Ajustes posturais antecipatórios adotados por indivíduos com osteoartrite de joelho no início da marcha: efeito do nível de severidade e tratamento

Abstract

Background: Gait initiation is a functional task that requires anticipatory postural adjustments. The ability to generate adequate postural adjustments can be compromised in individuals with advanced age and musculoskeletal disorders, such as knee osteoarthritis (KOA), increasing their risk of falling. KOA is a degenerative joint disease characterized by the presence of pain, stiffness, and deficit in strength and postural balance. The symptoms are more evident as KOA progresses and can affect functional performance and the way these individuals walk. Therefore, individuals with KOA may present with altered postural adjustments, and these changes can be aggravated according to the level of severity of the disease. Although regular exercises are high recommended in the management of KOA, there are no records of their effect on postural adjustments in this population during gait initiation. Objective: to compare the anticipatory postural adjustments adopted by individuals with different levels of KOA severity in the gait initiaton, and to compare the effects of resistance and aerobic exercise program and minimal intervention on postural adjustments, pain intensity, strength and physical function. Methods: Sixty-seven individuals with KOA (mild, moderate and severe levels) and eleven healthy controls were submitted to pain intensity assessment, self-reported physical performance, muscle strength and anticipatory postural adjustments adopted in the gait initiation, through the Numerical Pain Scale, Westerm Ontario and McMaster Universities, isometric muscle strength test and posturography, respectively. Among the individuals with KOA, 64 underwent a program of resistance exercises, aerobics, and minimal interventions, and were assessment after the intervention. The exercise program was performed three times a week for eight weeks. The resistance exercises consisted of strengthening with progressive of the hip abductor muscles, quadriceps femoris and tibialis anterior (four sets of six repetitions). Resistance exercises consisted of 40 minutes in the stationary bicycle, with an intensity of approximately 70% of maximum heart rate. Other hand, the minimal intervention consisted in the education program and home execution of part of the exercise protocol. Results: Our findings showed that during gait initiation, individuals with moderate and severe levels of KOA, when compared to the healthy control group, adopt slower and longer-lasting anticipatory postural adjustments, less displacement of the center of pressure and a shorter phase of locomotion. After submitted eight weeks of resistance and aerobic exercises, individuals with KOA showed less posterolateral displacement and longer duration of mediolateral displacement of the center of pressure at the gait initiation.

Additionally, they demonstrated less pain intensity, greater muscle strength and better functional performance. At the same time, individuals with KOA submitted to minimal intervention demonstrated less duration of posterolateral displacement of the center of pressure and locomotor phase, and better functional performance. Conclusions: Individuals with KOA, in order to protect the joint, change the patterns of anticipatory postural adjustments during gait initiation, and such adjustments are significantly worsened by the level of severity of KOA. Interventions based on resistance and aerobic exercises and education produce few change in the pattern of anticipatory postural adjustments at the gait initiation, and significantly improve the clinical presentation of this population.