A new therapeutic target in equinus: Botulinum toxin injection (Dysport®) in peroneus longus

Abstract

Introduction: Functions are generally developed through the kinetic chain and require the efficient subsequence inmuscles activation [1]. Deficit in neuromuscular control may be a contributing factor to the development of musculoskeletal disorders such as patellofemoral pain syndrome (pfps), which is a common and clinically complicated condition [2,3]. The aim of the present studywas to compare the electromyographic firing pattern of the core and lower extremitymuscles in response to sudden lateral perturbation in patients with pfps and healthy subjects. Patients/materials and methods: 27 females with pfp and 27 healthy controls with no history of knee injuries participated in this interventional study. Subjects were instrumented with EMG electrodes on the erector spine, transverse abdominis and internal oblique, gluteus medius, tensor fascia lata, vastus lateralis, vastus medialis obliqus andperoneus longus.Onsets of electromyographic activation of the selected muscles were measured by surface EMG, ME6000 16-channel system(Kistler Ltd.Finland) in response to an unexpected mediolateral pelvic perturbation in standing position. Independent t-test was used to compare each muscle’s mean onset latency between groups. The muscle activation pattern in each group was analyzed by a nonparametric friedman test and wilcoxon signed ranks test. Results: Females with patellofemoral pain syndrome demonstrated delayed onset of gluteusmedius (p=0.025), vastusmedialis obliqus(p=0.033) and vastus lateralis(p=0.024) and earlier activation of internal oblique and transverse abdominis(p<0.001) and also erector spine (p=0.001), than the control group. The muscles indicated significantly different activation time within groups(p<0.001). Discussion and conclusions: This study provides evidence that neuromuscular control and muscle activation pattern are different between individuals with pfps and healthy subjects. It appears that evaluating the entire kinetic chain rather than focusing on the action of a particular segment is necessary to identify the compensatory strategies of control system.