异体半月板移植的研究进展

膝关节半月板具有重要的生物力学功能，它可增加关节软骨之间的接触面积，降低关节软骨单位面积上的负荷；它的楔形截面可稳定膝关节，其弹性组织结构可吸收振荡；此外，半月板对关节软骨还具有润滑作用。半月板切除后，将丧失上述功能，导致或加速膝关节的退行性变。因此，近１０年来开始采用异体半月板移植技术重建受损半月板，缓解临床症状和阻止因半月板丧失导致的膝关节退行性变的发展。一、异体半月板移植的动物实验Arnoczky等犤１犦报告１４例成年犬低温保存的异体内侧半月板移植，观察２周～６个月，移植半月板的外形保持正常，与…     

兔同种异体半月板移植后膝胫股关节面生物力学重建的研究

目的探讨兔同种异体半月板移植后膝关节内侧间隙受力面积、压强的变化及其生物力学重建情况。方法 6～7月龄清洁级日本大耳白兔28只,雌雄不限,体重3.0～3.5kg;随机取7只兔右膝关节内侧半月板,制备同种异体半月板。余21只兔随机分为3组,每组7只。A组为空白对照组,单纯打开膝关节后缝合;B组为右膝内侧半月板切除组;C组为右膝内侧半月板切除后行同种异体半月板移植组。术后观察各组实验动物一般情况,于12周处死实验动物取右膝关节行生物力学测试,并取A、C组半月板行组织学及免疫组织化学染色观察。结果术后实验动物均存活至实验完成。术后12周大体观察见C组移植半月板愈合较好,前后角及体部附着良好。术后12周膝关节屈膝0、30、60、90°时,B组膝关节内侧间隙受力面积及压强与A、C组比较,差异均有统计学意义(P<0.05),A、C组间比较差异均无统计学意义(P>0.05);屈膝120°时,任意两组间受力面积及压强比较,差异均有统计学意义(P<0.05)。组织学观察显示C组软骨细胞及胶原纤维数量恢复正常;免疫组织化学染色示C组移植半月板内胶原纤维含有大量Ⅰ型胶原和Ⅱ型胶原。术后12周A、C组Ⅰ型胶原含量分别为0.6125±0.0598和0.5872±0.0639,差异无统计学意义(t=0.765,P=0.465);Ⅱ型胶原含量分别为0.7724±0.0815和0.8143±0.0517,差异无统计学意义(t=—0.136,P=0.894)。结论兔同种异体半月板移植可增加膝关节受力面积,减小压强,有利于保护关节软骨,并可重建生物力学平衡。     

改善异体半月板移植预后的相关因素研究

异体半月板移植的目的是恢复半月板缺失膝关节的正常生物力学环境,保护关节软骨,延缓膝关节退变性关节炎的发生。异体半月板的构成、大小匹配程度、移植物再血管化的速度以及是否应用相关的生长因子等,影响移植预后。     

同种异体半月板移植术临床效果的初步分析

目的探讨关节镜下异体半月板移植的手术适应证、康复训练计划和免疫反应等问题。方法建立国人异体半月板组织库，对12例半月板损伤后切除半月板的患者，在关节镜下实施异体半月板移植微创手术，制定康复计划，观查其临床效果，结合文献讨论异体半月板移植术的围手术期相关问题。结果本组患者均无手术副损伤，早期关节轻度肿胀，无伤口渗液。术后2周，伤口愈合良好。术后6周，关节肿胀基本消失。随访6—17个月（平均10．3个月），患者行走功能正常，膝关节活动度均值与术前比较差异无统计学意义。膝关节疼痛评分（VAS）术后明显低于术前（P〈0．01）。Lysholm评分术后明显提高（P〈0．05）。术后各项免疫学指标均在正常范围。MRI示移植半月板位置良好，固定可靠。1例患者术后12周关节镜检查，见移植半月板形态正常，与关节囊愈合良好。结论鉴于目前对半月板切除术后（半月板缺损）的并发症治疗存在很大困难，异体半月板移植可能成为一项重要的临床治疗技术。异体半月板移植可获得较好的近期临床效果，临床未见明显的免疫排斥反应。但有关异体半月板移植手术适应证、康复训练及远期效果等围手术期的相关问题还需更深入的探讨。     

骨髓基质细胞移植修复半月板无血运区损伤的实验研究

目的比较自体与同种异体骨髓基质细胞移植对半月板无血运区损伤修复的影响。方法 40只成年新西兰大白兔随机平均分为 A、 B两组。 A组兔的骨髓基质细胞 (MSC)经体外培养后与纤维蛋白凝胶 (FG)混合,自体移植于其一侧的膝关节半月板缺损区,即 FG＋自体 MSC（自体移植组）;另一侧单纯植入 FG(FG植入组 )。于 B组兔的一侧膝关节半月板缺损区移植 FG＋同种异体 MSC(异体移植组 ),另一侧缺损不予修复 (空白对照组 )。分别于术后第 1、 2、 3个月取材,观察半月板损伤部位的组织形态学变化。结果 (1)自体移植组 :术后 1个月缺损区可见纤维组织,内有大量成纤维细胞;术后 2个月见大量软骨细胞并有胶原纤维形成;术后 3个月损伤区呈纤维软骨愈合。 (2)空白对照组 :术后 1～ 3个月缺损区始终未愈合。 (3)单纯 FG植入组 :术后 1～ 3个月缺损区可见纤维组织,内有少量成纤维细胞,没有软骨细胞生长,呈瘢痕样愈合。 (4)同种异体移植组 :与自体移植组所见大致相同,但有 3侧缺损区可见大量淋巴细胞浸润,胶原纤维少。结论骨髓基质细胞移植可促进半月板无血运区损伤的愈合,同种异体骨髓基质细胞移植修复半月板无血运区损伤发生免疫排斥反应的机率较低。     

异种半月板移植实验研究的初步报告

目的观察生物型异种半月板移植修复羊半月板缺失的效果,探讨生物型半月板重建正常膝关节半月板的可行性。方法以猪膝关节内侧半月板为供体,应用环氧固定技术对猪半月板进行去抗原处理,制成生物型异种半月板移植体。随机切除6只山羊一侧膝关节内侧半月板,将生物型异种半月板塑形并与羊内侧半月板的形态和尺寸相匹配,原位植入半月板缺失部位。分别于术后12周、24周、36周处死动物,对移植半月板、股骨内侧髁及内侧胫骨平台进行大体形态、病理切片和电镜扫描观察。结果随着时间延长,异种移植半月板与周边组织愈合良好,并逐渐被新生组织替代;术后12周,移植膝关节软骨未见退变,24～36周后移植膝关节软骨出现轻度退变,移植半月板出现被吸收和宿主纤维母细胞爬行替代现象。结论我们初步认定,生物型异种半月板作为羊半月板缺失移植的供体可被宿主细胞逐渐替代,逐步形成新生的自体半月板,且短期内对移植膝关节软骨具有明显的保护作用;在实验各阶段均未出现明确的免疫排斥反应。     

自体肋软骨膜游离移植修复下颌髁状突软骨的组织学研究

为了观察自体肋软骨膜游离移植再生关节软骨的组织学改变，用５０只中国本兔进行了实验。通过组织学、电镜和放射自显影方法，对自体肋软骨膜游离移植于下颌髁状突切骨面后再生软骨的生长发育过程进行了观察。发现：术后１０天移植的软骨膜增厚，间充质样细胞增生。至术后３０天，软骨细胞逐渐发育成熟。６０天后，新生的软骨关节面光滑，细胞形态和排列趋于规则，与正常关节软骨形态相似。结果表明，自体肋软骨膜游离移植于髁状突骨面可以形成新的软骨关节面，其组织学形态与正常关节软骨相同；新生软骨生长发育过程与正常软骨相同；关节运动和负重能促进新生软骨形成并进行生物性改建，逐渐形成正常的关节形态。为临床应用软骨膜移植修复髁状突软骨损伤提供了依据。     

冷冻保存同种异体骨-前交叉韧带(ACL)-骨移植实验研究

目的探讨自体骨-ACL-骨和二步冷冻保存同种异体骨-ACL-骨移植的组织学、形态学及生物力学的变化特点。方法将60只日本大耳兔和60只新西兰兔随机分成自体骨-ACL-骨移植组和二步冷冻保存骨-ACL-骨同种异体移植组。术中及术后不用免疫抑制剂。术后4、8、12周切取移植膝关节及健侧膝关节,行ACL生物力学测试。术后4、12周切取ACL分别作组织学检查和电镜检查。结果自体移植组和二步冷冻保存同种异体骨-ACL-骨移植组的ACL所测最大拉伸强度和拉伸刚度与同期正常对照ACL相比显著下降(P<0.01)两组之间同期相比其最大拉伸强度和拉伸刚度差异无显著(P>0.05)。结论自体骨-ACL-骨移植和二步冷冻保存同种异体骨-ACL-骨移植后具有相同的生物力学性能和组织学愈合过程。     

自体游离骨膜再造膝关节半月板的实验研究

目的：对于严重损伤的半月板全切除术后行自体游离骨膜重建半月板，以维持膝关节结构、生理及功能特性。方法：使用１７只成年犬，５只幼犬。外侧半月板全切除以后，胫骨内侧近端的骨膜游离并移植到外侧半月板部位。于２、４、８、１２、２４、４８周取下重建半月板及不同部位的关节面软骨进行大体、光镜及电镜观察。结果：术后２个月，重建半月板的大体形态、组织结构与正常半月板近似。外侧股骨软骨面及没有被覆盖的胫骨软骨面表现退行性改变，被移植物覆盖的软骨面退变较轻。幼犬的退变更早、更严重。结论：本研究说明了自体游离骨膜在滑液环境及受到合适的应力刺激会向纤维软骨演化，在半月板全切除后，应用游离骨膜重建半月板是可行的     

关节软骨和半月板组织碎块移植研究进展

关节软骨和半月板无血运区损伤后不能自然愈合,软骨组织碎块移植为之修复提供了新思路。体外和体内实验研究均证实,关节软骨及半月板无血运区切成碎块后细胞能有效地从碎块组织释放,与周围支架材料复合或直接导致组织修复。自体软骨植入系统（CAIS）及同种畀体幼年关节软骨碎块移植物（DeNovoNT）,已应用于,临床。该文就关节软骨及半月板组织碎块移植的基础研究及临床应用研究及其进展作一综述。     

Free synovium promotes meniscal healing: Synovium, muscle and synthetic mesh compared in dogs

We studied the effect of free synovium on the healing of tears in the avascular portion of the menisci in dogs. A longitudinal incision was made in the medial meniscus. In 35 dogs, a free graft of synovium was inserted into the tear and sutured. In 10 dogs, a free graft of quadriceps muscle was used. In 10 dogs, a Dacron mesh was inserted. In the contralateral knee, the tear was sutured without implantation as a control. 2, 4, 6, 8, and 12 weeks after the operation, the menisci were dissected. 11 of the 35 with free synovium were healed. The menisci with muscle grafts, those with Dacron mesh and those in the control group did not heal. Histology showed that tears were repaired with fibrous tissue. Microangiography showed that capillaries grew from the periphery, but they did not reach the tear.     

Meniscal replacement using a cryopreserved allograft. An experimental study in the dog

The medial menisci of 14 adult dogs were replaced using a cryopreserved meniscal allograft. The morphology and metabolic activity of the transplanted allografts were then evaluated using routine histology, a vascular-injection (Spalteholz) technique, and autoroentgenography (Na2(35)SO4 incorporation) at various intervals, from two weeks to six months postoperatively. After transplantation, the allografts retained their normal gross appearance and healed to the capsular tissues of the host by fibrovascular scar tissue. Histologically, the grafts demonstrated a decrease in the number of metabolically active cells after transplantation but had a normal cellular distribution and Na2(35)SO4 uptake by three months. The allografts appeared to function normally after transplantation. Although some degenerative changes were noted in the tibial articular cartilage not covered by the meniscus, the cartilage beneath the allograft appeared normal.     

Autologous meniscus replacement with rib perichondrium. Experimental results

The purpose of our study was to examine the potential of autologous perichondrial tissue to form meniscal replacements. Eighteen mature sheep were used. In 12 animals a complete meniscal resection was performed; replacement was formed using strips of autologous perichondrial tissue explanted from the lower rib; six animals with a complete meniscal resection but without any replacement served as controls. In all animals restriction from weight-bearing was achieved by means of transsection and partial achillestendon resection. Six animals each, 4 of group T and 2 of group C, were sacrificed after 3, 6 and 12 months. Perichondrial grafts and the underlying articular cartilage were removed and investigated by gross macroscopic examination, by means of light and scanning electron microscopy, polarized light examination, and biomechanical tests evaluating the failure stress and tensile modulus. In all transplanted animals a new perichondrial meniscus developed. After 3 months the transplants resembled in size and thickness normal menisci, while in the control animals only small rims of spontaneously grown tissue were detectable. Microscopically, the perichondrial menisci exhibited similarity to normal collagen fiber orientation and cellular characteristics, but, in their central region, areas of calcification disturbed the regular tissue differentiation. In contrast, spontaneously grown tissue in control animals lacked normal fiber orientation and cellularity. Scanning electron-microscopy of perichondrial menisci revealed surface characteristics similar to normal sheep menisci without fissures and lacerations, while the control specimens exhibited such defects. The femoral and tibial cartilage being in contact with the new menisci showed normal surface characteristics apart from one animal with slight surface irregularities. Control animals showed superficial lesions after 3 months, and the extent increased from 6 to 12 months postoperatively. Exemplary microangiographies of the newly grown tissue exhibited a less intense vascularisation after three months when compared to normal menisci with an improving tendency after 6 and 12 months. Biomechanically, values of the failure stress as well as of the tensile modulus of perichondrial menisci were significantly lower than those of normal contralateral menisci. But, spontaneously regenerated tissue in meniscectomized animals exhibited even smaller values also with significant differences towards original menisci. There were no significant differences in values of newly grown perichondrial menisci and spontaneously grown tissue.     

Structural analysis of meniscal allografts after immediate and delayed transplantation in rabbits

Purpose: To compare long-term performance of meniscal allografts transplanted immediately after meniscectomy and allografts transplanted 6 weeks after meniscectomy. Type of Study: Experimental study. Methods: Twenty-one rabbits were subjected to meniscectomy and divided into 3 groups of 7 animals. Immediate meniscal transplantation was performed in group A (6-week follow-up) and group B (1-year follow-up). Group C underwent delayed transplantation 6 weeks after meniscectomy. One animal in group B developed infective arthritis and was not included. Six nonoperated knees served as controls. Four other knees were subjected to a sham procedure. Menisci were examined macroscopically and histologically at 6 weeks (group A and 2 sham- operated animals) and 1 year (group B, C, controls, and 2 sham-operated animals). Results: Capsular ingrowth was observed in all allografts. At 1 year, osteoarthritic changes in the delayed transplant group were more pronounced than in the immediate transplant group. Menisci in nonoperated controls and sham-operated knees appeared normal. No differences in shrinkage of allografts were observed between groups A and B. Group C showed significantly more shrinkage than allografts in both group A (P = .004) and group B (P = .005). Two allografts in group C were completely degenerated. Differences in architecture of the allografts were not found between groups A, B, and C. In both the peripheral and central areas of transplanted menisci, the number of cells was frequently increased because of repopulation even at 6-week follow-up. Conclusions: Delayed meniscal allograft transplantation causes distinct structural damage to menisci in comparison with immediate transplantation.     

Vascularized synovial flap promoting regeneration of the cryopreserved meniscal allograft: experimental study in rabbits

 The purpose of this investigation was to evaluate whether a vascularized or free synovial flap or a fibrin clot can promote regeneration of meniscal allograft in the rabbit. Seventy-eight mature New Zealand white rabbits were used. The harvested medial meniscus for the allotransplantation was frozen and stored at −80°C for 2 weeks. After resecting the medial meniscus, an allogenic meniscus was transplanted in the anatomical position (group A). The surface of the graft was covered by a vascularized synovial flap (group B), a free synovial flap (group C), or a fibrin clot (group D). The animals were killed 4, 6, 8, 12, and 16 weeks after transplantation, and the transplants were examined by gross inspection, histology, and microangiography. Connective tissue infiltration into the matrix of the graft was found to begin at 6 weeks (2/5 menisci) and to be complete at 8 weeks (5/5 menisci) in group B, whereas it began at 8 weeks (1/5) in group A. The newly formed repair tissue developed from the synovial tissue and consisted of connective tissue at the beginning and fibrocartilage later. The fibrocartilage had appeared at 8 weeks (3/5) in group B but not yet in group A (0/5). A free flap or fibrin clot coverage resulted in delayed revascularization compared to a vascularized synovial flap, but both tended to achieve faster revascularization than the controls. We concluded that regeneration of allografted meniscus with a vascularized synovial flap occurs earlier than under other conditions. Thus, allografts with synovial implantation may be considered for management of the meniscectomized knee. Received: October 18, 2001 / Accepted: September 27, 2002 Offprint requests to: K. Yamazaki     

Free synovium grafting for the repair of the avascular portion of canine knee joint meniscus]

To evaluate the effect of free synovium on repair of avascular portion of the meniscus in the knee, two round full-thickness defects of 2 mm phi were made in the medial menisci of 57 dogs, followed by transplantation of free synovium or blood clots in the holes. Defects with no grafting served as control. Specimens were evaluated histologically at intervals from 1 day to 12 weeks after grafting. The portions of the medial menisci filled with blood clots gradually retracted after surgery and showed no complete repair 6 and 12 weeks after the operation as in the control. In the group which received synovial graft, however, fibrous reparation was observed in 62% of total 13 defects 3 weeks after grafting. Six and 12 weeks after the synovial transplantation, complete reparation by fibrocartilaginous tissue with no signs of tissue retraction was observed in more than 65% of total 17 defects. Therefore, synovial grafting seemed to be a potential method for the repair of the avascular portion of the canine knee joint meniscus.     

Exogenous transforming growth factor beta 1 alone does not improve early healing of medial collateral ligament in rabbits.

OBJECTIVE: To determine whether transforming growth factor beta 1 (TGF-beta1) improves early ligament healing. DESIGN: Experimental, controlled study of medial collateral ligaments (MCLs) in rabbits' knees. SETTING: Research laboratory. SUBJECTS: Sixteen skeletally mature, New Zealand White female rabbits. INTERVENTIONS: Ten rabbits had a standardized gap injury made in the MCL of both knees. Three weeks later, a second operation was performed to inject 7 microg of TGF-beta1 in a carrier solution into the right knee MCL, while the left knee MCL was injected with carrier alone. The rabbits were killed 3 weeks after the injection of TGF-beta1 (6 weeks after the original injury). Six of the rabbits (12 knees) had no operation on the MCL and served as external normal controls. OUTCOME MEASURES: Biomechanical measures of the femur-MCL-tibia complex. Histologic evaluation of MCL cell and matrix organization. Transmission electron microscopy measures of MCL fibril diameters. RESULTS: There were no statistically significant differences in the biomechanical measures, fibril diameter distributions and histologic evaluation of the injured MCLs treated with TGF-beta1 or carrier alone. Both groups of injured MCLs were significantly different from normal MCLs. CONCLUSIONS: The results indicate that the dosage and route of delivery of TGF-beta1 did not lead to overt improvement in the healing of the injured MCL. Whether different doses or delivery methods, alone or in combination with TGF-beta1, or other growth factors would lead to improvement remains to be determined.     

Transplantation of cryopreserved canine venous allografts

Local vascular reconstructions frequently require the use of vein grafts to bridge arterial or venous defects. Most previous studies on the use of cryopreserved veins have used relatively large caliber vessels. There have been few studies on the effectiveness of cryopreserved micro- or small-venous allografts. Here, we tested two types of cryopreserved venous allografts: (1) 1.5- to 1.9-mm diameter microvenous grafts (MVG); and (2) 4- to 5-mm diameter small venous grafts (SVG). Cryopreserved MVG allografts were placed into saphenous arteries of six experimental dogs and SVG cryopreserved allografts were placed into femoral arteries of six experimental dogs for 3 to 6 weeks. Two fresh MVG autografts were also transplanted into experimental dogs as controls and autografts were transferred to the contralateral side in SVG dogs as controls. None of the six cryopreserved MVG grafts retained patency but three/six cryopreserved SVG allografts were patent at harvest. Histological examination of grfts revealed control autografts were undergoing arterialization with an intact intima. Experimental cryopreserved allografts showed extensive medial fibrosis, significant lymphocytic infiltrates, and sporadic areas of intact intima for both patent and nonpatent grafts.