physiotherapy treatment using radial shockwave therapy

Physiotherapy treatment using radial shockwave therapy has emerged as a cornerstone intervention for chronic musculoskeletal pathologies, offering a scientifically validated lifeline for patients who have exhausted traditional conservative management strategies. By harnessing the biological power of high-energy acoustic waves, this modality transitions injured tissue from a state of chronic degeneration into an active phase of regeneration, bridging the gap between standard rehabilitation and invasive surgical procedures.

This comprehensive report explores the physiological mechanisms, clinical indications, and evidence base supporting Radial Shockwave Therapy (RSWT), detailing how it integrates into a holistic recovery plan alongside manual therapy and exercise. Whether addressing the debilitating heel pain of plantar fasciitis or the persistent grip weakness of tennis elbow, physiotherapy treatment using radial shockwave therapy represents a paradigm shift in how clinicians approach the healing of recalcitrant soft tissue injuries.

The Evolution and Physics of Shockwave Therapy

To fully appreciate the clinical utility of Radial Shockwave Therapy (RSWT), it is essential to understand its origins and the physical principles that distinguish it from other therapeutic modalities. The technology traces its lineage back to the 1980s with the development of Extracorporeal Shockwave Lithotripsy (ESWL) in urology. Originally designed to disintegrate renal calculi (kidney stones) non-invasively, clinicians incidentally observed that the acoustic waves utilized in lithotripsy had profound effects on the surrounding musculoskeletal structures. Patients treated for kidney stones often reported the resolution of unrelated lower back pain or hip pathologies, sparking decades of research into the application of shockwaves for orthopaedic use.

While the original lithotripsy devices used focused high-energy waves, the evolution of the technology for physiotherapy led to the development of radial systems. Understanding the physics of these systems is paramount for distinguishing RSWT from other modalities often found in a physiotherapy clinic, such as ultrasound or electro therapy.

The Physics of Radial Pressure Waves

Radial shockwaves are technically described as "radial pressure waves." Unlike true focused shockwaves, which are generated via electromagnetic, electrohydraulic, or piezoelectric means and converge at a specific focal point deep within the body, radial waves are generated pneumatically. The mechanics of a radial device are ballistic in nature.

In a typical RSWT handpiece, compressed air accelerates a projectile (bullet) within a guiding tube. This projectile strikes a metal applicator at the tip of the handpiece with high kinetic energy. Upon impact, this kinetic energy is converted into acoustic energy—a pressure wave. This wave is transmitted into the patient’s tissue through a coupling gel.

The defining characteristic of the radial wave is its divergence. The point of highest pressure (energy density) is at the tip of the applicator—directly on the skin surface. As the wave travels deeper into the tissue, it spreads out radially, and the energy density diminishes. This makes RSWT particularly suited for treating superficial soft tissue conditions, myofascial trigger points, and tendinopathies where the pathology is located within 3 to 4 centimeters of the skin surface.

Radial vs. Focused Shockwave: A Technical Comparison

Confusion often exists regarding the difference between Radial (RSWT) and Focused (FSWT) shockwave therapy. While both induce mechanotransduction, their physical properties dictate their clinical applications.

For the majority of conditions treated in a standard musculoskeletal physiotherapy setting—such as plantar fasciitis, tennis elbow, and Achilles tendinopathy—RSWT is often the modality of choice due to its ability to treat the entire tendon-muscle unit rather than just a solitary point. However, physiotherapy treatment plans must be tailored to the individual; in cases of deep calcific tendonitis or osteonecrosis, focused systems may be preferable or used in conjunction with radial systems.

Biological Mechanisms: The Science of Healing

One of the most frequent questions regarding physiotherapy treatment using radial shockwave therapy is: "How does it actually work?" Unlike pharmacological interventions that mask symptoms, or electro therapy which often modulates nerve transmission, shockwave therapy is a regenerative treatment. It works by stimulating the body's intrinsic repair mechanisms through a process called mechanotransduction.

Mechanotransduction

Mechanotransduction is the process by which cells convert mechanical stimulus (the acoustic pressure wave) into biochemical activity. The cytoskeleton of the cell detects the mechanical strain caused by the shockwave, leading to changes in gene expression and protein synthesis. This is not a passive process; the shockwave essentially "wakes up" dormant cells in chronic injuries where the healing process has stalled (a state often referred to as "failed healing" or tendinosis).

Neovascularization

Chronic tendinopathies are often characterized by poor blood supply. The Achilles tendon and the supraspinatus tendon, for example, have "critical zones" of hypovascularity. Research has demonstrated that shockwave therapy induces the release of angiogenic growth factors, most notably Vascular Endothelial Growth Factor (VEGF) and Endothelial Nitric Oxide Synthase (eNOS). These factors stimulate neovascularization—the formation of new, healthy blood vessels. This increased blood supply brings vital oxygen and nutrients to the injured tissue, facilitating repair and removal of waste products.

Stimulation of Collagen Production

The structural integrity of tendons and ligaments depends on collagen. In chronic injury, collagen fibers become disorganized and structurally weak (changing from Type I to Type III collagen). RSWT stimulates fibroblasts—the cells responsible for connective tissue production—to synthesize new collagen fibers. Furthermore, the mechanical forces help to align these fibers along the lines of stress, restoring the tensile strength and elasticity of the tendon.

Dissolution of Calcified Fibroblasts

In conditions like calcific tendonitis of the shoulder, calcium deposits form within the tendon, causing impingement and severe pain. The high-energy acoustic waves of RSWT mechanically disrupt these calcifications. Once the calcium deposit is fragmented into smaller granular particles, the body’s lymphatic system can attack and reabsorb the calcium, effectively removing the obstruction. This mechanism is distinct from surgery, avoiding the need for invasive excision.

Pain Modulation and the Analgesic Effect

While the primary goal is tissue regeneration, RSWT also provides significant pain relief. This occurs through two primary mechanisms:

• Hyperstimulation Analgesia (Gate Control Theory): The intense mechanical stimulation of the shockwaves bombards the nervous system with sensory input. This intense input activates large-diameter sensory fibers, which inhibit the transmission of pain signals from the smaller C-fibers at the spinal cord level, effectively "closing the gate" to pain.
• Substance P Depletion: Substance P is a neurotransmitter involved in the transmission of pain and the regulation of inflammation. Studies suggest that shockwave therapy lowers the concentration of Substance P in the treated tissue, leading to a sustained reduction in pain sensitivity and neurogenic inflammation.

Conditions Treated and Clinical Evidence

The application of physiotherapy treatment using radial shockwave therapy is supported by a wealth of clinical literature and regulatory guidance. In the United Kingdom, the National Institute for Health and Care Excellence (NICE) has issued specific guidance (IPG) validating its use for several key conditions. This section details the primary indications and the evidence supporting them.

Plantar Fasciitis

Plantar fasciitis is the most common cause of heel pain, affecting approximately 10% of the population at some point in their lives. It involves degeneration of the plantar fascia origin at the medial calcaneal tubercle. When conservative measures like stretching, orthotics, and rest fail, RSWT is the gold standard for non-surgical management.

Evidence: The landmark study by Gerdesmeyer et al. (2008), published in the American Journal of Sports Medicine, demonstrated the efficacy of RSWT in chronic recalcitrant plantar fasciitis. The study reported a success rate of over 60% in the treatment group compared to placebo, with significant improvements in pain scores and functional outcomes. NICE guidance IPG311 specifically addresses this, noting that the evidence on efficacy is adequate to support its use, providing a safe alternative to surgery or corticosteroid injections, which carry risks of fat pad atrophy or fascia rupture.

Achilles Tendinopathy

Achilles tendinopathy is prevalent among runners and active individuals. It can present as Insertional (at the heel bone) or Mid-portion (in the tendon body). The pathology is often non-inflammatory (tendinosis), characterized by degenerative changes.

Evidence: Rompe et al. (2009) conducted a randomized controlled trial comparing eccentric loading exercises alone versus eccentric loading combined with shockwave therapy for mid-portion Achilles tendinopathy. The study found that the combined group had significantly better outcomes (VISA-A scores) than the exercise-only group. NICE guidance IPG571 confirms that RSWT is a viable option for refractory Achilles tendinopathy, particularly when combined with a loading program.

Lateral Epicondylitis (Tennis Elbow)

Lateral epicondylitis affects the common extensor origin at the elbow. It is notoriously difficult to treat due to the constant use of the hands and wrists in daily activities.

Evidence: Studies have shown that RSWT can effectively reduce pain and improve grip strength. NICE guidance IPG313 supports the use of shockwave for refractory tennis elbow. The analgesic effect is particularly beneficial here, allowing patients to engage in crucial strengthening exercises that would otherwise be too painful.

Greater Trochanteric Pain Syndrome (GTPS)

Historically diagnosed as "trochanteric bursitis," this condition is now understood to be largely a tendinopathy of the gluteus medius and minimus tendons. The widespread pain over the lateral hip makes the radial dispersion of RSWT an ideal treatment modality.

Evidence: Furia et al. (2009) demonstrated that RSWT was more effective than corticosteroid injections for GTPS in the long term. While steroids provided short-term relief, shockwave therapy offered superior sustained outcomes at 12 months, without the risk of tendon degradation associated with repeated steroid use.

Other Musculoskeletal Indications

• Patellar Tendinopathy (Jumper’s Knee): Highly effective for athletes involved in jumping sports (basketball, volleyball).
• Medial Tibial Stress Syndrome (Shin Splints): RSWT promotes periosteal healing and reduces inflammation along the tibia.
• Calcific Tendonitis of the Shoulder: Facilitates the resorption of calcium deposits and treats the associated tendinopathy.
• Myofascial Trigger Points: The acoustic waves can deactivate trigger points in the trapezius, quadratus lumborum, and other muscle groups, relieving tension headaches and chronic back pain.

Radial Shockwave vs. Electrotherapy and Ultrasound

Patients often confuse shockwave therapy with other modalities. It is crucial to clarify that physiotherapy treatment using radial shockwave therapy is distinct from electro therapy and therapeutic ultrasound.

Comparison with Electrotherapy (TENS)

Electro therapy, particularly Transcutaneous Electrical Nerve Stimulation (TENS), involves applying electrical currents to the skin. The primary mechanism of TENS is neuromodulation—distracting the brain from pain signals (pain masking). It does not repair tissue. It is often a temporary fix. In contrast, RSWT is a mechanical treatment that induces structural tissue repair. While "electro threrapy" (a common misspelling for electrotherapy) might be used for symptom management, it does not offer the regenerative capacity of shockwaves.

Comparison with Therapeutic Ultrasound

Therapeutic ultrasound uses high-frequency sound waves to generate thermal (heat) or non-thermal effects. While it can increase blood flow and tissue extensibility, the energy levels are significantly lower than shockwave therapy. Shockwave delivers high-energy pulses that create "micro-trauma," a potent stimulus required to restart the healing process in chronic, stagnant tissues (chronic tendinosis) where the body has stopped trying to heal itself. Ultrasound is generally too gentle to provoke this response in chronic fibrotic tissue.

The Clinical Procedure: What Patients Can Expect

A course of physiotherapy treatment using radial shockwave therapy follows a structured clinical pathway to ensure safety and efficacy.

Assessment and Suitability

Before the first shock is delivered, a comprehensive physiotherapy assessment is mandatory. This includes taking a detailed history to identify the chronicity of the injury (usually present for >3 months) and screening for contraindications. Ultrasound imaging may be used to confirm the diagnosis and locate calcifications.

Contraindications

Safety is paramount. RSWT is not suitable for:

• Pregnancy: If the treatment area is near the fetus.
• Blood Clotting Disorders: Including patients on high-dose anticoagulants (e.g., Warfarin), due to the risk of hematoma.
• Active Malignancy: Cancer in the treatment area.
• Acute Inflammation/Infection: RSWT is for chronic conditions; treating acute, swollen, or infected tissue can exacerbate the issue.
• Corticosteroid Injection: It is standard protocol to wait at least 6 weeks (and often up to 12 weeks) after a steroid injection before starting shockwave, as steroids weaken the tendon and increase rupture risk under mechanical load.
• Lung Tissue: Shockwaves are never applied over the chest wall/lungs due to the risk of damage to the alveoli.

The Treatment Protocol

A typical session proceeds as follows:

1. Positioning: The patient is positioned comfortably to expose the treatment area.
2. Mapping: The clinician uses palpation to identify the area of maximal tenderness.
3. Coupling: Ultrasound gel is applied to the skin to ensure acoustic transmission.
4. Application: The radial applicator is placed on the skin. The machine is set to the appropriate frequency (Hz) and pressure (Bar). Typical settings for plantar fasciitis might be 2.5 Bar at 10-15 Hz.
5. Dose: A standard treatment delivers between 2000 and 3000 shocks (impulses). This takes approximately 3 to 5 minutes.
6. Sensation: The patient feels a loud tapping or hammering sensation. It can be uncomfortable but is usually tolerable. The therapist will often start at a lower intensity and ramp up ("biofeedback") as the patient tolerates it.

Course of Treatment

Evidence suggests that a single session is rarely sufficient for chronic conditions. The standard protocol involves 3 to 6 sessions, spaced 5 to 10 days apart (typically weekly). This interval allows the immediate inflammatory response to subside and the regenerative process to initiate before the next stimulus.

Post-Treatment Advice

Post-treatment care is critical for success. Patients are advised:

• Relative Rest: Avoid high-impact loading (running, jumping) for 48 hours after treatment.
• No Ice or Anti-inflammatories: Do not take NSAIDs (Ibuprofen, Naproxen) or ice the area for 24-48 hours. The treatment works by inducing a controlled inflammatory response; suppressing this with drugs or ice can negate the therapeutic effect. Paracetamol is acceptable for pain relief.
• Exercise: Continue with prescribed low-load rehabilitation exercises as guided by the physiotherapist.

Integration with Rehabilitation

It is a fundamental principle of physiotherapy that "passive treatments alone rarely cure chronic problems." Physiotherapy treatment using radial shockwave therapy is most effective when used as part of a comprehensive rehabilitation program. Shockwave therapy creates the biological environment for healing (reducing pain, stimulating cells), but mechanical loading (exercise) provides the signal for the new tissue to become strong and functional.

For example, in Achilles tendinopathy, shockwave therapy reduces pain, allowing the patient to perform eccentric or heavy slow resistance protocols. This combination addresses both the biological degeneration and the biomechanical weakness, leading to superior long-term outcomes compared to either treatment in isolation.

Conclusion

Physiotherapy treatment using radial shockwave therapy represents a significant advancement in the non-surgical management of chronic musculoskeletal disorders. By leveraging the principles of mechanotransduction, this modality offers a scientifically proven method to reactivate healing in tissues that have become unresponsive to conventional care. Its ability to stimulate neovascularization, promote collagen synthesis, and provide potent analgesia makes it an invaluable tool for both the general population and elite athletes alike.

While not a "magic bullet," when combined with expert clinical reasoning and a structured rehabilitation program, RSWT offers high success rates for stubborn conditions like plantar fasciitis and tendinopathies. For patients seeking to avoid the risks of surgery or the side effects of steroid injections, physiotherapy treatment using radial shockwave therapy stands out as a safe, effective, and evidence-based pathway to recovery.