基质诱导的自体软骨细胞移植术修复膝关节软骨缺损1O例术后2年的随访

目的应用基质诱导的自体软骨细胞移植技术（MACI,Genzyme,America）对膝关节软骨损伤的患者进行治疗,通过对患者进行术后2年的随访分析,评价MACI治疗的安全性和有效性。方法从2004年至2008年11月,对10例患者实施MACI手术。患者平均年龄34.9岁（14～57岁）,缺损的平均面积（3.69±2.62）cm2/处（0.4～8cm2,n=20）。MACI技术是从患者非负重区取自体关节软骨,进行体外消化并分离出软骨细胞,培养扩增后接种在Ⅰ/Ⅲ型双层胶原膜上。移植前按缺损的部位修剪成相应形状,用生物蛋白胶将胶原膜粘贴在关节软骨缺损处。分别于术前1周、术后3个月、6个月、1年和2年使用KOOS评分问卷进行临床康复效果的评估并进行术后核磁共振的检测（MRI）。此外,术后对2例患者进行了3次关节镜检查和2次组织学检测。结果 10例患者术后均未发生并发症及与手术相关的不良事件。患者术后3个月KOOS评分显示疼痛明显改善（P〈0.05）;术后6个月KOOS评分显示：疼痛、症状、日常生活、运动及娱乐和生活质量5项均明显升高,5项评分间有统计学差异（P〈0.05）。术后1年和2年患者的情况得到了持续的改善（P〈0.05）。患者术后3个月的MRI显示软骨缺损部位得到大部分填充和修复;6个月移植软骨基本与周围软骨完全整合;1年后修复组织呈等信号,软骨下骨髓水肿消失;2年后大部分患者软骨修复组织信号与周围组织信号强度一致,软骨下骨无骨髓水肿。术后15个月和2年的组织学检查显示新生的软骨组织以透明软骨为主。MACI手术一般都能在2h内完成,术中出血量小于100ml。结论 MACI技术是修复关节软骨缺损安全、可靠和有效的治疗措施,具有操作简单、手术时间短和术中出血量少等特点。     

Autologous chondrocyte implantation for the treatment of retropatellar cartilage defects: clinical results referred to defect localisation

Introduction  Although autologous chondrocyte implantation (ACI) has become well established for the treatment of full-thickness cartilage defects of the knee joint, nevertheless clinical results of retropatellar lesions are still inferior compared to those of defects located on femoral condyles. We report the clinical results obtained in 70 patients treated with ACI for full-thickness defects of the patella, with special reference to defect location and size, age, body mass index and sports activity. Methods  At a follow-up of 38.4 months (range 14–64, follow-up rate 83.3%), patients’ subjective functional knee scores (IKDC, Lysholm) were analysed, as were the results of objective examination (according to ICRS). Results  Mean patient age at the time of surgery was 34.3 years (±10.1). The mean Lysholm score at the time of follow-up was 73.0 (±22.4) and the subjective IKDC score was 61.6 (±21.5); normal and nearly normal clinical results according to the objective criteria of the International Cartilage Research Society (ICRS) were achieved in 67.1% of the patients, while abnormal results were achieved in 20.0% of the patients and severely abnormal results, in 12.9%. While different surgical techniques did not seem to have any significant influence on the treatment results, both defect size and defect location within the patella were found to be significantly associated with clinical outcome. The corollaries to this are that larger cartilage lesions of the patella are associated with an inferior outcome (p = 0.007) and that cartilage defects located on the lateral patellar facet are correlated with a better clinical outcome than those located on the medial facet or those involving both facets (p = 0.017). Conclusion  This study demonstrates that within a group of patients treated with ACI for retropatellar cartilage lesion there are significant differences in clinical outcome, which are important and should be taken into account of when a decision has to be made on whether or not ACI is indicated.     

Autologous chondrocyte implantation versus matrix-induced autologous chondrocyte implantation for osteochondral defects of the knee: a prospective, randomised study

Autologous chondrocyte implantation (ACI) is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We have performed a prospective, randomised comparison of ACI-C and MACI for the treatment of symptomatic chondral defects of the knee in 91 patients, of whom 44 received ACI-C and 47 MACI grafts. Both treatments resulted in improvement of the clinical score after one year. The mean modified Cincinnati knee score increased by 17.6 in the ACI-C group and 19.6 in the MACI group (p = 0.32). Arthroscopic assessments performed after one year showed a good to excellent International Cartilage Repair Society score in 79.2% of ACI-C and 66.6% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43.9% of the ACI-C and 36.4% of the MACI grafts after one year. The rate of hypertrophy of the graft was 9% (4 of 44) in the ACI-C group and 6% (3 of 47) in the MACI group. The frequency of re-operation was 9% in each group. We conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI. While MACI is technically attractive, further long-term studies are required before the technique is widely adopted.     

Prospective clinical study of autologous chondrocyte implantation and correlation with MRI at three and 12 months

In order to determine the usefulness of MRI in assessing autologous chondrocyte implantation (ACI) the first 57 patients (81 chondral lesions) with a 12-month review were evaluated clinically and with specialised MRI at three and 12 months. Improvement 12 months after operation was found subjectively (37.6 to 51.9) and in knee function levels (from 85% International Cartilage Repair Society (ICRS) III/IV to 61% I/II). The International Knee Documentation Committee (IKDC) scores showed an initial deterioration at three months (56% IKDC A/B) but marked improvement at 12 months (88% A/B). The MRI at three months showed 82% of patients with at least 50% defect fill, 59% with a normal or nearly normal signal at repair sites, 71% with a mild or no effusion and 80% with a mild or no underlying bone-marrow oedema. These improved at 12 months to 93%, 93%, 94% and 91%, respectively. The overall MR score at 12 months suggested production of normal or nearly normal cartilage in 82%, corresponding to a subjective improvement in 81% of patients and 88% IKDC A/B scores. Second-look surgery and biopsies in 15 patients (22 lesions) showed a moderate correlation of MRI with visual scoring; 70% of biopsies showed hyaline and hyaline-like cartilage. Thus, MRI at 12 months is a reasonable non-invasive means of assessment of ACI.     

Third‐generation autologous chondrocyte implantation versus mosaicplasty for knee cartilage injury: 2‐year randomized trial

Numerous surgical techniques have been developed to treat osteochondral defects of the knee. A study reported encouraging outcomes of third‐generation autologous chondrocyte implantation achieved using the solid agarose‐alginate scaffold Cartipatch®. Whether this scaffold is better than conventional techniques remains unclear. This multicenter randomized controlled trial compared 2‐year functional outcomes (IKDC score) after Cartipatch® versus mosaicplasty in patients with isolated symptomatic femoral chondral defects (ICRS III and IV) measuring 2.5–7.5 cm². In addition, a histological evaluation based on the O'Driscoll score was performed after 2 years. We needed 76 patients to demonstrate an at least 10‐point subjective IKDC score difference with α = 5% and 90% power. During the enrolment period, we were able to include 55 patients, 30 of them were allocated at random to Cartipatch® and 25 to mosaicplasty. After 2 years, eight patients had been lost to follow‐up, six in the Cartipatch® group, and two in the mosaicplasty group. The baseline characteristics of the two groups were not significantly different. The mean IKDC score and score improvement after 2 years were respectively 73.7 ± 20.1 and 31.8 ± 20.8 with Cartipatch® and 81.5 ± 16.4 and 44.4 ± 15.2 with mosaicplasty. The 12.6‐point absolute difference in favor of mosaicplasty is statistically significant. Twelve adverse events were recorded in the Cartipatch® group against six in the mosaicplasty group. After 2 years, functional outcomes were significantly worse after Cartipatch® treatment compared to mosaicplasty for isolated focal osteochondral defects of the femur. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:658–665, 2016.     

Cartilage repair evolution in post-traumatic osteochondral lesions of the talus: from open field autologous chondrocyte to bone-marrow-derived cells transplantation

The aims of this study are to describe evolution in cartilage repair from open field autologous chondrocyte implantation to regeneration by arthroscopic bone-marrow-derived cells (BMDCs) “one step” technique; to present the results of a series of patients consecutively treated and to compare in detail the different techniques used in order to establish the advantages obtained with the evolution in cartilage regenerative methods.81 patients (mean age 30 ± 8 years) were evaluated in this study. Patient assessment included clinical AOFAS score, X-rays and MRI preoperatively and at different established follow-ups. All the lesions were >1.5 cm² and received open autologous chondrocyte implantation (10 cases), arthroscopic autologous chondrocyte implantation (46 cases), and “one step” arthroscopic repair by BMDC transplantation (25 cases). For arthroscopic repair techniques a hyaluronic acid membrane was used to support cells and specifically designed instrumentation was developed. Patients of all the three groups underwent a second arthroscopy with a bioptic cartilage harvest at 1 year follow-up.Mean AOFAS score before surgery was 57.1 ± 17.2 and 92.6 ± 10.5 (P < 0.0005) at mean 59.5 ± 26.5 months. A similar pattern of AOFAS improvement in results was found in the three different techniques. Histological evaluations highlighted collagen type II and proteoglycan expression.The cartilage repair techniques described were able to provide a repair tissue which closely approximates the characteristics of the naive hyaline cartilage. Evolution in surgical technique, new biomaterials and more recently the use of BMDCs permitted a marked reduction in procedure morbidity and costs up to a “one step” technique able to overcome all the drawbacks of previous repair techniques.     

A preliminary study comparing the use of allogenic chondrogenic pre‐differentiated and undifferentiated mesenchymal stem cells for the repair of full thickness articular cartilage defects in rabbits

Chondrogenic differentiated mesenchymal stem cells (CMSCs) have been shown to produce superior chondrogenic expression markers in vitro. However, the use of these cells in vivo has not been fully explored. In this study, in vivo assessment of cartilage repair potential between allogenic‐derived chondrogenic pre‐differentiated mesenchymal stem cells and undifferentiated MSCs (MSCs) were compared. Bilateral full thickness cartilage defects were created on the medial femoral condyles of 12 rabbits (n = 12). Rabbits were divided into two groups. In one group, the defects in the right knees were repaired using alginate encapsulated MSCs while in the second group, CMSCs were used. The animals were sacrificed and the repaired and control knees were assessed at 3 and 6 months after implantation. Quantitative analysis was performed by measuring the Glycosaminoglycans (GAGs)/total protein content. The mean Brittberg score was higher in the transplanted knees as compared to the untreated knee at 6 months (p < 0.05). Quantitative analysis of GAGs was consistent with these results. Histological and immunohistochemical analysis demonstrated hyaline‐like cartilage regeneration in the transplanted sites. Significant differences between the histological scores based on O'Driscoll histological grading were observed between contralateral knees at both 3 and 6 months (p < 0.05). No significant differences were observed between the Britberg, O'Driscoll scores, and GAGs/total protein content when comparing defect sites treated with MSC and CMSC (p > 0.05). This study demonstrates that the use of either MSC or CMSC produced superior healing when compared to cartilage defects that were untreated. However, both cells produced comparable treatment outcomes. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1336–1342, 2011     

Long-term clinical results and MRI changes after autologous chondrocyte implantation in the knee of young and active middle aged patients

Background

Autologous chondrocyte implantation (ACI) represents a valid surgical option for symptomatic full-thickness chondral lesions of the knee. Here we report long-term clinical and MRI results of first-generation ACI.

Materials and methods

Fifteen patients (mean age 21.3 years) underwent first-generation ACI for symptomatic chondral defects of the knee between 1997 and 2001. The mean size of the lesions was 5.08 cm² (range 2–9 cm²). Patients were evaluated using the International Knee Documentation Committee (IKDC) Knee Examination Form, the Tegner Activity Scale, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). High-resolution MRI was used to analyze the repair tissue with nine variables (the MOCART scoring system).

Results

The mean follow-up period was 148 months (range 125–177 months). ACI resulted in substantial improvements in all clinical outcome parameters, even as much as 12 years after implantation. A significant decrease in the MOCART score was recorded at final measurement. Reoperation was required in 2 patients; failure was caused by partial detachment of the graft in both cases.

Conclusion

Autologous chondrocyte implantation is an effective and durable solution for the treatment of large, full-thickness cartilage and osteochondral lesions, even in young and active middle-aged patients. High-resolution MRI is a useful and noninvasive method for evaluating the repaired tissue.

Level of evidence

IV.

     

Arthroscopic autologous chondrocyte implantation for the treatment of a chondral defect in the tibial plateau of the knee

The matrix-induced autologous chondrocyte implantation (MACI; Verigen, Leverküsen, Germany) is a tissue engineering technique for the treatment of deep chondral lesions. Cultured chondrocytes are seeded on a collagen membrane that can be implanted into the defect using exclusively fibrin glue. These features imply some surgical advantages with respect to the traditional ACI technique, such as the possibility of performing the procedure in articular sites, in which putting stitches for the periosteal patch is impossible. We report on the arthroscopic MACI technique for the treatment of a chondral defect of the knee. A 25-year-old man suffered persistent pain at the left knee after a violent direct trauma. Magnetic resonance imaging (MRI) and arthroscopic examination at the time of cartilage biopsy revealed a 2-cm² chondral lesion in the posterior portion of the lateral tibial plateau. The implantation procedure was performed through traditional arthroscopic portals, and the seeded membrane was fixed with fibrin glue, excluding water flow temporarily. Implant stability was verified intraoperatively, and filling of the defect was shown 12 months after surgery by MRI, which showed a hyaline-like cartilage signal. In this specific case, the arthroscopic approach allowed to achieve an optimal view of the lesion, without sacrificing any tendinous or ligamentous structure of the knee.     

Treatment of Deep Cartilage Defects of the Knee Using Autologous Chondrograft Transplantation and by Abrasive Techniques — A Randomized Controlled Study

Aim of the study: To compare outcomes of surgical treatment of deep cartilage defects of the knee in a group of patients treated by autologous chondrograft transplantation versus patients treated by abrasive techniques. Materials and methods: An original method of chondrograft preparation based on cultivated autologous chondrocytes in a three-dimensional carrier-fibrin glue (Tissucol, Baxter, Austria) has been described. Preclinical tests in human cadavres and porcine models have established the possibility of chondrograft use in humans.

Of the 50 patients included in the study, 25 patients (50%) underwent autologous chondrograft transplantation (group I) and 25 patients (50%) were treated using abrasive techniques according to Johnson (group II). These two groups were similar with respect to age, size of defect, depth and localization, and presence of concomitant knee injuries. The Lysholm knee and IKDC (International Knee Documentation Committee) subjective scores were used to evaluate the results.

Results: The preoperative value of the Lysholm knee score for patients in group I was 47.60 points; 5 months after surgery 77.20 points; and 12 months after surgery 86.48 points. The values for the Lysholm knee score for patients in group II preoperatively, 5 months postop, and 12 months postop were 52.60, 69.20, and 74.48 respectively. Results 12 months after surgery were significantly better in group I as compared to group II (p < 0.001). The preoperative value of the IKDC subjective score in group I was 41.28 points; 5 months after surgery 67.00 points; and 12 months after surgery 76.48 points. The values for the IKDC subjective score in group II preoperatively, 5 months postop, and 12 months postop were 45.00, 62.28, and 68.08 respectively. Results 12 months after surgery were significantly better in group I when compared to group II (p < 0.05).

Conclusions: The results obtained in this study have confirmed the better outcome in patients treated with autologous chondrograft transplantation. This original method was found to be just as effective as abrasive techniques. We recommend its use in clinical practice.     

Rekonstruktion von Gelenkknorpeldefekten mit einem Kollagen-I-Hydrogel

Study goals

The aim of the study was to evaluate the therapeutic benefit of CaReS?, a type I collagen hydrogel-based autologous chondrocyte implantation technique, for the treatment of osteochondral defects of the knee (Outerbridge grades III and IV) within a prospective multicenter study.

Material and methods

A total of 116?patients in 9 clinical centers were treated with CaReS between 2003 and 2008. The Cartilage Injury Evaluation Package 2000 of the International Cartilage Repair Society (ICRS) was employed for data acquisition and included the subjective International Knee Documentation Committee score (IKDC score), the pain level (visual analog scale, VAS), the physical and mental SF-36 score, the overall treatment satisfaction and the functional IKDC status of the indexed knee. Follow-up evaluation was performed 3, 6 and 12?months after surgery and annually thereafter.

Results

The mean defect size treated was 5.4?±?2.7?cm² with 30% of the cartilage defects being ?≤4?cm² and 70% ?≥4?cm². The mean follow-up period was 30.2?±?17.4?months (minimum 12?months and maximum 60?months). The mean IKDC score significantly improved from 42.4?±?13.8 preoperatively to 70.5?±?18.7 (p Conclusions The CaReS technique is a clinically effective and safe method for the reconstruction of isolated osteochondral defects of the knee joint and reveals promising clinical outcome up to 5?years after surgery. A longer follow-up period and larger patient cohorts are needed to evaluate the sustainability of CaReS treatment.     

Cartilage repair: A review of Stanmore experience in the treatment of osteochondral defects in the knee with various surgical techniques

Articular cartilage damage in the young adult knee, if left untreated, it may proceed to degenerative osteoarthritis and is a serious cause of disability and loss of function. Surgical cartilage repair of an osteochondral defect can give the patient significant relief from symptoms and preserve the functional life of the joint. Several techniques including bone marrow stimulation, cartilage tissue based therapy, cartilage cell seeded therapies and osteotomies have been described in the literature with varying results. Established techniques rely mainly on the formation of fibro-cartilage, which has been shown to degenerate over time due to shear forces. The implantation of autologous cultured chondrocytes into an osteochondral defect, may replace damaged cartilage with hyaline or hyaline-like cartilage. This clinical review assesses current surgical techniques and makes recommendations on the most appropriate method of cartilage repair when managing symptomatic osteochondral defects of the knee. We also discuss the experience with the technique of autologous chondrocyte implantation at our institution over the past 11 years.     

Autologous chondrocyte implantation at the knee using a bilayer collagen membrane with bone graft. A preliminary report

Autologous chondrocyte implantation (ACI) is a technique used for the treatment of symptomatic osteochondral defects of the knee. A variation of the original periosteum membrane technique is the matrix-induced autologous chondrocyte implantation (MACI) technique. The MACI membrane consists of a porcine type-I/III collagen bilayer seeded with chondrocytes. Osteochondral defects deeper than 8 to 10 mm usually require bone grafting either before or at the time of transplantation of cartilage. We have used a variation of Peterson's ACI-periosteum sandwich technique using two MACI membranes with bone graft which avoids periosteal harvesting. The procedure is suture-free and requires less operating time and surgical exposure. We performed this MACI-sandwich technique on eight patients, five of whom were assessed at six months and one year post-operatively using the modified Cincinnati knee, the Stanmore functional rating and the visual analogue pain scores. All patients improved within six months with further improvement at one year. The clinical outcome was good or excellent in four after six months and one year. No significant graft-associated complications were observed. Our early results of the MACI-sandwich technique are encouraging although larger medium-term studies are required before there is widespread adoption of the technique.     

Surgical management of large talar osteochondral defects using autologous chondrocyte implantation

Background

Talar osteochondral lesions (OLT) occur frequently in ankle sprains and fractures. We hypothesize that matrix-induced autologous chondrocyte implantation (MACI) will have a low reoperation rate and high patient satisfaction rate in treating OLT less than 2.5 cm².

自体软骨细胞联合Ⅰ型胶原治疗剥脱性膝骨软骨炎

目的探讨自体软骨细胞联合Ⅰ型胶原蛋白三维支架治疗膝关节剥脱性骨软骨炎的疗效。 方法选取近5年来在青岛市黄岛区中心医院采用自体软骨细胞联合Ⅰ型胶原蛋白三维支架治疗膝关节剥脱性骨软骨炎的患者12例,用单因素方差分析评估术前与术后6个月、12个月国际膝关节文献委员会(IKDC)膝关节评估表、Lysholm膝关节功能评分。术后12个月磁共振成像(MRI)评估软骨修复情况。 结果12例患者术后6个月、12个月的IKDC评分分别为(83.7±5.6)、(91.7±3.7),Lysholm评分分别为(87.5±5.2)、(93.6±2.1),均较术前IKDC评分(53.9±6.7)(F＝158.877)、Lysholm评分(59.1±7.2)(F＝104.258)明显改善(均为P<0.05);每2个时间点之间的IKDC评分、Lysholm评分,差异均具有统计学意义(P<0.05)。术后12个月MRI检查显示,所有患者的移植软骨恢复良好,均未出现移植物脱落或局部水肿。术后随访期内,所有患者均未出现膝关节感染。 结论自体软骨细胞联合Ⅰ型胶原蛋白三维支架能有效治疗膝关节剥脱性骨软骨炎。     

An evidence-based update on the management of articular cartilage defects in the hip

ObjectiveArticular cartilage defects in the hip joint pose a significant surgical challenge and remain one of the most important determinants of success following arthroscopic intervention of the hip. The aim of this literature review was to report on the best available evidence on the various treatment options utilised for articular cartilage defects in the hip.Material and methodsA comprehensive literature search was performed on PubMed from its inception to October 2021 using the following search strategy: ((hip) and (cartilage or chondral) and (repair or regeneration or restoration or implantation or chondroplasty or chondrogenic)). Two reviewers (KHSK, MG) independently reviewed titles and abstracts to identify articles for the final analysis. Articles were included if they were original research studies (randomised control trials, cohort studies, case-control studies, or comparative studies) on treatment of hip cartilage defects in humans reporting on a minimum of 5 patients. A total of 1172 articles were identified from the initial literature search. Following a thorough selection process, 35 articles were included in the final analysis to synthesise the evidence.ResultsDebridement, microfracture, autologous chondocyte implanatation (ACI) and matrix-induced ACI (MACI) are shown to have good short-to medium-term results. Injectable ACI and MACI have been developed to enable these procedures to be performed via arthroscopic surgery to reduce the post-operative morbidity associated with surgery with promising early results. Large cartilage defects which involved the sub-chondral bone may need the use of osteochondral grafts either autograft or allograft. Newer biological solutions have been developed to potentially deliver a single-stage procedure for hip cartilage injuries but longer-term results are still awaited.ConclusionAccurate identification of the extent of the injury helps stratify the defect and plan appropriate treatment. Several surgical techniques have shown good short to medium-term outcomes with ACI, AMIC, mosaicplasty and microfracture. Recent advances have enabled the use of injectable MACI and bioscaffolds which show promising results but in the shorter term. However, one needs to be mindful of the techniques which can be used in their surgical setting with the available resources. In order to thoroughly evaluate the benefits of the different surgical techniques for hip cartilage defects, large scale prospective multi-centre studies are necessary. Perhaps inclusion of such procedures in registries may also yield meaningful and pragmatic results.     

The present state of treatments for articular cartilage defects in the knee

INTRODUCTION

Chondral and osteochondral lesions of the knee are notoriously difficult to treat due to the poor healing capacity of articular cartilage and the hostile environment of moving joints, ultimately causing disabling pain and early osteoarthritis. There are many different reconstructive techniques used currently but few are proven to be of value. However, some have been shown to produce a better repair with hyaline-like cartilage rather than fibrocartilage.

METHODS

A systematic search of all available online databases including PubMed, MEDLINE® and Embase™ was undertaken using several keywords. All the multiple treatment options and methods available were considered. These were summarised and the evidence for and against them was scrutinised.

RESULTS

A total of 460 articles were identified after cross-referencing the database searches using the keywords. These revealed that autologous and matrix assisted chondrocyte implantation demonstrated both ‘good to excellent’ histological results and significant improvement in clinical outcomes.

CONCLUSIONS

Autologous and matrix assisted chondrocyte implantation have been shown to treat symptomatic lesions successfully with significant histological and clinical improvement. There is, however, still a need for further randomised clinical trials, perfecting the type of scaffold and the use of adjuncts such as growth factors. A list of recommendations for treatment and the potential future trends of managing these lesions are given.     

Autologous Chondrocyte Implantation for Talar Osteochondral Lesions: Comparison Between 5-Year Follow-Up Magnetic Resonance Imaging Findings and 7-Year Follow-Up Clinical Results

Autologous chondrocyte implantation (ACI) is an established surgical procedure that has provided satisfactory results. The aim of the present study was to correlate the clinical outcomes of a series of 20 patients treated by ACI at a 7-year follow-up examination with the magnetic resonance imaging (MRI) T2-mapping 5-year follow-up findings. We evaluated 20 patients using the American Orthopaedic Foot and Ankle Society (AOFAS) score preoperatively and the established follow-up protocol until 87.2 ± 14.5 months. MRI T2-mapping sequences were acquired at the 5-year follow-up examination. At the MRI examination (60 ± 12 months), the mean AOFAS score improved from 58.7 ± 15.7 to 83.9 ± 18.4. At the final follow-up examination at 87.2 ± 14.5 months, the AOFAS score was 90.9 ± 12.7 (p = .0005). Those patients who experienced an improvement between 5 and 7 years after surgery had a significant greater percentage of T2-map value of 35 to 45 ms (hyaline cartilage) compared with those patients who did not improve (p = .038). MRI T2 mapping was shown to be a valuable tool capable of predicting reproducible clinical outcomes after ACI even 7 years after surgery. The quality of the regenerated tissue and the degree of defect filling became statistically significant to the clinical results at the final follow-up examination.     

Classification of graft hypertrophy after autologous chondrocyte implantation of full-thickness chondral defects in the knee

OBJECTIVE: Graft hypertrophy is a major complication seen in autologous chondrocyte implantation (ACI) with a periosteal flap. We present the first magnetic resonance imaging (MRI) classification for periosteal hypertrophy including a grading of clinical symptoms and the surgical consequences. METHODS: One hundred and two patients with isolated chondral defects underwent an ACI covered with periosteum and were evaluated preoperatively, 6, 18 and 36 months after surgery. Exclusion criteria were meniscal pathologies, axial malpositioning and ligament instabilities. Baseline clinical scores were compared with follow-up data by paired Wilcoxon-tests for the modified Cincinnati knee, the ICRS (International Cartilage Repair Society) and a new MRI score including the parameters defect filling, subchondral edema, effusion, cartilage signal and graft hypertrophy. Hypertrophic changes were graded from 1 (minimal) to 4 (severe). RESULTS: All scores showed significant improvement (P<0.001) over the entire study period. Patients with femoral lesions had significantly better results than patients with patella lesions after 18 and 36 months postoperative (P<0.03). Periosteal hypertrophy occurred in 28% of all patients. Fifty percent of all patella implants developed hypertrophic changes. No patient with grade 1, and all patients with grade 4 hypertrophy had to undergo revision surgery. The Pearson correlation between graft hypertrophy and ICRS score was 0.78 after 6 months, and 0.69 after 36 months (P<0.01). Inclusion of graft hypertrophy in the MRI score improves the correlation to clinical scores from 0.6 to 0.69. CONCLUSIONS: Grading graft hypertrophy helps to identify patients needing an early shaving of the graft. Its integration into an MRI score improves correlation with clinical scores. Re-operation depends on the grade of hypertrophy and clinical symptoms.     

One intra‐articular injection of hyaluronan prevents cell death and improves cell metabolism in a model of injured articular cartilage in the rabbit

The purpose of this study was to determine the effect of one intra‐articular injection of hyaluronan on chondrocyte death and metabolism in injured cartilage. Twenty‐three 6‐month‐old rabbits received partial‐thickness articular cartilage defects created on each medial femoral condyle. In order to examine the effect on articular cartilage surrounding iatrogenic cartilage lesions, which can occur during arthroscopic procedures, Study 1 was performed: in 14 rabbits both knees were immediately rinsed with 0.9% NaCl. Experimental knees were treated with hyaluronan. Six rabbits were sacrificed at 2 days; eight rabbits 3 months postoperatively. Histomorphometric analysis was used for studying cell death in cartilage next to the defect. In order to examine the effect on longer lasting lesions, more reflecting the clinical situation, Study 2 was performed: after 6 months knee joints of nine rabbits were (i) irrigated with 0.9% NaCl, (ii) treated with hyaluronan after irrigation with 0.9% NaCl, or (iii) sham‐treated. After 7 days patellas were used to study the chondrocyte metabolism by measuring the [³⁵S]sulfate incorporation. Study 1: Two days postoperatively, in hyaluronan‐treated cartilage the percentage of dead cells was 6.7%, which was significantly lower compared to 16.2% in saline‐treated cartilage. After 3 months the percentages of dead cells in both groups were statistically similar. Study 2: Hyaluronan treatment resulted in significantly higher [³⁵S]sulfate incorporation compared to knees irrigated with 0.9% NaCl. These results suggest a potential role for hyaluronan in preventing cell death following articular cartilage injury. One injection of hyaluronan improved cartilage metabolism in knees with 6‐month‐old cartilage defects. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:624–630, 2008