Biomechanical analysis of tendon transfers for massive rotator cuff tears

OBJECTIVE: To determine why certain tendon transfers are mechanically more effective than other tendon transfers for the treatment of a massive rotator cuff tear. DESIGN: A tendon transfer procedure of latissimus dorsi, teres major or a combination of these two to the insertions of either teres minor, infraspinatus, supraspinatus, or subscapularis is simulated using a biomechanical musculoskeletal model of the upper extremity. BACKGROUND: Massive rotator cuff tears are not easily repaired. To compensate for the loss of rotator cuff function, techniques such as muscle transfers are developed. METHODS: Three range of motion tasks were used as input to the Delft shoulder and elbow model. The muscle parameters of the Delft shoulder and elbow model were modified to simulate a rotator cuff tear. A biomechanical analysis of the transferred muscles was performed, taking outcome variables such as moment arms, muscle length and muscle force into account. RESULTS: Due to the massive rotator cuff tear, an elevation and external rotation moment is lost. When the tendon was transferred to the insertions of infraspinatus or supraspinatus, the humerus was capable of elevating and externally rotating. CONCLUSIONS: On the basis of mechanical parameters such as moment arms, muscle length and force it can be concluded that a tendon transfer of the teres major to the supraspinatus insertion will produce the best functional outcome in the treatment of massive rotator cuff tears. RELEVANCE: To find biomechanical evidence for an optimal tendon transfer that will lead to improved treatment of patients with a massive rotator cuff tear.     

关节镜下治疗巨大肩袖撕裂的效果研究

目的探讨关节镜下治疗巨大肩袖撕裂的效果。方法选取2010年1月-2016年2月该院行全关节镜手术治疗的62例巨大肩袖撕裂患者为研究对象,根据年龄分为老年组(年龄≥65岁,n=23)和非老年组(年龄65岁,n=39),比较两组术前和术后12个月的美国肩肘外科协会(ASES)评分、美国加利福尼亚大学洛杉矶分校(UCLA)评分和Constant-Murley评分。结果老年组的年龄明显高于非老年组,差异有统计学意义(P0.05),两组患者的性别、病程、病因和有无肩部外伤史等其余基线资料比较,差异均无统计学意义(P0.05)。全部患者均未出现围手术期并发症,手术均成功完成。两组术后12个月的ASES评分、UCLA评分和Constant-Murley评分均明显高于术前,差异均有统计学意义(P0.05)。两组术前和术后12个月的ASES评分、UCLA评分和Constant-Murley评分比较,差异均无统计学意义(P0.05)。结论关节镜微创手术能有效改善巨大肩袖撕裂患者的肩关节功能,在老年患者中同样能取得良好效果,值得临床推广应用。     

关节镜下肩袖间隙滑移技术在巨大肩袖撕裂中的应用

目的观察关节镜下使用肩袖间隙滑移技术修补巨大肩袖撕裂的临床疗效。方法采用回顾性研究方法,选取2015年1月至2019年3月北京市平谷区医院收治的巨大肩袖撕裂患者42例,按照手术方式不同将患者分为切开修复组和关节镜修复组,每组各21例。切开修复组患者使用改良切开修复巨大肩袖撕裂,关节镜修复组患者使用关节镜下肩袖滑移技术修复巨大肩袖。记录并比较患者术前情况,包括患者的VAS评分、肩关节UCLA评分、肩关节Constant-Murley评分、肩袖受伤情况、受伤至手术的时间等。所有患者术后3个月和6个月门诊随访,记录并比较两组患者VAS评分、肩关节UCLA评分、肩关节Constant-Murley评分和末次随访患者满意度评分以评价两种手术疗效。结果两组患者术前各观察指标比较差异均无统计学意义(P>0.05)。术后3个月关节镜修复组VAS评分、肩关节UCLA评分和肩关节Constant-Murley评分分别是4.9±1.2分、29.1±4.5分和72.4±13.9分,而切开修复组上述指标分别为6.3±1.6分、21.7±3.9分和61.8±10.6分。关节镜修复组患者的疼痛VAS评分低于切开修复组,差异具有统计学意义(P<0.05);关节镜修复组患者的肩关节UCLA评分和肩关节Constant-Murley评分均高于切开修复组,差异具有统计学意义(P<0.05)。术后6个月,关节镜修复组VAS评分、肩关节UCLA评分和肩关节Constant-Murley评分分别是3.7±1.3分、32.6±4.7分和82.1±10.8分,而切开修复组上述指标分别为3.9±1.4分、32.8±4.5分和81.5±11.3分,差异均无统计学意义(P>0.05)。术后末次随访时,关节镜修复组患者的满意度评分(84.3±15.1分)显著高于切开修复组(72.9±12.3分),差异具有统计学意义(P<0.05)。结论关节镜下肩袖间隙滑移技术能够有效地修复巨大肩袖撕裂,比切开肩袖修复巨大肩袖撕裂术后康复得更快。     

肩袖撕裂MR影像分析

肩袖（Rotator cuff）是一个由冈上肌、冈下肌、小圆肌和肩胛下肌组成的肌腱环，从后、上、前面围绕着肩关节，维持着肩关节的稳定。肩袖撕裂是引起肩部疼痛和功能障碍的常见原因。MRI作为一种无创伤性检查手段，具有较高的软组织分辨力，能够多平面显示肩袖损伤情况，并能够反映其相关病理变化，在肩袖损伤诊断中具有十分重要的价值，已被广泛应用于临床。     

Treatment of irreparable rotator cuff tears

Irreparable rotator cuff tears are a challenging problem for patients and surgeons. There are several treatment options, but deciding the correct one for each patient can be difficult. Treatment options include physical therapy, arthroscopy, muscle transfers, reverse shoulder arthroplasty, and hemiarthroplasty. An understanding of the patient’s chief complaint and their functional ability to elevate their arm above horizontal should guide the treatment. This article reviews the current literature on various treatment options for irreparable rotator cuff tears, then outlines an algorithm for determining treatment.     

Sonographic detection of tears of the anterior portion of the rotator cuff (subscapularis tendon tears).

We studied the value of ultrasonography in identifying tears of the most anterior portion of the rotator cuff (subscapularis tendon tears). Shoulder sonography was performed on 1640 patients with shoulder symptoms, 435 of whom underwent surgery. Among the patients who were operated on, 17 had predominantly or exclusively subscapularis tendon tears; 14 of these were full-thickness and three were partial-thickness tears. Ultrasonography demonstrated 82% (14 of 17) of the subscapularis tendon tears; 86% (12 of 14) of the full-thickness tears and 67% (2 of 3) of the partial-thickness tears were correctly diagnosed with ultrasonography. Sonography can diagnose and show the size of subscapularis tendon tears reliably, but it necessitates that the arm can be externally rotated to the maximum extent when performing the study.     

富血小板血浆和干针疗法治疗肩袖部分撕裂的临床研究

目的：探讨超声引导下自体血提取富血小板血浆(PRP)注射结合干针疗法(DN)治疗肩袖部分撕裂的效果。方法：选取肩袖肌腱部分撕裂患者120例,按照数字随机法分为4组：玻璃酸钠(SH)组、PRP组、DN组、PRP+DN组,每组30例。SH组、PRP组、PRP+DN组均在超声引导下分别注射SH、PRP、PRP+DN,DN组仅进行针刺治疗。4组患者治疗后均进行基础运动康复治疗。治疗前及治疗后1个月、3个月、6个月通过超声于肌腱长轴测量损伤部位肌腱肿胀程度和撕裂范围,采用视觉模拟评分法(VAS)、美国加州大学肩关节评分表(UCLA)对4组患者进行评价。结果：相较于治疗前,治疗后各时间点PRP组、DN组、PRP+DN组患者表现为肌腱厚度减少、撕裂的范围减少(P<0.05),治疗后3个月、6个月,PRP+DN组肌腱厚度及撕裂范围较其它3组减少(P<0.05)。相较于治疗前,治疗后各时间点4组VAS评分均降低(P<0.05),UCLA评分均升高(P<0.05),治疗后3个月与6个月,PRP+DN组VAS评分低于、UCLA评分高于其它3组(P<0.05)。结论：超声引导下PRP注射结合DN治疗,肩袖部分撕裂可明显缓解患者肩部疼痛,促进肩功能快速恢复,具有良好的临床应用价值。     

Decreasing glenoid inclination improves function in shoulders with simulated massive rotator cuff tears

BACKGROUND: A massive rotator cuff tear leads to poor shoulder function as evidenced by diminished glenohumeral abduction and superior translation of the humeral head compared to its normal position. The inclination angle of the glenoid has been associated with rotator cuff tears. The objective of this study was to quantify the effect of a decreased glenoid inclination angle on glenohumeral kinematics during active abduction in shoulders with a simulated, massive rotator cuff tear. METHODS: Eight fresh-frozen full upper extremities were tested using a dynamic shoulder testing apparatus. After recording the kinematics of the intact shoulder, a massive rotator cuff tear was surgically simulated. An osteotomy of the glenoid was then performed and the inclination angle was decreased by 30 degrees . The translation of the humeral head during abduction and the maximum abduction angle were recorded. FINDINGS: With an intact rotator cuff minimal humeral head translation on the glenoid occurred and the maximum abduction angle was mean 85.5 degrees (SD 7.4 degrees ). A massive rotator cuff tear resulted in superior translation of the humeral head with impingement on the acromion. The maximum abduction angle was mean 15.5 degrees (SD 9.4 degrees ). Decreasing the inclination angle of the glenoid resulted in a significant reduction of superior humeral head translation during abduction and there was no impingement on the acromion. The maximum abduction achieved was mean 28.5 degrees (SD 17.0 degrees ). INTERPRETATION: From a clinical perspective the reduced superior translation may decrease shoulder pain since the humeral head no longer impinges on the acromion. Further investigations are necessary to assess if the improvement in abduction is clinically significant.     

超声诊断肩袖撕裂

目的 探讨直接及间接超声征象对肩袖撕裂分型的诊断价值。方法 收集52例于我院行肩关节镜手术的患者,所有患者均接受超声检查,计算直接、间接超声征象诊断肩袖撕裂的效能,并比较直接超声征象诊断肩袖撕裂亚型与关节镜结果的一致性。结果 直接征象诊断肩袖有无撕裂、全层撕裂、部分撕裂的准确率分别为90.38%（47/52）、96.15%（50/52）和86.54%（45/52）,且直接征象诊断肩袖撕裂亚型与关节镜结果的一致性较好。在间接征象中,3部位同时出现积液（肩峰下-三角肌下滑囊积液、肩关节腔积液及肱二头肌长头腱腱鞘积液）、三角肌滑囊疝及软骨分界征诊断肩袖撕裂的特异度分别为80.95%（17/21）、90.48%（19/21）及95.24%（20/21）。结论 直接联合间接超声征象诊断肩袖撕裂的分型具有较高的临床应用价值。     

巨大肩袖撕裂的机制与修复方法的研究进展

巨大肩袖撕裂因其损伤机制复杂,目前仍是骨科难题。对于其最佳治疗方法及术后效果,各学者报道也不尽相同。其主要的治疗方法包括保守治疗、肩关节清理及肩峰成形术、肱二头肌长头键切断或固定术、撕裂肌腱修复术、肌腱转位术及比较热门的上关节囊重建及反肩关节置换术。本文着重对巨大肩袖撕裂的机制和治疗方法的研究成果作一综述,以期为临床治疗提供参考。     

Ultrasonography of rotator cuff tears: a review of 500 diagnostic studies

Ultrasonography of the rotator cuff has been shown to be of value in diagnosing rotator cuff tears. This report summarizes our experience with our first 500 diagnostic examinations. All patients were examined in the hyperextended internal rotation view with commercially available high-resolution real-time ultrasound equipment. Patients were diagnosed as having a rotator cuff tear if a focal echogenic lesion or a defect within the rotator cuff was identified. This study confirmed the value of ultrasonography for the diagnosis of rotator cuff tears. Accuracy, sensitivity, and specificity all exceeded 90%, and correlated with surgical findings. This was better than arthrography in the same patient population. Ultrasound is an accurate noninvasive method of examining the rotator cuff for the presence of tears. We suggest that rotator cuff ultrasonography is the procedure of choice for the diagnosis of tears if adequate instrumentation is available.     

关节镜下治疗肩袖损伤21例报告

目的探讨运用关节镜治疗肩袖损伤方面的作用。方法在关节镜下对肩袖损伤进行缝合,同时行肩关节前肩峰成形术。结果本组21例根据美国UCLA功能评分标准进行评定,优良率达95.24%。结论关节镜下治疗肩袖损伤能明确诊断、探查盂肱关节的其他疾患、不损伤三角肌止点、无张力缝合肩袖、术后疼痛轻、可以早期功能锻炼、术后肩关节粘连少、瘢痕少。     

Biomechanics of latissimus dorsi transfer for irreparable posterosuperior rotator cuff tears

Background

Latissimus dorsi transfer is the treatment most frequently used for restoring function in shoulders with irreparable posterosuperior rotator cuff tears. Yet, functional outcomes of the transfers are unpredictable and vary among patients.

Methods

A three-dimensional upper-extremity computational model was used to simulate and analyze the biomechanical consequences of transferring the latissimus dorsi to four attachment sites: the infraspinatus, supraspinatus, subscapularis and teres minor insertions. Functions of a normal shoulder were simulated, as well as those and of a shoulder with a posterosuperior rotator cuff tear before and after muscle transfers were simulated. Parameters such as active and passive moment-generating capacity, and the moment arm and fiber excursion ratio of the transferred muscle were analyzed.

Findings

All muscle transfers resulted in a large increase in shoulder external rotation strength. The latissimus dorsi was an external rotator after the transfer, but the fiber excursion ratio decreased accordingly. When the latissimus dorsi was transferred to the infraspinatus, supraspinatus or subscapularis insertion, it changed from extensor to flexor at the beginning of flexion. The flexion moment arm of the latissimus dorsi after the transfers was generally decreased. Shoulder abduction strength did not improve. Decrease in fiber excursion ratio during abduction and flexion was observed after the transfer. Side effects of the muscle transfers, such as the reduction of active adduction, extension and internal rotation of the shoulder, were explored.

Interpretation

A transfer to teres minor insertion was not recommended. Infraspinatus insertion was found to be a preferred attachment site in latissimus dorsi transfer, provided that the patient had a strong deltoid.     

Pathological muscle activation patterns in patients with massive rotator cuff tears, with and without subacromial anaesthetics

A mechanical deficit due to a massive rotator cuff tear is generally concurrent to a pain-induced decrease of maximum arm elevation and peak elevation torque. The purpose of this study was to measure shoulder muscle coordination in patients with massive cuff tears, including the effect of subacromial pain suppression. Ten patients, with MRI-proven cuff tears, performed an isometric force task in which they were asked to exert a force in 24 equidistant intervals in a plane perpendicular to the humerus. By means of bi-polar surface electromyography (EMG) the direction of the maximal muscle activation or principal action of six muscles, as well as the external force, were identified prior to, and after subacromial pain suppression. Subacromial lidocaine injection led to a significant reduction of pain and a significant increase in exerted arm force. Prior to the pain suppression, we observed an activation pattern of the arm adductors (pectoralis major pars clavicularis and/or latissimus dorsi and/or teres major) during abduction force delivery in eight patients. In these eight patients, adductor activation was different from the normal adductor activation pattern. Five out of these eight restored this aberrant activity (partly) in one or more adductor muscles after subacromial lidocaine injection. Absence of glenoid directed forces of the supraspinate muscle and compensation for the lost supraspinate abduction torque by the deltoideus leads to destabilizating forces in the glenohumeral joint, with subsequent upward translation of the humeral head and pain. In order to reduce the superior translation force, arm adductors will be co-activated at the cost of arm force and abduction torque. Pain seems to be the key factor in this (avoidance) mechanism, explaining the observed limitations in arm force and limitations in maximum arm elevation in patients suffering subacromial pathologies. Masking this pain may further deteriorate the subacromial tissues as a result of proximal migration of the humeral head and subsequent impingement of subacromial tissues.     

Comparative study of different tendon grasping techniques for arthroscopic repair of the rotator cuff

BACKGROUND: One cause of early failure of rotator cuff repairs is the pull out of the suture through the tendon. The aims of this study were to investigate the initial strength and failure mode of different tendon grasping techniques and to evaluate an alternative stitch proposed for arthroscopic repair of rotator cuff tendons. METHODS: Four different stitches were investigated: simple stitch, Mattress, modified Mason-Allen and simple stitch closed over a horizontal loop. The last stitch was proposed as an alternative to the modified Mason-Allen stitch since the former is simpler to sew arthroscopically than the latter. The experimental procedure was designed to assess the mechanical behaviour of the stitches. Tests were performed using sheep infraspinatus tendons. Two different non-absorbable sutures were used. Each specimen was preloaded with about 30 N and then loaded to failure. RESULTS: No significant difference was found in compliance among the four investigated stitches. Conversely, the tensile strength of the simple stitch and Mattress was lower than the tensile strength of the other two stitches, while no significant difference was observed between the modified Mason-Allen and the simple stitch closed over a horizontal loop. The maximum grasping power of these two 'reinforced' stitches was achieved only with the high-strength suture. INTERPRETATION: The simple stitch closed over a horizontal loop seems to be an attractive alternative to the modified Mason-Allen for arthroscopic repair of the rotator cuff and it seems recommendable instead of simple or Mattress stitches. The use of a high-strength suture would increase the tensile strength of the grasping in the case of good quality tendon tissue.