April 2019

New Tool to Assess Clubfoot Treatment

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Congenital talipes equinovarus, or clubfoot, is a common deformity in which the affected foot is fixed downward and inward. The birth prevalence of clubfoot in low- and middle-income countries is estimated to be 0.5 to 2.0 cases for every 1000 live births.

There is a global trend toward use of the minimally invasive Ponseti method for the correction of clubfoot, consisting of simultaneous correction of the components of the clubfoot deformity with manipulation and casting. A percutaneous tenotomy of the Achilles tendon is usually required to correct the residual equinus. A foot abduction brace is then needed to maintain the corrected position until 4 years of age (the clubfoot deformity has a strong tendency to recur after corrective treatment because the factors that initiate the deformity remain active as the child grows). Recurrent elements of the deformity are less common after the child is 4 years old because the rate of growth of the foot decreases.

In low-resource settings, nonspecialist health workers are trained as clubfoot therapists. They assess, diagnose, treat, and follow up patients with clubfoot. Several scoring systems have been described for clubfoot, but none have been validated to identify children with recurrent clubfoot who require intervention in a low-resource setting. There remains a need for a valid, repeatable, and easy-to-administer tool that will allow clubfoot therapists to differentiate a good outcome of treatment from a less acceptable outcome that needs further intervention.

To address this gap, researchers from the United Kingdom and Africa sought to develop a user-friendly, comprehensive tool to assess children of walking age who have undergone Ponseti treatment for clubfoot.

Using a literature review and a Delphi (consensus) method based on the opinions of 35 Ponseti trainers, the team developed the Assessing Clubfoot Treatment (ACT) tool and score (Table). Children treated between 2011 and 2013 were followed up in 2017. A full clinical assessment was conducted to determine whether treatment was successful or if further treatment was required. The ACT score was then calculated for each child. Interobserver variation for the ACT tool was assessed. Sensitivity, specificity, and positive and negative predictive values were calculated for the ACT score, compared to the gold standard of full clinical assessment. Predictors of a successful outcome were explored.

The follow-up rate was 31.2% (68 children). The ACT tool comprised 4 questions; each question was scored from 0 to 3, giving a total scoring of 0 to 12, with 12 being the ideal result. The 4 questions included 1 physical assessment and 3 parent-reported outcome measures. The tool took 5 minutes to administer and had excellent interobserver agreement.

An ACT score of ≤8 was 79% sensitive and 100% specific in identifying children that required further intervention (positive predictive value, 100%; negative predictive value, 90%). Children who completed ≥2 years of bracing were 4 times more likely to achieve an ACT score of ≥9, compared to those who did not (odds ratio, 4.08 [95% confidence interval, 1.31-12.65; P = .02]).

The ACT tool is simple to administer and has excellent observer agreement and good sensitivity and specificity in identifying children who need further intervention. The score can be used to identify children who definitely need referral and further treatment (score, ≤8) and those with a definite successful outcome (score, ≥11). Further discrimination is needed, however, to decide how to manage children with a borderline ACT score of 9 or 10.

Excerpted from: Smythe T, Mudariki D, Gova M, Foster A, Lavy C. Evaluation of a simple tool to assess the results of Ponseti treatment for use by clubfoot therapists: a diagnostic accuracy study. J Foot Ankle Res. 2019 Mar 4;12:14. (Use is per the Creative Commons License CC BY 4.0.)

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