切开修补治疗肩袖损伤的临床分析

目的 分析肩袖损伤采用切开修复的临床疗效.方法 64例(64肩)肩袖损伤,按累及范围分单纯累及冈上肌腱34例,同时累及冈上肌腱和冈下肌腱23例,累及冈上肌腱和肩胛下肌腱7例,分别予以肌腱修补、止点重建,肌腱转位等治疗.结果 本组获随访1～5年,早期肩部疼痛及稳定性恢复最明显,单纯外伤性损伤早治疗效果满意.年龄、术前病程及肩袖撕裂大小与术后结果呈负相关.结论 切开修补治疗肩袖损伤能获得满意的效果,重视、提高肩袖损伤的诊断水平,做到早诊断、早治疗.     

关节镜下缝线桥技术治疗巨大肩袖撕裂的临床研究

目的探讨关节镜下缝线桥技术缝合巨大肩袖撕裂的临床疗效。 方法回顾分析2014年6月至2016年6月在广州市正骨医院收治并取得完整随访的38例采用关节镜下缝线桥技术修复的巨大肩袖撕裂患者的临床资料,排除无法取得随访、依从性差的患者,分析术前X线片、MRI检查,了解肩袖撕裂口大小、肩袖回缩程度、肌肉萎缩及脂肪浸润情况,应用SPSS 17.0统计学软件配对t检验对术前与术后半年随访时视觉模拟评分系统(VAS)评分和美国加州大学肩关节评分系统(UCLA)评分进行比较。 结果本组患者38例,男23例,女15例,平均年龄(66±6)岁,所有患者均获半年以上的随访,随访时间(12±5)月。所有患者在关节镜下均发现有2条或以上的肌腱撕裂,关节镜下见15例患者冈上肌腱和冈下肌腱撕裂,8例冈上肌、冈下肌和小圆肌腱撕裂,10例冈上肌腱、冈下肌腱撕裂和肩胛下肌腱撕裂,5例冈上肌腱和肩胛下肌腱撕裂。术前VAS评分为(6.7±1.6)分,术后6月随访时为(2.4±1.7)分,术前与术后6月随访的VAS评分差异均有统计学意义(t ＝10.123,P<0.01);术前UCLA评分为(7.9±1.2)分,术后6月随访时为(23.4±5.1)分,术前与术后6月随访的UCLA评分差异均有统计学意义(t ＝－18.979,P<0.01);术后的UCLA、VAS评分均明显升高。术后半年MR检查结果,5例患者出现小型再撕裂,裂口均<3 cm,术后再撕裂患者与无再撕裂患者的VAS评分和UCLA肩关节评分无明显统计学差异(P>0.05)。 结论关节镜下缝线桥技术修复巨大肩袖撕裂取得较好的短期疗效,是1种合理、有效的治疗方法。     

关节镜辅助背阔肌肌腱转位三角固定法治疗巨大后上肩袖撕裂

目的探讨关节镜辅助背阔肌肌腱转位三角固定法治疗巨大后上肩袖撕裂的疗效。方法采用关节镜辅助背阔肌肌腱转位三角固定法联合肩袖部分修补治疗11例巨大后上肩袖撕裂患者。采用Constant-Murley评分(CMS)、美国加州大学肩关节评分系统(UCLA)、美国肩肘外科评分(ASES)、肩袖生活质量问卷(RCQOL)评定临床疗效,采用VAS评分评价疼痛情况,并比较手术前后肩关节主动活动范围。结果患者均获得随访,时间9～21个月。末次随访时,CMS、UCLA、ASES、RC-QOL评分及肩关节主动活动范围均较术前增加,VAS评分较术前降低,差异均有统计学意义(P 0. 05)。结论关节镜辅助背阔肌肌腱转位三角固定法联合肩袖部分修补治疗能有效改善巨大后上肩袖撕裂患者的肩关节运动功能,缓解疼痛,增加肩关节主动活动范围,提升生活质量。     

关节镜下反向肩峰减压术在肩袖撕裂治疗中的应用

目的探讨关节镜下修复肩袖同时采用反向肩峰减压术治疗肩袖撕裂的疗效。方法 2012年11月-2015年1月,收治53例肩袖撕裂患者,于关节镜下进行肩袖修复同时行反向肩峰减压术。男38例,女15例;年龄47~61岁,平均53.4岁。摔伤36例,无明显外伤史17例。患者术前均有不同程度肩部疼痛,活动受限。疼痛视觉模拟评分(VAS)为(6.4±0.9)分,美国加州大学洛杉矶分校(UCLA)肩关节功能评分为(16.3±1.9)分。冈上肌远端撕裂41例,冈下肌远端撕裂12例;部分撕裂9例,全层撕裂44例;累及肌腱宽度1~3 cm,平均1.9 cm。伴肱二头肌长头肌腱炎31例,Bankart损伤5例,SLAP损伤2例。伴骨质疏松2例。结果术后患者切口均Ⅰ期愈合,无感染、神经损伤等并发症发生。49例获随访,随访时间12~35个月,平均22.8个月。术后42例患者肩关节疼痛症状缓解,7例术后3个月肩峰前缘附近存在疼痛,经对症处理后缓解。末次随访时,VAS评分为(0.5±0.6)分,与术前比较差异有统计学意义(t=40.565,P=0.000)。UCLA评分为(33.8±1.7)分,较术前显著提高,比较差异有统计学意义(t=—79.799,P=0.000);其中获优42例,良6例,可1例,优良率98.0%。结论关节镜下修复肩袖同时,采用反向肩峰减压术保留了喙肩弓等重要结构,术后肩关节功能恢复满意。     

关节镜下保留肩袖残端修复肩袖撕裂的疗效分析

目的 探讨关节镜下保留肩袖残端修复经肌腱不规则肩袖撕裂的手术方法与临床疗效。方法 回顾性分析自2019-03—2021-03诊治的7例经肌腱不规则肩袖撕裂,MRI显示肱骨大结节附着大量残余的肌腱组织,撕裂位于冈上肌肌腱的体部,撕裂方式不规则,残余的肌腱组织大小不一,采用关节镜下保留肌腱残端的双排缝合桥技术修复肩袖撕裂。结果 7例均获得随访,随访时间平均13.9(12～16)个月。术后所有患者无疼痛、关节肿胀及肩关节活动受限等不适主诉,术后复查肩关节MRI显示肩袖愈合良好,无肩袖再次撕裂发生。术后6周疼痛VAS评分为4～6分,平均5.7分;术后3个月疼痛VAS评分为1～3分,平均1.8分;术后6个月疼痛VAS评分为1～3分,平均1.1分;术后12个月疼痛VAS评分为0～1分,平均0.3分。术后6周肩关节功能UCLA评分为18～26分,平均23.3分;术后3个月肩关节功能UCLA评分为19～31分,平均25.0分;术后6个月肩关节功能UCLA评分为22～29分,平均26.7分;术后12个月肩关节功能UCLA评分为29～35分,平均32.1分。结论 对于肱骨大结节处残余较多肌腱的经肌腱不规则...     

关节镜下两种技术治疗肩袖关节侧部分撕裂的疗效比较

目的 探讨关节镜下经肌腱修补术和转全层撕裂修补术治疗肩袖关节侧部分撕裂的临床疗效。方法将46例肩袖关节侧部分撕裂患者采用随机数字表法分为经肌腱修补组(采用经肌腱修补术,23例)和转全层修补组(采用转全层撕裂修补术,23例)。比较两组末次随访时疼痛VAS评分、UCLA评分、ASES评分、肩关节活动度以及术后恢复活动时间。结果 患者均获得随访,时间12～22个月。术中及术后均无神经血管损伤、锚钉脱出及深部感染、肩关节功能明显受限等并发症发生。术后MRI和彩超复查肩袖肌腱再撕裂情况:转全层修补组发现2例,经肌腱修补组未发现。疼痛VAS评分、UCLA评分、ASES评分:末次随访时两组均较术前明显改善(P <0.05),两组间比较差异均无统计学意义(P> 0.05)。末次随访时肩关节活动度两组比较差异均无统计学意义(P>0.05)。术后恢复日常活动时间转全层修补组早于经肌腱修补组(P <0.05)。结论关节镜下经肌腱修补术和转全层撕裂修补术治疗肩袖关节侧部分撕裂,均可显著改善患者肩关节功能,但经肌腱修补术的患者术后肩关节功能恢复较慢。     

肩袖关节侧部分撕裂的手术方式及疗效分析

目的探讨和分析关节镜下修补肩袖关节侧部分撕裂(PASTA)的手术方法,包括穿肌腱修补法和转全层修补法治疗Ellman 3级肩袖关节侧部分撕裂的疗效及优缺点。 方法本次回顾性研究,分析了2015年3月至2017年6月期间因肩袖关节侧部分撕裂于南京医科大学第一附属医院骨科行手术治疗的全部患者,肩袖撕裂程度Ellman 3级(排除Ellman 1级和2级)的病例纳入本次研究,共42例。术中关节镜下根据滑囊侧残留肩袖组织的完整性、质地和张力等情况进行评估后,按手术修补方式分为穿肌腱修补组(肌腱组)20例,和转全层修补组(全层组)22例。肌腱组患者术中保留滑囊侧残留的肩袖组织,采用穿肌腱法修补肩袖;全层组患者术中清除滑囊侧残留的肩袖组织,直接转为全层撕裂,然后进行单排固定修补肩袖。术前、术后24 h及末次随访时对所有入组患者采用视觉模拟评分(VAS)进行疼痛评估。术前及术后末次随访时采用Constant-Murley肩关节评分(CSS)及洛杉矶加利福尼亚大学评分(UCLA)对所有入组患者进行肩关节功能评估。对比分析两组患者术后疗效及并发症发生情况,计数资料(性别、优势手和肩部外伤史等)采用χ²检验,同一组内术前术后计量资料对比采用配对t检验。 结果42例患者均获得随访,随访时间6～30个月,平均(16±7)个月。两组患者术后24 h及末次随访时VAS评分均较术前明显降低,差异具有统计学意义(P<0.05)。平均CSS评分从术前的(49.6±5.5)、(51.3±5.2)分别增加至(84.2±7.2)、(82.6±6.5),平均UCLA评分从术前的(18.4±3.2)、(17.7±2.3)分别增加至(32.1±2.2)、(31.2±2.2),差异具有统计学意义(P<0.05)。两组患者术后24 h时疼痛评分对比存在差异,具有统计学意义(t＝2.8, P<0.05)。比较两组患者末次随访时的疼痛评分及肩关节功能评分,差异均无统计学意义(P>0.05)。随访期间所有患者均未发生严重的术后并发症。 结论对于Ellman 3级的肩袖关节侧部分撕裂,关节镜下穿肌腱修补法和转全层修补法均可获得较满意的疗效,而穿肌腱修补法可以保留滑囊侧的肩袖组织,足印区的修补更加符合解剖基础,从而达到更好的腱骨愈合。在两种手术方法均可以熟练掌握的前提下,穿肌腱修补是更为理想的手术方式。     

肩关节镜下单排缝合技术治疗肩袖撕裂

目的探讨肩关节下南加州骨科研究所单排缝合技术(SCOI row)治疗大中型肩袖撕裂的疗效。 方法对2018年6月至2018年8月南方医科大学第五附属医院关节外科使用SCOI row技术缝合治疗的大中型肩袖撕裂患者进行回顾性研究。纳入中型或者大型肩袖撕裂,排除依从性较差合并其他损伤的患者,共纳入26例患者,男10例,女16例;平均年龄(64±5)岁。SCOI row技术即采用单排3线锚钉固定结合足印区周围扩多个骨髓孔技术。术前关节镜下测量肩袖撕裂范围为2～4 cm,其中冈上肌撕裂9例(34.6%),冈上肌、肩胛下肌撕裂11例(42.4%),冈上肌、冈下肌、肩胛下肌撕裂3例(11.5%),冈上肌、冈下肌撕裂3例(11.5%)。术后6个月通过MRI评判肩袖是否愈合,测量足印区新组织厚度,比较术前与术后6个月疼痛视觉模拟评分(VAS)及肩关节功能评分(UCLA)及肩关节主、被动活动度。术前与术后6个月的数据比较采用配对t检验。 结果所有患者术后获(7.9±1.6)个月随访。术前、术后6个月VAS评分分别为(6.5±1.7)、(2.1±0.8)分,差异有统计学意义(t ＝10.225,P<0.05)。UCLA评分术前为(12.7±3.8)、术后6个月(31.1±1.6)分,差异有统计学意义(t ＝-3.066, P<0.05)。术后6个月足印区新组织厚度平均为(7.08±0.28)mm。术后6个月患者被动前屈、主动前屈、被动外展、主动外展、中立位被动外旋、中立位主动外旋活动度分别为(162.1±10.5)°、(155.3±38.5)°、(138.2±29.3)°、(130.4±22.4)°、(26.2±8.2)°、(15.3±7.3)°,均较术前明显提高(t ＝-7.913、-11.263、-8.286、-7.285、-11.734、-4.891,均为P <0.05)。术后6个月MRI显示肩袖撕裂足印区完全愈合为24例,再次撕裂2例,愈合率92.3%。 结论SCOI row技术缝合肩袖撕裂通过MRI评判愈合较高,肩关节功能恢复较好,疼痛缓解,是一种治疗肩袖撕裂的有效方法。     

肩袖部分撕裂的诊断和治疗

目的探讨肩袖部分撕裂的诊断和手术方法。方法1999年4月~2004年1月,我所对14例肩袖部分撕裂进行手术治疗。术前均拍摄肩关节正位和冈上肌出口位X线片,11例B超检查,14例MR I或MRA检查。5例行肩峰下间隙减压及肩袖清理术;9例行肩峰下间隙减压及肩袖修复术。采用UCLA肩关节评分标准进行评价。结果滑囊侧部分撕裂7例,关节侧部分撕裂7例。14例随访1~6年,平均38个月,UCLA评分由术前(15.9±3.9)分升至术后(30.9±5.2)分(t=15.000,P=0.000)。良13例,差1例;13例满意。结论关节镜检查是诊断肩袖部分撕裂的可靠方法。肩袖修复术是治疗肩袖部分撕裂的有效方法。关节镜下手术创伤小、恢复快。     

关节镜下肩袖缝合术治疗肩袖全层撕裂的中期疗效观察

目的 探讨关节镜下肩袖缝合术治疗肩袖全层撕裂的手术方法和中期效果.方法 2002年12月至2007年5月对35例肩袖全层撕裂患者行关节镜下肩袖缝合术,30例获得随访,其中男性15例,女性15例;年龄31～74岁,平均55.6岁.左肩3例,右肩27例.全部病例行肩峰下滑囊切除及肩峰成形术.肩袖修复方式:19例应用缝合锚钉行肩袖止点重建,11例联合应用断端缝合及缝合锚钉技术.16例行单排缝合,14例行双排缝合.2012年6月对所有患者进行随访,分别在术前和随访时采用UCLA肩关节评分标准进行评价,评分结果行配对t检验.结果 小型撕裂3例,中型撕裂22例,大型撕裂3例,巨大撕裂2例,随访时间5 ～ 10年,平均78.5个月.UCLA评分从术前的(14.2±3.1)分增至术后(33.6±2.1)分(t=-37.154,P=0.000).其中疼痛评分平均为(2.5±0.9)分比(9.5±1.0)分(t=-24.466,P=0.000),功能评分平均为(4.5±1.5)分比(9.4±1.1)分(t=-18.500,P=0.000),主动前屈角度评分平均为(3.3±1.6)分比(4.9±0.2)分(t=-5.614,P=0.000),前屈肌力评分平均为(3.9±0.5)分比(4.7±0.4)分(t=-6.591,P=0.000),差异均有统计学意义.根据术后随访UCLA评分,优19例,良11例.单排缝合患者术前平均(13.0±3.2)分,术后平均(33.6±1.7)分.双排缝合患者术前平均(15.6±2.4)分,术后平均(33.6±2.6)分,两组患者手术前后评分差异均有统计学意义(t=-33.071和-26.455,P＜0.05).所有患者对手术效果表示满意.结论 关节镜下肩袖缝合治疗肩袖全层撕裂创伤小、恢复快,中期效果令人满意.单排缝合与双排缝合的效果均令人满意.术中应正确识别撕裂的形状,充分松解粘连并采用恰当的缝合方式.     

Arthroscopic repair of full-thickness tears of the supraspinatus: does the tendon really heal?

BACKGROUND: Good functional results have been reported for arthroscopic repair of rotator cuff tears, but the rate of tendon-to-bone healing is still unknown. Our hypothesis was that arthroscopic repair of full-thickness supraspinatus tears achieves a rate of complete tendon healing equivalent to those reported in the literature with open or mini-open techniques. METHODS: Sixty-five consecutive shoulders with a chronic full-thickness supraspinatus tear were repaired arthroscopically in sixty-five patients with use of a tension-band suture technique. Patients ranged in age from twenty-nine to seventy-nine years. The average duration of follow-up was twenty-nine months. Fifty-one patients (fifty-one shoulders) had a computed tomographic arthrogram, and fourteen had a magnetic resonance imaging scan, performed between six months and three years after surgery. All patients were assessed with regard to function and the strength of the shoulder elevation. RESULTS: The rotator cuff was completely healed and watertight in forty-six (71%) of the sixty-five patients and was partially healed in three. Although the supraspinatus tendon did not heal to the tuberosity in sixteen shoulders, the size of the persistent defect was smaller than the initial tear in fifteen. Sixty-two of the sixty-five patients were satisfied with the result. The Constant score improved from an average (and standard deviation) of 51.6 +/- 10.6 points preoperatively to 83.8 +/- 10.3 points at the time of the last follow-up evaluation (p < 0.001), and the average University of California at Los Angeles score improved from 11.5 +/- 1.1 to 32.3 +/- 1.3 (p < 0.001). The average strength of the shoulder elevation was significantly better (p = 0.001) when the tendon had healed (7.3 +/- 2.9 kg) than when it had not (4.7 +/- 1.9 kg). Factors that were negatively associated with tendon healing were increasing age and associated delamination of the subscapularis or infraspinatus tendon. Only ten (43%) of twenty-three patients over the age of sixty-five years had completely healed tendons (p < 0.001). CONCLUSIONS: Arthroscopic repair of an isolated supraspinatus detachment commonly leads to complete tendon healing. The absence of healing of the repaired rotator cuff is associated with inferior strength. Patients over the age of sixty-five years (p = 0.001) and patients with associated delamination of the subscapularis and/or the infraspinatus (p = 0.02) have significantly lower rates of healing.     

Mode of failure for rotator cuff repair with suture anchors identified at revision surgery

Rotator cuff tears are a common cause of shoulder pain and dysfunction. After surgical repair, there is a significant re-tear rate (25%-90%). The aim of this study was to determine the primary mode of mechanical failure for rotator cuffs repaired with suture anchors at the time of revision rotator cuff repair. We prospectively followed 342 consecutive torn rotator cuffs, repaired by a single surgeon using suture anchors and a mattress-suturing configuration. Of those shoulders, 21 (6%) subsequently underwent a revision rotator cuff repair by the original surgeon, and 1 underwent a second revision repair. Intraoperative findings, including the mode of failure, were systematically recorded at revision surgery and compared with the findings at the primary repair. In addition, 81 primary rotator cuff repairs had a radiographic and fluoroscopic evaluation at a mean of 37 weeks after repair to assess for any loosening or migration of the anchors. At revision rotator cuff repair, the predominant mode of failure was tendon pulling through sutures (19/22 shoulders) (P <.001). Two recurrent tears occurred in a new location adjacent to the previous repair, and one anchor was found loose in the supraspinatus tendon. The mean size of the rotator cuff tear was larger at the revision surgery (P =.043), the tendon quality ranked poorer (P =.013), and the tendon mobility decreased (P =.002), as compared with the index procedure. The radiographs and fluoroscopic examination showed that all 335 anchors in 81 patients were in bone. Rotator cuff repairs with suture anchors that underwent revision surgery failed mechanically by three mechanisms, the most common of which was tendon pulling through sutures. This suggests that the weak link in rotator cuff repairs with suture anchors and horizontal mattress sutures, as determined at revision surgery, is the tendon-suture interface.     

Rotator cuff repair with a novel mesh suture: An ex vivo assessment of mechanical properties

Surgical repair is a common treatment for rotator cuff tear; however, the retear rate is high. A high degree of suture repair strength is important to ensure rotator cuff integrity for healing. The purpose of this study was to compare the mechanical performance of rotator cuffs repaired with a mesh suture versus traditional polydioxanone suture II and FiberWire sutures in a canine in vitro model. Seventy‐two canine shoulders were harvested. An infraspinatus tendon tear was created in each shoulder. Two suture techniques—simple interrupted sutures and two‐row suture bridge—were used to reconnect the infraspinatus tendon to the greater tuberosity, using three different suture types: Mesh suture, polydioxanone suture II, or FiberWire. Shoulders were loaded to failure under displacement control at a rate of 20 mm/min. Failure load was compared between suture types and techniques. Ultimate failure load was significantly higher in the specimens repaired with mesh suture than with polydioxanone suture II or FiberWire, regardless of suture technique. There was no significant difference in stiffness among the six groups, with the exception that FiberWire repairs were stiffer than polydioxanone suture II repairs with the simple interrupted technique. All specimens failed by suture pull‐out from the tendon. Based on our biomechanical findings, rotator cuff repair with the mesh suture might provide superior initial strength against failure compared with the traditional polydioxanone suture II or FiberWire sutures. Use of the mesh suture may provide increased initial fixation strength and decrease gap formation, which could result in improved healing and lower re‐tear rates following rotator cuff repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:987–992, 2018.

     

In situ transtendon repair outperforms tear completion and repair for partial articular-sided supraspinatus tendon tears

This biomechanical study compared 2 repair techniques for high-grade, partial, articular-sided supraspinatus tendon tears of the rotator cuff: transtendon in situ repair and tear completion with repair. Standardized, 50% partial, articular-sided supraspinatus lesions were created in 10 pairs of matched fresh, frozen cadaveric shoulders: 10 underwent partial lesion repair with an in situ transtendon technique using 2 suture anchors. In the contralateral 10 shoulders, the partial lesion was converted to a full-thickness tear and repaired with a double-row technique, using 4 suture anchors. Cyclic loading to failure of the supraspinatus tendon was performed using a material testing machine. Gap formation was measured for each rotational position and each incremental load. The in situ transtendon repair had statistically significant less gapping (P = .0001) and higher mean ultimate failure strength (P = .0011) than the double-row repair. In situ transtendon repair was biomechanically superior to tear completion for partial, articular-sided supraspinatus tears.     

The outcome and structural integrity of arthroscopic rotator cuff repair with use of the double-row suture anchor technique

BACKGROUND: The reported rate of failure after arthroscopic rotator cuff repair has varied widely. The influence of the repair technique on the failure rates and functional outcomes after open or arthroscopic rotator cuff repair remains controversial. The purpose of the present study was to evaluate the functional and anatomic results of arthroscopic rotator cuff repairs performed with the double-row suture anchor technique on the basis of computed tomography or magnetic resonance imaging arthrography in order to determine the postoperative integrity of the repairs. METHODS: A prospective series of 105 consecutive shoulders undergoing arthroscopic double-row rotator cuff repair of the supraspinatus or a combination of the supraspinatus and infraspinatus were evaluated at a minimum of two years after surgery. The evaluation included a routine history and physical examination as well as determination of the preoperative and postoperative strength, pain, range of motion, and Constant scores. All shoulders had a preoperative and postoperative computed tomography arthrogram (103 shoulders) or magnetic resonance imaging arthrogram (two shoulders). RESULTS: There were thirty-six small rotator cuff tears, forty-seven large isolated supraspinatus or combined supraspinatus and infraspinatus tendon tears, and twenty-two massive rotator cuff tears. The mean Constant score (and standard deviation) was 43.2+/-15.1 points (range, 8 to 83 points) preoperatively and 80.1+/-11.1 points (range, 46 to 100 points) postoperatively. Twelve of the 105 repairs failed. Intact rotator cuff repairs were associated with significantly increased strength and active range of motion. CONCLUSIONS: Arthroscopic repair of a rotator cuff tear with use of the double-row suture anchor technique results in a much lower rate of failure than has previously been reported in association with either open or arthroscopic repair methods. Patients with an intact rotator cuff repair have better pain relief than those with a failed repair. After repair, large and massive rotator cuff tears result in more postoperative weakness than small tears do.     

Restoration of anterior–posterior rotator cuff force balance improves shoulder function in a rat model of chronic massive tears

The rotator cuff musculature imparts dynamic stability to the glenohumeral joint. In particular, the balance between the subscapularis anteriorly and the infraspinatus posteriorly, often referred to as the rotator cuff “force couple,” is critical for concavity compression and concentric rotation of the humeral head. Restoration of this anterior–posterior force balance after chronic, massive rotator cuff tears may allow for deltoid compensation, but no in vivo studies have quantitatively demonstrated an improvement in shoulder function. Our goal was to determine if restoring this balance of forces improves shoulder function after two‐tendon rotator cuff tears in a rat model. Forty‐eight rats underwent detachment of the supraspinatus and infraspinatus. After four weeks, rats were randomly assigned to three groups: no repair, infraspinatus repair, and two‐tendon repair. Quantitative ambulatory measures including medial/lateral forces, braking, propulsion, and step width were significantly different between the infraspinatus and no repair group and similar between the infraspinatus and two‐tendon repair groups at almost all time points. These results suggest that repairing the infraspinatus back to its insertion site without repair of the supraspinatus can improve shoulder function to a level similar to repairing both the infraspinatus and supraspinatus tendons. Clinically, a partial repair of the posterior cuff after a two‐tendon tear may be sufficient to restore adequate function. An in vivo model system for two‐tendon repair of massive rotator cuff tears is presented. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1028–1033, 2011     

Atrophy of the rotator cuff muscles and site of cuff tears

We determined the relationship between the site of rotator cuff tears and atrophy of the cuff muscles. 28 shoulders (28 patients) had rotator cuff tears: 19 isolated tears of the supraspinatus tendon (isolatedtear group) and 9 combined tears of the supraspinatus and infraspinatus tendons (combined-tear group). The cross-sectional area of the subscapularis, supraspinatus, the infraspinatus and teres minor muscles in the coronal oblique MR images were measured before and after surgery. Although we found no difference in tear size, the cross-sectional areas of the muscles were smaller in the combined-tear group than in the isolated-tear group. We conclude that atrophy of the supraspinatus and infraspinatus muscles also depends on the site of the tear.     

Atrophy of the rotator cuff muscles and site of cuff tears

We determined the relationship between the site of rotator cuff tears and atrophy of the cuff muscles. 28 shoulders (28 patients) had rotator cuff tears: 19 isolated tears of the supraspinatus tendon (isolated-tear group) and 9 combined tears of the supraspinatus and infraspinatus tendons (combined-tear group). The cross-sectional area of the subscapularis, supraspinatus, the infraspinatus and teres minor muscles in the coronal oblique MR images were measured before and after surgery. Although we found no difference in tear size, the cross-sectional areas of the muscles were smaller in the combined-tear group than in the isolated-tear group. We conclude that atrophy of the supraspinatus and infraspinatus muscles also depends on the site of the tear.     

Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles.

A rotator cuff tear causes morphologic changes in rotator cuff muscles and tendons and reduced shoulder strength. The mechanisms by which these changes affect joint strength are not understood. This study's purpose was to empirically determine rotation moment arms for subregions of supraspinatus, infraspinatus, and for teres minor, and to test the hypothesis that subregions of the cuff tendons increase their effective moment arms through connections to other subregions. Tendon excursions were measured for full ranges of rotation on 10 independent glenohumeral specimens with the humerus abducted in the scapular plane at 10 and 60 degrees . Supraspinatus and infraspinatus tendons were divided into equal width subregions. Two conditions were tested: tendon divided to the musculotendinous junction, and tendon divided to the insertion on the humerus. Moment arms were determined from tendon excursion via the principle of virtual work. Moment arms for the infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly greater when the tendon was only divided to the musculotendinous junction versus division to the humeral head. Moment arms across subregions of infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly different. A difference in teres minor moment arm was not found for the two cuff tendon conditions. Moment arm differences between muscle subregions and for tendon division conditions have clinical implications. Interaction between cuff regions could explain why some subjects retain strength after a small cuff tear. This finding helps explain why a partial cuff repair may be beneficial when a complete repair is not possible. Data presented here can help differentiate between cuff tear cases that would benefit from cuff repair and cases for which cuff repair might not be as favorable.