Shockwave therapy has a meaningful clinical evidence base for adhesive capsulitis. Randomized trials and meta-analyses report improvements in pain, shoulder function and range of motion, particularly when ESWT is used alongside rehabilitation. A 2025 sham-controlled trial found that radial ESWT added to the same evidence-based physical therapy program produced substantially greater improvements in pain and disability at 12 weeks. The evidence is still heterogeneous, protocols vary, and ESWT does not replace mobility or rehabilitation. Frozen shoulder also has established medical options such as corticosteroid injection, whose best-supported benefit is faster short-term relief, so treatment selection should reflect the stage, irritability and individual presentation.
What has shockwave been studied for in the shoulder?
The trials below enrolled people with adhesive capsulitis: a painful shoulder with restricted active and passive glenohumeral motion, often especially in external rotation. Frozen shoulder is a fibroinflammatory disorder of the joint capsule, which is different from rotator cuff tendinopathy or calcific tendinitis, conditions that have their own shockwave research. The distinction is covered in frozen shoulder vs. rotator cuff pain, and rotator cuff presentations on rotator cuff and shoulder pain.
Why frozen shoulder is a different target
Frozen shoulder is one of the few musculoskeletal conditions where fibrosis is well documented in human tissue. Capsule biopsies have shown active fibroblasts, new type III collagen deposition and increased signaling molecules such as TGF-beta and PDGF (Rodeo, 1997). Surgical studies of refractory cases describe contracture of the coracohumeral ligament and rotator interval (Ozaki, 1989). Modern biopsy work confirms that frozen-shoulder capsule fibroblasts show an activated inflammatory and fibrotic phenotype (Akbar, 2019), and a 2021 review of 25 studies described chronic inflammation, fibroblast proliferation and reduced matrix-degrading enzyme activity (Jump, 2021).
That biology explains why the shoulder stiffens. It does not mean shockwave has been shown to reverse it. The clinical trials below measure pain, function and motion.
The key studies at a glance
| Study | Design | Comparison | Main finding | Key limitation |
|---|---|---|---|---|
| Sharahili 2025 | RCT, 30 patients | Radial ESWT + PT vs. sham + same PT | 12-week pain −3.33; DASH −24.70 | Small trial |
| Zhang 2022 | Meta-analysis, 20 studies | Adjunct ESWT vs. routine care | Pain, function and external rotation favored ESWT | Range of motion I² 93% |
| El Naggar 2020 | RCT, 103 diabetic patients | Radial ESWT vs. low-dose steroid injection | 12-week qDASH 40.4 vs. 50.5; pain 1.6 vs. 2.8 | Diabetic population; low-dose comparator |
| Chen 2014 | RCT, 40 patients | ESWT vs. oral steroid | Both improved; several short-term measures favored ESWT | Small; short-term |
| Reno 2025 | Review, 7 studies, 352 diabetic patients | ESWT vs. conservative care | Substantial pain improvement | Low study quality |
What did the 2025 sham-controlled trial find?
Sharahili and Alzahrani randomized 30 people with adhesive capsulitis, published in the Saudi Medical Journal in 2025. Both groups received the same evidence-based physical therapy program over six weeks. One group also received radial ESWT; the other received sham shockwave.
In a 2025 randomized sham-controlled trial, adding radial ESWT to the same evidence-based physical therapy program improved pain by an additional 3.33 points and disability by 24.7 DASH points at 12 weeks. Pain was also lower immediately after the treatment period (by 2.00 points). Active flexion, abduction and internal rotation were better at 12 weeks, and external rotation was better both immediately and at 12 weeks. Passive abduction and external rotation also favored the shockwave group.
Because both groups did the same therapy, this design isolates the added effect of shockwave. With only 30 participants, it is a strong signal rather than definitive proof.
What do the meta-analyses show?
Zhang 2022. A meta-analysis of 20 studies in the Orthopaedic Journal of Sports Medicine compared ESWT added to other treatments with those treatments alone.
- Immediate pain: lower with ESWT (mean difference −1.10 points)
- Short-term pain: lower with ESWT (−0.72 points)
- Immediate function: better with ESWT (standardized mean difference 1.54), with consistent results across studies
- External rotation: about 10 degrees more (10.31°), but heterogeneity was very high (I² 93%)
- Longer-term pain: favored ESWT, also with high heterogeneity (I² 89%)
A 20-study meta-analysis found better short-term pain, function and external rotation with adjunctive ESWT, although the range-of-motion and longer-term analyses were highly heterogeneous. The authors concluded ESWT could be used as an adjunct to routine treatment.
Network evidence. A 2021 network meta-analysis of 92 trials and 5,946 patients compared 32 nonsurgical treatments. Shockwave ranked highest for functional improvement, alongside established options such as steroid injection and capsular distension, which both improved pain and function compared with placebo.
Shockwave compared with steroids
Radial ESWT vs. steroid injection in diabetes. El Naggar and colleagues randomized 103 diabetic patients with adhesive capsulitis to four weekly sessions of radial ESWT or a single ultrasound-guided low-dose injection of 20 mg triamcinolone, published in the Journal of Shoulder and Elbow Surgery in 2020. In 103 diabetic patients, radial ESWT produced better 12-week pain and qDASH scores than a low-dose ultrasound-guided steroid injection (qDASH 40.4 vs. 50.5; pain 1.6 vs. 2.8), while range-of-motion improvement was similar. That result applies to a diabetic population and a low-dose comparator, so it does not show shockwave is better than steroid injection in general.
ESWT vs. oral steroids. An earlier 40-patient randomized trial (Chen, 2014) found both oral steroids and ESWT improved outcomes, with several short-term functional and range-of-motion measures favoring ESWT. Side effects of ESWT were transient.
Corticosteroid Injection: Faster Relief, but What Happens Long Term?
Corticosteroid injection can accelerate symptom improvement in frozen shoulder, particularly during the early pain-dominant phase. The more important limitation is durability: randomized trials have repeatedly shown that the early advantage diminishes with time. Because a locally injected glucocorticoid still produces systemic exposure and has dose- and frequency-dependent biological effects, the decision involves more than short-term pain relief.
| Best-supported advantage | Faster short-term pain and disability improvement |
|---|---|
| Long-term advantage | Not consistently demonstrated; randomized frozen-shoulder trials converge by longer follow-up |
| Important tradeoffs | Systemic absorption, transient hyperglycemia, effects on cortisol production, cumulative-exposure concerns, and timing considerations if shoulder surgery may be needed |
Short-term benefit, 12-month convergence
Carette and colleagues randomized 93 patients to a steroid injection with supervised physiotherapy, a steroid injection alone, saline with physiotherapy, or saline alone, published in Arthritis and Rheumatism in 2003. At six weeks, both steroid groups had improved significantly more on the SPADI pain and disability score, and at three months they were still ahead of placebo. In a 93-patient placebo-controlled trial, corticosteroid injection accelerated early improvement, but by 12 months all treatment groups had improved to a similar degree. In other words, the injection changed the speed of symptom improvement more clearly than the eventual long-term outcome.
A second randomized primary-care trial found the same general pattern (Sharma, 2016). Steroid injections, with or without capsular distension, produced large improvements over usual care at four to eight weeks, but the long-term difference disappeared by 12 months.
Does a higher dose work better?
More steroid does not appear to produce a better frozen-shoulder result. A 2023 meta-analysis of four studies and 274 patients found no significant advantage from higher-dose steroid for pain, motion or function, at three weeks, six weeks or one year (Kim, 2023). The authors recommended starting with lower doses when steroid is chosen, because increasing exposure did not improve outcomes.
A shoulder injection still produces systemic steroid exposure
"Local" does not mean that glucocorticoid exposure remains confined to the shoulder. Intra-articular corticosteroids are systemically absorbed, and measurable systemic effects can persist for weeks. A 2019 review described associated complications including hyperglycemia, infection, loss of bone density and Cushing syndrome, while noting substantial individual variability (Stout, 2019). Cumulative dose and repeated injections matter, along with the type and dose of steroid and any concurrent oral steroids. Not every patient experiences clinically important systemic effects, but the exposure is real.
Cortisol production. Intra-articular corticosteroid exposure can transiently suppress the hypothalamic-pituitary-adrenal axis. The magnitude varies by dose, preparation and injection site. In a 2022 meta-analysis of prospective studies, spinal injections were the main concern, while average morning cortisol after injections in the limbs and peripheral joints suggested normal adrenal function was likely maintained, and the authors did not recommend limiting those injections on this basis (Whelan, 2022). The effect still reinforces that a joint injection is not purely local.
Blood glucose. In an adhesive-capsulitis-specific study of 78 patients, fasting glucose rose during the first week after intra-articular glucocorticoid injection and the increase was greater in patients with diabetes (Akin-Takmaz, 2021). Levels returned toward baseline by approximately two weeks, and the authors considered injection reasonable in well-controlled diabetes. A systematic review of diabetic patients found a post-injection rise in glucose in every included study (7 studies, 72 patients). Some individuals experienced marked excursions, with reported peaks as high as 500 mg/dL, usually within 24 to 72 hours (Choudhry, 2016). That represents a possible extreme response, not the expected response for every patient.
What do we know about repeated corticosteroid exposure and shoulder tissue?
Basic-science shoulder research raises an additional concern about cumulative exposure. Corticosteroids can reduce tendon-cell viability, alter collagen and extracellular-matrix biology and temporarily reduce mechanical properties. These effects appear dose- and frequency-dependent, and in laboratory studies they were often transient after isolated exposure (Puzzitiello, basic science review, 2020). These studies largely involve rotator cuff tissue and laboratory or animal models. They do not prove that a single glenohumeral injection for frozen shoulder permanently damages the shoulder.
Clinical shoulder literature also suggests that repeated corticosteroid exposure and timing can matter. In rotator cuff populations, preoperative injections have been associated with higher revision and infection risk, with stronger associations for repeated injections and injections closer to surgery (Puzzitiello, clinical review, 2020). These findings come from rotator cuff surgical populations rather than isolated frozen shoulder, so they should not be interpreted as direct proof of long-term harm from one glenohumeral injection.
Timing also matters when surgery is anticipated. In a shoulder-arthroplasty systematic review of 87,820 patients, the overall effect of any prior injection was not clearly significant, but injections within three months of arthroplasty were associated with higher infection risk (Chowdhury, 2024). Most people with frozen shoulder never need shoulder replacement; the point is that steroid exposure is relevant if shoulder surgery is being considered.
Broader intra-articular literature also demonstrates dose- and time-dependent corticosteroid effects on chondrocyte and cartilage biology, with low doses neutral or even beneficial in some models and higher or cumulative doses associated with chondrocyte toxicity (Wernecke, 2015). Much of that evidence is experimental or comes from joints other than the shoulder, so it supports caution with cumulative exposure rather than proving that one frozen-shoulder injection causes cartilage damage.
How this compares with shockwave
ESWT avoids glucocorticoid exposure. That is a meaningful distinction, particularly for patients in whom glucose control, repeated steroid exposure or future surgical considerations matter. Whether ESWT is the better choice still depends on diagnosis, irritability, stage, rehabilitation history and patient preferences. Shockwave has its own limits, including small trials, varied protocols and transient treatment discomfort, and a single appropriately selected steroid injection can still be reasonable.
What did the treatment involve?
Protocols differ between studies, which is one reason results vary. The diabetic steroid comparison used four radial sessions one week apart. The 2025 sham-controlled trial delivered radial shockwave alongside a six-week physical therapy program. Treatment energy, number of impulses, applicator position and session count are not standardized across the literature, and review authors have called for trials that establish best-practice protocols. The parameters in a study describe what was tested, not a fixed prescription for every shoulder.
How quickly did patients improve?
In the 40-patient oral steroid comparison, Constant Shoulder Score and range-of-motion measures improved from about the fourth week in the shockwave group. In the 2025 trial, pain was already lower than with sham immediately after the six-week treatment period, and the gap was larger at 12 weeks. Most studies report short- to medium-term outcomes, so long-term comparative data are more limited.
Why diabetes matters
Adhesive capsulitis is more common in people with diabetes. Several shockwave studies have focused on this group. A 2025 review of seven studies and 352 patients with type 2 diabetes found substantial pain improvement with ESWT (Reno, 2025), but the authors emphasized study-quality limitations and called for better trials. The reported pain change was within the treated groups, not the difference from a control group. Diabetic results should not be assumed to apply with the same effect size to everyone, and shockwave is not limited to diabetic patients.
Is radial or focused shockwave better for frozen shoulder?
Radial ESWT has direct randomized adhesive-capsulitis evidence, including the 2025 sham-controlled trial and the diabetic steroid comparison. Focused ESWT may also be considered clinically, but current evidence does not establish focused treatment as universally superior. A deeper target does not automatically make focused treatment better. The choice depends on the examination and the presentation. For the broader comparison, see radial vs. focused shockwave.
How does shockwave fit with other frozen shoulder treatments?
- Mobility and exercise: foundational. A 2022 systematic review found exercise therapy improves range of motion, function and pain, and intensity is matched to how irritable the shoulder is.
- Corticosteroid injection: can accelerate short-term pain and disability improvement in pain-dominant frozen shoulder, but trials have not demonstrated a durable long-term advantage, and it adds systemic glucocorticoid exposure.
- Hydrodilatation: may improve external rotation in some patients, but current evidence does not establish broad superiority over corticosteroid injection.
- Shockwave: an adjunct with randomized and pooled support, used alongside rehabilitation.
What are the limits of the evidence?
- Small trials: the strongest sham-controlled trial had 30 participants.
- Heterogeneity: range-of-motion and longer-term pain results varied widely between studies.
- Protocol variation: device type, energy and number of sessions differ.
- Population mix: several studies enrolled only diabetic patients.
- Follow-up: most outcomes are within three to six months.
These limits do not erase the positive findings, but they are why shockwave is selected for the individual presentation rather than used automatically.
Does shockwave break up the capsule?
No. Frozen shoulder involves genuine capsular fibrosis and contracture, but the trials measure pain, function and range of motion. They do not show that shockwave mechanically breaks up the capsule or regenerates it. Symptom and motion improvement is the supported claim.
Who may be a reasonable candidate?
Shockwave is most often considered when the examination confirms a capsular pattern of restricted passive motion, the diagnosis is not better explained by arthritis, a rotator cuff tear or calcific tendinopathy, and pain or stiffness is limiting progress with rehabilitation.
Who needs another pathway first?
- Significant trauma, a suspected fracture or dislocation
- Sudden marked weakness after an injury
- Progressive neurologic weakness or numbness
- Fever or feeling systemically unwell
- Severe unexplained pain
How Novo approaches frozen shoulder
We first confirm whether the shoulder is actually frozen. Radial shockwave and focused shockwave are options chosen by what the exam shows, alongside mobility work rather than in place of it. See how we approach frozen shoulder, or read about shockwave therapy in Denver and the four tools we use.
References
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- Zhang R, Wang Z, Liu R, et al. Extracorporeal shockwave therapy as an adjunctive therapy for frozen shoulder: a systematic review and meta-analysis. Orthopaedic Journal of Sports Medicine. 2022;10(2):23259671211062222. PMID 35141337. (link)
- El Naggar TEM, Maaty AIE, Mohamed AE. Effectiveness of radial extracorporeal shock-wave therapy versus ultrasound-guided low-dose intra-articular steroid injection in improving shoulder pain, function, and range of motion in diabetic patients with shoulder adhesive capsulitis. Journal of Shoulder and Elbow Surgery. 2020;29(7):1300-1309. PMID 32553435. (link)
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