Objectives. The purpose of this study was to evaluate in vivo biocompatibility of novel single-walled carbon nanotubes (SWCNT)/poly(lactic-co-glycolic acid) (PLAGA) composites for applications in bone and tissue regeneration. Methods. A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight and 12 weeks post-implantation were compared with control (Sham) and PLAGA (five rats per group/point in time). Rats were observed for signs of morbidity, overt toxicity, weight gain and food consumption, while haematology, urinalysis and histopathology were completed when the animals were killed. Results. No mortality and clinical signs were observed. All groups showed consistent weight gain, and the rate of gain for each group was similar. All groups exhibited a similar pattern for food consumption. No difference in urinalysis, haematology, and absolute and relative organ weight was observed. A mild to moderate increase in the summary toxicity (sumtox) score was observed for PLAGA and SWCNT/PLAGA implanted animals, whereas the control animals did not show any response. Both PLAGA and SWCNT/PLAGA showed a significantly higher sumtox score compared with the control group at all time intervals. However, there was no significant difference between PLAGA and SWCNT/PLAGA groups. Conclusions. Our results demonstrate that SWCNT/PLAGA composites exhibited in vivo biocompatibility similar to the Food and Drug Administration approved biocompatible polymer, PLAGA, over a period of 12 weeks. These results showed potential of SWCNT/PLAGA composites for bone regeneration as the low percentage of SWCNT did not elicit a localised or general overt toxicity. Following the 12-week exposure, the material was considered to have an acceptable biocompatibility to warrant further long-term and more invasive in vivo studies. Cite this article: Bone Joint Res 2015;4:70–7

Introduction. Support of appositional bone ingrowth and resistance to bacterial adhesion and biofilm formation are preferred properties for biomaterials used in spinal fusion surgery. Although polyetheretherketone (PEEK) is a widely used interbody spacer material, it exhibits poor osteoconductive and bacteriostatic properties. In contrast, monolithic silicon nitride (Si. 3. N. 4. ) has shown enhanced osteogenic and antimicrobial behavior. Therefore, it was hypothesized that incorporation of Si. 3. N. 4. into a PEEK matrix might improve upon PEEK's inherently poor ability to bond with bone and also impart resistance to biofilm formation. Methods. A PEEK polymer was melted and compounded with three different silicon nitride powders at 15% (by volume, vol.%), including: (i) α-Si. 3. N. 4. ; (ii) a liquid phase sintered (LPS) ß-Si. 3. N. 4. ; and (iii) a melt-derived SiYAlON mixture. These three ceramic powders exhibited different solubilities, polymorphic structures, and/or chemical compositions. Osteoconductivity was assessed by seeding specimens with 5 × 10. 5. /ml of SaOS-2 osteosarcoma cells within an osteogenic media for 7 days. Antibacterial behavior was determined by inoculating samples with 1 × 10. 7. CFU/ml of Staphylococcus epidermidis (S. epi.) in a 1 × 10. 8. /ml brain heart infusion (BHI) agar culture for 24 h. After staining with PureBlu™ Hoechst 33342 or with DAPI and CFDA for SaOS-2 cell adhesion or bacterial presence, respectively, samples were examined with a confocal fluorescence microscope using a 488 nm Krypton/Argon laser source. Images were also acquired using a FEG-SEM in secondary and backscattered modes on gold sputter-coated specimens (∼20–30Å). Hydroxyapatite (HAp) deposition was measured using a laser microscope. Raman spectra were collected for samples in backscattering mode using a triple monochromator using a 532 nm excitation source (Nd:YVO. 4. diode-pumped solid-state laser). Results. PEEK composites with 15 vol.% α-Si. 3. N. 4. , LPS ß-Si. 3. N. 4. , or the SiYAlON mixture showed significantly greater SaOS-2 cell proliferation (>600%, p<0.003, cf., Fig. 1(a)) and HAp deposition (>100%, p<0.003, cf., Fig. 1(b)) relative to monolithic PEEK. The largest increase in cell proliferation was observed with the SiYAlON composite, while the greatest amount of HAp was found on the LPS ß-Si. 3. N. 4. composite. Following exposure to S. epidermidis, the composite containing the LPS β-Si. 3. N. 4. powder showed one order of magnitude reduction in adherent live bacteria (p<0.003, cf., Fig. 1(c)) as compared to the PEEK monolith. It is interesting to note that the composite containing α-Si. 3. N. 4. exhibited the worst bacterial resistance (i.e., ∼100% higher than monolithic PEEK), suggesting that the bacteriostatic effectiveness of Si. 3. N. 4. bioceramics is apparently dependent upon the presence of selective sintering additives, viz. yttria and alumina. Conclusions. The addition of 15 wt.% of specific Si. 3. N. 4. powders to PEEK showed enhanced SaOS-2 cell adhesion, proliferation, and HAp deposition when compared to monolithic PEEK. These same composites also showed resistance to S. epi. adhesion and biofilm formation.. Although improvements in osteoconductivity have been previously observed by compounding or coating PEEK with HAp, titanium, or tantalum, these approaches did not provide anti-microbial properties. Compounding PEEK with Si. 3. N. 4. represents a significant advancement due to its ability to provide both improved bone apposition and resistance to biofilm formation. For any figures or tables, please contact the authors directly

Aim. Treatment principles of chronic osteomyelitis include debridement, clean sampling, excision of dead bone, stabilization, dead space management, soft tissue closure and systemic antibiotic therapy. Dead space management becomes very complicated, if the bone infection is caused by multi-resistant bacteria. The aim of this investigation was to evaluate the effect of a new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. in the treatment of chronic osteomyelitis (OM) caused by multi-resistant bacteria. Method. From June 2015 to November 2015, 7 patients (4 males, 3 females, average age 52.6y) were treated according to the above mentioned principles using the new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. Infections were caused by methicillin-resistant Staphylococcus aureus (MRSA), multi-resistant Staphylococcus epidermidis (MRSE) and polymicrobial, vancomycin-sensitive bacteria. We used a two-stage protocol with debridement, excision of bone and external stabilization in the first stage, followed by bone defect reconstruction. To fill the residual bone defects, in 3 patients the new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. (10mL) was used on its own and in 4 patients combined with 18mL of an unloaded calcium sulfate / hydroxyapatite composite. **. Post-operative follow-up was evaluated clinically and by radiographs and CT scans at 6, 14 and 24 weeks. Results. In 6 of 7 patients rapid control of infection was achieved. Soft tissue reactions and prolonged white wound drainage (caused by calcium sulfate dissolution) was seen in 3 of 7 patients. In 6 of 7 patients recurrence of infection has not been observed so far. Radiographs showed different elution intervals of the radiocontrast agent (Iohexol), depending on anatomical location. Bone remodelling or replacement of the composite by new bone was not uniform in the patients and showed specific radiographic signs. In addition to the so-called „puddle sign“, we found septae, membranes, vacuoles and sometimes arc-like structures. Therefore, we suggest the name “arc-sign” for these formations. Conclusions. During the follow-up of the first 7 patients treated with the unloaded calcium sulfate / hydroxyapatite composite. **. in 6 of 7 cases no recurrence of infection was observed. This is very promising in the difficult situation of bone infections caused by multi-resistant bacteria. Follow-up radiographs and CT-scans showed specific patterns during the resorption of the composite and the formation of new bone, which have not been described in other bone graft substitutes so far. The bone defects are not completely filled yet, but the affected bones are clinically stable and patients can ambulate with full weight bearing

Aim. Reconstruction of composite soft-tissue defects with extensor apparatus deficiency in patients with periprosthetic joint infection (PJI) of the knee is challenging. We present a single-centre multidisciplinary orthoplastic treatment concept based on a retrospective outcome analysis over 20 years. Method. One-hundred sixty-seven patients had PJI after total knee arthroplasty. Plastic surgical reconstruction of a concomitant perigenicular soft-tissue defect was indicated in 49 patients. Of these, seven presented with extensor apparatus deficiency. Results. One patient underwent primary arthrodesis and six patients underwent autologous reconstruction of the extensor apparatus. The principle to reconstruct missing tissue ‘like with like’ was thereby favoured: Two patients with a wide soft-tissue defect received a free anterolateral thigh flap with fascia lata; one patient with a smaller soft-tissue defect received a free sensate, extended lateral arm flap with triceps tendon; and three patients received a pedicled medial sural artery perforator gastrocnemius flap, of which one with Achilles tendon. Despite good functional results 1 year later, long-term follow-up revealed that two patients had to undergo knee arthrodesis because of recurrent infection and one patient was lost to follow-up. In parts, results have been published under doi: 10.7150/jbji.47018. Conclusions. A treatment concept and its rationale, based on a single-centre experience, is presented. It differentiates between various types of soft-tissue defects and shows reconstructive options following the concept to reconstruct ‘like with like’. Despite good results 1 year postoperatively, PJI of the knee with extensor apparatus deficiency remains a dreaded combination with a poor long-term outcome

Background. Composite screws of uncalcined and unsintered hydroxyapatite (HA) particles and poly-l-lactide (PLLA) were developed as completely absorbable bone fixation devices. So far the durability of HA-PLLA composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation. Methods. During 2003–2009, HA-PLLA composite screws were used for fixation of acetabular bone graft in cemented or reverse-hybrid primary THA in 106 patients (114 cases). All the THAs were performed through direct lateral approaches, and postoperative gait exercise with full weight bearing usually started two days after surgery. One patient died of an unrelated disease and seven patients were lost to follow-up within 5 years. Finally, 98 patients (106 cases) were followed up for over 5 years and were reviewed retrospectively (follow-up rate, 93%). Radiographic loosening of the acetabular component was assessed according to the criteria of Hodgkinson et al., and the radiolucent line around the socket was evaluated in all zones, as described by DeLee and Charnley. Results. The patient population comprised 10 men and 88 women with a mean age of 60.3 years (range, 41–81 years) at the time of surgery. The mean follow-up period was 7.6 years (range, 5–11 years). The original diagnosis for primary THA was secondary osteoarthritis in 97 cases and high hip dislocation in nine cases. No patient in this series required revision surgery, and no radiographical loosening occurred during the follow-up period. Grafted bone union was confirmed in all cases, and no apparent osteolysis around the cemented socket or composite screws was detected. Configurations of the HA-PLLA composite screws appeared obscure on radiographs at 5 years after surgery, and only osteosclerotic traces remained in the screw positions at the final follow-up. This finding was consistent in this series. The screw heads sometimes appeared to be broken with absorption within 3 years of surgery, and the remnants were identified in situ at the final follow up. Kaplan–Meier survival analyses with socket revision surgery for any reason, socket loosening, and appearance of a radiolucent line >1 mm in any zone as the endpoints yielded survival rates of 100%, 100%, and 86.8% at 5 years, and 100%, 100%, and 85.8% at 10 years, respectively. Conclusion. This absorbable screw seems to have no negative effects on the mid-term clinical results of cemented socket fixation

Objective. To compare the ability of a new composite bio-absorbable screw and two conventional metal screws to maintain fixation of scaphoid waist-fractures under dynamic loading conditions. Methods. Fifteen porcine radial carpi, with morphology comparable to human scaphoids, were osteotomised at the waist. Specimens were randomised in three groups: Group I were fixed with a headed metal screw, group II with a headless tapered metal screw and group III with a bio-absorbable composite screw. Each specimen was oriented at 45° and cyclically loaded using four blocks of 1000 cycles, with peak loads of 40, 60 (normal load), 80 and 100 N (severe load) respectively. Permanent displacement and translation (step-off) at the fracture site was measured after each loading block from a standardised high-magnification photograph using image analysis software (Roman v1.70, Institute of Orthopaedics, Oswestry). Statistical analysis was by ANOVA and tolerance limits. Results. No gross failure or fracture gap displacement occurred. Average translations (step-off) at the fracture site after 4000 cycles up to 100N were 0.05mm±0.02SD (headed metal), 0.14mm±0.14SD (headless metal) and 0.29mm±0.11SD (composite) and differed significantly (p<0.01). Using tolerance limits, the data allowed us to predict that, with 95% certainty, the maximum average translation (step-off) following severe loading in 95% of any sample fixed with a headed metal screw will be below 0.17mm, headless metal screw below 0.74mm, and composite screw below 0.76mm. Conclusion. We observed only small average translations (step-off) for all three screws. Moreover, translations of more than 1mm that would predispose to non-union were highly unlikely for any of the screws, even after severe cyclic loading. We therefore conclude that a new bio-absorbable composite screw can serve as an alternative to conventional screws when fixing scaphoid fractures

Introduction. Hydroxyapatite and poly-L-lactide (HA/PLLA) composites are osteoconductive and biodegradable. They have already been used clinically to treat fractured bones by inducing osteosynthesis and serving as the bone filling material. During revision of total hip arthroplasty, we have grafted bone onto the bone defect and covered it with an HA/PLLA mesh instead of using a metal mesh on the non-load bearing portion of the cup (Figure 1). However, whether the interface between the HA/PLLA and the titanium alloy cup was stable remains unclear. Objectives. The purpose of this study was to determine and compare the histological osteoconductivity and osteoinductivity of HA/PLLA and titanium alloy. Methods. Semicylindrical samples (diameter: 3 mm; height: 5 mm) were fabricated from a composite unsintered-HA/PLLA containing 40% fine HA particles and from titanium alloy (Ti-6AL-4V). These two samples were combined to form one cylinder (Figure 2). Defects 3 mm in diameter were drilled into both femoral condyles of nine Japanese white rabbits, and the samples were implanted by press fitting. The rabbits were euthanized at 2, 4, 8, and 25 weeks after implantation, and undecalcified ground samples were prepared. New bone formation was examined histologically using Toluidine blue and Villanueva Goldner stains. Results. New bone formation was observed around the sample at 4 weeks, and the amount increased by 8 weeks. In addition, partial remodeling of the trabecular bones and absorption of the HA/PLLA were found at 25 weeks. Small amounts of new bone formation were found at 4 weeks between the HA/PLLA and titanium alloy materials (Figure 3: Toluidine blue stain), and the amount increased at 8 and 25 weeks. The HA/PLLA had been slightly absorbed and new bone was formed in the gap, which was close to the border between the materials, at 25 weeks. However, the amount of absorption was limited, and no new bone was found in samples where the materials were firmly in contact. Conclusions. HA/PLLA was only slight absorbed at 25 weeks, suggesting that it was stable in vivo and has good osteoconductive and osteoinductive properties. No new bone was found in the regions where the sample was stable and had no gaps between the HA/PLLA and titanium alloy, probably because there was no space for new bone to form in those regions. In contrast, new bone formation was found in gaps of more than 20 μm. Clinically, many gaps likely exist, allowing new bone formation to occur even in a stable implant. This may stabilize the HA/PLLA and titanium alloy materials for longer times. As expected, the HA/PLLA and titanium alloy were mostly stablein vivo

Introduction. Third body wear caused by contaminated bearing environment with debris that may have been generated by a worn or fractured revised bearing coupling, but also originated by generation of metal/cement particles during the primary or revision surgery, may be a relevant issue for the implant life. Objectives. To evaluate the wear behavior of a last generation alumina matrix ceramic composite (AMC) bearing in a worst case scenario consisting of highly contaminated test lubricant with alumina particles in a hip joint simulator study. Methods. AMC (BIOLOX®delta - Group 1) and alumina (BIOLOX®forte - Group 2) liners with an internal diameter of 32mm were articulated against AMC BIOLOX®OPTION heads (all CeramTec GmbH, Plochingen). Coarse alumina particles (D(50):60µm) and fine alumina particles (D(50):0.30µm) with a concentration of 48mg/ml were used as environmental contamination of the first 2mlc and the second 2mlc, respectively. All components were tested according to ISO14242-1(2012) using the EndoLab®hip joint simulator. Each group consisted of 3 couples plus one axially loaded control consisting of a 32mm AMC head on an alumina liner. The test fluid was exchanged every 500'000 cycles. Two different test regimes describing level walking and subluxation of the insert from the femoral head were used as test input. The first regime included 500 standard walking cycles followed by a second block of 5 subluxation cycles. Head subluxation is assumed to increase the number of third-body particles that enter the otherwise closely conforming articular bearing space, when compared to level-walking cycles alone. To maintain the particle suspension in the test fluid, the test fluid of each test chamber was circulated by peristaltic pumps. The wear rate was determined by gravimetric method. The surface of ball heads was subjected to visual inspection every 500'000 cycles by optical and laser microscope. The depth of scratches was measured by the laser microscope. Results. After 2 million load cycles with the test fluid contaminated with coarse alumina particles, no significant wear was detected by the gravimetric method. The qualitative surface inspection by laser microscope individuated an increasing, but low concentration of sparse tiny scratches about 40nm deep on ball head surface at every simulator stop. Nevertheless, after loading the chambers with fine alumina particles, bearing surface wear seemed to increase consistently, since opaque areas appeared after 3 million load cycles, but the wear-rate remained close to the gravimetric measurement detection limit (about 0.1–0.2mg) indicating the still extremely low wear-rate of the tested ceramic couplings. Conclusions. This study confirms the high wear and scratch resistance of AMC used in THA. Even in heavily contaminated environment with hard alumina particles, which may occur after fracture of a ceramic component, gravimetry wasn't able to detect significant wear. The visual inspection by laser microscope exhibited only slight damaged surface characterized by tiny scratches and more opaque areas in the main wear zone as result of using fine alumina particles. Ceramic-on-ceramic is a safe bearing even in the case of revision for ceramic fracture, maintaining the excellent wear resistance of this bearing

The purpose of this study was to compare the clinical, radiographic, and DEXA results of Epoch® Femoral Component for primary THA with other non-cemented femoral components. The Epoch and Epoch 14+ (Zimmer, Warsaw, IN) Composite Femoral Components were studied in conjunction with the VerSys® Fiber Metal Taper, Fiber Metal Mid coat and Beaded Fullcoat Femoral Components (Zimmer, Warsaw, IN). All patients were randomized into one of five component groups and followed prospectively. All patients across the five groups were matched with respect to demographics and body mass index (BMI) (Table 1). Diagnoses were evenly distributed across all study groups. There was no significant change in BMD at 5-years when compared to the baseline (6 month) DEXA measurements for all component groups except for the Beaded Fullcoat component subset which had significant decreases in BMD in proximal zones 1, 6 and 7, The Fiber Metal Taper showed similar decreases in BMD in zones 1 and 7, and the Epoch Component had a significant decrease in BMD in zone 7 only. Additionally, our DEXA findings complement and support the subjective radiographic interpretations performed for this study cohort. The results from this prospective, randomized controlled clinical trial showed that the Epoch Composite Femoral Component for primary THA can achieve results equal to standard alloy components of varying design. Based on these early results, the Epoch and Epoch 14+ Femoral Components for primary THA are justified for continuance of further prospective study

Purpose. Traditionally, the gold standard for bone grafting has been either autografts or allografts. Whilst autografts are still widely used, drawbacks such as donor site morbidity are shifting the market rapidly toward the use of orthobiologic bone graft substitutes. This study investigated the in vivo performance of a novel (W02008096334) collagen-hydroxyapatite (CHA) bone graft substitute material as an osteoinductive tissue engineering scaffold. This highly porous CHA scaffold offers significantly increased mechanical strength over collagen-only scaffolds while still exhibiting an extremely high porosity (≈ 99%), and an osteoinductive hydroxyapatite phase [1]. This study assessed the ability of the CHA scaffolds to heal critical-sized (15 mm) long bone segmental defects in vivo, as a viable alternative to autologous bone grafts. Method. Collagen-HA (CHA) composite scaffolds were fabricated based on a previously-described freeze-drying technique [1]. After freeze-drying, these scaffolds were subjected to a dehydrothermal treatment and subsequently chemically crosslinked using EDAC. In vivo performance was assessed using a critical size segmental radial defect (15 mm) introduced into 16 young adult New Zealand White Rabbits under Irish Government license. Animals were divided into three groups; (i) an empty defect group (negative control), (ii) an autogenous bone graft group (positive control) and (iii) a CHA scaffold group (CHA). Segmental defect healing in all animals was assessed using plain X-Ray analysis, at four time-points (0, 6, 12 and 16 weeks). MicroCT and histological analysis were carried out at week 16. Results. Empty defect groups at all time points resulted in non-union of the segmental defect bone ends. Autogenous bone graft groups exhibited good filling of the segmental defect with extensive callus formation but even after 16 weeks showed poor remodelling. Although autogenous bone graft groups showed evidence of mineralized tissue within the defect, tissue healing appeared relatively uncontrolled (Figure 1a). CHA scaffold groups exhibited extensive bone healing as early as 6 weeks. By week 16, CHA defects showed complete bridging across the entire defect (figures 1b, 2b, 3b, 4b), development of a continuous marrow cavity (Figures 2b, 3b, 4b) and evidence of remodelling. Conclusion. The results of this study provide clear evidence that Collagen-HA scaffolds, can perform at least as well as autogenous bone grafts. This study provides strong evidence that after a relatively short time in vivo, CHA scaffolds can result in a more complete and homogenous bone healing response and have the potential to offer improved bone tissue formation above that of autogenous bone. More importantly, this study provides strong evidence that the use of low stiffness, organic, biodegradable scaffolds in fully load-bearing defects is not only successful but arguably produces significantly improved results when compared with the current Gold Standard, autogenous bone grafting

Purpose. To evaluate the efficacy of novel biodegradable MAACP/n-HA composite artificial lamina for the prevention of postlaminectomy adhesions and lamina reconstruction. Methods. Goats were randomly divided into three groups: an experimental group consisting of twelve goats that underwent cervical 4 laminectomies, followed by MAACP/n-HA composite artificial lamina implantations; a control group of nine goats whose cervical 4 vertebra plate were removed; and a normal group of three goats that did not receive any operations or treatments. On weeks 4, 12 and 24, two goats, two goats, three goats in the test group and two, two, two in the control group were selected using X-ray, CT, MRI and subsequently killed for histological examinations and SEM (scanning electronic microscopY). On week 24, the adhesion level of scar tissue was examined according to Rydell's degree of adhesion criteria. Biomechanical measurements were carried out at week 24 on 3 goats in the test group, 3 in the control group, and 3 in the normal group. Results. In the experimental group, the artificial lamina refrained from shifting, and no dural adhesion pressure was observed. New goat cervical natural bone formed in the defect and the bony spinal canal had reformed. In contrast, in the control group, fibrous scar tissue filled the defect and the scar tissue continued to exert pressure on the dura. Conclusions. Artificial lamina could prevent the epidural adhesions surrounding the defect and promote effectively bone tissue repair and new bone formation. MULTIPLE DISCLOSURES

The aim of our project is to develop resorbable nanostructured composite layer with controlled elution of antibiotics for implants survival rate enhancement. The nanostructured layers are expected to be used especially in the case of known systemic or local (joint) inflammation. This layer can provide a bone tissue/implant (titanium alloy) bioactive interface improving the physiological healing process and eliminating the risk of bacterial orthopedic infections. The main aim of this study was to verify whether the local concentration of released vancomycin exceeded the minimum inhibitory concentration (MIC) for vancomycin-resistant Staphylococcus aureus (VRSA, >16 mg/l). The layer is composed of collagen (type I, isolated form calf skin), hydroxyapatite nanoparticles and vancomycin hydrochloride (10 wt%). The stability of collagen was enhanced by EDC/NHS cross-linking. The in vitro release of vancomycin and crystalline degradation products from optimally cross-linked layers was investigated. An elution method and a high performance liquid chromatographic assay were employed to characterize the in vitro release rates of the vancomycin and its crystalline degradation antibacterial inactive products over a 21-day period. During the whole experimental period, the level of released vancomycin was high above the MIC for VRSA. The maximum average concentration was obtained between day 4 and day 8 and it reached 265 mg/l. At the end of the experiment (day 21), an average concentration of 104 mg/l was detected. Our study confirmed the prophylactic effects of studied vancomycin-loaded nanostructured layers

Introduction. Recently ventral plating implants made of carbon/PEEK composite material have been developed with apparently superior material properties in terms of implant fatigue and imaging suitability. In this study we assessed the outcome of the first clinical application of this new implant. Methods. Retrospective, single-center case series of 16 consecutive patients between 2011 and 2013 undergoing ventral stabilization surgery with a new carbon plating system (see figure 1). We collected data in terms of safety of the procedure (screw positioning, blood loss, operation time), quality and reliability of the implant (revisions, dislocations, screw loosening, fusion, adjacent segment degeneration), clinical outcome and biological tolerance (cervical pain / discomfort, dysphagia). Results. All patients were available for clinical and radiological follow up. Mean surgery time was 128 minutes, in 11 cases one in 5 cases 2 segments were treated. The clinical findings and patient's satisfaction were good in 14 and fair in two cases. All patients who completed the 6 months control had a radiographically confirmed interbody fusion; no implant loosening or failure and no infections were observed. (see figure 2). There was one implant related complication (dysphagia due to malpositioning of the plate which was removed 4 days after implant insertion) and one complication related to the approach (Horner's syndrome). Conclusion. In this retrospective study of 16 patients we found that the use of a carbon-composite plating system lead to results comparable to the “gold standard” metal plates in terms of safety / clinical outcome and reliability of the implant. There was one revision due to dysphagia. The MR imaging of the patients who have been operated with the carbon/PEEK system showed superior quality with reduced artifacts and improved diagnostical properties, especially when evaluating the neurogical structures. (see figure 3). The overall clinical outcome and patient acceptance of the implant was good. The radiologic findings on follow up of 2, 6 and 12 months have shown a high fatigue strength with no signs of implant failure in terms of dislocation, loosening or breakage. Therefore we conclude that the use of the carbon/PEEK plating system is suitable for ventral stabilization in trauma and degenerative disease

Introduction. Traditional applied loading of the knee joint in experimental testing of RTKR components is usually confined to replicating the tibiofemoral joint alone. The second joint in the knee, the patellofemoral joint, can experience forces of up to 9.7 times body weight during normal daily living activities (Schindler and Scott 2011). It follows that with such high forces being transferred, particularly in high flexion situations such as stair climbing, it may be important to also represent the patellofemoral joint in all knee component testing. This research aimed to assess the inclusion of the patellofemoral joint during in vitro testing of RTKR components by comparing tibial strain distribution in two experimental rigs. The first rig included the traditional tibiofemoral joint loading design. The second rig incorporated a combination of both joints to more accurately replicate physiological loading. Five implanted tibia specimens were tested on both rigs following the application of strain gauge rosettes to provide cortical strain data through the bone as an indication of the load transfer pattern. This investigation aimed to highlight the importance of the applied loading technique for pre-clinical testing and research of knee replacement components to guide future design and improve patient outcomes. Methods. Five composite tibias (4th Generation Sawbones) were prepared with strain gauge rosettes (HBM), correctly aligned and potted using guides for repeatability across specimens. The tibias were then implanted with Stryker Triathlon components according to surgical protocol. The first experimental rig was developed to replicate traditional knee loading conditions through the tibiofemoral joint in isolation. The second experimental rig produced an innovative method of replicating a combination of the tibiofemoral and patellofemoral joint loading scenarios. Both rigs were used to assess the load distribution through the tibia using the same tibia specimens and test parameters for comparison integrity (Figure 1). The cortical strains were recorded under an equivalent 500 N cyclical load applied at 10° of flexion by a hydraulic test machine. Results. The average results comparing both experimental rigs at three strain gauge locations are shown in Figure 2. Paired t-tests were performed on all results and a p value of p<0.05 was considered significant. No significant differences were found between the rigs. There was a trend towards a reduction in proximal principal strain with the inclusion of the patellofemoral joint (p=0.058). Discussion. The results of this study indicate that there is no significant difference in tibial load transfer between the traditional and novel applied loading techniques at small flexion angles. There is a trend towards a reduction in proximal strain when including the patellofemoral joint. This reduction may be linked to the patella tendon force counteracting the effect of tibiofemoral loading at this small flexion angle. At high flexion angles the patellofemoral reaction load increases significantly relative to the tibiofemoral load. This will have a significant effect on tibial strains and so it is recommended that testing at higher flexion angles should be performed in a combined loading rig

Aim. Open fractures with bone defects and skin lesions carry a high risk of infection potentially leading to prolonged hospitalization and complication requiring revision procedures. Treatment options for diaphyseal fractures with soft tissue lesions are one- or two-stage approaches using external fixation or intramedullary nailing. We describe a surgical technique combining intramedullary nailing with an antibiotic-eluting biphasic bone substitute (BBS) applied both at the fracture site, for dead-space management and infection prevention, and on the nail surface for the prophylaxis of implant-related infection. Method. Adult patients with an increased risk of bony infection (severe soft tissue damage and open fractures of Gustilo-Anderson grades I and II) were treated with debridement followed by application on the intramedullary nail surface, in the canal and at the fracture site of a BBS with prolonged elution (to 28 days) of either gentamicin or vancomycin. All patients also received systemic antibiotic prophylaxis following surgery. Data on infections and other adverse events were collected throughout the follow-up period. Bone union was determined by radiographic assessment of 4 cortices in radiographs obtained 1 year after surgery. Results. In this prospective, non-randomized case series a total of 6 patients were treated: 4 tibia (2 male, 2 female), 1 femur (female) and 1 humerus (male). The mean age of the patients was 28 years (range 18–51 years). Two patients had a history of smoking and 1 patient had a history of diabetes. Minimal Follow up was 12 months (range: 12 – 30 months). One to two weeks postoperatively, partial load bearing (20 kg) was allowed with free mobility of joints. Bone samples from the fracture site following debridement showed the presence of bacteria in 2 cases. No infections were observed during follow-up. Radiographs showed that the bone substitute was resorbed and also a gradual bony union of the fractures. All patients had good clinical outcomes. Conclusions. The addition of a BBS which elutes antibiotic locally in the dead-space of exposed fractures and at the implant surface prevents bacterial colonization and biofilm formation. The injectable composite we used enhances safety in higher risk patients, is easy to use in combination with intramedullary nailing and offers the opportunity for a one-stage procedure. Local administration of antibiotics at the fracture site provides an additional tool to manage difficult-to-treat complex fractures and implant-related infections. Larger studies are needed to confirm these results. *CERAMENT G or V, BONESUPPORT AB

The disadvantage of removing a well-fixed femoral stem are multiple (operating time, risk of fracture, bone and blood loss, recovery time and post-op complications. Ceramic heads with titanium adapter sleeves (e.g. BIOLOX®OPTION, Ceramtec) are a possibility for putting a new ceramic head on slightly damaged used tapers. ‘Intolerable’ taper damages even for this solution are qualitatively specified by the manufacturers. The aim of this study was to determine the fracture strength of ceramic heads with adapter sleeves on stem tapers with such defined damage patterns.

Pristine stem tapers (Ti-6Al-4V, 12/14) were damaged to represent the four major stem taper damage patterns specified by the manufacturers: -

‘Truncated’: Removal of 12.5% of the circumference along the entire length of the stem taper at a uniform depth of 0.5mm parallel to the taper slope.

BIOLOX®OPTION heads (Ø 32mm, length M) with Ti adapter sleeves were assembled to the damaged stem tapers and subjected to ISO7206-10 ultimate compression strength testing.

The forces required to fracture the head were high and caused complete destruction of the ceramic heads in all cases. The ‘Truncated’ group showed the lowest values (136kN ± 4.37kN; Fig. 3). Forces were higher and similar for the ‘Cut’ (170kN ± 8.89kN), ‘Control’ (171.8 ± 16.5kN) and ‘Slanted’ (173kN ± 21.9kN) groups, the ‘Scratched’ group showed slightly higher values (193kN ± 11.9kN). The Ti adapter sleeves were plastically deformed but did not fail catastrophically.

The present study suggests that manufacturer's recommendations for removal of a well fixed femoral stem could be narrowed down to the ‘Truncated’ condition. Even this might not be necessary since the fracture load is still substantially higher than the ASTM standard requires. Surgeons should consider to keep stems with larger taper damages as previously thought and spare the patient from stem revision. The greatest reservation regarding adapter sleeves is the introduction of the new metal-on-metal interface between stem and sleeve, which could possibly facilitate fretting-corrosion, which is presently one of the major concerns for modular junctions (3). Clinically such problems have not been reported yet. Ongoing FE-simulations are performed to investigate whether micromotions between stem and head taper are altered by the investigated damages.

Introduction

Ceramic ball heads are well known in hip arthroplasty for their superior tribology performance and high burst strength. To assess the ball head performance and the in-vivo fracture risk Pandorf et al 2008 examined the burst strength of BIOLOX®forte (pure aluminium oxide ceramic, CeramTec GmbH, Plochingen, Germany) ball heads on clean standard test tapers and contaminated test tapers. They found that fat tissue and scratches are reducing the burst strength to 40% and to 20% of the reference burst strength, respectively. The aim of this work is to investigate if BIOLOX®delta (alumina matrix ceramic, CeramTec GmbH, Plochingen, Germany) ball heads show a similar behaviour as BIOLOX®forte ball heads with respect to taper contamination.

Purpose

One of the drawbacks of cemented total hip arthroplasty (THA) is aseptic loosening after long period, major reason for which is bioinertness of PMMA bone cement. To improve longevity of THA, interface bioactive bone cement (IBBC) technique which is characterized with smearing hydroxyapatite (HA) granules just before cementation has been used in our institute.

Introduction:

Concerns remain regarding both the toughness of alumina, and stability of zirconia ceramics in total hip arthroplasty (THA). A zirconia-toughened alumina (ZTA) bearing has been introduced, in which yttria-stabilized, zirconia polycrystals are uniformly distributed in an alumina matrix. The goal is to combine the wear resistance of alumina with the toughness of zirconia. Zirconia's toughness is attributed to a tetragonal to monoclinic (t-m) phase transformation that occurs in response to a crack, hindering its propagation; however, it might decrease material stability. The purposes of this study were to investigate the degree and position of metal transfer, and the occurrence of t-m phase transformation using Raman spectroscopy, in a series of retrieved, ZTA femoral heads.

The RIPO register collects data of all primary and revision hip replacement surgeries performed in Region Emilia-Romagna, Italy since 1stJanuary 2000.

The present study is aimed to analyze the survival rate of patients with Biolox®delta and Biolox®forte components, (CeramTec, Plochingen Germany) considering possible confounding factors. Only patients living in the region are considered in analysis, to avoid the bias resulting from the ‘loss’ of non-resident patients. The analysis has been conducted only on uncemented THA and monoblock, double mobility cups as well as such with pre-assembled inserts were excluded. Therefore, the finally analyzed database consists of 30’617 cases; 13’323 Biolox®forte and 17’294 Biolox®delta heads, articulating against ceramic or PE.

Unadjusted survival analysis was calculated according to Kaplan Meier method; with prosthesis failure as end point, defined as the revision of any prosthetic component for any cause.

To avoid a possible bias, revision of the prosthesis due to breakage of modular necks of the stem have not been considered. The results are summarized in Table 1.

*survival at 6 yrs follow-up

After adjusting for age and gender it resulted that Biolox®delta - XLpoly and Biolox®forte – poly increase the risk of revision (HR 1.4 and 1.2) compared to Biolox®delta - Biolox®delta;

When only ceramic fractures are considered, we observed 1 fracture of a 36 mm Delta head (1/8’917 = 0.01%) and 38 fractures of 28 mm Forte heads. The 38 fractures occurred mainly in cer-cer coupling (35/3’537 implants= 1%) and occasionally in cer-poly couplings (3/4’246 implants = 0.07%).

Fracture or damage of the Biolox®delta insert occurred in 10 implants out of 14’260(0.07%), while it had a higher incidence in Forte inserts (36 casesout of 6’932 implants = 0.52%).

It can be concluded that the presence of a poly liner decrease the survival of the implant. Beside this Biolox®delta significantly improved the resistance to fracture of both head and insert.