What are the indications for transcutaneous electrical nerve stimulation (TENS), short‑wave diathermy (SWD), and interferential therapy (IFT) in adult patients?

Indications for TENS, SWD, and IFT in Adult Patients

Transcutaneous Electrical Nerve Stimulation (TENS)

TENS should only be used as part of multimodal pain management for chronic low back pain, not as standalone therapy, and has insufficient evidence for most other musculoskeletal conditions. 1

Evidence-Based Indications

• Chronic low back pain: TENS may be used only when combined with exercise, physical therapy, and medications—never as monotherapy 1
• Cancer-related chronic pain: May be considered as adjunctive therapy, though evidence from only 88 patients across three trials showed no significant benefit over control groups 1
• Myofascial pain in cancer survivors: Can be considered as part of comprehensive pain management 2, 3

Conditions Where TENS is NOT Recommended

• Acute or subacute low back pain: Insufficient evidence to support use 1
• Knee or hip osteoarthritis: Strongly recommended against by the American College of Rheumatology due to lack of demonstrated benefit 4
• Muscle tightness relief: No evidence supports this indication 4

Clinical Algorithm for TENS Use

1. First-line therapies must fail first: Conventional medications and physical therapy should be attempted before considering TENS 4, 3
2. Only for chronic conditions: Do not use for acute pain (duration <3 months) 1, 4
3. Require multimodal approach: Must combine with exercise therapy, physical therapy, and appropriate analgesics 1, 4
4. Trial period required: Document pain reduction and functional improvement before continuing therapy 3

Important Caveats

• Approximately one-third of patients experience mild skin irritation at electrode sites 1, 4, 2
• One Cochrane review found TENS no better than sham treatment in the largest, highest-quality trial for chronic low back pain 1
• Evidence quality is consistently low across all studied conditions 1, 4, 3

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Short-Wave Diathermy (SWD)

Short-wave diathermy has minimal evidence supporting its use, with only thermal (not athermal) SWD showing small benefits for chronic knee osteoarthritis. 1, 5

Limited Evidence-Based Indications

• Chronic knee osteoarthritis: Only thermal SWD (producing local heat sensation) showed small pain reduction benefits; athermal/pulsed SWD was ineffective 5
• Chronic osteoarthritis (general): Continuous SWD rated as potentially effective by clinicians, though controlled trial evidence is lacking 6
• Chronic polyarthritis and non-specific arthrosis: Clinician-reported effectiveness for continuous SWD, but no high-quality trial evidence 6

Conditions with Insufficient Evidence

• Acute low back pain: One small trial (24 patients) found SWD inferior to spinal manipulation 1
• Chronic low back pain: Two trials showed no differences between SWD and sham treatment or other interventions 1
• Acute soft tissue injuries: Pulsed SWD reported as effective by clinicians, but lacks controlled trial validation 6
• Haematomas, sinusitis, rheumatoid arthritis: Clinician-reported effectiveness without supporting trial evidence 6

Clinical Algorithm for SWD Use

1. Consider only for chronic knee osteoarthritis: Use thermal SWD (producing warmth sensation) as adjunct to other therapies 5
2. Avoid for acute conditions: No evidence supports use in acute pain or injury 1
3. Do not use athermal/pulsed SWD for pain: Meta-analysis showed no benefit when thermal effect absent 5
4. Require adequate dosing: Studies showing benefit used sufficient power to produce local thermal sensation 5

Critical Safety Concerns

• Operator safety practices are inadequate: 30% of surveyed physiotherapists reported taking no operator safety measures 6
• Distance requirements ignored: Only 5 of surveyed respondents maintained specified distance from equipment during operation 6
• Lack of comprehensive safety guidelines: Urgent need for standardized protocols to protect operators, patients, and nearby personnel 6

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Interferential Therapy (IFT)

Interferential current shows the most promising evidence among these three modalities, with recent network meta-analysis demonstrating superior pain reduction and functional improvement for chronic low back pain. 7

Evidence-Based Indications

• Chronic low back pain: IFT demonstrated greatest pain reduction (SMD -0.96) and functional improvement (ODI reduction -7.28, RMDQ reduction -3.13) compared to controls in 2025 network meta-analysis 7
• Non-specific low back pain: Equal analgesic efficacy to TENS in direct comparison trial 8

Clinical Algorithm for IFT Use

1. First-line consideration for chronic low back pain: IFT ranked highest by P-score across pain and functional outcomes 7
2. Preferred over TENS for chronic conditions: Network meta-analysis shows IFT more effective than low-frequency TENS 7
3. Use as part of comprehensive management: Combine with exercise therapy and appropriate medications 7
4. Treatment duration: Studies showing benefit used series of 10-20 minute sessions 8

Evidence Quality Considerations

• The 2025 network meta-analysis provides the most recent and comprehensive evidence, though certainty of evidence remains low 7
• Direct comparison studies show IFT and TENS have similar analgesic effects, but network analysis suggests IFT superiority 7, 8
• No systematic reviews exist specifically for IFT, limiting comprehensive assessment 1

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Comparative Effectiveness Summary

Based on the most recent high-quality evidence, IFT demonstrates superior efficacy to both TENS and SWD for chronic low back pain. 7

Ranking by Evidence Quality (Chronic Low Back Pain)

1. IFT: Strongest evidence with greatest pain reduction and functional improvement 7
2. High-frequency TENS: Significant pain reduction (SMD -0.81) but inferior to IFT 7
3. Low-frequency TENS: Non-significant effect on pain 7
4. SWD: No demonstrated benefit for low back pain 1

Common Pitfalls to Avoid

• Using any modality as monotherapy: All three require integration into multimodal pain management programs 1, 4
• Applying to acute conditions without evidence: TENS and SWD lack support for acute pain management 1, 4
• Ignoring safety protocols for SWD: Operator and bystander safety measures are frequently neglected 6
• Expecting large treatment effects: Even when effective, these modalities produce small to moderate benefits 7, 5
• Using athermal SWD for pain: Only thermal SWD shows any benefit 5