Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA).METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed.RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143).CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA.

Knee extensor torque of men with early degrees of osteoarthritis is associated with pain, stiffness and function / Homens com graus iniciais de osteoartrite apresentam correlação entre torque extensor do joelho e dor, rigidez e função

BACKGROUND: Osteoarthritis (OA) is a chronic-degenerative disease. The knee is the most commonly affected joint and the symptoms are generally attributed to quadriceps muscle weakness. However, few studies have evaluated this relationship in a population with early stages of knee OA. OBJECTIVE: To investigate whether a correlation among the knee extensor torque and the three subscales of the WOMAC questionnaire in men with early stages of knee OA exists. METHOD: Twenty-one men with knee OA grades I or II (according to Kellgren and Lawrence criteria) participated in this study. The concentric and eccentric knee extensor torque were assessed using a Biodex System 3 Pro® isokinetic dynamometer, at a speed of 90º/s. Self-reported symptoms and disability were assessed using the WOMAC questionnaire. Spearman's correlation coefficient was used to test the relationship between the dependent variables (three subscales of WOMAC questionnaire) and the independent variables (average knee extensor peak torque). RESULTS: We found a strong negative correlation between the concentric extensor torque and pain (r=-0.7, p<0.001) and a moderate and negative correlation among the concentric extensor torque and stiffness (r=-0.62, p=0.002) and physical function (r=-0.54, p=0.011). Eccentric extensor torque presented a moderate and negative correlation with the three subscales of the WOMAC (r=-0.40 to 0.69, p<0.05). CONCLUSIONS: The concentric and eccentric knee extensor torque is significantly correlated with self-report symptoms of patients in initial stages of knee OA. Therefore, the strengthening of the quadriceps muscles, through concentric and eccentric exercise is indicated for these patients in order to minimize these symptoms.

CONTEXTUALIZAÇÃO: A osteoartrite (OA) é uma doença crônico-degenerativa. O joelho é a articulação mais afetada, e os sintomas geralmente são atribuídos à fraqueza do músculo quadríceps. Entretanto, poucos estudos têm avaliado essa relação em indivíduos com graus iniciais de OA. OBJETIVO: Verificar se existe correlação entre o torque extensor do joelho e as seções dor, rigidez e função física do questionário WOMAC de homens com OA de joelho nos graus iniciais. MÉTODO: Participaram deste estudo 21 homens com OA de joelho graus I ou II (segundo critérios de Kelgren e Lawrence). Foi avaliado o torque extensor concêntrico e o excêntrico do joelho por meio do dinamômetro isocinético (Biodex System 3 Pro®), na velocidade de 90º/s. O autorrelato de sintomas e incapacidades foi avaliado por meio do questionário WOMAC. O Coeficiente de Correlação de Spearman foi utilizado para detectar a relação entre as variáveis dependentes (três seções do questionário WOMAC) e as variáveis independentes (média dos picos de torque). RESULTADOS: Encontrou-se correlação forte e negativa do torque extensor concêntrico com a seção dor (r=-0,7, p<0,001) e moderada e negativa com as seções rigidez (r=-0,62, p=0,002) e função física (r=-0,54, p=0,011). O torque extensor excêntrico correlacionou-se moderada e negativamente com as três seções do questionário (r=-0,40 a -0,69, p<0,05). CONCLUSÕES: Os torques extensores concêntrico e excêntrico correlacionaram-se com os sintomas autorrelatados pelos indivíduos com graus iniciais de OA de joelho. Assim, o fortalecimento do músculo quadríceps, por meio de exercícios concêntricos e excêntricos, é indicado para esses pacientes para minimizar tais sintomas.

Efeito de exercícios terapêuticos no equilíbrio de mulheres com osteoartrite de joelho: uma revisão sistemática / The effects of therapeutic exercise on the balance of women with knee osteoarthritis: a systematic review

OBJETIVO: Fornecer evidências relacionadas ao efeito de exercícios terapêuticos sobre o equilíbrio de mulheres com osteoartrite (OA) de joelho. MÉTODOS: A busca foi realizada nas bases de dados Pubmed, Medline, Lilacs, SciELO, ISI web of knowledge, PEDro e Colaboração Cochrane. Foram utilizadas as palavras-chave: knee, balance, women, rehabilitation em combinação com osteoarthritis. Foram selecionados ensaios clínicos aleatórios e controlados dos últimos dez anos, em língua inglesa, portuguesa e espanhola. Para verificar a qualidade dos ensaios clínicos selecionados, aplicou-se a Escala PEDro. RESULTADOS: Encontrou-se um total de 20 estudos a partir da busca eletrônica. Desses, apenas nove satisfizeram os critérios de inclusão e foram analisados integralmente. A avaliação da qualidade metodológica dos nove estudos incluídos permitiu classificar oito deles como de alta qualidade metodológica. Os métodos e as intervenções para o equilíbrio variaram amplamente, no entanto a maioria dos estudos encontrou melhora significativa no equilíbrio de mulheres com OA de joelho. CONCLUSÃO: Como os estudos incluídos nesta revisão sistemática têm uma alta qualidade metodológica, pode-se concluir que os exercícios terapêuticos utilizados pelos estudos melhoraram o equilíbrio de mulheres com OA de joelho.

OBJECTIVE: The objective of this review was to examine evidence regarding the effects of therapeutic exercise on the balance of women with knee osteoarthritis (OA). METHODS: The search was conducted in Pubmed, Medline, Lilacs, SciELO, ISI web of knowledge, PEDro and the Cochrane Collaboration. We used the keywords: "knee", "balance", "women" and "rehabilitation" in combination with "osteoarthritis". We selected randomized controlled clinical trials published in English, Portuguese and Spanish over the last 10 years. To verify the methodological quality of selected clinical trials, the PEDro Scale was applied. RESULTS: A total of 20 studies were found in the electronic search. Of these, only 9 met the inclusion criteria and were analyzed in full. Eight of these 9 studies were classified as having high methodological quality on the PEDro Scale. Although the methods and interventions regarding balance varied widely in these studies, most found significant improvement in the balance of women with knee OA. CONCLUSION: Since the studies included in this systematic review were of high methodological quality, we can conclude that the therapeutic exercises they used improved the balance of women with knee OA.