Effect of hylan G-F 20 in Achilles' tendonitis: an experimental study in rats

OBJECTIVE: To investigate the local effects of hylan G-F 20 on locally administered corticosteroid-induced experimental Achilles' tendonitis. DESIGN: Before-after trial. SETTING: Institutional practice. ANIMALS: Convenience sample of 18 male Wistar white rats (weight range, 322-375 g). INTERVENTIONS: After performing Achilles' degeneration with local corticosteroid injections, the rats were divided into 4 groups. The right Achilles' tendon of the rats served as the hylan injection group and the left tendon as the control group, which was injected with saline at 5-day intervals. The tendons and paratenons were excised at the end of 60 or 75 days and evaluated histopathologically and statistically. MAIN OUTCOME MEASURE: Histopathologic changes, including staining affinity, nuclear appearance, fibrillar appearance for tendon and thickness, occurrence of fibrosis and edema, capillary changes, and inflammation for paratenon, were assessed according to a semiquantitative scoring system. The Mann-Whitney U test was used for statistical analysis, with a P value of.05 or less considered statistically significant. RESULTS: Semiquantitative scoring of histopathologic changes showed that histologic appearances differed between the hylan and saline groups and between 2 hylan groups. Hylan-injected tendons and paratenons demonstrated significantly lower scores, especially after 75 days. CONCLUSIONS: Hylan G-F 20 has a promising curative effect on the tendon and paratenon and can be used in Achilles' tendonitis. This finding should be supported by biomechanical and biochemical studies.     

Recombinant fibroblast growth protein enhances healing ability of experimentally induced tendon injury in vivo

This study was designed to investigate the effects of recombinant human basic fibroblast growth factor (bFGF) on a complete superficial digital flexor tendon (SDFT) rupture after surgical repair in rabbits. Eighty mature New Zealand White rabbits of both sexes were randomly divided into two equal groups: Treated and Control. Each group was subdivided into two 28‐ and 84‐day post‐injury subgroups. After tenotomy and surgical repair, the animals were immobilized for 14 days. In the treated group, bFGF was directly applied subcutaneously over the lesion on days 3, 7 and 10 after injury. The control animals received normal saline injection of the same viscosity and volume and at the same intervals. Ultrasonographical observations were conducted at weekly intervals. The animals were euthanized at 28 and 84 days after injury. The tendons were evaluated at macroscopic, histopathologic and ultrastructural levels and were assessed for biomechanical and percentage dry weight parameters. Compared to injured control animals, treated animals showed a decrease in the diameter of the injured tendon and peritendinous adhesion as well as increased tenoblast proliferation, collagen production and ultimate strength of the injured tendons (p < 0.005). At 84 days after injury, treatment resulted in enhanced maturation of the cellular and collagen elements and improved tissue alignment and density. These improvements resulted in increased biomechanical performance of the injured tendons compared to controls (p = 0.001). bFGF showed promising curative effects on restoration of the biomechanical and morphological properties of the ruptured SDFT in rabbits and may be applicable in clinical studies. Copyright © 2012 John Wiley & Sons, Ltd.     

Static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon

BACKGROUND: Since tendons show viscoelastic behavior, dynamic viscoelastic properties should be assessed in addition to static biomechanical properties. We evaluated differences between static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon following tenotomy. METHODS: At 3, 6, or 12 weeks after right Achilles tenotomy, the right (regenerating) and left (control) tendons were collected with the calcaneus from 49 rabbits. A unidirectional failure test and a dynamic viscoelastic test were conducted. FINDINGS: Tensile strength and Young's modulus (static biomechanical properties) in the regenerating group at Week 6 were significantly greater than at Week 3, while at Week 12, these were significantly greater than at Week 6. However, even at Week 12, both parameters were less than in the control group. The value of tan delta represents dynamic viscoelasticity, a smaller tan delta indicates greater elasticity. tan delta for the regenerating group was significantly greater than for the control group at Week 3, but regenerating and control groups did not significantly differ at Week 6. No marked change was seen from Weeks 6 to 12 in the regenerating group, and no significant difference in tan delta was evident between the regenerating and control groups at Week 12. INTERPRETATION: Dynamic biomechanical properties of regenerating rabbit Achilles tendons may improve more rapidly than static biomechanical properties. Ability to tolerate dynamic movement in the healing Achilles tendon may improve more rapidly than ability to withstand static stresses.     

Quantitative histology and ultrastructure fail to explain weakness of immobilized rabbit Achilles' tendons

OBJECTIVE: To test the hypothesis that mechanical weakness caused by immobilization is the result of characteristic histologic and ultrastructural changes in rabbit Achilles' tendons. DESIGN: Single-blind, randomized controlled trial. SETTING: University animal care facility. ANIMALS: Twenty-three New Zealand rabbits. INTERVENTION: Twenty weight-matched rabbits underwent unilateral hind leg immobilization. The Achilles' tendons of immobilized and contralateral legs were harvested after 4 or 8 weeks. For ultrastructural outcomes, 6 normal Achilles' tendons of 3 rabbits served as controls. MAIN OUTCOME MEASURES: Light microscopic assessments were made on the tendons for cross-sectional area of the tendon, number of tenocytes, adipocytes and blood vessels, roundness of nuclei, area of intense metachromasia, and area of spatially aligned collagen fibers. Transmission electron microscopy (TEM) measured mean collagen fibril diameter and density. RESULTS: Light microscopic assessment failed to reveal a statistical difference in any of the outcome measures between immobilized and contralateral tendons. TEM did not show a statistical difference in mean fibril diameter between the immobilized groups (4 wk, 113.8+/-1.6 nm; 8 wk, 113.5+/-1.4 nm) compared with their respective contralateral tendons (4 wk, 111.4+/-1.4 nm; 8 wk, 116.2+/-1.8 nm) and normal controls (111.8+/-2.0 nm). Eight-week contralateral fibrils were statistically larger than 4-week contralateral fibrils, which was attributed to a training effect of the leg opposite of the casted leg. CONCLUSIONS: Our results add to the recent literature about the absence of characteristic histologic or collagen fibril size markers that could explain the mechanical weakness of immobilized tendons. Further research using biochemical, gene expression, and functional imaging markers of tendon is needed to pinpoint the alterations responsible for the mechanical weakness. Such markers would be crucial for the rehabilitation and secondary prevention of tendon injuries.     

甘油常温保存肌腱的两种方法比较

背景:最大程度保留肌腱的生物活性是进行同种异体肌腱移植的条件。目的:通过比较选择出最佳的肌腱常温保存方法。方法:使用无菌操作的方法将兔肌腱随机分为4组:新鲜肌腱对照组、生理盐水组、无水甘油Ⅰ组(肌腱梯度脱水后在无水甘油中保存)、无水甘油Ⅱ组(肌腱直接在无水甘油中保存),分别于保存的第2,4,7个月进行检测。结果与结论:苏木精-伊红染色显示:无水甘油Ⅰ组肌腱细胞完整率明显高于无水甘油Ⅱ组。电镜观察发现,无水甘油Ⅰ组大部分肌腱细胞形态正常,肌腱组织结构完整;无水甘油Ⅱ组保存4,7个月后细胞核凝固、固缩、崩解状。无水甘油Ⅰ组的超氧化物歧化酶活性也明显高于无水甘油Ⅱ组。说明肌腱经梯度脱水后在无水甘油中常温保存效果更佳。     

无水甘油保存同种异体肌腱的移植

背景:如何处理和保存同种异体肌腱,使之尽可能保留生物活性并降低其免疫原性是近年研究热点。目的:将保存于无水甘油的兔肌腱进行同种异体移植,观察移植后肌腱的组织学变化。方法:将兔肌腱经特殊处理后,常温避光保存在无水甘油中,保存7,12个月后取出肌腱,移植到兔后腿屈肌腱中。饲养3个月后处死并取出移植的肌腱,进行苏木精-伊红染色石蜡切片及透射电镜观察。结果与结论:苏木精-伊红石蜡切片示肌腱纤维排列尚整齐,细胞形态正常,切片某些区域细胞密度较正常组低,未见明显的炎性细胞浸润。透射电镜示肌腱纤维排列整齐,细胞形态正常。结果提示经无水甘油保存的肌腱进行同种异体移植后,在组织学上与正常肌腱相似,无明显的免疫排斥反应。     

超声对脊柱关节病患者多系统风湿性炎性病变的疗效评价

目的　探讨超声在脊柱关节病( spondyloarthropathy,Sp A)患者疗效评价中的价值。方法　对比8例有膝关节炎或跟腱肌腱端炎的Sp A患者病变部位局部治疗前后的高频声像和血流情况,并与治疗前后的血沉、C反应蛋白和毕氏强直性脊柱炎活动指数作对比分析。结果　治疗前后比较,两组患者血沉、C反应蛋白差异均无显著性( P>0 .0 5 ) ,而膝关节治疗组患者的髌上囊滑膜厚度、积液厚度和滑膜血流等级及跟腱治疗组患者的跟腱止点血流等级差异均有显著性( P<0 .0 5 )。结论　超声能敏感地发现关节滑膜和肌腱端病变的变化情况,可作为这些软组织病变的常规监测手段,用于Sp A患者病情的追踪和临床疗效的评价     

Effects of methylprednisolone and betamethasone injections on the rotator cuff: an experimental study in rats

Thirty-one female Sprague-Dawley rats were used to determine the effects of subacromial corticosteroid injections on the rotator cuff. The injection technique was tested in 6 animals, which were excluded from the study. The remaining 25 rats were randomly divided into three groups of 8 animals each; a single rat received no injections. Every other week for 8 weeks, one shoulder in each rat was injected with methylprednisolone, betamethasone, or saline in a dosage equivalent to that used in humans. The supraspinatus and infraspinatus tendons were removed 10 days after the last injection and evaluated. There were no pathologic changes in the tendons injected with saline. In 43% of the methylprednisolone-treated rats and 29% of the betamethasone-treated rats, the tendons were abnormally soft and light-colored. In 43% of the methylprednisolone group and 71% of the betamethasone group, fragmentation of collagen bundles and inflammatory cell infiltration were evident. Subacromial injections of methylprednisolone or betamethasone repeated frequently can cause deleterious changes in the normal structure of the rat rotator cuff. In light of these findings, therapy for subacromial impingement syndrome of the shoulder with frequent, repeated steroid injections is potentially harmful.     

Mechanical properties of collagen fascicles from in situ frozen and stress-shielded rabbit patellar tendons

OBJECTIVE: To know the effects of stress shielding on the biomechanical properties of collagen fascicles obtained from in situ frozen patellar tendons (an autograft model). DESIGN: Collagen fascicles of approximately 300 microm in diameter were obtained from in situ frozen rabbit patellar tendons and also from in situ frozen and stress-shielded ones, and their mechanical properties and fibroblast density were determined. BACKGROUND: Stress shielding changes the mechanical properties of in situ frozen patellar tendons in which there exist no fibroblasts. The mechanisms of this phenomenon have not been studied well. METHOD: Patellar tendons of both in situ frozen group and in situ frozen and stress-shielded group were frozen in situ by liquid nitrogen to kill fibroblasts. Then, in the in situ frozen and stress-shielded group, no tension was applied to the tendons for 2, 3, and 6 weeks, while normal tension was applied to the tendons of the in situ frozen group. Tensile properties of the collagen fascicles obtained from these tendons were determined using a microtensile tester, and were compared to the collagen fascicles from non-frozen, stress-shielded patellar tendons. RESULTS: Tangent modulus and tensile strength of collagen fascicles from the in situ frozen and stress-shielded group progressively decreased with the time of stress shielding; however, these decreases were much smaller than those of the fascicles obtained from non-frozen, stress-shielded tendons. Although there were few fibroblasts in the patellar tendon of the in situ frozen and stress-shielded group at 2 weeks, the modulus and strength of the fascicles from the posterior portion were significantly lower than those in the in situ frozen group. In addition, the reduction of strength caused by stress shielding was much smaller in collagen fascicles than in bulk patellar tendons. CONCLUSION: The mechanical properties of collagen fascicles in in situ frozen tendons (an autograft model) are affected by stress shielding even under acellular condition.RelevanceThe in situ frozen, stress-shielded patellar tendon is a model of augmented autografts which are clinically used for the reconstruction of injured anterior cruciate ligaments. The sub-macroscopic studies of the tendon are useful to understand the mechanisms of the reduction of graft strength and its gradual recovery observed after reconstruction.     

Effects of growth on the response of the rabbit patellar tendon to stress shielding: a biomechanical study

OBJECTIVE: To know the effect of stress deprivation on the dimensions and mechanical properties of the patellar tendon during growth. DESIGN: The dimensions and tensile properties of stress-shielded patellar tendons were studied in growing rabbits and compared to those in mature animals. BACKGROUND: Although the effects of stress deprivation on the remodeling of ligaments and tendons have been studied in various animal models, the effect of growth on the remodeling has not been studied well. METHOD: A stress shielding technique was applied to 1-, 2-, and 3-month-old Japanese white rabbits to completely remove stress in the patellar tendons for 4, 7, and 14 days. Changes in the dimensions and mechanical properties as well as fibroblast density of the tendon were determined. RESULTS: The tensile strength and tangent modulus of the patellar tendons were markedly decreased by stress shielding, while the cross-sectional area was significantly increased, with the largest changes in 1-month-old rabbits. Fibroblast density also increased; however, the degree of increase was highest in 3-month-old rabbits. CONCLUSION: The changes in the dimensions and mechanical properties of the patellar tendons induced by stress shielding were greater in younger animals. RELEVANCE: The biomechanical response of tendons and ligaments to stress deprivation induced by, for example, limb immobilization is greater and occurs earlier in younger subjects, which is important for the surgical treatment and rehabilitation protocol of joint diseases in young subjects.     

Evaluation of passive and active rehabilitation and of tendon repair for partial tendon lacerations after three weeks of healing in canines

BACKGROUND: Both passive and active rehabilitation have been shown to be superior to immobilization following partial tendon laceration, but few studies have directly compared these two rehabilitation protocols. In addition, controversy still remains over whether a partial tendon laceration should be repaired. METHODS: We evaluated gap formation, adhesions, gliding function and structural properties of repaired and unrepaired tendons following 3 weeks of unrestricted active rehabilitation versus passive mobilization for partial laceration of canine flexor digitorum profundus tendons. An ex vivo radiographic method was used to measure tendon excursion and rotation at each finger joint. The tendon was examined for adhesions, and gapping was measured with calipers. The tendons were tensile tested to failure. FINDINGS: We found no significant differences in tendon excursion, total joint rotation, or adhesions between any groups. Gap size was higher with active mobilization. We found no effect of rehabilitation protocol on the strength or stiffness of healing tendons at 3 weeks. Tendon repair did not affect tendon strength, but did produce higher stiffness in healing tendons at 3 weeks. INTERPRETATION: The results indicate that active rehabilitation appears safe for partial lacerations less than 60 percent. Though repair appears to weaken the tendon in the early stages of healing, it may provide some biomechanical benefit by the middle stages of healing.     

The effects of substance P on the biomechanic properties of ruptured rat Achilles' tendon

OBJECTIVE: To determine whether injection of substance P into the paratendinous region of a ruptured and subsequently sutured rat Achilles' tendon alters the biomechanic properties of the tendon. DESIGN: Interventional animal study. SETTING: Animal laboratory at a university hospital. ANIMALS: Ninety-six 2-month-old, male Sprague-Dawley rats. INTERVENTION: Injection of saline, substance P (10(-6)micromol/kg of body weight [BW] or 10(-8)micromol/kg BW) associated with neutral endopeptidase inhibitors, or neutral endopeptidase inhibitors alone into the paratendinous region of ruptured and subsequently sutured rat Achilles' tendons from the second until the sixth day postoperatively. MAIN OUTCOME MEASURES: Stress at maximal load and work to maximal load and stiffness. RESULTS: Stress at maximal load was higher in the groups injected with substance P than in the saline group in the first, second, and sixth weeks. Work to maximal load was higher from the second until the sixth weeks in the substance P-treated groups than in the saline group. Stiffness did not differ between the 4 groups in any of the weeks. CONCLUSIONS: Injection of substance P into the paratendinous region of ruptured and subsequently sutured rat Achilles' tendons improved tendon healing by enhancing stress at maximal load and work to maximal load. However, stiffness was not significantly affected.     

碳化二亚胺交联改性脱细胞异种猪肌腱修复跟腱缺损

背景：异体肌腱移植是目前修复肌腱缺损的理想方法,但移植后的排斥反应使其使用受到限制.目的：观察碳化二亚胺交联改性脱细胞处理的版纳近交系微型猪肌腱移植修复兔跟腱缺损的效果.方法：横向切除40只日本大白兔双侧跟腱,随机分组：实验组以碳化二亚胺交联改性脱细胞版纳近交系微型猪肌腱移植修复,对照组以自体肌腱移植修复.结果与结论：①组织学观察：两组新生组织内细胞主要都是单核的成纤维细胞和纤维细胞,术后1-4周主要是呈椭圆形或圆形的成纤维细胞,细胞聚集区的细胞周围有新生胶原形成,这些胶原的走向较紊乱;局灶性条索状成熟胶原呈岛状分布,形成所谓“胶原岛”;术后12周时细胞越来越拉长,成为梭形和长条形的纤维细胞.②实验室检测：两组白细胞、C-反应蛋白水平、羟脯氨酸含量及抗拉强度差异均无显著性意义.说明碳化二亚胺交联改性的脱细胞版纳近交系微型猪肌腱能成功修复兔跟腱缺损,且具有组织相容性好、移植排斥反应轻、生物力学性能强的优点.     

Sensory responses to mechanically and chemically induced tendon pain in healthy subjects

This investigation aimed to quantify and compare sensory responses to hypertonic saline‐induced pain in the tendoachilles and the common extensor tendon of the elbow. Healthy subjects (n =14; seven males) received in randomised order, injections of sterile saline (0.5 ml, 5.8% hypertonic or 0.9% isotonic saline) at each tendon bilaterally at two sessions separated by one week. Mechanical sensitivity (pressure pain threshold), muscle pain intensity (visual analogue scale; VAS area‐under‐curve, pain duration, peak pain) and pain distribution were assessed pre, immediately after and post saline injection. Hypertonic saline‐induced pain intensity (VAS area‐under‐curve, duration and peak) was significantly greater compared with control injections (P <0.001) and induced significantly greater VAS area (P <0.01) and longer pain duration (P <0.001) in tendoachilles compared with the common extensor tendon. Regardless of saline type and compared with pre and post injection, mechanical sensitivity increased significantly (P <0.01) immediately after injections at all injected tendon sites. Hypertonic saline‐induced referred pain was infrequent (tendoachilles: n =3 and common extensor tendon: n =4). Significant maximal force attenuation occurred immediately after hypertonic saline injections in both tendons (P <0.001) compared with control injections. The greater induced deep tissue pain and hyperalgesia demonstrated at tendoachilles compared with the common extensor tendon may relate to anatomical differences such as higher nociceptor density or increased vascular perfusion at the injection site. This translational tendon pain model may contribute to the further understanding of pain mechanisms in tendinopathic conditions.     

Sonographically guided flexor hallucis longus tendon sheath injection.

OBJECTIVE: The purpose of this study was to describe a sonographically guided technique to perform flexor hallucis longus (FHL) tendon sheath injections. METHODS: Scans were performed with an intermediate-frequency (7.5- to 12-MHz) linear transducer with the scan plane corresponding to the anatomic axial plane and the patients positioned prone. The transducer was placed along the posteromedial ankle with the needle entry point being lateral to the Achilles tendon. A 25-gauge, 1.5-in needle or a 22-gauge spinal needle was positioned directly into the tendon sheath during real-time visualization with injection of a standardized therapeutic mixture (anesthetic and long-acting corticosteroid) at the level of the posterior sulcus for the FHL. Distention of the tendon sheath during real-time visualization was considered a successful injection. RESULTS: Twenty-four injections in 20 patients (12 female and 8 male; age range, 22-64 years) were performed with this technique. In each case, distention of the FHL tendon sheath was obtained as the desired end point. Apart from minor paresthesias from local anesthesia, no long-term complications from these injections have occurred to date. CONCLUSIONS: We describe a method to perform sonographically guided injections of the FHL tendon sheath. Sonography provides several distinct advantages as a method to provide guidance for delivery of therapeutic injections. The most important of these is the ability to visualize the needle and make adjustments in real time to ensure that medication is delivered to the appropriate location. Given these advantages, we propose that sonographic guidance provides an excellent alternative in the administration of corticosteroids to the FHL tendon sheath.     

US guided corticosteroid injection into the subacromial-subdeltoid bursa: Technique and approach

Local injection of cortisone derivatives, sometimes combined with local anesthetics, is frequently administered in rheumatology as the treatment of choice in para-articular diseases or as an adjuvant to systemic therapy in the treatment of arthritis.One of the most frequent local corticosteroid injections administered in daily clinical practice by rheumatologists, orthopedic surgeons, physiatrists, sports medicine doctors and general practitioners is injection into the subacromialsubdeltoid bursa in the treatment of bursitis and anterior superior impingement syndrome of the shoulder.Before local corticosteroid injection is administered, it is important to identify possible contraindications and to examine the documentation provided by the patient. Absolute contraindications or those related to the procedure should be evaluated by the prescribing physician but also the physician performing the corticosteroid injection should evaluate possible contraindications to make sure that corticosteroid injection is feasible. The present paper describes the ultrasound (US) guided local corticosteroid injection procedure with particular attention to the equipment required, the position of the patient and the examiner as well as the approach. The main advantage of US guidance during corticosteroid injection is the possibility to identify vascular structures, nerves and tendons situated in the needle path in order to avoid these structures and be sure to inject the drug into the appropriate location. When all rules are complied with and the corticosteroid injection is carried out by an experienced physician, it is virtually painless and is performed in just a few minutes.     

甘油常温保存肌腱的两种方法比较

背景：最大程度保留肌腱的生物活性是进行同种异体肌腱移植的条件。目的：通过比较选择出最佳的肌腱常温保存方法。方法：使用无菌操作的方法将兔肌腱随机分为4组：新鲜肌腱对照组、生理盐水组、无水甘油Ⅰ组（肌腱梯度脱水后在无水甘油中保存）、无水甘油Ⅱ组（肌腱直接在无水甘油中保存）,分别于保存的第2,4,7个月进行检测。结果与结论：苏木精-伊红染色显示：无水甘油Ⅰ组肌腱细胞完整率明显高于无水甘油Ⅱ组。电镜观察发现,无水甘油Ⅰ组大部分肌腱细胞形态正常,肌腱组织结构完整;无水甘油Ⅱ组保存4,7个月后细胞核凝固、固缩、崩解状。无水甘油Ⅰ组的超氧化物歧化酶活性也明显高于无水甘油Ⅱ组。说明肌腱经梯度脱水后在无水甘油中常温保存效果更佳。     

转化生长因子β1中和抗体对转化生长因子β诱导肌腱胶原和术后粘连的影响

背景:研究表明,转化生长因子β1在肌腱损伤愈合过程中增加了肌腱细胞胶原的合成和术后粘连的形成.目的:观察转化生长因子β1抗体对转化生长因子β诱导的肌腱细胞胶原产生及术后粘连形成的影响.设计、时间及地点:随机分组观察实验,于2005-09/2006-06在同济医学院实验动物中心完成.材料:选择2-5月龄新西兰大白兔,体质量3.5～4.5 kg.转化生长因子由美国SantaCruz B iotechnology公司提供.方法:取兔屈指肌腱分离肌腱成纤维细胞、腱外膜细胞和腱内膜细胞,将细胞随机分成2组,实验组加入1 μg/L转化生长因子β后,再加入0.1,0.5,1.0mg/L转化生长因子β1中和抗体,对照组不添加任何试剂,酶联免疫吸附实验测定Ⅰ型胶原.取84只兔行中趾屈指肌腱切断吻合术,将其中36只兔随机分成3组,腱鞘内分别注入生理盐水、1.0,2.0 mg/L转化生长因子β1中和抗体,4,8周后取出肌腱行肌腱粘连检测、生物力学测定、组织学观察和扫描电镜观察;余48只兔随机分成2组,腱鞘内分别注入生理盐水和1.0mg/L转化生长因子β1中和抗体,1,2,4,8周后取出肌腱,原位杂交方法测定肌腱转化生长因子β1和Ⅰ型胶原mRNA的表达.主要观察指标:各组兔肌腱细胞胶原产生及术后粘连情况.结果:酶联免疫吸附实验显示,转化生长因子β1能明显提高肌腱细胞Ⅰ型胶原的产生;转化生长因子β1抗体能降低3种细胞Ⅰ型胶原的产生,随抗体质量浓度增加,Ⅰ型胶原水平逐渐降低,且呈剂量依赖性;术后4,8周,与1.0,2.0mg/L转化生长因子β1组比较,生理盐水组屈趾肌腱滑动距离较短,模拟主动屈曲度明显受限(P<0.05),最大抗断裂载荷各组间比较差异无显著性意义(P>0.05).扫描电镜和组织学观察结果显示,术后4,8周生理盐水组胶原纤维排列紊乱,1.0,2.0 mg/L转化生长因子β1组胶原纤维排列整齐.原位杂交结果显示,术后各时间点1.0 mg/L转化生长因子β1组转化生长因子β1和Ⅰ型胶原mRNA表达均低于生理盐水组(P<0.05).结论:转化生长因子β1抗体能有效抑制转化生长因子β1在肌腱损伤修复中的作用,减少粘连形成.     

Tendon regeneration induced by umbilical cord graft in a rabbit tendon defect model

Whether tendon regeneration can be induced using the umbilical cord as a whole‐graft structure is unknown. In this study, we explored the potential for tendon regeneration induction using an umbilical cord graft in a rabbit model of patella tendon defects. In 52 of 54 New Zealand White rabbits, the central third of the patella tendons of both hind legs was removed to create tendon defects. The rabbits were randomly divided into four groups, nonfilling (empty defect), refilling (defect refilled with resected tendon portion), Wharton's jelly (WJ) outside (WJO; defect filled with umbilical cord graft, WJ side facing outward), and WJ inside (WJI; same as WJO with WJ side facing inward) groups. Four rabbits from WJO and WJI groups were sacrificed for human CD 105 evaluation 1 month after surgery. Further histological, biomechanical, and gene expression analyses were performed at 3 and 6 months after surgery. The untreated patella tendons in the remaining two rabbits were harvested as normal biomechanical controls. Histological evaluation showed that the formed tissue structure fibers in the tendon defect area were much denser and more mature in the WJI group than in all other groups. Biomechanical testing showed that the failure load of the final tissue structure was the highest in the WJI group. Real‐time polymerase chain reaction indicated that the expression of most tendon‐related genes was upregulated in the WJI group at 6 months after surgery. We concluded that umbilical cord grafting induces effective tendon regeneration, particularly when the WJ side faces inward.     

Optimum location of knot for tendon surgery in side-locking loop technique

BACKGROUND: Although various tendon repair techniques have been reported to achieve stronger repair, suture failures tend to occur near the knot. We experimentally investigated whether the location of a single core suture knot affects the biomechanical properties of the repair. METHODS: Transected bovine tendons (male Japanese black cattle, 24 months old) of the medial gastrocnemius (9-11 x 14-16 mm in diameter) were sutured with the side-locking loop technique using a USP2-sized polyethylene and polyester multifilament suture or polyester multifilament suture. The knot was made using 7 simple square ties (a surgeon's knot plus 5 ties) at three locations; on the loop, between the tendon stumps, or between the loops burying the knot in a tendon slit using a scalpel. A cyclical loading protocol from 10N to 100N was used and the loading was repeated 10,000 times. FINDINGS: The gap was most decreased and the ultimate strength was most increased when the knot was located between the loops when using a polyethylene and polyester multifilament suture. Cross-sectional area of the tendon showed the ratio of the buried knot relative to the tendon was only 1.6-2.3%, and the polyethylene and polyester multifilament suture was very durable against frictional abrasion. INTERPRETATION: We found that the knot between the loops, buried in the bovine tendon provided the optimum results.