Publications (34)88.67 Total impact
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Article: Is gender influencing the biomechanical results after autologous chondrocyte implantation?
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ABSTRACT: PURPOSE: The influence of gender on the biomechanical outcome after autologous chondrocyte implantation (ACI) including isokinetic muscle strength measurements has not been investigated. The present prospective study was performed to evaluate gender-specific differences in the biomechanical function 48 months after ACI. METHODS: Fifty-two patients (mean age 35.6 ± 8.5 years) that met our inclusion criteria, underwent ACI with Bioseed C(®) and were evaluated with the KOOS score preoperatively, 6, 12 and 48 months after surgery. At final follow-up, 44 out of the 52 patients underwent biomechanical evaluation with isokinetic strength measurements of both knees. All data were evaluated separately for men and women and compared for each time interval using the Mann-Whitney U test. RESULTS: Clinical scores improved significantly over the whole study period (p < 0.05). Male patients demonstrated significantly better scores during the follow-up in the KOOS score (p < 0.05). Isokinetic strength measurements after 48 months revealed a significant strength deficit of the treated knee in all test modes compared to the healthy extremity (p < 0.05). Furthermore, male patients achieved significantly higher strength values compared to female patients (p < 0.05). CONCLUSIONS: ACI is a viable treatment option for full-thickness chondral defects in the knee of both genders. Isokinetic muscle strength measures are significantly worse in women (p < 0.05), but physiological and may play a role for the explanation of gender-specific results after ACI. LEVEL OF EVIDENCE: II.Knee Surgery Sports Traumatology Arthroscopy 11/2012; · 2.21 Impact Factor -
Article: Repair of focal cartilage defects with scaffold-assisted autologous chondrocyte grafts: clinical and biomechanical results 48 months after transplantation.
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ABSTRACT: Scaffold-assisted autologous chondrocyte implantation is a clinically effective procedure for cartilage repair, but biomechanical evaluations are still missing. 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. Case series; Level of evidence, 4. 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. 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). 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.The American journal of sports medicine 05/2011; 39(8):1697-705. · 3.61 Impact Factor -
Article: Autologous chondrocyte implantation (ACI) for the treatment of large and complex cartilage lesions of the knee.
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ABSTRACT: 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. 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. 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. 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.Sports Medicine Arthroscopy Rehabilitation Therapy & Technology 01/2011; 3:11. -
Article: Comparison of arthroscopic and open assessment of size and grade of cartilage defects of the knee.
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ABSTRACT: The purpose of our study was to compare arthroscopic versus open measurement of cartilage defects and determination of defect grade according to the International Cartilage Repair Society (ICRS) classification. Arthroscopic determination of defect size and grade according to the ICRS classification of 450 focal cartilage defects in 407 patients who underwent autologous chondrocyte implantation was compared with definite findings at the time of open knee surgery. Results were analyzed based on defect location, defect size, and experience of the treating surgeon. Open evaluation of all cartilage defects showed a mean size of 4.54 ± 2.11 cm², whereas arthroscopic determination resulted in a significantly larger mean defect size of 5.69 ± 1.81 cm² (P < .001, r = 0.757). This observation was found in all subgroups concerning defect location and experience of the treating surgeon (P < .001). Overestimation was pronounced among inexperienced surgeons (all P < .01) and in smaller defects (P < .01). Concerning grading of the defect according to the ICRS classification, there was a consensus in 80.9% of the cases when arthroscopic grading was compared with open grading. No differences were found based on defect location or experience of the treating surgeon (P > .05). Although a high correlation was found between arthroscopic and open evaluation of the cartilage defect size, there is a significant overestimation of the cartilage defect size during arthroscopy. This observation is independent of defect location. Smaller defects and inexperienced surgeons are factors that make an overestimation of defect size more likely. Arthroscopic detection and estimation of the full-thickness cartilage defects according to the ICRS classification seem reliable. Level IV, therapeutic case series.Arthroscopy The Journal of Arthroscopic and Related Surgery 10/2010; 27(1):46-51. · 3.02 Impact Factor -
Article: Chondrogenic differentiation of human subchondral progenitor cells is impaired by rheumatoid arthritis synovial fluid.
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ABSTRACT: 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.Journal of Orthopaedic Research 06/2010; 28(6):819-27. · 2.81 Impact Factor -
Article: Long-term durability of autologous chondrocyte implantation: a multicenter, observational study in US patients.
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ABSTRACT: Autologous chondrocyte implantation for full-thickness lesions of the distal femur has demonstrated good short- to midterm clinical improvement. However, long-term durability (>5 years) of autologous chondrocyte implantation has not been evaluated in US patients to date. Patients who improve from baseline to early follow-up will sustain improvement at later follow-up. Case series, Level of evidence, 4. Cartilage Repair Registry patients with full-thickness distal femur lesions who were treated with autologous chondrocyte implantation before December 31, 1996 and had modified overall Cincinnati scores at baseline and 1- to 5-year follow-up scores were re-evaluated at 6- to 10-year follow-up. Autologous chondrocyte implantation durability was determined by comparing early (1-5 years) to long-term (6-10 years) outcomes. Adverse events and treatment failures were recorded. Results Seventy-two patients met eligibility criteria (at baseline: mean age, 37 years; mean lesion size, 5.2 cm(2); and overall condition score, 3.4 points [poor]). Eighty-seven percent of patients (47 of 54) who improved at the earlier follow-up period sustained a mean improvement in overall condition score of 3.8 points from baseline to the later follow-up period (P < .001). From baseline to 10-year follow-up (mean follow-up, 9.2 years), 69% improved, 17% failed, and 12.5% reported no change from baseline. Most failures (75% [9 of 12]) occurred at a mean follow-up of 2.5 years. Thirty patients (42%) had 42 operations after autologous chondrocyte implantation; 24 operations (57%) occurred in patients who met the study definition of failure. Treatment with autologous chondrocyte implantation for large, symptomatic, full-thickness lesions of the distal femur can result in early improvement that is sustained at longer follow-up (up to 10 years) in the majority of patients.The American journal of sports medicine 02/2010; 38(2):238-46. · 3.61 Impact Factor -
Article: Changes in content and synthesis of collagen types and proteoglycans in osteoarthritis of the knee joint and comparison of quantitative analysis with Photoshop-based image analysis.
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ABSTRACT: The different cartilage layers vary in synthesis of proteoglycan and of the distinct types of collagen with the predominant collagen Type II with its associated collagens, e.g. types IX and XI, produced by normal chondrocytes. It was demonstrated that proteoglycan decreases in degenerative tissue and a switch from collagen type II to type I occurs. The aim of this study was to evaluate the correlation of real-time (RT)-PCR and Photoshop-based image analysis in detecting such lesions and find new aspects about their distribution. We performed immunohistochemistry and histology with cartilage tissue samples from 20 patients suffering from osteoarthritis compared with 20 healthy biopsies. Furthermore, we quantified our results on the gene expression of collagen type I and II and aggrecan with the help of real-time (RT)-PCR. Proteoglycan content was measured colorimetrically. Using Adobe Photoshop the digitized images of histology and immunohistochemistry stains of collagen type I and II were stored on an external data storage device. The area occupied by any specific colour range can be specified and compared in a relative manner directly from the histogram using the "magic wand tool" in the select similar menu. In the image grow menu gray levels or luminosity (colour) of all pixels within the selected area, including mean, median and standard deviation, etc. are depicted. Statistical Analysis was performed using the t test. With the help of immunohistochemistry, RT-PCR and quantitative RT- PCR we found that not only collagen type II, but also collagen type I is synthesized by the cells of the diseased cartilage tissue, shown by increasing amounts of collagen type I mRNA especially in the later stages of osteoarthritis. A decrease of collagen type II is visible especially in the upper fibrillated area of the advanced osteoarthritic samples, which leads to an overall decrease. Analysis of proteoglycan showed a loss of the overall content and a quite uniform staining in the different zones compared to the healthy cartilage with a classical zonal formation. Correlation analysis of the proteoglycan Photoshop measurements with the RT-PCR using Spearman correlation analysis revealed strong correlation for Safranin O and collagen type I, medium for collagen type II and glycoprotein but weak correlation between PCR aggrecan results. Photoshop-based image analysis might become a valuable supplement for well known histopathological grading systems of lesioned articular cartilage.Archives of Orthopaedic and Trauma Surgery 10/2009; 130(4):557-64. · 1.37 Impact Factor -
Article: Autologous chondrocyte implantation versus ACI using 3D-bioresorbable graft for the treatment of large full-thickness cartilage lesions of the knee.
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ABSTRACT: In autologous chondrocyte implantation (ACI), the periosteum patch which is sutured over the cartilage defect has been identified as a major source of complications such as periosteal hypertrophy. In the present retrospective study, we compared midterm results of first-generation ACI with a periosteal patch to second generation ACI using a biodegradable collagen fleece (BioSeed-C) in 82 patients suffering from chronic posttraumatic and degenerative cartilage lesions of the knee. Clinical outcome was assessed in 42 patients of group 1 and in 40 patients of group 2 before implantation of the autologous chondrocytes and at a minimum follow-up of 2 years using the ICRS score, the modified Cincinnati score and the Lysholm score. Although patients treated with BioSeed-C had more previous surgical procedures on their respective knees, highly significant improvements (P < 0.001) were assessed in both groups at comparable outcome levels: the ICRS score improved from grade D (poor) preoperatively to grade C (fair); the modified Cincinnati knee score from 3.26 to 6.4 (group 1) and 3.3 and 6.88 (group 2). Lysholm score improved from 33 to 70 points (group 1) and from 47 to 78 points (group 2), respectively. Revision surgery was due to symptomatic periosteal hypertrophy (n = 4), graft failure (n = 3), plica syndrome (n = 2) synovectomy (n = 1) (group 1); and graft failure (n = 2), debridement (n = 1), synovectomy (n = 2) (group 2). These results suggest that BioSeed-C is an equally effective treatment option for focal degenerative chondral lesions of the knee in this challenging and complex patient profile.Archives of Orthopaedic and Trauma Surgery 09/2009; 130(8):957-64. · 1.37 Impact Factor -
Article: Formation of cartilage repair tissue in articular cartilage defects pretreated with microfracture and covered with cell-free polymer-based implants.
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ABSTRACT: The aim of our study was to evaluate the mid-term outcome of a cell-free polymer-based cartilage repair approach in a sheep cartilage defect model in comparison to microfracture treatment. Cell-free, freeze-dried implants (chondrotissue) made of a poly-glycolic acid (PGA) scaffold and hyaluronan were immersed in autologous serum and used for covering microfractured full-thickness articular cartilage defects of the sheep (n = 4). Defects treated with microfracture only served as controls (n = 4). Six months after implantation, cartilage implants and controls were analyzed by immunohistochemical staining of type II collagen, histological staining of proteoglycans, and histological scoring. Histological analysis showed the formation of a cartilaginous repair tissue rich in proteoglycans. Histological scoring documented significant improvement of repair tissue formation when the defects were covered with the cell-free implant, compared to controls treated with microfracture. Immunohistochemistry showed that the cell-free implant induced cartilaginous repair tissue and type II collagen. Controls treated with microfracture showed marginal formation of a mixed-type repair tissue consisting of cartilaginous tissue and fibro-cartilage. Covering of microfractured defects with the cell-free polymer-based cartilage implant is suggested to be a promising treatment option for cartilage defects and improves the regeneration of articular cartilage.Journal of Orthopaedic Research 05/2009; 27(10):1353-60. · 2.81 Impact Factor -
Article: Treatment of focal degenerative cartilage defects with polymer-based autologous chondrocyte grafts: four-year clinical results.
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ABSTRACT: Second-generation autologous chondrocyte implantation with scaffolds stabilizing the grafts is a clinically effective procedure for cartilage repair. In this ongoing prospective observational case report study, we evaluated the effectiveness of BioSeed-C, a cell-based cartilage graft based on autologous chondrocytes embedded in fibrin and a stable resorbable polymer scaffold, for the treatment of clinical symptomatic focal degenerative defects of the knee. Clinical outcome after 4-year clinical follow-up was assessed in 19 patients with preoperatively radiologically confirmed osteoarthritis and a Kellgren-Lawrence score of 2 or more. Clinical scoring was performed before implantation of the graft and 6, 12, and 48 months after implantation using the Lysholm score, the Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee (IKDC) score, and the International Cartilage Repair Society (ICRS) score. Cartilage regeneration and articular resurfacing were assessed by magnetic resonance imaging (MRI) 4 years after implantation of the autologous cartilage graft. Significant improvement (P < 0.05) of the Lysholm and ICRS scores was observed as early as 6 months after implantation of BioSeed-C and remained stable during follow-up. The IKDC score showed significant improvement compared with the preoperative situation at 12 and 48 months (P < 0.05). The KOOS showed significant improvement in the subclasses pain, activities of daily living, and knee-related quality of life 6 months as well as 1 and 4 years after implantation of BioSeed-C in osteoarthritic defects (P < 0.05). MRI analysis showed moderate to complete defect filling with a normal to incidentally hyperintense signal in 16 out of 19 patients treated with BioSeed-C. Two patients without improvement in the clinical and MRI scores received a total knee endoprosthesis after 4 years. The results show that the good clinical outcome achieved 1 year after implantation of BioSeed-C remains stable over the course of a period of 4 years and suggest that implanting BioSeed-C is a promising treatment option for the repair of focal degenerative defects of the knee.Arthritis research & therapy 03/2009; 11(2):R33. · 4.27 Impact Factor -
Article: Chondrogenic differentiation capacity of human mesenchymal progenitor cells derived from subchondral cortico-spongious bone.
Journal of Orthopaedic Research 11/2008; 26(11):1547. · 2.81 Impact Factor -
Article: Cell-laden and cell-free biopolymer hydrogel for the treatment of osteochondral defects in a sheep model.
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ABSTRACT: The objective of the current study was to determine the suitability of cell-laden and cell-free alginate-gelatin biopolymer hydrogel for osteochondral restoration in a sheep model (n = 12). Four femoral defects per animal were filled with hydrogel (cHG) plus autologous chondrocytes (cHG + C) or periosteal cells (cHG + P) or gel only (cHG) or were left untreated (E). In situ solidification enabled instantaneous implant fixation. Sixteen weeks postoperatively, defect sites were processed for light microscopy and immunofluorescence. A modified Mankin and a semi-quantitative immunoreactivity score were used to evaluate histology and immunofluorescence, respectively. Defects after cHG + C were restored with smooth, hyaline-like neo-cartilage and trabecular subchondral bone. cHG + P and cHG treatments revealed slightly inferior regenerate morphology. Undifferentiated tissue was found in E. The histological score showed significant (p < 0.05) differences between all treatment groups. In conclusion, cHG induces satisfactory defect regeneration. Complete filling of the cavity in one step and subsequent rapid in situ solidification was feasible and facilitated graft fixation. Cell implantation might be beneficial, because cells seem to play a key role in histological outcome. Still, their contribution to the repair process remains unresolved because host cell influx takes place. The combination of alginate and gelatin, however, creates an environment capable of serving implanted and host cells for osteo-chondrogenic tissue regeneration.Tissue Engineering Part A 10/2008; 15(1):75-82. · 4.64 Impact Factor -
Article: [Matrix-augmented autologous chondrocyte implantation in the knee--arthroscopic technique].
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ABSTRACT: Arthroscopic implantation of resorbable, three-dimensional scaffolds for the treatment of full-thickness cartilage defects. Full-thickness cartilage defect mainly in the knee joint. Advanced osteoarthritis, rheumatoid arthritis, avascular osteonecrosis. Debridement of the defect, assessment of the defect size, sizing of the implant, implantation into the joint, and fixation. Continuous active and passive motion, pain-adapted weight bearing with crutches, possibly toe-touch loading depending on size and localization of the defect. After 2 years, good and excellent results in 80% of the cases with femoral cartilage defects on the modified Cincinnati Knee Rating Scale. Inferior results for defects of the patella and tibia.Operative Orthopädie und Traumatologie 10/2008; 20(3):199-207. · 0.46 Impact Factor -
Article: Characteristic complications after autologous chondrocyte implantation for cartilage defects of the knee joint.
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ABSTRACT: Although autologous chondrocyte implantation (ACI) is a well-established therapy for the treatment of isolated cartilage defects of the knee joint, little is known about typical complications and their treatment after ACI. Unsatisfactory outcome after ACI is associated with technique-related typical complications. Case series; Level of evidence, 4. A total of 309 consecutive patients with 349 ACI procedures of the knee joint were analyzed. Three different ACI techniques were used: periosteum-covered ACI in 52 cases (14.9%), Chondrogide (Geistlich Biomaterials, Wolhusen, Switzerland) membrane-covered ACI in 215 cases (61.6%), and a 3-dimensional matrix-associated ACI (BioSeed-C, Biotissue Technologies, Freiburg, Germany) in 82 cases (23.5%). In 52 patients, revision surgery was performed for persistent clinical problems. These patients were analyzed for defect size and location, technique of ACI, and intraoperative findings during revision surgery. The mean time of follow-up for patients after ACI was 4.5 years (standard deviation, +/- 1.5). Four typical major complications were identified: hypertrophy of the transplant, disturbed fusion of the regenerative cartilage and the healthy surrounding cartilage, insufficient regenerative cartilage, and delamination. These diagnoses covered a total of 88.5% of the patients who underwent revision surgery. The overall complication rate was highest in the group of patients treated with periosteum-covered ACI (P = .008). The incidence of symptomatic hypertrophy was 5.2% for all techniques and defect locations; the highest incidence was in patients treated with periosteum-covered ACI (15.4%) (P = .001). The incidence of disturbed fusion was highest in the Chondrogide-covered ACI (3.7%) and the matrix-associated ACI group (4.8%). Concerning the incidence of complications by defect location, there was a tendency for increased complications in patellar defects (P = .095). Within the patellar defects group, no correlation was found for the occurrence of delamination, insufficient regeneration, and disturbed fusion. As a statistical trend, an increased rate of hypertrophy was found for patellar defects (P = .091). A major proportion of complications after ACI can be summarized by 4 major diagnoses (symptomatic hypertrophy, disturbed fusion, delamination, and graft failure). Among those, the overall complication rate and incidence of hypertrophy of the transplant were higher for periosteum-covered ACI. Furthermore, an increased rate of symptomatic hypertrophy was found for patellar defects. Therapeutic concepts need to be developed to treat these typical complications of ACI.The American journal of sports medicine 10/2008; 36(11):2091-9. · 3.61 Impact Factor -
Article: Arthroskopische Technik der matrixassoziierten autologen Knorpelzelltransplantation am Kniegelenk
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ABSTRACT: Operationsziel Arthroskopische Rekonstruktion der Gelenkfläche mit resorbierbaren Zellträgern zur Behandlung vollschichtiger Knorpeldefekte und damit zur langfristigen Vermeidung einer Progression der Arthrose. Indikationen Vollschichtige, bis auf den Knochen reichende Knorpeldefekte im Kniegelenk. Kontraindikationen Fortgeschrittene Arthrose, Arthritis, Knochennekrosen. Operationstechnik Arthroskopisches Débridement des Knorpeldefekts, Ausmessen der Defektgröße, Anpassen des Implantats, Einführen in das Gelenk und Fixation. Weiterbehandlung Aktive und passive Gelenkmobilisation, schmerzadaptierter Belastungsaufbau, ggf. initiale Entlastung in Abhängigkeit von Lokalisation und Größe des Defekts. Ergebnisse 45 Patienten mit einem Durchschnittsalter von 39 Jahren wurden in der beschriebenen Technik behandelt. Im Mittel waren 3,3 Knorpeloperationen vorausgegangen. Die ersten 20 Patienten mit einem Nachuntersuchungszeitraum von 2 Jahren und einer mittleren Defektgröße von 4,52 cm2verbesserten sich in ihren klinischen Zustand nach dem modifizierten Cincinnati-Score von 3,5 auf 6,2 Punkte (Maximum 10 Punkte). 17 Patienten wurden arthroskopisch transplantiert. Schlechtere Ergebnisse wurden bei Defekten der Patella oder der Tibia erreicht. Es traten keine spezifischen Komplikationen auf. Objective Arthroscopic implantation of resorbable, three-dimensional scaffolds for the treatment of full-thickness cartilage defects. Indications Full-thickness cartilage defect mainly in the knee joint. Contraindications Advanced osteoarthritis, rheumatoid arthritis, avascular osteonecrosis. Surgical Technique Debridement of the defect, assessment of the defect size, sizing of the implant, implantation into the joint, and fixation. Postoperative Management Continuous active and passive motion, pain-adapted weight bearing with crutches, possibly toe-touch loading depending on size and localization of the defect. Results After 2 years, good and excellent results in 80% of the cases with femoral cartilage defects on the modified Cincinnati Knee Rating Scale. Inferior results for defects of the patella and tibia.Operative Orthopädie und Traumatologie 01/2008; 20(3):199-207. · 0.46 Impact Factor -
Article: Regeneration of ovine articular cartilage defects by cell-free polymer-based implants.
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ABSTRACT: The aim of our study was the evaluation of a cell-free cartilage implant that allows the recruitment of mesenchymal stem and progenitor cells by chemo-attractants and subsequent guidance of the progenitors to form cartilage repair tissue after microfracture. Chemotactic activity of human serum on human mesenchymal progenitors was tested in 96-well chemotaxis assays and chondrogenic differentiation was assessed by gene expression profiling after stimulating progenitors with hyaluronan in high-density cultures. Autologous serum and hyaluronan were combined with polyglycolic acid (PGA) scaffolds and were implanted into full-thickness articular cartilage defects of the sheep pre-treated with microfracture. Defects treated with microfracture served as controls. Human serum was a potent chemo-attractant and efficiently recruited mesenchymal progenitors. Chondrogenic differentiation of progenitors upon stimulation with hyaluronan was shown by the induction of typical chondrogenic marker genes like type II collagen and aggrecan. Three months after implantation of the cell-free implant, histological analysis documented the formation of a cartilaginous repair tissue. Controls treated with microfracture showed no formation of repair tissue. The cell-free cartilage implant consisting of autologous serum, hyaluronan and PGA utilizes the migration and differentiation potential of mesenchymal progenitors for cartilage regeneration and is well suited for the treatment of cartilage defects after microfracture.Biomaterials 01/2008; 28(36):5570-80. · 7.40 Impact Factor -
Chapter: Additional Reading
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ABSTRACT: Principles of Cartilage Repair 10.1007/978-3-7985-1593-2_6 ChristophErggelet, BertR.Mandelbaum, EikeH.Mrosek and JasonM.Scopp Additional Reading12/2007: pages 73-75; -
Article: Mechanical testing of fixation techniques for scaffold-based tissue-engineered grafts.
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ABSTRACT: Full-thickness defects in articular cartilage can be functionally restored by autologous chondrocyte implantation (ACI). In past years, numerous types of scaffolds for tissue-engineered cartilage implants have been developed and thoroughly characterized. However, the fixation stability of the implants has been rarely investigated despite its well-known importance for successful therapy. In this study, we have mechanically tested the fixation stability of four commonly used biomaterials for ACI attached by four different fixation techniques (unfixed, fibrin glue, chondral suture, and transosseous suture) in situ. Scaffolds based on polyglycolic acid (PGA) and polyglycolic acid and poly-L-lactic acid (PGLA), collagen membranes, and a gel-like matrix material were fixed within rectangular full-thickness cartilage defects of 10 x 15 mm(2) and loaded in tension until failure. Fibrin glue fixation of PGLA-scaffolds withstood a load of 2.18 6 +/- 0.47 N, chondral sutured PGA-scaffolds of 26.29 6 +/- 1.55 N, and transosseous fixed PGA-scaffolds of 38.18 6 +/- 9.53 N. The PGA-scaffold could be loaded highest until failure for all fixation techniques compared to the PGLA-scaffold and collagen membrane. Our findings serve as basis for selecting the most suitable fixation technique for scaffold-based tissue-engineered grafts according to the expected in vivo loads.Journal of Biomedical Materials Research Part B Applied Biomaterials 11/2007; 83(1):50-7. · 2.15 Impact Factor -
Article: Synovial fluid recruits human mesenchymal progenitors from subchondral spongious bone marrow.
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ABSTRACT: Microfracture is a frequently used reparative technique that induces a healing response in articular cartilage defects. Penetration of the subchondral bone leads to blood clot formation, allows multipotent mesenchymal cells to access the defect and, subsequently, leads to cartilaginous repair tissue. The aim of our study was to analyze the chemotactic recruitment of human subchondral spongious bone marrow-derived cells by synovial fluid (SF) from normal donors (ND), patients with osteoarthritis (OA) and rheumatoid arthritis (RA). Subchondral spongious bone marrow-derived mesenchymal progenitors were isolated from bone cylinders after high tibial osteotomy and analyzed for the presence of stem cell-related cell surface antigens by flow cytometry. Recruitment of subchondral progenitors by normal SF and SF from donors with degenerated joint diseases was documented by using a modified Boyden chamber chemotaxis assay. The chemotaxis assay demonstrated that synovial fluid has the potential to recruit mesenchymal progenitors in vitro. SF from normal donors and patients with OA showed no difference in the potential to stimulate cell migration. SF obtained from RA donors showed significantly reduced cell recruitment compared to SF derived from OA patients (p = 0.0054) and normal donors (p < 0.0001). The chemotactic activity of SF obtained from normal donors and from patients with degenerative joint diseases suggests that SF may be actively involved in the migration of progenitors in cartilage defects after microfracture.Journal of Orthopaedic Research 10/2007; 25(10):1299-307. · 2.81 Impact Factor -
Article: Autologous chondrocyte implantation for the treatment of retropatellar cartilage defects: clinical results referred to defect localisation.
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ABSTRACT: Although autologous chondrocyte implantation (ACI) has become well established for the treatment of full-thickness cartilage defects of the knee joint, nevertheless clinical results of retropatellar lesions are still inferior compared to those of defects located on femoral condyles. We report the clinical results obtained in 70 patients treated with ACI for full-thickness defects of the patella, with special reference to defect location and size, age, body mass index and sports activity. At a follow-up of 38.4 months (range 14-64, follow-up rate 83.3%), patients' subjective functional knee scores (IKDC, Lysholm) were analysed, as were the results of objective examination (according to ICRS). Mean patient age at the time of surgery was 34.3 years (+/-10.1). The mean Lysholm score at the time of follow-up was 73.0 (+/-22.4) and the subjective IKDC score was 61.6 (+/-21.5); normal and nearly normal clinical results according to the objective criteria of the International Cartilage Research Society (ICRS) were achieved in 67.1% of the patients, while abnormal results were achieved in 20.0% of the patients and severely abnormal results, in 12.9%. While different surgical techniques did not seem to have any significant influence on the treatment results, both defect size and defect location within the patella were found to be significantly associated with clinical outcome. The corollaries to this are that larger cartilage lesions of the patella are associated with an inferior outcome (p = 0.007) and that cartilage defects located on the lateral patellar facet are correlated with a better clinical outcome than those located on the medial facet or those involving both facets (p = 0.017). This study demonstrates that within a group of patients treated with ACI for retropatellar cartilage lesion there are significant differences in clinical outcome, which are important and should be taken into account of when a decision has to be made on whether or not ACI is indicated.Archives of Orthopaedic and Trauma Surgery 09/2007; 128(11):1223-31. · 1.37 Impact Factor
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2011
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University of Zurich
Zürich, ZH, Switzerland
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2010
-
Alamo Bone & Joint Clinic
San Antonio, TX, USA
-
-
2007–2010
-
TransTissue
Freiberg, Saxony, Germany
-
-
2003–2009
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Universität Freiburg
- Department of Orthopedics and Traumatology
Freiburg, Lower Saxony, Germany
-
-
2003–2008
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Universitätsklinikum Freiburg
Freiburg, Lower Saxony, Germany
-
-
2006
-
Mayo Foundation for Medical Education and Research
- Department of Orthopaedic Surgery
Scottsdale, AZ, USA -
Kantonsspital St. Gallen
Sankt Gallen, SG, Switzerland
-
-
2005
-
University of Missouri - Kansas City
- Department of Orthopaedic Surgery
Kansas City, MO, USA
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