Effects of Including Interferential Current in a Therapeutic Exercise Program in Individuals With Knee Osteoarthritis
Effects of Including Interferential Current in a Therapeutic Exercise Program in Individuals With Knee Osteoarthritis
The first-line treatment for knee osteoarthritis (KOA) in terms of pain and functionality is physical exercise. The use of interferential current (IC) associated with other resources may be beneficial in reducing pain intensity and improving functionality. However, the effects of its simultaneous use with therapeutic exercise have not yet been fully established. The aim of this project will be to evaluate the effects of including IC in a therapeutic exercise program in relation to pain intensity, functionality, self-efficacy, maximum voluntary contraction and overall perceived effect in individuals with KOA. Therefore, research participants of both sexes, between 40 and 75 years old, with a clinical diagnosis of unilateral KOA, who have knee pain for more than 3 months, with a minimum score of 3 points on the numerical pain scale, morning stiffness for less than 30 minutes, crepitation, bone sensitivity, and absence of palpable heat will be recruited. The research participants will be randomized into three groups: therapeutic exercises (n=46) and therapeutic exercises + IC (n=46) and therapeutic exercises + IC placebo (n=46). Eight consecutive weeks of treatment will be carried out. The research participants will be evaluated before the intervention, after the end of the intervention of eight consecutive weeks of intervention and after four weeks at the end of the last week of intervention, through the instruments: numeric pain scale (NPS), Knee Injury and Osteoarthritis Outcome Score (KOOS), patient-specific functional scale (EFEP), Pain self-efficacy questionnaire (PSEQ), maximum voluntary isometric contraction (MVIC), 30-second sit-to-stand test (TSL30s), global perception scale (EPG). For data analysis, a normality test will be used to verify the distribution of the data and a statistical test appropriate for the appropriate intra and inter-group comparisons, thus considering two factors in the comparisons, time and group. A significance level of 5% will be adopted.
The sample size calculation was revised to reflect a more appropriate and accurate outcome: The sample size was calculated based on the study's primary outcome, the Pain subscale of the KOOS. For the calculation, a clinically important difference between groups of 11.8 points was considered, a value derived from a systematic review specific to individuals with knee osteoarthritis undergoing non-surgical interventions, rounded to approximately 12 points for clinical interpretation purposes. A standard deviation of 18.2 points was adopted, based on a study involving individuals with mild to moderate knee osteoarthritis under non-surgical management. Considering a statistical power of 80% and α = 0.05, the required sample size of 38 per group was estimated. After adding 20% to account for possible losses, the final sample size was set at 46 participants per group.
Silva MDC, Perriman DM, Fearon AM, Couldrick JM, Scarvell JM. Minimal important change and difference for knee osteoarthritis outcome measurement tools after non-surgical interventions: a systematic review. BMJOpen. 2023;13(5):e063026. Published 2023 May 18. doi:10.1136/bmjopen-2022-063026
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