Aims

Rotator cuff tear (RCT) is the leading cause of shoulder pain, primarily associated with age-related tendon degeneration. This study aimed to elucidate the potential differential gene expressions in tendons across different age groups, and to investigate their roles in tendon degeneration.

We have studied cellular and vascular changes in different stages of full thickness tears of the rotator cuff. We examined biopsies from the supraspinatus tendon in 40 patients with chronic rotator cuff tears who were undergoing surgery and compared them with biopsies from four uninjured subscapularis tendons. Morphological and immunocytochemical methods using monoclonal antibodies directed against leucocytes, macrophages, mast cells, proliferative and vascular markers were used.

Histological changes indicative of repair and inflammation were most evident in small sized rotator cuff tears with increased fibroblast cellularity and intimal hyperplasia, together with increased expression of leucocyte and vascular markers. These reparative and inflammatory changes diminished as the size of the rotator cuff tear increased. Marked oedema and degeneration was seen in large and massive tears, which more often showed chondroid metaplasia and amyloid deposition. There was no association between the age of the patient and the duration of symptoms. In contrast, large and massive tears showed no increase in the number of inflammatory cells and blood vessels.

Small sized rotator cuff tears retained the greatest potential to heal, showing increased fibroblast cellularity, blood vessel proliferation and the presence of a significant inflammatory component. Tissue from large and massive tears is of such a degenerative nature that it may be a significant cause of re-rupture after surgical repair and could make healing improbable in this group.

This study reports the application of a novel method for quantitatively determining differences in the mechanical properties of healthy and torn rotator cuff tissues. In order to overcome problems of stress risers at the grip-tendon interface that can obscure mechanical measurements of small tendons, we conducted our investigation using dynamic shear analysis.

Rotator cuff tendon specimens were obtained from 100 patients during shoulder surgery. They included 82 differently sized tears and 18 matched controls. We subjected biopsy samples of 3 mm in diameter to oscillatory deformation under compression using dynamic shear analysis. The storage modulus (G’) was calculated as an indicator of mechanical integrity.

Normal tendons had a significantly higher storage modulus than torn tendons, indicating that torn tendons are mechanically weaker than normal tendons (p = 0.003). Normal tendons had a significantly higher mean shear modulus than tendons with massive tears (p < 0.01).

Dynamic shear analysis allows the determination of shear mechanical properties of small tissue specimens obtained intra-operatively that could not be studied by conventional methods of tensile testing. These methods could be employed to investigate other musculoskeletal tissues. This pilot study provides some insight into mechanisms that might contribute to the failure of repair surgery, and with future application could help direct the most appropriate treatment for specific rotator cuff tears.

Previous perfusion studies of the rotator cuff have demonstrated an area of hypovascularity in the distal part of the supraspinatus tendon. This has been implicated in the pathogenesis of its rupture. We performed a quantitative histological analysis of the vascularity of the tendons of supraspinatus and infraspinatus. Vessel number, size and the percentage of the tendon occupied by vessels were measured at 5 mm intervals from the humeral insertions to the muscle bellies. Both tendons were hypovascular in their distal 15 mm. No significant difference was demonstrated between the vascularity of supraspinatus and infraspinatus. We conclude that factors other than vascularity are important in the pathogenesis of supraspinatus rupture.

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 supraspinatus tendon cell death. Recent studies have reported that hypoxia involved in rotator cuff tendon degeneration. Because antioxidants are known to scavenge for intracellular ROS, some studies have been conducted to determine whether antioxidants can reduce cell death in rotator cuff tendon-origin fibroblasts. The first study reported that an antioxidant has the ability to reduce apoptosis in oxidative-stressed rotator cuff tenofibroblasts. The second study reported that antioxidants have both antiapoptotic effects and antinecrotic effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The third study reported that an antioxidant has antiautophagic-cell-death effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The fourth study reported that glutamate markedly increases cell death in rotator cuff tendonorigin fibroblasts. The glutamate-induced cytotoxic effects were reduced by an antioxidant, demonstrating its cytoprotective effects against glutamate-induced tenofibroblast cell death. The fifth study reported that hypoxia significantly increases intracellular ROS and apoptosis. The hypoxia-induced cytotoxic effects were markedly attenuated by antioxidants, demonstrating their cytoprotective effects against hypoxia-induced tenofibroblast cell death. In conclusion, antioxidants have cytoprotective effects on tenofibroblasts exposed in vitro to an oxidative stressor, a neurotransmitter, or hypoxia. These cytoprotective effects result from antiapoptotic, antinecrotic, and antiautophagic actions involving the inhibition of ROS formation. These findings suggest that antioxidants may have therapeutic potential for rotator cuff tendinopathy. Further studies must be conducted in order to apply these in vitro findings to clinical situations

Glutamate regulates the expression of apoptosis-related genes and triggers the apoptosis of fibroblasts in rotator cuff tendons. Subacromial bursitis is always accompanied by symptomatic rotator cuff tear (RCT). However, no study has been reported on the presence of glutamate in subacromial bursa and on its involvement of shoulder pain in patients who had RCT. The purposes of this study were to determine whether the glutamate expression in subacromial bursa is associated with the presence of RCT and with the severity of shoulder pain accompanying RCT. Subacromial bursal tissues were harvested from patients who underwent arthroscopic rotator cuff tendon repair or glenoid labral repair with intact rotator cuff tendon. Glutamate tissue concentrations were measured, using a glutamate assay kit. Expressions of glutamate and its receptors in subacromial bursae were histologically determined. The sizes of RCT were determined by arthroscopic findings, using the DeOrio and Cofield classification. The severity of shoulder pain was determined, using visual analog scale (VAS). Any associations between glutamate concentrations and the size of RCT were evaluated, using logistic regression analysis. The correlation between glutamate concentrations and the severity of pain was determined, using the Pearson correlation coefficient. Differences with a probability <0.05 were considered statistically significant. Glutamate concentrations showed significant differences between the torn tendon group and the intact tendon group (P = 0.009). Concentrations of glutamate significantly increased according to increases in tear size (P < 0.001). In histological studies, the expressions of glutamate and of its ionotropic and metabotropic receptors have been confirmed in subacromial bursa. Glutamate concentrations were significantly correlated with pain on VAS (Rho=0.56 and P =0.01). The expression of glutamate in subacromial bursa is significantly associated with the presence of RCT and significantly correlated with its accompanying shoulder pain. Acknowledgements: This research was supported by the Basic Science Research Program, through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01018955 and 2017R1D1A1B03035232)

Objectives. Indocyanine green (ICG) fluorescence angiography is an emerging technique that can provide detailed anatomical information during surgery. The purpose of this study is to determine whether ICG fluorescence angiography can be used to evaluate the blood flow of the rotator cuff tendon in the clinical setting. Methods. Twenty-six patients were evaluated from October 2016 to December 2017. The participants were categorized into three groups based on their diagnoses: the rotator cuff tear group; normal rotator cuff group; and adhesive capsulitis group. After establishing a posterior standard viewing portal, intravenous administration of ICG at 0.2 mg/kg body weight was performed, and fluorescence images were recorded. The time from injection of the drug to the beginning of enhancement of the observed area was measured. The hypovascular area in the rotator cuff was evaluated, and the ratio of the hypovascular area to the anterolateral area of the rotator cuff tendon was calculated (hypovascular area ratio). Results. ICG fluorescence angiography allowed for visualization of blood flow in the rotator cuff in all groups. The adhesive capsulitis group showed significantly earlier enhancement than the other groups. Furthermore, the adhesive capsulitis group had a significantly smaller hypovascular area ratio than the other groups. Conclusion. ICG fluorescence angiography allowed for evaluation of real-time blood flow of the rotator cuff in arthroscopic shoulder surgery. The techniques of ICG fluorescence angiography are simple and easy to observe, observer reliability is high, and it has utility for evaluating blood flow during surgery. Cite this article: N. Doi, T. Izaki, S. Miyake, T. Shibata, T. Ishimatsu, Y. Shibata, T. Yamamoto. Intraoperative evaluation of blood flow for soft tissues in orthopaedic surgery using indocyanine green fluorescence angiography: A pilot study. Bone Joint Res 2019;8:118–125. DOI: 10.1302/2046-3758.83.BJR-2018-0151.R1

Background. High re-rupture rates following repairs of rotator cuff tears (RCTs) have resulted in the increased use of repair grafts to act as temporary scaffolds to support tendon healing. It has been estimated that thousands of extracellular matrix repair grafts are used annually to augment surgical repair of rotator cuff tears. The only mechanical assessment of the suitability of these grafts for rotator cuff repair has been made using tensile testing only, and compared grafts to canine infraspinatus. As the shoulder and rotator cuff tendons are exposed to shearing as well as uniaxial loading, we compared the response of repair grafts and human rotator cuff tendons to shearing mechanical stress. We used a novel technique to study material deformation, dynamic shear analysis (DSA). Methods. The shear properties of four RCT repair grafts were measured (Restore, GraftJacket, Zimmer Collagen Repair and SportsMesh). 3mm-sized biopsy samples were taken and subjected to DSA using oscillatory deformation under compression to calculate the storage modulus (G') as an indicator of mechanical integrity. To assess how well the repair grafts were matched to normal rotator cuff tendons, the storage modulus was calculated for 18 human rotator cuff specimens which were obtained from patients aged between 22 and 89 years (mean age 58.8 years, with 9 males and 9 females). Control human rotator cuff tendons were obtained from the edge of tendons during hemiarthoplasties and stabilisations. A 1-way ANOVA of all of the groups was performed to compare shear properties between the different commercially available repair grafts and human rotator cuff tendons to see if they were different. Specific comparison between the different repair grafts and normal rotator cuff tendons was done using a Dunn's multiple comparison test. Results. We report a significant difference in the shear moduli of all four rotator cuff repair grafts (P<0.0001, 1 way ANOVA, Kruskall-Wallis test). 2 of the grafts, Zimmer Collagen Repair and SportMesh, were not significantly different when compared to rotator cuff tendons and were found to have comparable shear mechanical properties (P > 0.05, Dunn's multiple comparison test). The other repair grafts, GraftJacket and Restore, had a significantly lower storage modulus when compared to human rotator cuff tendons. Conclusions. With increasing numbers of repairs of rotator cuff tears, and augmentation of these repairs, there is a need to understand the mechanical and biological properties of the both repair grafts and the tendons they are designed to augment. At present there is no clear definition of the ideal mechanobiological properties of rotator cuff repair patches. Current rotator cuff repair grafts display a wide variation in their shear mechanical properties, and how closely they are matched to the mechanical properties of human rotator cuff tendons. It is hoped that this study may help to guide surgeons in deciding on the most appropriate rotator cuff tendon repair graft

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 supraspinatus tendons across the full disease spectrum, and the short-term effects of subacromial corticosteroid injections (SCIs) and subacromial decompression (SAD) surgery on these structural characteristics. . Methods . Samples were collected inter-operatively from supraspinatus tendons containing small, medium, large and massive full thickness tears (n = 33). Using a novel minimally invasive biopsy technique, paired samples were also collected from supraspinatus tendons containing partial thickness tears either before and seven weeks after subacromial SCI (n = 11), or before and seven weeks after SAD surgery (n = 14). Macroscopically normal subscapularis tendons of older patients (n = 5, mean age = 74.6 years) and supraspinatus tendons of younger patients (n = 16, mean age = 23.3) served as controls. Ultra- and micro-structural characteristics were assessed using atomic force microscopy and polarised light microscopy respectively. . Results. Significant structural differences existed between torn and control groups. Differences were identifiable early in the disease spectrum, and increased with increasing tear size. Neither SCI nor SAD surgery altered the structural properties of partially torn tendons seven weeks after treatment. . Conclusions . These findings may suggest the need for early clinical intervention strategies for torn rotator cuff tendons in order to prevent further degeneration of the tissue as tear size increases. Further work is required to establish the long-term abilities of SCI and SAD to prevent, and even reverse, such degeneration. Cite this article: Bone Joint Res 2014;3:252–61

INTRODUCTION. In order to address high failure rates following rotator cuff repairs, a greater understanding is required of the underlying structural changes so that treatments can be appropriately targeted and biomarkers of failure can be identified. As collagen is the primary constituent of tendon and determines force transmission, collagen structural changes may affect responses to loading. For example changes in collagen 1 and 5 are associated with the hyperelastic Ehlers-Danlos syndrome, which is diagnosed by looking for pathopneumonic altered collagen fibres or ‘collagen flowers’ in skin using transmission electron microscopy (TEM). To date no study has been performed on the microstructure of torn human rotator cuff tendons using TEM. It was hypothesized that normal, small and massive human rotator cuff tendons tears will have altered microscopic structures. The unique study aimed to use TEM to compare the ultrastructure of small and massive rotator cuff tears, to normal rotator cuff tendons. METHODS. Samples from 7 human rotator cuff tendons repairs were obtained, including 4 massive (>5 cm) and 3 small (< 1 cm) tears, and 3 matched normal controls with no history of connective tissue disorders. Specimens were fixed in 4% glutaraldehyde in 0.1M phosphate buffer, processed and examined blind using routine TEM examination. To assess whether changes in the relative expression of collagen 1 and 5 (COL1A1, COL5A1 and COL5A2) occurred in all tears, qPCR was performed on another 6 phenotypically matched patients. RESULTS. The basic structure of the normal tendon consisted of tightly packed clumps of dense packed parallel running collagen fibers with few fibroblasts and small amounts of fine filamentous material between clumps. In contrast, torn samples were more variable with areas of less dense packing of collagen fibers and larger areas of filamentous material plus variable numbers of lipid droplets both within the fibroblast and between the collagen bundles. There was also evidence of twisting and random orientation of individual collagen fibers. All torn tendons showed evidence of a proportion of the fibers within the collagen bundles being enlarged with a serrated outline, similar in appearance to ‘collagen flowers’. Clear differences between the small and massive tears were not identified. qRT-PCR of torn rotator cuff tendon specimens demonstrated no altered collagen expression compared to normal tendons. DISCUSSION. This novel study has identified the previously unreported presence of atypical collagen fibers with focal swelling resulting in the appearance of ‘collagen flowers’ in torn rotator cuff tendons only. This appearance is considered pathognomonic of Ehlers-Danlos syndrome, classical type 1 and 2. Torn tendons also showed an increase in filamentous material, and infiltration with fat droplets. These novel findings may offer insight into the mechanisms of structural damage that contribute to rotator cuff failure. Further examination is required, to evaluate the significance of these observations

Aims. This study compared patients who underwent arthroscopic repair of large to massive rotator cuff tears (LMRCTs) with isolated incomplete repair of the tear and patients with incomplete repair with biceps tendon augmentation. We aimed to evaluate the additional benefit on clinical outcomes and the capacity to lower the re-tear rate. Methods. We retrospectively reviewed 1,115 patients who underwent arthroscopic rotator cuff repair for full-thickness tears between October 2011 and May 2019. From this series, we identified 77 patients (28 male, 49 female) with a mean age of 64.1 years (50 to 80). Patients were classified into groups A (n = 47 incomplete) and B (n = 30 with biceps augmentation) according to the nature of their reconstruction. Clinical scores were checked preoperatively and at six months, one year, and two years postoperatively. In preoperative MRI, we measured the tear size, the degree of fatty infiltration, and muscle volume ratio of the supraspinatus. In postoperative MRI, the integrity of the repaired rotator cuff tendon was assessed using the Sugaya classification. Tendon thickness at the footprint was evaluated on T2-weighted oblique coronal view. Results. There were no significant differences in the initial preoperative demographic characteristics. In both groups, there were significant improvements in postoperative clinical scores (p < 0.001). However, most clinical outcomes, including range of motion measurements (forward elevation, external rotation, internal rotation, and abduction), showed no differences between the pre- and postoperative values. Comparing the postoperative outcomes of both groups, no further improvement from biceps augmentation was found. Group B, although not reaching statistical significance, had more re-tears than group A (30% vs 15%; p = 0.117). Conclusion. In LMRCTs, biceps augmentation provided no significant improvement of an incomplete repair. Therefore, biceps augmentation is not recommended in the treatment of LMRCTs. Cite this article: Bone Joint J 2022;104-B(11):1234–1241

Large and retracted rotator cuff tendon tears fail to repair, or re-tear following surgical intervention. This study attempted to develop novel tissue engineering approaches using tenocytes-seeded bioscaffolds for tendon reconstruction of massive rotator cuff tendon defect in rabbits. Porcine small intestine submucosa (Restore™) and type I/III collagen bioscaffold (ACI-MaixTM) were chosen as bioscaffold carriers for autologous tenocytes. Biological characterization of autologous tenocytes was conducted prior to the implantation. The tenocyte-seeded bioscaffolds were implanted as interposition grafts to reconstruct massive rotator cuff tendon defects in rabbits. In situ re-implantation of the autologous rotator cuff tendon, excised during defect creation served as a positive control. Histological outcomes were analysed and semi-quantitatively graded at four and eight weeks after surgery. The results demonstrate that at four weeks both tenocyte-seeded bioscaffolds display inflammatory reaction similar to bioscaffold-only cuff reconstruction and the histological grading were inferior to control repair. However, at eight weeks inflammatory reaction of both tenocyte-seeded bioscaffolds were dramatically reduced as compared to bioscaffold alone. In addition, bioscaf-folds seeded with tenocytes generated similar histological appearance to that of the positive control. The implantation of autologous tenocytes on collagen-based bioscaffold offers improved rotator cuff tendon healing and remodelling compared to the implantation of bioscaffold alone

Introduction Rotator cuff degeneration is considered to be a major factor in the pathogenesis of rotator cuff tendon tear. Degenerative weakening of the rotator cuff can result in irreversible complete cuff-tear arthropathy syndrome. Recently a porcine small intestinal submucosa (SIS) has been approved by TGA as biological implant for the repair of rotator cuff tendon tear. The aims of this study are to evaluate the safety and efficacy of SIS. Methods A commercial brand of SIS was examined by histology and PCR technique. The material was implanted into mice and rabbits for the evaluation of biological reaction and inflammatory response. Next, we have used SIS to replace the rotator cuff tendon in rabbit (N=10) and compared to control (N=10). Histological examination was conducted at four and eight weeks after implantation. To further confirm if cells present in SIS material were of porcine origin, nested PCR for the amplification of DAP12 gene was used. Results Fresh SIS membrane before implantation contain multiple layers of spindle-shaped cells mixed with a small population of round-shaped cells. Chloroacetate esterase staining showed that the round-shaped cells are positive, indicating that they are mast cells. The tissue architecture of SIS mimics tendon structure as evidenced by H & E staining. The SIS membrane contained porcine DNA materials. Subcutaneous implant of SIS in mice (by six) for up to seven days showed no obvious inflammatory response or foreign body reaction. The result demonstrated that SIS has remained in the region and mixed with regenerative fibrous tissue after eight weeks. In some cases there was a massive recruitment of lymphocytes along the surface of membrane. However, no foreign body reactive giant cells were observed. Conclusions The result of this study indicated that SIS contains porcine cells and nucleic acid, which contradicts current views that SIS is a cell free biomaterial. Although no foreign body reaction of SIS was observed, SIS implant may cause chronic inflammation. Further studies should be conducted to confirm the clinical efficacy of SIS implant for rotator cuff tendon tear

Approximately 30% of general practice consultations for musculoskeletal pain are related to tendon disorders, causing substantial personal suffering and enormous related healthcare costs. Treatments are often prone to long rehabilitation times, incomplete functional recovery, and secondary complications following surgical repair. Overall, due to their hypocellular and hypovascular nature, the regenerative capacity of tendons is very poor and intrinsically a disorganized scar tissue with inferior biomechanical properties forms after injury. Therefore, advanced therapeutic modalities need to be developed to enable functional tissue regeneration within a degenerative environment, moving beyond pure mechanical repair and overcoming the natural biological limits of tendon healing. Our recent studies have focused on developing biologically augmented treatment strategies for tendon injuries, aiming at restoring a physiological microenvironment and boosting endogenous tissue repair. Along these lines, we have demonstrated that the local application of mesenchymal stromal cell-derived small extracellular vesicles (sEVs) has the potential to improve rotator cuff tendon repair by modulating local inflammation and reduce fibrotic scarring. In another approach, we investigated if the local delivery of the tendon ECM protein SPARC, which we previously demonstrated to be essential for tendon maturation and tissue homeostasis, has the potential to enhance tendon healing. Finally, I will present results demonstrating the utility of nanoparticle-delivered, chemically modified mRNAs (cmRNA) to improve tendon repair

This study aims to investigate the mechanical properties of a rotator cuff tear repaired with a polypropylene interposition graft in an ovine infraspinatus ex-vivo model. Twenty fresh shoulders from skeletally mature sheep were used in this study. A tear size of 20 mm from the tendon joint was created in the infraspinatus tendon to simulate a large tear in fifteen specimens. This was repaired with a polypropylene mesh used as an interposition graft between the ends of the tendon. Eight specimens were secured with mattress stitches while seven were secured to the remnant tendon on the greater tuberosity side by continuous stitching. Remaining five specimens with an intact tendon served as a control group. All specimens underwent cyclic loading with a universal testing machine to determine the ultimate failure load and gap distance. Gap distance increased with progressive cyclic loading through 3000 cycles for all repaired specimens. Mean gap distance after 3000 cycles for both continuous and mattress groups are 1.7 mm and 4.2 mm respectively (P = .001). Significantly higher mean ultimate failure load was also observed with 549.2 N in the continuous group, 426.6 N in the mattress group and 370 N in the intact group. The use of a polypropylene mesh as an interposition graft for large irreparable rotator cuff tears is biomechanically suitable and results in a robust repair that is comparable to an intact rotator cuff tendon. When paired with a continuous suturing technique, it demonstrates significantly resultant superior biomechanical properties that may potentially reduce re-tear rates after repairing large or massive rotator cuff tears

Introduction. The pathophysiology of high failure rates following rotator cuff tendon repairs, particularly massive tears, is not fully understood. Collagen structural changes have been shown to alter tendon thermal and mechanical properties. Thermal changes in small biopsies, detected by differential scanning calorimetry (DSC) can help to quantify collagen structural differences in torn rotator cuff tendons. This study aimed to form a quantitative rather than qualitative assessment, of whether differences in collagen structure and integrity existed between small biopsies of normal, small and massive rotator cuff tears using DSC. Methods. Thermal properties were measured for 27 human biopsies taken intra-operatively from normal, small, and massive rotator cuff tendon tears. 3 samples were taken from each patient and subjected to a modulated temperature ramp between 20–80°C at a rate of 2°C per minute with 0.318°C amplitude. The melting temperature (TM) is proposed to represent amide-amide hydrogen bond breakage and resulting protein backbone mobility. Denaturing temperature (TD) reportedly corresponds to the temperature at which the proteins fall out of solution. Denaturation enthalpy (H) should correlate with the amount of triple helical structure. Based upon a pre-study power calculation, this study had 90% power to detect a 10% difference in melting and denaturation temperature between groups with alpha=0.05. 1 specimen per patients was also frozen and cryosectioned and polarised light microscopy was used for quantitative validation. The effect of tear size on heat related parameters were performed using a one-way ANOVA test. A student's unpaired t-test was used to search for differences between individual groups (small tears, massive tears and normal tendons). Results. Small and massive rotator cuff tears had significantly higher melting temperature (TM), and denaturation enthalpy (H) compared to controls. The denaturing temperature (TD) was higher in the massive tears only compared to normal tears. No difference was detected between small and massive tears. Histology of massive tendon tears confirmed greater collagen structural disruption compared to small tears and controls. Conclusion. These novel findings suggest greater quantifiable collagen structural disruption in rotator cuff tears, compared to controls. A decrease in important thermal properties of torn tendons suggests that the material is intrinsically less stable. It is likely that torn tendons cannot withstand changes in temperature or stress as well as a perfect material could, particularly for massive tears which are more amenable to denaturation. This study offers insight into possible mechanisms for, or adaptation to, failure in tears and reduced strength

A prospective study was carried out to determine if recognised histological features seen at surgery could help predict those rotator cuff tendon repairs which re-ruptured. 40 rotator cuff tendon edge specimens from 40 patients’ shoulders were analysed histologically following routine mini-open rotator cuff repair. 32/40 underwent Ultrasonography, at a mean time of 35 months post-operatively, to determine repair integrity. The histological features seen at surgery were then compared to the repair integrity of the tendon from which it had been taken. Rotator cuff repairs that remained intact demonstrated a greater reparative response, in terms of increased fibrobast cellularity, cell proliferation and a thickened synovial membrane, than those repairs which reruptured. Larger tears which remained intact showed a higher degree of vasacularity and a significant inflammatory component than those that re-ruptured. Good tissue quality at the time of surgery allows the repair the best chance of remaining intact despite the size of the lesion. Routine histological analysis of the tissue biopsy, preformed in the post-operatively, can now aid the clinician in terms of early management and repair prognosis

Summary Statement. This study describes the design and preliminary in vitro testing of a novel patch for the repair of rotator cuff tendon tears. The laminated design incorporates woven and electrospun components. The woven element provides the patch with excellent mechanical strength and the electrospun layer improves cell attachment and promotes cell orientation and diferentiation. Introduction. Aligned nanofibrous electrospun scaffolds have been previously proposed as ideal scaffolds for tendon repair, replicating the anisotropy of tendon and providing a biomimetic design to encourage tissue regeneration (Hakimi et al., 2012). However, such scaffolds are still limited in terms of mechanical properties. This paper presents the design of a novel patch for rotator cuff repair in which the electrospun scaffold is supported by a woven component. Patients & Methods. Aligned polydioxanone (PDO) electrospun scaffolds were produced using a single nozzle electrospinning set-up with a rotating collector. The woven component was created by weaving PDO monofilaments with a manual loom. The woven and non-woven constituents were bound by a non-destructive method which preserves the surface morphology of the electrospun material. For each type of scaffold, a minimum of 3 specimens were tested to failure in tension using Zwick machine at rate of 0.3 mm/min until failure. For in vitro work, human-derived tendon cells were extracted from rotator cuff tendon tissue obtained during surgical repair, with appropriate ethical approval. Cells were cultured on the scaffolds for at least 14 days. Results. The contribution of the woven component to the tensile strength of the assembled patch is about 20 times more when compared to the electrospun scaffold. In vitro work shows that human tenocytes grown on the nanofibrous non-woven electrospun component align in the direction of the fibre orientation. The appearance of the woven component is shown. Discussion/Conclusion. While the woven component provides most of the mechanical strength, the aligned electrospun fibres enable cell orientation along the axis of the patch. These cells display a similar morphology to tenocytes in native tendons. With the combination of biomimetic features and good mechanical properties, this novel PDO patch is an excellent candidate material to support tendon repair

Background. Rotator cuff tears pose a huge socioeconomic burden. Our study uses Fourier transform infrared spectroscopy (FTIR) as it is a quick, non-manipulative and non-destructive test, which can identify a wide range of chemical targets from small intraoperatively obtained specimens. The aim of this study was (i) to characterise the chemical and structural composition of rotator cuff tendons and (ii) to identify structural differences between anatomically distinct tear sizes. Such information may help to identify specific biomarkers of rotator cuff tear pathologies, which in turn could allow early identification and monitoring of disease progression. FTIR may provide insight into the different healing rates of different tear sizes. Methods. The infrared spectra of 81 torn rotator cuff tendons were measured using a FTIR spectrometer. The rotator cuff tear sizes were classified as partial, small, medium, large and massive, and compared to 14 normal controls. All spectra were classified using standard multivariate analysis; principal component analysis, partial least square and discriminant function analysis. Results. FTIR readily differentiated between normal and torn tendons, and different tear sizes. We identified the key discriminating molecules and spectra altered in torn tendons as: (i) carbohydrates/phospholipids (1030-1200 cm. -1. ), (ii) collagen (1300-1700, 3000-3350 cm. -1. ) and (iii) lipids (2800-3000 cm. -1. ). Partial tears were chemically distinct from normal and small tears, and primarily involved a reduction in collagen type II. Conclusion. This study has demonstrated that FTIR can identify different sizes of rotator cuff tear based upon distinguishable chemical and structural features. The onset of rotator cuff tear pathology is mainly due to alterations of the collagen structural arrangements, with associated changes in lipids and carbohydrates. The approach described is rapid and has the potential to be used intraoperatively to determine the quality of the tendon and extent of disease, thus guiding surgical repairs or for monitoring of treatments

Introduction and Aims: Treatment of rotator cuff tendon tear presents a significant therapeutic challenge to surgeons. Porcine small intestinal submucosa (SIS) is a biomaterial approved by TGA and FDA for the repair of rotator cuff tendon tear. The aims of this study are to evaluate the safety and efficacy of SIS. Method: SIS purchased from DePuy Johnson & Johnson was examined by histology and PCR technique. The material was also implanted into mice and rabbits for the evaluation of biological reaction and inflammatory response. Porcine immunoreceptor DAP12 gene was used to examine if the material contained porcine DNA. Results: Fresh SIS membrane before implantation contains multiple layers of spindle-shaped cells mixed with a small population of round-shaped cells. Chloro-acetate esterase staining showed that the round-shaped cells are positive, indicating that they are mast cells. The tissue architecture of SIS mimics to tendon structure as evidenced by H& E staining. To further confirm if cells present in SIS material were porcine origin, nested PCR for the amplification of DAP12 gene was used. The result demonstrated that SIS membrane contain porcine DNA materials. Conclusion: SIS contains porcine cells and nuclei acid, which contradicts with current views that SIS is a cell-free biomaterial. Although no foreign body reaction of SIS was observed, SIS implant may cause chronic inflammation. Further studies should be conducted to confirm the clinical efficacy of SIS implant

Aims: The aim of the study was to investigate the cap-suloligamentous structures of the shoulder joint and their association with rotator cuff tendons. Methods: Twenty seven alcohol-formalin-glycerol þxed right shoulder joints (age range 65 Ð 78 years) were investigated. The Ligg. coracohumerale, coracoglenoidale, glenohumeralia, semicirculare humeri and gleno-capsulare were dissected in þne detail. To visualise the rotator interval, the Processus coracoideus was cut at its base and moved together with the Ligg. coracohumerale and coracoglenoidale posteriorly. The analysis of the ligamentous structures and their relations with the rotator cuff tendons was performed. Results: The Lig. coracohumerale originated from Processus coracoideus and Lig. coracoglenoidale. It inserted into the Lig.semicirculare humeri Ð a capsular ligament spread between Tubercula minus et majus. Lig. glenocapsulare originated posterior to the Tuberculum supragle-noidale and inserted into the Lig. semicirculare humeri. The Mm. supra- and infraspinatus inserted into the Lig. semicirculare humeri. The anterior capsule was strengthened in addition to the three Ligg. glenohumeralia with a Lig. glenohumerale spirale. It originated from the Tuberculum infraglenoidale, coursed craniolaterally and inserted together with the M. subscapularis tendon at the Tuberculum minus. Conclusions: The shoulder joint capsule is strengthened with the Ligg. coracohumerale, coracoglenoidale, glenohumeralia superior, medium, inferior et spirale and Ligg. semicirculare humeri et glenocapsulare. The close relation of the ligamentous structures with the tendons of the rotator cuff brings a new insight into the different glenohumeral pathologies

Introduction: New biotechnologies create opportunities for gene therapy to promote rotator cuff healing. We have previously demonstrated that genetically engineered mesenchymal stem cells (MSCs) over expressing BMP-2 and SMAD8 signaling molecule differentiate to tenocytes in vitro and in vivo. Therefore, we hypothesized that rotator cuff defect could be regenerated using genetically engineered MSCs. Method: Nonviral methods were utilized to establish genetically engineered MSCs that co-express BMP-2 and the Smad8 signaling molecule. A previously validated animal model was utilized to examine rotator cuff healing. A 2mm x2mm full thickness defect was created in the infraspinatus tendon of 8 nude rats. A collagen-I biomembrane (TissueMend) containing 3 x 10. 6. engineered cells was sewn into the defect. An identical control procedure was repeated on the contralateral side with biomembrane containing non-engineered MSCs. Results: 4 weeks post implantation the area of implantation was isolated and analyzed by light microscopy and histochemical staining. Analysis of the engineered implants revealed the formation of dense connective tissue with parallel-organized fibers and spindle shaped cells, unlike the control samples. Proton Double Quantum Filtered Magnetic Resonance Imaging technique of the rotator cuff tendons demonstrated an increased presence of organized collagen fibers within the engineered rotator cuff tissue when compared with either native rotator cuff or those treated with non-engineered MSCs. Conclusion: This is the first report showing rotator cuff tendon repair using genetically engineered MSCs. Moreover these findings may have considerable importance for tendon healing and may indicate a clinical gene therapy platform to augment surgical repair

Aim To determine if tissue metabolism varies in supraspinatus tendons with distance from the edge of the rotator cuff tendon tear and also with differing size of tear. Background Tissue metabolism can be assessed by measuring oxygen and nitrous oxide concentrations within the tissue. Viable tendon tissue consumes oxygen and contains nitrous oxide (used in the general anaesthetic) from the blood stream. Non-viable tendon tissue will not consume oxygen but will contain nitrous oxide. Methods Oxygen and Nitrous Oxide concentrations were measured amperometrically using silver needle microelectrodes. The needle was inserted into the supraspinatus tendon of patients with massive, large, medium and small full thickness rotator cuff tears and patients with partial thickness and no tears. Patients undergoing open stabilisation were used as controls. Measurements were made at a number of quantifiable points from the tendon edge to allow the creation of a topographical map of tissue metabolism. Oxygen consumption was calculated using measured oxygen and nitrous oxide levels at each point. Results In patients with rotator cuff tears oxygen consumption was significantly lower near to the edge of the tear. Patients with impingement syndrome but no evidence of a rotator cuff tear also showed a decreased level of oxygen consumption in the anterior part of supraspinatus, but this was significantly higher than the levels seen in the torn tendon. The control group showed no significant alteration in oxygen levels. Conclusion Patients with rotator cuff tendon tear demonstrate significantly reduced levels of tissue metabolism. This reduction in tissue viability is significantly greater at the edge of the tear and in larger tears. Patients with intact tendons and impingement syndrome also demonstrate minor reduction in tissue tendon viability compared with controls

Rotator cuff tears are a common cause of shoulder pain and dysfunction. Therefore, the purpose of this in-vitro biomechanical study was conducted to determine the effects of simulated tears and subsequent repairs of the rotator cuff tendons on joint kinematics. Eight paired fresh-frozen cadaveric shoulder specimens (mean age: 66.0 ± 8.7 years) were tested using a custom loading apparatus designed to simulate unconstrained motion of the humerus. Cables were sutured to the rotator cuff tendons and the deltoid. Loads were applied to the cables based on variable ratios of electromyographic (EMG) data and average physiological cross-sectional area (pCSA) of the muscles. An electromagnetic tracking device (Flock of Birds, Ascension Technologies, VT) was used to provide real-time feedback of abduction angle, to which the loading ratio was varied correspondingly. 2 and 4cm tears were made starting at the rotator cuff interval and extending posteriorly. Specimens were randomised to receive either single or double suture anchor repair. In order to quantify repeatability, five successive tests on each of the intact, torn, and repaired cases were performed. Statistical significance was established using One- and Two-way Repeated Measured ANOVAs (p< 0.05). Rotator cuff tears caused alteration in glenohumeral kinematics. A 2cm tear caused the humerus to consistently move posterior through the arc of abduction; however, as the tear increased to 4cm the humerus moved anteriorly, returning towards the intact state. Double row suture anchor repairs more accurately reproduced the kinematics of the intact specimen compared to single row suture anchor repair. The initial posterior displacement in the plane of elevation with the sectioning of the supraspinatus is related to the diminished anterior moment on the glenohumeral joint. As the tear proceeds into the infraspinatus, the anterior and posterior forces become more balanced and a return to near normal intact kinematics was observed. This study demonstrates that double row suture anchor repair more accurately reproduces active shoulder kinematics of the intact shoulder specimens

Purpose: To determine if administration of recombinant bFGF in an alginate gel would increase early healing mechanical parameters in acutely injured rat rotator cuff tendon at specific time points. Method: Sprague Dawley rats were randomly divided into 2 groups and had surgically created 1mm (half tendon width) full thickness injuries at exactly 2mm from insertion site of Infraspinatus on the humerus. 200ng of bFGF or vehicle control was administered to randomly chosen rats. Tendons were harvested at 1 week, 2 weeks and 4 weeks. In both groups, the Infraspinatus tendon was dissected, and left attached to the humerus. At the time of testing, the intact portion of the injured tendon was divided sharply across tendon fibers at the level of the injury leaving only the healing tissue callus in continuity with the remaining proximal and distal portions of the tendon and loaded to failure. Results: At 1 week the injury group’s average load to failure was 0.60N versus 0.61N in the bFGF injury group P = 1.000. At 2 weeks the injury group’s average load to failure increased to 1.03N versus 2.08N in the bFGF injury group P = 0.440 At 4 weeks the injury group’s average load to failure increased to 3.93N versus 5.56N in the bFGF injury group P = 0.008 representing a 41% increase in ultimate load. At 4 weeks, callus size of the injury group was 0.4mm2 versus 2.7mm2 in the bFGF injury group P < 0.001. Stiffness at 4 weeks for the injury tendons was 2.15 N/mm versus 3.54 N/mm in the bFGF group P = 0.008. Conclusion: At 4 weeks healing tissue of acutely injured rotator cuff exposed to bFGF has an increase in ultimate load to failure (41% compared to control), increase in tendon callus size and stiffness. Our findings suggest a role of bFGF or similar growth factors in accelerating the healing of injured rotator cuff tendon

Background: Time dependent, quantitative studies of muscle atrophy or passive muscle mechanics following chronic muscle detachment have not been previously reported. We developed a chronic tear of the rotator cuff tendon in a canine model to investigate and quantify the time related changes in the passive mechanics, volume, and fat of the infraspinatus muscle. We hypothesize that infraspinatus muscle stiffness will increase, volume will decrease, and fat content will increase at 12-weeks following tendon detachment. Methods: The right infraspinatus tendons of eight adult mongrel dogs were surgically detached from the proximal humerus. The non-operated left shoulder served as a control. Muscle volume changes were quantified using MRI scans. At 12 weeks the passive mechanical properties of the chronically detached and control muscles were determined intraoperatively using a custom device. Intramuscular fat was evaluated histologically at sacrifice. Results: After 12 weeks of detachment, the stiffness and modulus were significantly increased in the detached infraspinatus muscles relative to controls. MRI analysis demonstrated that the detached muscle volumes decreased by 33 percent in the first 6 weeks and remained constant thereafter. Intramuscular fat increased significantly in the detached muscles, and to a greater extent in the lateral regions. Conclusions: The chronically detached muscle is not merely a smaller version of the original muscle but rather a “different” muscle. The detached muscle becomes stiffer and the passive loads required to repair it can become excessive. A significant reduction in muscle volume occurs within days to weeks following tendon detachment. The non-uniformity of muscle fat changes suggests that fat content should be used cautiously as an indicator of muscle quality. Clinical Relevance: Clinically, chronic, large rotator cuff tendon tears are observed to have a qualitatively shorter and stiffer muscle-tendon unit than normal. We have developed a chronic rotator cuff model to quantitatively investigate changes in the detached infraspinatus muscle. The passive mechanical properties of a chronically torn rotator cuff muscle-tendon unit may be a useful predictor of reparability and clinical outcome

Tears of the rotator cuff tendons are a very common entity. Despite recent advances in arthroscopic rotator cuff repair, the re-tear rate remains high. Thus, new methods to improve healing rates following rotator cuff repair must be sought. The purpose of this prospective randomized double-blind controlled study is to compare the functional outcomes and healing rates of an adjuvant pre-operative bone microfracture technique prior to arthroscopic cuff repair. Patients undergoing arthroscopic rotator cuff repair were randomized to receive either a percutaneous bone microfracture of the supraspinatus footprint or a “soft tissue needling” technique, in which the pin was passed through the peripheral edges of the rotator cuff, five-seven days prior to index surgery, under ultrasound guidance. Follow-ups were completed at 3, 6, 12 and 24 months post-operatively. Healing status was determined by ultrasound at 6 and 24 months. The primary objective was to compare the WORC score at 24 months. Secondary objectives included the healing status via ultrasound, the Constant, and the ASES scores. A sample size calculation determined that 90 patients provided 80% power to detect a statistical difference between groups. Baseline demographic data did not differ between groups. No statistical differences were detected in the WORC outcome at any time points (p=0.47, baseline, p=0.60, 3 months, p=0.79, 6 months, p=0.50, 12 months, p=0.54, 24 months). Healing rates did not differ between groups (P=0.34) and no differences were observed in the ASES or Constant Scores at all time-points. Statistically significant improvements occurred in both groups from baseline to all time points in all clinical outcome scores (p < 0 .0001). No statistically significant differences in primary or secondary outcomes were identified between pre-operative bone microfracture and soft tissue needling techniques prior to arthroscopic rotator cuff repair. This study does not support pre-operative microfracture as a adjuvant technique prior to arthroscopic cuff repair

Introduction: The Nottingham Hood is a polyester soft tissue reinforcement device for the treatment of weakened or torn rotator cuff tendons (RCTs). The device was introduced in 1987 and has undergone a number of modifications from a close weave polyester modified aortic vascular graft (Mark 1) to an embroidered trefoil shape (Mark 4 – Pearsall’s Ltd) which has now been available since 2000. While this device has been under development it has been used on a named patient basis for 10 years on humanitarian grounds as an alternative treatment option for patients with massive RCTs. Approximately 30 Nottingham Hoods have been inserted over the past 10 years. This study investigates the histological changes and ingrowth associated with this device. Methods: Four patients who have had the Nottingham Hood inserted for massive RCTs have had re-operations for various reasons on five occasions. Excised material from the rotator cuff has been subjected to histological investigation. Excised biopsy material has been obtained 6 weeks, 6, 9 & 12 months and 14 years following implantation. Transmitted and polarised light microscopy has been used in all cases. Results: At 6 weeks birefringent clear material similar to suture material was identified, invested by fibrin and occasional red cells i.e. old thrombus. The fibrin was partly calcified and insinuated between bundles of the meshwork material. No true ingrowth of material was seen at this stage. At 6 months the material was seen macroscopically to be covered with collagenous material, rather like fascia which interdigitated closely with the embedded polyester material. At 14 years the mesh appeared to be invested, sandwich-like into a collagenous fascia-like structure with dense hyaline bands of collagen. Some fibrin was also present between the fibrils and a low grade foreign body giant cell response with light chronic inflammation. The local synovium showed detritic synovitis. Discussion: The histological features show that there is an early organisational response to the insertion of the new tissue, which is then accompanied by long-term incorporation into host tissues by fibrosis and scarring. A small fibrin and foreign body response lingers on. Conclusion: This long-term follow-up assessment provides evidence that long-term implantation of polyester as reinforcement for the rotator cuff tendons is not associated with serious biological problems. However the problem of stretching of the repaired rotator cuff muscles does occur and needs to be considered in more depth

The Nottingham Hood is a polyester soft tissue reinforcement device for the treatment of weakened or torn rotator cuff tendons (RCTs). The device was introduced in 1987 and has undergone a number of modifications from a close weave polyester modified aortic vascular graft (Mark 1) to an embroidered trefoil shape (Mark 4 – Pearsall’s Ltd) which has now been available since 2000. While this device has been under development it has been used on a named patient basis for 10 years on humanitarian grounds as an alternative treatment option for patients with massive RCTs. Approximately 30 Nottingham Hoods have been inserted over the past 10 years. This study investigates the histological changes and ingrowth associated with this device. Four patients who have had the Nottingham Hood inserted for massive RCTs have had re-operations for various reasons on five occasions. Excised material from the rotator cuff has been subjected to histological investigation. Excised biopsy material has been obtained 6 weeks, 6, 9 & 12 months and 14 years following implantation. Transmitted and polarised light microscopy has been used in all cases. At 6 weeks birefringent clear material similar to suture material was identified, invested by fibrin and occasional red cells i.e. old thrombus. The fibrin was partly calcified and insinuated between bundles of the meshwork material. No true ingrowth of material was seen at this stage. At 6 months the material was seen macroscopically to be covered with collagenous material, rather like fascia which interdigitated closely with the embedded polyester material. At 14 years the mesh appeared to be invested, sandwich-like into a collagenous fascia-like structure with dense hyaline bands of collagen. Some fibrin was also present between the fibrils and a low grade foreign body giant cell response with light chronic inflammation. The local synovium showed detritic synovitis. The histological features show that there is an early organisational response to the insertion of the new tissue, which is then accompanied by long-term incorporation into host tissues by fibrosis and scarring. A small fibrin and foreign body response lingers on. This long-term follow-up assessment provides evidence that long-term implantation of polyester as reinforcement for the rotator cuff tendons is not associated with serious biological problems. However the problem of stretching of the repaired rotator cuff muscles does occur and needs to be considered in more depth

Background. Rotator cuff atrophy evaluated with computed tomography scans has been associated with asymmetric glenoid wear and humeral head subluxation in glenohumeral arthritis. Magnetic resonance imaging has increased sensitivity for identifying rotator cuff pathology and has not been used to investigate this relationship. The purpose of this study was to use MRI to assess the association of rotator cuff muscle atrophy and glenoid morphology in primary glenohumeral arthritis. Methods. 132 shoulders from 129 patients with primary GHOA were retrospectively reviewed and basic demographic information was collected. All patients had MRIs that included appropriate orthogonal imaging to assess glenoid morphology and rotator cuff pathology and were reviewed by two senior surgeons. All patients had intact rotator cuff tendons. Glenoid morphology was assigned using the modified-Walch classification system (types A1, A2, B1, B2, B3, C, and D) and rotator cuff fatty infiltration was assigned using Goutallier scores. Results. 46 (35%) of the shoulders had posterior wear patterns (23 type B2s, 23 type B3s). Both the infraspinatus and teres minor independently had significantly more fatty infiltration in B2 and B3 type glenoids compared to type A glenoids (p<0.001). There was a greater imbalance in posterior rotator cuff muscle fatty atrophy in B2 and B3 type glenoids compared to type A glenoids (p<0.001). However, there was no difference in axial plane imbalance between B2 and B3 glenoids (p=1.00). There was increased amount fatty infiltration of the infraspinatus among B2 and B3-type glenoids compared to type A glenoids on multivariate analysis controlling for age and gender (p<0.001). Conclusions. These results identify significant axial plane rotator cuff muscle imbalances in B2 and B3-type glenoids compared to concentrically worn glenoids, favoring a relative increase in fatty infiltration of the infraspinatus and teres minor compared to the subscapularis in glenoids with patterns of posterior wear. For any figures or tables, please contact authors directly

Introduction and Aims: Large or recurrent rotator cuff tendon tears are difficult to treat effectively. Collagen bio-scaffolds have become available to reinforce a tendon repair or as an interpositional graft. This study compares the suitability of two collagen bio-scaffolds for autologous tenocyte implantation, and assesses the in vivo rotator cuff healing response with these grafts in a rabbit model. Method: Tenocytes were isolated from rabbit tendon, cultured and seeded onto the Restore patch (DePuy), or the Matricel (Verigen) collagen membrane. Serial scanning electron microscopy examined tenocyte integration with the bio-scaffold, and extra-cellular matrix synthesis over time. A rotator cuff tendon defect was created in 50 rabbits and repaired by either: a) direct suture to tuberosity; b) Matricel interposition graft; c) Matricel interposition with autologous tenocytes; d) Restore patch interposition graft; e) Restore patch interposition with autologous tenocytes. Gross and histological evaluation were performed at four weeks and eight weeks post-surgery. Results: Scanning electron microscopy of the Matricel membrane showed a rough surface characterised by a loose arrangement of collagen fibres capable of cell adhesion. SEM at one, three and five days after cell seeding, showed progressive integration of tenocytes into the three-dimensional membrane structure with extra-cellular matrix neosynthesis in the spaces between the native collagen fibres. SEM of the Restore patch showed a relatively smooth surface of highly compacted collagen fibres. Serial SEM after cell seeding showed relatively less tenocyte integration onto the membrane surface though tenocyte replication and matrix neo-synthesis was observed. All 50 rabbits regained normal gait at two weeks post-surgery. At sacrifice, no tendon ruptures had occurred at either time point in any of the five groups. At four weeks, the Matricel and Restore bio-scaffold membranes were partially absorbed, and a florid lymphocytic inflammatory response was evident surrounding the remaining membrane. By eight weeks, graft tissue had been resorbed further, the inflammatory response had decreased, and the regenerating tendon showed progressive remodelling. Autologous tenocyte implantation on both membranes improved the reparative tendon histological grade at eight weeks compared to membranes without cell implantation, and was equivalent to the direct repair group. Conclusion: Autologous tenocytes can be implanted onto both Matricel and Restore collagen bio-scaffolds. Though both Xeno grafts induce an anti-inflammatory response in vivo, membrane resorption subsequently occurs. The healing response of large rotator cuff defects treated with interpositional collagen grafts is improved with autologous tenocyte implantation in a rabbit model

Surgical reattachment of torn rotator cuff tendons can lead to satisfactory clinical outcome but failures remain common. Ortho-R product is a freeze-dried formulation of chitosan (CS) that is solubilized in platelet-rich plasma (PRP) to form injectable implants. The purpose of the current pilot study was to determine Ortho-R implant acute residency, test safety of different implant doses, and assess efficacy over standard of care in a sheep model. The infraspinatus tendon (ISP) was detached and immediately repaired in 22 skeletally mature ewes. Repair was done with four suture anchors in a suture bridge configuration (n = 6 controls). Freeze-dried formulations containing 1% w/v chitosan (number average molar mass 35 kDa and degree of deacetylation 83%) with 1% w/v trehalose (as lyoprotectant) and 42.2 mM calcium chloride (as clot activator) were solubilized with autologous leukocyte-rich PRP and injected at the tendon-bone interface and on top of the repaired site (n = 6 with a 1 mL dose and n = 6 with a 2 mL dose). Acute implant residency was assessed histologically at 1 day (n = 2 with a 1 mL dose and n = 2 with a 2 mL dose). Outcome measures included MRI assessment at baseline, 6 weeks and 12 weeks, histopathology at 12 weeks and clinical pathology. MRI images and histological slides were scored by 2 blinded readers (veterinarian and human radiologist, and veterinarian pathologist) and averaged. The Generalized Linear Model task (SAS Enterprise Guide 7.1 and SAS 9.4) was used to compare the different groups with post-hoc analysis to test for pairwise differences. Ortho-R implants were detected near the enthesis, near the top of the anchors holes and at the surface of ISP tendon and muscle at 1 day. Numerous polymorphonuclear cells were recruited to the implant in the case of ISP tendon and muscle. On MRI, all repair sites were hyperintense compared to normal tendon at 6 weeks and only 1 out 18 repair sites was isointense at 12 weeks. The tendon repair site gap seen on MRI, which is the length of the hyperintense region between the greater tuberosity and tendon with normal signal intensity, was decreased by treatment with the 2 mL dose when compared to control at 12 weeks (p = 0.01). Histologically, none of the repair sites were structurally normal. A trend of improved structural organization of the tendon (p = 0.06) and improved structural appearance of the enthesis (p = 0.1) with 2 mL dose treatment compared to control was seen at 12 weeks. There was no treatment-specific effect on all standard safety outcome measures, which suggests high safety. Ortho-R implants (2 mL dose) modulated the rotator cuff healing processes in this large animal model. The promising MRI and histological findings may translate into improved mechanical performance, which will be assessed in a future study with a larger number of animals. This study provides preliminary evidence on the safety and efficacy of Ortho-R implants in a large animal model that could potentially be translated to a clinical setting

Recent studies on animal models focused on the effect of preserving tendon remnant of rotator cuff on tendon healing. A positive effect by combining tendon remnant preservation and small bone vents on the greater tuberosity in comparison with standard tendon-to-bone repair has been shown. The purpose of the present clinical study was to evaluate the efficacy of biologic augmentation of arthroscopic rotator cuff repair by maintaining tendon remnant on rotator cuff footprint combined with small bone vents of the greater tuberosity. A retrospective study was conducted. All patients who underwent arthroscopic rotator cuff repair associated with small bone vents (nanofractures) and tendon footprint preservation were considered eligible for the study. Inclusion criteria were: diagnosis of full-thickness rotator cuff tear as diagnosed at preoperative magnetic resonance imaging (MRI) and confirmed at the time of surgery; minimum 24-month of follow-up and availability of post-operative MRI performed not earlier than 6 months after surgery. Exclusion criteria were: partial thickness tears, irreparable tears, capsulo-labral pathologies, calcific tendonitis, gleno-humeral osteoarthritis and/or previous surgery. Primary outcome was the ASES score. Secondary outcomes were: Quick-DASH and WORC scores, and structural integrity of repaired tendons by magnetic resonance imaging (MRI) performed six months after surgery. A paired t-test was used to compare pre- and postoperative clinical outcomes. Subgroup analysis was performed according to tear size. Significance was set at p < 0.05. The study included 29 patients (M:F = 15:14). Mean age (+ SD) of patients was 61.7 + 8.9 years. Mean follow-up was 27.4 ± 2.3 months. Comparison between pre- and postoperative functional scores showed significant clinical improvement (p < 0.001). Subgroup analysis for tear size showed significant differences in the QuickDASH score (0.04). Particularly, a significant difference in the QuickDASH score could be detected between medium and large tears (p=0.008) as well as medium and massive lesions (p=0.04). No differences could be detected between large and massive tears (p= 0.35). Postoperative imaging showed healed tendons in 21 out of 29 (72%) cases. Preservation of tendon remnant combined with small bone vents in the repair of medium-to-massive full-thickness rotator cuff tears provided significant improvement in clinical outcome compared to baseline conditions with complete structural integrity in 72% of the cases

Purpose:. The objective of this study was to determine the tensile strength of the different components of the rotator cuff tendons and their relationship to rotator cuff tears. Method:. The tests were done on a newly designed and built test-bench that performed the tests at a consistent rupture speed. The tests were done on four fresh frozen cadaver shoulders. The capsular and tendinous layers of the rotator cuff were divided leaving them only attached on the humeral side. Separate tensile tests were done on these tendons, after they were divided into 10 mm wide strips before testing. The tendon thickness was also measured. Results:. The maximum force tolerated by these tendons is comparable. The elongation however is not the same; the tendinous part of the tendon elongated more. The strength of the “rotatorhood” was then determined. This is a thin layer of tendon extending beyond the greater tuberosity, connecting the supra-spinatus to the sub-scapularis via the bicipital groove. The 10 mm of the “rotator hood” ruptured at an average force of 70 Newtons. Conclusion:. 1. The two layers of the rotator cuff contribute equally to the cuff's strength. 2. The difference in elongation of the tendinous and capsular layers makes the capsular layer more vulnerable to elongation stress. 3. The “rotatorhood” is a strong important structure with a mechanically advantageous insertion

Anatomy of the rotator cuff tendons, their relationship to the greater tuberosity, and the tensile and compressive properties of the cuff tendons have been extensively studied recently. From these anatomical and biomechanical studies, it has been clarified that stress concentration at the anterior portion of the supraspinatus tendon, shearing force, and mechanical friction as well as the degenerative weakness of the cuff tendons can all play a role in the occurrence of a tear. Strength of initial repair is limited, and thus the arm after repair should be positioned such that undue tension at the repair site is eliminated

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 supraspinatus tendon with weights. A pressure sensor was placed between the supraspinatus tendon and the acromion. After pressure measurements for 15 cycles of each motion type, the InSpace balloon (OrthoSpace, Inc, Israel) was inserted and the specimens tested and pressure measured again for 15 cycles. Statistically significant changes in peak pressures were then measured before and after balloon. Peak pressures were measured near 90 degrees abduction. No statistical differences were observed for internal-external rotation before and after balloon-shaped subacromial spacer was inserted. Mean pressures in abduction-adduction were significantly reduced from 121.7 ± 9.5 MPa to 51.5 ± 1.2 MPa. Peak pressures after repair were 1171.3 ± 99.5 MPa and 1749.6 ± 80.7 MPa in flexion-extension and abduction-adduction motion, respectively, and significantly decreased to 468.7 ± 16.0 MPa and 535.1 ± 27.6 MPa after spacer insertion (p<0.0001). The use of the spacer above the repaired tendon reduced peak pressures and distributed them more widely over the sensor during both abduction-adduction and flexion-extension motions and therefore can reduce the stress on the rotator cuff repair. The InSpace system may reduce the pressure on the repaired tendon, thus potentially protecting the repair. Further studies to investigate this phenomenon are warranted, in particular relating these changes to shoulder kinematics following tear repair and spacer insertion

The health of a synovial joint is relied on normal function and coordination of a group of tissues such as articular cartilage (AC), ligaments, tendons and muscles. Osteoarthritis (OA), which is the most common joint disease, is clinically characterised by lesion of AC. Despite this, injury of a ligament or tendon or muscle generates a joint instability, which accelerates deterioration of AC and progression of OA. Traditional histology is often used to study the pathology of biological tissues. It requires tissue biopsy, which traumatises the donor tissues. Therefore, it is not an idea method for assessing AC, ligaments and tendons as the tissues have a poor healing capability. There is a worldwide demand of an imaging technique that diagnoses the microstructural changes of chondral and connective tissues without biopsy. Confocal arthroscopy (Optiscan Pty Ltd, Australia) possesses a Ø 6.3 mm probe and offers a 0.7 µm lateral imaging resolution and 7 µm axial resolution. It has been successfully used for examining the internal microstructural disorders in rotator cuff tendons of human cadavers without tissue biopsy (WU et al., 2015). This study investigates the capability of confocal arthroscopy as optical histology for assessing the internal microstructure of AC, ligaments, tendons and muscles in a knee joint. Four sheep keen joints were freshly donated by other research unrelated to this study. After 5 ml clinical grade fluorescein solution at 0.05 g/L was injected into the joint cavity of a knee joint, the joint was passively exercising for about 10 minutes. The joint was then open collaterally and washed thoroughly using PBS for acquiring the microstructure of AC, ligaments, tendons and muscles using the confocal arthroscopy. Results: without biopsy, confocal arthroscopy offers an imaging resolution for onsite distinguishing the subtle microstructural difference of AC in the weight-bearing and non-weight bearing region. It also permitted visualising the hierarchical collagen structure in ligaments and tendons at a fibre level, and characterising the muscle nuclei, motor-neurons, moto-neuron synapse and striates of myofibres. Confocal arthroscopy showed the early promise to act as optical histology for studying the microstructure of chondral and a range of connective tissues, which allows understand better the health status of a knee joint. Since a sheep knee joint is very small for operating a normal procedure of an arthroscopic examination, an open knee joint surgery was performed in this study to allow imaging the microstructure of AC and a range of connective tissues. This is accounted as a limitation in the study. Nevertheless, this study demonstrated the development of confocal arthroscopy may lead to optical histology of the internal microstructure of AC and a group of connective tissues, which offers understanding more comprehensively the healthy status of a knee joint

Forty-two shoulders in 37 patients with polyarthritis were treated with Neer total shoulder replacements and reviewed 12 to 66 months afterwards. There was good pain relief and improvement in function, but the range of movement was less than that seen after replacements for osteoarthritis; this may have been related to the fact that 34 shoulders had abnormal rotator cuff tendons. Although there was a high incidence of radiolucent lines around the glenoid component, there was no clinical evidence of loosening. There were a few complications, but on the whole we feel that the Neer total shoulder arthroplasty is a valuable procedure for a patient with polyarthritis

This is a retrospective review of 108 patients who underwent decompressive anterior acromioplasty for chronic impingement in the absence of a full thickness rotator cuff tear. Before operation, all the patients had had shoulder pain for at least one year despite conservative treatment. At operation, the rotator cuff tendons were explored and were intact. Anterior acromioplasty, followed by rehabilitation was successful in 87% of patients. The operation was less successful in women, in those who had diminished movement before operation, who were involved in worker's compensation claims, and whose pain followed direct trauma. Appropriate selection of patients is considered the key to success

Massive, irreparable rotator cuff tears occur in about 15% of patients with ruptures of the rotator cuff tendons. There is no consistently agreed management for irreparable rotator cuff tears, however, latissimus dorsi tendon transfer is a recognised technique. We aimed to review the functional outcome of patients undergoing this operation at a single tertiary referral centre. Fourteen latissimus dorsi transfer procedures in thirteen patients from May 2007 to May 2008 were retrospectively reviewed. The mean age of patients undergoing the procedure was fifty nine years. All patients were confirmed to have massive, irreparable (>5cm) rotator cuff tears as determined by MRI or ultrasound. Modified Constant scores (assessing shoulder pain, functional activity and movement) determined pre-operatively and post latissmus dorsi transfer were compared. The mean duration of follow up was 12 months. The mean Modified Constant Score (maximum = 75) improved from 23 points pre-operaively to 52 points post latissimus dorsi transfer (p < 0.05). All patients had improvement in shoulder pain following the operation. There was a trend for younger patients to have greater improvement in functional activity and shoulder movement. From our series, latissimus dorsi transfer is effective at improving functional outcomes in patients with massive, irreparable rotator cuff tears, especially in younger age groups

The objective of this study was to determine the tensile strength of the different components of rotator cuff tendons. A test bench that performs tests at consistent rupture speed was used to do separate tensile tests on 10-mm strips of capsular and tendinous layers in four fresh frozen cadaveric shoulders. The layers were left attached only on the humeral side. The maximum force was comparable but the elongation of the outer part of the tendon was greater, indicating that the capsular part would tear first. On average, a 10-mm strip of capsular layer failed at 170N with elongation of 7 mm, while a 10-mm strip of tendinous layer failed at 230N with elongation of 10 mm. Using six fresh frozen cadaveric shoulders, we went on to determine the strength of the rotator hood, a thin layer of tendon extending beyond the tuberosity major and connecting the supraspinatus to the subscapularis via the bicipital tunnel. The rotator hood ruptured at a mean force of 70 N. We concluded that the two layers of the cuff contribute equally to the strength. It is therefore important to repair both layers. The difference in elongation of the tendinous and capsular layers makes the capsular layer more vulnerable to elongation stress. The rotator hood is a strong and important structure, and it is important to repair it

The aim of this study was to determine cell viability in different stages of rotator cuff tendon tears using a cell viability molecular probe. Surgical biopsies taken from the edge of the Supraspinatus tendon tear from12 patients, 5 women and 7 men, mean age of 61 years were subjected to a cell viability assay using Molecular Probes Live/Dead cell viability assay. Specimens were then incubated with Calcein-AM and Ethidium Homodimer-1 and following snap freezing, sections were viewed under fluorescent microscopy. Cells which remained metabolically active fluoresced green, whereas dead cells were red. Populations of live and dead cells were counted for each specimen on ten high powered (x400 magnification) fields of view. The results show that the percentage of live cells is reduced in large chronic degenerate tears but greatest in acute traumatic tears. In addition, for those cases where tissue was assayed from the edge of the tear and 1 cm more proximally, there was a considerable increase in the percentage of viable cells in more proximal tissue. Use of this simple assay demonstrates high cell viability and consequently good quality tissue in traumatic tears, but lower quality tissue in larger more degenerate tears. This suggests that traumatic lesions have a high propensity to heal while larger more degenerate tears are less likely to heal but have better quality tissue more proximally

To analyze the relationship between functional outcome and tissue quality after arthroscopic rotator cuff repair. One hundred and forty-five patients who had undergone arthroscopic repair of rotator cuff tear, during the period of 2003–2008, were evaluated. All operations were performed under the same surgeons. The mean follow-up period was 2.4±1.2 years (range, 0.5 to 5 ys). The patients were devided in two groups:. patients with good tissue quality and. patients with poor tissue quality. As good tissue quality is defined the tendon with enough mass for suturing (thickness> 3mm) and good elasticity (the footprint is covered properly under tendon traction with tissue grasper). The independent variable studied here was the tissue quality of rotator cuff tendon. Clinical outcomes preoperatively and postoperatively, were assessed with use of ASES, CONSTANT and UCLA scores. Statistical analysis was performed by using STATA 8.0. Good tissue quality was identified in 119 patients (82%) and poor tissue quality in 26 (18%) patients respectively. At the follow up the patients with good tissue quality achieved Constant score: 86.85±12.49, ASES score: 84±3.4, UCLA score: 28.7±1.9 and the patients with poor tissue quality achieved Constant score: 62.35±13.85, ASES score: 61.49±8.9, UCLA score: 21±3.2. Significant difference between the two groups concerning the clinical outcome was observed after adjusted the data for age. Besides high correlation was noticed between old age and increased rate of poor tissue quality (r=0.88). Better clinical outcomes are expected in patients associated with good tissue quality, adjusted for age. So the tissue quality is positively correlated with the final functional outcome

Given that there is limited time available to the surgeon in arthroscopic rotator cuff repair, how is the time best spent? Should they place one Modified Mason-Allen, two mattress or four simple sutures? This study reverses current thought. In an in-vitro biomechanical single pull to failure study we compared the ultimate tensile strength of simple, mattress and grasping sutures passed with an arthroscopic suture passer (Surgical Solutions Express-Sew). The aim was to determine which suture configurations would most simply, repeatably and reliably repair the rotator cuff. The ultimate tensile strength and mode of failure of six different suture configurations was repeatedly tested on a validated porcine rotator cuff tendon model, using a standard suture material (Number 2 Fiberwire) passed with the Surgical Solutions Express-sew, in a Hounsfield type H20K-W digital tensometer. Standardising the number of suture passes to four, the strongest construct was two mattress sutures (Mean 169N), followed by single Modified Kessler (Mean 161N), four simple sutures (Mean 155N) and finally a single Mason Allen suture (Mean 140N). Suture configurations involving two passes were all weaker than those with four (one way analysis of variance p=0.026), even when Number 2 Fibertape was used to augment strength. These results show little difference in strength for varying complexity of four pass suture passage (one way analysis of variance p=0.61). In simple terms there is no demonstrable difference in the strength of construct whether the surgeon uses four simple, two mattress or one grasping suture. This study allows the surgeon to justify using the simplest configuration of suture passage that works in his hands in order to obtain a reliable and repeatable repair of the rotator cuff arthroscopically

Introduction: Antegrade intramedullary locked nailing is a reliable method for the treatment of humeral shaft fractures. There is a still debate on the functional effect due to a possible damage during surgical approach of the rotator cuff, but in the Literature few paper deal with the analysis of tendons in these patients. Ultrasonography is still considered a reliable method in evaluating rotator cuff tendons. The aim of this study is to evaluate if antegrade intramedullary nailing may induce a possible damage on rotator cuff. Methods: Between May 2002 to December 2005 42 patient suffering of humeral shaft fractures were surgically treated with Unreamed Humeral Nail. Of them 21 (13 males and 8 female) were followed (average follow-up 22,9 months). All the fractures were traumatic except 1 due to bone metastasis of carcinoma. Follow up was clinical with Constant Score, radiographic in 3 projection (neutral, internal and external), and ultrasonographic, evaluating tendon of m. Sovraspinosus. Results: Healing of fractures was obtained after 2 month from surgery in all cases; Constant Score’s average was 77,0. Three cases of impingement syndrome due to excessive length of nail were observed, healed after the nail removal. Ultrasonography showed that in 13 cases rotator cuff was normal. In 5 cases we have found a signicative hyperecogen area, related to the scarf. We have never had a damage of tendon in all its tickness. Conclusion: Our study confirms that antegrade intra-medullary nail is a reliable method for the treatment humeral shaft fractures, not adversely influenced shoulder tendons. Damage of rotator cuff observed in few cases is not related to surgical technique, but depends on surgical pitfall with an excessively long nail and then impingement syndrome

Proximal humeral fractures are common and often occur in osteoporotic bone. Suture fixation utilises the rotator cuff tendons as well as bone providing adequate stability and avoids complications associated with metalwork insertion. Surgical exposure was via a delto-pectoral approach with minimal dissection of the fracture site. Initially a 2 suture technique was utilized with heavy ethibond sutures passed through drill holes either side of the bicipital groove; however, because of concerns about varus instability the technique now uses a third suture placed laterally acting as a tension band to prevent varus collapse. Patients with Neer 2 and 3 part fractures treated with suture fixation were assessed clinically (using the Constant score) and radiologically at a mean of 27 months post fracture. To date 24 patients have been studied. The average age of the patients in our series was 70.2. All fractures progressed to union with no cases of radiological avascular necrosis. We had 2 cases of mal-union (-one varus and one valgus-), both with a 2-suture technique. One patient had early loss of fixation; re-exploration was performed with stability conferred by a third lateral suture. Active abduction > 120o was achieved in 9 patients with a mean Constant score of 72 compared to 89 on the un-injured contra-lateral side. We have demonstrated that suture fixation of displaced proximal humeral fractures is an effective alternative to fixation using metalwork. The advantages are that minimal soft tissue stripping of the fracture site is required and the potential problems associated with metalwork insertion into osteoporotic bone are avoided. Following one case of varus mal-union with a 2-suture technique we now routinely use a third suture to act as a lateral tension band

Aim: We hypothesize that anabolic steroid administration enhances matrix remodelling and improves the biomechanical properties of bio-artificially engineered human supraspinatus tendons (BATs). Method: BATs were treated either with nandrolone decanoate (NLS group, n=18), stretching (LNS group, n=18), or both (LS group, n=18). A control group received no treatment (NLNS group, n=18). BATs’ contractility was assessed by daily scanning and two dimensional analysis. Cytoskeletal organization was evaluated microscopically with DAPI and rhodamine phalloidin staining. Matrix metalloproteinase-3 (MMP-3) levels – an indicator of matrix remodelling – were discerned by ELISA assay, and biomechanical properties by load-to-failure testing. Results: The LS group showed greatest contractility and the best-organized actin cytoskeleton when compared to the other groups. On the second and third day of treatment, MMP-3 levels in the LS group were significantly greater than those of NLNS group and greater than NLS and LNS groups. The biomechanical properties (load to failure, ultimate stress, ultimate strain, elastic modulus, and energy to failure) in the LS group were significantly improved when compared to NLNS and NLS (p< .05) groups and 26–48% greater than those in LNS group. Conclusions: Nandrolone decanoate and load act synergistically to increase matrix remodelling and biomechanical properties of bioengineered human supraspinatus tendons. Carefully prescribed and monitored, anabolic steroids may have an important adjunct role in postoperative healing and rehabilitation of repaired rotator cuff tendons. More research is necessary to fully evaluate the safety and efficacy of anabolic steroids in this application

Given that there is limited time available to the surgeon in arthroscopic rotator cuff repair, how is the time best spent? Should he place one Modified Mason-Allen, two mattress or four simple sutures? This study reverses current thought. In an in-vitro biomechanical single pull to failure study we compared the ultimate tensile strength of simple, mattress and grasping sutures passed with an arthroscopic suture passer (Surgical Solutions Express-Sew). The aim was to determine which suture configurations would most simply, repeatably and reliably repair the rotator cuff. The ultimate tensile strength and mode of failure of six different suture configurations was repeatedly tested on a validated porcine rotator cuff tendon model, using a standard suture material (Number 2 Fiberwire) passed with the Surgical Solutions Express-sew, in a Hounsfield type H20K-W digital tensometer. Standardising the number of suture passes to four, the strongest construct was two mattress sutures (Mean 169N), followed by single Modified Kessler (Mean 161N), four simple sutures (Mean 155N) and finally a single Mason Allen suture (Mean 140N). Suture configurations involving two passes were all weaker than those with four (one way analysis of variance p=0.026), even when Number 2 Fibertape was used to augment strength. These results show little difference in strength for varying complexity of four pass suture passage (one way analysis of variance p=0.61). In simple terms there is no demonstrable difference in the strength of construct whether the surgeon uses four simple, two mattress or one grasping suture. This study allows the surgeon to justify using the simplest configuration of suture passage that works in his hands in order to obtain a reliable and repeatable repair of the rotator cuff arthroscopically

Aim: The common cause for recurrent instability in older patients, is the massive tear of the rotator cuff tendons. This paper presents the results of the operative treatment for the above-mentioned rare and complex lesion. Method: Seven (7) patients, three (3) male and four (4) female with a mean age of 71 years developed recurrent shoulder instability as a result of trauma or preceding infection, which destroyed the rotator cuff. All cases presented with instability, pain and weakness, and in 2 cases the subluxation was obvious in every attempt to raise the arm. All of the patients had tears in at least two tendons of the rotator cuff. The cases were treated operatively with a combination of the Boytchev anterior stabilization procedure with an attempt to close the rotator cuff tear. A complete closure was achieved in 3 cases, and a partial closure in 2. In the remaining 2 cases the closure of the tear was impossible. All of the patients postoperatively underwent an early mobilization regime. Results: The mean follow-up was 30 months. Stabilization of the shoulder was achieved in 6 cases. Constant score varied from 50 to 85. One patient had a recurrent of the subluxation. All of the patients presented marked improvement in pain and in muscle strength. Two (2) of them developed almost full range of motion and satisfactory muscle strength. Four (4) patients presented decreased range of motion and muscle strength 50% of the unaffected arm, while one patient developed inability to raise his arm above 70 degrees. Conclusions: The combination of recurrent anterior instability with massive rotator cuff tears presents great difþculty in treatment especially in the cases where an infection had preceded. A complete closure of the rotator cuff tear is usually very difþcult to achieve

Surgical repair of rotator cuff tendon is one of the most common orthopaedic procedures performed in the United States. This prospective single-surgeon study reports the long-term results of chronic rotator cuff repair. Vigorous statistical analysis was carried out to detect any association of various outcome parameters with the exact surgical pathology. 105 consecutive shoulders (97 patients) undergoing open repair of chronic (> 3 months) rotator cuff tear between 1975 to 1983 by the senior author were recruited to the study. Pain unresponsive to nonoperative treatment was the indication for surgery. The details of patient’s medical records, radiographic data, and the operative findings were prospectively reviewed. There were 67 males and 30 females with a mean age of 58 years (range, 38 to 75). Follow-up averaged 11 years with no patients lost to follow-up. There were 16 small, 40 medium, 38 large and 11 massive tears. Surgical repair relieved pain in 92% of patients (p< 0.0001). There was also a significant improvement in range of motion (p< 0.0001) and strength of abduction and external rotation following surgery (p< 0.0001). Return of movement and strength decreased with increasing tear size. At the latest follow-up results were rated as excellent in 68 shoulders, satisfactory in 12, and unsatisfactory in 25. 8 out of the 11 massive tears had unsatisfactory outcome. There were eight reoperations for traumatic retears. Standard tendon repair techniques combined with adequate postoperative protection and monitored physical therapy produced consistently satisfactory results. Introduction of experimental repair methods should be confined to those patients with massive tendon tears and only then with the hope of increasing function, as pain relief is satisfactory with usual treatment methods

Purpose: Primary bone tumours located in the upper limb are mainly found in the proximal portion of the humerus. Tumour resection raises difficult situations due to the sacrifice of the cuff tendons. We propose a decision making scheme for determining the best reconstruction strategy. Material and methods: This retrospective analysis was based on 35 cases (19 massive prostheses, ten composite prostheses, three inverted prostheses and three composite arthrodeses). All the clinical and radiographic data were reviewed to examine function, active motion, pain, and use of the upper limb in everyday activities. Results: Massive humeral prostheses provided a technically simple solution but produced mediocre functional results: painless shoulder without active motion, but preservation of elbow and forearm function. Composite humeral prostheses (prosthesis + allograft) did not, in our experience provide any gain in function compared with massive prostheses. Allografts were resorbed after four to five years. Composite arthrodesis with allograft and vascularised fibular graft provided a mobile shoulder with a useful amplitude and a pain free joint. Results persisted. The inverted Delta prostheses (Grammont) covered with allografts and with preservation of the rotator cuff tendons offered an interesting alternative with functional results superior to arthrodesis and similar to those with shoulder prostheses implanted for degenerative disease. The persistence of the glenoid anchorage remains uncertain. Conclusions: We use the following scheme for reconstruction of the proximal humerus. Resection of the proximal humerus with preservation of the deltoid in patients in good general health: inverted composite prosthesis. Resection of the proximal humerus without preservation of the deltoid in patients in poor general health: composite arthrodesis. Resection of the proximal humerus in patients in very poor general health when complex surgery with long post-operative care is not possible: massive prosthesis

Background: Recent studies of arthroscopic rotator cuff repairs have shown high failure. The different suture configurations were mostly tested in non degenerative animal tendon specimen. We used instead fresh-frozen degenerative human cadaver rotator cuffs. The goal of this study was to determine the biomechanical properties of commonly used arthroscopic stitches in ruptured human cuffs in comparison to intact rotator cuffs. Method: 36 human rotator cuff tendons were harvested, documented according to size, thickness and location of rupture, and divided into a ruptured and non ruptured specimen group. We found 12 ruptured and 24 intact cuffs. Three stitch configurations (simple, horizontal, and massive cuff stitch) with a Fiber Wire 2 (Arthrex) were randomized and biomechanically tested in each set of tendon specimen. The specimen were mounted on a uniaxial load machine (ZM200, Fa Shokoohi) and loaded to failure under displacement control at a rate of 0.6 mm/sec. Ultimate tensile load, and type of failure were recorded. Results: Ultimate tensile load was significantly higher (p < 0.05) for the massive cuff stitch (186 ± 12 N) than it was for either the simple stitch (102 ± 9 N) or the horizontal stitch (138 ± 10 N) in the intact cuff cohort. In the ruptured cuff group ultimate tensile load was significantly lower (p < 0.05) for the massive cuff stitch (115 ± 12 N), the simple stitch (77 ± 9 N), and the horizontal stitch (103 ± 10 N) in comparison to the intact cuff group. The simple and horizontal stitches failed by tissue pull-out in both groups, whereas the massive cuff failed by pull-out and once by suture breakage in the group of intact cuffs. Conclusion: Ruptured rotator cuffs showed significant less biomechanical strength concerning all three stitches in comparison to the intact cuff group. Overall the massive cuff stitch showed superior ultimate tensile load

Introduction: The pathogenesis of chronic tendinopathy is unclear. A role for increased apoptosis of tenocytes has been suggested. Nitric oxide is thought to be a mediator of apoptosis and nitric oxide synthase (NOS) isoforms have been shown to be up regulated in rotator cuff tendons as a result of chronic overuse. We found, the same up regulation of NOS in the Achilles tendon in non-insertional Achilles tendinopathy in a previous study. The purpose of this study was to investigate whether apoptotic cells were present in these tissues with raised endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) levels. Methods: Consent was obtained preoperatively from all patients and the research and ethics committee granted ethical approval. Samples were obtained from the Achilles Tendons of patients with non-insertional Achilles tendinopathy who had failed conservative treatment for at least six months and were undergoing a surgical procedure. Several biopsies were taken of the visibly abnormal tendon tissue. Control samples were taken from macroscopically normal tendon correlating with areas of normal tissue on MRI. Standard immunohistochemical techniques were used to identify the expression of eNOS and iNOS. Apoptotic cells were identified using terminal deoxynucleotidyl transferase-mediated dUTP neck end labelling (TUNEL reaction) with TdT-FragEL and the demonstration of Caspase-3 activation. Results: Significant differences were found between the diseased tendon and the controls for all of the parameters measured. The mean Caspase-3 cell count for diseased tendon was 51.9 compared to 28.3 for the controls (p=0.000001). The mean TUNEL cell count for diseased tendon was 24.1 compared to 14.8 (p=0.00014). iNOS densitometry revealed a mean of 26.1 for the diseased tissue verses 15.0 for the controls (p=0.000009) and the values for eNOS were 48.3 and 23.7 respectively (p=0.015). Conclusions: Apoptosis clearly plays a role in the development of non-insertional Achilles tendinopathy and appears to be related to the presence of raised eNOS and iNOS levels. It is possible that, by blocking the apoptotic pathway, the tendinopathic process could be halted. This may lead to the development of treatments strategies for early Achilles tendinopathy

Purpose of the study: Arthroscopic repair of rotator cuff tendons is a well-described technique. Clinical outcome is good. The purpose of this work was to assess tendon healing as observed with the arthroscan after arthroscopic repair of rotator cuff tears. We search for epidemiological, anatomic, and technical factors predictive of healing. Material and methods: This was a prospective consecutive non-randomized series of 167 shoulders. All patients were assessed preoperatively with the Constant clinical score and had a standard imaging protocol for assessing the status of the rotator cuff. Arthroscopic repair was used in all cases. Outcome was assessed with the Constant score and an arthroscan was available for 148 patients. Results: Mean patient age was 59 years, 49% male and 77% dominant side. Mean duration of symptoms before repair was nine months. The tear resulted from trauma in 28% and was a work accident in 9%. The preoperative functional assessment was 52.48. An isolated supraspinatus tear was observed in 68% of the shoulders. Frontal retraction of the supraspinatus was distal in 74%. For 29 shoulders, reduction was difficult and the quality of the tendon was considered normal in 56. Non-anatomic repair was required in six cases. The Constant score at last follow-up (19 months) was 80. An arthroscan was available for 148 shoulders: healing was anatomic in 69, defective healing was observed in 27 and repeated tears were noted in 52. Factors predictive of healing were: demographic (lesion duration less than six months, non-dominant side, young patient, female gender, sedentary lifestyle); anatomic (isolated lesion of the supraspinatus with little extension and no retraction); technical (normal easily reduced tendon, good quality bone). Discussion: The time before surgical management of rotator cuff tears was an important factor in this study. Tendon and muscle alterations after rotator cuff tears could explain, at least in part, healing failures. Conclusion: This study confirmed the good functional and anatomic results obtained with arthroscopic repair of rotator cuff tears

There is more than one option for proximal humerus reconstruction after oncological resection but we believe osteochondral allografts provide a good biological solution for these defects. We report three cases with different histological diagnoses and different results following such reconstruction. The aim is to highlight the advantages and disadvantages of this surgical procedure. The first case report concerns a 15-year-old boy (M.P.) with Ewing’s sarcoma of the proximal humerus. The gleno-humeral articulation and most of the rotator cuff were not involved by the disease. An allograft was used for the reconstruction after satisfactory resection. This allowed good restoration of the function quickly. At 12 months there was a fatigue fracture in the allograft, which required revision with a modular prosthesis. In another patient, a young woman (E.C.), a proximal humeral defect was reconstructed following resection of a benign lesion, fibrous dysplasia. She does not have complete restoration of function but there are no complications at 3 year follow up. The last case is a 49-year-old woman (M.M.), who had osteochondral allograft reconstruction of the proximal humerus after resection of a completely destroyed head by a giant cell tumour. She had good initial results but required revision surgery with Kuntscher nail and vancomycin was added to the cement due to infection. The biological articular reconstruction after oncological wide resection allows good functional results when rotator cuff tendons are available and allografts permit a good and fitting reinsertion. The reported early restoration of function in the young boy (case 1) has to be considered in the stress-fracture genesis. The authors consider that the lack of motion in case 2 was due to a non-aggressive and careful rehabilitation: a quite poor functional result to avoid complications. The case 3 failure is due to an infection, one of most frequent complications in allograft implants. The choice of using an osteochondral allograft must be considered as a useful alternative with prosthetic replacements

Purpose: Appropriate treatment of full-thickness tears of the rotator cuff with subacromial impingement remains a subject of debate. Considering that in most patients, spontaneous tears of the long biceps tendon reduces the pain and that subacromial osteoarthritis is well tolerated by many patients, we proposed arthroscopic tenotomy of the long biceps in this indication with the aim of relieving pain. We report here the long-term outcome. Material and methods: Between 1988 and 1999, 307 arthroscopic tenotomies of the long biceps tendon were performed in patients with unrepairable tears of the rotator cuff tendons (massive full thickness tears, old patients, non-motivated patients). The procedure was isolated in 64% and associated with acromioplasty in 36%. All patients were given prior medical treatment. Mean age at surgery was 64.3 years. The preoperative subacromial height was 6.6 mm. The tendon lesion was an isolated tear of the supraspinatus in 31%, tears of two tendons in 44.6% and tears of three tendons in 21.8%, and isolated tears of the subscapularis in 2.6%. Mean follow-up was 57 months (24–168). Results: The Constant score improved from 48.4 to 67.6 points (p< 0.001). Glenohumeral osteoarthritis (Samilson) increased from 38% to 67% of the shoulders postoperatively. Association with acromioplasty improved the objective and subjective result solely in the group of isolated tears of the supraspinatus. The size of the tear and the degree of fatty degeneration of the rotator cuff muscles had a statistically significant influence on functional and radiographic outcome (p< 0.001) while time since surgery had no effect on radiographic outcome (p< 0.001). Discussion: This simple easy-to-perform procedure yielded pain relief at rest and also nighttime pain. It can be recommended for massive rotator cuff tears with sub-acromial impingement in elderly or poorly-motivated patients whose pain fails to respond to medical treatment. This procedure does not allow recovery of shoulder motion or force

Introduction Ultrasound is a readily available and widely used tool in the investigation of rotator cuff pathology in the shoulder. Reports in the literature as to the diagnostic accuracy of ultrasound in diagnosing cuff tears vary widely. Accuracy rates varying from 50% to 100% have been reported. Most reports reflect the accuracy rates from a single sub-specialized institution. Method Sity-one consecutive patients with rotator cuff pathology diagnosed on ultrasound, underwent arthroscopy of the shoulder and rotator cuff repair, if a full thickness tear was found at surgery. Most patients had their ultrasound ordered by the referring doctor, prior to my initial review. The ultrasounds were performed at various suburban practices. Most were performed at branch practices of one of the three ‘corporate’ practices in Sydney. All full thickness tears were repaired arthroscopically. Results Ultrasound correctly identified rotator cuff tears in 80.3%. Four of 61 patients (6.6%) were reported as having partial thickness tears and at surgery were found to have small full-thickness tears. Six of 61 patients (9.8%) had small full thickness tears diagnosed on ultrasound, but were found to have partial thickness tears at surgery. One patient (1.6%) had an ultrasound diagnosis of a tear but had an intact tendon at surgery. One patient (1.6%) was found to have a full thickness tear with an ultrasound that reported an intact tendon. Conclusions Ultrasound is a valuable tool on the investigation of patients with rotator cuff pathology. It is not reliable in differentiating partial thickness from small full thickness cuff tears. This differentiation is not critical and should not significantly change the patient’s treatment. Reasons for false positive and false negative ultrasounds will be given. Ultrasound for the diagnosis of rotator cuff tendon tears, as performed in suburban practices, is accurate in up to 97% of cases

Aim: We hypothesized that anabolic steroid, combined with substrate strain upregulates expression of gap junction protein Connexin 43 (Cnx43) and increases cell-to-cell communication in human supraspinatus tendon cells. Methods: Human supraspinatus cells were isolated and cultured in nutrient media arranged into 4 groups: 1) non-load, non-steroid (NLNS, n=12); 2) non-load, steroid (NLS, n=12); 3) load, non-steroid (LNS, n=12); and 4) load, steroid (LS, n=12). Steroid and load groups were cultured in 100Nm nandrolone decanoate and loaded at 1% elongation daily for 5 days, respectively. On day five of treatment, cells examined for immunocytochemistry. Cells were also subjected to mechanical stimulation by micro-pipette indentation and the intracellular calcium concentration ([Ca2+]ic) was quantitated using fluorescence microscopy. Numerous parameters were calculated: a) mean average response to stimulation, b) mean peak [Ca2+]ic, c) time of Ca2+ wave propagation, d) spontaneously responding cells prior to stimulation, and e) cell oscillation after stimulation (an indicator of cell toxicity). Results: The LS group demonstrated the greatest density of Cnx43 in comparison to the other groups. Also, the LS group cells showed a significantly greater mean peak [Ca2+]ic and a significantly decreased propagation time, compared to the values of the other groups (p< 0.05). Conclusions: Anabolic steroid, when combined with passive stretch, upregulates gap junction protein Cnx 43 and significantly increases calcium signalling in human supraspinatus tendon cells. When carefully prescribed and monitored, anabolic steroids may increase intercellular calcium signalling and may enhance the healing process of deficient rotator cuff tendons. More research will be necessary to fully evaluate the safety and efficacy of anabolic steroids for this application

The practice of rotator cuff repair rapidly moves towards arthroscopic techniques especially for single tendon tears. Although the clinical results are relatively well established, the structural results of open rotator cuff repair and their correlation with the clinical outcome are poorly known. In order to provide a baseline for future studies using other repair techniques, this study was carried out to assess the structural changes in the repaired musculotendinous unit and to correlate these findings with the clinical outcome after rupture and repair of an isolated full thickness single tendon tear of the rotator cuff. To prospectively assess the quality of an open rotator cuff tendon repair technique, to determine how structural changes of rotator cuff muscles are affected by tendon repair, and to correlate the structural results of MRI studies with the clinical outcome. Direct open repair of a complete, isolated single tendon tear of the rotator cuff resulted in significant improvement in function and objective evidence of tendon healing on MRI. Successful direct repair was not associated with recovery of preoperative muscular atrophy or fatty infiltration when comparing Goutallier stage fatty infiltration between pre and postoperative patients. The age and gender-adjusted Constant score increased significantly from an average of 63.9% preoperatively to 94.5% postoperatively (p< 0.0001). Pain improved significantly from 6.8 points to 13.2 points on a visual analogue scale. (p< 0.0001). Activities of daily living increased from 11.2 points preoperatively to 17.9 points postoperatively (p< 0.0001). Anterior elevation, abduction and internal rotation improved significantly for subscapularis and supraspinatus repairs, but there was no significant change in external rotation. The overall rerupture rate was 12.5%. There was no significant improvement or recovery of muscular atrophy or fatty infiltration after tendon repair. Thirty-two consecutive open repairs of a single tendon tear of the rotator cuff were analysed. The supraspinatus tendon was involved in twenty-two patients and the subscapularis tendon in ten patients. All tendons were repaired using an open technique, a modified Mason-Allen suturing technique, and transosseus fixation with non-absorbable suture material knotted over a bone augmentation device

Introduction: The pathogenesis of chronic tendinopathy is unclear. The role of the increased apoptosis of tenocytes has been suggested by high intratendinous levels of glutamate being demonstrated in patients with tendinosis. Nitric oxide is a known mediator of apoptosis and nitric oxide synthase (NOS) isoforms have been shown to be upregulated in rotator cuff tendons as a result of chronic overuse. We found, the same upregulation of NOS in the Achilles tendon in non-insertional Achilles tendinopathy in a previous study. The purpose of this study was to investigate whether apoptotic cells were present in these tissues with raised eNOS and iNOS levels. Methods: Samples were obtained from the Achilles Tendons of patients with in non-insertional Achilles tendinopathy who had failed conservative treatment for at least six months and were undergoing a surgical procedure. Consent was obtained preoperatively from all patients and ethical approval was granted by the research ethics committee. Several biopsies were taken of the visibly abnormal tendon tissue. Control samples were taken from macroscopically normal tendon correlating with areas of normal tissue on MRI. Standard immunohistochemical techniques were used to identify the expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS). Apoptotic cells were identified using terminal deoxynucleotidyl transferase-mediated dUTP neck end labelling (TUNEL reaction) with TdT-FragEL and the demonstration of Caspase-3 activation. A power calculation was performed which showed that 14 patients in each group would be required to show a 50% difference between the two groups using a level of significance of 5%. Results: Significant differences were found between the diseased tendon and the controls for all of the parameters measured. The mean Caspase-3 cell count for diseased tendon was 51.9 compared to 28.3 for the controls (p=0.000001). The mean TUNEL cell count for diseased tendon was 24.1 compared to 14.8 (p=0.00014). iNOS densitometry revealed a mean of 26.1 for the diseased tissue verses 15.0 for the controls (p=0.000009) and the values for eNOS were 48.3 and 23.7 respectively (p=0.015). Conclusions: Apoptosis clearly plays a role in the development of non-insertional Achilles tendinopathy and appears to be related to the presence of raised eNOS and iNOS levels. It is possible that, by blocking the apoptotic pathway, the tendinopathic process could be halted. This may lead to the development of treatments strategies for early Achilles tendinopathy

Aim: The purpose of this study was to evaluate the cytokine molecules present in a rat tendinopathy model and in the torn edge of human rotator cuff tendon in an attempt to understand their role in tendon degeneration. Methods: A rat tendon overuse model was used with custom microarrays consisting of 5760 rat oligonucleotide features in duplicate. Seventeen torn supraspinatus tendon and matched intact subscapularis tendon samples were collected from patients undergoing arthroscopic shoulder surgery.Control samples of subscapularis tendon were collected from ten patients undergoing arthroscopic stabilisation surgery.Specimens were analysed for the presence of interleukins 18, 15, 12, 11, 6, 2, macrophage inhibitory factor (MIF), and tumour necrosis factor ƒÑ by semiquantitative RT-PCR and immunohistochemistry. Tendinopathy was assessed on a basic histological scale. Results: Rat Microarray analysis: Upregulation of IL-6, IL-11 and IL18 receptor was noted in the degenerated rat supraspinatus tendon. Downregulation of IL-2 was noted. No other cytokine signal was expressed. Histological analysis: All torn human supraspinatus tendons changes consistent with marked tendinopathy. Matched subscapularis tendon showed appearances of moderate-advanced degenerative change. Cytokine mRNA expression: TNF-£\ mRNA expression was found to be significantly elevated (p< 0.01) in subscapularis tendon compared to torn supraspinatus samples. The expression levels of IL-18, IL-15, IL-6 and MIF was significantly higher in the torn edges of supraspinatus when compared to matched subscapularis tendon and normal control tendon (p< 0.001). Immunohistochemical analysis: Presence of IL-18, IL-15, Il-6, MIF and TNF-£\ was confirmed in all samples of torn supraspinatus tendon. Significantly increased levels of IL-18, IL-15, IL-6 and MIF were found in torn supraspinatus. (p< 0.01) compared to matched and normal subscapularis. Conclusions: Cytokines have been shown to promote the intensive production of reactive O2 metabolites . 1. and are potent agonists of protein kinases . 2. Our finding of significantly increased cytokine levels may suggest that these molecules when expressed during the degenerate and healing phases of tendon injury result in the subsequent production of reactive O2 species and protein kinases. 3. causing tendon damage or failure of the normal reparative process. Our finding of marked tendinopathy in matched subscapularis tendon may also provide a useful human tendinopathy model

Background: Up to one third of adults have been estimated to have rotator cuff tendon (RCT) tears. Larger RCT tears are associated with poorer scores and function, and are more likely to re-rupture after surgical repairs, hence there is a need for earlier identification and treatment. The aim of this study was to identify biomarkers of RCT tear pathologies to aid accurate identification and monitoring of disease progression. FTIR provides unique biochemical fingerprints of tissue specimens. All molecules are excited to higher vibrational states at specific wavelengths, which can be used to identify the chemical composition of tissues. Methods: The chemical composition of 55 formalin-fixed RCTs was measured from patients aged between 20 and 89. RCT tears were classified according to size (Post et al.); 10 each of small, medium, large and massive and 5 partial tears. These torn RCTs were compared to 10 uninjured RCTs. A diamond attenuated total reflectance accessory was used with a FTIR spectrometer to collect spectra for each sample. The spectra were reduced and classified using standard multivariate analysis; principal component analysis (PCA), partial least square (PLS) and discriminant function analysis (DFA). Data pre-processing was applied to ensure accurate quantitative data analysis. Results: Hierarchical cluster (HCA) demonstrated that normal and torn tendons could be clearly differentiated, and RCT could also be distinguished by their tear size. Partial tears were clearly distinguishable from normal RCT. Using a genetic algorithm we identified the following spectral regions of importance which accounted for most of the features which discriminated between normal and torn tendons:. 1030–1200cm-1: carbohydrates, phospholipids,. 1300–1700, 3000–3350cm-1: collagen structural conformation and. 2800–3000 cm-1: lipids. Partial tears were distinguishable from other stages of tendon pathology based on a spectral region which correlated with collagen III. Conclusions: FTIR can clearly distinguish normal and different sized RCT tears. This prospective non-randomized study indicates that the onset of RCT tear pathology is mainly due to an alteration of the collagen structural arrangements, with associated changes in lipids and carbohydrates. Partial tears show early onset of chemical changes, particularly in collagen III, which could be used to identify earlier stages of disease. The approach described is rapid and has the potential to be used per-operatively to determine the quality of the tendon and extent of disease, thus guiding surgical repairs or allowing monitoring of disease progression or response to treatments

Aims

The outcomes following nonoperative management of minimally displaced greater tuberosity (GT) fractures, and the factors which influence patient experience, remain poorly defined. We assessed the early patient-derived outcomes following these injuries and examined the effect of a range of demographic- and injury-related variables on these outcomes.

Rotator cuff tears are common in middle-aged and elderly patients. Despite advances in the surgical repair of rotator cuff tears, the rates of recurrent tear remain high. This may be due to the complexity of the tendons of the rotator cuff, which contributes to an inherently hostile healing environment. During the past 20 years, there has been an increased interest in the use of biologics to complement the healing environment in the shoulder, in order to improve rotator cuff healing and reduce the rate of recurrent tears. The aim of this review is to provide a summary of the current evidence for the use of forms of biological augmentation when repairing rotator cuff tears.

Cite this article: Bone Joint J 2024;106-B(9):978–985.

Objective: The high incidence of retear following primary rotator cuff tendon (RCT) repair necessitates new strategies for tendon footprint augmentation. This study’s objective was to evaluate the SeriCuff™, a non-mammalian derived silk-based long-term bioresorbable implant, for RCT footprint reinforcement. The study aimed to characterize the device when overlaid on the infraspinatus tendon footprint of sheep in a RCT repair model. The technique was not targeted for the repair of massive RCT defects but advocated as a preventive measure to cuff reruptures in mid-to-large cuff tears, avoiding the need for surgical revision. Methods: Bilateral surgeries were performed on each of 10 sheep during a single surgical session. The right shoulder of each animal was implanted with SeriCuff and the left shoulder was used as an operated control. The superficial layer of the infraspinatus tendon was removed and feathered for a distance of 1 cm. The remaining footprint was bluntly dissected from the humeral head with the exception of a thin band of the superior portion of the infraspinatus tendon. The footprint was approximated, 3 suture anchors placed equi-distantly along the edge of the full thickness region of the tendon and the tendon sutured to the anchors with a modified Mason-Allen stitch. Two additional anchors were placed along the lateral edge of the tendon in the right shoulder. The SeriCuff device was positioned over the 5 anchors and sutured in place using a single suture at each location (Fig 1B). In the left shoulder, no device was implanted and a second row of anchors was not used. Animals were allowed to ambulate immediately post-op with unrestrained motion for the duration of the study. All animals were necropsied at 3 mos and evaluated histologically (N=4) and mechanically (N=6). Samples designated for mechanical analysis were dissected leaving only the infraspinatus tendon and muscle attached to the humorous. The tendon was pulled to failure at a rate of 500 mm/min with the sample positioned such that the longitudinal axis of the tendon was collinear with the applied load. Results: The animals were able to ambulate following surgery with return to normal gait at an average of 6 days post-operatively. Pain scores diminished with time throughout the first two weeks. Mechanical analysis indicated an average 42% increase in repair strength of the SeriCuff reinforced repair as compared to the contralateral control at 3 months. The SeriCuff device supported the formation of Sharpy’s fibers in the remodeling tendon tissue. Conclusions: The addition of SeriCuff helped to reestablish the tendon footprint resulting in significantly increased repair strength 3 most post-op and therefore may have applications in reducing the high incidence of primary repair failure

Introduction: In many cases of massive rotator cuff tears, especially in cases of revision repairs the shoulder surgeon is facing a technical and biological challenge. The loss of collagenous material in the tendon, coupled with poor quality of the remaining rotator cuff, makes obtaining a mechanically strong repair difficult. Primary closure of such defects may result in excessive tissue tension, which may further increase the chance of failure. Purpose: The objective of this study is to determine the feasibility of using xenogeneic small intestine submucosa (SIS) as a biomaterial to reinforce repair of massive rotator cuff tears. Clinical Material and Methods: Nine patients ranging in age from 52 to 74 with massive rotator cuff tears were selected for the study. Selection of these patients was based upon the quality of remaining rotator cuff tendon tissue at the time of the repair. Seven cases after failed repair of massive rotator cuff tear and two cases of long standing neglected rotator cuff tears in patients with weight bearing shoulders (bilateral below the knees amputation and incomplete paraplegia after anterior poliomyelitis) were selected for this study. In all patients first the tear was repaired by well-known techniques: tendon to tendon, tendon to bone through bone tunnels or using suture anchors. After the repair was accomplished, the poor quality tissue obtained was reinforced by a patch of Restore Orthobiologic Soft Tissue Implant (DePuy, Johnson & Johnson). The Restore Implant is a xenograft obtained of ten layers of porcine small intestine submucosa, it is biocompatible, infection resistant, possess predictable mechanical properties, and, perhaps most significantly, induce a host connective and epithelial tissue response that results in regeneration of specialized connective tissues. Results: Follow-up ranging between 6 to 22 month excellent and good results were observed in eight cases (88%), whereas in the patient aged 74, the cuff repair failed again (after two previous failures). In the eight successful cases an almost normal painfree active range of movements was observed three month after surgery. Conclusions: The results confirm the usefulness of the SIS graft material in the patients having questionable quality cuff tissue remaining after repair. Use of the Restore soft tissue implant could possibly be utilized to strengthen the repair, as well as the inside ingrowth of the tendon, leading to a successful repair of the rotator cuff

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The primary aim of this study was to assess the feasibility of recruiting and retaining patients to a patient-blinded randomized controlled trial comparing corticosteroid injection (CSI) to autologous protein solution (APS) injection for the treatment of subacromial shoulder pain in a community care setting. The study focused on recruitment rates and retention of participants throughout, and collected data on the interventions’ safety and efficacy.

Aim: The common anatomic pathology responsible for the recurrent dislocation of the shoulder is in younger patients a trauma causes the Bankart lesion. Contrary to that, the common cause for recurrent instability in older patients, which is far more rare, is the massive tear of the rotator cuff tendons. During that the shoulder loose the of the posterior-upper stabilizing element (posterior mechanism according to Neer), and present a secondary anterior-inferior recurrent instability. This paper presents the results of the operative treatment for the above-mentioned rare and complex lesion. Material – Method: Seven (7) patients, three (3) male and four (4) female with a mean age of 71 years developed recurrent shoulder instability as a result of trauma or preceding infection, which destroyed the rotator cuff. The initial injury was associated with dislocation in 2 cases and without dislocation in 3. The other 2 had a prior infection of the glenohumeral joint, which was treated conservatively. The patients who suffered injury were initially treated with a sling for 2 to 4 weeks. All cases presented with instability, pain and weakness, and in 2 cases the subluxation was obvious in every attempt to raise the arm. The radiological findings consisted of subacromial space narrowing, sclerosis and spur formation of the inferior part of the acromion and diffuse osteoporosis. All of the patients had tears in at least two tendons of the rotator cuff. The cases were treated operatively with a combination of the Boytchev anterior stabilization procedure (osteotomy of the coracoid process, transfer of the conjoined tendon under the subscapularis tendon and repositioning of the coracoid process) with an attempt to close the rotator cuff tear. A complete closure was achieved in 3 cases (in one the long head of the biceps was used), and a partial closure in 2. In the remaining 2 cases the closure of the tear was impossible. All of the patients postoperatively underwent an early mobilization regime. Results: The mean follow-up was 30 months. Stabilization of the shoulder was achieved in 6 cases. Constant score varied from 50 to 85. One patient had a recurrent of the subluxation. All of the patients presented marked improvement in pain and in muscle strength. Two (2) of them developed almost full range of motion and satisfactory muscle strength. Four (4) patients presented decreased range of motion and muscle strength 50% of the unaffected arm, while one patient developed inability to raise his arm above 70 degrees. Five cases out of seven showed a satisfactory response to daily life activities. Conclusions: The combination of recurrent anterior instability with massive rotator cuff tears presents great difficulty in treatment especially in the cases where an infection had preceded. A complete closure of the rotator cuff tear is usually very difficult to achieve, while the treatment of the instability alone leads to dubious results as far as pain and range of motion is concerned. For the management of the above complex lesion the existing literature is rather poor, and the combination of the Boytchev procedure with an repair of the rotator cuff tear, yielded satisfactory results mainly in regard to pain control, and secondly in achieving a good postoperative range of motion

Improved understanding of the biomechanics and biology of rotator cuff tendons (RCT) may help reduce high re-rupture rates following repairs, particularly amongst larger tears. This study aims to use novel methods for quantitatively determining differences in the mechanical and thermal properties of intact healthy RCTs compared to torn ‘diseased’ tendons. A common problem in the mechanical testing of small tendon samples is that stress risers at the clamp-tendon interface can obscure measurements. As the shoulder is subject to shear, tension and compression, we developed a novel solution using Dynamic Shear Analysis (DSA), a form of rheology which studies material deformation. As collagen is the main component of RCT, the structure and mechanical properties may be affected by collagen conformational changes. Both dermis and rat tail tendon with increased collagen cross-linking exhibit stronger mechanical properties. Thermal changes detected by differential scanning calorimetry (DSC) can help to quantify collagen structural differences in torn RCT, and has been previously used to study muscle, cartilage and vertebral discs. There were 79 tears (mean age 65.2 years), which were classified according to the size of the tear as small, medium, large and massive. Two separate 3mm-sized biopsy samples were taken and subjected to DSA using oscillatory deformation under compression. The storage modulus (G') was calculated and used as an indicator of mechanical integrity. 18 control tendon specimens were obtained from patients aged between 22-89 years (mean age 58.8 years) during shoulder hemiarthroplasties and stabilisations. Additionally 7 normal, 7 small and 7 massive frozen specimens were thermally characterized. 3 samples per patient were heated between 20-80oC in hermetically sealed vessels. Useful thermal parameters were measured such as the melting temperature (TM) which apparently represents breaking of the amide-amide bonds and protein chains mobility, the denaturation temperature (TD) which supposedly corresponds to proteins falling out of solution and the denaturation enthalpy (ΔH) which reflects the relative amount of triple helical structure. Healthy tendons had a significantly higher modulus than torn tendons, indicating that torn tendons are mechanically weaker than normal tendons (p = 0.032). Normal tendons had significantly higher mean shear modulus than tendons with small and massive tears (p<0.01). Overall there was a negative correlation between moduli and severity of tendon tear (r = −0.698, p=0.189). The moduli did not significantly correlate with age, sex, hand dominance, or length of preservation in formalin. Massive RCT tears had significantly higher TM and TD when compared to normal RCT (p < 0.05), unlike small RCT tears. No significant difference was detected between the denaturation enthalpy of the different RCT groups. This case control study has demonstrated that normal RCTs have a significantly higher modulus than torn tendons, indicating that torn tendons have less mechanical integrity. Our study further demonstrated a trend between increasing tear size and decreasing mechanical integrity. This study has also demonstrated differences in some of the thermal properties of normal and torn RCTs. These are likely due to collagen structural changes. A decrease in the denaturation temperature of torn tendons, suggests that the material is intrinsically less stable. Torn tendons with reduced storage modulus and collagen integrity may be less able to withstand mechanical loads following repair. This pilot study provides some preliminary insight into the mechanisms that may contribute to, or represent adaptations to high rates of failure of RCT repairs

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The aim of this study is to provide a detailed description of cases combining bridging patch repair with artificial ligament “internal brace” reinforcement to treat irreparable massive rotator cuff tears, and report the preliminary results.

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The aim of this study was to compare the characteristics and outcomes of L-shaped and reverse L-shaped rotator cuff tears.

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Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures.

Studies have shown that the trees minor plays an important role after total (TSA) and reverse (RSA) shoulder arthroplasty, as well as in maintenance of function in the setting of infraspinatus wasting. In this regard, teres minor hypertrophy has been described as a compensatory change in response to this infraspinatus wasting, and has been suggested that this compensatory hypertrophy may mitigate the loss of infraspinatus function in the patient with a large rotator cuff tear. The purpose of this study was to determine the prevalence of teres minor hypertrophy in a cohort of patients undergoing rotator cuff repair, and to determine its prognostic effect, if any, on outcomes after surgical repair. Over a 3 year period, all rotator cuff repairs performed in a single practice by 3 ASES member surgeons were collected. Inclusion criteria included both preoperative and postoperative validated outcomes measures (minimum 2 year), and preoperative Magnetic Resonance Imaging (MRI) scanning. 144 patients met all criteria. MRIs were evaluated for rotator cuff tear tendon involvement, tear size, and Goutallier changes of each muscle. In addition, occupational ratios were determined for the supraspinatus, infraspinatus, and teres minor muscles. Patients were divided into 2 groups, based upon whether they had teres minor hypertrophy or not, based on a previously established definition. A 2 way ANOVA was used to determine the effect of teres minor hypertrophy(tear size by hypertrophy) and Goutallier. Teres minor hypertrophy was a relatively common finding in this cohort of rotator cuff patients, with 51% of all shoulders demonstrating hypertrophy. Interestingly, in patients without an infraspinatus tear, teres minor hypertrophy was still present in 19/40 (48%) of patients. Teres minor hypertrophy had a significant, negative effect ASES scores after rotator cuff repair in patients with and without infraspinatus tearing, infraspinatus atrophy, and fatty infiltrative changes (P<0.05). In general, the presence of teres minor hypertrophy showed 10–15% less improvement (Figure 1) than when no hypertrophy was present, and this was consistent across all tear sizes, independent of Goutallier changes. Teres minor hypertrophy is a common finding in the setting of rotator cuff tearing, including in the absence of infraspinatus tearing. Contrary to previous publications, the presence of teres minor hypertrophy in patients with rotator cuff repair does not appear to be protective as a compensatory mechanism. While further study is necessary to determine the mechanism or implication of teres minor hypertrophy in setting of rotator cuff repair, our results show it is not a positive of outcomes following rotator cuff repair

The pathology of the RAshoulder differs from that of the OA shoulder. In addition to replacement of the glenohumeral joint, procedures have to be performed to deal with disorders specific for the RA shoulder, such as bone deficiency of the glenoid, thinning or rupture of the rotator cuff, and severe internal rotation defomity. Timing of shoulder arthroplasty in the rheumatoid patient is stilla controversial issue. Clinical symptoms are more important than the radiographic destruction for timing of surgery. The status of the rotator cuff and the glenoid will predict the functional result. Controversial issues ar whether the synovitis of the AC-joint and the subacromial area should be treated arthroscopically early to prevent destruction of the cuff, whether repair of the rotator cuff or tendon transfers effect the end result, and whether replacement of the glenoid is beneficial. The surgical management of advanced destruction of the rheumatoid elbow differs from one center to the next, as controversy exists regarding the success of synovectomy. Total elbow arthroplasty in patients with advanced joint destruction has gained popularity. Controversial issues and new developments will be discussed

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The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts.

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In the context of tendon degenerative disorders, the need for innovative conservative treatments that can improve the intrinsic healing potential of tendon tissue is progressively increasing. In this study, the role of pulsed electromagnetic fields (PEMFs) in improving the tendon healing process was evaluated in a rat model of collagenase-induced Achilles tendinopathy.

Background:. Massive rotator cuff tear can cause functional disability due to instability and degenerative changes of the shoulder joint. In patients with massive irreparable rotator cuff tear, tendon transfer is often used as the salvage procedure. Latissimus dorsi and pectoris major transfer are technically demanding procedures and may incur complications. The biceps tendon transfer may provide a biologically superior tissue patch that improves the biomechanics of the shoulder joint in patients with irreparable rotator cuff tear. This study evaluated the functional outcomes of biceps tendon transfer for irreparable rotator cuff tear in 6 patients with two years and longer follow-up. Methods:. Between September 2006 and October 2011, 50 patients with 50 shoulders underwent surgical repair for MRI confirmed rotator cuff tear. Among them, six patients with massive irreparable rotator cuff tear were identified intraoperatively, and underwent proximal biceps tendon transfer to reconstruct the rotator cuff tear. The biceps tendon was tenodesed at the bicipital groove, and the proximal intra-articular portion of the biceps tendon was transected. The biceps graft was fanned out and the distal end fixed to the cancellous trough around the greater tuberosity with suture anchor. The anterior edge was sutured to the subscapularis and the posterior edge to the infraspinatus tendon or supraspinatus if present. Postoperative managements included sling protection and avoidance of strenuous exercises for 6 weeks, and then progressive rehabilitation until recovery. Results:. The evaluation parameters included VAS pain score, UCLA score, Constant score and AHES score, and X-rays of the shoulder. At follow-up of 25.3 ± 25.0 (range 22 to 63) months, the mean VAS pain score decreased from 9.3 ± 0.8 preoperatively to 1.7 ± 1.4 postoperatively (p < 0.001). All patients presented with significant improvements in pain and function of the shoulder for daily activities after surgery, however, only one patient achieved excellent results. There is no correlation of functional outcome with age, gender and body mass index. There was no infection or neurovascular complication. Discussion:. The biceps transfer provides soft tissue coverage of the humeral head, and restores the superior stability of the shoulder joint. The transferred biceps tendon also improves the mechanics and increases the compression force of the humeral head to the glenoid fossa. The results of the current study showed significant pain relief and improvement of shoulder function after biceps tendon transfer for irreparable rotator cuff tear. Conclusion:. Biceps tendon transfer is effective in the management of massive irreparable rotator cuff tear. The procedure is technically accessible with minimal surgical risks

INTRODUCTION. There is increasing evidence for a multi-stage model of rotator cuff (RC) tendon tears, wherein healing is affected by tear size. The underlying pathophysiology however is not fully understood. Changes in the production and remodeling of the RC extracellular matrix (ECM) are likely to be important determinants of RC tendinopathy as they affect healing and the ability to bear loads. This study aimed to gain greater insight into size related tear pathogenesis by analyzing gene expression profiles from normal, small and massive RC tears. METHODS. The genetic profiles of 28 human RC tendons were analyzed using microarrays representing the entire genome. 11 massive and 5 small torn RC tendon specimens were obtained from tear edges intraoperatively, and compared to 12 age matched normal controls. Semiquantitative real-time polymerase chain reaction (RT-PCR) and immunohistochemistry were performed for validation. RESULTS. Numerous insightful gene changes were detected. Key changes included upregulation of aggrecan in massive tendon tears compared to normal controls, but not in small tears (p < 0.05 and > 2-fold change). Matrix metallopeptidases (MMP)-3,-10,-12,-13,-15,-21,-25 and a disintegrin and metallopeptidase (ADAMs)-12,-15,-22 were significantly upregulated in tears. Aggrecan was upregulated in massive tendon tears but not in small tears. Amyloid was downregulated in the small and massive tear groups when compared to normals. BMP-5 was upregulated in small tears only when compared to normals. As part of the chemotaxis pathway, IL-3,-10,-13,-15,-18 were upregulated in tears, whereas downregulation of IL-1,-8,-11,-27, was seen. RT-PCR and immunohistochemistry confirmed altered gene expression. CONCLUSION. The gene profiles of normal, small and massive RC tear groups suggested they are biologically distinct groups. In addition to confirming altered gene expression in pathways reported in previous studies, this study has identified a number of novel pathways which are affected between the different tendon tear and normal groups. This study identified that RC tear pathogenesis is contributed to by ECM remodeling genes, chemotaxis genes, aggrecan and amyloid. Further investigation is required to determine whether some of these genes may potentially have a role as biomarkers of failure. Modulating these ECM pathways may be a useful treatment strategy for improving clinical outcomes

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Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots.

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The aim of this study was to compare the osseous reactions elicited by all-suture, polyetheretherketone (PEEK), and two different biodegradable anchors used during rotator cuff repair.

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In order to determine whether and for whom serial radiological evaluation is necessary in one-part proximal humerus fractures, we set out to describe the clinical history and predictors of secondary displacement in patients sustaining these injuries.

Objectives

The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue.

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Shoulder arthroplasty using short humeral components is becoming increasingly popular. Some such components have been associated with relatively high rates of adverse radiological findings. The aim of this retrospective review was to evaluate the radiological humeral bone changes and mechanical failure rates with implantation of a short cementless humeral component in anatomical (TSA) and reverse shoulder arthroplasty (RSA).

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Failure of healing is a well-known problem after repair of the rotator cuff. This study aimed to investigate if early repair of trauma-related full-thickness rotator cuff tears (FTRCTs) could prevent this failure.

Objectives

This study evaluated the mechanical performance, under low-load cyclic loading, of two different knotless suture anchor designs: sutures completely internal to the anchor body (SpeedScrew) and sutures external to the anchor body and adjacent to bone (MultiFIX P).

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We present our experience of using a metal-backed prosthesis and autologous bone graft to treat gross glenoid bone deficiency.

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Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically.

The October 2015 Shoulder & Elbow Roundup³⁶⁰ looks at: Culture time important in propionibacterium acnes; Microvascularisation of the cuff footprint; Degenerative cuff tears: evidence for repair; Middle ground in distal humeral fractures?; Haste needed in elbow heterotopic ossification; Iatrogenic frozen shoulder; Salvage of failed humeral fixation

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We conducted a study to identify factors that are prognostic of the outcome of extracorporeal shockwave therapy (ESWT) for calcific tendinitis of the shoulder.

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The aim of the study was to develop a quantitative scoring system to predict whether a large-to-massive rotator cuff tear was arthroscopically reparable prior to surgery.

We hypothesised that a large acromial cover with an upwardly tilted glenoid fossa would be associated with degenerative rotator cuff tears (RCTs), and conversely, that a short acromion with an inferiorly inclined glenoid would be associated with glenohumeral osteoarthritis (OA). This hypothesis was tested using a new radiological parameter, the critical shoulder angle (CSA), which combines the measurements of inclination of the glenoid and the lateral extension of the acromion (the acromion index).

The CSA was measured on standardised radiographs of three groups: 1) a control group of 94 asymptomatic shoulders with normal rotator cuffs and no OA; 2) a group of 102 shoulders with MRI-documented full-thickness RCTs without OA; and 3) a group of 102 shoulders with primary OA and no RCTs noted during total shoulder replacement. The mean CSA was 33.1° (26.8° to 38.6°) in the control group, 38.0° (29.5° to 43.5°) in the RCT group and 28.1° (18.6° to 35.8°) in the OA group. Of patients with a CSA > 35°, 84% were in the RCT group and of those with a CSA < 30°, 93% were in the OA group.

We therefore concluded that primary glenohumeral OA is associated with significantly smaller degenerative RCTs with significantly larger CSAs than asymptomatic shoulders without these pathologies. These findings suggest that individual quantitative anatomy may imply biomechanics that are likely to induce specific types of degenerative joint disorders.

Cite this article: Bone Joint J 2013;95-B:935–41.

Aims

The eccentric glenosphere was principally introduced into reverse shoulder arthroplasty to reduce the incidence of scapular notching. There is only limited information about the influence of its design on deltoid power and joint reaction forces.

The aim of our study was to investigate how the diameter and eccentricity of the glenosphere affect the biomechanics of the deltoid and the resultant joint reaction forces.

This study evaluates the position of the long head of biceps tendon using ultrasound following simple tenotomy, in patients with arthroscopically repaired rotator cuff tears.

In total, 52 patients with a mean age of 60.7 years (45 to 75) underwent arthroscopic repair of the rotator cuff and simple tenotomy of the long head of biceps tendon. At two years post-operatively, ultrasound revealed that the tendon was inside the bicipital groove in 43 patients (82.7%) and outside in nine (17.3%); in six of these it was lying just outside the groove and in the remaining three (5.8%) it was in a remote position with a positive Popeye Sign. A dynamic ultrasound scan revealed that the tenotomised tendons had adhered to the surrounding tissues (autotenodesis).The initial condition of the tendon influenced its final position (p < 0.0005). The presence of a Popeye sign was statistically influenced by the pre-operative co-existence of supraspinatus and subscapularis tears (p < 0.0001).

It appears that the natural history of the tenotomised long head of biceps tendon is to tenodese itself inside or just outside the bicipital groove, while its pre-operative condition and coexistent subscapularis tears play a significant role in the occurrence of a Popeye sign.

The aim of this study was to investigate the occurrence of tissue hypoxia and apoptosis at different stages of tendinopathy and tears of the rotator cuff.

We studied tissue from 24 patients with eight graded stages of either impingement (mild, moderate and severe) or tears of the rotator cuff (partial, small, medium, large and massive) and three controls. Biopsies were analysed using three immunohistochemical techniques, namely antibodies against HIF-1α (a transcription factor produced in a hypoxic environment), BNip3 (a HIF-1α regulated pro-apoptotic protein) and TUNEL (detecting DNA fragmentation in apoptosis).

The HIF-1α expression was greatest in mild impingement and in partial, small, medium and large tears. BNip3 expression increased significantly in partial, small, medium and large tears but was reduced in massive tears. Apoptosis was increased in small, medium, large and massive tears but not in partial tears.

These findings reveal evidence of hypoxic damage throughout the spectrum of pathology of the rotator cuff which may contribute to loss of cells by apoptosis. This provides a novel insight into the causes of degeneration of the rotator cuff and highlights possible options for treatment.

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 supraspinatus tendon was created in 80 rabbits which were separated into two equal groups. A single-row repair with two suture anchors was conducted in group 1 and a double-row repair with four suture anchors in group 2. A total of ten intact contralateral shoulder joints was used as a control group. Biomechanical testing was performed immediately post-operatively and at four and eight weeks, and histological analysis at four and eight weeks.

The mean load to failure in group 2 animals was greater than in group 1, but both groups remained lower than the control group at all intervals. Histological analysis showed similar healing properties at four and eight weeks in both groups, but a significantly larger number of healed tendon-bone interfaces were identified in group 2 than in group 1 at eight weeks (p < 0.012).

The ultimate load to failure increased with the number of suture anchors used immediately post-operatively, and at four and eight weeks. The increased load to failure at eight weeks seemed to be related to the increase in the surface area of healed tendon-to-bone in the double-row repair group.