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

A randomized trial comparing accelerated and traditional approaches to postoperative weightbearing rehabilitation after matrix-induced autologous chondrocyte implantation: findings at 5 years

BACKGROUND

While structured postoperative rehabilitation after matrix-induced autologous chondrocyte implantation (MACI) is considered critical, very little has been made available on how best to progressively increase weightbearing and exercise after surgery.

HYPOTHESIS

A significant improvement will exist in clinical and magnetic resonance imaging (MRI)-based scoring measures to 5 years after surgery. Furthermore, there will be no significant differences in outcomes in MACI patients at 5 years when comparing a traditional and an accelerated postoperative weightbearing regimen. Finally, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with graft outcome.

STUDY DESIGN

Randomized controlled trial; level of evidence, 1.

METHODS

Clinical and radiological outcomes were studied in 70 patients who underwent MACI to the medial or lateral femoral condyle, in conjunction with either an "accelerated" or a "traditional" approach to postoperative weightbearing rehabilitation. Under the accelerated protocol, patients reached full weightbearing at 8 weeks after surgery, compared with 11 weeks for the traditional group. Clinical measures (knee injury and osteoarthritis outcome score [KOOS], short-form health survey [SF-36], visual analog scale [VAS], 6-minute walk test, and knee range of motion) were assessed before surgery and at 3, 6, 12, and 24 months and 5 years after surgery. High-resolution MRI was undertaken at 3, 12, and 24 months and 5 years after surgery and assessed 8 previously defined pertinent parameters of graft repair as well as a combined MRI composite score. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated.

RESULTS

Of the 70 patients recruited, 63 (31 accelerated, 32 traditional) underwent clinical follow-up at 5 years; 58 (29 accelerated, 29 traditional) also underwent radiological assessment. A significant time effect (P < .05) was demonstrated for all clinical and MRI-based scores over the 5-year period. While the VAS demonstrated significantly less frequent pain at 5 years in the accelerated group, there were no other significant differences between the 2 groups. Between 24 months and 5 years, a significant improvement (P < .05) in both groups was observed for the sport and recreation subscale of the KOOS as well as a significant decrease (P < .05) in active knee extension for the traditional group. There were no significant differences (P > .05) in the MRI-based scores between 24 months and 5 years after surgery. Patient age and defect size exhibited significant negative correlations (P < .05) with several MRI-based outcomes at 5 years, while there were no significant correlations (P > .05) between clinical and MRI-based outcomes. At 5 years after surgery, 94% and 95% were satisfied with the ability of MACI to relieve their knee pain and improve their ability to undertake daily activities, respectively.

CONCLUSION

The outcomes of this randomized trial demonstrate a safe and effective accelerated rehabilitation protocol as well as a regimen that provides comparable, if not superior, clinical outcomes to patients throughout the postoperative timeline.

Supporting Biomaterials for Articular Cartilage Repair

Orthopedic surgeons and researchers worldwide are continuously faced with the challenge of regenerating articular cartilage defects. However, until now, it has not been possible to completely mimic the biological and biochemical properties of articular cartilage using current research and development approaches. In this review, biomaterials previously used for articular cartilage repair research are addressed. Furthermore, a brief discussion of the state of the art of current cell printing procedures mimicking native cartilage is offered in light of their use as future alternatives for cartilage tissue engineering. Inkjet cell printing, controlled deposition cell printing tools, and laser cell printing are cutting-edge techniques in this context. The development of mimetic hydrogels with specific biological properties relevant to articular cartilage native tissue will support the development of improved, functional, and novel engineered tissue for clinical application.

Early-term effect of adult chondrocyte transplantation in an osteoarthritis animal model

In this study, we investigated the efficacy of the transplantation of autologous articular chondrocytes seeded onto a hyaluronan-based scaffold, known as Hyaff(®)-11, on the treatment of early cartilage lesions in a rabbit osteoarthritis (OA) model. The hypothesis of the study was that this treatment could enhance cartilage repair after OA induction. OA was surgically induced by Anterior Cruciate Ligament Transection (ACLT) in thirty rabbits. Animals were divided into three groups, according to treatment: group 1: ACLT; group 2: Chondrocytes+Hyaff-11; and group 3: Hyaff-11 alone. The animals were euthanized, respectively, at 3 and 6 months after the treatment. Histomorphometrical analyses were performed by means of fibrillation index, cartilage thickness, and subchondral bone thickness evaluations. Histological appearance was scored according to Modified Kraus' Mankin and Osteoarthritis Research Society International (OARSI) scores. Immunohistochemical analyses were carried out for type I and II collagens, MMP-1, and MMP-3. A comparison between groups and follow-up for each outcome was performed with the general linear model with Sidak correction. Histomorphometrical evaluations at 3 and 6 months demonstrated that OA lesions became significantly worse followed by Hyaff-11 treatment, whereas Chondrocytes+Hyaff-11 treatment had the best overall subjective grade. Overall raw histological scores demonstrated a significant improvement with chondro-hyaluronic acid (HA) treatment at 3 months compared with HA in cartilage repair processes. Immunohistochemical analyses displayed a strong positivity for type II collagen in the Chondrocytes+Hyaff-11group at 3 months compared with the HA group. No staining was observed in MMP-3 expression in this group at any experimental point. The use of Chondrocytes+Hyaff-11 for the treatment of early OA lesions produced, already at 3 months, a repair tissue showing better macroscopic, histological, and immunohistochemical results than those observed after Hyaff-11 treatment. Thus, the transplantation of Chondrocytes+Hyaff-11 would seem to be advocated in the very early stage of the OA disease when a precocious action is mandatory.

Arthroscopic-assisted removal of proximal tibia locking plates

We present a new technique to remove plates from the proximal tibia arthroscopic-assisted with all advantages of the minimally invasive surgery and the possibility to treat concomitant intraarticular pathologies. The initial results (n = 7) are promising with an increase of the Lysholm score in all cases studied [preop. median 78 (range 32–100), postop. median 89 (range 60–100)]. In conclusion, arthroscopic-assisted hardware removal at the proximal tibia is feasible and may provide patients with all the benefits of minimal-invasive hardware removal. The described technique can be recommended for all surgeons familiar with arthroscopic surgery.

The potential of intra-articular injection of chondrogenic-induced bone marrow stem cells to retard the progression of osteoarthritis in a sheep model

In recent years, the use of bone marrow mesenchymal stem cell (BMSC) implantation has provided an alternative treatment for osteoarthritis. The objective of this study is to determine whether or not an intra-articular injection of a single dose of autologous chondrogenic induced BMSC could retard the progressive destruction of cartilage in a surgically induced osteoarthritis in sheep. Sheep BMSCs were isolated and divided into two groups. One group was cultured in chondrogenic media containing (Ham's F12:DMEM, 1:1) FD+1% FBS+5 ng/ml TGFβ3+50 ng/ml IGF-1 (CM), and the other group was cultured in the basal media, FD+10% FBS (BM). The procedure for surgically induced osteoarthritis was performed on the donor sheep 6 weeks prior to intra-articular injection into the knee joint of a single dose of BMSC from either group, suspended in 5 ml FD at density of 2 million cells/ml. The control groups were injected with basal media, without cells. Six weeks after injection, gross evidence of retardation of cartilage destruction was seen in the osteoarthritic knee joints treated with CM as well as BM. No significant ICRS (International Cartilage Repair Society) scoring was detected between the two groups with cells. However macroscopically, meniscus repair was observed in the knee joint treated with CM. Severe osteoarthritis and meniscal injury was observed in the control group. Interestingly, histologically the CM group demonstrated good cartilage histoarchitecture, thickness and quality, comparable to normal knee joint cartilage. As a conclusion, intra-articular injection of a single dose of BMSC either chondrogenically induced or not, could retard the progression of osteoarthritis (OA) in a sheep model, but the induced cells indicated better results especially in meniscus regeneration.

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.

Cell Seeding Densities in Autologous Chondrocyte Implantation Techniques for Cartilage Repair

Cartilage repair techniques have been among the most intensively investigated treatments in orthopedics for the past decade, and several different treatment modalities are currently available. Despite the extensive research effort within this field, the generation of hyaline cartilage remains a considerable challenge. There are many parameters attendant to each of the cartilage repair techniques that can affect the amount and types of reparative tissue generated in the cartilage defect, and some of the most fundamental of these parameters have yet to be fully investigated. For procedures in which in vitro-cultured autologous chondrocytes are implanted under a periosteal or synthetic membrane cover, or seeded onto a porous membrane or scaffold, little is known about how the number of cells affects the clinical outcome. Few published clinical studies address the cell seeding density that was employed. The principal objective of this review is to provide an overview of the cell seeding densities used in cell-based treatments currently available in the clinic for cartilage repair. Select preclinical studies that have informed the use of specific cell seeding densities in the clinic are also discussed.

Fibrin-based model for cartilage regeneration: tissue maturation from in vitro to in vivo

One of the crucial points for a successful tissue-engineering approach for cartilage repair is represented by the level of in vitro maturation of the engineered tissue before implantation. The purpose of this work was to evaluate the effect of the level of in vitro maturation of engineered cartilaginous samples on the tissue quality after in vivo implantation. Samples were obtained from isolated swine articular chondrocytes embedded in fibrin glue. The cell-fibrin composites were either cultured in vitro or directly implanted in vivo for 1, 5, and 9 weeks. Other experimental samples were precultured for either 1 or 5 weeks in vitro and then implanted in vivo for 4 additional weeks. All the samples were analyzed by histology, immunohistochemistry, biochemistry, and gene expression. The results strongly suggest that the in vivo culture in this model promoted a better tissue maturation than that obtained in the in vitro condition, and that 1 week in vitro preculture resulted in the primary structuring of the engineered composites and their subsequent maturation in vivo, without affecting the cell viability and activity, while a prolonged in vitro preculture caused a cell and matrix degeneration that could not be rescued in vivo.

Surgical treatment for early osteoarthritis. Part I: cartilage repair procedures

Young patients with early osteoarthritis (OA) represent a challenging population due to a combination of high functional demands and limited treatment options. Conservative measures such as injection and physical therapy can provide short-term pain relief but are only palliative in nature. Joint replacement, a successful procedure in the older population, is controversial in younger patients, who are less satisfied and experience higher failure rates. Therefore, while traditionally not indicated for the treatment of OA, cartilage repair has become a focus of increased interest due to its potential to provide pain relief and alter the progression of degenerative disease, with the hope of delaying or obviating the need for joint replacement. This review of cartilage repair techniques will discuss currently available procedures, specifically pertaining to experiences in the setting of early OA. Level of evidence IV.

Critical-size defect induces unicompartmental osteoarthritis in a stable ovine knee

Animal models simulating osteoarthritis are frequently associated with irreversible changes in biomechanics. Although these models successfully induce osteoarthritis, results of experimental repair procedures are impaired by biomechanical problems. The aim of this study was to define the critical size of a chondral lesion to induce unicompartmental osteoarthritis in a stable joint. Sixteen sheep were randomly divided into four treatment groups. A cartilage defect (7- or 14-mm diameter) was created in the weight-bearing zone of the medial femoral condyle. The sheep were mobilized for 6 or 12 weeks. Osteoarthritis was determined by gross assessment, India ink staining, histology (Mankin score), and analysis of COMP in the serum. In the 6-week group, only minor osteoarthritis was registered for either defect size. After 12 weeks, the 14-mm defect induced minor osteoarthritis at the femoral condyle and caused significant degenerative changes at the tibial articular cartilage and the meniscus. The 7-mm defect created focal unicompartmental osteoarthritis at the medial femoral condyle and minor degenerative changes at the corresponding tibia. A 7-mm full-thickness chondral defect with a weight-bearing regimen of 12 weeks induced local osteoarthritis at the medial compartment in an otherwise stable joint as aimed.

A review of the treatment methods for cartilage defects

The purpose of this article is to provide a broad review of the literature related to the treatment of cartilage defects and degenerated cartilage in animals with some inferences to the treatment in humans. Methods range from the insertion of osteochondral tissue or cells to the application of radio frequency or insertion of scaffolds and growth factors alone or in combination. Debridement, microfracture, radio frequency, and chondrocyte implantation are all methods normally utilized when treating smaller articular cartilage defects. Scaffolds and mosaicplasty are examples of methods to treat larger defects. This review will cover all major treatment methods currently used to treat articular cartilage defects.

Evolution and Current Role of Autologous Chondrocyte Implantation for Treatment of Articular Cartilage Defects in the Football (Soccer) Player

BACKGROUND

Autologous chondrocyte implantation (ACI) continues to technically evolve, but how the technical innovations affect the ability to participate in high-impact sports such as football is unknown.

METHODS

Clinical studies describing athletes treated with first-, second-, or third-generation ACI techniques were reviewed. The technical developments of ACI were evaluated, and the results in athletes and specifically football (soccer) players were analyzed.

RESULTS

Football players reported 72% good to excellent results with significant overall improvement of knee function and activity scores. Return to football was 83% in competitive players but lower in recreational players. Eighty percent of players returned to the same competitive level after ACI, and 87% to 100% maintained their ability to play sports at 5 years postoperatively. Return to sport was better for younger, competitive players with shorter intervals between injury and ACI. New developments of the surgical technique and postoperative rehabilitation were able to reduce the limitations associated with first-generation ACI including invasiveness, graft hypertrophy, and particularly long postoperative rehabilitation. This allowed for faster return to sports like football without compromising the ability for continued competition over time.

CONCLUSION

Articular cartilage repair in football players often allows for successful return to this high-impact sport with excellent durability. The continued evolution of this technique has improved initial shortcomings with important implications for both the professional and recreational athlete.

Evaluation of magnetic resonance imaging and clinical outcome after tissue-engineered cartilage implantation: prospective 6-year follow-up study

BACKGROUND

Autologous chondrocyte implantation (ACI) is an important procedure when repairing cartilage defects of the knee. We previously reported several basic studies on tissue-engineered cartilage, and conducted a multicenter clinical study in 2009. In this clinical study, we evaluated the patients' clinical scores and MRI findings before and after tissue-engineered cartilage implantation, and compared the data obtained at 1 year and approximately 6 years post-implantation.

METHODS

Fourteen patients who underwent implantation of tissue-engineered cartilage to repair cartilage defects of the knee were evaluated. Tissue-engineered cartilage was produced by culturing autologous chondrocytes three dimensionally in atelocollagen gel. The patients were evaluated clinically using the Lysholm score, and the original knee-function score at pre-implantation and at 1 year and approximately 6 years post-implantation. MRI scans were obtained at the same observation periods. A modified magnetic resonance observation of cartilage repair tissue (MOCART) system was used to quantify clinical efficacy based on the MRI findings.

RESULTS

In approximately 6 years of follow-up, none of the 14 patients reported any subjective symptoms of concern. The mean Lysholm score and the original knee-function score (63.0 ± 10.1, 59.9 ± 5.7) significantly improved at 1 year after implantation (86.4 ± 11.8, 94.1 ± 9.2), and were maintained until 6 years after implantation (89.8 ± 6.2, 89.9 ± 11.2), although some patients showed deterioration of Lysholm and original knee scores between 1 year post-implantation and the final follow-up. The mean MOCART score was 13.2 ± 12.0 pre-implantation, and 62.5 ± 24.7 at 1 year and 70.7 ± 22.7 at approximately 6 years post-implantation. The MOCART scores at 1 year and 6 years were significantly higher than the pre-implantation score, but there was no significant difference between the scores at 1 and 6 years, indicating that the MRI results at 1 year after implantation were maintained for the next 5 years.

CONCLUSIONS

The clinical scores and MRI findings after implantation of tissue-engineered cartilage were improved at 1 year after implantation and were maintained until 6 years after implantation.

The incidence and clinical relevance of graft hypertrophy after matrix-based autologous chondrocyte implantation

BACKGROUND

Graft hypertrophy is the most common complication of periosteal autologous chondrocyte implantation (p-ACI).

PURPOSE

The aim of this prospective study was to analyze the development, the incidence rate, and the persistence of graft hypertrophy after matrix-based autologous chondrocyte implantation (mb-ACI) in the knee joint within a 2-year postoperative course.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 2004 and 2007, a total of 41 patients with 44 isolated cartilage defects of the knee were treated with the mb-ACI technique. The mean age of the patients was 35.8 years (standard deviation [SD], 11.3 years), and the mean body mass index was 25.9 (SD, 4.2; range, 19-35.3). The cartilage defects were arthroscopically classified as Outerbridge grades III and IV. The mean area of the cartilage defect measured 6.14 cm(2) (SD, 2.3 cm(2)). Postoperative clinical and magnetic resonance imaging (MRI) examinations were conducted at 3, 6, 12, and 24 months to analyze the incidence and course of the graft.

RESULTS

Graft hypertrophy developed in 25% of the patients treated with mb-ACI within a postoperative course of 1 year; 16% of the patients developed hypertrophy grade 2, and 9% developed hypertrophy grade 1. Graft hypertrophy occurred primarily in the first 12 months and regressed in most cases within 2 years. The International Knee Documentation Committee (IKDC) and visual analog scale (VAS) scores improved during the postoperative follow-up time of 2 years. There was no difference between the clinical results regarding the IKDC and VAS pain scores and the presence of graft hypertrophy.

CONCLUSION

The mb-ACI technique does not lead to graft hypertrophy requiring treatment as opposed to classic p-ACI. The frequency of occurrence of graft hypertrophy after p-ACI and mb-ACI is comparable. Graft hypertrophy can be considered as a temporary excessive growth of regenerative cartilage tissue rather than a true graft hypertrophy. It is therefore usually not a persistent or systematic complication in the treatment of circumscribed cartilage defects with mb-ACI.

Prone position for minimal invasive or all-arthroscopic autologous chondrocyte implantation at the patella

Full size retropatellar cartilage lesions are troublesome conditions to treat and an autologous chondrocyte implantation with or without matrix or scaffold in supine position is difficult. Usually, it is necessary to perform a large arthrotomy to evert the patella in order to get sufficient access to the retropatellar cartilage defect. The procedure is associated with a significant parapatellar soft tissue trauma to the patient. This technical note introcudes a minimal invasive approach with the patient in prone position using an all-arthroscopic or mini-open technique to treat retropatellar full size articular cartilage lesions of the patella.

MR imaging assessment of articular cartilage repair procedures

Because articular cartilage is avascular and has no intrinsic capacity to heal itself, physical damage to cartilage poses a serious clinical problem for orthopedic surgeons and rheumatologists. No medication exists to treat or reconstitute physical defects in articular cartilage, and pharmacotherapy is limited to pain control. Developments in the field of articular cartilage repair include microfracture, osteochondral autografting, osteochondral allografting, repair with synthetic resorbable plugs, and autologous chondrocyte implantation. MR imaging techniques have the potential to allow in vivo monitoring of the collagen and proteoglycan content of cartilage repair tissue and may provide useful additional metrics of cartilage repair tissue quality.

Comparative study of the areas of osteochondral defects produced in the femoral condyles of rabbits treated with gel of sugarcane biopolymer

PURPOSE: To measure the healed areas of osteochondral defects produced in femoral condyles of rabbits filled with biopolymer sugar cane gel and to compare these with those of the control group at 90, 120 and 180 days. METHODS: A study was made of 16 New Zealand rabbits, 6 and 7 months old, weighing between 2 and 2.5 kg. Defects of 3.2 x 4 mm were made, with trephine, in the femoral condyles of the right and left knees. As to the study group defects of the medial and lateral condyles of the right knee were used which were filled with Biopolymer Sugar Cane Gel; as to the Control Group defects of the medial and lateral condyles of the left t knees were used which were left open for natural healing. The defects were analyzed at 90, 120 and 180 days after surgery. After euthanasia, the knees were removed and fixed in Bouin's solution for later digital photographic documentation with a digital camera. The areas healed were measured in both the study and control groups using the images obtained from an Image-J® program. Statistical analysis was conducted using the non-parametric Mann-Whitney test. RESULTS: There were no significant differences between the means of the healed areas in the study and control groups at 90, 120 and 180 days after surgery. CONCLUSION: The dimension of the healed areas of the defects treated with the biopolymer sugar-cane gel in the study group was similar to those of the control group, which healed naturally.

The healing effect of bioglue in articular cartilage defect of femoral condyle in experimental rabbit model

Background

The full-thickness articular cartilage defects of knee have a poor healing capacity that may progress to osteoarthritis and need a knee replacement. This study determines the healing effect of bioglue in fullthickness articular cartilage defect of femoral condyle in rabbit.

Methods

Forty-eight male rabbits were randomly divided into four equal groups. In group A, 4 mm articular cartilage defects were created in the right and left medial femoral condyles. Then a graft from xiphoid cartilage was transferred into the defect together with a designed bioglue and the knees were closed. In group B, an articular cartilage defect was created identical to group A, but the defect size was 6 mm. In group C, 4 and 6 mm articular cartilage defects were created in the right and left medial femoral condyles respectively. The graft was transferred into the defect and the knees were stitched. In group D, articular cartilage defects were created similar to group C, just filled with bioglue and closed. The rabbits were euthanized and subgroups were defined as A1, B1, C1 and D1 after 30 days and A2, B2, C2 and D2 after 60 days. The cartilages were macroscopically and histologically investigated for any changes.

Results

Microscopic and macroscopic investigations showed that bioglue had a significant healing effect in the femoral condyle.

Conclusion

Addition of bioglue can effectively promote the healing of articular cartilage defects.

Repair of focal cartilage defects with scaffold-assisted autologous chondrocyte grafts: clinical and biomechanical results 48 months after transplantation

BACKGROUND

Scaffold-assisted autologous chondrocyte implantation is a clinically effective procedure for cartilage repair, but biomechanical evaluations are still missing.

PURPOSE

This study was conducted to assess the clinical efficacy, including biomechanical analyses, of BioSeed-C treatment for traumatic and degenerative cartilage defects of the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors evaluated the midterm clinical and biomechanical outcome of BioSeed-C, a cell-based fibrin-polymer graft for the treatment of cartilage defects. Clinical outcome at 4-year follow-up was assessed in 52 patients with full-thickness cartilage defects, International Cartilage Repair Society (ICRS) stage III and IV. Clinical scoring was performed preoperatively and 48 months after implantation using the Lysholm score, the International Knee Documentation Committee (IKDC) score, the ICRS score, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Noyes score. Cartilage regeneration was assessed by magnetic resonance imaging (MRI) using the Henderson-Kreuz score. Biomechanical evaluation was performed by isokinetic strength measurements, comparing healthy and operated knee of each patient.

RESULTS

Clinical evaluation showed significant improvement in the Lysholm (from 51.8 preoperatively to 80.7 at 48 months postoperatively), IKDC (from 47.5 to 71.5), ICRS (from 3.8 to 2.0), KOOS (subcategory pain from 62 to 78, symptoms from 68 to 76, activities of daily living from 68 to 85, sports from 19 to 55, and quality of life from 30 to 55), and Noyes (from 31 to 59) scores (P ≤ .001) 48 months after implantation of BioSeed-C compared with the preoperative situation. The MRI evaluations showed moderate to complete defect filling in 43 of 44 treated patients. Two patients without improvement in the clinical and MRI scores received a total knee endoprosthesis after 4 years. Isokinetic evaluation showed significantly reduced maximum strength capacities for knee flexion and extension at the operated knee compared with the healthy knee (P < .05).

CONCLUSION

The clinical outcomes 4 years after graft implantation are good despite a persisting strength deficit. Implanting BioSeed-C is a promising treatment option for cartilage defects of the knee. More emphasis should be put on the rehabilitation of muscular strength.

Failures, re-operations, and complications after autologous chondrocyte implantation--a systematic review

OBJECTIVE

To determine and compare failure, re-operation, and complication rates of all generations and techniques of autologous chondrocyte implantation (ACI).

METHODS

A systematic review of multiple medical databases was performed according to PRISMA guidelines. Levels I-IV evidence were included. Generations of ACI and complications after ACI were explicitly defined. All subject and defect demographic data were analyzed. Modified Coleman Methodology Scores (MCMSs) were calculated for all studies.

RESULTS

82 studies were identified for inclusion (5276 subjects were analyzed; 6080 defects). Ninety percent of the studies in this review were rated poor according to the MCMS. There were 305 failures overall (5.8% subjects; mean time to failure 22 months). Failure rate was highest with periosteal ACI (PACI). Failure rates after PACI, collagen-membrane cover ACI (CACI), second generation, and all-arthroscopic, second-generation ACI were 7.7%, 1.5%, 3.3%, and 0.83%, respectively. The failure rate of arthrotomy-based ACI was 6.1% vs 0.83% for all-arthroscopic ACI. Overall rate of re-operation was 33%. Re-operation rate after PACI, CACI, and second-generation ACI was 36%, 40%, and 18%, respectively. However, upon exclusion of planned second-look arthroscopy, re-operation rate was highest after PACI. Unplanned re-operation rates after PACI, CACI, second-generation, and all-arthroscopic second-generation ACI were 27%, 5%, 5%, and 1.4%, respectively. Low numbers of patients undergoing third-generation ACI precluded comparative analysis of this group.

CONCLUSIONS

Failure rate after all ACI generations is low (1.5-7.7%). Failure rate is highest with PACI, and lower with CACI and second-generation techniques. One out of three ACI patients underwent a re-operation. Unplanned re-operations are seen most often following PACI. Hypertrophy and delamination is most commonly seen after PACI. Arthrofibrosis is most commonly seen after arthrotomy-based ACI. Use of a collagen-membrane cover, second-generation techniques, and all-arthroscopic, second-generation approaches have reduced the failure, complication, and re-operation rate after ACI.

Radiological evaluation of cartilage after microfracture treatment: a long-term follow-up study

INTRODUCTION

Recent literature revealed good short-term results after microfracturing (MFX) of isolated focal cartilage defects in the knee joint. Study purpose was a long-term evaluation of patients who received MFX through a multimodal approach, correlating clinical scores and morphological pre- and postoperative MRI-scans.

MATERIALS AND METHODS

Between 2000 and 2007 158 patients were treated with MFX for focal femoral or tibial defects at our department. Patients with instabilities, secondary surgical intervention, patellofemoral lesions, a plica mediopatellaris or more than one cartilage defect site and age >55 were excluded. 15 patients were included. Minimum postoperative follow-up (FU) was 18 months (18-78 m). Mean age at surgery was 45 years (27-54), mean FU-interval 48 months (18-78 m). Male to female ratio was 9:6. For clinical assessment the Knee Osteoarthritis Ou tcome Score (KOOS) and Lysholm Score were used, radiological evaluation was performed with radiographs and 3Tesla-MRI.

RESULTS

Clinical knee function was rated good to excellent in 1 patient, fair in 2 and poor in 10 patients. 2/15 patients received full knee replacement due to insufficient cartilage repair through MFX during FU period. Evaluation of pre- and postoperative MRI showed good cartilage repair tissue in 1 (7.7%), moderate repair in 2 (15.4%) and poor fill in 10 patients (76.9%). In these 10 patients the defect size increased. Average defect size preoperatively was 187 mm(2) (range 12-800 mm(2)) and postoperatively 294 mm(2) (40-800 mm(2)). The KOOS-Pain averaged 60 (39-94), KOOS-Symptoms 60.6 (21-100), KOOS-ADL 69 (21-91), KOOS-Sports 35.7 (5-60) and KOOS-QUL 37.2 (6-81). The average Lysholm Score was 73.9 (58-94). 10 patients showed a varus leg axis deviation (Ø 5.9°), 3 had a neutral alignment. The alignment correlated positively with KOOS and especially with the Lysholm Score.

CONCLUSION

Our study demonstrated that MFX as a treatment option for cartilage defect in the knee did not show the anticipated clinical and radiological long-term results. In 12 of 15 patients the cartilage defect size had increased after MFX, in 2 patients indicating full-knee replacement. Especially those with a leg malalignment >5° in varus were more prone to suffer from an increase in defect size. In our cohort the clinical scores correlated with the radiological findings.

Autologous chondrocyte implantation (ACI) for the treatment of large and complex cartilage lesions of the knee

Background

Complex cartilage lesions of the knee including large cartilage defects, kissing lesions, and osteoarthritis (OA) represent a common problem in orthopaedic surgery and a challenging task for the orthopaedic surgeon. As there is only limited data, we performed a prospective clinical study to investigate the benefit of autologous chondrocyte implantation (ACI) for this demanding patient population.

Methods

Fifty-one patients displaying at least one of the criteria were included in the present retrospective study: (1.) defect size larger than 10 cm²; (2.) multiple lesions; (3.) kissing lesions, cartilage lesions Outerbridge grade III-IV, and/or (4.) mild/moderate osteoarthritis (OA). For outcome measurements, the International Cartilage Society's International Knee Documentation Committee's (IKDC) questionnaire, as well as the Cincinnati, Tegner, Lysholm and Noyes scores were used. Radiographic evaluation for OA was done using the Kellgren score.

Results and Discussion

Patient's age was 36 years (13-61), defects size 7.25 (3-17.5) cm², previous surgical procedures 1.94 (0-8), and follow-up 30 (12-63) months. Instruments for outcome measurement indicated significant improvement in activity, working ability, and sports. Mean ICRS grade improved from 3.8 preoperatively to grade 3 postoperatively, Tegner grade 1.4 enhanced to grade 3.39. The Cincinnati score enhanced from 25.65 to 66.33, the Lysholm score from 33.26 to 64.68, the Larson score from 43.59 to 79.31, and Noyes score from 12.5 to 46.67, representing an improvement from Cincinnati grade 3.65 to grade 2.1. Lysholm grade 4 improved to grade 3.33, and Larson grade 3.96 to 2.78 (Table 1), (p < 0.001). Patients with kissing cartilage lesions had similar results as patients with single cartilage lesions.

Conclusion

Our results suggest that ACI provides mid-term results in patients with complex cartilage lesions of the knee. If long term results will confirm our findings, ACI may be a considered as a valuable tool for the treatment of complex cartilage lesions of the knee.

Therapeutic strategy of third-generation autologous chondrocyte implantation for osteoarthritis

BACKGROUND

Autologous chondrocyte implantation (ACI) is considered a promising choice for the treatment of cartilage defects. However, the application of ACI to osteoarthritic patients is, in general, contraindicated. The purpose of this study is to evaluate the efficiency of three-dimensionally structured ACI (3D-ACI; CaReS) in a rat model of knee osteoarthritis (OA).

METHODS

OA-like degenerative changes in the articular cartilage were created by transecting the anterior cruciate ligament (ACLT) in athymic nude rats. Two weeks later, CaReS was transplanted at the cartilage injury sites created by micro-drilling in the patella groove (Chondrocyte-implanted (CI) group: CaReS collagen with human chondrocytes; Collagen group: CaReS collagen without cells; and Sham group: sham operation; n = 15/group).

RESULTS

Reverse Transcription Polymerase Chain Reaction (RT-PCR) analysis demonstrated the expression of human-specific type 2 collagen and Sry-type high-mobility-group box 9 (SOX9) in the CI group-not in the other groups-throughout the study period. Double immunohistochemistry for human-specific type 2 collagen and human leukocyte antigen-abacavir (HLA-ABC) at week 4 showed positive staining in the CI group only. Macroscopic assessment showed better repair at the cartilage defect sites in the CI group, compared to the other groups. Histological assessment with toluidine blue staining showed that the thickness of the articular cartilage and semi-quantitative histological scores were higher in the CI group than in the other groups up to week 20.

CONCLUSIONS

We demonstrate, for the first time, that 3D-ACI is effective in repairing cartilage defects in a rat model of ACLT-induced OA.

Clinical and magnetic resonance imaging-based outcomes to 5 years after matrix-induced autologous chondrocyte implantation to address articular cartilage defects in the knee

BACKGROUND

The availability remains limited of midterm clinical and radiologic results into matrix-induced autologous chondrocyte implantation (MACI). Outcomes are required to validate the efficacy of MACI as a suitable surgical treatment option for articular cartilage defects in the knee.

HYPOTHESIS

A significant improvement in clinical and magnetic resonance imaging-based (MRI-based) outcomes after MACI will exist throughout the postoperative timeline to 5 years after surgery. Furthermore, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with patient and graft outcome, whereas a significant correlation will exist between clinical and MRI-based outcomes at 5 years after surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective evaluation was undertaken to assess clinical and MRI-based outcomes to 5 years in 41 patients (53 grafts) after MACI to the knee. After MACI surgery and a 12-week structured rehabilitation program, patients underwent clinical assessments (Knee injury and Osteoarthritis Outcome Score, SF-36, 6-minute walk test, knee range of motion) and MRI assessments at 3, 12, and 24 months, as well as 5 years after surgery. The MRI evaluation assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score.

RESULTS

A significant improvement (P < .05) was demonstrated for all Knee injury and Osteoarthritis Outcome Score and SF-36 subscales over the postoperative timeline, as well as the 6-minute walk test and active knee extension. A significant improvement (P < .0001) was observed for the MRI composite score, as well as several individual graft scoring parameters. At 5 years after surgery, 67% of MACI grafts demonstrated complete infill, whereas 89% demonstrated good to excellent filling of the chondral defect. Patient demographics, cartilage defect parameters, and injury/surgery history demonstrated no significant pertinent correlations with clinical or MRI-based outcomes at 5 years, and no significant correlations existed between clinical and MRI-based outcome measures. At 5 years after surgery, 98% of patients were satisfied with the ability of MACI surgery to relieve knee pain; 86%, with improvement in their ability to perform normal daily tasks; and 73%, with their ability to participate in sport 5 years after MACI.

CONCLUSION

These results suggest that MACI provides a suitable midterm treatment option for articular cartilage defects in the knee. Long-term follow-up is essential to confirm whether the repair tissue has the durability required to maintain long-term patient quality of life.

We do not have evidence based methods for the treatment of cartilage defects in the knee

PURPOSE

The aim of this study was to perform a systematic review of studies concerning current treatment of chondral defects of the knee.

METHODS

The relevance for evidence based data and for successful surgical treatment of cartilage defects was evaluated. From 56,098 evaluated studies, 133 studies could be further pursued. These supplied data concerning microfracturing, the osteochondral autograft transplantation system (OATS), the autologous chondrocyte implantation (ACI) and the matrix induced chondrocyte implantation (MACI). The modified Coleman Methodical Score (CMS) and the Level of Evidence (LOE) were applied to evaluate the quality.

RESULTS

In these studies, a total of 6,920 patients were reviewed with a median of 32 patients per study and a mean follow-up of 24 months. The mean CMS was 58 of 100 points. No study reached 100 points in the CMS. Three studies reached a level above 90. Ten studies were Level I, five studies reached Level II. Seven studies reached Level III, 111 studies Level IV. MRI scans to verify the clinical data were used by only 72 studies. The means in the modified CMS were for the different procedures as follows: ACI 58 points, MACI 57 points, microfracturing 68 points and OATS 50 points. 24 studies applied the Lysholm Score (LS) for clinical evaluation of cartilage surgery. All operative procedures yielded comparable improvements of the LS (n.s.) meaning that no operative procedure proved superior.

CONCLUSION

As the majority of studies evaluated by this review is insufficient for EBM purposes more coherent studies with LOE of I or II are needed. Co-relating the systems of CMS and LOE and validating the applied scores seems desirable.

ICRS Recommendation Document: Patient-Reported Outcome Instruments for Use in Patients with Articular Cartilage Defects

OBJECTIVE

The purpose of this article is to describe and recommend patient-reported outcome instruments for use in patients with articular cartilage lesions undergoing cartilage repair interventions.

METHODS

Nonsystematic literature search identifying measures addressing pain and function evaluated for validity and psychometric properties in patients with articular cartilage lesions.

RESULTS

The knee-specific instruments, titled the International Knee Documentation Committee Subjective Knee Form and the Knee injury and Osteoarthritis and Outcome Score, both fulfill the basic requirements for reliability, validity, and responsiveness in cartilage repair patients. A major difference between them is that the former results in a single score and the latter results in 5 subscores. A single score is preferred for simplicity's sake, whereas subscores allow for evaluation of separate constructs at all levels according to the International Classification of Functioning.

CONCLUSIONS

Because there is no obvious superiority of either instrument at this time, both outcome measures are recommended for use in cartilage repair. Rescaling of the Lysholm Scoring Scale has been suggested, and confirmatory longitudinal studies are needed prior to recommending this scale for use in cartilage repair. Inclusion of a generic measure is feasible in cartilage repair studies and allows analysis of health-related quality of life and health economic outcomes. The Marx or Tegner Activity Rating Scales are feasible and have been evaluated in patients with knee injuries. However, activity measures require age and sex adjustment, and data are lacking in people with cartilage repair.

Radiological Assessment of Accelerated versus Traditional Approaches to Postoperative Rehabilitation following Matrix-Induced Autologous Chondrocyte Implantation

OBJECTIVE

To assess the safety and efficacy of accelerated compared with traditional postoperative weightbearing (WB) rehabilitation following matrix-induced autologous chondrocyte implantation (MACI) of the knee, using MRI.

METHODS

A randomized controlled study design was used to assess MRI-based outcomes of MACI grafts in 70 patients (45 men, 25 women) who underwent MACI to the medial or lateral femoral condyle, in combination with either traditional or accelerated approaches to postoperative WB rehabilitation. High-resolution MRI was undertaken and assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score at 3, 12, and 24 months postsurgery. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated.

RESULTS

Both groups significantly improved (P < 0.05) in the MRI composite score and pertinent descriptors of graft repair throughout the postoperative period until 24 months postsurgery. There were no differences (P > 0.05) observed between the 2 groups. Patient age, body mass index, chondral defect size, and duration of preoperative symptoms were significantly correlated (P < 0.05) with several MRI-based outcomes at 24 months, whereas there were no significant pertinent correlations (P > 0.05) observed between clinical and MRI-based outcomes.

CONCLUSION

The accelerated WB approach was not detrimental to graft development at any stage throughout the postoperative assessment timeline from baseline to 24 months postsurgery and may potentially accelerate patient return to normal function, while reducing postoperative muscle loss, intra-articular adhesions, and associated gait abnormalities.

Mesenchymal Progenitor Cells and Their Orthopedic Applications: Forging a Path towards Clinical Trials

Mesenchymal progenitor cells (MPCs) are nonhematopoietic multipotent cells capable of differentiating into mesenchymal and nonmesenchymal lineages. While they can be isolated from various tissues, MPCs isolated from the bone marrow are best characterized. These cells represent a subset of bone marrow stromal cells (BMSCs) which, in addition to their differentiation potential, are critical in supporting proliferation and differentiation of hematopoietic cells. They are of clinical interest because they can be easily isolated from bone marrow aspirates and expanded in vitro with minimal donor site morbidity. The BMSCs are also capable of altering disease pathophysiology by secreting modulating factors in a paracrine manner. Thus, engineering such cells to maximize therapeutic potential has been the focus of cell/gene therapy to date. Here, we discuss the path towards the development of clinical trials utilizing BMSCs for orthopaedic applications. Specifically, we will review the use of BMSCs in repairing critical-sized defects, fracture nonunions, cartilage and tendon injuries, as well as in metabolic bone diseases and osteonecrosis. A review of www.ClinicalTrials.gov of the United States National Institute of Health was performed, and ongoing clinical trials will be discussed in addition to the sentinel preclinical studies that paved the way for human investigations.

Autologous chondrocyte implantation for treatment of focal cartilage defects in patients age 40 years and older: A matched-pair analysis with 2-year follow-up

BACKGROUND

Autologous chondrocyte implantation (ACI) is an accepted surgical treatment in patients with isolated cartilage defects of the knee. Age has been considered as a limiting factor and the technique has not been recommended in patients older than 40 to 50 years. Nevertheless, some more recent studies report satisfying clinical results in middle-aged patients.

HYPOTHESIS

Analogous to the microfracture technique, age over 40 years is associated with inferior clinical outcome after ACI.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Thirty-seven patients with an average age of 47.8 years (group 1) were matched with 37 patients with an average age of 31 years (group 2). Both groups underwent ACI for treatment of isolated cartilage defects of the knee. All patients were enrolled prospectively and followed for a period of 24 months using International Knee Documentation Committee (IKDC), Lysholm scale, Cincinnati sports scale, and Tegner activity evaluation instruments.

RESULTS

Statistical analysis revealed a significant increase in function after ACI in both groups as early as 6 months after surgery until the end of the study period. There was only a slight tendency for better clinical outcome in younger patients (IKDC at 24 months: group 1, 72.2 ± 15.8 [standard deviation]; group 2: 76.1 ± 14.1; P = .261; Lysholm at 24 months: group 1: 80.42 ± 15.37; group 2: 80.65 ± 12.01), no statistical significant differences were found between patients of group 1 and group 2 at any of the time points investigated.

CONCLUSION

In contrast to other cartilage repair techniques, patients 40 years and older do not have an inferior outcome up to 24 months after ACI for isolated cartilage defects when compared with younger patients.

Mid-term results of Autologous Matrix-Induced Chondrogenesis for treatment of focal cartilage defects in the knee

Articular cartilage defects heal poorly. Autologous Matrix-Induced Chondrogenesis (AMIC) is an innovative treatment for localized full-thickness cartilage defects combining the well-known microfracturing with collagen scaffold and fibrin glue. The purpose of this prospective study was to evaluate the medium-term results of this enhanced microfracture technique for the treatment of chondral lesions of the knee. Thirty-two chondral lesions in 27 patients were treated with AMIC. Within the context of clinical follow-up, these patients were evaluated for up to 5 years after the intervention. Five different scores (Meyer score, Tegner score, Lysholm score, ICRS score, Cincinnati score) as well as radiographs were used for outcome analysis. Articular resurfacing was assessed by magnetic resonance imaging (MRI). The average age of patients (11 females, 16 males; mean body mass index 26, range 20-32) was 37 years (range 16-50 years). The mean defect size of the chondral lesions was 4.2 cm(2) (range 1.3-8.8 cm(2)). All defects were classified as grade IV according to the Outerbridge classification. The follow-up period was between 24 and 62 months with a mean of 37 months. Twenty out of 23 individuals (87%) questioned were subjectively highly satisfied with the results after surgery. Significant improvement (P < 0.05) of all scores was observed as early as 12 months after AMIC, and further increased values were notable up to 24 months postoperatively. MRI analysis showed moderate to complete filling with a normal to incidentally hyperintense signal in most cases. Results did not show a clinical impact of patient's age at the time of operation, body mass index and number of previous operations (n.s.). In contrast, males showed significant higher values in the ICRS score compared to their female counterparts. AMIC is an effective and safe method of treating symptomatic full-thickness chondral defects of the knee in appropriately selected cases. However, further studies with long-term follow-up are needed to determine whether the grafted area will maintain structural and functional integrity over time.

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.

Chondrogenesis of human mesenchymal stem cells by local transforming growth factor-beta delivery in a biphasic resorbable carrier

Little is known about the potential of growth factor-augmented biphasic implants composed of a gel and a solid scaffold to enhance chondrogenesis of mesenchymal stem cells (MSCs). We analyzed whether a collagen type I/III carrier and fibrin glue (FG) combined to a biphasic construct support in vitro chondrogenesis of MSCs and allow for local release of bioactive transforming growth factor-beta1 (TGF-beta1). Further, a possible advantage of partial autologous fibrin glue (PAF) over commercial FG was assessed. Collagen carriers seeded with 5 x 10(5) human MSCs with or without FG, PAF, or TGF-beta1-upgraded FG were cultured for 6 weeks in chondrogenic medium with or without TGF-beta1. Pellets with or without FG/PAF served as controls. FG and collagen carriers allowed strong upregulation of COL2A1, AGC, and COL10A1 mRNA, deposition of collagen-type II, and mediated a significantly higher proteoglycan content compared with biomaterial-free pellets. Collagen-carrier groups contained significantly more proteoglycan than FG and PAF pellets, whereas biphasic PAF-carrier constructs were inferior to FG-carrier constructs. Upgrading of biphasic FG-carrier constructs with 50 ng TGF-beta1/construct mediated chondrogenesis as successfully as supply of TGF-beta1 via the medium. In conclusion, the biphasic carrier constructs showed a high biofunctionality by continuous form stability with improved chondrogenesis and long-term local supply of bioactive TGF-beta1 which may be useful to enhance matrix-assisted repair strategies for damaged cartilage.

Gene expression profiling of primary human articular chondrocytes in high-density micromasses reveals patterns of recovery, maintenance, re- and dedifferentiation

The high-density micromass culture has been widely applied to study chondrocyte cell physiology and pathophysiological mechanisms. Since an integrated image has not been established so far, we analyzed the phenotypic alterations of human articular chondrocytes in this model on the broad molecular level. Freshly isolated chondrocytes were assembled as micromasses and maintained up to 6 weeks in medium containing human serum. Formation of cartilaginous extracellular matrix (ECM) was evaluated by histological and immunohistochemical staining. At 0, 3 and 6 weeks, chondrocyte micromasses were subjected to gene expression analysis using oligonucleotide microarrays and real-time RT-PCR. Micromasses developed a cartilaginous ECM rich in proteoglycans and type II collagen. On gene expression level, time-dependent expression patterns was observed. The induction of genes associated with cartilage-specific ECM (COL2A1 and COL11A1) and developmental signaling (GDF5, GDF10, ID1, ID4 and FGFR1-3) indicated redifferentiation within the first 3 weeks. The repression of genes related to stress response (HSPA1A and HSPA4), apoptotic events (HYOU1, NFKBIA and TRAF1), and degradation (MMP1, MMP10 and MMP12) suggested a recovery of chondrocytes. Constant expression of other chondrogenic (ACAN, FN1 and MGP) and hypertrophic markers (COL10A1, ALPL, PTHR1 and PTHR2) indicated a pattern of phenotypic maintenance. Simultaneously, the expression of chondrogenic growth (BMP6, TGFA, FGF1 and FGF2) and transcription factors (SOX9, EGR1, HES1 and TGIF1), and other cartilage ECM-related genes (COMP and PRG4) was consistently repressed and expression of collagens related to dedifferentiation (COL1A1 and COL3A1) was steadily induced indicating a progressing loss of cartilage phenotype. Likewise, a steady increase of genes associated with proliferation (GAS6, SERPINF1, VEGFB and VEGFC) and apoptosis (DRAM, DPAK1, HSPB, GPX1, NGFRAP1 and TIA1) was observed. Sequence and interplay of identified expression patterns suggest that chondrocyte micromass cultures maintain a differentiated phenotype up to 3 weeks in vitro and might be useful for studying chondrocyte biology, pathophysiology and differentiation. Cultivation longer than 6 weeks leads to progressing dedifferentiation of chondrocytes that should be considered on long-term evaluations.

A cell-free collagen type I device for the treatment of focal cartilage defects

The purpose of this study was to evaluate the potential value of a cell-free collagen type I gel plug for the treatment of focal cartilage defects. Cellular migration and proliferation was addressed in vitro, and the formation of repair tissue in a nude mouse-based defect model. A cell-free plug made of collagen type I was placed in the center of an incubation plate. Surrounding space was filled with a collagen type I gel (Arthro Kinetics, Esslingen, Germany) seeded with 2 x 10(5) human articular chondrocytes/mL gel. After cultivation for up to 6 weeks in vitro, samples were subject to histological and immunohistochemical staining and gene expression analysis. Subsequently, chondral defects of human osteochondral blocks were treated with the plug, and specimens were cultivated subcutaneously in nude mice for 6 weeks. The repair tissue was evaluated macroscopically, and collagen type II production was investigated immunohistochemically. In vitro, morphology of immigrated cells did not show any differences, as did collagen type II gene expression. After 4 weeks, the plug was homogeneously inhabited. After 6 weeks of cultivation in nude mice, collagen gel plug treatment led to a macroscopically excellent repair tissue. Histological staining revealed a tight bonding, and the collagen gel plug started to be remodeled. We conclude that the novel collagen gel plug device offers an environment favorable for the migration of articular chondrocytes and leads to a good-quality repair tissue in the nude mouse model. The arthroscopic transplantation of a collagen gel plug may be one option in the treatment of focal cartilage defects.

A novel nano-composite multi-layered biomaterial for treatment of osteochondral lesions: technique note and an early stability pilot clinical trial

INTRODUCTION

Osteochondral articular defects are a key concern in orthopaedic surgery. Current surgical techniques to repair osteochondral defects lead to poor subchondral bone regeneration and fibrocartilage formation, which is often associated with joint pain and stiffness. The objective of this pilot clinical study is to evaluate the performance and the intrinsic stability of a newly developed biomimetic osteochondral scaffold and to test the safety and the feasibility of the surgical procedure.

METHODS

A gradient composite osteochondral scaffold based on type I collagen-hydroxyapatite was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. Thirteen patients (15 defect sites) were treated with scaffold implantation from January 2007 to July 2007: four at the medial femoral condyle, two at the lateral femoral condyles, five at the patellas and four at the trochleas. The mean size of the defects was 2.8 cm(2) (range: 1.5-5.9 cm(2)). All patients were followed up prospectively. High-resolution magnetic resonance imaging (MRI) was used to determine "the early postoperative adherence rate" at 4-5 weeks and 25-26 weeks after scaffold implantation. Moreover, the magnetic resonance observation of cartilage repair tissue (MOCART) score was performed on every MRI. Two second-looks were performed at 6 months; cartilage repair was assessed using the International Cartilage Repair Society (ICRS) visual scoring system and histological and immunohistochemical analysis of the two biopsies was carried out.

RESULTS

A completely attached graft and repair tissue were found in 13 of 15 lesions (86.7%). A partial detachment was observed in two patients (13.3%). No detached grafts were found. Complete filling of the cartilage defect and congruency of the articular surface were seen in 10 lesions (66.7%) with MRI evaluation at 6 months. The complete integration of the grafted cartilage was detected in eight lesions (53.3%). Subchondral bone changes (oedema or sclerosis) were found in eight defects (53.3%). Statistical analysis showed a significant improvement in the International Knee Documentation Committee (IKDC) subjective and objective scores from preoperative to 6 months' follow-up (p<0.0005). Visual scoring of the repaired tissue at second-look revealed a normal repair score in one case and a near-normal repair score in the other case. Histological analysis showed the formation of subchondral bone without the presence of biomaterial. The cartilage repair tissue appeared to be engaged in an ongoing maturation process.

CONCLUSIONS

The technique is safe and MRI evaluation at short-term follow-up has demonstrated good stability of the scaffold without any other fixation device. The preliminary clinical results at short-term follow-up are encouraging. A clinical and MRI study with longer follow-up and randomised studies will be done to confirm the high potential of this novel osteochondral scaffold.

Articular Cartilage Injury in Athletes

Articular cartilage lesions in the athletic population are observed with increasing frequency and, due to limited intrinsic healing capacity, can lead to progressive pain and functional limitation over time. If left untreated, isolated cartilage lesions can lead to progressive chondropenia or global cartilage loss over time. A chondropenia curve is described to help predict the outcome of cartilage injury based on different lesion and patient characteristics. Nutriceuticals and chondroprotective agents are being investigated as tools to slow the development of chondropenia. Several operative techniques have been described for articular cartilage repair or replacement and, more recently, cartilage regeneration. Rehabilitation guidelines are being developed to meet the needs of these new techniques. Next-generation techniques are currently evaluated to optimize articular cartilage repair biology and to provide a repair cartilage tissue that can withstand the high mechanical loads experienced by the athlete with consistent long-term durability.

Chondrogenic differentiation of human subchondral progenitor cells is impaired by rheumatoid arthritis synovial fluid

In microfracture, subchondral progenitors enter the cartilage defect and form cartilage repair tissue. We hypothesize that synovial fluid (SF) from rheumatoid arthritis (RA) donors affects chondrogenesis of human subchondral progenitors stimulated with transforming growth factor-beta3 (TGFB3), whereas SF from normal and osteoarthritis (OA) donors do not. Human progenitors from subchondral cortico-spongious bone (pool of n = 4) were cultured in micromasses under serum-free conditions and were stimulated with 10 ng/mL TGFB3 and with 5% SF from normal, OA, and RA donors (pool of n = 7, each). Histological staining of proteoglycan and immunostaining of type II collagen showed that progenitors stimulated with SF from RA donors show significantly reduced cartilage matrix formation compared to progenitors treated with TGFB3 or with SF from normal and OA donors (n = 3, each). Gene expression analysis of typical chondrocyte marker genes and genes encoding matrix modifying enzymes showed that SF from OA and RA donors influence the onset of TGFB3-mediated chondrogenesis (pool of 20 micromasses), but had no effect on the gene expression profile after prolonged culture in micromasses. These results suggest that SF from RA patients may impair the chondrogenic development of mesenchymal progenitors in microfracture, whereas osteoarthritic SF may has no negative effect on the cartilage matrix formation.

Advances in Tissue Engineering Techniques for Articular Cartilage Repair

The limited repair potential of human articular cartilage contributes to development of debilitating osteoarthritis and remains a great clinical challenge. This has led to evolution of cartilage treatment strategies from palliative to either reconstructive or reparative methods in an attempt to delay or "bridge the gap" to joint replacement. Further development of tissue engineering-based cartilage repair methods have been pursued to provide a more functional biological tissue. Currently, tissue engineering of articular cartilage has three cornerstones; a cell population capable of proliferation and differentiation into mature chondrocytes, a scaffold that can host these cells, provide a suitable environment for cellular functioning and serve as a sustained-release delivery vehicle of chondrogenic growth factors and thirdly, signaling molecules and growth factors that stimulate the cellular response and the production of a hyaline extracellular matrix (ECM). The aim of this review is to summarize advances in each of these three fields of tissue engineering with specific relevance to surgical techniques and technical notes.

Debridement of cartilage lesions before autologous chondrocyte implantation by open or transarthroscopic techniques

We compared the quality of debridement of chondral lesions performed by four arthroscopic (SH, shaver; CU, curette; SHCU, shaver and curette; BP, bipolar electrodes) and one open technique (OPEN, scalpel and curette) which are used prior to autologous chondrocyte implantation (ACI). The ex vivo simulation of all five techniques was carried out on six juvenile equine stifle joints. The OPEN, SH and SHCU techniques were tested on knees harvested from six adult human cadavers.

The most vertical walls with the least adjacent damage to cartilage were obtained with the OPEN technique. The CU and SHCU methods gave inferior, but still acceptable results whereas the SH technique alone resulted in a crater-like defect and the BP method undermined the cartilage wall. The subchondral bone was severely violated in all the equine samples which might have been peculiar to this model. The predominant depth of the debridement in the adult human samples was at the level of the calcified cartilage. Some minor penetrations of the subchondral end-plate were induced regardless of the instrumentation used.

Our study suggests that not all routine arthroscopic instruments are suitable for the preparation of a defect for ACI. We have shown that the preferred debridement technique is either open or arthroscopically-assisted manual curettage. The use of juvenile equine stifles was not appropriate for the study of the cartilage-subchondral bone interface.

Cell-Laden and Cell-Free Matrix-Induced Chondrogenesis versus Microfracture for the Treatment of Articular Cartilage Defects: A Histological and Biomechanical Study in Sheep

OBJECTIVE

The aim of this study was to evaluate the regenerative potential of cell-laden and cell-free collagen matrices in comparison to microfracture treatment applied to full-thickness chondral defects in an ovine model.

METHODS

Animals (n = 30) were randomized into 5 treatment groups, and 7-mm full-cartilage-thickness defects were set at the trochlea and medial condyle of both knee joints and treated as follows: 2 scaffolds in comparison (collagen I/III, Chondro-Gide(®); collagen II, Chondrocell(®)) for covering microfractured defects (autologous matrix-induced chondrogenesis), both scaffolds colonized in vitro with autologous chondrocytes (matrix-associated chondrocyte transplantation), or scaffold-free microfracture technique. One year after surgery, cartilage lesions were biomechanically (indentation test), histologically (O'Driscoll score), and immunohistochemically (collagen type I and II staining) evaluated.

RESULTS

All treatment groups of the animal model induced more repair tissue and showed better histological scores and biomechanical properties compared to controls. The average thickness of the repair tissue was significantly greater when a scaffold was used, especially the collagen I/III membrane. However, none of the index procedures surpassed the others from a biomechanical point of view or based on the histological scoring. Collagen type II expression was better in condylar defects compared to the trochlea, especially in those treated with collagen I/III membranes.

CONCLUSION

Covering of defects with suitable matrices promotes repair tissue formation and is suggested to be a promising treatment option for cartilage defects. However, it failed to improve the biomechanical and histological properties of regenerated articular cartilage compared to microfracture alone in an ovine model under the given circumstances.

Nondestructive assessment of sGAG content and distribution in normal and degraded rat articular cartilage via EPIC-microCT

OBJECTIVE

The objective of this study was to evaluate the feasibility of quantifying the Equilibrium Partitioning of an Ionic Contrast agent via Microcomputed Tomography (EPIC-microCT) to nondestructively assess sulfated glycosaminoglycan (sGAG) content and distribution in rat articular cartilage ex vivo, and in doing so to establish a paradigm for extension of this technique to other small animal models.

DESIGN

After determination of an appropriate incubation time for the anionic contrast agent, EPIC-microCT was used to examine age-related differences in cartilage sGAG content between 4-, 8-, and 16-week old (n=5 each) male Wistar rats and to evaluate sGAG depletion in the right femora of each age group after 60 min of digestion with chondroitinase ABC. The EPIC-microCT measurements were validated by histological safranin-O staining, and reproducibility was evaluated by triplicate scans of six femora.

RESULTS

Cartilage attenuation gradually increased with cumulative digestion time and reached a plateau at approximately 60 min with a 16.0% temporal increase (P<0.01). Average femoral articular cartilage attenuation increased by 14.2% from 4- to 8-weeks of age (P<0.01) and further increased by 2.5% from 8 to 16 weeks (P<0.05). After 60 min of digestion, femoral articular cartilage attenuations increased by 15-17% in each age group (P<0.01). Correspondingly, sGAG optical density decreased with age and digestion, and showed a linear correlation (r=-0.88, slope=-1.26, P<0.01, n=30) with EPIC-microCT cartilage attenuation. High reproducibility was indicated by a low coefficient of variation (1.5%) in cartilage attenuation.

CONCLUSIONS

EPIC-microCT imaging provides high spatial resolution and sensitivity to assess sGAG content and three-dimensional distribution in rat femoral articular cartilage.

Validation of the Knee Injury and Osteoarthritis Outcome Score (KOOS) for the treatment of focal cartilage lesions

OBJECTIVE

To validate the Knee Injury and Osteoarthritis Outcome Score (KOOS) for the treatment of focal cartilage lesions.

METHODS

A total of 40 patients (mean age 35+/-12 years), treated for a focal cartilage lesion in the knee were included in this study. Test-retest data were collected with an intermediate period of 2 days. Patients were asked to complete the Dutch KOOS and complementary questionnaires [short form-36 (SF-36), Lysholm, EuroQol-5D (EQ-5D)] to evaluate the clinimetric properties of the KOOS in terms of internal consistency (Cronbach's alpha), reliability [intra-class-correlation (ICC) and Bland and Altman plots], construct validity (Spearman's rank correlation), floor and ceiling effects and responsiveness.

RESULTS

The Cronbach's alpha of the KOOS subdomains and total score ranged from 0.74 to 0.96. The overall ICC of the KOOS was 0.97 while the subscales ranged from 0.87 to 0.95. The Bland and Altman plots showed a small individual variance between the two assessments in time. Spearman's rank correlations between the subscales of the KOOS and representative subscales of the SF-36, Lysholm and EQ-5D were high to moderate ranging from 0.43 to 0.70. We observed no floor effect while the largest observed ceiling effect was 10.3%. The responsiveness was moderate to large with the effect size ranging from 0.70 to 1.32 and the standardized response mean 0.61 to 0.87.

CONCLUSION

This study illustrates the validity and reliability of the KOOS in measuring the clinical condition of patients after treatment of focal cartilage lesions. This study provides a basis for the use of the KOOS for future clinical research in cartilage repair.

Cell quality affects clinical outcome after MACI procedure for cartilage injury of the knee

The aim of our study was to test the hypothesis that in early follow up after matrix guided autologous chondrocyte implantation (MACI), clinical results do not correlate with radiological and histological results, and that MACI as first line procedure and treatment of traumatic cartilage defects leads to better results compared to second line treatment and treatment of degenerative defects. Six and twelve months after MACI, patients IKDC-score was analysed, as well as the results of MRI-examinations. Specimens of the scaffold were histologically assessed at the time of implantation. The IKDC-score as well as the MRI-score improved significantly during follow up. The number of morphological abnormal cells was correlated with a poor clinical outcome. Defect aetiology proved to be a decisive factor for good clinical outcome. Patients with a short history of trauma (<1 year) and an osteochondritis dissecans were found to have better scores 1 year after MACI than patients with a trauma more than 1 year ago. Defect-size, patients age and -gender did not significantly influence the clinical outcome. No differences were seen when MACI was used as first- or second-line procedure. Defect aetiology and quality of the cells are decisive for the clinical outcome. MACI can produce good and very good clinical results even when used as second-line procedure.

Matrix-assisted autologous chondrocyte transplantation for the repair of cartilage defects of the knee: systematic clinical data review and study quality analysis

BACKGROUND

The clinical application of the second-generation tissue-engineering approach for the treatment of cartilage lesions has been documented for different types of scaffolds, but systematic information on clinical efficacy and long-term results is not available.

PURPOSE

To analyze and assess the quality of clinical studies on different products in the emerging field of matrix-assisted autologous chondrocyte transplantation. The secondary purpose of this review was to improve the quality assessment of studies by modifying the Coleman methodology score (CMS).

STUDY DESIGN

Systematic review.

METHODS

For this review, a literature search was performed to identify all published and unpublished clinical studies of matrix-assisted (second-generation) autologous chondrocyte transplantation using the following medical electronic databases: MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, and British National Library of Health, including the Cochrane Central Register of Controlled Trials (CENTRAL). The search period was January 1, 1995, to July 1, 2008. To better assess cartilage-related studies, a modification of the CMS was proposed.

RESULTS

Eighteen studies were included in the analysis, reporting on 731 patients with an average follow-up of 27.3 months (6.5-60.0 months). Of the 18 studies, 2 were randomized controlled studies, 3 were prospective comparative studies, 11 were prospective cohort studies or prospective case series, and 2 were retrospective case series. Original CMSs for these studies (55.1 +/- 1.6) were significantly higher than those of cartilage repair studies in general (43.5 +/- 1.6, P < .0001) reported in 2005. The statistical analysis indicated that the modified CMS showed higher correlations and lower variability of correlations among 3 reviewers.

CONCLUSION

The quality of the currently available data on second-generation autologous chondrocyte transplantation is still limited by study designs. The modified CMS has demonstrated better sensitivity and reproducibility with respect to the original score, so it can be recommended for cartilage clinical studies evaluation.