Ultrasound Therapy for Joints: Does It Help Arthritis?

Key Takeaways

• Therapeutic ultrasound uses sound waves to treat soft tissue and joint conditions
• Evidence for arthritis is mixed—some studies show benefit, others don’t
• Generally safe with minimal side effects
• Often used as part of physical therapy sessions
• May help more for muscle and tendon issues than joint arthritis
• Usually covered by insurance when part of PT treatment

If you’ve had physical therapy, you may have experienced therapeutic ultrasound—a wand moved over your skin while warm gel transmits sound waves into your tissues. But does this common treatment actually help joint pain?

What Is Therapeutic Ultrasound?

The Basics

Therapeutic ultrasound uses high-frequency sound waves (above human hearing range) directed into body tissues. Unlike diagnostic ultrasound that creates images, therapeutic ultrasound aims to create beneficial effects in tissues.

How It Works

Sound waves passing through tissue create two types of effects:

Thermal effects:

• Sound waves cause tissue molecules to vibrate
• Vibration creates friction and heat
• Deep heating may improve circulation
• May increase tissue extensibility

Non-thermal effects:

• Cavitation (microscopic bubbles forming and collapsing)
• Streaming (movement of fluids around cells)
• May stimulate cellular activity
• May promote healing

Treatment Parameters

Frequency:

• 1 MHz: Deeper penetration (3-5 cm)
• 3 MHz: Shallower (1-2 cm)
• Choice depends on target depth

Intensity:

• Measured in watts per square centimeter (W/cm²)
• Range typically 0.5-2.0 W/cm²
• Higher isn’t always better

Mode:

• Continuous: More thermal effect
• Pulsed: Less heat, more mechanical effects

Duration:

• Usually 5-10 minutes per area
• Part of overall PT session

What Does Research Show?

For Knee Osteoarthritis

Evidence summary:

• Results are inconsistent
• Some studies show modest benefit
• Others show no difference from placebo (sham ultrasound)
• Cochrane review found insufficient evidence

2024 assessment:

• Not recommended as standalone treatment
• May have small benefit as part of comprehensive PT
• Not a primary treatment option

For Soft Tissue Conditions

Where it may help:

• Tendinopathies (some evidence)
• Soft tissue injuries
• Scar tissue management
• Muscle spasm

Better evidence for:

• Lateral epicondylitis (tennis elbow)—mixed but some positive
• Calcific shoulder tendinitis
• Myofascial trigger points

For Rheumatoid Arthritis

• Limited studies
• Not well-established
• Not typically recommended

Honest Assessment

The challenge:

• Hard to do placebo-controlled studies (patients feel the warmth)
• Treatment parameters vary widely
• May work better for some conditions than others
• Often used in combination with other treatments

Bottom line:

• Probably provides modest benefit for some patients
• Unlikely to be transformative as standalone treatment
• Safe enough that trying it as part of PT is reasonable
• Shouldn’t be sole treatment for arthritis

The Treatment Experience

What to Expect

Preparation:

• Area exposed and cleaned
• Conductive gel applied
• No special preparation needed

During treatment:

• Transducer (wand) moved in circles over treatment area
• You may feel mild warmth
• Should NOT feel pain or burning
• Tell therapist if uncomfortable

After treatment:

• Gel cleaned off
• May proceed to other PT exercises/treatments
• No downtime

Settings You Might Receive

For deep tissue (knee joint):

• 1 MHz frequency
• Continuous or pulsed mode
• Moderate intensity
• 5-10 minutes

For superficial tissue:

• 3 MHz frequency
• May be lower intensity
• Shorter duration

How It Fits in Physical Therapy

Common Treatment Sequence

Typical PT session might include:

1. Hot pack or ultrasound (warming/preparation)
2. Manual therapy (stretching, mobilization)
3. Therapeutic exercises
4. Ice if needed

Why Therapists Use It

Practical reasons:

• Prepares tissue for manual therapy
• Part of traditional PT toolkit
• Patients often expect/request it
• Minimal effort to administer

Potential benefits:

• May enhance other treatments
• Provides hands-on time
• Warming effect appreciated
• Low risk

The Debate in PT

Many evidence-based physical therapists have moved away from extensive use of “passive modalities” like ultrasound in favor of:

• Exercise
• Manual therapy
• Active patient participation

Some argue ultrasound time could be better spent on exercises.

When It Might Help

Potentially Useful For

• Preparing tissues before stretching
• Reducing muscle guarding
• Part of multimodal approach
• When heat is beneficial but deep

Probably Not Useful For

• Primary treatment for knee OA
• Bone-on-bone arthritis
• Standalone treatment for any condition
• Patients expecting significant improvement from US alone

Consider the Context

Reasonable uses:

• Brief application as part of comprehensive PT
• When patient responds well to heat
• Preparing tight tissues for exercise

Question the use if:

• Majority of PT time spent on passive treatments
• No exercise component to sessions
• Used as sole intervention
• Excessive number of sessions focused on modalities

Comparing to Other Modalities

Heat Modalities

Treatment	Depth	Evidence	Cost
Hot pack	Superficial	Symptom relief	Low
Ultrasound	Deep	Mixed	Moderate
Diathermy	Deep	Limited	Higher

All Serve Similar Purpose

Different methods of applying heat:

• Hot packs: Convenient, superficial
• Ultrasound: Deeper, requires equipment
• Whirlpool: Combines heat and water

Choice often based on:

• Therapist preference
• Available equipment
• Patient response
• Treatment goals

Cost and Insurance

Typical Costs

As part of PT:

• Included in PT session fee
• Individual session: $50-$150
• Usually covered by insurance as part of PT

Standalone (rare):

• Not typically offered alone
• Would be low cost if separate

Insurance Considerations

• Usually covered as part of comprehensive PT
• Some insurers limiting passive modality coverage
• Check your specific plan
• Medicare covers PT but may have restrictions

Home Ultrasound Devices

What’s Available

Some home ultrasound devices are marketed for pain relief:

• Lower intensity than professional
• Variable quality
• FDA-cleared devices available
• Prices range from $50-$300

Considerations

Potential benefits:

• Convenience
• Self-administered
• One-time cost

Concerns:

• Limited evidence for home use
• Lower power than professional
• Risk of improper use
• Probably limited benefit for arthritis

Recommendation:

• If interested, discuss with your PT
• May be reasonable for specific conditions
• Don’t expect dramatic results
• Follow all safety guidelines

Safety and Precautions

Generally Safe When

• Performed by trained professional
• Appropriate settings used
• Patient communicates any discomfort
• Contraindications observed

Contraindications

Do not use over:

• Malignancy (cancer sites)
• Pregnancy (over uterus)
• Growth plates in children
• Metal implants (caution)
• Infected tissue
• Areas with impaired sensation
• Thrombophlebitis
• Eyes, heart, reproductive organs

Possible Side Effects

• Mild warmth (expected)
• Temporary skin redness
• Burns if misused (rare with proper technique)

Questions to Ask Your Therapist

About Treatment

1. Why are you recommending ultrasound for me?
2. What do you expect it to accomplish?
3. How does it fit into my overall treatment plan?
4. What’s the evidence for ultrasound for my condition?

About Your PT Plan

1. What percentage of my sessions will be exercise vs. modalities?
2. What are my goals and how will we measure progress?
3. How many sessions do you anticipate?
4. What should I be doing at home?

Frequently Asked Questions

Does ultrasound actually penetrate to the joint?

At 1 MHz frequency, ultrasound can penetrate 3-5 cm, which can reach many joints. However, whether this penetration translates to therapeutic benefit for joint conditions specifically is not well-established.

Why do some therapists not use ultrasound?

Evidence-based practice has evolved toward emphasizing active treatments (exercise, movement) over passive modalities. Many therapists feel time spent on ultrasound could be better used for exercises that have stronger evidence of benefit.

Can I feel the ultrasound working?

You typically feel mild warmth. This is normal. You should NOT feel pain or burning. The warmth indicates thermal effects, but feeling warmth doesn’t guarantee therapeutic benefit—it just means sound waves are generating heat.

Is diagnostic ultrasound the same as therapeutic?

No. Diagnostic ultrasound (like pregnancy ultrasounds) uses lower intensity to create images. Therapeutic ultrasound uses higher intensity to create thermal and mechanical effects in tissue. The machines are different.

If the evidence is mixed, why is it still used?

Several reasons: it has a long history in PT, it’s low-risk, some patients respond well, it’s often combined with other treatments (making it hard to know what’s helping), and the ritual of hands-on treatment may have value.

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Exploring physical therapy options? Read about physical therapy for knee osteoarthritis or learn about TENS units for pain management.

Last medically reviewed: February 2025

Medical Disclaimer: This article is for informational purposes only. Discuss treatment options with your physical therapist and healthcare provider to determine the best approach for your specific condition.