Value of osteo-chondral paste autologous transplantation in experimental cartilage defects reconstruction. Part III--Microscopic analysis of reconstructed cartilage thickness and surface regularity]

INTRODUCTION: A limited ability of the cartilage to heal after trauma was the reason to start research on new methods concerning better cartilage reconstruction. The aim of the study was evaluation of repair tissue thickness and surface regularity after osteochondral paste transplantation. MATERIAL AND METHODS: Full thickness defect (IV(o)--ICRS scale) on distal rabbit femur joint surface was made. Three groups were specified: A--defect with paste graft (cartilage and contiguous bone collected from joint surface, crushed into homogenous paste; B--defect with the paste graft covered with periosteum; C--defect left unfilled. The follow-up periods were established at 4, 8, 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: Newly formed tissue was well integrated with surrounding cartilage in group A (paste graft). That trait of repair tissue in group A was much better than in other groups, especially in late observations. Structural integrity of tissue filling the defect was similar to integrity of normal cartilage in groups A and C, but tissue formed in group C didn't represent a hyaline-like cartilage character. In all the examined groups reconstruction of subchondral bone exhibited similar rate. 12 weeks from the procedure, around 80% of subchondral bone was rebuilt. The obtained results indicate, that osteochondral paste autologous transplantation in cartilage defects treatment effects with forming well integrated (structurally and with surrounding cartilage) cartilage tissue, of almost complete subchondral bone rebuilding.     

Value of autologous chondrocyte transplantation in experimental cartilage defects reconstruction. Part III--Microscopic analysis of reconstructed cartilage thickness and integration with surrounding tissue]

Lack of cartilage vascularization is the reason of its low regenerative potential. The aim of this part of the study was microscopic evaluation of repair tissue thickness and its integration with surrounding cartilage, after autologous chondrocyte transplantation. MATERIAL AND METHODS: Repair of partial thickness cartilage defect (ICRS III(o) grade) on distal femur joint surface was evaluated (25 adolescent rabbits). Procedures were performed in two groups: I--autologous chondrocyte transplantation under periosteal flap, II--periosteal graft. Chondrocytes were isolated from the cartilage specimens by enzymatic digestion and cultured in vitro. The follow-up periods were established at 4, 8, 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: In group I, 8 weeks after the procedure most of defects were filled with the newly formed tissue almost completely. Regenerate thickness after 4 and 12 weeks usually exceeded 1/2 of surrounding cartilage. In group II, 8 weeks after the procedure regenerate thickness amounted to at least 1/2 of surrounding cartilage, but 4- and 12-week observation revealed the decreased repair tissue thickness. In group I, 4 weeks after the procedure regenerative tissue was well integrated with surrounding cartilage, and this trait still gradually increased with time. In group II, there was partial integration or no integration of repair tissue with surrounding cartilage. CONCLUSION: Obtained results indicate, that tissue formed after autologous chondrocyte transplantation with use of periosteal flap was better in its thickness and integration with surrounding cartilage, as compared to tissue formed after use of periosteum alone. Autologous chondrocyte transplantation can not guarantee complete filling of the cartilage defect with the graft tissue and full integration with surrounding cartilage, without three-dimensional scaffold application.     

Value of autologous transplantation of osteo-chondral paste in reconstruction of experimental cartilage defects. Part II. Microscopic analysis of integration with surrounding cartilage, structural integrity and subchondral bone reconstruction in repair tissue]

INTRODUCTION: A limited ability of the cartilage to heal after trauma was the reason to start research on new methods concerning better cartilage reconstruction. The aim of the study was evaluation of repair tissue integration with surrounding cartilage, its structural integrity and subchondral bone reconstruction after osteo-chondral paste transplantation. MATERIAL AND METHODS: Full thickness defect (IV degree--ICRS scale) on distal rabbit femur joint surface was made. Three groups were specified: A--defect with paste graft (cartilage and contiguous bone collected from joint surface, crushed into homogenous paste; B--defect with the paste graft covered with periosteum; C--defect left unfilled. The follow-up periods were established at 4, 8, 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: Newly formed tissue was well integrated with surrounding cartilage in group A (paste graft). That trade of repair tissue in group A was much better than in other groups, especially in late observations. Structural integrity of tissue filling the defect was similar to integrity of normal cartilage in groups A and C, but tissue formed in group C didn't represent a hyaline-like cartilage character. In all the examined groups reconstruction of subchondral bone exhibited similar rate. 12 weeks from the procedure, around 80% of subchondral bone was rebuilt. The obtained results indicate, that osteo-chondral paste autologous transplantation in cartilage defects treatment effects with forming well integrated (structurally and with surrounding cartilage) cartilage tissue, of almost complete subchondral bone rebuilding.     

Value of autologous chondrocyte transplantation in the reconstruction of experimental cartilage defects. Part I. Extent of defect, macroscopic appearance of reconstructed articular surface and microscopic analysis of predominant tissue]

Articular cartilage defect is one of the main reasons of osteoarthritis. Currently, tissue engineering techniques are the methods concerning better cartilage reconstruction. The aim of this part of the study was macroscopic evaluation of degree of defect feeling, macroscopic appearance of repair tissue and microscopic analysis of predominant tissue after autologous chondrocytes transplantation. Repair of partial thickness cartilage defect on distal part of femur was evaluated (25 adolescent rabbits). Procedures were performed in II groups: I--autologous chondrocytes transplantation under periosteal flap, II--periosteal graft. Chondrocytes were isolated from the cartilage specimens by enzymatic digestion and cultured in vitro. The regenerates were inspected 4, 8 and 12 weeks after the operation. Macroscopic analysis in group I, in most cases revealed filling of the defect with tissue resembling surrounding cartilage. In group II the defect was partially filled, and there was many fissures and cracks in all regenerates. In microscopic analysis in group I, after 4 and 8 weeks following the transplantation the tissue similar to juvenile hyaline cartilage predominated. After 12 weeks it resembled mature hyaline cartilage. In group II, in all cases fibrous cartilage was observed after 4, 8, 12 weeks. Obtained results indicate, that macroscopic and microscopic characteristics of repair tissue after autologous chondrocytes transplantation more closely resembled hyaline cartilage, than in periosteal graft group. 12 weeks after autologous chondrocytes transplantation the repair tissue reached maturity, and demonstrated microscopic characteristics of hyaline-like cartilage. The method of autologous chondrocytes transplantation provides potential for clinical application.     

Value of autologous chondrocyte transplantation in experimental cartilage defects reconstruction. Part IV--Microscopic analysis of repair tissue degenerative changes (cellularity and signs of necrosis)]

Articular cartilage cells are immersed in semi-solid matrix and isolated from the rest of the body because of lack of nervous fibres, and blood and lymphatic vessels. Trauma and aging processes result in cartilage ultrastructure disorders. Those changes leads to progressive decreasing of durability and rigidity of cartilage. Research on articular cartilage reconstruction focuses on, among other things, reaching by newly formed tissue optimal amount of vital cells. The aim of this part of the study was microscopic evaluation of repair tissue degenerative changes (cellularity and signs of necrosis). MATERIAL AND METHODS: Repair of partial thickness cartilage defect (III tertiary grade) on distal femur joint surface was evaluated (25 adolescent rabbits). Procedures were performed in two groups: I--autologous chondrocyte transplantation under periosteal flap, II--periosteal graft. Chondrocytes were isolated from the cartilage specimens by enzymatic digestion and cultured in vitro. The follow-up periods were established at 4, 8 and 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: Repair tissue cellularity. In group I (with chondrocytes), 4 weeks after the procedure tissue of high cellularity was formed, corresponding in amount of cells to the structure of early differentiated hyaline-like cartilage. Amount of cells slightly decreased with time, as it occurs in maturing cartilage. In group II (without chondrocytes), 4 weeks after the procedure the repair tissue was characterized by small amount of cells, which was decreasing with time. Signs of necrosis. In group I, 4, 8 and 12 weeks after the procedure moderate intensity of necrotic signs was observed. In group II, significant intensity of necrosis signs in all observation periods was observed. CONCLUSION: Obtained results indicate, that autologous chondrocyte transplantation in treatment of partial thickness cartilage defects effects with forming tissue of high cellularity, not degenerating with time, much better as compared to untreated defect.     

Value of osteo-chondral paste autologous transplantation in experimental cartilage defects reconstruction. Part IV--Microscopic analysis of cellularity and of traits of necrosis in the defect-filling tissue]

INTRODUCTION: Restricted potential of cartilage to regeneration following trauma induced search for new techniques of articular cartilage repair. Present study aimed at defining in experimental conditions of autologous osteochondral paste value by evaluation of cellularity and presence of necrosis in the defect-filling tissue. MATERIAL AND METHODS: Full thickness defect (IV(o)--ICRS scale) on distal rabbit femur joint surface was made. Three groups were specified: A--defect with paste graft (cartilage and contiguous bone collected from joint surface, crushed into homogenous paste; B--defect with the paste graft covered with periosteum; C--defect left unfilled. The follow-up periods were established at 4, 8, 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: In evaluation of cellularity in the developed repair tissue, in long-term observations best results were obtained in the group of osteochondral paste (A) and in the group of unfilled defect (C). Following 12 weeks of observation cellularity of the repair tissue in the groups amounted to around 95%, as compared to the surrounding healthy cartilage. In evaluation of necrotic traits in the newly developed tissue, their highest intensity after 4 weeks of observation was noted in the group with periosteum covered osteochondral paste (B), and lower but still significant in the group in which paste alone was applied (A). This resulted from massive dying out of the grafted bone elements, and in the case of group B, also of the periosteal cells in the covering flap and of certain number of chondrocytes composing the graft. The trait was more objectively evaluated in long-term observations, when necrotic foci involved only elements of the proper repair tissue. After 12 weeks of observation degenerative changes showed the least pronounced intensity in the group with the paste alone (A). Following 4 weeks the intensity was least pronounced in the group with the unfilled defect (C), i.a. due to the absence of graft with the decomposing bone elements. However, with elapsing time degenerative lesions intensified in the group, pointing to the low stability of the developed tissue. The results indicated that application of the osteochondral paste in treatment of cartilage defects yields a stable, highly cellular tissue, resistant to time and trauma.     

The repair of experimentally produced defects in rabbit articular cartilage by autologous chondrocyte transplantation

Using the knee joints of New Zealand White rabbits, a baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate. A second experiment examined the effect of autologous chondrocytes grown in vitro on the healing rate of these defects. To determine whether any of the reconstituted cartilage resulted from the chondrocyte graft, a third experiment was conducted involving grafts with chondrocytes that had been labeled prior to grafting with a nuclear tracer. Results were evaluated using both qualitative and quantitative light microscopy. Macroscopic results from grafted specimens displayed a marked decrease in synovitis and other degenerative changes. In defects that had received transplants, a significant amount of cartilage was reconstituted (82%) compared to ungrafted controls (18%). Autoradiography on reconstituted cartilage showed that there were labeled cells incorporated into the repair matrix.     

Repair of porcine articular cartilage defect with autologous chondrocyte transplantation.

Articular cartilage is known to have poor healing capacity after injury. Autologous chondral grafting remains the mainstay to treat well-defined, full-thickness, symptomatic cartilage defects. We demonstrated the utilization of gelatin microbeads to deliver autologous chondrocytes for in vivo cartilage generation. Chondrocytes were harvested from the left forelimbs of 12 Lee-Sung pigs. The cells were expanded in monolayer culture and then seeded onto gelatin microbeads or left in monolayer. Shortly before implantation, the cell-laden beads were mixed with collagen type I gel, while the cells in monolayer culture were collected and re-suspended in culture medium. Full-thickness cartilage defects were surgically created in the weight-bearing surface of the femoral condyles of both knees, covered by periosteal patches taken from proximal tibia, and sealed with a porcine fibrin glue. In total, 48 condyles were equally allotted to experimental, control, and null groups that were filled beneath the patch with chondrocyte-laden beads in gel, chondrocytes in plain medium solution, or nothing, respectively. The repair was examined 6 months post-surgery on the basis of macroscopic appearance, histological scores based on the International Cartilage Repair Society Scale, and the proportion of characteristic chondrocytes. Tensile stress-relaxation behavior was determined from uniaxial indentation tests. The experimental group scored higher than the control group in the categories of matrix nature, cell distribution pattern, and absence of mineralization, with similar surface smoothness. Both the experimental and control groups were superior to the null group in the above-mentioned categories. Viable cell populations were equal in all groups, but the proportion of characteristic chondrocytes was highest in the experimental group. Matrix stiffness was ranked as null > native cartilage > control > experimental group. Transplanted autologous chondrocytes survive and could yield hyaline-like cartilage. The application of beads and gel for transplantation helped to retain the transferred cells in situ and maintain a better chondrocyte phenotype.     

Evaluation of cartilage reconstruction by means of autologous chondrocyte versus periosteal graft transplantation: an animal study

BACKGROUND: Autologous chondrocyte transplantation (ACT) has been shown to heal cartilage defects under experimental and clinical conditions. However, the evaluation of successful transplantation still remains arbitrary and further research is required to establish objective criteria of treatment. The aim of the present study was to evaluate the criteria of successful ACT and to compare the results with those obtained following periosteal grafting (PG). MATERIALS AND METHODS: Articular cartilage specimens were taken from the distal femur of 30 adolescent New Zealand rabbits and chondrocytes were obtained by collagenase digestion. The chondrocytes were identified by a functional assay, based on estimating procollagen type II mRNA by reverse-transcribed polymerase chain reaction. The cells cultured in vitro were transplanted under a periosteal flap into a full thickness defect (ICRS III(0)). The quality of the repaired tissue was evaluated macroscopically according to a modified scale of Brittberg et al, and microscopically according to O'Driscoll et al. For comparative purposes animals treated with PG were used. RESULTS: Cultured chondrocytes expressed procollagen type II and, upon transplantation into the defect, produced hyaline cartilage. To evaluate the results of transplantation, two categories of criteria were adopted-macroscopic analysis and microscopic examination. By all adopted criteria the results were significantly better in the ACT group (P < .05) than in the PG group. CONCLUSION: Prior to transplantation, assays for specialized functions of chondrocytes required semiquantitative evaluation of macroscopic and microscopic appearance of the repaired tissue, showing the benefit of autologous chondrocyte versus periosteal graft transplantation.     

Articular cartilage defects of the distal femur in children and adolescents: treatment with autologous chondrocyte implantation

PURPOSE: Procedures aimed at biologically repairing cartilage injuries may have the greatest potential benefit in young patients because of their long-life expectancy and high-functional demands. Most cartilage-repair studies focus on older patient populations. This study assesses the outcomes of patients who were treated with autologous chondrocyte implantation before the age of 18. STUDY DESIGN: This is a Registry-based, multicenter, observational, cohort study of 37 patients from whom follow-up data was prospectively collected. Patient-rated assessments of overall condition, pain, and swelling were measured using modified, 10-point scales of the Cincinnati Knee Rating System. RESULTS: Mean age was 16 years (11-17); 22 boys and 15 girls. Twenty-three patients underwent at least 1 cartilage repair procedure before the cartilage harvest, including 11 who had a marrow stimulation procedure. Fourteen patients were diagnosed with osteochondritis dessicans lesions. Thirty-five patients had single defects (mean size, 5.4 cm). Thirty-two patients completed self-evaluations at a minimum of 2 years after implantation (mean follow-up = 4.3 years). The mean change in scale scores measuring overall condition, pain, and swelling were 3.8, 4.1, and 3.4 points, respectively. One patient had an implantation that failed. CONCLUSIONS: Results highlight significant clinical improvements from baseline to follow-up for 32 patients who submitted follow-up data, including 28 patients who reported a minimum 1-point improvement in the overall condition score. CLINICAL RELEVANCE: These results suggest that autologous chondrocyte implantation may be an effective option for children and adolescents with large symptomatic chondral lesions of the distal femur.     

细胞移植技术修复关节软骨缺损的临床应用进展

关节软骨缺损在医学临床较为常见,由于关节软骨缺少血供,一旦损伤难于完全再生修复。由外伤、手术切除（如肿瘤）、感染、痛风和退变等引起的关节部位软骨缺损,常表现为顽固性疼痛、关节活动障碍,严重者可丧失关节功能,已成为导致肢体残废和劳动能力丧失的主要原因之一。据中国疾病预防与控制中心不完全统计,随着全民健身运动普及和社会老龄化等因素,因各种原因导致的软骨缺损的发病率逐年递增。采用细胞移植技术修复关节软骨缺损不同于一般的技术,它是试图再生关节软骨,而不是在修复区域形成纤维软骨,目前该技术已在国内外个别医院进行临床初步应用,呈不断完善发展的趋势。现就细胞移植治疗新技术的应用进行综述。     

Autologous chondrocyte transplantation for treatment of cartilage defects of the knee joint. Clinical results

Cartilage defects in the knee joint are common and have a bad tendency for healing due to the limited regeneration of hyaline cartilage. Surgeons have an ample choice of various operative treatment measures. Especially for the treatment of larger lesions first results of autologous chondrocyte transplantation (ACT) were published in 1994 [3]. Autologous chondrocytes are isolated from an arthoscopically harvested cartilage biopsy, cultured in vitro and implanted in the defect under a periostal flap in a second procedure. In an international multicenter study 1,051 patients treated with ACT between 6/95 and 12/98 were documented with follow-up examinations after 12 months (588 patients), 24 months (220 patients) and 36 months (40 patients). The majority of the defects (61.2%) were localized on the medial femoral condyle, measuring 4.6 cm2 and mostly described as grade III/IV lesions. The clinical evaluation was performed using a modified Cincinnati knee rating system independently for clinician and patient. Evaluations showed an increase from 3.35 to 6.25 after 24 months and from 3.10 to 6.77 in a scale from 1 (bad) to 10 (excellent). ACT favours defects of the femur with an improvement rate of 85%. Adverse events possibly related to ACT were described in 4.8% of the patients. Diagnostic second-look arthroscopies are included in the reoperation rate of 5.1%. The presented data indicate autologous chondrocyte transplantation as an effective and safe option for the treatment of large full thickness cartilage defects in the knee joint.     

The treatment of cartilage defects in the knee joint: microfracture, mosaicplasty, and autologous chondrocyte implantation

The efficacy of microfracture (MF), mosaicplasty (MO), and autologous chondrocyte implantation (ACI) techniques are still a matter of debate. This review aims to analyze comparative studies of these techniques, review the results of no treatment, and the natural history of untreated articular cartilage lesions. A PubMed search on the topic was performed. The most important (14) articles, as judged by the author, were selected for this review. There is limited evidence that any intervention significantly alters the natural history of these lesions and there is no evidence of significant difference between ACI and MF and MO. Paramount for successful surgical cartilage repair is a stable knee with a well-aligned lower limb. There is insufficient evidence at present to say that ACI is cost-effective, compared with MF or MO.