Rotator Cuff Tendon Tears Research Articles

Partial Infraspinatus Tendon Transection as a Means for the Development of a Translational Ovine Chronic Rotator Cuff Disease Model.

Rotator cuff tendon tears are the most common soft tissue injuries in the shoulder joint. Various animal models have been described for this condition, but all current translational animal models have inherent weaknesses in their ability to generate chronically degenerated rotator cuff tendons. The objective of this study was to evaluate a partial infraspinatus tendon transection model as a means of creating a chronically degenerated rotator cuff tendon in an ovine model and compare the injury characteristics of this model to those observed in human patients with severe chronic rotator cuff tendon injuries. The infraspinatus tendons of six sheep were partially detached followed by capping of the detached medial section of the tendon with Gore-Tex. Human tissue samples of the supraspinatus tendon were harvested from patients undergoing primary reverse shoulder arthroplasty and served as positive controls of chronic rotator cuff tendinopathy. Transected sheep tendons were characterized predominantly by an acute reactive and reparative pathological process as compared with the chronic degenerative changes observed in the human tendons. In contrast, the non-transected portion of the ovine tendon showed histological changes, which were more chronic and degenerative in nature when compared with the transected tendon. Overall, histological features of the non-transected portion of ovine tendon were more similar to those observed in the chronic degenerated human tendon.

Evaluation of animal models and methods for assessing shoulder function after rotator cuff tear: A systematic review.

Background and objectiveRestoring the shoulder function is a crucial demand of patients with rotator cuff (RC) tears. Most preclinical studies only focused on biological and mechanical measurements. Functional assessment was less investigated in the preclinical studies. This study aims to review the literature of shoulder function in animal models for RC tears and evaluate the strengths and weaknesses of different shoulder functional assessments and animal models.MethodA literature search for studies used RC tear animal models to evaluate changes in shoulder function was performed. We searched databases of PubMed, Embase, Web of Science, and Scopus from inception to September 2019. Animal species, functional parameters, injury and repair types, and study durations were summarised. Cluster analyses were then used to separate animal models with different levels of injury and timings of repair. The reliability and clinical relevance of the included assessments and animal models were then discussed.ResultsFourteen animal studies that related to shoulder function in animal models of RC tears were reviewed. Five methods (gait analysis, passive range of motion test, open field test, staircase test, and running endurance test) to assess shoulder function were identified. Single or massive RC tendon tears and immediate or delayed RC repair models were found. We reported and discussed factors to be considered when researchers would select assessments and animal models for different study purposes.ConclusionBased on current evidences, gait analysis is the most appropriate method to assess changes in shoulder function of animal models of RC tears. More studies are required to further elucidate the reliability of passive range of motion measurement, open field test, staircase test, and running endurance test. Models that use massive tears and delayed repair better represent the clinical condition found in humans.The translational potential of this articleUsing more clinically relevant animal models and assessments for shoulder function identified in this review may help to investigate the value of preclinical researches and promote translation of preclinical interventions into clinical practices.

Elasticity of torn supraspinatus tendons measured by shear wave elastography: a potential surrogate marker of chronicity?

PurposeThis study investigated whether shear wave elastography (SWE) could be used to estimate the chronicity of supraspinatus tendon (SST) tears.MethodsA retrospective study was performed. From November 2015 to July 2016, 113 patients (52 men, 61 women; age range, 21 to 79 years) with persistent shoulder pain underwent 119 rotator cuff tendon examinations by routine B-mode ultrasonography, while SST elasticity was measured using SWE. Following the exclusion of eight suboptimal examinations, four examinations with missing SST measurements, and 27 examinations of patients with other conditions, 80 examinations were analyzed. A torn SST was found in 54 examinations (27 with a partial-thickness tear and 27 with a full-thickness tear). Elasticity values were compared in multiple ways. The results were analyzed using the Mann-Whitney U test or Kruskal-Wallis test.ResultsNo statistically significant difference in elasticity values (in kPa) was found between normal (median, 94.65; interquartile range [IQR], 87.43 to 105.47) and torn SSTs (median, 96.79; IQR, 86.71 to 108.56) or between full-thickness tears (median, 93.80; IQR, 82.50 to 108.33) and partial-thickness tears (median, 96.83; IQR, 90.60 to 112.20). However, there was a statistically significant difference in elasticity according to whether the duration of symptoms was 1 year or less (median, 92.20; IQR, 84.01 to 104.38) or longer than 1 year (median, 105.10; IQR, 100.41 to 116.03; P=0.032).ConclusionElasticity values were significantly higher in torn SSTs in patients with chronic shoulder pain that had persisted for more than 1 year. Further studies with larger samples seem warranted to determine whether elasticity values measured by SWE can be used preoperatively as a surrogate marker of the chronicity of a rotator cuff tendon tear.

Synovial cyst of the acromioclavicular joint with and without rotator cuff tear: A case series of two patients

IntroductionAcromioclavicular joint cyst (AJC) is a very uncommon condition of the shoulder observed in elderly patients, caused by a degenerative acromioclavicular (AC) joint, frequently associated to a rotator cuff tendon tear. There are two possible cause for the cyst formation. We report two different cases of a AC synovial cyst, with and without rotator cuff tear. Presentation of casesWe report two cases, in patients aged respectively 80 and 77 years, with a very large AJC. In one case, the cyst was associated to a rotator cuff tear, while in the other case, the rotator cuff did not present any evident lesion. Both cysts were successfully surgical excised and a distal clavicle resection was performed. DiscussionAJC is a rare complication observed in degenerative AC joint and in the majority of cases is associated to a rotator cuff tear. The diagnosis may be made by ultrasound and conventional radiographic examination, although MRI of the shoulder is generally preferred as it allows to better identify the condition of the rotator cuff. Generally, local aspiration of the cyst and corticosteroid injection fails with recurrence of the cyst and surgically treatment is indicated, especially in painful cases. ConclusionPainful AJC should be surgically treated by excision of the cyst associated to a lateral clavicle resection; when a symptomatic massive rotator cuff is present, a reverse total shoulder arthroplasty may be considered. However, in elderly patients, who have no discomfort, watchful waiting may be the treatment of choice.

Beige FAPs Transplantation Improves Muscle Quality and Shoulder Function After Massive Rotator Cuff Tears.

Rotator cuff (RC) tears are a common cause of upper extremity disability. Any tear size can result in subsequent muscle atrophy and fatty infiltration (FI). Preoperative muscle degeneration can predict repair and postoperative functional outcomes. Muscle residential fibro-adipogenic progenitors (FAPs) are found to be capable of differentiating into beige adipocytes that release factors to promote muscle growth. This study evaluated the regenerative potential of local cell transplantation of beige FAPs to mitigate muscle degeneration in a murine massive RC tear model. Beige FAPs were isolated from muscle in UCP-1 reporter mice by flow cytometry as UCP-1+ /Sca1+ /PDGFR+ /CD31- /CD45- /integrin α7- . C57/BL6J mice undergoing supraspinatus tendon tear with suprascapular nerve transection (TT + DN) received either no additional treatment, phosphate-buffered saline injection, or beige FAP injection 2 weeks after the initial injury. Forelimb gait analysis was used to assess shoulder function with DigiGait. Mice were sacrificed 6 weeks after cell transplantation. FI, fibrosis, fiber size, vascularity were analyzed and quantified via ImageJ. Our results showed that beige FAP transplantation significantly decreased fibrosis, FI, and atrophy, enhanced vascularization compared with saline injection and non-treatment groups. Beige FAP transplantation also significantly improved shoulder function as measured by gait analysis. This study suggests that beige-differentiated FAPs may serve as a treatment option for RC muscle atrophy and FI, thus improving shoulder function in patients with massive RC tendon tears. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1159-1166, 2020.

Localized Rotator Cuff Tendon Degeneration for Cadaveric Shoulders with and Without Tears Isolated to the Supraspinatus Tendon.

Localized differences in tissue degeneration throughout intact and torn rotator cuff tendons have not been well quantified. The objective of this study was to investigate histological differences in localized degeneration in tendons with and without rotator cuff tears isolated to the supraspinatus tendon. Four intact shoulders and four shoulders with rotator cuff tears isolated to the supraspinatus tendon were dissected down to the infraspinatus and supraspinatus tendons. Biopsies were taken throughout the tendon insertion, mid-substance, myotendinous junction, and around the tear if present. Samples were stained with hematoxylin and eosin and tendon degeneration was graded based on collagen fiber organization, nuclei shape, cellularity, and lipoid degeneration. Comparisons in degeneration parameters were made based on the tendon type (supraspinatus vs. infraspinatus), location within the tendon, and presence of a tear. Supraspinatus tendons exhibited more degeneration than the infraspinatus tendon (P < 0.05). Significant increases in lipoid degeneration were found near the myotendinous junction compared to the rest of the tendon (P < 0.001). Tendons with rotator cuff tears showed greater amounts of lipoid degeneration compared to intact tendons (P = 0.03). A strong negative correlation was found between lipoid degeneration and collagen fiber organization (r = -0.922, P = 0.001). No differences in degeneration were found between medial, anterior, and posterior edges of the tear. The study highlights specific factors of tendon degeneration contributing to the local differences in tendon degeneration. By understanding local differences in tendon degeneration, surgical protocols for repair can be improved. Clin. Anat., 33:1007-1013, 2020. © 2019 Wiley Periodicals, Inc.

An adaptive two-arm clinical trial using early endpoints to inform decision making: design for a study of sub-acromial spacers for repair of rotator cuff tendon tears

BackgroundThere is widespread concern across the clinical and research communities that clinical trials, powered for patient-reported outcomes, testing new surgical procedures are often expensive and time-consuming, particularly when the new intervention is shown to be no better than the standard. Conventional (non-adaptive) randomised controlled trials (RCTs) are perceived as being particularly inefficient in this setting. Therefore, we have developed an adaptive group sequential design that allows early endpoints to inform decision making and show, through simulations and a worked example, that these designs are feasible and often preferable to conventional non-adaptive designs. The methodology is motivated by an ongoing clinical trial investigating a saline-filled balloon, inserted above the main joint of the shoulder at the end of arthroscopic debridement, for treatment of tears of rotor cuff tendons. This research question and setting is typical of many studies undertaken to assess new surgical procedures.MethodsTest statistics are presented based on the setting of two early outcomes, and methods for estimation of sequential stopping boundaries are described. A framework for the implementation of simulations to evaluate design characteristics is also described.ResultsSimulations show that designs with one, two and three early looks are feasible and, with appropriately chosen futility stopping boundaries, have appealing design characteristics. A number of possible design options are described that have good power and a high probability of stopping for futility if there is no evidence of a treatment effect at early looks. A worked example, with code in R, provides a practical demonstration of how the design might work in a real study.ConclusionsIn summary, we show that adaptive designs are feasible and could work in practice. We describe the operating characteristics of the designs and provide guidelines for appropriate values for the stopping boundaries for the START:REACTS (Sub-acromial spacer for Tears Affecting Rotator cuff Tendons: a Randomised, Efficient, Adaptive Clinical Trial in Surgery) study.Trial registrationISRCTN Registry, ISRCTN17825590. Registered on 5 March 2018.

A high glucose level stimulate inflammation and weaken pro-resolving response in tendon cells – A possible factor contributing to tendinopathy in diabetic patients

BackgroundTendinopathy is a chronic disorder that affects a huge population, and is causing high socioeconomical impacts worldwide. Tendinopathy was reported to be more prevalent in diabetic patients, and chronic inflammation was proposed to play an important role in its development. It was also known that diabetic patients present in a pro-inflammatory state. There is a possibility that the high glucose environment in diabetic patients lead to chronic inflammation in the tendon, and eventually the development of tendinopathy. In this study, we would simulate the diabetic environment in an in vitro setup, to assess the effect of a high glucose level on cultured tendinopathic and healthy tendon derived stem cells (TDSCs) under inflammatory stress. We would first like to assess whether there are differences between the inflammatory response in tendinopathic and healthy TDSCs. We would then investigate whether a high glucose level may lead to changes in the inflammatory response in healthy tendon cells. MethodsTendinopathic TDSCs were cultured from 2 torn rotator cuff tendons and 1 ruptured patellar tendon. Healthy TDSCs were cultured from 3 gender matched healthy hamstring tendons. Cells were stimulated by either 2ng/ml IL-1B for 24 hours, 11.1 mmol/L glucose for 24 hours, or both. mRNA was collected and processed for qPCR targeting B-actin, ALOX12, ALOX15, FPR1, FPR2, ChemR23, and COX2. ResultsUpregulation of FPR1 (p=0.050) ChemR23 (p=0.050), ALOX15 (p=0.050) was significantly weakened when comparing tendinopathic and healthy TDSCs stimulated with IL-1b. The upregulation of ALOX15 (p=0.050), was significantly lower in stimulated healthy TDSCs in a high glucose environment when comparing with those stimulated under a regular glucose level. A high glucose level also induced upregulation of COX2 (p=0.046) in healthy TDSCs and tendinopathic TDSCs (p=0.050). ConclusionThe results of this study provide a possible explanation to the increased risk to develop tendinopathy in diabetic patients. Chronic inflammation observed in tendinopathy may be due to the weakening of pro-resolving responses in tendinopathic TDSCs, and a high glucose environment may lead to chronic inflammation and ultimately tendinopathy by persistent stimulation and weakening of pro-resolving response in healthy TDSCs.

Regenerative effects of mesenchymal stem cells by dosage in a chronic rotator cuff tendon tear in a rabbit model.

Aim: We investigated the therapeutic effects and optimal dose of human umbilical cord blood (UCB)-derived mesenchymal stem cell (MSC) injection in a chronic full-thickness rotator cuff tendon tear. Methods: Rabbits (n=30) were allocated into three groups (normal saline, G1-Sal; 1×106 cells UCB-MSC, G2-Low; 2×106 cells UCB-MSC, G3-High). Injections were done into the chronic full-thickness rotator cuff tendon tear 6weeks after a full-thickness tendon tear of the subscapularis was created. Gross & histologic evaluation and motion analysis was done at pre and 4weeks post-injection. Results: There were no significant differences in tear size and motion analysis parameters 4weeks after injection between G2-Low and G3-High. Conclusion: The benefits of UCB-MSCs are not dose-dependent in a rabbit model.

Synergic regenerative effects of polydeoxyribonucleotide and microcurrent on full-thickness rotator cuff healing in a rabbit model.

Rotator cuff tendon tears (RCTTs) are common adult injuries. We hypothesized that a local injection of polydeoxyribonucleotide (PDRN) and microcurrent therapy (MIC) would be more effective in regenerating a tendon tear than PDRN administration alone. To evaluate the effect of PDRN combined with MIC on the regeneration of RCTTs in a rabbit subscapularis tendon chronic RCTT model. Rabbits (n=24) were allocated to 3 groups at 6 weeks after full-thickness RCTT (FTRCTT): 0.2mL normal saline (G1-SAL); 0.2mL PDRN with Sham MIC (G2-PDRN+Sham MIC); and 0.2mL PDRN with MIC (G3-PDRN+MIC). All treatments were performed under ultrasound guidance. PDRN was injected weekly for 4 weeks and sham MIC or MIC was applied daily for 4 weeks after the first PDRN injection. In the G3-PDRN+MIC group, the mean (SD) subscapularis tendon tear size was continuously reduced from 1 week post-treatment to 4 weeks and was significantly decreased as compared with the other 2 groups [6.0 (1.5) vs. G1: 11.5 (1.8) and G2: 9.1 (1.6) mm2; G3 vs. G1, P<0.001; G3 vs. G2, P=0.018]. The gross morphologic mean tendon tear size was significantly smaller in the G3-PDRN+MIC group than G1-SAL and G2-PDRN+ Sham MIC groups [8.8 (3.5) vs. 15.9 (2.3) and 12.4 (1.6) mm2; G3 vs. G1, P<0.001; G3 vs. G2, P=0.03]. Mean values for regenerated collagen type 1 fibers, angiogenesis, and walking parameters were all greater for the G3-PDRN+MIC group than the other 2 groups based on histological examination and motion analysis [collagen type 1, G3: 1.60 (0.80) vs. G1: 0.45 (0.60), G2: 1.10 (0.74), G3 vs. G1, P<0.001; G3 vs. G2, P=0.002] [angiogenesis, G3: 2.44 (0.73) vs. G1: 0.80 (0.82) and G2: 2.06 (0.81), G3 vs. G1, P<0.001; G3 vs. G2, P=0.006] [walking distance, G3: 6391.4 (196.9) vs. G1: 4852.8 (137.3) and G2: 5514.4 (257.3) cm; G3 vs. G1, P<0.001; G3 vs. G2, P<0.001]. On gross morphologic, histological, and motion analysis, combined PDRN with MIC therapy was more effective than PDRN alone treating a rabbit model of chronic traumatic FTRCTT.

Advanced septic arthritis of the shoulder treated by a two-stage arthroplasty.

BACKGROUNDThe usual treatment of septic shoulder arthritis consists of arthroscopic or open lavage and debridement. However, in patients with advanced osteoarthritic changes and/or massive rotator cuff tendon tears, infection eradication can be challenging to achieve and the functional outcome is often not satisfying even after successful infection eradication. In such cases a two-stage approach with initial resection of the native infected articular surfaces, implantation of a cement spacer before final treatment with a total shoulder arthroplasty in a second stage is gaining popularity in recent years with the data in literature however being still limited.AIMTo evaluate the results of a short interval two-stage arthroplasty approach for septic arthritis with concomitant advanced degenerative changes of the shoulder joint.METHODSWe retrospectively included five consecutive patients over a five-year period and evaluated the therapeutic management and the clinical outcome assessed by disability of the arm, shoulder and hand (DASH) score and subjective shoulder value (SSV). All procedures were performed through a deltopectoral approach and consisted in a debridement and synovectomy, articular surface resection and insertion of a custom made antibiotic enriched cement spacer. Shoulder arthroplasty was performed in a second stage.RESULTSMean age was 61 years (range, 47-70 years). Four patients had previous surgeries ahead of the septic arthritis. All patients had a surgical debridement ahead of the index procedure. Mean follow-up was 13 mo (range, 6-24 mo). Persistent microbiological infection was confirmed in all five cases at the time of the first stage of the procedure. The shoulder arthroplasties were performed 6 to 12 wk after insertion of the antibiotic-loaded spacer. There were two hemi and three reverse shoulder arthroplasties. Infection was successfully eradicated in all patients. The clinical outcome was satisfactory with a mean DASH score and SSV of 18.4 points and 70% respectively.CONCLUSIONShort interval two-stage approach for septic shoulder arthritis is an effective treatment option. It should nonetheless be reserved for selected patients with advanced disease in which lavage and debridement have failed.

Changes of Supraspinatus Muscle Volume and Fat Fraction After Successful or Failed Arthroscopic Rotator Cuff Repair

Background: Muscle atrophy and fatty infiltration are limiting factors for successful rotator cuff (RC) repair. Quantitative data regarding these hallmarks of degenerative muscle changes after RC repair in humans are scarce. By utilizing a new application of the 6-point Dixon magnetic resonance imaging technology, 3-dimensional volume and fat fraction analysis of the whole RC muscle have become possible. Purpose: Quantitative analysis of atrophy and fatty infiltration of the supraspinatus muscle after healed and failed RC tendon-to-bone repair. Study Design: Cohort study; Level of evidence, 3. Methods: Muscle volume and fat fraction were measured preoperatively and at 3 and 12 months postoperatively in 19 failed and 21 healed arthroscopic supraspinatus tendon repairs, with full muscle volume segmentation and magnetic resonance Dixon sequences. Results: In both groups, the muscle volume initially decreased 3 months after RC repair by –3% in intact (P = .140) and –10% in failed repair (P = .004) but recovered between 3 and 12 months to 103% (P = .274) in intact and 92% (P = .040) in failed repairs when compared with the preoperative volume (difference of change between groups, preoperative to 12 month: P = .013). The supraspinatus muscle’s fat fraction did not significantly change after successful repair (6.5% preoperative, 6.6% after 3 months, and 6.7% after 12 months; all nonsignificant). There was, however, a significant increase from 7.8% to 10.8% at 3 months (P = .014) and 11.4% at 12 months (P = .020) after failed repair (difference between groups at 3- and 12-month follow-up: P = .018 and P = .001, respectively). Conclusion: After successful arthroscopic repair, RC tendon tear–induced fatty infiltration can be almost stopped, and muscle atrophy can even be slightly reversed. In case of a failed repair, however, these changes are further pronounced during the first 3 postoperative months but seem to stabilize thereafter.

Proresolving Mediators LXB4 and RvE1 Regulate Inflammation in Stromal Cells from Patients with Shoulder Tendon Tears

Tendon stromal cells isolated from patients with chronic shoulder rotator cuff tendon tears have dysregulated resolution responses. Current therapies do not address the biological processes concerned with persistent tendon inflammation; therefore, new therapeutic approaches that target tendon stromal cells are required. We examined whether two specialized proresolving mediators (SPMs), lipoxin B4 (LXB4) and resolvin E1 (RvE1), modulate the bioactive lipid mediator profiles of IL-1β–stimulated tendon cells derived from patients with shoulder tendon tears and healthy volunteers. We also examined whether LXB4 or RvE1 treatments moderated the proinflammatory phenotype of tendon tear stromal cells. Incubation of IL-1β–treated patient-derived tendon cells in LXB4 or RvE1 up-regulated concentrations of SPMs. RvE1 treatment of diseased tendon stromal cells increased 15-epi-LXB4 and regulated postaglandin F2α. LXB4 or RvE1 also induced expression of the SPM biosynthetic enzymes 12-lipoxygenase and 15-lipoxygenase. RvE1 treatment up-regulated the proresolving receptor human resolvin E1 compared with vehicle-treated cells. Incubation in LXB4 or RvE1 moderated the proinflammatory phenotype of patient-derived tendon tear cells, regulating markers of tendon inflammation, including podoplanin, CD90, phosphorylated signal transducer and activator of transcription 1, and IL-6. LXB4 and RvE1 counterregulate inflammatory processes in tendon stromal cells, supporting the role of these molecules as potential therapeutics to resolve tendon inflammation.

Double Row–Equivalent PASTA Repair Technique

Articular surface partial rotator cuff tendon tears are a common source of shoulder pain and dysfunction, and there is no consensus regarding the optimal arthroscopic treatment. Commonly accepted techniques, such as transtendinous repair or tear takedown with primary repair, may violate healthy tendon tissue and increase the suture anchor density. In this note, we describe an outside-in double row–equivalent technique for repair of partial articular-sided rotator cuff tears. A medial row of inverted horizontal mattress stitches is placed percutaneously using spinal needles to shuttle partially absorbable braided sutures into the joint. The technique may incorporate a soft tissue biceps tenodesis into the rotator cuff with a second, oblique medial row mattress stitch. Suture limbs are retrieved and tied in the subacromial space and then secured to a lateral anchor. The result is a side-to-side double row–equivalent rotator cuff repair, anatomically reproducing the footprint of the rotator cuff without removing healthy tissue. We believe this is an efficient and reproducible technique that preserves intact bursal tissue, limits implant costs, and produces reliable healing in partial articular-sided tears of the rotator cuff.

Dynamic Ultrasound Imaging for the Diagnosis of Superior Labrum Anterior to Posterior (SLAP) Lesion

A 40-yr-old woman had contusion on her left shoulder in a traffic accident 2 wks before clinical examination at our department. Afterward, she could not raise her left arm because of severe pain. Plain radiographs were negative and medical treatment with a nonsteroidal anti-inflammatory drug had been ineffective. Application of hot packs and interferential current therapy resulted in limited pain relief. She was referred for an ultrasound (US) examination for a rotator cuff tendon tear. Prescanning physical findings showed tenderness over the coracoid process, limited range of shoulder abduction, and flexion. The painful arc, Hawkins-Kennedy, and Neer tests were positive. Ultrasound imaging of the supraspinatus tendon disclosed a small partial tear. Herewith, because her symptom severity was not consistent with the US finding, we further assessed the superior labrum concerning her trauma history. Using a curvilinear transducer in the oblique coronal plane,1 we identified a hypoechoic slip inside the hyperechoic triangular labrum. The proximal portion of the biceps tendon (long head) appeared intact. With forcefully pulling the arm downward, the slip was enlarged with fluid filling the gap. Keeping the arm in abduction, a dynamic examination was conducted by pronation, supination, and forceful traction of the forearm1 (Figs. 1A, B, Video 1). The diagnosis of superior labrum anterior to posterior (SLAP) lesion was also confirmed with magnetic resonance imaging (Figs. 1C, D). Under US guidance, a single injection of 10 ml of 15% dextrose was applied to the lesion in an attempt to cover the superior labrum and proximal biceps tendon. Her symptoms gradually improved.FIGURE 1: A, Fibrillar band (arrowhead) of the long head of the biceps tendon crosses around the humeral head and finally inserts on the superior labrum (crosses). The hyperechoic triangular shape of the labrum becomes blunting with the anechoic effusion around it (asterisk). B, The US beam is perpendicular to the labrum under the heel-toe maneuver of the probe. The hypoechoic foci are seen in the labrum (arrow). T2 short-TI inversion recovery coronal (C) and axial (D) magnetic resonance images also show the architecture of the superior labrum (crosses) and the hyperintense lesions (arrow).The SLAP lesion is a tear of the superior labrum near the attachment of the long head of the biceps tendon. It is not rare in athletes with frequent overhead throwing activities and is occasionally caused by direct contusion on shoulders during abduction and external rotation. Anterior shoulder pain and multidirectional instability are the common chief complaints. Hawkins, Neer, and Speed tests may be sensitive, but not specific for SLAP lesions.2,3 For its diagnosis, magnetic resonance arthrography—detecting the clefts in the labrum or between the labrum and the glenoid—is the criterion standard.4 Until now, there are few articles addressing the diagnosis of SLAP lesions by using US. Because the physicians commonly use a linear transducer to scan the shoulders, US imaging might yield limited penetration and resolution for deeper structures. In addition, visualization of the labrum requires specific positioning of the patient with shoulder abduction and external rotation. To parallel the orientation of the long head of the biceps tendon, the probe is placed between the coracoid process and acromioclavicular joint. Otherwise, the labrum will be hindered under the coracoid process. In our case, we chose the curvilinear probe for its better penetration. Furthermore, the radiation pattern of the US beam permits us to visualize the structure under the coracoid process. Last but not least, with dynamic US imaging while pulling the affected shoulder downward to enlarge the slip,1 architecture of the labrum, biceps tendon origin, and hypoechoic foci in the hyperechoic labrum can easily be defined. In short, showing its applicability for SLAP lesions, we imply that US imaging of the superior labrum needs to be performed in patients with shoulder trauma.

Adipocyte hyperplasia: the primary mechanism of supraspinatus intramuscular fat accumulation after a complete rotator cuff tendon tear: a study in the rabbit

ABSTRACTIntramuscular fat (IMF) accumulates in muscles of the rotator cuff after tendon tear. The number and cross-sectional area of fat clumps and of adipocytes were quantified on osmium tetroxide stained sections of the proximal, middle and distal quarters of SSP muscles 4, 8 and 12 weeks after SSP tendon division in a rabbit model. Linear mixed-effects models were fitted to the data and statistical significance was evaluated by ANOVA. Both the number (P<0.001) and cross-sectional area (P<0.0005) of fat clumps increased after tendon detachment while time had no significant effect (both at P>0.01). IMF accumulation was more important in the distal quarter of detached SSP muscle near tendon sectioning and characterized by increases of the number (P<0.0005) and cross-sectional area of fat clumps (P<0.0005) compared to the proximal quarter. Adipocyte number increased after tendon detachment (P<0.0005) and over time (P<0.01). The cross-sectional area of adipocytes increased in the detached group compared to controls (P<0.01) while time had no significant effect (P>0.01). Interestingly, the number of adipocytes in the distal quarter increased (P<0.0005) but the cross-sectional area was smaller (P<0.0005) compared to adipocytes in the proximal quarter. Adipocyte hyperplasia localized near tendon sectioning was the main contributor to fat accumulation in the detached SSP muscles.

The Challenges of Arthroscopic Diagnosis of Subscapularis Tears

Visualisation of subscapularis lesions is difficult during open surgery. Introduction of arthroscopic procedures for rotator cuff surgery improved the diagnosis of subscapularis tears, but it still can be more challenging than for other rotator cuff tendon tears. The SFA classification of subscapularis tears is reproducible and correlates well with the arthroscopic findings. The arthroscopic diagnosis of subscapularis tear is made easier by: shoulder internal rotation, biceps tenodesis, dissection of the rotator interval, recognition of the sentinel and comma signs.

Tear characteristics and surgeon influence repair technique and suture anchor use in repair of superior-posterior rotator cuff tendon tears

The factors that associate with surgical decisions about repair technique and the number of suture anchors used in rotator cuff repair have not been previously investigated. This study investigated the extent to which patient, surgeon, and surgical factors associate with performing single-row vs. double-row repair technique and ultimately with the number of suture anchors used. Our institution's prospective surgical cohort was queried for patients undergoing suture anchor repair of superior-posterior rotator cuff tendon tears between February 2015 and August 2017. Exclusion criteria were patients with isolated subscapularis tears, tears that were not repaired, repairs without suture anchors, repairs involving graft augmentation, and repairs by surgeons with fewer than 10 cases. Multivariable statistical modeling was used to investigate associations between patient and surgical factors and the choice of repair technique and number of suture anchors used. A total of 925 cases performed by 13 surgeons met inclusion criteria. Tear type (full thickness), tear size (medium, large, and massive), a greater number of torn tendons, repair type (arthroscopic), and surgeon were significantly associated with performing a double-row over a single-row repair. Tear size, a greater number of torn tendons, double-row repair technique, and surgeon were significantly associated with a greater number of anchors used for repair. Our findings suggest that in the absence of data to conclusively support a clinical benefit of one repair technique over another, surgeons' training, experience, and inherent practice patterns become the primary factors that define their surgical methods.

Therapeutic Effects of Umbilical Cord Blood-Derived Mesenchymal Stem Cells Combined with Polydeoxyribonucleotides on Full-Thickness Rotator Cuff Tendon Tear in a Rabbit Model

While therapies using mesenchymal stem cells (MSCs) to treat rotator cuff tendon tear (RCTT) have yielded some promising preliminary results, MSCs therapy has not yet completely regenerated full-thickness RCTT (FTRCTT). It has recently been reported that polydeoxyribonucleotide (PDRN) is effective in the treatment of chronic rotator cuff disease. We hypothesized that local injection of human umbilical cord blood-derived (UCB)–MSCs with PDRN would be more effective in regenerating tendon tear than UCB-MSCs alone. The purpose of this study was to evaluate the effects of UCB–MSCs combined with different doses of PDRN on the regeneration of RCTT in a chronic RCTT model by using a rabbit model. New Zealand white rabbits (n = 24) with FTRCTT were allocated randomly into three groups (8 rabbits per group). Three different injectants (G1-S, 0.2 mL UCB-MSCs; G2-P1, 0.2 mL UCB-MSCs with one injection of 0.2 mL PDRN; G3-P4, 0.2 mL UCB-MSCs, and four injections of 0.2 mL PDRN per week) were injected into FTRCTT under US-guidance. After the rabbits were euthanized, we evaluated ross morphological and histological change. Motion analysis was also performed. There were significant differences in gross morphological changes between before, and at 4 weeks after injection, in all three groups, but no differences were found among the three groups. Masson’s trichrome (MT) or anti-type 1 collagen antibody (COL-1)-positive cell densities in G2-P1 and G3-P4 were improved significantly compared with those in G1-S, but showed no significant difference between G2-P1 and G3-P4. On motion analysis, walking distance and fast walking time in G2-P1 and G3-P4 were significantly longer/higher than those in G1-S, but showed no significant differences between G2-P1 and G3-P4. These results demonstrated that there was no significant difference in the gross morphologic change of tendon tear between UCB-MSCs only and combination with PDRN injection in rabbit model of chronic traumatic FTRCTT. Furthermore, there were no significant differences in the regenerative effects between high and low doses of (0.8 and 0.2) mL of PDRN.

Cross-talk between shoulder and neck pain: an imaging study of association between rotator cuff tendon tears and cervical foraminal stenosis.

Rotator cuff tendon tears are prevalent in patients with shoulder pain, the third most common musculoskeletal complaint. As shoulders are largely innervated by cervical nerves, it seems possible that rotator cuff pathology could have an association with cervical spine disorders, although few studies have investigated this possibility. This study aimed to explore the association between rotator cuff tendon tears and cervical radiculopathy (at C5 and C6 levels) in the shoulder pain population.We conducted a retrospective review of a clinical registry of shoulder ultrasound (US) examinations and cervical spine radiographs, recruiting a total of 126 patients with cervical spine radiographs taken within 1 year of US examinations. Foraminal stenosis was grouped into 4 categories: C4/5 intervertebral foramen only, C5/6 intervertebral foramen only, both C4/5 and C5/6 intervertebral foramina, and neither C4/5 nor C5/6 intervertebral foramen. The groups with and without rotator cuff tendon tears were compared for various factors, using the Mann-Whitney U test for continuous variables and the χ test for categorical variables. A multivariate analysis was conducted using a logistic regression model to investigate the association between rotator cuff tendon tears and cervical foraminal stenosis.Patients with rotator cuff tendon tears tended to be older and had more night-time pain. No significant association was identified between rotator cuff tendon tears and cervical foraminal stenosis at C5 and C6 levels. The only factor significantly predicting rotator cuff tendon tears was old age (odds ratio, 1.04; 95% confidence interval: 1.00-1.09).In patients with shoulder or neck pain, no significant association existed between rotator cuff tendon tears and cervical foraminal stenosis (at the C5 and C6 levels). When patients present with undifferentiated shoulder and neck pain, physicians should take a detailed history, perform physical examinations and imaging studies of both the neck and shoulder regions.