The inter-relationship of clinical parameters in congenital talipes equinovarus: relevance to pathological anatomy and clinical classification.

BACKGROUND: The clinical features that define congenital talipes equinovarus (CTEV) are the presence of four principal components, equinus, varus, adductus and cavus. Classification systems in CTEV often include a form of assessment of these components and also other concurrent clinical parameters which feature in the condition.

METHODS: Over a 14-year period from 1992 to 2006, 95 consecutive cases of CTEV were prospectively assessed and data recorded in order to investigate the relationships between the clinical parameters in CTEV and to compare these relationships with those that one would expect from our knowledge of the pathological anatomy and mechanics of the condition, relating these findings to the commonly used systems for classification.

RESULTS: Ninety-five cases of CTEV had failed conservative treatment and had undergone surgical release. The mean age at surgical release and assessment was 9 months. Cluster analysis demonstrated that there were, broadly, two groups of patients. The first group was those patients with a greater equinus deformity (greater than 31°). This group had a greater adductus deformity and the presence of other parameters indicating increased severity (multiplanar stiffness with the presence of cavus and medial skin crease). The second group was those patients with a smaller equinus deformity (less than 31°) who were more heterogenous with regards to the other parameters.

CONCLUSIONS: We analysed on a statistical basis the relevant aspects of the deformity in CTEV. We have demonstrated that there are certain parameters, namely, equinus and adductus, whose severity can reasonably predict the severity of other components of the deformity. With regards to hindfoot parameters, increased equinus is related to less sagittal plane reducibility and to stiff hindfoot varus (coronal plane stiffness). In terms of midfoot parameters, the degree of adductus is related to the presence of cavus deformity and the presence of a medial skin crease is associated with less reducibility of the adductus (axial plane stiffness). This is consistent with our current understanding of the pathological anatomy of CTEV and bears implications with regards to treatment and the design of proposed classification systems that are in use.