双排缝合锚钉治疗老年陈旧性肱骨大结节撕脱骨折

目的探讨应用缝合锚钉治疗老年陈旧性肱骨大结节撕脱骨折的临床疗效。方法将近排缝合锚钉置入肱骨断裂面与冈上肌的最近边缘,解剖学缝合骨块与冈上肌交界的肩袖止点。于肱骨断裂面的远端置入远排缝合锚钉,将其尾线与近排锚钉尾线打结。结果 5例获随访8~24个月,骨折块得到解剖学复位及骨性愈合。结论采用双排缝合锚钉治疗老年陈旧性肱骨大结节撕裂骨折可有效地限制冈上肌对骨块的牵拉,固定牢靠,且利于早期恢复锻炼,疗效佳。     

肱骨外展动作中肩袖生物力学的有限元分析

目的构建肩关节有限元模型，用于分析肩袖生物力学。 方法采集1名26岁健康男性志愿者右肩CT、MRI数据，构建肩关节有限元模型，包含肩胛骨、肱骨、锁骨，以及肩袖肌群（冈上肌、冈下肌、小圆肌、肩胛下肌）。模拟肱骨在肩胛骨平面外展，分析肩袖肌肉应力变化。 结果肱骨在肩胛骨平面外展0°~30°过程中，各组肌腱与肱骨头连接处的应力均增大。冈上肌腱应力变化速率较快；肩胛骨前方的肩胛下肌对比肩胛骨后方的冈下肌-小圆肌，两组肌腱的应力变化较为同步。当肱骨在肩胛骨平面外展30°时，冈上肌腱、肩胛下肌腱及冈下肌腱-小圆肌腱与肱骨头连接面的平均应力分别为7.894 8、4.721 7、3.768 8 Mpa，冈上肌腱关节面与滑囊面结点平均应力分别为7.931 4、4.099 0 Mpa。冈上肌腱的关节面与滑囊面应力有明显差异，应力差值随肱骨在肩胛骨平面外展而增大，造成的剪切力可造成冈上肌腱撕裂。 结论肩袖对肩关节的活动与稳定性有重要作用，其受力特点易引起肩袖损伤。     

单排和双排肩袖缝合桥力学研究

目的:从生物力学的角度比较分析单排带线锚钉固定修复肩袖损伤和双排缝合桥固定修复肩袖损伤的力学差异。方法:将健康成年人肩关节的CT扫描数据依次导入Mimics,Geomagics和Hypermesh中进行两种修复模型的逆向重建、材料赋属和网格划分等操作,并设计出冈上肌撕裂的情况,处理完毕后将其导入ABAQUS软件中对其施加载荷与边界条件,模拟锚钉固定修复完成后肩关节前屈15°、30°,内旋15°、30°这4种工况。比较两种修复模型在4种工况下肩袖冈上肌,带线锚钉的应力变化。结果:两种前屈工况下双排缝合桥固定模型中冈上肌所受应力值分别比单排固定修复模型中冈上肌所受应力值小8.3%和12%。两种内旋工况下,双排缝合桥固定模型中冈上肌所受应力值分别比单排固定修复模型中冈上肌所受应力值小47%和48%。结论:双排4枚锚钉之间的“负荷共享”效应使应力分布更为分散,增大了冈上肌与肱骨之间的接触面积,减小了锚钉的受力,避免了严重的应力集中现象,从生物力学角度解释了双排缝合桥固定方法的优势。     

带线锚钉固定技术修复肩袖损伤生物力学研究

在肩袖肌肉中,冈上肌起着外展肩关节的作用。Inoue等[1]进行有限元分析,证实了冈上肌在肩关节运动起着重要的作用。但冈上肌也是肩袖中容易损伤撕裂的肌肉之一,双排带线锚钉固定修复法因其能增加冈上肌与肱骨头的接触面积,能降低肌肉再次损伤的风险而受到临床的亲睐,但有关该方法的生物力学分析还比较少。本研究分别建立可用于有限元分析的单/双排带线锚钉固定修复肩袖损伤的肩关节模型,比较两种方法修复后肩关节外展状态下冈上肌的应力变化,从生物力学的角度探讨双排带线锚钉固定法的优越性。     

基于骨肌多体动力学前臂旋前旋后的有限元分析

目的探讨前臂旋前旋后运动的肌力变化以及肱骨应力、位移的生物力学特性。 方法根据Dicom数据在MIMICS中重建三维肱骨并在Hypermesh中划分网格和材料赋值。采用志愿者的身高、体重数据在AnyBody骨骼肌肉系统中建立个性化上肢的骨骼肌肉模型,模拟前臂旋前旋后运动,导出旋前旋后运动过程中的肌力等边界条件,将此数据作为肱骨有限元分析的边界条件。最后在Abauqus中行肱骨应力、位移大小的分析。 结果前臂0°～90°旋前运动时主要是旋前圆肌、旋前方肌发挥作用,旋前圆肌约90°时肌肉力最大,旋前方肌约40°时肌肉力最大。当前臂0°～90°旋后运动时主要是旋后肌、肱二头肌发挥作用,二者肌肉力在旋后约90°时最大。旋前运动约90°时肱骨受到的应力、位移最大,而旋后运动约10°时肱骨受到的应力、位移最大。应力大致在肱骨中下1/3处集中,而位移集中在肱骨的中部及远端,且以肱骨远端最为明显。 结论利用AnyBody骨骼肌肉系统成功模拟了前臂旋前旋后运动并与有限元分析联动,在肌力加载下分析肱骨应力、位移。肱骨中下段是骨折的好发部位。     

骨质疏松性肱骨近端骨折PMMA骨水泥强化螺钉钢板固定的有限元分析

目的：借助有限元分析的方法探讨肱骨近端聚甲基丙烯酸甲酯（polymethyl methacrylate,PMMA）骨水泥强化螺钉钢板固定对骨质疏松性肱骨近端骨折内固定稳定性的影响。方法：制作肱骨近端2部分骨折伴干骺端骨缺损的不稳定肱骨近端骨折数字化模型,分别建立肱骨近端骨水泥强化螺钉钢板固定及普通螺钉钢板固定的有限元模型,分析螺钉周围松质骨应力、整体刚度、钢板最大应力及螺钉最大应力。结果：肱骨近端骨水泥强化螺钉钢板固定的头端6枚螺钉周围松质骨最大应力分别为：1号钉1.07 MPa,2号钉0.43 MPa,3号钉1.16 MPa,4号钉0.34 MPa,5号钉1.99 MPa,6号钉1.57 MPa,普通螺钉钢板固定为：1号钉2.68 MPa,2号钉0.67 MPa,3号钉4.37 MPa,4号钉0.75 MPa,5号钉3.30 MPa、6号钉2.47 MPa。两组模型的整体刚度分别为：骨水泥结构448 N/mm、普通结构434 N/mm。钢板的最大应力均出现在结合孔：骨水泥结构701 MPa、普通结构420 MPa。螺钉的最大应力均出现在4号钉的尾端：骨水泥结构284 MPa、普通结构...     

老年Neer Ⅵ型肱骨近端骨折合并肩关节后脱位的手术治疗

[目的]探讨钢板固定、缺损处植骨结合锚钉修补肩袖治疗肱骨近端Neer Ⅵ型骨折合并肩关节后脱位。[方法]采用扩大的肩峰下经三角肌入路,暴露后脱位肱骨头及关节囊,松解周围嵌顿软组织,持续牵引下拨肱骨头,复位肩关节,复位撕脱大小结节,克氏针临时固定,PHILOS钢板固定,肱骨头下骨折处植入同种异体骨给予支撑。置入锚钉,依次修复撕裂的肩胛下肌、冈上肌腱。[结果]本组患者平均手术时间(110±25)min,术中平均出血量(120±25)ml,平均住院时间17 d。22例患者均获得随访,随访时间1~15个月,19例骨性愈合,2例出现肱骨头缺血性坏死,1例出现骨折不愈合并断端吸收。Neer评级:优9例,良10例,可1例,差2例,优良率86.3%。[结论]对于肱骨近端骨折合并肱骨头后脱位的老年患者,采用PHILOS钢板固定、骨折缺损处植骨结合锚钉修复肩袖治疗固定牢固,骨折愈合良好,肩关节功能重建良好。     

肱骨近端骨折3种不同固定方式重建内侧柱的有限元分析

目的采用有限元分析肱骨近端骨折锁定钢板联合内侧支撑螺钉、锁定钢板联合腓骨支撑及外侧锁定钢板联合内侧钢板重建内侧柱3种内固定模型的生物力学稳定性。方法选取1名健康女性志愿者进行肱骨近端CT扫描,按照肱骨解剖颈下5 mm截骨,建立肱骨近端内侧柱缺失型骨折模型,按不同内固定方式分为PC组、PF组、PP组。PC0组单纯应用肱骨近端锁定钢板,PC1组采用肱骨内侧支撑螺钉联合肱骨近端锁定钢板固定。PF0组单纯采用锁定钢板联合腓骨支撑,PF1组置入内侧支撑螺钉并使用锁定钢板联合腓骨支撑。PP0组单纯应用外侧锁定钢板联合内侧钢板,PP1组置入内侧支撑螺钉锁定钢板联合内侧钢板,采用三维有限元法分析间接暴力状态下不同分组模型的生物力学稳定性。结果PP组的肱骨应力明显小于PC、PF组,PP组相对位移最小,PC组相对位移最大;且应用内侧支撑螺钉的各组肱骨最大等效应力、肱骨相对位移分别小于未应用内侧支撑螺钉组。PC组钢板最大等效应力最大,PP组钢板最大等效应力最小;且应用内侧支撑螺钉的各组的钢板最大等效应力分别大于未应用内侧支撑螺钉组。结论外侧锁定钢板联合内侧钢板重建内侧柱较锁定钢板联合内侧支撑螺钉、锁定钢板联合异体腓骨重建内侧柱相比均有明显的力学优势,而锁定钢板联合异体腓骨重建内侧柱力学稳定性则优于锁定钢板联合内侧柱支撑螺钉;同时行内侧支撑螺钉的内固定模型均比未行内侧支撑螺钉的内固定模型有更好的力学稳定性。     

有限接触式带锁髓内钉的有限元分析及临床应用

[目的]设计、制造一种可与人工表面关节结合的有限接触式股骨髁上型带锁髓内钉,构成人工半膝关节系统,用于提高儿童保肢手术效果。[方法]运用有限元方法对髓内钉锁钉不同置入角度(锁钉与髓内钉横断面的夹角)0°、15°、30°、45°、60°条件下骨、髓内钉及锁钉和整体结构进行应力分析。[结果]有限元分析(FEA)结果显示,锁钉以15°角置入时,骨、髓内钉及锁钉所受最大应力为最小,应力分布也较其它角度均匀。在0°角时,骨的最大应力较15°、30°和45°时大。随着穿钉角度的增大,近端锁钉最大应力增加,远端锁钉最大应力减小。[结论]有限接触式髓内钉减少了对骨原有生物环境的破坏,可与人工表面关节结合运用于异体骨关节移植,有较好的临床应用价值。     

预防股骨颈骨折空心钉内固定术后股骨颈短缩空心螺纹钉优化选择的有限元分析

目的: 运用有限元分析法比较采用不同数量全螺纹空心钉在不同置钉位置内固定治疗Pauwels Ⅱ型股骨颈骨折,预防术后颈短缩的生物力学特性。方法: 选取健康老年女性志愿者1名,年龄55岁,体重70 kg,身高165 cm。采用CT扫描,获取右侧股骨数据,在三维建模软件分别建立Pauwels Ⅱ型股骨颈骨折模型、全螺纹空心钉和半螺纹空心钉模型。按全螺纹空心钉数量和置入呈倒三角分布位置分为8组骨折内固定模型:3枚半螺纹钉组、1枚前上方全螺纹钉加2枚半螺纹钉组,1枚后上方全螺纹钉加2枚半螺纹钉组,1枚下方全螺纹钉加2枚半螺纹钉组,1枚前上方半螺纹钉加2枚全螺纹钉组,1枚后上方半螺纹钉加2枚全螺纹钉组,1枚下方半螺纹钉加2枚全螺纹钉组,3枚全螺纹钉组。在有限元分析软件中分别加载同样载荷,比较分析各组的内固定物的应力分布及应力峰值、股骨近端应力分布及应力峰值、骨折断端切面的应力分布及应力峰值、内固定物位移峰值,并比较术后股骨颈长度。结果: 各组的内固定应力主要集中于骨折线处,且均位于下方螺钉的底部,应力峰值分别为239.71、213.44、199.37、230.82、201.63、215.72、185.65、192.64 MPa;各组股骨近端所受的应力主要集中于转子下内侧区域,应力峰值分别为269.48、241.62、249.43、269.69、271.60、346.64、236.97、439.62 MPa;骨折断端切面的应力主要集中于半螺纹钉道周围,全螺纹钉道周围应力相对较小,各组应力峰值分别为149.12、143.04、140.47、139.63、139.81、130.07、117.77、57.89 MPa;内固定物的位移基本沿股骨颈轴线方向,位移分布集中于螺钉尖端,各组螺钉位移峰值分别为5.52、5.43、5.32、5.17、5.05、5.13、5.28、5.04 mm;各组股骨颈长度分别为74.69、74.72、74.70、74.70、74.72、74.70、74.72、74.74 mm。结论: 呈倒三角分布的前上方1枚半螺纹空心钉联合2枚全螺纹空心钉的置钉方案既可以满足促进股骨颈愈合的滑动加压作用,保证股骨近端稳定性,又能减少术后股骨颈短缩程度,有利于维持术后股骨颈长度,降低术后股骨颈短缩导致髋关节功能障碍的发生率,为临床空心钉治疗股骨颈骨折提供了新的优化置钉方案。     

Reprint of: The Deadman Theory of Suture Anchors: Observations Along a South Texas Fence Line

Suture anchors are being increasingly reported as a means of fixation of torn rotator cuff tendons to bone. The author has developed a mechanical model for the suture anchor–rotator cuff construct based on an analogy to the deadman system used to stabilize a corner fence post. Using this model, one can demonstrate a mechanically favorable angle of insertion of the suture anchor (θ₁) such that the anchor's pullout strength is increased at low angles of θ₁. In addition, the angle that the suture makes with the direction of pull of the rotator cuff (θ₂) has a direct effect on tension in the suture. A low angle of θ₂ minimizes the total tension in the suture, thereby minimizing the chance of suture breakage.     

Increasing the insertion depth of suture anchors for rotator cuff repair does not improve biomechanical stability

The purpose of this study was to evaluate whether deeper-than-recommended insertion of a suture anchor within the rotator cuff footprint of human cadaveric humeri affects fixation characteristics. Metallic 5-mm screw-in anchors loaded with a single No. 2 suture were placed in the infraspinatus footprint of 8 human cadaveric humeri at standard and deep depths. Specimens were cyclically loaded from 10 to 45 N for 500 cycles and then loaded to failure. Cylic displacement, failure load, and failure mode were compared. All deep anchors became flush within a few cycles, and both anchor depths displaced and rotated at the bone surface. Displacement of the deep anchors was significantly greater than that of standard anchors. There was no difference in failure load. Cyclic testing showed significant displacement, regardless of anchor position, possibly leading to gap formation of the repair. Deep placement of suture anchors for increased purchase caused greater displacement and is not recommended.     

A New “Trapdoor technique” for Fixation of Displaced Greater Tuberosity Fractures of the Shoulder

Isolated greater tuberosity fractures of the proximal humerus are frequently displaced posteriorly and superiorly by the pull of the rotator cuff. This displacement can lead to a decline in function if left untreated. Traditionally these fractures have been treated surgically using screw fixation. On occasions this metalwork can remain prominent and potentially cause impingement. We present a new surgical “trapdoor” technique for fixation of isolated greater tuberosity fractures which can avoid these problems and be utilised either open or arthroscopically. Following reduction of the isolated greater tuberosity fragment, two double loaded metal screw in anchors are placed through stab incisions in the rotator cuff at the bone-tendon interface and secured into the humeral head. A suture from each of the anchors is tied together to secure the tuberosity fragment proximally and a suture-less anchor is inserted distal to the fracture site forming an inverted triangle. The remaining sutures are placed through the suture-less anchor and tensioned independently. As the sutures are tied and snugged tight, the distal aspect of the fracture reduces, thus closing the “trapdoor.” This is a newly described versatile technique that can be used regardless of the size and comminution of the tuberosity fragment and can be performed either open or arthroscopically. It avoids the problems of metalwork prominence and irritation and the use of the suture-less anchor allows independent tensioning of the sutures to ensure adequate fracture reduction.     

The deadman theory of suture anchors: observations along a South Texas fence line

Suture anchors are bing increasingly reported as a means of fixation of torn rotator cuff tendons to bone. The author has developed a mechanical model for the suture anchor-rotator cuff construct based on an analogy to the deadman system used to stabilize a corner fence post. Using this model, one can demonstrate a mechanically favorable angle of insertion of the suture anchor (θ₁) such that the anchor's pullout strength is increased at low angles of θ₁. In addition, the angle that the suture makes with the direction of pull of the rotator cuff (θ₂) has a direct effect on tension in the suture. A low angle of θ₂ minimizes the total tension in the suture, thereby minimizing the chance of suture breakage.     

The measurement of bone mineral density of bilateral proximal humeri using DXA in patients with unilateral rotator cuff tear

Summary

We propose that the measurement of the bone mineral density (BMD) of the proximal humerus be standardized using the dual energy X-ray absorptiometry (DXA) in patients supposed to undergo rotator cuff repair surgery as well as those with the fracture of the proximal humerus as the BMD of the proximal humerus is decreased in these patients.

Introduction

We propose that the measurement of the BMD of the proximal humerus be standardized using the DXA in patients who are supposed to undergo rotator cuff repair surgery as well as those with the fracture of the proximal humerus.

Methods

We conducted the prospective study in 213 patients with unilateral rotator cuff tear but without contralateral shoulder pain or disease. In these patients, we preoperatively measured the BMD of the bilateral proximal humeri with a repeat measurement in 20 patients. We predefined three regions of interest (ROIs) in the proximal humerus with the consideration of the rotator cuff repair surgery as well as proximal humeral fractures.

Results

The measurement of the BMD of the proximal humerus using the DXA showed excellent reliability (intraclass correlation coefficient?>?.90). BMD values of all three ROIs in the affected shoulder were significantly lower than those in asymptomatic shoulder (all p?p?Conclusions It is imperative that the bone quality of the proximal humerus be accurately evaluated prior to surgery in patients who are supposed to undergo rotator cuff repair using suture anchors as well as in those with proximal humeral fractures. This is because the BMD of the proximal humerus is decreased in these patients.     

Use of direct introduction of allograft anchors for rotator cuff repair

Allograft anchors that can be inserted directly through the greater tuberosity were developed, tested, and used clinically for rotator cuff repair. Mechanical strength testing was performed, and allograft anchors were used in 63 consecutive procedures by a single surgeon. The insertion technique involved directly impacting the allograft anchor through the greater tuberosity without drilling a hole in the bone. Results of mechanical testing showed strengths comparable with those of other anchors (155.8 N), and the anchors locked consistently. This direct insertion technique saves time and procedural steps over traditional anchor insertion techniques while using an allograft anchor that reincorporates into host bone.     

Anatomy of the supraclavicular fossa portal in shoulder arthroscopy

Because of the need for a third portal for operative procedures during glenohumeral joint arthroscopy, we studied the anatomy of the supraclavicular fossa portal with the humerus in various degrees of abduction and the trochar placed at various angles. Our purpose was to establish a "safe zone" of introduction that would avoid damage to the tendinou portion of the rotator cuff. Eight shoulder specimens were studied. Sharp- and blunt-tipped 4-mm trocars were used to enter the joint. The trapezius was penetrated at all angles of humeral abduction and trocar angulation. The trocar penetrated the tendinous portion of the rotator cuff in all specimens at 90 degrees of abduction, seven of eight specimens at 70 degrees, six of eight specimens at 60 degrees, and three of eight specimens at 45 degrees of abduction. No penetration of the musculotendinous portion occurred when the arm was in 30 degrees of abduction or at the side. When it is necessary to use the supraclavicular portal, traction should be released and the humerus should be brought down to at least 45 degrees. The trocar should be introduced laterally at 30 degrees and angled slightly posteriorly to avoid the tendinous portion of the rotator cuff.     

Glenoid osteolysis after arthroscopic labrum repair with a bioabsorbable suture anchor

Bioabsorbable suture anchors are commonly used for arthroscopic repair of rotator cuff and labrum lesions. They provide soft-tissue attachment to bone. They have been introduced to avoid complications such as artefacts on MRI scans, commonly seen with metal anchors. However, bioabsorbable implants may lead to other problems such as local osteolysis, cyst formation, soft tissue inflammation and release of implant fragments into the joint space. The author describes the case of a professional female volleyball player, who presented osteolysis of the superior pole of the glenoid after arthroscopic repair of a SLAP lesion with a PLLA suture anchor. This is the first reported case of glenoid osteolysis after arthroscopic insertion of a bioabsorbable suture anchor. The author feels that the cause of osteolysis was a biological response to mechanical stress.     

Pullout strength of suture anchors used in rotator cuff repair

BACKGROUND: Surgical treatment of rotator cuff tears may be complicated by osteoporosis of the proximal part of the humerus. The purpose of this study was to determine whether pullout strength of suture anchors is affected by the location of the anchor placement and by bone mineral density. We hypothesized that higher bone mineral density is associated with higher pullout strength of suture anchors. METHODS: Peripheral quantitative computed tomography was used to measure total, trabecular, and cortical bone mineral density in different regions of the lesser and greater tuberosities in seventeen cadaveric humeri. Suture anchors were inserted into individual regions and subjected to cyclic loading. Repeated-measures analysis of variance was used to assess differences in bone mineral density and load to failure between regions of interest. Pearson correlation was used to determine the association between bone mineral density and pullout strength of suture anchors. RESULTS: Total, trabecular, and cortical bone mineral densities were an average of 50%, 50%, and 10% higher, respectively, in the proximal part of the tuberosities compared with the distal part (p < 0.01). Within the proximal part of the greater tuberosity, trabecular bone mineral density of the posterior region and cortical bone mineral density of the middle region were, on the average, 25% and 16% higher, respectively, than the densities in the other regions (p < 0.01). Load to failure in the proximal part of the tuberosities was an average of 53% higher than that in the distal part (p < 0.01). The lesser tuberosity showed, on the average, a 32% higher load to failure than did the greater tuberosity (p < 0.01). Within the proximal part of the greater tuberosity, loads to failure in the anterior and middle regions were, on the average, 62% higher than the load to failure in the posterior region (p < 0.01). Overall positive correlations were found between bone mineral density and load to failure (0.65 相似文献