Hyperthyroidism is a risk factor for developing adhesive capsulitis of the shoulder: a nationwide longitudinal population-based study

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.

Ultrasound-Guided Glenohumeral Corticosteroid Injection for the Treatment of Adhesive Capsulitis of the Shoulder: The Role of Clinical Stage in Response to Treatment

BACKGROUND

Treatment for idiopathic adhesive capsulitis of the shoulder remains controversial. Stages 1 to 2 reflect an inflammatory process supporting a rationale for intra-articular glenohumeral joint corticosteroid injection to treat synovial inflammation and prevent progression to capsular fibrosis.

HYPOTHESIS

We hypothesize that an intra-articular ultrasound-guided glenohumeral injection (USGI) of corticosteroid in patients diagnosed with Stage 1 or 2 idiopathic adhesive capsulitis will result in timely functional recovery and resolution of pain and stiffness.

STUDY DESIGN

Case series.

LEVEL OF EVIDENCE

Level 4.

METHODS

Patients with Stage 1 or 2 idiopathic adhesive capsulitis treated with an intra-articular corticosteroid injection were included. Patients were seen by a single physician and diagnosed using history and physical examination with careful attention to measurement of glenohumeral range of motion (ROM). A total of 61 patients met inclusion criteria. ROM measurements documented in the patient charts were recorded in forward flexion, abduction, internal rotation, and external rotation in neutral abduction. All ROM measurements were performed pre- and postinjection. All patients were treated with an USGI of local anesthetic and depomedrol. Recovery criteria were defined as forward flexion, abduction, and external rotation within 15° of the contralateral side and internal rotation within 3 spinous process levels of the contralateral side.

RESULTS

A total of 11 patients with Stage 1 and 50 patients with Stage 2 adhesive capsulitis comprised the final study cohort. Within the Stage 1 cohort, all 11 patients met recovery criteria for forward flexion and internal rotation (100%), 10 met recovery criteria for abduction (91%), and 8 met recovery criteria for external rotation (73%). Within the Stage 2 cohort, 31 patients met recovery criteria for forward flexion (62%), 30 met recovery criteria for abduction (60%), 36 met recovery criteria for internal rotation (72%), and 25 met recovery criteria for external rotation (50%). The difference in time to recovery in days was statistically significant in all ROM planes and was within 2 to 6 weeks for patients in Stage 1 and 7 to 10 weeks for Stage 2.

CONCLUSION

USGI for early adhesive capsulitis allows patients to recover ROM more rapidly if performed early after onset of pain and stiffness.

CLINICAL RELEVANCE

These results stress the importance of recognition of idiopathic adhesive capsulitis in its early stages and subsequent intervention with an intra-articular glenohumeral corticosteroid injection.

Decreased rotator cuff muscle cross-sectional areas in subjects with adhesive capsulitis: a study comparing male and female subjects

OBJECTIVE

To compare rotator cuff (RC) muscle cross-sectional areas (CSA) in subjects with adhesive capsulitis (AC) to age- and sex-matched controls.

MATERIALS AND METHODS

We retrospectively analyzed 97 shoulder MRIs or MR arthrography studies, of which 42 were clinically diagnosed with AC (27 female, 15 male) and 55 were age- and sex-matched controls (38 female, 17 male). All AC subjects underwent imaging ≥ 6 months after symptom onset. All imaging was examined to exclude RC full-thickness tears and prior surgery. A standardized T1 sagittal MR image was segmented in each subject to obtain the CSA of subscapularis (SSC), supraspinatus (SSP), and infraspinatus (ISP) muscles. Differences in CSAs between AC and control subjects were analyzed by sex (females and males separately) and all subjects combined.

RESULTS

AC females had significantly decreased SSC (P = 0.002) and total (P = 0.006) CSAs compared to controls. Male AC subjects showed decreased SSC (P = 0.044), SSP (P = 0.001), and total (P = 0.005) CSAs. Across all subjects, male and female, the AC cohort had significantly decreased SSC (P = 0.019) and total (P = 0.029) CSAs compared to controls.

CONCLUSION

Decreased RC muscle CSAs were present in AC subjects with ≥ 6 months of symptom duration, with decreased SSC and total CSAs in male and female subjects, and decreased SSP CSA in males.

An Updated Overview of Risk Factors for Shoulder Stiffness

A painful reduction in shoulder mobility, known as "shoulder stiffness", can occur both as a primary idiopathic condition and as a secondary condition, for example, following surgical procedures. Various factors can contribute to the development of primary shoulder stiffness. In this review we summarize the pathophysiological mechanisms, genetic influences, endocrine disorders, metabolic conditions, as well as other diseases and medical-therapeutic approaches that might have an impact on the development of primary shoulder stiffness.

Predictive Factors of Intra-articular Corticosteroid Injections With Ultrasound-Guided Posterior Capsule Approach for Patients With Primary Adhesive Capsulitis

BACKGROUND

Adhesive capsulitis affects the shoulder joint, causing pain and limiting motion. In clinical practice, the effectiveness of injections varies, and the factors influencing their success remain unclear. This study investigates the predictors of effective corticosteroid injections in patients with primary adhesive capsulitis.

DESIGN

This retrospective study enrolled adhesive capsulitis patients older than 35 yrs who received intra-articular corticosteroid injections. The response was determined based on patients' pain and range of motion 3 mos after the injection. Demographic data, medical comorbidities, and radiographic parameters (critical shoulder angle and acromial index) were compared between the effective and noneffective groups. Receiver operating characteristic curves and logistic regression were used to identify the predictors of injection effectiveness.

RESULTS

This study included 325 patients with primary adhesive capsulitis, who were divided into responder (189 patients, 58.2%) and nonresponder (136 patients, 41.8%) groups. The receiver operating characteristic curve revealed that the acromial index score indicated favorable discrimination for predicting a poor response to injections, whereas the critical shoulder angle score did not. Logistic regression revealed that the pain period, diabetes mellitus, and acromial index are predictors of nonresponders to injections.

CONCLUSIONS

Long pain duration, the presence of diabetes mellitus, and an acromial index score greater than 0.711 were predictors of nonresponse to corticosteroid injections for primary adhesive capsulitis patients.

The Risk of Shoulder Adhesive Capsulitis in Individuals with Prediabetes and Type 2 Diabetes Mellitus: A Longitudinal Nationwide Population-Based Study

BACKGRUOUND

This study aimed to investigate the association between type 2 diabetes mellitus (T2DM) and shoulder adhesive capsulitis (AC) using a large-scale, nationwide, population-based cohort in the Republic of Korea.

METHODS

A total of 3,471,745 subjects aged over 20 years who underwent a National Health Insurance Service medical checkup between 2009 and 2010 were included in this study, and followed from the date of their medical checkup to the end of 2018. Subjects were classified into the following four groups based on the presence of dysglycemia and history of diabetes medication: normal, prediabetes, newly diagnosed T2DM (new-T2DM), and T2DM (claim history for antidiabetic medication). The endpoint was new-onset AC during follow-up. The incidence rates (IRs) in 1,000 person-years and hazard ratios (HRs) of AC for each group were analyzed using Cox proportional hazard regression models.

RESULTS

The IRs of AC were 9.453 (normal), 11.912 (prediabetes), 14.933 (new-T2DM), and 24.3761 (T2DM). The adjusted HRs of AC in the prediabetes, new-T2DM, and T2DM groups were 1.084 (95% confidence interval [CI], 1.075 to 1.094), 1.312 (95% CI, 1.287 to 1.337), and 1.473 (95% CI, 1.452 to 1.494) compared to the normal group, respectively. This secular trend of the HRs of AC according to T2DM status was statistically significant (P<0.0001).

CONCLUSION

This large-scale, longitudinal, nationwide, population-based cohort study of 3,471,745 subjects confirmed that the risk of AC increases in prediabetic subjects and is associated with T2DM status.

Allogenic Platelet-Rich Plasma for the Treatment of Adhesive Capsulitis

Adhesive capsulitis (AC) is a common shoulder disorder leading to pain and restricted range of motion (ROM) and affects the patient's activities of daily living (ADL) and overall quality of life (QoL). Conservative therapies are prioritized, resorting to surgical intervention only when necessary. Unfortunately, these modalities have limitations and do not address the underlying pathological cause of AC. The use of autologous biologics, such as platelet-rich plasma (PRP), has evolved and shown promise for managing musculoskeletal (MSK) injuries, including AC. However, subpar functional outcomes have led clinicians to question the long-term efficacy of autologous PRP. To circumvent this, the possibility of utilizing a standardized and well-characterized allogenic PRP for AC has been explored. In this manuscript, we qualitatively present in vitro, pre-clinical, clinical, and ongoing studies investigating the varied applications of allogenic PRP for the management of AC. The results demonstrated that allogenic PRP acts in a pleiotropic manner and decreases pro-inflammatory cytokines only in the inflammatory condition. In addition, the administration of allogenic PRP is safe and potentially efficacious, in terms of reducing pain and improving range of motion, shoulder strength, and function, in non-surgical management of AC. Nonetheless, more pre-clinical studies and adequately powered, multicenter, prospective, non-randomized, and randomized controlled trials with longer follow-up are warranted to further establish the safety and efficacy of allogenic PRP and justify its routine clinical use.

Adhesive Capsulitis

Adhesive capsulitis, colloquially known as "frozen shoulder," is a relatively common disorder, affecting approximately 2% to 5% of the general population. The incidence may be higher as the condition can be relatively mild and self-limited and thus many patients who experience it may never present for treatment. It involves a pathologic process of gradual fibrosis of the glenohumeral joint that leads to limited active and passive range of motion, contracture of the joint capsule, and shoulder pain.

Prevalence of and Risk Factors for Adhesive Capsulitis of the Shoulder in Older Adults from Germany

This study aimed to investigate the prevalence of and risk factors for adhesive capsulitis in older adults from Germany. The one-year and lifetime prevalence of adhesive capsulitis were assessed in adults aged ≥65 years with at least one visit to one of 1207 general practices in Germany in 2021. Associations between physical and psychiatric conditions and adhesive capsulitis were further assessed in older patients diagnosed for the first time with adhesive capsulitis in general practices in 2010-2021 (index date) and matched (1:5) to patients without adhesive capsulitis using a propensity score based on age, sex, and the index year. In adults without adhesive capsulitis, the index date was a randomly selected visit date in 2010-2021. The one-year and lifetime prevalence of adhesive capsulitis in older adults in 2021 were 0.4% and 2.4%, respectively. In 8439 patients with and 42,195 patients without adhesive capsulitis, 12 conditions were positively and significantly associated with adhesive capsulitis. Effect sizes were strongest for other and unspecified osteoarthritis (OR = 1.93), injury to the shoulder and upper arm (OR = 1.85), and injury to the thorax (OR = 1.47). Based on these findings, adhesive capsulitis can occur at older age, and osteoarthritis and injuries are major risk factors.

Trends in Practice Among Shoulder Specialists in the Management of Frozen Shoulder: A Consensus Survey

Background:

The management of frozen shoulder (FS) differs depending on experience level and variation between scientific guidelines and actual practice.

Purpose:

To determine the current trends and practices in the management of FS among shoulder specialists and compare them with senior shoulder specialists.

Study Design:

Consensus statement.

Methods:

A team of 15 senior shoulder specialists (faculty group) prepared a questionnaire comprising 26 questions regarding the definition, terminology, clinical signs, investigations, management, and prognosis of FS. The questionnaire was mailed to all the registered shoulder specialists of Shoulder and Elbow Society, India (SESI) (specialist group; n = 230), as well as to the faculty group (n = 15). The responses of the 2 groups were compared, and levels of consensus were determined: strong (>75%), broad (60%-74.9%), inconclusive (40%-59.9%), or disagreement (<40%).

Result:

Overall, 142 of the 230 participants in the specialist group and all 15 participants in the faculty group responded to the survey. Both groups strongly agreed that plain radiographs are required to rule out a secondary cause of FS, routine magnetic resonance imaging is not indicated to confirm FS, nonsteroidal anti-inflammatory drugs should be administered at bedtime, steroid injection (triamcinolone or methylprednisolone) is the next best option if analgesics fail to provide pain relief, passive physical therapy should be avoided in the freezing phase, <10% of patients would require any surgical intervention, and patients with diabetes and thyroid dysfunction tend to fare poorly. There was broad agreement that routine thyroid dysfunction screening is unnecessary for women, a single 40-mg steroid injection via intra-articular route is preferred, and arthroscopic capsular release (ACR) results in a better outcome than manipulation under anesthesia (MUA). Agreement was inconclusive regarding the use of combined random blood sugar (RBS) and glycosylated hemoglobin versus lone RBS to screen for diabetes in patients with FS, preference of ACR versus MUA to treat resistant FS, and the timing of surgical intervention. There was disagreement over the most appropriate term for FS, the preferred physical therapy modality for pain relief, the most important movement restriction for early diagnosis of FS, and complications seen after MUA.

Conclusion:

This survey summarized the trend in prevalent practices regarding FS among the shoulder specialists and senior shoulder surgeons of SESI.

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 epidemiology and etiology of adhesive capsulitis in the U.S. Medicare population

Background

Adhesive capsulitis (AC) of the shoulder, also known as frozen shoulder, causes substantial pain and disability. In cases of secondary AC, the inflammation and fibrosis of the synovial joint can be triggered by trauma or surgery to the joint followed by extended immobility. However, for primary AC the inciting trigger is unknown. The burden of the disorder among the elderly is also unknown leading to this age group being left out of therapeutic research studies, potentially receiving delayed diagnoses, and unknown financial costs to the Medicare system. The purpose of this analysis was to describe the epidemiology of AC in individuals over the age of 65, an age group little studied for this disorder. The second purpose was to investigate whether specific medications, co-morbidities, infections, and traumas are risk factors or triggers for primary AC in this population.

Methods

We used Medicare claims data from 2010–2012 to investigate the prevalence of AC and assess comorbid risk factors and seasonality. Selected medications, distal trauma, and classes of infections as potential inflammatory triggers for primary AC were investigated using a case–control study design with patients with rotator cuff tears as the comparison group. Medications were identified from National Drug codes and translated to World Health Organization ATC codes for analysis. Health conditions were identified using ICD9-CM codes.

Results

We found a one-year prevalence rate of AC of approximately 0.35% among adults aged 65 years and older which translates to approximately 142,000 older adults in the United States having frozen shoulder syndrome. Diabetes and Parkinson’s disease were significantly associated with the diagnosis of AC in the elderly. Cases were somewhat more common from August through December, although a clear seasonal trend was not observed. Medications, traumas, and infections were similar for cases and controls.

Conclusions

This investigation identified the burden of AC in the US elderly population and applied case–control methodology to identify triggers for its onset in this population. Efforts to reduce chronic health conditions such as diabetes may reduce seemingly unrelated conditions such as AC. The inciting trigger for this idiopathic condition remains elusive.

Effects of comorbidities on the outcomes of manipulation under anesthesia for primary stiff shoulder

BACKGROUND

Studies on the effects of manipulation under anesthesia (MUA) for primary stiff shoulder when different comorbidities are present are lacking. Our aim was to assess how comorbidities influence the recovery speed and clinical outcomes after MUA.

METHODS

Between April 2013 and September 2018, 281 consecutive primary stiff shoulders in the frozen phase treated with MUA were included in this study. We investigated the comorbidities of patients and divided them into the control (n = 203), diabetes mellitus (DM) (n = 32), hyperlipidemia (n = 26), and thyroid disorder (n = 20) groups. The range of motion (ROM) and clinical scores for each group before MUA and 1 week, 6 weeks, and 3 months after MUA were comparatively analyzed. We identified the ROM recovery time after MUA and the responsiveness to MUA. Then, subjects were subdivided into early and late recovery groups based on their recovery time and into successful and nonsuccessful MUA groups based on their responsiveness to MUA.

RESULTS

Significant improvements in ROM and clinical scores at 3 months after MUA were observed in all groups. Significant differences in ROM among the 4 groups were also observed during follow-up (P < .05). The DM group had significantly lower ROM values, even at 3 months after MUA, compared with the control group. The ROM recovery speed after MUA was slowest in the DM group, followed by the thyroid disorder, hyperlipidemia, and control groups. Most (90.6%) of the DM group experienced late recovery. The proportion of nonsuccessful MUA was higher in the DM and thyroid disorder groups than that in the control and hyperlipidemia groups (P = .004). During follow-up, there were no differences among groups regarding the visual analog scale, University of California at Los Angeles shoulder, and Constant scores.

CONCLUSION

The ROM recovery speed and responsiveness to MUA for primary stiff shoulder were poorer for the DM and thyroid disorder groups than for the control group. In particular, compared with any other disease, outcomes were poorer when the comorbidity was DM. If patients have comorbidities, then they should be informed before MUA that the comorbidity could affect the outcomes of treatment.

Allogenic Pure Platelet-Rich Plasma Therapy for Adhesive Capsulitis: A Bed-to-Bench Study With Propensity Score Matching Using a Corticosteroid Control Group

BACKGROUND

While platelet-rich plasma (PRP) has been widely studied for musculoskeletal disorders, few studies to date have reported its use for adhesive capsulitis (AC). Fully characterized and standardized allogenic PRP may provide clues to solve the underlying mechanism of PRP with respect to synovial inflammation and thus may clarify its clinical indications.

PURPOSE

To clinically evaluate the safety and efficacy of a fully characterized pure PRP injection in patients with AC and to assess the effects of pure PRP on synoviocytes with or without inflammation in vitro.

STUDY DESIGN

Controlled laboratory study and cohort study; Level of evidence, 3.

METHODS

For the clinical analysis, a total of 15 patients with AC received an ultrasonography-guided intra-articular PRP injection and were observed for 6 months. Pain, range of motion (ROM), muscle strength, shoulder function, and overall satisfaction in the patients were evaluated using questionnaires at 1 week as well as at 1, 3, and 6 months after the PRP injection and results were compared with the results of a propensity score-matched control group that received a corticosteroid injection (40 mg triamcinolone acetonide). For the in vitro analysis, synoviocytes were cultured with or without interleukin-1β (IL-1β) and PRP. The gene expression of proinflammatory and anti-inflammatory cytokines as well as matrix enzymes and their inhibitors was evaluated.

RESULTS

At 6-month follow-up, pure PRP significantly decreased pain and improved ROM, muscle strength, and shoulder function to levels comparable with those after a corticosteroid injection. All pain values, strength measurements, and functional scores significantly improved up to 6 months in the PRP group, but these measures improved up to 3 months and then were decreased at 6 months in the corticosteroid group. ROM was significantly improved in the 2 groups at 6 months compared with baseline. Allogenic PRP did not cause adverse events. For the in vitro findings, PRP induced inflammation but significantly improved the IL 1β-induced synovial inflammatory condition by decreasing proinflammatory cytokines such as IL-1β, tumor necrosis factor-α, IL-6, cyclooxygenase-2, and microsomal prostaglandin E synthase-1 and decreased matrix enzymes (matrix metalloproteinase-1, -3, and -13 as well as a disintegrin and metalloproteinase with thrombospondin motifs-4 and -5) and further increasing anti-inflammatory cytokines such as vasoactive intestinal peptide.

CONCLUSION

This study showed that PRP decreased pain and improved shoulder ROM and function to an extent comparable with that of a corticosteroid in patients with AC. Allogenic pure PRP acted in a pleiotropic manner and decreased proinflammatory cytokines only in the inflammatory condition.

CLINICAL RELEVANCE

Allogenic PRP could be a treatment option for the inflammatory stage of AC.

Hyperlipidemia Is a Risk Factor of Adhesive Capsulitis: Real-World Evidence Using the Taiwanese National Health Insurance Research Database

Background:

Patients with adhesive capsulitis are evaluated for pain and progressive contracture of the glenohumeral joint. Whether endocrine, immune, or inflammatory processes are involved in its definite pathogenesis is still under debate. Some cross-sectional studies with a small sample size have noted that hyperlipidemia is a possible risk factor for frozen shoulders.

Purpose/Hypothesis:

The purpose was to conduct a longitudinal population-based study to investigate the risk of adhesive capsulitis among patients with hyperlipidemia. It was hypothesized that patients with hyperlipidemia would have a higher risk of adhesive capsulitis and that the use of statin drugs could reduce the rate.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Using data from the National Health Insurance Research Database (NHIRD) of Taiwan, the authors obtained the records of patients with hyperlipidemia who received a diagnosis between 2004 and 2005 and were followed up until the end of 2010. The control cohort comprised age- and sex-matched patients without hyperlipidemia. Propensity score matching was performed for the other comorbidities. A Cox multivariate proportional hazards model was applied to analyze the risk factors of adhesive capsulitis. The hazard ratio (HR) and adjusted HR were estimated between the study and control cohorts after adjustment for confounders. The effects of statin use on adhesive capsulitis risk were also analyzed.

Results:

The NHIRD records of 28,748 patients and 114,992 propensity score–matched controls were evaluated. A higher incidence rate of adhesive capsulitis was revealed in the hyperlipidemia cohort, with a crude HR of 1.70 (95% CI, 1.61-1.79; P < .001) and adjusted HR of 1.50 (95% CI, 1.41-1.59; P < .001). Patients with hyperlipidemia who used a statin still had higher crude and adjusted HRs compared with controls. Statin use did not exert protective effects on patients with hyperlipidemia.

Conclusion:

Patients with hyperlipidemia had a 1.5-fold higher risk of adhesive capsulitis than did healthy controls. Statin use did not provide protection against adhesive capsulitis in patients with hyperlipidemia.

Therapeutic efficacy of low-dose steroid combined with hyaluronidase in ultrasonography-guided intra-articular injections into the shoulder for adhesive capsulitis

PURPOSE

The purpose of this study was to compare the efficacy of low-dose steroid, high-dose steroid, and low-dose steroid combined with hyaluronidase with respect to intra-articular injection therapy for adhesive capsulitis (AC) of the shoulder.

METHODS

Thirty patients with primary AC in the initial stage were randomly assigned into three groups to receive ultrasound-guided intra-articular injections with 20 mg of triamcinolone acetonide (group A, n=10), 40 mg of triamcinolone acetonide (group B, n=10) and 20 mg of triamcinolone acetonide combined with hyaluronidase (group C, n=10). The outcome measures included a visual analogue scale (VAS), the Shoulder Disability Questionnaire (SDQ), abduction and external rotation range of motion, and intra-sheath fluid (ISF) before treatment and at 2, 4, 8, and 16 weeks after treatment.

RESULTS

Among the 30 patients, one participant in group B dropped out; therefore, a total of 29 patients completed this study and were successfully injected. After the injection, the VAS, SDQ, range of flexion and external rotation, and ISF improved in all groups compared with the preinjection status, regardless of treatment or time point. In the comparison between groups, the SDQ and ISF showed significantly greater improvements in groups B and C than in group A.

CONCLUSION

The therapeutic efficacy of combined low-dose corticosteroid and hyaluronidase is superior to that of low-dose corticosteroid and equivalent to that of high-dose corticosteroid in early AC.

The presence of gastroesophageal reflux disease increases the risk of developing postoperative shoulder stiffness after arthroscopic rotator cuff repair

BACKGROUND

Postoperative shoulder stiffness (SS) after arthroscopic rotator cuff (RC) repair has been reported with a variable incidence, and numerous preoperative risk factors have been described. This prospective study aimed to document the incidence of postoperative SS and to evaluate the role of preoperative risk factors in the development of this complication, with a special focus on the role of gastroesophageal reflux disease (GERD).

METHODS

Preoperative risk factors for SS were prospectively evaluated in 237 consecutive patients undergoing arthroscopic single-row RC repair. The presence of GERD was evaluated with the GerdQ diagnostic tool. Postoperative SS was diagnosed according to the criteria described by Brislin et al in 2007.

RESULTS

The incidence of postoperative SS was 8.02%. The presence of GERD was significantly associated with the development of postoperative SS (odds ratio [OR], 5.265; 95% confidence interval [CI], 1.657-1.731; P = .005). Older age (OR, 0.896; 95% CI, 0.847-0.949; P < .001), male sex (OR, 0.126; 95% CI, 0.0252-0.632; P = .012), and number of pregnancies (OR, 0.47; 95% CI, 0.228-0.967; P = .040) emerged as protective factors.

CONCLUSIONS

The presence of GERD significantly influences the development of postoperative SS after arthroscopic single-row RC repair. An underlying aspecific proinflammatory condition, characterized by increased expression of tumor necrosis factor α and transforming growth factor β, and disorders in retinoid metabolism are hypotheses that could explain this previously unknown association. The documented incidence of postoperative SS falls within previously reported ranges, with women being significantly more affected than men.

The puzzling pathophysiology of frozen shoulders - a scoping review

Purpose

The pathophysiology of frozen shoulders is a complex and multifactorial process. The purpose of this review is to scope the currently available knowledge of the pathophysiology of frozen shoulders.

Methods

A systematic search was conducted in Medline, Embase and the Cochrane library. Original articles published between 1994 and October 2020 with a substantial focus on the pathophysiology of frozen shoulders were included.

Results

Out of 827 records, 48 original articles were included for the qualitative synthesis of this review. Glenohumeral capsular biopsies were reported in 30 studies. Fifteen studies investigated were classified as association studies. Three studies investigated the pathophysiology in an animal studies. A state of low grade inflammation, as is associated with diabetes, cardiovascular disease and thyroid disorders, predisposes for the development of frozen shoulder. An early immune response with elevated levels of alarmins and binding to the receptor of advance glycation end products is present at the start of the cascade. Inflammatory cytokines, of which transforming growth factor-β1 has a prominent role, together with mechanical stress stimulates Fibroblast proliferation and differentiation into myofibroblasts. This leads to an imbalance of extracellular matrix turnover resulting in a stiff and thickened glenohumeral capsule with abundance of type III collagen.

Conclusion

This scoping review outlines the complexity of the pathophysiology of frozen shoulder. A comprehensive overview with background information on pathophysiologic mechanisms is given. Leads are provided to progress with research for clinically important prognostic markers and in search for future interventions.

Level of evidence

Level V.

A Comprehensive Update of Adhesive Capsulitis and Minimally Invasive Treatment Options

Background

Adhesive capsulitis of the shoulder (AC) is characterized by fibrosis and contracture of the glenohumeral joint capsule, resulting in progressive stiffness, pain, and restriction of motion of the shoulder. The prevalence of AC is estimated to be 2-5% of the general population. Patients with AC typically have an insidious onset of pain and can progress to severe limitation of the shoulder leading to significant disability and decreased quality of life.

Objectives

The objective of this manuscript is to provide a comprehensive review of AC with a focus on clinical presentation, natural history, pathophysiology, and various treatment modalities.

Study Design

A review article.

Setting

A review of literature.

Methods

A search was made on the Pubmed database using the keywords of adhesive capsulitis, frozen shoulder, shoulder capsulitis, arthrofibrosis, shoulder pain, shoulder stiffness.

Results

Our search identified numerous studies in order to provide a comprehensive review of the current understanding of the treatment and management of AC.

Limitations

There remains limited evidence in literature about the understanding of AC and optimal treatment.

Conclusion

AC is an important cause of chronic pain and disability. There is currently no consensus on treatment. Initial treatment modalities revolve around conservative measures as well as aggressive physical therapy. Further treatment options include intraarticular injections, hydro-dilation, nerve blocks, and for more refractory cases, surgical interventions such as arthroscopic capsulotomy.

Motor Imagery Performance and Tactile Spatial Acuity: Are They Altered in People with Frozen Shoulder?

Frozen shoulder (adhesive capsulitis) is a severe chronic pain condition that is not well understood and current treatment is suboptimal. In several other chronic pain conditions motor imagery and tactile acuity deficits are present, which are thought to represent associated neuroplastic changes. The aims of this study were to determine if motor imagery performance assessed by the left/right judgement task, and tactile acuity assessed by two-point discrimination, are altered in people with unilateral frozen shoulder. In this cross-sectional, prospective study eighteen adults diagnosed with frozen shoulder in a physiotherapy clinic setting completed a left/right judgement task, response times (RT) and accuracy for the left/right judgement task were determined. Next, tactile acuity over both shoulders was assessed with a novel, force-standardised two-point discrimination test. Results corresponding to the affected side were compared to the pain free shoulder; Left/right judgement task: mean RT (SD) corresponding to the affected shoulder was significantly slower than RT for the healthy shoulder (p = 0.031). There was no side-to-side difference in accuracy (p > 0.05). Neither RT nor accuracy was related to pain/disability scores or duration of symptoms (p > 0.05). Two-point discrimination: mean two-point discrimination threshold of the affected shoulder was significantly larger than the contralateral healthy shoulder (p < 0.001). Two-point discrimination threshold was not related to pain/disability scores or pain duration (p > 0.05); One explanation for these findings is altered sensorimotor processing and/or disrupted sensorimotor cortex representations of the affected shoulder. A case then exists for the use of treatments aimed at reversing these changes, training the brain to reduce chronic shoulder pain.

Transcriptomic analysis of adhesive capsulitis of the shoulder

Adhesive capsulitis (AC) is a disabling condition of the shoulder joint affecting 2 to 5% of the general population. Our understanding of the molecular mechanisms is limited. The present study aimed to determine potential biomarkers of AC through transcriptomic analysis. This multi-centre study investigated patients undergoing arthroscopic capsulotomy surgery for resistant AC compared to those undergoing arthroscopic stabilization surgery for glenohumeral instability (control). Tissue samples were harvested from the anterior capsule during surgery. Total RNA was extracted and RNA-sequencing-based transcriptomics were performed. A number of genes deemed differentially expressed in RNA-sequencing analysis were validated using real-time reverse transcription polymerase chain reaction (RT-PCR). Baseline characteristics of the AC group (n = 22) were; mean age 52.7 years (SD: 10.2), 73% female, and Oxford Shoulder Score 19.6 (SD: 8.0), compared with the control group (n = 26), average age 23.9 years (SD: 5.2), 15% female, and Oxford Shoulder Score 39.0 (SD: 7.4). Transcriptomic analysis with false discovery rate correction and log₂ fold change cut-off of ±1.5 revealed 545 differentially expressed genes in AC relative to control. Bioinformatic analyses were carried out to identify biological processes and pathways enriched in this dataset. Real-time RT-PCR using two different normalization processes confirmed increased expression of matrix metallopeptidase 13 (MMP13) and platelet-derived growth factor subunit B (PDGFB), in patients with AC, while tumor necrosis factor α (TNFA) expression was reduced. These findings provide a comprehensive assessment of transcriptional changes associated with AC that give insights into the aetiology of the disease and provides a resource for molecular targets to better diagnose and treat this condition.

Type 1 Complex Regional Pain Syndrome After Subacromial Shoulder Surgery: Incidence and Risk Factor Analysis

INTRODUCTION

Complex Regional Pain Syndrome type 1 (CRPS1) is a potential complication, affecting the prognosis of functional joint recovery. Its incidence ranges from 2 to 40% depending on the series and the joints involved. Very few studies have evaluated the incidence of CRPS after shoulder surgery. The objective of our study was to determine the incidence of CRPS1 and to identify any pre-operative risk factors associated with its emergence after extra-articular subacromial space surgery.

MATERIAL AND METHODS

This is a retrospective single-centre study of patients who underwent surgery for a subacromial extra-articular shoulder pathology from January 2016 to December 2016 and included a follow-up period of at least 6 months. The primary inclusion criterion was developing a CRPS1 as defined by Veldman. A pre- and post-operative clinical assessment was performed based on the Constant (Cst) score.

RESULTS

Among the 287 patients, with an average follow-up period of 6.5 months, included in the study, 38 (13%) presented with post-operative CRPS1. Treated hypothyroidism (OR = 3.79; 95% CI 1.58;9.07; p = 0.003), open surgery (OR = 2.92; 95% CI 1.35-6.32; p = 0.007) and the level of daily physical activity from the Cst score (OR = 0.088; 95% CI 0.79;0.97; p = 0.015) were found to be significantly associated with the onset of CRPS1.

CONCLUSION

CRPS1 affected more than 10% of patients who underwent surgery for a subacromial shoulder pathology. The current study identified hypothyroidism, open surgery, and pre-operative clinical status as risk factors for the onset of this complication. These parameters should, therefore, be taken into consideration during the patient's pre-operative consultation.

Association between Frozen Shoulder and Thyroid Diseases: Strengthening the Evidences

Objective  To clarify the association of thyroid disorders and primary frozen shoulder by comparing this group with controls without shoulder disease and with patients with rotator cuff tears.

Methods  We evaluated 166 patients who presented frozen shoulder with treatment in progress or already treated, which were compared with 129 patients with diagnosis of rotator cuff tears and 251 control subjects. All of the participants answered the questionnaire on the following variables: age, gender, body mass index (BMI), occupation, physical activity, presence of thyroid disorders and other comorbidities, smoking and use of alcohol.

Results  When comparing the frozen shoulder group with the control and rotator cuff groups, there is a specific association between the presence of thyroid disorders and frozen shoulder. By calculating relative risk, it is possible to state that an individual with thyropathy has 2.69 more chance of developing frozen shoulder. Also, there was an association with gender, since women with frozen shoulder exceeded significantly the risk.

Conclusions  Thyroid disorders, especially hypothyroidism and the presence of benign thyroid nodules, are risk factors significantly associated with frozen shoulder, rising the chances to 2.69 times of developing frozen shoulder.

This is the first study that uses, in addition to the control group, a second group with rotator cuff tears, so it was shown that there is a specific association of thyroid disorders and frozen shoulder, but not with shoulder disorders in general.

Patients with Axial Spondyloarthritis Are at Risk of Developing Adhesive Capsulitis: Real-World Evidence Database Study in Taiwan

Patients with axial spondyloarthritis (ax-SpA) present with inflammation invading the axial skeleton. Symptoms of ax-SpA interfere with patients' quality of life, and peripheral symptoms are also noted. Human leukocyte antigen B27 was associated with adhesive capsulitis. However, epidemiological studies investigating the associated incidence and risk factors for patients with ax-SpA with adhesive capsulitis are limited. The data of patients with ax-SpA were recorded during the 2004-2008 period and followed to the end of 2010. The control cohort comprised age- and sex-matched non-ax-SpA subjects. A Cox multivariate proportional hazards model was applied to analyze the risk factors for adhesive capsulitis. The hazard ratio (HR) and adjusted hazard ratio (aHR) were estimated between the study and control cohorts after confounders were adjusted for. Effects of sulfasalazine (SSZ), methotrexate (MTX), and hydroxychloroquine (HCQ) use on adhesive capsulitis risk were also analyzed. We enrolled 2859 patients with ax-SpA in the study cohort and 11,436 control subjects. A higher incidence of adhesive capsulitis was revealed in the ax-SpA cohort: The crude HR was 1.63 (95% CI, 1.24-2.13; p < 0.001), and the aHR was 1.54 (95% CI, 1.16-2.05; p = 0.002). For patients with ax-SpA using SSZ or HCQ, no difference in aHR was noted compared with control participants, but patients with ax-SpA treated with MTX had higher HR and aHR than controls. Patients with ax-SpA are at risk for adhesive capsulitis. When these patients receive SSZ or HCQ, the risk of adhesive capsulitis can be lowered compared with that of the control cohort.

The impact of pre-existing shoulder diseases and traumatic injuries of the shoulder on adhesive capsulitis in adult population: A population-based nested case-control study

Adhesive capsulitis (AC) is a common chronic disorder for adult patients; however, whether a history of pre-existing shoulder diseases may affect the development of AC is still not fully understood. We aimed to investigate the incidence and prevalence of AC and to assess the association of pre-existing shoulder diseases and traumatic injuries of the shoulder with the development of AC in adults.This retrospective population-based cohort and nested case-control study used data from the National Health Institute Research Database of Taiwan. A total of 24,414 patients aged 20 years or older and with a diagnosis of AC were identified between 2000 and 2013. We calculated the incidence of AC for each year during the study period. In addition, these AC patients were matched with controls (n = 97,656) in a ratio of 1:4 based on age, gender, and index date. Univariate and multivariate logistic regression models were performed to identify variables associated with AC.Females and patients aged 50 to 69 years had higher age-gender standardized incidence and prevalence of AC than their counterparts. Multivariate analyses showed that after adjusting for relevant covariates, pre-existing shoulder diseases of calcific tendinitis (odds ratio [OR] = 8.74, 95% confidence interval [CI] = 5.66-13.5), biceps tendinitis (OR = 7.93, 95% CI = 5.33-11.79), rotator cuff syndrome (OR = 6, 95% CI = 5.26-6.85), osteoarthritis (OR = 4.27, 95% CI = 3.44-5.3), and impingement syndrome (OR = 3.13, 95% CI = 2.64-3.71), as well as fracture (OR = 4.51, 95% CI = 3.82-5.34) and dislocation (OR = 3.57, 95% CI = 2.35-5.45) of the shoulder were significantly associated with AC risk.Higher odds of AC were observed among patients with pre-existing shoulder conditions. This study highlights the need to consider differences in AC risk among patients with various types of shoulder diseases and traumatic injuries of the shoulder.

[Primary (idiopathic) shoulder stiffness : Definition, disease progression, epidemiology and etiology]

Shoulder stiffness is characterized by restriction of the active and passive movement of the glenohumeral joint. The stiffness is ultimately caused by fibrosis and the resulting contracture of the glenohumeral joint capsule and its ligaments; however, the term stiff shoulder is only a descriptive umbrella term that must be further defined as the course of the disease and the recommended treatment are decisively influenced by the cause of the shoulder stiffness. Primary shoulder stiffness, also known as idiopathic shoulder stiffness or "frozen shoulder", must be distinguished from various forms of secondary shoulder stiffness and often occurs in three stages, which can all last for several months to years: the initial "freezing phase", followed by a "frozen phase" and finally a "thawing phase". Although primary shoulder stiffness is a frequent pathological alteration with an prevalence of 2-5% in the general population, the exact etiology remains largely unknown; however, there is consensus throughout the literature that certain systemic pathologies, such as diabetes mellitus are associated with a higher incidence of primary shoulder stiffness.

Treatment of Adhesive Capsulitis of the Shoulder

Adhesive capsulitis presents clinically as limited, active and passive range of motion caused by the formation of adhesions of the glenohumeral joint capsule. Radiographically, it is thickening of the capsule and rotator interval. The pathology of the disease, and its classification, relates to inflammation and formation of extensive scar tissue. Risk factors include diabetes, hyperthyroidism, and previous cervical spine surgery. Nonsurgical management includes physical therapy, corticosteroid injections, extracorporeal shock wave therapy, calcitonin, ultrasonography-guided hydrodissection, and hyaluronic acid injections. Most patients will see complete resolution of symptoms with nonsurgical management, and there appears to be a role of early corticosteroid injection in shortening the overall duration of symptoms. Surgical intervention, including manipulation under anesthesia, arthroscopic capsular release both limited and circumferential, and the authors' technique are described in this article. Complications include fracture, glenoid and labral injuries, neurapraxia, and rotator cuff pathology. Postoperative care should always include early physical therapy.

Patient-related Risk Factors for Postoperative Stiffness Requiring Surgical Intervention After Arthroscopic Rotator Cuff Repair

INTRODUCTION

Risk factors for stiffness after arthroscopic rotator cuff repair (RCR) have been limited to studies with small patient numbers. The objective is to determine patient-related risk factors for stiffness after RCR.

METHODS

The PearlDiver database was queried from 2007 to 2015 for patients undergoing isolated arthroscopic RCR. A multivariate binomial logistic regression analysis assessed for risk factors requiring a postoperative manipulation under anesthesia (MUA) or lysis of adhesions (LOA) within 9 months after RCR.

RESULTS

Two hundred thirty-two of 19,229 patients (1.2%) underwent a LOA and/or MUA within 9 months after arthroscopic RCR. Significant risk factors identified were age less than 50 years (odds ratio [OR], 1.9; P < 0.0001), female gender (OR, 2.0; P < 0.0001), diabetes mellitus (DM) type I (OR, 2.7; P < 0.0001), hypothyroidism (OR, 1.3; P = 0.020), and systemic lupus erythematosus (OR, 2.1; P = 0.004). However, tobacco use was associated with a 0.5 risk of developing stiffness (P < 0.0001).

DISCUSSION

Systemic lupus erythematosus, hypothyroidism, and DMI (but not DMII) in addition to young age and female gender were risk factors for LOA/MUA after arthroscopic RCR.

Clinical Results and Complications of Shoulder Manipulation under Ultrasound-Guided Cervical Nerve Root Block for Frozen Shoulder: A Retrospective Observational Study

Introduction

Manipulation under ultrasound-guided fifth and sixth cervical nerve root block (MUC) is a recognized form of treatment for patients with persistent frozen shoulder (FS). This study aimed to investigate the confirmatory hypothesis testing that the MUC has a significant clinical effect on FS refractory to conservative treatments and to assess its adverse events.

Methods

This is a retrospective observational study on patients with FS treated in the past 8 years. Although 77 patients were eligible for this study, only 68 were enrolled. The patients were evaluated immediately before the MUC and at 1, 3, and 6 months after with the use of the Japanese Orthopaedic Association shoulder score. Simultaneously, ranges of motion of the affected shoulder were measured in two directions: forward flexion and external rotation. A paired t test or a Wilcoxon signed-rank test was used to compare differences in outcomes between before and 6 months after MUC. We also assessed any adverse events during and after the MUC.

Results

Regarding the primary outcome, confirmatory testing showed statistically significant improvements in every outcome value at 6 months after MUC (p < 0.001). In terms of adverse events, two patients (2.9%) had vasovagal reflex, one (1.5%) had a panic attack during the block procedure, and a 72-year-old female patient (1.2%) had an avulsion fracture of the inferior glenoid during the manipulation procedure, although all of them recovered spontaneously without any residual functional impairment.

Conclusion

The results showed that significant clinical effects of the MUC on FS were observed through a confirmatory analysis with a sufficient sample size. However, several complications that could occur during the block and manipulation procedures should be considered.

Increased risk of adhesive capsulitis among patients with gout: A nationwide population-based matched-cohort study

AIM

The pathophysiology of adhesive capsulitis (AC) is uncertain. We noted patients with gout seemed to have higher incidence rates of AC than other people in our clinic. We did not know the true relationship between gout and AC because there are no published reports so far. The aim of this study is to verify the risk of developing AC following gout exposure.

METHOD

The authors used the National Health Insurance Research Database of Taiwan to select 39 094 subjects with newly diagnosed gout and randomly extracted 78 188 matched control subjects. All of the subjects in study and control groups were followed until the event of AC. Cox proportional hazard regression analyses were performed to evaluate the subsequent risk of AC.

RESULTS

There was significance since the 8th year of tracking that patients with gout had a higher risk for AC (log-rank test P < .001). Cox regression showed the adjusted hazard ratio of developing AC for patients with gout was 1.71 (95% CI = 1.451-2.565, P < .001) than the control group. Stratified analysis showed that gout patients have a higher risk for AC regardless of diabetes mellitus, stroke or carotid artery disease (P < .05).

CONCLUSIONS

This study showed that gout is an independent risk factor for developing AC.

Rat Model of Adhesive Capsulitis of the Shoulder

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other etiologies of comparable arthrofibrosis. The model includes extra-articular fixation of the shoulder in rats via scapular to humeral suturing, resulting in a secondary contracture without invading the intra-articular space and resulting in decreased rotational ROM and increased joint stiffness. We used 10 Sprague-Dawley rats for the purpose of this study. Baseline ROM measurements were taken before glenohumeral immobilization. The rats were subjected to 8 weeks of immobilization before the fixation sutures were removed and changes in ROM and joint stiffness were evaluated. To evaluate whether immobilization resulted in a significant reduction in ROM, changes in kinematics were calculated. ROM was measured at each time point in the follow-up period and was compared to the baseline internal and external ROM measurements. In order to evaluate the stiffness, joint kinetics were calculated by determining the differences in torque (text and tint ) needed to reach the initial external rotation of 60° and initial internal rotation of 80°. After the removal of the extra-articular suture fixation on follow-up day 0, we found a 63% decrease in total ROM compared to baseline. We observed continuous improvement until week 5 of follow-up, with the progress slowing down around a 19% restriction. On week 8 of follow-up, there was still an 18% restriction of ROM. Additionally, on follow-up day 0, we found the torque increased by 13.3 Nmm when compared to baseline. On week 8, the total torque was measured to be 1.4 ± 0.2 Nmm higher than initial measurements. This work introduces a rat model of shoulder adhesive capsulitis with lasting reduced ROM and increased stiffness.

Asian ethnicity: a risk factor for adhesive capsulitis?

Objective

The aim of this study was to evaluate whether Asian ethnicity is a risk factor for the development of adhesive capsulitis. The secondary aim was to describe the distribution of cases of capsulitis by age group.

Methods

A cross-sectional study comparing the rate of adhesive capsulitis in individuals of Asian ethnicity with that of other ethnicities. We excluded patients with fractures and those with symptoms not involving the shoulder. The odds ratio was adjusted for confounding factors by binary logistic regression.

Results

A total of 1331 patient records were evaluated and after applying the selection criteria, 814 patients remained. We found 134 cases of adhesive capsulitis (15.6%). The peak of incidence was at 60-64 years in the patients of Asian ethnicity and at 55-59 years in the other patients. The unadjusted odds ratio was 4.2 (CI 95%, 2.4-7.4), while the odds ratio adjusted for sex and diabetes mellitus was 3.6 (CI 95%, 2.0-6.5).

Conclusion

Patients of Asian ethnicity showed an independent risk factor for the development of adhesive capsulitis, with an adjusted odds ratio of 3.6. Adhesive capsulitis was more common between 55 and 64 years.

The Association between the Magnetic Resonance Imaging Findings of Adhesive Capsulitis and Shoulder Muscle Fat Quantification Using a Multi-Echo Dixon Method

Objective

To investigate the association between the magnetic resonance imaging (MRI) findings of adhesive capsulitis and shoulder muscle fat percentages using a multi-echo Dixon method.

Materials and Methods

Twenty-four patients with clinical diagnoses of adhesive capsulitis and either intact rotator cuffs or Ellman grade 1 partial tears as indicated by MRI scans were included. Two radiologists independently evaluated MRI scans of adhesive capsulitis as follows: presence or absence of axillary recess capsular and extracapsular hyperintensities; thickness of the coracohumeral ligament; thickness of abnormal rotator interval soft tissue; and thickness of glenoidal/humeral axillary recess capsules. Fat quantifications of the supraspinatus, infraspinatus, teres minor, subscapularis, teres major and posterior deltoid muscles were performed using multi-echo Dixon imaging at three locations. Inter-rater agreement was assessed. Differences in fat percentages were assessed and correlations between fat percentages and quantitative measurements were evaluated.

Results

The fat percentage of the supraspinatus was significantly higher in patients with extracapsular hyperintensity (present, 3.00 ± 1.74%; absent, 1.81 ± 0.80%; p = 0.022). There were positive correlations between the fat percentage of the teres minor and the thicknesses of the abnormal rotator interval soft tissue (r = 0.494, p = 0.014) and the glenoidal axillary recess capsule (r = 0.475, p = 0.019). After controlling for the effects of age, sex and clinical stage, the relationship between the teres minor fat percentage and the thickness of the abnormal rotator interval soft tissue was statistically significant (r = 0.384, p = 0.048). Inter-rater agreement was almost perfect for fat quantification (intraclass correlation coefficients [ICC] > 0.9) and qualitative analyses (k = 0.824), but were variable for quantitative measurements (ICC, 0.170-0.606).

Conclusion

Several MRI findings of adhesive capsulitis were significantly related to higher fat percentages of shoulder muscles.

Risk Factors for Shoulder Stiffness: Current Concepts

Shoulder stiffness is a condition of painful restriction of the glenohumeral range of motion. Numerous risk factors for primary and postoperative shoulder stiffness have been described. This article summarizes the known aspects of the pathophysiology of shoulder stiffness, with special attention to elements of molecular biology and genetics, which could influence the risk of developing shoulder stiffness. Furthermore, the role of hormonal and metabolic factors, medical disorders, drugs, and of other published risk factors for primary and postoperative shoulder stiffness is reviewed and discussed. Finally, aspects related to shoulder surgery and postoperative rehabilitation protocols, which could influence the development of postoperative stiffness are presented.

Subclinical hypothyroidism and diabetes as risk factors for postoperative stiff shoulder

PURPOSE

Postoperative stiffness can be a disabling condition after arthroscopic shoulder surgery. The purpose of this study was to analyse the potential contribution of subclinical forms of hypothyroidism and diabetes in the development of postoperative shoulder stiffness.

METHODS

A prospective study was conducted on 65 consecutive patients scheduled for arthroscopic subacromial decompression or rotator cuff tear repair. Patients with preoperative stiffness were excluded. Preoperative measurements of free thyroxine, free triiodothyronine, thyroid-stimulating hormone and fasting glycaemia were taken in all patients to detect subclinical forms of diabetes and hypothyroidism. A follow-up was planned at 30, 60, 90 and 180 days after surgery. According to range of motion measurements, postoperative stiffness was classified as severe or moderate at follow-up. Univariate and logistic regression analyses were performed for the assessment of risk factors for stiffness.

RESULTS

The overall incidence of postoperative stiffness was 29 % (19/65) in our cohort. Considering only the arthroscopic rotator cuff repairs, this incidence was 23 % (7/31). A new diagnosis of subclinical forms of diabetes or hypothyroidism was made in five cases. All five of these cases developed postoperative stiffness. The logistic regression analysis demonstrated that hypothyroidism was a risk factor for severe stiffness (RR = 25; p = 0.001) and that diabetes was a risk factor for moderate stiffness (RR = 5.7; p = 0.03).

CONCLUSION

The postoperative stiffness in the majority of patients can be predicted by a careful analysis of past medical history and by detecting subclinical forms of hypothyroidism and diabetes.

LEVEL OF EVIDENCE

Prognostic study, Level II.

Adhesive capsulitis of the shoulder: review of pathophysiology and current clinical treatments

Adhesive shoulder capsulitis, or arthrofibrosis, describes a pathological process in which the body forms excessive scar tissue or adhesions across the glenohumeral joint, leading to pain, stiffness and dysfunction. It is a debilitating condition that can occur spontaneously (primary or idiopathic adhesive capsulitis) or following shoulder surgery or trauma (secondary adhesive capsulitis). Here, we review the pathophysiology of adhesive shoulder capsulitis, highlighting its clinical presentation, natural history, risk factors, pathoanatomy and pathogenesis. Both current non-operative and operative treatments for adhesive capsulitis are described, and evidence-based studies are presented in support for or against each corresponding treatment. Finally, the review also provides an update on the gene expression profile of adhesive capsulitis and how this new understanding can help facilitate development of novel pharmacological therapies.

Generation and characterization of a novel shoulder contracture mouse model

Frozen shoulder is a relatively common disorder that leads to severe pain and stiffness in the shoulder joint. Although this disorder is self-limiting in nature, the symptoms often persist for years, resulting in severe disability. Recent studies using human specimens and animal models have shown distinct changes in the gene expression patterns in frozen shoulder tissue, indicating that novel therapeutic intervention could be achieved by controlling the genes that are potentially involved in the development of frozen shoulder. To achieve this goal, it is imperative to develop a reliable animal joint contracture model in which gene expression can be manipulated by gene targeting and transgenic technologies. Here, we describe a novel shoulder contracture mouse model. We found that this model mimics the clinical presentation of human frozen shoulder and recapitulates the changes in the gene expression pattern and the histology of frozen shoulder and joint contracture in humans and other larger animal models. The model is highly reproducible, without any major complications. Therefore, the present model may serve as a useful tool for investigating frozen shoulder etiology and for identifying its potential target genes.