Prognostic factors of extracorporeal shock wave therapy for tendinopathies

Predictive Prognostic Factors in Non-Calcific Supraspinatus Tendinopathy Treated with Focused Extracorporeal Shock Wave Therapy: An Artificial Neural Network Approach

The supraspinatus tendon is one of the most involved tendons in the development of shoulder pain. Extracorporeal shockwave therapy (ESWT) has been recognized as a valid and safe treatment. Sometimes the symptoms cannot be relieved, or a relapse develops, affecting the patient's quality of life. Therefore, a prediction protocol could be a powerful tool aiding our clinical decisions. An artificial neural network was run, in particular a multilayer perceptron model incorporating input information such as the VAS and Constant-Murley score, administered at T0 and at T1 after six months. It showed a model sensitivity of 80.7%, and the area under the ROC curve was 0.701, which demonstrates good discrimination. The aim of our study was to identify predictive factors for minimal clinically successful therapy (MCST), defined as a reduction of ≥40% in VAS score at T1 following ESWT for chronic non-calcific supraspinatus tendinopathy (SNCCT). From the male gender, we expect greater and more frequent clinical success. The more severe the patient's initial condition, the greater the possibility that clinical success will decrease. The Constant and Murley score, Roles and Maudsley score, and VAS are not just evaluation tools to verify an improvement; they are also prognostic factors to be taken into consideration in the assessment of achieving clinical success. Due to the lower clinical improvement observed in older patients and those with worse clinical and functional scales, it would be preferable to also provide these patients with the possibility of combined treatments. The ANN predictive model is reasonable and accurate in studying the influence of prognostic factors and achieving clinical success in patients with chronic non-calcific tendinopathy of the supraspinatus treated with ESWT.

Extracorporeal Shock Wave Therapy for the Treatment of Musculoskeletal Pain: A Narrative Review

Extracorporeal shock waves are high-intensity mechanical waves (500-1000 bar) of a microsecond duration with a morphology characterized by a rapid positive phase followed by a negative phase.

BACKGROUND

Extracorporeal shock waves have been used for pain treatment for various sub-acute and chronic musculoskeletal (MSK) problems since 2000. The aim of this article is to update information on the role of extracorporeal shock wave therapy (ESWT) in the treatment of various pathologies that cause MSK pain.

METHODS

Given that in the last two years, articles of interest (including systematic reviews and meta-analyses) have been published on less known indications, such as low back pain, nerve entrapments, osteoarthritis and bone vascular diseases, a literature search was conducted in PubMed, the Cochrane Database, EMBASE, CINAHL and PEDro, with the aim of developing a narrative review of the current literature on this topic. The purposes of the review were to review possible new mechanisms of action, update the level of evidence for known indications and assess possible new indications that have emerged in recent years.

RESULTS

Although extracorporeal shock waves have mechanical effects, their main mechanism of action is biological, through a phenomenon called mechanotransduction. There is solid evidence that supports their use to improve pain in many MSK pathologies, such as different tendinopathies (epicondylar, trochanteric, patellar, Achilles or calcific shoulder), plantar fasciitis, axial pain (myofascial, lumbar or coccygodynia), osteoarthritis and bone lesions (delayed union, osteonecrosis of the femoral head, Kienbock's disease, bone marrow edema syndrome of the hip, pubis osteitis or carpal tunnel syndrome). Of the clinical indications mentioned in this review, five have a level of evidence of 1+, eight have a level of evidence of 1-, one indication has a level of evidence of 2- and two indications have a level of evidence of 3.

CONCLUSIONS

The current literature shows that ESWT is a safe treatment, with hardly any adverse effects reported. Furthermore, it can be used alone or in conjunction with other physical therapies such as eccentric strengthening exercises or static stretching, which can enhance its therapeutic effect.

Therapeutic effects following extracorporeal shock wave therapy for insertional and non-insertional Achilles tendinopathy

Background

The treatment for Achilles tendinopathy varies widely, and there is no consensus regarding the optimal treatment for both non-insertional and insertional Achilles tendinopathy. The purpose of this study was to evaluate the clinical efficacy of extracorporeal shock wave therapy (ESWT) in the treatment of insertional and non-insertional Achilles tendinopathy (AT).

Methods

Sixty patients with AT were invited to participate in this study. Patients were allocated to one of two groups according to the site of the AT, including an insertional AT (IAT) group and a non-insertional AT (NIAT) group. ESWT was performed once a week for five weeks for both groups. The Victorian Institute of Sport Assessment-Achilles questionnaire (VISA-A) score and the visual analog scale (VAS) were used five times to evaluate the clinical outcomes, including before treatment, immediately after treatment, as well as one month, three months, and five years after treatment.

Results

At three months after treatment, the IAT group exhibited a significantly higher VISA-A score (82 ± 6 vs. 76 ± 11; p = 0.01) and a significantly lower VAS score (1 ± 1 vs. 2 ± 1; p < 0.001) when compared with the NIAT group. At the five-year assessment, the IAT group (1 ± 1) had a significantly lower VAS score than the NIAT group (2 ± 1) (p = 0.02), while no significant difference for the VISA-A score was observed between the groups (84 ± 8 vs. 84 ± 10; p = 0.98).

Conclusions

Extracorporeal shock wave treatment can improve the symptoms of both insertional and non-insertional AT. The IAT patients experienced better clinical outcomes compared with the NIAT patients.

Effectiveness of combined extracorporeal shock-wave therapy and hyaluronic acid injections for patients with shoulder pain due to rotator cuff tendinopathy: a person-centered approach with a focus on gender differences to treatment response

Background

Rotator cuff (RC) tendinopathy is a common shoulder pain condition. Extracorporeal shockwave therapy (ESWT) and hyaluronic acid peritendinous injection are viable treatment options for RC tendinopathy.

The aim of this study is to evaluate the response in two different therapeutic rehabilitative approaches, the combined treatment ESWT plus hyaluronic acid injections (E + Hy) compared to ESWT alone (ESWT-al), in a cohort of patients with RC tendinopathy according to gender differences.

Methods

This is a retrospective longitudinal cohort study of patients with painful RC tendinopathy. Patients that had received a clinical evaluation, a shoulder ultra sound examination, as well as the Shoulder Pain and Disability Index (SPADI) questionnaire, and the Numerical Rating Scale (NRS) for pain at baseline, 1-month (T1) and 2-month follow-ups (T2) were included.

Results

Medical records of 53 patients were analyzed. In the comparison between baseline to T1 and similarly from baseline to T2, a statistically significant reduction has been reported in the NRS (p < 0.001) and in the SPADI (p < 0.001) in the entire study group. At T1, patients in the E + Hy compared to ESWT-al group, showed a slight but statistically significant reductions in both NRS and SPADI score, while these changes were more evident at T2 (p < 0.001). Interestingly, a gender dimorphism in NRS and in SPADI was found, with female patients that apparently responded better to the combined E + Hy compared to ESWT-al approach.

Conclusion

This retrospective cohort study suggests that the combination of ESWT plus HyA injections seems to be more effective than ESWT alone in RC tendinopathy in both genders. Moreover, in ESWT alone treatment, male patients reported better outcomes compared to females. However, further randomized controlled trials should be structured to confirm and enforce these conclusions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05819-3.

Fast Functional Rehabilitation Protocol versus Plaster Cast Immobilization Protocol after Achilles Tendon Tenorrhaphy: Is It Different? Clinical, Ultrasonographic, and Elastographic Comparison

BACKGROUND

the incidence of Achilles tendon (AT) rupture is rising; however, there is no clear consensus regarding the optimal treatment. The aim of this retrospective study was to compare instrumental and patient-reported outcome scores after fast functional rehabilitation (group A) versus plaster cast immobilization (group B) programs in patients who underwent AT tenorrhaphy.

METHODS

33 patients, with similar clinical and demographic features, underwent open AT tenorrhaphy between January and July 2018. Of these, 15 patients were treated with fast functional rehabilitation program (group A), and 18 patients were treated with plaster cast immobilization protocol (group B). Sural triceps hypotrophy and functional scores (American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score, and Achilles tendon Total Rupture Score (ATRS)) were recorded at a 12-month follow-up. Ultrasonography (US) and elastosonography (ES) were used to compare the characteristics of the tendons after surgery.

RESULTS

At 12 months, no significant differences in any of the patient-reported outcomes or the instrumental measurement tests were seen between the two groups.

CONCLUSIONS

fast functional rehabilitation after AT surgical repair is safe, effective, and may be the first choice of treatment, especially in young, collaborative, and active patients.

Relative Effect of Extracorporeal Shockwave Therapy Alone or in Combination with Noninjective Treatments on Pain and Physical Function in Knee Osteoarthritis: A Network Meta-Analysis of Randomized Controlled Trials

Extracorporeal shockwave therapy (ESWT) has been recommended for managing pain in patients with knee osteoarthritis (KOA). The difference in therapeutic effects between radial shockwave characteristics (RaSW) and focused shockwave characteristics (FoSW) with different energy levels for KOA remains controversial. The purpose of this network meta-analysis (NMA) was to identify the effects relative to the different ESWT regime and combination treatments on pain and functional outcomes in individuals with KOA. The randomized controlled trials (RCTs) which investigated the efficacy of RaSW, FoSW, and combination treatments in patients with KOA were identified by searches of electronic databases. The included RCTs were analyzed through NMA and risk-of-bias assessment. We analyzed 69 RCTs with a total of 21 treatment arms in the NMA. Medium-energy FoSW plus physical therapy, medium-energy acupoint RaSW plus Chinese medicine, and high-energy FoSW alone were the most effective treatments for reducing pain [standard mean difference (SMD) = -4.51], restoring function (SMD = 4.97), and decreasing joint inflammation (SMD = -5.01). Population area and study quality influenced the treatment outcomes, particularly pain. Our findings indicate that medium-energy ESWT combined with physical therapy or Chinese medicine is beneficial for treating pain and increasing function in adults with KOA.

Combined extracorporeal shockwave therapy and exercise for the treatment of tendinopathy: A narrative review

Tendinopathy is a chronic degenerative musculoskeletal disorder that is common in both athletes and the general population. Exercise and extracorporeal shockwave therapy (ESWT) is among the most common treatments used to mediate tendon healing and regeneration. The review presents the current understanding of mechanisms of action of ESWT and exercise in isolation and briefly synthesises evidence of their effectiveness for various tendinopathies. The central purpose of the review is to synthesize research findings investigating the combination of ESWT and exercise for five common tendinopathies (plantar heel pain, rotator cuff, lateral elbow, Achilles, and patellar tendinopathy) and provide recommendations on clinical applicability. Collectively, the available evidence indicates that ESWT combined with exercise in the form of eccentric training, tissue-specific stretching, or heavy slow resistance training are effective for specific tendinopathies and can therefore be recommended in treatment. Whilst there are at present a limited number of studies investigating combined EWST and exercise approaches, there is evidence to suggest that the combination improves outcomes in the treatment of plantar heel pain, Achilles, lateral elbow, and rotator cuff tendinopathy. However, despite overall positive outcomes in patellar tendinopathy, the combined treatment has not been shown at present to offer additional benefit over eccentric exercise alone.

Efficacy of Extracorporeal Shock Wave Therapy for Lower-Limb Tendinopathy: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

Extracorporeal shock wave therapy, including radial shock wave and focused shock wave types, is widely used for managing tendinopathies. The difference in efficacy between the 2 shock wave characteristics with different dosage levels remains controversial, and the purpose of this meta-analysis was to examine it for patients with lower-limb tendinopathy.

DESIGN

A comprehensive search of online databases and search engines was performed. This study included randomized controlled trials reporting the efficacy of extracorporeal shock wave therapy in treating lower-limb tendinopathy. The included randomized controlled trials were subjected to a meta-analysis and risk of bias assessment.

RESULTS

In total, 29 randomized controlled trials were included, all of which had a good methodological quality, with a PEDro score of ≥6/10. General extracorporeal shock wave therapy showed significant effects at the immediate follow-up [pain score: standardized mean difference = -1.41, 95% confidence interval = -2.01 to -0.82, P < 0.00001; function: standardized mean difference = 2.59, 95% confidence interval = 1.54 to 3.64, P < 0.00001] as well as at 3, 6, and ≥12 months. In sequence, high-dosage focused shock wave, high-dosage radial shock wave, and low-dosage radial shock wave had superior pooled effects on overall clinical outcomes.

CONCLUSIONS

Extracorporeal shock wave therapy exerted a positive overall effect on pain and function for lower-limb tendinopathy. Shock wave types and dosage levels may have different contributions to treatment efficacy.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Describe benefits of extracorporeal shock wave therapy for individuals with lower-limb tendinopathy; (2) Understand the impact of dosing and type of extracorporeal shock wave therapy has on treatment efficacy; and (3) Identify appropriate indications for incorporating extracorporeal shock wave therapy into the treatment plan for patients with lower-limb tendinopathy.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Conservative Rehabilitation Provides Superior Clinical Results Compared to Early Aggressive Rehabilitation for Rotator Cuff Repair: A Retrospective Comparative Study

Background and objectives: To compare the long term clinical outcomes, range of motion (ROM) and strength of two different postoperative rehabilitation protocols after arthroscopic rotator cuff repair (RCR) for full-thickness rotator cuff (RC) tears. Materials and Methods: Patients undergoing RCR were divided into two groups. In 51 patients (56 shoulders), rehabilitation was performed without passive external rotation, anterior elevation ROM, and active pendulum exercises in the first 2 weeks after surgery (Group A). In 49 patients (50 shoulders) aggressive rehabilitation was implemented, with early free passive external rotation, anterior elevation ROM, and active pendulum exercises were allowed from the day after surgery (Group A). Results: No statistically significant differences were found in clinical scores, muscle strength, passive forward flexion, passive and active internal/external rotation between the two groups. However, the mean active forward flexion was 167.3° ± 26° (range 90–180°) in group A and 156.5° ± 30.5° (range 90–180°) in group B (p = 0.04). Conclusions: A statistically significant difference between the 2 groups was found in active forward flexion ROM, which was better in patients of group A.

Clinical efficacy of extracorporeal shockwave therapy for knee osteoarthritis: a systematic review and meta-regression of randomized controlled trials

OBJECTIVE

This study determined the clinical efficacy of extracorporeal shockwave therapy and the predictors of its efficacy for knee osteoarthritis.

DATA SOURCES

Electronic databases and search engines, namely MEDLINE, PubMed, EMBASE, Cochrane Library Database, Physiotherapy Evidence Database (PEDro), China Academic Journals Full-text Database, and Google Scholar, were searched until 5 March 2019, for randomized controlled trials without restrictions on language and publication year.

REVIEW METHODS

Eligible trials and extracted data were identified by two independent investigators. The included articles were subjected to a meta-analysis and risk of bias assessment. Outcomes of interest included treatment success rate, pain, and physical function outcomes. A meta-regression analysis was performed to determine the predictors of treatment outcomes following shockwave therapy.

RESULTS

We included 50 trials (4844 patients) with a median (range) PEDro score of 6 (5-9). Meta-analyses results revealed an overall significant effect favoring shockwave therapy on the treatment success rate (odds ratio 3.22, 95% confidence interval (CI) 2.21-4.69, P < 0.00001; heterogeneity (I²) = 62%), pain reduction (standardized mean difference (SMD) -2.02, 95% CI -2.38 to -1.67, P < 0.00001; I² = 95%), and Western Ontario and McMaster Universities Osteoarthritis Index function outcome (SMD -2.71, 95% CI -3.50 to -1.92, P < 0.00001; I² = 97%). Follow-up duration and energy flux density were independent significant predictors of shockwave efficacy.

CONCLUSION

Shockwave therapy is beneficial for knee osteoarthritis. Shockwave dosage, particularly the energy level and intervention duration, may have different contributions to treatment efficacy.

Comparison of the Effect of 5 Different Treatment Options for Managing Patellar Tendinopathy: A Secondary Analysis

OBJECTIVE

Currently, no treatments exist for patellar tendinopathy (PT) that guarantee quick and full recovery. Our objective was to assess which treatment option provides the best chance of clinical improvement and to assess the influence of patient and injury characteristics on the clinical effect of these treatments.

DESIGN

A secondary analysis was performed on the combined databases of 3 previously performed double-blind randomized controlled trials.

PATIENTS

In total, 138 patients with PT were included in the analysis.

INTERVENTIONS

Participants were divided into 5 groups, based on the treatment they received: Extracorporeal shockwave therapy (ESWT) (n = 31), ESWT plus eccentric training (n = 43), eccentric training (n = 17), topical glyceryl trinitrate patch plus eccentric training (n = 16), and placebo treatment (n = 31).

MAIN OUTCOME MEASURES

Clinical improvement (increase of ≥13 points on the Victorian Institute of Sport Assessment-Patella score) after 3 months of treatment.

RESULTS

Fifty-two patients (37.7%) improved clinically after 3 months of treatment. Odds ratios (ORs) for clinical improvement were significantly higher in the eccentric training group (OR 6.68, P = 0.009) and the ESWT plus eccentric training group (OR 5.42, P = 0.015) compared with the other groups. We found evidence that a high training volume, a longer duration of symptoms, and older age negatively influence a treatment's clinical outcome (trend toward significance).

CONCLUSIONS

Our study confirmed the importance of exercise, and eccentric training in particular, in the management of PT. The role of ESWT remains uncertain. Further research focusing on the identified prognostic factors is needed to be able to design patient-specific treatment protocols for the management of PT.

Use of artificial neural networks to identify the predictive factors of extracorporeal shock wave therapy treating patients with chronic plantar fasciitis

The purpose of our study is to identify the predictive factors for a minimum clinically successful therapy after extracorporeal shock wave therapy for chronic plantar fasciitis. The demographic and clinical characteristics were evaluated. The artificial neural networks model was used to choose the significant variables and model the effect of achieving the minimum clinically successful therapy at 6-months’ follow-up. The multilayer perceptron model was selected. Higher VAS (Visual Analogue Score) when taking first steps in the morning, presence of plantar fascia spur, shorter duration of symptom had statistical significance in increasing the odd. The artificial neural networks model shows that the sensitivity of predictive factors was 84.3%, 87.9% and 61.4% for VAS, spurs and duration of symptom, respectively. The specificity 35.7%, 37.4% and 22.3% for VAS, spurs and duration of symptom, respectively. The positive predictive value was 69%, 72% and 57% for VAS, spurs and duration of symptom, respectively. The negative predictive value was 82%, 84% and 59%, for VAS, spurs and duration of symptom respectively. The area under the curve was 0.738, 0.882 and 0.520 for VAS, spurs and duration of symptom, respectively. The predictive model showed a good fitting of with an overall accuracy of 92.5%. Higher VAS symptomatized by short-duration, severer pain or plantar fascia spur are important prognostic factors for the efficacy of extracorporeal shock wave therapy. The artificial neural networks predictive model is reasonable and accurate model can help the decision-making for the application of extracorporeal shock wave therapy.

Efficacy of extracorporeal shock wave therapy for knee tendinopathies and other soft tissue disorders: a meta-analysis of randomized controlled trials

Background

Extracorporeal shock-wave therapy (ESWT), which can be divided into radial shock-wave therapy (RaSWT) and focused shock-wave therapy (FoSWT), has been widely used in clinical practice for managing orthopedic conditions. The aim of this study was to determine the clinical efficacy of ESWT for knee soft tissue disorders (KSTDs) and compare the efficacy of different shock-wave types, energy levels, and intervention durations.

Methods

We performed a comprehensive search of online databases and search engines without restrictions on the publication year or language. We selected randomized controlled trials (RCTs) reporting the efficacy of ESWT for KSTDs and included them in a meta-analysis and risk of bias assessment. The pooled effect sizes of ESWT were estimated by computing odds ratios (ORs) with 95% confidence intervals (CIs) for the treatment success rate (TSR) and standardized mean differences (SMDs) with 95% CIs for pain reduction (i.e., the difference in pain relief, which was the change in pain from baseline to the end of RCTs between treatment and control groups) and for restoration of knee range of motion (ROM).

Results

We included 19 RCTs, all of which were of high or medium methodological quality and had a Physiotherapy Evidence Database score of ≥5/10. In general, ESWT had overall significant effects on the TSR (OR: 3.36, 95% CI: 1.84–6.12, P < 0.0001), pain reduction (SMD: − 1.49, 95% CI: − 2.11 to − 0.87, P < 0.00001), and ROM restoration (SMD: 1.76, 95% CI: 1.43–2.09, P < 0.00001). Subgroup analyses revealed that FoSWT and RaSWT applied for a long period (≥1 month) had significant effects on pain reduction, with the corresponding SMDs being − 3.13 (95% CI: − 5.70 to − 0.56; P = 0.02) and − 1.80 (95% CI: − 2.52 to − 1.08; P < 0.00001), respectively. Low-energy FoSWT may have greater efficacy for the TSR than high-energy FoSWT, whereas the inverse result was observed for RaSWT.

Conclusions

The ESWT exerts an overall effect on the TSR, pain reduction, and ROM restoration in patients with KSTDs. Shock-wave types and application levels have different contributions to treatment efficacy for KSTDs, which must be investigated further for optimizing these treatments in clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2204-6) contains supplementary material, which is available to authorized users.

Comparison Between Extracorporeal Shock Wave Therapy and Intra-articular Hyaluronic Acid Injections in the Treatment of First Carpometacarpal Joint Osteoarthritis

Objective

To compare extracorporeal shockwave therapy (ESWT) with hyaluronic acid (HA) intra-articular injections in terms of pain relief, improvement in hand function, and strength in subjects with first carpometacarpal (CMC) joint osteoarthritis.

Methods

Fifty-eight patients received either focused ESWT or HA injection once a week for 3 consecutive weeks. In the ESWT group, 2,400 consecutive pulses were performed during each treatment session using a frequency of 4 Hz and an energy flux density of 0.09 mJ/mm². The HA group underwent one cycle of three injections of 0.5 cm³ HA. The main outcome measures were pain and hand function as measured by the visual analogue scale (VAS) and Duruoz Hand Index (DHI), respectively. The secondary outcomes were grip and pinch strength. Each assessment was performed at baseline, at the end of treatment, and at 3- and 6-month follow-up visits.

Results

According to VAS and DHI scores, a significant change in test performance was observed over time in both groups (p<0.001), with a greater average improvement in painful symptomatology at the 6-month follow-up in the ESWT group. A significant improvement in strength was observed in both groups, but the ESWT group showed better results on the pinch test starting immediately at the end of treatment.

Conclusion

The use of ESWT in patients with first CMC joint osteoarthritis leads to a reduction in pain, an improvement in pinch test performance that persists for at least 6 months, and a decrease in hand disability up to the 6-month follow-up visit.

Deltoid muscle tropism does not influence the outcome of arthroscopic rotator cuff repair

BACKGROUND

Several different factors have been identified as causes of failure of rotator cuff (RC) repair. However, no studies focused on the role of the deltoid muscle. The aim of this study was to investigate the role of the deltoid tropism in the outcomes of arthroscopic RC repair procedures.

MATERIALS AND METHODS

Nine male (45 %) and 11 female (55 %) patients who underwent arthroscopic RC repair were included in the study. The mean age was 63.5 ± 8.1 years (range 50-74 years), and the follow-up averaged 1.9 ± 1.3 years (range 1-5 years) after surgery. Clinical outcomes were assessed using the modified University of California, Los Angeles (UCLA) shoulder rating scale, Wolfgang criteria shoulder score and Oxford shoulder score (OSS). Functional outcomes were evaluated considering active and passive range of motion of the shoulder and muscle strength. The deltoid tropism was measured pre-operatively and post-operatively using T2-weighted transverse MRI images.

RESULTS

No statistically significant correlation was found between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the UCLA shoulder rating scale, Wolfgang shoulder score and OSS. At the same time, no statistically significant relationship was detected between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the functional outcomes.

CONCLUSIONS

The deltoid tropism does not influence the results of arthroscopic RC repair. Early RC repair may prevent the reduction in the tropism of the deltoid muscle. Nevertheless, further prospective randomized studies with larger samples are necessary to clarify the role of deltoid tropism in the outcomes of arthroscopic RC repair procedures.