Objective. Hypertrophic chondrocyte differentiation is a key step in endochondral ossification that produces basic calcium phosphates (BCPs). Although chondrocyte hypertrophy has been associated with osteoarthritis (OA), chondrocalcinosis has been considered an irregular event and linked mainly to calcium pyrophosphate dihydrate (CPPD) deposition. The aim of this study was to determine the prevalence and composition of calcium crystals in human OA and analyze their relationship to disease severity and markers of chondrocyte hypertrophy.Methods. One hundred twenty patients with endstage OA undergoing total knee replacement were prospectively evaluated. Cartilage calcification was studied by conventional x-ray radiography, digital-contact radiography (DCR), field-emission scanning electron microscopy (FE-SEM), and synovial fluid analysis. Cartilage calcification findings were correlated with scores of knee function as well as histologic changes and chondrocyte hypertrophy as analyzed in vitro.Results. DCR revealed mineralization in all cartilage specimens. Its extent correlated significantly with the Hospital for Special Surgery knee score but not with age. FE-SEM analysis showed that BCPs, rather than CPPD, were the prominent minerals. On histologic analysis, it was observed that mineralization correlated with the expression of type X collagen, a marker of chondrocyte hypertrophy. Moreover, there was a strong correlation between the extent of mineralization in vivo and the ability of chondrocytes to produce BCPs in vitro. The induction of hypertrophy in healthy human chondrocytes resulted in a prominent mineralization of the extracellular matrix.Conclusion. These results indicate that mineralization of articular cartilage by BCP is an indissociable process of OA and does not characterize a specific subset of the disease, which has important consequences in the development of therapeutic strategies for patients with OA.Osteoarthritis (OA) is the most common joint disorder and is characterized by cartilage loss, new bone formation at the margins of the joints (osteophytes), changes in subchondral bone, and recurrent synovitis. The incidence of OA increases with age. Calcium pyrophosphate dihydrate (CPPD) crystals are known to cause acute attacks of pseudogout in the joints, but crystal deposition has also been reported to be associated with OA (1). Aside from CPPD crystals, basic calcium phosphates (BCPs), such as carbonatesubstituted hydroxyapatite (HA), tricalcium phosphate, and octacalcium phosphate, have been found in the synovial fluid (SF), synovium, and cartilage from patients with OA (2-4). The data concerning the distribution and frequency of their occurrence vary, depending on patient selection and crystal identification methods (5-7). Identification of BCP crystals in OA

BackgroundThe aim of this study was to examine the frequency of articular cartilage calcification in patients with end-stage hip OA. Further, its impact on the clinical situation and the OA severity are analyzed.MethodsEighty patients with OA of the hip who consecutively underwent total hip replacement were prospectively evaluated, and 10 controls were included. The patients' X-rays were analyzed for the presence of articular cartilage mineralization. A Harris Hip Score (HHS) was preoperatively calculated for every patient.Slab specimens from the femoral head of bone and cartilage and an additional square centimeter of articular cartilage from the main chondral defect were obtained from each patient for analysis of mineralization by digital contact radiography (DCR). Histological grading was also performed. In a subset of 20 patients, minerals were characterized with an electron microscope (FE-SEM).ResultsCalcifications were seen in all OA cartilage and slab specimens using DCR, while preoperative X-rays revealed calcification in only 17.5%. None of the control cartilage specimens showed mineralization. There was a highly significant inverse correlation between articular cartilage calcification and preoperative HHS. Histological OA grade correlated positively with the amount of matrix calcification. FE-SEM analysis revealed basic calcium phosphate (BCP) as the predominant mineral; CPPD crystals were found in only two patients.ConclusionsArticular cartilage calcification is a common event in osteoarthritis of the hip. The amount of calcification correlates with clinical symptoms and histological OA grade.

We retrospectively analysed the course of 42 out of 45 patients suffering from different chondrosarcomas which were treated surgically. We found a prospective 5- and 10-year survival of 64% for both time intervals. Follow-up examination was possible in 21 of 45 patients. Most of them were staged as NED, one as AWD, and 8 of 45 were lost to follow-up. From 16 dead patients 12 died of the disease and 4 of unknown but not to tumor related reasons. Survival was depending significantly on the histopathological grade, and the stage according to Enneking's surgical staging system. Eleven out of forty-five patients developed metastases within a mean period of twelve months after surgery. The survival of these patients was significantly reduced. Patients with centrally located tumors exhibited a distinct but non-significant worse survival than those suffering from peripheral tumors. In 18% (8 of 45) recurrence of the tumor was evident within a mean period of 24 months (5-85). Functional evaluation was performed in 21 out of 28 alive patients. After a mean follow-up time of 72 months the mean score was 64% (23-100). Females exhibited a distinct but non-significant better result, the same was observed for peripheral locations compared to centrally located tumors. Regarding age, grade, and line of resection no tendency of any dependence was detected, but worst results were seen in those with a stage III tumor and dedifferentiated CS.