Effects of Including Interferential Current in a Therapeutic Exercise Program in Individuals With Knee Osteoarthritis

Overview

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.

Detailed description

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

Interventions

• Other Therapeutic Exercise
  The therapeutic exercise program includes a warm-up, resistance, neuromuscular, mobility, and balance exercises.
• Device Interferential Current
  However, the interferential current will be applied at the end of the therapeutic exercises. In this way, the IC will be used through a device (Endophasys® - NMS-0501, KLD Biosistemas® Equipamentos Eletrônicos Ltda). Four electrodes (8x5 cm), two upper and two lower (forming a square), will be positioned around the center of the knee. The parameters used were as follows: carrier current frequency of 4000 Hz; amplitude modulated frequency of 50 Hz; sweep frequency of 50 Hz; oscillation pattern of
• Device placebo interferential current
  However, the interferential current will be applied at the end of the therapeutic exercises. In this way, the IC will be used through a device (Endophasys® - NMS-0501, KLD Biosistemas® Equipamentos Eletrônicos Ltda). Four electrodes (8x5 cm), two upper and two lower (forming a square), will be positioned around the center of the knee. The parameters used were as follows: carrier current frequency of 4000 Hz; amplitude modulated frequency of 50 Hz; sweep frequency of 50 Hz; oscillation pattern of

Primary outcome measures

• Reported pain [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]

Secondary outcome measures (7)

• Numerical Pain Scale [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Functional disability [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Functional self-perception [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Functional capacity [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Inability [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Maximum voluntary isometric contraction [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]
• Global Perception of Change scale [Time frame: before the first treatment session, after 8 weeks of treatment and 4 weeks after the end of the last session]

Eligibility criteria

Inclusion criteria

• both sexes
• between 40 years old and 75 years old
• with a clinical diagnosis of unilateral KOA
• Who has had 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
• Crepitus
• Bone tenderness and absence of palpable heat

Exclusion criteria

• Hip OA
• Severe osteoporosis
• Fibromyalgia
• Clinical history of tumors or cancer
• Active inflammatory joint diseases (rheumatoid arthritis, gout)
• Undergoing any joint replacement in the lower extremity
• Neurological diseases (Parkinson's disease, stroke
• Multiple sclerosis
• muscular dystrophies
• Diseases involving motor neurons
• Alzheimer's disease
• Infected wounds or osteomyelitis in the knee region
• Deep vein thrombosis or thrombophlebitis
• Sensory alteration in the lower limbs
• Cognitive and cardiopulmonary impairment that may prevent or limit the execution of exercises
• Use of a walking assistance device
• History of recent knee trauma
• Having undergone any form of treatment involving physical therapy
• intra-articular corticosteroids
• anti-inflammatory drugs
• opioid medication or chondroprotective in the six months before the start of the interventions

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Brazil · 1 center

• University of Nove de Julho — São Paulo

Identifiers

NCT: NCT06744036 · 7.267.733

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗