Anatomic Navigation Using the Transverse Acetabular Ligament for Acetabular Component Positioning in Total Hip Arthroplasty Through the Direct Anterior Approach.

The transverse acetabular ligament (TAL) is a reliable native anatomic landmark that can be used to guide accurate acetabular implant positioning during total hip arthroplasty through the direct anterior approach. The accurate acetabular implant position is defined by the preoperative plan, which corresponds to the Lewinnek safe zone. This article describes the anatomy of the TAL , exposure of the TAL, and pearls and pitfalls for exposure of the acetabulum during total hip arthroplasty through the direct anterior approach. This article discusses how the TAL is used to guide acetabular implant positioning and describes pilot data from our single surgeon case series (n = 31).

Macrophages and mesenchymal stromal cells support survival and proliferation of multiple myeloma cells.

Multiple myeloma (MM) is characterized by almost exclusive tropism of malignant cells for the bone marrow (BM) milieu. The survival and proliferation of malignant plasma cells have been shown to rely on interactions with nonmalignant stromal cells, in particular mesenchymal stromal cells (MSCs), in the BM microenvironment. However, the BM microenvironment is composed of a diverse array of cell types. This study examined the role of macrophages, an abundant component of BM stroma, as a potential niche component that supports malignant plasma cells. We investigated the proliferation of MM tumour cell lines when cultured alone or together with MSCs, macrophages, or a combination of MSCs and macrophages, using the carboxyfluorescein succinimidyl ester assay. Consistently, we observed increased proliferation of MM cell lines in the presence of either MSCs or macrophages compared to cell line-only control. Furthermore, the combined co-culture of MSCs plus macrophages induced the greatest degree of proliferation of myeloma cells. In addition to increased proliferation, MSCs and macrophages decreased the rate of apoptosis of myeloma cells. Our in vitro studies provide evidence that highlights the role of macrophages as a key component of the BM microenvironment facilitating the growth of malignant plasma cells in MM.