冻干和辐照对同种异体血管免疫原性的影响

探讨冻干和辐照处理对同种异体血管免疫原性的影响。方法以两个近交系大鼠间同种异体血管移植为模型，比较新鲜和制备血管移植后宿主细胞和体液免疫状态的变化，以及移植血管的病理变化。结果 与新鲜的同种异体血管相比，处理血管移植后不引起宿主的急性排斥反应。     

同种异体肌腱修复肌腱缺损的远期疗效观察

目的总结同种异体肌腱修复肌腱缺损的远期临床疗效。方法 1996年10月-1999年9月,采用经脱氧鸟苷培养冷冻保存与超深低温处理的同种异体肌腱移植修复肌腱缺损24例。男19例,女5例;年龄12～46岁,平均25.9岁。2～5指指总伸肌腱缺损7例,示指伸肌腱缺损7例;2～5指指深屈肌腱缺损3例,环指指深屈肌腱缺损1例;2～5趾趾长伸肌腱缺损3例;长伸肌腱缺损2例;肩胛带离断再植术后肩内收不能1例。肌腱缺损范围5～15 cm。受伤至手术时间为2 h～3个月,平均1.3个月。结果术后切口均Ⅰ期愈合,无深部感染及传染性疾病发生。患者均获随访,随访时间10～12年,平均10.8年。与对侧相同或相近关节比较,术后10年随访时1例4条移植肌腱有6～10°屈曲功能丢失,术后10.6年行屈肌腱松解,术中见同种异体肌腱色泽、弹性正常,直径较原肌腱减少约1/3,有轻度到中度粘连,松解术后功能改善明显;余患者关节伸屈功能良好。根据中华手外科学会手功能评价标准评定临床效果,获优12例,良6例,差6例,优良率达75%。结论脱氧鸟苷培养冷冻处理与超深低温处理的同种异体肌腱均可安全用于临床,其修复肌腱缺损的远期效果较好。     

兔自体骨膜包裹同种异体肌腱移植对腱-骨愈合的影响

目的 探讨兔同种异体肌腱表面包裹自体骨膜植入骨隧道对移植肌腱与骨隧道之间界面愈合的影响. 方法 健康4～5月龄新西兰白兔20只,体重2.5～3.0 kg,随机取一侧后肢作为实验组,另一侧后肢作为对照组.以同种异体肌腱在兔胫骨干骺端建立腱-骨固定模型,实验组骨隧道肌腱表面包裹自体骨膜,骨膜生发层朝向骨隧道;对照组骨隧道肌腱表面不包裹自体骨膜.分别于术后4、8周取标本作腱.骨界面的组织学检查(n=2),并进行最大拔出负荷的生物力学测试(n=8). 结果 术后4、8周标本大体观察,实验组骨隧道口周围新生骨较多;对照组新生骨少或不明显.组织学观察:术后4周实验组骨膜生发层内有大量间充质细胞增生,出现明显的膜内成骨,沿新生骨小梁周围可见大量骨母细胞呈栅形排列,新生骨小梁与骨膜延续:对照组腱-骨界面间无明显新生骨形成,有疏松结缔组织填充,腱-骨间连接较疏松.术后8周实验组新生骨和肌腱与骨隧道连接紧密,无间隙,新生骨量多,新生骨排列比较规则、整齐,腱-骨界面可见潮线形成,类似于正常腱-骨附着结构,骨膜内成纤维细胞增殖活跃,骨膜与肌腱间有较多纤维连接;对照组腱-骨界面局部有新生骨形成,排列紊乱,腱-骨间可见较多胶原纤维连接.术后4、8周,实验组最大拉出或拉断强度分别为(35.03±1.21)N/cm和(42.36±1.31)N/cm,对照组分别为(26.14 ±6.13)N/cm和(31.63±6.87)N/cm,两组比较差异均有统计学意义(P<0.05). 结论 兔自体骨膜包裹同种异体肌腱移植可缩短腱-骨间成骨时间,提高愈合强度,加速腱-骨间愈合.     

同种异体肌腱移植与肌腱库的建立

目的：为临床应用异体肌腱移植提供实验依据以及介绍肌腱库的建立。方法：用经深低温冷冻、冷冻干燥、不加处理的同种异体肌腱和自体肌健移植，修复ＳＤ大鼠跟腱缺损。术后３、８周行免疫原性和生物力学测定、形态学组织学观察。结果：经深低温冷冻与冷冻干燥处理的异体肌腱，有明显降低组织抗原性的作用，并保留了腱组织的生物学特性。结论：深低温冷冻保存的异体肌腱可应用于临床，近期疗效较为满意［１］。     

反复冻融对同种异体人肌腱的生物力学影响

目的分析反复冻融处理对同种异体人肌腱生物力学的影响,为同种异体移植物的处理与保存提供理论依据。方法从3具自愿捐赠新鲜尸体上取30根肌腱(指浅屈肌腱24根、拇长屈肌腱6根),随机分为6组,即新鲜组、冻融1次组、冻融2次组、冻融3次组、冻融5次组和冻融10次组,每组指浅屈肌腱4根,拇长屈肌腱1根。检测各组肌腱结构特性、力学性质及黏弹性变化等生物力学性质并进行比较。结果与新鲜组相比,拉断试验中冻融5次组及冻融10次组最大负荷、最大应力均明显减小,差异均有统计学意义(P<0.05),但最大拉伸及最大应变差异均无统计学意义(P>0.05)。应力松弛试验中,冻融5次组及冻融10次组应力松弛下降速度较快,与新鲜组相比差异均有统计学意义(P<0.05)。蠕变试验出现相似结果,冻融5次组及冻融10次组在100 N拉力作用下更早松弛,产生的蠕变较大,与新鲜组相比差异有统计学意义(P<0.05)。冻融1次、2次、3次组各指标与新鲜组比较差异均无统计学意义(P>0.05)。结论对同种异体移植物经深低温冻存后,冻存-复苏周期不宜超过3个,多周期反复冻融将削弱同种异体肌腱的生物力学性质,使其更容易疲劳、断裂。     

脱氧鸟苷培养处理的同种异体肌腱移植的实验研究

本研究用脱氧鸟苷培养处理鸡趾屈腱，去除其抗原呈递细胞后做活体异体移植．通过混合淋巴细胞培养实验、术趾主动屈曲功能、移植腱腱周粘连定量、羟脯氨酸含量、生物力学测定、血管染色、大体形态及组织学形态观察等证实处理腱免疫源性显著降低，活体异体移植后达到自体腱移植相同良好效果，而对照未处理新鲜异体移植腱被排斥．并发现增生活跃的纤维细胞生成细胶原原纤维（直径３３．３ｎｍ），形成以细胶原原纤维为主并与原粗胶原原纤维（直径３１７．０ｎｍ）并存的新生移植腱．     

同种异体肌腱移植修复手部肌腱缺损及指功能重建的疗效

目的探讨应用同种异体肌腱移植修复手部肌腱缺损及重建屈/伸指功能的临床效果。方法 2015年3月至2017年6月间,我科应用同种异体肌腱移植修复手部肌腱缺损18例22指,男12例,女6例;年龄为20-45岁,平均(32.9±8.3)岁。其中伸肌腱缺损6例8指,屈肌腱缺损12例14指。手部伸肌腱缺损范围6-10cm,平均(7.8±2.1)cm;屈肌腱缺损范围5-8cm,平均(6.6±1.3)cm。患者受伤至手术时间为1.5-8个月,平均(5.0±2.8)个月。术前皮肤软组织缺损者行皮瓣转移修复,骨折及骨缺损者行切开复位或植骨内固定术,手部各指间或掌指关节积极行锻炼至被动活动正常,若关节挛缩则行关节松解术。伸肌腱缝合方法采用编织缝合法,屈肌腱缝合方法采用津下套圈或编织缝合法,屈肌腱滑车缺损者在手术同时重建滑车。术后应用抗生素预防感染,伤口定期换药,所有病例均没有使用免疫抑制剂。术后3d-4周伸肌腱移植者以主动屈曲、被动伸直锻炼为主,屈肌腱移植者以主动伸直、被动屈曲锻炼为主,每天活动3次。4周后逐渐增加活动次数及强度,以主动伸屈活动为主。采用国际手外科联合会制定的手指关节总活动度(total active movement,TAM)评定标准评价手部功能。结果 3例术后出现伤口脂肪液化,细菌培养证实为无菌性渗出,予以伤口定期换药后均于术后20d内愈合;其余病例伤口均一期愈合。3例5指因屈肌腱黏连行肌腱松解术。术后随访8-24个月,平均(14.7±4.8)个月。TAM评价结果,优9指,良7指,可3指,差3指,优良率为72.7%。结论同种异体肌腱移植是代替自体肌建移植修复手部肌腱缺损及重建屈/伸指功能的较好方法之一,具有手部功能恢复满意、临床效果显著等优点,但仍存在术后肌腱黏连导致手功能优良率降低,伤口局部存在无菌性渗出导致愈合时间延长等问题,上述问题需在日后的临床应用过程中加以研究解决。     

VEGF抗体对兔同种异体肌腱移植作用的实验研究

目的 探讨VEGF抗体在异体肌腱移植愈合过程中的作用.方法 将深低温冷冻的同种异体肌腱移植修复新西兰大白兔跟腱缺损,实验组腱周局部滴加VEGF多克隆抗体,对照组滴加生理盐水.术后1、2、4、8周四个时相点处死动物,标本进行大体观察、组织学观察、胶原含量测定及生物力学测试.结果 实验组肌腱粘连等级评分较对照组明显改善,组织学观察可见术后早期实验组较对照组炎性细胞及新生毛细血管数量少,胶原含量差异不明显,但术后8周实验组胶原纤维排列更规则.生物力学测试显示实验组同对照组断裂载荷无显著差异.结论 局部应用VEGF抗体,可以减轻移植肌腱粘连,而对移植肌腱的愈合无明显影响.     

人同种异体肌腱的实验研究及临床应用

[目的]在无水甘油保存液中保存人同种异体肌腱,并做人肌腱移植,评估人同种异体肌腱保存的可行性.[方法]将人同种异体肌腱随机分为2组,即生理盐水组、无水甘油组,各组在12个月进行细菌学检查;将人同种异体肌腱随机分为2组,即新鲜肌腱对照组、无水甘油组肌腱,保存12个月后行生物力学测定;无水甘油组肌腱保存12个月后复水修复人的肌腱缺损.[结果]12个月内无水甘油保存液无细菌生长,保存12个月后进行肌腱的生物力学测试.无水甘油肌腱组:最大拉伸力均值367.2 N,标准差141.6;拉伸刚度107.1 N/mm,标准差31.9.新鲜肌腱组:最大拉伸力均值418.0 N,标准差114.6;拉伸刚度86.0 N/mm,标准差24.6;无水甘油组肌腱修复肌腱缺损22例,28条肌腱,随访7个月～7.8年,平均5.8年,TAM法进行功能测定:优良率72.7％,可13.6％,差13.6％.[结论]无水甘油保存液具有抑制细菌作用,无细菌生长;在无水甘油保存液中常温对肌腱进行保存,在12个月内,无水甘油组肌腱和新鲜肌腱在生物力学上无统计学差异;在无水甘油保存液保存的肌腱可以替代自体肌腱用于肌腱移植,并取得了比较满意的临床效果.     

关节镜下同种异体胫前肌腱与自体腘绳肌腱重建前交叉韧带远期效果的比较

目的:对比同种异体胫前肌腱(tibialis anterior allograft,TAA)与自体腘绳肌腱(hamstring tendon autograft,HTA)重建前交叉韧带(anterior cruciate ligament,ACL)的10年随访临床疗效.方法:回顾分析2007年3月至2010年3月单束重...     

Influence of core suture purchase length on strength of four-strand tendon repairs

PURPOSE: Recently the length of core suture purchase has been identified as a variable affecting the strength of tendon repairs. The influence of the length of the core suture purchase on the strength of multistrand locking and grasping suture repairs, however, has not been studied extensively in transversely lacerated tendons. We assessed the effects of the length of the core suture purchase on the strength of three 4-strand grasping or locking repair techniques. METHODS: Seventy-four fresh adult pig flexor tendons were cut transversely and repaired with 1 of 3 methods: double-modified Kessler, locking cruciate, and modified Savage. Each method was assessed using 2 different lengths of core suture purchase (1.0 and 0.4 cm). The tendons were subjected to a linear noncyclic load-to-failure test in a tensile testing machine. We recorded the forces required for gap formation, ultimate strength, stiffness of the tendon, and the mode of repair failure. RESULTS: The resistance to gap formation, the ultimate strength of all 3 repairs, and the stiffness of the tendons with the double-modified Kessler and modified Savage repairs decreased significantly as the length of core sutures decreased from 1.0 to 0.4 cm. Locking and grasping repairs had a similar decrease in strength when the purchase was decreased from 1.0 to 0.4 cm. All tendons with modified Savage repairs with 1.0-cm purchase failed by suture breakage and tendons with 0.4-cm purchase failed predominantly by pullout. CONCLUSIONS: The length of core suture purchase significantly affects the strength of these 4-strand tendon repairs. The forces required for gap formation and the ultimate failure of repairs with 0.4-cm purchase were 20% to 45% lower than those of the repairs with 1.0-cm purchase. Locking repairs did not show a greater capacity to offset the decrease in strength than grasping repairs when the length of core suture purchase was decreased from 1.0 to 0.4 cm. Our study indicates that the length of suture purchase directly influences the strength of both locking and grasping core tendon repair methods.     

The native tensile strength of the supraspinatus tendon. A biomechanical study

Summary The traumatic tear of the rotator cuff has been discussed very intensively for a long time despite the fact that there do not exist representative objective data about the native tensile strength of these tendons. The aim of this study was to evaluate the age related native strength of the supraspinatus tendon. 25 fresh frozen cadaver specimen (age: 23–94, 24 h post mortem, 18 male, 7 female) were tested using so called cryo-jaws for soft tissue fixation. The results showed the major part of the tensile forces to be transmitted through the anterior thicker part of the tendon (e. g. 14 bony avulsions in this area). We found significant correlations between age and maximum strength (p < 0.001), age and stiffness of the tendon (p < 0.005) and stiffness and maximum strength (p < 0.001). These results show that tensile strength and stiffness of the supraspinatus tendon decrease with age. However, a 65 year old specimen still demonstrates a weight bearing structure (about 900 N maximum tensile strength) and is not necessarily ruptured or degeneratively altered.      

The tensile strength of various peripheral circumferential repair techniques in canine flexor tendons

The purpose of this study was to evaluate the tensile strength of six peripheral circumferential suture techniques, using a variable number of suture strands. Transverse lacerations were made in 184 fresh frozen canine flexor profundus tendons and repaired using only a 6-0 Prolene circumferential suture. The six running suture techniques were: Simple, Simple-locking, Lembert, Halsted, Cross-stitch and Lin-locking, and 6, 10, 14, and 20 suture strands were used. For each technique, the tensile strength gradually increased with the increased number of suture strands. The tensile strength of the Lin-locking technique (19–34 N) was greater than that of the other techniques, followed by Cross-stitch (16–33 N), Halsted (10–25 N), Lembert (8–23 N), Simple (6–12 N), and Simple-locking (5–8 N). The Lin-locking had the best holding power, but it was technically the most complicated to place. The Cross-stitch had good tensile strength values. The Simple and the Simple-locking had the lowest tensile strengths. From the viewpoints of tensile strength and technical skill, the Cross-stitch may be preferable to other suture techniques.     

Tendon allograft for treatment of chronic Achilles tendon rupture: A systematic review

BackgroundTo summarize available evidence and determine if tendon allograft is an effective treatment for chronic Achilles tendon rupture.MethodsA search was performed in the PubMed, Web of Science, Embase and Cochrane Database from 1960 to April 2017 to identify relevant articles. Predefined inclusion and exclusion criteria were applied to identify all eligible articles.ResultsTotal 186 articles were identified through our systematic search. Of these, 9 publications met the inclusion criteria. Five studies were case reports; three were case series; and one were expert opinion. Of a total 35 patients, 34 underwent Achilles tendon allograft repair and 1 peroneus brevis tendon allograft reconstruction. All patients experienced good clinical and functional results, but most reports used non-validated outcome measures.ConclusionsThe evidence suggests that tendon allograft offers favorable outcomes in patients with chronic Achilles tendon rupture. However, randomized controlled trials which use validated functional outcome measures are required to determine effectiveness of this intervention.Level of evidence: Level V, systematic review of Level IV and V studies.     

The effects of freezing on the tensile properties of repaired porcine flexor tendon

PURPOSE: When conducting complex testing of tendon repairs, it is essential that the samples are adequately preserved to prevent degradation. Freezing of samples is the most convenient method of preservation; however, there is no evidence in the literature to prove that freezing tendon before or after repair is acceptable. We aimed to prove that freezing tendons does not significantly alter the results of linear load-to-failure testing of tendon repairs. METHODS: After a power study, 150 tendons were harvested from porcine forelimbs and randomized into 5 groups of 30 tendons. After division, tendons were repaired using a Pennington modified core technique with a Silfverski?ld peripheral cross-stitch. Tendons in group 1 were divided, repaired, and tested within 3 hours postmortem. Tendons in group 2 were refrigerated at 4 degrees C for 24 hours prior to repair and testing. Tendons in group 3 were frozen at -25 degrees C for 3 months prior to repair and testing. Tendons in group 4 were frozen at -25 degrees C for 6 months prior to repair and testing. Tendons in group 5 were frozen at -25 degrees C for 6 months, repaired, refrozen for 1 month, and then tested. All repairs were linear load tested to ascertain the ultimate strength and force to produce 3-mm gap in the repair. RESULTS: Analysis of variance analysis of the results did not demonstrate any significant differences between groups. CONCLUSIONS: Freezing tendons both before and after suture repair is an acceptable method of preservation when investigating the force to produce 3-mm gap and ultimate strength of tendon repairs.     

Effect of circumferential sutures on tensile and gap strength of repaired canine flexor tendons

Sixty-four dog cadaver flexor digitorum profundus tendons in zone 2 were lacerated and repaired with a simple or a cross-stitch peripheral circumferential suture in combination with two-, four-, or six-strand core sutures. The tensile and gap strengths were compared. The range of tensile strengths with the cross-stitch circumferential suture in combination with various core suture techniques (4.28–9.37 kgf) was significantly higher than the range of values for the simple circumferential suture and similar core suture techniques (1.70–4.98kgf). The tensile strength with two-strand core suture plus the cross-stitch circumferential suture (5.29kgf) was as great as that of the six-strand core suture plus the simple circumferential suture (4.98kgf). Increased gap strength values were also observed with the cross-stitch (1.11–3.19 kgf) compared to the simple (0.84 to 1.76 kgf) circumferential sutures. The cross-stitch circumferential suture had a mechanical advantage in flexor tendon repair compared to the simple circumferential suture. No benefits in any form have been received or will be received from any commercial party related directly or indirectly to the subject of this article. This study was supported in part by Grant No. 15953 from the Shriner's hospital for Crippled Children (USA)     

Comparative biomechanic performances of locked cruciate four-strand flexor tendon repairs in an ex vivo porcine model

PURPOSE: To investigate the effects of 3 different locking configurations on repair strength when used in a cruciate four-strand repair. METHODS: Sixty fresh porcine flexor tendons were transected and repaired with cruciate four-strand core suture repairs with 3 different locking configurations: simple locks (a modification of the Pennigton method), circle locks, and cross locks. Half of the repairs in each locking group were reinforced with a peripheral suture. The tendon repairs were subjected to linear load-to-failure testing. Outcome measures were 2-mm gap force and ultimate tensile strength. RESULTS: The cross lock repair had significantly greater 2-mm gap force and ultimate tensile strength than the simple lock repair, both with and without a peripheral suture. The cross lock repair showed significantly greater 2-mm gap force without a peripheral suture and significantly greater ultimate tensile strength with a peripheral suture than the circle lock repair. With peripheral reinforcement, the cross lock cruciate repair had a mean 2-mm gap force of 92 N and ultimate tensile strength of 119 N. The cross lock cruciate repair consistently produced the strongest biomechanic performance in all outcome measures. CONCLUSIONS: Locking configuration influences the biomechanic performance of cruciate four-strand flexor tendon repairs. Our results suggest that the cruciate repair with cross locks is stronger than repairs with simple locks or circle locks. Whether the results of this ex vivo porcine linear model can be translated to the clinical arena is unknown, because the factors of tendon/sheath friction, tendon healing, and compromised tendon viability from the lock were not addressed.     

玻璃化法保存异体肌腱移植的组织学研究

[目的]对玻璃化法与程序冷冻法保存异体肌腱移植后的组织学演变及特性进行观察、分析,以了解其临床应用的可行性及影响因素.[方法]家兔36只,平均分为A组为新鲜自体肌腱移植组,B组为玻璃化法保存异体肌腱移植组,C组为程序冷冻法保存异体肌腱移植组,对术前、术后3、8、12周异体肌腱的形态学、组织学演变进行观察.[结果]玻璃化法保存肌腱完整率高于程序冷冻法,差异有显著性.A、B组移植后较C组粘连轻,光泽好.新生血管、腱细胞成熟早,愈合进程快.[结论]玻璃化法较好地保存了肌腱的细胞外结构,玻璃化法保存异体肌腱移植具有接近正常肌腱的组织学特性,其效果优于程序冷冻法.