Flexor digitorum accessorius longus muscle in resistant clubfoot patients

Abstract

Clubfoot, talipes equino varus (TEV), is a common congenital foot anomaly. Some cases are resistant to conservative treatment. Many causes of resistance have been reported, among these, the presence of anomalous muscles; however, the effect of the presence of anomalous muscles on the outcome of conservative management is not well studied. These aberrant muscles are discovered during the extensive surgical release as an abnormal finding. The aim of this work is to study the demographic characteristics of patients with resistant TEV that necessitated extensive soft tissue release at Sudan Clubfoot Clinic and to document the prevalence of flexor digitorum accessorius longus (FDAL) muscle in a large series of clubfoot patients treated by extensive surgery: posteromedial release. Also, we introduce a new observation as an indication by which the surgeon can predict the presence of FDAL. On the basis of an observation that there is a special posture of the big toe in extension in relation to other flexed toes associated with the presence of FDAL, records of patients of clubfoot treated by extensive surgery between 2007 and 2012 at the Sudan Clubfoot Project were reviewed. Demographic characteristics were studied. Only patients with idiopathic TEV were included. Resistant clubfeet necessitated extensive release in 261 patients, 197 males and 64 females. Their ages ranged between 1 day and 15 years at presentation. FDAL muscle was found in 48 patients (54 feet) out of 261 patients (411 feet, 13.14%). In 46 of the 48 patients (95.8%), the presence of the FDAL could be predicted by a sign. FDAL is prevalent in 13% of resistant TEV cases requiring extensive soft tissue release, and the surgeon can expect resistant clubfoot and predict the presence of the FDAL in over 95% before he operates by observing the Samir-Adam sign.

The Association between Anatomical Variants of Musculoskeletal Structures and Nerve Compressions of the Lower Limb: A Systematic Review and Meta-Analysis

“…Moreover, one patient presented subluxation of the tendons of the peroneal muscles. The presence of an accessory flexor digitorum longus muscle was described in 18 studies of different characteristics [71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. In most cases, its presence was associated with tarsal tunnel syndrome, which is triggered by the compression of the tibial nerve within the tarsal tunnel, as this accessory muscle compresses the nerve.…”

What is new in idiopathic clubfoot?

“…The BSamir-Adam sign,^which is a relatively extended big toe compared to the lesser digits, is highly predictive of a flexor digitorum accessorius longus muscle. 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].…”