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

We present the indications and outcomes of a series of custom 3D printed titanium acetabular implants used over a 9 year period at our institution (Sydney, Australia), in the setting of revision total hip arthroplasty. Individualised image-based case planning with additive manufacturing of pelvic components was combined with screw fixation and off-the-shelf femoral components to treat patients presenting with failed hip arthroplasty involving acetabular bone loss. Retrospective chart review was performed on the practices of three contributing surgeons, with an initial search by item number of the Medicare Benefits Scheme linked to a case list maintained by the manufacturer. An analysis of indications, patient demographics and clinical outcome was performed. The cohort comprised 65.2% female with a median age of 70 years (interquartile range 61–77) and a median follow up of 32.9 months (IQR 13.1 - 49.7). The indications for surgery were infection (12.5%); aseptic loosening (78.1%) and fracture (9.4%), with 65.7% of cases undergoing previous revision hip arthroplasty. A tumour prosthesis was implanted into the proximal femur in 21.9% of cases. Complications were observed in 31.3% of cases, with four cases requiring revision procedures and no deaths reported in this series. Kaplan-Meier analysis of all-cause revision revealed an overall procedure survival of 88.7% at two years (95%confidence interval 69 - 96.2) and 83.8% (95%CI 62 - 93.7) at five years, with pelvic implant-specific survival of 98% (95%CI 86.6 - 99.7) at two and five year follow up. We conclude that an individualised planning approach for custom 3D printed titanium acetabular implants can provide high overall and implant-specific survival at up to five years follow up in complex cases of failed hip arthroplasty and acetabular bone loss

Aim. Orthopedic implants play a tremendous role in fixing bone damages due to aging as well as fractures. However, these implants tend to get colonized by bacteria on the surface, leading to infections and subsequently prevention of healing and osteointegration. Recently, Roupie et al. showed that a nisin layer-by-layer based coating applied on biomaterials has both osteogenic and antibacterial properties. The Galleria mellonella larva is a well-known insect infection model that has been used to test the virulence of bacterial and fungal strains as well as for the high throughput screening of antimicrobial compounds against infections. Recently, we have developed an insect infection model with G. mellonella larvae to study implant-associated biofilm infections using Kirschner (K)-wires as implant material. Here, we would like to test the antibacterial capacity of nisin layer-by-layer based coatings on K-wires against Staphylococcus aureus in the G. mellonella larva implant infection model. Method. Prior to the implantation procedure, G. mellonella larvae are maintained at room temperature on wheat germ in an incubator. The larvae received bare titanium K-wires (uncoated), or either control-coated or nisin-coated K-wires. After one hour, the larvae were injected with 5×10. 5. S. aureus bacteria per larva (i.e., hematogenous implant infection model). Next, the larvae were incubated at 37. o. C in an incubator and the survival of the larvae was monitored for five days. Moreover, the number of bacteria on the implant surface and in the surrounding tissue was determined after 24h of incubation. Further, scanning electron microscopy (SEM) analyses were performed to study the effect of nisin on biofilm formation. Results. The larvae receiving the nisin-coated K-wires showed significantly higher survival rates compared to uncoated titanium K-wires, although not when compared to control-coated K-wires. A more than 1-log reduction in number of bacteria on the implant surface and in the surrounding tissue was observed in larvae receiving the nisin-coated K-wires, when compared to uncoated titanium K-wires SEM analysis showed reduced colonization of the bacteria nisin-coated K-wires compared to the controls. Conclusions. In conclusion, the antimicrobial nisin layer-by-layer based coating applied on titanium surfaces is able to prevent implant-related S. aureus biofilm infection in G. mellonella and is a promising antimicrobial strategy to prevent implant-related infections

Polyetheretherketone (PEEK) interbody fusion cages combined with autologous bone graft is the current clinical gold standard treatment for spinal fusion, however, bone graft harvest increases surgical time, risk of infection and chronic pain. We describe novel low-stiffness 3D Printed titanium interbody cages without autologous bone graft and assessed their biological performance in a pre-clinical in vivo interbody fusion model in comparison to the gold standard, PEEK with graft. Titanium interbody spacers were 3D Printed with a microporous (Ti1: <1000μm) and macroporous (Ti2: >1000μm) design. Both Ti1 and Ti2 had an identical elastic modulus (stiffness), and were similar to the elastic modulus of PEEK. Interbody fusion was performed on L2-L3 and L4-L5 vertebral levels in 24 skeletally mature sheep using Ti1 or Ti2 spacers, or a PEEK spacer filled with iliac crest autograft, and assessed at 8 and 16 weeks. We quantitatively assessed bone fusion, bone area, mineral apposition rate and bone formation rate. Functional spinal units were biomechanically tested to analyse range of motion, neutral zone, and stiffness. Results: Bone formation in macroporous Ti2 was significantly greater than microporous Ti1 treatments (p=.006). Fusion scores for Ti2 and PEEK demonstrated greater rates of bone formation from 8 to 16 weeks, with bridging rates of 100% for Ti2 at 16 weeks compared to just 88% for PEEK and 50% for Ti1. Biomechanical outcomes significantly improved at 16 versus 8 weeks, with no significant differences between Ti and PEEK with graft. This study demonstrated that macroporous 3D Printed Ti spacers are able to achieve fixation and arthrodesis with complete bone fusion by 16 weeks without the need for bone graft. These significant data indicate that low-modulus 3D Printed titanium interbody cages have similar performance to autograft-filled PEEK, and could be reliably used in spinal fusion avoiding the complications of bone graft harvesting

Aims. Only a small number of studies exist that report the results of EBM-produced porous coated trabecular titanium cups in primary total hip arthroplasty (THA). This study aims to investigate the patient satisfaction level, clinical function and radiographic outcomes of the patients who underwent THA using an EBM-produced porous coated titanium cup. Patients and Methods. A total of 32 patients who underwent primary THA with using an EBM-produced porous coated titanium cup from five hospitals between May and December, 2012 were retrospectively reviewed. Five patients were lost prior to the minimum 6-year follow-up. Clinical and radiographic outcomes were analyzed with an average follow-up of 81.48 (range: 77.00–87.00) months. Results. The median HHS and SF-36 scores improved significantly while the WOMAC Osteoarthritis Index decreased significantly at the latest follow-up (p<0.001). Eighteen (66.7%) patients rated their satisfaction level as very satisfied, 6 (22.2%) as satisfied, 2 (7.4%) as neutral and 1(3.7%) as dissatisfied. No intraoperative or postoperative complications were identified, including aseptic cup loosening, hip dislocation, periprosthetic joint infection, periprosthetic fracture, nerve palsy, hematoma. At the latest follow-up, all cups were considered to have achieved fixation via bone ingrowth with three or more of the five signs occurring in the most recent X-ray. However, three cups revealed radiolucent lines with a width of less than 1 mm. These radiolucent lines were distributed in the DeLee-Charnley zone 1 in 1 patient, zone 3 in another patient and the area between zone1 and zone 2 in an additional patient. The latest postoperative centers of rotation were restored nearly to the anatomic center of rotation both vertically and horizontally and the acetabular cups obtained satisfactory orientation postoperatively. Conclusions. The mid-term follow-up of patients who underwent primary THA using EBM-produced porous coated titanium cups demonstrated favorable patient satisfaction, clinical function and adequate biological fixation. For any figures or tables, please contact authors directly

Introduction: The mechanobiology and response of bone formation to strain under physiological loading is well established, however investigation into exceedingly soft scaffolds relative to cancellous bone is limited. In this study we designed and 3D printed mechanically-optimised low-stiffness implants, targeting specific strain ranges inducing bone formation and assessed their biological performance in a pre-clinical in vivo load-bearing tibial tuberosity advancement (TTA) model. The TTA model provides an attractive pre-clinical framework to investigate implant osseointegration within an uneven loading environment due to the dominating patellar tendon force. A knee finite element model from ovine CT data was developed to determine physiological target strains from simulated TTA surgery. We 3D printed low-stiffness Ti wedge osteotomy implants with homogeneous stiffness of 0.8 GPa (Ti1), 0.6 GPa (Ti2) and a locally-optimised design with a 0.3 GPa cortex and soft 0.1 GPa core (Ti3), for implantation in a 12-week ovine tibial advancement osteotomy (9mm). We quantitatively assessed bone fusion, bone area, mineral apposition rate and bone formation rate. Optimised Ti3 implants exhibited evenly high strains throughout, despite uneven wedge osteotomy loading. We demonstrated that higher strains above 3.75%, led to greater bone formation. Histomorphometry showed uniform bone ingrowthin optimised Ti3 compared to homogeneous designs (Ti1 and Ti2), and greater bone-implant contact. The greatest bone formation scores were seen in Ti3, followed by Ti2 and Ti1. Results from our study indicate lower stiffness and higher strain ranges than normally achieved in Ti scaffolds stimulate early bone formation. By accounting for loading environments through rational design, implants can be optimised to improve uniform osseointegration. Design and 3D printing of exceedingly soft titanium orthopaedic implants enhance strain induced bone formation and have significant importance in future implant design for knee, hip arthroplasty and treatment of large load-bearing bone defects

Periprosthetic infection remains a clinical challenge that may lead to revision surgeries, increased spending, disability, and mortality. The cost for treating hip and knee total joint infections is anticipated to be $1.62 billion by 2020. There is a need for implant surface modifications that simultaneously resist bacterial biofilm formation and adhesion, while promoting periprosthetic bone formation and osseointegration. In vitro research has shown that nanotextured titanium promotes osteoblast differentiation, and upregulates metabolic markers of osteoblast activity and osteoblast proliferation. In vivo rat studies confirmed increased bone-implant contact area, enhanced de novo bone formation on and adjacent to the implant, and higher pull-out forces compared to non-textured titanium. The authors have advanced a benign electrochemical anodization process based on ammonium fluoride that creates a nanotube surface in as little as 10 minutes (Fig. 1), which can also integrate antibacterial nanosilver (Fig. 2). The work reported here summarizes in vitro post-inoculation and in vivo post-implantation studies, showing inherent inhibition of methicillin-resistant Staphylococcus aureus (MRSA) by titanium surfaces with nanotubes (TiNT), nanotubes with nanosilver (TiNT+Ag), plain (Ti), and thermal plasma sprayed (TPS) titanium. Ti6Al4V was the base material for all surfaces. In vitro studies evaluated Ti, TPS, four TiNT groups with varying nanotube diameters (60nm, 80nm, 110nm, 150nm), and TiNT+Ag. After seeding with MRSA (10. 5. , 10. 6. , and 10. 8. CFU/mL), the 110nm diameter nanotubes showed MRSA inhibition up to three-orders of magnitude lower than the Ti and TPS surfaces at 2, 6, and 48 hours. Following on the in vitro results, New Zealand White rabbits underwent a bilateral implantation of intramedullary tibial implants of the four material groups (4 mm outside diameter; 110nm NT diameter on TiNT and TiNT+Ag implants). One intramedullary canal was inoculated with clinically-derived MRSA (10. 5. CFU in broth) at the time of implantation; one canal had only culture media introduced (control). At a 2-week endpoint, limbs were harvested for analysis, including implant sonication with sonicant bacterial cultured, histology, and microcomputed chromatography. In the sonicant analysis cohort, TPS showed the lowest average MRSA count, while TiNT and TiNT+Ag were the highest. There was one sample each of TPS, TiNT and TiNT+Ag that showed no MRSA. After an additional 24-hour implant incubation, the TiNT and TiNT+Ag samples had no bacteria, but the TPS grew bacteria; therefore, the authors hypothesize that MRSA more readily releases from the TiNT and TiNT+Ag implants during sonication, indicating weaker biofilm adhesion and development. Histologic analysis is currently underway. In a therapeutic experiment, rabbits underwent bilateral implantation, followed by 1 week of infection development, and then 1 week of vancomycin treatment. At the endpoint, implants were sonicated and bacteria was quantified from the sonicant. TiNT showed viable MRSA at only 30% that of TPS-coated levels, while TiNT+Ag implants showed viable MRSA at only 5% that of TPS-coated levels (Fig. 3). These early results indicate that the TiNT and TiNT+Ag surfaces have some inherent antibacterial activity against MRSA, which may increase the efficacy of systemic antibiotic treatments in the setting of periprosthetic joint infections

Background. One of the serious postoperative complications associated with joint replacement is bacterial infection. In our recent investigations, iodine supported titanium implants demonstrated antibacterial activity in both in vitro studies and clinical trials. But it is not clear whether iodine treated titanium implants produce strong bonding to bone. This study evaluated the bone bonding ability of titanium implants with and without iodine surface treatments. Methods. Titanium rods were implanted in intramedullary rabbit femur models, in regard to the cementless hip stem. The implant rods were 5mm in diameter and 25mm in length. Half of the implants were treated with iodine (ID implants) and the other half were untreated (CL implants). The rods were inserted into the distal femur; ID implants into the right femur and CL implants into the left. We assessed the bonding strength by a measuring pull-out test at 4, 8, and 12 weeks after implantation. The bone-implant interfaces were evaluated at 4 weeks after implantation. Results. Pull-out test results of the ID implants were 202, 355, and 344 N, at 4, 8, and 12 weeks, respectively, significantly higher than those of the CL implants (102, 216, and 227 N). Histological examination revealed that new bone formed on the surface of both types of implants, but significantly more bone made direct contact with the surfaces of the ID implants. Conclusion. This research showed that new type of coating, iodine coated titanium has low toxicity and good osteoconductivity

Introduction. Cobalt chrome femoral head has been used widely in total hip arthroplasty and has shown favorable outcome. However, there is still of concern of potential metal toxicity from the wear debris. In the other hand, titanium is well known for its biocompatibility but it is not used in bearing surface of arthroplasty due to its brittleness. Recently, coating of the prosthesis using plasma electrolytic oxidation (PEO) has shown favorable surface protection. Thus, in this study, we tried to find out whether the PEO coating on the titanium surface would provide surface protection. Materials and methods. Five Titanium alloy (Ti-6Al-4V) ball mimicking femoral head was manufactured and was coted using plasma electrolytic oxidation. Wear rate was tested using validated wear tester with 10N compression force at 80rpm. The amount of wear was detected by measuring change of weight after wear test was completed. This was compared with femoral head manufactured with titanium alloy without PEO coating. Toxicity of the debris was also tested using MTT assay with human osteoblast cell line. Results. Compare to the base titanium metal, PEO coated metal head has shown to provide surface protection. The wear rate has significantly decreased with PEO coating (median value : 0.00015g/mm. 2. vs 0.00006 g/mm. 2. ). MTT assay revealed no cytotoxicity with the amount of debris generated from the wear test. Conclusion. The result of the current study indicate that the PEO coating on the titanium femoral head can significantly decrease the wear rate and is non cytotoxic. This indicates that the femoral head manufactured with titanium alloy and PEO coating maybe a potential alternative to be used in total hip arthroplasty

During revision total knee arthroplasty (rTKA), proximal tibial bone loss is frequently encountered and can result in a less-stable bone-implant fixation. A 3D printed titanium alloy (Ti6Al4V) revision augment that conforms to the irregular shape of the proximal tibia was recently developed. The purpose of this study was to evaluate the fixation stability of rTKA with this augment in comparison to conventional cemented rTKA. Eleven pairs of thawed fresh-frozen cadaveric tibias (22 tibias) were potted in custom fixtures. Primary total knee arthroplasty (pTKA) surgery was performed on all tibias. Fixation stability testing was conducted using a three-stage eccentric loading protocol. Static eccentric (70% medial/ 30% lateral) loading of 2100 N was applied to the implants before and after subjecting them to 5×103 loading cycles of 700 N at 2 Hz using a joint motion simulator. Bone-implant micromotion was measured using a high-resolution optical system. The pTKA were removed. The proximal tibial bone defect was measured. One tibia from each pair was randomly allocated to the experimental group, and rTKA was performed with a titanium augment printed using selective laser melting. The contralateral side was assigned to the control group (revision with fully cemented stems). The three-stage eccentric loading protocol was used to test the revision TKAs. Independent t-tests were used to compare the micromotion between the two groups. After revision TKA, the mean micromotion was 23.1μm ± 26.2μm in the control group and 12.9μm ± 22.2μm in the experimental group. There was significantly less micromotion in the experimental group (p= 0.04). Prior to revision surgery, the control and experimental group had no significant difference in primary TKA micromotion (p= 0.19) and tibial bone loss (p= 0.37). This study suggests that early fixation stability of revision TKA with the novel 3D printed titanium augment is significantly better then the conventional fully cemented rTKA. The early press-fit fixation of the augment is likely sufficient for promoting bony ingrowth of the augment in vivo. Further studies are needed to investigate the long-term in-vivo fixation of the novel 3D printed augment

Background. Prospective study to compare patient reported outcome measures (PROM) for sacroiliac joint (SIJ) fusion using HA-coated screw (HACS) vs triangular titanium dowel (TTD). First study of its kind in English literature. Methods. 40 patients underwent percutaneous SIJ stabilisation using HACS and TTD was used in 70 patients. Patients were followed up closely and outcome scores were collected prospectively. PROMs were collected preoperatively and 12 months after surgery. Short Form (SF)-36, Oswestry Disability Index, EuroQol-5D-5L and Majeed Pelvic Scores were collected. Shapiro-wilk test was used to determine normality of data. Mann-whitney U test was used to compared non-parametric data and Independent sample T test for parametric data. Results. 33 patients in HACS group and 61 in TTD group completed follow-up. There was no significant difference in all preoperative PROMs in both groups hence the data was considered comparable. All postoperative PROMs were significantly higher in the TTD group. In the HACS group, 21 patients (63%) had lysis around the screw and a sub-group analysis showed that improvement in PROMs was significantly less in patients with lysis around the screw. 4 patients with lysis around the screw were offered revision due to ongoing pain. Revision was successful in only 1 patient. In TTD group only 5 patients (8.2 %) patients had radiological evidence of lysis. Relative risk of developing lysis was 6.7 times higher in HACS group. Conclusion. Percutaneous SIJ fixation procedure has been shown to have good clinical outcomes and TTD leads to significantly better patient reported outcomes compared to HACS. There is a 6.7 time higher risk of lysis with use of HACS and lysis is a risk factor for poor outcomes

Patients undergoing revision surgery of a primary total hip arthroplasty often exhibit bone loss and poor bone quality, which make achieving stable fixation and osseointegration challenging. Implant components coated in porous metals are used clinically to improve mechanical stability and encourage bone in-growth. We compared ultra-porous titanium coatings, known commercially as Gription and Porocoat, in an intra-articular model by press-fitting coated cylindrical implants into ovine femoral condyles and evaluating bone in-growth and fixation strength 4, 8 and 16 weeks post-operatively. Bilateral surgery using a mini-arthrotomy approach was performed on twenty-four Dorset-Rideau Arcott rams (3.4 ± 0.8 years old, 84.8 ± 9.3 kg) with Institutional Animal Care Committee approval in accordance with the Canadian Council on Animal Care. Cylindrical implants, 6.2 mm in diameter by 10 mm in length with surface radius of curvature of 35 mm, were composed of a titanium substrate coated in either Porocoat or Gription and press-fit into 6 mm diameter recipient holes in the weight-bearing regions of the medial (MFC) and lateral (LFC) femoral condyles. Each sheep received 4 implants; two Gription in one stifle (knee) and two Porocoat in the contralateral joint. Biomechanical push-out tests (Instron ElectroPuls E10000) were performed on LFCs, where implants were pushed out relative to the condyle at a rate of 2 mm/min. Force and displacement data were used to calculate force and displacement at failure, stiffness, energy, stress, strain, elastic modulus, and toughness. MFCs were fixed in 70% ethanol, processed undecalcified, and polished sections, approximately 70 µm thick (Exakt Micro Grinding system) were carbon-coated. Backscattered electron images were collected on a scanning electron microscope (Hitachi SU3500) at 5 kV and working distance of 5 mm. Bone in-growth within the porous coating was quantified using software (ImageJ). Statistical comparisons were made using a two-way ANOVA and Fisher's LSD post-hoc test (Statistica v.8). Biomechanical evaluation of the bone-implant interface revealed that by 16 weeks, Gription-coated implants exhibited higher force (2455±1362 N vs. 1002±1466 N, p=0.046) and stress (12.60±6.99 MPa vs. 5.14±7.53 MPa, p=0.046) at failure, and trended towards higher stiffness (11510±7645 N/mm vs. 5010±8374 N/mm, p=.061) and modulus of elasticity (591±392 MPa vs. 256±431 MPa, p=0.61). Similarly, by 16 weeks, bone in-growth in Gription-coated implants was approximately double that measured in Porocoat (6.73±3.86 % vs. 3.22±1.52 %, p=0.045). No statistically significant differences were detected at either 4 nor 8 weeks, however, qualitative observations of the exposed bone-implant interface, made following push-out testing, showed more bony material consistently adhered to Gription compared to Porocoat at all three time points. High variability is attributed to implant placement, resulting from the small visual window afforded during surgery, unique curvatures of the condyles, and presence of the extensor digitorum longus tendon which limited access to the LFC. Ultra-porous titanium coatings, know commercially as Gription and Porocoat, were compared for the first time in a challenging intra-articular ovine model. Gription provided superior fixation strength and bone in-growth, suggesting it may be beneficial in hip replacement surgeries where bone stock quality and quantity may be compromised

Introduction. Trabecular Titanium is a biomaterial characterized by a regular three-dimensional hexagonal cell structure imitating trabecular bone morphology. Components are built via Electron Beam Melting technology in aone- step additive manufacturing process. This biomaterial combines the proven mechanical properties of Titanium with the elastic modulus provided by its cellular solid structure (Regis 2015 MRS Bulletin). Several in vitro studies reported promising outcomes on its osteoinductive and osteoconductive properties: Trabecular Titanium showed to significantly affect osteoblast attachment and proliferation while inhibiting osteoclastogenesis (Gastaldi 2010 J Biomed Mater Res A, Sollazzo 2011 ISRN Mater Sci); human adipose stem cells were able to adhere, proliferate and differentiate into an osteoblast-like phenotype in absence of osteogenic factors (Benazzo 2014 J Biomed Mater Res A). Furthermore, in vivo histological and histomorphometric analysis in a sheep model indicated that it provided bone in-growth in cancellous (+68%) and cortical bone (+87%) (Devine 2012 JBJS). A multicentre prospective study was performed to assess mid-term outcomes of acetabular cups in Trabecular Titanium after Total Hip Arthroplasty (THA). Methods. 89 patients (91 hips) underwent primary cementless THA. There were 46 (52%) men and 43 (48%) women, with a median (IQR) age and BMI of 67 (57–70) years and 26 (24–29) kg/m2, respectively. Diagnosis was mostly primary osteoarthritis in 80 (88%) cases. Radiographic and clinical evaluations (Harris Hip Score [HHS], SF-36) were performed preoperatively and at 7 days, 3, 6, 12, 24 and 60 months. Bone Mineral Density (BMD) was determined by dual-emission X-ray absorptiometry (DEXA) according to DeLee &Charnley 3 Regions of Interest (ROI) postoperatively at the same time-points using as baseline the measureat 1 week. Statistical analysis was carried out using Wilcoxon test. Results. Median (IQR) HHS and SF-36 improved significantly from 48 (39–61) and 49 (37–62) preoperatively to 99 (96–100) and 76 (60–85) at 60 mo. (p≤0.0001). Radiographic analysis showed evident signs of bone remodelling and biological fixation, with presence of superolateral and inferomedial bone buttress, and radial trabeculae in ROI I/II. All cups resulted radiographically stable without any radiolucent lines. The macro-porous structure of this biomaterial generates a high coefficient of friction (Marin 2012 Hip Int), promoting a firm mechanical interlocking at the implant-bone interface which could be already observed in the operating room. BMD initially declined from baseline at 7 days to 6 months. Then, BMD slightly increased or stabilized in all ROIs up to 24 months, while showing evidence of partial decline over time with increasing patient' age at 60 months, although without any clinical significance in terms of patients health status or implant stability. Statistical significant correlations in terms of bone remodeling were observed between groups of patients on the basis of gender and age (p≤0.05). No revision or implant failure was reported. Conclusions. All patients reported significant improvements in quality of life, pain relief and functional recovery. Radiographic evaluation confirmed good implant stability at 60 months. These outcomes corroborate the evidence reported on these cups by orthopaedic registries and literature (Perticarini 2015 BMC Musculoskelet Disord; Bistolfi 2014 Min Ortop)

It is very important to fix implant to bone. Bioactive materials as hydroxyapatite or glass-ceramics have bone-bonding ability. Hydroxyapatite-coating is applied to cementless THA or TKA. I and coworkers investigated bone-bonding mechanism of bioactive material and found that bone-like apatite formation play key role for bonding. If the surface of metal is changed to form apatite on it in body, the inert metal changes into bone-bonding material. We developed alkaline and heat treatment of titanium to change titanium to bone –bonding material as follows. At first, titanium is dipped in 5N NaOH solution for 24 hours, at second the metal is washed in pure water and finally it is sintered in 500 degree C for 2 hours. The treated surface has bioactivity, bone bonding ability like hydroxyapatite. The advantage of this treatment over hydroxyapatite-coating procedure is to treat the porous surface without any change of pore figures. As to hydroxyapatite-coating procedure, pore of the small diameter is filled with hydroxyapatite and pore figures are change. We applied this alkaline and heat treatment to cementless THA and its good results of more than ten years was reported. Porous titanium can be changed to bioactive material by alkaline and heat treatment. This bioactive porous titanium was found to have a property of material-induced osteoinduction, that is, the bone formation in pore of porous titanium implanted in canine back muscle. They can be used for bone substitute for big bone defect. We used two procedures to make porous titanium, sintering of titanium powder with spacer particle of ammonium sulfate and selective lazar melting. The latter procedure can produce any type of pore structure of titanium. Selective laser melting was employed to fabricate porous Ti implants (diameter 3.3 mm, length 15 mm) with a channel structure comprising four longitudinal square channels, representing pores, of different diagonal widths, 500, 600, 900, and 1200 micrometer. These were then subjected to chemical and heat treatments to induce bioactivity. Significant osteoinduction was observed in widths 500 and 600 micrometer, with the highest observed osteoinduction occurring at 5 mm from the end of the implants. A distance of 5 mm probably provides a favorable balance between blood circulation and fluid movement. New bioactive bone cement is another topic of the application of bioactive titanium in this lecture. The bone cement contains barium sulphate for radiocontrast. We developed a procedure to replace barium sulphate with bioactive titanium powder. This new bone cement has not only better biocompatibility than conventional cement but also bone bonding ability. It is potent material for the fixation of implant to bone. I will speak the evaluation of this cement using canine model of THA

Corrosion in modular taper connections of total joint replacement has become a hot topic in the orthopaedic community and failures of modular systems have been reported. The objective of the present study was to determine in vivo titanium ion levels following cementless total hip arthroplasty (THA) using a modular neck system. A consecutive series of 173 patients who underwent cementless modular neck THA and a ceramic on polyethylene bearing was evaluated retrospectively. According to a standardized protocol, titanium ion measurements were performed on 67 patients using high-resolution inductively coupled plasma-mass spectrometry. Ion levels were compared to a control group comprising patients with non-modular titanium implants and to individuals without implants. Although there was a higher range, modular-neck THA (unilateral THA: 3.0 μg/L (0.8–21.0); bilateral THA: 6.0 μg/L (2.0–20.0)) did not result in significant elevated titanium ion levels compared to non-modular THA (unilateral THA: 2.7 μg/L (1.1–7.0), p = 0.821; bilateral THA: 6.2 μg/L, (2.3–8.0), p = 0.638). In the modular-neck THA group, patients with bilateral implants had significantly higher titanium ion levels than patients with an unilateral implant (p < 0.001). Compared to healthy controls (0.9 μg/L (0.1–4.5)), both modular THA (unilateral: p = 0.029; bilateral p = 0.003) and non-modular THA (unilateral: p < 0.001; bilateral: p < 0.001) showed elevated titanium ion levels. The data suggest that the present modular stem system does not result in elevated systemic titanium ion levels in the medium term when compared to non-modular stems. However, more outliner were seen in modular-neck THA. Further longitudinal studies are needed to evaluate the use of systemic titanium ion levels as an objective diagnostic tool to identify THA failure and to monitor patients following revision surgery

Abstract. Background. Prospective study to compare patient reported outcome measures (PROM) for sacroiliac joint (SIJ) fusion using HA-coated screw (HACS) vs triangular titanium dowel (TTD). First study of its kind in English literature. Methods. 40 patients underwent SIJ stabilisation using HACS and TTD was used in 70 patients at CAVUHB, Cardiff. PROMs were collected prospectively before surgery and 12 months post-op. Short Form (SF)-36, Oswestry Disability Index, EuroQol-5D-5L and Majeed Pelvic Scores were collected. Shapiro-wilk test was used to determine normality of data. Mann-whitney U test was used to compared non-parametric data and Independent sample T test for parametric data. Results. 33 patients in HACS group and 61 in TTD group completed follow-up. There was no significant difference in all preoperative PROMs in both groups hence the data was considered comparable. All postoperative PROMs were significantly higher in TTD group. In HACS group, 21 patients (63%) had lysis around screw and sub-group analysis showed that PROMs were lower in patients with lysi. 4 patients with lysis around screw were offered revision due to ongoing pain. Revision was successful in only 1 patient. In TTD group only 5 patients (8.2 %) patients had radiological evidence of lysis. Relative risk of developing lysis was 6.7 times higher in HACS group. Conclusion. Percutaneous SIJ fixation procedure has good clinical outcomes and TTD leads to significantly better patient reported outcomes compared to HACS. There is a 6.7 time higher risk of lysis with use of HACS and lysis is a risk factor for poor outcomes

Titanium knee, shoulder and hip implants are typically grit-blasted, thermal plasma spray coated, or sintered to provide ingrowth surface features having texture with pore sizes on the order of hundreds of micrometers. This provides macro and micro-mechanical locking upon bone remodeling. However, at the nanoscale and cellular level, these surfaces appear smooth. In vitro and in vivo research shows surfaces with nanoscale features result in enhanced osseointegration, greater bone-implant contact area and pullout force, and the potential to be bactericidal via a simple hybrid anodization surface modification process. Prior processes for creating nanotube nano-textured surfaces via electrochemical anodization relied on hydrofluoric acid electrolyte and platinum cathodes. This novel process uses ammonium fluoride electrolytes and graphite cathodes which are more cost effective and easier to handle during processing. Hybrid electrolytes with differing concentrations of ethylene glycol, water, and ammonium fluoride provide a variety of nanotube morphologies and sizes. Nano-tubular surfaces on knee tibial and femoral implants, hip stems and acetabular cups, bone screws and other 3D printed parts have been enhanced by this method of nano-texturing in as little as 30 minutes. In vivo work in a Sprague Dawley rat model showed bone-implant contact area up to 2.9-times greater, and uniaxial pullout forces up to 6.9-times greater, than implanted smooth titanium controls at 4 and 12-week time points. In these tests, 1.25mm Kirschner wires were implanted in the rat femora to simulate an intramedullary nail. Histomorphometry in the mid-shaft and distal regions showed greater trabecular thickness and bone tissue mineral density than controls. Axial pullout tests often resulted in bone failure before the bone-implant interface. In vitro evidence suggests that nanoscale surfaces may have an antibacterial effect due to surface energy changes that reduce the ability of bacteria to adhere. However, it is recognized that silver is highly antibacterial in appropriate concentrations. It is also recognized that nanosilver, approximately 10–20nm, is especially effective. Ammonium fluoride anodization is modified using a hybrid electrolyte that includes silver fluoride. By substituting some of the ammonium fluoride with silver fluoride, to maintain a constant total fluorine mass, nanosilver is integrated within and among the nanotubes in the same single process that forms the nanotubes. This hybrid process in nano-texturing titanium implants can be integrated into current manufacturing production at low cost

INTRODUCTION. Trabecular Titanium is an open-cell regular structure composed by hexagonal cells of controlled pore, manufactured by Electron Beam Melting (EBM) technology, that allows moulding of cellular solid structures. The Lima Delta TT revision cups are One and Revision, which is characterized by a caudal hook and fins. Both allow internal modularity and cranial TT augments. The aim of this prospective study is to evaluate the short to medium-term clinical and radiographic outcomes of acetabular revision cups in TT. METHODS. Between December 2008 and March 2013 we performed 60 cup revisions, 33 with the Revision cup and 27 with the One cup. The bone defect was classified according to Paprosky acetabular classification: type IIb and IIc presenting continent anterior and posterior acetabular wall were treated by Delta One TT; type IIIa and IIIb were treated with Delta TT Revision. In 20 cases (3.3%) stem revision was associated. Causes of revision were: aseptic loosening in 48 cases, periprosthetic acetabular fractures in 5 cases, recurrent dislocation in 5 cases, infection in 2 cases. In 52 cases bone grafts were used to fill cavitary defects (AIR 1–4). Hemispheric TT augments were used in 13 cases with the same aim. Internal modules were used in 39 cases to restore correct offset. The mean age of patients was 69.6 years (range 29–90). The average follow-up was 39 months (range 19–70). RESULTS. Mean Harris Hip Score (HHS) was 39.9 preoperatively and 82.7 at last follow-up. We had no intraoperative complications. We had 2 cases of superficial infection, one of which required revision of the surgical wound. 4 patients suffered dislocation episodes (1 recurrent); none of them required revision. We had 1 case of asymptomatic aseptic loosening, which did not require intervention. In the remaining cases no radiographic evidence of radiolucent lines was noticed at follow up, neither any evidence of aseptic loosening. The graft was considered to be integrated in all cases. DISCUSSION AND CONCLUSION. Trabecular Titanium revision cups showed high capacity of osseointegration, providing good results in short to medium-term follow-up. Further studies are necessary to assess long-term survivorship

Periprosthetic joint infection (PJI) remains one of the most devastating complications that can occur following total joint arthroplasty. Failure rate of standard treatment for PJI is estimated to be around 40% at two years post revision surgery. A major clinical challenge contributing to treatment failure and antibiotics tolerance is the biofilm formation on implant surfaces. Lytic bacteriophages (phages) can target biofilm associated bacteria at localized sites of infection by penetrating and disrupting biofilm matrices; furthermore, phage replication within the biofilm leads to high local concentrations resulting in a powerful therapeutic effect. The aim of this study is to test if phage cocktail has better antimicrobial effect than vancomycin or a single agent phage against biofilm forming MRSA clinical strain Staphylococcus aureus (S. aureus). S. aureus BP043 was utilized in this study. This strain is a PJI clinical isolate, methicillin resistant (MRSA) and biofilm-former. Three lytic phages, namely, 44AHJD, Team1 and P68, known to infect S. aureus, were tested for their efficiency against S. aureus BP043. The ability of the phages to eliminate S. aureus BP043 planktonic or biofilm cultures was tested either as singular phages or as a cocktail of the three phages. Planktonic cells were adjusted to ∼ 1×109 CFU/mL in tryptic soy broth (TSB) and each phage was added alone or as a cocktail at ∼ 1×109 PFU/mL with moi of 1 (a multiplicity of infection). Bacterial growth was assessed by measuring optical densities at 24hr and was compared to the control of S. aureus BP043 with no phage. BP043 biofilms was grown for 24hr on plasma sprayed titanium (Ti-6Al-4V) alloy disc surfaces. Mature biofilms were then treated with one of the three phages or a cocktail of the 3 phages for 24hr at ∼ 1×109 PFU/mL in TSB. Then, biofilms were dislodged, and bacterial survival was assessed by plating on tryptic soy agar plates. Survival in treated biofilms was compared to control biofilm that was exposed only to TSB. Planktonic cells growth in the presence of phage 44AHJD was reduced significantly (p <0.0001) after 24hr compared to the control. The other two phages did not show a similar pattern when used alone. The reduction in growth was more pronounced when the three phages were combined together (p <0.0001, compared to the control, p=0.011 3, 44AHJD alone versus 3 phages). Exposing BP043 biofilm to the phage cocktail resulted in more than three logs (CFU/mL) reduction in bacterial load residing in the biofilm while no effect was detected when either vancomycin or each phage was used solely. We have demonstrated that the usage of lytic phage cocktail contributes to better clearance of planktonic cultures of the S. aureus MRSA isolate. More importantly, viable bacteria in the biofilms that were grown on plasma sprayed titanium discs were reduced by more than 37% when a phage cocktail was used compared to using a single phage or vancomycin. This work is aimed at gathering preclinical evidence for using phage as a new therapeutic avenue to treat PJI

PEEK rods construct has been proposed to allow better load sharing among spinal components when compared to the more traditional Titanium rods constructs. However, such proposal has largely derived from single-load in-vitro testing and the biomechanical differences between the two constructs when subjected to fatigue loading remain unknown. Current study comparatively analyzed the in-vitro biomechanical performance of PEEK and Titanium rod constructs as spinal implants through a 5 hour fatigue loading test. The disc height and intradiscal pressure of the instrumented and adjacent levels pre- and post-loading were recorded for analysis. The stress levels on the rods and bone stress near the screw-bone interface were also collected to investigate the likely failure rates of the two constructs. The results showed that the Titanium rods construct demonstrated a minimum amount of loss of disc height and intradiscal pressure at the instrumented level, however, a significant loss of the disc height and intradiscal pressure at adjacent levels compared to the intact spine were identified. In contrast, the disc height and intradiscal pressure of the PEEK rods were found to be comparable to those of the intact spine for all levels. The PEEK rods group also showed significantly less bone stress near the screw-bone interface compared to the Titanium rods group. Current study has demonstrated the potential benefits of the PEEK rods construct in reducing the risks of adjacent segment disease and implant failure rates when compared to the more traditional Titanium rods construct