The trapeziometacarpal joint (TMCJ) is the most common hand joint affected by osteoarthritis (OA), and trapezium implant arthroplasty is a potential treatment for recalcitrant OA. This meta-analysis aimed to investigate the efficacy and safety of various trapezium implants as an interventional option for TMCJ OA. Web of Science, PubMed, Scopus, Google Scholar, and Cochrane library databases were searched for relevant studies up to May 2022. Preferred Reported Items for Systematic Review and Meta-Analysis guidelines were adhered to and registered on PROSPERO. The methodological quality was assessed by National Heart, Lung, and Blood Institute tools for observational studies and the Cochrane risk of bias tool. Subgroup analyses were performed on different replacement implants, the analysis was done via Open Meta-Analyst software and P values < 0.05 were considered statistically significant. A total of 123 studies comprising 5752 patients were included. Total joint replacement (TJR) implants demonstrate greater significant improvements in visual analogue scale pain scores postoperatively. Interposition with partial trapezial resection implants was associated with the highest grip strength and highest reduction in the Disabilities of the Arm, Shoulder, and Hand score. Revision rates were highest in TJR (12.3%), and lowest in interposition with partial trapezial resection (6.2%). Total joint replacement and interposition with partial trapezial resection implants improve pain, grip strength, and DASH scores more than other implant options. Future studies should focus on high-quality randomized clinical trials comparing different implants to accumulate higher quality evidence and more reliable conclusions

Aim. Debridement, antibiotics and implant retention (DAIR) are considered as an optimal curative treatment option for prosthetic joint infection (PJI) when the biofilm is still immature and radical debridement is achievable. There are two main groups of patients suitable for DAIR. Those with an early acute PJI and patients with acute hematogenous PJI. However, there is also a third group of early PJI resulting from a wound healing problem or leaking hematoma. These may be either high or low grade depending on the microorganisms that infected the artificial joint “per continuitatem”. Methods. We retrospectively analysed 100 successive DAIR procedures on prosthetic hip and knee joints performed between January 2010 and January 2022, from total of 21000 primary arthroplasties implanted within the same time period. We only included PJI in primary total replacements with no previous surgeries on the affected joint. Patients data (demographics, biochemical, microbiological, histopathological results, and outcomes) were collected from hospital bone and joint infection registry. The aim of surgery was radical debridement and the mobile parts exchange. The standardized antibiotic regime based on antibiofilm antibiotics. Results. The mean age of patients was 70 years (60% women, 43 hips, 57 knees) with a mean follow-up of 3 years. 45 cases were early acute or related to wound healing problems, 55 were hematogenous PJI. 25 patients received preoperative antibiotics. 6 of these were culture negative. The mean symptom duration was 7 days. Mean age of the prosthesis was 30 days for early, and 1064 days for the hematogenous group. Conclusions. In our cohort the success rate of DAIR is 94% which indicates that the protocol is highly successful in PJI with short-lasting symptoms and “debridable” joints. Antibiotic protocol violation and duration of symptoms may have a role in failures

Problem. The identification of unknown orthopaedic implants is a crucial step in the pre-operative planning for revision joint arthroplasty. Compatibility of implant components and instrumentation for implant removal is specific based on the manufacturer and model of the implant. The inability to identify an implant correctly can lead to increased case complexity, procedure time, procedure cost and bone loss for the patient. The number of revision joint arthroplasty cases worldwide and the number implants available on the market are growing rapidly, leading to greater difficulty in identifying unknown implants. Solution. The solution is a machine-learning based mobile platform which allows for instant identification of the manufacturer and model of any implant based only on the x-ray image. As more surgeons and implant representatives use the platform, the model should continue to improve in accuracy and number of implants recognized until the algorithm reaches its theoretical maximum of 99% accuracy. Market. Multiple organizations have created small libraries of implant images to assist surgeons with manual identification of unknown implants based on the x-ray, however no automated implant identification system exists to date. One of the most financially successful implant identification tools on the market is a textbook of hip implants which sells for a per unit cost of $200. Several free web-based resources also act as libraries for the manual identification of a limited number of arthroplasty implants. A number of academic and private organizations are working on the development of an automated system for implant identification, however none are available to the public. Product. Implant Identifier is mobile application which uses machine-learning to instantly detect the model and manufacturer of any common arthroplasty implant, based only on x-ray. The beta version offers a large library of implants for manual identification and is currently available for free download on iOS and Android. Its purpose is to further develop the model to its maximal theoretical accuracy, prior to official release. The beta version of the application currently has over 15,000 registered users worldwide and has the largest publicly available arthroplasty library available on the market. Over 200,000 implant images have been submitted by users to date. Timescales. The product was initially released in the form of a closed beta which became available to invited guests around 18 months ago. The current version is an open beta which can be downloaded and used by any individual. It was released roughly 12 months ago. The final rendition of the application will allow for free manual identification using the implant library, as well as subscription-based automated implant identification. The implementation, testing and release of this final subscription product is projected to be completed by Q3 2022. Funding. A small number of early investors have funded the initial research and development of the beta product; however, another round of investment will be beneficial in the final evolution of the product. This additional investment round will allow for completion of development of the identification algorithm, product dissemination, customer support, and lasting sustainability of the venture

Introduction & Aims. In other medical fields, smart implantable devices are enabling decentralised monitoring of patients and early detection of disease. Despite research-focused smart orthopaedic implants dating back to the 1980s, such implants have not been adopted into regular clinical practice. The hardware footprint and commercial cost of components for sensing, powering, processing, and communicating are too large for mass-market use. However, a low-cost, minimal-modification solution that could detect loosening and infection would have considerable benefits for both patients and healthcare providers. This proof-of-concept study aimed to determine if loosening/infection data could be monitored with only two components inside an implant: a single-element sensor and simple communication element. Methods. The sensor and coil were embedded onto a representative cemented total knee replacement. The implant was then cemented onto synthetic bone using polymethylmethacrylate (PMMA). Wireless measurements for loosening and infection were then made across different thicknesses of porcine tissue to characterise the sensor's accuracy for a range of implantation depths. Loosening was simulated by taking measurements before and after compromising the implant-cement interface, with fluid influx simulated with phosphate-buffered saline solution. Elevated temperature was used as a proxy for infection, with the sensor calibrated wirelessly through 5 mm of porcine tissue across a temperature range of 26–40°C. Results. Measurements for loosening and infection could be acquired simultaneously with a duration of 4 s per measurement. For loosening, the debonded implant-cement interface was detectable up to 10 mm with 95% confidence. For temperature, the sensor was calibrated with a root mean square error of 0.19°C at 5 mm implantation depth and prediction intervals of ±0.38°C for new measurements with 95% confidence. Conclusions. This study has demonstrated that with only two onboard electrical components, it is possible to wirelessly measure cement debonding and elevated temperature on a smart implant. With further development, this minimal hardware/cost approach could enable mass-market smart arthroplasty implants

Radiostereometric analysis (RSA) allows for precise measurement of interbody distances on X-ray images, such as movement between a joint replacement implant and the bone. The low radiation biplanar EOS imager (EOS imaging, France) scans patients in a weight-bearing position, provides calibrated three-dimensional information on bony anatomy, and could limit the radiation during serial RSA studies. Following the ISO-16087 standard, 15 double exams were conducted to determine the RSA precision of total knee arthroplasty (TKA) patients in the EOS imager, compared to the standard instantaneous, cone-beam, uniplanar digital X-ray set-up. At a mean of 5 years post-surgery, 15 TKA participants (mean 67 years, 12 female, 3 male) were imaged twice in the biplanar imager. To reduce motion during the scan, a support for the foot was added and the scan speed was increased. The voltage was also increased compared to standard settings for better marker visibility over the implant. A small calibration object was included to remove any remaining sway in post-processing. The 95% confidence interval precision was 0.11, 0.04, and 0.15 mm in the x, y, and z planes, respectively and 0.15, 0.20, and 0.14° in Rx, Ry, and Rz. Two participants had motion artifacts successfully removed during post-processing using the small calibration object. With faster speeds and stabilization support, this study found an in vivo RSA precision of ≤ 0.15 mm and ≤ 0.20° for TKA exams, which is within published uniplanar values for arthroplasty RSA. The biplanar imager also adds the benefits of weight bearing imaging, 3D alignment measurements, a lower radiation dose, and does not require a reference object due to known system geometry and automatic image registration

Introduction. Automated identification of arthroplasty implants could aid in pre-operative planning and is a task which could be facilitated through artificial intelligence (AI) and deep learning. The purpose of this study was to develop and test the performance of a deep learning system (DLS) for automated identification and classification of knee arthroplasty (KA) on radiographs. Methods. We collected 237 AP knee radiographs with equal proportions of native knees, total KA (TKA), and unicompartmental KA (UKA), as well as 274 radiographs with equal proportions of Smith & Nephew Journey and Zimmer NexGen TKAs. Data augmentation was used to increase the number of images available for DLS development. These images were used to train, validate, and test deep convolutional neural networks (DCNN) to 1) detect the presence of TKA; 2) differentiate between TKA and UKA; and 3) differentiate between the 2 TKA models. Receiver operating characteristic (ROC) curves were generated with area under the curve (AUC) calculated to assess test performance. Results. The DCNNs trained to detect KA and to distinguish between TKA and UKA both achieved AUC of 1. In both cases, heatmap analysis demonstrated appropriate emphasis of the KA components in decision-making. The DCNN trained to distinguish between the 2 TKA models also achieved AUC of 1. Heatmap analysis of this DCNN showed emphasis of specific unique features of the TKA model designs for decision making, such as the anterior flange shape of the Zimmer NexGen TKA (Figure 1) and the tibial baseplate/stem shape of the Smith & Nephew Journey TKA (Figure 2). Conclusion. DCNNs can accurately identify presence of TKA and distinguish between specific designs. The proof-of-concept of these DCNNs may set the foundation for DCNNs to identify other prosthesis models and prosthesis-related complications. For any figures or tables, please contact the authors directly

The age spectrum for patients undergoing shoulder arthroplasty is broadening. Many younger patients now demonstrate shoulder pathology precluding non-arthroplasty reconstruction. The senior population is living longer and “younger”. Therefore, the demands of this patient population to participate in an active lifestyle are growing. Patients with osteoarthritis, cuff tear arthropathy, post-traumatic arthropathy, avascular necrosis, and even forms of inflammatory arthropathy present seeking not only return to simple activities of daily living but the ability to participate in aerobic recreational activities and even work activities which can stretch the limits of shoulder arthroplasty in the physiologic environment of the shoulder. This presentation will provide an overview of patient demands, concerns and activity level following shoulder arthroplasty. We will provide a prospective of allowable, recommended and discouraged activities depending on the underlying source of pathology in the type of arthroplasty implants employed. An overview of our four phases of rehabilitation protocol will be presented focusing on phase four, “work in sports hardening”

The Failed Femoral Neck Fracture. For the young patient: Attempt to preserve patient's own femoral head. Clinical results reasonably good even if there are patches of avascular necrosis. Preferred methods of salvage: valgus-producing intertrochanteric femoral osteotomy: puts the nonunion under compression. Other treatment option: Meyer's vascularised pedicle graft. For the older patient: Most reliable treatment is prosthetic replacement. Decision to use hemiarthroplasty (such as bipolar) or THA based on quality of articular cartilage, perceived risk of instability problem. In most patients THA provides higher likelihood of excellent pain relief. Specific technical issues: (1) hardware removal: usually remove after hip has first been dislocated (to reduce risk of femur fracture); (2) Hip stability: consider methods to reduce dislocation risk: larger diameter heads/dual mobility/anteriorly-based approaches; (3) Acetabular bone quality: poor because it is not sclerotic from previous arthritis; caution when impacting a pressfit cup; low threshold to augment fixation with screws; don't overdo reaming; just expose the bleeding subchondral bone. A reasonable alternative is a cemented cup. The Failed Intertrochanteric Hip Fracture. For the young patient: Attempt to salvage hip joint with nonunion takedown, autogenous bone grafting and internal fixation. For the older patient: Decision to preserve patient's own hip with internal fixation versus salvage with hip arthroplasty should be individualised based on patient circumstances, fracture pattern, bone quality. THA is an effective salvage procedure for this problem in older patients. If prosthetic replacement is chosen special considerations include:. THA vs. hemiarthroplasty: hemiarthroplasty better stability; THA more reliable pain relief. Removal of hardware: be prepared to remove broken screws in intramedullary canal. Management of bone loss: bone loss to level of lesser trochanter common. Often requires a calcar replacement implant. Proximal calcar build-up size dictated by bone loss. Length of stem: desirable to bypass screw holes from previous fixation, if possible. Stem fixation: cemented or uncemented fixation depending on surgeon preference, bone quality. If uncemented, consider diaphyseal fixation. Greater trochanter: often a separate piece, be prepared to fix with wires or cable grip. Residual trochanteric healing, hardware problems not rare after THA

Demographic changes will increase the number of surgical procedures in the next years. Therefore, quality assurance of clinical processes, such as the reprocessing of surgical instruments as well as intraoperative workflows will be of increasing importance to ensure patient safety. Surgical procedures are often complex and may involve risks for the patient. For fixation of screws, e.g. in case of pedicle screws, osteosynthesis plates or revision joint replacement surgery implants, the application of defined torques may be crucial in order to achieve optimal therapeutic results and minimal complication rates. In many cases a subjective rating of the surgeon is necessary as no adequate instrumentation is available. With the same subjective feeling, hammering or screwing in are performed to implant e.g. the acetabular component in THA. Our actual work is dedicated to the implementation of a functional prototypes of sensor- integrated instruments for specific types of intervention (especially in traumatology) and the evaluation of the sensor integrated surgical instruments in combination with RFID technology for smart process optimisation in the operating room as well as for reprocessing of surgical instruments and surgical management in combination with a knowledge-based planning, control and documentation system. Complementary (preferably wireless) sensors such for instrument identification, tracking or more complex measurements such as forces, torques, temperature or impacts during surgery as well as during reprocessing of reusable instruments could enable computer network based quality assurance in a much broader and comprehensive manner. Within the framework of the OR.NET initiative we follow the approach to integrate wireless sensors for measurement of temperature, force-torque as well as inertial sensors for orientation and impact control, depending on the specific type of application for monitoring of workflows during surgery as well as during reprocessing of reusable instruments and devices. The integration of smart surgical instruments into an open networked operating room based on the open communication standard IEEE 11073 knowledge-based workflow system, can help to improve the process and quality management

Arthroplasty implant modularity enables the surgeon to adapt the joint replacement construct to the patient's requirements, and often facilitates revision procedures. Total shoulder arthroplasty humeral modularity exists for many implant systems. Glenoid modularity with convertibility between anatomic and reverse shoulder arthroplasty is a recent development. Glenoid modularity is very useful when reconstructing glenoid bone deficiencies, or in providing a method for reverse shoulder arthroplasty joint lateralization. The live surgery will demonstrate a bio-reverse total shoulder arthroplasty (bRTSA). The humeral component is a modular press fit stem that can accommodate either reverse or anatomic metaphyseal components. The metaphyseal components can be exchanged without removing the stem or changing the humeral height. The glenoid base has three components. The trabecular titanium peg is available in two diameters, and four lengths for each diameter. The peg is fixed to a metal base plate via Morse taper. In revision settings, these components can be easily dissociated in situ, and a coring drill inserted over a well-fixed peg allows removal with minimal bone loss. Either a polyethylene component, or glenosphere can be attached to the baseplate to complete the glenoid construct. An innovative set of instruments have been developed to reliably prepare the glenoid and humeral bone graft. While the live surgery will demonstrate the grafting technique in a bRTSA, it can also be used to reconstruct glenoid deficiencies (eg, Walch B2). Implants have been developed to solve these issues, but often do so at the expense of very limited glenoid bone stock. Bone grafting actually creates a net increase in glenoid bone stock that may improve implant durability, and decrease revision complexity. The technique is quite simple and adds approximately ten minutes to operative time. I have used this technique for 5 years with no cases of graft failure

Background. Periprosthetic joint infection (PJI) is a devastating complication and interest exists in finding lower cost alternatives to current management strategies. Current strategies include a two-stage revision with placement of an antibiotic spacer and delayed placement of a new arthroplasty implant. This study aimed to show that biofilm residue can be reliably eradicated on infected implants, safely allowing re-implantation in a spacer. Methods. Strains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on cobalt-chrome discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication; (3) autoclave + saline scrub; (4) autoclave + 4% chlorhexidine (CHC) scrub; and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy (SEM). Results. Relative to non-treated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. On average, the most effective sterilization and biofilm removal treatment was the combined treatment of autoclaving, sonication and CHC-scrub for MRSA252 (100%) and RP62A (99.8%). High resolution SEM revealed no cells or biofilm for this combined treatment. Conclusions. Using two commonly encountered bacterial strains in PJI, infected cobalt-chrome implants were sterilized and eradicated of residual biofilm with a combination of autoclaving, sonication and CHC scrubbing. This protocol is time efficient, can be done in the OR and provides a basis for reuse of infected implants as articulating spacers in PJI

Introduction. Self tapping bone screw has been widely used in the fixation of Arthroplasty implants and bone graft. But the unwanted screw or driver breakage can be a direct result of excessive driving torque due to the thread cutting resistance. Previous studies showed that bone drill bit cutting rake angle was a critical factor and was inversely related to the bone cutting efficiency. 1, 2, 3, 4. (Figure 1) However to date there was no data for how the rake angle could influence the performance of self tapping bone screw. The purpose of this study was to investigate the torque generated by the self tapping cortical screw in simulated bone insertion as a function of the screw tip cutting flute rake angle. Methods. Two 5 mm thick BM5166 polyurethane block were stacked together and drilled through with 2.5mm diameter holes. Five 30mm long 3.5 mm diameter Ti6AL4V alloy self tapping cortical screws with 0°rake angle cutting flutes (Figure 2) were inserted in the holes and driven by the spanner attached to the test machine (Z5.0TN/TC-A-10) with a displacement control of 3 revolutions/min and 30N constant axial loading. The screws were driven into the stacked polyurethane block for 8mm depth. The maximum driving torque was recorded. Procedure was repeated for five same screws but with 7° rake angle cutting flutes. (Figure 2) The driving torqueses were compared. Student t test was performed with confidence level of 95% was assumed. Results. The average insertion driving torque for the screw with 7° rake angle was 30% less torque required than that of the screw with 0° rake angle. (P=5.3E–06<0.05) (Table 1). Conclusion and discussion. Screw failure during the insertion would be a nightmare. A slight positive rake angle significantly decreases the torque resistance. This design feature can significantly increase the safety margin of the self tapping screw implants and screw driving instruments. The likely mechanism would be the positive rake angle generated a more efficient bone cutting instead of pushing. More study on driving torque as a function of wider rake angle change is warranted. For figures and tables, please contact authors directly

Titanium (Ti) alloy is the material of choice for the porous bone ingrowth materials for non-cemented total Joint arthroplasty. Recent studies have shown the importance of controlling the macro, micro, and nano surface topographies on the bone apposition surfaces of these implants. Historically, much attention has been given to the designs of macro fixation features (millimeter scale), and the design of micro fixation porosity (micrometer scale). More recently, the importance of the nano-surface texture (nanometer scale) is being recognised as an integral component of the design. Nano-textures are being enhanced during implant processes to optimise the bond between implant and bone. The ultra-hydrophilic nano-texture of an implant interacts with the corresponding nano-texture of the outer cell membranes to increase cell adhesion and differentiation. This speeds the osseointegration rate between Ti alloys, and the surrounding osteoblast tissues. Living cells sense and respond to surface texturing on the nanoscale which in turn direct stem cell and osteoblast differentiation. This has been recognised to improve the speed at which the implant interface bonds to bone with the end goal of ultimately allowing patients to weight bear on non-cemented arthroplasty implants sooner. One surface modification treatment technique of particular promise is nano-texturing via. electrochemical anodization to form arrays of vertically aligned, laterally spaced titanium dioxide (TiO2) nanotubes on titanium implant surfaces in areas where enhanced implant-to-bone fixation is desired. Bio-mimicking TiO2 nanotube arrays are superimposed onto existing porous surface micro-structures to further enhance the already known bone ingrowth properties of these porous structures. These nanotube arrays show an accelerated osseointegration. Foundational work has demonstrated that the TiO2 nanotube surface architecture significantly accelerates osteoblast cell growth, improves bone-forming functionality, and even directs mesenchymal stem cell fate. Current generation nano-surface modification technologies show improved osseointegration response between implant materials and surrounding tissue and also provide surfaces that resist microbial adhesion. Implant surfaces treated with and without TiO2 nanotubes were compared to grit blasted Ti controls in-vitro and in-vivo. The samples we evaluated after exposure to human mesenchymal stem cell (hMSC). Additionally, implants have been evaluated in multiple animal models with and without TiO2 nanotubes. The bones with implants were retrieved for mechanical testing and histology analysis. The average bond strength was significantly higher (150% to 600%, depending on the in-vivo animal model) for TiO2 nanotube implants compared to the non-treated Ti control implants. The histology confirms direct bonded growth of new bone onto the nanotubes with a significantly less trapped amorphous tissue at the implant-bone interface compared to the controls. Both in-vitro and in-vivo analysis indicates that TiO2 nano-texturing enhances the speed and proliferation of osseointegration. This surface treatment technique can be applied to non-porous or porous surfaces on TJA implants where improved bone fixation is desired

Introduction. Titanium (Ti) alloys are used as porous bone ingrowth materials on non-cemented knee arthroplasty tibial tray implants. Nano-surface mechanism that increase the osseointegration rate between Ti alloys, and surrounding tissue has been recognized to improve the interface to ultimately allow patients to weight bear on non-cemented arthroplasty implants sooner. Bioactive TiO. 2. nanotube arrays has been shown to accelerate osseointegration. Ideally, these surfaces would both increase the adhesion of bone to the implant and help to reduction of infection to substitute for antibiotic bone cement. This study examines a combination treatment of both TiO. 2. nanotubes combined with silver nano-deposition, that simultaneously enhances osseointegration while improving infection resistance, by testing ex vivo implantation stability in an equine cadaver bone followed by in vitro and in vivo analysis to understand the biocompatibility and early stage osseointegration. Methods. 100nm diameter and 300nm length TiO. 2. nanotubes were formed on a CP titanium surface using anodization method at 20V for 45mins using 1% HF electrolyte. Silver deposition on TiO. 2. nanotubes were performed using 0.1M AgNO. 3. solution at 3V for 45s. Figure 1 shows SEM images showing (a) TiO. 2. nanotubes of 300nm length and (b) nanotubes with silver coating). Ti anodized samples with and without silver nanotubes implanted into an equine cadaver bone in an ex vivo manner to study the stability of nanotubes and the adherence of silver deposition. Silver release study was performed for a period of 14 days in a similar ex vivo manner. Dimensions for implantation samples: 2.5 mm diam. × 15 mm. For cell culture, circular disc samples 12.5mm in diameter and 3 mm in thickness were used to study the bone cell-material interactions using human fetal osteoblast (hFOB) cells. To evaluate the cell proliferation, MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay was used. The in vitro cell-materials interaction study was performed for a period of 4 and 7 days. In vivo study was performed using rat distal femur model for a period of 12 weeks with dense Ti samples as control (Sample dimensions: 3mm diam. × 5mm). At the end of 12 weeks, the samples were analyzed for early stage osseointegration using histological analysis and SEM imaging. Results. No significant changes in the morphology of nanotubes was observed due to the implantation process which signifies the damage resistance these nanotubes can endure during implantation and explantation. Figure 2 shows SEM images of (a) & (b) nanotubes without silver coating before and after implantation and (c) & (d) nanotubes with silver coating before and after implantation respectively. Silver nanocoatings can be observed after implantation which shows the adherence of the antimicrobial nano-coating on the surface of nanotubes. Cumulative release profiles of silver ions after 14 days showed the total release was in the effective range for antimicrobial characteristics and was well below the toxic limit specified for human cells (10 ppm) Figure 3(a) shows cumulative release profile of silver after 14 days. MTT assay and SEM images show good cell proliferation, antimicrobial effect, and increase in cell density after 7 days for samples with nanotubes and silver with no cytotoxic effects and good cell attachment on the samples as shown in Figure 3(b) MTT assay results showing cell densities after 4 and 7 days and Figure 3(c) SEM images showing cell attachment after 4 and 7 days on samples. Histological analysis and SEM images showed osteoid formation around the implant with improved bonding towards the implant and bone showing signs of early stage osseointegration. Figure 4 shows histological and SEM images showing bonding between bone and implant surface for respective samples after 12 weeks. Conclusions. Mechanically stableTiO. 2. nanotubes with strongly adhered antimicrobial silver coating were grown on the surface of titanium which were biocompatible and non-toxic. In vitro and in vivo tests indicate improved cell-materials interaction with signs of early stage osseointegration. This nano-surface treatment shows promise towards simultaneously improving early stage osseointegration and providing an infection barrier on bone ingrowth materials

Introduction. There is a demand for longer lasting arthroplasty implants driving the investigation of novel material combinations. PEEK has shown promise as an arthroplasty bearing material, with potentially relatively bio inert wear debris [1]. When coupled with an all-polyethylene tibial component this combination shows potential as a metal-free knee. In this study, the suitability of PEEK Optima® as an alternative to cobalt chrome for the femoral component of total knee replacements was assessed using experimental knee wear simulation under two kinematic conditions. Methods. Three cobalt chrome and three injection moulded PEEK Optima® (Invibio Biomaterial Solutions, UK) femoral components of similar geometry and surface roughness (mean surface roughness (Ra) ∼0.02µm) were coupled with all-polyethylene GUR1020 (conventional, unsterilised) tibial components in a 6 station ProSim knee simulator (Simulation Solutions, UK). 3 million cycles (MC) of wear simulation were carried out under intermediate kinematics (maximum anterior-posterior (AP) displacement 5mm) followed by 3MC under high kinematics (AP 10mm) [2] with 25% serum as the lubricant. The wear of the tibial component was assessed gravimetrically. At each measurement point, the surface roughness of the femoral components was determined using contacting profilometry and throughout testing, the bulk lubricant temperature was monitored close to the articulating surfaces. Statistical analysis was carried out using ANOVA, with significance at p<0.05. Results. Figure 1 shows the wear rate of the all-polyethylene tibial components. After 3MC of intermediate kinematics, the mean wear rate of UHMWPE articulating against cobalt chrome was 1.0±2.3mm3/MC and against PEEK was similar (p=0.06) 2.5±0.8mm3/MC. Scratches were apparent on the surface of the PEEK implant in the AP direction significantly (p<0.05) increasing mean surface roughness of the PEEK components (Table 1) compared to pre-test values. The surface topography of the cobalt chrome components (Table 2) was similar to pre-test measurements. Increasing AP displacement caused no significant increase in the wear of the tibial inserts against either material. Under intermediate kinematics, the mean bulk lubricant temperature was 28.0±0.7°C for cobalt chrome and significantly higher (p<0.001) for PEEK, 29.5±0.1°C; kinematic conditions had no effect on the lubricant temperature. Conclusions. This study showed a similar wear rate of all-polyethylene tibial components against PEEK and cobalt chrome femoral components of similar initial surface topography and geometry. Wear simulation with a higher AP displacement did not increase the wear of the polyethylene, in contrast to other designs of knee replacements, potentially due to the low conforming geometry of the implant [3]. The linear scratching on the surface of the PEEK implants did not increase the wear rate of the tibial components and the surface did not deteriorate further between 3 and 6 MC. A higher mean lubricant temperature was measured with PEEK femoral components, which was attributed to the higher friction of the PEEK-PE bearing couple. However it is not known whether this is clinically relevant or an artefact of the continuous running of the simulator. PEEK Optima® shows promise as the femoral component in a metal-free knee

Background. Both surgeon and hospital volume influence patient outcomes following revision knee arthroplasty. Purpose. To audit all centres performing revision knee procedures in England and Wales over a 2-year period. All centres were audited against two pre-defined standards linked to hospital volume. Operative volume should be greater than 10 revisions per year;. More than 2.5 revisions should be performed for every 100 primary arthroplasties implanted. Methods. Data for 9659 knee revisions performed in 359 different centres between 01/07/08 and 30/06/10 was accessed from the National Joint Registry for England and Wales. For each centre information on the volume of primary and revision knee procedures undertaken during this period was available and was used as the basis for audit. Results. During the 2-year study period 396 different centres performed 153133 primary knee arthroplasties. Of these 359 (91%) performed 9659 knee revisions, equivalent to 6.2 revisions for every 100 primary arthroplasties performed. Revision centres included 208 (58%) NHS hospitals performing 8148 revisions, 141 (39%) independent hospitals performing 1258 revisions and 10 (3%) Independent Sector Treatment Centres (ISTC) performing 253 revisions. The median number of revisions performed per hospital was 7 per year (Range 1 to 144). Volume differed dependent upon hospital type (NHS=14/year vs. Independent=3/year, p< 0.001). Two hundred and twelve (59%) centres performed < 10 revisions per year and thus fell below the audit standard. Eighty of these centres also performed < 2.5 revisions per 100 primaries. Of the 141 independent hospitals 128 (91%) fell below the suggested standards for revision volume. Conclusions. A significant number of institutions are performing only a small volume of knee revision procedures. To ensure safe and sustainable practice with better outcomes, consideration should be given to rationalising the revision service in fewer centres

Oxide ceramics, such as alumina and zirconia have been used extensively in arthroplasty bearings to address bearing wear and mitigate its delayed, undesirable consequences. In contrast to oxide ceramics that are well-known to orthopaedic surgeons, silicon nitride (Si. 3. N. 4. ) is a non-oxide ceramic that has been investigated extensively in very demanding industrial applications, such as precision bearings, cutting tools, turbo-machinery, and electronics. For the past four years, Si. 3. N. 4. has also been used as a biomaterial in the human body; specifically in spinal fusion surgery. As a implantable biomaterial, Si. 3. N. 4. has unique properties, such as high strength and fracture toughness, inherent chemical and phase stability, low wear, proven biocompatibility, excellent radiographic imaging, antibacterial advantages, and superior osteointegration. This property combination has proven beneficial and desirable in orthopaedic implants made for spinal fusion, spinal disc reconstruction, hip and knee arthroplasty, and other total joints (Fig. 1). The physical properties, shapes, sizes and surface features of Si. 3. N. 4. can be engineered for each application – ranging from dense, finely polished articulation components, to highly porous scaffolds that promote osteointegration. Both porous and polished surfaces can be incorporated in the same implant, opening a number of opportunities for arthroplasty implant design. Crack propagation modes for in situ toughened Si. 3. N. 4. differ favorably from those of conventional ceramics, rendering Si. 3. N. 4. extremely resistant to catastrophic failure in vivo (Fig. 2). Most significantly, our recent work has shown that Si. 3. N. 4. is resistant to bacterial biofilm formation, colonization and growth, when compared to medical-grade PEEK and titanium. These anti-infective characteristics are particularly valuable for in vivo implantation. We will present the unique properties and characteristics of Si. 3. N. 4. , and compare these to other ceramic and non-ceramic biomaterials. Si. 3. N. 4. was once used only in industrial applications, but early data show that this novel biomaterial is positively impacting orthopaedic care and will continue to do so into the future

Purpose. There has been recent interest in gender-specific arthroplasty implant design but little evidence to support their use. We hypothesised that outcomes among arthroplasty patients are affected by gender. Methods. Patients were retrospectively identified from a prospective database of TJRs performed at one centre among six surgeons over a ten-year period (1998-2008). Demographics, pre-operative and 1-year clinical Knee Society (KSS), Harris Hip (HHS), and Oxford scores were collected. Gender differences were analysed using independent samples t-test and chi-square. Results. The study sample was comprised of 4780 primary unilateral TJRs performed for osteoarthritis, including 3186 cemented TKAs (63% females, 37% males), and 1594 cementless THAs (55% females, and 45% males). Among TKAs, females had higher BMIs, and differing rates of comorbidities and complications. Female KSS, Oxford and flexion scores were significantly inferior to male scores pre-operatively and at 1-year follow-up. Significantly more females reported higher pain scores and inferior stair climbing ability compared to males at all intervals. Females showed significantly more improvement in clinical outcomes, including flexion from pre-operative to one-year. Among THAs, females were significantly younger with higher BMIs. There were varying rates of complications and comorbidities by gender. Females had significantly worse HHS and Oxford scores, and inferior stair climbing ability at all intervals. Pain scores were higher for females pre-operatively and at 6 weeks, but became equivalent thereafter. Females showed significantly greater outcomes improvement pre-operative to one-year. Conclusion. As reported in the literature, results of this study indicate that women choose arthroplasty at a later stage of disease, presenting with inferior functional status. The effect of waiting seems most marked among the TKA population with inferior outcomes and pain relief persisting to one year. Although women do have inferior outcomes, their overall level of improvement is superior. Surgeons must counsel females differently about expectations and TJR recovery

Objective. Superior bone ingrowth and resistance to bacterial infection are ideal for orthopaedic implants. We compared new bone formation, strength of bone bonding, and infection rates between silicon nitride ceramic (Si3N4; abbreviated SiN), medical-grade PEEK (PEEK), and titanium (Ti) in rat calvariae. PEEK and Ti are used in spinal and arthroplasty implants respectively, while SiN is a non-oxide ceramic used in spinal implants for the past 4 years. Methods. Specimens of 10 mm × 10 mm by 1.75 mm size were implanted into experimental calvarial defects in 2-year old Wistar rats using standard surgical techniques (n's: SiN=48; PEEK=24; Ti=24). One group of animals was immediately inoculated with 1 × 104 Staphylococcus epidermidis; control animals received saline only. After sacrifice at 3 days, 7 days, 14 days, and 3 months post-inoculation (n=4 rats per time period), one calvarial sample each for PEEK and Ti, and two samples for SiN (per bacterial condition and time point) were retrieved for histology; remaining samples were used for sample push-out testing with a Micro Tester 5848 (Instron) with a 1-kN load cell, using published techniques. New bone formation was measured with tetracycline double-labeling at 11 and 4 days before the 14-day and 3-month time periods. Results. Of the materials tested, 3-month bone ingrowth and periprosthetic infection rates were most favorable for SiN (Fig. 1). At 90 days post-implantation without bacteria, new bone growth in calvariae with SiN was ∼69% compared with 24% and 36% for PEEK and Ti, respectively. With bacterial inoculation, new bone growth was 21%, 26% and 41% for PEEK, Ti, and SiN, respectively. At 3-months, live bacteria were observed for PEEK (88%) and Ti (21%), while no bacteria were present around SiN (Fig. 2). Push-out strength was greater for SiN when compared to Ti and PEEK (Fig. 3). Conclusions. Superior bone formation, bone ingrowth, and bacterial resistance were associated with SiN when compared to Ti and PEEK. SiN proved effective in inhibiting bacteria and promoting osteogenesis in experimental osseous defects, when compared to Ti and PEEK. These observations are most likely related to the hydrophilic properties of SiN that contributed to the adsorption of proteins known to decrease bacteria attachment and growth (vitronectin and fibronectin). We conclude that SiN may be a superior biomaterial for the development of orthopaedic implants

There are many types of arthroplasties for the 1st MTPJ, but still the treatment of advance Hallux rigidus remains controversial. In this study we are reporting the outcome of the North Star hemicap at 6 months. A series of patients under the care of a single surgeon were followed using the Manchester - Oxford Foot Questionnaire (MOXFQ) at 6months post operation, and a satisfaction question was asked. The operations were between August 2011 and August 2013. A total of forty five arthroplasties were implanted in 44 patients. Thirty four of them were female and 9 were male. The average age was 56 years (range 37–77 years). Twenty six out of them (59%) needed an MUA + a local anaesthetic and steroid injection of the prosthetic joint at 2 to 14 months (average 6 months) post implantation. In these patients the MOXFQ was filled at 6months post the MUA and injection. Four of them were left out of the study because they were less than 6months post MUA. One patient had his implant removed and changed to fusion at his request at 14 months post implantation. Forty one patients were satisfied and would recommend the operation, 2 were disappointed with the degree of movement but would still recommend the operation and one had it revised to fusion. The average MOXFQ was 12/64. In conclusion, high percentage of patients needed a second operation, but the scores are reasonably low and almost all patients would recommend it. Further follow up of these patients is needed for at least 5years but the early results are showing it to be a good alternative for fusion