Mid-term clinical outcomes of the uncemented Robert Mathys pressfit cup

BACKGROUND The use of uncemented cups during total hip arthroplasty(THA)has gained popularity in recent years.The Robert Mathys(RM)pressfit cup,an uncemented monoblock implant is expected to preserve bone density due to its composition and external surface,while reducing backside wear with its monoblock construction.These factors should lead to a high survival rate of the implant.AIM To evaluate the mid-term survival and functional outcome of the RM Pressfit cup in a large study population.METHODS Between 2011 and 2020,we included 1324 patients receiving a primary THA using the RM pressfit cup.Final clinical follow-up was performed at 2 years postoperatively with the Dutch arthroplasty register used to assess implant status thereafter.Revision for acetabular failure and reason for revision were reported to evaluate implant survival,while the hip disability and osteoarthritis outcome score(HOOS)scores were used to assess functional outcome.RESULTS The mean age at surgery was 64.9 years.The mean follow-up was 4.6 years.Of the 1324 THAs performed,13 needed cup revisions within 5 years after index THA:5 due to aseptic loosening,6 due to infection,2 due to dislocation and 2 due to other causes.This resulted in a 5-year cup survival of 98.8%(95%CI:98.1-99.5).Nine of the cup revisions occurred within the first year after index THA.HOOS scores increased significantly in all domains during the first year and levelled out during the second year.CONCLUSION In the present study,the RM pressfit cup demonstrated excellent clinical outcomes at mid-term follow-up;however,future studies are needed to assess the long-term outcomes of this acetabular implant.

Correlation analysis between the interface membrane and loose hip prosthesis

Objective To analyze the cause of prosthesis loosening by observing the interface membranes harvested during the hip restoration operation. Methods A total of 28 specimens of interface membrane around the loose prosthesis were harvested from 28 patients undergoing the restoration of total hip replacement. All the specimens underwent the observation of appearance, light microscopy and scanning electronic microscopy(SEM). Results All the gaps around the loose prosthesis were filled with interface membrane of different thickness. The color of the most interface membrane was madder red, and the other one third of membrane was black. The comparatively thicker membrane was similar to scar connective tissue while the thinner was similar to fiber membrane. A large number of wear debris, macrophages and foreign-body giant cells were found under light microscope. With SEM observation a large number of different diameter collagen fibra structures that looked like scar tissues were arranged disorderly in a great mass, foreign particles and bone debris of different size were distributed unevenly, and the fibroblast was distributed in the collagen fiber. Conclusion Wear debris is related to inflammatory cell response around the interface membrane of the loose prosthesis. The wear debris engulfed by macrophage stimulates the interface membrane to release bone resorption factors (such as TNF) which lead to osteolysis, and this is one of the most important causes of the prosthesis loosening.

CALCITONIN GENE-RELATED PEPTIDE INDUCES FIBRO-BLASTS FROM HIP PSEUDOCAPSULE TO PRODUCE CYTOKINES

Objective To investigate calcitonin gene-related peptide (CGRP) involvement in the process of aseptic loosening. Methods We isolated fibroblasts from periprosthetic pseudocapsular tissue at the time of revision hip arthroplasty performed due to aseptic loosening. Fibroblasts were incubated for 24 h in the presence of CGRP, and the levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the media were determined using enzyme-linked immunosorbent assay kit. Results We found that the levels of IL-1β, IL-6, and TNF-α increased in a time-and concentration-dependent manner. ConclusionThese inflammatory cytokines play an important role in the development of periprosthetic osteolysis and implant loosening. Our results suggest that CGRP may be involved in the pathogenesis of aseptic loosening.

Therapeutic intervention for wear debris-induced aseptic implant loosening

Wear debris-induced aseptic loosening is an inflammatory bone disorder,which compromises the long-term success of total joint replacement.Despite the extensive research and great progress in treating inflammation-induced osteolysis for inflammatory arthritis,no drug has been proven for treatment/prevention of aseptic implant loosening.Also,there is very limited research on developing effective drug delivery systems for this pathological condition.In this review,we will discuss different therapeutic interventions and various delivery systems that have been developed for aseptic implant loosening.To provide the prospective for the future research in this area,the biology of wear particles-induced osteolysis,animal models developed for aseptic implant loosening and the potential challenges the field is facing are also presented in the discussion.

Macrophage-derived exosomes modulate wear particle-induced osteolysis via miR-3470b targeting TAB3/NF-κB signaling

Aseptic prosthesis loosening(APL)is one of the most prevalent complications associated with arthroplasty.The main cause is the periprosthetic osteolysis induced by wear particles.However,the specific mechanisms of crosstalk between immune cells and osteoclasts/osteoblasts during osteolysis are unclear.In this study,we report the role and mechanism of macrophage-derived exosomes in wear particle-induced osteolysis.The results of exosomes up-taken experiments revealed that osteoblast and mature osteoclasts capture macrophage-derived exosomes(M-Exo).Next-generation sequencing and RT-qPCR on M-Exo revealed that exosomal microRNA miR-3470b was downregulated in wear particle-induced osteolysis.The results of analysis on Luciferase reporter assays/fluorescence in situ hybridization(FISH)/immunofluorescence(IF)/immunohistochemistry(IHC)and co-culture experiments demonstrated that wear particles induced osteoclast differentiation by increasing the expression of NFatc1 via M-Exo miR-3470b targeting TAB3/NF-κB signaling.We also illustrate that engineered exosomes enriching miR-3470b facilitated to suppressed the osteolysis;the microenvironment enriching with miR-3470b could suppress wear particle-induced osteolysis via inhibition of TAB3/NF-κB in vivo.In summary,our findings indicate that macrophage-derived exosomes transfer to osteoclasts to induce osteolysis in wear particle-induced APL.Engineering exosomes enriching with miR-3470b might be a novel strategy for the targeting treatment of bone resorption-related diseases.

The effects of icariine concentration on osteoclasts bone resorption induced by titanium particles in vitro

In artificial joint replacement,osteoclast bone resorption induced by wear debris of the implant is a main reason for aseptic loosening.To extend the life of the prosthesis,detailed mechanisms of aseptic loosening and the ways to prevent it should be explored.The aim of this study was to investigate the in vitro effect of icariine on the bone resorption of osteoclasts induced by titanium particles.Macrophage colony stimulating factor(M-CSF)and receptor activator of NF-kB ligand(RANKL)were used to generate osteoclasts from RAW264.7 precursors.The proliferation of RAW264.7 precursors in the presence of different doses of icariine was evaluated by MTT assay.The cells were treated with titanium particles,titanium particles with icariine and culture medium only(control),respectively.At 48 h after treatment,the expression level of receptor activator of NF-kB(RANK)was detected by ELISA,and messenger RNA(mRNA)levels of tartrate-resistant acid phosphatase(TRAP),matrix metalloproteinase 9(MMP-9),carbonic anhydrase II(CAII)and Cathepsin K(CtsK)were determined by real-time polymerase chain reaction.Western blot was applied to analyze the expression levels of TRAP,RANK and CtsK.In addition,bone chips were cultured in the above conditions,and Toluidine blue staining was then employed to calculate the number and area of resorption pits in the bone chips.After treatment with icariine,expression level of RANK was significantly decreased in the RAW264.7 cell that induced by titanium particle and its cultural medium,mRNA and protein levels of TRAP,CAII,MMP-9 and CtsK were reduced as well.In addition,the numbers of bone resorption pits and areas on bone slices were both reduced by icariine challenging.Icariine could inhibit bone resorption of osteoclast induced by titanium particle,and it might be used as a promising drug for treating of aseptic loosening.

Magnetic suspension hip joint： an ideal design of an artificial joint

Background Artificial joints present certain problems such as osteal absorption and lysis induced by wear debris which leads to loosening of the prosthesis over a period of time. Here we propose a design of an artificial magnetic suspension joint that was prepared by integrating the medical theories of modern material science, magnetism, and medical physics.Methods According to clinical characteristic of biological and mechanical for hip joint, we designed the appearance and dimensions of magnetic suspension joint and placed neodymium-iron-boron permanent magnets in the prosthesis.As the same time, we performed mechanical and biological experiments using artificial magnetic suspension hip joints models.Results By simulated the human hip structure and the external load, we discovered the artificial magnetic suspension hip joints models had much lesser amount and size of wear debris than the ceramic/ceramic artificial hip joint prosthesis in friction wear tests. The force between the artificial joints with magnetic materials that we have calculated is feasible for application of artificial joint. The design of artificial magnetic suspension hip joints models was plausible technically and safe biologically.Conclusion Artificial magnetic suspension hip joints may effectively reduce the incidence of the loosening of prosthesis over a period of time.