The puzzling pathophysiology of frozen shoulders - a scoping review

Differences in biomechanical and metabolic factors between patients with frozen shoulder and asymptomatic individuals. A cross-sectional study

BACKGROUND

the pathogenesis of frozen shoulder (FS) is thought to be one of inflammation and fibrosis possibly influenced by hyperglycemia. Biomechanical changes of the shoulder joint in terms of muscle strength, scapular kinematics and proprioception might occur in FS.

OBJECTIVES

to compare muscle strength, scapular kinematics, proprioception, and blood glucose levels within patients with FS and to asymptomatic individuals.

DESIGN

cross-sectional study.

METHOD

Thirty-five patients with FS and 35 asymptomatic age and gender-matched individuals underwent physical assessment to determine muscle strength (abduction, external and internal rotation), scapular kinematics (both visually and with a plurimeter), proprioception (joint position sense), and blood glucose level.

RESULTS

Patients with FS showed a decrease in muscle strength in their affected shoulder compared to both the unaffected shoulder and asymptomatic individuals. Significant differences were found between the affected and unaffected shoulder in the FS group and between groups (FS versus controls) in scapular upward rotation (plurimeter) at 30° and 60° abduction. No difference in scapular kinematics (visual observation), proprioception, and blood glucose levels was found neither between shoulders in the FS group nor between groups.

CONCLUSION

A clinically relevant difference in muscle strength and increase in scapular upward rotation were found in the affected shoulder of patients with FS compared to their unaffected side and controls. However, no evidence of different levels of scapular kinematics (visual observation), proprioception, and blood glucose levels in the affected shoulder compared to the unaffected shoulder or controls is lacking.

Risk factors and predictive models for frozen shoulder

This study aims to explore the risk factors associated with frozen shoulder (FS) and develop a predictive model for diagnosing FS, in order to facilitate early detection of the condition. A total of 103 patients diagnosed with FS and admitted to the Department of Joint Surgery at Suining Central Hospital between October 2021 and October 2023 were consecutively included in the study. Additionally, 309 individuals without shoulder joint diseases, matched for age and gender, who visited the department during the same time, were included as the control group.The complete recording of clinical data for all patients was followed by the utilization of statistical tests such as the Mann-Whitney U test, sample t test, and chi-square test to compare different groups. Additionally, multivariate binary logistic regression analysis was employed to identify risk factors associated with the occurrence of FS in patients, leading to the establishment of a prediction model and derivation of a simplified equation. The diagnostic effectiveness of individual indicators and prediction models was assessed through the use of receiver operating characteristic (ROC) curve analysis. In the sample of 103 individuals, 35 were identified as male and 68 as female, with an average age range of 40-70 years (mean age: 54.20 ± 6.82 years). The analysis conducted between different groups revealed that individuals with a low body mass index (BMI), in conjunction with other factors such as diabetes, cervical spondylosis, atherosclerosis, and hyperlipidemia, were more susceptible to developing FS. Logistic regression analysis further indicated that low BMI, diabetes, cervical spondylosis, and hyperlipidemia were significant risk factors for the occurrence of FS. These variables were subsequently incorporated into a predictive model, resulting in the creation of a simplified equation.The ROC curve demonstrated that the combined indicators in the predictive model exhibited superior diagnostic efficacy compared to single indicators, as evidenced by an area under the curve of 0.787, sensitivity of 62.1%, and specificity of 82.2%. Low BMI, diabetes, cervical spondylosis, and hyperlipidemia are significant risk factors associated with the occurrence of FS. Moreover, the utilization of a prediction model has demonstrated superior capability in forecasting the likelihood of FS compared to relying solely on individual indicators. This finding holds potential in offering valuable insights for the early diagnosis of FS.

Gene association analysis to determine the causal relationship between immune-mediated inflammatory diseases and frozen shoulder

Multiple studies have indicated a potential correlation between immune-mediated inflammatory diseases (IMIDs) and Frozen shoulder (FS). To explore the genetic causal relationship between IMIDs and FS using 2-sample Mendelian randomization (MR) analysis. Genome-wide association study (GWAS) summary data for FS were obtained from Green's study, while data for 10 IMIDs were sourced from the FinnGen Consortium. The MR analysis was performed using inverse variance weighting, MR Egger, and weighted median methods. IVW, as the primary MR analysis technique, was complemented with other sensitivity analyses to validate the robustness of the results. Additionally, reverse MR analysis was further conducted to investigate the presence of reverse causal relationships. In the forward MR analysis, genetically determined 4 IMIDs are causally associated with FS: rheumatoid arthritis (odds ratio [OR] (95% confidence interval [95% CI]) = 1.05 [1.02-1.09], P < .01); type 1 diabetes (OR [95% CI] = 1.06 [1.03-1.09], P < .01); hypothyroidism (OR [95% CI] = 1.07 [1.01-1.14], P = .02); and Celiac disease (OR [95% CI] = 1.02 [1.01-1.04], P = .01). However, no causal relationship was found between 6 IMIDs (autoimmune hyperthyroidism, Crohn disease, ulcerative colitis, psoriasis, sicca syndrome and systemic lupus erythematosus) and FS. Sensitivity analyses did not detect any heterogeneity or horizontal pleiotropy. In the reverse MR analysis, no causal relationship was observed between FS and IMIDs. In conclusion, this MR study suggests a potential causal relationship between rheumatoid arthritis, type 1 diabetes, hypothyroidism, and Celiac disease in the onset and development of FS. Nevertheless, more basic and clinical research will be needed in the future to support our findings.

Psychometric properties of the Disability of Arm Shoulder and Hand (DASH) in subjects with frozen shoulder: a reliability and validity study

BACKGROUND

Frozen Shoulder (FS) is a painful condition characterized by severe pain and progressive restriction of shoulder movement, leading to functional impairment and reduced quality of life. While different Patient Reported Outcome Measurements (PROMs) tools exist for assessing shoulder diseases, few specific PROMs are validated for FS patients.

PURPOSE

This study aims to assess the psychometric properties of the Disability of Arm, Shoulder, and Hand (DASH) questionnaire in FS patients.

METHODS

One hundred and twenty-four subjects (mean ± SD age = 55.4 ± 7.9 years; 55.6% female) diagnosed with FS were included and completed the DASH questionnaire, the Numerical Pain Rating Scale (NPRS), the Shoulder Pain and Disability Index (SPADI), and the Short-Form Health Survey 36 (SF-36). Floor or ceiling effects were investigated. Structural validity was analysed through a unidimensional Confirmatory Factor Analysis (CFA), internal consistency through Cronbach's alpha, test-retest reliability through the Intraclass Correlation coefficient (ICC), measurement error through the Standard Error of Measurement (SEM), and the Minimum Detectable Change (MDC), and construct validity through the hypothesis testing with the correlation with the other outcome measures used.

RESULTS

No floor or ceiling effects were observed. CFA confirmed a one-factor structure after addressing local item dependency (Root Mean Square Error of Approximation = 0.055; Standardized Root Mean Square Residual = 0.077; Comparative Fit Index = 0.970; Tucker-Lewis Index = 0.968). Cronbach's alpha was high (= 0.951), and test-retest reliability was excellent (ICC = 0.999; 95% CI: 0.998-1.000). SEM was equal to 0.5 points, and MDC to 1.5 points. Construct validity was considered satisfactory as 80% of the a-priori hypotheses were met.

CONCLUSION

The DASH questionnaire demonstrated good psychometric properties in FS patients, supporting its use as a valuable tool for assessing the impact of FS in clinical and research settings.

Evidence for Combining Conservative Treatments for Adhesive Capsulitis

Background: Adhesive capsulitis, also known as frozen shoulder, is a challenge to treat clinically. Common first-line treatment options are suprascapular nerve block (SSNB), intra-articular corticosteroid (IACS) injection, hydrodilatation, and physical therapy. This literature review summarizes each of these conservative treatments and discusses the evidence base for combining treatment options for potential additive benefits to improve patient outcomes (ie, pain, range of motion [ROM], and shoulder function). Methods: The PubMed and Google Scholar databases were searched using the search terms "adhesive capsulitis," "frozen shoulder," "corticosteroids," "physical therapy," "suprascapular nerve block," "hydrodilatation," and "conservative care." Pertinent articles were identified and synthesized to provide a comprehensive review of 4 common conservative treatments for adhesive capsulitis. Results: Combining SSNB with physical therapy and/or IACS injection and combining IACS injection with physical therapy have support in the literature for improving shoulder pain, ROM, and function, while hydrodilatation and physical therapy seem to offer some additive benefits for improving shoulder ROM when used as adjunct treatments for adhesive capsulitis. Conclusion: Adhesive capsulitis remains a challenge to treat clinically with much still unknown regarding treatment optimization. For the foreseeable future, first-line conservative management will continue to be the mainstay of managing adhesive capsulitis. Thus, knowing how to best use and optimize these various options-both individually and in combination-is vital for effective treatment.

The diagnostic value of physical examination tests in adhesive capsulitis: a systematic review

INTRODUCTION

Adhesive capsulitis, a condition marked by pain and stiffness of the shoulder, can have a frustrating clinical course for patients and health care professionals. Despite huge research interest, a universally accepted and used definition of clinical criteria for the diagnosis of adhesive capsulitis is currently still lacking. This systematic review aimed to identify diagnostic values for clinical examinations tests used in the diagnosis of adhesive capsulitis.

EVIDENCE ACQUISITION

A total of 5 electronic databases (PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials [CENTRAL] and PEDro) were searched for relevant studies from 2002 until October 2022 using the terms: "adhesive capsulitis AND diagnosis" and "frozen shoulder AND diagnosis." The Downs and Black Checklist (modified) was used to assess the risk of bias. The study protocol was prospectively registered at the International prospective register of systematic reviews (PROSPERO, CRD42022365993).

EVIDENCE SYNTHESIS

The initial database search identified 1799 studies, of which 9 (0.50%) were eventually included in the systematic review. Non-intrusive shoulder range of motion measurements in patients with adhesive capsulitis using the Kinect for Windows (Microsoft, Redmond, WA, USA) showed high correlation with clinical range of motion measurement. Two specific clinical tests, the affected-unaffected shoulder approach of the Coracoid Pain Test and the Distension Test in Passive External Rotation, were identified and presented excellent sensibility and specificity in the diagnosis of adhesive capsulitis, in their original study. Comparison between clinical tests was not possible due to the heterogeneity in clinical tools.

CONCLUSIONS

This systematic review identified several physical examination tests developed for the diagnosis of adhesive capsulitis but could not compare them nor advance a set of clinical diagnostic tests that are scientifically validated. Further research is warranted to obtain validation of clinical diagnosis tools for adhesive capsulitis.

The incidence of adhesive capsulitis and COVID-19 pandemic effect

Background

There are multiple pieces of evidence in the literature that coronavirus disease 2019 (COVID-19) has a pronounced effect on physiological health. There is little existing literature that has studied the pandemic's impact on adhesive capsulitis (AC) incidence. This study aimed to compare the incidence of primary AC before and during the pandemic.

Methods

A retrospective cohort study was done to establish the incidence of primary AC during the COVID-19 pandemic, from March 2020 to March 2021, the pandemic period, and from March 2019 to March 2020, the control period. During these periods, all patients diagnosed with primary AC were included. Patients were also categorized into three different treatment groups according to corticosteroid injection status (none, 1 injection, and 2 injections). The waiting time for the appointment was calculated as a possible confounding factor. Statistical analysis used the chi-square for categorical variables and the Student t test for continuous variables.

Results

There were 69 patients diagnosed with primary AC out of 704 new referrals during the pandemic. One year earlier, a total of 73 patients were diagnosed with primary AC out of 1148 new referrals. Representing a relative increase of 3.5% (P = .086) in the incidence of primary AC. No significant differences were found between the control and the pandemic groups in regard to the distribution of patients per treatment group (P = .13), age (P = .49), sex (P = .21), laterality (P = .54), diabetic disease (P = .45), and thyroid disease (P = .62).

Conclusion

There was a nonstatistically significant increase in the incidence of primary AC during the COVID-19 pandemic. No other significant differences were found. Further research is still needed to evaluate the relationship between the COVID-19 pandemic and AC.

Exploration of the clinical course and longitudinal correlations in frozen shoulder: The role of autonomic function, central pain processing, and psychological variables. A longitudinal multicenter prospective observational study

BACKGROUND

Altered central pain processing (CPP) and dysautonomia might play a role in the clinical course of frozen shoulder and psychological factors, like pain catastrophizing and hypervigilance, might influence clinical variables in frozen shoulder.

OBJECTIVES

To explore the clinical course of frozen shoulder regarding CPP, dysautonomia, pain catastrophizing, and hypervigilance and to explore whether longitudinal correlations between these outcomes and pain intensity were present.

DESIGN

prospective longitudinal observational study.

METHOD

Participants with frozen shoulder were recruited at hospitals and general practitioner practices and followed for 9 months. They completed six questionnaires (about demographics, shoulder pain and disability, pain intensity, pain catastrophizing, pain hypervigilance, and autonomic symptoms) and underwent tactile sensitivity (allodynia), pressure pain thresholds (hyperalgesia), temporal summation, and conditioned pain modulation during four timeframes (3-month intervals).

RESULTS

Initially, 149 participants with frozen shoulder were recruited and 88 completed all the measurements. An improvement from baseline to at least one follow-up measurement was found for shoulder pain and disability, pain intensity, pain catastrophizing, hypervigilance, and dysautonomia. A fair longitudinal correlation was found between pain intensity and catastrophizing and hypervigilance (r = 0.301-0.397). Poor longitudinal correlations were found between pain intensity and allodynia and hyperalgesia (r = -0.180-0.193), between pain catastrophizing and dysautonomia (r = 0.209) and between hypervigilance and hyperalgesia (r = -0.159).

CONCLUSION

Patients with frozen shoulder showed an early improvement that flattened with time in several pain and psychological variables over the course of 9 months. However, autonomic symptoms rather showed a late improvement over 9 months.

Salvianolic acid B attenuates inflammation and prevent pathologic fibrosis by inhibiting CD36-mediated activation of the PI3K-Akt signaling pathway in frozen shoulder

Frozen shoulder (FS) is characterized by pain and limited range of motion (ROM). Inflammation and fibrosis are accepted as main pathologic processes associated with the development of FS. However, the intrinsic mechanisms underlying pathologic fibrosis remain unclear. We aimed to elucidate the key molecules involved in pathologic fibrosis and explore new therapeutic targets for FS. Synovial fibroblasts isolated from patient biopsies were identified using immunofluorescence. Western blotting, RT-qPCR, cell adhesion tests, and would-healing assays were used to evaluate the fibrosis-related functions of synovial fibroblasts. Elevated cluster of differentiation 36 (CD36) expression was detected in FS using Western blotting and immunohistochemistry. Salvianolic acid b (SaB) inhibited CD36, blocking synovial fibroblast-induced inflammation and fibrosis. Our RNA-seq data showed that knocking down CD36 dramatically impaired the capacity of synovial fibroblasts for cell adhesion and that the PI3K-Akt signaling pathway may be crucial to the fibrotic process of FS. By up-regulating CD36 and inhibiting the phosphorylation of Akt, we demonstrated that CD36 promotes pathologic fibrosis by activating the PI3k-Akt pathway. Finally, rats treated with SaB had improved ROM and less collagen fiber deposition than the FS model group. Conclusion: SaB attenuates inflammation and inhibited the CD36-mediated activation of the PI3K-Akt signaling pathway to block pathologic fibrosis of FS in vitro and in vivo models.

Exploration of the clinical course of frozen shoulder: A longitudinal multicenter prospective study of functional impairments

BACKGROUND

Contradictory evidence exists regarding the clinical course of frozen shoulder (FS).

OBJECTIVES

To explore the clinical course of FS regarding disabilities, pain, range of motion (ROM), muscle strength, scapular upward rotation, and proprioception and to establish longitudinal correlations between these variables.

METHODS

Patients with FS were prospectively followed for 9 months at 3-month intervals. Assessment included the Disabilities of the Arm, Shoulder and Hand questionnaire; visual analogue scale for pain; an inclinometer for shoulder external rotation (ER), internal rotation (IR), flexion, and abduction ROM, and scapular upward rotation and proprioception, as well as handheld dynamometry for muscle strength in shoulder abduction, ER, and IR.

RESULTS

Initially, 149 patients (98 females; mean (SD) age 53 (9) years) were included, with 88 completing all follow-up assessments. Most variables showed early improvement in the clinical course of FS, particularly ER and IR at 90° abduction, which continued to improve from 6 to 9 months of follow-up. Associations were observed between disabilities and pain (r = 0.61), disabilities/pain and ROM (r=-0.62 to -0.59 and r=-0.47 to -0.39, respectively), disabilities/pain and muscle strength (r=-0.24 to -0.35 and r=-0.36 to -0.17, respectively), and between disabilities/pain and scapular upward rotation below shoulder level (r = 0.23 to 0.38 and r = 0.24 to 0.30, respectively). ROM correlated with muscle strength (r = 0.14 to 0.44), while both ROM and ER muscle strength correlated with scapular upward rotation below shoulder level (r=-0.37 to -0.23 and r=-0.17 to -0.12, respectively). Muscle strength correlated with scapular upward rotation above shoulder level (r = 0.28 to 0.38) and lift-off muscle strength correlated with joint repositioning (r=-0.17 to -0.15).

CONCLUSION

Almost all factors improved in the early phase (3-6 months) after baseline assessment, while ER and IR ROM at shoulder level continued to improve long term.

Is there any benefit of adding a central nervous system-focused intervention to a manual therapy and home stretching program for people with frozen shoulder? A randomized controlled trial

BACKGROUND

Frozen shoulder (FS) is a highly disabling pathology of poorly understood etiology, which is characterized by the presence of intense pain and progressive loss of range of motion. The aim of this study was to evaluate the effect of adding a central nervous system (CNS)-focused approach to a manual therapy and home stretching program in people with FS.

METHODS

A total of 34 patients with a diagnosis of primary FS were randomly allocated to receive a 12-week manual therapy and home stretching program or manual therapy and home stretching program plus a CNS-focused approach including graded motor imagery and sensory discrimination training. The Shoulder Pain and Disability Index score, self-perceived shoulder pain (visual analog scale score), shoulder range of motion, and the Patient-Specific Functional Scale score were measured at baseline, after a 2-week washout period just before starting treatment, after treatment, and at 3 months' follow-up.

RESULTS

No significant between-group differences in any outcome were found either after treatment or at 3 months' follow-up.

CONCLUSION

A CNS-focused approach provided no additional benefit to a manual therapy and home stretching program in terms of shoulder pain and function in people with FS.

Suprascapular Nerve Block (SSNB) improves the outcome in exercise based management of Primary Adhesive Capsulitis (PAC): A prospective randomized comparative study

Background and Aims

Increased pain and associated stiffness hinders the advantages of exercise and process of recovery in primary adhesive capsulitis. We hypothesized that suprascapular nerve block may positively affect the outcome due to its role in pain relief of acute or chronic shoulder pain. We compared the effect of suprascapular nerve block and exercise with only exercise on the recovery of primary adhesive capsulitis.

Material and Methods

A total of 96 patients of both sexes presenting with primary adhesive capsulitis were divided by computer randomization in two equal groups (n = 48). Group A received exercise only and Group B received suprascapular nerve block followed by exercise. Oral paracetamol was given for analgesia as desired. Patients were followed up at 4, 8, 16, and 24 weeks. Pain was assessed by visual analog scale; functional outcome by Shoulder Pain and Disability Index and range of movement by goniometer.

Results

The pain scores and Shoulder Pain and Disability Index scores were significantly lower at all observation points of 4, 8,16, and 24 weeks in Group B than Group A (P < 0.05). The range of movement in all the ranges of forward flexion, extension, internal and external rotation, and abduction at all observation points was significantly higher in Group-B (P < 0.05) compared to Group A. The consumption of analgesics was significantly more in Group A than Group B at 4 and 8 weeks (P = 0.020 and P = 0.044) but comparable at 12 and 24 weeks (P = 0.145 and P = 0.237 respectively).

Conclusion

Combining SSNB with exercise is more effective in treatment of primary adhesive capsulitis than exercise alone and reduces the use of analgesics. SSNB it is effective and safe to use in primary adhesive capsulitis.

Cytokines' Role in the Pathogenesis and Their Targeting for the Prevention of Frozen Shoulder: A Narrative Review

Frozen shoulder (FS) is a common name for shoulder movement limitation with different degrees of shoulder rigidity and pain. It is characterized by varying developmental courses, different levels of shoulder movement limitation, and background ambiguity due to the multiplicity of its causative factors. Systemic inflammatory cytokines monitoring and restraining is easy to apply, fast to conduct, and needs lower costs compared to invasive methods for frozen shoulder stage evaluation and early controlling of its progress to the stage that necessitates surgical intervention. The aim of this review was to assess the recent findings concerning the role of cytokines in FS pathogenesis and the possibility of preventing or controlling their progress through targeting these cytokines by the new drugs candidates, such as hyaluronan (HA), botulinum toxin type A (BoNT A), Tetrandrine, tumor necrosis factor-stimulated gene-6 (TSG-6), and cannabidiol. Searching the PubMed site, we encountered out of 1608 records, from which 16 original studies were included for the quantitative construction of this systematic review screening of the recent studies to investigate the different FS pathogenic pathways. Most of the scenarios are centered around the inflammatory and fibrotic process triggered by synovial and capsular fibroblast stimulation. This mechanism depends mainly on alarmins cytokines, including thymic stromal lymphopoietin (TSLP), interleukin-33 (IL-33), and interleukin-25 (IL-25), with the stimulation of interleukin-1 α (IL-1α), interleukin-1 β (IL-1β), tumor necrosis alpha (TNF-α), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in a joint capsule. Different pathways of transforming growth factor- β (TGF-β) stimulation, resulting in overexpression of the fibrotic factors as tenascin C (TNC), fibronectin 1, collagen I (COL 1) and collagen III (COL III), and matrix metalloproteinases (MMPs) in the capsular or synovial/capsular fibroblasts. The overall investigation of these studies led us to conclude that the new drug candidates proved their efficiency in controlling the common pathogenesis of the inflammatory and fibrotic pathways of frozen shoulder and therefore represent a prospect for easy and early controlling and efficiently treating this serious disease.

Managing painful shoulder after neurological injury

Shoulder pain is common after neurological injury and can be disabling, lead to poor functional outcomes and increase care costs. Its cause is multifactoral and several pathologies contribute to the presentation. Astute diagnostic skills and a multidisciplinary approach are required to recognise what is clinically relevant and to implement appropriate stepwise management. In the absence of large clinical trial data, we aim to provide a comprehensive, practical and pragmatic overview of shoulder pain in patients with neurological conditions. We use available evidence to produce a management guideline, taking into account specialty opinions from neurology, rehabilitation medicine, orthopaedics and physiotherapy.

Ultrasound-guided glenohumeral joint injections for shoulder pain in ALS: A case series

Introduction

Shoulder pain is a common secondary impairment for people living with ALS (PALS). Decreased range of motion (ROM) from weakness can lead to shoulder pathology, which can result in debilitating pain. Shoulder pain may limit PALS from participating in activities of daily living and may have a negative impact on their quality of life. This case series explores the efficacy of glenohumeral joint injections for the management of shoulder pain due to adhesive capsulitis in PALS.

Methods

People living with ALS and shoulder pain were referred to sports medicine-certified physiatrists for diagnostic evaluation and management. They completed the Revised ALS Functional Rating Scale and a questionnaire asking about their pain levels and how it impacts sleep, function, and quality of life at baseline pre-injection, 1-week post-injection, 1 month post-injection, and 3 months post-injection.

Results

We present five cases of PALS who were diagnosed with adhesive capsulitis and underwent glenohumeral joint injections. Though only one PALS reported complete symptom resolution, all had at least partial symptomatic improvement during the observation period. No complications were observed.

Conclusions

People living with ALS require a comprehensive plan to manage shoulder pain. Glenohumeral joint injections are safe and effective for adhesive capsulitis in PALS, but alone may not completely resolve shoulder pain. Additional therapies to improve ROM and reduce pain should be considered.

Current concepts in the diagnosis and treatment of adhesive capsulitis: role of diagnostic imaging and ultrasound-guided interventional procedures

Adhesive capsulitis is a common cause of painful shoulder, characterized by pain and restricted range of motion of the glenohumeral joint. With a well-known clinical presentation, and an increasing understanding of its clinical and radiologic features, early diagnosis of adhesive capsulitis is becoming a reality. Although often treated conservatively, for refractory cases arthroscopic release and open capsulotomy have been the only therapeutic option for a long time. Therefore, in the last years, a particular effort was put into the development of novel minimal-invasive techniques capable of pain relief and functional range improvement of the glenohumeral joint. The purpose of this literature review is to report the main updates on diagnosis and treatment for adhesive capsulitis with a focus on imaging diagnosis techniques and novel minimally invasive ultrasound-guided treatments. Results showed that ultrasound-guided procedures come with a high success rate in terms of pain reduction and improved range of motion, thus making the ultrasound a unique tool capable of giving the operator real-time diagnostic information confirming the clinical suspicion, and subsequently performing an interventional procedure.

Frozen shoulder

Frozen shoulder is a common debilitating disorder characterized by shoulder pain and progressive loss of shoulder movement. Frozen shoulder is frequently associated with other systemic conditions or occurs following periods of immobilization, and has a protracted clinical course, which can be frustrating for patients as well as health-care professionals. Frozen shoulder is characterized by fibroproliferative tissue fibrosis, whereby fibroblasts, producing predominantly type I and type III collagen, transform into myofibroblasts (a smooth muscle phenotype), which is accompanied by inflammation, neoangiogenesis and neoinnervation, resulting in shoulder capsular fibrotic contractures and the associated clinical stiffness. Diagnosis is heavily based on physical examination and can be difficult depending on the stage of disease or if concomitant shoulder pathology is present. Management consists of physiotherapy, therapeutic modalities such as steroid injections, anti-inflammatory medications, hydrodilation and surgical interventions; however, their effectiveness remains unclear. Facilitating translational science should aid in development of novel therapies to improve outcomes among individuals with this debilitating condition.

The impact of the COVID-19 pandemic on frozen shoulder incidence rates and severity

BACKGROUND

Although there is evidence that the COVID-19 pandemic had profound physiological and psychological effects, there is no research aimed at understanding if the pandemic has had an impact on the incidence or severity of frozen shoulder (FS). The aim of this study was to compare the incidence and severity of idiopathic FS before and during the pandemic.

METHODS

A retrospective cohort study was performed to establish the incidence of FS during the pandemic, from March 2020 to January 2021 (pandemic study period), compared to the same time period 1 year earlier, before the pandemic (control group). All patients who were diagnosed with idiopathic FS were included. To assess the severity of the condition, visual analog scale (VAS) for pain score and Subjective Shoulder Value (SSV) on presentation were recorded and the patients were categorized into 5 different treatment groups (0 injections, 1 injection, 2 injections, 3 injections, or capsular release). As the pandemic and public health restrictions could have influenced the availability of appointments, the waiting time between referral and first appointment was calculated as a possible confounding factor. Statistical analysis was performed using the chi-square and Student t test for categorical and continuous variables, respectively.

RESULTS

There were 847 new patient consultations during the pandemic study period; of these, 232 were for idiopathic FS. One year earlier, there were 898 initial consultations for a new shoulder problem; of these, 176 were for idiopathic FS. This represents a relative increase of 39.8% (P < .001) in the incidence of patients with FS. The mean SSV in the control group was 50% ± 20% vs. 45% ± 18% in the pandemic group-statistically significant (P = .013) but unlikely to be clinically significant. The VAS pain score was similar in both groups: mean 6 ± 2 and 7 ± 2, respectively (P = .06). There was no significant difference between the control and the pandemic group in the distribution of patients per treatment group (P = .94). The mean waiting time from referral to appointment was not significantly different between the control and the pandemic group: 58 ± 30 days vs. 55 ± 27 days (P = .30).

CONCLUSION

During the COVID-19 pandemic, there was a significant increase in the incidence of patients with FS. No significant difference in severity was observed. Further research is needed to evaluate a causal relationship between the COVID-19 pandemic and FS.

Effect of manipulation technique using ultrasound-guided cervical nerve root block on range of motion at the shoulder joint in frozen shoulder: a retrospective study

Purpose

The aim of this study was to evaluate the range of motion (ROM) at the shoulder joint before and after silent manipulation.

Methods

This retrospective study included all patients who underwent silent manipulation at our institution between January 2013 and December 2017. In total, 1,665 shoulders in 1,610 patients (519 men, 1,146 women; mean age 55.4 ± 8.8 years) were treated during the study period. The mean symptom duration was 6.6 ± 7.1 months. ROM at the shoulder joint was measured in flexion, abduction, and external rotation before silent manipulation and at 1 week and 1, 2, and 3 months after the procedure.

Results

Mean ROM at the shoulder was 98.8° (95% confidence interval [CI] 97.9–99.8) before silent manipulation and 155.5° (154.1–156.8) after 3 months in flexion (p = 0.0000), 75.6° (74.5–76.8) and 152.9° (151.0–154.9), respectively, in abduction (p = 0.0000), and 12.7° (12.0–13.4) and 45.9° (44.4–47.4) in external rotation (p = 0.0000). All ROM values were significantly increased at all time points after the procedure. There were no unanticipated adverse events or serious adverse reactions.

Conclusions

This study reports on the efficacy and safety of manipulation using conduction anesthesia for shoulder contractures in a large group of patients. Silent manipulation can increase ROM at the shoulder safely and effectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00500-z.

Radial shock-wave therapy for frozen shoulder patients with type 2 diabetes mellitus: a pilot trial comparing two different energy levels

BACKGROUND

Extracorporeal shock-wave therapy (ESWT) is highly recommended for the management of orthopedic shoulder pathologies. Yet, the clinical relevance of the dose difference effect of radial ESWT approaches in the management of frozen shoulder patients with type 2 diabetes mellitus remains uncertain.

AIM

The aim was to examine the short-term effects of medium-and high-energy levels of radial ESWT (rESWT) in the treatment of frozen shoulder patients with type 2 diabetes mellitus.

DESIGN

Prospective clinical pilot study.

SETTING

This study was conducted in an outpatient clinic.

POPULATION

Thirty-nine patients who had frozen shoulder untreated for at least 3 months, diagnosed with type 2 diabetes mellitus for ≥3 years were included.

METHODS

The patients were randomly allocated to receive either high-energy rESWT (hrESWT), or medium-energy rESWT (mrESWT) or placebo at 8 Hz twice a week for six weeks. The primary outcome measure was pain, evaluated by the Visual Analog Scale (VAS) Score. Secondary outcome measures were function evaluated by the Shoulder Pain and Disability Index (SPADI) Score, and shoulder active range of motion (AROM). The mechanical properties of the deltoid and trapezius muscles were assessed using the MyotonPRO (Myoton AS, Tallinn, Estonia).

RESULTS

The mrESWT resulted in statistically significant reductions in night pain at 6 weeks (η<inf>p</inf>²=0.27, P=0.003). Significantly improved function (SPADI scores: -35.42±21.29 vs.-29.59±22.60; η<inf>p</inf>²=0.39, P˂0.001) was found in both hrESWT and mrESWT group by 6 weeks. Significantly higher mean shoulder AROM values were recorded for external rotation (η<inf>p</inf>²=0.53, P<0.001), and internal rotation (η<inf>p</inf>²=0.21, P=0.020), in the hrESWT group at the 6^th week. A significantly improved resting tone (η<inf>p</inf>²=0.58) and stiffness of deltoid muscle (η<inf>p</inf>²=0.62) were found in the mrESWT group (P<0.001). The trapezius muscle resting tone reduced with hrESWT (η<inf>p</inf>²=0.17, P=0.033).

CONCLUSIONS

Regardless of the energy levels, rESWT appears to be an effective therapeutic intervention for frozen shoulder patients with type 2 diabetes mellitus in the short-term results.

CLINICAL REHABILITATION IMPACT

Our results suggest that this rESWT can be a useful strategy for the rehabilitation of frozen shoulder patients with type 2 diabetes mellitus. This is the first study on dose difference effectiveness in terms of the clinical significance of rESWT which is key to transfer research evidence into practice.

Assessment of isolated glenohumeral range of motion in patients with adhesive capsulitis can help predict failure of conservative treatment: a pilot study

PURPOSE

To prospectively evaluate a cohort of patients with adhesive capsulitis and identify predictors of failure of conservative treatment in the first 2 months of therapy.

METHODS

This was a single-cohort, prospective observational study that included 20 participants (13 females/7 males; median age of 51.8 years [interquartile range: 8.65]) with primary adhesive capsulitis managed conservatively and evaluated clinically every month for at least 2 years of follow-up (29 [5] months). The evaluation included stage of the disease, treatment applied, radiological findings, pain levels and range of motion (active and passive ROM in the four planes and isolated glenohumeral passive ROM in abduction [GH-ABD], external rotation [GH-ER] and internal rotation). The main outcome assessed was failure of conservative treatment defined as the need for surgery and persistent pain or CMS below 70 points at the 1-year follow-up.

RESULTS

Seven patients (7/20, 35%) were considered to have failed conservative treatment because they required arthroscopic capsular release 5.2 (2.1) months after the initial diagnosis. Of all the clinical and epidemiological variables, absence of improvement during the first 2 months in isolated glenohumeral ROM abduction and external rotation predicted failure of conservative treatment: improvement in GH-ABD (10° or more) occurred in 10/13 patients in the conservative treatment group and in 1/7 patients in the surgery group (p = 0.017). Improvement in GH-ER (10° or more) occurred in 9/13 patients in the conservative treatment group and in 0/7 patients in the surgery group (p = 0.005).

CONCLUSIONS

Precise assessment of isolated glenohumeral ROM in patients with adhesive capsulitis can help identify patients in which conservative treatment might fail. In this study, patients who did not experience early improvements in isolated glenohumeral ROM often required surgery.

LEVEL OF EVIDENCE

III (Prospective cohort study).

Does capsular distension and a short period of countertraction improve outcome following manipulation under anesthesia for the treatment of primary adhesive capsulitis of the glenohumeral joint?

BACKGROUND

Despite the fact that primary adhesive capsulitis of the glenohumeral joint is often considered a self-limiting condition, not all patients make a full recovery. Manipulation under anesthesia (MUA) is performed to forcibly rupture the contracted capsule in a controlled manner. However, the technique, timing, and use of additional injections are often debated. In this study, we report the outcomes following the addition of capsular distension and countertraction to MUA as a treatment for adhesive capsulitis.

METHODS

We performed a retrospective case-cohort study comparing 3 groups: Group 1 underwent MUA alone (n = 54); group 2, MUA with capsular distension (n = 114); and group 3, MUA with capsular distension and countertraction (n = 167). The re-MUA rate, Constant-Murley shoulder (CMS) score, and visual analog scale (VAS) score (for pain) were measured after 6 weeks and 6 months.

RESULTS

The re-MUA rate fell with the addition of both capsular distension and countertraction: 63% in group 1, 39% in group 2, and 18% in group 3. Patients in group 3 recorded the greatest improvement in the CMS score after 6 weeks (+90% vs. +68% in group 2 and +58% in group 1), with all groups showing improvements compared with before treatment. The only independent risk factor identified for re-MUA was smoking. If a second MUA was performed, the CMS (+67%) and VAS (+61%) scores improved, but at 6 months, the CMS score (74.57 ± 7.6 vs. 83.30 ± 5.5) and VAS score (10.57 ± 1.8 vs. 12.96 ± 1.5) remained inferior to those of patients who only needed a single MUA.

DISCUSSION AND CONCLUSION

MUA combined with capsular distension and countertraction reduces the need for a second MUA and results in a faster improvement in functional outcome (CMS score) and reduction of pain (VAS score) compared with MUA alone or MUA with capsular distension. The results of this case-cohort study are of clinical relevance because they show that the efficacy of an MUA can be improved through relatively simple adaptations of the treatment protocol.

A Central Nervous System Focused Treatment Program for People with Frozen Shoulder: A Feasibility Study

Background: Frozen shoulder (FS) is a highly disabling pathology of poorly understood etiology, which is characterized by the presence of intense pain and progressive loss of range of motion (ROM). The aim of this study is to evaluate the feasibility and clinical impact of a CNS-focused treatment program for people with FS. Methods: 10 subjects with primary FS received a 10-week CNS-focused intervention including sensory discrimination training and graded motor imagery techniques delivered as clinic sessions (60 min) and home therapy (30 min five times per week). Measurements were taken at baseline, after a 2-week “washout” period, after treatment, and at three months follow-up. The Shoulder Pain and Disability Index (SPADI) was the primary outcome. Secondary measures were feasibility-related outcomes, self-reported shoulder pain, active and passive range of motion, two-point discrimination threshold (TPDT), left/right judgement task (LRJT), fear-avoidance (Tampa Scale for Kinesiophobia), pain catastrophization (Pain Catastrophizing Scale), and pain sensitization (Central Sensitization Inventory). A Student’s t-test was used to assess the “washout” period. A repeated measure analysis of variance (ANOVA) was used to evaluate within-subjects’ differences for all outcome measures in the different assessment periods and a pairwise analysis was used to compare between the different assessment points. Statistical significance was set at p < 0.05. Results: 70% of participants completed the treatment. No significant changes were found after “washout” period except for TPDT (p = 0.02) and SPADI (p = 0.025). Improvements in self-reported shoulder pain (p = 0.028) and active shoulder flexion (p = 0.016) were shown after treatment (p = 0.028) and follow-up (p = 0.001) and in SPADI at follow-up (p = 0.008). No significant changes were observed in TPDT, LRJT, fear-avoidance, pain catastrophization, and pain sensitization. Conclusions: a CNS-focused treatment program might be a suitable approach to improve pain and disability in FS, but further research is needed to draw firm conclusions.

Evaluating whole-genome expression differences in idiopathic and diabetic adhesive capsulitis

BACKGROUND

Diabetic patients have a greater incidence of adhesive capsulitis (AC) and a more protracted disease course than patients with idiopathic AC. The purpose of this study was to compare gene expression differences between AC with diabetes mellitus and AC without diabetes mellitus.

METHODS

Shoulder capsule samples were prospectively obtained from diabetic or nondiabetic patients who presented with shoulder dysfunction and underwent arthroscopy (N = 16). Shoulder samples of AC with and without diabetes (n = 8) were compared with normal shoulder samples with and without diabetes as the control group (n = 8). Shoulder capsule samples were subjected to whole-transcriptome RNA sequencing, and differential expression was analyzed with EdgeR. Only genes with a false discovery rate < 5% were included for further functional enrichment analysis.

RESULTS

The sample population had a mean age of 47 years (range, 24-62 years), and the mean hemoglobin A_1c level for nondiabetic and diabetic patients was 5.18% and 8.71%, respectively. RNA-sequencing analysis revealed that 66 genes were differentially expressed between diabetic patients and nondiabetic patients with AC whereas only 3 genes were differentially expressed when control patients with and without diabetes were compared. Furthermore, 286 genes were differentially expressed in idiopathic AC patients, and 61 genes were differentially expressed in diabetic AC patients. On gene clustering analysis, idiopathic AC was enriched with multiple structural and muscle-related pathways, such as muscle filament sliding, whereas diabetic AC included a greater number of hormonal and inflammatory signaling pathways, such as cellular response to corticotropin-releasing factor.

CONCLUSIONS

Whole-transcriptome expression profiles demonstrate a fundamentally different underlying pathophysiology when comparing diabetic AC with idiopathic AC, suggesting that these conditions are distinct clinical entities. The new genes expressed explain the differences in the disease course and suggest new therapeutic targets that may lead to different treatment paradigms in these 2 subsets.

The Spatial Extent of Pain Is Associated with Pain Intensity, Catastrophizing and Some Measures of Central Sensitization in People with Frozen Shoulder

The aim of this cross-sectional study was to explore the spatial extent of pain and its association with clinical symptoms, psychological features, and pain sensitization in people with frozen shoulder (FS). Forty-eight individuals with FS completed pain drawings (PDs) and reported their clinical symptoms including pain intensity (Visual Analogue Scale) and shoulder disability (Shoulder Pain and Disability Index). Moreover, pain sensitization measurements (pressure pain thresholds, temporal summation, conditioned pain modulation, and Central Sensitization Inventory (CSI)) were assessed. Psychological features were assessed by Pain Catastrophizing Scale (PCS) and Pain Vigilance and Awareness Questionnaire. Pain frequency maps were generated, Margolis rating scale was used for pain location, and Spearman correlation coefficients were computed. The mean (SD) pain extent was 12.5% (6.7%) and the most common painful area was the anterolateral shoulder region (100%). Women presented a more widespread pain distribution compared with men. Significant positive associations were obtained between pain extent and current pain intensity (rs = 0.421, p < 0.01), PCS (rs = 0.307, p < 0.05) and CSI (rs = 0.358, p < 0.05). The anterolateral region of the shoulder was the most common painful area in people with FS. Women with FS presented more extended areas of pain; and a more widespread distribution of pain was correlated with higher levels of pain, pain catastrophizing and pain sensitization.

Surgical versus Nonsurgical Multimodality Treatment in an Idiopathic Frozen Shoulder: A Retrospective Study of Clinical and Functional Outcomes

This retrospective study compared the clinical and functional outcomes of patients diagnosed with an idiopathic frozen shoulder with symptom onset of a maximum of six months, treated by arthroscopic capsular release followed by corticosteroid injection and physiotherapy to patients who received only corticosteroid injection followed by physiotherapy. The patients who underwent arthroscopic capsular release, intraoperative corticosteroid injection, and physiotherapy (Group I, n = 30) or received only corticosteroids injection and physiotherapy (Group II, n = 29) were examined in terms of shoulder range of motion (ROM), pain intensity, and function before a given treatment and three, six, and twelve months later. The groups were comparable pre-treatment in terms of ROM, pain, and functional outcome. Group I had statistically and clinically significantly better ROM and function at three and six months post-treatment than Group II. Despite being statistically significant, the between-group differences at twelve-month follow-up in ROM and function were too small to be considered clinically notable. The between-group comparison of pain revealed no significant differences at any post-treatment point of time. The early arthroscopic capsular release preceding corticosteroid injection and physiotherapy seemed more effective at three- and six-month follow-up; however, it brought a comparable result to corticosteroid injection and subsequent physiotherapy at twelve months follow-up.

An overview of effective and potential new conservative interventions in patients with frozen shoulder

Frozen shoulder (FS) is a pathology that is difficult to understand and difficult to manage. Over the last ten years, contradictory and new evidence is provided regarding the recovery and its natural course. This narrative review provides new information about the diagnosis and conservative treatment of patients with FS and ongoing research hypotheses that might provide new insights in the pathology and treatment options. FS has a characteristic course. People with Diabetes Mellitus and thyroid disorders have a higher risk of developing a FS. The diagnosis FS is based on pattern recognition and physical examination. Additionally, 'rule-in' and 'rule-out' criteria can be used to increase the likelihood of the frozen shoulder diagnosis. Recommended and most common physical therapy interventions are mobilization techniques and exercises, in which tissue irritability can guide its intensity. In addition, physical therapy is often complementary with patient education and pharmacotherapy. The latest evidence-based practice related to FS is proprioceptive neuromuscular facilitation and mirror therapy. In addition, interventions like pain neuroscience education, high-intensity interval training and lifestyle changes are still hypothetical. Finally, better insight in the involvement of biochemical processes, function of myofibroblasts and matrix metalloproteinases can provide better understanding in the pathophysiology and will be addressed in current review.

MR Imaging Biomarkers for Clinical Impairment and Disease Progression in Patients with Shoulder Adhesive Capsulitis: A Prospective Study

BACKGROUND

MRI diagnostic criteria of shoulder adhesive capsulitis (AC) are nowadays widely used, but there is little information available on the association between MRI findings and clinical impairment.

PURPOSE

To determine the correlation of MRI findings with the Constant-Murley Score (CMS), pain duration and symptoms at the one-year follow-up in AC patients.

MATERIALS AND METHODS

This monocentric prospective study included 132 patients with a clinical diagnosis of shoulder AC who underwent shoulder MRI. Mean patient age was 54.1 ± 9.3 years, and there were 55 men and 77 women. A radiologist examined all patients and completed the CMS just prior to MRI. Pain duration was assessed along with the signal intensity and measured the maximal thickness of the inferior glenohumeral ligament (IGHL) by two radiologists. Medical record analysis was performed in a sub-group of 49 patients to assess prognosis approximately one year after the MRI examination. Linear regression analysis with the Pearson test and the Fisher exact test were used to determine the association between MRI findings and clinical impairment.

RESULTS

There was a significant difference in mean pain duration score (3.8 ± 1.2 versus 3.2 ± 0.9 and 3.8 ± 1.2 versus 3.2 ± 0.9, respectively, for readers 1 and 2) and in mean mobility scores (15.7 ± 8 points versus 19.6 ± 10.1 points and 15.8 ± 8.2 points versus 19.4 ± 10 points, respectively, for readers 1 and 2) in patients with a high IGHL signal compared to those with a low IGHL signal (p < 0.05). IGHL was thicker in patients with clinical improvement at one-year follow-up compared to those presenting clinical stability or worsening (p < 0.05).

CONCLUSIONS

In patients with shoulder AC, the degree of signal intensity at the IGHL was inversely related to shoulder pain duration and range of motion, and a thickened IGHL indicated a favorable outcome at one-year follow-up.

Clinical Guidelines in the Management of Frozen Shoulder: An Update!

Among all the prevalent painful conditions of the shoulder, frozen shoulder remains one of the most debated and ill-understood conditions. It is a condition often associated with diabetes and thyroid dysfunction, and which should always be investigated in patients with a primary stiff shoulder. Though the duration of 'traditional clinicopathological staging' of frozen shoulder is not constant and varies with the intervention(s), the classification certainly helps the clinician in planning the treatment of frozen shoulder at various stages. Most patients respond very well to combination of conservative treatment resulting in gradual resolution of symptoms in 12-18 months. However, the most effective treatment in isolation is uncertain. Currently, resistant cases that do not respond to conservative treatment for 6-9 months could be offered surgical treatment as either arthroscopic capsular release or manipulation under anaesthesia. Though both invasive options are not clinically superior to another, but manipulation could result in unwarranted complications like fractures of humerus or rotator cuff tear.