Matrix-assisted autologous chondrocyte implantation into a 14cm(2) cartilage defect, caused by steroid-induced osteonecrosis

Longtime Outcome After Intraosseous Application of Autologous Mesenchymal Stromal Cells in Pediatric Patients and Young Adults with Avascular Necrosis After Steroid or Chemotherapy

Avascular necrosis (AVN) is a severe complication of immunosuppressant therapy or chemotherapy. A beneficial AVN therapy with core decompression (CD) and intraosseous infusion of mesenchymal stromal cells (MSCs) has been described in adult patients, but there are only few data on MSC applications in pediatric and young adult patients (PYAP). Between 2006 and 2015, 14 AVN lesions of 10 PYAP (6 females) with a median age of 16.9 years (range 8.5-25.8 years) received CD and intraosseous application of autologous MSCs. Data of these patients were analyzed regarding efficacy, safety, and feasibility of this procedure as AVN therapy and compared with a control group of 13 AVN lesions of 11 PYAP (5 females) with a median age of 17.9 years (range 13.5-27.5 years) who received CD only. During the follow-up analysis [MSC group: median 3.1 (1.6-5.8) years after CD; CD group: median 2.0 (1.5-8.5) years after CD], relative lesion sizes (as assessed by magnetic resonance imaging) compared with the initial lesion volume, were significantly lower (P < 0.05) in the MSC group (volume reduction to a median of 18.5%) when compared with the CD group (58.0%). One lesion in the MSC group comprised a complete remission. Size progression was not observed in either group. Clinical improvement (pain, mobility) was not significantly different between the two groups. None of the patients experienced treatment-related adverse effects. CD and additional MSC application was regarded safe, effective, feasible, and superior in reducing the lesion size when compared with CD only. Prospective, randomized clinical trials are needed to further evaluate these findings.

Osteonecrosis in pediatric cancer survivors: Epidemiology, risk factors, and treatment

Several treatment regimens for childhood malignancies have been associated with the development of osteonecrosis, including radiation therapy, glucocorticoid medications, immunotherapy (including anti-angiogenic agents), and several chemotherapeutic agents. Adolescents older than 10 years are at greatest risk of developing osteonecrosis within 1 year of initiating therapy. Screening with magnetic resonance imaging in this high-risk population may be a useful method for detecting osteonecrosis. Surgery may be required for lesions that have progressed substantially despite nonoperative interventions.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Chondrogenic predifferentiation of human mesenchymal stem cells in collagen type I hydrogels

Hyaline cartilage displays a limited regenerative potential. Consequently, therapeutic approaches have been developed to treat focal cartilage lesions. Larger-sized lesions are commonly treated by osteochondral grafting/mosaicplasty, autologous chondrocyte implantation (ACI) or matrix-induced chondrocyte implantation (MACI). As an alternative cell source to chondrocytes, multipotent mesenchymal stem cells (MSCs) are regarded a promising option. We therefore investigated the feasibility of pre-differentiating human MSCs incorporated in hydrogels clinically applied for MACI (CaReS®). MSC-laden hydrogels were cast and cultured over 10 days in a defined chondrogenic differentiation medium supplemented with TGF-β1. This was followed by an 11-day culture in TGF-β1 free media. After 21 days, considerable contraction of the hydrogels was observed. Histochemistry showed cells of a chondrocyte-like morphology embedded in a proteoglycan-rich extracellular matrix. Real-time polymerase chain reaction (RT-PCR) analysis showed the expression of chondrogenic marker genes, such as collagen type II and aggrecan. In summary, we demonstrate that chondrogenic differentiation of human mesenchymal stem cells embedded in collagen type I hydrogels can be induced under the influence of TGF-β1 over a period of 10 days.

Management and treatment of osteonecrosis in children and adolescents with acute lymphoblastic leukemia

There is no consensus regarding how to manage osteonecrosis in pediatric acute lymphoblastic leukemia patients. Therefore, we performed a quality assessment of the literature with the result of a search strategy using the MESH terms osteonecrosis, children, childhood cancer, surgery, bisphosphonates, 6 hydroxymethyl-glutaryl CoA reductase inhibitors, anticoagulants and hyperbaric oxygen, and terms related to these MESH terms. A randomized controlled trial showed that osteonecrosis can be prevented by intermittent, instead of continuous, corticosteroid administration. The studies on interventions after onset of osteonecrosis were of low-quality evidence. Seven pediatric acute lymphoblastic leukemia studies described non-surgical interventions; bisphosphonates (n=5), hyperbaric oxygen therapy (n=1), or prostacyclin analogs (n=1). Safety and efficacy studies are lacking. Five studies focused on surgical interventions; none was of sufficient quality to draw definite conclusions. In conclusion, preventing osteonecrosis is feasible in a proportion of the pediatric acute lymphoblastic leukemia patients by discontinuous, instead of continuous, steroid scheduling. The questions as to how to treat childhood acute lymphoblastic leukemia patients with osteonecrosis cannot be answered as good-quality studies are lacking.

Cartilaginous constructs using primary chondrocytes from continuous expansion culture seeded in dense collagen gels

Cell-based therapies such as autologous chondrocyte implantation require in vitro cell expansion. However, standard culture techniques require cell passaging, leading to dedifferentiation into a fibroblast-like cell type. Primary chondrocytes grown on continuously expanding culture dishes (CE culture) limits passaging and protects against dedifferentiation. The authors tested whether CE culture chondrocytes were advantageous for producing mechanically competent cartilage matrix when three-dimensionally seeded in dense collagen gels. Primary chondrocytes, grown either in CE culture or passaged twice on static silicone dishes (SS culture; comparable to standard methods), were seeded in dense collagen gels and cultured for 3 weeks in the absence of exogenous chondrogenic growth factors. Compared with gels seeded with SS culture chondrocytes, CE chondrocyte-seeded gels had significantly higher chondrogenic gene expression after 2 and 3 weeks in culture, correlating with significantly higher aggrecan and type II collagen protein accumulation. There was no obvious difference in glycosaminoglycan content from either culture condition, yet CE chondrocyte-seeded gels were significantly thicker and had a significantly higher dynamic compressive modulus than SS chondrocyte-seeded gels after 3 weeks. Chondrocytes grown in CE culture and seeded in dense collagen gels produce more cartilaginous matrix with superior mechanical properties, making them more suitable than SS cultured cells for tissue engineering applications.

Matrix assisted autologous chondrocyte transplantation for cartilage treatment: A systematic review

OBJECTIVES

Matrix-assisted autologous chondrocyte transplantation (MACT) has been developed and applied in the clinical practice in the last decade to overcome most of the disadvantages of the first generation procedures. The purpose of this systematic review is to document and analyse the available literature on the results of MACT in the treatment of chondral and osteochondral lesions of the knee.

METHODS

ALL STUDIES PUBLISHED IN ENGLISH ADDRESSING MACT PROCEDURES WERE IDENTIFIED, INCLUDING THOSE THAT FULFILLED THE FOLLOWING CRITERIA: 1) level I-IV evidence, 2) measures of functional or clinical outcome, 3) outcome related to cartilage lesions of the knee cartilage.

RESULTS

The literature analysis showed a progressively increasing number of articles per year. A total of 51 articles were selected: three randomised studies, ten comparative studies, 33 case series and five case reports. Several scaffolds have been developed and studied, with good results reported at short to medium follow-up.

CONCLUSIONS

MACT procedures are a therapeutic option for the treatment of chondral lesions that can offer a positive outcome over time for specific patient categories, but high-level studies are lacking. Systematic long-term evaluation of these techniques and randomised controlled trials are necessary to confirm the potential of this treatment approach, especially when comparing against less ambitious traditional treatments.

Scaffold-based repair for cartilage healing: a systematic review and technical note

PURPOSE

The aim of this systematic review was to address the treatment of chondral and osteochondral knee lesions through the use of scaffolds, by showing surgical options and results of this scaffold-based repair approach for the healing of the articular surface.

METHODS

All studies published in English addressing cartilage scaffold-based treatment were identified, including those that fulfilled the following criteria: (1) Levels I to IV evidence addressing the outlined areas of interest, (2) measures of functional or clinical outcome, (3) knee cartilage lesions, and (4) minimum of 2 years of follow-up.

RESULTS

The analysis showed a progressively increasing number of articles per year from 1995 to February 2012. The number of selected articles was 51, with 40 focusing on 2-step procedures and 11 focusing on 1-step procedures. The evaluation of evidence level showed 3 randomized studies, 10 comparative studies, 33 case series, and 5 case reports.

CONCLUSIONS

Regenerative scaffold-based procedures are emerging as a therapeutic option for the treatment of chondral lesions, but well-designed studies are lacking. Systematic long-term evaluation of these techniques and randomized studies are necessary to confirm the potential of this treatment approach, especially compared with the available traditional treatments. Different 1-step scaffold-based strategies are emerging to simplify the procedure and reduce costs.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

The incidence of alcohol-associated osteonecrosis of the knee is lower than the incidence of steroid-associated osteonecrosis of the knee: an MRI study

OBJECTIVE

The purpose of the study was to clarify the incidence of alcohol-associated osteonecrosis of the knee using MRI.

METHODS

A total of 131 patients (56 women and 75 men) with osteonecrosis of the femoral head were enrolled; 60 patients had a history of alcohol abuse and 71 had previously received steroids. All patients underwent MRI of the knee. The incidence of alcohol-associated osteonecrosis of the knee was compared with that of steroid-associated osteonecrosis of the knee. Predictive factors of alcohol- and steroid-associated osteonecrosis of the knee were also evaluated.

RESULTS

The incidence of alcohol-associated osteonecrosis of the knee was lower than that of steroid-associated osteonecrosis of the knee (18.3 vs 54.9%; P < 0.001, Fisher's exact probability test). No significant difference in weekly alcohol consumption was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee. No significant difference in daily maximum steroid doses was observed between patients with osteonecrosis of the knee and those without osteonecrosis of the knee.

CONCLUSION

The present study revealed that the incidence of alcohol-associated osteonecrosis of the knee is lower than that of steroid-associated osteonecrosis of the knee.

Management of osteonecrosis in children and young adults with acute lymphoblastic leukaemia

Osteonecrosis is a disabling complication in children and young adults with acute lymphoblastic leukaemia. It can affect any or multiple joints but the hip and knee are most frequently involved and a cause of long-term disability. The problem is almost exclusively that of older children and young adults of whom over 70% have asymptomatic changes on screening magnetic resonance imaging and 15-20% have resulting symptoms. Dexamethasone is associated with a higher risk than prednisolone in US but not European or UK trials and alternate week scheduling of dexamethasone in the intensification course is associated with a lower risk than a continuous 3-week schedule in US trials. Genetic factors and obesity contribute to the risk, as do metabolic abnormalities caused by drugs, such as asparaginase, which increase tissue exposure to steroids. Management is primarily supportive but a minority of patients require surgical intervention including replacement of the affected joint. A variety of surgical techniques and, latterly, bisphophonates, have been tried to prevent progression but their efficacy remains uncertain. Whether patients should continue to receive steroids after diagnosis of osteonecrosis is uncertain but most trial investigators recommend stopping them after completion of the intensification phase of treatment.