Articular cartilage degeneration after acute subchondral bone damage: an experimental study in dogs with histopathological grading

BACKGROUND: Subchondral fracture patterns and bone bruises have been described and some clinical studies have shown alterations in the initially healthy cartilage after such lesions. METHODS AND RESULTS: After having performed cadaver studies, we created an animal model to produce pure subchondral damage without affecting the articular cartilage, under MRI control. We used 12 beagle dogs. For quantification of different degrees of staining, we used a grading of the sections by means of the HHGS (Histological-Histochemical Grading System) or Mankin score. RESULTS: In all cases, FLASH 3D sequences revealed intact cartilage in MRI after impact. The best detection of subchondral fractures was achieved in fat-suppressed TIRM sequences. Image analysis based on the HHGS showed changes in 10 of 12 samples, with a high degree of significance 6 months after the initial trauma. Correlation analysis showed loss of the physiological distribution of proteoglycans and glycoproteins in the different zones of articular cartilage. Subcategories "Structure", "Cells" and "Safranin-O Staining" also showed high significance, and the category "Tidemark Integrity" showed a tendency. INTERPRETATION: Our findings indicate that acute subchondral fractures are a predictor of degenerative changes within 6 months. Modifications and supplements to rehabilitation might be needed in cases with accompanying subchondral lesions, e.g. in ACL tears.     

Articular cartilage degeneration after acute subchondral bone damage An experimental study in dogs with histopathological grading

Background Subchondral fracture patterns and bone bruises have been described and some clinical studies have shown alterations in the initially healthy cartilage after such lesions. Methods and results After having performed cadaver studies, we created an animal model to produce pure subchondral damage without affecting the articular cartilage, under MRI control. We used 12 beagle dogs. For quantification of different degrees of staining, we used a grading of the sections by means of the HHGS (Histological-Histochemical Grading System) or Mankin score. Results In all cases, FLASH 3D sequences revealed intact cartilage in MRI after impact. The best detection of subchondral fractures was achieved in fat-suppressed TIRM sequences. Image analysis based on the HHGS showed changes in 10 of 12 samples, with a high degree of significance 6 months after the initial trauma. Correlation analysis showed loss of the physiological distribution of proteoglycans and glycoproteins in the different zones of articular cartilage. Subcategories “Structure”, “Cells” and “Safranin-O Staining” also showed high significance, and the category “Tidemark Integrity” showed a tendency. Interpretation Our findings indicate that acute subchondral fractures are a predictor of degenerative changes within 6 months. Modifications and supplements to rehabilitation might be needed in cases with accompanying subchondral lesions, e.g. in ACL tears.     

The fate of meniscus cartilage after transplantation of cryopreserved nontissue-antigen-matched allograft. A case report.

A cryopreserved nontissue-antigen-matched meniscus was transplanted in the knee of a 48-year-old man with lateral compartment osteoarthrosis. After six months, diagnostic arthroscopy was performed. Clinical, histologic, and histochemical studies showed that meniscal chondrocytes survived cryopreservation and transplantation. One year after surgery, the outline of the donor meniscus on an arthrogram appeared normal.     

Articular cartilage restoration in load-bearing osteochondral defects by implantation of autologous chondrocyte-fibrin constructs: an experimental study in sheep

Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous 'chondrocyte-fibrin' construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis. All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O'Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage. Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.     

同种异体切削软骨移植──动物实验观察

新鲜块状猪肋软骨及切成２ｍｍ×１ｍｍ的片状软骨异体移植，同时行相对应的块状及片状异体猪肋软骨经０．４％戊二醛、甲醛混合液库存４周后的同期移植，移植后分别于１、３、５个月取材。取材样本分别行组织、组化、生物化学、电镜及显微图象定量分析手段研究与测定。结果提示，新鲜异体软骨移植物主要发生了血管化及吸收性改变，移植效果差，而经保存液处理的块状及片状移植物未见明显的血管侵袭及吸收性改变，主要发生了钙化性退变，尤其是片切软骨更为显著。结果显示库存软骨移植物的组织、组化、形态学及基质中胶原含量变化存在一定规律。本实验结果提示：切削与雕刻因素是造成软骨移植物退变的一种重要原因，但是经保存液处理的切削软骨行异体移植时具有一定的整形外科支架优势     

微孔聚已内酯膜对异体肌腱移植后粘连的预防作用

目的研究微孔聚己内酯(PCL)薄膜对同种异体肌腱移植后粘连的预防作用,并探讨其对肌腱愈合的影响。方法选用在-84℃冰箱冻存10d的兔同种异体肌腱移植于30只受体兔右下肢肌腱缺损处,随机分为2组,A组在腱移植处包裹微孔PCL薄膜作为实验组,B组在腱移植处不包裹薄膜作为对照组。术后不同时间,切取腱移植部位,进行大体观察,常规制成光、电镜标本,镜下观察;对移植腱段、吻合口进行羟脯氨酸(HyP)含量及腱周粘连定量测定。结果镜下微孔PCL包膜组腱移植段内部的成纤维细胞数和胶原纤维量与不包膜组无明显差别,但不包膜组腱周组织成纤维细胞数和胶原纤维量明显较微孔PCL包膜组多;HyP含量不包膜组与微孔PCL组差异无统计学意义(P>0.05),移植腱段和吻合口的羟脯氨酸含量,微孔PCL组分别为(27.3±3.5)mg/g体重,(19.2±3.8)mg/g体重;未包膜组为(28.4±3.6)mg/g体重,(20.1±3.2)mg/g体重;不包膜组比微孔PCL组粘连程度重(P<0.05)。结论微孔PCL膜有预防肌腱粘连的作用,对肌腱愈合无影响,临床可作为一种预防肌腱粘连措施。     

脱细胞基质同种异体半月板移植的实验研究

目的 :探索同种异体半月板移植中移植半月板的处理方法 ,提高同种异体半月板移植效果。方法 :大耳白兔分为半月板供体组和受体组。供体组右内侧半月板低温冻存 ( -80℃ ) ,左内侧半月板进行脱细胞处理 (不用曲拉通X -10 0 )。将供体半月板移植到异体关节内 ,分批做大体、组织学、影像学观察。结果 :左侧半月板较右侧萎缩轻 ,关节面破坏程度轻 ,组织学和影像学检查均有统计学意义。结论 :经脱细胞处理 (不用曲拉通X -10 0 )的半月板同种异体移植较普通低温冻存半月板移植较果好     

Soft tissue and tendon reconstruction after achilles tendon rupture: adipofascial sural turnover flap associated with cryopreserved gracilis tendon allograft for complicated soft tissue and achilles tendon losses. A case report and literature review

Soft tissue and tendon reconstruction after Achilles tendon rupture:Adipofascial sural turnover flap associated with cryopreserved gracilis tendon allograft for complicated soft-tissue tendon losses.A case report and literature review Achilles tendon rupture is often complicated by skin substance loss around the tendon, which is a poorly-vascularized site. Treatment may be conservative or surgical, but the former is not generally accepted by the orthopedic community and is reserved for selected cases, while surgery remains the most widely-used approach. Soft tissue repair at this site is a crucial reconstruction problem, and becomes very complex if skin reconstruction has to be associated with a complex tendon repair. The Authors describe a new approach to the repair of Achilles tendon substance loss compounded by a soft tissue defect, using a cryopreserved gracilis tendon allograft in combination with a distally-based adipofascial sural flap.     

The protective effects of meniscal transplantation on cartilage. An experimental study in sheep

BACKGROUND: Meniscal loss may result in arthritis. The aim of this study was to establish a simple operative method for meniscal transplantation in a large-animal model and to determine whether meniscal transplantation provides protection of the articular surfaces, whether meniscal allografts have the same protective effect as meniscal autogenous grafts, and whether there is any rejection phenomenon associated with meniscal allografts. METHODS: Twenty-eight sheep were divided into four study groups, which were treated with (1) a sham operation (four sheep), (2) a meniscectomy (eight sheep), (3) a meniscal autogenous graft (eight sheep), or (4) a meniscal allograft (eight sheep). The meniscal transplant was secured with three suture anchors to the tibia. At four months after the operation, macroscopic and microscopic evaluations of the articular cartilage and the menisci of the sheep knees were performed in a blinded fashion. RESULTS: The group treated with the sham operation had no cartilage damage and had normal meniscal tissue. The meniscectomies resulted in significant macroscopic and microscopic damage to the articular cartilage in the medial compartment. The mean score (and standard error of the mean) for macroscopic damage to the cartilage in the group treated with the meniscectomy was 6.5+/-0.8 points compared with 3.9+/-0.7 points in the group treated with the autogenous graft and 4.3+/-0.6 points in the group treated with the allograft (p<0.05). The size of the area of damaged articular cartilage was reduced by approximately 50 percent in both groups treated with a meniscal transplant compared with the group treated with the meniscectomy (p<0.05). There were no significant differences between the group treated with the autogenous graft and that treated with the allograft. The histological appearance of the meniscal autogenous grafts was within normal limits. Interestingly, all of the allografts had evidence of fibrinoid degeneration with areas of hypocellularity and cloning of chondroid cells. CONCLUSIONS: These results suggest that meniscal transplantation provides noticeable although not complete protection against damage to the articular cartilage after a meniscectomy. The meniscal allografts were just as effective in providing this protection as were the meniscal autogenous grafts.     

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。     

The tips and pitfalls of meniscus allograft transplantation

When faced with an irrepairable meniscus or a patient who has had a total or subtotal meniscectomy, meniscus allograft transplantation (MAT) is the preferred modality to restore biomechanical function of the meniscus. The indications for meniscus allograft transplantation are yet to be established. However, currently, MAT has previously been indicated for symptomatic patients who have mild or early osteoarthritis, are younger than 50 years of age, and present with an Outerbridge grade II or lower. The short- to intermediate-term results confirmed noteworthy clinical improvements and consistent objective findings. On the other hand, the successful outcome would be reduced by various complications. Therefore, long-term observation required to evaluate the longevity of these results. The purpose of this article is to review the current research of concerns on the results of MAT, and to describe the technical tips and pitfalls so as to successful clinical results.     

Enveloping bioabsorbable polyglycolide membrane and immobilization in achilles tendon repair: A comparative experimental study on rabbits

Using qualitative and histoquantitative methods, we investigated the effect of immobilization versus nonimmobilization on the biodegradation process, implant‐tissue interaction, and scar formation after enveloping a rejoined rabbit Achilles tendon with a self‐reinforced polyglycolide (SR‐PGA) membrane. The soleus and gastrocnemius tendons of the right hind legs of 40 rabbits were transected. After suturing the ends, the seam was enveloped with the bioabsorbable membrane. Twenty ankles were immobilized with cast, 20 remained nonimmobilized. All nonoperated left ankles served as intact controls. During the follow‐up of 3, 6, 12, and 24 weeks, scar formation, tissue response, and membrane biodegradation were studied histologically and histomorphometrically. The amount of scar tissue, highest at 3 weeks, gradually approached intact controls. SR‐PGA degradation in both cast and noncast specimens was near complete by 24 weeks. Signs of an inflammatory process were most prominent at 3 weeks and diminished gradually by 24 weeks. No significant difference between cast and noncast specimens was noted at any time point regarding the amount of scar tissue, degradation process of PGA, or intensity of inflammatory reaction. In the present experimental setting, cast immobilization influenced neither scar formation nor speed of degradation during reunion of transected Achilles tendon ends as compared with nonimmobilization. No differences in the reunion process of the tendon ends were seen between the immobilized and nonimmobilized groups. Moreover, inflammatory cells were similar in both groups and reflected a transient tissue reaction to the membrane. Within the follow‐up, the seam area (cross‐sectional) approached that of intact controls. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:264–270, 2008     

Cyclic mechanical stimulation rescues achilles tendon from degeneration in a bioreactor system

Physiotherapy is one of the effective treatments for tendinopathy, whereby symptoms are relieved by changing the biomechanical environment of the pathological tendon. However, the underlying mechanism remains unclear. In this study, we first established a model of progressive tendinopathy‐like degeneration in the rabbit Achilles. Following ex vivo loading deprivation culture in a bioreactor system for 6 and 12 days, tendons exhibited progressive degenerative changes, abnormal collagen type III production, increased cell apoptosis, and weakened mechanical properties. When intervention was applied at day 7 for another 6 days by using cyclic tensile mechanical stimulation (6% strain, 0.25 Hz, 8 h/day) in a bioreactor, the pathological changes and mechanical properties were almost restored to levels seen in healthy tendon. Our results indicated that a proper biomechanical environment was able to rescue early‐stage pathological changes by increased collagen type I production, decreased collagen degradation and cell apoptosis. The ex vivo model developed in this study allows systematic study on the effect of mechanical stimulation on tendon biology. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1888–1896, 2015.     

Centralization of extruded medial meniscus delays cartilage degeneration in rats

Background

Meniscus extrusion often observed in knee osteoarthritis has a strong correlation with the progression of cartilage degeneration and symptom in the patients. We recently reported a novel procedure “arthroscopic centralization” in which the capsule was sutured to the edge of the tibial plateau to reduce meniscus extrusion in the human knee. However, there is no animal model to study the efficacy of this procedure. The purposes of this study were [1] to establish a model of centralization for the extruded medial meniscus in a rat model; and [2] to investigate the chondroprotective effect of this procedure.

Chronic rupture of a patellar tendon: A technique for reconstruction with achilles allograft

Chronic ruptures of the patellar tendon fortunately are an uncommon event. These ruptures are often difficult to repair because they are generally accompanied by quadriceps muscle contracture and a great deal of scar tissue formation. We report the case of a repair of a chronic patellar tendon rupture. The patient's right patellar tendon was reconstructed approximately 10 months after the injury using quadricepsplasty and an Achilles tendon allograft with a suprapatellar wire for tension release. Four weeks postoperatively, he had attained 60° of flexion and full active extension. At 8 weeks, the suprapatellar wire was removed allowing the distribution of stresses on the reconstructed patellar tendon. At 6 months, the patient had 130° of flexion and full extension, but showed a persistent 40% deficit in right quad strength. The technique accomplished the preoperative goals of restoring quadriceps function, restoring the anatomic position of the patella, and allowing early mobilization after surgery. Although the use of a suprapatellar wire to reduce tension on the reconstructed tendon required a second operation for removal, it allowed early mobilization and better healing of the repair.     

Articular cartilage transplantation. Clinical results in the knee

Between December 1983 and August 1991, 55 consecutive patients (55 knees) who underwent articular cartilage transplantation to their damaged knees were enrolled in the study. Average followup was 75 months (range, 11-147 months). Eight-two percent were younger than 45 years of age. Patients were evaluated through an 18-point scale, with 6 points each allocated to pain, range of motion, and function. An excellent knee was pain free, had full range of motion, and permitted unlimited activity. A good knee allowed full time employment and moderate activity. Eleven of 15 (73%) allografts transplanted 10 or more years ago were still good or excellent at the time of last followup. Overall, 45 of 55 (76%) knees that received the transplants were rated good or excellent. Specifically, 36 of 43 (84%) patients with unipolar transplants regained normal use of their resurfaced knee. The results after bipolar resurfacing were less encouraging, with only six of 12 (50%) knees rated good or excellent. The described technique of osteochondral shell allograft resurfacing of the knee capitalize on the different healing potentials of bone and cartilage by transplanting the viable articular cartilage organ in its entirety along with just enough of the underlying bone to allow for graft incorporation through creeping substitution. The results support the use of fresh osteochondral shell allograft transplantation for the treatment of large, full thickness articular cartilage defects to the medial or lateral femoral condyles and to the patella.     

Articular cartilage surgery in outpatients: a pilot study

Open knee surgery for the treatment of large symptomatic cartilage defects is routinely performed in the inpatient stay, where the patients are hospitalized for several days after surgery. This has implications for both costs for the health system and medical complications such as hospital-related infections. In this article, we describe for the first time that this type of operation can be performed as outpatient surgery without any complications for the patients and with good clinical results that in our sample do not differ from those reported in larger groups of patients who underwent surgery and were hospitalized thereafter.     

软骨终板钙化与椎间盘退变关系的实验研究

目的　研究椎体软骨终板钙化与椎间盘退变的关系。　方法　通过切除２０ 只兔颈椎棘上、棘间韧带及分离颈椎后旁两侧肌肉造成颈椎力学上的失稳而诱导了颈椎间盘退变动物模型。在形态学上评定颈椎间盘退变程度,测定不同退变程度椎间盘软骨终板钙化层与非钙化层厚度。　结果　软骨终板钙化层厚度与椎间盘退变程度呈高度正相关性（ｒ＝ ０－９２） 。　结论　软骨终板的钙化可能是椎间盘退变的启动和促进因素     

Neurohistological findings after experimental anterior cruciate ligament allograft transplantation

Summary A multiplicity of surgical operations have been developed in an attempt to achieve satisfactory function after anterior cruciate ligament (ACL) repair. None of these procedures have been able to duplicate the fiber organization, anatomy of the attachment site, vascularity, or function of the ACL. Eighteen foxhounds received a deep-frozen bone-ACL-bone allograft and a ligament augmentation device. Neurohistological changes were evaluated 3, 6 and 12 months following implantation. The modified silver impregnation method and gold chloride technique were used to examine the presence of nerve endings and axons. Two morphologically distinct mechanoreceptors were identified and classified as free nerve endings and Golgi-like tendon receptors respectively. Fine nerve endings frequently ramified freely into ligament collagen bundles. Nerves and blood vessels were commonly associated. As in normal ACLs, both neuroreceptor types were mostly located near the surface of the allografts and at the two bony attachments. This study demonstrated the first histological evidence of viable mechanoreceptors and free nerve endings in transplanted ACL allografts, not previously reported in other ACL substitutes used for ACL reconstruction. Particularly importantly for postoperative rehabilitation, this technique may allow the reconstruction of the proprioceptive functions of normal ACLs.