Biomarkers associated with idiopathic frozen shoulder: a systematic review

Matrix metalloproteinase-1 and matrix metalloproteinase-9 are highly expressed in the joint capsule of diabetic frozen shoulder

BACKGROUND

The pathophysiology of frozen shoulder (FS) involves abnormal expressions of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) that lead to capsular fibrosis. However, there has been little concern for why diabetic FS has more protracted fibrotic condition. The objective of this study was to compare the expression levels of MMPs and TIMPs in the joint capsule of patients with diabetic and nondiabetic FS.

MATERIALS AND METHODS

Samples of capsular tissue were collected from 20 patients with FS (10 diabetic patients; diabetic group and 10 nondiabetic patients; nondiabetic group) and 10 patients (control group) with chronic anterior shoulder instability. Quantitative real-time reverse transcriptase-polymerase chain reaction and Western blot analysis were performed to determine the expression levels of mRNA and protein for MMP-1, 3, 9, 13, 14, and TIMP-1, 2.

RESULTS

The results of quantitative real-time reverse transcriptase-polymerase chain reaction showed significantly higher expression levels of all MMPs and TIMP-1 and significantly lower expression levels of TIMP-2 in the joint capsule of patients in the diabetic or nondiabetic groups compared with the control group. Significantly higher expression levels of MMP-1, 9, 14, and TIMP-1 were detected in the diabetic group compared with the nondiabetic group. The results of Western blot analysis showed significantly higher levels of MMP-3, 13, 14, and TIMP-1 in the joint capsule of patients in the diabetic or nondiabetic groups compared with the control group. However, no significant differences of protein levels of them were observed between diabetic and nondiabetic groups.

CONCLUSIONS

The findings of this study demonstrate the potential involvement of MMP-1 and 9 in the pathophysiology of diabetic FS. These findings may be helpful in identification of therapeutic targets for development of novel treatments for this protracted chronic fibrosing condition.

An injectable thermosensitive hyaluronic acid/pluronic F-127 hydrogel for deep penetration and combination therapy of frozen shoulder

Frozen shoulder (FS) is a common and progressive shoulder disorder that causes glenohumeral joint stiffness, characterized by inflammation and fibrosis. The treatment options are quite limited, and the therapeutic response is hindered by the fibrous membrane formed by excessive collagen and the rapid removal by synovial fluid. To address these challenges, we designed a hyaluronic acid/Pluronic F-127 (HP)-based injectable thermosensitive hydrogel as a drug carrier loaded with dexamethasone and collagenase (HPDC). We screened for an optimal HP hydrogel that can sustain drug release for approximately 10 days both in vitro and in vivo. In the meanwhile, we found that HP hydrogel could inhibit the proliferation and diminish the adhesion capacity of rat synovial cells induced by transforming growth factor-β1. Furthermore, using an established immobilization rat model of FS, intra-articular injection of HPDC significantly improved joint range of motion compared to medication alone. Relying on sustained drug release, the accumulated collagen fibers were degraded by collagenase to promote the deep delivery of dexamethasone. These findings showed a positive combined treatment effect of HPDC, providing a novel idea for the comprehensive treatment of FS.

Sensory innervation of the human shoulder joints in healthy and in chronic pain shoulder syndromes

BACKGROUND

Afferent innervation of shoulder joints plays a fundamental role in nociception and mechanoception and its alteration result in shoulder´s disease that course with pain and functional disability.

METHODS

Joints shoulder from healthy subjects (n = 20) and with chronic pain shoulder syndromes (n = 17) were analyzed using immunohistochemistry for S100 protein to identify nerve structures (nerve fibers and sensory corpuscles), coupled with a quantification of the sensory formations. Sensory nerve formations were quantified in 13 distinct areas in healthy joint shoulder and in the available equivalent areas in the pathological joints. Statistical analyses were conducted to assess differences between healthy shoulder and pathological shoulder joint (p< 0.05).

RESULTS

All analyzed structures, i.e., glenohumeral capsule, acromioclavicular capsule, the extraarticular structures (subcoracoid region and subacromio-subdeltoid bursa) and intraarticular structures (biceps brachii tendon and labrum articulare) are variably innervated except the extrinsic coracoacromial ligament, which was aneural. The afferent innervation of healthy human shoulder joints consists of free nerve endings, simple lamellar corpuscles and Ruffini's corpuscles. Occasionally, Golgi-Mazzoni's and Pacinian corpuscles were found. However, the relative density of each one varied among joints and/or the different zones within the same joint. As a rule, the upper half and anterior half of healthy glenohumeral capsules have a higher innervation compared to the lower and posterior respectably. On the other hand, in joints from subjects suffering chronic shoulder pain, a reduced innervation was found, involving more the corpuscles than free nerve endings.

CONCLUSIONS

Our findings report a global innervation map of the human shoulder joints, especially the glenohumeral one, and this knowledge might be of interest for arthroscopic surgeons allowing to develop more selective and unhurt treatments, controlling the pain, and avoiding the loss of afferent innervation after surgical procedures. To the light of our results the postero-inferior glenohumeral capsular region seems to be the more adequate to be a surgical portal (surgical access area) to prevent nerve lesions.

Prevalence of prediabetes in patients with idiopathic frozen shoulder: a prospective study

Background

The association between diabetes and frozen shoulder is well established. However, the data regarding prediabetes and primary frozen shoulder (PFS) are still lacking.

Methods

In a prospective study, 158 patients with PFS were included. The prediabetes status was ascertained by estimating serum hemoglobin A1c (HbA1c) levels in patients with PFS. According to the level of HbA1c, patients were classified into normoglycemic, prediabetic, and diabetic. In addition, random blood sugar (RBS) was also performed.

Results

Out of 158 participants, 84 (53.2%) were male and 74 (46.8%) were female. Nine patients had bilateral shoulder involvement, and all were diabetics; 47.5% (n = 75) of the patients were in the age group of 51-60 years, 16.5% (n = 26) of the participants were normoglycemic, 37.3% (n = 59) were prediabetics, and 46.2% (n = 73) were diabetics. The difference in mean HbA1c values between the 3 groups was statistically significant (P < .001). However, there was no statistical difference in various age groups (P = .86) or gender (P = .68) between normoglycemics, prediabetics, and diabetics. The difference in mean RBS values between diabetic-nondiabetic and diabetic-prediabetic groups were statistically significant (P < .001), whereas no significant difference was detected between nondiabetic and prediabetic (P = .355).

Conclusion

The prevalence of prediabetes is 37.5% in patients with PFS. Single-point HbA1c estimation is an acceptable tool to detect prediabetes, whereas RBS estimation should not be used to detect prediabetes.

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.

Conditioned Pain Modulation Is Not Impaired in Individuals with Frozen Shoulder: A Case-Control Study

Frozen shoulder (FS) is a poorly understood condition resulting in substantial shoulder pain and mobility deficits. The mechanisms behind FS are not yet fully understood, but, similar to other persistent pain states, central pain mechanisms may contribute to ongoing symptoms in this population. The objective of this research was to investigate conditioned pain modulation (CPM) in people with FS compared with pain-free individuals. A total of 64 individuals with FS and 64 healthy volunteers participated in this cross-sectional study. CPM was assessed by using the pressure pain threshold (PPT) and an occlusion cuff (tourniquet test) as the test and conditioning stimulus, respectively. The absolute and percentage of change in PPT (CPM effect) as well as pain profiles (pro-nociceptive vs. anti-nociceptive) of individuals with FS and healthy controls were calculated. No significant differences in the absolute change in the PPT or CPM effect were found in people with FS compared to pain-free controls. Moreover, no between-group differences in the percentage of subjects with pro-nociceptive and anti-nociceptive pain profiles were observed. These results suggest that endogenous pain inhibition is normally functioning in people with FS. Altered central pain-processing mechanisms may thus not be a characteristic of this population.

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.

Tetrandrine inhibits the occurrence and development of frozen shoulder by inhibiting inflammation, angiogenesis, and fibrosis

BACKGROUND

Frozen shoulders (FS) is a major clinical concern, where chronic synovial inflammation, abnormal angiogenesis, and fibrosis represent the critical pathologies in the glenohumeral capsule. However, no pharmacotherapy has been introduced to treat this pathology. Tetrandrine (TET) has been proposed as a treatment for many diseases due to its strong anti-inflammatory, anti-angiogenic, and anti-fibrotic effects.

PURPOSE

To study the anti-inflammatory, anti-angiogenic, and anti-fibrotic effects of TET on FS, and identify whether TET can prevent the development of FS in rats.

STUDY DESIGN

A controlled laboratory study.

METHODS

Forty-eight male Sprague-Dawley (SD) rats were randomly divided into control, TET, and FS groups. The TET group was intraperitoneally injected with TET every 2 days. TET and saline treatment were started on the day of FS surgery. After 8 weeks, the animals were sacrificed, and samples were collected for X-ray examination, glenohumeral range of motion (ROM) evaluation, histology and immunohistochemistry analysis, transmission electron microscopy (TEM) observation, and profibrogenic factors as well as proinflammatory cytokines measurements.

RESULTS

No significant difference in shoulder ROM was observed between the TET and control groups, but a significant difference was noted between these groups and the FS group (P < 0.01). Immunohistochemical staining showed no abnormal angiogenesis or fibrosis in the TET group or the control group. However, significant angiogenesis, collagen remodeling, and fibrosis were observed in the FS group, and the expression and proportion of type I and type III collagen in the FS group were significantly higher than those in the TET group or the control group (P < 0.01). TEM observation showed that TET protected the ultrastructure of collagen fibrous reticular arrangement of the articular capsule and prevented the formation of scar-like fibrotic structures, which are unique to FS. The significantly increased expression of Smad7 and the suppressed expression of Smad 2 in the TET group compared with that of the FS group indicated that TET also significantly inhibited the TGF-β1 intracellular signal pathway. The expression of profibrogenic factors and proinflammatory cytokines in the TET group and the control group was significantly lower than that in the TET group (P < 0.01).

CONCLUSION

The results demonstrated that TET protected the normal reticular structure of the capsule during the freezing period and prevented the development of FS by inhibiting inflammation, angiogenesis, and fibrosis in a rat FS model.

CLINICAL RELEVANCE

TET may be a safe and effective clinical medication for preventing and treating FS.

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.

The Serum from Patients with Secondary Frozen Shoulder Following Rotator Cuff Repair Induces Shoulder Capsule Fibrosis and Promotes Macrophage Polarization and Fibroblast Activation

PURPOSE

Disorders with systematic inflammation were prognostic for secondary frozen shoulder (sFS) following rotator cuff repair (RCR); however, how systematic inflammation affects sFS remains unclear. The aim of this study was to observe the effect of pre-operative serum from patients with sFS and the serum from those without on shoulder capsule in mice, and on macrophages and fibroblasts in vitro.

METHODS

Serum samples of a consecutive cohort of patients for RCR were collected pre-operatively. Three months after RCR, patients who developed sFS (Group S) were identified. Serum samples from gender- and age-matched controls without sFS (group NS) were also picked out. Firstly, the effect of serum on shoulder capsule fibrosis was observed histologically and biomechanically in a mouse model of RCR. Secondly, the roles of the serum on macrophage polarization and fibroblast activation were investigated, and the potentially involved signaling pathways were identified. Finally, inflammation and fibrosis-related cytokines in serum were quantified.

RESULTS

In our cohort, all patients had free pre-operative shoulder range of motion. Seven patients developed sFS at 3 months after surgery. Seven matched patients without sFS were selected as control. The inter-group difference of basic characteristics was not significant. Compared to the serum of group NS, the serum of group S significantly induced hypercellularity, capsular thickening, and range of motion deficiency in mice shoulders after RCR. Compared to the serum of group NS, samples of group S significantly promoted M2 polarization of THP-1 human macrophages and the activation of human capsule-derived fibroblasts. Meanwhile, Smad3 and p-Smad3 in macrophages and fibroblasts were significantly up-regulated. On the other hand, levels of inflammation and fibrosis-related cytokines were not significantly different between serum in group S and group NS.

CONCLUSION

Although all patients in this cohort had free range of motion pre-operatively, the pre-operative serum from patients with sFS at 3 months after RCR could act as a trigger of shoulder capsule fibrosis post-operatively. This effect may be related to its promotion on macrophage polarization to M2 phenotype and fibroblast activation.

Preoperative Lymphocyte to Monocyte Ratio Can Be a Prognostic Factor in Arthroscopic Repair of Small to Large Rotator Cuff Tears

BACKGROUND

Complete arthroscopic repair can treat small to large rotator cuff tears (RCTs) with good outcomes; however, the repair might be compromised by inflammation.

PURPOSE

To investigate the prognostic value of preoperative lymphocyte to monocyte ratio (LMR), a marker of systemic inflammation before surgery, in arthroscopic rotator cuff repair.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Between January 2014 and January 2016, primary small to large RCTs without stiffness, significant muscle fatty infiltration, or atrophy were completely repaired in 110 consecutive patients and followed. Preoperative LMR was obtained from blood routinely examined 1 day before surgery. Descriptive data and pre- and intraoperative variables were collected. Correlation analysis and multivariable linear regression analysis were used to determine the relationship between preoperative LMR and recovery including American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, Fudan University Shoulder Score (FUSS), visual analog scale (VAS) score for pain, and range of motion (ROM). Poor recovery was defined as ASES score <80, shoulder stiffness as external rotation ≤20°, and pain as VAS score >3. The predictive value of preoperative LMR was determined by receiver operating characteristic (ROC) curve.

RESULTS

A total of 99 patients (101 shoulders) were followed for 2.88 ± 0.43 years. Overall, mean ASES, Constant-Murley, FUSS, and VAS scores were significantly improved at the final follow-up; however, 27 cases had either ASES <80, shoulder stiffness, pain, or a combination of these. Correlation analysis and multivariable linear analysis showed that preoperative LMR was the only factor independently associated with functional recovery, pain, and ROM. Patients with poor recovery had lower preoperative LMR than those with good recovery. Based on the ROC curve, the cutoff value of preoperative LMR was 4.760. Patients with preoperative LMR <4.760 had significantly inferior clinical outcomes compared with their counterparts. The corresponding specificity was 0.542, and sensitivity was 0.779.

CONCLUSION

Arthroscopic repair for small to large RCTs yielded good outcomes; however, some patients still had inferior functional scores, shoulder stiffness, or pain, which correlated with the level of preoperative systemic inflammation. As a marker of systemic inflammation, preoperative LMR could be prognostic for rotator cuff repair.