The clubfoot assessment protocol (CAP); description and reliability of a structured multi-level instrument for follow-up

Abstract

BackgroundIn most clubfoot studies, the outcome instruments used are designed to evaluate classification or long-term cross-sectional results. Variables deal mainly with factors on body function/structure level. Wide scorings intervals and total sum scores increase the risk that important changes and information are not detected. Studies of the reliability, validity and responsiveness of these instruments are sparse. The lack of an instrument for longitudinal follow-up led the investigators to develop the Clubfoot Assessment Protocol (CAP).The aim of this article is to introduce and describe the CAP and evaluate the items inter- and intra reliability in relation to patient age.MethodsThe CAP was created from 22 items divided between body function/structure (three subgroups) and activity (one subgroup) levels according to the International Classification of Function, Disability and Health (ICF). The focus is on item and subgroup development.Two experienced examiners assessed 69 clubfeet in 48 children who had a median age of 2.1 years (range, 0 to 6.7 years). Both treated and untreated feet with different grades of severity were included. Three age groups were constructed for studying the influence of age on reliability. The intra- rater study included 32 feet in 20 children who had a median age of 2.5 years (range, 4 months to 6.8 years).The Unweighted Kappa statistics, percentage observer agreement, and amount of categories defined how reliability was to be interpreted.ResultsThe inter-rater reliability was assessed as moderate to good for all but one item. Eighteen items had kappa values > 0.40. Three items varied from 0.35 to 0.38. The mean percentage observed agreement was 82% (range, 62 to 95%). Different age groups showed sufficient agreement. Intra- rater; all items had kappa values > 0.40 [range, 0.54 to 1.00] and a mean percentage agreement of 89.5%. Categories varied from 3 to 5.ConclusionThe CAP contains more detailed information than previous protocols. It is a multi-dimensional observer administered standardized measurement instrument with the focus on item and subgroup level. It can be used with sufficient reliability, independent of age, during the first seven years of childhood by examiners with good clinical experience.A few items showed low reliability, partly dependent on the child's age and /or varying professional backgrounds between the examiners. These items should be interpreted with caution, until further studies have confirmed the validity and sensitivity of the instrument.

A Clinical Evaluation of the Pirani and Dimeglio Idiopathic Clubfoot Classifications

“…An ideal classification system should be practical and reproducible (8,9). It should consider the 3-dimensional characteristics of the clubfoot deformation and also be simple enough to be implemented in clinical practice.…”

Multiple health disparities among minority adults with mobility limitations: An application of the ICF framework and codes

“…It offers a framework for describing the interactive effects of functioning, personal activities, social participation, and environmental influences [1]. Among its important features is the potential to standardize communication within the classification scheme across disciplines, assessment tools, and continents [82]. The ICF has been used to create health assessment tools [82 -84] and to identify components in other existing tools that are ICF-related [9,78,83 -90].…”

Comparison of serial casting and stretching technique in children with congenital idiopathic clubfoot: Evaluation of a new assessment system

“…In previous studies, the CAP has been shown to have moderate-to-good reliability and to be valid for use in follow-up of clubfoot (Andriesse et al 2005(Andriesse et al , 2006. 20 items divided into body/function structures (4 domains) and activity levels (two domains) according to the International Classification of Function, Disability and Health (ICF, World Health Organization 2000) form the CAP (Table 1).…”

“…Furthermore, assessment instruments used in clinical studies should have documented reliability and validity, ensuring that these instruments have acceptable methodological quality. Our own literature search on clubfoot instruments using Medline showed that there have been very few studies focusing on reliability and validation (Maffulli et al 1997, Flynn et al 1998, Roye et al 2001, Wainwright et al 2002, Andriesse et al 2005, Celebi et al 2006, Munshi et al 2006, Andriesse et al 2006. This is still an area in need of further development.…”

“…The present study is the first part of a longitudinal follow-up of clubfoot treatment with the use of the Clubfoot Assessment Protocol (CAP) (Andriesse et al 2005). The first objective was to compare the 2-year outcome for the Copenhagen stretching method with that for casting techniques according to Ponseti, the treatment period being the first 2 months after birth.…”