Extracorporeal Shockwave Therapy for Tendinopathies Around the Hip and Pelvis: A Systematic Review

Abstract

Background: Tendinopathies affecting the hip and pelvis include proximal hamstring tendinopathy (PHT), gluteal tendinopathy (greater trochanteric pain syndrome [GTPS]), and calcific tendinopathy (CT). Extracorporeal shockwave therapy (ESWT) is a noninvasive treatment described for the management of lower-extremity tendinopathies. Purpose: We sought to synthesize the evidence on ESWT used in the treatment of hip/pelvis tendinopathies, including protocols, outcomes, and safety. Methods: A comprehensive search of PubMed/Medline, EMBASE, and Cochrane Library databases was performed on November 1, 2024, for studies reporting ESWT data for hip/pelvis tendinopathies. Study design, population, and ESWT-related data (protocols, outcomes, and safety) were extracted. Results: Eighteen studies were included; 9 reported on GTPS, 7 on CT, and 5 on PHT. Most ESWT protocols (72% [n = 13]) implemented 3 to 4 weekly sessions and delivered 2000 to 3000 pulses/session (83% [n = 15]). Eleven studies used radial ESWT and 7 used focused ESWT. ESWT significantly improved pain and functional outcomes for GTPS, CT, and PHT in 17 level-I to level-V studies; only 1 level-V study showed no improvement. Six studies showed superior outcomes post-ESWT vs conservative treatment (PHT/GTPS), sham ESWT (GTPS), ultrasound therapy (GTPS/CT), or corticosteroid injection (GTPS). One study showed comparable outcomes between ESWT and eccentric exercise (GTPS). Two studies reported no outcome differences between radial ESWT and “minimal-dose” ESWT (GTPS) or combined ESWT (PHT). All studies assessing pain showed improvement from 0.5 to 27 months post-ESWT. Six of 18 studies reported adverse events, including increased pain and skin irritation (overall rate: 12% [n = 65/557]). Conclusions: The results of this systematic review suggest that ESWT may be safe and effective for hip/pelvis tendinopathies. Future research using validated outcome measures and ESWT parameters will aid in treatment optimization.

Introduction

Tendinopathy is a common degenerative musculoskeletal disorder that can affect sports participation, employment, mental health, and quality of life. It is characterized by increased tendon thickness, pain, and reduced function [7]. Multiple tendinopathies around the hip and pelvis are evaluated in clinical practice. Proximal hamstring tendinopathy (PHT) presents as localized pain in the ischial tuberosity region and is most frequently seen in active people, including competitive and recreational distance runners [27]. Greater trochanteric pain syndrome (GTPS) is a regional pain diagnosis primarily due to gluteal tendinopathies and is most prevalent in women [19,32]. Calcific tendinopathy (CT) of gluteal and hamstring tendons has been reported, most commonly in the ages of 30 to 60 years, although its prevalence remains unclear [17,31]. In clinical practice, CT of gluteal and hamstring tendons are less common, especially compared to rotator cuff CT.

Most treatments for tendinopathies around the hip and pelvis are nonsurgical and include activity modification, analgesics (eg, acetaminophen) and non-steroidal anti-inflammatory drugs (NSAIDs), rest, physical therapy (PT), exercise, extracorporeal shockwave therapy (ESWT), platelet-rich plasma (PRP) or corticosteroid injections, and multimodal approaches [19,21]. Recent systematic reviews have shown moderate-to-high-quality evidence in support of exercise, PRP, and ESWT for short- and mid-term pain reduction and functional improvement for GTPS, PHT, and CT [6,10,36,40]. Multimodal and individualized approaches were recommended to optimize outcomes.

ESWT is a noninvasive treatment for various musculoskeletal disorders, including plantar fasciitis and tendinopathies [34]. Initial medical use of shockwaves was in lithotripsy procedures, where incidental effects were observed in iliac crest bone hypertrophy [1,11]. Although the mechanism is not entirely understood, ESWT may have therapeutic effects through cellular mechanotransduction that alters pain signaling and promotes tissue regeneration through increased collagen synthesis, osteoprogenitor differentiation, and leukocyte proliferation [4,12,44-46]. Two primary forms of ESWT are used in clinical practice. Radial ESWT (rESWT) generates pressure waves with maximal energy at the applicator, whereas focused ESWT (fESWT) generates maximal energy at greater depths in tissue [43]. Focused ESWT is generated by piezoelectric, electrohydraulic, or electromagnetic devices, with each pulse lasting ~10µs and exhibiting a quick pressure rise time, high maximum pressure (10-100MPa), and a brief negative pressure phase [25]. In contrast, rESWT uses accelerated projectiles and compressed air to generate pulses that last ~10 ms and exhibit a relatively slow pressure increase, a maximum pressure of 0.1 MPa to 1 MPa, and no cavitation phase [5].

Previous review articles have found low-to-moderate levels of evidence in favor of rESWT and a relative lack of evidence in support of fESWT as short- and mid-term treatment modalities for PHT and GTPS [18,23,36,37]. However, due to a lack of standardization, ESWT protocols vary widely in the literature. As the body of ESWT research grows in breadth and specificity, there is a need for up-to-date review articles. We, therefore, sought to perform a systematic review of the literature on ESWT as a treatment for tendinopathies of the hip and pelvis.

Methods

A comprehensive search of the PubMed/Medline, EMBASE, and Cochrane Library databases was performed on November 1, 2024, in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Search terms included “shockwave,” “shock wave,” “ESWT,” “extracorporeal shockwave therapy,” “extracorporeal shockwave therapies,” “extracorporeal shock wave therapy,” “extracorporeal shock wave therapies,” “extracorporeal pulse-activated therapy,” “extracorporeal pulse-activated therapies,” “tendinopathy,” “tendinosis,” “tendinitis,” “hip joint,” “hip,” “pelvis,” “hamstring,” “hamstring tendons,” “hamstring muscles,” and “rectus femoris” (Supplemental Table 1). Studies reporting ESWT data for tendinopathies of the hip and pelvis that were published from database inception to October 2024 were included. Studies were excluded for the following reasons: non-English language; lack of ESWT-related data; and lack of hip or pelvic tendinopathy-related data. Using the Covidence software program (Veritas Health Innovation Ltd; Melbourne, Australia), 2 authors (J.C., O.R.) independently screened the studies, starting with the titles and abstracts, followed by full-text reviews. Disagreements were resolved through consensus. Reference lists of eligible studies and review articles were reviewed for relevant studies.

Study design, population, and ESWT-related data were independently extracted from full-text articles. Study population included gender, age, diagnosis, symptom duration, laterality, and sports participation. ESWT-related data included location, session numbers and intervals, number of pulses, intensity, frequency, post-procedure guidelines, and/or outcomes. Outcome measures included imaging, numerical rating scale (NRS) pain, visual analog scale (VAS) pain, Harris hip score (HHS), Roles and Maudsley (RM) treatment satisfaction score, Lower-Extremity Functional scale (LEFS), EuroQol-5 Dimensions questionnaire, Likert scale for degree of recovery, VISA-Hamstring, PT progression, and return to sport. Short-term and long-term outcomes were collected when available. Data were also summarized by ESWT type and diagnosis.

Two authors (J.C., O.R.) independently assessed the quality of the included studies. The assessment of cohort and case-control studies was performed using the Newcastle-Ottawa Scale (NOS), which had selection, comparability, and outcome parameters [47]. “Selection” included assessing the representativeness of the exposed cohort (patients receiving ESWT) and determining whether the outcome of interest was present at the start of the study. “Comparability” included assessing the availability of cohorts treated with or without ESWT. “Outcome” included assessing the availability of an outcome, the follow-up time interval, and the adequacy of follow-ups. Randomized controlled trials (RCT) were assessed using the Cochrane Risk of Bias Tool v2 (RoB 2) [15], which addressed the presence of random sequence generation, allocation concealment, selective reporting, other sources of bias, blinding, and the quality of outcome data. The Joanna Briggs Institute critical appraisal tool was used to assess internal validity, methodology, and risk of bias in case reports [26].

Results

A PRISMA flowchart for the study selection process is shown in Fig 1. The systematic review included a total of 18 studies that focused on GTPS (n = 9), CT of the hip or pelvic region (n = 7), and PHT (n = 5). The studies included 8 level-I RCTs [2,3,14,29,33,39,48,49]; 3 level-III studies (2 retrospective cohort studies [24,42] and 1 level-III case-control study [9]); 1 level-IV quality improvement study [50]; and 6 level-V case reports [13,16,20,30,35,41]. Eight studies involved comparator groups, including rest and NSAIDs, traditional PT, physiotherapy, home exercise programs (HEP), eccentric exercise, ultrasound therapy, corticosteroid injections, and sham ESWT [2,3,9,14,29,33,39,49]. Two studies involved comparisons between different types of ESWT [48,50]. Study characteristics are shown in Table 1.

Fig. 1.

PRISMA flow diagram.

Table 1.

Study characteristics.

First author	Year published	Study design, level of evidence	Population	Relevant diagnoses	ESWT type	Comparator groups
Cacchio [2]	2011	RCT, level-I	Pro athletes	PHT	Radial	Traditional nonoperative therapy (wk1: rest, NSAIDs; wk1-2: physiotherapy; last 3wks: exercise [hamstring stretching, strengthening])
Carlisi [3]	2019	RCT, level-I	General	Chronic GTPS	Focused	Ultrasound therapy
Furia [9]	2009	Case-control study, level-III	General	Chronic GTPS; presence of CT not reported	Radial	Traditional nonoperative therapy (not specified)
Hayano [13]	2021	Case report, level-V	Para-swimmer	PHT	Radial	NA
Heaver [14]	2023	RCT, level-I	General	Chronic GTPS	Focused	corticosteroid injection
Jo [16]	2016	Case report, level-V	General	CT of gluteus medius	Radial	NA
Lee [20]	2019	Case report, level-V	General	CT of rectus femoris	Focused	NA
Mitchkash [24]	2020	Retrospective cohort, level-III	Runners	PHT	Radial	NA
Notarnicola [29]	2023	RCT with cross-over, level-I	General	Chronic GTPS; CT	Focused	Eccentric exercise (stretching, strengthening; 20 sessions: 4wks, 5days/wk, 30min/day)
Oh [30]	2010	Case report, level-V	General	CT near pectineus and gluteus maximus; calcific tendinitis of the rectus femoris	Focused	NA
Ramon [33]	2020	RCT, level-I	General	Chronic GTPS with no calcification	Focused	Sham ESWT
Reilly [35]	2020	Case report, level-V	Runner	PHT	Radial	NA
Rompe [39]	2009	RCT, level-I	General	Chronic GTPS; presence of CT not reported	Radial	Home exercise program (piriformis stretch, iliotibial band stretch standing, straight leg raise, wall squat with ball, gluteal strengthening; daily for 12 wks); corticosteroid injection
Savevska [41]	2018	Case report, level-V	General	CT of gluteus medius	Radial	NA
Seo [42]	2018	Retrospective cohort study, level-III	General	Chronic GTPS; CT	Focused	NA
Wheeler [48]	2022	RCT, level-I	General	Chronic GTPS	Radial	“minimal-dose” ESWT
Yagci [49]	2023	RCT, level-I	General	Chronic GTPS	Radial	corticosteroid injection
Yun [50]	2021	Quality improvement, retrospective review, level-IV	Runners	PHT	2 types: radial; combined (radial + focused)	NA

CT calcific tendinopathy, ESWT extracorporeal shockwave therapy, GTPS greater trochanteric pain syndrome, NA not applicable, NSAID nonsteroidal anti-inflammatory drug, PHT proximal hamstring tendinopathy, RCT randomized controlled trial, wk, week.

Altogether, the studies included 927 individuals (682 females, 245 males), with an average age of 50.7 years. Of these, 586 (431 females, 155 males) were treated with ESWT (average age: 51.5 years). Five studies focused on active populations (average age: 39.4 years), including runners presenting to a running medicine clinic [24,50], professional athletes [2], a para-swimmer [13], and an ultra-marathon runner [35]. The remaining 13 studies included patients of all activity levels (average age: 54.8 years).

Radiographs, ultrasonography, and MRIs were widely employed for diagnostic purposes and occasionally for outcome assessment. Nearly all studies assessed patients experiencing chronic tendinopathy, defined by a period of either 3 or 6 months. Mitchkash et al did not report symptom duration [24], and Oh et al reported treatment after 1 month of symptoms for a calcific nodule shown on radiographs [30].

Focused ESWT

Seven studies (including 2 case reports) reported outcomes using fESWT to treat GTPS and CT [3,14,20,29,30,33,42]. Notarnicola et al found imaging evidence of CT in 6 out of 22 participants with GTPS, while Seo et al found the same in 5 out of 18 participants. Outcomes were not assessed separately for patients with or without CT [29,42]. Carlisi et al also reported imaging evidence of CT in 40 out of 50 participants with GTPS in their entire cohort, but did not provide a breakdown of CT by treatment group [3]. Five studies involved 3 sessions at weekly intervals [3,14,29,30,33]; for the other 2, Seo et al used up to 11 weekly sessions based on treatment success and patient’s willingness to continue treatment [42], and Lee et al employed 6 sessions at an interval of 3 to 4 days to treat CT of the rectus femoris [20]. ESWT parameters varied among studies. The number of pulses per session ranged from 600 to 2500, although 2000 was the most common. Pulse frequency ranged from 1 Hz to 5 Hz, most commonly 4 Hz. Energy flux densities (EFDs) varied both across and within protocols. Depending on pain tolerance, Notarnicola et al reported EFDs from 0.03 mJ/mm² to 0.17 mJ/mm² [29], and Heaver et al reported EFDs from 0.15 mJ/mm² to 0.35 mJ/mm² [14]. Seo et al and Lee et al used an EFD of 0.10 mJ/mm² [20,42], Carlisi et al and Oh et al used 0.15 mJ/mm² [3,30], and Ramon et al used 0.20 mJ/mm² [33].

Outcomes following fESWT were assessed at various timepoints up to 2 years (Table 2). For the 7 studies utilizing fESWT to treat GTPS and/or CT, favorable outcomes were reported using various outcome measures [3,14,20,29,30,33,42]. In studies assessing patients with GTPS, with or without imaging evidence of CT, Carlisi et al, Heaver et al, Notarnicola et al, Ramon et al, and Seo et al found significant decreases in pain (average 3.9-point reduction, n = 165) up to 12 months following fESWT when compared to baseline. LEFS scores, which evaluate the functional ability to complete everyday tasks, showed variable results: Carlisi et al reported no improvement from baseline or in comparison to ultrasound therapy, up to 6 months [3]; Notarnicola et al demonstrated significant improvement up to 6 months post-fESWT when compared to baseline, but not eccentric exercise [29]; and Ramon et al reported significant improvement up to 6 months post-fESWT versus baseline and sham ESWT (control) [33]. Ramon et al and Seo et al utilized RM scores to assess treatment satisfaction; most patients reported excellent or good treatment satisfaction, from 2 months to 2 years post-fESWT [33,42].

Table 2.

Focused ESWT study characteristics and outcomes.

Study	Diagnoses	Symptom duration	ESWT parameters	Outcome measures a	Outcome findings	Return to sport	Side Effects
Carlisi 2019 [3]	GTPS (n = 26) and CT (~80% of cohort)	≥6 m	3 weekly sessions; 1800 pulses; 0.15 mJ/mm2; 4 Hz	NRS, LEFS	CS decrease in NRS pain at 2 and 6 m; SS greater NRS pain improvement post-ESWT vs. US therapy; no SS improvement in LEFS score	Not reported	Increased pain: 8% (2/26)
Heaver 2023 [14]	GTPS without CT (n = 53)	≥6 m	3 weekly sessions; 2500 pulses; 0.15-0.35 mJ/mm2; unknown frequency	VAS, HHS, Trendelenburg test, SF-36, Likert scale of symptom improvement	All outcome measures showed SS improvement at 3 and 12 m; SS greater VAS and HHS improvement post-ESWT vs. CSI at 12 m; greater likelihood of negative Trendelenburg test post-ESWT vs. CSI	Not reported	None
Lee 2019 [20]	CT of rectus femoris (n = 1)	6 m	6 sessions every 3-4 days; 2500 pulses; 0.10 mJ/mm2; 4 Hz	Pain, XR, ultrasound	Pain resolution by 6 weeks; US showed disintegration of calcium deposit into smaller pieces vs. pre-ESWT XR	Not reported	None
Notarnicola 2023 [29]	GTPS (n = 22) and CT (n = 6/22)	>3 m	3 weekly sessions; 2000 pulses; 0.03-0.17 mJ/mm2; 4 Hz	NRS, LEFS, RM	All outcome measures showed SS improvement at 2, 4, 6 m; no differences between eccentric exercise, fESWT, and cross-over groups	Not reported	Not reported
Oh 2010 [30]	CT of pectineus and gluteus maximus (n = 2)	≥1 m	3 weekly sessions; 2000 pulses; 0.15 mJ/mm2; 4 Hz; unspecified complementary NSAIDs	VAS, XR	Case 1: 7-point decrease in VAS pain over ESWT course; calcium deposit disintegration at 4 w XR; Case 2: resolution of pain, calcium deposit resorption at 15 m	Not reported	None
Ramon 2020 [33]	GTPS (n = 53); CT excluded	>3 m	3 weekly sessions; 2000 pulses; 0.20 mJ/mm2; 5 Hz; daily HEP for 24 weeks, starting at ESWT onset	VAS, HHS, LEFS, EQ-5D, RM	Outcome scores showed SS improvement at 1, 3, 6 m; RM success rate: 64.2%; SS greater improvement in outcomes (except LEFS at 1 m) vs. sham ESWT at 1, 3, 6 m	Not reported	None
Seo 2018 [42]	GTPS (n = 18) and CT (n = 5/18)	≥6 m	≤11 weekly sessions (average: 5.5); 600 pulses; 0.10 mJ/mm2; 1 Hz	NRS, RM	SS improvement in NRS scores at immediate and long-term follow-ups; RM success rates: 83.3% (immediate), 55.6% (long-term)	Increased activity capacity at immediate and long-term follow-ups	None

CS clinically significant, CT calcific tendinopathy, EFD energy flux density, EQ-5D EuroQol-5 Dimensions, ESWT extracorporeal shockwave therapy, HEP home exercise program, HHS: Harris hip score, LEFS lower-extremity functional scale, m, months, NRS numerical rating scale, NSAID non-steroidal anti-inflammatory drug, RM Roles and Maudsley treatment satisfaction, SS statistically significant, US ultrasound, VAS visual analog scale, XR x-ray.

^aNRS and VAS scores measure pain intensity (0-10 scale; 0 = no pain, 10 = severe pain); EQ-5D assesses quality of life with subsections of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression (lower scores = worse quality of life; higher scores = better quality of life); HHS assesses hip-related disability (0-100 scale; <70 = poor, 70-80 = fair, 80-90 = good, 90-100 = excellent); LEFS assesses ability to perform everyday tasks (higher scores indicate greater ability); RM assesses treatment satisfaction (1 = excellent result with no symptoms following treatment; 2 = significant improvement from pretreatment; 3 = somewhat improved; 4 = poor, symptoms identical or worse than pretreatment).

The 2 case reports that reported outcomes using fESWT to treat GTPS and CT involved 3 patients with GTPS and CT: 2 localized at the rectus femoris [20] and 1 at the femoral insertion of the pectineus and gluteal maximus [30]. All patients reported significant pain relief over the course of treatment. Lee et al found no difference in the calcium deposit on plain radiographs post-treatment, but ultrasonography showed disintegration of the deposit into many smaller pieces [20]. Oh et al reported the disintegration and resorption of calcium deposits on plain radiographs following treatment in 2 cases [30].

Overall, no major complications following fESWT were reported. Side effects were uncommon (1%; n = 2/175) and included increased or lasting pain necessitating pain medication, as reported by Carlisi et al [3]. The duration and degree of this increased or lasting pain were not specified.

Radial ESWT

Eleven studies (including 4 case reports) utilized rESWT to treat PHT [2,13,24,35], GTPS [9,39,48,49], and CT [9,16,39,41], with large variability across protocols. Most rESWT studies involved 3 to 4 sessions at weekly intervals, although Furia et al [9] used only 1 session for GTPS, and Hayano et al administered 15 sessions over 24 weeks [13]. The number of pulses administered per session ranged from 2000 to 3000, with frequencies ranging from 8 Hz to 20 Hz. Bar pressure ranged from 2.0 to 4.5 bar.

Two studies utilized variations of ESWT in their comparative groups. Wheeler et al administered “minimal-dose” rESWT to their control group; treatment involved 3 weekly sessions of 500 pulses and 1.4 bar of pressure, at a frequency of 20 Hz [48]. Yun et al used combined ESWT in their comparative cohort; these patients received ≥4 weekly sessions of both fESWT (1000 pulses, 0.12 mJ/mm² to 0.5 mJ/mm², 15 Hz) and rESWT (3000 pulses, 2.5 bar to 5.0 bar, 15 Hz) [50].

Outcomes for rESWT studies were assessed at various timepoints up to 15 months (Table 3). Positive outcomes were reported by all rESWT studies, except for 1 case report that discontinued treatment due to pain aggravation [16]. All studies investigating rESWT to treat PHT were performed in active populations [2,13,24,35,50]. Clinically significant improvements in pain and/or function following ESWT treatment were observed in studies by Cacchio et al, Mitchkash et al, and Yun et al [2,24,50]. In a cohort of professional athletes, Cacchio et al reported post-ESWT outcomes that were superior to those following traditional conservative therapy comprising rest, NSAIDs, physiotherapy, and exercise, with 80% of athletes returning to sport within 3 months post-ESWT [2]. Yun et al compared outcomes in runners who were treated with rESWT versus combined ESWT and showed improvements in both groups, without any between-group differences [50]. Furthermore, both case reports utilizing rESWT to treat PHT showed significant improvements in pain and the ability to increase sport participation and/or fully return to sport [13,35].

Table 3.

Radial ESWT study characteristics and outcomes.

Author	Diagnoses	Symptom duration	ESWT parameters	Outcome measures a	Outcome findings	Return to sport	Side effects
Cacchio 2011 [2]	PHT (n = 20)	19.6 ± 5.8 m	4 weekly sessions; 2500 pulses; 4 bar; 10 Hz; interval icing post-ESWT recommended	VAS, NPRS	CS improvement VAS and NPRS at 3, 6, 12 m; SS more improvement vs. rest, NSAID, physiotherapy	80% by 3 m; avoided competition during ESWT	None
Furia 2009 [9]	GTPS (n = 33)	≥6 m	1 session; 2000 pulses; 4 bar; 1 Hz; discouraged concurrent interventions for 3 m	VAS, HHS, RM	CS improvement, all measures, at 1, 3, 12 m; more improvement with ESWT vs. controls	Not reported	Increased pain: 6% (2/33); skin reddening: 6% (2/33)
Hayano 2021 [13]	PHT (n = 1)	~1 year	15 sessions; 3000 pulses; 4-4.5 bar; 15 Hz; concurrent PT	Pain, function, PT progress	Reduced pain; improved sitting tolerance	Increased swimming performance; PT progression	None
Jo 2016 [16]	CT of gluteus medius (n = 1)	>4 m	3 sessions every 3-4 days; 2000 pulses; 3.75 bar; unknown frequency	Pain	Discontinued ESWT; symptom resolution after US-guided barbotage	Increased comfort with walking	Increased pain following ESWT
Mitchkash 2020 [24]	PHT (n = 32)	21.5 ± 3.0 m	≥4 weekly sessions; unknown pulses; 2-5 bar; 12-15 Hz; encouraged concurrent PT or HEP; avoid NSAIDs and icing post-ESWT	VISA-H	69% (22/32) were CS; shorter symptom duration for those meeting CS criteria	Patients ran or cross-trained as tolerated; no specific outcomes reported	No major complications
Reilly 2020 [35]	PHT (n = 1)	3 m	5 weekly sessions; 3000 pulses; 4.5 bar; 15 Hz; avoid NSAIDs and minimize icing post-ESWT	Pain, sport capacity	Able to run 12-15 km at a time during ESWT course; pain progressively improved	Trained throughout ESWT; full return with no pain by 10 m post-ESWT	None
Rompe 2009 [39]	GTPS (n = 78)	≥6 m	Weekly sessions; 2000 pulses; 3 bar; 8 Hz; discouraged concurrent interventions for 4 m	Likert scale of recovery	Success rates: 68% (4 m), 74% (15 m); SS difference in favor of ESWT over HEP at 4 m (no difference at 1, 15 m)	64% (50/78) by 4 m	Skin irritation: 33% (26/78); increased pain[1 day]: 10% (8/78); radiating pain: 4% (3/78); increased pain >1 day: 2% (2/78); swelling: 2% (2/78); other: 1% (1/78)
Savevska 2018 [41]	CT of gluteus medius (n = 1)	~4 m	4 weekly sessions; 2000 pulses; 2.5 bar; 10 Hz	NRS, range of motion, XR	Reduced NRS pain, increased hip range of motion post-ESWT; follow-up XR showed disintegration of calcific nodule	Not reported	None
Wheeler 2022 [48]	GTPS (n = 120; 57 received treatment ESWT; 63 received “minimal-dose” ESWT)	≥6 m	Treatment ESWT: 3 weekly sessions; 2000 pulses; 2.3-3.3 bar; 20 Hz; “Minimal-dose” ESWT: 3 weekly sessions; 500 pulses; 1.4 bar; 20 Hz; daily HEP for 6 m	NRS, OHS, NAHS, VISA-G, sleep quality	SS improvement in pain, function, and sleep at 6 wks, 3 m, and 6 m in both groups; no between-group differences in outcomes	Not reported	Minor bruising: 3% (4/120)
Yagci 2023 [49]	GTPS (n = 32)	≥6 w	3 weekly sessions; 2000 pulses; 2 bar; 12 Hz; paracetamol post-ESWT allowed but discouraged	NRS, VAS, WOMAC, SF-36	SS improvement in outcome measures at 3 wks and 3 m; no differences between ESWT and CSI groups	Not reported	Increased pain: 12/32 (38%)
Yun 2021 [50]	PHT (n = 63; 40 received radial ESWT; 23 received combined ESWT)	16.9 ± 23.8 m	Radial ESWT: ≥4 weekly sessions, 3000 pulses; 2.5-5.0 bar; 15 Hz; Combined ESWT: ≥4 weekly sessions of focused ESWT (1000 pulses; 0.12-0.5 mJ/mm2; 15 Hz) and radial ESWT (as above); instructed to avoid NSAIDs and minimize icing post-ESWT	VISA-H	SS increase in VISA-H at 6-8 wks in both groups; 63% in radial ESWT and 57% in combined ESWT groups met CS criteria	Not reported	None

CS clinically significant, ESWT extracorporeal shockwave therapy, HEP home exercise program, HHS Harris hip score, m months, NPRS Nirschl Phase Rating Scale, NRS numerical rating scale, NSAID non-steroidal anti-inflammatory drug, PHT proximal hamstring tendinopathy, PT physical therapy, RM Role and Maudsley Treatment Satisfaction, SS statistically significant, US ultrasound, VAS visual analog scale, VISA-H Victorian Institute of Sport Assessment-Hamstring, XR x-ray.

^aNRS and VAS scores measure pain intensity (0-10 scale; 0 = no pain, 10 = severe pain); EQ-5D assesses quality of life with subsections of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression (lower scores = worse quality of life; higher scores = better quality of life); HHS assesses hip-related disability (0-100 scale; <70 = poor, 70-80 = fair, 80-90 = good, 90-100 = excellent); Likert scale of recovery assesses degree of recovery following treatment (higher scores = greater degree of recovery); NPRS assesses pain-related disability (1-7 scale; 1 = mild stiffness or soreness after activity with symptom resolution within 24 hours; 7 = constant rest pain that disturbs sleep); RM assesses treatment satisfaction (1 = excellent result with no symptoms following treatment; 2 = significant improvement from pretreatment; 3 = somewhat improved; 4 = poor, symptoms identical or worse than pretreatment); VISA-H assesses pain and function in patients with PHT (higher scores = less pain and greater function).

In addition, 3 studies assessed rESWT as a treatment for GTPS. Furia et al retrospectively compared outcomes from patients who elected to pursue PT only or one session of rESWT without PT, using a case-control study design [9]. Rompe et al conducted an RCT comparing a standard HEP, corticosteroid injections, and 3 sessions of rESWT; rESWT and exercise intervention that were not administered simultaneously [39]. Wheeler et al conducted an RCT comparing 3 sessions of rESWT to 3 sessions of “minimal-dose” rESWT, which employed lower numbers of pulses and bars of pressure[48]. All 3 studies reported improvement in symptoms at all timepoints for the rESWT groups. Furia et al found significantly more improvement in VAS and HHS (hip disability) scores compared to the PT group at all timepoints [9]. Rompe et al found comparable results between their rESWT and HEP groups at 1- and 15-month follow-ups [39]. Wheeler et al reported similar improvements in pain, function, and sleep at all timepoints up to 6 months in both intervention rESWT and “minimal-dose” ESWT groups. Furthermore, all 3 studies reported some minor adverse reactions, including skin irritation, bruising, and increased pain immediately following treatment.

Two case reports assessed rESWT as a treatment for patients with CT of the gluteus medius [16,41]. Savevska et al successfully treated CT with 4 sessions of rESWT on a woman with osteoporosis [41]. The patient reported pain resolution and increased range of motion, and a repeat radiograph showed the calcific nodule was completely resolved. Jo et al attempted to treat a calcific nodule at the gluteus medius insertion with 3 sessions of rESWT; however, treatment was discontinued due to reported pain aggravation [16]. The patient was subsequently treated with ultrasound-guided barbotage with success.

Overall, no major complications were reported in studies utilizing rESWT. Minor complications or side effects occurred at a rate of 16% (n = 63/382) and most commonly included skin irritation and increased pain. Most cases of increased pain occurred during the 24 hours immediately post-ESWT and resolved with pain medication use.

Quality Assessment

Cohort studies were evaluated using the NOS, with a maximum score of 9 [47]; 3 had lower scores, suggesting higher risk, because they were retrospective in nature and lacked a control group (Supplemental Table 2). The 8 RCTs were assessed using the RoB2 [15]; 3 had a low risk of biased judgment [2,3,14], 2 had some concerns for risk [33,48], and 3 had a high risk [29,39,49] (Supplemental Table 3). The JBI appraisal tool for case reports was used to assess the 6 case reports [26]; scores ranged from 10 to 13 out of 16 possible points (Supplemental Table 4).

Discussion

This systematic review assessed the current literature investigating fESWT and rESWT for the treatment of tendinopathies related to the hip and pelvis. Eighteen studies involving GTPS, PHT, and/or CT were included and summarized. Despite protocol variation with regard to intensities, pulses, session numbers, and session intervals, the findings of this review suggest that ESWT is safe and effective.

There are several limitations to this systematic review. Of the 18 included articles, 6 were case reports, which limits the generalizability of our findings. However, 5 of the case reports involved CT of the hip/pelvis area, a limited area in the ESWT literature, which provides greater insight into post-ESWT outcomes and safety profiles in both general and active populations. In addition, the study quality of the remaining 12 cohort studies and RCTs varied widely, with 6 deemed to have a higher risk. Furthermore, ESWT protocols and outcomes assessments were not uniform across studies, thus limiting the ability to quantitatively synthesize the data. Importantly, only 1 study utilized a combination of fESWT and rESWT, and no studies performed head-to-head comparisons of fESWT and rESWT. Lastly, most studies that reported on CT in addition to other diagnoses did not differentiate between diagnoses when assessing outcomes. Having this differentiation would be helpful in future research to better understand who benefits from ESWT, particularly for CT of the hip/pelvis, as it is less commonly diagnosed overall.

The efficacy of ESWT in the treatment of several musculoskeletal conditions of the foot and ankle, including Achilles tendinopathy and plantar fasciitis, has been well documented in the literature [28]. Several systematic reviews have investigated outcomes following ESWT in the treatment of lower limb tendinopathies unrelated to the foot and ankle, such as patellar tendinopathy, gluteal tendinopathy (or GTPS), PHT, and CT [8,18,22,23,34,36]. Most review articles have supported the efficacy of ESWT treatment in lower limb tendinopathies, with varying degrees of superiority when compared to other nonoperative treatments. However, many of these review articles are structured around specific diagnoses and do not provide categorizations by ESWT type.

The current systematic review adds to the literature and provides a comprehensive, updated summary of both fESWT and rESWT in the treatment of GTPS, PHT, and CT of the hip or pelvis region. Focused ESWT was used to treat GTPS and/or CT and showed pain and functional improvements, as well as high patient satisfaction, following treatment. Radial ESWT was used to treat PHT, GTPS, and/or CT, and similarly demonstrated pain and functional improvements, apart from one case report involving CT. In most cases, rESWT was used to treat PHT, and all patients with PHT were athletes. The study that utilized a combination of rESWT and fESWT as a comparative group showed pain and functional improvements similar to those of rESWT alone [50].

Protocols for ESWT continued to vary among the studies included in the systematic review. For fESWT, the EFD ranged widely from 0.03 mJ/mm² [29] to 0.35 mJ/mm² [14] among the 7 studies utilizing fESWT alone, with most studies within the 0.10 mJ/mm² to 0.20 mJ/mm² range. Yun et al reported an even higher EFD of 0.5 mJ/mm² as the upper range in patients receiving a combination of fESWT and rESWT [50]. An in vivo study assessing EFD dose-related effects of ESWT on histological changes and inflammation in the Achilles tendons of rabbits showed that EFDs over 0.28 mJ/mm² were associated with significant inflammation, necrosis, and fibrosis within the tendon. The authors concluded that ESWT should not utilize EFDs >0.28 mJ/mm² in the clinical treatment of tendon disorders [38]. However, it is unclear whether the same findings may be observed in tendons surrounding the hip and pelvis areas, and how this may apply clinically to tendinopathies of the hip and pelvis. For rESWT, EFDs ranged from 1.4 to 4.5 bar among 11 studies, with 1.4 bar used as a “minimal-dose” comparison in one study [48]. Despite the large variations in ESWT protocols, particularly with EFDs, positive outcomes were observed overall.

Previous review articles have provided limited information on complications and side effects. Our review found no serious adverse events reported, suggesting the overall safety of ESWT in the treatment of hip- and pelvis-related tendinopathies. Side effect rates were low and included skin irritation and increased pain. In most cases, increased pain resolved quickly with the use of pain medications.

Although ESWT protocols for hip- and pelvis-related tendinopathies continue to vary, findings from this systematic review suggest that ESWT can be used to safely and effectively treat GTPS, PHT, and CT of the hip/pelvis region. For GTPS and CT, both fESWT and rESWT led to improvements in pain and functional outcomes, with minimal side effects. For PHT, which affected only the athlete population in this review, rESWT effectively improved pain and function and allowed most athletes to return to sport. Future studies are needed to better develop standardized protocols for fESWT and/or rESWT in patients with hip- and pelvis-related tendinopathies and to evaluate if they add benefit to PT/HEP compared to PT/HEP alone.