G. Sohár

Short-Stem Hip Arthroplasty

Total hip arthroplasty has become a remarkably successful operation for treating osteoarthritis in the last half century. The increased need for better quality of life has led the operation to be extended to younger patients. However, long term results showed a rise in the number of revi‐ sion surgeries. The longer life expectancy of the patient population led to the demand for multi‐ ple revision surgeries for the same patient. In revision surgery numerous technical difficulties are encountered because of bone loss due to the loosening. In addition, these solutions are ex‐ ceptionally expensive. The search for alternatives led to the modification of the primary com‐ ponents. Improvements have introduced changes to achieve more proximal load transfer to the femur in order to reduce proximal stress shielding and thus preserve bone stock for poten‐ tial revision surgery. As hip resurfacing declines in popularity, it is likely that there will be a corresponding increase in the number of short stem femoral components in use. Metaphyseal stems combine the advantages of straight stem implant design and hip resurfacing.

Characterization of Live and Experimentally Degenerated Hyaline Cartilage with Thermal Analysis

Osteoarthritis (OA), the most prevalent joint disease, is characterized by the progressive loss of articular cartilage that leads to chronic pain and functional restrictions in affected joints [Goldring & Goldring, 2007]. The prior notion of OA as a bland disease related to aging and “wear and tear” of the joint has given way to views of a dynamic system with multiple pathogenic contributors, as local factors, as well as crystals and inflammation [Brandt et al., 2006]. OA represents a major therapeutic challenge to medical and health-care providers. In part, this is because OA is a chronic condition in which symptoms evolve over long periods of time and in which symptomatic episodes are frequently separated by lengthy asymptomatic periods. It is likely, however, that alterations in joint structure and function continue during these relative periods of clinical quiescence. In addition, limited tools are available for the assessment of the progression of structural changes in joint tissues in association with the development of osteoarthritis. Importantly, the correlation between structural alterations and symptoms is contradictory. There is a significant difference in the expression levels of cartilage relevant molecules between specimens showing histological alterations and control samples [Lorenz et al., 2006]. A total breakdown in synthesis of matrix molecules leads to the end stage OA with further progression of cartilage loss. A number of OA models, e.g. aging animals, genetically modified mice, as well as animals with surgically, enzymatically, or chemically induced OA [van den Berg, 2001] have been developed to investigate the pathogenesis of OA and evaluate the potentials of new disease/structure-modifying drugs [Oegema et al., 2002]. Among these, monosodium iodoacetate (MIA, iodoacetic acid) model has been widely used to analyze the histological and biochemical changes observed during the progression of OA [Ameye, & Young, 2006]. Injection of the metabolic inhibitor, MIA, into joints inhibits glyceraldehye-3-phosphate dehydrogenase activity in chondrocytes, resulting in disruption of glycolysis and eventual cell death [Kalbhen, 1987]. The progressive loss of chondrocytes results in histologic and morphologic changes to the articular cartilage, closely resembling those seen in human OA [Janusz et al., 2001]. In addition, the model has been utilized by a number of investigators to test pharmacologic agents for their ability to preserve cartilage structure [Janusz et al., 2001].

464 PHYSICOCHEMICAL TRANSFORMATIONS DURING THERMAL DEGRADATION OF OSTEOARTHRITC AND RHEUMATOID HYALINE CARTILAGE

Purpose: The aim of this study was to investigate whether cartilage undergoes complex changes in matrix composition (water, proteoglycan, and collagen content) during the late stage of degeneration. These complex deviations from the normal matrix composition are hypothesized to correlate with changes in thermal analysis. Based on previous studies, we hypothesized that thermodynamic findings clearly differentiate normal and Osteoarthritc (OA) and Rheumatoid (RA) human hyaline cartilage and physicochemical transformations may provide information on the role of water content in osteoarthritis. Methods: In order to conduct the thermoanalytical study, 51 samples were collected. During arthroplasty procedures performed at the Orthopedic Department, University of Szeged, 16 OA, 24 RA human hyaline cartilage samples were obtained and normal cartilage from 11 knee. The mean age of the RA patients was 61 years (SD=5.2), of the OA patients was 64 years (SD=5.7) while the average age of the normal group was 64 years (SD=4,2). The state of the hyaline cartilage was determined intraoperatively. After the operation, a disc (5mm in diameter) was removed under sterile conditions and only the remaining full thickness cartilage was used. All tissues were yielded in accordance to legal regulation, international ethical concerns, and patients’ consent. The calorimetric properties of samples were determined by differential scanning calorimetry, samples were heated from 0 to 80 °C. The thermogravimetric analysis was performed with the use of a MOM Derivatograph. These techniques measure net changes in enthalpy and weight as a result of many reactions taking place simultaneously and are particularly useful for indicating the temperature range and the rate of thermal processes as well as giving considerable information on physical and chemical changes. Relatively little has been published on the thermal properties of human hyaline cartilage. Results: It was found, that the average total water content of intact (normal) cartilage is 79.21%, which was probably the interstitial water and the difference was supposedly bound on the surface. To remove the cartilage extracellular water content 41.89 kJ/M energy was needed. Cartilage obtained from RA femoral head had a lower water content of 72.64%. Extraction of the cartilage fluid content needed 53 kJ/M energy. Total water content of the osteoarthritic samples was 84.15%, 49.03 kJ/M energy was used for the removal of the fluid content. With the rise of temperature an endothermic reaction was observed in all of the cases. The enthalpy change of the process initiated by the temperature change showed marked difference between the normal and pathological groups. Conclusions: Characterization of the altered metabolism in cartilage that promotes disease progression should lead to future treatment options that can prevent structural damage. Since damaged articular cartilage has a very limited potential for healing, prevention is fundamental in treatment. However, prevention is not possible without the knowledge of the basic pathomorphological mechanism leading to cartilage degeneration. Further investigation is needed to examine the effectiveness of currently used for resolving cartilage matrix degeneration. Thermal techniques are still developing and many new variants and applications are reported each year. Combined techniques with microscopy or spectroscopic instruments are of obvious value to the pharmaceutical scientist. 465