindfoot, midfoot, metatarsophalangeal (MTP)-interphalangeal (IP) for the hallux, and MTP-IP for the lesser toes.

These four anatomic regions have their own version of the AOFAS survey. Each tool is designed to be used independent of the others. However, each tool is comprised of nine questions and cover three categories:: Pain (40 points), function (50 points) and alignment (10 points). These are all scored together for a total of 100 points.

The surveys include a mixture of questions that are both subjective and objective in nature. The pain category which asks patients a single question about their level of pain is subjective, while the alignment category (to be answered by the physician) is objective. The function category, however, consists of 5-7 questions and requires completion by both the patient and the physician. Unlike other outcome tools which fall into a single category, AOFAS is a clinician reporting tool that requires both patient and provider participation to be fully complete.

The AOFAS is not a patient-reported outcome tool (PRO tool) and when created, it was designed for physicians to help standardize the assessments of patients with foot or ankle disorders. Since its inception, however, it has gained widespread popularity. Unfortunately, some concerns have been raised with regards to its validity and reliability.

In 2006, SooHoo et al. found that AOFAS scores correlated poorly with the extensively studied and validated Medical Outcomes Shortform-36 (SF-36) [1] and they called into question how robust the AOFAS tool really was. At the same time, more recent studies have contradicted this assertion and found that some level of correlation between both scoring systems does exist –particularly in specific cases such as the evaluation of an Achilles Ruptures following treatment by Percutaneous Technique [2].

To bridge this gap, although the AOFAS questionnaire has yet to be validated, and no direct correlations have ever been firmly established between itself and other outcome tools, many clinicians continue to administer the AOFAS survey to patients simultaneously with other reporting surveys [3].

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We’ve evaluated the strengths and weaknesses for all the most popular Foot & Ankle PRO measures.

Strengths

The four AOFAS scales continue to be some of the most widely-used instruments in clinical studies, and they remain in use at a substantially higher rate than other scales that have been validated [4]. Both the ankle and hindfoot tools are easy to apply and understand and because of its wide use in the literature, AOFAS score values still offer the best comparison between different studies.

 

Weaknesses

AOFAS is not a PRO tool but is instead clinician-reported. Although it is a highly rated outcome instrument, more physicians are turning towards the use of PRO tools to assist them in evaluating patient outcomes. It’s also becoming increasingly evident that clinician-reported surveys are unlikely to fully reflect how a patient feels or functions, and are also limited by their insight, reproducibility and lack of consistency. Additionally, the use of PROs in clinical practice has been found to improve patient-clinician communication and can affect care and outcomes [6].

One weakness of the AOFAS scales is that they are still not validated instruments.  Additionally, there has been some concern that the interpretation of scoring is not straightforward and that in order to fully interpret the values received by a patient using an AOFAS instrument, either normative data or a large sample of similar disease data is at times needed for reference [3]. To help address this, various authors established arbitrary subgroups of scores to define what ‘excellent’, ‘good’ and ‘fair’ outcomes may correlate to. For instance, some authors have stated that scores between 90 and 100 points represent an ‘excellent’ result while 80 to 90 points is indicative of a ‘good’ result [3]. At the same time however the value of an ‘acceptable’ result is still widely disputed and tends to vary significantly depending on the literature that one reviews [3].

Lastly, there is no consensus on what magnitude of change on the AOFAS score represents a significant clinical change and improvement in the patient’s function [3].

These two issues highlight one of the main critiques of AOFAS clinician-reported tool –its subjectivity and the increased likelihood that the interpretation of patient scores and the perception of patient improvement may at times vary greatly amongst physicians and researchers.

Despite this, the AOFAS clinician-reporting tool continues to be the consensus survey instrument amongst a wide range of healthcare providers that is used for measuring outcomes with regards to ankle and foot pathology.

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References

  1. SooHoo, N. F., Vyas, R., & Samini, D. (2006). Responsiveness of the foot function index, AOFAS clinical rating systems, and SF-36 after foot and ankle surgery. Foot & ankle international, 27(11), 930-934.
  2. Ceccarelli, F., Calderazzi, F., & Pedrazzi, G. (2014). Is there a relation between AOFAS ankle-hindfoot score and SF-36 in evaluation of Achilles ruptures treated by percutaneous technique?. The Journal of Foot and Ankle Surgery, 53(1), 16-21.
    <https://www.researchgate.net/publication/258635015_Is_There_a_Relation_between_AOFAS_Ankle-Hindfoot_Score_and_SF-36_in_Evaluation_of_Achilles_Ruptures_Treated_by_Percutaneous_Technique>
  3. Ceccarelli, F., Calderazzi, F., & Pedrazzi, G. (2014). Is there a relation between AOFAS ankle-hindfoot score and SF-36 in evaluation of Achilles ruptures treated by percutaneous technique?. The Journal of Foot and Ankle Surgery, 53(1), 16-21.
    <https://www.researchgate.net/publication/258635015_Is_There_a_Relation_between_AOFAS_Ankle-Hindfoot_Score_and_SF-36_in_Evaluation_of_Achilles_Ruptures_Treated_by_Percutaneous_Technique>
  4. Pena, F., Agel, J., & Coetzee, J. C. (2007). Comparison of the MFA to the AOFAS outcome tool in a population undergoing total ankle replacement. Foot & ankle international, 28(7), 788-793.
    <http://fai.sagepub.com/content/28/7/788.short>
  5. Hunt, K. J., & Hurwit, D. (2013). Use of patient-reported outcome measures in foot and ankle research. J Bone Joint Surg Am, 95(16), e118.
  6. Cook, J. J., Cook, E. A., Rosenblum, B. I., Landsman, A. S., & Roukis, T. S. (2011). Validation of the American College of Foot and Ankle Surgeons scoring scales. The Journal of Foot and Ankle Surgery, 50(4), 420-429.
    <file:///home/chronos/u-f114defcc026d45948bac8278f5e12eb13a52029/Downloads/Random/Validation_ACFASscoringscale2011.pdf>
  7. When Using Patient-Reported Outcomes in Clinical Practice, the Measure Matters: A Randomized Controlled Trial
    <http://jop.ascopubs.org/content/10/5/e299.full>