Should we think about wrist extensor after flexor tendon repair?

Comparison of two different orthoses used in the treatment of lateral epicondylitis

BACKGROUND

Lateral epicondylitis (LE) is one of the most common causes of lateral elbow pain, and orthoses are often used in its conservative treatment. However, the number of studies examining the effectiveness of the orthoses used and their differences compared to each other is limited.

OBJECTIVE

To determine the effects of 2 orthoses types, wrist orthosis (WO) and counterforce brace (CB), commonly used in the treatment of lateral epicondylitis on muscle activation, grip strength, hand function, and satisfaction level in healthy individuals.

STUDY DESIGN

Quasi-experimental study.

METHODS

Thirty-seven healthy individuals were recruited. Muscle activation was evaluated by surface electromyography, and maximum grip strength was evaluated with a handheld dynamometer. Hand function and satisfaction level were evaluated with Jebsen Taylor Hand Function Test and Orthotics and Prosthetics Users Survey, respectively. All evaluations were conducted for each individual in 3 conditions (no orthosis, WO, and CB).

RESULTS

Extensor carpi radialis (ECR) muscle activation was greater when using CB compared with that when without orthosis (p = 0.036). There was no significant difference in extensor digitorum communis (EDC) muscle activation and maximum grip strength among the conditions (p > 0.05). Hand function was worse when using the WO compared with the other conditions (p < 0.001). In terms of orthosis satisfaction, individuals were found to be significantly more satisfied with the use of CB (p = 0.001).

CONCLUSIONS

In our study highlight the use of CB in terms of EDC muscle activity, grip strength, hand function, and satisfaction, while the use of WO is prominent in terms of keeping extensor carpi radialis muscle activity low, which has been shown to be important for LE. To obtain definitive results on the effectiveness of different orthoses in the treatment of LE, more research is needed to compare the muscular activation in the extensor carpi radialis brevis (ECRB) and EDC muscles with objective methods.

Influência da órtese estática de punho na atividade muscular e amplitude de movimento de ombro e cotovelo durante uma tarefa funcional: estudo biomecânico

RESUMO As órteses são recursos terapêuticos indicados para proteger, corrigir deformidades ou auxiliar em certas funções; porém, seu uso pode acarretar compensações proximais no ombro. O objetivo deste estudo é avaliar a influência da órtese estática dorsal do punho, em 30° de extensão na biomecânica do ombro e cotovelo, em 25 voluntários assintomáticos durante uma tarefa funcional. Os dados da amplitude de movimento e ativação muscular foram adquiridos de forma sincronizada e simultânea durante parte do teste funcional Elui, que simula alimentação, dividida em alcance, deslocamento e liberação, de uma jarra, nas condições sem e com órtese. Para possibilitar a comparação entre os diferentes sujeitos e músculos, os dados foram analisados pela integral do sinal EMG de cada músculo e, para análise cinemática, foram construídos sistemas de coordenadas de marcadores pré-definidos. Os sinais captados foram filtrados e processados por um software personalizado, e utilizou-se o teste t para amostras pareadas - software SPSS, p<0,05. Notou-se um aumento significativo da ativação dos músculos deltoide anterior e peitoral maior na fase de alcance, e trapézio superior, deltoide anterior e posterior na fase de liberação com a órtese. A cinemática mostrou aumento significativo na amplitude de movimento na abdução do ombro, flexão do cotovelo e pronação do antebraço na fase de deslocamento, e dos movimentos extensão do ombro e flexão do cotovelo na fase de liberação. Nossos achados sugerem que o uso da órtese estática do punho durante a execução de uma tarefa pode acarretar compensações, com predomínio da ativação dos músculos mais proximais do membro superior.

Fadiga dos músculos extensores do punho diminui a força de preensão palmar

RESUMO O objetivo deste estudo foi avaliar os efeitos de um protocolo de fadiga dos músculos extensores de punho na força de preensão e da pinça lateral através da dinamometria e eletromiografia de superfície (EMG). Foram selecionados 40 indivíduos do sexo masculino, divididos em dois grupos: preensão ou pinça lateral. O protocolo de fadiga foi baseado no teste de 1 Repetição Máxima (1-RM), seguido da realização do movimento de extensão de punho repetidas vezes com carga de 75% da 1-RM. Os voluntários realizaram as tarefas de preensão ou pinça lateral associadas à dinamometria. A EMG foi realizada para ambos os grupos, analisando o comportamento, segundo o protocolo, pela frequência mediana (FM) do extensor radial do carpo (ERC), do extensor ulnar do carpo (EUC) e do flexor superficial dos dedos (FD). A dinamometria de preensão ou pinça lateral e a EMG foram realizadas antes e após o protocolo de fadiga para ambos os grupos. O protocolo de fadiga foi eficaz na diminuição da força de preensão palmar (43,5±3,85 kgf inicial e 36,50±5,1 kgf final) e da pinça lateral (10,26±1,01 kgf inicial e 8,54±0,86 kgf final), bem como na diminuição da FM, sugerindo uma condição de fadiga do EUC no grupo preensão. Os achados do presente estudo possibilitam relacionar a fadiga dos extensores de punho à diminuição de força em atividades funcionais, como a preensão, o que pode implicar em disfunções musculoesqueléticas do membro superior.

The influence of different non-articular proximal forearm orthoses (brace) widths in the wrist extensors muscle activity, range of motion and grip strength in healthy volunteers

PURPOSE

The purpose this study was perform a biomechanical evaluation to compare the influence of commercial models of different non-articular proximal forearm orthoses widths (2.5 cm, 5.5 cm, 7.5 cm and 12.0 cm) in the extensor muscle activation, range of motion and grip strength in healthy subjects.

METHODS

Was analyzed data from extensor carpi radialis, extensor carpi ulnares and extensor digitorum comunis using surface electromyography, simultaneous with a wrist electrogoniometer MiotecTM and a hydraulic dynamometer JamarTM. The sequence of tests with all the commercial orthoses models was randomized. Statistics analyses were performed by linear model with mixed effects.

RESULTS

According to our findings the non-articular proximal forearm orthoses (2.5 cm - narrowest) positioned close to lateral epicondyle provided lesser muscle activation on extensor carpi radialis brevis/longus and extensor digitorum comunis, decreased wrist extension and grip strength during submaximal grip task (p< 0.01).

CONCLUSIONS

A narrow non-articular proximal forearm orthosis positioned close to the lateral epicondyle might decrease the extensor muscle activation and therefore could reduce mechanical stress on its insertion, based on this sample. Clinical studies must be conducted to confirm these findings.

Upper extremity coordination strategies depending on task demand during a basic daily activity

Injury conditions affecting the upper extremity may lead to severe functional impairment and an accurate evaluation is needed in order to select the most effective treatment in a rehabilitation program. This study focused on simultaneous electromyographic and kinematic analysis to assess movement patterns of upper extremity during a basic daily activity, considering different demands existing within the task. Twenty-five healthy subjects, average age 19.8 ys SD 1.7 ys, with no upper extremity impairment, were assessed by means of electromyography (EMG) and a 3D motion capture system while performing a task that required reach, transport and release. Integrated EMG (iEMG), timing of muscle onset and active range of motion (AROM) were calculated for each subject. Data were compared within each phase and between the three phases and a repeated measure ANOVA was used for statistical analysis. We found early activation of upper trapezius associated with high activity of serratus anterior for proximal stability while anterior deltoid and triceps brachii performed shoulder flexion and elbow extension, in Reach phase. In Transport phase there was early and higher activation of upper trapezius, higher muscle activity of almost all muscles and increased AROM of all joints. No change in flexion/extension wrist posture with increased forearm muscles activity were identified as the main control strategy to keep optimal grasping. Triceps brachii was found to act as an important synergist in shoulder abduction and extension in free load conditions. Such information can lead clinicians to more specific assessment and subsequent better intervention in upper extremity rehabilitation.

Influence of volar and dorsal static orthoses in different wrist positions on muscle activation and grip strength in healthy subjects

Introduction

Orthoses are indicated for injuries of the wrist, although there is weak evidence for its influence on extensor muscle activation patterns. The purpose of this study was to compare two designs of volar and dorsal wrist orthoses in several positions, from flexion to extension, by surface electromyography wrist extensor muscle activation and grip strength in healthy subjects.

Methods

We analysed extensor carpi radialis brevis and longus, extensor carpi ulnaris and extensor digitorum comunis muscle activity by surface electromyography. The volunteers performed maximum and submaximum (50%) isometric grips, which were evaluated with a Jamar™ dynamometer using volar and dorsal orthoses with several positions of the wrist (0°, 15° and 30°), both in flexion and extension ( p < 0.05).

Results

Our results showed a significant decrease in extensor muscle activation at 15° and 30° of wrist extension in both volar and dorsal orthoses at 100% and 50% of maximum task. A decrease was also found at rest at 15° of wrist flexion volar orthoses. Decreased grip strength was found at 15° and 30° of wrist flexion in both volar and dorsal orthoses.

Conclusions

Based on the results of this sample, we would suggest, as orthotic prescriptions, 15° or 30° wrist extension orthoses as a supporting therapeutic modality for performance in new studies with lateral epicondylitis in association with low-intensity grip activity; or 15° of wrist flexion volar orthoses for rest, depending on the chronicity of the disease and individual assessment. Future studies with symptomatic patients are needed to confirm these findings.