Expression of interleukin‐1β, cyclooxygenase‐2, and prostaglandin E2 in a rotator cuff tear in rabbits

We investigated the specific factors related to shoulder pain due to a rotator cuff tear using a model in rabbits. A rotator cuff tear was surgically created, and the expression of interleukin‐1β (IL‐1β), prostaglandin E2 (PGE2), and cyclooxygenase‐2 (COX‐2) was analyzed. In the supernatant of the tissue culture of the torn tendon, IL‐1β production was detected. The amount of IL‐1β was highest 1 day after injury, and then decreased gradually to 21 days. PGE2, the mediator of pain and the product of COX‐2, was also detected in the supernatant of the tissue culture. The production of PGE2 significantly increased to 7 days after injury, and then decreased to 21 days. RT‐PCR analysis confirmed the mRNA expression of IL‐1β and COX‐2 in the torn tendon. Immunohistochemical study demonstrated that cells in the tendon stump were immunopositive for IL‐1β and COX‐2. Furthermore, in the affected joint, articular chondrocytes in the remote area from the tear expressed COX‐2 strongly. When the rotator cuff is torn, IL‐1β is produced in the torn tendon, and stimulates the expression of COX‐2 in not only the torn tendon but also in articular chondrocytes. The COX‐2 then produces PGE2, which would mediate shoulder pain. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:92–97, 2007     

Efficacy of hyaluronic acid or steroid injections for the treatment of a rat model of rotator cuff injury

This study evaluated dorsal root ganglia from C3–C7, analyzed gait, and compared the expression of calcitonin gene‐related peptide (CGRP) which was a marker of inflammatory pain in a rat rotator cuff tear model in which the supraspinatus and infraspinatus tendons were detached; comparisons were made to a sham group in which only the tendons were exposed. Fluorogold was injected into the glenohumeral joint 21 days after surgery in both groups, and saline, steroids, or hyaluronic acid was injected into the glenohumeral joint in the rotator cuff tear group 26 days after surgery. The proportions of CGRP‐immunoreactive neurons were higher and the gait parameters were impaired in the rotator cuff tear group compared to in the sham group. However, the CGRP expression was reduced and the gait was improved with steroid or hyaluronic acid injection compared to saline, suggesting that both hyaluronic acid and steroid injections suppressed of inflammation which thought to be provided pain relief. While there were no significant differences, the suppression of CGRP expression and the improved gait after hyaluronic acid and steroid injections suggested that both methods were effective for rat rotator cuff tear model. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1861–1867, 2015.     

Increased IL‐1β expression and myofibroblast recruitment in subacromial bursa is associated with rotator cuff lesions with shoulder stiffness

We evaluated whether proinflammatory cytokine expression and myofibroblast recruitment in subacromial bursa was linked to rotator cuff lesions with shoulder stiffness. We analyzed expressions of IL‐1β, IL‐6, and TNF‐α in subacromial bursa and joint fluid collected from 14 patients with cuff tears with stiffness as a study group (Group I) and 14 patients with rotator cuff tears without shoulder stiffness as a control group (Group II) using real‐time RT‐PCR, immunohistochemistry, and ELISA. Myofibroblast apoptosis in subacromial bursa was analyzed using terminal deoxynucleotidyl transferase ‐mediated deoxyuridine triphosphate‐biotin nick end‐labeling (TUNEL) and α‐smooth muscle actin immunofluorescence staining. Shoulder function was evaluated using the Constant score. Group I had higher mRNA expression (p < 0.001) and immunoreactivities (p < 0.001) of IL‐1β. They also had higher levels of IL‐1β, IL‐6, and TNF‐α in joint fluid. Increased IL‐1β mRNA expression in the subacromial bursa and IL‐1β levels in joint fluid were correlated with a preoperative deficit in shoulder motion (p < 0.001) and preoperative Constant scores (p < 0.001). Immunofluorescence observations showed that Group I subjects had more myofibroblasts (p < 0.001) than Group II. In Group II, a significant correlation was found between apoptotic myofibroblasts and total myofibroblasts (p = 0.002), but not in Group I (p = 0.510). Increased expression of IL‐1β and myofibroblast recruitment in the subacromial bursa in rotator cuff lesions are linked to shoulder stiffness. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1090–1097, 2008     

Biomechanical comparison of single‐row,double‐row,and transosseous‐equivalent repair techniques after healing in an animal rotator cuff tear model

The transosseous‐equivalent (TOE) rotator cuff repair technique increases failure loads and contact pressure and area between tendon and bone compared to single‐row (SR) and double‐row (DR) repairs, but no study has investigated if this translates into improved healing in vivo. We hypothesized that a TOE repair in a rabbit chronic rotator cuff tear model would demonstrate a better biomechanical profile than SR and DR repairs after 12 weeks of healing. A two‐stage surgical procedure was performed on 21 New Zealand White Rabbits. The right subscapularis tendon was transected and allowed to retract for 6 weeks to simulate a chronic tear. Repair was done with the SR, DR, or TOE technique and allowed to heal for 12 weeks. Cyclic loading and load to failure biomechanical testing was then performed. The TOE repair showed greater biomechanical characteristics than DR, which in turn were greater than SR. These included yield load (p < 0.05), energy absorbed to yield (p < 0.05), and ultimate load (p < 0.05). For repair of a chronic, retracted rotator cuff tear, the TOE technique was the strongest biomechanical construct after healing followed by DR with SR being the weakest. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1254–1260, 2013     

Effect of platelet‐rich plasma on the biologic activity of the human rotator‐cuff fibroblasts: A controlled in vitro study

To assess the in vitro effect of platelet‐rich plasma (PRP) on biological activity of the human rotator cuff fibroblasts and to describe the optimal dose‐response to maximize cellular stimulation while reducing potential risk. Rotator cuff (RC) fibroblasts of n = 6 patients (mean age of 65.2 years) undergoing arthroscopic cuff tear reconstruction were cultured in vitro for 21 days and stimulated with PRP in three different concentrations (1‐, 5‐, and 10‐fold). Samples were obtained for DNA and GAG measurement at 1, 7, 14, and 21 days. The biological outcomes were regressed on the PRP concentration. The application of PRP significantly influenced the fibroblast proliferation and activity of the human rotator cuff with elevated glycosaminoglycan (GAG) and DNA levels. The dosage of PRP had the significantly highest impact on this proliferation using a onefold or fivefold application. PRP has a significant effect on fibroblast proliferation of the human rotator cuff in vitro with an optimal benefit using a onefold or fivefold PRP concentration. This study justifies further in vivo investigations using PRP at the human rotator cuff. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1249–1253, 2013     

Mechanical properties of the long‐head of the biceps tendon are altered in the presence of rotator cuff tears in a rat model

Rotator cuff tears are disabling conditions that result in changes in joint loading and functional deficiencies. Clinically, damage to the long‐head of the biceps tendon has been found in conjunction with rotator cuff tears, and this damage is thought to increase with increasing tear size. Despite its importance, controversy exists regarding the optimal treatment for the biceps. An animal model of this condition would allow for controlled studies to investigate the etiology of this problem and potential treatment strategies. We created rotator cuff tears in the rat model by detaching single (supraspinatus) and multiple (supraspinatus + infraspinatus or supraspinatus + subscapularis) rotator cuff tendons and measured the mechanical properties along the length of the long‐head of the biceps tendon 4 and 8 weeks following injury. Cross‐sectional area of the biceps was increased in the presence of a single rotator cuff tendon tear (by ～150%), with a greater increase in the presence of a multiple rotator cuff tendon tear (by up to 220%). Modulus values decreased as much as 43 and 56% with one and two tendon tears, respectively. Also, multiple tendon tear conditions involving the infraspinatus in addition to the supraspinatus affected the biceps tendon more than those involving the subscapularis and supraspinatus. Finally, biceps tendon mechanical properties worsened over time in multiple rotator cuff tendon tears. Therefore, the rat model correlates well with clinical findings of biceps tendon pathology in the presence of rotator cuff tears, and can be used to evaluate etiology and treatment modalities. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:416–420, 2009     

Interleukin‐1β stimulates stromal‐derived factor‐1α expression in human subacromial bursa

Chemokines produced by synoviocytes of the subacromial bursa are up‐regulated in subacromial bursitis and rotator cuff disease. We hypothesized that SDF‐1α production in bursal synoviocytes may be induced by local cytokines such as interleukin IL‐1β and IL‐6. Subacromial bursa specimens were obtained from patients undergoing shoulder surgery. Bursal specimens were stained with anti‐human antibodies to IL‐1, IL‐6, and SDF‐1α by immunohistochemistry and compared to normal and rheumatoid controls. Bursal cells were also isolated from specimens and cultured. Early passaged cells were then treated with cytokines (IL‐1β and IL‐6) and SDF‐1α expression was measured by ELISA and RT‐PCR. SDF‐1α, IL‐1β, and IL‐6 were expressed at high levels in bursitis specimens from human subacromial bursa compared to normal controls. In cultured bursal synoviocytes, there was a dose‐dependent increase in SDF‐1α production in the supernatants of cells treated with IL‐1β. SDF‐1α mRNA expression was also increased in bursal cells treated with IL‐1β. IL‐6 caused a minimal but not statistically significant increase in SDF‐1α expression. SDF‐1α, IL‐1β, and IL‐6 are expressed in the inflamed human subacromial bursal tissues in patients with subacromial bursitis. In cultured bursal synoviocytes, SDF‐1α gene expression and protein production are stimulated by IL‐1β. IL‐1β produced by bursal syvoviocytes and inflammatory cells in the human subacromial bursa is an important signal in the inflammatory response that occurs in subacromial bursitis and rotator cuff disease. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1695–1699, 2011     

Rotator cuff muscle degeneration and tear severity related to myogenic,adipogenic, and atrophy genes in human muscle

Large rotator cuff tear size and advanced muscle degeneration can affect reparability of tears and compromise tendon healing. Clinicians often rely on direct measures of rotator cuff tear size and muscle degeneration from magnetic resonance imaging (MRI) to determine whether the rotator cuff tear is repairable. The objective of this study was to identify the relationship between gene expression changes in rotator cuff muscle degeneration to standard data available to clinicians. Radiographic assessment of preoperative rotator cuff tear severity was completed for 25 patients with varying magnitudes of rotator cuff tears. Tear width and retraction were measured using MRI, and Goutallier grade, tangent (tan) sign, and Thomazeau grade were determined. Expression of myogenic‐, adipogenic‐, atrophy‐, and metabolism‐related genes in biopsied muscles were correlated with tear width, tear retraction, Goutallier grade, tan sign, and Thomazeau grade. Tear width positively correlated with Goutallier grade in both the supraspinatus (r = 0.73) and infraspinatus (r = 0.77), along with tan sign (r = 0.71) and Thomazeau grade (r = 0.68). Decreased myogenesis (Myf5), increased adipogenesis (CEBPα, Lep, Wnt10b), and decreased metabolism (PPARα) correlated with radiographic assessments. Gene expression changes suggest that rotator cuff tears lead to a dramatic molecular response in an attempt to maintain normal muscle tissue, increase adipogenesis, and decrease metabolism. Fat accumulation and muscle atrophy appear to stem from endogenous changes rather than from changes mediated by infiltrating cells. Results suggest that chronic unloading of muscle, induced by rotator cuff tear, disrupts muscle homeostasis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2808–2814, 2017.

     

老年肱骨近端骨折合并肩袖损伤的年龄分布及骨折分型分析

［摘要］ 目的 本研究旨在探讨肱骨近端骨折合并肩袖损伤与年龄分布及骨折分型的相关性。方法 回顾性分析336例老年肱骨近端骨折病人的临床资料,比较不同年龄分层肱骨近端骨折合并肩袖损伤的发生率,并根据肱骨近端骨折分型Neer分型比较不同骨折类型肩袖损伤的发生率。结果 随着年龄的增加,老年肱骨近端骨折合并肩袖损伤的病人的比例增加。合并肩袖损伤的肱骨近端骨折病人的平均年龄（72.9±8.5）与不合并肩袖损伤的病人的平均年龄（65.7±9.1）差异有统计学意义（t=6.912,P=0.000）。肱骨近端骨折分型Neer分型3部分骨折合并肩袖损伤的发生率最高,为54.8%（92/168）。结论 随着年龄的增加,老年肱骨近端骨折合并肩袖损伤病人比例逐渐增加;肱骨近端骨折分型Neer分型3部分骨折常合并肩袖损伤。     

Effect of tamoxifen on fatty degeneration and atrophy of rotator cuff muscles in chronic rotator cuff tear: An animal model study

Fatty degeneration of the rotator cuff muscles is an irreversible change resulting from chronic rotator cuff tear and is associated with poor clinical outcomes following rotator cuff repair. We evaluated the effect of Tamoxifen, a competitive estrogen receptor inhibitor, on fatty degeneration using a mouse model for chronic rotator cuff tear. Sixteen adult mice were divided into two diet groups (Tamoxifen vs. Regular) and subjected to surgical creation of a large rotator cuff tear and suprascapular nerve transection in their left shoulder with the right shoulder serving as a control. The rotator cuff muscles were harvested at 16 weeks and subjected to histology and RT‐PCR for adipogenic and myogenic markers. Histology showed substantially decreased atrophy and endomysial inflammation in Tamoxifen group, but no significant differences in the amount of intramuscular adipocytes and lipid droplets compared to the Regular group. With RT‐PCR, the operated shoulders showed significant upregulation of myogenin and PPAR‐γ, and downregulation of myostatin compared to the nonsurgical shoulder. No significant differences of gene expression were found between the two diet groups. Our study demonstrated that tamoxifen diet leads to decreased muscle atrophy and inflammatory changes following chronic rotator cuff tear, but has no apparent effect on adipogenesis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1846–1853, 2015.     

Porcine IL‐6, IL‐1β, and TNF‐α regulate the expression of pro‐inflammatory‐related genes and tissue factor in human umbilical vein endothelial cells

Whether porcine cytokines are induced after pig‐to‐primate xenotransplantation and activate human cells remains unknown. First, we investigated the regulation of porcine IL‐6, IFN‐γ, IL‐1β, and TNF‐α in xenotransplantation using an in vitro model in which porcine aortic endothelial cells (PAECs) and porcine peripheral blood mononuclear cells (PBMCs) were stimulated with human serum. Downstream cytokines/chemokines were monitored. Pro‐inflammatory cytokines (IL‐6, IFN‐γ, and IL‐1β) and chemokines (IL‐8, MCP‐1, and CXCL2) were upregulated in the both cell types. TNF‐α was induced 10‐fold in PAECs, but not in PBMCs. Then, we assessed the role of porcine IL‐6, IFN‐γ, IL‐1β, and TNF‐α in xenotransplantation using western blotting and real‐time PCR. Human umbilical vein endothelial cells (HUVECs) were selected as the target cells. Signaling pathways and downstream genes, such as those related to adhesion, inflammation, and coagulation, and chemokines were investigated. Porcine IL‐1β and TNF‐α significantly activated NF‐κB and P38, and STAT3 was activated by porcine IL‐6 in HUVECs. The adhesion genes (E‐selectin, VCAM‐1, and ICAM‐1), inflammatory cytokines (IL‐6, IL‐1β, and TNF‐α), chemokines (MCP‐1 and IL‐8), and the pro‐coagulation gene (tissue factor) were upregulated by porcine IL‐1β and TNF‐α. Porcine IL‐6 increased the expression of ICAM‐1, IL‐6, MCP‐1, and tissue factor, but decreased IL‐8 expression slightly. Surprisingly, porcine IFN‐γ could not activate STAT1 or regulate the expression of any of the above genes in HUVECs. In conclusion, these findings suggest that porcine IL‐6, IL‐1β, and TNF‐α activate HUVECs and regulate downstream genes expression, which may promote inflammation and coagulation response after xenotransplantation.     

The effects of chronic unloading and gap formation on tendon‐to‐bone healing in a rat model of massive rotator cuff tears

The objective of this study was to understand the effect of pre‐repair rotator cuff chronicity on post‐repair healing outcomes using a chronic and acute multi‐tendon rat rotator cuff injury model. Full‐thickness dual tendon injuries (supra‐ and infraspinatus) were created unilaterally in adult male Sprague Dawley rats, and left chronically detached for 8 or 16 weeks. After chronic detachment, tears were repaired and acute dual tendon injuries were created and immediately repaired on contralateral shoulders. Tissue level outcomes for bone, tendon, and muscle were assessed 4 or 8 weeks after repair using histology, microcomputed tomography, biomechanical testing, and biochemical assays. Substantial gap formation was seen in 35% of acute repairs and 44% of chronic repairs. Gap formation negatively correlated with mechanical and structural outcomes for both healing time points regardless of injury duration. Bone and histomorphometry, as well as biomechanics, were similar between acute and chronic injury and repair regardless of chronicity and duration of healing. This study was the first to implement a multi‐tendon rotator cuff injury with surgical repair following both chronic and acute injuries. Massive tear in a rodent model resulted in gap formation regardless of injury duration which had detrimental effects on repair outcomes. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:439–447, 2014.     

Botulinum toxin is detrimental to repair of a chronic rotator cuff tear in a rabbit model

Re‐tear continues to be a problem after rotator cuff repair. Intramuscular botulinum toxin (Botox) injection can help optimize tension at the repair site to promote healing but could have an adverse effect on the degenerated muscle in a chronic tear. We hypothesized that Botox injection would improve repair characteristics without adverse effect on the muscle in a chronic rotator cuff tear model. The supraspinatus tendon of both shoulders in 14 rabbits underwent delayed repair 12 weeks after transection. One shoulder was treated with intramuscular Botox injection and the other with a saline control injection. Six weeks after repair, outcomes were based on biomechanics, histology, and magnetic resonance imaging. Botox‐treated repairs were significantly weaker (2.64 N) than control repairs (5.51 N, p = 0.03). Eighty percent of Botox‐treated repairs and 40% of control repairs healed with some partial defect. Fatty infiltration of the supraspinatus was present in all shoulders (Goutallier Grade 3 or 4) but was increased in the setting of Botox. This study provides additional support for the rabbit supraspinatus model of chronic cuff tear, showing consistent fatty infiltration. Contrary to our hypothesis, Botox had a negative effect on repair strength and might increase fatty infiltration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1152–1157, 2015.     

Tissue‐engineered tendon constructs for rotator cuff repair in sheep

Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue‐engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue‐engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG‐RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6‐month recovery, the grafted and contralateral shoulders were removed, imaged using X‐ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC‐RCs reached 31% of the native tendon tangent modulus, which was a modest, non‐significant, 11% increase over that of the suture‐only repairs. However, the histological analysis showed the regeneration of a native‐like enthesis in the ETG‐RC‐repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:289–299, 2018.     

Lysophosphatidic acid‐induced RhoA signaling and prolonged macrophage infiltration worsens fibrosis and fatty infiltration following rotator cuff tears

Previous studies have suggested that macrophage‐mediated chronic inflammation is involved in the development of rotator cuff muscle atrophy and degeneration following massive tendon tears. Increased RhoA signaling has been reported in chronic muscle degeneration, such as muscular dystrophy. However, the role of RhoA signaling in macrophage infiltration and rotator muscle degeneration remains unknown. Using a previously established rat model of massive rotator cuff tears, we found RhoA signaling is upregulated in rotator cuff muscle following a massive tendon‐nerve injury. This increase in RhoA expression is greatly potentiated by the administration of a potent RhoA activator, lysophosphatidic acid (LPA), and is accompanied by increased TNFα and TGF‐β1 expression in rotator cuff muscle. Boosting RhoA signaling with LPA significantly worsened rotator cuff muscle atrophy, fibrosis, and fatty infiltration, accompanied with massive monocytic infiltration of rotator cuff muscles. Co‐staining of RhoA and the tissue macrophage marker CD68 showed that CD68+ tissue macrophages are the dominant cell source of increased RhoA signaling in rotator cuff muscles after tendon tears. Taken together, our findings suggest that LPA‐mediated RhoA signaling in injured muscle worsens the outcomes of atrophy, fibrosis, and fatty infiltration by increasing macrophage infiltraion in rotator cuff muscle. Clinically, inhibiting RhoA signaling may represent a future direction for developing new treatments to improve muscle quality following massive rotator cuff tears. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1539–1547, 2017.

     

两种不同术式治疗合并肩胛上神经损伤的巨大肩袖撕裂后神经恢复的临床对比研究

目的对比传统双排修复术与阔筋膜移植术两种术式治疗合并肩胛上神经损伤的巨大肩袖撕裂患者的功能恢复情况。 方法回顾性分析2013年1月至2018年1月因巨大肩袖撕裂损伤于本院行关节镜肩袖损伤修复术患者20例,其中传统双排缝合组（A组）10例,阔筋膜移植组（B组）10例。所有患者术前均经肩关节MRI及肌电图诊断为巨大肩袖损伤合并神经损伤。术后1个月、6个月定期随访患者。比较手术前后两组患者的疼痛视觉模拟评分（visual analogue scale,VAS）、美国加州大学洛杉矶分校（University of California at Los Angeles,UCLA）评分、Constant-Murely肩关节功能评分的变化情况。术后6个月复查肌电图及MRI评估肩袖愈合及神经恢复情况。 结果20例患者均获得随访,随访时间6~18个月。术后6个月A组VAS评分从术前（7.4±0.8）分下降到（2.3±1.7）分,差异有统计学意义（P<0.01）,UCLA评分从术前（11.5±1.4）分上升到（28.3±5.8）分,差异有统计学意义（P<0.01）,Constant-Murely评分从术前（45.6±6.2）分上升到（79.0±11.7）分,差异有统计学意义（P<0.01）。B组VAS评分从术前（7.9±0.6）分下降到（2.7±1.8）分,差异有统计学意义（P<0.01）,UCLA评分从术前（10.1±1.4）分上升到（26.9±6.9）分,差异有统计学意义（P<0.01）,Constant-Murely评分从术前（39.0±3.4）分上升到（72.9±9.4）分,差异有统计学意义（P<0.01）。术后6个月时两组患者VAS评分比较差异无统计学意义（P>0.05）,两组患者UCLA评分比较差异无统计学意义（P>0.05）,两组患者Constant-Murely评分比较差异无统计学意义（P>0.05）。术后6个月复查肌电图,A组患者无肩胛上神经损伤,B组患者中有5例患者仍有肩胛上神经损伤（P<0.01）。 结论关节镜下巨大肩袖损伤传统双排修复术及阔筋膜移植术均能改善患者肩关节功能,双排缝合对于肩胛上神经功能恢复的短期效果要比阔筋膜移植组好,但再撕裂可能性大。     

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

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

Partial cuff debridement for irreparable defects of the rotator cuff

The treatment of massive rotator cuff tears can pose a difficult problem for the unprepared orthopaedic surgeon.There are many ways to treat massive rotator cuff tears, and one viable option is debridement with acromioplasty. For this form of treatment to be successful, the surgeon must choose his patient carefully. This report will focus on patient selection, biomechanics, and postoperative rehabilitation. A thorough understanding of rotator cuff tear biomechanics is needed when treating a massive tear; thorough physical and radiological examinations will help the orthopedist understand the biomechanic characteristic of the patient's tear. A tear that is balanced in both the transverse and coronal planes is stable and functional and will do well with debridement. Conversely, a tear that is unbalanced in either the transverse or coronal planes is unstable and nonfunctional and will not do well with simple debridement. Nonfunctional tears demand an attempt at rotator cuff tendon repair to restore balance to the cuff, making the tear functional. Debridement of a functional tear can be successfully performed with arthroscopic or open technique. Preservation or reconstruction of the coracoacromial (CA) arch is important because it adds anterosuperior stability to the shoulder with a massive rotator cuff tear. Postoperative rehabilitation is as important as the surgery itself and will also be emphasized. Many surgeons have had success with debridement of massive rotator cuff tears; however, as with any procedure, proper understanding of the pathology and proper patient selection is paramount to obtaining a successful result.