Cartilage oligomeric matrix protein enhances osteogenesis by directly binding and activating bone morphogenetic protein-2.

Bone morphogenetic proteins (BMPs) are effective for bone regeneration, and are used clinically. However, supraphysiological doses are required, which limits their use. Cartilage oligomeric matrix protein is an extracellular matrix protein, which we have previously shown can bind to growth factors of the TGFs family, suggesting that COMP may also bind to BMP-2.

Diagnosis of periprosthetic joint infections of the hip and knee.

No preferred test for diagnosis of periprosthetic joint infection exists, and the algorithm for the workup of patients suspected of infection remains unclear. The work group evaluated the available literature to determine the role of each diagnostic modality and devise a practical algorithm that allows physicians to reach diagnosis of periprosthetic joint infection. Ten of the 15 recommendations have strong or moderate evidence in support.

Estrogen and osteoarthritis.

In menopausal women and the elderly, populations most often affected by osteoarthritis (OA), estrogen levels are lower than normal, which suggests that estrogen may be an important regulator of OA. Estrogen can influence chondrocyte function on multiple levels by interacting with cellular growth factors, adhesion molecules, and cytokines. Nevertheless, findings regarding a correlation between estrogen and OA are inconsistent and inconclusive and range from estrogen protecting against OA to cartilage damage mediated by high levels of estrogen and higher binding to estrogen receptors.

Recent advances toward the clinical application of bone morphogenetic proteins in bone and cartilage repair.

Inefficient healing of bony and cartilaginous defects is a common situation encountered by orthopedic surgeons. Enhancing the regenerative potential of bone and articular cartilage has the potential for profound applications in treatment of nonunions, large segmental bone and cartilage defects, and arthritis. The bone morphogenetic proteins (BMPs) encode a highly conserved class of signaling factors that possess the ability to induce ectopic cartilage and bone formation in vivo.

Duplex ultrasonography in patients suspected of postoperative pulmonary embolism following total joint arthroplasty.

Duplex ultrasonography of the deep venous system of the lower extremities is often utilized in the diagnostic evaluation of total hip and knee arthroplasty patients suspected of pulmonary embolism in an attempt to identify the embolic source. A retrospective review of 135 patients who were clinically suspected of pulmonary embolism after 71 total knee arthroplasties and 64 total hip arthroplasties was performed. Of the 35 patients diagnosed with pulmonary embolism, 2 (5.

Instability following total hip arthroplasty.

Dislocation is the second most common complication of total hip arthroplasty. Most dislocations occur early in the postoperative period and are caused by patient factors, surgical factors, or a combination of both. Patient factors that predispose to postoperative dislocation include previous surgery and neurologic impairment.

[Effects of bone morphogenetic protein-2 on cartilage oligomeric matrix protein expression in chondrocytes].

Objective: To quantitatively evaluate the effects of BMP-2 on the COMP gene expression in both primary human chondrocytes and chondrogenic cell line ATDC55.

Methods: Human adult and fetal chondrocytes were stimulated by BMP-2. The COMP gene expression level was analyzed by real time reverse transcription-PCR assay and normalized to a reference mRNA (GAPDH).

Revision of polyethylene acetabular liners with a cemented polyethylene cup: a laboratory study.

Various technique parameters for the revision of failed polyethylene acetabular liners using a cemented polyethylene cup were evaluated in this laboratory study. The effects of cement mantle thickness and roughening the inner surface of the shell or outer surface of the cup were determined by measuring cup dissociation strength from the metal shell after cyclic loading of the cup. The use of a cement mantle thickness of 2 to 4 mm provided dissociation strengths 3 to 4 times greater than that of the original, press-fit polyethylene liner.