Although prosthetic hip dislocation is a common reason for revision arthroplasty, few studies have comprehensively evaluated the radiographic factors that may lead to the need for revision. Therefore, the authors radiographically evaluated all prosthetic hip dislocations that were treated at one institution. They then specifically assessed those that required revision surgery. The authors found that the prosthetic center of rotation (pCOR) was located superolateral and inferolateral to the native COR (nCOR) in all patients. Most hips had pCOR distances more than 5 mm from the nCOR. Furthermore, most patients had cup inclination and anteversion angles within Lewinnek's previously defined "safe zone." Determining these similarities and properly planning these procedures may help decrease the instability rate and therefore improve the overall success of this procedure. [Orthopedics.2016; 39(5):e1011-e1018.].
Blood loss is a serious concern during lower extremity total joint arthroplasty with the estimated reduction in hemoglobin concentration known to vary between 2 and 4 g/dL after total knee arthroplasty (TKA). Allogeneic transfusions are commonly used to treat the acute blood loss and postoperative anemia to diminish the potential cardiovascular risks in up to 50% of such cases with a high volume of blood loss. However, these transfusions are associated with the risks of immunologic reactions, immunosuppression, and infection transmission. Multiple blood-saving strategies have been developed to minimize blood loss, to reduce transfusion rates, to decrease complications, and to improve outcomes in the postoperative period. Currently, there are no clear guidelines on the blood management strategies adopted to lessen the blood loss associated with TKA. The aim of this study was to review the literature and provide a broad summary of the efficacy and complications associated with several blood-saving measures that are currently used in the postoperative period. Evidence suggests that simple techniques such as limb elevation, cryotherapy, compression dressings, and drain clamping may reduce external drainage, however, whether these techniques lead to less allogeneic transfusions is currently debatable. Further research on using a combination of these strategies and their cost-effectiveness are needed.
The modern generations of cementless hip arthroplasty implant designs are based on precise fit and fill of components within the native bony geometry of the proximal femur and the acetabulum for enhanced implant longevity. Variations exist based on a number of population demographics such as age, gender, body mass index, and ethnicity. Recently, establishment of comprehensive electronic computerized tomographic databases from a diverse population worldwide have been key innovations in the field of implant development. This technology provides a potential improvement compared to historical techniques of implant design and manufacturing which involved limited trials on cadavers. Segmentation of the computerized data to generate three-dimensional models allows precise and accurate measurements of anatomical structures and may provide better understanding of anthropometric variations that occur among individuals. Evidence-and population-based computational analyses may provide a better tool for designing orthopaedic implants that deliver an enhanced fit for a more diverse patient population. Moreover, these population-based databases can also verify new designs by means of virtual implantation and analysis on specific or large groups of bones within the database. The aim of this paper is to describe a three dimensional modeling and analytical technology and to review the various applications of this technology in relation to hip arthroplasty.
The incidence of lower extremity total joint arthroplasty has increased tremendously during the past decade. In addition, there has been a change in the demographics of patients who undergo total knee arthroplasty (TKA). Nearly 41% of all TKAs (1.5 million procedures) in the United States were performed in patients who were 50 to 69 years of age.[1] With the current trends of cost reductions in the healthcare sector, there has been an increasing need for the development of newer cost-effective technologies in total joint arthroplasty with the ultimate potential goal of improving limb alignment, enhancing functional outcomes, providing more durable implant fixation, and superior overall implant survivorship. This initially led to the development of computer-assisted navigation, and more recently, in the use of patient-specific instrumentation in TKA. Moreover, the ensuing decade has also seen great progress in the technological front in TKA with the development of modern fabrication technologies such as additive layer manufacturing that are purportedly more commercially viable and have the potential to make a profound impact on the manufacturing of anatomically more conforming and complex implant geometries at faster rates and lower costs.[2] [3] [4] In this special supplement on the "Advances in Total Knee Arthroplasty" we will review some of these modern technologies.
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