Influência da hiperalgesia na atividade muscular e controle postural durante o agachamento umpodal em indivíduos com osteoartnte de joelho

Abstract

Introduction: The main symptom of knee osteoarthritis (OA) is the pain. If it is not controlled, it can become chronic and affects its processing in the spinal cord and at the cortical level, which turns out being hyperalgia in dermatomes, myotomes and sclerotomes. This hyperalgesia could be correlated with changes in the muscle activity and postural control during unipodal squatting, which is considered a difficult movement and painful for individuals who have the disease. Understanding these correlations could be important for more effective therapeutic approaches. Objectives: Verify if hyperalgesia would be correlated with muscular activity and postural control, besides evaluating these variables during unipodal squatting comparing healthy individuals and individuals with KOA. Material and methods: Sixty individuals participated in the study: healthy group (HG n = 30, Age: 57.4 ± 6.86) and group with KOA (KOA n = 30, Age: 59.4 ± 5.46). The KOA should meet the diagnostic criteria of the American College of Rheumatology, experiencing uni or bilateral KOA at a mild to moderate affect. The pain was evaluated using the WOMAC questionnaire, the pain visual analog scale (VAS) and the Pressure Pain Threshold (PPT) in dermatomes, myotomes and sclerotomes; the muscle activity was assessed by means of surface electromyography in the muscles: gastrocnemius medial (GM), femoral biceps (BF), erector spinae (longissimus) (EEL), gluteus medius (GLM), femoral rectus (RF), vastus medialis (VM), vastus lateralis (VL); and tibialis anterior (TA) from the dominant lower limb in healthy individuals or in the affected lower limb or with greater pain in individuals with KOAJ. The postural control variables were evaluated by the force platform. The muscle activity evaluation and postural control were performed after pain evaluation and during unipodal squatting. Results: In individuals with KOA, the correlation between hyperalgesia and electromyographic activity (rho < 0.482; p = 0.000) and hyperalgesia and postural control (rho < -0.436; p = 0.000) were weak to moderate during unipodal squatting, although these individuals presented lower pain thresholds (p < 0.005) and greater muscle activity for some muscles (p < 0.027) when compared to individuals without the disease. Strong correlations were found between LDPs, EVA and WOMAC, as in the dermatome L4 (EVA = rho 0.695; WOMAC = 0.701), AL myotome (EVA = rho 0.557; WOMAC = 0.594) and sclerotome TP (EVA = rho 0.565; WOMAC = 0.507). Conclusion: Although hyperalgesia is present in individuals with mild and moderate KOA, it does not correlate with the electromyographic activity and postural control during unipodal squatting. However, some PPTs may predict the level of peripheral and central pain in individuals with KOA.