Biological factors in the pathogenesis of rotator cuff tears

Arthroscopic management of isolated partial-thickness rotator cuff tears

PURPOSE

The aim of the present study is to provide a comprehensive review on the surgical outcomes following arthroscopic treatments of partial-thickness rotator cuff tears (PT-RCTs) and to compare the postoperative American Shoulder and Elbow Surgeons (ASES) score following in situ transtendon repair and tear completion, followed by repair.

METHODS

Medline, EMBASE, Scopus, CINAHL and CENTRAL bibliographic databases were searched. Papers including patients with PT-RCTs of any grade who underwent treatment using debridement, in situ transtendon repair, tear completion and repair or bioinductive collagen implants were reviewed. Primary PT-RCTs were the sole indication for surgery. Primary postoperative outcomes assessed included the ASES score, the Absolute Constant-Murley score, the Simple Shoulder Test, the Visual Analogue Scale, the University of California-Los Angeles Shoulder Scale, the Western Ontario Rotator Cuff Score, range of motion, complications and revisions. A meta-analysis of comparative studies compared the postoperative ASES score between patients treated with in situ transtendon repair versus tear completion repair.

RESULTS

Twenty-eight studies were included. The ASES score was reported by four comparative studies with contrasting results. The heterogeneity was high (I2 = 86%), and effect sizes ranged from -0.49 in favour of the tear completion and repair technique to an effect size of +1.07 favouring in situ transtendon repair. The overall effect size of 0.02 suggests an equivalence between the two techniques in terms of the ASES score. Two studies with a total sample size of 111 patients reported on debridement, and four studies with a total sample size of 155 patients reported on bioinductive collagen implants.

CONCLUSION

Debridement alone is suitable for Ellman grades I-II PT-RCTs. In situ transtendon and tear completion repair techniques yield similar postoperative outcomes. Bioinductive collagen implants hold promise but lack long-term efficacy data. High-quality comparative studies are needed to determine the best treatment for PT-RCTs.

LEVEL OF EVIDENCE

Level IV.

Preoperative Increases in T2-Weighted Fat-Suppressed MRI Signal Intensities Associated with Advanced Tissue Degeneration and Mitochondrial Dysfunction in Rotator Cuff Tears

PURPOSE

The purpose of this study was to investigate the relationship between magnetic resonance imaging (MRI) signal intensities and mitochondrial function in patients undergoing arthroscopic rotator cuff repair, assessed through histological and genetic profiling of tendon tissue.

METHODS

This study, conducted between April 2022 and January 2023, included 20 patients undergoing rotator cuff repair for atraumatic/degenerative tears. Rotator cuff tendon edge samples were obtained during arthroscopic rotator cuff repair. Patients were classified based on signal intensity from preoperative T2-weighted fat suppressed MRI. Specifically, they were categorized as having either high or low signal intensity at the rotator cuff tendon edge, with the deltoid muscle serving as a reference. Comparative analyses specifically compared the histological features and genetic profiles of the tendon tissue at the rotator cuff tendon edge. Histological evaluation of harvested tendon specimens during arthroscopic rotator cuff repair employed the modified Bonar score. Real-time polymerase chain reaction was used to assess expression of various mitochondrial and apoptosis-related genes. The mitochondrial morphology of the rotator cuff torn site was examined using electron microscopy.

RESULTS

The higher signal intensity group showed significantly higher modified Bonar scores (p=0.0068), decreased mitochondrial gene expression, increased TUNEL-positive cells (p=0.032), lower SOD activity (p=0.011), reduced ATP5A (p=0.031), and increased cleaved caspase-9 activity (p=0.026) when compared to the lower signal intensity group. Electron microscopy revealed fewer mitochondrial cristae in the higher signal intensity group.

CONCLUSION

Our results suggest correlations between high MRI signal intensities and the presence of degeneration, mitochondrial dysfunction, and increased apoptosis in rotator cuff tissues. This underscores the utility of MRI signal intensity as an indicator of tissue condition.

CLINICAL RELEVANCE

Building on the established premise that elevated preoperative MRI signal intensities may indicate higher rates of postoperative rotator cuff re-tears, the current study substantiates these findings from a mitochondrial function perspective.

Imaging of glenohumeral osteoarthritis: Reliability and reproducibility of radiological classifications

BACKGROUND

Glenohumeral degenerative joint disease may affect up to 20% of the population. There are several classification systems of this disease in the scientific literature.

OBJECTIVE

The aim of this study is to determine the reliability and reproducibility of glenohumeral osteoarthritis classification systems.

METHODS

We assessed glenohumeral plain radiographs performed in a University Hospital. These radiographs were graded into nine radiological classification systems by two observers on two evaluations. Patients who have performed CT/MRI scan were staged according to the Walch classification. The intra-observer and inter-observer reliability of the classification schemes were determined by using Cohen's weighted kappa coefficient.

RESULTS

A total of 752 patients were included in the study (52.4% females and 47.6% males), mean aged 66.2 ± 16.3 years. The intra-observer and inter-observer reliabilities were 0.543 (observer 1), 0.630 (observer 2), and 0.760 (inter-observer) for the Weinstein grading system; 0.661, 0.706, and 0.761 for the Guyette grading system; 0.575, 0.679 and 0.704 for the Kellgren and Lawrence classification; 0.817, 0.816 e 0.871 for the Samilson and Prieto classification; 0.791, 0.811 and 0.847 for the Allain modification; 0.797, 0.842 and 0.860 for the Gerber modification; 0.773, 0.827 and 0.828 for the Buscayret modification; 0.584, 0.648 and 0.755 for the Hawkins and Angelo classification; 0.661, 0.749 and 0.764 for the Rosenberg classification. Intra-observer reliability for MRI was 0.757 (observer 1) and 0.675 (observer 2), while intra-observer reliability for CT was 0.811 (observer 1) and 0.653 (observer 2). Inter-observer reliabilities were 0.790 for MRI and 0.673 for CT.

CONCLUSION

The classification systems according to Weinstein, Guyette, Hawkins and Angelo, Rosenberg and the modifications of the Samilson and Prieto classification according to Allain, Gerber and Buscayret showed a comparable reliability with the commonly used glenohumeral osteoarthritis grading systems, Samilson and Prieto and Kellgren and Lawrence. Thus, they are recommended for clinical and especially scientific purposes.

Six-Degree-of-Freedom Freehand 3D Ultrasound: A Low-Cost Computer Vision-Based Approach for Orthopedic Applications

In orthopedics, X-rays and computed tomography (CT) scans play pivotal roles in diagnosing and treating bone pathologies. Machine bulkiness and the emission of ionizing radiation remain the main problems associated with these techniques. The accessibility and low risks related to ultrasound handling make it a popular 2D imaging method. Indeed, 3D ultrasound assembles 2D slices into a 3D volume. This study aimed to implement a probe-tracking method for 6 DoF 3D ultrasound. The proposed method involves a dodecahedron with ArUco markers attached, enabling computer vision tracking of the ultrasound probe's position and orientation. The algorithm focuses on the data acquisition phase but covers the basic reconstruction required for data generation and analysis. In the best case, the analysis revealed an average error norm of 2.858 mm with a standard deviation norm of 5.534 mm compared to an infrared optical tracking system used as a reference. This study demonstrates the feasibility of performing volumetric imaging without ionizing radiation or bulky systems. This marker-based approach shows promise for enhancing orthopedic imaging, providing a more accessible imaging modality for helping clinicians to diagnose pathologies regarding complex joints, such as the shoulder, replacing standard infrared tracking systems known to suffer from marker occlusion problems.

I Am Afraid I Will Not Be Able to Walk, That Is What Worries Me-The Experience of Patients with Knee Osteoarthritis before Total Knee Arthroplasty: A Qualitative Study

Background: Knee osteoarthritis is the most prevalent type of osteoarthritis. Patients frequently encounter pain triggered by movement that evolves into impaired joint function. Needing persistent rest or having night-time pain signifies advanced disease. Qualitative research is considered the most effective method for comprehending patients' needs and contexts. Methods: This study employed a qualitative research design, allowing the researchers to acquire insights into the patients' beliefs and values, and the contextual factors influencing the formation and expression of these beliefs and values. Results: A cohort of nine patients awaiting total knee replacement (TKR) surgery was included and they were interviewed until data saturation was achieved. The results of the phenomenological analysis resulted in the identification of three themes: "The existence of pain impedes the capacity to participate in daily life activities"; "TKR induced fears and uncertainties regarding the progression of the disease"; "Severe nighttime pain compromising sleep quality". Conclusions: This study analyzes the experiences of people awaiting TKR surgery, emphasizing the importance of addressing their unique needs to improve preoperative education and rehabilitation. In this way, patients' recovery during the postoperative phase can be improved.

Performance Evaluation of an Immersive Virtual Reality Application for Rehabilitation after Arthroscopic Rotator Cuff Repair

Few studies have evaluated the effectiveness of shoulder rehabilitation in virtual environments. The objective of this study was to investigate the performance of a custom virtual reality application (VR app) with a stereophotogrammetric system considered the gold standard. A custom VR app was designed considering the recommended rehabilitation exercises following arthroscopic rotator cuff repair. Following the setting of the play space, the user's arm length, and height, five healthy volunteers performed four levels of rehabilitative exercises. Results for the first and second rounds of flexion and abduction displayed low total mean absolute error values and low numbers of unmet conditions. In internal and external rotation, the number of times conditions were not met was slightly higher; this was attributed to a lack of isolated shoulder movement. Data is promising, and volunteers were able to reach goal conditions more often than not. Despite positive results, more literature comparing VR applications with gold-standard clinical parameters is necessary. Nevertheless, results contribute to a body of literature that continues to encourage the application of VR to shoulder rehabilitation programs.

Immersive virtual reality for shoulder rehabilitation: evaluation of a physical therapy program executed with oculus quest 2

BACKGROUND

Virtual Reality (VR) systems have been increasingly used across several medical fields. A crucial preliminary step for developing optimized VR-based applications for rehabilitation purposes is identifying potential interventions to meet the requirements necessary to satisfy end-users' needs. This study aims to assess the acceptability, usability, and appropriateness of a VR physical therapy program executed with Oculus Quest 2 by expert physiotherapists of shoulder musculoskeletal rehabilitation.

METHODS

Eleven physiotherapists were enrolled to test a VR program for shoulder musculoskeletal rehabilitation. At the end of each session, physiotherapists completed three questionnaires about the acceptability, usability, and appropriateness of the VR system and application, investigating aspects such as wearability, safety, stability, ease of control, comfort, size, utility, playability, and use mode.

RESULTS

The acceptability questionnaire revealed that all the physiotherapists found the VR system easy to wear and control, very confident, and safe. The usability questionnaire showed that most physiotherapists (73%) found the VR application entertaining, although only 45% said the system could be used independently by patients without the support of a therapist. Many physiotherapists found the use of the VR application appropriate for patients with rotator cuff tears treated conservatively (63.6%) or surgically (54.5%), for patients with shoulder osteoarthritis treated conservatively (72.7%), for patients with shoulder osteoarthritis after surgical treatment (63.6%). 91% of physiotherapists think it would be best for patients to use the VR system under the supervision of a therapist and not independently in a home setting.

CONCLUSIONS

The use of VR in orthopaedic rehabilitation is encouraging, although further efforts are needed to increase the independent use of patients without the supervision of a physiotherapist. Moreover, future studies should strive to ensure the clinical effectiveness of VR rehabilitation in reaching therapeutic goal settings.

MRI is a Reliable Method for Measurement of Critical Shoulder Angle and Acromial Index

Objective  The objectives of this study are to compare absolute values of acromial index (AI) and critical shoulder angle (CSA) obtained in both radiographs and magnetic resonance image (MRI) of the shoulder; and to compare the interobserver and intra-observer agreement for AI and CSA values measured in these image modalities. Methods  Patients who had medical indication of investigating shoulders conditions through radiographs and MRI were included. Images were taken to two fellowship-trained shoulder surgeons, which conducted measurements of AI and CSA in radiographs and in MRI. Twelve weeks after the first evaluation, a second evaluation was conducted. Inter- and intra-observer reliability was presented as an Intraclass Correlation Coefficient (ICC) and agreement was classified according to Landis & Koch criteria. The differences between two measurements were evaluated using Bland-Altman plots. Results  134 shoulders in 124 subjects were included. Mean intra-observer ICC for CSA in X-rays and in MRI were 0.936 and 0.940, respectively; for AI, 0.908 and 0.022. Mean inter-observer ICC for CSA were 0.892 and 0.752 in X-rays and MRI respectively; for AI, ICC values were 0.849 and 0.685. All individual analysis reached statistical power ( p  < 0.001). Mean difference for AI values measured in X-rays and in MRI was 0.01 and 0.03 for observers 1 and 2, respectively. Mean difference for CSA values obtained in X-rays and MRI was 0.16 and 0.58 for observers 1 and 2, respectively. Conclusion  Both MRI and X-rays provided high intra- and interobserver agreement for measurement of AI and CSA. Absolute values found for AI and CSA were highly correlated in both image modalities. These findings suggest that MRI is a suitable method to measure AI and CSA. Level of Evidence II , Diagnostic Study.

Application of Machine Learning Algorithms for Prognostic Assessment in Rotator Cuff Pathologies: A Clinical Data-Based Approach

AIM

The overall aim of this proposal is to ameliorate the care of rotator cuff (RC) tear patients by applying an innovative machine learning approach for outcome prediction after arthroscopic repair.

MATERIALS AND METHODS

We applied state-of-the-art machine learning algorithms to evaluate the best predictors of the outcome, and 100 RC patients were evaluated at baseline (T0), after 1 month (T1), 3 months (T2), 6 months (T3), and 1 year (T4) from surgical intervention. The outcome measure was the Costant-Murley Shoulder Score, whereas age, sex, BMI, the 36-Item Short-Form Survey, the Simple Shoulder Test, the Hospital Anxiety and Depression Scale, the American Shoulder and Elbow Surgeons Score, the Oxford Shoulder Score, and the Shoulder Pain and Disability Index were considered as predictive factors. Support vector machine (SVM), k-nearest neighbors (k-NN), naïve Bayes (NB), and random forest (RF) algorithms were employed.

RESULTS

Across all sessions, the classifiers demonstrated suboptimal performance when using both the complete and shrunken sets of features. Specifically, the logistic regression (LR) classifier achieved a mean accuracy of 46.5% ± 6%, while the random forest (RF) classifier achieved 51.25% ± 4%. For the shrunken set of features, LR obtained a mean accuracy of 48.5% ± 6%, and RF achieved 45.5% ± 4.5%. No statistical differences were found when comparing the performance metrics of ML algorithms.

CONCLUSIONS

This study underlines the importance of extending the application of AI methods to new predictors, such as neuroimaging and kinematic data, in order to better record significant shifts in RC patients' prognosis.

LIMITATIONS

The data quality within the cohort could represent a limitation, since certain variables, such as smoking, diabetes, and work injury, are known to have an impact on the outcome.

Scapular Kinematics and Patterns of Scapular Dyskinesis in Rotator Cuff Tears: A Prospective Cohort Study

Scapular dyskinesis (SD) is a condition of loss of normal mobility or function of the scapula. SD is frequently observed in patients with other shoulder disorders, such as rotator cuff (RC) tears. This study evaluates the different presentations in clinical outcomes and range of motions (ROMs) in patients suffering from RC tears with and without SD. A total of 52 patients were enrolled, of which 32 patients with RC tears and SD (group A) and 20 patients with RC tears without SD (group B). Statistically significant differences between the groups in terms of clinical outcomes were identified. There were statistically significant differences in terms of flexion (p = 0.019), extension (p = 0.015), abduction (p = 0.005), and external rotation at 90° (p = 0.003) and at 0° (p = 0.025). In conclusion, this prospective study demonstrated that SD influences the clinical presentation of patients with RC tears in terms of clinical outcomes and ROMs, apart from internal rotation. Further studies will need to show whether these differences occur regardless of SD type.

Investigation the Effect of Human Recombinant Epidermal Growth Factor on Rotator Cuff Healing: An Experimental Model

Objective  To investigate the effectiveness of human recombinant epidermal growth factor in the healing of rotator cuff tear in the rabbit shoulder. Methods  Rotator cuff tears (RCTs) were experimentally created on both shoulders of 20 New Zealand rabbits. The rabbits were divided into the following groups: RCT (sham group; n  = 5), RCT + EGF (EGF group; n  = 5), RCT + transosseous repair (repair group; n  = 5), and RCT + EGF + transosseous repair (combined repair + EGF group; n  = 5). All rabbits were then observed for 3 weeks, and biopsies were taken from the right shoulders in the third week. After three more weeks of observation, all rabbits were sacrificed, and a biopsy removed from their left shoulders. All biopsy material was stained with haematoxylin & eosin (H&E) and vascularity, cellularity, the proportion of fibers and the number of fibrocartilage cells were evaluated under light microscope. Results  The highest collagen amount and the most regular collagen sequence was detected in the combined repair + EGF group. The repair group and the EGF group showed higher fibroblastic activity and capillary formation when compared with the sham group, but the highest fibroblastic activity and capillary formation with highest vascularity was detected in the combined repair + EGF group ( p  < 0.001). EGF seems to improve wound healing in the repair of RCT. The EGF application alone, even without repair surgery, seems to be beneficial to RCT healing. Conclusion  In addition to rotator cuff tear repair, application of human recombinant epidermal growth factor has an effect on rotator cuff healing in rabbit shoulders.

Humeral and Glenoid Version in Reverse Total Shoulder Arthroplasty: A Systematic Review

There is increasing interest in reverse total shoulder arthroplasty (RTSA) as a reliable treatment for arthritic, rotator cuff deficient shoulders. Humeral and glenoid version are controversial parameters that can influence internal and external rotation, muscular forces, and implant stability as outcomes of RTSA. The aim of this study was to obtain an overview of the current knowledge on the effect of both humeral component version and glenoid component version and give recommendations on their most optimal degree for RTSA. A comprehensive quantitative review of the published literature on the effect of humeral version and glenoid version in RTSA was performed, to identify its influence on the range of movement, muscle forces, and intrinsic stability of the reverse prosthesis. Eleven studies were included: nine were biomechanical studies, one was a clinical-radiographic study, and one was an implant design consideration. Anterior stability can be improved by implanting the humeral component in neutral or with some anteversion. Glenoid component retroversion has been proven to reduce the likelihood of subluxation, while increasing ER and ROM at the same time. The study was conducted considering 5° anteversion; neutral; and 5°, 10°, and 20° retroversion of the glenoid component. Although a final opinion has not been yet expressed on the matter, the general consensus tends to agree on restoring 0° to 20° of retroversion of the humeral and glenoid component to yield the best outcomes.

Genome-Wide Association Study Identifies Genetic Variants Associated with Rotator Cuff Tear-A Pilot Study

A rotator cuff is a muscle and tendon surrounding the shoulder joint, and a rotator cuff tear can be caused by overuse or injury, which leads to great pain in affected individuals. However, rotator cuff tear is a multifactorial process whose underlying mechanism is still unclear. Many previous studies have suggested an important role of genetic predisposition, such as single-nucleotide polymorphisms (SNPs), in explaining the genesis of tendinopathy. This study aimed to identify specific genes or genetic variants associated with rotator cuff tears by performing a genome-wide association study (GWAS) using an independent case of rotator cuff tears. GWAS was performed using data from CHA Bundang Medical Center with 20 cases of rotator cuff tears, and 20 cases of healthy controls genotyped on the Illumina HiSeq 2500. Tests of association were performed using the Burrows−Wheeler Aligner (BWA) software at 284,246 SNPs. Data were filtered based on sequence ontology, minor allele frequency, and Hardy−Weinberg equilibrium values, and SNPs were considered significant if the p-value was <0.05. The tests of association revealed more than 20 significantly associated SNPs. SNPs showing the highest significance occurred in candidate genes, including LAIR2 (rs2287828, OR 9.116, p-value 5.49 × 10−4) on chromosome 19 and CRIPAK (rs9328733, OR 6, p-value 1.11 × 10−3) and REST (rs2228991, OR 8.222, p-value 1.20 × 10−3) on chromosome 4. This study attempted to identify genetic variants influencing rotator cuff tears through a genome-wide association study using a dense set of SNPs. More than 20 SNPs were significantly associated with rotator cuff tears. The major limitation of this study is that it was conducted on a small study group and requires further validation. Nevertheless, the identification of potential genetic variants related to rotator cuff injury would aid in the early detection of individuals at risk for the development of tendinopathy and will provide insight into future gene therapies.

Evaluation of oxidative stress in degenerative rotator cuff tears

BACKGROUND

Oxidative stress occurs as a result of the disruption of the balance between the formations of reactive oxygen species and antioxidant defense mechanisms during the conversion of nutrients into energy. Increased body oxidative stress has been reported to be involved in the etiology of several degenerative and chronic diseases. We hypothesized that the body oxidative stress level is higher in patients with atraumatic degenerative rotator cuff tear than that in healthy individuals.

METHODS

The patients who underwent arthroscopic repair for atraumatic, degenerative rotator cuff tear were prospectively evaluated. A total of 30 patients (group 1, 19 females and 11 males; mean age: 57.33 ± 6.96 years; range: 50-77 years) and 30 healthy individuals (group 2, 18 females and 12 males; mean age: 56.77 ± 6 years; range: 51-72 years) were included in the study. The Constant and American Shoulder and Elbow Surgeons scoring systems were used to evaluate the clinical outcomes. Serum oxidative stress parameters of the patients and the control group were biochemically evaluated. Accordingly, thiol/disulfide (DS) balance (DS/native thiol [NT], DS/total thiol [TT]), Total Oxidant Status (TOS), oxidative stress index, and nuclear factor erythroid-2-associated factor-2 values were used as the biochemical parameters indicating an increase in the serum oxidative stress level. Total antioxidant status and NT/TT values served as the biochemical parameters indicating a decrease in the serum oxidative stress level.

RESULTS

The study follow-up duration was 12 months. A statistically significant increase was observed in American Shoulder and Elbow Surgeons and Constant scores of patients who underwent arthroscopic rotator cuff repair relative to that during the preoperative period (P = .01). The values of biochemical parameters (DS/NT, DS/TT, TOS, oxidative stress index, and nuclear factor erythroid-2-associated factor-2), which indicated an increase in the serum oxidative stress, were significantly higher in preoperative patients than those in postoperative patients, albeit the control group values were significantly lower than those of the postoperative patients. The biochemical parameters (NT/TT and total antioxidant status) indicating a decrease in the serum oxidative stress levels were significantly higher in the postoperative patients than those in the preoperative patients and significantly lower than those in the control group.

CONCLUSION

High levels of markers indicating an increase in the serum oxidative stress in patients with degenerative rotator cuff rupture suggested that TOS may be involved in the etiopathogenesis of rotator cuff degeneration. Although the oxidative load decreases during the postoperative period, the fact that it is still higher than that in healthy individuals supports this claim.

A lipid metabolite lipidomics assay for prediction and severity evaluation of rotator cuff injury

Objective

Rotator cuff injury can be caused by local inflammation and fibrosis of musculotendinous cuff. Hypercholesterolemia can lead to physiological changes of rotator cuff that resemble rotator cuff injury. However, the relationship between lipid metabolism and rotator cuff injury and its potential pathological mechanism remain unclear. Herein, we aimed to investigate the correlation between the plasma lipidome, rotator cuff injury, and successive fatty infiltration pathology, and hoped to identify biomarkers for predicting higher risk or higher severity rotator cuff injury by assessing metabolic perturbations and dyslipidemia using lipidomics.

Methods

We quantitatively analyzed 60 lipids species of seven lipids classes and subclasses from 66 subjects using lipidomics. Subjects were divided into four groups: (1) normal rotator cuff with normal clinical routine serum lipid test results (NN group = 13); (2) normal rotator cuff with abnormal clinical routine serum lipid test results (NA group = 10); (3) rotator cuff tear with normal routine serum lipid test results (RN group = 30); (4) rotator cuff tear with abnormal routine serum lipid test results (RA group = 13). Independent-sample t-tests and Kruskal-Wallis tests were used to compare lipid metabolite levels in serum between different groups in patients with rotator cuff tears. The orthogonal partial least squares-discriminant analysis (OPLS-DA) model was used to verify the ability of five lysophosphatidylcholines (LPCs) to distinguish rotator cuff injuries. In the rotator cuff tear group, magnetic resonance imaging (MRI) was used to classify fatty infiltration according to Goutallier's classification. Kruskal-Wallis tests were used to analyze molecular differences between high-grade (grade 3–4) and low-grade (grade 0–2) fatty infiltration groups. Receiver operator characteristic (ROC) curves were drawn for each diagnostic method via different metabolites. The area under the curve (AUC), cutoff, specificity, sensitivity, and accuracy of each diagnostic criterion were calculated.

Results

Our results showed that some rotator cuff injury patients yielded unique lipidomic profiles. Based on Kruskal-Wallis tests, our results showed significant differences in three lipid molecules, 17:1 Lyso PI, 18:0–22:6 PE, and 18:3 (Cis) PC, among all four groups independent of clinical blood lipid levels. Also, independent of clinical blood lipid levels, two lipid molecules, 22:0 Lyso PC and 24:0 Lyso PC, were significantly different between the two groups based on Independent sample t-tests. Kruskal-Wallis test results showed that in the rotator cuff tear group, two metabolites (24:0 SM and 16:0 ceramide) differed between high-grade and low-grade fatty infiltration. The AUC values for 22:0 Lyso PC, 24:0 Lyso PC, 18:0–22:6 PE, 24:0 SM, and 16:0 ceramide were 0.6036, 0.6757, 0.6712, 0.8333, and 0.8981, respectively.

Conclusion

The results provide insight into how the metabolic mechanisms associated with dyslipidemia impact rotator cuff diseases. Five lipid molecules, 17:1 Lyso PI, 18:0–22:6 PE, 18:3 (Cis) PC, 22:0 Lyso PC, and 24:0 Lyso PC, were closely related to rotator cuff tear based on two statistical analysis methods, independent of clinical routine serum lipid test results, which indicates that lipidomics assays are more sensitive than conventional lipid tests, and more suitable for studying rotator cuff lipid metabolism. In addition, two lipid metabolites, 24:0 SM and 16:0 ceramide, are potentially useful for predicting fatty infiltration severity. Further research with a larger number of samples is needed to verify whether these two metabolites can serve as potential markers of severe fatty infiltration. The findings illuminate how metabolic mechanisms associated with dyslipidemia affect rotator cuff disease.

Relationship of superoxide dismutase to rotator cuff injury/tear in a rat model

Rotator cuff degeneration is one of the several factors that lead to rotator cuff tears. Oxidative stress and superoxide dismutase have been reported to be related to rotator cuff degeneration; however, the precise mechanism still remains unclear. In this study, we investigated the relationship of oxidative stress and superoxide dismutase to the degeneration of the rotator cuff using rat models. Eighty-four rats were used to create a collagenase-induced rotator cuff injury model (injury model) and a rotator cuff tear model (tear model). The controls were administered saline and had only a deltoid incision, respectively. We evaluated degeneration morphology of the rotator cuff using a degeneration score; dihydroethidium fluorescence intensity, which detects oxidative stress; gene expression; and superoxide dismutase activity. The rotator cuffs in the injury and tear models significantly increased degeneration scores and dihydroethidium fluorescence intensity. On the other hand, gene expression of superoxide dismutase isoform, superoxide dismutase 1, and superoxide dismutase activity were significantly decreased in the injury model but showed no significant difference in the tear model. These findings suggested that superoxide dismutase might not be associated with rotator cuff degeneration after tear but may be involved in degenerative rotator cuff without tear. However, we found that rotator cuff degeneration involves oxidative stress both with and without tear. Based on these findings, it is presumed that different treatments may be appropriate, depending on the state of rotator cuff degeneration, because the mechanisms of the degeneration may be different.

Editorial Commentary: Sleep Disorders in Rotator Cuff Diseases

One of the most common complaints expressed by patients with rotator cuff disease is poor-quality sleep. Sleeping significantly affects daily life, influencing biological functions, learning, memory, and cognitive processes. The etiology of nocturnal shoulder pain is controversial, yet there is a consensus that high levels of proinflammatory factors and pain-related cytokines are involved in the pathogenesis of this disturbance in patients with shoulder rotator cuff pathology. Unfortunately, many variables, including body mass index, depression, sex, low back pain, cervical pain, diabetes, narcotics, pain, pain perception, and sleeping position (which may influence tendon perfusion), could influence sleep quality in both healthy patients and patients with rotator cuff pathology. For now, it is not possible to assess the real influence of rotator cuff repair surgery on sleep quality improvement.

Full-Thickness Rotator Cuff Tears Can Be Safely Treated With a Resorbable Bioinductive Bovine Collagen Implant: One-Year Results of a Prospective, Multicenter Registry

Purpose

The purpose of this study was to prospectively collect safety and efficacy data in a large group of patients undergoing arthroscopic repair of full-thickness rotator cuff tears augmented with a resorbable bioinductive bovine collagen implant designed to promote healing.

Methods

Seventeen centers across the United States enrolled patients in an institutional review board-approved registry to collect outcomes data on the implant. Patients undergoing surgical management of full-thickness rotator cuff tears augmented with the implant were enrolled. Inclusion criteria were age of ≥21 years, willingness to participate and the ability to read and speak English. Exclusion criteria included hypersensitivity to bovine-derived products. Patients were assessed before and after surgery at up to 1 year with outcomes including the single-assessment numeric evaluation (SANE), Veterans RAND 12-Item (VR-12) mental components and physical components (VR-12 PCS), American Shoulder and Elbow Surgeons (ASES), and Western Ontario Rotator Cuff (WORC) outcome measures. Ad hoc analyses were performed to compare these outcomes at all time points depending on tear size (small/medium vs large/massive). Serious complications were collected.

Results

Of 210 patients enrolled, 192 had 1-year follow-up data available. The patients experienced statistically significant improvement between baseline and 1 year for mean SANE, VR-12 PCS, ASES, and WORC scores (40.0-82.0, 33.5-47.3, 46.2-87.8, and 36.2-81.0, respectively; P < .001 for all results). Ad-hoc analysis demonstrated that similar results were obtained at 1 year regardless of tear size. Twenty patients (10.4%) experienced serious complications (10.4%), including revision surgery (n = 18), proximal humerus fracture/partial subscapularis tear resulting from multiple falls (n = 1), and adhesive capsulitis (n = 1).

Conclusions

The safety and efficacy of a bioinductive implant in the surgical management of full-thickness rotator cuff tears at 1 year was shown in this study. Implant efficacy appears to be comparable regardless of the underlying tear size.

Level of Evidence

Level IV, therapeutic case series.

Conservative versus accelerated rehabilitation after rotator cuff repair: a systematic review and meta-analysis

Background

The purpose of this systematic review and meta-analysis is to compare the conservative and accelerated rehabilitation protocols in patients who underwent arthroscopic rotator cuff repair in terms of clinical outcomes and range of motions at 3, 6, 12, and 24-month follow-up.

Methods

According to PRISMA guidelines, a systematic review of the literature was performed. For each included article, the following data has been extracted: authors, year, study design, level of evidence, demographic characteristics, follow-up, clinical outcomes, range of motions, and retear events. A meta-analysis was performed to compare accelerated versus conservative rehabilitation protocols after arthroscopic rotator cuff repair. The retear rate, postoperative Constant-Murley score and range of motions at 3, 6, 12, and 24 months of follow-up were the outcomes measured.

Results

The search strategy yielded 16 level I-II clinical studies. A total of 1424 patients, with 732 patients and 692 in the accelerated and conservative group, were included. The average age (mean ± standard deviation) was 56.1 ± 8.7 and 56.6 ± 9 in the accelerated and conservative group. The mean follow-up was 12.5 months, ranging from 2 to 24 months. The meta-analysis showed no statistically significant differences in terms of retear rate between the groups (P = 0.29). The superiority of the accelerated group was demonstrated in terms of external rotation (P < 0.05) at 3-month follow-up; in terms of forward elevation, external rotation, abduction (P < 0.05), but not in terms of Constant-Murley score at 6-month follow-up; in terms of forward elevation (P < 0.05) at 12-month follow-up. No significant differences between the two group were highlighted at 24-month follow-up.

Conclusions

No statistically significant differences in the retear rate among the accelerated and conservative group have been demonstrated. On the other hand, statistically and clinically significant differences were found in terms of external rotation at 3 and 6 months of follow-up in favour of the accelerated group. However, no differences between the two groups were detected at 24 months follow-up.

The influence of psychosocial factors on patient-reported outcome measures in rotator cuff tears pre- and post-surgery: a systematic review

PURPOSE

Recent research shows that major levels of psychological distress correlate with higher pain and reduced function in patients with shoulder and rotator cuff pathology. A systematic review updating a review published in 2016 was conducted to determine the degree of consistency and the strength of association between psychosocial factors and patient-reported outcomes (PROMs) in patients with rotator cuff repair (RCR) with new high-quality literature.

METHODS

The bibliographic searches were conducted from May to June 2020 within the following databases: MEDLINE/PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, and Web of Science. The articles included should discuss the association between psychosocial factors and outcomes in patients with documented or diagnosed rotator cuff tears through clinical and/or radiological examination. The Methodological Index for Non-Randomized Studies (MINORS) tool was used to assess the methodological quality.

RESULTS

Fifteen articles were included. Negative psychosocial factors were found consistently associated with worse function and disability in the pre- and post-operative period. In particular, psychosocial factors regarding emotional or mental health were associated with a weak to a substantial degree with preoperative and postoperative function/disability and pain intensity in patients undergoing RCR.

CONCLUSION

In patients undergoing repair of the rotator cuff tear, there was a correlation between poor psychological function before surgery and worsening post-surgical outcomes, such as persistence of postoperative pain intensity and worse levels of function/disability.

Nuclear lamin A in rotator cuff tear margin tenocytes: an antiapoptotic and cell mechanostat factor

Background

The network of intermediate filament proteins underlying the inner nuclear membrane forms the nuclear lamin. A- and B-type lamins are the major components of the nuclear lamina. Lamins function in many nuclear activities. The role of lamin A and transcription factors (NF-kB) as anti-apoptotic is well documented. Recently, lamin A has also been considered as a mechanosensor protein that is able to maintain nuclear integrity from mechanical insults.

We aimed to verify how lamin A expression varies in healthy cuff cells and in those with different-sized tears where various mechanical stresses are present.

Methods

Forty-three patients with rotator cuff tear (RCT) [23M–20F, mean age (SD): 63.5 (6.1)] were enrolled. Tissue samples excised from the most medial point of tear margins were analyzed for lamin A expression by immunohistochemistry. Controls were represented by samples obtained by normal supraspinatus tendons excised from patients submitted to reverse shoulder prosthesis implant [8M–7F, mean age (SD): 67.9 (7.1)]. The intensity of staining was graded, and an H-score was assigned. Statistical analysis was performed.

Results

Our study revealed a moderate intensity of lamin A in the healthy cuff tendons, a higher expression of this protein in the small tears, and a significant decrease of lamin A with increasing tear size (p < 0.0001).

Conclusions

Our study emphasizes the importance of early repair of small RCTs since nuclear stability is maintained, and the cellular function is protected by lamin A overexpression. High re-tear of massive cuff repair could be due to cellular apoptosis and nuclear modifications induced by lamin A lack.

Level of evidence

III

Low serum vitamin B12 levels are associated with degenerative rotator cuff tear

BACKGROUND

Vitamin B₁₂ (Vit B₁₂) deficiency results in elevated homocysteine levels and interference with collagen cross-linking, which may affect tendon integrity. The purpose of this study was to investigate whether serum Vit B₁₂ levels were correlated with degenerative rotator cuff (RC) tear.

METHODS

Eighty-seven consecutive patients with or without degenerative RC tear were enrolled as study participants. Possible risk factors (age, sex, medical history, bone mineral density, and serum chemistries including glucose, magnesium, calcium, phosphorus, zinc, homocysteine, Vitamin D, Vit B₁₂, homocysteine, and folate) were assessed. Significant variables were selected based on the results of univariate analyses, and a logistic regression model (backward elimination) was constructed to predict the presence of degenerative RC tear.

RESULTS

In the univariate analysis, the group of patients with degenerative RC tear had a mean concentration of 528.4 pg/mL Vit B₁₂, which was significantly lower than the healthy control group (627.1 pg/mL). Logistic regression analysis using Vit B₁₂ as an independent variable revealed that Vit B₁₂ concentrations were significantly correlated with degenerative RC tear (p = 0.044). However, Vit B₁₂ levels were not associated with tear size.

CONCLUSION

Low serum levels of Vit B₁₂ were independently related to degenerative RC tear. Further investigations are warranted to determine if Vit B₁₂ supplementation can decrease the risk of this condition.

Personalized, Predictive, Participatory, Precision, and Preventive (P5) Medicine in Rotator Cuff Tears

Rotator cuff (RC) disease is a common musculoskeletal disorder of the shoulder entailing pain, with reduced functionality and quality of life. The main objective of this study was to present a perspective of the current scientific evidence about personalized, predictive, participatory, precision, and preventive approaches in the management of RC diseases. The personalized, predictive, participatory, precision and preventive (P5) medicine model is an interdisciplinary and multidisciplinary approach that will provide researchers and clinicians with a comprehensive patrimony of knowledge in the management of RC diseases. The ability to define genetic predispositions in conjunction with the evaluation of lifestyle and environmental factors may boost the tailoring of diagnosis and therapy in patients suffering from RC diseases.

Polymorphisms and alterations in gene expression associated with rotator cuff tear and healing following surgical repair: a systematic review

BACKGROUND

Rotator cuff tears (RCTs) are a common cause of shoulder disability, yet both conservative and surgical treatment strategies can lead to poor results in some patient populations. Enhanced understanding of the genetic processes associated with RCTs can assist in the development of more effective management options and help predict individual responses to surgical treatment. This systematic review analyzes the current literature on the genetic footprint associated with RCTs and interprets these findings to enhance the current understanding of RCT pathogenesis, potential treatment regimens, and prognostic biomarkers of outcomes after surgical repair.

METHODS

A systematic search of the Embase, PubMed, and Web of Science electronic databases was performed. Medical Subject Headings (MeSH) and Emtree index terms were formulated from the concept terms "rotator cuff tear," "genetics," and "human," and synonyms of these concepts were applied to the Web of Science search. Articles were screened against predefined inclusion and exclusion criteria. Eligible studies compared gene expression patterns and genetic polymorphisms between cases (with RCTs) and controls (without RCTs). Quality assessment was performed with studies being rated as high, moderate, or poor quality. A modified best-evidence synthesis was applied, and studies were determined to be of strong, moderate, or limited evidence.

RESULTS

The search identified 259 articles. Of these studies, 26 were eligible for review. Two studies were considered poor quality; 15 studies, moderate quality; and 9 studies, high quality. Analysis of these articles found that RCTs were associated with alterations in genes that code for the extracellular matrix, cell apoptosis, immune and inflammatory responses, and growth factor pathways. In particular, there was strong evidence of a significant association between RCTs and the genes MMP3, TNC, and ESRRB. Strong evidence of an association between BMP5 upregulation and successful healing after surgical repair was also found.

CONCLUSION

This review provides strong evidence of an genetic association with RCTs. The genotype and gene expression patterns detailed within this review can assist in deciphering the biological mechanisms resulting in RCTs, as well as predicting an individual's response to surgical repair. Future research could investigate whether manipulating these genes-or their associated signaling pathways-could assist in RCT healing and whether genetic biomarkers could be used clinically to predict patient outcomes after surgical repair of RCTs.

SAP30BP gene is associated with the susceptibility of rotator cuff tear: a case-control study based on Han Chinese population

Background

Multiple studies have indicated that genetic components contribute significantly to the risk of rotator cuff tears. Previous studies have suggested that the SAP30BP gene may play an essential role in the development of rotator cuff tears. The aim of this study was to evaluate the potential association of the SAP30BP gene with the susceptibility to rotator cuff tears in a Han Chinese population.

Methods

A total of 394 patients with rotator cuff tears and 998 healthy controls were included in the study. Twelve tag single nucleotide polymorphisms (SNPs) located in the region of the SAP30BP gene were selected for genotyping. Genetic association analyses were performed using χ² tests for each SNP. Significant associations were searched in the GTEx database for their functional consequences.

Results

SNP rs820218 was significantly associated with rotator cuff tears (χ² = 9.49, P = 0.0021, OR [95% CI] = 0.67 [0.52–0.87]). In addition, SNP rs820218 was found to be significantly associated with the gene expression level of SAP30BP in whole blood (NES = 0.12, P = 1.00 × 10⁻⁶).

Conclusion

Our study has shown that the genetic polymorphism of SAP30BP contributes to the risk of rotator cuff tears in Chinese Han people. Individuals with the A allele for SNP rs820218 were less susceptible to developing rotator cuff tears.

Artificial intelligence: A tool for sports trauma prediction

Injuries exert an enormous impact on athletes and teams. This is seen especially in professional soccer, with a marked negative impact on team performance and considerable costs of rehabilitation for players. Existing studies provide some preliminary understanding of which factors are mostly associated with injury risk, but scientific systematic evaluation of the potential of statistical models in forecasting injuries is still missing. Some factors raise the risk of a sport injury, but there are also elements that predispose athletes to sports injuries. The biological mechanisms involved in non-contact musculoskeletal soft tissue injuries are poorly understood. Genetic risk factors may be associated with susceptibility to injuries, and may exert marked influence on recovery times. Athletes are complex systems, and depend on internal and external factors to attain and maintain stability of their health and their performance. Organisms, participants or traits within a dynamic system adapt and change when factors within that system change. Scientists routinely predict risk in a variety of dynamic systems, including weather, political forecasting and projecting traffic fatalities and the last years have started the use of predictive models in the human health industry. We propose that the use of artificial intelligence may well help in assessing risk and help to predict the occurrence of sport injuries.

Family Predisposition for Rotator Cuff Tear and Other Tendinopathies - A Case-Control Study

Objective  To evaluate the prevalence of family history of rotator cuff tear and the presence of tendinopathy in other joints in patients with rotator cuff tears and to compare them with paired controls. To estimate the odds ratio for rotator cuff tear for these two risk factors. Methods  We performed a case-control study comparing patients submitted to treatment for rotator cuff tear with asymptomatic controls. All cases and controls were evaluated by imaging exams and matched by age (±2 years) and gender. We conducted an interview using a standardized questionnaire, and collected data on various risk factors. Results  We evaluated 144 patients, 72 per group. Patients with rotator cuff tears reported a higher number of consanguineous relatives who underwent treatment for the same disease and tendon injuries in other joints compared to the controls ( p  = 0.005 and p  = 0.045 respectively). Individuals with a family history of treatment for rotator cuff tear or with tendinopathies in other joints were more likely to present a rotator cuff tear, with odds ratios of 3.3 (95% confidence interval [95%CI] = 1.4-7.7) and 2.7 (95%CI = 1.1-6.9) respectively. Conclusions  Patients with rotator cuff tear have a higher prevalence of family members with the same disease and tendinopathies or tendon injuries in other joints. The presence of consanguineous relatives with treatment for rotator cuff and tendinopathies in other joints are risk factors for the presence of rotator cuff tears.

Cost-Effectiveness of Supervised versus Unsupervised Rehabilitation for Rotator-Cuff Repair: Systematic Review and Meta-Analysis

Background: The objective of the present study was to compare the efficacy between supervised and unsupervised rehabilitation after rotator-cuff (RC) repair in terms of clinical outcomes, visual-analog-scale (VAS) score, range of motion (ROM), and risk of retear. Material: a comprehensive search of Pubmed, CINAHL, Cochrane, EMBASE, Ovid, and Google Scholar databases through a combination of the following keywords with logical Boolean operators: “informed”, “uninformed”, “unsupervised”, “supervised”, “rehabilitation”, “physical therapy”, “physical therapies”, “postoperative period”, “physical-therapy techniques”, “physical-therapy technique”, “exercise”, “exercise therapy”, “rotator cuff”, “rotator-cuff tear”, and “rotator-cuff repair”. For each article included in the study, the following data were extracted: authors, year, study design, sample size and demographic features, RC tear characteristics, clinical outcomes, ROM, VAS score, retear rate, and time of follow-up. Meta-analysis was performed in terms of VAS score. Results: Four randomized control trials with 132 patients were included. One study demonstrated significant improvement in VAS, active ROM, and the activity of the muscle’s motor units at stop and during maximal effort in supervised patients. Another one showed lower retear rates in the supervised group. The remaining two randomized controlled trials did not reveal any significant differences between supervised and unsupervised rehabilitation in terms of clinical outcomes. Moreover, higher costs were described for supervised rehabilitation. The VAS was not significantly different in the two groups (9.9 compared with 8.25, p = 0.23). Conclusions: although several publications address the problem of RC lacerations, there is a paucity of evidence in the literature regarding the effectiveness of supervised and unsupervised rehabilitation protocols. This systematic review and meta-analysis showed no significant differences between the two types of rehabilitation in terms of VAS scores, while outlining the pros and cons of each protocol.

Genetic factors in rotator cuff pathology: potential influence of col 5A1 polymorphism in outcomes of rotator cuff repair

Background

Investigations in genetics have provided valuable information about the correlation between gene variants and tendinopathy. Single Nucleotide Polymorphisms of COL5A1 gene are reported to be involved in Achilles tendinopathy, chronic degenerative tendon changes at the elbow, and other tendinopathies. The influence of Single Nucleotide Polymorphisms of COL5A1 was previously analyzed in rotator cuff disease with confounding results. Moreover, the rs12722 polymorphism in COL5A1 gene has been implicated in the aetiology of musculoskeletal soft tissue injuries in several association studies. This study aims to analyse the possible influence of rs12722 polymorphism in COL5A1 in the outcomes of rotator cuff repair.

Methods

Seventy-nine patients were included in the study. DNA was extracted from 1.2 ml of venous blood and genotyped for COL5A1 SNPs rs12722. Rotator cuff muscle strength and range of motion (ROM) in anterior elevation, external and internal rotation of the shoulder were evaluated.

Results

Patients presenting COL5A1 SNP rs12722 CC showed a ROM of passive external rotation statistically significantly higher compared to patients with CT genotype and TT genotype.

Conclusions

COL5A1 SNP rs12722 may influence the functional outcomes of RCRs, even though further studies are required to confirm these preliminary results.

Physical therapy and precision rehabilitation in shoulder rotator cuff disease

PURPOSE

To describe the main features of the rehabilitation protocols for RC disease based on the phases of tendon healing and to investigate about the use of wearable devices as monitoring systems.

METHODS

We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL, and EMBASE databases using various combination of the keywords "rotator cuff," "rotator cuff tear," "rehabilitation protocol," "accelerated," "conservative," "stiffness," "exercises," and "wearable devices." All articles concerning precision orthopaedic rehabilitation therapy in rotator cuff disease were retrieved.

RESULTS

To date, rehabilitation protocols are not comparable due to wide heterogeneity of RC diseases. Wearable technologies are becoming a revolutionary tool for movement and posture monitoring.

CONCLUSION

Rehabilitation protocols for RC disease should be tailored on the basis of the different phases of tendon healing. Wearable devices hold the promise to offer a new outlook for long-term follow-up during the postoperative period providing information to the clinician about patient's status.

Association of Superoxide-Induced Oxidative Stress With Rotator Cuff Tears in Human Patients

Rotator cuff degeneration is one of the factors contributing to rotator cuff tears. Oxidative stress is involved in tendon degeneration, and superoxide-induced oxidative stress plays a pathological role in regulating the balance between oxidation and reduction. The role of oxidative stress in rotator cuff tears, however, is unclear. This study, therefore, aimed to investigate the contribution of superoxide-induced oxidative stress to rotator cuff tears. Seventy patients were recruited and divided into two groups: patients with (Ruptured group) and those without (Unruptured group) a rotator cuff tear. Specimens from both groups were collected during surgery. Degeneration morphology was classified according to the degeneration score. Superoxide-induced oxidative stress was assessed according to dihydroethidium (DHE) relative fluorescence intensity, capacity for antioxidation according to superoxide dismutase (SOD) activity, and the balance between oxidation and reduction based on the redox ratio. Data were compared between groups. Correlations between the degeneration score and the oxidative stress factors were calculated. Degeneration score and DHE relative fluorescence intensity were significantly higher in the Ruptured than the Unruptured group. The SOD activity was not significantly different between groups. Degeneration score was positively correlated with both DHE relative fluorescence intensity and SOD activity. Thus, superoxide-induced oxidative stress and tendon degeneration were greater in rotator cuff tear tissues than in those with no tear, suggesting that oxidative imbalance may be involved in degenerative rotator cuff tears. Clinical Relevance: Understanding the mechanisms of superoxide-induced oxidative stress may lead to targeted tissue therapy for degenerative rotator cuff tears. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:212-218, 2020.

Epidemiology of rotator cuff surgery in Italy: regional variation in access to health care. Results from a 14-year nationwide registry

PURPOSE

Rotator cuff (RC) disease is frequent and represents a common source of shoulder pain. The aim of this study is to analyse geographical differences in RC surgeries from 2001 to 2014 in Italy, a country with universal and free health care for its population.

METHODS

An analysis of the Italian National Hospital Discharge records from 2001 to 2014 was performed. These data are anonymous and include patient's age, sex, domicile, region of hospitalization, length of the hospitalization and type of reimbursement (public or private). National and regional population data were obtained from the National Institute for Statistics (ISTAT) for each year.

RESULTS

During the 14-year study period, 390,001 RC repairs were performed in Italy, which represented a mean incidence of 62.1 RC procedures for every 100,000 Italian inhabitants. Nevertheless, the incidence was very different if every single regional population is considered individually. Lombardy resulted to have the highest number of surgeries during the 14-year study period, with 27.95% (108,954) of the total national procedures performed in the 2001-2014 time span. More than half the surgeries (52.00%) were performed in only 3 regions of the northern part of Italy.

CONCLUSIONS

This study shows the existence of geographical disparities in access to RC surgery and patients' necessity to migrate among regions in order to obtain it. Southern regions of Italy are characterized by a lower number of surgeries compared to the northern part of Italy.

Os Acromiale: Reviews and Current Perspectives

Os acromiale is a developmental defect which results from the lack of an osseous union between the ossification centers of the acromion, leading to the fibrocartilaginous tissue connection. The prevalence of os acromiale is 1% to 15%, and is quite common in the African American population. Os acromiale in adults is easily diagnosed by symptoms and X-ray, particularly on the axillary view; however, the differential diagnosis of adolescents may require MRI or SPECT-CT. Generally, nonoperative therapy for symptomatic os acromiale should be started, including physiotherapy, nonsteroidal anti-inflammatory drugs, and injections. Surgical treatment is indicated after failed conservative treatment. In symptomatic patients with fixable acromiale, the tension band technique should be used to make the anterior aspect of the acromion elevated from the humerus head. In patients with small fragments which are unsuitable for reattachment, excision might be the best therapeutic option and lead to good outcomes. Whether using internal fixation or resection, the arthroscopic technique results in a better outcome and fewer complications, especially in older patients or athletes with overhead movement, because of the high incidence of shoulder impingement or rotator cuff tears which can be treated concurrently.

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

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

Gene Expression Patterns Analysis in the Supraspinatus Muscle after a Rotator Cuff Tear in a Mouse Model

Rotator cuff tear is a muscle-tendinous injury representative of various musculoskeletal disorders. In general, rotator cuff tear occurs in the tendon, but it causes unloading of the muscle resulting in muscle degeneration including fatty infiltration. These muscle degenerations lead to muscle weakness, pain, and loss of shoulder function and are well known as important factors for poor functional outcome after rotator cuff repair. Given that rotator cuff tear in various animal species results in similar pathological changes seen in humans, the animal model can be considered a good approach to understand the many aspects of the molecular changes in injured muscle. To comprehensively analyze changes in gene expression with time following a rotator cuff tear, we established a rotator cuff tear in mouse supraspinatus tendon of shoulder. At weeks 1 and 4 after the tear, the injured muscles were harvested for RNA isolation, and microarray analysis was performed. Expression patterns of genes belonging to 10 muscle physiology-related categories, including aging, apoptosis, atrophy, and fatty acid transport, were analyzed and further validated using real-time PCR. A total of 39,429 genes were analyzed, and significant changes in expression were observed for 12,178 genes at 1 week and 2,370 genes at 4 weeks after the tear. From the list of top 10 significantly up- and downregulated genes at the 2 time periods and the network evaluation of relevant genes according to the 10 categories, several important genes in each category were observed. In this study, we found that various genes are significantly altered after rotator cuff tear, and these genes may play key roles in controlling muscle degeneration after a rotator cuff tear.

Genetics of rotator cuff tears: no association of col5a1 gene in a case-control study

Background

The incidence of RC tears increases with aging, affecting approximately 30 to 50% of individuals older than 50 years, and more than 50% of individuals older than 80 years. Intrinsic factors (age or gender), extrinsic factors (sports activity or occupation), and biological factors were identified in the onset and progression of RC tears. The attention in the study of aetiology of RC tendinopathy has shifted to the identification of gene variants. Genes encoding for proteins regulating the concentration of pyrophosphate in the extracellular matrix and genes encoding for fibroblastic growth factors, defensin beta 1 and estrogen-related receptor-beta were analyzed. However, only in one study the role of variants of collagen type V alpha 1 (col5a1) gene in RC tears was assessed. The objective of this study was to determine whether a col5a1 DNA sequence variant, rs12722 (C/T) was associated with rotator cuff (RC) tears in a case-control study.

Methods

The study included 93 Caucasian patients undergoing surgery for RC tears and 206 patients with no history and sign of RC disease as evaluated by MRI. Patients were divided into two groups. Group 1 included patients with RC tear diagnosed on clinical and imaging grounds and confirmed at the time of surgery. Group 2 (control group) included patients without history or clinical symptoms of RC disorders and with a MRI negative for RC disease. DNA was obtained from approximately 1.2 ml of venous blood using the MagCore extractor system H16 with a MagCore Genomic DNA Large Volume Whole Blood Kit (RBC Bioscience Corp., Taiwan). All study participants were genotyped for SNPs rs12722.

Results

We first estimated that our study had 92% power at p < 0.05 to detect a genetic effect size of 2.05 in the RT tears (93 individuals) and healthy population (206 individuals) cohorts, assuming a minor allele frequency for col5a1 variant rs12722 of 0.5707 in the Italian population (gnomAD frequency). No significant difference in allele and genotype frequencies was observed between RT tears patients and healthy controls. Similarly, no significant association was seen between the RT tears and healthy controls participants in the combined genotype distributions.

Conclusion

In conclusion, no correlations between the SNP rs12722 of col5a1 gene and RC tears susceptibility was found.

Symptomatic, Unstable Os Acromiale

Management of a persistently symptomatic, unstable os acromiale remains controversial. An unstable os acromiale is an easy diagnosis to miss and should be specifically evaluated for in patients with shoulder pain and a high degree of clinical suspicion. Surgical options include open or arthroscopic excision and open reduction and internal fixation. Open excision of large fragments has had poor results. Arthroscopic treatment is commonly used for small fragments (preacromion), and the technique has also been used in larger fragments (meso-os), but concerns persist over postoperative weakness secondary to shortening of the deltoid lever arm. Open reduction and internal fixation through a transacromial approach has been shown to have predictable union rates but can be complicated by symptomatic implant. Recent biomechanical studies have expanded our understanding of optimal fixation constructs, which may also decrease implant-related issues. Ultimately, the choice of which procedure to use will be dictated by patient factors such as age, activity level, and the nature of rotator cuff pathology. LEVEL OF EVIDENCE:: Level V.

Antioxidant treatment with vitamin C attenuated rotator cuff degeneration caused by oxidative stress in Sod1-deficient mice

Background

Rotator cuff degeneration is 1 of several factors that lead to rotator cuff tears; however, the mechanism of this degeneration remains unclear. We previously reported that deficiency of an antioxidant enzyme, superoxide dismutase 1 (Sod1), in mice induced degeneration in supraspinatus tendon entheses, a model that replicates human rotator cuff degeneration. In this study, we analyzed possible effects of vitamin C (VC), a major antioxidant, on the degenerative changes of supraspinatus entheses in Sod1^−/− mice.

Methods

We administered VC or vehicle, distilled water, for 8 weeks to Sod1^−/− and wild-type male mice beginning at 12 weeks of age (n = 5-8 per group). When mice were 20 weeks of age, we sectioned rotator cuff tissue samples and performed hematoxylin-eosin and toluidine blue staining for quantitative histologic evaluation.

Results

VC administration, compared with vehicle administration, attenuated the histologic changes, including a misaligned 4-layered structure, fragmented tidemark, and toluidine blue staining, in the supraspinatus entheses of Sod1^−/− mice. In the quantitative histologic evaluation, all parameters were significantly decreased in Sod1^−/− mice compared with wild-type mice, except for the number of nonchondrocytes.

Conclusion

We demonstrated that an antioxidant treatment, VC administration, attenuated the rotator cuff degeneration, similar to that observed in humans, that is caused by oxidative stress in Sod1^−/− mice. VC effects included improvements in quantitative histologic parameters and other histologic changes. These results suggest that VC treatment can prevent oxidative stress–induced degeneration of the rotator cuff.

Transtendon repair in partial articular supraspinatus tendon tear

INTRODUCTION

Partial thickness rotator cuff tears (PTRCTs) are common, with an incidence between 17% and 37%, and a high prevalence in throwing athletes. Different surgical procedures are suggested when partial tears involve the articular portion of the rotator cuff, including arthroscopic debridement of the tear, debridement with acromioplasty, tear completion and repair, and lately transtendon repair. This systematic review describes the transtendon repair and examines indications, contraindications, complications and clinical outcome.

SOURCE OF DATA

We identified clinical studies listed in the Pubmed Google Scholar, CINAHL, Cochrane Central and Embase Biomedical databases in English and Italian concerning the clinical outcomes following treatment of partial articular supraspinatus tendon tear using transtendon surgical repair.

AREAS OF AGREEMENT

Eighteen studies fulfilled our inclusion criteria. All were published between 2005 and 2016, three were retrospective, and 15 prospective. The total number of patients was 507 with a mean age of 50.8 years.

AREAS OF CONTROVERSY

Tear completion and repair and transtendon repair alone produce similar results.

GROWING POINTS

Transtendon surgical repair allows to obtain good-excellent results in the treatment of partial articular supraspinatus tendon tears.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to produce clear guidelines in the treatment of partial articular supraspinatus tendon tears.

LEVEL OF EVIDENCE

IV.

Matrix Metalloproteases 1 and 3 Promoter Gene Polymorphism Is Associated With Rotator Cuff Tear

BACKGROUND

Studies suggest that the collagen degeneration and disordered arrangement of collagen fibers in rotator cuff tears are associated with an increase in activity of matrix metalloproteases 1 and 3 (MMP-1 and MMP-3), and that MMP activity may be in part genetically mediated. The degree to which this might be clinically relevant in patients with rotator cuff tears has not been well characterized.

QUESTIONS/PURPOSES

(1) Is genetic polymorphism of MMP-1 and MMP-3 associated with rotator cuff tears? (2) Are there haplotypes of MMP-1 and MMP-3 correlated with rotator cuff tears? (3) Compared with control subjects, do patients with rotator cuff tears have a higher proportion of relatives with the same disease?

METHODS

We evaluated 64 patients with full-thickness rotator cuff tears and 64 asymptomatic control subjects. Patients younger 65 years, with nontraumatic tears, were included. The tear or integrity of the rotator cuff tear was evaluated by MRI or ultrasonography in all individuals. The patients and control subjects were paired by age. MMP-1 and MMP-3 genotypes were determined using the PCR-restriction fragment length polymorphism assays.

RESULTS

Genetic polymorphisms in MMP-1 and MMP-3 are associated with rotator cuff tear, in which individuals with rotator cuff tears have associated genotypes 1G/2G (patients, 32 of 64 [50%], control subjects, 16 of 64 [25%]; odds ratio [OR], 4.8; 95% CI, 2.1-11.0; p < 0.001) and 2G/2G were at great risk (patients, 15 of 64 [23%], control subjects, seven of 64 [11%]; OR, 5.2; 95% CI,1.8-14.9; p < 0.001), and patients with rotator cuff tears were associated with a higher proportion of 2G allele distribution (62 of 128 [48%] versus 30 of 128 [23%]; p < 0.001). Patients with the 5A/5A genotype are at greater risk of rotator cuff tear (patients, 15 of 64 [23%]; control subjects, four of 64 [6%]; OR, 5.5; 95% CI, 1.4-20.9; p = 0.021), and there was higher 5A allele distribution in patients with rotator cuff tears (patients, 68 of 128 [53%]; control subjects, 52 of 128 [41%]; p = 0.045). Individuals with the haplotype 2G/5A were more likely to have rotator cuff tears develop (patients, 42 of 64 [66%]; control subjects, 17 of 64 [27%]; OR, 5.3; 95% CI, 2.5-11.3; p < 0.001). Patients with rotator cuff tears reported, in higher number, the existence of relatives who previously had treatment for rotator cuff tears (19 of 64 [30%] versus four of 64 [6%]; OR, 6.3; 95% CI, 2.0-19.9; p = 0.001).

CONCLUSIONS

The genetic polymorphism of MMP-1 and MMP-3 is associated with rotator cuff tear. Individuals with haplotype 2G/5A were more susceptible to rotator cuff tears in the population studied.

CLINICAL RELEVANCE

Knowledge of the genetic markers related to rotator cuff tears can enable identification of susceptible individuals and increase understanding of the pathogenesis of tendon degeneration.

Apoptosis and rotator cuff tears: scientific evidence from basic science to clinical findings

INTRODUCTION

Excessive apoptosis has been hypothesized as possible cause of tendinopathy and tear in the tendons of the rotator cuff (RC). Different mechanisms and molecules play a key role in cell regulation. Biological interventions can affect the process of apoptosis to control the tendinopathy process, and may be useful to design new treatments.

SOURCE OF DATA

We identified basic science, in vitro and in vivo preclinical and clinical studies listed in the Pubmed Google Scholar, CINAHL, Cochrane Central and Embase Biomedical databases in English, Spanish, Italian and French concerning the effects of apoptosis on RC tendons.

AREAS OF AGREEMENT

The homeostasis between the apoptotic and inflammatory processes is dynamic and controlled by pro- and anti-apoptotic mechanisms and signals, with variable balance in different areas of the RC tendons in human specimens.

AREAS OF CONTROVERSY

Apoptosis can be identified along the whole tendon, not only in the area of the lesion. Therefore, it is not necessary to undertake wide debridement of the torn edges of the tendon when undertaking a repair.

GROWING POINTS

The identification of the various factors that control apoptosis and its mechanisms can help to design new treatments and exert positive effects in the recovery from tendon tears.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to produce clear guidelines to determine how to balance the apoptosis process to reduce the failed healing response found in non-traumatic RC tears.

Shoulder Synovial Fluid Lipoprotein Levels and Their Relationship to the Rotator Cuff

INTRODUCTION

Rotator cuff pathology has been proposed to occur through intrinsic and extrinsic mechanisms. Hyperlipidemia has been proposed as a mechanism of intrinsic rotator cuff pathology. This prospective observational study evaluates serum and synovial lipid profiles in patients with and without rotator cuff tears to further define the relationship of cholesterol and rotator cuff pathology.

METHODS

Patients were prospectively enrolled with intact rotator cuff (37 patients) and rotator cuff tear requiring a repair (40 patients) groups. Exclusion criteria were medication for hypercholesterolemia, smoking, previous ipsilateral shoulder surgery, inflammatory arthritis, or history of shoulder infection. Serum and synovial fluid samples were collected at the time of surgery and analyzed for total cholesterol, HDL, non-HDL, and triglycerides.

RESULTS

There were no significant differences seen in any lipid values between patients with rotator cuff and those without a tear. The calculated ratio of synovial lipids to serum lipids was also not significantly different between the patient groups with and without cuff tears.

DISCUSSION

This study successfully evaluates the correlation between serum and synovial lipid levels in the glenohumeral joint. The ratio of lipid values between the serum and the synovial fluid was similar, thus defining a ratio of lipid levels between the blood and the shoulder joint regardless of the presence of a rotator cuff tear. All lipid values measured were similar in both the serum and synovial fluid between patients with and without cuff tears.

[Controversies in the therapy of rotator cuff tears. Operative or nonoperative treatment, open or arthroscopic repair?]

Rotator cuff tears are a common cause of shoulder pain that may lead to severe impairment of shoulder function with significant limitation of the quality of life. Furthermore, they are associated with high direct and indirect costs.Conservative therapy and various surgical procedures for rotator cuff repair are all possible treatment options. Therefore, the correct treatment for a symptomatic rotator cuff tear is important.The conservative therapy may be considered as an alternative treatment option for a symptomatic rotator cuff tear in patients with small or incomplete tears with no fatty atrophy or tendon retraction, with only slight pain, and in older patients with few functional demands. Surgical treatment is recommended after failed conservative treatment lasting 3-6 months, with the corresponding psychological strain. Moreover, surgical treatment should be considered as a primary treatment option for a symptomatic rotator cuff tear in young patients with high functional demands, patients with a high level of physical strain in their jobs, large tears, and tears where there is already significant muscle atrophy or tendon retraction.Arthroscopic treatment is considered to be the gold standard because of the better cosmetic results and treatment of concomitant pathological conditions, the lower levels of postoperative pain, the potentially lower risk of shoulder stiffness, and more focused adhesiolysis. However, arthroscopy does not improve clinical results. Because of the current financial situation, however, open rotator cuff repair is still a viable alternative.

Effect of Bone Mineral Density on Rotator Cuff Tear: An Osteoporotic Rabbit Model

Introduction

An increased bone mineral density (BMD) in the proximity to tendon insertion can improve rotator cuff repair and healing. However, how a decrease of BMD in the humeral head affects the biomechanical properties of the rotator cuff tendon is still unclear. Previous studies have demonstrated ovariectomy in animals to lead to osteoporosis and decreased BMD, and Teriparatide (PTH) administration to improve BMD and strength of bone. This study aimed to explore the correlation between humeral head BMD and infraspinatus (ISP) tendon insertion strength, and if an increase in bone quantity of the humeral head can improve the strength of the rotator cuff.

Materials and Methods

Eighteen New England white rabbits were divided into the 3 groups: Control, Ovariectomy-Saline (OVX-Saline), and Ovariectomy-PTH (OVX-PTH). The OVX-Saline group and the OVX-PTH were administered daily saline and Teriparatide injections for 8 weeks starting at 17 weeks of OVX. BMD of the humeral head was measured, the ISP tendon failure load was tested and the failure stress was calculated. One specimen from each group was used for histological analysis. Linear regression analysis was used to derive equations for the BMD and failure stress.

Results

Significant differences were observed in the measured humeral head BMD of the Control and OVX-PTH groups compared to the OVX-Saline group (P = 0.0004 and P = 0.0024, respectively). No significant difference was found in failure stress among the three groups, but an expected trend with the control group and OVX-PTH group presenting higher failure strength compared to the OVX-Saline group. BMD at the humeral head showed a positive linear correlation with stress (r² = 0.54). Histology results showed the superiority in OVX-PTH group ISP enthesis compared to the OVX-Saline group.

Conclusion

Bone loss of the humeral head leads to decreased tendon/bone insertion strength of the infraspinatus tendon enthesis. Teriparatide administration can increase bone density of the humeral head and may improve the mechanical properties of the infraspinatus tendon enthesis.

Evolution of the human hip. Part 2: muscling the double extension

Part 1 of this article outlined the extensive osseous adaptations around the hip that occurred in the development of a habitual bipedal gait in modern humans. The shortest summary of these osseous changes is 'double extension', i.e. extension of both the hip joint and the lumbar spine. Not surprisingly, these osseous changes went hand in hand with major muscular changes. The primary changes that accompanied the double extension were changes in relative muscle volume for the quadriceps, gluteus maximus and hamstrings, changes in moment arms for the iliopsoas, gluteus maximus and hamstrings, a change in function for the gluteus medius and minimus, while the functional anatomy of the adductors and hip rotators changed only slightly. The effect of these osseous and muscular changes was improved energy efficiency of human bipedal walking and (long distance) running. However, this occurred at the expense of maximum power, characteristic for activities such as tree climbing (in the apes), but equally so for sprinting. Recognizing these changes and their consequences may help us better understand and treat soft-tissue disorders around the hip.

Contribution of oxidative stress to the degeneration of rotator cuff entheses

BACKGROUND

Rotator cuff degeneration is one of the multiple factors that lead to rotator cuff tears; however, the precise mechanism of such degeneration still remains unclear. In this study, we investigated the supraspinatus tendon enthesis to clarify the link between rotator cuff degeneration and oxidative stress in antioxidant enzyme superoxide dismutase 1 (Sod1)-deficient mice (Sod1(-/-)).

METHODS

The supraspinatus tendon and humeral head were isolated and fixed to prepare histologic sections from wild-type and Sod1(-/-) male mice at 20 weeks of age. Hematoxylin-eosin staining was performed to assess the histomorphologic structure. To investigate the collagen fibers, we examined spatially aligned collagen fibers using a polarizing microscope and assessed the amount of collagen using immunohistochemical staining. To analyze the tissue elasticity, we measured the tissue acoustic properties using scanning acoustic microscopy.

RESULTS

The Sod1(-/-) mice showed histologic changes, such as a misaligned 4-layered structure and fragmented tidemark, in the enthesis. Sod1 loss also decreased the amount of brightly diffracted light and type I collagen, indicating collagen downregulation. The scanning acoustic microscopy analysis showed that the speed and attenuation of sound were increased in the nonmineralized fibrocartilage of the Sod1(-/-) mice, suggesting decreased mechanical properties in the supraspinatus enthesis.

CONCLUSION

Sod1 deficiency-induced degeneration is associated with impaired elasticity in the supraspinatus tendon enthesis, recapitulating human rotator cuff degeneration. These results suggest that intracellular oxidative stress contributes to the degeneration of rotator cuff entheses.

Role of serum fibrinogen levels in patients with rotator cuff tears

Although rotator cuff (RC) tendinopathy is a frequent pathology of the shoulder, the real understanding of its aetiopathogenesis is still unclear. Several studies showed that RC tendinopathy is more frequent in patients with hyperglycemia, diabetes, obesity, or metabolic syndrome. This paper aims to evaluate the serum concentration of fibrinogen in patients with RC tears. Metabolic disorders have been related to high concentration of serum fibrinogen and the activity of fibrinogen has been proven to be crucial in the development of microvascular damage. Thus, it may produce progression of RC degeneration by reducing the vascular supply of tendons. We report the results of a cross-sectional frequency-matched case-control study comparing the serum concentration of fibrinogen of patients with RC tears with that of a control group of patients without history of RC tears who underwent arthroscopic meniscectomy. We choose to enrol in the control group patients with pathology of the lower limb with a likely mechanic, not metabolic, cause, different from tendon pathology. We found no statistically significant differences in serum concentration of fibrinogen when comparing patients with RC tears and patients who underwent arthroscopic meniscectomy (P = 0.5). Further studies are necessary to clarify the role of fibrinogen in RC disease.

Instruments to assess patients with rotator cuff pathology: a systematic review of measurement properties

PURPOSE

The aims of this study were to obtain an overview of the methodological quality of studies on the measurement properties of rotator cuff questionnaires and to describe how well various aspects of the design and statistical analyses of studies on measurement properties are performed.

METHODS

A systematic review of published studies on the measurement properties of rotator cuff questionnaires was performed. Two investigators independently rated the quality of the studies using the Consensus-based Standards for the selection of health Measurement Instruments checklist. This checklist was developed in an international Delphi consensus study.

RESULTS

Sixteen studies were included, in which two measurement instruments were evaluated, namely the Western Ontario Rotator Cuff Index and the Rotator Cuff Quality-of-Life Measure. The methodological quality of the included studies was adequate on some properties (construct validity, reliability, responsiveness, internal consistency, and translation) but need to be improved on other aspects. The most important methodological aspects that need to be developed are as follows: measurement error, content validity, structural validity, cross-cultural validity, criterion validity, and interpretability.

CONCLUSION

Considering the importance of adequate measurement properties, it is concluded that, in the field of rotator cuff pathology, there is room for improvement in the methodological quality of studies measurement properties.

LEVEL OF EVIDENCE

II.