Objectives . The effects of disease progression and common tendinopathy treatments
on the tissue characteristics of human rotator cuff tendons have
not previously been evaluated in detail owing to a lack of suitable
sampling techniques. This study evaluated the structural characteristics
of torn human
We examined macroscopically and microscopically 55 cadaver rotator-cuff tendons attached to their humeral heads to determine the distance between the edge of the articular cartilage and the tendon insertion of the supraspinatus (the width of the sulcus) and the score of regressive changes at the sulcus. In 33 specimens we measured the tensile strength. The width of the sulcus was correlated with the score of regressive changes and with the ultimate tensile strength of the
Differential strain has been proposed to be a causative factor in failure of the
Obesity is associated with poor outcomes and increased risk of failure after rotator cuff (RC) repair surgery. The effect of diet-induced obesity (DIO) on enthesis healing has not been well characterised and whether its effects can be reversed with dietary intervention is unknown. We hypothesised that DIO would result in inferior enthesis healing in a rat model of RC repair and that dietary intervention in the peri-operative period would improve enthesis healing. A total of 78 male Sprague-Dawley rats were divided into three weight-matched groups from weaning and fed either: control diet (CD), high-fat diet (HFD), or HFD until surgery, then CD thereafter (HF-CD). After 12 weeks the left
The rotator cuff tendinopathy is one of the most common shoulder problems leading to full-thickness rotator cuff tendon tear and, eventually, to degenerative arthritis. Recent research on rotator cuff tendon degeneration has focused on its relationship to cell death. The types of cell death known to be associated with rotator cuff tendon degeneration are apoptosis, necrosis, and autophagic cell death. The increased incidence of cell death in degenerative tendon tissue may affect the rates of collagen synthesis and repair, possibly weakening tendon tissue and increasing the risk of tendon rupture. The biomolecular mechanisms of the degenerative changes leading to apoptotic cell death in rotator cuff tenofibroblasts have been identified as oxidative-stress-related cascade mechanisms. Furthermore, apoptosis, necrosis, and autophagic cell death are all known to be mediated by oxidative stress, a condition in which ROS (reactive oxygen species) are overproduced. Lower levels of oxidative stress trigger apoptosis; higher levels mediate necrosis. Although the signaltransduction pathway leading to autophagy has not yet been fully established, ROS are known to be essential to autophagy. A neuronal theory regarding rotator cuff degeneration has been developed from the findings that glutamate, a neural transmitter, is present in increased concentrations in tendon tissues with tendinopathy and that it induces rat
Treatment of massive rotator cuff tears can be challenging. Previous studies with irreparable rotator cuff tears showed good clinical results of tendon healing with the arthroscopic insertion of a protective biodegradable spacer balloon filled with saline solution between the repaired tendon and the acromion [1,2], but so far no scientific evidence has showed how the device alters pressures over the repaired tendon. This biomechanical study investigated the effects of a spacer inserted in the subacromial space on pressures over the repaired rotator cuff tendon in passive motion cycles typical for post-operative rehabilitation routines. Six human cadaveric shoulders were prepared with the humerus cut 15cm below the joint and embedded in a pot, while the scapula fixed at three points on a plate. A rotator cuff tear was simulated and repaired using a suture anchor and a Mason-Allen suture. The specimens were then mounted on a custom-made pneumatic testing rig to induce passive motion cycles of adduction-abduction (90–0°) and flexion-extension (0–40°) with constant glenohumeral and superior loads and tension is exerted on the
The role of inflammatory cells and their products in tendinopathy is not completely understood. Pro-inflammatory cytokines are upregulated after oxidative and other forms of stress. Based on observations that increased cytokine expression has been demonstrated in cyclically-loaded tendon cells we hypothesised that because of their role in oxidative stress and apoptosis, pro-inflammatory cytokines may be present in rodent and human models of tendinopathy. A rat supraspinatus tendinopathy model produced by running overuse was investigated at the genetic level by custom micro-arrays. Additionally, samples of torn
We compared time-dependent changes in the biomechanical properties of single-and double-row repair of a simulated acute tear of the rotator cuff in rabbits to determine the effect of the fixation techniques on the healing process. A tear of the
Critical shoulder angle (CSA), lateral acromial angle (LAA), and acromion index (AI) are common radiologic parameters used to distinguish between patients with rotator cuff tears (RCT) and those with an intact rotator cuff. This study aims to assess the predictive power of these parameters in degenerative RCT. This retrospective study included data from 92 patients who were divided into two groups: the RCT group, which included 47 patients with degenerative full-thickness
Summary Statement. Tendon-bone interface becomes matured with the perforating fiber and the cells striding over the bone area. We suggest that both “perforating fiber” and “cell stride” could play a crucial role in regeneration after rotator cuff repair. Introduction. To obtain a successful outcome after rotator cuff repair, repaired tendon requires to be anchored biologically to the bone. However, it is well known that the histological structure of the repaired tendon-bone insertion is totally different from the normal insertion. This morphological alteration may contribute to biological instability after surgical repair. To address these issues, it is fundamental to clarify the difference of the structure between the normal and the repaired insertion in detail. Surprisingly, few studies on the tendon-bone insertion using electron microscopy has been performed so far, since the insertion area is solid (bone/cartilage) and extremely limited for the analysis. Recently, a new scanning electron microscopical method (FIB/SEM tomography) has been developed, making it possible to analyze the wider area with the higher resolution and reconstruct 3D ultrastructures. The purpose of this study was to analyze the ultrastructure of the repaired supraspinatus tendon-bone insertion in rat using FIB/SEM tomography. Materials and Methods. Adult Sprague-Dawley rats underwent complete cuff tear and subsequent repair of the
The retear of the rotator cuff (RC) repair is a significant problem. Usually it is the effect of poor quality of the tendon. The aim was to evaluate histologically two types of RC reconstruction with scaffold. We have chosen commercially available scaffold polycaprolactone based poly(urethane urea). Rat model of
PEMF is currently approved by the FDA for adjunctive treatment of lumbar/cervical spine fusion and for treatment of long-bone non-unions. Soft tissues are a potential new therapeutic application for PEMF due to pre-clinical studies showing a reduction of inflammatory markers following PEMF exposure. The aim was therefore to investigate the structural/functional effects of PEMFs on tendon-to-bone and tendon-to-tendon healing in a rotator-cuff (RC) and Achilles tendon (AT) repair model, respectively. RC study: Adult male rats (n=280), underwent bi-lateral
Surgical repair of rotator cuff tears have high failure rates (20–70%), often due to a lack of biological healing. Augmenting repairs with extracellular matrix-based scaffolds is a common option for surgeons, although to date, no commercially available product has proven to be effective. In this study, a novel collagen scaffold was assessed for its efficacy in augmenting rotator cuff repair. The collagen scaffold was assessed in vitro for cytocompatability and retention of tenocyte phenotype using alamarBLUE assays, confocal imaging and real-time PCR. Immunogenicity was assessed in vitro by the activation of pre-macrophage cells. In vivo, using a modified rat rotator cuff defect model,
Alarmins- also referred to as damage associated molecular patterns (DAMPS)- are endogenous molecules mobilized in response to tissue damage known to activate the innate immune system and regulate tissue repair and remodelling. The molecular mechanisms that regulate inflammatory and remodelling pathways in tendinopathy are largely unknown therefore identifying early immune effectors is essential to understanding the pathology. S100A8 and S100A9 are low molecular weight calcium binding proteins primarily released by activated phagocytes in an inflammatory setting and also secreted as a heterodimeric complex that exhibits cytokine like functions. Based on our previous investigations we sought evidence of S100A8/A9 expression in human tendinopathy and thereafter, to explore mechanisms whereby S100 proteins may regulate inflammatory mediators and matrix regulation in human tenocytes. Torn
Introduction. Platelet Rich Plasma (PRP) is widely used in clinical praxis. Especially the effects in musculoskeletal repair studies are diverse and an augmentation of healing processes stays questionable. However, diverse cell culture studies reported promising results, which seem not be transferable into the clinical situation. We therefore performed a cell culture study which better reflects the clinical situation: the autologous stimulation of human tendon cells with PRP. Materials and Methods. Human tenocyte-like cells (hTLCs) from 24 donors (12 male/female) with
We report an unusual case of knee disease where calcific tendonitis occurring in both quadriceps and patellar tendon simultaneously in the same knee. A 47 year old female presented to orthopaedics outpatient clinic with acute onset of swelling and knee pain with no history of trauma. She was found to have a moderate effusion of the knee joint with mild tenderness over the mid quadriceps tendon. Active flexion of the knee joint was painful with a range of motion between 0-90 degrees. She is otherwise healthy with no past medical history. Plain radiographs and Magnetic Resonance Imaging (MRI) Scan revealed calcification of both tendons. Calcific tendonitis is classically found in the
The objective was to seek evidence of hypoxia in early human tendinopathy and thereafter, to explore mechanisms whereby tissue hypoxia may regulate apoptosis, inflammatory mediators and matrix regulation in human tenocytes. Fifteen torn
Summary Statement. The peripheral neuronal phenotype is significantly altered in rotator cuff tendinopathy (RCT) with a clear upregulation of the Glutaminergic system being present in disease. Introduction. Shoulder pain is the third most frequent cause of chronic musculoskeletal pain in the community and is usually caused by rotator cuff tendinopathy (RCT). The central and peripheral nervous system play an important role in both tissue homoeostasis and tendon healing. The Glutaminergic system is of key importance in driving the peripheral and central neuronal changes which increase the body's sensitivity to pain (1, 2). No study to date has investigated the role of the glutaminergic system in human RCT. We hypothesised that the peripheral neuronal phenotype would be altered in RCT, and would vary according to disease stage as measured by size of tear. The term ‘peripheral neuronal phenotype’ is used to refer to refer to specific characteristics of the peripheral nervous system, neuronal mediators and the receptors for these mediators in peripheral tissue. Methods. Rotator cuff tendon specimens were obtained from 64 patients undergoing the surgical repair of rotator cuff tears. Control
Platelet-rich fibrin matrix (PRFM) has been proved to enhance tenocyte proliferation but has mixed results when used during rotator cuff repair. The optimal PRFM preparation protocol should be determined before clinical application. To screen the best PRFM to each individual’s tenocytes effectively, small-diameter culture wells should be used to increase variables. The gelling effect of PRFM will occur when small-diameter culture wells are used. A co-culture device should be designed to avoid this effect. Tenocytes harvested during rotator cuff repair and blood from a healthy volunteer were used. Tenocytes were seeded in 96-, 24-, 12-, and six-well plates and co-culture devices. Appropriate volumes of PRFM, according to the surface area of each culture well, were treated with tenocytes for seven days. The co-culture device was designed to avoid the gelling effect that occurred in the small-diameter culture well. Cell proliferation was analyzed by water soluble tetrazolium-1 (WST-1) bioassay.Objectives
Methods
Triamcinolone acetonide (TA) is widely used for the treatment of rotator cuff injury because of its anti-inflammatory properties. However, TA can also produce deleterious effects such as tendon degeneration or rupture. These harmful effects could be prevented by the addition of platelet-rich plasma (PRP), however, the anti-inflammatory and anti-degenerative effects of the combined use of TA and PRP have not yet been made clear. The objective of this study was to determine how the combination of TA and PRP might influence the inflammation and degeneration of the rotator cuff by examining rotator cuff-derived cells induced by interleukin (IL)-1ß. Rotator cuff-derived cells were seeded under inflammatory stimulation conditions (with serum-free medium with 1 ng/ml IL-1ß for three hours), and then cultured in different media: serum-free (control group), serum-free + TA (0.1mg/ml) (TA group), serum-free + 10% PRP (PRP group), and serum-free + TA (0.1mg/ml) + 10% PRP (TA+PRP group). Cell morphology, cell viability, and expression of inflammatory and degenerative mediators were assessed.Objectives
Methods