Health economics benefits following autologous chondrocyte transplantation for patients with focal chondral lesions of the knee

Long-term cost-effectiveness of matrix-associated chondrocyte implantation in the German health care system: a discrete event simulation

INTRODUCTION

Cartilage defects in the knee can be caused by injury, various types of arthritis, or degeneration. As a long-term consequence of cartilage defects, osteoarthritis can develop over time, often leading to the need for a total knee replacement (TKR). The treatment alternatives of chondral defects include, among others, microfracture, and matrix-associated autologous chondrocyte implantation (M-ACI). The purpose of this study was to determine cost-effectiveness of M-ACI in Germany with available mid- and long-term outcome data, with special focus on the avoidance of TKR.

MATERIALS AND METHODS

We developed a discrete-event simulation (DES) that follows up individuals with cartilage defects of the knee over their lifetimes. The DES was conducted with a status-quo scenario in which M-ACI is available and a comparison scenario with no M-ACI available. The model included 10,000 patients with articular cartilage defects. We assumed Weibull distributions for short- and long-term effects for implant failures. Model outcomes were costs, number of TKRs, and quality-adjusted life years (QALYs). All analyses were performed from the perspective of the German statutory health insurance.

RESULTS

The majority of patients was under 45 years old, with defect sizes between 2 and 7 cm² (mean: 4.5 cm²); average modeled lifetime was 48 years. In the scenario without M-ACI, 26.4% of patients required a TKR over their lifetime. In the M-ACI scenario, this was the case in only 5.5% of cases. Thus, in the modeled cohort of 10,000 patients, 2700 TKRs, including revisions, could be avoided. Patients treated with M-ACI experienced improved quality of life (22.53 vs. 21.21 QALYs) at higher treatment-related costs (18,589 vs. 14,134 € /patient) compared to those treated without M-ACI, yielding an incremental cost-effectiveness ratio (ICER) of 3376 € /QALY.

CONCLUSION

M-ACI is projected to be a highly cost-effective treatment for chondral defects of the knee in the German healthcare setting.

Algorithm for Treatment of Focal Cartilage Defects of the Knee: Classic and New Procedures

OBJECTIVE

To create a treatment algorithm for focal grade 3 or 4 cartilage defects of the knee using both classic and novel cartilage restoration techniques.

DESIGN

A comprehensive review of the literature was performed highlighting classic as well as novel cartilage restoration techniques supported by clinical and/or basic science research and currently being employed by orthopedic surgeons.

RESULTS

There is a high level of evidence to support the treatment of small to medium size lesions (<2-4 cm2) without subchondral bone involvement with traditional techniques such as marrow stimulation, osteochondral autograft transplant (OAT), or osteochondral allograft transplant (OCA). Newer techniques such as autologous matrix-induced chondrogenesis and bone marrow aspirate concentrate implantation have also been shown to be effective in select studies. If subchondral bone loss is present OAT or OCA should be performed. For large lesions (>4 cm2), OCA or matrix autologous chondrocyte implantation (MACI) may be performed. OCA is preferred over MACI in the setting of subchondral bone involvement while cell-based modalities such as MACI or particulated juvenile allograft cartilage are preferred in the patellofemoral joint.

CONCLUSIONS

Numerous techniques exist for the orthopedic surgeon treating focal cartilage defects of the knee. Treatment strategies should be based on lesion size, lesion location, subchondral bone involvement, and the level of evidence supporting each technique in the literature.

Effect of the defect localization and size on the success of third-generation autologous chondrocyte implantation in the knee joint

INTRODUCTION

Femoral and patellar cartilage defects with a defect size > 2.5 cm² are a potential indication for an autologous chondrocyte implantation (ACI). However, the influence of the localization and the absolute and relative defect size on the clinical outcome has not yet been determined. The purpose of this study is to analyze the influence of the localization and the absolute and relative defect size on the clinical outcome after third-generation autologous chondrocyte implantation.

METHODS

A total of 50 patients with cartilage defects of the knee were treated with third-generation autologous chondrocyte implantation (Novocart® 3D). A match paired analysis was performed of 25 treated femoral and 25 treated patella defects with a follow-up of three years. MRI data was used to do the manual segmentation of the cartilage layer throughout the knee joint. The defect size was determined by taking the defect size measured in the MRI in relation to the whole cartilage area. The clinical outcome was measured by the IKDC score and VAS pre-operatively and after six, 12, 24, and 36 months post-operatively.

RESULTS

IKDC and VAS scores showed a significant improvement from the baseline in both groups. Femoral cartilage defects showed significantly superior clinical results in the analyzed scores compared to patellar defects. The femoral group improved IKDC from 33.9 (SD 18.1) pre-operatively to 71.5 (SD 17.4) after three years and the VAS from 6.9 (SD 2.9) pre-operatively to 2.4 (SD 2.5) after three years. In the patellar group, IKDC improved from 36.1 (SD 12.6) pre-operatively to 54.7 (SD 20.3) after three years and the VAS improved from 6.7 (SD 2.8) pre-operatively to 3.4 (SD 2.) after three years. Regarding the defect size, results showed that the same absolute defect size at med FC (4.8, range 2-15) and patella (4.6, range 2-12) has a significantly different share of the total cartilaginous size of the joint compartment (med FC: 6.7, range 1.2-13.9; pat: 18.9, range 4.0-47.0). However, there was no significant influence of the relative defect size on the clinical outcome in either patellar or femoral localization.

CONCLUSION

Third-generation autologous chondrocyte implantation in ACI-treated femoral cartilage defects leads to a superior clinical outcome in a follow-up of three years compared with patellar defects. No significant influence of the defect size was found in either femoral or patellar cartilage defects.

Returning to Work After Articular Cartilage Repair Intervention: A Systematic Review

Background:

The process of returning to work after cartilage treatment has not been studied in depth, even though a better understanding of potential outcomes could lead to significant benefits for the general population.

Purpose:

To determine which surgical interventions are most effective in helping patients return to work after cartilage repair and to identify factors that affect the ability to return to work.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

This systematic review followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines in analyzing reports on articular cartilage treatment and return to work published from January 1966 (when the first system of classifying articular cartilage injuries based on the mechanism of injuries and type of lesions was developed) to January 2019. General surgical information and available clinical scores were used to assess outcomes.

Results:

Only 5 studies describing 283 patients were found to be relevant to our objectives and were therefore included in the analysis. Autologous chondrocyte implantation (ACI) and osteochondral allografts were the only 2 procedures for which information was included regarding patient return to work rates. The mean (overall) return-to-work time after a cartilage repair operation was 4.80 ± 3.02 months. ACI was the most common procedure (3 studies; 227 patients). Return to work after ACI or ACI with high tibial osteotomy (HTO) occurred in almost 100% of cases, whereas the rate of return to work was 51.78% for patients who underwent osteochondral allograft (P < .01); further, patients who had ACI or ACI+HTO returned to work sooner compared with patients who underwent osteochondral allograft. The Knee injury and Osteoarthritis Outcome Score (KOOS) and Single Assessment Numerical Evaluation (SANE) scores were significantly higher in patients who fully returned to work. No significant difference was found in rates of return to work after ACI related to sex, area of the lesion, or size of the defect.

Conclusion:

The vast majority of published results on articular cartilage repair do not include data on return to work. Although available data on articular cartilage repair in the general population reveal a high rate of return to work, including those patients treated with ACI, the data do not stratify patients by the type and demand of work. No randomized studies have examined return-to-work rates. Hence, authors should include these data in future studies. A refined definition of work intensity, rather than just return to work, may provide a clearer picture of the relative effectiveness of different surgical interventions. To that end, the authors propose a return to work prognostic score called the Prognostic Cartilage Repair Return to Work Score, or PROCART-RTW score.

Survival Analysis of Revision Autologous Chondrocyte Implantation for Failed ACI

BACKGROUND

Autologous chondrocyte implantation (ACI) provides a successful outcome for treating articular cartilage lesions. However, there have been very few reports on the clinical outcomes of revision ACI for failed ACI.

PURPOSE

To evaluate clinical outcomes in patients who underwent revision ACI of the knee for failure of an initial ACI and to determine the factors affecting the survival rate.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A review of a prospectively collected data set was performed from patients who underwent revision ACI of the knee for failure of an initial ACI between 1995 and 2014 by a single surgeon. The authors evaluated 53 patients (53 knees; mean age, 38 years) over a mean 11.2-year follow-up (range, 2-20). A total of 62 cartilage lesions were treated for failed graft lesions after an initial ACI, and 31 new cartilage lesions were treated at revision ACI, as there was progression of disease. Overall, 93 cartilage lesions (mean, 1.8 lesions per knee) with a total surface area of 7.4 cm² (range, 2.5-18 cm²) per knee were treated at revision ACI. Survival analysis was performed with the Kaplan-Meier method, with ACI graft failure or conversion to a prosthetic arthroplasty as the endpoint. The modified Cincinnati Knee Rating Scale, Western Ontario and McMaster Universities Osteoarthritis Index, visual analog scale, and 36-Item Short Form Health Survey were used to evaluate clinical outcomes. Patients also self-reported knee function and satisfaction. Standard radiographs were evaluated with Kellgren-Lawrence grades.

RESULTS

Survival rates were 71% and 53% at 5 and 10 years, respectively. Survival subanalysis revealed a trend that patients without previous cartilage repair procedures before an initial ACI had better survival rates than those with such procedures (81% vs 62% at 5 years, 64% vs 42% at 10 years, P = .0958). Patients with retained grafts showed significant improvement in pain and function, with a high level of satisfaction. At a mean 5.1 years postoperatively, 18 of 27 successful knees were radiographically assessed with no significant osteoarthritis progression. Outcomes for 26 patients were considered failures (mean, 4.9 years postoperatively), in which 15 patients had prosthetic arthroplasty (mean, 4.6 years) and the other 11 patients had revision cartilage repair (mean, 5.4 years) and thus could maintain their native knees.

CONCLUSION

Results of revision ACI for patients who failed ACI showed acceptable clinical outcomes. Revision ACI may be an option for young patients after failed initial ACI, particularly patients without previous cartilage repair procedures and those who desire to maintain their native knees.

Outcomes After Fresh Osteochondral Allograft Transplantation for Medium to Large Chondral Defects of the Knee

Background:

Articular cartilage defects of the knee can significantly impair function among young, high-demand patients. There are several techniques for chondral restoration, including osteochondral allograft transplantation (OCA), that may alleviate pain and re-create the native anatomy. However, clinical outcomes among athletic cohorts are limited.

Purpose:

To evaluate the efficacy and functional outcomes of OCA for medium to large osteochondral defects of the knee in physically active United States military servicemembers.

Study Design:

Case series; Level of evidence, 4.

Methods:

A military health care database was queried to identify all OCA procedures performed between January 2009 and March 2013. Inclusion criteria were army personnel with a minimum of 2 years’ follow-up. Exclusion criteria included incomplete follow-up, inaccurate coding, and nonmilitary status. Variables of interest included sex, age, lesion location, grade and size of the lesion, body mass index, tobacco use, preoperative and postoperative visual analog scale (VAS) scores for pain, and presence of perioperative complications. Overall failure was defined as the inability to return to preoperative functional activities because of persistent knee complaints (clinical failure) or a revision cartilage procedure or arthroplasty (surgical failure).

Results:

A total of 61 patients (52 male; mean age, 31.7 years) were identified, with a mean 46.2-month follow-up. The mean VAS pain score improved from 4.10 ± 2.17 preoperatively to 2.68 ± 2.73 postoperatively (P < .0009), and only 6 (9.8%) required a subsequent revision chondral procedure. Overall, 39 patients (63.9%) were able to return to a level of activity that allowed for the completion of military duties. Risk factors for clinical failure were preoperative body mass index, preoperative pain as measured on the VAS, and moderate to severe postoperative pain on the VAS. The risk factor for surgical failure was the presence of a complication. Risk factors for overall failure were the presence of a complication and moderate to severe postoperative pain on the VAS.

Conclusion:

OCA provided moderate success in retaining active-duty army servicemembers. Approximately two-thirds of patients undergoing OCA were able to return to their preinjury occupational activity, while approximately 57% of patients returned to prior levels without a subsequent revision chondral procedure or arthroplasty.

[Regeneration - A New Therapeutic Dimension in Otorhinolaryngology]

Regeneration as a therapeutic priniciple and regenerative medicine in general are promising new strategies to add new therapeutic dimensions to our current treatment options. Today, reconstructive surgery, drugs and implants such as the cochlear implant can replace the functions of damaged tissues. In contrast, regenerative therapies aim at the replacement of the damaged tissues themselves while at the same time replacing their lost tissue function. In this review article new technologies such as 3D-bioprinting and the application of decellularised tissues as biomaterials are introduced and explained. A summary of current preclinical and clinical regenerative studies in otorhinolaryngology is complementing these basic aspects.

A cost-effective cell- and matrix-based minimally invasive single-stage chondroregenerative technique developed with validated vertical translation methodology

Introduction The morbidity and significant health economic impact associated with the chondral lesion has led to a large number of strategies for therapeutic neochondrogenesis. The challenge has been to develop techniques that are cost effective single-stage procedures with minimal surgical trauma that have undergone rigorous preclinical scrutiny and robust reproducible assessment of effectiveness. A biological repair requires the generation of a cellular and matrix composite with appropriate signalling for chondrogenic differentiation. Methods and results A technique was developed that allowed chondrogenic primary (uncultured) cells from bone marrow aspirate concentrate, combined with a composite hydrophilic and fibrillar matrix to be applied arthroscopically to a site of a chondral lesion. The construct was tested in vitro and in animal experiments before clinical trials. Clinical trials involved 60 patients in a prospective study. Symptomatic International Cartilage Repair Society grade 3 and 4a lesions were mapped and treated. Pre- and postoperative clinical assessments showed statistically significant improved outcomes; Lysholm Knee Scoring Scale (mean 52.8 to > 76.4; P < 0.05) International Knee Documentation Committee (mean 39 to > 79 P < 0.05) and Knee injury and Osteoarthritis Outcome Score (64.5 to >89.2 P < 0.05). Postoperative magnetic resonance imaging was evaluated morphologically (magnetic resonance observation of cartilage repair tissue, average MOCART score 72) and qualitatively; the regenerate was comparable to native cartilage. Conclusions This technique is effective, affordable, requires no complex tools and delivers a single-stage treatment that is potentially accessible to any centre capable of performing arthroscopic surgery. Good clinical results were found to be sustained at five years of follow-up with a regenerate that appears hyaline like using multiple magnetic resonance measures.

A 20-Year Follow-up After First-Generation Autologous Chondrocyte Implantation

BACKGROUND

Treating articular cartilage defects is a demanding problem. Although several studies have reported durable and improved clinical outcomes after autologous chondrocyte implantation (ACI) over a long-term period, there is no report with over 20 years' follow-up.

PURPOSE

To evaluate clinical outcomes after first-generation ACI for the treatment of knees with disabling, large single and multiple cartilage defects for which patients wished to avoid prosthetic arthroplasty, with a minimum of 20 years' follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors reviewed prospectively collected data from 23 patients (24 knees; mean age, 35.4 years [range, 13-52 years]) undergoing ACI for the treatment of symptomatic, full-thickness articular cartilage lesions. A mean of 2.1 lesions per knee were treated over a mean total surface area of 11.8 cm² (range, 2.4-30.5 cm²) per knee. Kaplan-Meier survival analysis and functional outcome scores, including the modified Cincinnati Knee Rating System, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form-36 (SF-36), were used. Patients also self-reported an improvement in pain with a visual analog scale and a satisfaction survey.

RESULTS

The 20-year survival rate was 63% (95% CI, 40%-78%). The evaluation of the 15 knees with retained grafts demonstrated that all clinical scores except the WOMAC subscore for stiffness and SF-36 mental component summary score improved significantly and were sustained to 20 years postoperatively. Ninety-three percent of these patients rated knee-specific outcomes as good or excellent. The outcomes for 9 of 24 knees were considered failures, including 5 undergoing revision ACI and 4 being converted to arthroplasty at a mean of 1.7 and 5.9 years, respectively. Only 1 of 5 knees that underwent revision ACI was converted to arthroplasty at 1.9 years after the index surgery, and the other 4 patients were able to maintain their biological knee. Overall, 20 years later, 79% of patients maintained their native knee, for which they initially sought treatment, and were satisfied when evaluated.

CONCLUSION

First-generation ACI provided satisfactory survival rates and significant clinical improvements over a 20-year follow-up, which offers an important standard for comparison with newer-generation ACI technologies of the future.

Regenerative Cells for the Management of Osteoarthritis and Joint Disorders: A Concise Literature Review

As the global population ages, the prevalence of osteoarthritis (OA) and joint disorders represent a major cause of disability and a significant public health burden. As current approaches for the management of OA focus on slowing the progression of disease, without repairing the underlying damage, novel treatments are necessary to improve outcomes. Over the past decade, autologous cell-based therapies using regenerative cells from fat or bone marrow have become a major focus of research into new approaches for the treatment of osteoarthritis and joint disorders. This review is intended to summarize findings in existing literature and identify gaps in knowledge that should be addressed in order to advance the field. We acknowledge that some findings may appear inconsistent, but show that apparent inconsistency in the literature may be attributable to variation in source of cells, stage of disease, method of delivery, follow-up time, evaluation method, and a number of other idiosyncrasies of individual studies. Still, a number of themes emerge from the data and some broader conclusions may be drawn that can be used to guide future studies. Ultimately, we conclude that there is overwhelming evidence demonstrating the safety of the autologous cell-based therapies. Furthermore, the data support the claim that regenerative cells are capable of reversing progression of OA. Regenerative cells, and especially those from adipose tissue, represent a promising new approach for the treatment of OA. Future work should include appropriate controls, and focus on answering questions related to dose required, appropriate delivery vehicle, and the impact of multiple treatments. Additionally, future studies should look at short and long-term effects of the treatments, and use functional as well as radiologic methods to evaluate efficacy.

Long-term Outcomes of Autologous Chondrocyte Implantation in Adolescent Patients

BACKGROUND

Treating symptomatic articular cartilage lesions is challenging, especially in adolescent patients, because of longer life expectancies and higher levels of functional activity. For this population, long-term outcomes after autologous chondrocyte implantation (ACI) remain to be determined.

PURPOSE

To evaluate long-term outcomes in adolescents after ACI using survival analyses, validated outcome questionnaires, and standard radiographs.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We performed a review of prospectively collected data from patients who underwent ACI between 1996 and 2013. We evaluated 27 patients aged <18 years old (29 knees; mean age, 15.9 years) who were treated by a single surgeon for symptomatic, full-thickness articular cartilage lesions over a mean 9.6-year follow-up (median, 13 years; range, 2-19 years). A mean of 1.5 lesions per knee were treated over a mean total surface area of 6.2 cm² (range, 2.0-23.4 cm²) per knee. Survival analysis was performed using the Kaplan-Meier method, with graft failure as the end point. The modified Cincinnati Knee Rating Scale, Western Ontario and McMaster Universities Osteoarthritis Index, visual analog scale, and Short Form 36 scores were used to evaluate clinical outcomes. Patients also self-reported knee function and satisfaction. Standard radiographs were evaluated using Kellgren-Lawrence grades.

RESULTS

Both 5- and 10-year survival rates were 89%. All clinical scores improved significantly postoperatively. A total of 96% of patients rated knee function as better after surgery, and all patients indicated that they would undergo the same surgery again. Approximately 90% rated knee-specific outcomes as good or excellent and were satisfied with the procedure. At last follow-up, 12 of 26 successful knees were radiographically assessed (mean, 5.6 years postoperatively), with no significant osteoarthritis progression. Three knees were considered failures, which were managed by autologous bone grafting or osteochondral autologous transplantation. Twenty knees required subsequent surgical procedures. These were primarily associated with periosteum and were arthroscopically performed.

CONCLUSION

ACI resulted in satisfactory survival rates and significant improvements in function, pain, and mental health for adolescent patients over a long-term follow-up. ACI was associated with very high satisfaction postoperatively, despite the subsequent procedure rate being relatively high primarily because of the use of periosteum. If periosteum is used, this rate should be a consideration when discussing ACI with patients and their parents.

Editorial Commentary: Focal Cartilage Defects in Young Patients Indicate Autologous Chondrocyte Implantation Sooner Rather Than Later

Articular cartilage lesions, whether acute or chronic, are among the most common and difficult-to-treat conditions of the knee in the adolescent and athletic population. The results from a study in this issue as well as some in the previous literature suggest that autologous chondrocyte implantation yields long-term improvement in function and symptoms and may be a viable treatment for young to adult athletes or patients with high physical demands and a long active lifespan. No intervention in the young symptomatic patient will yield inferior results because it appears that no treatment over time has deleterious effects. Treatment in young athletes should include (1) early stabilization of ligament injuries, (2) resurfacing chondral defects, (3) correction of malalignment, (4) restoration of meniscal integrity, and (5) utilization of a chondroprotective strategy with orthobiological interventions.

2016 barriers to cartilage restoration

Cartilage restoration has flourished since the 1990s. The early pioneering work included cell therapy by Peterson, marrow stimulation by Johnson, osteochondral autograft treatments by Hangody, and osteochondral allografts by Gross. Since those early days, many scientists and clinicians have created "variations on a theme", markedly expanding the potential options for treating patients with symptomatic chondral lesions. Nevertheless, a variety of barriers exist between these new cartilage products and their clinical applications. These barriers may be categorized as cost, regulatory, insurance, and logistical issues. While absolute solutions will remain elusive, the current goal is to define these barriers as the first step toward solving these problems.

Articular cartilage repair: procedures versus products

This review discusses the current perspectives and practices regarding the treatment of articular cartilage injury. Specifically, the authors have delineated and examined articular cartilage repair techniques as either surgical procedures or manufactured products. Although both methodologies are used to treat articular cartilage injury, there are obvious advantages and disadvantages to the application of both, with the literature providing few recommendations on the most suitable regimen for the patient and surgeon. In recent times, cell-based tissue engineering products, predominantly autologous chondrocyte implantation, have been the subject of much research and have become clinically popular. Herein, we review the most used procedures and products in cartilage repair, compare and contrast their outcomes, and evaluate the issues that must be overcome in order to improve patient efficacy in the future.

One-step arthroscopic technique for the treatment of osteochondral lesions of the knee with bone-marrow-derived cells: three years results

Osteochondral lesions of the knee (OLK) are a common cause of knee pain and associated diseases. A new bone-marrow-derived mesenchymal stem cells technique has been developed for the treatment of OLK. 30 patients with OLK underwent arthroscopic one-step procedure. The bone marrow was harvested from the patients' posterior iliac crest and arthroscopically implanted with a scaffold into the lesion site. Clinical inspection and MRI were performed. Mean International Knee Documentation Committee (IKDC) score before surgery was 29.9 ± 13.2 and 85.4 ± 4.2 at 29 ± 4.1 months (p < 0.0005), while Knee injury and Osteoarthritis Outcome Score (KOOS) before surgery was 35.1 ± 11.9 and 87.3 ± 7.3 at 29 ± 4.1 months (p < 0.0005). Control MRI and bioptic samples showed an osteochondral regeneration of the lesion site. The one-step technique appears to be a good and reliable option for treatment of OLK at three years of follow-up. Level of evidence Case series, Level IV.

Maximizing phenotype constraint and extracellular matrix production in primary human chondrocytes using arginine-glycine-aspartate concentration gradient hydrogels

New systematic approaches are necessary to determine and optimize the chemical and mechanical scaffold properties for hyaline cartilage generation using the limited cell numbers obtained from primary human sources. Peptide functionalized hydrogels possessing continuous variations in physico-chemical properties are an efficient three-dimensional platform for studying several properties simultaneously. Herein, we describe a polyethylene glycol dimethacrylate (PEGDM) hydrogel system possessing a gradient of arginine-glycine-aspartic acid peptide (RGD) concentrations from 0mM to 10mM. The system is used to correlate primary human osteoarthritic chondrocyte proliferation, phenotype maintenance and extracellular matrix (ECM) production to the gradient hydrogel properties. Cell number and chondrogenic phenotype (CD14:CD90 ratios) were found to decline in regions with higher RGD concentrations, while regions with lower RGD concentrations maintained cell number and phenotype. Over three weeks of culture, hydrogel regions containing lower RGD concentrations experience an increase in ECM content compared to regions with higher RGD concentrations. Variations in actin amounts and vinculin organization were observed within the RGD concentration gradients that contribute to the differences in chondrogenic phenotype maintenance and ECM expression.

In vitro chondrogenesis transformation study of mouse dental pulp stem cells

A major challenge in the application of mesenchymal stem cells in cartilage reconstruction is that whether the cells are able to differentiate into fully mature chondrocytes before grafting. The aim of this study was to isolate mouse dental pulp stem cells (DPSC) and differentiate them into chondrocytes. For this investigation, morphological, molecular, and biochemical analyses for differentiated cells were used. To induce the chondrocyte differentiation, DPSC were cultured in chondrogenic medium (Zen-Bio, Inc.). Based on morphological analyses using toluidine blue staining, proteoglycan products appear in DPSC after 21 days of chondrocyte induction. Biochemical analyses in differentiated group showed that alkaline phosphatase activity was significantly increased at day 14 as compared to control (P < 0.05). Cell viability analyses during the differentiation to chondrocytes also showed that these cells were viable during differentiation. However, after the 14th day of differentiation, there was a significant decrease (P < 0.05) in the viability proportion among differentiated cells as compared to the control cells. In RT-PCR molecular analyses, mouse DPSC expressed Cd146 and Cd166 which indicated that these cells belong to mesenchymal stem cells. Coll I and Coll II markers showed high expression after 14 and 21 days, respectively. In conclusion, this study showed that DPSC successfully differentiated into chondrocytes.

Cost-effectiveness analysis of autologous chondrocyte implantation: a comparison of periosteal patch versus type I/III collagen membrane

BACKGROUND

Autologous chondrocyte implantation (ACI) involves the use of a periosteal patch (ACI-P) as a cover for transplanted chondrocytes. Theoretically, this periosteal patch provides mesenchymal stem cells and growth factors that encourage chondrocyte development/differentiation. However, there is a significant rate of graft hypertrophy with the use of periosteum compared with using a type I/III collagen patch (ACI-C). This type I/III collagen patch, although not approved by the United States Food and Drug Administration for ACI, has been used extensively in Europe and in an "off-label" nature in the United States as a cover during ACI.

PURPOSE

To examine the cost effectiveness of ACI and determine whether ACI-C is more cost effective than ACI-P.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 2.

METHODS

Outcome data and complication rates from patients undergoing ACI (ACI-P and ACI-C) were derived from the best evidence in the literature. Costs were determined by examining the typical patient charges undergoing ACI at a local orthopaedic hospital. The costs, results, and complication rates were used to develop a decision analysis model comparing ACI-P to ACI-C.

RESULTS

The cost of ACI-P was $66,752 and for ACI-C was $66,939.50 ($187.50 difference). The cost per quality-adjusted life year (QALY) for ACI-P was $9466 compared with $9243 for ACI-C. Sensitivity analysis was performed regarding the additional cost of the type I/III collagen patch ($780) in ACI-C as well as the rate of graft hypertrophy after ACI-P (25%). This analysis revealed that the cost of the type I/III collagen patch would have to reach $1721, or the rate of graft hypertrophy after ACI-P reduced to almost 11%, before ACI-P became more cost effective than ACI-C.

CONCLUSION

This cost-effectiveness analysis reveals that, while both ACI-P and ACI-C are cost effective, ACI-C is slightly more cost effective than ACI-P. This is likely secondary to the significant rate of patch-related complications associated with ACI-P, which is significantly reduced with ACI-C. Although the model is very sensitive to differences in outcomes between ACI-P and ACI-C, there is no high-quality evidence to suggest that there is a significant difference between the two. Thus, ACI-P becomes more cost effective if the cost of the type I/III collagen membrane is significantly increased or if the rate of graft hypertrophy after ACI-P were to be markedly reduced.

A prospective multicenter study on the outcome of type I collagen hydrogel-based autologous chondrocyte implantation (CaReS) for the repair of articular cartilage defects in the knee

BACKGROUND

The Cartilage Regeneration System (CaReS) is a novel matrix-associated autologous chondrocyte implantation (ACI) technique for the treatment of chondral and osteochondral lesions (Outerbridge grades III and IV). For this technology, no expansion of the chondrocytes in a monolayer culture is needed, and a homogeneous cell distribution within the gel is guaranteed.

PURPOSE

To report a prospective multicenter study of matrix-associated ACI of the knee using a new type I collagen hydrogel (CaReS).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From 2003 to 2008, 116 patients (49 women and 67 men; mean age, 32.5 ± 8.9 years) had CaReS implantation of the knee in 9 different centers. On the basis of the International Cartilage Repair Society (ICRS) Cartilage Injury Evaluation Package 2000, the International Knee Documentation Committee (IKDC) score, pain score (visual analog scale [VAS]), SF-36 score, overall treatment satisfaction and the IKDC functional status were evaluated. Patient follow-up was performed at 3, 6, and 12 months after surgery and annually thereafter. Mean follow-up was 30.2 ± 17.4 months (range, 12-60 months). There were 67 defects of the medial condyle, 14 of the lateral, 22 of the patella/trochlea, and 3 of the tibial plateau, and 10 patients had 2 lesions. The mean defect size was 5.4 ± 2.4 cm(2). Thirty percent of the defects were <4 cm(2) and 70% were >4 cm(2).

RESULTS

The IKDC score improved significantly from 42.4 ± 13.8 preoperatively to 70.5 ± 18.7 (P < .001) at latest follow-up. Global pain level significantly decreased (P < .001) from 6.7 ± 2.2 preoperatively to 3.2 ± 3.1 at latest follow-up. There also was a significant increase of both components of the SF-36 score. The overall treatment satisfaction was judged as very good or good in 88% by the surgeon and 80% by the patient. The IKDC functional knee status was grade I in 23.4%, II in 56.3%, III in 17.2%, and IV in 3.1% of the patients.

CONCLUSION

Matrix-associated ACI employing the CaReS technology for the treatment of chondral or osteochondral defects of the knee is a safe and clinically effective treatment that yields significant functional improvement and improvement in pain level. However, further investigation is necessary to determine the long-term viability and clinical outcome of this procedure.

Stem cell therapy for articular cartilage defects

BACKGROUND

Stem cells are easily accessible and have great potential for healing articular cartilage defects. These features make stem cell therapy an appealing approach for treating severely impaired joint function.

SOURCES OF DATA

Clinical and basic research articles and literature reviews.

AREAS OF AGREEMENT

Stem cells possess the potential to build articular cartilage. Malalignment and instability corrections and proper rehabilitation are crucial prerequisites for surgical procedures involving stem cell therapy. Smoking reduces the result.

AREAS OF CONTROVERSY

Ethical concerns remain unresolved. No standards are established for inducing stem cell potential, optimizing culturing media or harvesting. The risk of failure has not been determined.

GROWING POINTS

Surgical scaffolds can improve results. Care givers should focus on re-educating patients. Improved funding is needed for developing the therapy.

AREAS TIMELY FOR DEVELOPING RESEARCH

Define guidelines for stem cell therapy and demonstrate effectiveness.

Cell transplantation for articular cartilage defects: principles of past, present, and future practice

As articular cartilage has very limited self-repair capability, the repair and regeneration of damaged cartilage is a major challenge. This review aims to outline the past, present, and future of cell therapies for articular cartilage defect repair. Autologous chondrocyte implantation (ACI) has been used clinically for more than 20 years, and the short, medium, and long-term clinical outcomes of three generation of ACI are extensively overviewed. Also, strategies of clinical outcome evaluation, ACI limitations, and the comparison of ACI clinical outcomes with those of other surgical techniques are discussed. Moreover, mesenchymal stem cells and pluripotent stem cells for cartilage regeneration in vitro, in vivo, and in a few clinical studies are reviewed. This review not only comprehensively analyzes the ACI clinical data but also considers the findings from state-of-the-art stem cell research on cartilage repair from bench and bedside. The conclusion provides clues for the future development of strategies for cartilage regeneration.

Focal cartilage defects in the knee impair quality of life as much as severe osteoarthritis: a comparison of knee injury and osteoarthritis outcome score in 4 patient categories scheduled for knee surgery

BACKGROUND

Patients with focal cartilage defects in the knee may suffer from both pain and functional impairment. Treatment options are often insufficient. It is not known, however, to what extent their complaints affect quality of life, compared with other knee disorders. Knee Injury and Osteoarthritis Outcome Score (KOOS) is a validated global knee score suitable for comparison of patients with knee complaints attributable to different causes. Hypothesis Complaints because of localized cartilage defects in the knee reduce quality of life measured by KOOS to a different extent than those due to anterior cruciate ligament deficiency and osteoarthritis, when comparing patients within the working population scheduled for surgery.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3. Methods Previously registered KOOS baseline data on patients enrolled in different knee treatment studies were included in the present study; the patients were 18 to 67 years of age (working population) at data registration. The different patient categories were (1) patients with knee osteoarthritis enrolled for knee arthroplasty, (2) patients with knee osteoarthritis enrolled for osteotomies around the knee, (3) patients with focal cartilage lesions enrolled for cartilage repair, and (4) patients with anterior cruciate ligament-deficient knees enrolled for anterior cruciate ligament reconstruction. The KOOS subscale quality of life was the main parameter for comparison of complaints.

RESULTS

At preoperative baseline, patients with focal cartilage defects in the knee scored 27.5 on the KOOS subscale quality of life, not significantly different from the 28.8 and 27.2 in the patients with osteoarthritis enrolled for knee osteotomies and arthroplasties, respectively. For all the subscales of KOOS, the cartilage patients scored significantly lower than the patients with anterior cruciate ligament deficiency.

CONCLUSION

Patients with focal cartilage lesions have major problems with pain and functional impairment. Their complaints are worse than those of patients with anterior cruciate ligament-deficient knees, and quality of life is affected to the same extent as in patients scheduled for knee replacement.

Effect of bone morphogenetic protein-2 on normal and osteoarthritic human articular chondrocytes

In this study, we investigated whether Bone Morphogenetic Protein-2 (BMP-2) could modulate dedifferentiation, apoptosis and proliferation capacity in the normal and OA cultured chondrocytes. The articular chondrocytes from normal (n = 4) and OA (n = 4) cartilages were harvested separately. The chondrocytes were cultured in monolayer in the presence of 100 ng mL(-1) BMP-2 and 1% FBS as a test group and 1% FBS alone as a control group. Then, the chondrocytes were harvested and assessed for morphology with invert microscopy, proliferation by using MTT-assay and apoptosis with caspase-3 immunocytochemistry. The results indicated that the normal and the most OA chondrocytes showed round and polygonal appearance with chondrocyte-like morphology in BMP-2 treated groups after 6 days. The MTT proliferation test didn't show significant difference between test and control groups. The OA cells showed proliferation rate higher than the normal cells and significant difference in the presence of BMP-2 was observed (p<0.05). Positive immunostaining of caspase-3 in test and control groups was 1 and 20% in normal and 30 and 43% in OA groups, respectively. The percentage of apoptosis was reduced in the presence of BMP-2. In conclusion, it appears that BMP-2 involves in suppression of dedifferentiation and apoptosis processes of cultured human chondrocytes.

Autologous chondrocyte implantation to repair knee cartilage injury: ultrastructural evaluation at 2 years and long-term follow-up including muscle strength measurements

Autologous chondrocyte implantation (ACI) usually results in improvement in clinical scores. However, long-term isokinetic muscle strength measurements have not been reported. Biopsies from the repair tissue have shown variable proportions of hyaline-like cartilage. In this study, 21 consecutive patients were treated with autologous cartilage implantations in the knee. Mean size of the lesions was 5.5 cm(2). Follow-up arthroscopy with biopsy was performed at 2 years in 19 patients. The biopsies were examined with both light microscopy and transmission electron microscopy (TEM) techniques including immunogold analysis of collagen type 1. Patient function was evaluated with modified 10-point scales of the Cincinnati knee rating system obtained preoperatively and at 1 and 8.1 years. Isokinetic quadriceps and hamstrings muscle strength testing was performed at 1, 2 and 7.4 years. Light microscopy and TEM both showed predominately fibrous cartilage. The immunogold analysis showed a high percentage of collagen type I. At 7.4 years, the total work deficits when compared with the contra-lateral leg for isokinetic extension were 19.1 and 11.4%, and for isokinetic flexion 11.8 and 8.5% for 60 and 240 masculine/s, respectively. Mean pain score improved from 4.3 preoperatively to 6.3 at 1 year (p = 0.031) and 6.6 at 8.1 years (p = 0.013). Overall health condition score improved from 4.1 preoperatively to 6.1 at 1 year (p = 0.004) and 6.5 at 8.1 years (p = 0.008). Three patients later went through revision surgery with other resurfacing techniques and are considered failures. In summary, the formation of fibrous cartilage following ACI was confirmed by TEM with immunogold histochemistry. Although the functional scores were generally good, strength measurements demonstrated that the surgically treated leg remained significantly weaker.

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.

The relationship between the outcome of studies of autologous chondrocyte implantation and the presence of commercial funding

BACKGROUND

Autologous chondrocyte implantation (ACI) is an expensive treatment option for focal cartilage defects, and commercial funding of research is associated with a study reaching a positive conclusion. The purpose of this analysis is to compare outcomes (and levels of evidence) between published ACI outcome studies that were commercially funded and studies that were not commercially funded.

HYPOTHESIS

Commercially funded ACI literature could be commercially biased.

STUDY DESIGN

Comparative meta-analysis.

METHODS

MEDLINE was searched for human, knee, ACI, nonmembrane, English language, and clinical outcome studies. Studies were evaluated with regard to funding status (commercially funded or not commercially funded), outcomes, and levels of evidence. Outcomes and levels of evidence were evaluated and compared for commercially funded studies versus those that were not commercially funded.

RESULTS

Twenty-three studies were included; 16 (70%) were commercially funded. Pooled clinical outcome measures data were not significantly different (Lysholm, Modified Cincinnati, patient-reported Cincinnati, Tegner, pain Visual Analog Scale) when comparing commercially funded studies with those that were not commercially funded. However, distribution of levels of evidence was significantly lower (P = .045) for commercially funded studies.

CONCLUSION

Reassuringly, commercial funding of ACI studies did not result in a difference in published clinical outcomes versus those that were not commercially funded. However, the lower levels of evidence of commercially funded studies suggests that commercially funded ACI studies may be of less value to surgeons desiring to practice evidence-based medicine, and, in the future, commercial entities funding medical research could selectively fund studies of the highest levels of evidence.

Treatment outcomes of autologous chondrocyte implantation for full-thickness articular cartilage defects of the trochlea

BACKGROUND

The treatment of trochlear cartilage lesions is challenging given the likely presence of other patellofemoral joint pathologies, the topography of the area, and the limited available treatment options. Only 1 other study has examined the effectiveness of autologous chondrocyte implantation for lesions of the patellofemoral joint.

HYPOTHESIS

Patients treated with autologous chondrocyte implantation for moderate to large isolated lesions located on the trochlea will report improvement in the modified overall condition scale score of the Cincinnati Knee Rating System at a minimum 2-year follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Using modified scales of the Cincinnati Knee Rating System, 40 Cartilage Repair Registry patients rated their overall condition and symptoms at baseline and at a mean follow-up of 59 +/- 18 months. Factors likely to affect outcomes also were analyzed.

RESULTS

At baseline, patients were between ages 16 to 48 years, had a mean total defect size of 4.5 cm(2), and reported an overall condition score of 3.1 points (poor). Many failed a prior marrow-stimulation procedure (48%). Other procedures performed before baseline included tibiofemoral osteotomy in 23% and lateral release or Fulkerson for patella maltracking in 13%. Forty-three percent were receiving workers' compensation at baseline. Patients reported statistically significant improvement in their mean overall condition (3.1 points preoperatively to 6.4 points postoperatively), pain (2.6 to 6.2 points), and swelling (3.9 to 6.3 points) scores. Eleven patients experienced 17 subsequent procedures, and no patients had a failed implantation.

CONCLUSION

Autologous chondrocyte implantation appears to improve function and reduce symptoms in young to middle-aged patients with symptomatic, full-thickness articular cartilage lesions of the trochlea.

Mesenchymal stem cells in bone and cartilage repair: current status

The progression of rheumatoid pathologies, degenerative diseases, traumatologies, and their cortege of increasing medical, social and economical needs, has mandated the development of tissue repair and engineering technologies in orthopedic medicine. Mesenchymal stem cells (MSCs) are multipotent cells that can be extracted from large and relatively easily accessible compartments of the body, especially the bone marrow, and such cells are able to differentiate into adipogenic, chondrogenic and osteogenic precursors. The concept of using MSCs to repair tissues has progressively evolved, and the goal of cell-mediated therapy is to prolong the natural physiological abilities of healing, or substitute them, when these are lacking, failing or progressing too slowly. In recent years, the first clinical trials on the utility of MSCs, with or without scaffolds and/or growth factors, have been initiated. In this review, the authors focus on findings from preclinical research, clinical trials and case reports involving bone and cartilage repairs. New perspectives are considered regarding uses of cell types, cell delivery approaches and growth factors. They also consider the stringent conditions, constraints and considerations necessary to take cell-mediated therapy from bench to bedside.

Follow-up costs up to 5 years after conventional treatments in patients with cartilage lesions of the knee

In this retrospective cross-sectional study, we contacted patients who had been diagnosed with (and, if necessary, treated for) knee cartilage defects by arthroscopy at one of seven treatment centres in Germany between 1997 and 2001. In early 2003, patients completed a questionnaire on the health care resources they had used since the time of the arthroscopy. Based on this information, we determined follow-up costs. Data from a total of 1,708 patients were included in the final analysis. Of these, 1,070 were assigned to the initial operation (IO) group (61% men, 49+/-15 years; 39% women, 52+/-14 years) and 638 were assigned to the re-operation (RO) group (64% men, 44+/-13 years; 36% women, 47+/-14 years). The cumulative direct medical costs caused by knee complaints for the first 5 years following the arthroscopy were 1,984 Euro for the IO population and 4,203 Euro for the RO population. The cumulative indirect costs (i.e. costs associated with loss of productivity), however, amounted to 7,669 Euro and 15,265 Euro, respectively, and were thus almost four times as high as the cumulative direct costs. This is the first study that quantifies the considerable follow-up costs in patients who have undergone surgery for knee cartilage defects. As such, it may provide a yardstick for future treatments.

Patellofemoral full-thickness chondral defects treated with Hyalograft-C: a clinical, arthroscopic, and histologic review

BACKGROUND

Tissue engineering has emerged as a potential therapeutic option for cartilage regeneration.

HYPOTHESIS

Hyaluronan-based scaffolds seeded with autologous chondrocytes are a viable treatment for damaged articular surface of the patellofemoral joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Thirty-two chondral lesions with a mean size of 4.7 cm(2) were treated with Hyalograft-C. Twenty-two lesions were located in the patella and 10 in the trochlea. Sixteen patients had previous trauma, 3 had osteochondritis dissecans, and 13 had degenerative changes. Transplantations were carried out arthroscopically or through a miniarthrotomy incision. Eight patients had concomitant procedures, including patellar realignment (2), lateral release (3), and meniscectomy (3). Results were evaluated using the International Cartilage Repair Society-International Knee Documentation Committee scale, EuroQol EQ-5D form, and magnetic resonance imaging scans at 12 and 24 months. Six patients had second-look arthroscopy and biopsies. Statistical analysis was performed using the paired t test and Wilcoxon signed rank test.

RESULTS

The International Cartilage Repair Society-International Knee Documentation Committee and EuroQol EQ-5D scores demonstrated a statistically significant improvement (P < .0001). Objective preoperative data improved from 6/32 (18.8%) with International Knee Documentation Committee A or B to 29/32 (90.7%) at 24 months after transplantation. Mean subjective scores improved from 43.2 points preoperatively to 73.6 points 24 months after implantation. Magnetic resonance imaging studies at 24 months revealed 71% to have an almost normal cartilage with positive correlation to clinical outcomes. Second-look arthroscopies in 6 cases revealed the repaired surface to be nearly normal with biopsy samples characterized as hyaline-like in appearance.

CONCLUSION

Biodegradable scaffolds seeded with autologous chondrocytes can be a viable treatment for chondral lesions. The type of tissue repair achieved demonstrated histologic characteristics similar to normal articular cartilage. Long-term investigations are needed to determine the durability of the repair produced with this technique.

Cost and health status analysis after autologous chondrocyte implantation and mosaicplasty: a retrospective comparison

OBJECTIVES

Chondral defects of the knee cartilage are prevalent. Autologous chondrocyte implantation (ACI) and mosaicplasty are increasingly used to treat symptomatic knee defects. This study assessed the costs and health status outcomes after ACI and mosaicplasty.

METHODS

Patients were eligible to participate in this cross-sectional study if they received ACI or mosaicplasty at the Royal National Orthopaedic Hospital between 1997 and 2001 or were on a waiting list for ACI. Secondary-care resource use was collected to 2 years postoperatively using a resource collection proforma. Participants responded to postal questions about sociodemographic characteristics and knee-related (Modified Cincinnati Knee Rating System) and general health status (EQ-5D).

RESULTS

Fifty-three ACI, twenty mosaicplasty, and twenty-two patients waiting for ACI participated. The average cost per patient was higher for ACI (10,600 pounds sterling: 95 percent confidence interval [CI], 10,036 pounds sterling-11,214 pounds sterling) than mosaicplasty (7,948 pounds sterling: 95 percent CI, 6,957 pounds sterling-9,243 pounds sterling). Postoperatively, ACI and mosaicplasty patients (combined) experienced better health status than those waiting for ACI. ACI patients tended to have better health status outcomes than mosaicplasty patients (not statistically significant). Estimated average EQ-5D social tariff improvements for quality-adjusted life year (QALY) calculations were 0.23 (ACI) and 0.06 (mosaicplasty). Average costs per QALY were 23,043 pounds sterling (ACI) and 66,233 pounds sterling (mosaicplasty). The incremental cost effectiveness ratio (ICER) for providing ACI over mosaicplasty was 16,349 pounds sterling.

CONCLUSIONS

Average costs were higher for ACI than mosaicplasty. However, both the estimated cost per QALY and ICER for providing ACI over mosaicplasty fell beneath an implicit English funding threshold of 30,000 pounds sterling per QALY. Prospective studies should include measures of utility to confirm the estimated cost utility ratios of ACI and mosaicplasty.

Autologous chondrocyte implantation: a systematic review

OBJECTIVE

To critically analyze the existing literature relating to autologous chondrocyte implantation (ACI) and thereby to ascertain whether the technique is clinically effective and safe.

METHODS

Using predefined criteria, we searched a number of automated databases, such as MEDLINE, EMBASE, Cochrane, CRD, etc., for relevant articles, which were then analyzed by two independent reviewers.

RESULTS

Three clinical trials and nine case series were evaluated. The clinical trials yielded no evidence that ACI was superior to the therapeutic alternatives with which it was compared. In contrast, the case series revealed an improvement in patients. However, as with the clinical trials, the follow-up periods were usually very short. In general, few adverse effects were observed, indicating that ACI is a safe technique.

CONCLUSION

Available data afford no evidence that ACI is more effective than other conventional techniques in treating chondral lesions of the knee.

[Cartilage cell transplantation as an alternative to endoprosthesis]

The incidence of cartilage lesions is high. Due to pain and loss of function, long-term therapy is often necessary. Isolated, full-thickness articular cartilage lesions with a diameter of 4 cm2 are indications for chondrocyte transplantation. Many outcome studies report good long-term results. In recent years, the cultivation of chondrocytes has changed. Histologic investigations show hyalin-like cartilage after transplantation. Large cartilage lesions facing each other are a therapeutic dilemma in young patients. Implanting unicondylar or bicondylar prostheses is sometimes the last resort for these patients, and there are several reports of good clinical outcome. Cartilage transplantation has until now been recommended for patients younger than 50. It is not an alternative to joint replacement.

Process design of chondrocyte cultures with monolayer growth for cell expansion and subsequent three-dimensional growth for production of cultured cartilage

The subculture of rabbit chondrocytes with serial passaging was carried out for cell expansion on a collagen-coated surface, and the morphological transition of round-shaped cells to spindle-shaped ones was examined. The observation of cytoskeletal formation by staining F-actin and vinculin supported the view that the round-shaped cells were in the process of differentiation with immature stress fibers relating to less cellular polarity. The cellular morphology was estimated in terms of the distribution of roundness, R(C), during the subculturing on the collagen substrate. The frequency of the number of round-shaped cells, which was defined as the ratio of the number of cells with R(C) >0.9 against the total cell number, was correlated in a logarithmic formula with the number of population doublings during the subcultures. Kinetic models were adopted for the process design of the combined culture of chondrocytes with monolayer growth on the collagen substrate and subsequent three-dimensional growth in Atelocollagen gel, employing the boundary conditions based on the population balance between differentiated and dedifferentiated cells. The combined culture was performed successfully according to the process design scheduled as monolayer growth for 240 h and three-dimensional growth for 264 h, the number of seed cells being 68% of that in the conventional culture for 504 h where monolayer growth for cell expansion was not included.

Articular cartilage engineering with Hyalograft C: 3-year clinical results

The use of tissue engineering for cartilage repair has emerged as a potential therapeutic option and has led to the development of Hyalograft C, a tissue-engineered graft composed of autologous chondrocytes grown on a scaffold entirely made of HYAFF 11, an esterified derivative of hyaluronic acid. Here we present the results of an ongoing multicenter clinical study conducted with the primary objective to investigate the subjective symptomatic, functional and health-related quality of life outcomes of patients treated with Hyalograft C. Clinical results on the cohort of 141 patients with followup assessments ranging from 2 to 5 years (average followup time: 38 months), are reported. At followup 91.5% of patients improved according to the International Knee Documentation Committee subjective evaluation; 76% and 88% of patients had no pain and mobility problems respectively assessed by the EuroQol-EQ5D measure. Furthermore, 95.7% of the patients had their treated knee normal or nearly normal as assessed by the surgeon; cartilage repair was graded arthroscopically as normal or nearly normal in 96.4% of the scored knees; the majority of the second-look biopsies of the grafted site histologically were assessed as hyaline-like. Importantly, a very limited complication rate was recorded in this study. The positive clinical results obtained indicate that Hyalograft C is a safe and effective therapeutic option for the treatment of articular cartilage lesions.

LEVEL OF EVIDENCE

Therapeutic study, Level III-2 (retrospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

[Mid-term results of autologous chondrocyte transplantation in knee and ankle. A one- to six-year follow-up study]

BACKGROUND

The reimplantation of autologous chondrocytes is a new technique in reconstruction of cartilage defects; initial results achieved with this technique have been promising. In an arthroscopic procedure, scales of cartilage are obtained from intact cartilage. The chondrocytes are then multiplied in special laboratories. A few weeks later, in a second procedure, the cartilage defect is filled with the cell suspension and closed with a flap of periosteum.

METHOD

At our department, autologous chondrocyte transplantation (ACT) has been used in 10 patients since 1996, in 6 cases in the knee joint, and in 4 cases in the ankle joint. The mean age of the patients was 30 years. The mean size of the defect was 4 cm(2). In 4 patients, a parallel surgical procedure was required at the time of removal.

RESULTS

The mean duration of follow-up was 21/2 years. Six patients had good to excellent results, 3 patients had moderate results, and one patient a poor result. The modified Cincinnati rating scale was improved from 2.4 to 7.1 points, and the Lysholm score from 59.2 to 86.6 points. The AOFAS score for ankle joints had improved from 33 to 76.

CONCLUSION

We were able to show that ACT achieves improvement in the knee as well as ankle joint in the majority of patients. ACT appears to be a promising therapeutic concept for both joints.

A kinetic modeling of chondrocyte culture for manufacture of tissue-engineered cartilage

For repairing articular cartilage defects, innovative techniques based on tissue engineering have been developed and are now entering into the practical stage of clinical application by means of grafting in vitro cultured products. A variety of natural and artificial materials available for scaffolds, which permit chondrocyte cells to aggregate, have been designed for their ability to promote cell growth and differentiation. From the viewpoint of the manufacturing process for tissue-engineered cartilage, the diverse nature of raw materials (seeding cells) and end products (cultured cartilage) oblige us to design a tailor-made process with less reproducibility, which is an obstacle to establishing a production doctrine based on bioengineering knowledge concerning growth kinetics and modeling as well as designs of bioreactors and culture operations for certification of high product quality. In this article, we review the recent advances in the manufacturing of tissue-engineered cartilage. After outlining the manufacturing processes for tissue-engineered cartilage in the first section, the second and third sections, respectively, describe the three-dimensional culture of chondrocytes with Aterocollagen gel and kinetic model consideration as a tool for evaluating this culture process. In the final section, culture strategy is discussed in terms of the combined processes of monolayer growth (ex vivo chondrocyte cell expansion) and three-dimensional growth (construction of cultured cartilage in the gel).

Bone morphogenetic protein (BMP)-2 enhances the expression of type II collagen and aggrecan in chondrocytes embedded in alginate beads

OBJECTIVE

For autologous chondrocyte transplantation (ACT) chondrocytes are expanded in vitro. During expansion these cells may dedifferentiate. This change in phenotype is characterized by a raised expression of type I collagen and a decrease in type II collagen expression. Since high expression of type II collagen is of central importance for the properties of hyaline cartilage, we investigated if the growth factor bone morphogenetic protein-2 (BMP-2) may modulate the chondrogenic phenotype in monolayer cell cultures and in three-dimensional culture systems.

DESIGN

Chondrocytes from articular knee cartilage of 11 individuals (average age: 39.8 years) with no history of joint disease were isolated and seeded either in monolayer cultures or embedded in alginate beads in presence or absence of human recombinant BMP-2 (hr-BMP-2). Then, cells were harvested and analysis of the chondrogenic phenotype was performed using quantitative RT-PCR, immunocytochemistry and ELISA.

RESULTS

Addition of BMP-2 to chondrocytes expanded in two-dimensional (2D) cultures during the first subculture (P1) had no effect on mRNA amounts encoding type II collagen and interleukin-1beta (IL-1beta). In contrast, seeding chondrocytes in three-dimensional (3D) alginate cultures raised type II collagen expression significantly and addition of BMP-2 enhanced this effect.

CONCLUSIONS

We conclude that chondrocytes during expansion for ACT may benefit from BMP-2 activation only when seeded in an appropriate 3D culture system.

Treatment of osteochondritis dissecans of the knee with autologous chondrocyte transplantation: results at two to ten years

BACKGROUND

Osteochondritis dissecans of the knee is a challenging clinical problem. We previously reported on the early successful results of autologous chondrocyte transplantation for the treatment of focal cartilage defects. The purpose of the present study was to assess the intermediate to long-term results of this technique in a large group of patients with osteochondritis dissecans.

METHODS

Fifty-eight patients with radiographically documented osteochondritis dissecans of the knee underwent treatment with autologous chondrocyte transplantation between 1987 and 2000 and were assessed clinically with use of standard rating scales. Twenty-two patients consented to arthroscopic second-look evaluation of graft integrity.

RESULTS

The mean age of the patients at the time of autologous chondrocyte transplantation was 26.4 years (range, fourteen to fifty-two years). Seven patients were less than eighteen years old. Thirty-five patients (60%) had juvenile-onset disease, and forty-eight patients (83%) had had a mean of 2.1 prior operations. The defect was located on the medial femoral condyle in thirty-nine patients and on the lateral femoral condyle in nineteen. The mean lesion size was 5.7 cm (2) (range, 1.5 to 12.0 cm (2) ), and the mean defect depth was 7.8 mm (range, 4 to 15 mm). After a mean duration of follow-up of 5.6 years, 91% of the patients had a good or excellent overall rating on the basis of a clinician evaluation and 93% had improvement on a patient self-assessment questionnaire. The Tegner-Wallgren, Lysholm, and Brittberg-Peterson VAS scores were all improved. The macroscopic quality of graft integrity averaged 11.2 on a 12-point scale, with only one graft having a score of <9 points. Two patients had a failure of treatment in the early postoperative period. Only one patient who had had a good or excellent rating at two years had a decline in clinical status at the time of the latest follow-up.

CONCLUSIONS

Treatment of osteochondritis dissecans lesions of the knee with autologous chondrocyte transplantation produces an integrated repair tissue with a successful clinical result in >90% of patients. We recommend the wider use of autologous chondrocyte transplantation for this condition.