Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment that delivers acoustic pressure waves through the skin to injured tissue, stimulating the body’s natural healing processes. Originally developed to break up kidney stones, it has been used for musculoskeletal conditions since the 1990s and has expanded into areas like wound healing and erectile dysfunction. The treatment requires no incision, no general anesthesia, and typically involves three to five sessions spaced a week apart.
How Shock Waves Trigger Healing
The “extracorporeal” part simply means “outside the body.” A handheld device pressed against your skin generates pressure waves that travel into the targeted tissue. These waves create a controlled micro-stress at the cellular level, which sets off a cascade of biological responses.
The key effect is neovascularization: the formation of new blood vessels in the treated area. When tissue is chronically injured, like a tendon that never fully healed, blood supply is often poor. Shock waves prompt immune cells called macrophages to release growth factors and signaling proteins that drive new blood vessel growth and tissue regeneration. In animal studies of Achilles tendon injuries, ESWT triggered the release of growth factors involved in tissue repair, including ones that stimulate collagen production and cell growth. The treatment also has anti-inflammatory effects, helping to reset the chronic inflammation cycle that keeps injuries from resolving on their own.
Focused vs. Radial: Two Types of Shock Wave
There are two main types of ESWT devices, and they work differently. Focused shock waves are generated inside the applicator and concentrated by a lens to reach a precise point deep in the tissue. Radial shock waves are produced by compressed air firing a small projectile inside a tube; the energy spreads outward from the tip of the device and loses intensity as it penetrates deeper.
In practical terms, focused ESWT delivers more energy to a specific target and reaches deeper structures. This matters for conditions like calcific tendonitis in the shoulder, where the tissue is thick enough that radial waves may not reach the problem area effectively. Radial ESWT works well for shallower targets like the plantar fascia on the bottom of the foot or superficial trigger points in muscles. Your provider will choose the type based on the location and depth of your condition.
Conditions It Treats
ESWT is used across a range of musculoskeletal problems, with the strongest evidence for chronic tendon injuries and bone healing issues. The most common indications include:
- Plantar fasciitis and heel pain: This is where ESWT has been most successful in routine clinical use.
- Achilles tendon pain: Both where the tendon inserts at the heel and in the mid-portion of the tendon.
- Calcific tendonitis of the shoulder: Shock waves can break up calcium deposits and promote their reabsorption.
- Tennis elbow (lateral epicondylitis): An established indication, though results tend to be less impressive than for heel or shoulder conditions.
- Delayed bone healing and non-unions: This was actually the oldest orthopedic use of ESWT, applied when fractures fail to heal on their normal timeline.
- Muscle trigger points: ESWT has gained ground in recent years for treating painful knots in muscles.
- Early-stage bone conditions: Including bone marrow edema and early osteonecrosis (bone tissue death from poor blood supply).
Beyond orthopedics, low-intensity shock wave therapy is also used for erectile dysfunction and chronic wound healing, though these applications use different energy levels and protocols.
Plantar Fasciitis Results
Plantar fasciitis is the condition with the most data behind ESWT. In a retrospective study of patients with chronic plantar fasciitis, average pain scores dropped from 6.9 out of 10 before treatment to 3.6 one month after the final session, and continued improving to 2.2 at three months and 0.9 at one year. The success rate, defined as more than 60% pain reduction, climbed from just 19% at one month to 70% at three months and 98% at one year.
That steep improvement curve is worth noting. ESWT is not a quick fix. The biological healing processes it triggers take weeks to months to fully develop, so patients who feel only modest relief at first often see substantial gains over the following months. The one-year recurrence rate in that study was 8%, and recurrence was more likely in patients who had longer pain duration before treatment and higher baseline pain levels.
Calcific Shoulder Tendonitis Results
For calcific tendonitis of the rotator cuff, ESWT can both relieve pain and break down the calcium deposits causing the problem. In a clinical trial comparing ultrasound-guided ESWT to standard landmark-based ESWT, complete resorption of calcium deposits at six months occurred in 66% of the ultrasound-guided group and 50% of the standard group. No patients in the ultrasound-guided group had zero resorption, while 15% in the standard group saw no change.
Shoulder function improved dramatically in both groups. Patients in the ultrasound-guided group saw their shoulder function scores nearly double, from a median of 50 out of 100 at baseline to 97 at six months. The standard group improved from 48 to 79. This suggests that having a provider use ultrasound imaging to aim the shock waves makes a meaningful difference for shoulder calcium deposits.
ESWT for Erectile Dysfunction
Low-intensity shock wave therapy (LiSWT) for erectile dysfunction uses much lower energy levels than orthopedic applications. The goal is the same: stimulating new blood vessel formation, this time in penile tissue, to improve blood flow.
The most common protocol delivers about 1,500 shock pulses per session across multiple sites, with treatments given once or twice weekly over 6 to 12 sessions. Multiple meta-analyses of randomized controlled trials have found statistically significant improvements in erectile function scores compared to sham treatment, with improvements in the range of 2 to 4 points on a standardized 25-point scale. That’s a modest but consistent effect, and some men who previously didn’t respond to oral medications found them effective after completing a course of LiSWT. Protocols vary between clinics, with some using up to 3,000 pulses per session over six consecutive weeks.
What a Session Feels Like
A typical session involves three to five treatments spaced about one week apart, though protocols vary by condition. Most sessions deliver between 1,000 and 2,500 impulses to the treatment area. While exact session duration isn’t standardized, most last roughly 10 to 20 minutes depending on the number of pulses and areas being treated.
The sensation is often described as a rapid tapping or pulsing against the skin. Higher energy settings produce more discomfort. Research confirms that pain during treatment increases in a dose-dependent way, meaning higher energy levels are more painful. Local anesthesia can reduce the discomfort, but there’s an important catch: studies have shown that numbing the area can actually block the therapeutic effects of low-energy ESWT. The shock waves appear to work partly by activating pain-sensing nerve fibers (C-fibers), and preventing that activation may undermine the treatment. For this reason, many providers avoid using local anesthesia, particularly for low-energy protocols.
Side Effects and Limitations
ESWT is generally well tolerated. The most common side effects are temporary and localized: redness, mild swelling, bruising, and soreness in the treated area. These typically resolve within a day or two. Serious complications are rare.
The treatment does have limitations. Not every condition responds equally well. Tennis elbow, for instance, has the weakest results among the standard orthopedic indications. Results also depend on factors like how long the condition has been present, with longer-standing problems sometimes being harder to treat. The gradual nature of improvement means it’s not suited for anyone expecting immediate relief, and some patients require additional sessions beyond the standard three to four. For conditions like plantar fasciitis, most patients receive three treatments, though about 10 to 20% need a fourth session to achieve adequate results.