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Background Limited-incision total hip arthroplasty (THA) preserves hip abductors, posterior capsule, and external rotators potentially diminishing dislocation risk. However, potential complications also exist, such as component malposition. Specific implants have been manufactured that enhance compatibility with this technique, while preserving metaphyseal bone; however, little data exists documenting early complications and component position. The purpose was to evaluate primary THA using a curved, bone-sparing stem inserted through the anterior approach with respect to component alignment and early complications. Methods In a retrospective analysis of 108 cases, the surgical technique was outlined and the occurrence of intraoperative fractures, postoperative dislocations, infection, and limb length inequality was determined. Femoral stem and acetabular cup alignment was quantified using the initial postoperative radiographs. Patient follow-up averaged 12.9 (range 2 to 36) months. Results There were eight (7.4 %) complications requiring revision surgery in three (2.8 %) patients with three (2.8 %) infections and three (2.8 %) dislocations. Intraoperative complications included one calcar fracture above the lesser trochanter. Leg length inequality >5 mm was present in three (2.8 %) patients. Radiographic analysis showed that femoral neutral alignment was achieved in 95 hips (88.0 %). All femoral stems demonstrated satisfactory fit and fill and no evidence of subsidence, osteolysis, or loosening. An average abduction angle of 44.8° (±5.3) and average cup anteversion of 16.2° (±4.2) were also noted. Conclusions Although the technique with this implant and approach is promising, it does not appear to offer important advantages over standard techniques. However, the findings merit further, long-term study.

Minimally invasive total hip arthroplasty (THA) has been performed at Saint Louis University School of Medicine since 2000. This study is a critical appraisal of the early outcomes and complications observed in a series of the first 250 consecutive total hip arthroplasty procedures using the Zimmer MIS 2-Incision technique (MIS-2). Despite some published reports indicating high complication rates with this technique, our experience indicates that the complication rates are lower than many series using traditional hip exposures. Our findings show that the MIS-2 technique is useful and need not be restricted to younger patients with a small body habitus. Evolutionary improvements in the surgical technique and pitfalls of the procedure are discussed. Despite its demonstrated advantages, MIS-2 THA remains a challenging technical alteration from traditional total hip operative methods.

DNA methylation constitutes the most stable type of epigenetic modifications modulating the transcriptional plasticity of mammalian genomes. Using bisulfite DNA sequencing, we report high-resolution methylation reference profiles of human chromosomes 6, 20 and 22, providing a resource of about 1.9 million CpG methylation values derived from 12 different tissues. Analysis of 6 annotation categories, revealed evolutionary conserved regions to be the predominant sites for differential DNA methylation and a core region surrounding the transcriptional start site as informative surrogate for promoter methylation. We find 17% of the 873 analyzed genes differentially methylated in their 5′-untranslated regions (5′-UTR) and about one third of the differentially methylated 5′-UTRs to be inversely correlated with transcription. While our study was controlled for factors reported to affect DNA methylation such as sex and age, we did not find any significant attributable effects. Our data suggest DNA methylation to be ontogenetically more stable than previously thought.

Although the pericellular matrix (PCM) plays a central role in the communication between chondrocytes and extracellular matrix, its composition is largely unknown. In this study, the PCM was investigated with a proteomic approach using chondrons, which are enzymatically isolated constructs including the chondrocyte and its surrounding PCM. Chondrons and chondrocytes alone were isolated from human articular cartilage. Proteins extracted from chondrons and chondrocytes were used for two-dimensional electrophoresis. Protein spots were quantitatively compared between chondron and chondrocyte gels. Cellular proteins, which had similar density between chondron and chondrocyte gels, did not proceed for analysis. Since chondrons only differ from chondrocytes in association of the PCM, protein spots in the chondron gels that had higher quantity than that in the chondrocyte gels were selected as candidates of the PCM components and processed for mass spectrometry. Among 15 identified peptides, several were fragments of the three type VI collagen chains (α-1, α-2, and α-3). Other identified PCM proteins included triosephosphate isomerase, transforming growth factor-β induced protein, peroxiredoxin-4, ADAM (A disintegrin and metalloproteinases) 28, and latent-transforming growth factor beta-binding protein-2. These PCM components were verified with immunohisto(cyto)chemistry for localization in the PCM region of articular cartilage. The abundance of type VI collagen in the PCM emphasizes its importance to the microenvironment of chondrocytes. Several proteins were localized in the PCM of chondrocytes for the first time and that warrants further investigation for their functions in cartilage biology.

This study was designed to quantify the role of the pericellular matrix (PCM) in chondrocyte apoptosis using chondrons, which are a cartilage functional unit including a chondrocyte and its associated PCM.Chondrocytes and chondrons were enzymatically isolated from human articular cartilage and exposed to monosodium iodoacetate (MIA) and staurosporine for apoptosis induction. Chondrons were defined by the presence of type VI collagen, a basic component of the PCM. Apoptosis of chondrocytes and chondrons was measured with annexin V binding by flow cytometry and verified with terminal dUTP nick end-labeling staining. In a separate experiment, isolated chondrocytes were treated with soluble type VI collagen, before or after apoptosis induction with MIA, and cell death was measured by the activity of LDH and terminal dUTP nick end-labeling staining.Chondrocytes treated with MIA incurred 27% cell death, compared with 12% in chondrons. On treating with MIA, 9% of chondrocytes underwent apoptosis, compared with only 1.6% of chondrons. Similarly, staurosporine induced 13% apoptosis in chondrocytes, whereas it was 3% in chondrons. Preincubation of type VI collagen effectively prevented chondrocytes from MIA-induced cell death. After apoptosis was induced with MIA, however, treatment with type VI collagen failed to rescue chondrocytes from death.The PCM, a native microenvironment of chondrocytes, protects chondrocytes from apoptosis. Type VI collagen is a functional component of the PCM that contributes to the survival of chondrocytes.

One of the major obstacles hindering cartilage repair is the integration of the reparative cartilage with the recipient cartilage. The purpose of this study was to develop an in vitro model that can be conveniently applied to simulate and improve the integration of tissue engineered cartilage with native articular cartilage. This model, a cartilage integration construct, consists of a cartilage explant and isolated chondrocytes. The explant was anchored to agarose gel on a culture plate as agarose gelation at 4 degrees C to seal the gap between the bottom of the explant and culture plate surface. Isolated chondrocytes were added and confined in the defect created in the center of the explant. After 4 weeks of culture, neocartilage containing proteoglycans and type II collagen was formed. Minimal integration occurred between the neocartilage and the cartilage explant, resembling the failure of cartilage integration manifested in experimental and clinical cartilage repair. In this model, agarose gel anchors the explant onto culture plate by altering temperatures and effectively prevents "leakage" of the isolated chondrocytes from the defect of the explant. This model provides a convenient simulation of the cartilage integration process in vitro and has applications in studies of cartilage integration and cartilage tissue engineering.

Orthopedics, as a specialty, is traced back to 1741, when Nicholas Andre coined the term “orthopaedic” from the Greek words orthos (meaning straight, or free from deformity) and paedia (meaning child). His book, entitled L’Orthopaedie, describes the recognition of deformity and ways in which these deformities could be prevented (1). No invasive surgical procedures were described for treatment of musculoskeletal disease. There were external remedies, various ingested remedies, and some descriptions of manipulations. It was not until the work of Lister, in the 19th century, and the understanding of the importance of asepsis, that orthopedic implants were accepted as a technique in the management of orthopedic diseases.

Minimally invasive total hip arthroplasty is used to describe both newer surgical approaches or simply smaller than standard incisions for the implantation of artificial hip joints. These new techniques have created interest, misunderstanding and controversy for patients and physicians. However, early indications are that minimally invasive hip surgery is an improvement compared to traditional surgery. Lack of purpose-specific equipment and the need to learn new operative skills are factors that may slow the acceptance of these techniques.

The title compound, poly[[aquazinc(II)]-mu-benzene-1,3-dicarboxylato-O1:O1':O2], [Zn(C8H4O4)(H2O)]n, forms a metal-organic coordination network that consists of tetrahedral Zn atoms bonded to one water molecule and three carboxylate groups. Isophthalate groups bridge the four-coordinate Zn centers to generate two-dimensional architectures in the ac plane. These planar zinc isophthalate motifs are linked by infinite C=O...H-O-H interactions along the a axis to form a chiral framework. The observed polar structural pattern originates due to the distorted tetrahedral Zn centers [O-Zn-O 100.7 (2)-136.0 (1) degrees ] and the alignment of the water molecules. Bridging isophthalate groups align to form approximate centrosymmetric motifs.