The morphological and immunocytochemical features of impingement syndrome and partial-thickness rotator-cuff tear in relation to outcome after subacromial decompression

The Usefulness of Serological Inflammatory Markers in Patients with Rotator Cuff Disease—A Systematic Review

Background and Objectives: Rotator cuff disease (RCD) is a prominent musculoskeletal pain condition that spans a variety of pathologies. The etiology and precise diagnostic criteria of this condition remain unclear. The current practice of investigating the biochemical status of RCD is by conducting biopsy studies but their invasiveness is a major limitation. Recent biochemical studies on RCD demonstrate the potential application of serological tests for evaluating the disease which may benefit future clinical applications and research. This systematic review is to summarize the results of available studies on serological biochemical investigations in patients with RCD. Methods: An electronic search on databases PubMed and Virtual Health Library was conducted from inception to 1 September 2021. The inclusion criteria were case-control, cross-sectional, and cohort studies with serological biochemical investigations on humans with RCD. Methodological quality was assessed using the Study Quality Assessment Tool for Observational Cohort and Cross-sectional studies from the National Heart, Lung, and Blood Institute. Results: A total of 6008 records were found in the databases; of these, 163 full-text studies were checked for inclusion and exclusion criteria. Nine eligible studies involving 984 subjects with RCD emerged from this systematic review. The quality of the studies found ranged from poor to moderate. In summarizing all the studies, several fatty acids, nonprotein nitrogen, interleukin-1 β, interleukin-8, and vascular endothelial growth factor were found to be significantly higher in blood samples of patients with RCD than with control group patients, while Omega-3 Intex, vitamin B12, vitamin D, phosphorus, interleukin-10, and angiogenin were observed to be significantly lower. Conclusions: This is the first systematic review to summarize current serological studies in patients with RCD. Results of the studies reflect several systemic physiological changes in patients with RCD, which may prove helpful to better understand the complex pathology of RCD. In addition, the results also indicate the possibility of using serological tests in order to evaluate RCD; however, further longitudinal studies are required.

Subacromial Bursa: A Neglected Tissue Is Gaining More and More Attention in Clinical and Experimental Research

The subacromial bursa has long been demolded as friction-reducing tissue, which is often linked to shoulder pain and, therefore, partially removed during shoulder surgery. Currently, the discovery of the stem cell potential of resident bursa-derived cells shed a new light on the subacromial bursa. In the meanwhile, this neglected tissue is gaining more attention as to how it can augment the regenerative properties of adjacent tissues such as rotator cuff tendons. Specifically, the tight fibrovascular network, a high growth factor content, and the large progenitor potential of bursa-derived cells could complement the deficits that a nearby rotator cuff injury might experience due to the fact of its low endogenous regeneration potential. This review deals with the question of whether bursal inflammation is only a pain generator or could also be an initiator of healing. Furthermore, several experimental models highlight potential therapeutic targets to overcome bursal inflammation and, thus, pain. More evidence is needed to fully elucidate a direct interplay between subacromial bursa and rotator cuff tendons. Increasing attention to tendon repair will help to guide future research and answer open questions such that novel treatment strategies could harvest the subacromial bursa's potential to support healing of nearby rotator cuff injuries.

Bursa-Derived Cells Show a Distinct Mechano-Response to Physiological and Pathological Loading in vitro

The mechano-response of highly loaded tissues such as bones or tendons is well investigated, but knowledge regarding the mechano-responsiveness of adjacent tissues such as the subacromial bursa is missing. For a better understanding of the physiological role of the bursa as a friction-reducing structure in the joint, the study aimed to analyze whether and how bursa-derived cells respond to physiological and pathological mechanical loading. This might help to overcome some of the controversies in the field regarding the role of the bursa in the development and healing of shoulder pathologies. Cells of six donors seeded on collagen-coated silicon dishes were stimulated over 3 days for 1 or 4 h with 1, 5, or 10% strain. Orientation of the actin cytoskeleton, YAP nuclear translocation, and activation of non-muscle myosin II (NMM-II) were evaluated for 4 h stimulations to get a deeper insight into mechano-transduction processes. To investigate the potential of bursa-derived cells to adapt their matrix formation and remodeling according to mechanical loading, outcome measures included cell viability, gene expression of extracellular matrix and remodeling markers, and protein secretions. The orientation angle of the actin cytoskeleton increased toward a more perpendicular direction with increased loading and lowest variations for the 5% loading group. With 10% tension load, cells were visibly stressed, indicated by loss in actin density and slightly reduced cell viability. A significantly increased YAP nuclear translocation occurred for the 1% loading group with a similar trend for the 5% group. NMM-II activation was weak for all stimulation conditions. On the gene expression level, only the expression of TIMP2 was down-regulated in the 1 h group compared to control. On the protein level, collagen type I and MMP2 increased with higher/longer straining, respectively, whereas TIMP1 secretion was reduced, resulting in an MMP/TIMP imbalance. In conclusion, this study documents for the first time a clear mechano-responsiveness in bursa-derived cells with activation of mechano-transduction pathways and thus hint to a physiological function of mechanical loading in bursa-derived cells. This study represents the basis for further investigations, which might lead to improved treatment options of subacromial bursa-related pathologies in the future.

Acromioplasty in the surgical operations of partial-thickness rotator cuff tears: A comprehensive review

The partial-thickness rotator cuff tears (PTRCTs) are known as a prevalent pathology, which cause inability mostly in athletes. So far, a number of treatments have been suggested depending on patient characteristics and size and location of the tears. Surgical repair in rotator cuff tears that include 50% or more of the tendon thickness is the accepted practice in the following failure of nonoperative treatment. In the surgical procedure, acromioplasty is known as a long-established component and used to modify the detrimental acromion morphology, which accounts for rotator cuff tearing. A range of trials has been reported that compare the results of surgical procedure with and without acromioplasty in patients undergoing rotator cuff repairs. According to the findings of 15 studies including ~1,500 patients, with mean age 60 years (range 5-80 years) and mean follow-up of 22 months (range 13-26 months) found by searching on Cochrane Register of Controlled Trials databases, Excerpta Medica/Embase, and Medline/PubMed, we revealed that acromioplasty cannot present an impressive effect on patient outcome scores at intermediate and short-term follow-ups. In fact, despite the theoretic advantages of acromioplasty in the setting of PTRCTs, it has reported little or no efficacy on outcomes of postoperative patients.

Effectiveness of Biologic Factors in Shoulder Disorders

Background:

Shoulder pathology can cause significant pain, discomfort, and loss of function that all interfere with activities of daily living and may lead to poor quality of life. Primary osteoarthritis and rotator cuff diseases with its sequalae are the main culprits. Management of shoulder disorders using biological factors gained an increasing interest over the last years. This interest reveals the need of effective treatments for shoulder degenerative disorders, and highlights the importance of a comprehensive and detailed understanding of the rapidly increasing knowledge in the field.

Methods:

This study will describe most of the available biology-based strategies that have been recently developed, focusing on their effectiveness in animal and clinical studies.

Results:

Data from in vitro work will also be briefly presented; in order to further elucidate newly acquired knowledge regarding mechanisms of tissue degeneration and repair that would probably drive translational work in the next decade. The role of platelet rich-plasma, growth factors, stem cells and other alternative treatments will be described in an evidence-based approach, in an attempt to provide guidelines for their clinical application. Finally, certain challenges that biologic treatments face today will be described as an initiative for future strategies.

Conclusion:

The application of different growth factors and mesenchymal stem cells appears as promising approaches for enhancing biologic repair. However, data from clinical studies are still limited, and future studies need to improve understanding of the repair process in cellular and molecular level and evaluate the effectiveness of biologic factors in the management of shoulder disorders.

Proteomics perspectives in rotator cuff research: a systematic review of gene expression and protein composition in human tendinopathy

BACKGROUND

Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other tendinopathies, and to evaluate perspectives of proteomics--the comprehensive study of protein composition--in tendon research.

MATERIALS AND METHODS

We conducted a systematic search of the literature published between 1 January 1990 and 18 December 2012 in PubMed, Embase, and Web of Science. We included studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue.

RESULTS

We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy. Most of the included studies quantified prespecified mRNA molecules and proteins using polymerase chain reactions and immunoassays, respectively. There was a tendency towards an increase of collagen I (11 of 15 studies) and III (13 of 14), metalloproteinase (MMP)-1 (6 of 12), -9 (7 of 7), -13 (4 of 7), tissue inhibitor of metalloproteinase (TIMP)-1 (4 of 7), and vascular endothelial growth factor (4 of 7), and a decrease in MMP-3 (10 of 12). Fourteen proteomics studies of tendon tissues/cells failed inclusion, mostly because they were conducted in animals or in vitro.

CONCLUSIONS

Based on methods, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although proteomics technologies may be a way to identify protein profiles (including non-prespecified proteins) that characterise specific tendon disorders or stages of tendinopathy. Thus, our results suggested an untapped potential for proteomics in tendon research.

PARot--assessing platelet-rich plasma plus arthroscopic subacromial decompression in the treatment of rotator cuff tendinopathy: study protocol for a randomized controlled trial

Background

Platelet-rich plasma (PRP) is an autologous platelet concentrate. It is prepared by separating the platelet fraction of whole blood from patients and mixing it with an agent to activate the platelets. In a clinical setting, PRP may be reapplied to the patient to improve and hasten the healing of tissue. The therapeutic effect is based on the presence of growth factors stored in the platelets. Current evidence in orthopedics shows that PRP applications can be used to accelerate bone and soft tissue regeneration following tendon injuries and arthroplasty. Outcomes include decreased inflammation, reduced blood loss and post-treatment pain relief. Recent shoulder research indicates there is poor vascularization present in the area around tendinopathies and this possibly prevents full healing capacity post surgery (Am J Sports Med36(6):1171–1178, 2008). Although it is becoming popular in other areas of orthopedics there is little evidence regarding the use of PRP for shoulder pathologies. The application of PRP may help to revascularize the area and consequently promote tendon healing. Such evidence highlights an opportunity to explore the efficacy of PRP use during arthroscopic shoulder surgery for rotator cuff pathologies.

Methods/Design

PARot is a single center, blinded superiority-type randomized controlled trial assessing the clinical outcomes of PRP applications in patients who undergo shoulder surgery for rotator cuff disease. Patients will be randomized to one of the following treatment groups: arthroscopic subacromial decompression surgery or arthroscopic subacromial decompression surgery with application of PRP.

The study will run for 3 years and aims to randomize 40 patients. Recruitment will be for 24 months with final follow-up at 1 year post surgery. The third year will also involve collation and analysis of the data. This study will be funded through the NIHR Biomedical Research Unit at the Oxford University Hospitals NHS Trust.

Trial registration

Current Controlled Trials: ISRCTN10464365

A systematic review of the histological and molecular changes in rotator cuff disease

INTRODUCTION

The pathogenesis of rotator cuff disease (RCD) is complex and not fully understood. This systematic review set out to summarise the histological and molecular changes that occur throughout the spectrum of RCD.

METHODS

We conducted a systematic review of the scientific literature with specific inclusion and exclusion criteria.

RESULTS

A total of 101 studies met the inclusion criteria: 92 studies used human subjects exclusively, seven used animal overuse models, and the remaining two studies involved both humans and an animal overuse model. A total of 58 studies analysed supraspinatus tendon exclusively, 16 analysed subacromial bursal tissue exclusively, while the other studies analysed other tissue or varying combinations of tissue types including joint fluid and muscle. The molecular biomarkers that were altered in RCD included matrix substances, growth factors, enzymes and other proteins including certain neuropeptides.

CONCLUSIONS

The pathogenesis of RCD is being slowly unravelled as a result of the significant recent advances in molecular medicine. Future research aimed at further unlocking these key molecular processes will be pivotal in developing new surgical interventions both in terms of the diagnosis and treatment of RCD.

Evidence that central sensitisation is present in patients with shoulder impingement syndrome and influences the outcome after surgery

Impingement syndrome in the shoulder has generally been considered to be a clinical condition of mechanical origin. However, anomalies exist between the pathology in the subacromial space and the degree of pain experienced. These may be explained by variations in the processing of nociceptive inputs between different patients. We investigated the evidence for augmented pain transmission (central sensitisation) in patients with impingement, and the relationship between pre-operative central sensitisation and the outcomes following arthroscopic subacromial decompression.

We recruited 17 patients with unilateral impingement of the shoulder and 17 age- and gender-matched controls, all of whom underwent quantitative sensory testing to detect thresholds for mechanical stimuli, distinctions between sharp and blunt punctate stimuli, and heat pain. Additionally Oxford shoulder scores to assess pain and function, and PainDETECT questionnaires to identify ‘neuropathic’ and referred symptoms were completed. Patients completed these questionnaires pre-operatively and three months post-operatively.

A significant proportion of patients awaiting subacromial decompression had referred pain radiating down the arm and had significant hyperalgesia to punctate stimulus of the skin compared with controls (unpaired t-test, p < 0.0001). These are felt to represent peripheral manifestations of augmented central pain processing (central sensitisation).

The presence of either hyperalgesia or referred pain pre-operatively resulted in a significantly worse outcome from decompression three months after surgery (unpaired t-test, p = 0.04 and p = 0.005, respectively).

These observations confirm the presence of central sensitisation in a proportion of patients with shoulder pain associated with impingement. Also, if patients had relatively high levels of central sensitisation pre-operatively, as indicated by higher levels of punctate hyperalgesia and/or referred pain, the outcome three months after subacromial decompression was significantly worse.

Multimedia article. The arthroscopic management of partial-thickness rotator cuff tears: a systematic review of the literature

PURPOSE

There is currently limited information available in the orthopaedic surgery literature regarding the appropriate management of symptomatic partial-thickness rotator cuff tears.

METHODS

A systematic search was performed in PubMed, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the Cochrane Central Register of Controlled Trials of all published literature pertaining to the arthroscopic management of partial-thickness rotator cuff tears. Inclusion criteria were all studies that reported clinical outcomes after arthroscopic treatment of both articular-sided and bursal-sided lesions using a validated outcome scoring system and a minimum of 12 months of follow-up. Data abstracted from the selected studies included tear type and location (articular v bursal sided), treatment approach, postoperative rehabilitation protocol, outcome scores, patient satisfaction, and postoperative imaging results.

RESULTS

Sixteen studies met the inclusion criteria and were included for the final analysis. Seven of the studies treated partial-thickness rotator cuff tears with debridement with or without an associated subacromial decompression, 3 performed a takedown and repair, 5 used a transtendon repair technique, and 1 used a transosseous repair method. Among the 16 studies reviewed, excellent postoperative outcomes were reported in 28.7% to 93% of patients treated. In all 12 studies with available preoperative baseline data, treatment resulted in significant improvement in shoulder symptoms and function. For high-grade lesions, the data support arthroscopic takedown and repair, transtendon repairs, and transosseous repairs, with all 3 techniques providing a high percentage of excellent results. Debridement of partial-thickness tears of less than 50% of the tendon's thickness with or without a concomitant acromioplasty also results in good to excellent surgical outcomes; however, a 6.5% to 34.6% incidence of progression to full-thickness tears is present.

CONCLUSIONS

This systematic review of 16 clinical studies showed that significant variation is present in the results obtained after the arthroscopic management of partial-thickness rotator cuff tears. What can be supported by the available data is that tears that involve less than 50% of the tendon can be treated with good results by debridement of the tendon with or without a formal acromioplasty, although subsequent tear progression may occur. When the tear is greater than 50%, surgical intervention focusing on repair has been successful. There is no evidence to suggest a differential in outcome for tear completion and repair versus transtendon repair of these lesions because both methods have been shown to result in favorable outcomes.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Rotator cuff changes in a full thickness tear rat model: verification of the optimal time interval until reconstruction for comparison to the healing process of chronic lesions in humans

BACKGROUND

The aim of the study was to develop a standardized rat model for chronic rotator cuff tears. Therefore, a time point of degenerative changes that shows comparable histological changes to the chronic tendon tears in humans had to be determined. The rat shoulder has already been described as a standardized model for investigation of the healing behavior in acute supraspinatus lesions. Little data exist about the possibility of generating a chronic rotator cuff lesion.

METHODS

We performed a complete detachment of the supraspinatus tendon in 45 Sprague-Dawley rats. After an interval of 3, 6 and 9 weeks (15 rats in each group), the macroscopic and histological changes were analyzed. The histological investigation included atrophy and fatty muscle degeneration, tendon degeneration and the grade of inflammatory changes. For evaluation of tendon degeneration, a modified MOVIN-Score was used. The contralateral shoulder provided as control group.

RESULTS

Macroscopically the defect showed an increasing coverage with scar tissue over time with a complete closure in 73% after 9 weeks. The 3 week group showed the highest rate of persisting defects (80%). The atrophy of the supraspinatus muscle decreased from initial slight atrophy to a nearly normal muscle status in the 9 week group. Fatty infiltration was found in three animals per group regardless of the time interval after detachment. Tendon degeneration (modified MOVIN-Score) showed no significant difference between 3 and 6 weeks (p = 0.93) whereas after 9 weeks a significant increased degeneration was found (p < 0.01). In the early phase (3 and 6 weeks), inflammatory cells could be detected more frequently.

CONCLUSIONS

The results show that a chronic tear of the human rotator cuff can be imitated in the rat model with some exclusion. The rapid self-healing response in the rat and the fatty infiltration of the human muscle are the main differences. However, tendon degeneration, inflammation and muscle atrophy combined with a persisting defect at 3 weeks after detachment are comparable to the chronic tendon tears in humans. This model can serve as a basis for further research in the field of rotator cuff repair for chronic lesions.

Fourier transform infrared spectroscopic analysis of normal and torn rotator-cuff tendons

We have used Fourier transform infrared spectroscopy (FTIR) to characterise the chemical and structural composition of the tendons of the rotator cuff and to identify structural differences among anatomically distinct tears. Such information may help to identify biomarkers of tears and to provide insight into the rates of healing of different sizes of tear. The infrared spectra of 81 partial, small, medium, large and massive tears were measured using FTIR and compared with 11 uninjured control tendons. All the spectra were classified using standard techniques of multivariate analysis.

FTIR readily differentiates between normal and torn tendons, and different sizes of tear. We identified the key discriminating molecules and spectra altered in torn tendons to be carbohydrates/phospholipids (1030 cm−1 to 1200 cm−1), collagen (1300 cm−1 to 1700 cm−1 and 3000 cm−1 to 3350 cm−1) and lipids (2800 cm−1 to 3000 cm−1).

Our study has shown that FTIR spectroscopy can identify tears of the rotator cuff of varying size based upon distinguishable chemical and structural features. The onset of a tear is mainly associated with altered structural arrangements of collagen, with changes in lipids and carbohydrates. The approach described is rapid and has the potential to be used peri-operatively to determine the quality of the tendon and the extent of the disease, thus guiding surgical repair.

Clinical, socio-demographic and radiological predictors of short-term outcome in rotator cuff disease

Background

Shoulder pain is common with rotator cuff disease as the most frequently used clinical diagnosis. There is a wide range of treatment options for this condition, but limited evidence to guide patients and clinicians in the choice of treatment strategy. The purpose of this study was to investigate possible prognostic factors of short-term outcome after corticosteroid injection for rotator cuff disease.

Methods

We performed analyses of data from 104 patients who had participated in a randomized controlled study. Socio-demographic, clinical and radiographic baseline factors were assessed for association with outcome at six-weeks follow-up evaluated by Shoulder Pain and Disability Index (SPADI) and patient perceived outcome. Factors with significant univariate association were entered into multivariate linear and logistic regression analyses.

Results

In the multivariate analyses; a high SPADI score indicating pain and disability at follow-up was associated with decreasing age, male gender, high baseline pain and disability, being on sick-leave, and using regular pain medication. A successful patient perceived outcome was associated with not being on sick-leave, high active abduction, local corticosteroid injection and previous cortisone injections. Structural findings of rotator cuff tendon pathology on MRI and bursal exudation or thickening on ultrasonography did not contribute to the predictive model.

Conclusions

Baseline characteristics were associated with outcome after corticosteroid injection in rotator cuff disease. Sick-leave was the best predictor of poor short-term outcome. Trial registration: Clinical trials NCT00640575