Knee Implants Research Articles

Titanium niobium nitride knee implants are not inferior to chrome cobalt components for primary total knee arthroplasty at medium-term follow-up.

Oxidized zirconium (Oxinium), titanium nitride (TiN) or titanium niobium nitride (TiNbN) coated implants became in recent years available for an increasing amount of total knee arthroplasty (TKA) systems. The hypothesis of this study was that the use of TiNbN-coated components would not lead to inferior results compared to conventional implants and that none of the metal hypersensitivity patients receiving TiNbN-coated implants would require revision for metal allergy. This retrospective study compared 53 Titanium Niobium Nitride coated TKA with 103 conventional chrome cobalt implants of the same design. Patients were evaluated at a minimal follow-up of 3 years. No differences in clinical, radiological or patient-reported outcome measurements were observed between these groups. A survivorship of 96% without differences in revision rates was observed at medium-term follow-up of 6.5years. Metal allergy leading to contact or generalized dermatitis after TKA is very rare and usually linked to chrome or cobalt hypersensitivity. Nickel release from knee implants has not been shown to lead to cutaneous symptoms, but unexplained pain and swelling, peri-prosthetic osteolysis and component loosening remain potential issues not fully understood. The use of coated implants eliminates this factor from the diagnostic equation in case of postoperative dissatisfaction. The use of titanium niobium nitride coated implants for primary knee osteoarthritis in self-reported metal hypersensitivity patients shows similar outcomes and survivorship rates as conventional chrome cobalt TKA, with no revisions for allergy at medium-term follow-up.

Inconsistent Surgical Implant Documentation: A Case Study in Total Knee and Hip Arthroplasty

Value-based care initiatives require accurate quantification of resource utilization. This study explores hospital resource documentation performance for total knee and hip arthroplasty (TKA, THA) implants and how this may differ between hospitals. This retrospective study utilized the Premier discharge database, years 2006 to 2020. TKA/THA cases were categorized into 5 tiers based upon the completeness of implant component documentation: Platinum, Gold, Silver, Bronze, Poor. Correlation between TKA and THA documentation performance (per-hospital percentage of Platinum cases) was assessed. Logistic regression analyses measured the association between hospital characteristics (region, teaching status, bed size, urban/rural) and satisfactory documentation. TKA/THA implant documentation performance was compared to documentation for endovascular stent procedures. Individual hospitals tended to have very complete (Platinum) or very incomplete (Poor) documentation for both TKA and THA. TKA and THA documentation performance were correlated (correlation coefficient = .70). Teaching hospitals were less likely to have satisfactory documentation for both TKA (P = .002) and THA (P = .029). Documentation for endovascular stent procedures was superior compared to TKA/THA. Hospitals' TKA and THA-related implant documentation performance is generally either very proficient or very poor, in contrast with often well-documented endovascular stent procedures. Hospital characteristics, other than teaching status, do not appear to impact TKA/THA documentation completeness.

AN ADDITIVE MANUFACTURING AND LATTICE STRUCTURES PERSPECTIVE FOCUSED ON BIOMIMETIC KNEE IMPLANT DESIGN

There are different types of knee implants, each seeking to restore the natural behavior of a healthy knee. Factors such as contact stress, wear and fatigue have been extensively analyzed for their design.

Sub-optimal femoral fit in total knee arthroplasty, a systematic review of human femoral data vs off-the-shelf contemporary femoral components

PurposeThe purpose of the current study is to investigate the inadequacy of fit between the human distal femur and the knee implants offerings and describe the available strategies to overcome this issue.MethodsA systematic research of the literature was performed to identify studies reporting morphologic measures of the distal femur. Studies were excluded if they included unhealthy knees or the morphological analysis did not report the two key dimensions to identify the patient’s unique anatomy: AP length and mediolateral (ML) width. Clinically relevant component overhang or underhang was considered when the metal-bone mismatch was > 3 mm as described in the literature.ResultsSix studies with anthropometric analysis of 1395 distal femurs met the inclusion criteria. The analysis revealed that by employing the available sizes of four current “state-of-the-art” primary off-the shelf (OTS) femoral implants up to 13–41% would show underhang and 9–27% overhang clinically relevant and the introduction of narrower sizes did not reduce this percentage of underhang but improved the overhang rate of 10–15%.ConclusionsWhenever an ML/AP mismatch in encountered in the operating room, adaptations are needed, and these bring about deleterious biomechanical and clinical complications. Therefore, this study highlights the need for implants design with multiple ML offerings per AP size, since they provide not only more sizes options but more femoral shapes to match the different ML sizes of the distal femur, compared to designs with single ML offerings for a given femoral AP dimension.

Trends in characterization and analysis of TKA implants for 3D printing

In almost every country, knee joint problems are common among humans. As per American Academy of Orthopedic Surgeons, it is estimated that 3.5 million individuals in the world will undergo knee replacement surgery by 2030. People with advanced rheumatoid arthritis, or long-standing osteoarthritis are usually affected by this deformity due to changes in lifestyle. These conditions mainly affect middle-aged and elderly individuals with osteoarthritis or severe knee injuries. These problems can be overcome with the help of total knee implants by undergoing surgical procedures for providing relaxation & comfort to the knee joint. These procedures are also known as total knee arthroplasty (TKA). TKA is an ancient surgical process employed for treating intracapsular knee joint arthritis. It is promising technique greatly augmenting a patient’s standard of life. The main components of TKA are femoral and tibial components, spacer, and patellar components respectively. Materials often used in these components include titanium, Ti6Al4V, cobalt-chromium alloys, polyethylene and bio compatible materials. 3D printing of TKA implants is a recent avenue being explored by researchers in an attempt to develop a better replacement for the conventional implants for providing comfort to the patients. This paper presents thorough assessment of research trends in mechanical characterization and finite element analysis of knee joint prosthetics, especially TKA implants for 3D printing.

The BioPoly Partial Resurfacing Knee Implant Provides Beneficial Clinical Outcomes: A Concise Follow-up, at 5 Years, of a Previous Report.

We previously conducted a single-arm, prospective study in which 31 patients (mean age [and standard deviation], 42.5 ± 11.3 years) with cartilage lesions were treated with use of the BioPoly Partial Resurfacing Knee Implant. Treatment outcomes were compared with those reported for the standard of care, microfracture. We found that the mean KOOS (Knee injury and Osteoarthritis Outcome Score) Quality of Life score at 5 years in the BioPoly cohort was noninferior to (p = 0.004), and indeed greater than (p = 0.021), that in the microfracture cohort. The BioPoly cohort demonstrated improvement in the mean scores for all KOOS domains at every postoperative time point (p < 0.025). The mean score for the visual analog scale (VAS) for pain significantly improved (p < 0.025) at all time points up to 4 years and trended toward significant improvement at 5 years (p = 0.027). This study indicated that the BioPoly implant was safe, provided significant improvement starting at 6 months and continuing to 5 years, and provided greater improvement than microfracture for some outcome measures. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Morphometric Analysis of Adult Dry Patellae: A Cross-sectional Study

Introduction: The patella is the largest sesamoid bone in the body, which develops within the tendon of the quadriceps femoris muscle. It is a flat, distally tapered, and proximally curved bone. The morphometric study of the patella is important for orthopaedic surgeries. Aim: To conduct a morphometric analysis of the adult dry patella. Materials and Methods: A cross-sectional observational study was conducted on 50 dry human patellae from both the right and left sides of unknown gender. These specimens were obtained from the “Bone Library” of the Department of Anatomy, TN Medical College, and Nair Hospital, Mumbai, Maharashtra, India, during the period from December 2022 to February 2023. Patellar length, width, thickness, as well as the width of the articular facet, were measured using an electronic digital vernier caliper. Mean, standard deviations, and p-value were calculated using the Statistical Package for Social Sciences (SPSS) version 26.0. Patellar parameters between the right and left sides were compared, and an unpaired student's t-test was applied. Results: The mean height, width, and thickness of the right patellae were 42.08±3.44 mm, 45.20±4.35 mm, and 18.85±2.16 mm, respectively, while those of the left patellae were 42.68±3.52 mm, 45.00±2.57 mm, and 19.56±1.62 mm, respectively. The mean width of the medial and lateral articular facets of the right patellae were 18.65±2.65 mm and 23.20±2.20 mm, respectively, while those of the left patellae were 19.10±2.25 mm and 22.61±1.69 mm, respectively. Conclusion: The present study evaluates different dimensions such as length, width, thickness, and the articular facet of the patella. These findings will be helpful in designing knee implants and during reconstructive surgeries related to the knee.

Estimation and Comparison of Knee Joint Contact Forces During Heel Contact and Heel Rise Deep Squatting.

Increased knee flexion is required for deep squatting in the daily life of the non-western population as well as in many sports activities. The purpose of this study was to estimate as well as to compare knee joint contact forces during heel contact (HC) and heel rise (HR) deep squatting in 10 healthy young Indian participants. Kinematic data were captured using a 12-camera Motion Analysis system. Kinetic data were collected using two Kistler force plates. EMG of 6 lower limb muscles was monitored by Noraxon wireless EMG. OpenSim musculoskeletal model was customized to increase the maximum knee flexion capability of the existing model and knee joint contact forces were estimated. A significant difference in tibiofemoral (p < 0.001) as well as patellofemoral (p = 0.006) knee joint contact force was observed between HC and HR squatting. The resultant maximum tibiofemoral KJCF was 5.9 (± 0.54) times body weight (BW) and 5.3 (± 0.6) BW for the HC and HR, respectively. The resultant maximum patellofemoral KJCF was 7.8 (± 0.57) BW and 7.1 (± 0.73) BW for the HC and HR, respectively. The findings can provide implications for physiotherapists to design rehabilitation exercise protocols, exercise professionals, and the development of high flexion knee implants. The online version contains supplementary material available at 10.1007/s43465-022-00798-y.

205. IL-1 β gene (+3954C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms associate with early aseptic loosening of hip and knee arthroplasties but not with implants infection

Abstract Background Aseptic prosthetic loosening (APL) and prosthetic joint infections (PJI) are frequent complications of hip and knee implants. Polymorphisms of cytokines and nitric oxide (NO), key inflammatory molecules in APL and PJI pathogenesis, could explain individual susceptibility to these complications. Methods Three cytokines (IL-1-a, IL-1-β, TNF-α) and two nitric oxide synthase (NOS2, NOS3) genes polymorphisms were genotyped in 77 APL and 117 PJI patients and 145 controls with aseptic hip or knee implants lasting &amp;gt; 16 years. Plasma cytokines and nitrate-nitrite (NOx) levels were measured. Results The TT genotype and T allele of the (+3954C/T, exon 5, rs1143634) IL-1β polymorphism were more frequent in APL patients compared to controls (p=0.03 and p=0.02, respectively). No genotypic associations in PJI patients were observed. S. epidermidis was their most frequently isolated microorganism (39.3%). Plasma IL-6, TNF-α and NOx were significantly different between APL and controls (p&amp;lt; 0.0001). Plasma IL-1β and IL-6 were significantly higher in APL T allele carriers vs. non-carriers (p&amp;lt; 0.03). Knee implant (HR 2.488, 95% CI 1.307-4.739, p=0.005), male gender (HR 2.252, 95% CI 1.121-4.525, p=0.023), carriages of the TT genotype of the (+3954C/T) IL-1β polymorphism (HR 3.704, 95% CI 1.274-10.753, p=0.016) and AA genotype of the (exon 22) NOS2 polymorphism (HR 3.509, 95% CI 1.266-9.709, p=0.016) were independently associated with a shorter implant survival by Cox regression. Conclusion Genotyping of IL-1β (+3954C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms could be useful as predictors of early hip or knee APL. Disclosures All Authors: No reported disclosures.

Computational dosimetry in MRI in presence of hip, knee or shoulder implants: do we need accurate surgery models?

Objective. To quantify the effects of different levels of realism in the description of the anatomy around hip, knee or shoulder implants when simulating, numerically, radiofrequency and gradient-induced heating in magnetic resonance imaging. This quantification is needed to define how precise the digital human model modified with the implant should be to get realistic dosimetric assessments. Approach. The analysis is based on a large number of numerical simulations where four ‘levels of realism’ have been adopted in modelling human bodies carrying orthopaedic implants. Main results. Results show that the quantification of the heating due to switched gradient fields does not strictly require a detailed local anatomical description when preparing the digital human model carrying an implant. In this case, a simple overlapping of the implant CAD with the body anatomy is sufficient to provide a quite good and conservative estimation of the heating. On the contrary, the evaluation of the electromagnetic field distribution and heating caused by the radiofrequency field requires an accurate description of the tissues around the prosthesis. Significance. The results of this paper provide hints for selecting the ‘level of realism’ in the definition of the anatomical models with embedded passive implants when performing simulations that should reproduce, as closely as possible, the in vivo scenarios of patients carrying orthopaedic implants.

About 3D Printability of Thermoplastic Collagen for Biomedical Applications.

With more than 1.5 million total knee and hip implants placed each year, there is an urgent need for a drug delivery system that can effectively support the repair of bone infections. Scaffolds made of natural biopolymers are widely used for this purpose due to their biocompatibility, biodegradability, and suitable mechanical properties. However, the poor processability is a bottleneck, as highly customizable scaffolds are desired. The aim of the present research is to develop a scaffold made of thermoplastic collagen (TC) using 3D printing technology. The viscosity of the material was measured using a rheometer. A 3D bioplotter was used to fabricate the scaffolds out of TC. The mechanical properties of the TC scaffolds were performed using tension/compression testing on a Zwick/Roell universal testing machine. TC shows better compressibility with increasing temperature and a decrease in dynamic viscosity (η), storage modulus (G'), and loss modulus (G″). The compressive strength of the TC scaffolds was between 3-10 MPa, depending on the geometry (cylinder or cuboid, with different infills). We have demonstrated for the first time that TC can be used to fabricate porous scaffolds by 3D printing in various geometries.

MT42 Oxidized Zirconium Use in Primary Joint Arthroplasty: A 90-Day Episode of Care Analysis in a Large US Metropolitan Statistical Area (MSA) for Elective Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA)

Centers for Medicare and Medicaid Services has made hospitals accountable for better clinical and economical outcomes of total joint arthroplasty by introducing the Comprehensive Care for Joint Replacement Model. The objective of this study was to evaluate 90-day outcomes and costs of using Oxidized Zirconium (OxZr)1 knee and hip implants compared to non-OxZr from the New York-Newark-Jersey MSA.

Systemic Metal Ion Concentrations in Patients With Hip and Knee Megaprostheses: A Prospective Cohort Study.

Local tissue and serum metal ions have been shown to be elevated in some metal-on-metal and metal-on-polyethylene joint replacements. Local elevations have been linked to adverse local tissue reactions in some patients, and systemic elevation has been less commonly implicated cardiac and neurologic issues. Using a prospective study design, we aimed to identify the changes in serum metal ion levels after hip or knee megaprosthesis reconstruction. Furthermore, we will evaluate the occurrence of adverse effects and complications, possibly linked to metal ion elevation. Fourteen consecutive patients receiving a Modular Universal Tumor Revision System megaprosthesis were enrolled. Blood samples were collected preoperatively and postoperatively to determine the serum ion concentrations of aluminum, chromium, cobalt, and silver. To evaluate the safety of the megaprostheses and the subsequently possible related (elevated) serum metal ion concentrations, all adverse effects and complications were registered until last outpatient clinic visit at the time of this study. Compared to the preoperative median serum concentrations, the postoperative median serum concentrations of chromium, silver, and cobalt increased 11-fold, 62-fold, and 64-fold, respectively. The median serum concentration of aluminum increased with 16%. Elevations were primarily noted in patients with knee prostheses. Eight patients had no adverse effects or complications during the period between preoperative and postoperative blood sampling. One adverse effect directly related to the serum metal ion concentrations, namely argyria, was observed. This study documents significantly elevated concentrations of the metal ions, but only one adverse effect directly related to the metal ion concentrations was observed. Future studies are needed to further assess the impact of elevated metal ion levels after megaprostheses, specifically knee implants, which are metal-on-metal.

Development of Ti–Ta–Nb–Mo–Zr high entropy alloy by μ-plasma arc additive manufacturing process for knee implant applications and its biocompatibility evaluation

It describes development of equiatomic Ti–Ta–Nb–Mo–Zr HEA by μ-plasma arc additive manufacturing process for knee implant applications, its microstructure study and in-vitro biocompatibility evaluation using cell viability, released metallic ions, and corrosion behaviour. Cell viability was evaluated by treating HeLa, HEK-293, and BHK cells with 20, 40, 60, and 100 μl concentrations of prepared media for the developed HEA for 24, 48, 72 h incubation durations. Released amounts of Ti, Ta, Nb, Mo, and Zr ions were estimated in 4.4; 5.4; and 7.4 pH value simulated body fluid solution (SBF) for immersion durations of 1, 3, and 7 weeks. Corrosion behaviour was studied in 4.4; 5.4; and 7.4 pH value SBF solution at 37 °C. Ti–Ta–Nb–Mo–Zr HEA consists of BCC major and minor phases having fine dendritic and inter-dendritic structure. Average % cell viability decreased with increase in prepared media concentration. Overall average values of viability for HeLa, HEK-293, and BHK cells treated with prepared media are 90%; 88%; and 92% respectively. BHK cells showed maximum cell viability at each media concentration and for each incubation duration. Ti–Ta–Nb–Mo–Zr HEA did not harm appearance of HeLa, HEK-293, and BHK cells. Overall averaged released amounts of Ti, Ta, Nb, Mo, and Zr ions are 37, 26; 57; 38, and 28 ppb respectively. Ti–Ta–Nb–Mo–Zr HEA has minimum values of all essential corrosion parameters without causing any pitting. It showed excellent biocompatibility hence referred as bio-HEA which is a new class of biomaterials for knee implants that can overcome limitations of the present materials.

Short-Term Surface Damage Mechanisms of Retrieved Highly Cross-Linked Polyethylene Patellar Components

BackgroundPrevious retrieval studies of patellar components for total knee arthroplasty focused on historical designs and polyethylene materials that are no longer clinically relevant. Therefore, this study aimed to compare revision reasons and surface damage mechanisms of conventional, gamma inert sterilized polyethylene and highly cross-linked polyethylene (HXLPE) patellar components in contemporary designs from a single manufacturer. MethodsA total of 114 gamma inert and 76 HXLPE patellar components were gathered in a multicenter orthopaedic implant retrieval program. Patient age and body mass index were similar between cohorts (P = .27 and P = .42, respectively); however, the gamma inert cohort was implanted longer (μdifference = 3.1 years; P = .005). A matched subset was created based on the total knee arthroplasty design, patellar shape, and implantation time. Revision reasons were gathered from revision operating notes, and surface damage was examined via the Hood scoring method. Differences between HXLPE and gamma inert cohorts were evaluated using Mann-Whitney U-tests. ResultsThe most common revision reasons were infection, loosening, and instability, with the most common patellar complication resulting in revision being patellar loosening for both cohorts with similar incidences for both (chi-square; P = .60, P = .59). The most common surface damage modes were burnishing, scratching, and pitting in both cohorts. Total surface damage was significantly higher in the gamma inert components (P = .02), but not in the matched subset (P = .46). ConclusionOverall, the clinical performance of HXLPE was similar to that of conventional polyethylene for patellar components with short implantation times. While this study provides much needed information on the performance of HXLPE patellae in short-term retrievals, long-term studies are still needed.

A Comparison of Wear Patterns on Retrieved and Simulator-Tested Total Knee Replacements.

Aseptic implant loosening is the most common reason for revision surgery after total knee replacement. This is associated with adverse biological reactions to wear debris from the articulating implant components. To predict the amount of wear debris generated in situ, standard wear testing of total knee replacement (TKR) is carried out before its clinical use. However, wear data reported on retrievals of total knee replacement (TKR) revealed significant discrepancies compared with standard wear simulator studies. Therefore, the aim of the present study was to compare the wear patterns on identical posterior-cruciate-retaining TKR designs by analyzing retrieved and experimentally tested implants. The identification and classification of wear patterns were performed using 21 retrieved ultra-high-molecular-weight-polyethylene (UHMW-PE) inserts and four sets of inserts of identical design and material tested in a knee wear simulator. These four sets had undergone different worst-case conditions and a standard test in a wear simulator according to ISO 14243-1. Macroscopic and microscopic examinations of the polyethylene inserts were performed, including the determination of seven modes of wear that correspond to specific wear patterns, the calculation of wear areas, and the classification of the damage over the whole articulating area. Retrieved and standard wear simulator-tested UHMW-PE inserts showed significant differences in wear area and patterns. The total wear areas and the damage score were significantly larger on the retrievals (52.3% versus 23.9%, 32.7 versus 22.7). Furthermore, the range of wear patterns found on the retrievals was not reproducible in the simulator-tested inserts. However, good correspondence was found with the simulator-tested polyethylene inserts under worst-case conditions (third body wear), i.e., deep wear areas could be replicated according to the in vivo situation compared with other wear test scenarios. Based on the findings presented here, standard simulator testing can be used to directly compare different TKR designs but is limited in the prediction of their in situ wear. Preclinical wear testing may be adjusted by worst-case conditions to improve the prediction of in situ performance of total knee implants in the future.

IL-1 β gene (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms associate with early aseptic loosening of arthroplasties

Aseptic prosthetic loosening (APL) and prosthetic joint infections (PJI) are frequent complications of hip and knee implants. Polymorphisms of cytokines and nitric oxide (NO), key inflammatory molecules in APL and PJI pathogenesis, could explain individual susceptibility to these complications. Three cytokines (IL-1-a, IL-1-β, TNF-α) and two nitric oxide synthase (NOS2, NOS3) genes polymorphisms were genotyped in 77 APL and 117 PJI patients and 145 controls with aseptic hip or knee implants that were implanted for > 16 years. Plasma cytokines and nitrate-nitrite (NOx) levels also were measured. The TT genotype and T allele of (+3954 C/T, exon 5, rs1143634) IL-1β polymorphism were more frequent in APL patients compared to controls (P = 0.03 and P = 0.02, respectively). No genotypic associations in PJI patients were observed. Plasma IL-6, TNF-α and NOx were significantly different between APL and controls (P < 0.0001). Plasma IL-1β and IL-6 were significantly higher in APL T allele carriers vs. non-carriers (P < 0.03). Knee implant (HR 2.488, 95% CI 1.307–4.739, P = 0.005), male gender (HR 2.252, 95% CI 1.121–4.525, P = 0.023), carriages of the TT genotype of the (+3954 C/T) IL-1β polymorphism (HR 3.704, 95% CI 1.274–10.753, P = 0.016) and AA genotype of the (exon 22) NOS2 polymorphism (HR 3.509, 95% CI 1.266–9.709, P = 0.016) were independently associated with a shorter implant survival by Cox regression. No genotypic associations in PJI patients were observed. Genotyping of IL-1β (+3954 C/T, exon 5, rs1143634) and NOS2 (exon 22) polymorphisms could be useful as predictors of early hip or knee APL.

Corrosion and tribocorrosion behavior of ZrO2-Al2O3 composite coatings developed by plasma electrolytic oxidation for load-bearing implants

The aim of this study was to develop a ZrO 2 -Al 2 O 3 composite coating with excellent mechanical, corrosion, and tribocorrosion behaviour on Zr-2.5 Nb alloy substrate for load-bearing implants. The bipolar waveforms utilizing cathodic duty cycles of 10, 20, and 40 were applied to produce composite coatings using the plasma electrolytic oxidation in an aluminate-phosphate electrolyte bath. The ZrO 2 -Al 2 O 3 composite coatings had a net-like morphology with pores and cracks. When the cathodic duty cycle increased to 40, the Al 2 O 3 was accumulated on the surface, with an enhanced thickness (5.39 ± 0.67 µm) and compactness of the coating with significantly improved hardness (2x higher). The composite coating developed at the cathodic duty cycle of 40 displayed the highest corrosion performance in phosphate buffer saline (PBS) even after 16 weeks of immersion. Moreover, the tribocorrosion test indicated the lowest volume loss of about 0.038 mm 3 and showed no potential fall-out during the sliding test against the SiC ball. In summary, the ZrO 2 -Al 2 O 3 composite coating developed by the PEO process resulted in noticeable corrosion and tribocorrosion performance of the Zr-2.5 Nb alloy desirable for knee implants. • ZrO 2 -Al 2 O 3 composite coatings were synthesized using bipolar waveform with cathodic duty cycles of 10, 20, and 40. • The pores in outer layer of the coatings were sealing by ZrO 2 and Al 2 O 3 formation. • The D40 coating showed the best microhardness and corrosion performance in phosphate buffer saline (PBS). • The lowest volume loss was also achieved for the D40 coating in tribocorrosion test.

Antibiotic Prophylaxis Is Not Necessary for Invasive Dental Procedures in Existing Total Knee Arthroplasty Implants.

Antibiotic prophylaxis before an invasive dental procedure (IDP) for patients with preexisting knee implants has been suggested, but its use has yet to reach consensus. Therefore, we sought to examine antibiotic prophylaxis before an IDP for patients who had undergone a total knee arthroplasty (TKA). We specifically assessed 90-day to 1-year (1) periprosthetic joint infection (PJI) and (2) revision. We queried a national, all-payer database for patients undergoing primary TKA between 2010 and 2020 (n=1,952,917). We identified IDP, as defined by any procedure that involves gingival manipulation, and stratified according to antibiotic prophylaxis. A control cohort of TKA recipients without subsequent IDP was then established. All 3 cohorts were matched according to demographic and health metrics (n=496). Chi-square testing generated the odds ratio (OR) with 95% CI for postoperative PJI and revision. The odds for PJI and revision at all time points were statistically similar between antibiotic prophylaxis and no antibiotic prophylaxis (PJI: OR, 0.62; 95% CI, 0.11-4.00; P≥.479; revision: OR, ≥0.33; 95% CI, 0.03-4.00; P≥.248). Additionally, both IDP cohorts and the control cohort had similar rates of postoperative PJI (P≥.367) and revision (P≥.173) at all time points. Antibiotic prophylaxis before an IDP for TKA recipients did not decrease the risk of PJI or revision up to 1 year after the index procedure. These results support the trend by dentists and orthopedic surgeons to refrain from antibiotic prophylaxis. However, it likely has utility in patients at high risk, as suggested by current guidelines. [Orthopedics. 2023;46(2):76-81.].

Renal tubular response to titanium dioxide nanoparticles exposure

Titatinum dioxide nanoparticles (TiO2-NPs) are frequently used in several areas. Titanium alloys are employed in orthopedic and odontological surgery (such as hip, knee, and teeth implants). To evaluate the potential acute toxic effects of titanium pieces implantations and in other sources that allow the systemic delivery of titanium, parenteral routes of TiO2-NPs administration should be taken into account. The present study evaluated the impact of subcutaneous administration of TiO2-NPs on renal function and structure in rats. Animals were exposed to a dose of 50 mg/kg b.w., s.c. and sacrificed after 48 h. Titanium levels were detected in urine (135 ± 6 ηg/mL) and in renal tissue (502 ± 40 ηg/g) employing inductively coupled plasma mass spectrometry. An increase in alkaline phosphatase activity, total protein levels, and glucose concentrations was observed in urine from treated rats suggesting injury in proximal tubule cells. In parallel, histopathological studies showed tubular dilatation and cellular desquamation in these nephron segments. In summary, this study demonstrates that subcutaneous administration of TiO2-NPs causes acute nephrotoxicity evidenced by functional and histological alterations in proximal tubule cells. This fact deserves to be mainly considered when humans are exposed directly or indirectly to TiO2-NPs sources that cause the systemic delivery of titanium.