Ralf Mueller-Rath

Assessment of leech therapy for knee osteoarthritis: A randomized study

Background and purposeu2003Symptomatic treatment of osteoarthritis of the knee with leeches is presently undergoing a renaissance. Previous studies have shown methodical weaknesses. In the present study patients were blinded regarding the treatment, and a control group was included to explore possible differences in various subjective clinical scores and intake of pain medication over time between leech therapy and placebo control. Patients and methodsu2003113 patients with advanced osteoarthritis of the knee were included. The patients were randomized to a single treatment group, group I (single leech application, n = 38), a double treatment group, group II (double application, n = 35), and a control group (n = 40). The second treatment in group II took place after an interval of 4 weeks. The treatment in the control group was simulated with the help of an “artificial leech”. Results were documented with the KOOS and WOMAC scores and also a visual analog scale (VAS) for pain. Changes in the use of pain medication were monitored over 26 weeks. Resultsu2003An improvement in KOOS and WOMAC scores, and also in VAS, was found in all 3 groups following treatment. These improvements were statistically significant for treatment groups I and II during the complete follow-up period. The reduction in individual requirements for pain medication was also statistically significant. The greatest improvement was seen in the group treated twice with the leeches, with a long-term reduction of joint stiffness and improved function in the activities of daily living. Interpretationu2003Leech therapy can reduce symptoms caused by osteoarthritis. Repeated use of the leeches appears to improve the long-term results. We have not determined whether the positive outcome of the leech therapy is caused by active substances released during the leeching, the placebo effect, or the high expectations placed on this unusual treatment form.

In vitro comparison of six different matrix systems for the cultivation of human chondrocytes

SummaryIn recent years, a great variety of different matrix systems for the cultivation of chondrocytes have been developed. Although some of these scaffolds show promising experimental results in vitro, the potential clinical value remains unclear. In this comparative study, we propagated human articular chondrocytes precultivated in monolayer culture on six different scaffolds (collagen gels, membranes and sponges) under standardized in vitro conditions. Mechanical properties of the matrix systems were not improved significantly by cultivation of human chondrocytes under the given in vitro conditions. The gel systems (CaReS, Ars Artho, Germany and Atelocollagen, Koken, Japan) showed a homogeneous cell distribution; chondrocytes propagated on Chondro-Gide (Geistlich Biomaterials, Switzerland) and Integra membranes (Integra, USA) were building multilayers. Only few cells penetrated the two Atelocollagen honeycomb sponges (Koken, Japan). During cultivation, chondrocytes propagated on all systems showed a partial morphological redifferentiation, which was best with regard to the gel systems. In general, only small amounts of collagen type-II protein could be detected in the pericellular region and chondrocytes failed to build a territorial matrix. During the first two weeks of cultivation, the two gel systems showed a significantly higher collagen type-II gene expression and a lower collagen type-I gene expression than the other investigated matrix systems. Although collagen gels seem to be superior when dealing with deep cartilage defects, membrane systems might rather be useful in improving conventional autologous chondrocyte transplantation or in combination with gel systems.

A comparative study of 3 different cartilage repair techniques

PurposeThe value of cell-free techniques in the treatment of cartilage defects remains under debate. In this study, cartilage repair of full-thickness chondral defects in the knees of Goettinger minipigs was assessed by treatment with a cell-free collagen type-I gel or a collagen type-I gel seeded with autologous chondrocytes. As a control, abrasion arthroplasty was included.MethodsIn 18 adult Goettinger minipigs, three full-thickness chondral defects were created in one knee of the hind leg. They were either treated with a cell-free collagen gel, a collagen gel seeded with 2xa0×xa0105/ml chondrocytes, or left untreated. All animals were allowed unlimited weight bearing. At 6, 12, and 52xa0weeks, 6 animals were sacrificed. Immediately after recovery, a non-destructive biomechanical testing was performed. The repair tissue quality was evaluated histologically, and the O’Driscoll score was calculated.ResultsAfter 6xa0weeks, a high number of cells migrated into the initially cell-free collagen gel. After 1xa0year, a hyaline-like repair tissue in both groups has been created. As assessed by O’Driscoll scoring and col-II staining, repair tissue quality of the initially cell-free gel was equal to defects treated by cell-seeded collagen gel implantation after 1xa0year. All untreated control defects displayed a fibrous repair tissue. The mechanical properties represented by the e-modulus were inconsistent in the course of the study. Conclusions The implantation of a cell-free collagen type-I gel can lead to a high-quality repair tissue in the Goettinger minipig that equals a cell-based procedure after 1xa0year postoperatively. This study demonstrates the high chondrogenic potential of the applied collagen gel, which might help to overcome the disadvantages inherent in conventional cartilage tissue engineering methods.

Simultaneous anabolic and catabolic responses of human chondrocytes seeded in collagen hydrogels to long-term continuous dynamic compression.

Cartilage repair strategies increasingly focus on the in vitro development of cartilaginous tissues that mimic the biological and mechanical properties of native articular cartilage. However, current approaches still face problems in the reproducible and standardized generation of cartilaginous tissues that are both biomechanically adequate for joint integration and biochemically rich in extracellular matrix constituents. In this regard, the present study investigated whether long-term continuous compressive loading would enhance the mechanical and biological properties of such tissues. Human chondrocytes were harvested from 8 knee joints (n=8) of patients having undergone total knee replacement and seeded into a collagen type I hydrogel at low density of 2×10(5)cells/ml gel. Cell-seeded hydrogels were cut to disks and subjected to mechanical stimulation for 28 days with 10% continuous cyclic compressive loading at a frequency of 0.3 Hz. Histological and histomorphometric evaluation revealed long-term mechanical stimulation to significantly increase collagen type II and proteoglycan staining homogenously throughout the samples as compared to unstimulated controls. Gene expression analyses revealed a significant increase in collagen type II, collagen type I and MMP-13 gene expression under stimulation conditions, while aggrecan gene expression was decreased and no significant changes were observed in the collagen type II/collagen type I mRNA ratio. Mechanical propertywise, the average value of elastic stiffness increased in the stimulated samples. In conclusion, long-term mechanical preconditioning of human chondrocytes seeded in collagen type I hydrogels considerably improves biological and biomechanical properties of the constructs, corroborating the clinical potential of mechanical stimulation in matrix-associated autologous chondrocyte transplantation (MACT) procedures.

Condensed cellular seeded collagen gel as an improved biomaterial for tissue engineering of articular cartilage.

Three-dimensional autologous chondrocyte implantation based on collagen gel as matrix scaffold has become a clinically applied treatment for focal defects of articular cartilage. However, the low biomechanical properties of collagen gel makes intraoperative handling difficult and creates the risk of early damages to the vulnerable implant. The aim of the study was to create a stabilized form of collagen gel and to evaluate its biomechanical and biochemical properties.Collagen type-I gel was seeded with human articular chondrocytes. 20 samples were subject to condensation which was achieved mechanically by compression and filtration. Control samples were left uncondensed. From both types of gels 10 samples were used for initial biomechanical evaluation by means of unconfined compression and 10 samples were cultivated under standard conditions in vitro. Following cultivation the samples were evaluated by conventional histology and immunohistochemistry. The proliferation rate was calculated and matrix gene expression was quantified by real-time PCR.The biomechanical tests revealed a higher force carrying capacity of the condensed specimens. Strain rate dependency and relaxation was seen in both types of collagen gel representing viscoelastic material properties. Cells embedded within the condensed collagen gel were able to produce extracellular matrix proteins and showed proliferation.Condensed collagen gel represents a mechanically improved type of biomaterial which is suitable for three-dimensional autologous chondrocyte implantation.

Continuous cyclic compressive loading modulates biological and mechanical properties of collagen hydrogels seeded with human chondrocytes.

PURPOSEnThis study investigated the potential of cyclic compressive loading in the generation of in vitro engineered cartilaginous tissue with the aim of contributing to a better understanding of mechanical preconditioning and its possible role in further optimizing existing matrix-associated cartilage replacement procedures.nnnMETHODSnHuman chondrocytes were harvested from 12 osteoarthritic knee joints and seeded into a type I collagen (col-I) hydrogel at low density (2 × 10(5) cells/ml gel). The cell-seeded hydrogel was condensed and cultivated under continuous cyclic compressive loading (frequency: 0.3 Hz; strain: 10%) for 14 days under standardized conditions. After retrieval, specimens were subject to staining, histomorphometric evaluation, gene expression analysis and biomechanical testing.nnnRESULTSnCellular morphology was altered by both stimulation and control conditions as was staining for collagen II (col-II). Gene expression measurements revealed a significant increase for col-II under either cultivation condition. No significant differences in col-I, aggrecan and MMP-13 gene expression profiles were found. The col-II/col-I mRNA ratio significantly increased under stimulation, whereas the biomechanical properties deteriorated under either cultivation method.nnnCONCLUSIONSnAlthough the effects observed are small, mechanical preconditioning has demonstrated its potential to modulate biological properties of collagen hydrogels seeded with human chondrocytes.

Measures for reducing ultra-high-molecular-weight polyethylene wear in total knee replacement: a simulator study.

Abstract Wear of ultra-high-molecular-weight polyethylene (UHM-WPE) inlays is associated with aseptic loosening in total knee replacement (TKR). The aim of this study was to investigate the in vitro performance of a TKR system that combines several measures to decrease UHMWPE wear. Tests were carried out on a BPK-S Integration system (R&D, P. Brehm Chirurgie-Mechanik, Weisendorf, Germany) according to ISO 14243-1 in a knee joint simulator. Calf serum with a high protein concentration of 30 g/l was chosen as the test lubricant. PE wear was measured gravimetrically. Particle analysis was performed by scanning electron microscopy, with measurement of particle size and shape. Low mean wear rates of 1.20 mg per million cycles were found for the fixed bearing type and 2.47 mg per million cycles for the rotating-platform bearing design. Anteroposterior deflection was low. The contact areas for both types of bearings were large and showed a constant pattern throughout the test. Backside wear was obvious on rotating platforms. Particle analysis revealed equally sized and round-shaped particles in both types of bearings (fixed, 0.35 μm; mobile, 0.32 μm). In conclusion, the combination of design features and surface modifications of the BPK-S integration TKR system leads to low gravimetric UHMWPE wear. Zusammenfassung Abrieb von Ultra-High-Molecular-Weight Polyethylen (UHMWPE) gilt als eine der wesentlichen Ursachen für die aseptische Lockerung von Knieendoprothesen. Das Ziel dieser Studie ist es, das Abriebverhalten eines Knieendoprothesensystems zu untersuchen, welches verschiedene Ansätze zur Abriebsminimierung vereint. Getestet wurde das BPK-S Integration-System der Firma R&D, P. Brehm Chirurgie-Mechanik (Weisendorf, Germany), gemäß ISO 14243-1, in einem Kniesimulator. Es wurde Kälberserum mit einer erhöhten Proteinkonzentration von 30 g/l eingesetzt. Der PE-Abrieb wurde gravimetrisch bestimmt. Die Abriebpartikel wurden mittels Elektronenmikroskopie nach deren Form und Größe analysiert. Es fanden sich insgesamt geringe Abriebraten von 1,2 mg pro 1 Mio. Zyklen beim „fixed bearing”- und 2,47 mg pro 1 Mio. Zyklen beim „mobile bearing”-System. Die a.-p.-Auslenkung war gering. Die femorotibialen Kontaktflächen zeigten bei beiden ultrakongruenten Systemen keine wesentliche Veränderung über den Prüfungszeitraum. An den Inlays des „mobile bearing”-Systems fanden sich Zeichen des „backside wear”. Die Partikelanalyse zeigte vergleichbar große, überwiegend runde Abriebpartikel („fixed”, 0,35 μm; „mobile”, 0,32 μm). Zusammenfassend fand sich als Folge der Oberflächenbehandlung und des Designs des BPK-S Integration-Systems ein sehr geringer gravimetrischer Abrieb im Vergleich zu Angaben über andere, ebenfalls nach ISO 14243-1 gemessene Kniesysteme.

Effects of low concentrated BMP-7 administered by co-cultivation or plasmid transfection on human osteoarthritic chondrocytes.

INTRODUCTIONnWhile BMP-7 has proven to be one of the most potent growth factors in cartilage tissue engineering, protein concentration and route of administration remain a matter of debate. Here we investigated the effects of a low concentration of BMP-7 on human osteoarthritic chondrocytes administered by protein co-cultivation and plasmid transfection.nnnMETHODSnFreshly released (P0) or in vitro propagated chondrocytes (P2) were cultivated in a collagen type-I gel for 3 weeks in vitro or in nude mice. Seeded chondrocytes were treated with 50 ng/mL BMP-7 directly added to the medium or were subject to transient BMP-7 plasmid transfection prior to gel cultivation. Untreated specimens served as a control. After recovery, samples were investigated by histological and immunohistochemical staining and real-time PCR.nnnRESULTSnIn vitro, collagen type-II protein production was enhanced, and it was stored mainly pericellularly. Collagen type-II and aggrecan gene expression were enhanced in both treatment groups. After nude mouse cultivation, col-II protein production was further enhanced, but specimens of the BMP-7 transfection group revealed a clustering of col-II positive cells. Gene expression was strongly upregulated, chondrocyte number was increased and the differentiated phenotype prevailed. In general, freshly released chondrocytes (P0) proved to be superior to chondrocytes pre-amplified in vitro (P2).nnnCONCLUSIONSnBoth BMP-7 co-cultivation and plasmid transfection of human osteoarthritic chondrocytes led to improved cartilage repair tissue. Nevertheless, the col-II distribution following BMP-7 co-cultivation was homogeneous, while samples produced by transient transfection revealed a col-II clustering.

Millicurrent stimulation of human articular chondrocytes cultivated in a collagen type-I gel and of human osteochondral explants

BackgroundHere we investigate the effect of millicurrent treatment on human chondrocytes cultivated in a collagen gel matrix and on human osteochondral explants.MethodsHuman chondrocytes from osteoarthritic knee joints were enzymatically released and transferred into a collagen type-I gel. Osteochondral explants and cell-seeded gel samples were cultivated in-vitro for three weeks. Samples of the verum groups were stimulated every two days by millicurrent treatment (3 mA, sinusoidal signal of 312 Hz amplitude modulated by two super-imposed signals of 0.28 Hz), while control samples remained unaffected. After recovery, collagen type-I, type-II, aggrecan, interleukin-1β, IL-6, TNFα and MMP13 were examined by immunohistochemistry and by real time PCR.ResultsWith regard to the immunostainings 3 D gel samples and osteochondral explants did not show any differences between treatment and control group. The expression of all investigated genes of the 3 D gel samples was elevated following millicurrent treatment. While osteochondral explant gene expression of col-I, col-II and Il-1β was nearly unaffected, aggrecan gene expression was elevated. Following millicurrent treatment, IL-6, TNFα, and MMP13 gene expression decreased. In general, the standard deviations of the gene expression data were high, resulting in rarely significant results.ConclusionsWe conclude that millicurrent stimulation of human osteoarthritic chondrocytes cultivated in a 3 D collagen gel and of osteochondral explants directly influences cell metabolism.

The German Arthroscopy Registry (DART)

AbstractIn Germany, more than 400,000 arthroscopic procedures are performed each year. The DART registry is designed to study the outcome of arthroscopic procedures of the shoulder, hip, knee and ankle joint under everyday clinical circumstances using patient-reported outcome measures (PROMs). DART aims at identifying patient-specific factors correlated with therapy-associated complications and treatment failure and will help study the influence of concurrent joint diseases and procedures. To achieve these tasks, a Web-based remote data entry system will be applied and adapted to the needs of DART. DART will consist of a physician’s and a patient’s form to enter data on the specific disease, surgical procedure, joint-specific outcome, disability and quality of life measured by validated scores up to 5xa0years following surgery. The pool of data will be subjected to further clinical investigations and subgroup analysis. Individual results will be made accessible to the surgeon and the patient. Moreover, public reports will be generated to provide healthcare authorities and insurance companies with information on the effectiveness of arthroscopic surgery. The aim of this article is to present the methodology of the registry.n Level of evidence V.