Antibacterial and anti-inflammatory ultrahigh molecular weight polyethylene/tea polyphenol blends for artificial joint applications.

Periprosthetic joint infection (PJI) is one of the main causes for the failure of joint arthroplasty. In view of the limited clinical effect of oral/injectable antibiotics and the drug resistance problem, there is a pressing need to develop antibacterial implants with therapeutic antimicrobial properties. In this work, we prepared a highly antibacterial ultrahigh molecular weight polyethylene (UHMWPE) implant by incorporating tea polyphenols. The presence of tea polyphenols not only improved the oxidation stability of irradiated UHMWPE, but also gave it the desirable antibacterial property. The potent antibacterial activity was attributed to the tea polyphenols that produced excess intracellular reactive oxygen species and destroyed the bacterial membrane structure. The tea polyphenol-blended UHMWPE had no biological toxicity to human adipose-derived stem cells and effectively reduced bacteria-induced inflammation in vivo. These results indicate that tea polyphenol-blended UHMWPE is promising for joint replacement prostheses with multifunctionality to meet patient satisfaction.

Controversial Topics in Total Knee Arthroplasty: A 5-Year Update (Part 1).

BACKGROUND: This review article examines updates to the literature during the past 5 years on numerous topics related to total knee arthroplasty which were felt to have ongoing controversy. These include the use of peripheral nerve blocks and local infiltrative analgesia, intrathecal morphine, patellar resurfacing, and bearing designs. METHODS: For each individual topic, a literature search was conducted on several databases with emphasis on studies that were published in the past 5 years. Preference was given to meta-analyses and randomized controlled trials. RESULTS: Multimodal periarticular injections may provide an equally effective analgesic effect to peripheral nerve blocks, but are also muscle sparing and less invasive. The use of intrathecal morphine in addition to periarticular injections is less desirable given the potential side effects, associated cost, and lack of clear benefit intrathecal morphine beyond the 6- to 12-hour postoperative period. Patellar resurfacing was associated with a lower rate of revision surgery, similar or potentially improved satisfaction and functional outcomes, and no increased risk of complications compared with nonresurfacing. There are no clear or notable differences between cruciate-retaining and posterior-stabilized total knee designs in terms of clinical outcomes and survivorship. Medial pivot designs theoretically recreate more normal knee kinematics compared with cruciate-retaining or posterior-stabilized designs, although superiority has not yet been clearly demonstrated and additional long-term data is necessary, particularly for survivorship. CONCLUSIONS: By analyzing the results of the aforementioned studies, surgeons can implement the most up-to-date evidence-based care when doing total knee arthroplasty surgery. However, many of these selected topics continue to have a component of ongoing controversy with no definitive conclusions developed in recent literature.

Influence of Irradiation Temperature on Oxidative and Network Properties of X-Ray Cross-Linked Vitamin E Stabilized UHMWPE for Hip Arthroplasty.

Previous studies have shown that increased cross-link density, reduced free radicals, and increased antioxidant grafting resulting from electron-beam irradiation at elevated temperatures improved the wear performance and the oxidative stability of vitamin E blended UHMWPE. The current study explores the impact of elevated irradiation temperature on vitamin E blended UHMWPE using X-ray. We hypothesize that the effects of temperature would be similar to those observed after electron-beam irradiation due to the relatively high dose rate of X-rays. Two X-ray doses of 80 and 100 kGy and two irradiation temperatures, that is, room temperature and 100°C were considered. The reference was Vitelene®, a vitamin E stabilized polyethylene cross-linked with 80 kGy by e-beam at 100°C. Oxidation index and oxidation induction time, as well as cross-link density, gel fraction, and trans-vinylene index, were determined, as the oxidative and network properties are decisive for the long-term implant performance. Gel fraction and oxidation induction time were significantly improved subsequently to warm irradiation in comparison with the material irradiated at room temperature. In conclusion, X-ray irradiation at elevated temperatures resulted in an increase of cross-linking and oxidative resistance of vitamin E stabilized polyethylene comparable to those of e-beam irradiated UHMWPE.

High Oxidation Stability of Tea Polyphenol-stabilized Highly Crosslinked UHMWPE Under an in Vitro Aggressive Oxidative Condition.

BACKGROUND: Synovial fluid components, especially lipids, can trigger oxidation of ultrahigh-molecular-weight polyethylene (UHMWPE) artificial joint components in vivo. The use of antioxidants such as vitamin E effectively diminishes the oxidative cascade by capturing free radicals and reducing the oxidation potential of UHMWPE implants. Using a thermo-oxidative aging method, we recently found that tea polyphenols can enhance the oxidation resistance of irradiated UHMWPE in comparison with commercial vitamin E. However, it is yet unknown whether tea polyphenols can reduce lipid-induced oxidation. QUESTIONS/PURPOSES: We explored whether tea polyphenol-stabilized UHMWPE would exhibit (1) lower squalene absorption; (2) stronger oxidation resistance; and (3) lower content of free radicals than vitamin E-stabilized UHMWPE under a physiologically-motivated in vitro accelerated-aging model. METHODS: Tea polyphenol (lipid-soluble epigallocatechin gallate [lsEGCG]) and vitamin E were blended with UHMWPE powders followed by compression molding and electron beam irradiation at 100 and 150 kGy. Small cubes (n = 3, 60 mg, 4 × 4 × 4 mm) cut from the blocks were doped in squalene at 60°, 80°, 100°, and 120° C for 2 hours. Gravimetric change of the cubes after squalene immersion was measured to assess absorption. Thin films (n = 3, ∼60 µm) were also microtomed from the blocks and were doped at 120° C for 24 hours. Oxidation induction time (n = 3, 5 mg of material from the cubes) and incipient oxidation temperature (n = 3, thin films) were obtained to determine the oxidation stability. Signal intensity of the free radicals, obtained by electron spin resonance spectroscopy, was used to qualitatively rank the antioxidant ability of vitamin E and lsEGCG. RESULTS: Squalene absorption was comparable between lsEGCG/UHMWPE and vitamin E/UHMWPE at a given temperature and radiation dose. The oxidation induction time of 100 kGy-irradiated UHMWPE was increased with lsEGCG compared with vitamin E except at 120° C. For example, the oxidation induction time value of 100 kGy-irradiated lsEGCG/UHMWPE immersed at 60 C was 25.3 minutes (24.2-27.8 minutes), which was 8.3 minutes longer than that of 100 kGy-irradiated vitamin E/UHMWPE which was 17.0 minutes (15.0-17.1 minutes) (p = 0.040). After squalene immersion at 120° C, the incipient oxidation temperature of 100 and 150 kGy irradiated lsEGCG/UHMWPE was 234° C (227-240° C) and 227° C (225-229° C), which was higher than vitamin E-stabilized counterparts with value of 217° C (214-229° C; p = 0.095) and 216° C (207-218° C; p = 0.040), respectively. The electron spin resonance signal of 150 kGy irradiated lsEGCG/UHMWPE was qualitatively weaker than that of 150 kGy irradiated vitamin E/UHMWPE. CONCLUSIONS: lsEGCG-stabilized UHMWPE demonstrated higher oxidation resistance than vitamin E-stabilized UHMWPE after squalene immersion, likely because lsEGCG donates more protons to eliminate macroradicals than vitamin E. CLINICAL RELEVANCE: Our in vitro findings provide support that lsEGCG may be effective in protecting against oxidation that may be associated with synovial fluid-associated oxidation of highly crosslinked UHMWPE joint replacement components.

Addition of ceftaroline fosamil or vancomycin to PMMA: An in vitro comparison of biomechanical properties and anti-MRSA efficacy.

BACKGROUND: Ceftaroline is a cephalosporin that is effective against methicillin-resistant Staphylococcus aureus (MRSA) infections. The objective of this study was to determine the feasibility of using ceftaroline-loaded Polymethyl methacrylate (PMMA) as antibiotic cement against MRSA versus vancomycin-loaded PMMA in an in vitro setting. METHODS: PMMA pellets were prepared with three separate concentrations of each of the two antibiotics tested. They were tested to determine the effect of increasing concentration of antibiotics on the biomechanical properties of PMMA and antibiotic activity by measuring the zone of inhibition and broth elution assay. RESULTS: Ceftaroline PMMA at 3 wt%, three-point bending was 37.17 ± 0.51 N ( p < 0.001) and axial loading was 41.95 N ± 0.51 ( p < 0.001). At 5-wt% vancomycin-PMMA, three-point bending was 41.65 ± 0.79 N ( p = 0.02) and axial loading was 49.49 ± 2.21 N ( p = 0.01). Stiffness of ceftroline-loaded PMMA in low and medium concentration was significantly higher than the vancomycin. The zone of inhibition for ceftaroline was higher than vancomycin. Ceftaroline at 3 wt% eluted up to 6 weeks (0.3 ± 0.1 µg/ml) above the minimum inhibitory concentration (MIC) and vancomycin at 2.5 wt% eluted up to 3 weeks, same as MIC, that is, 0.5 ± 0.0 µg/ml. CONCLUSIONS: Ceftaroline, loaded at similar concentrations as vancomycin into PMMA, is a more potent alternative based on its more favourable bioactivity and elution properties, while having a lesser effect on the mechanical properties of the cement. The use of 3-wt% ceftaroline as antibiotic laden PMMA against MRSA is recommended. It should be noted that this was an in vitro study and to determine the clinical efficacy would need prospective, controlled and randomized studies.

An Alumina Ceramic Total Talar Prosthesis for Avascular Necrosis of the Talus.

Avascular necrosis tends to occur in the talus because of poor blood supply caused by the extended coverage to the articular cartilage on its surface. Treatment is conservative in the earlier stage of this disease; however, surgical treatment is usually indicated in the advanced stage. Nonunion, leg length discrepancy, or hindfoot instability may occur in patients treated with ankle or tibio-talo-calcaneal fusion. Arthroplasty using a customized total talar prosthesis designed using the computed tomography image of contralateral talus has the potential advantages of weightbearing in the earlier postoperative phase, prevention of lower extremity discrepancy, and maintenance of joint function.

Does low hydroxyl group surface density explain less bacterial adhesion on porous alumina?

BACKGROUND: Bacterial adhesion depends on surface materials. Recently it was suggested that ceramic-on-ceramic bearings could be less prone to infection than other bearings. We examined the possibility that porous alumina ceramic could be less susceptible to bacterial adhesion. HYPOTHESIS: As hydroxyl groups (OH) on material surface are a major factor governing the surface properties (for example: adsorption, first non-specific step of bacterial adhesion), we hypothesized that alumina had lower OH group density than other material. Thus, we asked (i) if bacterial adhesion was lower on alumina than on titanium alloy, stainless steel and polyethylene and (ii) if OH group density was also lower on alumina. MATERIAL AND METHODS: We performed (i) in vitro bacterial cultures on porous alumina, titanium, stainless steel and polyethylene using Staphylococcus aureus and Pseudomonas aeruginosa, known to adhere to surfaces. Bacterial cultures were done 3 times in duplicate for each material and each strain. Colony Forming Units (CFU) per cm2 were measured; (ii) Neutral red reagent helped obtaining OH density estimates using spacer arms. UV-visible spectrophotometry method with Neutral red test, reproduced twice for each surface, provided µg/cm2 measurements of OH density. RESULTS: There was significantly less P. aeruginosa adherent on porous alumina (2.25×104 CFU/cm2) than on titanium (4.27×105 CFU/cm2, p=0.01), on stainless steel (2.44×105 CFU/cm2, p=0.02) and on polyethylene (7.29×105 CFU/cm2, p<0.001). S. aureus was significantly less adherent on porous alumina (3.22×105 CFU/cm2) than on polyethylene (5.23×106 CFU/cm2, p=0.01), but there was no difference with titanium (1.64×106 CFU/cm2, p=0.08) and stainless steel (1.79×106 CFU/cm2, p=0.1). There was significantly lower Neutral red grafted on porous alumina (0.09µg/cm2) than on titanium (8.88µg/cm2, p<0.0001), on stainless steel (39.8µg/cm2, p=0.002) and on polyethylene (4.5µg/cm2, p<0.01). However, no correlation was found between bacterial adherence and OH group density. DISCUSSION: Bacterial adherence on porous alumina was lower than on other bearings. Although there were less surface OH groups on porous alumina, we failed establishing a statistical correlation between bacterial adherence and OH group density. LEVEL OF EVIDENCE: IV, in vitro study.

Clinical and Radiological Outcomes of Transfibular Total Ankle Arthroplasty.

BACKGROUND:: Ankle arthritis is a highly limiting pathology that causes pain and functional limitation with subsequent deterioration of quality of life. With recent advances in surgical instrumentation and techniques, prosthetic replacement of the ankle has proven to be a valid alternative to arthrodesis with comparable outcomes. The purpose of this study was to evaluate clinical and radiological findings in a transfibular total ankle replacement with follow-up of at least 2 years. METHODS:: This prospective study included 89 patients who underwent transfibular total ankle arthroplasty from May 2013 to February 2016. The mean age was 53.2 ± 13.5 years. All patients were followed for at least 24 months postoperatively with an average follow-up of 42.0 ± 23.5 months. Patients were assessed clinically and radiographically preoperatively and at 6, 12, and 24 months postoperatively. RESULTS:: At 24 months postoperatively, patients demonstrated statistically significant improvement in the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle Hindfoot Score from 33.8 ± 14.3 to 88.5 ± 6.6 ( P < .001), visual analog scale (VAS) from 80.5 ± 17.0 to 14.1 ± 9.2 ( P < .001), and Short Form-12 Physical and Mental Composite Scores from 29.9 ± 6.7 and 43.3 ± 8.6 to 47.0 ± 7.6 and 53.3 ± 8.1, respectively ( P < .001). In addition, ankle dorsiflexion and plantarflexion improved from 6.2 ± 5.5 and 9.6 ± 5.8 degrees to 24.2 ± 7.9 and 18.1 ± 7.6 degrees, respectively ( P < .001). Radiographically, patients demonstrated maintained neutral alignment of the ankle at 24 months. No patient demonstrated any radiographic evidence of tibial or talar lucency at final follow-up. Seven patients underwent reoperation for removal of symptomatic hardware (6 fibular plates, 1 syndesmotic screw); 2 patients experienced delayed wound healing. The first one was treated with plate removal and flap coverage. The second one required fibular plate removal. One patient developed a postoperative prosthetic infection requiring operative debridement, removal of implants, and placement of an antibiotic spacer. CONCLUSION:: This study found that transfibular total ankle replacement was a safe and effective option for patients with ankle arthritis resulting in improvements in patient-reported outcomes, range of motion, and radiographic parameters. However, further studies are required to determine the mid- and long-term performance of these implants. LEVEL OF EVIDENCE:: Level IV, case series.

Procedure for single-stage implant retention for chronic periprosthetic infection using topical degradable calcium-based antibiotics.

INTRODUCTION: Surgical treatment using DAIR (debridement, systemic antibiotics, and implant retention) can lead to high rates of treatment success in cases of early periprosthetic joint infection (PJI) but can fail in late-onset cases. Supplementary local antibiotic therapy is not yet generally established and lacks evidence-based proof of efficacy. The aim of this study was to analyze DAIR outcomes in recurrent PJI cases and patients who are not suitable for a two-stage exchange, using additional degradable calcium-based antibiotics. METHODS: All patients fulfilled the Infectious Diseases Society of America (IDSA) guidelines for chronic late-onset PJI but were not suitable for a multistage procedure because of their individual operation risk. A total of 42 patients (mean age, 73 years) were treated using a single-stage algorithm consisting of DAIR, followed by implantation of degradable antibiotics chosen in accordance with an antibiogram. OSTEOSET® (admixed ceftriaxone/vancomycin/tobramycin) and Herafill-Gentamycin® were used as carrier systems. The follow-up period was 23 months (± SD, 10.3). The study is based on institutional review board (IRB) approval. RESULTS: The clinical entities were chronic PJI of the hip (45.2%), knee (28.6%), and knee arthrodesis (26.2%). The bacterial spectrum was composed of Staphylococcus epidermidis (29%), Staphylococcus aureus (21%), and Enterococcus faecalis (21%). 21.4% showed a combination of two or more bacteria. In 73.8%, permanent remission was achieved, while 11.9% showed chronic PJI under implant retention. Implant retention could be achieved in 85.7%. CONCLUSION: DAIR usually shows low levels of success in difficult-to-treat cases. However, we could demonstrate the successful treatment of patients with recurrent PJI (typically considered DAIR-inappropriate) using degradable antibiogram-based topical calcium-based antibiotics. Over 70% of the cases went to remission and over 85% of the implants could be retained.

Enhanced oxidation stability of highly cross-linked ultrahigh molecular weight polyethylene by tea polyphenols for total joint implants.

Despite being currently state-of-the-art to prevent the oxidation of irradiated ultrahigh molecular weight polyethylene (UHMWPE) bearings, vitamin E (VE) poses concerns in the loss of cross-linking efficiency and is limited to be used at very low concentrations. It thus emphasizes the urgent demand for more efficient stabilizers. In this study, oxidation stability of highly cross-linked UHMWPE was demonstrated to be enhanced by tea polyphenols, such as lipid-soluble tea polyphenols (lsPPT), epigallocatechin gallate (EGCG), and lipid-soluble epigallocatechin gallate (lsEGCG). These antioxidants were blended with UHMWPE granules and consolidated by compression molding prior to E-beam irradiation. The presence of tea polyphenols substantially prolonged oxidation induction time of the irradiated UHMWPE before and after accelerated aging. Especially, lsEGCG was significantly superior to VE in terms of stabilizing capacity. Explained by the hydrogen donation mechanism, tea polyphenols with multiple phenolic hydroxyls could scavenge more radiation-induced free radicals than VE with only one phenolic hydroxyl, which was verified by the electron spin resonance spectra. Intriguingly, tea polyphenols showed less inhibitive effect on the cross-link density of irradiated UHMWPE than VE. Besides, there is no significant difference in crystallinity, mechanical performance as well as in vitro biocompatibility between the irradiated UHMWPE stabilized by tea polyphenols and VE. These findings highlight tea polyphenols, especially lsEGCG, are promising alternatives to extend the life span of UHMWPE implants.

Efficacy of antibiotic treatment of implant-associated Staphylococcus aureus infections with moxifloxacin, flucloxacillin, rifampin, and combination therapy: an animal study.

The efficacy of antibiotic monotherapy and combination therapy in the treatment of implant-associated infection by Staphylococcus aureus was evaluated in an animal study. The femoral medullary cavity of 66 male Wistar rats was contaminated with S. aureus (ATCC 29213) and a metal device was implanted, of which 61 could be evaluated. Six treatment groups were studied: flucloxacillin, flucloxacillin in combination with rifampin, moxifloxacin, moxifloxacin in combination with rifampin, rifampin, and a control group with aqua. The treatment was applied for 14 days. After euthanasia, the bacterial counts in the periprosthetic bone, the soft tissue, and the implant-associated biofilm were measured. Both antibiotic combination treatments (moxifloxacin plus rifampin and flucloxacillin plus rifampin) achieved a highly significant decrease in microbial counts in the bone and soft tissue and in the biofilm. Mono-antibiotic treatments with either moxifloxacin or flucloxacillin were unable to achieve a significant decrease in microbial counts in bone and soft tissue or the biofilm, whilst rifampin was able to reduce the counts significantly only in the biofilm. Antibiotic resistance was measured in 1/3 of the cases in the rifampin group, whereas no resistance was measured in all other groups. The results show that combinations of both moxifloxacin and flucloxacillin plus rifampin are adequate for the treatment of periprosthetic infections due to infections with S. aureus, whereas monotherapies are not effective or not applicable due to the rapid development of antibiotic resistance. Therefore, moxifloxacin is an effective alternative in combination with rifampin for the treatment of implant-associated infections.

Total Wrist Arthroplasty.

Total wrist arthroplasty (TWA), first performed in the late 19th Century, is still an infrequently used operation. It is most commonly indicated in patients with rheumatoid arthritis who have pan-carpal wrist involvement. It is an alternative to total wrist arthrodesis in patients who wish to preserve joint motion. Patients must lead a low-demand lifestyle and have failed non-operative measures. Complications are not insignificant and have been reported to be as high as 43%. Modern generation implants most often fail due to dislocation or loosening. Because wrist arthrodesis remains the gold standard treatment, particularly in patients with higher physical demands, it remains to be seen whether TWA will gain greater acceptance as prosthetic designs evolve.

Combining 3D human in vitro methods for a 3Rs evaluation of novel titanium surfaces in orthopaedic applications.

In this study, we report on a group of complementary human osteoblast in vitro test methods for the preclinical evaluation of 3D porous titanium surfaces. The surfaces were prepared by additive manufacturing (electron beam melting [EBM]) and plasma spraying, allowing the creation of complex lattice surface geometries. Physical properties of the surfaces were characterized by SEM and profilometry and 3D in vitro cell culture using human osteoblasts. Primary human osteoblast cells were found to elicit greater differences between titanium sample surfaces than an MG63 osteoblast-like cell line, particularly in terms of cell survival. Surface morphology was associated with higher osteoblast metabolic activity and mineralization on rougher titanium plasma spray coated surfaces than smoother surfaces. Differences in osteoblast survival and metabolic activity on titanium lattice structures were also found, despite analogous surface morphology at the cellular level. 3D confocal microscopy identified osteoblast organization within complex titanium surface geometries, adhesion, spreading, and alignment to the biomaterial strut geometries. Mineralized nodule formation throughout the lattice structures was also observed, and indicative of early markers of bone in-growth on such materials. Testing methods such as those presented are not traditionally considered by medical device manufacturers, but we suggest have value as an increasingly vital tool in efficiently translating pre-clinical studies, especially in balance with current regulatory practice, commercial demands, the 3Rs, and the relative merits of in vitro and in vivo studies. Biotechnol. Bioeng. 2016;113: 1586-1599. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.

Local delivery of mutant CCL2 protein-reduced orthopaedic implant wear particle-induced osteolysis and inflammation in vivo.

Total joint replacement (TJR) has been widely used as a standard treatment for late-stage arthritis. One challenge for long-term efficacy of TJR is the generation of ultra-high molecular weight polyethylene wear particles from the implant surface that activates an inflammatory cascade which may lead to bone loss, prosthetic loosening and eventual failure of the procedure. Here, we investigate the efficacy of local administration of mutant CCL2 proteins, such as 7ND, on reducing wear particle-induced inflammation and osteolysis in vivo using a mouse calvarial model. Mice were treated with local injection of 7ND or phosphate buffered saline (PBS) every other day for up to 14 days. Wear particle-induced osteolysis and the effects of 7ND treatment were evaluated using micro-CT, histology, and immunofluorescence staining. Compared with the PBS control, 7ND treatment significantly decreased wear particle-induced osteolysis, which led to a higher bone volume fraction and bone mineral density. Furthermore, immunofluorescence staining showed 7ND treatment decreased the number of recruited inflammatory cells and osteoclasts. Together, our results support the feasibility of local delivery of 7ND for mitigating wear particle-induced inflammation and osteolysis, which may offer a promising strategy for extending the life time of TJRs.

Wear studies on plasma-sprayed Al2O3 and 8mole% of Yttrium-stabilized ZrO2 composite coating on biomedical Ti-6Al-4V alloy for orthopedic joint application.

This paper presents the wear characteristics of the composite ceramic coating made with Al2O3-40wt%8YSZ on the biomedical grade Ti-6Al-4V alloy (grade 5) used for total joint prosthetic components, with the aim of improving their tribological behavior. The coatings were deposited using a plasma spraying technique, and optimization of plasma parameters was performed using response surface methodology to obtain dense coating. The tribological behaviors of the coated and uncoated substrates were evaluated using a ball-on-plate sliding wear tester at 37°C in simulated body-fluid conditions. The microstructure of both the titanium alloy and coated specimen were examined using an optical microscope and scanning electron microscope. The hardness of the plasma-sprayed alumina-zirconia composite coatings was 2.5 times higher than that of the Ti-6Al-4V alloy, while the wear rate of Ti-6Al-4V alloy was 253 times higher than that of the composite-coated Ti-6Al-4V alloy. The superior wear resistance of the alumina-zirconia coated alloy is attributed to its enhanced hardness and intersplat bonding strength. Wear-track examination showed that the predominant wear mechanism of Ti-6Al-4V alloy was abrasive and adhesive wear, whereas, in the case of alumina-zirconia composite coated alloy, the wear was dominated by microchipping and microcracking.

An Alumina Ceramic Total Talar Prosthesis for Osteonecrosis of the Talus.

BACKGROUND: Treatment of osteonecrosis of the talus is challenging. Total talar replacement has the potential to restore the function of the ankle joint without an associated leg-length discrepancy. The purpose of the present study was to investigate postoperative function and pain after total talar replacement in patients with osteonecrosis of the talus. METHODS: Fifty-five ankles in fifty-one consecutive patients with osteonecrosis of the talus who were treated with a total talar replacement from 2005 to 2012 were included in the investigation. Scores according to the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale and the Ankle Osteoarthritis Scale (AOS) were assessed before surgery and at the final follow-up evaluation. RESULTS: According to the JSSF ankle-hindfoot scale, the score for pain improved from a mean (and standard deviation) of 15 ± 9.4 points (range, 0 to 20 points) to 34 ± 5.6 points (range, 20 to 40 points); the score for function, from 21.2 ± 9.7 points (range, 4 to 38 points) to 45.1 ± 4.0 points (range, 37 to 50 points); the score for alignment, from 6.0 ± 2.8 points (range, 5 to 10 points) to 9.8 ± 0.9 points (range, 5 to 10 points); and the total score, from 43.1 ± 17.0 points (range, 11 to 68 points) to 89.4 ± 8.4 points (range, 76 to 100 points). According to the AOS scale, the score for "pain at its worst" improved from a mean of 6.1 ± 3.3 points (range, 0 to 9.9 points) to 2.0 ± 1.7 points (range, 0 to 6.3 points). CONCLUSIONS: Prosthetic talar replacement is a useful procedure for patients with osteonecrosis of the talus as it maintains ankle function.

Human plasma protein adsorption onto alumina nanoparticles relevant to orthopedic wear.

PURPOSE: Wear of ceramic orthopedic devices generates nanoparticles in vivo that may present a different biological character from the monolithic ceramic from which they are formed. The current work investigated protein adsorption from human plasma on alumina nanoparticles and monolithic samples representative of both wear particles and the ceramic components as implanted. MATERIALS AND METHODS: A physicochemical characterization of the particles and their dispersion state was carried out, and the protein adsorption profiles were analyzed using 1D SDS-PAGE and mass spectrometry. RESULTS: Significant differences in protein-binding profiles were identified where the nanoparticles selectively bound known transporter proteins rather than the more highly abundant serum proteins that were observed on the monoliths. CONCLUSIONS: Proteins associated with opsonization of particles were seen to be present in the protein corona of the nanoparticles, which raises questions regarding the role of wear particles in periprosthetic tissue inflammation and aseptic loosening.

Assessment of non-contacting optical methods to measure wear and surface roughness in ceramic total disc replacements.

This study presents a method for measuring the low volumetric wear expected in ceramic total disc replacements, which can be used to replace intervertebral discs in the spine, using non-contacting optical methods. Alumina-on-alumina ball-on-disc tests were conducted with test conditions approximating those of cervical (neck region of the spine) total disc replacement wear tests. The samples were then scanned using a three-dimensional non-contacting optical profilometer and the data used to measure surface roughness and develop a method for measuring the wear volume. The results showed that the magnification of the optical lens affected the accuracy of both the surface roughness and wear volume measurements. The method was able to successfully measure wear volumes of 0.0001 mm(3), which corresponds to a mass of 0.0001 mg, which would have been undetectable using the gravimetric method. A further advantage of this method is that with one scan the user can measure changes in surface topography, volumetric wear and the location of the wear on the implant surface. This method could also be applied to more severe wear, other types of orthopaedic implants and different materials.