Classification systems for hallux rigidus: a review of the literature

BACKGROUND: Hallux rigidus (HR) is one of the most common causes of forefoot pain. A number of classification systems have been developed to evaluate HR. These systems are based on either radiological parameters alone or a combination of radiological and clinical features. The purpose of this paper is to critically evaluate HR classification systems by undertaking a detailed review using English language medical and paramedical databases. MATERIALS AND METHODS: The authors identified 18 formal HR classification systems described in the literature, some of which are variations on a theme. RESULTS: No clear consensus on the construction of HR classification systems appears to exist. Different criteria and methods are used which make comparison difficult. Furthermore, it appears that, no serious consideration has been given to their reliability and validity. Criteria used to justify inclusion of these parameters have been based mainly on clinical experience rather than formal research. CONCLUSION: For such a common condition, there is a need for a properly constructed, prospective study to develop a suitable classification system. It should include scientifically validated parameters to help stratify different stages of the disease and aid clinical and scientific communication.