Palacos compared to Palamed bone cement in total hip replacement: a randomized controlled trial

Bone Cement in Adult Hip and Knee Reconstruction: A Review of Commercially Available Options and Clinical Outcomes

Polymethyl-methacrylate (PMMA) bone cement is used extensively in hip and knee arthroplasty. A thorough understanding of the basic chemistry underlying PMMA is important for orthopaedic surgeons because this underscores the specific way bone cement is used during surgery. Recently, clinical research has shed light on the various types of PMMA regarding the viscosity of the mixture and the effect of cement additives. These variations in composition may alter the clinical efficacy of implanted bone cement in hip and knee arthroplasty. Understanding these key differences will allow the surgeon to tailor the PMMA composition as needed to maximize outcomes of hip and knee arthroplasty. This review will summarize the preclinical feature of PMMA, evaluate current and past commercially available bone cement options, analyze preclinical results and clinical outcomes of various bone cement types, and highlight future areas of research.

Femoral Stem Cementation in Primary Total Hip Arthroplasty

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Femoral stem cementation has undergone considerable investigation since bone cement was first used in arthroplasty, leading to the evolution of modern femoral stem cementation techniques.

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Although there is a worldwide trend toward the use of cementless components, cemented femoral stems have shown superiority in some studies and have clear indications in specific populations.

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There is a large evidence base regarding cement properties, preparation, and application techniques that underlie current beliefs and practice, but considerable controversy still exists.

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Although the cementing process adds technical complexity to total hip arthroplasty, growing evidence supports its use in certain cohorts. As such, it is critical that orthopaedic surgeons and investigators have a thorough understanding of the fundamentals and evidence underlying modern cementation techniques.

Layered Double Hydroxide Modified Bone Cement Promoting Osseointegration via Multiple Osteogenic Signal Pathways

Poly(methyl methacrylate) (PMMA) bone cement has been widely used in orthopedic surgeries including total hip/knee replacement, vertebral compression fracture treatment, and bone defect filling. However, aseptic loosening of the interface between PMMA bone cement and bone often leads to failure. Hence, the development of modified PMMA that facilitates the growth of bone into the modified PMMA bone cement is key to reducing the incidence of aseptic loosening. In this study, MgAl-layered double hydroxide (LDH) microsheets modified PMMA (PMMA&LDH) bone cement with superior osseointegration performance has been synthesized. The maximum polymerization reaction temperature of PMMA&LDH decreased by 7.0 and 11.8 °C, respectively, compared with that of PMMA and PMMA&COL-I (mineralized collagen I modified PMMA). The mechanical performance of PMMA&LDH decreased slightly in comparison with PMMA, which is beneficial to alleviate stress-shielding osteolysis, and indirectly promote osseointegration. The superior osteogenic ability of PMMA&LDH has been demonstrated in vivo, which boosts bone growth by 2.17- and 18.34-fold increments compared to the PMMA&COL-I and PMMA groups at 2 months, postoperatively. Moreover, transcriptome sequencing revealed four key osteogenic pathways: p38 MAPK, ERK/MAPK, FGF, and TGF-β, which were further confirmed by IPA, qPCR, and Western blot assays. Hence, LDH-modified PMMA bone cement is a promising biomaterial to enhance bone growth with potential applications in relevant orthopedic surgeries.

Current concepts and outcomes in cemented femoral stem design and cementation techniques: the argument for a new classification system

Cemented implant fixation design principles have evolved since the 1950s, and various femoral stem designs are currently in use to provide a stable construct between the implant-cement and cement-bone interfaces.Cemented stems have classically been classified into two broad categories: taper slip or force closed, and composite beams or shaped closed designs. While these simplifications are acceptable general categories, there are other important surgical details that need to be taken into consideration such as different broaching techniques, cementing techniques and mantle thickness.With the evolution of cemented implants, the introduction of newer implants which have hybrid properties, and the use of different broaching techniques, the classification of a very heterogenous group of implants into simple binary categories becomes increasingly difficult. A more comprehensive classification system would aid in comparison of results and better understanding of the implants' biomechanics.We review these differing stem designs, their respective cementing techniques and geometries. We then propose a simple four-part classification system and summarize the long-term outcomes and international registry data for each respective type of cemented prosthesis. Cite this article: EFORT Open Rev 2020;5:241-252. DOI: 10.1302/2058-5241.5.190034.

Equivalent hip stem fixation by Hi-Fatigue G and Palacos R + G bone cement: a randomized radiostereometric controlled trial of 52 patients with 2 years' follow-up

Background and purpose - Long-term fixation of cemented femoral stems relies on several factors including cement adhesion and fatigue. Hi-Fatigue is a newer third-generation bone cement with low-viscosity properties at room temperature, good mechanical strength, and stable bone-cement interface in a laboratory testing environment. Palacos bone cement has excellent 10-year survival and is considered gold standard. We compared stem subsidence after fixation with Hi-Fatigue and Palacos bone cements using radiostereometry. Patients and methods - In a patient-blinded randomized controlled trial, 52 patients (30 women) at mean age 76 years (71-87) with osteoarthrosis and no osteoporosis received Hi-Fatigue G or Palacos R + G cement fixation of collarless, polished, double-tapered stems (CPT). Tantalum beads were inserted in the periprosthetic bone. Supine stereoradiographs were obtained postoperatively, 3 months, 6 months, 1 year, and 2 years after surgery. Oxford Hip Score (OHS) and VAS pain were recorded preoperatively and 1 and 2 years after surgery. Cement working times and properties were registered. Results - At 2 years, mean stem subsidence of 1.12 mm (95% CI 0.96-1.29) for Hi-Fatigue and 1.19 mm (CI 1.03-1.34) for Palacos was similar. Likewise, stem version was comparable between cement groups. Mean OHS and VAS pain were similar between cement groups. Cement working times were similar between cement groups, but the mean curing time was longer for Hi-Fatigue (13.7 min) than for Palacos (11.6 min). Interpretation - We found similar and generally low migration of CPT femoral stems inserted with Hi-Fatigue and Palacos bone cement until 2 years' follow-up, which indicates a good long-term survival of polished taper femoral stems inserted with both cement types.

Promoting Osseointegration of Ti Implants through Micro/Nanoscaled Hierarchical Ti Phosphate/Ti Oxide Hybrid Coating

In this study, micro/nanoscaled hierarchical hybrid coatings containing titanium (Ti) phosphate and Ti oxide have been fabricated with the aim of promoting osseointegration of Ti-based implants. Three representative surface coatings, namely, micro/nanograss Ti (P-G-Ti), micro/nanoclump Ti, (P-C-Ti), and micro/nanorod Ti (P-R-Ti), have been produced. In-depth investigations into the coating surface morphology, topography, chemical composition, and the surface/cell interaction have been carried out using scanning electron microscopy, transmission electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction, contact-angle measurement, and protein adsorption assay. In addition, in vitro performance of the coating (cell proliferation, adhesion, and differentiation) has been evaluated using rat bone marrow stromal cells (BMSCs), and in vivo assessments have been carried out based on a rat tibia implantation model. All the hybrid coating modified implants demonstrated enhanced protein adsorption and BMSC viability, adhesion and differentiation, with P-G-Ti showing the best bioactivity among all samples. Subsequent i n vivo osseointegration tests confirmed that P-G-Ti has induced a much stronger interfacial bonding with the host tissue, indicated by the 2-fold increase in the ultimate shear strength and over 6-fold increase in the maximum push-out force compared to unmodified Ti implants. The state-of-the-art coating technology proposed for Ti-based implants in this study holds great potential in advancing medical devices for next-generation healthcare technology.

A 2-year RSA study of the Vanguard CR total knee system: A randomized controlled trial comparing patient-specific positioning guides with conventional technique

Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA in 1 registry, and the literature is ambiguous about the efficacy of patient-specific positioning guides (PSPGs). The objective of this study was to investigate the stability of the cemented Vanguard CR Total Knee using 2 different surgical techniques. Our hypothesis was that there is no difference in migration when implanting the Vanguard CR with either PSPGs or conventional technique. We hereby present a randomized controlled trial of 2-year follow-up with radiostereometric analysis (RSA). Patients and methods - 40 TKAs were performed between 2011 and 2013 with either PSPGs or the conventional technique and 22 of these were investigated with RSA. Results - The PSPG (8 knees) and the conventional (14 knees) groups had a mean maximum total point motion (MTPM) (95% CI) of 0.83 (0.48-1.18) vs. 0.70 (0.43-0.97) mm, 1.03 (0.60-1.43) vs. 0.86 (0.53-1.19), and 1.46 (1.07-1.85) vs. 0.80 (0.52-1.43) at 3, 12, and 24 months respectively (p = 0.1). 5 implants had either an MTPM >1.6 mm at 12 months and/or a migration of more than 0.2 mm between 1- and 2-year follow-ups. 2 of these also had a peripheral subsidence of more than 0.6 mm at 2 years. Interpretation - 5 implants (3 in the PSPG group) were found to be at risk of later aseptic loosening. The PSPG group continuously migrated between 12 and 24 months. The conventional group had an initial high migration between postoperative and 3 months, but seemed more stable after 1 year. Although the difference was not statistically significant, we think the migration in the PSPG group is of some concern.