Biologic therapies for foot and ankle injuries.

Introduction: The use of orthobiologics as supplemental treatment for foot and ankle pathologies have increased in the past decades. They have been used to improve the healing of bone and soft tissue injuries. There have been several studies that examined the use of biologics for knee and hip pathologies but the foot and ankle construct has unique features that must be considered.Areas covered: The biologics for foot and ankle injuries that are covered in this review are platelet-rich plasma (PRP), stem cells, growth factors, hyaluronic acid, bone grafts, bone substitutes, and scaffolds. These modalities are used in the treatment of pathologies related to tendon and soft tissue as well as cartilage.Expert opinion: The utilization of biological adjuncts for improved repair and regeneration of ankle injuries represents a promising future in our efforts to address difficult clinical problems. The application of concentrated bone marrow and PRP each represents the most widely studied and commonly used injection therapies with early clinical studies demonstrating promising results, research is also being done using other potential therapies such as stem cells and growth factors; further investigation and outcome data are still needed.

Application of Empirical Mode Decomposition Combined With Notch Filtering for Interpretation of Surface Electromyograms During Functional Electrical Stimulation.

The goal of this paper is to demonstrate a novel approach that combines Empirical Mode Decomposition (EMD) with Notch filtering to remove the electrical stimulation (ES) artifact from surface electromyogram (EMG) data for interpretation of muscle responses during functional electrical stimulation (FES) experiments. FES was applied to the rectus femoris (RF) muscle unilaterally of six able bodied (AB) and one individual with spinal cord injury (SCI). Each trial consisted of three repetitions of ES. We hypothesized that the EMD algorithm provides a suitable platform for decomposing the EMG signal into physically meaningful intrinsic mode functions (IMFs) which can be further used to isolate electrical stimulation (ES) artifact. A basic EMD algorithm was used to decompose the EMG signals collected during FES into IMFs for each repetition separately. IMFs most contaminated by ES were identified based on the standard deviation (SD) of each IMF. Each artifact IMF was Notch filtered to filter ES harmonics and added to remaining IMFs containing pure EMG data to get a version of a filtered EMG signal. Of all such versions of filtered signals generated from each artifact IMF, the one with maximum signal to noise ratio (SNR) was chosen as the final output. The validity of the filtered signal was assessed by quantitative metrics, 1) root mean squared error (RMSE) and signal to noise (SNR) ratio values obtained by comparing a clean EMG and EMD-Notch filtered signal from the combination of simulated ES and clean EMG and, 2) using EMG-force correlation analysis on the data collected from AB individuals. Finally, the potential applicability of this algorithm on a neurologically impaired population was shown by applying the algorithm on EMG data collected from an individual with SCI. EMD combined with Notch filtering successfully extracted the EMG signal buried under ES artifact. Filtering performance was validated by smaller RMSE values and greater SNR post filtering. The amplitude values of the filtered EMG signal were seen to be consistent for three repetitions of ES and there was no significant difference among the repetition for all subjects. For the individual with a SCI the algorithm was shown to successfully isolate the underlying bursts of muscle activations during FES. The data driven nature of EMD algorithm and its ability to act as a filter bank at different bandwidths make this method extremely suitable for dissecting ES induced EMG into IMFs. Such IMFs clearly show the presence of ES artifact at different intensities as well as pure artifact free EMG. This allows the application of Notch filters to IMFs containing ES artifact to further isolate the EMG. As a result of such stepwise approach, the extraction of EMG is achieved with minimal data loss. This study provides a unique approach to dissect and interpret the EMG signal during FES applications.

Neuromotor response of the leg muscles following a supine, stand retraining with/without neuromuscular electrical stimulation training intervention for individuals with SCI: A case series.

The goal of this paper is to study the effects of supine and stand retraining (SRT) interventions with and without multi muscle neuromuscular electrical stimulation (NMES) on the neuromuscular EMG responses of the leg muscles for individuals with motor complete SCI during walking on a body-weight support (BWS) treadmill. The main outcome variables were EMG amplitude, integrated EMG and co-contraction indices (co-excitation and co-activation) collected during a 10-minute walking treadmill trial. Data was analyzed for the first, fifth and tenth minute of walking. Results showed that both Supine+NMES and SRT+NMES interventions increased spatial-temporal aspects of muscle activity (mean EMG amplitude and integrated EMG) of lower limb muscles. SRT+NMES (loading) showed greater gains in the proximal anterior leg compartments. On the contrary, SRT without NMES (SRT only) exhibited deterioration of activity within the same muscle groups. Co-contraction indices increased for both post-NMES interventions suggesting that task-specificity of training is important to achieve the fundamental reciprocal firing known to able-bodied gait. These results show that combination of NMES+loading during passive rhythmic gait will induce neuroplasticity in the lower limbs that ultimately provides a potential effective means to recover gait in individuals with SCI.

Effects of lower limb electrical stimulation on trunk stability in persons with SCI during walking: a case series.

The purpose of the present case series was to investigate whether three lower limb rehabilitation training approaches have any effects on trunk stability of persons with motor complete SCI during a 10-minute assisted walk. These trainings included electrical stimulation (ES), standing retraining (SRT), and a novel multi-modality approach that combined ES with SRT. We observed that multi-muscle ES directed at the lower limbs had a prominent, indirect effect on the upper and lower muscles of the trunk. More specifically, trunk muscle activations of the ES+SRT subject increased after training for the more distal muscles of the trunk. This study provides preliminary evidence that combining lower limb ES with SRT may provide beneficial effects in improving trunk control and stability.