Aim. The use of medical devices has grown significantly over the last decades, and has become a major part of modern medicine and our daily life. Infection of implanted medical devices (biomaterials), like titanium orthopaedic implants, can have disastrous consequences, including removal of the device. For still not well understood reasons, the presence of a foreign body strongly increases susceptibility to infection. These so-called biomaterial-associated infections (BAI) are mainly caused by Staphylococcus aureus and Staphylococcus epidermidis. Formation of biofilms on the biomaterial surface is generally considered the main reason for these persistent infections, although bacteria may also enter the surrounding tissue and become internalized within host cells. To prevent biofilm formation using a non-antibiotic based strategy, we aimed to develop a novel permanently fixed antimicrobial coating for titanium devices based on stable immobilized quaternary ammonium compounds (QACs). Method. Medical grade titanium implants (10×4×1 mm) were dip-coated in a solution of 10% (w/v) hyperbranched polymer, subsequently in a solution of 30% (w/v) polyethyleneimine and 10 mM sodium iodide, using a dip-coater, followed by a washing step for 10 min in ethanol. The QAC-coating was characterized using water contact angle measurements, scanning electron microscopy, FTIR, AFM and XPS. The antimicrobial activity of the coating was evaluated against S. aureus strain JAR060131 and S. epidermidis strain ATCC 12228 using the JIS Z 2801:2000 surface microbicidal assay. Lastly, we assessed the in vivo antimicrobial activity in a mouse subcutaneous implant infection model with S. aureus administered locally on the QAC-coated implants prior to implantation to mimic contamination during surgery. Results. Detailed material characterization of the titanium samples showed the presence of a homogenous and stable coating layer at the titanium surface. Moreover, the coating successfully killed S. aureus and S. epidermidis in vitro. The QAC-coating strongly reduced S. aureus colonization of the implant surface as well as of the surrounding tissue, with no apparent macroscopic signs of toxicity or inflammation in the peri-implant tissue at 1 and 4 days after implantation. Conclusions. An antimicrobial coating with stable quaternary ammonium compounds on titanium has been developed which holds promise to prevent BAI. Non-antibiotic-based antimicrobial coatings have great significance in guiding the design of novel antimicrobial coatings in the present, post-antibiotic era

The need for a more durable, metal free, non-osteolytic particle generating material in Total Hip Replacement (THR) is urgently required to reduce revision surgeries. Current used materials; ceramic, metal and UHMWPE remain discrepant for long-term use. Polyimide (MP-1™) is a high performance biopolymer, originating from aerospace industry. MP-1™ is heat resistant, highly cross-linked and exhibits a self-lubrication property required for bearings and articulating joints. Being resistant to fatigue, creep and chemicals and serializable by autoclave or irradiation, MP-1™ is ideal for medical devices. Finalizing pre-clinical testing, two patients were implanted 13 years ago after informed consent. A PM (Post Mortem) retrieval at 6.5 years, showed no measureable wear, a bland synovium, and no osteoclastic or bone marrow reaction. The 13Y patients' hip, a revision from Polyethylene wear to MP-1™, has an unchanged radiograph and is fully active (Fig. 1). The Ethical Committee approved 100 patients with a single surgeon (PJB) post-marketing trial running Delta ceramic femoral ball against MP-1™ liner. Age range is from 81 to 33 years. The younger patients now being offered MP-1™, in view of the retrieval data. The MP-1™ acetabular liner is 4mm thick, as currently used in a LIMA PF shell, which replaces polyethylene, ceramic or dual mobility options. Out of the 78 enrolled patients, 52 patients have the implant for more than 5 years. The only “Complications” in a few patients was an initial squeak which spontaneously disappears by 10 days and never returns. This is likely due to reduced clearance between head and liner and likely easily correctable. There have been no dislocations or restrictions on activity level. Oxford and Harris Hip scores along with radiology, blood and clinical examination are collected during follow-up. MP-1™ liner on Delta ceramic head in THA, or in the future with MP-1 head, looks very promising with advantages of ease of sterilization, insignificant wear, no tissue reactivity and ability to have thin section and larger femoral heads if desired for larger range of motion. MP-1™ biomaterial is used for other medical devices as well such as dental implants and trauma nails, plates and screws. For any figures or tables, please contact the authors directly

This paper describes how advances in three-dimensional printing may benefit the military trauma patient, both deployed on operations and in the firm base. Use of rapid prototype manufacturing to produce a 3D representation of complex fractures that can be held and rotated will aid surgical planning within multidisciplinary teams. Patient-clinician interaction can also be aided using these graspable models. The education of military surgeons could improve with the subsequent accurate, inexpensive models for anatomy and surgical technique instruction. The developing sphere of additive manufacturing (3D printing functional end-use components) lends itself to further advantages for the military orthopaedic surgeon. Military trauma patients could benefit from advances in direct metal laser sintering which enable the manufacture of complex surfaces and porous structures on bio-metallic implants not possible using conventional manufacturing. “Bio-printing” of tissues mimicking anatomical structures has potential for military trauma patients with bone defects. Deployed surgeons operating on less familiar fracture sites could benefit from three-dimensionally printing patient-specific medical devices. These can make operating technically easier, reducing radiation exposure and operating time. Further ahead, it may be possible to contemporaneously 3D print medical devices unavailable from the logistics chain whilst operating in the deployed environment

Nowadays, foot switches are used in almost every operating theatre to support the interaction with medical devices. Foot switches are especially used to release risk-sensitive functions of e.g. the drilling device, the high-frequency device or the X-ray C-arm. In general, the use of foot switches facilitates the work, since they enable the surgeon to use both hands exclusively for the manipulation within the operation procedures. Due to the increasing number of (complex) devices controlled by foot switches, the surgeons face a variety of challenges regarding usability and safety of these human-machine-interfaces. In the future, the approach of integrated medical devices in the OR on the basis of the open communication standard IEEE 11073 gives the opportunity to provide a central surgical cockpit with a universal foot switch for the surgeon, enabling the interaction with various devices different manufacturers. In the framework of the ongoing OR.NET initiative founded on the basis of the OR.NET research project (2012–2016) a novel concept for a universal foot switch (within the framework of a surgical workstation) has been developed in order to optimise the intraoperative workflow for the OR-personnel. Here, we developed three wireless functional models of a universal foot switch together with a standardised modular interface for visual feedback via a central surgical cockpit display. Within the development of our latest foot switch, the requirements have been inter alia to provide adequate functionalities to cover the needs for the interventions in the medical disciplines orthopaedic surgery, neurosurgery and ENT. The evaluation has been conducted within an interaction-centered usability analysis with surgeons from orthopaedics, neurosurgery and ENT. By using the Thinking Aloud technique in a Wizard-of-Oz experiment the usability criteria effectiveness, learnability and user satisfaction have been analysed. Regarding learnability 83.25% of the subjects stated that the usage of the universal foot switch is easy to learn. An average of 77,2% of users rated the usability of the universal foot switch between good and excellent on the SUS scale. The intuitiveness of the graphical user interface has been approved with 91.75% and the controllability with 83.25%. Finally, 86% of the subjects stated a high user satisfaction

Thumb carpometacarpal (CMC) arthritis is a common and disabling condition that can be treated with an operative procedure. Before operative measures, patients typically undergo conservative treatment utilizing methods such as physical therapy and injections. This study aims to determine what clinical modalities are being used for preoperative evaluation and nonoperative therapy and the associated cost prior to operative intervention. We queried Truven Market Scan, a large insurance provider database to identify patients undergoing CMC arthroplasty from 2010 to 2017. Patients were identified by common Current Procedural Terminology (CPT) codes for CMC arthroplasty. All associated CPT codes listed for each patient during the 1 year period prior to operative intervention were collected and filtered to only include those codes associated with the ICD-9/10 diagnosis codes relating to CMC arthritis. The codes were then categorized as office visits, x-ray, injections, physical therapy, medical devices, and preoperative labs. The frequency and associated cost for each category was determined. There were 44,676 patients who underwent CMC arthroplasty during the study period. A total of $26,319,848.36 was charged during the preoperative period, for an average of $589.13 per patient. The highest contributing category to overall cost was office visits (42.1%), followed by injections (13.5%), and then physical therapy (11.1%). The most common diagnostic modality was x-ray, which was performed in 74.7% of patients and made up 11.0% of total charges. Only 49% of patients received at least one injection during the preoperative period and the average number of injections per patient was 1.72. Patients who were employed full time were more likely to receive two or more injections prior to surgery compared to patients who had retired (47% of full-time workers; 34% of retirees). The modalities used for the preoperative evaluation and conservative treatment of CMC arthritis and the associated cost are important to understand in order to determine the most successful and cost-effective treatment plan for patients. Surprisingly, despite the established evidence supporting clinical benefits, many patients do not undergo corticosteroid injections. With office visits being the largest contributor to overall costs, further inquiry into the necessity of multiple visits and efforts to combine visits, can help to reduce cost. Also, with the advent of telemedicine it may be possible to reduce visit cost by utilizing virtual medicine. Determining the best use of telemedicine and its effectiveness are areas for future investigation

In light of recent regulatory initiatives, medical devices now require additional clinical evidence to prove their safety and efficacy. At the same time, patients' own assessment of their devices' function and performance has gained in importance. The collection of these data allows for a more comprehensive picture of clinical outcomes and complications following total knee arthroplasty (TKA). These trends have led researchers to search for new methods of acquiring, interpreting and disseminating patient-reported outcome measurements (PROMs). The current study assesses the feasibility of a digital platform for collecting PROMs that was recently adapted for TKA patients. It sought to determine patient engagement, survey completion rates, and satisfaction with this platform. Eighty-two patients (mean age, 63.7 years, 59% females) scheduled for TKA were enrolled from one US and six UK sites between January 12, 2018 and April 30, 2018. Patients were supplied with a mobile application (app) that collects a variety of PROMs, including four domains based on the Patient-Reported Outcome Information System (PROMIS™): physical function, depression, pain interference and pain behavior. The platform electronically administers questionnaires using computer-adaptive tests (CATs), which reduce the burden on patients by tailoring follow-up questions to account for their previous answers. Satisfaction with the app was assessed in subset of patients who evaluated its ease-of-use (n=45), likelihood that they would recommend it to family/friends (n=35), and whether they successfully used the information it provided during their recovery (n=31). These scores were taken on a 1 to 10 (worst to best) scale. Patients demonstrated regular engagement with the platform, with 73% using the app at least once a week. Weekly engagement remained high throughout the seven-week post-operative period (Figure 1). There was a 69% completion rate of all PROMIS™ CAT surveys during the study. The four PROMIS™ CAT domains had similar survey completion rates (Figure 2). The subset of patients queried regarding their satisfaction with the app gave it favorable mean scores for ease-of-use (8.8), likelihood to recommend to a family member or friend (8.1), and their success at using its information to improve their recovery (7.4). Initial results support this digital platform's potential for successfully and efficiently collecting large volumes of PROMs. Patients reported high levels of engagement and satisfaction. For any figures or tables, please contact authors directly

Tungsten has been increasing in demand for use in manufacturing and recently, medical devices, as it imparts flexibility, strength, and conductance of metal alloys. Given the surge in tungsten use, our population may be subjected to elevated exposures. For instance, embolism coils made of tungsten have been shown to degrade in some patients. In a cohort of breast cancer patients who received tungsten-based shielding for intraoperative radiotherapy, urinary tungsten levels remained over tenfold higher 20 months post-surgery. In vivo models have demonstrated that tungsten exposure increases tumor metastasis and enhances the adipogenesis of bone marrow-derived mesenchymal stem cells while inhibiting osteogenesis. We recently determined that when mice are exposed to tungsten [15 ppm] in their drinking water, it bioaccumulates in the intervertebral disc tissue and vertebrae. This study was performed to determine the toxicity of tungsten on intervertebral disc. Bovine nucleus pulposus (bNP) and annulus fibrosus (bAF) cells were isolated from bovine caudal tails. Cells were expanded in flasks then prepared for 3D culturing in alginate beads at a density of 1×10. ∧. 6 cells/mL. Beads were cultured in medium supplemented with increasing tungsten concentrations in the form of sodium tungstate [0, 0.5, 5, 15 ug/mL] for 12 days. A modified GAG assay was performed on the beads to determine proteoglycan content and Western blotting for type II collagen (Col II) synthesis. Cell viability was determined by counting live and dead cells in the beads following incubation with the Live/Dead Viability Assay kit (Thermo Fisher Scientific). Cell numbers in beads at the end of the incubation period was determined using Quant-iT dsDNA Assay Kit (Thermo Fisher Scientific). Tungsten dose-dependently decreased the synthesis of proteoglycan in IVD cells, however, the effect was significant at the highest dose of 15 ug/mL. (n=3). Furthermore, although tungsten decreased the synthesis of Col II in IVD cells, it significantly increased the synthesis of Col I. Upregulation of catabolic enzymes ADAMTS4 and −5 were also observed in IVD cells treated with tungsten (n=3). Upon histological examination of spines from mice treated with tungsten [15 ug/mL] in their drinking water for 30 days, disc heights were diminished and Col I upregulation was observed (n=4). Cell viability was not markedly affected by tungsten in both bNP and bAF cells, but proliferation of bNP cells decreased at higher concentration. Surprisingly, histological examination of IVDs and gene expression analysis demonstrated upregulation of NGF expression in both NP and AF cells. In addition, endplate capillaries showed increases in CGRP and PGP9.5 expression as determined on histological sections of mouse IVDs, suggesting the development of sensory neuron invasion of the disc. We provide evidence that prolonged tungsten exposure can induce disc fibrosis and increase the expression of markers associated with pain. Tungsten toxicity may play a role in disc degeneration disease

The ATTUNE™ Knee System (DePuy Synthes) comprises of a tibial insert that is made from AOX™, an antioxidant-stabilized polyethylene. The antioxidant used in AOX is pentaerythritol tetrakis [3-(3, 5-di-tertiary butyl-4-hydroxyphenyl)] propionate (PBHP). A biological risk assessment of the degradation products arising from PBHP has been performed. This assessment focuses on the requirements of ISO 10993–1:2009, ISO 14971:2007, and the Medical Device Directive 93/42/EEC. Because the orthopedic implant is a permanent implant, consideration has been given to all relevant endpoints defined by ISO 10993–1 Biological evaluation of medical devices – Part 1: Evaluation and testing within a risk management process. Comprehensive biocompatibility testing including long-term (26 weeks) subcutaneous implantation has been conducted which confirms the biosafety of the polyethylene compound[1]. In addition to the biological safety testing completed, the overall safety and the associated toxicological risk of exposure to degradation products of PBHP has been given due consideration. The guidelines for the Threshold for Toxicological Concern (TTC) provided by The Product Quality Research Institute (PQRI) Leachables and Extractables Working Group were used in the assessment[2]. This working group is a collaboration of chemists and toxicologists from the U.S. Food and Drug Administration (FDA), industry, and academia. The TTC principle allows safety assessment in the absence of substance-specific hazard data, based on very low levels of exposure to that substance. A Margin of Safety (MOS) is calculated as the ratio of the threshold safety value to the actual exposure quantities determined and used in the assessment. A MOS value greater than 1 is typically judged by risk assessors and regulatory bodies to be unlikely to cause harm and the risk may be considered low. The identity of the degradation products as well as the corresponding 30-day leachable quantities from a water:acetone extraction media has been previously reported [3] and provided here (Table 1). The amount of leachables determined from Table 1 for all products were well below the TTC of 150 ng/device and hence no toxicological risks were identified for these compounds. In order to further examine the toxicological risk assessment, aggressive extraction using Dynamic Head Space (DHS) extraction was done and analytical testing was performed on the degradation products of PBHP using gas chromatography/mass spectrometry (GC /MS). These estimated quantities along with literature information from biological safety studies of the chemicals that were identified from the quantitative GC/MS analysis of degradation products of PBHP were used in the review and toxicological assessment per the methodology described in ISO 14971 and ISO 10993–18. The extraction and analysis confirmed the same sixteen compounds previously identified. The quantities and the calculated margins of safety are summarized (Table 2). In conclusion, upon review of actual test results of PBHP degradation products (Table 1), there is little probability that these organic degradation products would cause a systemic reaction and not be safe. Thus, the potential biological hazards identified in ISO 10993–1:2009 due to the quantified leachables have been verified to be minimal with a high Margin of Safety relative to the Threshold of Toxicological Concern

There has been considerable activity in the past year as a result of the Justice Department Investigation into the medical device industry. There has been an over reaction by many which may negatively impact future research, development and reporting of clinical outcomes. This paper will review some of these activities. A review of professional standards and guidelines has been conducted looking at health care compliance issues as they related to commercial relationships, professional medical societies, individual surgeons, and health care workers with specific focus on disclosure. Within any important issue, there are always aspects no one wishes to discuss: conflict of interest. Perception of a conflict of interest is often enough to bring about a review of activity. Overreaction has occurred as a result of government intervention into the medical device industry. Continuing medical education, professional societies by-laws, clinical/surgical publications, medical/legal exposure, product research, development and industry marketing activities have all been impacted. When professionals fail to provide a proper review process on standards and guidelines on ethical behavior they set themselves up for government oversight and restrictions on their behavior. Be informed and disclose. Know what, when and how to disclose. Protect yourself, no one else will

Aim. In private healthcare facilities, the access to a specialized infectious disease (ID) advice is difficult. More, the lack of traceability is problematic and harmful for treatment and follow-up. We have tested an information technology (IT) application to improve medical transmission and evaluate an interdisciplinary ID activity. Methods. In November 2015, three ID physicians (IDP) created an interdisciplinary activity, visiting patients and giving phone advices among ten private healthcare facilities. They are members of the complex bone and joint infection unit of the community hospital where they are attached. Since September 2016, each advice was prospectively recorded on a protected online information system. These data are available for consultation and modification by the three IDP. It is the first descriptive analysis of this database. Results. From September 2016 to February 2017, 887 advices from 573 inpatients were collected. Median age was 69 years old and 56% of patients were male (n=320). Comorbidity was notified in 329 patients (57%): presence of a medical device (n=154), active neoplasia (n=76), mellitus diabetes (n=38) and renal failure (n=38) were the most common. Patients were hospitalized in a surgery unit in 49% of cases and of which 69% was the orthopaedic unit. By frequency, type of infection was prosthetic joint (n=111) and osteosynthesis device infection (n=67), urinary tract infection (n=57), skin infection (n=44), and catheter device infection (n=43). The presence of multidrug resistant bacteria was notified in 63 patients. Antibiotics were already administered before the first advice in 62% of patients. Advices were given after a medical consultation in the clinic in 353 cases (40%) and after a phone call with the physician in charge of the patient in 523 cases (60%). Antibiotics were disrupted or not introduced for 126 advices (14%), introduced for 133 advices (15%), modified in 337 advices (38%) and maintained unchanged in 291 advices (33%). New evaluation was effective for 171 patients (30%). Multidisciplinary meeting was requested for 54 patients. Conclusion. Use of an information system for interdisciplinary and multisite ID activity has permitted with a better traceability to improve management of these septic patients, facilitate storage and transmission of medical information. It is a first overview of ID activity in private healthcare facilities and these tools appear essential in the development of such activity and for public health policy

Despite the vast quantities of published artificial intelligence (AI) algorithms that target trauma and orthopaedic applications, very few progress to inform clinical practice. One key reason for this is the lack of a clear pathway from development to deployment. In order to assist with this process, we have developed the Clinical Practice Integration of Artificial Intelligence (CPI-AI) framework – a five-stage approach to the clinical practice adoption of AI in the setting of trauma and orthopaedics, based on the IDEAL principles (https://www.ideal-collaboration.net/). Adherence to the framework would provide a robust evidence-based mechanism for developing trust in AI applications, where the underlying algorithms are unlikely to be fully understood by clinical teams.

Cite this article: Bone Joint Res 2024;13(9):507–512.

INTRODUCTION. Retrieval analysis is an important aspect of medical device development. Examination of retrieved devices allows device developers to close the design loop, understand the performance of devices, and validate assumptions made and methods used during preclinical testing. We provide an overview of the implant retrieval analysis performed at the Implant Research Center at Drexel University on reverse total shoulder systems retrieved after short to medium term implantation. METHODS. We have examined 18 reverse total shoulders, retrieved at revision surgery after short to mid-term implantation (average 1.4 years, maximum 3.3 years). The average age at revision was 71 years old (st dev 11 years). Our evaluations included analysis of glenosphere bearing surface damage, evaluation of tribocorrosion at the modular junctions, visual assessment of polyethylene humeral bearing surface damage, quantitative analysis of polyethylene wear. RESULTS and DISCUSSION. We observed that polyethylene wear of the humeral bearing surface (mode I) is limited in the short to medium term and that wear and damage of revised devices are dominated by unintentional contact and impingement of the inferior rim of the bushing (mode II damage). This was in agreement with a previously published analysis of a smaller cohort (Figure 1). Scratching and damage of the glenosphere was a common observation, particularly in patients with a history of instability. The observed increase in glenosphere roughness was similar to that reported in association with hip dislocation (Figure 2). Damage at the modular junctions was limited and dominated by fretting rather than corrosive damage. Mild to moderate fretting was commonly observed at the interface between the glenosphere and metaglene (Figure 3). These observations provide an increased understanding of device performance and potential failure modes. Further studies will be necessary to characterize the long term performance of reverse total shoulder systems

Introduction. We have previously demonstrated that peroxide crosslinked vitamin E-blended UHMWPE maintains its clinically-required wear and mechanical properties [1]. This material can potentially be used as an irradiation-free bearing surface for TJA. However, using organic peroxides in medical devices requires a thorough examination of tissues in contact with the implant. For this study we crosslinked polyethylene using five times the needed concentration of peroxide (2,5-Dimethyl-2,5-di(t-butylperoxy)-hexyne-3 or P130), followed by implantation to determine implant biocompatibility, and pre and post implant peroxide residual contents. Methods. The study was performed after institutional approval following ISO standard 10993–6. Study groups: not crosslinked (0.2 (1050) VE), crosslinked (0.2 VE (1050)/5% P130) and crosslinked-high temperature melted (HTM) (0.2 VE (1050)/5% P130). Materials were blended and consolidated, machined (2.5 diameter × 2.5 cm height), sterilized and implanted in the dorsum New Zealand white rabbits. Pre and post implantation FTIR was performed. Two samples were implanted in each rabbit; n=6 samples were included for each group. After 4 weeks, samples were explanted, analyzed using FTIR, and subcutaneous tissues processed for histological analysis. Results. FTIR absorbances at 914cm. −1. , 1169cm. −1. , and the OH absorbance at 3450cm. −1. showed differences between materials (Fig 1A). There was a significant increase in the absorbance at 914 for the non-crosslinked and crosslinked samples after explantation (p = 2.77E–17, p = 4.22E–23, Fig 1B). There was a significant decrease in all peroxide related absorbances after explantation for the crosslinked and HTM samples (p < 0.05, Fig 1B). Before implantation, these absorbances were significantly higher in the crosslinked and crosslinked/HTM samples than those in the non crosslinked sample (p<0.05, Fig 2A). Peroxide related absorbances of the crosslinked sample were also significantly higher than those of the crosslinked/HTM sample (p<0.05, Fig 2A). After explantation, the crosslinked samples had significantly higher absorbances than both the non crosslinked and crosslinked/HTM samples (p < 0.05, Fig 2A). All peroxide related absorbances of the crosslinked/HTM samples were significantly higher than those of the non crosslinked sample (p < 0.05, Fig 2A). The non crosslinked sample showed no significant differential between these absorbances at implantation and after retrieval. The crosslinked sample had the largest differential between the total peak absorbances before implantation and retrieval at 914cm. −1. The crosslinked/HTM samples had the largest differential between the total peak absorbances before and after implantation for both 1169cm. −1. and the OH absorbances (Fig 2B). All explants were recovered after four weeks in vivo (Fig 3A). No difference was found in the histological analysis of the tissue characterized by a synovial-like lining with signs of fibrosis around the implants (Fig 3B). Discussion. The main challenge of this study was identifying pre and postoperative implant peroxide residual peaks via FTIR. We wanted to ensure that peroxide was present in implants before implantation, to ensure their elution into tissues. Conclusions. Peroxide crosslinked polyethylene stabilized with vitamin E can potentially be used as an alternate bearing surface. Irradiation-free processing could result in cost-effectiveness and more accurate cross-linking of polyethylene implants

Abstract Detail. Interim results on a prospective, randomised, single-blinded pilot study to compare implant alignment using a patient-matched cutting guide versus a computer-assisted navigation system following total knee arthroplasty. Purpose of Study. To compare implant alignment using a patient-matched cutting guide (Visionaire) versus a computer-assisted navigation system (CAS) following total knee arthroplasty (TKA). Description of methods. Ethics approval was sought and granted by the South African Medical Association Research Ethics Committee. Patient consent for participation was obtained. Patients were randomized to TKA using Visionaire or CAS. Mechanical alignment was evaluated pre-operatively and at 3 months with a full leg X-Ray. Operative and post-operative parameters relating to resource utilization were captured. Clinical status according to the Knee Society Clinical Rating System (KSCRS) was assessed pre-operatively and at 3 months. Adverse events were noted. An independent Contract Research Organisation was used to monitor the site. Summary of results. Ten unique patients were enrolled, of whom 5 were randomized to Visionaire and 5 to CAS. Two patients in the Visionaire group have not yet reached their 3-month assessment. No significant difference in mechanical alignment between the 2 groups at 3 months was observed. The median duration of surgery was significantly shorter for the patient-matched cutting guide group across all assessed parameters (theatre time: 117 versus 150 minutes, p=0.009; operative time: 85 versus 108 minutes, p=0.0088; tourniquet time: 73 versus 99 minutes, p=0.009; and anaesthetist time: 117 versus 150 minutes, p=0.009). No other significant differences in operative or post-operative cost-drivers were noted between the 2 groups. No significant difference in KSCRS scores between the 2 groups at 3 months was observed. Two adverse were reported, one in each group, both unrelated to the medical devices, and both of which have resolved. Conclusion. While implant alignment appears consistent and comparable in both groups at 3 months, the median duration of surgery was significantly shorter for the Visionaire group. DISCLOSURE: Assistance and funding was received from Smith & Nephew

S epidermidis and P aeruginosa are recognised major biofilm pathogens in medical device contamination and chronic wounds. Within biofilms, bacteria are enclosed in a polymeric matrix that cements them to each other and to the surface and protects them by increasing resistance to host immunity, antibiotics and biocides. Staph and pseudomonas spp biofilm were grown on glass coupons for 48 hours and the coupons randomly inserted into the wound model for 24 hours and subjected to TNP and the following:. No instillation. 0.1% w/v formulated hypocholorous acid (FHA) instillation. Saline instillation. Betadine instillation. Betadine and saline instillations were for 30 minutes, while FHA was for three minutes, every eight, four and two hours per day. The biocides were at sub-lethal concentrations. The coupons were then extracted to avoid damaging the biofilms and effect of TNP was assessed by colony forming units and electron microscopy. The results show that lower frequency of instillation did not have significant effect on bacterial load for both types of bacteria. Increase in frequency of instillations resulted in no growth of pseudomonas while increase in frequency of instillations resulted in a significant decrease in growth of staph spp. Frequent flushing of the wound model resulted in a loss of biofilm bacteria for both Pseudomonas and Staph epi. The biocides combined with TNP were more effective in killing Pseudomonas compared with Staph epi

Rapid manufacturing using laser beam and/or electron beam has been applied to fabrication of artificial hip and knee joints in quite recent years. In the electron beam melting (EBM) method, the high energy electron beam effectively melts the metal powder without creating flaws such as porosities or inclusions of oxide particles during building. Thus it is found that EBM technique for rapid manufacturing of artificial hip and knee joints processes a higher possibility as the next-generation methodology for fabrication of the medical devices such as hip and knee joints. In the present study, we focus on the EBM technique. The microstructures and mechanical properties of Co-29Cr-6Mo alloy with C and N additions, produced by using EBM method, were studied using X-ray diffraction, electron back scatter diffraction, transmission electron microscope (TEM), Vickers hardness tests, and tensile tests, focusing on the influences on the build direction and the various heat treatments after build. It is found that the microstructures for the as built specimens were changed from columnar (Fig. 1a) to eqiaxed grain structure (Fig. 1c) with average grain size of approximately 10–20 μm due to the heat treatment employing the reverse transformation from a lamellar (hcp + Cr. 2. N) phase to an fcc phase. Our results will contribute to the development of biomedical Ni-free Co–Cr–Mo–N-C alloys, produced by EBM method, with refined grain size and good mechanical properties, without requiring any hot workings. Fig. 1 Inverse pole figure (IPF) maps of microstructure of samples produced by EBM method, taken by EBSD. (a) as-built, (b) after aging treatment, (c) after reverse transformation heat treatment (RT-HT)

Total joint arthroplasty is a safe and effective procedure as an end-stage treatment for arthritis. In the case of hip replacement mean patient age has decreased from sixty-eight to sixty-five years over the past eight years, raising concerns over implant longevity and the complications that occur in association with revision surgery. The dominant mode of failure of total joint replacements is aseptic loosening, which in many cases is caused by the reaction of bone to the presence of implant debris. In an attempt to increase implant longevity, bearing surfaces that minimize the volume of debris generated from the articular surface are being developed. Ultra- high molecular weight polyethylene, which has been the mainstay of arthroplasty, changing the material with which the polyethylene articulates has also been addressed in an effort to further improve wear characteristics. Oxinium is the brand family name of a material used for replacement joints manufactured by the reconstructive orthopedic surgery division of medical devices company Smith & nephew. It consists of a Zirconium alley metal substrate that transitions into a ceramic Zirconium oxide outer surface. The ceramic surface is extremely abrasion resistant compared to traditional metal implants such as cobalt chromium. It also has a lower coefficient of friction against ultra-high molecular weight polyethylene(UHMWPE), The typical counter face material used in total joint replacements. These two factors likely contribute to the significantly lower UHMWPE wear rates observed in simulator testing. Reducing UHMWPE wear is thought to decrease the risk of implant failure due to osteolysis. All ceramic material can have a similar effect in reducing wear, but are brittle and difficult to manufacture. The metal substrate of oxinium implants makes component easier to manufacture and gives them greater toughness(a combination of strength and ductility). In essence, this technology combines the abrasion resistance and low friction of a ceramic with the workability and toughness of a metal

Millions of medical devices made of synthetic or modified natural materials all trigger a similar reaction—the foreign body reaction. Biocompatibility, for materials that pass routine cytoxicity assays, is largely associated with a mild foreign body reaction. I.e. a thin, avacular, collagenous, non-adherent foreign body capsule. The implant is incorporated into a dead-zone of acellular scar. The contemporary tissue engineering paradigm would suggest that synthetic polymers and scaffolds lacking cellular, biomolecule or biomimetic elements will give this same fibrotic, avascular healing reaction. In this talk, a synthetic biomaterial will be described that readily integrates into tissue and may stimulate spontaneous reconstruction of tissue. The material is fabricated by a process called sphere-templating and it can be made from many synthetic polymers including hydrogels, silicones and polyurethanes. All pores are identical in size and interconnected. Studies from our group have shown optimal healing (as suggested by extensive vascularity and minimal fibrosis) for spherical pores of 30–40 m size. The integrative healing noted is independent of biomaterial. Similar results are observed with sphere-templated silicone rubber and pHEMA hydrogel. In addition, surface chemical modification of the hydrogel with carbonyl diimidazole, or immobilisation on the hydrogel of collagen I or laminin did not change the healing response. Also, good healing results have been seen upon implantation in skin (subcutaneous, percutaneous), heart muscle, sclera, skeletal muscle, bone and vaginal wall. We consistently find the pore spaces heavily populated by monocytic cells that stain for macrophage cell surface markers. However, at long implantation times (16 or more weeks), the ability to stain for macrophage surface markers decreases. It could be possible that these cells populating the implants are differentiating into other tissues. Thus, such materials may represent a path to cell-free tissue engineering. Others have seen similar healing results, via completely different materials strategies, generally involving biological molecules. The in vivo results from our group and related results from other groups suggest we are on the cusp of a revolution in healing, biomaterials integration and tissue reconstruction. Also, the boundaries between biomaterials and tissue engineering continue to blur

Over the past 40 years information from large institutional total joint registries have aided in patient clinical care and follow-up efforts, have helped drive improvements in clinical practice, and have been a powerful tool for generating research studies on large well documented populations of patients. Still, these efforts are limited in that they are expensive, usually reflect a single institutional experience, and results can be biased by the larger volumes or experience at the typically large academic centers which have such registries in place. National registry efforts in other countries including Scandinavia, Australia, and the UK have resulted in improved outcomes and a decreased number of revision procedures by a combination of early identification and withdrawal of poorly performing implants, altered surgical techniques, implant choices and behaviors by surgeons, changes in practices by hospitals, and modification in requirements and incentives by payors and regulatory agencies. The American Joint Replacement Registry (AJRR) is a collaborative multi-stakeholder, independent, not-for-profit 501 c3 organisation established in 2009 for data collection and quality improvement initiatives relating to total hip and knee arthroplasty. AJRR is a national registry effort with the goal of enrolling more than 90% of the over 5,000 hospitals performing nearly 1 million hip and knee arthroplasties each year in the US. AJRR is supported by contributions from the American Academy of Orthopedic Surgeons (AAOS), the American Association of Hip and Knee Surgeons (AAHKS), the Hip Society, the Knee Society, Health Insurers, Medical Device Manufacturers, and individual orthopaedic surgeons via designated contributions through the Orthopedic Research and Education Foundation (OREF). The overarching goal of AJRR is to improve arthroplasty care for patients through the collection and sharing of data on all primary and revision total joint replacement procedures in the U.S. The mission of the registry is to enhance patient safety, and improve the value of arthroplasty care. This will be accomplished by providing national benchmarks for implant, surgeon and hospital performance which serves to modify behaviors thereby decreasing the revision burden, improving outcomes and reducing costs. From the time of incorporation in 2009 up to October 2013 the AJRR has secured the participation of 218 hospitals in 47 different states in the formal enrollment process, and have level one data submission from more than 100 institutions on over 63,000 hip and knee procedures. In addition to publicly available annual reports, confidential specific individual reports for hospitals, surgeons and manufacturers will be available by subscription with an option for future confidential online direct data queries by an individual or entity regarding their own individual performance compared to national benchmark values. In summary, registry studies have provided a rich source of information for improving arthroplasty care over the past four decades, with the emergence and increasing interaction of national registries a major factor in current efforts to increase both the quality and value of the health care of entire populations. The development, support and continued expansion of a national registry in the US must remain a central focus if we wish to improve as much as possible the arthroplasty care provided to all patients in our country

Introduction. Total knee arthroplasty (TKA) prostheses are semi-constrained artificial joints. A well-functioning TKA prosthesis should be designed with a good balance between stability and mobility, meaning the femorotibial constraint of the artificial joint should be appropriate for the device's function. To assess the constraint behavior of a TKA prosthesis, physical testing is typically required, and an industrial testing standard has been developed for this purpose [1]. Computer simulation has become increasingly useful in many industries, including medical device research and development where finite element analysis (FEA) has been extensively used in stress analysis and structural evaluation. This study presents an FEA-based simulation to evaluate the femorotibial constraint behavior of TKA prosthesis, and demonstrated the effectiveness of the method by validating through physical testing. Methods. A Cruciate Retaining (CR) TKA prosthesis design (Optetrak Logic CR, Exactech, USA) was used in this study. CAD models of the implants assembled at 0° of flexion were used for the simulation. Finite element models were generated using with all materials assumed linear elastic. Boundary conditions were set up according to the ASTM F1223 standard (Figure 1). The tibial baseplate was fixed distally. A constant compressive force (710 N) was applied on the femoral component. Nonlinear Surface-Surface-Contact was defined at the femorotibial articulating surfaces. Coefficient of friction was determined from physical test. The femoral component was driven under a displacement-controlled scheme to slide along the anterior-posterior (AP) direction on the tibial insert. At each time step, constraint force occurring at the articulating surface was derived from the reaction force at the distal fixation of the tibial baseplate. A nonlinear FEA solver (NX Nastran SOL601, Siemens, USA) was used to solve the simulation. In addition, five samples of the prostheses were physically tested, and the results were compared with the simulation. Results. The simulation successfully captured the movement of contact location and pressure along the movement of the femoral component (Figure 2). The force-displacement curve predicted by the simulation exhibited a very close hysteresis loop profile as the results of physical testing (Figure 3). Using the curve slope from 0 to 5 mm to characterize the linear constraint, the simulation predicted 45.7 N/mm anteriorly and 36.4 N/mm posteriorly, which are less than 10% different from the physical testing results (46.4 N/mm anteriorly and 39.6 N/mm posteriorly). Discussion/Conclusion. This study demonstrated that the simulation was able to closely predict the femorotibial constraint behavior of the TKA prosthesis under ASTM F1223 testing. The simulation results resembled the physical testing results not only in the general curve profile but also in the magnitude of slope values. The increased difference at the far anterior region could be related to the fact that no material nonlinearity was currently considered, which could be improved in future studies. A validated simulation method could be very useful in TKA prosthesis design. Since no physical prototypes are required, design evaluation and optimization can be achieved in a much easier and faster manner