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Aim: Mesenchymal stem cells have a high therapeutic potential for the reconstruction of articular cartilage defects. In this study, a cartilage-polymer construct using mesenchymal stem cells from trabecular bone and a polylactic acid polymer was fabricated with a press-coating technique. We investigated whether cells from human trabecular bone fragments have the same chondrogenic differentiation potential as mesenchymal stem cells derived from bone marrow and whether it is possible to reconstruct an osteochondral lesion in the nude rat with the fabricated construct., Method: Cells were obtained from the femoral head of patients undergoing total hip arthroplasty. The fabrication of the constructs was performed by centrifugation of 1.5x10(6) cells to a cell pellet which was then placed in a polymer block. The fabricated cell constructs were cultivated for 3 weeks in a serum-free medium, supplemented with transforming growth factor beta1. Every third day, the chondrogenic differentiation was analysed using chondrogenic and osteogenic marker genes. After three weeks the constructs were implanted into 5 mm osteochondral defects of the knee joint of nude rats. After 4 and 12 weeks histochemical and immunohistochemical analyses were performed., Results: At the end of the culture period the constructs showed a proteoglycan-rich extracellular matrix with the expression of collagen types II, IX and X as well as aggrecan und COMP (cartilage oligomeric matrix protein). No osteogenic markers except collagen type I could be detected. The analysis of the in vivo experiment showed a good defect filling with a reconstructed cartilage surface along with increasing resorption of the polymer., Conclusion: We have shown that it is possible to fabricate cartilage-polymer constructs from trabecular bone-derived cells, and that the cells have the same chondrogenic differentiation potential as mesenchymal stem cells derived from bone marrow. With the fabricated cartilage-polymer construct it is possible to reconstruct an osteochondral defect in the knee joint of the nude rat., (Copyright (c) Georg Thieme Verlag KG Stuttgart-New York.)

Aim: The aim of this study was an analysis of the long-term behaviour and implant migration of the Parhofer-Mönch-screw cup seen in patients between 1982 and 1991., Method: 92 cups (m : f = 53 : 39, mean age 53 +/- 7 years) were included mainly prospectively. After 118 +/- 45 months all patients were examined clinically and radiologically. Digital migration analysis was performed using the single-film X-ray analysis (Einbildröntgenanalyse, EBRA)., Results: 5 patients had died. 32 cups were revised, in 7 patients a loosening of the cup was suspected. The 10-year-survival was 71.4 %. In 53 of 81 analysed cups a migration of more than 1 mm was shown, 28 cups did not migrate. In comparison to these stable implants the survival of migrated cups was significantly inferior., Conclusion: The 10-year-survival and the high rate of implant migration document the poor results of the PM cup. In spite of an extraordinary primary stability, the failure of secondary osseointegration represents the main cause of loosening in this type of cup.

Successful osseointegration of an implant depends on the properties of the material of which it is made. A standardized cell culture system for the assessment of the biological effect of material surfaces has already been described. In the present study, this system has been extended to include the quantitative analysis of the material-dependent osteoblast gene expression. Human foetal osteoblasts (hFOB 1.19) were cultured for 3 weeks on titanium surfaces of varying roughness, and on surfaces of chromium-cobalt-molybdenum alloy (CrCoMo). Using a real time RT-PCR technique, expressions of alkaline phosphatase, collagen 1 and osteocalcin were determined as parameters of osteoblast differentiation. In comparison with CrCoMo, differentiation was accelerated on titanium. While the smooth titanium surface leads to earlier cell growth, the rough surface induces more prolonged and stronger cell proliferation. Our results confirm at the molecular level the excellent clinical biocompatibility of titanium surfaces. The real-time RT-PCR provides a new method for the quantitative assessment of material-dependent osteoblastic differentiation.

The effect of titanium-based PVD coatings and a titanium alloy on the proliferation and differentiation of osteoblasts was investigated using a standardised cell culture system. Human fetal osteoblasts (hFOB 1.19) were cultured on titanium-niobium-nitride ([Ti,Nb]N), titanium-niobium-oxy-nitride coatings ([Ti,Nb]ON) and titanium-aluminium-vanadium alloy (Ti6Al4V) for 17 days. Cell culture polystyrene (PS) was used as reference. For the assessment of proliferation, the numbers and viability of the cells were determined, while alkaline phosphatase activity, collagen I and osteocalcin synthesis served as differentiation parameters. On the basis of the cell culture experiments, a cytotoxic effect of the materials can be excluded. In comparison with the other test surfaces, [Ti,Nb]N showed greater cell proliferation. The [Ti,Nb]N coating was associated with the highest level of osteocalcin production, while all other differentiation parameters were identical on all three surfaces. The test system described reveals the influence of PVD coatings on the osteoblast differentiation cycle. The higher oxygen content of the [Ti,Nb]ON surface does not appear to have any positive impact on cell proliferation. The excellent biocompatibility of the PVD coatings is confirmed by in vivo findings. The possible use of these materials in the fields of osteosynthesis and articular surfaces is still under discussion.

The cytotoxicity of Degutan surfaces with different degrees of roughness, and the effect of surface structures on osteoblast proliferation and differentiation, was investigated with standardised cell culture systems. Fibroblast cell lines (BALB/3T3) and osteoblast cell lines (hFOB 1.19) were used. The number and variability of the cells were determined for assessment of proliferation and alkaline phosphatase activity, collagen I and osteocalcin production were used as parameters for differentiation. In the early phase, the largest numbers of cells and greatest proliferation were measured on polished Degutan surfaces. In the late phase, however, larger numbers of cells and a greater degree of proliferation were to be seen on sandblasted and sandblasted/heat-treated Degutan surfaces. No differences were found for collagen I, osteocalcin production or alkaline phosphatase activity. Neither the osteoblasts nor the fibroblasts revealed a toxic effect of Degutan. The results for osteoblast differentiation correlate with recent studies on identical structured titanium surfaces. In view of the immeasurable amount of ion release, Degutan may be considered an ideal model for an inert material surface.

Unlabelled: Tumour necrosis factor (TNF) is considered to be the initiator protein of particle disease leading to aseptic loosening of endoprostheses. The aim of the present study was to investigate the TNF response of the macrophage-like cells (MLC) to the periprosthetic particles typically found during revision surgery. For this purpose, particles of polyethylene (PE), pure titanium (Ti), chromium (Cr), cobalt (Co), alumina ceramic (Al2O3) and zirconium dioxide (ZrO2) were used. Additionally, the therapeutic effect of non-steroidal and steroidal drugs, biphosphonates and pentoxyfylline on PE particles was investigated with the aim of differentiating drugs with, from those without, a positive effect on aseptic loosening., Method: In an established macrophage model (Rader et al. 1999), THP1 cells (human monocytic cell line) were differentiated over a period of five days in the presence of vitamin D3 and GM-CSF in macrophage-like cells (MLC). To obtain a TNF profile of the different materials, 10(6) MLC were incubated with each of a range of different particle concentrations. For drug testing purposes 80 x 10(8) PE particles, which evoked a maximum TNF response, were applied together with increasing drug concentrations in the same manner. The supernatant was then investigated for TNF secretion using ELISA., Results: It was found that the greatest TNF response was provoked by Co and PE particles, and was 25 and 23 times as high, respectively, in comparison with control. The smallest TNF secretion was seen with Al2O3 (4 x control) and ZrO2 (5 x control). At the recommended dose, non-steroidal anti-inflammatory drugs (NSAIDs) produced no decrease in TNF secretion. The biphosphonates, etidronate and ibendronate significantly reduced the TNF response of the PE-stimulated macrophages (by 1/7 and 1/5, respectively). Therapeutic doses of pentoxyfylline also led to a decrease of 1/5 in maximum TNF release., Conclusion: Ceramic articulating surfaces are superior to metal/metal or PE/PE matings in terms of the biological effects of their wear particles. At therapeutic doses, NSAIDs have no beneficial effect on the process of aseptic loosening. Certain biphosphonates and pentoxyfylline have a positive effect on aseptic loosening.

The effect of titanium surfaces with different degrees of roughness on osteoblast proliferation and differentiation was investigated using a standardised cell culture system. Human foetal osteoblasts (hFOB 1.19) were cultured on polished (Ti pol), sandblasted (Ti sb) and sandblasted/heat treated (Ti sb-ht) titanium surfaces for 17 days. Cell culture quality polystyrene (Ps) was used as a control. Cell number and viability were determined for assessment of proliferation. Alkaline phosphatase activity, collagen I and osteocalcin production were measured as parameters for osteoblast differentiation. In the early phase, higher proliferation values were measured on Ti pol. However, on Ti sb and Ti sb-ht higher proliferation was found in the late phase. The activity of the early differentiation marker alkaline phosphatase was higher on Ti pol. No differences were seen for the late differentiation parameters collagen I and osteocalcin. The test system permits the influence of the surface structure on the dynamics of the osteoblast development cycle to be determined. The larger surface area of rough materials leads to an initially delayed, but then prolonged cell proliferation. This model correlates with recent in vivo findings, and confirms the use of rough surfaces for implants in direct contact with bone, even at the cellular level.

The effect of standard orthopaedic materials on proliferation and differentiation of osteoblasts was examined using a standardised cell culture system. Osteoblasts hFOB 1.19 were cultured on stainless steel (SS), a chromium-cobalt-molybdenum alloy (CrCoMb) and commercially pure titanium (cpTi) for 12 days. Cell culture polystyrene (PS) was used as a reference. Cell numbers and cell viability were used as parameters of proliferation. Cell differentiation was assessed using alkaline phosphatase activity, collagen I and osteocalcin production. The parameters of proliferation showed earlier maximum values on PS and cpTi, while proliferation was delayed on SS and CrCoMb. The highest values of differentiation were found on cpTi. The development of alkaline phosphatase activity showed two peaks reflecting apoptosis and redifferentiation. The cell culture system hFOB 1.19 is thus suitable for revealing differences in proliferation and differentiation of osteoblasts on standard orthopaedic materials. The results correlate with previous in vivo findings. Using this system, the dynamic effect of the material surface on the differentiation process of osteoblasts can be demonstrated.

Purpose: Thromboprophylaxis with heparins after total joint replacement is well accepted. The aim of this prospective randomized study was to evaluate the thrombo-prophylactical efficiency of an ankle joint moving device (Artroflow) after total knee arthroplasty., Method: In this prospective study 160 patients were examined who had undergone total knee arthroplasty (TKA). All of the 160 patients received Enoxaparin 1 x 40 mg subcutaneously per day. In addition to this, 90 patients received Artroflow three times a day for 30 minutes. The passive movements of the ankle joint lead to an emptying of the foot and calf veins. Except for the daily routine, we performed physical examination and ultrasound in colour, compression and duplex technique one day before surgery and at the 7th and 14th day after surgery. If a thrombosis was suspected, an ascending phlebography was carried through., Results: The overall thrombosis rate was 6.3% (n = 10). 11.4% (n = 70) deep vein thromboses (DVT) could be observed in the group without Artroflow. Thrombosis occurred in the group with Artroflow in 2 cases (2.2%, n = 90). A statistical difference was found between the two patient groups (p < 0.05, Chi-Square-test). One patient was excluded from the study because of pain in the ankle joint at the fourth day of treatment., Conclusion: In addition to heparins, this ankle joint moving device can be recommended as a physical way to prevent DVTs in the thromboprophylaxis of total knee arthroplasty.

Introduction: Without primary fracture of femoral cortex in femoral head necrosis, 85% of cases have a collapse of the femoral head without treatment after 2 years. It was the aim of this retrospective study to examine the long term outcome of patients having undergone femoral head decompression., Methods: The clinical evaluation was done by the Harris Score. A.p. pictures of the pelvis as well as Lauenstein X-rays were taken as radiographic evaluation. These were compared to the preoperative radiographs, computer-tomographies, szintigrams and MRIs according to the classification of Ficat et al. (1980) and to that of Steinberg et al. (1984)., Results: 62 cases of femoral head necrosis in 52 patients were followed. 12 cases received a varic osteotomy in addition to the decompression of the femoral head. The average follow up period was 90 months postoperatively. 11 cases had received a total hip arthroplasty (THA) and in three cases there was an indication for a THA after follow up examination. The mean interval between femoral head decompression and THA was 7.1 years. 40 cases (65%) ha a Harris Score over 75 points corresponding to a good to excellent clinical result., Conclusion: Femoral head decompression remains an important operation to preserve the structural integrity. It is indicated in cases without subchondral.

Purpose: Aim of this study was the validation of a digital measurement device for hip implants., Methods: From 43 patients with a minimum of four subsequent roentgenograms 246 roentgenograms of PM-shafts (an average 5.72/shaft) and 142 roentgenograms of PM-cups (an average 6.45/cup) were digitized on a DiagnostiX 2048 basis station (Pace Systems, Germany). Modified Sutherland/Nunn methods were chosen for measuring purposes. Regression analysis was done and the results were correlated to implant loosening., Results: Concerning the total vertical migration of the cup there is a significant (p < 0.04) difference between the loosened components (6.02 +/- 2.59 mm) and the fixed cups (2.26 +/- 2.89 mm). The average annual vertical migration rate of the stem shows a highly significant difference (p < 0.007) when comparing loosened stems (0.82 +/- 0.43 mm, total migration 4.78 +/- 2.89 mm) and fixed ones (0.20 +/- 0.54 mm, total migration 1.72 +/- 3.02 mm), Conclusions: Using the regression analysis and a sufficient number of pictures the system allows us to give migration values that make loosening likely. However for the single implant an individual prognosis of loosening is not possible.

For in vitro testing of new biomaterials cultured fibroblasts are employed. In the case of the agar diffusion test survival of cells is involved in the presence of the material to be tested. Further statements on the biological effects of a biomaterial require the use of cell cultures adapted to the tissue concerned and the underlying problem being investigated. In the present study, an osteoblast cell culture system with which implant surfaces in contact with bone can be tested as required by the relevant standards is described. Test bodies made of titanium, polystyrene or copper were used in the conventional agar diffusion test, and were also overgrown with fibroblasts or a cell line of foetal human osteoblasts. For the agar diffusion test, the test criterion was the extent of the inhibition area on staining with neutral red, while for the overgrowth, the mean cell diameter and the number of cells was employed. The phenotype of the osteoblast cell line was determined immunohistochemically by means of alkaline phosphatase or immunohistologically by means of collagen I and osteocalcin. Calcification was demonstrated using the v. Kossa stain. In the case of the osteoblasts, a differentiation of a collagen I and alkaline phosphatase-positive phenotype over an osteocalcin-positive phenotype to an increase in calcium deposition was shown. As in the case of the agar diffusion test, direct overgrowth also revealed no cytotoxic effect for titanium and polystyrene. In contrast, a cytotoxic effect consisting in a decrease in the number of cells and also a left shift in the size distribution was observed for copper. The standard deviations of the individual tests were less for overgrowth than for the agar diffusion test. The culture system for osteoblast cells thus meets the criteria of the EN/DIN 30993-5 in terms of the quality and accuracy of the results obtained. In addition to excluding direct cytotoxicity, this test system offers a new possibility of examining the influence of the material on cell growth. Consequently, it permits a repeatable examination of proliferation and differentiation of the osteoblasts on each material surface.

The principle of photodynamic laser therapy (PDT) for chronic polyarthritis consists in specifically concentrating a drug (photosensitizer) in the synovium. Subsequent activation of the photosensitizer by means of laser leads to a cytotoxic effect. The practicability of PDT was first shown in cell cultures of human synovial fibroblasts. For further tests an animal model consisting of IgG-induced arthritis in rabbits was used. In this model, concentration of the photosensitizer in the synovial lining cells, in the media of arteries and in the lymphoid infiltrate was seen. After laser irradiation there was total selective demarcation of the synovium. In contrast, bradytrophic tissues such as cartilage, meniscus and ligament structures were changed neither macroscopically nor microscopically. In the animal model PDT combines high selectivity with minimal invasiveness and can be used in small joints. PDT thus offers ideal preconditions for future minimal invasive treatment of chronic inflammatory joint diseases.

The aim of this study was the dynamic measurement, with magnetic resonance imaging, of temperature in cartilage irradiated by laser. Fresh specimens, each with chondromalacia grade II and III, were irradiated with a Holmium:YAG laser under MRI control. Temperature was measured by means of the proton-shift method, which allows high temporal and spatial resolution. With this method a maximum increase in temperature of 35 degrees was found after irradiation with 1.0 J and 10 Hz for 5 s at a distance of 1 mm. In no case at all was an increase in temperature of more than 10 degrees observed in the cartilage adjacent to the subchondral bone. These results exclude the possibility of significant thermal damage from laser treatment as described.

Since ten years different laser systems have been used in arthroscopic procedures and percutaneous laser disc decompression. A potential mutagenic risk has not been excluded yet. From photobiology it is known that light in the UV-range is the main source of mutations. Therefore the aim of our study was to determine the mutagenic risk of laser systems at UV-wavelengths. The BALB/3T3 cell line was irradiated at the Excimer wavelengths 248 nm and 308 nm. Transformation rates were compared with non-irradiated cells and the effect of 1 Gy-Roentgen irradiation. Pulse energy, frequency and irradiation time were varied over a broad range. The effect of double irradiation was also examined. For 308 nm no significant transformation rate was found (p < 0.18). In contrast 248 nm showed a highly significant transformation rate (p < 10(-9). Transformation rate after Roentgen irradiation exceeded that of the negative control about two orders. While a certain mutagenic risk exists for 248 nm application of the wavelength 308 nm seems harmless. Our data therefore represent an essential contribution to long term laser safety both for the physician and his patient.

Because of pigmented villonodular synovitis (PVS) 17 of 14,500 knee operations were accomplished at our institute between 1975 and 1993. Diffuse PVS (DPVS) was observed in 7 patients, local PVS (LPVS) in 9 patients; in 1 case LPVS was diagnosed on both joints. 15 knees could be examined 4.8 years after first surgery. 3 recurrences (42.9%) were found in the group of DPVS. In the group of LPVS no recurrent tumor growing was observed. It is demonstrated that partial arthroscopic synovectomy is a sufficient therapy in LPVS. The recurrence rate of DPVS ranges from 8 to 50%, the mean recurrence rate described in literature is 31.3%. Neither arthroscopic nor open synovectomy lead to a complete healing of DPVS. Recurrent arthroscopic synovectomy and regular clinical examination using sonography and particular MRI are the best therapeutical concepts in DPVS.

Fc gamma-receptor-(CD16-)positive natural killer (NK) cells are activated by rheumatoid factor in the synovial fluid of patients with rheumatoid arthritis. This activation induces modulation of the CD16 molecule and release of IFN gamma and TNF alpha by NK cells.