Explore the vast range of titles available.

Exoskeletons and active prostheses promise to enhance human mobility, but few have succeeded. Optimizing device characteristics on the basis of measured human performance could lead to improved designs. We have developed a method for identifying the exoskeleton assistance that minimizes human energy cost during walking. Optimized torque patterns from an exoskeleton worn on one ankle reduced metabolic energy consumption by 24.2 ± 7.4% compared to no torque. The approach was effective with exoskeletons worn on one or both ankles, during a variety of walking conditions, during running, and when optimizing muscle activity. Finding a good generic assistance pattern, customizing it to individual needs, and helping users learn to take advantage of the device all contributed to improved economy. Optimization methods with these features can substantially improve performance.

ObjectiveThe aim of the study was to evaluate the incidence of peripheral inserted central catheter (PICC) tip malposition when the catheter is inserted under real-time ultrasound (RTUS) guidance when compared with conventional landmark (CL) technique in neonates. Additional objectives were to evaluate the PICC longevity and central line associated blood stream infections (CLABSI).Study designIn this randomised controlled trial, neonates were randomised to ‘RTUS’ (n = 40) or ‘CL’ (n = 40) groups. PICC tip was placed under ultrasound guidance in lower third of superior vena cava in the RTUS group. In ‘CL’ group, PICC was inserted as calculated by anatomical landmarks.ResultsThe birth weight (1286 (926, 1662) vs. 1061 (889, 1636) g) and gestation (31.12 (3.1) vs. 31.4 (3.6) wks) were comparable among the groups. RTUS guidance during PICC insertion reduced incidence of tip malposition by 52% (67.5 vs. 32.5%; RR: 0.48; 95% CI: 0.29–0.79). The longevity of PICC and episodes of CLABSI were however similar in the two groups.ConclusionsReal-time ultrasound guidance during PICC placement reduces the incidence of tip malposition.

Purpose Hearing aid fitting can be challenging when tinnitus accompanies hearing loss, as speech intelligibility and quality of life are affected by both hearing loss and tinnitus perception. However, studies focusing on the optimal hearing aid fitting for this group are scarce. Here, we aim to investigate the performance of alternative hearing aid fitting scenarios in improving hearing aid benefit and managing tinnitus. Methods Sixty-six participants were included in the study and randomly divided into three groups based on the fitting formula: NAL-NL2, DSL pediatric and hybrid gain fitting procedure (covering NAL-NL2 for low frequencies and DSL pediatric formulas for high frequencies). Hearing aid benefit was evaluated using the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire and speech perception in noise (SPIN). To evaluate tinnitus perception, psychoacoustic characteristics of tinnitus were determined, and the Tinnitus Handicap Inventory (THI) was gathered. Results The NAL-NL2 fitting procedure showed better results in hearing aid benefit and SPIN compared to the DSL pediatric procedure. In the DSL pediatric procedure, better results were obtained in tinnitus management compared to NAL-NL2. There was no difference between the hybrid fitting procedure and DSL pediatric in tinnitus management. The hybrid fitting procedure also did not differ from NAL-NL2 in SPIN and hearing aid benefit. Conclusion Here, we propose a hybrid gain fitting procedure that can be a better alternative to boost hearing aid performance and tinnitus management in clinical practice.

The number of total knee arthroplasty (TKA) procedures continuously increases, with good to excellent results. In the last few years, new surgical techniques have been developed to improve prosthesis positioning. In this context, patient-specific instrumentation is included. The goal of this study was to compare the perioperative parameters and the spatial positioning of prosthetic components in TKA procedures performed with patient-specific instrumentation vs traditional TKA. In this prospective comparative randomized study, 15 patients underwent TKA with 3-dimensional magnetic resonance imaging (MRI) preoperative planning (patient-specific instrumentation group) and 15 patients underwent traditional TKA (non–patient-specific instrumentation group). All patients underwent postoperative computed tomography (CT) examination. In the patient-specific instrumentation group, preoperative data planning regarding femoral and tibial bone resection was correlated with intraoperative measurements. Surgical time, length of hospitalization, and intraoperative and postoperative bleeding were compared between the 2 groups. Positioning of implants on postoperative CT was assessed for both groups. Data planned with 3-dimensional MRI regarding the depth of bone cuts showed good to excellent correlation with intraoperative measurements. The patient-specific instrumentation group showed better perioperative outcomes and good correlation between the spatial positioning of prosthetic components planned preoperatively and that seen on postoperative CT. Less variability was found in the patient-specific instrumentation group than in the non–patient-specific instrumentation group in spatial orientation of prosthetic components. Preoperative planning with 3-dimensional MRI in TKA has a better perioperative outcome compared with the traditional method. Use of patient-specific instrumentation can also improve the spatial positioning of both prosthetic components. [The number of total knee arthroplasty (TKA) procedures continuously increases, with good to excellent results. In the last few years, new surgical techniques have been developed to improve prosthesis positioning. In this context, patient-specific instrumentation is included. The goal of this study was to compare the perioperative parameters and the spatial positioning of prosthetic components in TKA procedures performed with patient-specific instrumentation vs traditional TKA. In this prospective comparative randomized study, 15 patients underwent TKA with 3-dimensional magnetic resonance imaging (MRI) preoperative planning (patient-specific instrumentation group) and 15 patients underwent traditional TKA (non–patient-specific instrumentation group). All patients underwent postoperative computed tomography (CT) examination. In the patient-specific instrumentation group, preoperative data planning regarding femoral and tibial bone resection was correlated with intraoperative measurements. Surgical time, length of hospitalization, and intraoperative and postoperative bleeding were compared between the 2 groups. Positioning of implants on postoperative CT was assessed for both groups. Data planned with 3-dimensional MRI regarding the depth of bone cuts showed good to excellent correlation with intraoperative measurements. The patient-specific instrumentation group showed better perioperative outcomes and good correlation between the spatial positioning of prosthetic components planned preoperatively and that seen on postoperative CT. Less variability was found in the patient-specific instrumentation group than in the non–patient-specific instrumentation group in spatial orientation of prosthetic components. Preoperative planning with 3-dimensional MRI in TKA has a better perioperative outcome compared with the traditional method. Use of patient-specific instrumentation can also improve the spatial positioning of both prosthetic components. [ Orthopedics. 2015; 38(4):e271–e280.]

Purpose Rising costs in healthcare for total hip arthroplasty (THA) mean that new solutions must be considered, such as the use of single-use ancillaries (SUA). The goal of this study was to assess the accuracy of 2D templating in primary THA for the use of reduced-size SUA. Our hypothesis was that the accuracy of 2D templating in primary THA would be higher than 95%, give or take two sizes. Method This single-centre prospective study included all primary THAs performed over two years. Templating was carried out using 2D templating on anteroposterior pelvic X-rays. The template sizes were compared to the implant sizes. The primary endpoint was the rate of coincidence between digitally templated estimates and the actual implant sizes. The secondary endpoint was the difference of accuracy based on patient parameters. Results We analysed 512 cases of THA. Accuracy within two sizes was 96.9% for acetabular implants and 98.5% for femoral implants. Accuracy was below the 95% threshold only in patients under 55 and over 85 years old. A BMI above 30.0 kg/m 2 significantly reduced accuracy but did not fall below the 95% threshold. The operated hip, the type of implant, and the operative indication did not significantly influence templating accuracy. Conclusion Using reduced-size SUA with five rasps and five reamers depending on template sizes means that THA can be performed in more than 95% of cases allowing the use of compact single use ancillaries.

Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous abrasion and repassivation process with a subsequent cold welding at the titanium alloy modular interface. Surface layers of 10 - 30 μm titanium oxide were observed. Surface cracks caused by fretting or fretting corrosion finally lead to fatigue fracture of the titanium alloy modular neck adapters. Neck adapters made of cobalt chrome alloy show significantly reduced micromotions especially in case of contaminated cone connection. With a cobalt-chromium neck the micromotions can be reduced by a factor of 3 compared to the titanium neck. The incidence of fretting corrosion was also substantially lower with the cobalt-chromium neck configuration. Conclusions Failure of modular titanium alloy neck adapters can be initiated by surface micromotions due to surface contamination or highly loaded implant components. In the present study, the patients at risk were men with an average weight over 100 kg. Modular cobalt chrome neck adapters provide higher safety compared to titanium alloy material.

Purpose. To preliminarily evaluate the feasibility and accuracy of using rapid prototyping drill templates (RPDTs) for C1 lateral mass screw (C1-LMS) and C2 pedicle screw (C2-PS) placement. Methods. 23 formalin-fixed craniocervical cadaver specimens were randomly divided into two groups. In the conventional method group, intraoperative fluoroscopy was used to assist the screw placement. In the RPDT navigation group, specific RPDTs were constructed for each specimen and were used intraoperatively for screw placement navigation. The screw position, the operating time, and the fluoroscopy time for each screw placement were compared between the 2 groups. Results. Compared with the conventional method, the RPDT technique significantly increased the placement accuracy of the C2-PS (p<0.05). In the axial plane, using RPDTs also significantly increased C1-LMS placement accuracy (p<0.05). In the sagittal plane, although using RPDTs had a very high accuracy rate (100%) in C1-LMS placement, it was not statistically significant compared with the conventional method (p>0.05). Moreover, the RPDT technique significantly decreased the operating and fluoroscopy times. Conclusion. Using RPDTs significantly increases the accuracy of C1-LMS and C2-PS placement while decreasing the screw placement time and the radiation exposure. Due to these advantages, this approach is worth promoting for use in the Harms technique.

Prosthetic alignment, positioning of a prosthetic foot relative to a socket, is an iterative process in which an amputee's gait is optimized through repetitive optical gait observation and induction of alignment adjustments when deviations are detected in spatiotemporal and kinematic gait parameters. An important limitation of the current prosthetic alignment approach is the subjectivity and the lack of standardized quantifiable baseline values. The purpose of this systematic review is to investigate if an optimal alignment criterion can be derived from published articles. Moreover, we investigated the effect of alignment changes on spatiotemporal, kinematic and kinetic gait parameters. A total of 11 studies were included, two controlled before-and-after studies and nine-interrupted time series studies. The results demonstrate that alignment changes have a predictable influence on the included kinetic parameters. However, the effect of alignment changes on spatio-temporal and kinematic gait parameters are generally unpredictable. These findings suggest that it is imperative to include kinetics in the process of dynamic prosthetic alignment. Partially this can be established by communication with the prosthetic user in terms of perceived socket comfort, but the use of measurement tools should also be considered. While current literature is not conclusive about an optimal alignment, future alignment research should focus on alignment optimisation based on kinetic outcomes.

Dental restorations are increasingly manufactured by CAD/CAM systems. Currently, there are two alternatives for digitizing dental implants: direct intra-oral data capturing or indirect from a master cast, both with transfer caps (scanbodies). The aim of this study was the evaluation of the fit of the scanbodies and their ability of reposition. At the site of the first molars and canines, implants were placed bilaterally in a polymer lower arch model (original model), and an impression was taken for fabricating a stone cast (stone model). Ten white-light scans were obtained from the original and the stone model with the scanbodies in place. The scanbodies were retrieved after each scan and re-attached to the same implant or lab analogue. The first scan of the series served as control in both groups. The subsequent nine scans and control were superimposed using inspection software to identify the discrepancies of the four scanbodies in both experimental groups. The systematic error of digitizing the models was 13 μm for the polymer and 5 μm for the stone model. The mean discrepancy of the scanbodies was 39 μm (±58 μm) on the original implants versus 11 μm (±17 μm) on the lab analogues. The difference in scanbody discrepancy between original implants and lab analogues was statistically significant ( p  < 0.05, Mann–Whitney U test). Scanbody discrepancy was higher on original implants than on lab analogues. Fit and reproducibility of the scanbodies on original implants should be improved to achieve higher accuracy of implant-supported CAD/CAM fabricated restorations.

Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial registration: Iranian Registry of Clinical Trials IRCT2013061813706N1.