[Osteochondral transplantation versus autogenous chondrocyte transplantation. A prospective comparative clinical study]

Autologous chondrocyte implantation in the knee: systematic review and economic evaluation

BACKGROUND

The surfaces of the bones in the knee are covered with articular cartilage, a rubber-like substance that is very smooth, allowing frictionless movement in the joint and acting as a shock absorber. The cells that form the cartilage are called chondrocytes. Natural cartilage is called hyaline cartilage. Articular cartilage has very little capacity for self-repair, so damage may be permanent. Various methods have been used to try to repair cartilage. Autologous chondrocyte implantation (ACI) involves laboratory culture of cartilage-producing cells from the knee and then implanting them into the chondral defect.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of ACI in chondral defects in the knee, compared with microfracture (MF).

DATA SOURCES

A broad search was done in MEDLINE, EMBASE, The Cochrane Library, NHS Economic Evaluation Database and Web of Science, for studies published since the last Health Technology Assessment review.

REVIEW METHODS

Systematic review of recent reviews, trials, long-term observational studies and economic evaluations of the use of ACI and MF for repairing symptomatic articular cartilage defects of the knee. A new economic model was constructed. Submissions from two manufacturers and the ACTIVE (Autologous Chondrocyte Transplantation/Implantation Versus Existing Treatment) trial group were reviewed. Survival analysis was based on long-term observational studies.

RESULTS

Four randomised controlled trials (RCTs) published since the last appraisal provided evidence on the efficacy of ACI. The SUMMIT (Superiority of Matrix-induced autologous chondrocyte implant versus Microfracture for Treatment of symptomatic articular cartilage defects) trial compared matrix-applied chondrocyte implantation (MACI^®) against MF. The TIG/ACT/01/2000 (TIG/ACT) trial compared ACI with characterised chondrocytes against MF. The ACTIVE trial compared several forms of ACI against standard treatments, mainly MF. In the SUMMIT trial, improvements in knee injury and osteoarthritis outcome scores (KOOSs), and the proportion of responders, were greater in the MACI group than in the MF group. In the TIG/ACT trial there was improvement in the KOOS at 60 months, but no difference between ACI and MF overall. Patients with onset of symptoms < 3 years' duration did better with ACI. Results from ACTIVE have not yet been published. Survival analysis suggests that long-term results are better with ACI than with MF. Economic modelling suggested that ACI was cost-effective compared with MF across a range of scenarios.

LIMITATIONS

The main limitation is the lack of RCT data beyond 5 years of follow-up. A second is that the techniques of ACI are evolving, so long-term data come from trials using forms of ACI that are now superseded. In the modelling, we therefore assumed that durability of cartilage repair as seen in studies of older forms of ACI could be applied in modelling of newer forms. A third is that the high list prices of chondrocytes are reduced by confidential discounting. The main research needs are for longer-term follow-up and for trials of the next generation of ACI.

CONCLUSIONS

The evidence base for ACI has improved since the last appraisal by the National Institute for Health and Care Excellence. In most analyses, the incremental cost-effectiveness ratios for ACI compared with MF appear to be within a range usually considered acceptable. Research is needed into long-term results of new forms of ACI.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013083.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The comparison between the different generations of autologous chondrocyte implantation with other treatment modalities: a systematic review of clinical trials

PURPOSE

This paper aims to review the current evidence for autologous chondrocyte implantation (ACI) generations relative to other treatment modalities, different cell delivery methods and different cell source application.

METHODS

Literature search was performed to identify all level I and II studies reporting the clinical and structural outcome of any ACI generation in human knees using the following medical electronic databases: PubMed, EMBASE, Cochrane Library, CINAHL, SPORTDiscus and NICE healthcare database. The level of evidence, sample size calculation and risk of bias were determined for all included studies to enable quality assessment.

RESULTS

Twenty studies were included in the analysis, reporting on a total of 1094 patients. Of the 20 studies, 13 compared ACI with other treatment modalities, seven compared different ACI cell delivery methods, and one compared different cell source for implantation. Studies included were heterogeneous in baseline design, preventing meta-analysis. Data showed a trend towards similar outcomes when comparing ACI generations with other repair techniques and when comparing different cell delivery methods and cell source selection. Majority of the studies (80 %) were level II evidence, and overall the quality of studies can be rated as average to low, with the absence of power analysis in 65 % studies.

CONCLUSION

At present, there are insufficient data to conclude any superiority of ACI techniques. Considering its two-stage operation and cost, it may be appropriate to reserve ACI for patients with larger defects or those who have had inadequate response to other repair procedures until hard evidence enables specific clinical recommendations be made.

LEVEL OF EVIDENCE

II.

The Periosteal Autografts Transplantation for Cartilage Defects of the Hip in Older Children With Developmental Dysplasia as an Adjunctive Procedure

Cartilage lesions are at a high prevalence in dysplastic hips and may relate to arthritic changes and hip joint dysfunction. To date, the effectiveness of repair of articular cartilage defects in the dysplastic hips has not yet been thoroughly evaluated. Here we retrospectively reviewed the effects of acetabuloplasty procedures with/without concomitant autologous tibial periosteal transplantation (ATPT) for articular cartilage defects of the hip in older children with developmental dysplasia of the hip (DDH).Older DDH children with focal cartilage defects of the acetabular or femoral cartilage or both in the hip joint were treated by acetabuloplasty procedures with (Group I) or without (Group II) concomitant ATPT to evaluate the improvements in range of motion (ROM), pain relief of hip, walking tolerability (WL), radiologic evaluations, and outcomes in the long-term follow-up.More satisfactory functional outcome is readily achieved among patients treated with combined acetabuloplasty and ATPT, evidenced by marked pain relief and improved ROM and WL. The latest favorable radiologic evaluation was 70.6% in Group I and 60.0% in Group II, respectively. More hips exhibited congruency between the femoral head and the shell, with less deformity of femoral head and acetabulum or narrowed joint space in Group I. Few major complications were recorded in Group I.Application of periosteal autograft for repair of cartilage defects within the hip joint might be an effective adjunctive treatment for acetabuloplasty in preventing stiffness, reducing pain, and improving ROM and outcomes in hip rehabilitation in the long-term follow-up in older children with DDH.

Initial boost release of transforming growth factor-β3 and chondrogenesis by freeze-dried bioactive polymer scaffolds

In cartilage regeneration, bio-activated implants are used in stem and progenitor cell-based microfracture cartilage repair procedures. Our aim was to analyze the chondrogenic potential of freeze-dried resorbable polymer-based polyglycolic acid (PGA) scaffolds bio-activated with transforming growth factor-β3 (TGFB3) on human subchondral mesenchymal progenitor cells known from microfracture. Progenitor cells derived from femur heads were cultured in the presence of freeze-dried TGFB3 in high-density pellet culture and in freeze-dried TGFB3-PGA scaffolds for chondrogenic differentiation. Progenitor cell cultures in PGA scaffolds as well as pellet cultures with and without continuous application of TGFB3 served as controls. Release studies showed that freeze-dried TGFB3-PGA scaffolds facilitate a rapid, initial boost-like release of 71.5% of TGFB3 in the first 10 h. Gene expression analysis and histology showed induction of typical chondrogenic markers like type II collagen and formation of cartilaginous tissue in TGFB3-PGA scaffolds seeded with subchondral progenitor cells and in pellet cultures stimulated with freeze-dried TGFB3. Chondrogenic differentiation in freeze-dried TGFB3-PGA scaffolds was comparable to cultures receiving TGFB3 continuously, while non-stimulated controls did not show chondrogenesis during prolonged culture for 14 days. These results suggest that bio-activated, freeze-dried TGFB3-PGA scaffolds have chondrogenic potential and are a promising tool for stem cell-mediated cartilage regeneration.

Feasibility of arthroscopic 3-dimensional, purely autologous chondrocyte transplantation for chondral defects of the hip: a case series

INTRODUCTION

The purpose of this retrospective study was to describe technical aspects of arthroscopic, purely autologous chondrocyte transplantation of the hip and to report short-term data of the postoperative outcome in a consecutive series of patients.

MATERIALS AND METHODS

We retrospectively analyzed six patients with a full-thickness chondral defect of the hip joint. The defect was treated with an arthroscopically applicable 3-dimensional purely autologous chondrocyte transplant product (chondrosphere(®); co.don(®) AG, Berlin, Germany) in a two-step surgical procedure. Patient-administered scores were assessed at baseline (day before transplantation) and at 6 weeks, 3, 6 and 12 months.

RESULTS

Six out of six initially included patients (five males, one female) with a median age of 32.5 years and an average defect size of 3.5 cm(2) were available for follow-up after a mean of 11.2 months. Five acetabular and one femoral defect were treated. An overall statistically significant improvement was observed for all assessment scores (NHS, mHHS and SF 36).

CONCLUSION

In this study, we displayed the feasibility and technical aspects of arthroscopic matrix-associated, purely autologous chondrocyte transplantation as a treatment option for full-thickness cartilage defects of the hip. The patient-administered assessment scores demonstrated an increase in activity level and quality of life after a 1-year follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Karyotyping of human chondrocytes in scaffold-assisted cartilage tissue engineering

Scaffold-assisted autologous chondrocyte implantation (ACI) is an effective clinical procedure for cartilage repair. The aim of our study was to evaluate the chromosomal stability of human chondrocytes subjected to typical cell culture procedures needed for regenerative approaches in polymer-scaffold-assisted cartilage repair. Chondrocytes derived from post mortem donors and from donors scheduled for ACI were expanded, cryopreserved and re-arranged in polyglycolic acid (PGA)-fibrin scaffolds for tissue culture. Chondrocyte redifferentiation was analyzed by electron microscopy, histology and gene expression analysis. Karyotyping was performed using GTG banding and fluorescence in situ hybridization on a single cell basis. Chondrocytes showed de- and redifferentiation accompanied by the formation of extracellular matrix and induction of typical chondrocyte marker genes like type II collagen in PGA-fibrin scaffolds. Post mortem chondrocytes showed up to 1.7% structural and high numbers of numerical (up to 26.7%) chromosomal aberrations, while chondrocytes from living donors scheduled for ACI showed up to 1.8% structural and up to 1.3% numerical alterations. Cytogenetically, cell culture procedures and PGA-fibrin scaffolds did not significantly alter chromosomal integrity of the chondrocyte genome. Human chondrocytes derived from living donors subjected to regenerative medicine cell culture procedures like cell expansion, cryopreservation and culture in resorbable polymer-based scaffolds show normal chromosomal integrity and normal karyotypes.

State of the art and future perspectives of articular cartilage regeneration: a focus on adipose-derived stem cells and platelet-derived products

Trauma, malposition and age-related degeneration of articular cartilage often result in severe lesions that do not heal spontaneously. Many efforts over the last centuries have been undertaken to support cartilage healing, with approaches ranging from symptomatic treatment to structural cartilage regeneration. Microfracture and matrix-associated autologous chondrocyte transplantation (MACT) can be regarded as one of the most effective techniques available today to treat traumatic cartilage defects. Research is focused on the development of new biomaterials, which are intended to provide optimized physical and biochemical conditions for cell proliferation and cartilage synthesis. New attempts have also been undertaken to replace chondrocytes with cells that are more easily available and cause less donor site morbidity, e.g. adipose derived stem cells (ASC). The number of in vitro studies on adult stem cells has rapidly increased during the last decade, indicating that many variables have yet to be optimized to direct stem cells towards the desired lineage. The present review gives an overview of the difficulties of cartilage repair and current cartilage repair techniques. Moreover, it reviews new fields of cartilage tissue engineering, including stem cells, co-cultures and platelet-rich plasma (PRP).

Autologous chondrocyte implantation for full thickness articular cartilage defects of the knee

BACKGROUND

Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop. An alternative is autologous chondrocyte implantation (ACI), the surgical implantation of healthy cartilage cells into the damaged areas.

OBJECTIVES

To determine the efficacy and safety of ACI in people with full thickness articular cartilage defects of the knee.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (3 December 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 4), MEDLINE (1950 to November Week 3 2008), EMBASE (1980 to Week 48 2008), SPORTDiscus (3 December 2008), the WHO International Clinical Trials Registry Platform (4 December 2008), and Current Controlled Trials (3 December 2008).

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella.

DATA COLLECTION AND ANALYSIS

Review authors selected studies for inclusion independently. We assessed risk of bias based on adequacy of the randomisation and allocation concealment process, potential for selection bias after allocation and level of masking. We did not pool data due to clinical and methodological heterogeneity.

MAIN RESULTS

Six heterogeneous trials were identified with 431 participants. Methodological flaws of the included trials included incomplete follow-up and inadequate reporting of outcomes. Three trials compared ACI versus mosaicplasty. One reported statistically significant results in favour of ACI at one year in the numbers of people with 'good' or 'excellent' functional results. Conversely, another trial found significant improvement for the mosaicplasty group when assessed using one functional scoring system at two years, but no statistically significant differences based on two other scoring systems. A third trial found no difference between ACI and mosaicplasty, 10 months on average after the surgery.There was no statistically significant difference in functional outcomes at two years in single trials comparing ACI with microfracture or characterised chondrocyte implantation versus microfracture. The results of the sixth trial comparing matrix-guided ACI versus microfracture were undermined by the severe loss to follow-up.

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw conclusions on the use of ACI for treating full thickness articular cartilage defects in the knee. Further good quality randomised controlled trials with long-term functional outcomes are required.

Autologous chondrocyte implantation versus ACI using 3D-bioresorbable graft for the treatment of large full-thickness cartilage lesions of the knee

BACKGROUND

In autologous chondrocyte implantation (ACI), the periosteum patch which is sutured over the cartilage defect has been identified as a major source of complications such as periosteal hypertrophy. In the present retrospective study, we compared midterm results of first-generation ACI with a periosteal patch to second generation ACI using a biodegradable collagen fleece (BioSeed-C) in 82 patients suffering from chronic posttraumatic and degenerative cartilage lesions of the knee.

METHODS

Clinical outcome was assessed in 42 patients of group 1 and in 40 patients of group 2 before implantation of the autologous chondrocytes and at a minimum follow-up of 2 years using the ICRS score, the modified Cincinnati score and the Lysholm score.

RESULTS

Although patients treated with BioSeed-C had more previous surgical procedures on their respective knees, highly significant improvements (P < 0.001) were assessed in both groups at comparable outcome levels: the ICRS score improved from grade D (poor) preoperatively to grade C (fair); the modified Cincinnati knee score from 3.26 to 6.4 (group 1) and 3.3 and 6.88 (group 2). Lysholm score improved from 33 to 70 points (group 1) and from 47 to 78 points (group 2), respectively. Revision surgery was due to symptomatic periosteal hypertrophy (n = 4), graft failure (n = 3), plica syndrome (n = 2) synovectomy (n = 1) (group 1); and graft failure (n = 2), debridement (n = 1), synovectomy (n = 2) (group 2).

CONCLUSION

These results suggest that BioSeed-C is an equally effective treatment option for focal degenerative chondral lesions of the knee in this challenging and complex patient profile.

Effectiveness of autologous chondrocyte implantation in cartilage repair of the knee: a systematic review of controlled trials

OBJECTIVE

The relative differences in effectiveness of subchondral stimulation, osteochondral grafts, and autologous chondrocyte implantation (ACI) are still unclear. It is the objective of this study to systematically review the literature on ACI compared to other treatments by clinical outcome and the quality of the repair tissue, including an assessment of the validity of these findings.

METHOD

The online databases PubMed, EMBASE, Cochrane Controlled Trial Register, CENTRAL, CINAHL, and BioMed were searched. Controlled trials comparing ACI with other methods of cartilage repair or placebo were included. Data on clinical outcome and the quality of the repair tissue was abstracted in duplicate. Study validity was assessed by individual components (randomization, blinded outcome assessment, sample size, attrition, percentage biopsies).

RESULTS

Nine studies were included. The internal validity of most of these studies was poor. Studies comparing ACI with subchondral stimulation have a higher quality and show no differences in clinical outcomes, but suggest better results in tissue quality. The high quality evidence comparing ACI with osteochondral grafts shows better clinical outcomes and higher tissue quality after ACI.

CONCLUSION

Among the included studies there is much inconsistency in methodological quality and findings. Regardless of these problems, the absolute differences between groups are fairly small, thus raising questions about their clinical importance. Future studies will be needed to answer the question of benefits of ACI compared to other treatments, and could profit from addressing and avoiding the problems seen in this group. Finally conclusions concerning long-term effects are still difficult.

Semi-degradable scaffold for articular cartilage replacement

Existing technologies have not met the challenge of designing a construct for the repair of focal cartilage defects such that it mimics the mechanical properties of and can integrate with native cartilage. Herein we describe a novel construct consisting of a non-degradable poly-vinyl alcohol (PVA) scaffold to provide long-term mechanical stability, interconnected pores to allow for the infiltration of chondrocytes, and poly-lactic glycolic acid (PLGA) microspheres for the incorporation of growth factors to enhance cellular migration. The objective of this study was to characterize the morphological features and mechanical properties of our porous PVA-PLGA construct as a function of PLGA content. Varying the PLGA content was found to have a significant effect on the morphological features of the construct. As PLGA content increased from 10% to 75%, samples exhibited a 6-fold increase in average percentage porosity, an increase in average microsphere diameter from 8 to 34 microm and an increase in average pore diameter from 29 to 111 microm. The effect of PLGA content on aggregate modulus and permeability was less profound. Our findings suggest that that morphology of the construct can be tailored to optimize cellular infiltration and the dynamic mechanical response. The experiments herein presented were conducted at the Hospital for Special Surgery.

Cartilage T2 assessment at 3-T MR imaging: in vivo differentiation of normal hyaline cartilage from reparative tissue after two cartilage repair procedures--initial experience

PURPOSE

To prospectively compare cartilage T2 values after microfracture therapy (MFX) and matrix-associated autologous chondrocyte transplantation (MACT) repair procedures.

MATERIALS AND METHODS

The study had institutional review board approval by the ethics committee of the Medical University of Vienna; informed consent was obtained. Twenty patients who underwent MFX or MACT (10 in each group) were enrolled. For comparability, patients of each group were matched by mean age (MFX, 40.0 years +/- 15.4 [standard deviation]; MACT, 41.0 years +/- 8.9) and postoperative interval (MFX, 28.6 months +/- 5.2; MACT, 27.4 months +/- 13.1). Magnetic resonance (MR) imaging was performed with a 3-T MR imager, and T2 maps were calculated from a multiecho spin-echo measurement. Global, as well as zonal, quantitative T2 values were calculated within the cartilage repair area and within cartilage sites determined to be morphologically normal articular cartilage. Additionally, with consideration of the zonal organization, global regions of interest were subdivided into deep and superficial areas. Differences between cartilage sites and groups were calculated by using a three-way analysis of variance.

RESULTS

Quantitative T2 assessment of normal native hyaline cartilage showed similar results for all patients and a significant trend of increasing T2 values from deep to superficial zones (P < .05). In cartilage repair areas after MFX, global mean T2 was significantly reduced (P < .05), whereas after MACT, mean T2 was not reduced (P > or = .05). For zonal variation, repair tissue after MFX showed no significant trend between different depths (P > or = .05), in contrast to repair tissue after MACT, in which a significant increase from deep to superficial zones (P < .05) could be observed.

CONCLUSION

Quantitative T2 mapping seems to reflect differences in repair tissues formed after two surgical cartilage repair procedures. (c) RSNA, 2008.

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.

Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results

Autologous chondrocyte implantation (ACI) is an effective clinical procedure for the regeneration of articular cartilage defects. BioSeed^®-C is a second-generation ACI tissue engineering cartilage graft that is based on autologous chondrocytes embedded in a three-dimensional bioresorbable two-component gel-polymer scaffold. In the present prospective study, we evaluated the short-term to mid-term efficacy of BioSeed-C for the arthrotomic and arthroscopic treatment of posttraumatic and degenerative cartilage defects in a group of patients suffering from chronic posttraumatic and/or degenerative cartilage lesions of the knee. Clinical outcome was assessed in 40 patients with a 2-year clinical follow-up before implantation and at 3, 6, 12, and 24 months after implantation by using the modified Cincinnati Knee Rating System, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score, and the current health assessment form (SF-36) of the International Knee Documentation Committee, as well as histological analysis of second-look biopsies. Significant improvement (p < 0.05) in the evaluated scores was observed at 1 and/or 2 years after implantation of BioSeed-C, and histological staining of the biopsies showed good integration of the graft and formation of a cartilaginous repair tissue. The Knee injury and Osteoarthritis Outcome Score showed significant improvement in the subclasses pain, other symptoms, and knee-related quality of life 2 years after implantation of BioSeed-C in focal osteoarthritic defects. The results suggest that implanting BioSeed-C is an effective treatment option for the regeneration of posttraumatic and/or osteoarthritic defects of the knee.

Repair of osteochondral defects in the knee by resorbable bioimplants in a rabbit model

BACKGROUND

The intrinsic healing capacity of articular cartilage remains poor, despite various attempts that have been undertaken to treat cartilage defects. This study describes the experimental use of a double-layer bioimplant consisting of a bone-substitute layer and a cartilage-substitute layer.

ANIMALS AND METHODS

In group A, 12 implants were placed into osteochondral defects of the load-bearing area of rabbit femoral condyles. In group B, 12 implantations were done in the same manner, with a separating membrane consisting of cement between both layers to investigate ingrowth of mesenchymal stem cells from the subchondral marrow space. Group C, with 12 similar defects but without treatment, served as control. Investigations by microscopy and immunohistochemistry were done after 12 weeks.

RESULTS

All bioimplants showed coverage of the defect with a regeneration tissue that contained cartilage-like regions. Implants with a cement layer showed less cartilage and more fibrous tissue. The bioimplant group showed more cartilage-like regeneration tissue than the control groups, which only showed incomplete fibrous filling of the defects. Results from the second group supported the hypothesis that the subchondral space must be opened for adequate regeneration. Additional examinations were done using an established semiquantitative score. The bioimplant group showed a significant improvement in results compared to the group with the separating layer and the control group.

INTERPRETATION

Our findings indicate that cartilage repair by resorbable bioimplants seems to be a promising new approach, especially if mesenchymal stem cells are present and can differentiate under mechanical load.

Autologous cartilage implantation for full thickness articular cartilage defects of the knee

BACKGROUND

Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop, resulting in the need for a total knee replacement. An alternative is the surgical implantation of healthy cartilage cells into damaged areas (autologous cartilage implantation).

OBJECTIVES

To determine the effectiveness of autologous cartilage implantation (ACI) in people with full thickness articular cartilage defects of the knee.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (15 December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to December 2005), CINAHL (1982 to December Week 2, 2004), EMBASE (1988 to 2005 Week 50), SPORTDiscus (1830 to January 2005) and the National Research Register Issue 3, 2005.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella.

DATA COLLECTION AND ANALYSIS

Two review authors selected studies for inclusion independently. We assessed study quality based on adequacy of the randomisation process, adequacy of the allocation concealment process, potential for selection bias after allocation and level of masking. Data was not pooled due to clinical and methodological heterogeneity in the studies.

MAIN RESULTS

We included four randomised controlled trials (266 participants). One trial of ACI versus mosaicplasty reported statistically significant results for ACI at one year, but only in a post-hoc subgroup analysis of participants with medial condylar defects; 88% had excellent or good results with ACI versus 69% with mosaicplasty. A second trial of ACI versus mosaicplasty found no statistically significant difference in clinical outcomes at two years. There was no statistically significant difference in outcomes at two years in a trial comparing ACI with microfracture. In addition, one trial of matrix-guided ACI versus microfracture did not contain enough long-term results to reach definitive conclusions.

AUTHORS' CONCLUSIONS

The use of ACI and other chondral resurfacing techniques is becoming increasingly widespread. However, there is at present no evidence of significant difference between ACI and other interventions. Additional good quality randomised controlled trials with long-term functional outcomes are required.

Engineered mesenchymal stem cells for cartilage repair

Healthy cartilage is a highly robust tissue, and is resilient against the stringent mechanical and biological contraints imposed upon it. Cartilage defects are common features of joint diseases, but current treatments can rarely restore the full function of native cartilage. Recent studies have provided new perspectives for cartilage engineering using mesenchymal stem cells (MSCs). However, the sequential events occurring during chondrogenesis must be fully understood before we are able to reproduce faithfully the complex molecular events that lead to MSC differentiation and long-term maintenance of cartilage characteristics. Here, we focus on the potential of MSCs to repair cartilage with an emphasis on the factors that are known to be required in inducing chondrogenesis.

Transgene-activated mesenchymal cells for articular cartilage repair: a comparison of primary bone marrow-, perichondrium/periosteum- and fat-derived cells

BACKGROUND

Adult primary mesenchymal cells of different origin which can be obtained with minor donor site morbidity are considered for articular cartilage repair. This study aims at a comparison of their chondrogenic potential.

METHODS

Mesenchymal cells were isolated from perichondrium/periosteum, bone marrow or fat of adult rats and found to be positive for the stem-cell-related antigens Sca-1, c-Kit, CD10, CD13 and CD90 by reverse transcription polymerase chain reaction (RT-PCR). Chondrogenic differentiation was induced by applying recombinant bone morphogenetic protein-2 (BMP-2) or adenoviral vectors carrying BMP-2 cDNA, followed by micromass culture. The stimulated cells were characterized by RT-PCR, cell proliferation and apoptosis assays. Expression of aggrecan, collagen type I, II, IX and X and alkaline phosphatase genes was analyzed by RT-PCR, immunofluorescence and immunohistochemistry in comparison with unstimulated control cells. Adenovirally stimulated cells were transplanted into mechanically generated partial-thickness cartilage lesions in the patellar groove of the rat femur. Quality and integration of the repair tissues were assessed by histochemical and immunohistochemical methods.

RESULTS

Stimulation with BMP-2 or AdBMP-2 led to an up-regulation of cartilage-specific gene expression in all three cell populations studied, most rapidly and prominently in the perichondrial/periosteal cells, which showed a 3200-fold increase of type II collagen mRNA and reached the highest absolute levels of type II and IX collagen transcripts after stimulation. Similar results were obtained for the bone marrow stromal cells (BMSC), while the respective transcript levels in fat stromal cells declined after an initial more than 30-fold elevation. Following transplantation in vivo, AdBMP-2-infected perichondrial/periosteal cells produced a proteoglycan-rich, type II collagen-positive matrix with only faint staining for type I collagen. The repair tissue originating from AdBMP-2-infected BMSC showed less intense type II collagen staining, but a relatively proteoglycan-rich matrix, weakly positive for type I collagen. Transgene-activated fat stromal cells formed rather fibrous tissue mainly composed of type I collagen. Unstimulated cells of the three different populations gave only rise to fibrous tissue.

CONCLUSIONS

Perichondrium/periosteum-derived cells and BMSC seem superior to cells isolated from fat with respect to forming hyaline cartilaginous tissue. A chondrogenic stimulus, e.g. by transfer of BMP-2 cDNA, appears to be required for initiation and support of chondrogenic differentiation.

The autologous osteochondral transplantation of the knee: clinical results, radiographic findings and histological aspects

INTRODUCTION

The osteochondral transplantation (OCT) is a well accepted treatment option for focal cartilage lesions in the knee joint, whereas the fate of the transplanted cartilage is still unclear and the clinical outcome is variable. The purpose of this study was to evaluate the histological character of autologous transplanted cartilage and to correlate technical aspects and the patients' history with the clinical outcome.

MATERIAL AND METHODS

The OCT was performed in 27 patients (median age of 32 (22-43) years) with a focal chondral lesion at the medial femoral condyle. We investigated the clinical outcome after a median follow-up of 13.5 (5-28) months using the Lysholm-score and the integration of the transplanted plugs using an MRI-scoring system. Biopsy specimens from representative patients (n = 8) were evaluated with histological staining and immunohistochemistry.

RESULTS

The median Lysholm-score was 80 (range 45-98). The wide range of the Lysholm-score in clinical outcome did not show significant differences in: follow-up, concomitant injuries, defect size or genesis. The MRI analysis revealed in all cases a regular osseous integration of the subchondral bone, but a failed chondral integration. The congruency of the plugs to the joint surface was often incorrect, however a correlation between the MRI-score and the clinical outcome could not be shown. Histology of the transplanted cartilage revealed small changes in immunohistochemistry after a relatively short-term follow-up, whereas the cartilage has still the typical hyaline character. Often, the surrounding cartilage consists of fibrous and granulation tissue.

CONCLUSION

The congruency of the joint surface can not be restored to the original status, particularly in larger defects with irregular shapes. However, we did not find any aspects which affected the function of the knee joint following OCT. It can be assumed that remaining lesions at the surrounding cartilage could maintain the inflammatory process and therefore maintain the pain and a low knee function. Further investigations are needed to specify the effects of the OCT on the transplanted cartilage and its influence on the later clinical outcome.

Multiple osteochondral arthroscopic grafting (mosaicplasty) for cartilage defects of the knee: prospective study results at 2-year follow-up

PURPOSE

To prospectively evaluate the mosaicplasty technique for treatment of femoral condyle cartilage lesions (Outerbridge grade IV) less than 2.5 cm2 in homogeneous group of young active patients.

TYPE OF STUDY

Case series.

METHODS

Thirty-seven patients (10 female, 27 male; mean age, 29.5 years) with full-thickness knee chondral lesions were treated by the arthroscopic mosaicplasty technique. All patients practiced sports. There were 12 ACL reconstructions, 11 medial meniscectomies, and 8 lateral meniscectomies associated; 10 meniscectomies, 9 ACL reconstructions, and 5 cartilage reparative operations had been previously performed. All patients were evaluated at a 2-year follow-up. The International Cartilage Repair Society (ICRS) form, return to sports, computed tomography, or magnetic resonance imaging were used for clinical evaluation. In some cases, second-look arthroscopy was performed.

RESULTS

The ICRS showed 78.3% good and excellent results; 27 patients returned to sports at the same level and 5 at a lower level, but 5 were not able to resume sports. Results in the lateral condyles were significantly better than those in medial condyles, and younger patients had a better clinical outcome than did older patients. Cases with associated surgery had better clinical results; previous surgery did not significantly influence the clinical outcome.

CONCLUSIONS

The results of this technique at medium-term follow-up are encouraging with 78.3% clinically satisfactory results. Better results can be obtained in young patients with associated surgery, with localized grade 4 lesions of the lateral condyles. This arthroscopic 1-step surgery appears to be a valid solution for the treatment of grade III-IV cartilage defects not more than 2.5 cm2.

LEVEL OF EVIDENCE

Level IV, Case Series.

Autologous cartilage implantation for full thickness articular cartilage defects of the knee

BACKGROUND

A variety of strategies have been employed for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty. These treatments are not always effective and when they are, the benefits may only be transitory. Unsuccessfully treated cartilage damage may progress to degenerative disease states and result in the need for a total knee replacement. In recent years the surgical implantation of healthy cartilage cells (autologous cartilage implantation [ACI] ) into damaged areas has been seen as an alternative option and is currently under investigation as a potential improvement over the current strategies for the management and treatment of articular cartilage defects.

OBJECTIVES

To determine the effectiveness of ACI in patients with full thickness articular cartilage defects of the knee.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group specialised register (May 2002), Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (1966 to June Week 4 2001), CINAHL (1982 to July Week 2 2001), EMBASE (1980 to 2001 Week 27), SPORTDiscus (1949 to June 2001), Current Contents (1993 Week 26 to 2001 Week 30) and the National Research Register (Issue 2, May 2002).

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, trochlea or patella.

DATA COLLECTION AND ANALYSIS

Two independent reviewers applied the entry criteria to identified studies.

MAIN RESULTS

No completed randomised controlled trials investigating this treatment were identified through the above searches. One possible trial has been placed in Studies Awaiting Assessment, awaiting translation of the full trial report. Ongoing trials currently underway will be incorporated in future updates of this review.

REVIEWER'S CONCLUSIONS

No information is available from RCTs which can influence current practice. Therefore, since current evidence is subject to the inherent weaknesses of case series or reports, ACI must currently be considered as a technology under investigation whose effectiveness is yet to be determined in well designed and conducted clinical trials. The results of ongoing randomised clinical trials will help improve this situation.