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Abstract
Background Currently, there is no consensus regarding the optimal management for patients following an Achilles tendon rupture. To allow comparisons between different treatments, a universally accepted outcome measure is required. However, there are currently a range of these reported within the literature.
Objective To recommend the most suitable patient-reported outcome measure for the assessment of patients following an Achilles tendon rupture, based on a systematic review of first what is currently used and second evidence of validity.
Methods The electronic databases MEDLINE, EMBASE and AMED were searched up to September 2010. Predefined inclusion and exclusion criteria were applied to identify what outcome measures are reported in the literature. Aspects of validity were defined and a checklist used to determine which aspects have been evaluated.
Results Twenty-one outcome measures in 50 research papers were identified. The most commonly used was the American Orthopaedic Foot and Ankle Society hind-foot score. Of the 21 outcome measures, only 4 cited independent validation data. Of these four, only the ‘Achilles tendon Total Rupture Score’ reported evidence to support multiple facets of validity, as defined by a predetermined criteria checklist.
Conclusions The Achilles tendon Total Rupture Score was identified as the only outcome measure which has demonstrated multiple facets of validity for use in this patient group. However, even this tool has limitations. Researchers should be aware of the limitations of the available outcome measurement tools and check on their validity before use in clinical research.
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Introduction
To determine the benefits of a new intervention, clinicians and researchers have traditionally focused on clinician-generated measures. Such measures for patients following a rupture of their Achilles tendon have included muscle strength, calf circumference and range of movement.1 However, over the past two decades, it has become increasingly recognised that the benefits of an intervention from the patients' perspective are also important. This recognition is demonstrated through the explosion of literature reporting ‘new’ patient-reported outcome measures.2
To evaluate patient outcomes following a rupture of the Achilles tendon, a range of multi-item scores have been published.3 More specifically, in 1994, the American Orthopaedic Foot and Ankle Society (AOFAS) published their development of a rating system for ankle hind-foot pathologies.4 It was proposed that this would provide a universal measure for clinicians and researchers. This concept of one universally accepted outcome measure is imperative to allow comparisons across practice. This is of the upmost importance given the debates that still surround the management of this common injury. However, it is equally important that the universally accepted outcome measure has explicitly been developed and evaluated across the many facets of validity.5 ,6
Considering the rationale for the development of the AOFAS ankle hind-foot score and the importance of validity, this systematic review will address two questions. First, what are the most frequently used multi-item patient outcomes, in studies reporting management of rupture of the Achilles tendon? Second, does the literature provide evidence to support the methodological development and subsequent validity of the identified outcome measures, as defined by a predefined checklist? Answering these questions will enable recommendations to be made to clinicians and researchers regarding what patient-reported outcome measures should be used to assess patients following a rupture of their Achilles tendon.
Methods
To address the first question, a systematic review of the electronic databases of MEDLINE, AMED and EMBASE using the Ovid search engine (all until September 2010) was used. The specific search terms, how they were combined and the individual citations yielded for each database can be found in table 1, no prior protocol was published. Combining the search databases resulted in 414 articles.
Search terms and results for each database
Two independent reviewers (RK and CP) independently applied predefined inclusion and exclusion criteria to the 414 articles (figure 1). All interventional study designs, in any language, that reported an isolated acute rupture of the Achilles tendon in subjects over 18 years of age were included. Additionally, all articles had to include the use of a multi-item health outcome measure. Articles reporting subjects presenting with delayed presentation (over 14 days), re-rupture or previous Achilles tendon surgery were excluded. As were articles that included the use of single-item outcomes such as strength, re-rupture or patient satisfaction, or multi-item scoring systems containing no patient-reported items.
Selection of publications for the systematic review.
Results
After reviewing titles and abstracts of the articles, 327 were excluded: 47 of these were not an interventional study design; 154 were not reporting acute Achilles tendon rupture management; 4 did not report on adults (over 18 years); 35 did not report a multi-item patient-derived outcomes and 87 did not report any patient-derived outcome measures.
Subsequently, 87 full-text articles were ordered, of which 37 were excluded:9 were not interventional study designs; 15 did not report a multi-item patient-derived outcome; 2 were unobtainable from the British Library; and 11 did not report any patient-derived outcome measures. Consequently, 50 articles containing 21 different multi-item patient outcomes were included to address the first research question. A summary of the multi-item outcome measures reported in the literature can be found in table 2.
Summary of the Reported outcome measures
To address the second research question, only disease-specific or region-specific multi-item patient outcomes which cited independent validation data were assessed. This resulted in four outcome measures being evaluated in this second stage of the review. These outcome measures were the AOFAS, Olerud and Molander Ankle Score (OMAS), Leppilahti score and the Achilles tendon Total Rupture Score (ATRS).3 ,4 ,7 ,8
The reference list of the articles citing these four outcome measures was checked for references pertaining to their development and/or validation. Additionally, a second search strategy, using MEDLINE, AMED and EMBASE, searched via Ovid (all until November 2010) was undertaken. The individual search terms used were based on the predefined validity checklist, proposed by Terwee et al5 The specific search terms, how they were combined and the individual citations yielded for each outcome can be found in table 3.
Search terms and results for each database
Combining the search databases resulted in no articles for the Leppilahti and ATRS questionnaires. Three citations resulted for AOFAS and one resulted for the OMAS. However, these articles were all excluded for not addressing the aspects of validity of the scores. Each score had one additional article added from the reference lists of the citing articles, which related to the development of the outcome in each case.
The included articles were then evaluated according to a predefined validity checklist proposed by Terwee et al.5 These criteria briefly include the evaluation of content validity, internal consistency, criterion validity, construct validity, agreement, reliability, responsiveness, floor/ceiling effects and interpretability and are summarised in table 4.
Validity checklist results for each outcome measure
Twenty-one multi-item outcome measures were identified from the first search strategy. Of these, 4 were measures of global health, 2 were region-specific and 15 were disease-specific measures. The AOFAS was the most frequently reported multi-item outcome measure in studies reporting rupture management of the Achilles tendon. This score was reported in 38% of the literature.
Of the 17 region-specific and disease-specific outcome measures, only 4 were presented in articles that referenced development and/or validation of that outcome measure. Of these 4 outcome measures, only the ATRS was developed using recognised methodology for outcome measure development. The remaining 3 outcomes were developed using an expert opinion alone.
Discussion
A universal, validated outcome measure is imperative to allow comparisons across practice. Therefore, the aim was to provide clinicians and researchers with evidence-based recommendations regarding what patient-reported outcome measures should be used to assess patients following a rupture of their Achilles tendon. This would be achieved through first reviewing what the most frequently used outcome scores are for patients following a rupture of the Achilles tendon and second if there is an evidence to support their use.
This review has demonstrated that the AOFAS hind-foot score is the most widely reported outcome measure for evaluating Achilles tendon rupture management. However, although this is the most widely used patient-reported outcome measure, there was no evidence supporting the many facets of validity in this patient population.
The OMAS and Leppilahti score also lacked a methodologically robust approach in their development, as the scores were based on an expert opinion alone, with no subsequent articles evaluating the aspects of their validity. In contrast to these outcome measures, the authors of the ATRS did report an appropriate method of development and some subsequent data pertaining to many important aspects of validity. However, because the ATRS is a newly reported outcome measure, it has no data to support the aspects of validity outside of the initial development centre.
This review of the literature has highlighted that the most commonly reported outcome measures are not necessarily the most appropriate for clinicians and researchers to be using. For Achilles tendon rupture management, the ATRS outcome measure is the only patient-reported outcome measure that has been developed and evaluated using appropriate methodologies, as opposed to an expert opinion alone. Consequently, despite the limitations of the ATRS, it is currently the only evidence-based outcome measure for use in Achilles tendon rupture management.
It is clear that further research of the ATRS is required. However, it must also be acknowledged that this in itself will require ongoing research in different contexts, combining a range of methodologies. These should encompass quantitative and qualitative methods to ensure that the score is developed to be reflective of what is important to patients and further explore the weighting that investigators give to the change in individual and overall scores, and determine if the most appropriate scoring methods are being implemented.
Conclusion
It is important for the development of clinical practice and research that practical and appropriate patient-reported outcome measures are universally accepted. This will allow comparisons and meta-analysis of high-quality randomised controlled trials possible into this ever-increasing injury. At present, the best available evidence suggests that the ATRS is the most appropriate outcome measure for evaluating the management of acute Achilles tendon ruptures.
Acknowledgments
The authors would like to acknowledge the financial support from Arthritis Research UK, awarded to Rebecca Kearney as part of an individual fellowship.
References
Footnotes
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Funding Arthritis Research UK.
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Competing interests The authors declare no competing interests.
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Provenance and peer review Not commissioned; externally peer reviewed.