Evertor muscle activity as a predictor of the mid-term outcome following treatment of the idiopathic and non-idiopathic clubfoot

Abstract

Previous studies have identified clinical and demographic risk factors for recurrence in the treatment of idiopathic clubfoot (congenital talipes equinovarus). Evertor muscle activity is not usually considered amongst them. This study aimed to evaluate whether recurrence could be predicted by demographic, clinical and gait parameters. From a series of 103 children with clubfeet, 67 had completed a follow-up of two years: 41 male and 26 female, 38 with idiopathic and 29 with non-idiopathic deformities. The mean age was 3.2 years (2.1 to 6.3). Primary correction was obtained in all 38 children (100%) with an idiopathic deformity, and in 26 of 29 patients (90%) with a non-idiopathic deformity. Overall, 60 children (90%) complied with the abduction brace regime. At a mean follow-up of 31.4 months (24 to 62), recurrence was noted in six children (15.8%) in the idiopathic and 14 children (48.3%) in the non-idiopathic group. Significant correlation was found between poor evertor activity and recurrence in both groups. No statistically significant relationship was found between the rate of recurrence and the severity of the initial deformity, the age at the time of treatment, the number of casts required or the compliance with the brace. After correction of idiopathic and non-idiopathic clubfoot using the Ponseti method, only poor evertor muscle activity was statistically associated with recurrence. The identification of risk factors for recurrent deformity allows clinicians to anticipate problems and advocate early additional treatment to improve muscle balance around the ankle.

Evolution of clubfoot deformity and muscle abnormality in the Ponseti method: evaluation with the Dimeglio score

“…Edmonds and Frick [26] described the drop toe sign in nine [13] reported complex idiopathic deformity in 50 out of 762 clubfoot patients (6.5%). Poor evertor muscle activity was reported in 19 out of 59 idiopathic clubfeet (32.2%) following primary correction by Gelfer et al [29]. On the other hand, Chaudhry et al [22] using the Dimeglio score reported no case of positive MA parameter at presentation in their study, which we consider to be unlikely.…”

“…Muscular abnormalities are not uncommon in clubfeet [27][28][29] and a primary role of muscle impairment in the aetiopathogenesis of clubfoot has been suggested [30]. Several pathologic and clinical studies have shown in muscles of most clubfeet variably increased fibrous tissue (mainly in gastrosoleus, tibialis posterior and long toe flexor) [1,27] and atrophy, which is primitive and already present before starting treatment [27].…”

“…A more marked involvement has been described in treatment-resistant clubfeet (increased epimysial fat sharply demarcating muscle compartments, diffuse intramuscular fat replacement and hypoplasia or aplasia of a specific muscle group [23,24]) and in complex clubfeet (with fibrosis extending to plantar intrinsic muscles [13]). Muscular imbalance due to hypertonic tibialis anterior (secondary to hyperactivity or abnormal insertions) or to inactive peroneal muscles (secondary to hypoplasia/aplasia or to mechanical disadvantage produced by the deformity) is not infrequent and has been correlated with risk of relapse [28,29,31]. The drop toe sign (resting posture of the toes in plantarflexion and absent active dorsiflexion movement after plantar stimulation of the foot) has been suggested [26] to be an indicator of abnormalities of either the anterior leg musculature or its innervating nerve and to be predictive of treatment resistance [23,26].…”

“…Evaluation of muscle condition is performed clinically and consequently is quite subjective [29,33] and influenced by global stiffness of other tissues (ligaments, tendons). Muscle condition should be differentiated at presentation from severity of deformity, since these features are not necessarily correlated [13,27]: in our cohort several feet showed persistent MA and only mild adductus or heel varus at presentation.…”

What is new in idiopathic clubfoot?

“…The presence of this anomalous muscle may increase the likelihood of clubfoot being resistant to casting treatment [30]. Additionally, poor eversion muscle activity qualitatively assessed on physical exam has been demonstrated as a risk factor for relapse of clubfoot [31].…”