Effects of celecoxib on the expression of osteoprotegerin, energy metabolism and cell viability in cultured human osteoblastic cells.

BACKGROUND AND OBJECTIVE: The selective COX-2 inhibitor celecoxib is widely used to treat pain and inflammation in rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. The drug has well-known important effects on immune cells but its direct and/or indirect influence on osteoblasts has not yet been explored in detail. This study aimed to investigate the dose-dependent effects of celecoxib on cell viability, energy metabolism and bone remodeling processes in cultured human osteoblastic cells. METHODS: Primary human osteoblasts and MG-63 cells were incubated with celecoxib (2, 10, 50microM). Cell viability and apoptosis were determined by trypan blue, 7AAD and Annexin-V staining. Effects on cellular oxygen consumption were measured amperometrically using a Clark electrode. mRNA expression of GLUT-1 and OPG was determined by RT-PCR; OPG protein secretion by ELISA and HIF-1alpha protein expression by immunoblotting. RESULTS: While celecoxib at a concentration of 2 and 10microM showed only marginal effects, a suprapharmacological concentration of 50microM influenced viability and energy metabolism, as well as OPG expression and secretion of osteoblastic cells. Cell viability was significantly reduced by celecoxib treatment. Celecoxib at 50microM stimulated oxygen consumption significantly. Corresponding experiments with the protonophore FCCP suggest that this effect is due to mitochondrial uncoupling. After 24h, GLUT-1 mRNA expression was significantly increased. HIF-1alpha protein was not expressed under any of our experimental conditions. We also showed that celecoxib at 50microM significantly inhibits OPG protein secretion leading to a compensative increase of mRNA expression. CONCLUSION: Pronounced effects of celecoxib on cell viability (reduction), oxygen consumption (stimulation), GLUT-1 mRNA expression (stimulation) and OPG protein secretion (inhibition) in osteoblastic cells were observed only at 50microM-a concentration not reached by therapeutic doses giving plasma concentrations less than 10microM. On the contrary, celecoxib at 2 and 10microM showed only marginal effects, suggesting that celecoxib administration is probably safe with respect to bone metabolism in cases requiring potent treatment of pain and inflammation. However, higher intracellular concentrations, which might occur through accumulation, necessitate investigations with high concentrations.

[C-reactive protein. An independent risk factor for the development of infection after primary arthroplasty]. / Das C-reaktive Protein. Ein unabhängiger Risikofaktor für die Entwicklung eines Infekts nach Primärendoprothetik.

BACKGROUND: Infection is a severe complication after primary arthroplasty of the hip (THA) or knee joint (TKA). Based on its high sensitivity, the C-reactive protein (CRP) concentration has become a valuable tool in the diagnosis of infection, although it has only moderate specificity. Because of this, it remains unclear whether a preoperative increased CRP without clinical symptoms is a risk factor for infection after primary arthroplasty. MATERIAL AND METHODS: In a retrospective analysis, we investigated individuals with infection after primary THA or TKA and matched them with patients without infection after similar operations. Matching criteria were age, gender, and present diseases. The average age of the 50 included individuals was 67.4 (range 48-81) years, with eight men and 17 women in each group. In addition to preoperative CRP, specific patient and surgery data and microbiological and histopathologic findings were obtained. RESULTS: The average preoperative CRP concentration in the infected patient group was 1.3+/-2.5 mg/dl, in contrast to 0.4+/-0.7 mg/dl in the noninfected group. A threshold of 0.5 mg/dl was appropriate for discriminating between the two groups [13/25 (52%) in the infection group vs. 3/25 (12%) in the control group, p=0.003]. Independent from the patient group, CRP concentrations were significantly increased in individuals with diabetes mellitus (1.2+/-1.5 vs. 0.7+/-2.0 mg/dl, p=0.03). CONCLUSION: An increased preoperative CRP concentration without clinical findings of infection is a risk factor for prosthetic infection after primary THA or TKA with a threshold concentration of 0.5 mg/dl. Latent local or systemic infections or aseptic inflammation with subsequent local immune suppression seem to be responsible. We recommend evaluating CRP before every THA and TKA. For values beyond 0.5 mg/dl, an exploration for infection should be done. Otherwise, the patient should be informed about the increased risk of infection.

[Influence of adjuvant pain medication on quality of life in the treatment of postmenopausal osteoporosis]. / Einfluss der adjuvanten Schmerztherapie in der Behandlung der postmenopausalen Osteoporose auf die Lebensqualität.

AIM OF THE STUDY: Chronic pain is the main symptom of postmenopausal osteoporosis. This can decrease mobility and quality of life of the patients. The hypothesis of this study was that administration of an adjuvant pain medication is essential additionally to the basic therapy. The second question was if a recommendation can be formulated whether a peripheral or a central acting pain medication is more effective to prevent osteoporosis induced chronic pain. METHODS: Three pseudorandomised patient groups were prospectively compared. Group 1 was treated with alendronate, vitamin D, and calcium. Group 2 also received ibuprofen, and group 3 also received tramadol. In 117 women suffering from postmenopausal osteoporosis, quality of life was measured before and 26 weeks after therapy using the International Osteoporosis Foundation Qualeffo-41 score, and pain intensity was measured using a visual analogue scale. RESULTS: No therapy-associated complications were observed during the study. After 26 weeks, quality of life significantly increased in groups 2 and 3 compared with group 1 (p<0.001). Pain intensity decreased in group 1 by only 6 points, whereas it decreased in group 2 by 31 points and in group 3 by 24 points. Pain relief was significantly different between the treatment groups and the control group and between the treatment groups themselves (p<0.001 and p<0.01). CONCLUSION: We conclude that pain therapy with an almost peripherally acting drug such as ibuprofen can reduce osteoporosis-associated chronic pain better than a centrally acting pain medication such as tramadol. It therefore can be recommended to prescribe ibuprofen rather than tramadol for treating osteoporosis-associated chronic pain in postmenopausal women if the specific risk for gastrointestinal side effects is considered.

[Promotion of bone healing through clinical application of autologous periosteum derived stem cells in a case of atrophic non-union]. / Klinische Anwendung von autologen Periostzellen zur Förderung der Knochenheilung bei atropher Pseudarthrose--Kasuistik.

This case report describes the application of periosteum-derived mesenchymal stem cells in a patient with atrophic non-union of the distal femur after correction osteotomy. While biomechanical treatment devices for various bone defects are available in abundance, biological promoters for clinical application in situations of critical bone healing are still scarce. We showed radiographically that cultivated autologous periosteal bone precursor cells on a three-dimensional matrix can promote bone healing in a defect where numerous established methods had failed to lead to consolidation. To the best of our knowledge, this is the first clinical application of in-vitro cultivated autologous periosteum-derived cells for the healing of a large bone defect in humans.

[Reconstruction of the extensor mechanism using a free, allogenic, freeze-dried patellar graft]. / Rekonstruktion des Streckapparats mittels freiem, allogenem, gefriergetrocknetem Patellatransplantat.

Allograft reconstruction of a deficient extensor mechanism is sufficient using an allogenic, freeze-dried patellar graft sterilized with peracetic acid. The reduced risk of infection is an advantage over fresh-frozen grafts.

Effects of dexamethasone and celecoxib on calcium homeostasis and expression of cyclooxygenase-2 mRNA in MG-63 human osteosarcoma cells.

OBJECTIVE: Glucocorticoids and selective COX-2 inhibitors are potent anti-inflammatory agents. They are also suggested to influence bone physiology and remodeling. Here we searched for effects of dexamethasone and celecoxib on crucial parameters of bone physiology that could be therapeutically relevant. METHODS: The human osteosarcoma cell line MG-63 was used to measure effects of these drugs on (i) intracellular calcium concentration ([Ca2+]i) using a microfluorometric technique, (ii) alkaline phosphatase and osteocalcin levels (EIA) and (iii) the expression of cox-2 mRNA (quantitative real time PCR). Measurements were performed in Vitamine D-incubated quiescent cells and in cells stimulated with TNF-alpha and IL-1beta. RESULTS: We found the cytokine-stimulation to increase [Ca2+]i which was prevented by dexamethasone already after 30 min and still after 48 h. Dexamethasone was without any effect on [Ca2+]i in quiescent cells. Celecoxib had no measurable short-term or long-term effects neither in quiescent nor in stimulated cells. Vitamin D stimulated the expression of cox-2 mRNA which was further enhanced by TNF-alpha/IL-1beta. Dexamethasone did not have any measurable effects on COX-2 expression after 30 min, but a pronounced inhibition was seen after 48 h. In contrast, celecoxib had no effect on COX-2 expression. Neither of the drugs had any effect on the secretion of alkaline phosphatase and osteocalcin. CONCLUSION: We found dexamethasone to inhibit the [Ca2+]i increase in MG-63 cells following stimulation and to reduce considerably COX-2 expression via the genomic pathway. In contrast, celecoxib did not show any measurable short-term or long-term effects on the parameters of bone physiology measured.

[Accuracy of determination of the hip centre in navigated total knee arthroplasty]. / Genauigkeit der Bestimmung des Hüftgelenkszentrums bei der Kniegelenksnavigation.

AIM: In navigated knee arthroplasty the hip centre is determined by rotary motion of the femur (pivoting). The accuracy of this functional hip centre determination in vivo is unclear. In the following paper the accuracy of pivoting in the determination of the hip centre was examined. METHODS: Navigated (TC-PLUS, Solution, PLUS Orthopedics) total knee arthroplasty (PI Galileo, PLUS Orthopedics) was performed on 25 patients with primary arthritis of the knee joint. The position of the femoral component and the hip centre were postoperatively determined by computer tomography. Through comparison with the intraoperatively documented data, the deviation of the pivoted from the true hip centre in the frontal and sagittal planes was calculated. The degree of arthritis of the hip was determined on plain radiographs according to Kellgren. RESULTS: The mean deviation was determined to 1.0 +/- 0.7 degrees in the frontal plane and 2.5 +/- 1.6 degrees in the sagittal plane (p = 0.002). This corresponds to a mean overall deviation of 20 +/- 10 mm. The data were continuously, non-parametrically distributed without any outliers. A great range of motion (ROM) in the frontal as well as sagittal planes during pivoting resulted in a less accurate determination of the hip centre. There was no correlation to the degree of arthritis of the hip. CONCLUSION: The results indicate a recommendable ROM during pivoting for maximal accuracy of hip centre determination of 20 to 30 degrees in the sagittal plane and 30 to 40 degrees in the frontal plane. Arthritis of the hip is not a contraindication for functional determination of the hip centre.

[Reduction of arthrosis associated knee pain through a single intra-articular injection of synthetic hyaluronic acid]. / Die einmalige intraartikuläre Injektion eines synthetischen Hyaluronsäurepräparates reduziert arthroseassoziierte Kniegelenkschmerzen.

AIM: Conventional hyaluronic acids need three to five injections for therapeutic success, whereas Durolane), a synthetic hyaluronic acid, needs only a single injection. Clinical outcome using Durolane should be compared with the results of studies using hyaluronic acids or glucocorticoids. METHOD: Fifty patients with primary gonarthrosis stages I-III (Kellgren Score) were investigated for knee function, pain intensity, and quality of life. The knee and osteoarthritis outcome score (KOOS), visual analogue scale (VAS), and European quality of live score (EQ-5D), as well as motion of the knee were measured. Patients were investigated before, and 2, and 24 weeks after injection. RESULTS: Two weeks after injection, the subjective function of knee and quality of life had increased significantly. In the following 22 weeks, all parameters increased significantly (quality of life and activity +19%; range of motion active 109 vs. 115 degrees ; pain, 55 vs. 41 mm (VAS); all p<0.01). CONCLUSION: We conclude that a single injection of Durolane can reduce arthrosis associated knee pain sufficiently. Our data are comparable with those published in clinical studies using other hyaluronic acids. The effects of Durolane are delayed but more sustained compared than those found for glucocorticoids. Because of the single injection, we see an advantage in using Durolane compared to other conventional hyaluronic acids and glucocorticoids.

[Variance of identification of femoral epicondyles in navigated total knee arthroplasty]. / Varianz der Epikondylenerfassung bei der navigierten Knieendoprothesenimplantation.

BACKGROUND: The aims of this study were the quantification of the accuracy of registration of the epicondylar axis (EA) in navigated total knee arthroplasty (TKA) and the identification of presumed factors influencing this accuracy. METHODS: A total of 32 navigated TKAs were performed and the surgical EA registered. Postoperatively, the difference from the surgical EA determined by computed tomography was calculated. Presumed factors influencing the accuracy were sex, preoperative malalignment, stability and range of motion, operated side, body mass index, and component size. RESULTS: The absolute error was calculated to be 1.4+/-1.3 degrees . Alignment according to the intraoperatively defined axes would have resulted in three outliers (>3 degrees malalignment). The operated side was the only factor showing a significant effect on the accuracy. The absolute error in left knee joints was calculated to be 0.9+/-0.7 degrees (max. 2.4 degrees ) and in right knee joints to be 2.0+/-1.5 degrees (max. 5 degrees, p=0.021). CONCLUSIONS: The surgeon stood on the patient's right side in every case, so that right knee joints were operated from the lateral and left ones from the medial side. A medial position of the surgeon to the knee joint during registration of EA is recommended because it results in a higher accuracy than a lateral position.

Altered cartilage mechanics and histology in knee osteoarthritis: relation to clinical assessment (ICRS Grade).

OBJECTIVE: Substantial changes in articular cartilage composition and mechanical properties occur during the development of osteoarthritis (OA). While softening in the initial stage is reported and sometimes used as an indicator of early OA, there is a lack of data relating the macroscopic appearance of cartilage to its mechanical and histological properties in all stages of degeneration. Knowledge about the mechanical quality of the tissue is important for diagnostic reasons and the understanding of the development of OA. DESIGN: The cartilage areas of 21 osteoarthritic human cadaver tibia plateaus were classified using the International Cartilage Repair Society (ICRS) system. A material testing device determined the Young's modulus of the cartilage by unconfined compression. Histological analysis used haematoxylin and eosin staining and Safranin-O staining for the evaluation of the Mankin score. RESULTS: A correlation between increasing ICRS Grade and stiffness reduction was found (R2=0.69). Stiffness values were for ICRS Grades 1, 2 and 3: E1=0.50+/-0.14 MPa, E2=0.37+/-0.13 MPa and E3=0.28+/-0.12 MPa, respectively. The histological evaluation confirmed the ICRS classification (R2=0.74). A moderate correlation between Mankin score and cartilage stiffness was observed (R2=0.47). CONCLUSIONS: The results indicate a relation between structural, mechanical and histological changes in all stages of the degeneration. With increasing ICRS Grade the cartilage stiffness, which is primarily influenced by the integrity of the extracellular matrix, decreases. Therefore, methods of stiffness determination such as indentation may be used to characterize cartilage in all stages of OA. However, the data suggest that differentiating between healthy cartilage and ICRS Grade 1 may be difficult using mechanical testing alone.

Endothelin-1 is secreted after total knee arthroplasty regardless of the use of a tourniquet.

Early infections and wound healing disorders after implantation of a total knee replacement occur regardless of the intraoperative use of a tourniquet. The biochemical regulatory processes responsible for the disturbances in microcirculation and thus the potential therapeutic options have yet to be elucidated. The hypothesis of the present paper was that endothelin-1 (ET-1), a mediator of microcirculation disturbances in parenchymatous organs, also is released after major operations on peripheral joints. The concentration of ET-1 in the plasma was determined preoperatively and at 10 postoperative time points (5 min-48 h) with (group A, n=10) and without the use of a tourniquet (group B, n=10). The ET-1 concentration achieved its maximum 6h after opening the tourniquet, which corresponded to 3.3 times the preoperative value. Without a tourniquet, the concentration maximum (2.9 times the baseline value) was achieved already 1.5 h after the end of the operation. However, the total amount of ET-1 secreted over 24 h was identical in both groups (p>0.5). We conclude that the tissue hypoxia resulting from the use of a tourniquet modulates ET-1 secretion, but that traumatization during the operation has a much stronger influence on the total amount secreted. ET-1 antagonists thus should be discussed for the drug prophylaxis of wound healing disorders, regardless of the use of a tourniquet.