Metal-on-Metal Total Hip Arthroplasty: Current Recommendations and Lessons Learned

Metal-on-metal (MoM) hip arthroplasty was re-popularized in the 1990s to resolve osteolysis and wear associated with metal-on-polyethylene products. Despite early success, registries began reporting high failure rates due to adverse reactions to metal debris (ARMD), manifesting as pseudotumors, hip effusions and osteolysis. Evaluation includes clinical exam, advanced imaging, and blood metal ions and infectious markers. This review provides physicians with an evidence-based update on the 1) clinical workup and management of patients with existing MoM implants, 2) risk and prognostic factors associated with suboptimal results and 3) the precipitating events and lessons learned applicable to future orthopedic prosthesis.

Investigation of Orthopedic Prosthesis Socket Management after Transfemoral Amputation by Expert Survey

Prosthesis treatment requires the close interaction of different actors. In fitting prostheses to patients, special attention is given to the manufacturing of the socket. The continuous development of the technologies involved in the fitting and optimization of prostheses is shown in the literature. The assessment of orthopedic technicians and their influence in the process is thus far largely unexplored. Ten orthopedic technicians were interviewed about the socket fitting process after transfemoral amputation. The research goal was to clarify the socket treatment process with regards to the German context. The results showed that the orthopedic technicians focussing on the patient during the fitting process. This study underlines the importance of interaction and empathy. Volume fluctuations are decisive within the treatment process and are interactively influenced by various factors. Furthermore, the research emphasizes the need for appropriate assistive technologies and the potential for the further development of existing systems.

Antibiotic Tolerance of Staphylococcus aureus Biofilm in Periprosthetic Joint Infections and Antibiofilm Strategies

The need for bone and joint prostheses is currently growing due to population aging, leading to an increase in prosthetic joint infection cases. Biofilms represent an adaptive and quite common bacterial response to several stress factors which confer an important protection to bacteria. Biofilm formation starts with bacterial adhesion on a surface, such as an orthopedic prosthesis, further reinforced by matrix synthesis. The biofilm formation and structure depend on the immediate environment of the bacteria. In the case of infection, the periprosthetic joint environment represents a particular interface between bacteria, host cells, and the implant, favoring biofilm initiation and maturation. Treating such an infection represents a huge challenge because of the biofilm-specific high tolerance to antibiotics and its ability to evade the immune system. It is crucial to understand these mechanisms in order to find new and adapted strategies to prevent and eradicate implant-associated infections. Therefore, adapted models mimicking the infectious site are of utmost importance to recreate a relevant environment in order to test potential antibiofilm molecules. In periprosthetic joint infections, Staphylococcus aureus is mainly involved because of its high adaptation to the human physiology. The current review deals with the mechanisms involved in the antibiotic resistance and tolerance of Staphylococcus aureus in the particular periprosthetic joint infection context, and exposes different strategies to manage these infections.

Practice Patterns for Postoperative Radiation Therapy in Patients with Metastases to the Long Bones: Survey of the Japanese Radiation Oncology Study Group

BackgroundBecause of the lack of evidence on practice patterns of postoperative radiation therapy (PORT)in patients with metastases to the long bones, it is essential to characterize the current practice patterns and identify factors affecting dose-fractionation to aid future clinical trials. MethodsThe palliative radiation therapy subgroup of the Japanese Radiation Oncology Study Group conducted an internet-based survey to determine the prescription practices and various dose-fractionations used for PORT. Additionally, responders were asked to recommend dose-fractionations in four hypothetical cancer cases, wherein each case represented a patient with impending pathological fractures and one of the four features: limited prognosis, solitary metastasis, radio-resistant primary tumor, or long-term survival. Responders were asked to indicate their preferred irradiation fields and the reasons for choosing long-course radiotherapy over short-course radiotherapy (RT). ResultsEighty-nine radiation oncologists from 67 institutions and 151 RT plans were included. Twenty-two different dose-fractionations were used; the most commonly used and recommended dose-fractionation was 30 Gy in 10 fractions. “Local control” was most the common reason for preferring longer course RT. While fractionated higher-dose regimens were preferred in case of oligometastasis, low dose regimens were preferred in case of limited prognosis; single fraction RT was never preferred. Most respondents recommended involvement of “the entire orthopedic prosthesis.” ConclusionFor PORT of metastases to the long bones, 30 Gy in 10 fractions for the entire orthopedic prosthesis is preferred in current practice. Oligometastasis and a limited prognosis influence the selection of high- and low-dose regimens, respectively. Single fraction RT is never preferred.

Investigation for the Effects of Newly Designed Hip Prosthesis on Crack Propagation Using Probabilistic Methodology

In orthopedic prosthesis design, finite element method is one of the commonly used mathematical methods for performing structural analyzes and reducing test costs before it is applied to the patient. Surgeons and engineers should work together to design reliable durable and hip replacement. Desirable functional requirements for prosthesis design include high fatigue life, small relative displacement between the prosthesis-cement interface, and reduced stress on the bone and prosthesis. For this purpose, the progression of the fracture was calculated by applying the scenario of the presence of crack in the bone cement of the designed prosthesis using optimization methodology. The same conditions were analyzed in commercially available Charnley type prosthesis and the results were compared. When the obtained results are examined, it is seen that the newly designed prosthesis is more effective than the Charnley type prosthesis.

Investigation of the Temperature-Related Wear Performance of Hard Nanostructured Coatings Deposited on a S600 High Speed Steel

Thin hard coatings are widely known as key elements in many industrial fields, from equipment for metal machining to dental implants and orthopedic prosthesis. When it comes to machining and cutting tools, thin hard coatings are crucial for decreasing the coefficient of friction (COF) and for protecting tools against oxidation. The aim of this work was to evaluate the tribological performance of two commercially available thin hard coatings deposited by physical vapor deposition (PVD) on a high speed tool steel (S600) under extreme working conditions. For this purpose, pin-on-disc wear tests were carried out either at room temperature (293 K) or at high temperature (873 K) against alumina (Al2O3) balls. Two thin hard nitrogen-rich coatings were considered: a multilayer AlTiCrN and a superlattice (nanolayered) CrN/NbN. The surface and microstructure characterization were performed by optical profilometry, field-emission gun scanning electron microscopy (FEGSEM), and energy dispersive spectroscopy (EDS).

Draft Genome Sequence of Staphylococcus epidermidis Clinical Strain GOI1153754-03-14 Isolated from an Infected Knee Prosthesis

ABSTRACT We announce the draft genome sequence of Staphylococcus epidermidis clinical strain GOI1153754-03-14, isolated from an infected orthopedic prosthesis. The reported genomic sequence will provide valuable information concerning the mechanisms of the biofilm formation on metallic implants.