Using speech for mode selection in control of multifunctional myoelectric prostheses.

PubMed

Fang, Peng; Wei, Zheng; Geng, Yanjuan; Yao, Fuan; Li, Guanglin

2013-01-01

Electromyogram (EMG) recorded from residual muscles of limbs is considered as suitable control information for motorized prostheses. However, in case of high-level amputations, the residual muscles are usually limited, which may not provide enough EMG for flexible control of myoelectric prostheses with multiple degrees of freedom of movements. Here, we proposed a control strategy, where the speech signals were used as additional information and combined with the EMG signals to realize more flexible control of multifunctional prostheses. By replacing the traditional "sequential mode-switching (joint-switching)", the speech signals were used to select a mode (joint) of the prosthetic arm, and then the EMG signals were applied to determine a motion class involved in the selected joint and to execute the motion. Preliminary results from three able-bodied subjects and one transhumeral amputee demonstrated the proposed strategy could achieve a high mode-selection rate and enhance the operation efficiency, suggesting the strategy may improve the control performance of commercial myoelectric prostheses.

Investigating the primary stability of the transversal support tibial plateau concept to retain both cruciate ligaments during total knee arthroplasty.

PubMed

Nowakowski, Andrej M; Stangel, Melanie; Grupp, Thomas M; Valderrabano, Victor

2012-09-27

The important roles of the anterior cruciate ligament regarding knee stability, physiologic kinematics, and proprioception are unquestioned. Thus, various efforts have been made to retain the ACL during total knee arthroplasty (TKA). Neither of the existing solutions to this problem, i.e. bicruciate retaining prostheses and implantation of two unicondylar prostheses, has been successful because of concept-specific problems as well as general difficulties with implant fixation. The new transversal support tibial plateau concept is a prosthesis of two individual joint surfaces reinforced beneath the articular line by joint surface supports and buttressed by a single transversal support. This configuration, which enables retention of both cruciate ligaments, should provide good bone fixation and ensure long-term alignment of the individual joint surfaces. In the current study, four prototypes based on this novel concept were developed and the resulting primary stability was analyzed using adapted load testing. The test set-up, with the model-loading of specially prepared Sawbones® and a sinusoidal oscillating load transmission with 25 000 cycles over 10 increasing load levels, achieved subsidence, which enabled comparison of the four different model variants regarding primary stability in view of bone anchoring. The model variant (TSmobile) that allowed transverse glide of the joint surface supports along the transversal support revealed the largest subsidence. A rigid attachment of the joint surface supports of the transversal support tibial plateau thus appears to offer increased primary stability regarding bone anchoring.

A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope.

PubMed

Shen, Yi; Li, Xiaomiao; Fu, Xiaodong; Wang, Weili

2015-11-01

Posterior tibial slope that is created during proximal tibial resection in total knee arthroplasty has emerged as an important factor in the mechanics of the knee joint and the surgical outcome. But the ideal degree of posterior tibial slope for recovery of the knee joint function and preventions of complications remains controversial and should vary in different racial groups. The objective of this paper is to investigate the effects of posterior tibial slope on contact stresses in the tibial polyethylene component of total knee prostheses. Three-dimensional finite element analysis was used to calculate contact stresses in tibial polyethylene component of total knee prostheses subjected to a compressive load. The 3D finite element model of total knee prosthesis was constructed from the images produced by 3D scanning technology. Stresses in tibial polyethylene component were calculated with four different posterior tibial slopes (0°, 3°, 6° and 9°). The 3D finite element model of total knee prosthesis we presented was well validated. We found that the stress distribution in the polythene as evaluated by the distributions of the von Mises stress, the maximum principle stress, the minimum principle stress and the Cpress were more uniform with 3° and 6° posterior tibial slopes than with 0° and 9° posterior tibial slopes. Moreover, the peaks of the above stresses and trends of changes with increasing degree of knee flexion were more ideal with 3° and 6° posterior slopes. The results suggested that the tibial component inclination might be favourable to 7°-10° so far as the stress distribution is concerned. The range of the tibial component inclination also can decrease the wear of polyethylene. Chinese posterior tibial slope is bigger than in the West, and the current domestic use of prostheses is imported from the West, so their demands to tilt back bone cutting can lead to shorten the service life of prostheses; this experiment result is of important clinical significance, guiding orthopaedic surgeon after the best angle to cut bone.

Evaluation of a commercial multiplex PCR (Unyvero i60®) designed for the diagnosis of bone and joint infections using prosthetic-joint sonication.

PubMed

Prieto-Borja, Laura; Rodriguez-Sevilla, Graciela; Auñon, Alvaro; Pérez-Jorge, Concepción; Sandoval, Enrique; Garcia-Cañete, Joaquín; Gadea, Ignacio; Fernandez-Roblas, Ricardo; Blanco, Antonio; Esteban, Jaime

2017-04-01

The development of sonication protocols over the last few years has improved the sensitivity of conventional cultures for the diagnosis of prosthetic-joint infection (PJI). However, the development of a new, specifically designed kit for the molecular diagnosis of PJI could provide a major improvement in this field. Prostheses retrieved from patients who underwent implant removal from May 2014 to May 2015 were sent for culture, and processed according to a previously defined protocol that included sonication. Furthermore, 180 microlitres of sonication fluid were used to carry out the multiplex PCR test (Unyvero i60 system ® ). A comparison of the sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, was performed. The study was approved by the Clinical Research Ethics Committee. The analysis included 88 prostheses from 68 patients (1.29 prostheses/patient). The type of prostheses studied were knee (n=55), total hip (n=26), partial hip (n=5), and shoulder (n=2). Twenty-nine patients were diagnosed with a PJI (15 delayed, 12 acute, and 2 haematogenous infections). In 24 cases, the result of the PCR was positive, all but 1 corresponding to patients with clinical criteria of PJI. Nine resistance mechanisms were detected from 5 samples. The Unyvero i60 system ® showed slightly better results than traditional culture in terms of specificity and PPV. The Unyvero i60 system ® may play a role in rapid diagnosis of PJI, due to its high specificity and PPV. However, despite these results, cultures have to be performed to detect organisms not detected by the system. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

The Influence of Artificial Cervical Disc Prosthesis Height on the Cervical Biomechanics: A Finite Element Study.

PubMed

Yuan, Wei; Zhang, Haiping; Zhou, Xiaoshu; Wu, Weidong; Zhu, Yue

2018-05-01

Artificial cervical disc replacement is expected to maintain normal cervical biomechanics. At present, the effect of the Prestige LP prosthesis height on cervical biomechanics has not been thoroughly studied. This finite element study of the cervical biomechanics aims to predict how the parameters, like range of motion (ROM), adjacent intradiscal pressure, facet joint force, and bone-implant interface stress, are affected by different heights of Prestige LP prostheses. The finite element model of intact cervical spine (C3-C7) was obtained from our previous study, and the model was altered to implant Prestige LP prostheses at the C5-C6 level. The effects of the height of 5, 6, and 7 mm prosthesis replacement on ROM, adjacent intradiscal pressure, facet joint force, as well as the distribution of bone-implant interface stress were examined. ROM, adjacent intradiscal pressure, and facet joint force increased with the prosthesis height, whereas ROM and facet joint force decreased at C5-C6. The maximal stress on the inferior surface of the prostheses was greater than that on the superior surface, and the stresses increased with the prosthesis height. The biomechanical changes were slightly affected by the height of 5 and 6 mm prostheses, but were strongly affected by the 7-mm prosthesis. An appropriate height of the Prestige LP prosthesis can preserve normal ROM, adjacent intradiscal pressure, and facet joint force. Prostheses with a height of ≥2 mm than normal can lead to marked changes in the cervical biomechanics and bone-implant interface stress. Copyright © 2018 Elsevier Inc. All rights reserved.

21 CFR 888.6 - Degree of constraint.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ORTHOPEDIC DEVICES General Provisions § 888.6 Degree of constraint. Certain joint prostheses provide more... affecting the safety and effectiveness of orthopedic prostheses. FDA is defining the following standard...

21 CFR 888.6 - Degree of constraint.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ORTHOPEDIC DEVICES General Provisions § 888.6 Degree of constraint. Certain joint prostheses provide more... affecting the safety and effectiveness of orthopedic prostheses. FDA is defining the following standard...

21 CFR 888.6 - Degree of constraint.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ORTHOPEDIC DEVICES General Provisions § 888.6 Degree of constraint. Certain joint prostheses provide more... affecting the safety and effectiveness of orthopedic prostheses. FDA is defining the following standard...

21 CFR 888.6 - Degree of constraint.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ORTHOPEDIC DEVICES General Provisions § 888.6 Degree of constraint. Certain joint prostheses provide more... affecting the safety and effectiveness of orthopedic prostheses. FDA is defining the following standard...

Evaluation of total alloplastic temporo-mandibular joint replacement with two different types of prostheses: A three-year prospective study

PubMed Central

Gonzalez-Perez-Somarriba, Borja; Centeno, Gabriel; Vallellano, Carpóforo; Montes-Carmona, Jose-Francisco

2016-01-01

Background Temporo-Mandibular Joint (TMJ) replacement has been used clinically for years. The objective of this study was to evaluate outcomes achieved in patients with two different categories of TMJ prostheses. Material and Methods All patients who had a TMJ replacement (TMJR) implanted during the study period from 2006 through 2012 were included in this 3-year prospective study. All procedures were performed using the Biomet Microfixation TMJ Replacement System, and all involved replacing both the skull base component (glenoid fossa) and the mandibular condyle. Results Fifty-seven patients (38 females and 19 males), involving 75 TMJs with severe disease requiring reconstruction (39 unilateral, 18 bilateral) were operated on consecutively, and 68 stock prostheses and 7 custom-made prostheses were implanted. The mean age at surgery was 52.6±11.5 years in the stock group and 51.8±11.7 years in the custom-made group. In the stock group, after three years of TMJR, results showed a reduction in pain intensity from 6.4±1.4 to 1.6±1.2 (p<0.001), and an improvement in jaw opening from 2.7±0.9 cm to 4.2±0.7 cm (p<0.001). In the custom-made group, after three years of TMJR, results showed a reduction in pain intensity from 6.0±1.6 to 2.2±0.4 (p<0.001), and an improvement in jaw opening from 1.5±0.5 cm to 4.3±0.6 cm (p<0.001). No statistically significant differences between two groups were detected. Conclusions The results of this three-year prospective study support the surgical placement of TMJ prostheses (stock prosthetic, and custom-made systems), and show that the approach is efficacious and safe, reduces pain, and improves maximum mouth opening movement, with few complications. As such, TMJR represents a viable technique and a stable long-term solution for cranio-mandibular reconstruction in patients with irreversible end-stage TMJ disease. Comparing stock and custom-made groups, no statistically significant differences were detected with respect to pain intensity reduction and maximum mouth opening improvement. Key words:Temporo-mandibular joint, temporo-mandibular joint replacement, prosthesis, biomaterials, biomedical engineering, computer-aided design and manufacturing. PMID:27475697

Movement quality of conventional prostheses and the DEKA Arm during everyday tasks

PubMed Central

Cowley, Jeffrey; Resnik, Linda; Wilken, Jason; Walters, Lisa Smurr; Gates, Deanna

2017-01-01

Background Conventional prosthetic devices fail to restore the function and characteristic movement quality of the upper limb. The DEKA Arm is a new, advanced prosthesis featuring a compound, powered wrist and multiple grip configurations. Objectives The purpose of this study was to determine if the DEKA Arm improved the movement quality of upper limb prosthesis users compared to conventional prostheses. Study design Case series. Methods Three people with transradial amputation completed tasks of daily life with their conventional prosthesis and with the DEKA Arm. A total of 10 healthy controls completed the same tasks. The trajectory of the wrist joint center was analyzed to determine how different prostheses affected movement duration, speed, smoothness, and curvature compared to patients’ own intact limbs and controls. Results Movement quality decreased with the DEKA Arm for two participants, and increased for the third. Prosthesis users made slower, less smooth, more curved movements with the prosthetic limb compared to the intact limb and controls, particularly when grasping and manipulating objects. Conclusion The effects of one month of training with the DEKA Arm on movement quality varied with participants’ skill and experience with conventional prostheses. Future studies should examine changes in movement quality after long-term use of advanced prostheses. PMID:26932980

Cancer risk among patients with finger and hand joint and temporo-mandibular joint prostheses in Denmark.

PubMed

Fryzek, J P; Mellemkjaer, L; McLaughlin, J K; Blot, W J; Olsen, J H

1999-05-31

The use of artificial joint implants has risen greatly over the past years. However, few investigations of the cancer risk associated with implants have been performed. We investigated cancer risk in patients with finger and hand joint and temporo-mandibular (TMJ) joint implants. A nationwide cohort in Denmark of patients with finger and hand joint prostheses (n = 858) or TMJ implants (n = 389) was followed from January 1, 1977, to December 31, 1995, to evaluate any potential cancer risks subsequent to receiving these implants. Standardized incidence ratios (SIRs) for all cancers were 1.0 (95% CI = 0.8-1.2) for the finger and hand joint cohort and 1.1 (95% CI = 0.8-1.7) for the TMJ cohort. A significant risk for non-Hodgkin's lymphoma was found in the finger and hand joint cohort (SIR = 3.8, 95% CI = 1.5-7.8). When the finger and hand joint cohort was stratified by diagnosis of rheumatoid arthritis, the excess risk was seen only in the group with rheumatoid arthritis. This is consistent with past studies, which have found an association between rheumatoid arthritis and non-Hodgkin's lymphoma. Our results provide evidence that the cancer risk for patients with finger and hand joint prostheses and TMJ implants is similar to that for the general population.

Materials testing protocol for small joint prostheses.

PubMed

Savory, K M; Hutchinson, D T; Bloebaum, R

1994-10-01

In this article, a protocol for the evaluation of new materials for small joint prostheses is introduced. The testing methods employed in the protocol were developed by reviewing reported clinical failure modes and conditions found in vivo. The methods developed quantitatively evaluates the fatigue, fatigue crack propagation, and wear resistance properties of materials. For this study, a silicone elastomer similar to Dow Corning Silastic HP100, a radiation stable polypropylene, and a copolymer of polypropylene and ethylene propylene-diene monomer (EPDM) are evaluated. None of the materials tested demonstrated the ideal properties that are sought in a self-hinging joint prostheses. The silicone elastomer had excellent wear properties; however, cracks quickly propagated, causing catastrophic failure when fatigued. Conversely, the copolymer showed excellent fatigue crack propagation resistance and less than favorable wear properties. The polypropylene did not perform well in any evaluation.

[Synovial fluid from aseptically failed total hip or knee arthroplasty is not toxic to osteoblasts].

PubMed

Gallo, J; Zdařilová, A; Rajnochová Svobodová, A; Ulrichová, J; Radová, L; Smižanský, M

2010-10-01

A failure of total hip or knee artroplasty is associated with an increased production of joint fluid. This contains wear particles and host cells and proteins, and is assumed to be involved in the pathogenesis of aseptic loosening and periprosthetic osteolysis. This study investigated the effect of synovial fluid from patients with aseptically failed joint prostheses on osteoblast cultures. Synovial fluid samples were obtained from patients with failed total joint prostheses (TJP; n=36) and from control patient groups (n = 16) involving cases without TJP and osteoarthritis, without TJP but with osteoarthritis, and with stable TJP. The samples were treated in the standard manner and then cultured with the SaOS-2 cell line which shows the characteristics and behaviour of osteoblasts. Each fluid sample was also examined for the content of proteins, cells and selected cytokines (IL-1ß, TNF-α, IL-6, RANKL and OPG detected by ELISA). We tested the hypothesis assuming that the fluids from failed joints would show higher cytotoxicity to osteoblast culture and we also expected higher levels of IL-1ß, TNF-α, IL-6, and RANKL in patients with TJP failure and/ or with more severe bone loss. The statistical methods used included the Kruskal-Wallis ANOVA and Mann-Whitney U test. The fluids from failed TJPs showed the highest RANKL and the lowest OPG levels resulting in the highest RANKL/OPG ratio. However, there was no evidence suggesting that the joint fluids from failed TJPs would be more toxic to osteoblast culture than the fluids from control groups. In addition, no correlation was found between the fluid levels of molecules promoting inflammation and osteoclastic activity and the extent of bone loss in the hip (in terms of Saleh's classification) or the knee (AORI classification). In fact, the fluids from failed TJPs had higher protein levels in comparison with the controls, but the difference was not significant. The finding of high RANKL levels and low OPG concentrations is in agreement with the theory of aseptic loosening and periprosthetic osteolysis. The other cytokines, particularly TNF-α and IL-1ß, were found in low levels. This can be explained by the stage of particle disease at which the samples were taken for ELISA analysis. It is probable that the level of signal molecules reflects osteolytic process activity and is therefore not constant. The reason for no correlation found between cytokine levels and the extent of bone loss may also lie in the use of therapeutic classifications of bone defects that is apparently less sensitive to the biological activity of aseptic loosening and/or periprosthetic osteolysis. Synovial fluids from failed total hip or knee joint prostheses are not toxic to osteoblast cultures. Cytotoxicity indicators and levels of pro-inflammatory and pro-osteoclastic cytokines (IL-1ß, TNF-α, IL-6, RANKL and OPG) do not correlate well with the extent of periprosthetic bone loss. Key words: total joint replacement, arthroplasty, aseptic loosening, periprosthetic osteolysis, joint fluid, SaOS-2 cell line, cytotoxicity, cytokines, RANKL, OPG.

Protocol for concomitant temporomandibular joint custom-fitted total joint reconstruction and orthognathic surgery utilizing computer-assisted surgical simulation.

PubMed

Movahed, Reza; Teschke, Marcus; Wolford, Larry M

2013-12-01

Clinicians who address temporomandibular joint (TMJ) pathology and dentofacial deformities surgically can perform the surgery in 1 stage or 2 separate stages. The 2-stage approach requires the patient to undergo 2 separate operations and anesthesia, significantly prolonging the overall treatment. However, performing concomitant TMJ and orthognathic surgery (CTOS) in these cases requires careful treatment planning and surgical proficiency in the 2 surgical areas. This article presents a new treatment protocol for the application of computer-assisted surgical simulation in CTOS cases requiring reconstruction with patient-fitted total joint prostheses. The traditional and new CTOS protocols are described and compared. The new CTOS protocol helps decrease the preoperative workup time and increase the accuracy of model surgery. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Tissue sparing surgery in knee reconstruction: unicompartmental (UKA), patellofemoral (PFA), UKA + PFA, bi-unicompartmental (Bi-UKA) arthroplasties

PubMed Central

Manzotti, A.; Montironi, F.; Pullen, C.

2008-01-01

Recently mini-invasive joint replacement has become one of the hottest topics in the orthopaedic world. However, these terms have been improperly misunderstood as a “key-hole” surgery where traditional components are implanted with shorter surgical approaches, with few benefits and several possible dangers. Small implants as unicompartmental knee prostheses, patellofemoral prostheses and bi-unicompartmental knee prostheses might represent real less invasive procedures: Tissue sparing surgery, the Italian way to minimally invasive surgery (MIS). According to their experience the authors go through this real tissue sparing surgery not limited only to a small incision, but where the surgeons can respect the physiological joint biomechanics. PMID:19384616

Development of friction and wear full-scale testing for TKR prostheses with reliable low cost apparatus

NASA Astrophysics Data System (ADS)

Suwandi, Agri; Soemardi, Tresna P.; Kiswanto, Gandjar; Kusumaningsih, Widjajalaksmi; I. Gusti Agung I. G., W.

2018-02-01

Prostheses products must undergo simulation and physical testing, before clinical testing. Finite element method is a preliminary simulation for in vivo test. The method visualizes the magnitude of the compressive force and the critical location of the Total Knee Replacement (TKR) prostheses design. In vitro testing is classified as physical testing for prostheses product. The test is conducted to evaluate the potential failure of the product and the characteristics of the prostheses TKR material. Friction and wear testing are part of the in vivo test. Motion of knee joints, which results in the phenomena of extension and deflection in the femoral and tibia insert, is represented by friction and wear testing. Friction and wear tests aim to obtain an approximate lifetime in normal and extreme load patterns as characterized by the shape of the friction surface area. The lifetime estimation requires friction and wear full-scale testing equipments for TKR prostheses products. These are necessary in obtaining initial data on potential product failures and characterizing of the material based on the ASTM F2724-08 standards. Based on the testing result and statistical analysis data, the average wear rate value per year is 2.19 × 10-3 mg/MC, with a 10 % safety limit of volume and 14,400 cycles times, for 15 hours moving nonstop then the prediction of wear life of the component tibia insert is ± 10 years.

Alloplastic total temporomandibular joint replacements: do they perform like natural joints? Prospective cohort study with a historical control.

PubMed

Wojczyńska, A; Leiggener, C S; Bredell, M; Ettlin, D A; Erni, S; Gallo, L M; Colombo, V

2016-10-01

The aim of this study was to qualitatively and quantitatively describe the biomechanics of existing total alloplastic reconstructions of temporomandibular joints (TMJ). Fifteen patients with unilateral or bilateral TMJ total joint replacements and 15 healthy controls were evaluated via dynamic stereometry technology. This non-invasive method combines three-dimensional imaging of the subject's anatomy with jaw tracking. It provides an insight into the patient's jaw joint movements in real time and provides a quantitative evaluation. The patients were also evaluated clinically for jaw opening, protrusive and laterotrusive movements, pain, interference with eating, and satisfaction with the joint replacements. The qualitative assessment revealed that condyles of bilateral total joint replacements displayed similar basic motion patterns to those of unilateral prostheses. Quantitatively, mandibular movements of artificial joints during opening, protrusion, and laterotrusion were all significantly shorter than those of controls. A significantly restricted mandibular range of motion in replaced joints was also observed clinically. Fifty-three percent of patients suffered from chronic pain at rest and 67% reported reduced chewing function. Nonetheless, patients declared a high level of satisfaction with the replacement. This study shows that in order to gain a comprehensive understanding of complex therapeutic measures, a multidisciplinary approach is needed. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

[Ankle arthrodesis with interposition graft as a salvage procedure after failed total ankle replacement].

PubMed

Schill, Stephan

2007-12-01

Restoration of painless function to the lower limb by ankle fusion after failure of total ankle arthroplasty. Loose total ankle replacement. Severe ankle destruction and axial deviation in rheumatoid patients. Severe osteoarthritis in the subtalar and ankle joints. Infected total ankle replacement. Severe arterial occlusive disease of the affected extremity. Transfibular approach to the subtalar and ankle joints. Osteotomy and resection of the distal fibula 7-8 cm proximal to the tip of the lateral malleolus. Removal of the prosthetic components, synovectomy, and revitalization of the remaining bone surface. Removal of any residual articular cartilage from the subtalar joint surfaces. Determination of the extent of bone loss and defect filling with horizontally or vertically placed tricortical and cancellous bone graft from the resected fibula and, if necessary, from the ipsilateral anterior iliac crest. Tibiotalocalcaneal arthrodesis by retrograde insertion of a retrograde locking nail. Wound closure in layers. Split below-knee cast. Mobilization with below-knee cast without weight bearing for 6 weeks. Dynamic locking of the intramedullary nail. Partial weight bearing with a walker up to 20 kg for an additional 6 weeks. Gradual increase in weight bearing in accordance with radiologic evidence of consolidation. Fitted orthopedic shoe with rocker-bottom sole, and made to measure insoles. From January 2003 to September 2006, 15 patients with infected ankle prosthesis loosening (six Thompson-Richards prostheses, eight S.T.A.R. prostheses, and one Salto prosthesis) were treated. All patients underwent tibiotalocalcaneal interposition arthrodesis with femoral nailing in retrograde technique. The average AOFAS (American Orthopaedic Foot and Ankle Society) Score was 57.9 points (35-81 points) postoperatively. One patient developed a nonunion and revision surgery will have to be performed. Another patient with delayed wound healing and skin necrosis needed plastic surgery.

Practical considerations for volumetric wear analysis of explanted hip arthroplasties.

PubMed

Langton, D J; Sidaginamale, R P; Holland, J P; Deehan, D; Joyce, T J; Nargol, A V F; Meek, R D; Lord, J K

2014-01-01

Wear debris released from bearing surfaces has been shown to provoke negative immune responses in the recipient. Excessive wear has been linked to early failure of prostheses. Analysis using coordinate measuring machines (CMMs) can provide estimates of total volumetric material loss of explanted prostheses and can help to understand device failure. The accuracy of volumetric testing has been debated, with some investigators stating that only protocols involving hundreds of thousands of measurement points are sufficient. We looked to examine this assumption and to apply the findings to the clinical arena. We examined the effects on the calculated material loss from a ceramic femoral head when different CMM scanning parameters were used. Calculated wear volumes were compared with gold standard gravimetric tests in a blinded study. Various scanning parameters including point pitch, maximum point to point distance, the number of scanning contours or the total number of points had no clinically relevant effect on volumetric wear calculations. Gravimetric testing showed that material loss can be calculated to provide clinically relevant degrees of accuracy. Prosthetic surfaces can be analysed accurately and rapidly with currently available technologies. Given these results, we believe that routine analysis of explanted hip components would be a feasible and logical extension to National Joint Registries. Cite this article: Bone Joint Res 2014;3:60-8.

Design and energetic evaluation of a prosthetic knee joint actuator with a lockable parallel spring.

PubMed

Geeroms, J; Flynn, L; Jimenez-Fabian, R; Vanderborght, B; Lefeber, D

2017-02-03

There are disadvantages to existing damping knee prostheses which cause an asymmetric gait and higher metabolic cost during level walking compared to non-amputees. Most existing active knee prostheses which could benefit the amputees use a significant amount of energy and require a considerable motor. In this work, a novel semi-active actuator with a lockable parallel spring for a prosthetic knee joint has been developed and tested. This actuator is able to provide an approximation of the behavior of a healthy knee during most of the gait cycle of level walking. This actuator is expanded with a series-elastic actuator to mimic the full gait cycle and enable its use in other functional tasks like stair climbing and sit-to-stance. The proposed novel actuator reduces the energy consumption for the same trajectory with respect to a compliant or directly-driven prosthetic active knee joint and improves the approximation of healthy knee behavior during level walking compared to passive or variable damping knee prostheses.

Do the radial head prosthesis components fit with the anatomical structures of the proximal radioulnar joint?

PubMed

Wegmann, Kilian; Hain, Moritz K; Ries, Christian; Neiss, Wolfram F; Müller, Lars P; Burkhart, Klaus J

2015-09-01

The fitting accuracy of radial head components has been investigated in the capitulo-radial joint, and reduced contact after prosthetic replacement of the radial head has been observed. The kinematics of the proximal radioulnar joint (PRUJ) are affected by radial head arthroplasty as well, but have not yet been investigated in this regard. The elbow joints of 60 upper extremities of formalin-fixed body donors were disarticulated to obtain a good view of the PRUJ. Each specimen was mounted on the examining table and radial head position in the native PRUJ was assessed in neutral position, full pronation, and full supination. Measurements were repeated after implantation of mono- and bi-polar prostheses. Analysis of the distribution of the joint contacts in the compartments showed significant differences after radial head replacement. In comparison to the native joint, after bipolar and monopolar radial head replacement, the physiological shift of the proximal radius was altered. The physiological shift of the joint contact of the radial head from anterior to posterior during forearm rotation that was found in the native joint in our cadaver model was not observed after prosthetic replacement. With higher conformity and physiological kinematic of radial head prostheses, possibly lower shear forces and lower contact pressures would be generated. The tested radial head prostheses do not replicate the physiological kinematics of the radial head. Further development in the prosthesis design has to be made. The meticulous reconstruction of the annular ligament seems to be of importance to increase joint contact.

Equally good fixation of cemented and uncemented cups in total trapeziometacarpal joint prostheses. A randomized clinical RSA study with 2-year follow-up.

PubMed

Hansen, Torben Baek; Stilling, Maiken

2013-02-01

Cup failure is a recognized problem in total trapeziometacarpal (TM) joint prostheses; it may be related to poor fixation, which can be revealed by radiostereometric analysis (RSA). We compared the early implant migration of cemented trapezium cups to that of uncemented screw cups. In a prospective, parallel-group, randomized patient-blinded clinical trial, we included 32 hands in 28 patients (5 males) with a mean age of 58 (40-77) years and with Eaton stage-2 or -3 osteoarthritis of the trapeziometacarpal joint. Patients were randomized to surgery with a cemented DLC all-polyethylene cup (C) (n = 16) or an uncemented hydroxyapatite-coated chrome-cobalt Elektra screw cup (UC) (n = 16). Uncemented cups were inserted without threading of the bone. Stereoradiographs for evaluation of cup migration (primary effect size) and DASH and pain scores were obtained during 2 years of follow-up. The 2-year total translation (TT) was similar (p = 0.2): 0.24 mm (SD 0.10) for the C (n = 11) and 0.19 mm (SD 0.16) for the UC (n = 11). Variances were similar (p = 0.4). Judged by RSA, 2 UC cups and 1 C cup became loose (TT > 1 mm). Both UC cups were found to be loose at revision. Grip strength, pain, and DASH scores were similar between groups at all measurement points. Early implant fixation and clinical outcome were equally good with both cup designs. This is the first clinical RSA study on trapezium cups, and the method appears to be clinically useful for detection of loose implants.

J-integral fracture toughness and tearing modulus measurement of radiation cross-linked UHMWPE.

PubMed

Gomoll, A; Wanich, T; Bellare, A

2002-11-01

Radiation and chemical cross-linking of medical grade ultrahigh molecular weight polyethylene (UHMWPE) has recently been utilized in an effort to improve wear performance of total joint replacement components. However, reductions in mechanical properties with cross-linking are cause for concern regarding the use of cross-linked UHMWPE for high-stress applications such as in total knee replacement prostheses. In this study, the fracture behavior of radiation cross-linked UHMWPE was compared to that of uncross-linked UHMWPE. The Rice and Sorensen model that utilizes mechanical parameters obtained from uniaxial tensile and compact tension tests was used to calculate the steady state J-integral fracture toughness, Jss, for radiation cross-linked UHMWPE. Jss decreased monotonically with increase in radiation dose. UHMWPE exhibited tough, ductile tearing behavior with stable crack growth when it was cross-linked using a gamma radiation dose of 0-50 kGy. However, in cross-linked UHMWPE irradiated to a dose of 100 and 200 kGy, unstable fracture occurred spontaneously upon attaining the initial crack driving force, J1c. This indicates that a high degree of cross-linking is less desirable for high-stress applications in orthopaedic implants. However, a substantial increase in J1c, even at a low degree of cross-linking, suggests that a low degree of cross-linking may be beneficial for resistance to delamination and catastrophic failure, both of which require an initiation step for the fracture to propagate in the material. This mechanical test should, however, be considered along with fatigue tests and joint simulator testing before determination of an appropriate amount of cross-linking for total joint replacement prostheses that experience high stresses.

Biomechanical study of the tibia in knee replacement revision.

PubMed

Quílez, M P; Pérez, M A; Seral-García, B

2015-01-01

The best management of severe bone defects following total knee replacement is still controversial. Metal augments, tantalum cones and porous tibial sleeves could help the surgeon to manage any type of bone loss, providing a stable and durable knee joint reconstruction. Five different types of prostheses have been analysed: one prosthesis with straight stem; two prostheses with offset stem, with and without supplement, and two prostheses with sleeves, with and without stem. The purpose of this study is to report a finite element study of revision knee tibial implants. The main objective was to analyse the tibial bone density changes and Von Misses tension changes following different tibial implant designs. In all cases, the bone density decreases in the proximal epiphysis and medullary channels, with a bone density increase also being predicted in the diaphysis and at the bone around the stems tips. The highest value of Von Misses stress has been obtained for the straight tibial stem, and the lowest for the stemless metaphyseal sleeves prosthesis. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

Finite Element Analysis of Influence of Axial Position of Center of Rotation of a Cervical Total Disc Replacement on Biomechanical Parameters: Simulated 2-Level Replacement Based on a Validated Model.

PubMed

Li, Yang; Zhang, Zhenjun; Liao, Zhenhua; Mo, Zhongjun; Liu, Weiqiang

2017-10-01

Finite element models have been widely used to predict biomechanical parameters of the cervical spine. Previous studies investigated the influence of position of rotational centers of prostheses on cervical biomechanical parameters after 1-level total disc replacement. The purpose of this study was to explore the effects of axial position of rotational centers of prostheses on cervical biomechanics after 2-level total disc replacement. A validated finite element model of C3-C7 segments and 2 prostheses, including the rotational center located at the superior endplate (SE) and inferior endplate (IE), was developed. Four total disc replacement models were used: 1) IE inserted at C4-C5 disc space and IE inserted at C5-C6 disc space (IE-IE), 2) IE-SE, 3) SE-IE, and 4) SE-SE. All models were subjected to displacement control combined with a 50 N follower load to simulate flexion and extension motions in the sagittal plane. For each case, biomechanical parameters, including predicted moments, range of rotation at each level, facet joint stress, and von Mises stress on the ultra-high-molecular-weight polyethylene core of the prostheses, were calculated. The SE-IE model resulted in significantly lower stress at the cartilage level during extension and at the ultra-high-molecular-weight polyethylene cores when compared with the SE-SE construct and did not generate hypermotion at the C4-C5 level compared with the IE-SE and IE-IE constructs. Based on the present analysis, the SE-IE construct is recommended for treating cervical disease at the C4-C6 level. This study may provide a useful model to inform clinical operations. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of total alloplastic temporo-mandibular joint replacement with two different types of prostheses: A three-year prospective study.

PubMed

Gonzalez-Perez, L-M; Gonzalez-Perez-Somarriba, B; Centeno, G; Vallellano, C; Montes-Carmona, J-F

2016-11-01

Temporo-Mandibular Joint (TMJ) replacement has been used clinically for years. The objective of this study was to evaluate outcomes achieved in patients with two different categories of TMJ prostheses. All patients who had a TMJ replacement (TMJR) implanted during the study period from 2006 through 2012 were included in this 3-year prospective study. All procedures were performed using the Biomet Microfixation TMJ Replacement System, and all involved replacing both the skull base component (glenoid fossa) and the mandibular condyle. Fifty-seven patients (38 females and 19 males), involving 75 TMJs with severe disease requiring reconstruction (39 unilateral, 18 bilateral) were operated on consecutively, and 68 stock prostheses and 7 custom-made prostheses were implanted. The mean age at surgery was 52.6±11.5 years in the stock group and 51.8±11.7 years in the custom-made group. In the stock group, after three years of TMJR, results showed a reduction in pain intensity from 6.4±1.4 to 1.6±1.2 (p<0.001), and an improvement in jaw opening from 2.7±0.9 cm to 4.2±0.7 cm (p<0.001). In the custom-made group, after three years of TMJR, results showed a reduction in pain intensity from 6.0±1.6 to 2.2±0.4 (p<0.001), and an improvement in jaw opening from 1.5±0.5 cm to 4.3±0.6 cm (p<0.001). No statistically significant differences between two groups were detected. The results of this three-year prospective study support the surgical placement of TMJ prostheses (stock prosthetic, and custom-made systems), and show that the approach is efficacious and safe, reduces pain, and improves maximum mouth opening movement, with few complications. As such, TMJR represents a viable technique and a stable long-term solution for cranio-mandibular reconstruction in patients with irreversible end-stage TMJ disease. Comparing stock and custom-made groups, no statistically significant differences were detected with respect to pain intensity reduction and maximum mouth opening improvement.

21 CFR 888.5 - Resurfacing technique.

Code of Federal Regulations, 2014 CFR

2014-04-01

... techniques, certain joint prostheses require far less bone resection than other devices intended to repair or replace the same joint. The amount of bone resection may or may not affect the safety and effectiveness of...

21 CFR 888.5 - Resurfacing technique.

Code of Federal Regulations, 2011 CFR

2011-04-01

... techniques, certain joint prostheses require far less bone resection than other devices intended to repair or replace the same joint. The amount of bone resection may or may not affect the safety and effectiveness of...

21 CFR 888.5 - Resurfacing technique.

Code of Federal Regulations, 2013 CFR

2013-04-01

... techniques, certain joint prostheses require far less bone resection than other devices intended to repair or replace the same joint. The amount of bone resection may or may not affect the safety and effectiveness of...

21 CFR 888.5 - Resurfacing technique.

Code of Federal Regulations, 2010 CFR

2010-04-01

... techniques, certain joint prostheses require far less bone resection than other devices intended to repair or replace the same joint. The amount of bone resection may or may not affect the safety and effectiveness of...

21 CFR 888.5 - Resurfacing technique.

Code of Federal Regulations, 2012 CFR

2012-04-01

... techniques, certain joint prostheses require far less bone resection than other devices intended to repair or replace the same joint. The amount of bone resection may or may not affect the safety and effectiveness of...

Practical considerations for volumetric wear analysis of explanted hip arthroplasties

PubMed Central

Langton, D. J.; Sidaginamale, R. P.; Holland, J. P.; Deehan, D.; Joyce, T. J.; Nargol, A. V. F.; Meek, R. D.; Lord, J. K.

2014-01-01

Objectives Wear debris released from bearing surfaces has been shown to provoke negative immune responses in the recipient. Excessive wear has been linked to early failure of prostheses. Analysis using coordinate measuring machines (CMMs) can provide estimates of total volumetric material loss of explanted prostheses and can help to understand device failure. The accuracy of volumetric testing has been debated, with some investigators stating that only protocols involving hundreds of thousands of measurement points are sufficient. We looked to examine this assumption and to apply the findings to the clinical arena. Methods We examined the effects on the calculated material loss from a ceramic femoral head when different CMM scanning parameters were used. Calculated wear volumes were compared with gold standard gravimetric tests in a blinded study. Results Various scanning parameters including point pitch, maximum point to point distance, the number of scanning contours or the total number of points had no clinically relevant effect on volumetric wear calculations. Gravimetric testing showed that material loss can be calculated to provide clinically relevant degrees of accuracy. Conclusions Prosthetic surfaces can be analysed accurately and rapidly with currently available technologies. Given these results, we believe that routine analysis of explanted hip components would be a feasible and logical extension to National Joint Registries. Cite this article: Bone Joint Res 2014;3:60–8. PMID:24627327

Biomechanics principle of elbow joint for transhumeral prostheses: comparison of normal hand, body-powered, myoelectric & air splint prostheses.

PubMed

Abd Razak, Nasrul Anuar; Abu Osman, Noor Azuan; Gholizadeh, Hossein; Ali, Sadeeq

2014-09-10

Understanding of kinematics force applied at the elbow is important in many fields, including biomechanics, biomedical engineering and rehabilitation. This paper provides a comparison of a mathematical model of elbow joint using three different types of prosthetics for transhumeral user, and characterizes the forces required to overcome the passive mechanical of the prosthetics at the residual limb. The study modeled the elbow as a universal joint with intersecting axes of x-axis and y-axis in a plain of upper arm and lower arm. The equations of force applied, torque, weight and length of different type of prosthetics and the anthropometry of prosthetics hand are discussed in this study. The study also compares the force, torque and pressure while using all three types of prosthetics with the normal hand. The result was measured from the elbow kinematics of seven amputees, using three different types of prosthetics. The F-Scan sensor used in the study is to determine the pressure applied at the residual limb while wearing different type of prostheses. These technological advances in assessment the biomechanics of an elbow joint for three different type of prosthetics with the normal hand bring the new information for the amputees and prosthetist to choose the most suitable device to be worn daily.

In vitro assessment of the contact mechanics of reverse-engineered distal humeral hemiarthroplasty prostheses.

PubMed

Willing, Ryan; Lapner, Michael; King, Graham J W; Johnson, James A

2014-11-01

Distal humeral hemiarthroplasty alters cartilage contact mechanics, which may predispose to osteoarthritis. Current prostheses do not replicate the native anatomy, and therefore contribute to these changes. We hypothesized that prostheses reverse-engineered from the native bone shape would provide similar contact patterns as the native articulation. Reverse-engineered hemiarthroplasty prostheses were manufactured for five cadaveric elbows based on CT images of the distal humerus. Passive flexion trials with constant muscle forces were performed with the native articulation intact while bone motions were recorded using a motion tracking system. Motion trials were then repeated after the distal humerus was replaced with a corresponding reverse-engineered prosthesis. Contact areas and patterns were reconstructed using computer models created from CT scan images combined with the motion tracker data. The total contact areas, as well as the contact area within smaller sub-regions of the ulna and radius, were analyzed for changes resulting from hemiarthroplasty using repeated-measures ANOVAs. Contact area at the ulna and radius decreased on average 42% (SD 19%, P=.008) and 41% (SD 42%, P=.096), respectively. Contact area decreases were not uniform throughout the different sub-regions, suggesting that contact patterns were also altered. Reverse-engineered prostheses did not reproduce the same contact pattern as the native joints, possibly because the thickness of the distal humerus cartilage layer was neglected when generating the prosthesis shapes or as a consequence of the increased stiffness of the metallic implants. Alternative design strategies and materials for hemiarthroplasty should be considered in future work. Copyright © 2014 Elsevier Ltd. All rights reserved.

Long-term stress distribution patterns of the ankle joint in varus knee alignment assessed by computed tomography osteoabsorptiometry.

PubMed

Onodera, Tomohiro; Majima, Tokifumi; Iwasaki, Norimasa; Kamishima, Tamotsu; Kasahara, Yasuhiko; Minami, Akio

2012-09-01

The stress distribution of an ankle under various physiological conditions is important for long-term survival of total ankle arthroplasty. The aim of this study was to measure subchondral bone density across the distal tibial joint surface in patients with malalignment/instability of the lower limb. We evaluated subchondral bone density across the distal tibial joint in patients with malalignment/instability of the knee by computed tomography (CT) osteoabsorptiometry from ten ankles as controls and from 27 ankles with varus deformity/instability of the knee. The quantitative analysis focused on the location of the high-density area at the articular surface, to determine the resultant long-term stress on the ankle joint. The area of maximum density of subchondral bone was located in the medial part in all subjects. The pattern of maximum density in the anterolateral area showed stepwise increases with the development of varus deformity/instability of the knee. Our results should prove helpful for designing new prostheses and determining clinical indications for total ankle arthroplasty.

A Powered Prosthetic Intervention for Bilateral Transfemoral Amputees

PubMed Central

Lawson, Brian E.; Ruhe, Brian; Shultz, Amanda; Goldfarb, Michael

2014-01-01

This paper presents the design and validation of a control system for a pair of powered knee and ankle prostheses to be used as a prosthetic intervention for bilateral transfemoral amputees. The control system leverages communication between the prostheses for enhanced awareness and stability, along with power generation at the knee and ankle joints to better restore biomechanical functionality in level ground walking. The control methodology employed is a combination of an impedance-based framework for weight-bearing portions of gait and a trajectory-based approach for the non-weight-bearing portions. The control system was implemented on a pair of self-contained powered knee and ankle prostheses, and the ability of the prostheses and control approach to provide walking functionality was assessed in a set of experimental trials with a bilateral transfemoral amputee subject. Specifically, experimental data from these trials indicate that the powered prostheses and bilateral control architecture provide gait kinematics that reproduce healthy gait kinematics to a greater extent than the subject’s daily-use passive prostheses. PMID:25014950

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

Prosthetic knee design by simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollerbach, K; Hollister, A

1999-07-30

Although 150,000 total knee replacement surgeries are performed annually in North America, current designs of knee prostheses have mechanical problems that include a limited range of motion, abnormal gait patterns, patellofemoral joint dysfunction, implant loosening or subsidence, and excessive wear. These problems fall into three categories: failure to reproduce normal joint kinematics, which results in altered limb function; bone-implant interface failure; and material failure. Modern computer technology can be used to design, prototype, and test new total knee implants. The design team uses the full range of CAD-CAM to design and produce implant prototypes for mechanical and clinical testing. Closermore » approximation of natural knee kinematics and kinetics is essential for improved patient function and diminished implant loads. Current knee replacement designs are based on 19th Century theories that the knee moves about a variable axis of rotation. Recent research has shown, however, that knee motion occurs about two fixed, offset axes of rotation. These aces are not perpendicular to the long axes of the bones or to each other, and the axes do not intersect. Bearing surfaces of mechanisms that move about axes of rotation are surfaces of revolution of those axes which advanced CAD technology can produce. Solids with surfaces of revolution for the two axes of rotation for the knee have been made using an HP9000 workstation and Structural Ideas Master Series CAD software at ArthroMotion. The implant's CAD model should closely replicate movements of the normal knee. The knee model will have a range of flexion-extension (FE) from -5 to 120 degrees. Movements include varus, valgus, internal and external rotation, as well as flexion and extension. The patellofemoral joint is aligned perpendicular to the FE axis and replicates the natural joint more closely than those of existing prostheses. The bearing surfaces will be more congruent than current designs and should generate lower stresses in the materials.« less

On occlusal forces in dentitions with implant-supported fixed cantilever prostheses.

PubMed

Falk, H

1990-01-01

The main aims of this thesis were (1) to study the functional characteristics of dentitions with mandibular implant-supported fixed cantilever prostheses - IFCP s- occluding with complete dentures, (2) to study in detail the magnitudes and distributions of axially directed closing and chewing forces in such dentitions, (3) to study the influence of number and distribution of occlusal contacts on the magnitude and distribution of closing and chewing forces, (4) to assess the vertical bending moment and the resulting vertical bending stress in the cantilever joints and (5) to find out whether the force distribution over the cantilever beams and the resulting vertical bending stress in the cantilever joint are influenced by the type of prosthetic construction in the opposing jaw. Closing and chewing forces were registered in altogether seventeen subjects by means of miniature strain gauge transducers mounted bilaterally and symmetrically in performed matrices in prosthetic appliances. Four, six or eight transducers, evenly distributed over the tooth-arch, permitted registrations of axially directed occlusal forces in several occluding areas simultaneously. In Papers I-IV, the implant-supported prostheses were installed in the mandible and occluded with complete dentures. In Paper V, group A, the fixture-supported prostheses were installed in the maxilla and occluded with tooth-supported fixed partial dentures whereas in group B, the arrangements were analogous to those in Papers I-IV. All subjects exhibited a rhythmic chewing pattern and preferred one side for chewing although both sides were used. Most chewing sequences were terminated with swallowing with occlusal force development. The mean total forces acting over the tooth-arch varied somewhat between groups and occlusal arrangements but averaged 350 and 170 N for closing and chewing respectively. Closing and chewing forces increased distally along the cantilever beams when occluding with complete dentures and decreased distally when occluding with fixed partial dentures. The distally increasing force distribution pattern could be altered to a distally decreasing force distribution pattern by infraoccluding the second cantilever unit by as little as 100 microns. Calculated vertical bending moments and stresses in the cantilever joints of the preferred chewing sides created by closing and chewing forces were larger in dentitions where the IFCP occluded with a complete denture than in dentitions where the IFCP occluded with a tooth-supported fixed partial denture.

The impact of surface and geometry on coefficient of friction of artificial hip joints.

PubMed

Choudhury, Dipankar; Vrbka, Martin; Mamat, Azuddin Bin; Stavness, Ian; Roy, Chanchal K; Mootanah, Rajshree; Krupka, Ivan

2017-08-01

Coefficient of friction (COF) tests were conducted on 28-mm and 36-mm-diameter hip joint prostheses for four different material combinations, with or without the presence of Ultra High Molecular Weight Polyethylene (UHMWPE) particles using a novel pendulum hip simulator. The effects of three micro dimpled arrays on femoral head against a polyethylene and a metallic cup were also investigated. Clearance played a vital role in the COF of ceramic on polyethylene and ceramic on ceramic artificial hip joints. Micro dimpled metallic femoral heads yielded higher COF against a polyethylene cup; however, with metal on metal prostheses the dimpled arrays significantly reduced the COF. In situ images revealed evidence that the dimple arrays enhanced film formation, which was the main mechanism that contributed to reduced friction. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro method for assessing the biomechanics of the patellofemoral joint following total knee arthroplasty.

PubMed

Coles, L G; Gheduzzi, S; Miles, A W

2014-12-01

The patellofemoral joint is a common site of pain and failure following total knee arthroplasty. A contributory factor may be adverse patellofemoral biomechanics. Cadaveric investigations are commonly used to assess the biomechanics of the joint, but are associated with high inter-specimen variability and often cannot be carried out at physiological levels of loading. This study aimed to evaluate the suitability of a novel knee simulator for investigating patellofemoral joint biomechanics. This simulator specifically facilitated the extended assessment of patellofemoral joint biomechanics under physiological levels of loading. The simulator allowed the knee to move in 6 degrees of freedom under quadriceps actuation and included a simulation of the action of the hamstrings. Prostheses were implanted on synthetic bones and key soft tissues were modelled with a synthetic analogue. In order to evaluate the physiological relevance and repeatability of the simulator, measurements were made of the quadriceps force and the force, contact area and pressure within the patellofemoral joint using load cells, pressure-sensitive film, and a flexible pressure sensor. The results were in agreement with those previously reported in the literature, confirming that the simulator is able to provide a realistic physiological loading situation. Under physiological loading, average standard deviations of force and area measurements were substantially lower and comparable to those reported in previous cadaveric studies, respectively. The simulator replicates the physiological environment and has been demonstrated to allow the initial investigation of factors affecting patellofemoral biomechanics following total knee arthroplasty. © IMechE 2014.

Rapid Prototyping for In Vitro Knee Rig Investigations of Prosthetized Knee Biomechanics: Comparison with Cobalt-Chromium Alloy Implant Material

PubMed Central

Schröder, Christian; Steinbrück, Arnd; Müller, Tatjana; Woiczinski, Matthias; Chevalier, Yan; Müller, Peter E.; Jansson, Volkmar

2015-01-01

Retropatellar complications after total knee arthroplasty (TKA) such as anterior knee pain and subluxations might be related to altered patellofemoral biomechanics, in particular to trochlear design and femorotibial joint positioning. A method was developed to test femorotibial and patellofemoral joint modifications separately with 3D-rapid prototyped components for in vitro tests, but material differences may further influence results. This pilot study aims at validating the use of prostheses made of photopolymerized rapid prototype material (RPM) by measuring the sliding friction with a ring-on-disc setup as well as knee kinematics and retropatellar pressure on a knee rig. Cobalt-chromium alloy (standard prosthesis material, SPM) prostheses served as validation standard. Friction coefficients between these materials and polytetrafluoroethylene (PTFE) were additionally tested as this latter material is commonly used to protect pressure sensors in experiments. No statistical differences were found between friction coefficients of both materials to PTFE. UHMWPE shows higher friction coefficient at low axial loads for RPM, a difference that disappears at higher load. No measurable statistical differences were found in knee kinematics and retropatellar pressure distribution. This suggests that using polymer prototypes may be a valid alternative to original components for in vitro TKA studies and future investigations on knee biomechanics. PMID:25879019

Is there a need for routine follow-up after primary total hip arthroplasty?

PubMed

Hacking, Craig; Weinrauch, Patrick; Whitehouse, Sarah L; Crawford, Ross W; Donnelly, William J

2010-10-01

The objective of routine outpatient assessment of well-functioning patients after primary total hip arthroplasty (THA) is to detect asymptomatic failure of prostheses to guide recommendations for early intervention. We have observed that the revision of THAs in asymptomatic patients is highly uncommon. We therefore question the need for routine follow-up of patients after THA. A prospective analysis of an orthopaedic database identified 158 patients who received 177 revision THAs over a four-year period. A retrospective chart review was conducted. Patient demographics, primary and revision surgery parameters and follow-up information were recorded and cross-referenced with Australian Orthopaedic Association National Joint Replacement Registry data. One hundred ten THAs in 104 patients (average age 70.4 (SD 9.8 years)). There were 70 (63.6%) in total, 13 (11.8%) femoral and 27 (24.5%) acetabular revisions. The indications for revision were aseptic loosening (70%), dislocation (8.2%), peri-prosthetic fracture (7.3%), osteolysis (6.4%) and infection (4.5%). Only four (3.6%) were asymptomatic revisions. A mean of 5.3 (SD 5.2 and 1.9 (SD 5.3)) follow-up appointments were required before revision in patients with and without symptoms, respectively. The average time from the primary to revision surgery was 11.8 (SD 7.23) years. We conclude that patients with prostheses with excellent long-term clinical results as validated by joint registries, routine follow-up of asymptomatic THA should be questioned and requires further investigation. Based on the work of this study, the current practice of routine follow-up of asymptomatic THA may be excessively costly and unnecessary, and a less resource-intensive review method may be more appropriate. © 2010 The Authors. ANZ Journal of Surgery © 2010 Royal Australasian College of Surgeons.

Wear simulation of total knee prostheses using load and kinematics waveforms from stair climbing.

PubMed

Abdel-Jaber, Sami; Belvedere, Claudio; Leardini, Alberto; Affatato, Saverio

2015-11-05

Knee wear simulators are meant to perform load cycles on knee implants under physiological conditions, matching exactly, if possible, those experienced at the replaced joint during daily living activities. Unfortunately, only conditions of low demanding level walking, specified in ISO-14243, are used conventionally during such tests. A recent study has provided a consistent knee kinematic and load data-set measured during stair climbing in patients implanted with a specific modern total knee prosthesis design. In the present study, wear simulation tests were performed for the first time using this data-set on the same prosthesis design. It was hypothesised that more demanding tasks would result in wear rates that differ from those observed in retrievals. Four prostheses for total knee arthroplasty were tested using a displacement-controlled knee wear simulator for two million cycles at 1.1 Hz, under kinematics and load conditions typical of stair climbing. After simulation, the corresponding damage scars on the bearings were qualified and compared with equivalent explanted prostheses. An average mass loss of 20.2±1.5 mg was found. Scanning digital microscopy revealed similar features, though the explant had a greater variety of damage modes, including a high prevalence of adhesive wear damage and burnishing in the overall articulating surface. This study confirmed that the results from wear simulation machines are strongly affected by kinematics and loads applied during simulations. Based on the present results for the full understanding of the current clinical failure of knee implants, a more comprehensive series of conditions are necessary for equivalent simulations in vitro. Copyright © 2015 Elsevier Ltd. All rights reserved.

Surgical treatment of tracheal collapse using pliable total ring prostheses: results in one experimental and 4 clinical cases.

PubMed Central

Ayres, S A; Holmberg, D L

1999-01-01

Pliable total ring prostheses were created from the polyvinyl chloride drip chambers of intravenous administration sets. The total ring prostheses were placed in one clinically normal research dog and in 4 client-owned dogs diagnosed with tracheal collapse. The research dog was euthanized one month after placement of the prostheses. Histopathological analysis of the trachea adjacent to the prostheses revealed a mild inflammatory response. The follow-up period for the clinical cases was from 4 months to 11 years. Radiographs taken and fluoroscopy performed 1 day to 5 months after surgery revealed improvement or resolution of the tracheal collapse. One dog was asymptomatic 28 weeks following surgery. Two dogs died 7 and 9 years after surgery, with one requiring intermittent medical management for coughing. They were euthanized for nonrespiratory illness. One dog had a persistent nonproductive cough, due to collapse of the mainstem bronchi, when last evaluated 4 months postoperatively. Pliable total ring prostheses provided adequate stability to the trachea and had the advantage of conforming to the trachea and being easy to create, place, and suture. Images Figure 1. Figure 2. PMID:10563237

The effect of adhesive strength of hydroxyapatite coating on the stability of hydroxyapatite-coated prostheses in vivo at the early stage of implantation

PubMed Central

Duan, Yonghong; Zhu, Shu; Guo, Fei; Zhu, Jinyu; Li, Mao; Ma, Jie

2012-01-01

Introduction With the increase in joint revision surgery after arthroplasty, defects of hydroxyapatite (HA)-coated prostheses have been observed increasingly often. These defects adversely affect the prosthetic stability in vivo. This study has analyzed the potential effect of the adhesive strength of HA coating on the stability of HA-coated prostheses in vivo after its implantation. Material and methods Sixty experimental rabbits were divided into HA- and Ti-coated groups. HA-coated prostheses were implanted into the bilateral epicondyle of rabbits femurs. Ti-coated prostheses were implanted as control. At different time points(4, 9, and 15 weeks) after implantation, bone tissue samples were fetched out respectively for histomorphometric analysis. Push-out testing was used to detect the ultimate shear strength at the bone-prosthesis interface. Scanning electron microscope (SEM) observation and energy-dispersive X-ray spectroscopy (EDX) analysis were used to observe the changes in surface composition of the prostheses after the ultimate shear strength testing. The coating adhesive strength of two kinds of coatings were also examined by scratch testing. Results Hydroxyapatite coating has an obvious advantage in facilitating osteogenesis and its plays a critical role in the stability of prostheses. However, the ultimate shear strength of HA-coated prostheses is much lower than that of Ti-coated implants (p < 0.01). Further study has demonstrated that the stability of HA-coated prostheses in vivo is affected by the relatively low adhesive strength between coating and substrate. Conclusions Obvious advantage in facilitating osteogenesis around HA-coated prostheses is not the only factor that determines the stability of prostheses in vivo. PMID:22661990

The accuracy and precision of radiostereometric analysis in upper limb arthroplasty.

PubMed

Ten Brinke, Bart; Beumer, Annechien; Koenraadt, Koen L M; Eygendaal, Denise; Kraan, Gerald A; Mathijssen, Nina M C

2017-06-01

Background and purpose - Radiostereometric analysis (RSA) is an accurate method for measurement of early migration of implants. Since a relation has been shown between early migration and future loosening of total knee and hip prostheses, RSA plays an important role in the development and evaluation of prostheses. However, there have been few RSA studies of the upper limb, and the value of RSA of the upper limb is not yet clear. We therefore performed a systematic review to investigate the accuracy and precision of RSA of the upper limb. Patients and methods - PRISMA guidelines were followed and the protocol for this review was published online at PROSPERO under registration number CRD42016042014. A systematic search of the literature was performed in the databases Embase, Medline, Cochrane, Web of Science, Scopus, Cinahl, and Google Scholar on April 25, 2015 based on the keywords radiostereometric analysis, shoulder prosthesis, elbow prosthesis, wrist prosthesis, trapeziometacarpal joint prosthesis, humerus, ulna, radius, carpus. Articles concerning RSA for the analysis of early migration of prostheses of the upper limb were included. Quality assessment was performed using the MINORS score, Downs and Black checklist, and the ISO RSA Results - 23 studies were included. Precision values were in the 0.06-0.88 mm and 0.05-10.7° range for the shoulder, the 0.05-0.34 mm and 0.16-0.76° range for the elbow, and the 0.16-1.83 mm and 11-124° range for the TMC joint. Accuracy data from marker- and model-based RSA were not reported in the studies included. Interpretation - RSA is a highly precise method for measurement of early migration of orthopedic implants in the upper limb. However, the precision of rotation measurement is poor in some components. Challenges with RSA in the upper limb include the symmetrical shape of prostheses and the limited size of surrounding bone, leading to over-projection of the markers by the prosthesis. We recommend higher adherence to RSA guidelines and encourage investigators to publish long-term follow-up RSA studies.

Late dislocation of rotating platform in New Jersey Low-Contact Stress knee prosthesis.

PubMed

Huang, Chun-Hsiung; Ma, Hon-Ming; Liau, Jiann-Jong; Ho, Fang-Yuan; Cheng, Cheng-Kung

2002-12-01

Five patients with late rotational dislocation of the rotating platform bearing in the New Jersey Low-Contact Stress total knee arthroplasty are reported. The prostheses had functioned well for 8 to 12 years before failure. Preoperative radiographs showed asymmetric femorotibial joint spaces. Entrapment of the dislocated bearing in three patients and spontaneous reduction of the dislocated bearing in another two patients were seen at revision. Femorotibial ligamentous instability was found after reduction. The retrieved polyethylene bearings showed advanced wear and cold flow deformities and the thickness was reduced. The revision arthroplasty was accomplished by replacement with a thicker bearing element. Progressive femorotibial ligament laxity and reduction of the thickness of polyethylene with wearing break down the originally well-balanced soft tissue tension of the knee. The rotational degree of the rotating platform bearing is unrestricted, which may result in late dislocation. Polyethylene wear is unavoidable in knee prostheses using metal contact with polyethylene even with a mobile-bearing design. Efforts to reduce polyethylene wear are mandatory.

Sensitivity of biomechanical outcomes to independent variations of hindfoot and forefoot stiffness in foot prostheses.

PubMed

Adamczyk, Peter Gabriel; Roland, Michelle; Hahn, Michael E

2017-08-01

Many studies have reported the effects of different foot prostheses on gait, but most results cannot be generalized because the prostheses' properties are seldom reported. We varied hindfoot and forefoot stiffness in an experimental foot prosthesis, in increments of 15N/mm, and tested the parametric effects of these variations on treadmill walking in unilateral transtibial amputees, at speeds from 0.7 to 1.5m/s. We computed outcomes such as prosthesis energy return, center of mass (COM) mechanics, ground reaction forces, and joint mechanics, and computed their sensitivity to component stiffness. A stiffer hindfoot led to reduced prosthesis energy return, increased ground reaction force (GRF) loading rate, and greater stance-phase knee flexion and knee extensor moment. A stiffer forefoot resulted in reduced prosthetic-side ankle push-off and COM push-off work, and increased knee extension and knee flexor moment in late stance. The sensitivity parameters obtained from these tests may be useful in clinical prescription and further research into compensatory mechanisms of joint function. Copyright © 2017 Elsevier B.V. All rights reserved.

A Stereophotogrammetric System For The Detection Of Prosthesis Loosening In Total Hip Arthroplasty

NASA Astrophysics Data System (ADS)

Baumrind, Sheldon; Genant, Harry K.; Hunter, John; Miller, David; Moffitt, Francis; Murray, William R.; Ross, Steven E.

1980-07-01

Loosening of the prosthetic device occurs in about 5% of cases following placement of total hip prostheses (THP). Early detection of loosening is much desired but is difficult to achieve using conventional methods. Due to errors of projection, it is quite possible to fail to detect mobility of even as much as 5 mm on single x-ray films. We are attempting to develop a simplified photogrammetric system suitable for general hospital use which could detect loosening of 0.8 mm at the 95 % level of confidence without use of complex stereoplotting equipment. Metal reference markers are placed in the shaft of the femur and in the acetabular region of the pelvis at the time of surgery. The distances between these reference markers and certain unambiguous points on the prostheses are computed analytically using an X-Y acoustical digitizer (accuracy ± 0.1 mm) and software developed previously for craniofacial measurement. Separate stereopairs of the joint region are taken under weight-bearing and nonweight-bearing conditions. Differences in the measured distances between the bo-ne markers and the prosthetic components on the two stereopairs are taken as indicators of prosthesis loosening. Measurements on a phantom using ten different x-ray stereopairs taken from as many different perspectives have established that true linear distances between reference points and prostheses can be measured at the desired reliability with the present low precision system. Preliminary in vivo measurements indicate that the main unresolved problem is the movement of the subject between the two exposures of each single stereopair. Two possible solutions to this problem are discussed.

[Total Joint Replacement and Return to Sports].

PubMed

Oehler, N; Schmidt, T; Niemeier, A

2016-12-01

Background: An increasing number of physically active patients not only need to know if they will basically be able to engage in sports after undergoing arthroplasty. They also would like to know whether or not they will be able to resume their preoperative activity levels. This article aims to provide an overview of recent data regarding the following questions on hip, knee and shoulder arthroplasty: (1) What is the impact of physical activity on an endoprosthesis? (2) What level of sports can be achieved after an arthroplasty procedure? (3) What types of sport are recommended for patients with an endoprosthesis? Methods: PubMed-based review of the literature. Narrative review focusing on current data from the years 2010 to 2016. Results: The commonly known recommendation to exercise low-impact sports such as hiking, swimming, cycling or golf at a moderate intensity remains valid for all types of prostheses in all joints. There is broad consensus that the benefits of these sports outweigh the negative effects. Having undergone total hip or knee arthroplasty, most patients with a high preoperative activity level return to sports after 3-6 months, albeit with a clear tendency to lower intensity and a shift from high-impact to low-impact sports. Some key questions have to be answered regarding the effects of low-impact sports that are exercised with high intensity, the effects resulting from high-impact sports, effects specific to different types of sport, and possibilities provided by different prosthesis types. In this context, a lot remains to be done to investigate the limits between positive and negative effects resulting from physical activity of varying intensity. New data suggests that generally a higher physical performance level may be achieved than has been traditionally recommended. Early results of unicondylar knee prostheses are far better than those achieved with bicondylar prostheses. In contrast to expert recommendations, shoulder endoprostheses show the highest postoperative activity levels after inverted arthroplasty, followed by anatomic arthroplasty, and the lowest activity level after the implantation of a hemiprosthesis. Conclusion: There is a significant discrepancy between previous expert recommendations and the actual activity levels that may be achieved after the implantation of a joint prosthesis. Future studies have to define the sports level, the type of sports and the type of prosthesis that provide a positive benefit-risk ratio using state-of-the-art low-abrasion bearing surfaces and prosthesis designs. © Georg Thieme Verlag KG Stuttgart · New York.

The role of synovial fluid analysis in the detection of periprosthetic hip and knee infections: a systematic review and meta-analysis.

PubMed

De Fine, Marcello; Giavaresi, Gianluca; Fini, Milena; Illuminati, Andrea; Terrando, Silvio; Pignatti, Giovanni

2018-05-01

This study tried to ascertain (1) the accuracy of synovial fluid white blood cell count and polymorphonucleate percentage in the diagnosis of periprosthetic hip and knee infections, (2) which test yielded superior test performance, and (3) the influence on diagnostic accuracy of study characteristics such as patient number, study design, study level, anatomic site, and threshold value. A systematic search was conducted including papers assessing more effective cutoffs for synovial fluid tests, having comparative design, evaluating an exclusive cohort of hip or knee prostheses, including a clear definition of infected cases, and reporting sufficient data for the calculation of true-positive, false-positive, false-negative, and true-negative. A total of 375 articles were collected and, given the inclusion criteria, ten manuscripts were included. These studies assessed 1155 hip prostheses (276 infected cases) and 1235 knee prostheses (401 infected cases). The specificity of synovial fluid white blood cell count was significantly increased by using the threshold value ≥ 3000 cell/μL (p = 0.006); the sensitivity of polymorphonucleate percentage was significantly higher in detecting knee infections (p = 0.034). Both tests had a high specificity and sensitivity in detecting periprosthetic joint infections, and no clear superiority of one over the other existed. Furthermore, cutoff and anatomic site significantly influenced synovial fluid white blood cell count and polymorphonucleate percentage, respectively. Synovial fluid analysis is adequate in differentiating patients with periprosthetic hip and knee infections. Our data confirms international guidelines suggesting the use of 3000 cell/μL as cutoff threshold for synovial fluid white blood cell count. Since an anatomic site effect has been demonstrated, the goal of future studies will be to identify different cutoffs for hip and knee prostheses.

The Survival of Total Knee Arthroplasty: Current Data from Registries on Tribology: Review Article.

PubMed

Civinini, Roberto; Carulli, Christian; Matassi, Fabrizio; Lepri, Andrea Cozzi; Sirleo, Luigi; Innocenti, Massimo

2017-02-01

Polyethylene (PE) wear is a major contributor to implant loosening following total knee arthroplasty (TKA), and advanced bearings in TKA are being investigated with hopes of reducing or eliminate wear-related loosening. Currently, information on knee tribology is available from national joint registries and may be the best tools to evaluate the efficacy and safety of design innovations in joint arthroplasty. We performed a review of national joint registries trying to answer the following questions: "Which is the main factor directly related to revisions rate in TKA?" and "Are there new bearing options better than conventional ones?" A review was performed of all published annual reports of National Joint Registers, as well as of the literature. The search was carried out using and comparing the National Joint Registers. Current data from registries for total knee arthroplasty indicates that age is the major factor affecting the outcome of primary total knee replacement. The 10-year cumulative revision rate for non-cross-linked PE was 5.8% and for XLPE it was 3.5%. The effect of cross-linked polyethylene was more evident in the younger patients. The survival of the oxidized zirconium (OxZr) femoral component appears better when compared to a similar age group of patients with conventional group of prostheses. Our review suggests that the revision rates are half for the OxZr components compared to conventional CoCr femoral components. Age is the most relevant single factor related to revision rate. Cross-linked PE has a statistical lower revision rate at 10 years compared to conventional PE and, in the OxZr group, the revision rate is 2 times lower than Co-Cr in the same group of age.

MR Imaging with Metal-suppression Sequences for Evaluation of Total Joint Arthroplasty.

PubMed

Talbot, Brett S; Weinberg, Eric P

2016-01-01

Metallic artifact at orthopedic magnetic resonance (MR) imaging continues to be an important problem, particularly in the realm of total joint arthroplasty. Complications often follow total joint arthroplasty and can be expected for a small percentage of all implanted devices. Postoperative complications involve not only osseous structures but also adjacent soft tissues-a highly problematic area at MR imaging because of artifacts from metallic prostheses. Without special considerations, susceptibility artifacts from ferromagnetic implants can unacceptably degrade image quality. Common artifacts include in-plane distortions (signal loss and signal pileup), poor or absent fat suppression, geometric distortion, and through-section distortion. Basic methods to reduce metallic artifacts include use of spin-echo or fast spin-echo sequences with long echo train lengths, short inversion time inversion-recovery (STIR) sequences for fat suppression, a high bandwidth, thin section selection, and an increased matrix. With care and attention to the alloy type (eg, titanium, cobalt-chromium, stainless steel), orientation of the implant, and magnetic field strength, as well as use of proprietary and nonproprietary metal-suppression techniques, previously nondiagnostic studies can yield key diagnostic information. Specifically, sequences such as the metal artifact reduction sequence (MARS), WARP (Siemens Healthcare, Munich, Germany), slice encoding for metal artifact correction (SEMAC), and multiacquisition with variable-resonance image combination (MAVRIC) can be optimized to reveal pathologic conditions previously hidden by periprosthetic artifacts. Complications of total joint arthroplasty that can be evaluated by using MR imaging with metal-suppression sequences include pseudotumoral conditions such as metallosis and particle disease, infection, aseptic prosthesis loosening, tendon injury, and muscle injury. ©RSNA, 2015.

Estimation of appropriate lubricating film thickness in ceramic-on-ceramic hip prostheses

NASA Astrophysics Data System (ADS)

Tauviqirrahman, M.; Muchammad, Bayuseno, A. P.; Ismail, R.; Saputra, E.; Jamari, J.

2016-04-01

Artificial hip prostheses, consisting of femoral head and acetabular cup are widely used and have affected the lives of many people.However, the primary issue associated with the long term performance of hip prostheses is loosening induced by excessive wear during daily activity. Therefore, an effective lubrication is necessary to significantly decrease the wear. To help understand the lubricating performance of such typical hip joint prostheses, in the present paper a hydrodynamic lubrication model based on Reynolds equationwas introduced. The material pairs of ceramic acetabular cup against ceramic femoral head was investegated.The main aim of this study is to investigate of the effect of loading on the formation of lubricating film thickness.The model of a ball-in-socket configuration was considered assuming that the cup was stationary while the ball was to rotate at a steady angular velocityvarying loads.Based on simulation result, it was found that to promote fluid film lubrication and prevent the contacting components leading to wear, the film thickness of lubricant should be determined carefully based on the load applied. This finding may have useful implication in predicting the failure of lubricating synovial fluid film and wear generation in hip prostheses.

Kinematic evaluation of patients with total and reverse shoulder arthroplasty during rehabilitation exercises with different loads.

PubMed

de Toledo, Joelly Mahnic; Loss, Jefferson Fagundes; Janssen, Thomas W; van der Scheer, Jan W; Alta, Tjarco D; Willems, W Jaap; Veeger, DirkJan H E J

2012-10-01

Following shoulder arthroplasty, any well-planned rehabilitation program should include muscle strengthening. However, it is not always clear how different external loads influence shoulder kinematics in patients with shoulder prostheses. The objective of this study was to describe shoulder kinematics and determine the contribution of the scapulothoracic joint to total shoulder motion of patients with total and reverse shoulder arthroplasties and of healthy individuals during rehabilitation exercises (anteflexion and elevation in the scapular plane) using different loading conditions (without external load, 1 kg and elastic resistance). Shoulder motions were measured using an electromagnetic tracking device. A force transducer was used to record force signals during loaded conditions using elastic resistance. Statistical comparisons were made using a three-way repeated-measures analysis of variance with a Bonferroni post hoc testing. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects. The same applies for loaded conditions (1 kg and elastic resistance) relative to unloaded tasks. For scapular internal rotation, upward rotation and posterior tilt no significant differences among groups were found during both exercises. Glenohumeral elevation angles during anteflexion were significantly higher in the total shoulder arthroplasty group compared to the reverse shoulder arthroplasty group. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant. However, compared to healthy subjects, they were. Furthermore, scapular kinematics of patients with shoulder arthroplasty was influenced by implementation of external loads, but not by the type of load. Copyright © 2012 Elsevier Ltd. All rights reserved.

Joint registries as continuous surveillance systems: the experience of the Catalan Arthroplasty Register (RACat).

PubMed

Allepuz, Alejandro; Martínez, Olga; Tebé, Cristian; Nardi, Joan; Portabella, Frederic; Espallargues, Mireia

2014-03-01

The aim was to present results on prosthesis performance in Catalonia for the period 2005-2010. All publicly funded hospitals submit in an electronic format data on hip and knee arthroplasties: patients' insurance identification number, hospital, joint (hip/knee), type of arthroplasty (primary/revision), side (right/left), date of surgery and prosthesis (manufacturer name and catalogue number). A standard survival analysis based on Kaplan-Meier estimation was carried out. Fifty-two hospitals have sent information to the RACat which has data on 36,951 knee and 26,477 hip arthroplasties. Cumulative prostheses revision risks at 3 years were 3.3% (95% CI: 3.1-3.6) for knee, 2.9% (95% CI: 2.5-3.3) for total hip and 2.5% (95% CI: 2.0-3.1) for partial hip. When compared to other registries a higher risk of revision was observed. © 2013.

Three-dimensional human femoral strain analysis using ESPI

NASA Astrophysics Data System (ADS)

Tyrer, J. R.; Heras-Palou, C.; Slater, T.

With age, disease or injury the joints in the human body can wear out or bones may even fail catastrophically. In many cases it is possible to replace joints and bones with artificial components (prostheses). However, prosthetic joints can have a very limited life (often less than 10 years) and require replacement or 'revision'. In order to optimise prosthetic life, it is necessary to improve the design of components and implantation techniques, which is clearly also beneficial to both patients and hospitals.

Silver Nanocoating Technology in the Prevention of Prosthetic Joint Infection

PubMed Central

Gallo, Jiri; Panacek, Ales; Prucek, Robert; Kriegova, Eva; Hradilova, Sarka; Hobza, Martin; Holinka, Martin

2016-01-01

Prosthetic joint infection (PJI) is a feared complication of total joint arthroplasty associated with increased morbidity and mortality. There is a growing body of evidence that bacterial colonization and biofilm formation are critical pathogenic events in PJI. Thus, the choice of biomaterials for implanted prostheses and their surface modifications may significantly influence the development of PJI. Currently, silver nanoparticle (AgNP) technology is receiving much interest in the field of orthopaedics for its antimicrobial properties and a strong anti-biofilm potential. The great advantage of AgNP surface modification is a minimal release of active substances into the surrounding tissue and a long period of effectiveness. As a result, a controlled release of AgNPs could ensure antibacterial protection throughout the life of the implant. Moreover, the antibacterial effect of AgNPs may be strengthened in combination with conventional antibiotics and other antimicrobial agents. Here, our main attention is devoted to general guidelines for the design of antibacterial biomaterials protected by AgNPs, its benefits, side effects and future perspectives in PJI prevention. PMID:28773461

Recent Patents and Designs on Hip Replacement Prostheses

PubMed Central

Derar, H; Shahinpoor, M

2015-01-01

Hip replacement surgery has gone through tremendous evolution since the first procedure in 1840. In the past five decades the advances that have been made in technology, advanced and smart materials innovations, surgical techniques, robotic surgery and methods of fixations and sterilization, facilitated hip implants that undergo multiple design revolutions seeking the least problematic implants and a longer survivorship. Hip surgery has become a solution for many in need of hip joint remedy and replacement across the globe. Nevertheless, there are still long-term problems that are essential to search and resolve to find the optimum implant. This paper reviews several recent patents on hip replacement surgery. The patents present various designs of prostheses, different materials as well as methods of fixation. Each of the patents presents a new design as a solution to different issues ranging from the longevity of the hip prostheses to discomfort and inconvenience experienced by patients in the long-term. PMID:25893020

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

Fatigue limits of titanium-bar joints made with the laser and the electric resistance welding techniques: microstructural characterization and hardness properties.

PubMed

Degidi, Marco; Nardi, Diego; Morri, Alessandro; Sighinolfi, Gianluca; Tebbel, Florian; Marchetti, Claudio

2017-09-01

Fatigue behavior of the titanium bars is of utmost importance for the safe and reliable operation of dental implants and prosthetic constructions based on these implants. To date, however, only few data are available on the fatigue strength of dental prostheses made with electric resistance welding and laser welding techniques. This in-vitro study highlighted that although the joints made with the laser welding approach are credited of a superior tensile strength, joints made with electric resistance welding exhibited double the minimum fatigue strength with respect to the joints made with laser welding (120 vs 60 N).

Temporomandibular Prosthetic Joint Infections Associated With Propionibacterium acnes: A Case Series, and a Review of the Literature.

PubMed

Khader, Ruba; Tingey, Joseph; Sewall, Steven

2017-12-01

The orthopedic literature has shown an increasing incidence of prosthetic joint infections (PJIs) associated with Propionibacterium acnes (P acnes). These infections present serious diagnostic and management challenges to the treating surgeons. In this review, the authors report on cases of P acnes-related temporomandibular joint (TMJ) PJIs that have been diagnosed and treated at their institution. After approval by the institutional review board, information was obtained through a retrospective chart review. Records were retrieved from clinic visits from January 1, 2010 through January 1, 2015 using appropriate International Classification of Diseases, Ninth Revision codes. Data extracted included patient demographics, prostheses details, prosthetic infection history, interventions, diagnostic procedures, and culture processing methods. Of the 7 patients who met the search criteria, 4 (1 with bilateral prostheses) had cultures positive for P acnes. For the 5 TMJ PJIs with cultures positive for P acnes, tissue cultures were obtained in the operating room and processed using mass spectrometry. Symptoms identified in these 4 patients were vague and included pain and intermittent swelling; clinical and radiographic findings were nonspecific. Treatment regimens included oral and parenteral antibiotics and operative interventions. In this case series, the authors report on the management of 4 cases of P acnes-related TMJ PJI. When patients with TMJ prostheses report vague symptoms of swelling and pain that do not fit the typical infection scenario, the surgeon should consider P acnes as a source of infection. Additional case series and retrospective reviews will be necessary before developing prospective trials that could aid in the prevention and management of this infection. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Combined registration of 3D tibia and femur implant models in 3D magnetic resonance images

NASA Astrophysics Data System (ADS)

Englmeier, Karl-Hans; Siebert, Markus; von Eisenhart-Rothe, Ruediger; Graichen, Heiko

2008-03-01

The most frequent reasons for revision of total knee arthroplasty are loosening and abnormal axial alignment leading to an unphysiological kinematic of the knee implant. To get an idea about the postoperative kinematic of the implant, it is essential to determine the position and orientation of the tibial and femoral prosthesis. Therefore we developed a registration method for fitting 3D CAD-models of knee joint prostheses into an 3D MR image. This rigid registration is the basis for a quantitative analysis of the kinematics of knee implants. Firstly the surface data of the prostheses models are converted into a voxel representation; a recursive algorithm determines all boundary voxels of the original triangular surface data. Secondly an initial preconfiguration of the implants by the user is still necessary for the following step: The user has to perform a rough preconfiguration of both remaining prostheses models, so that the fine matching process gets a reasonable starting point. After that an automated gradient-based fine matching process determines the best absolute position and orientation: This iterative process changes all 6 parameters (3 rotational- and 3 translational parameters) of a model by a minimal amount until a maximum value of the matching function is reached. To examine the spread of the final solutions of the registration, the interobserver variability was measured in a group of testers. This variability, calculated by the relative standard deviation, improved from about 50% (pure manual registration) to 0.5% (rough manual preconfiguration and subsequent fine registration with the automatic fine matching process).

A computational method for comparing the behavior and possible failure of prosthetic implants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nielsen, C.; Hollerbach, K.; Perfect, S.

1995-05-01

Prosthetic joint implants currently in use exhibit high Realistic computer modeling of prosthetic implants provides an opportunity for orthopedic biomechanics researchers and physicians to understand possible in vivo failure modes, without having to resort to lengthy and costly clinical trials. The research presented here is part of a larger effort to develop realistic models of implanted joint prostheses. The example used here is the thumb carpo-metacarpal (cmc) joint. The work, however, can be applied to any other human joints for which prosthetic implants have been designed. Preliminary results of prosthetic joint loading, without surrounding human tissue (i.e., simulating conditions undermore » which the prosthetic joint has not yet been implanted into the human joint), are presented, based on a three-dimensional, nonlinear finite element analysis of three different joint implant designs.« less

Detection of total hip prostheses at airport security checkpoints: how has heightened security affected patients?

PubMed

Johnson, Aaron J; Naziri, Qais; Hooper, Hasan A; Mont, Michael A

2012-04-04

The sensitivity of airport security screening measures has increased substantially during the past decade, but few reports have examined how this affects patients who have undergone hip arthroplasty. The purpose of this study was to determine the experiences of patients who had hip prostheses and who passed through airport security screenings. A consecutive series of 250 patients who presented to the office of a high-volume surgeon were asked whether they had had a hip prosthesis for at least one year and, if so, whether they had flown on a commercial airline within the past year. Patients who responded affirmatively to both questions were asked to complete a written survey that included questions about which joint(s) had been replaced, the number of encounters with airport security, the frequency and location of metal detector activation, any additional screening procedures that were utilized, whether security officials requested documentation regarding the prosthesis, the degree of inconvenience, and other relevant information. Of the 143 patients with hip replacements who traveled by air, 120 (84%) reported triggering the alarm and required wanding with a handheld detector. Twenty-five of these patients reported subsequently having to undergo further inspection, including additional wanding, being patted down, and in two cases having to undress in a private room to show the incision. Ninety-nine (69%) of the 143 patients reported that the prosthetic joint caused an inconvenience while traveling. This study provides interesting and critical information that allows physicians to understand the real-world implications of implanted orthopaedic devices for patients who are traveling where there has been heightened security since September 11, 2001. Patients should be counseled that they should expect delays and be prepared for such inconveniences, but that these are often only momentary. This information could relieve some anxiety and concerns that patients may have prior to traveling.

Thermoelastic stress analysis to validate tibial fixation technique in total ankle prostheses - a pilot study.

PubMed

Ficklscherer, Andreas; Wegener, Bernd; Niethammer, Thomas; Pietschmann, Matthias F; Müller, Peter E; Jansson, Volkmar; Trouillier, Hans-Heinrich

2013-03-01

Recent literature has shown a persistently high rate of aseptic loosening of the tibial component in total ankle prostheses. We analyzed the interface between the tibial bone and tibial component with a thermoelastic stress analysis to demonstrate load transmission onto the distal tibia. In this regard, we used two established ankle prostheses, which were implanted in two human cadaveric and in two third-generation composite tibia bones (Sawbones®, Sweden). Subsequently, the bones were attached to a hydropulser and a sinusoidal load of 700 N was applied. Both prostheses had an inhomogeneous load transmission onto the distal tibia. Instead of distributing load equally to the subarticular bone, forces were focused around the bolting stem, accumulating as stress maxima with forces up to 90 MPa. Furthermore, we were able to demonstrate load transmission into the metaphysis of the bone. As demonstrated in this study, anchoring systems with stems used in all established total ankle prostheses lead to an inhomogeneous load transmission onto the distal tibia, and furthermore, to a distribution of load into the weaker metaphyseal bone. For these reasons, we favor a prosthetic design with minimal bone resection and without any stem or stem-like anchoring system, which facilitates a homogeneous load transmission onto the distal tibia. Thermoelastic stress analysis proved to be a fast and easy-to-perform method to visualize load transmission.

Robotic cadaver testing of a new total ankle prosthesis model (German Ankle System).

PubMed

Richter, Martinus; Zech, Stefan; Westphal, Ralf; Klimesch, Yvone; Gosling, Thomas

2007-12-01

An investigation was carried out into possible increased forces, torques, and altered motions during load-bearing ankle motion after implantation of two different total ankle prostheses. We hypothesized that the parameters investigated would not differ in relation to the two implants compared. We included two different ankle prostheses (Hintegra, Newdeal, Vienne, France; German Ankle System, R-Innovation, Coburg, Germany). The prostheses were implanted in seven paired cadaver specimens. The specimens were mounted on an industrial robot that enables complex motion under predefined conditions (RX 90, Stäubli, Bayreuth, Germany). The robot detected the load-bearing (30 kg) motion of the 100(th) cycle of the specimens without prostheses as the baseline for the later testing, and mimicked that exact motion during 100 cycles after the prostheses were implanted. The resulting forces, torques, and bone motions were recorded and the differences between the prostheses compared. The Hintegra and German Ankle System, significantly increased the forces and torques in relation to the specimen without a prosthesis with one exception (one-sample-t-test, each p < or = 0.01; exception, parameter lateral force measured with the German Ankle System, p = 0.34). The force, torque, and motion differences between the specimens before and after implantation of the prostheses were lower with the German Ankle System than with the Hintegra (unpaired t-test, each p < or = 0.05). The German Ankle System prosthesis had less of an effect on resulting forces and torques during partial weightbearing passive ankle motion than the Hintegra prosthesis. This might improve function and minimize loosening during the clinical use.

Evaluation of the Alteration of Occlusal Distribution in Unilateral Free-End and Intermediate Missing Cases.

PubMed

Kon, Kazuhiro; Shiota, Makoto; Sakuyama, Aoi; Ozeki, Maho; Kozuma, Wataru; Kawakami, Sawako; Kasugai, Shohei

2017-02-01

The present study aimed to evaluate the effect of implant prostheses on the occlusal force and area as well as the distribution of occlusal loading in unilateral free-end and intermediate missing cases. Fourteen healthy subjects (7 free-end missing cases in the first and second molars and 7 intermediate missing cases in the first molar region) were included. Six months after the implant prosthesis was placed, an occlusal evaluation was performed with or without the implant superstructure by using Dental Prescale film and an occluder device. In free-end missing cases, the total occlusal force and area, implant-side occlusal force and area, and implant-side occlusal force and area of the residual natural teeth were significantly affected by the implant prostheses. In intermediate missing cases, the implant-side occlusal force of the residual natural teeth was significantly affected by the implant prostheses. In free-end missing cases, the proportions of implant-side occlusal force, non-implant-side occlusal force, and implant-side occlusal force of the residual natural teeth relative to the total occlusal force were significantly affected by the implant prostheses. In the intermediate missing cases, the proportion of the implant-side occlusal force of the residual natural teeth relative to the total occlusal force was significantly affected by the implant prostheses. The proportion of the occlusal area was also significantly affected. In free-end missing cases, implant prostheses significantly increased the occlusal force and area, which resulted in the proper occlusal distribution. In intermediate missing cases, an implant prosthesis may only improve the same-side occlusal loading of the natural teeth.

[Clinical evaluation of "All-on-Four" provisional prostheses reinforced with carbon fibers].

PubMed

Li, Bei-bei; Lin, Ye; Cui, Hong-yan; Hao, Qiang; Xu, Jia-bin; Di, Ping

2016-02-18

To assess the clinical effects of carbon fiber reinforcement on the "All-on-Four" provisional prostheses. Provisional prostheses were divided into control group and carbon fiber reinforcing group according to whether carbon fiber reinforcement was used in the provisional prostheses base resin. In our study, a total of 60 patients (32 males and 28 females) with 71 provisional prostheses(28 maxilla and 43 mandible)were enrolled between April 2008 and December 2012 for control group; a total of 23 patients (13 males and 10 females) with 28 provisional prostheses (9 maxillas and 19 mandibles) were enrolled between January 2013 and March 2014 for carbon fiber reinforcing group. The information of provisional prostheses in the patients was recorded according to preoperative examination. We used the date of definitive prosthesis restoration as the cut-off point, observing whether fracture occurred on the provisional prostheses in the two groups. Additionally we observed whether fiber exposure occurred on the tissue surface of the provisional prostheses and caused mucosal irritation. The interface between the denture base resin and the fibers was examined using scanning electron microscopy (SEM). The age [(57.3 ± 10.1) years vs.(55.1 ± 11.4) years], gender (32 males and 28 females vs. 13 males and 10 females), maxilla and mandible distributions (28 maxillas and 43 mandibles vs. 9 maxillas and 19 mandibles), the number of extraction jaws (46 vs. 23), the average using time [(7.8 ± 1.3) months vs. (7.5 ± 1.1) months], and the opposing dentition distributions of provisional prostheses of the patients showed no significant differences between the control and reinforcing groups. There were 21(29.6%) fractures that occurred on the 71 provisional prostheses in the control group; there was no fracture that occurred on the 28 provisional prosthesesin the carbon fiber reinforcing group. The fracture rate of the carbon fiber reinforcing group was significantly lower than that of the control group (P=0.001). No carbon fiber exposure and mucosal irritation were observed from clinical examination.SEM revealed relatively continuous contact between the fiber and acrylic resin, and the resin particles adhered on the surface of the carbon fibers. The addition of carbon fibers between abutments placed on "All-on-Four" provisional fixed denture base resin may be clinically effective in preventing "All-on-Four" denture fracture and can provide several advantages for clinical use.

Fabrication of low cost soft tissue prostheses with the desktop 3D printer

NASA Astrophysics Data System (ADS)

He, Yong; Xue, Guang-Huai; Fu, Jian-Zhong

2014-11-01

Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

Fabrication of low cost soft tissue prostheses with the desktop 3D printer

PubMed Central

He, Yong; Xue, Guang-huai; Fu, Jian-zhong

2014-01-01

Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods. PMID:25427880

Fabrication of low cost soft tissue prostheses with the desktop 3D printer.

PubMed

He, Yong; Xue, Guang-huai; Fu, Jian-zhong

2014-11-27

Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

Computer Assisted Surgery and Current Trends in Orthopaedics Research and Total Joint Replacements

NASA Astrophysics Data System (ADS)

Amirouche, Farid

2008-06-01

Musculoskeletal research has brought about revolutionary changes in our ability to perform high precision surgery in joint replacement procedures. Recent advances in computer assisted surgery as well better materials have lead to reduced wear and greatly enhanced the quality of life of patients. The new surgical techniques to reduce the size of the incision and damage to underlying structures have been the primary advance toward this goal. These new techniques are known as MIS or Minimally Invasive Surgery. Total hip and knee Arthoplasties are at all time high reaching 1.2 million surgeries per year in the USA. Primary joint failures are usually due to osteoarthristis, rheumatoid arthritis, osteocronis and other inflammatory arthritis conditions. The methods for THR and TKA are critical to initial stability and longevity of the prostheses. This research aims at understanding the fundamental mechanics of the joint Arthoplasty and providing an insight into current challenges in patient specific fitting, fixing, and stability. Both experimental and analytical work will be presented. We will examine Cementless total hip arthroplasty success in the last 10 years and how computer assisted navigation is playing in the follow up studies. Cementless total hip arthroplasty attains permanent fixation by the ingrowth of bone into a porous coated surface. Loosening of an ingrown total hip arthroplasty occurs as a result of osteolysis of the periprosthetic bone and degradation of the bone prosthetic interface. The osteolytic process occurs as a result of polyethylene wear particles produced by the metal polyethylene articulation of the prosthesis. The total hip arthroplasty is a congruent joint and the submicron wear particles produced are phagocytized by macrophages initiating an inflammatory cascade. This cascade produces cytokines ultimately implicated in osteolysis. Resulting bone loss both on the acetabular and femoral sides eventually leads to component instability. As patients are living longer and total hip arthroplasty is performed in younger patients the risks of osteolysis associated with cumulative wear is increased. Computer-assisted surgery is based on sensing feedback; vision and imaging that help surgeons align the patient's joints during total knee or hip replacement with a degree of accuracy not possible with the naked eye. For the first time, the computer feedback is essential for ligament balancing and longevity of the implants. The computers navigation systems also help surgeons to use smaller incisions instead of the traditional larger openings. Small-incision surgery offers the potential for faster recovery, less bleeding and less pain for patients. The development of SESCAN imaging technique to create a patient based model of a 3D joint will be presented to show the effective solution of complex geometry of joints.

Frequency of technical complications in fixed implant prosthesis: the effect of prosthesis screw emergence correction by CAD-CAM.

PubMed

Anitua, Eduardo; Flores, Carlos; Piñas, Laura; Alkhraisat, Mohammad

2018-06-05

CAD-CAM technology permits the angular correction of screw emergence into the prosthesis, however there is lack of controlled clinical studies that assess the frequency of technical complications in angled screw channel restorations. This controlled clinical study was designed to assess technical incidences in angled screw channel restorations. Patients having implant prosthesis placed between November, 2014 and December, 2015 were screened. The patients were selected if they received prosthesis with up to 30º correction of the prosthesis screw emergence and had at least one non-angulated prosthesis (screw-retained). All the prostheses were located completely/partially in the posterior region. The frequency of technical complications was the principal variable. A total of 52 patients with a mean age of 62 ± 10 years participated with a total 110 prostheses (55 in the test group and 55 in the control group). A total of 11 technical complications occurred (7 in the test group and 4 in the control group). These differences were not statistically significant. All the prostheses in both groups survived the follow-up. The correction of the screw emergence into the prosthesis has not increased the risk of technical complications in CAD-CAM implant prostheses.

Long-term clinical outcomes and survivorship of press-fit condylar sigma fixed-bearing and mobile-bearing total knee prostheses in the same patients.

PubMed

Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik; Kulkarni, Sourabh S; Kim, Yoon-Hong

2014-10-01

We are aware of no study that has compared press-fit condylar Sigma fixed-bearing and mobile-bearing total knee prostheses in the same patients after more than ten years of follow-up. The purpose of the current study was to compare these two implants with respect to the functional and radiographic results, prevalence of osteolysis, and overall revision rates at a mean of 12.1 years of follow-up. The study consisted of a consecutive series of 444 patients (mean age [and standard deviation], 66.5 ± 7.4 years) who underwent simultaneous bilateral total knee arthroplasty, with one side treated immediately after the other. All of the patients received a press-fit condylar Sigma mobile-bearing prosthesis on one side and a press-fit condylar Sigma fixed-bearing prosthesis on the contralateral side. The minimum duration of follow-up was ten years (mean, 12.1 years; range, ten to thirteen years). At the time of each follow-up visit, the patients were assessed clinically and radiographically. Postoperative total knee scores (95 and 94 points), Western Ontario and McMaster Universities Osteoarthritis Index (19 and 18 points), University of California, Los Angeles activity score (both prostheses, 5 points), range of motion (129° ± 6.3° and 127° ± 6.8°), and radiographic findings did not differ significantly between the press-fit condylar Sigma mobile and fixed-bearing designs at the final follow-up. The prevalence of aseptic loosening (1.4% and 1.8%) did not differ significantly between the mobile and fixed-bearing implant designs. No knee in either group had osteolysis. The estimated survival rate with revision as the end point was 98.2% (95% confidence interval, 91% to 99%) and 97.5% (95% confidence interval, 91% to 99%) at 12.1 years for the mobile and fixed-bearing implant groups, respectively. The results of the present long-term clinical study suggest that excellent clinical and radiographic results were achieved with both the press-fit condylar Sigma mobile and fixed-bearing cruciate-retaining total knee designs. We found no significant clinical advantage for a mobile-bearing over a fixed-bearing total knee prosthesis. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects.

PubMed

Choudhury, Dipankar; Rebenda, David; Sasaki, Shinya; Hekrle, Pavel; Vrbka, Martin; Zou, Min

2018-05-01

This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20-50 µm lateral size and 1 ± 0.2 µm depths were fabricated on CrCoMo hip joint femoral heads using a picosecond laser. Tribological studies were performed using a pendulum hip joint simulator to apply continuous swing flexion-extension motions. The results revealed a significantly enhanced lubricant film thickness (≥ 500 nm) with micro-dimpled prosthesis heads at equilibrium position after the lubricant film has fully developed. The average lubricant film thickness of dimpled prostheses with square- and triangular-shaped dimple arrays over time is about 3.5 that of the non-dimpled prosthesis (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 nm) demonstrating a hydrodynamic lubrication. Hardly any scratches appeared on the post-experimental prosthesis with square-shaped dimple array and only a few scratches were found on the post-experimental prosthesis with triangular-shaped dimple arrays. Thus, prostheses with square-shaped dimple arrays could be a potential solution for durable artificial hip joints. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluation of a noninvasive command scheme for upper-limb prostheses in a virtual reality reach and grasp task.

PubMed

Kaliki, Rahul R; Davoodi, Rahman; Loeb, Gerald E

2013-03-01

C5/C6 tetraplegic patients and transhumeral amputees may be able to use voluntary shoulder motion as command signals for a functional electrical stimulation system or transhumeral prosthesis. Stereotyped relationships, termed "postural synergies," among the shoulder, forearm, and wrist joints emerge during goal-oriented reaching and transport movements as performed by able-bodied subjects. Thus, the posture of the shoulder can potentially be used to infer the desired posture of the elbow and forearm joints during reaching and transporting movements. We investigated how well able-bodied subjects could learn to use a noninvasive command scheme based on inferences from these postural synergies to control a simulated transhumeral prosthesis in a virtual reality task. We compared the performance of subjects using the inferential command scheme (ICS) with subjects operating the simulated prosthesis in virtual reality according to complete motion tracking of their actual arm and hand movements. Initially, subjects performed poorly with the ICS but improved rapidly with modest amounts of practice, eventually achieving performance only slightly less than subjects using complete motion tracking. Thus, inferring the desired movement of distal joints from voluntary shoulder movements appears to be an intuitive and noninvasive approach for obtaining command signals for prostheses to restore reaching and grasping functions.

Effect of gap distance on tensile strength of preceramic base metal solder joints.

PubMed

Fattahi, Farnaz; Motamedi, Milad

2011-01-01

In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

Microscopical analysis of synovial fluid wear debris from failing CoCr hip prostheses

NASA Astrophysics Data System (ADS)

Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.

2010-07-01

Metal on metal hip joint prostheses are now commonly implanted in patients with hip problems. Although hip replacements largely go ahead problem free, some complications can arise such as infection immediately after surgery and aseptic necrosis caused by vascular complications due to surgery. A recent observation that has been made at Manchester is that some Cobalt Chromium (CoCr) implants are causing chronic pain, with the source being as yet unidentified. This form of replacement failure is independent of surgeon or hospital and so some underlying body/implant interface process is thought to be the problem. When the synovial fluid from a failed joint is examined particles of metal (wear debris) can be found. Transmission Electron Microscopy (TEM) has been used to look at fixed and sectioned samples of the synovial fluid and this has identified fine (< 100 nm) metal and metal oxide particles within the fluid. TEM EDX and Electron Energy Loss Spectroscopy (EELS) have been employed to examine the composition of the particles, showing them to be chromium rich. This gives rise to concern that the failure mechanism may be associated with the debris.

Development of a Mandibular Motion Simulator for Total Joint Replacement

PubMed Central

Celebi, Nukhet; Rohner, E. Carlos; Gateno, Jaime; Noble, Philip C.; Ismaily, Sabir K.; Teichgraeber, John F.; Xia, James J.

2015-01-01

Purpose The purpose of this study was to develop a motion simulator capable of recreating and recording the full range of mandibular motions in a cadaveric preparation for an intact temporomandibular joint (TMJ) and after total joint replacement. Material and Methods A human cadaver head was used. Two sets of tracking balls were attached to the forehead and mandible, respectively. Computed tomographic (CT) scan was performed and 3-dimensional CT models of the skull were generated. The cadaver head was then dissected to attach the muscle activation cables and mounted onto the TMJ simulator. Realistic jaw motions were generated through the application of the following muscle forces: lateral pterygoid muscle, suprahyoid depressors (geniohyoid, mylohyoid, and digastric muscles), and elevator muscles. To simulate muscle contraction, cables were inserted into the mandible at the center area of each muscle's attachment. To provide a minimum mouth closing force at the initial position, the elevator muscles were combined at the anterior mandible. During mandibular movement, each motion was recorded using a high-resolution laser scanner. The right TMJ of the same head was reconstructed with a total TMJ prosthesis. The same forces were applied and the jaw motions were recorded again. CT scan was performed and 3-dimensional CT models of the skull with TMJ prosthesis were generated. Results Mandibular motions, before and after TMJ replacement, with and without lateral pterygoid muscle reattachment, were re-created in a cadaveric preparation. The laser-scanned data during the mandibular motion were used to drive 3-dimensional CT models. A movie for each mandibular motion was subsequently created for motion path analysis. Compared with mandibular motion before TMJ replacement, mandibular lateral and protrusive motions after TMJ replacement, with and without lateral pterygoid muscle reattachment, were greatly limited. The jaw motion recorded before total joint replacement was applied to the mandibular and prostheses models after total TMJ replacement. The condylar component was observed sinking into the fossa during jaw motion. Conclusion A motion simulator capable of re-creating and recording full range of mandibular motions in a cadaveric preparation has been developed. It can be used to simulate mandibular motions for the intact TMJ and total joint prosthesis, and to re-create and record their full range of mandibular motions. In addition, the full range of the recorded motion can be re-created as motion images in a computer. These images can be used for motion path analysis and to study the causation of limited range of motion after total joint replacement and strategies for improvement. PMID:21050636

Effect of prosthesis endplate lordosis angles on L5-S1 kinematics after disc arthroplasty.

PubMed

Tsitsopoulos, Parmenion P; Wojewnik, Bartosz; Voronov, Leonard I; Havey, Robert M; Renner, Susan M; Zelenakova, Julia; McIntosh, Braden; Carandang, Gerard; Abjornson, Celeste; Patwardhan, Avinash G

2012-06-01

We hypothesized that L5-S1 kinematics will not be affected by the lordosis distribution between the prosthesis endplates. Twelve cadaveric lumbosacral spines (51.3 ± 9.8 years) were implanted with 6° or 11° prostheses (ProDisc-L) with four combinations of superior/inferior lordosis (6°/0°, 3°/3°, 11°/0°, 3°/8°). Specimens were tested intact and after prostheses implantation with different lordosis distributions. Center of rotation (COR) and range of motion (ROM) were quantified. Six-degree lordosis prostheses (n = 7) showed no difference in flexion-extension ROM, regardless of design (6°/0° or 3°/3°) (p > 0.05). In lateral bending (LB), both designs reduced ROM (p < 0.05). In axial rotation, only the 3°/3° design reduced ROM (p < 0.05). Eleven-degree lordosis prostheses (n = 5) showed no difference in flexion-extension ROM for either design (p > 0.05). LB ROM decreased with distributed lordosis prostheses (3°/8°) (p < 0.05). Overall, L5-S1 range of motion was not markedly influenced by lordosis distribution among the two prosthesis endplates. The ProDisc-L prosthesis design where all lordosis is concentrated in the superior endplate yielded COR locations that were anterior and caudal to intact controls. The prosthesis with lordosis distributed between the two endplates yielded a COR that tended to be closer to intact. Further clinical and biomechanical studies are needed to assess the long-term impact of lordosis angle distribution on the fate of the facet joints.

The effects of progressive lateralization of the joint center of rotation of reverse total shoulder implants.

PubMed

Costantini, Oren; Choi, Daniel S; Kontaxis, Andreas; Gulotta, Lawrence V

2015-07-01

There has been a renewed interest in lateralizing the center of rotation (CoR) in implants used in reverse shoulder arthroplasty. The aim of this study was to determine the sensitivity of lateralization of the CoR on the glenohumeral joint contact forces, muscle moment arms, torque across the bone-implant interface, and the stability of the implant. A 3-dimensional virtual model was used to investigate how lateralization affects deltoid muscle moment arm and glenohumeral joint contact forces. This model was virtually implanted with 5 progressively lateralized reverse shoulder prostheses. The joint contact loads and deltoid moment arms were calculated for each lateralization over the course of 3 simulated standard humerothoracic motions. Lateralization of the CoR leads to an increase in the overall joint contact forces across the glenosphere. Most of this increased loading occurred through compression, although increases in anterior/posterior and superior/inferior shear were also observed. Moment arms of the deltoid consistently decreased with lateralization. Bending moments at the implant interface increased with lateralization. Progressive lateralization resulted in improved stability ratios. Lateralization results in increased joint loading. Most of that loading occurs through compression, although there were also increases in shear forces. Anterior/posterior shear is currently not accounted for in implant fixation studies, leaving its effect on implant fixation unknown. Future studies should incorporate shear forces into their models to more accurately assess fixation methods. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

[Total hip endoprosthesis following resection arthroplasty].

PubMed

Engelbrecht, E; Siegel, A; Kappus, M

1995-08-01

From 1976 to December 1994, a total of 347 patients underwent implantation of a hip prosthesis at the ENDO-Klinik for treatment of an unsatisfactory condition following resection arthroplasty. From 1976 to 1987, 143 patients were treated and in 1989 the results obtained in these patients were analysed: 99 of them were available for a follow-up examination in 1989, and 64 for a further examination in 1995. In 130 cases infection had been the reason for joint resection. At the time of the prosthesis operation (1-20 years later) intraoperative biopsy revealed that infection was still present in 41 cases (31.5%). Only 15 of these infections had been detected preoperatively by joint aspiration. This shows that the value of resection arthroplasty as a method of treating periprosthetic infection is limited and lends support to the one-stage exchange operation, which is the method we prefer in cases of infected hip prostheses. The operative technique and preparation for implantation of the prosthesis are described, as are septic and aseptic complications and the measures that can be taken to treat them. In spite of the patients' generally poor initial condition and with due consideration for the further revision operations, the medium-term results finally obtained are poor in only 9%.

Comparison of patellofemoral outcomes after TKA using two prostheses with different patellofemoral design features.

PubMed

Bae, Dae Kyung; Baek, Jong Hun; Yoon, Kyung Tack; Son, Hyuck Sung; Song, Sang Jun

2017-12-01

The purpose of the present study was to compare the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, including outcomes related to compatibility of the patellofemoral joint. The clinical and radiographic results of 81 patients (100 knees) who underwent TKA using the specific prosthesis (group A) were compared with those in a control group who underwent TKA using the other prosthesis (group B). The presence of anterior knee joint pain, patellar crepitation, and patellar clunk syndrome was also checked. The function score and maximum flexion angle at the last follow-up were slightly better in group A than those in group B (92.0 ± 2.3 vs. 90.6 ± 4.2) (133.6° ± 8.4° vs. 129.6° ± 11.4°). Anterior knee pain was observed in 6 knees and patellar crepitation in four knees in group A. In group B, these symptoms were observed in 22 knees and 18 knees, respectively. There was no patellar clunk syndrome in either group. The alignment was corrected with satisfactory positioning of components. The patellar height remained unchanged after TKA in the two groups. The differences between preoperative and postoperative patellar tilt angle and patellar translation were small. When comparing the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, TKA using the specific prosthesis provided satisfactory results with less clinical symptoms related to the patellofemoral kinematics with TKA using the other prosthesis. III.

Effect of Gap Distance on Tensile Strength of Preceramic Base Metal Solder Joints

PubMed Central

Fattahi, Farnaz; Motamedi, Milad

2011-01-01

Background and aims In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Materials and methods Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. Results The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. Conclusion There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints. PMID:22991610

Experience with the use of a partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft.

PubMed

Birk, Stephanie; Brase, Christoph; Hornung, Joachim

2014-08-01

In the further development of alloplastic prostheses for use in middle ear surgery, the Dresden and Cologne University Hospitals, working together with a company, introduced a new partial ossicular replacement prosthesis in 2011. The ball-and-socket joint between the prosthesis and the shaft mimics the natural articulations between the malleus and incus and between the incus and stapes, allowing reaction to movements of the tympanic membrane graft, particularly during the healing process. Retrospective evaluation To reconstruct sound conduction as part of a type III tympanoplasty, partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft was implanted in 60 patients, with other standard partial ossicular replacement prosthesis implanted in 40 patients and 64 patients. Pure-tone audiometry was carried out, on average, 19 and 213 days after surgery. Results of the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft were compared with those of the standard prostheses. Early measurements showed a mean improvement of 3.3 dB in the air-bone gap (ABG) with the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft, giving similar results than the standard implants (6.6 and 6.0 dB, respectively), but the differences were not statistically significant. Later measurements showed a statistically significant improvement in the mean ABG, 11.5 dB, compared with 4.4 dB for one of the standard partial ossicular replacement prosthesis and a tendency of better results to 6.9 dB of the other standard prosthesis. In our patients, we achieved similarly good audiometric results to those already published for the partial ossicular replacement prosthesis with a ball-and-socket joint between the plate and the shaft. Intraoperative fixation posed no problems, and the postoperative complication rate was low.

21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

Development of a prosthesis shoulder mechanism for upper limb amputees: application of an original design methodology to optimize functionality and wearability.

PubMed

Troncossi, Marco; Borghi, Corrado; Chiossi, Marco; Davalli, Angelo; Parenti-Castelli, Vincenzo

2009-05-01

The application of a design methodology for the determination of the optimal prosthesis architecture for a given upper limb amputee is presented in this paper along with the discussion of its results. In particular, a novel procedure was used to provide the main guidelines for the design of an actuated shoulder articulation for externally powered prostheses. The topology and the geometry of the new articulation were determined as the optimal compromise between wearability (for the ease of use and the patient's comfort) and functionality of the device (in terms of mobility, velocity, payload, etc.). This choice was based on kinematic and kinetostatic analyses of different upper limb prosthesis models and on purpose-built indices that were set up to evaluate the models from different viewpoints. Only 12 of the 31 simulated prostheses proved a sufficient level of functionality: among these, the optimal solution was an articulation having two actuated revolute joints with orthogonal axes for the elevation of the upper arm in any vertical plane and a frictional joint for the passive adjustment of the humeral intra-extra rotation. A prototype of the mechanism is at the clinical test stage.

Rapid Molecular Microbiologic Diagnosis of Prosthetic Joint Infection

PubMed Central

Cazanave, Charles; Greenwood-Quaintance, Kerryl E.; Hanssen, Arlen D.; Karau, Melissa J.; Schmidt, Suzannah M.; Gomez Urena, Eric O.; Mandrekar, Jayawant N.; Osmon, Douglas R.; Lough, Lindsay E.; Pritt, Bobbi S.; Steckelberg, James M.

2013-01-01

We previously showed that culture of samples obtained by prosthesis vortexing and sonication was more sensitive than tissue culture for prosthetic joint infection (PJI) diagnosis. Despite improved sensitivity, culture-negative cases remained; furthermore, culture has a long turnaround time. We designed a genus-/group-specific rapid PCR assay panel targeting PJI bacteria and applied it to samples obtained by vortexing and sonicating explanted hip and knee prostheses, and we compared the results to those with sonicate fluid and periprosthetic tissue culture obtained at revision or resection arthroplasty. We studied 434 subjects with knee (n = 272) or hip (n = 162) prostheses; using a standardized definition, 144 had PJI. Sensitivities of tissue culture, of sonicate fluid culture, and of PCR were 70.1, 72.9, and 77.1%, respectively. Specificities were 97.9, 98.3, and 97.9%, respectively. Sonicate fluid PCR was more sensitive than tissue culture (P = 0.04). PCR of prosthesis sonication samples is more sensitive than tissue culture for the microbiologic diagnosis of prosthetic hip and knee infection and provides same-day PJI diagnosis with definition of microbiology. The high assay specificity suggests that typical PJI bacteria may not cause aseptic implant failure. PMID:23658273

Dorsal surgical stabilisation using tension bands for treatment of traumatic atlanto-occipital instability in a cat.

PubMed

Vedrine, B; Maurin, M P

2017-12-01

An atlanto-occipital instability secondary to a dog bite was diagnosed in a 4-year-old Persian cat. Dorsal stabilisation of the instability was made with two OrthoFiber prostheses (Securos), which were used as tension bands between the nuchal crests of the occipital bone and the spinous process of the axis. Total recovery was achieved 4 days after surgery. Normal alignment of the atlanto-occipital joint was observed on survey radiographs taken 6 weeks post-surgery. Although the right loop had failed, the alignment was still normal and no neurological after-effects could be identified. Dorsal divergent tension bands between the nuchal crests of the occipital bone and the spinous process of the axis can be used to stabilise traumatic atlanto-occipital instability. © 2017 Australian Veterinary Association.

Plausibility and parameter sensitivity of micro-finite element-based joint load prediction at the proximal femur.

PubMed

Synek, Alexander; Pahr, Dieter H

2018-06-01

A micro-finite element-based method to estimate the bone loading history based on bone architecture was recently presented in the literature. However, a thorough investigation of the parameter sensitivity and plausibility of this method to predict joint loads is still missing. The goals of this study were (1) to analyse the parameter sensitivity of the joint load predictions at one proximal femur and (2) to assess the plausibility of the results by comparing load predictions of ten proximal femora to in vivo hip joint forces measured with instrumented prostheses (available from www.orthoload.com ). Joint loads were predicted by optimally scaling the magnitude of four unit loads (inclined [Formula: see text] to [Formula: see text] with respect to the vertical axis) applied to micro-finite element models created from high-resolution computed tomography scans ([Formula: see text]m voxel size). Parameter sensitivity analysis was performed by varying a total of nine parameters and showed that predictions of the peak load directions (range 10[Formula: see text]-[Formula: see text]) are more robust than the predicted peak load magnitudes (range 2344.8-4689.5 N). Comparing the results of all ten femora with the in vivo loading data of ten subjects showed that peak loads are plausible both in terms of the load direction (in vivo: [Formula: see text], predicted: [Formula: see text]) and magnitude (in vivo: [Formula: see text], predicted: [Formula: see text]). Overall, this study suggests that micro-finite element-based joint load predictions are both plausible and robust in terms of the predicted peak load direction, but predicted load magnitudes should be interpreted with caution.

Biodeterioration of medical-grade silicone rubber used for voice prostheses: a SEM study.

PubMed

Neu, T R; Van der Mei, H C; Busscher, H J; Dijk, F; Verkerke, G J

1993-05-01

Silicone voice prostheses used for rehabilitation of speech after total laryngectomy are inserted in an non-sterile habitat. Deposits on explanted Groningen Button voice prostheses revealed a biofilm, due to heavy colonization of the silicone surface by bacteria and yeasts. Furthermore, it was demonstrated by scanning electron microscopy on sectioned explants that the silicone material was deteriorated by filamentous and vegetative yeast cells. The different explants showed a variety of sharp-edged, discrete yeast colonies. The yeasts grew just under the silicone surface and up to 700 microns into the silicone material. Finally, nine different types of defects in the silicone material created by the yeasts are described. This deterioration of the silicone by yeasts seems to be the main reason for the failure and the frequent replacement of the prostheses. The mechanisms of silicone deterioration are still hypothetical.

Clinical Results of 40 Consecutive Basal Thumb Prostheses and No CRPS Type I After Vitamin C Prophylaxis.

PubMed

Zollinger, Paul E; Unal, Halil; Ellis, Maarten L; Tuinebreijer, Wim E

2010-02-17

Complex regional pain syndrome (CRPS) type I may occur as complication after any type of surgery for basal joint arthritis of the thumb. We investigated prospectively in an ongoing study our results after a fully standardized treatment with a total joint prosthesis under vitamin C prophylaxis.Patients with trapeziometacarpal arthritis stage II or III according to Dell, and no benefit from conservative treatment, were selected to undergo joint replacement with a semi-constrained hydroxyapatite coated prosthesis.First web opening and visual analogue scale (VAS) scores for pain, activities of daily living (ADL) and satisfaction were taken pre and postoperatively. Vitamin C 500 mg daily was started two days prior to surgery during 50 days as prevention for CRPS. Post-operative treatment was functional.We performed 40 implantations for trapeziometacarpal arthritis in 34 patients (mean age 60.8 years; 27 females, 7 males) with a mean follow-up of 44 months. Operations were performed in day care under regional (or general) anesthesia.First web opening increased with 15.4 degrees and there was a significant improvement for pain, ADL and satisfaction as well (p = 0.000). Patient satisfaction was strongly associated with the amount of pain reduction. According to the Veldman and IASP criteria, there were no cases of CRPS.The overall complication rate for this procedure is high. Literature reports 5 cases of CRPS after 38 operations with the same implant (13%). We advise vitamin C as prophylaxis against CRPS in trapeziometacarpal joint replacement.

Are critical pathways and implant standardization programs effective in reducing costs in total knee replacement operations?

PubMed

Ho, David M; Huo, Michael H

2007-07-01

Total knee replacement (TKR) operation is one of the most effective procedures, both clinically and in terms of cost. Because of increased volume and cost for this procedure during the past 3 decades, TKRs are often targeted for cost reduction. The purpose of this study was to evaluate the efficacy of two cost reducing methodologies, establishment of critical clinical pathways, and standardization of implant costs. Ninety patients (90 knees) were randomly selected from a population undergoing primary TKR during a 2-year period at a tertiary teaching hospital. Patients were assigned to three groups that corresponded to different strategies implemented during the evolution of the joint-replacement program. Medical records were reviewed for type of anesthesia, operative time, length of stay, and any perioperative complications. Financial information for each patient was compared among the three groups. Data analysis demonstrated that the institution of a critical pathway significantly shortened length of hospital stay and was effective in reducing the hospital costs by 18% (p < 0.05). In addition, standardization of surgical techniques under the care of a single surgeon substantially reduced the operative time. Selection of implants from a single vendor did not have any substantial effect in additionally reducing the costs. Standardized postoperative management protocols and critical clinical pathways can reduce costs and operative time. Future efforts must focus on lowering the costs of the prostheses, particularly with competitive bidding or capitation of prostheses costs. Although a single-vendor approach was not effective in this study, it is possible that a cost reduction could have been realized if more TKRs were performed, because the pricing contract was based on projected volume of TKRs to be done by the hospital.

Outcome of Acute Prosthetic Joint Infections Due to Gram-Negative Bacilli Treated with Open Debridement and Retention of the Prosthesis▿

PubMed Central

Martínez-Pastor, Juan C.; Muñoz-Mahamud, Ernesto; Vilchez, Félix; García-Ramiro, Sebastián; Bori, Guillem; Sierra, Josep; Martínez, José A.; Font, Lluis; Mensa, Josep; Soriano, Alex

2009-01-01

The aim of our study was to evaluate the outcome of acute prosthetic joint infections (PJIs) due to gram-negative bacilli (GNB) treated without implant removal. Patients with an acute PJI due to GNB diagnosed from 2000 to 2007 were prospectively registered. Demographics, comorbidity, type of implant, microbiology data, surgical treatment, antimicrobial therapy, and outcome were recorded. Classification and regression tree analysis, the Kaplan-Meier survival method, and the Cox regression model were applied. Forty-seven patients were included. The mean age was 70.7 years, and there were 15 hip prostheses and 32 knee prostheses. The median number of days from the time of arthroplasty was 20. The most frequent pathogens were members of the Enterobacteriaceae family in 41 cases and Pseudomonas spp. in 20 cases. Among the Enterobacteriaceae, 14 were resistant to ciprofloxacin, while all Pseudomonas aeruginosa isolates were susceptible to ciprofloxacin. The median durations of intravenous and oral antibiotic treatment were 14 and 64 days, respectively. A total of 35 (74.5%) patients were in remission after a median follow-up of 463 days (interquartile range, 344 to 704) days. By use of the Kaplan-Meier survival curve, a C-reactive protein (CRP) concentration of ≤15 mg/dl (P = 0.03) and receipt of a fluoroquinolone, when all GNB isolated were susceptible (P = 0.0009), were associated with a better outcome. By use of a Cox regression model, a CRP concentration of ≤15 mg/dl (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.05 to 12.5; P = 0.043) and receipt of a fluoroquinolone (OR, 9.09; 95% CI, 1.96 to 50; P = 0.005) were independently associated with better outcomes. Open debridement without removal of the implant had a success rate of 74.5%, and the factors associated with good prognosis were a CRP concentration at the time of diagnosis ≤15 mg/dl and treatment with a fluoroquinolone. PMID:19687237

Detection of Prosthetic Hip Infection at Revision Arthroplasty by Immunofluorescence Microscopy and PCR Amplification of the Bacterial 16S rRNA Gene

PubMed Central

Tunney, Michael M.; Patrick, Sheila; Curran, Martin D.; Ramage, Gordon; Hanna, Donna; Nixon, James R.; Gorman, Sean P.; Davis, Richard I.; Anderson, Neil

1999-01-01

In this study the detection rates of bacterial infection of hip prostheses by culture and nonculture methods were compared for 120 patients with total hip revision surgery. By use of strict anaerobic bacteriological practice during the processing of samples and without enrichment, the incidence of infection by culture of material dislodged from retrieved prostheses after ultrasonication (sonicate) was 22%. Bacteria were observed by immunofluorescence microscopy in 63% of sonicate samples with a monoclonal antibody specific for Propionibacterium acnes and polyclonal antiserum specific for Staphylococcus spp. The bacteria were present either as single cells or in aggregates of up to 300 bacterial cells. These aggregates were not observed without sonication to dislodge the biofilm. Bacteria were observed in all of the culture-positive samples, and in some cases in which only one type of bacterium was identified by culture, both coccoid and coryneform bacteria were observed by immunofluorescence microscopy. Bacteria from skin-flake contamination were readily distinguishable from infecting bacteria by immunofluorescence microscopy. Examination of skin scrapings did not reveal large aggregates of bacteria but did reveal skin cells. These were not observed in the sonicates. Bacterial DNA was detected in 72% of sonicate samples by PCR amplification of a region of the bacterial 16S rRNA gene with universal primers. All of the culture-positive samples were also positive for bacterial DNA. Evidence of high-level infiltration either of neutrophils or of lymphocytes or macrophages into associated tissue was observed in 73% of patients. Our results indicate that the incidence of prosthetic joint infection is grossly underestimated by current culture detection methods. It is therefore imperative that current clinical practice with regard to the detection and subsequent treatment of prosthetic joint infection be reassessed in the light of these results. PMID:10488193

Outcome of acute prosthetic joint infections due to gram-negative bacilli treated with open debridement and retention of the prosthesis.

PubMed

Martínez-Pastor, Juan C; Muñoz-Mahamud, Ernesto; Vilchez, Félix; García-Ramiro, Sebastián; Bori, Guillem; Sierra, Josep; Martínez, José A; Font, Lluis; Mensa, Josep; Soriano, Alex

2009-11-01

The aim of our study was to evaluate the outcome of acute prosthetic joint infections (PJIs) due to gram-negative bacilli (GNB) treated without implant removal. Patients with an acute PJI due to GNB diagnosed from 2000 to 2007 were prospectively registered. Demographics, comorbidity, type of implant, microbiology data, surgical treatment, antimicrobial therapy, and outcome were recorded. Classification and regression tree analysis, the Kaplan-Meier survival method, and the Cox regression model were applied. Forty-seven patients were included. The mean age was 70.7 years, and there were 15 hip prostheses and 32 knee prostheses. The median number of days from the time of arthroplasty was 20. The most frequent pathogens were members of the Enterobacteriaceae family in 41 cases and Pseudomonas spp. in 20 cases. Among the Enterobacteriaceae, 14 were resistant to ciprofloxacin, while all Pseudomonas aeruginosa isolates were susceptible to ciprofloxacin. The median durations of intravenous and oral antibiotic treatment were 14 and 64 days, respectively. A total of 35 (74.5%) patients were in remission after a median follow-up of 463 days (interquartile range, 344 to 704) days. By use of the Kaplan-Meier survival curve, a C-reactive protein (CRP) concentration of < or = 15 mg/dl (P = 0.03) and receipt of a fluoroquinolone, when all GNB isolated were susceptible (P = 0.0009), were associated with a better outcome. By use of a Cox regression model, a CRP concentration of < or = 15 mg/dl (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.05 to 12.5; P = 0.043) and receipt of a fluoroquinolone (OR, 9.09; 95% CI, 1.96 to 50; P = 0.005) were independently associated with better outcomes. Open debridement without removal of the implant had a success rate of 74.5%, and the factors associated with good prognosis were a CRP concentration at the time of diagnosis < or = 15 mg/dl and treatment with a fluoroquinolone.

The Development of an Accelerometer System for Measuring Pelvic Motion During Walking.

DTIC Science & Technology

1979-01-01

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, T ASK AFIT STUDENT AT: University of Oxford CONTROLLING OFFICE NAME AND...bones, joints or muscles and physiotherapy to improve the functioning of impaired lower limbs. When irreparable damage occurs, the normal locomotor system...restoring near normal functioning of the locomotor system. Any improvement in surgical procedures, physiotherapy techniques, orthoses or prostheses

Application of computer graphics in the design of custom orthopedic implants.

PubMed

Bechtold, J E

1986-10-01

Implementation of newly developed computer modelling techniques and computer graphics displays and software have greatly aided the orthopedic design engineer and physician in creating a custom implant with good anatomic conformity in a short turnaround time. Further advances in computerized design and manufacturing will continue to simplify the development of custom prostheses and enlarge their niche in the joint replacement market.

Peak-picking fundamental period estimation for hearing prostheses.

PubMed

Howard, D M

1989-09-01

A real-time peak-picking fundamental period estimation device is described which is used in advanced hearing prostheses for the totally and profoundly deafened. The operation of the peak picker is compared with three well-established fundamental frequency estimation techniques: the electrolaryngograph, which is used as a "standard" hardware implementations of the cepstral technique, and the Gold/Rabiner parallel processing algorithm. These comparisons illustrate and highlight some of the important advantages and disadvantages that characterize the operation of these techniques. The special requirements of the hearing prostheses are discussed with respect to the operation of each device, and the choice of the peak picker is found to be felicitous in this application.

Success and complications of implant-retained prostheses provided by the Post-Doctoral Prosthodontics Program, University of Puerto Rico: a cross-sectional study.

PubMed

Loza-Herrero, María A; Rivas-Tumanyan, Sona; Morou-Bermudez, Evangelia

2015-11-01

The success rate of implant-retained prostheses in a postdoctoral prosthodontics program was unknown and could not be related to any set of potential clinical issues or patient characteristics. The purpose of this study was to determine the success rate of implant-retained prostheses placed by prosthodontic residents between 1997 and 2012 and to evaluate the associations between patient classifications and specific restoration characteristics as related to prosthesis success or failure. A total of 272 prostheses in 119 patients were clinically evaluated. Success was defined as the absence of prosthetic complications or any implant-related complication that affected prosthesis survival. Logistic regression was used to evaluate associations between prosthesis success/failure and a wide array of study variables, adjusting for patient age, sex, and prosthesis longevity. The overall success rate was 71%, with a mean prosthesis age of 4.5 years (range: 4 months to 16.8 years). Implant single crowns were the most successful prosthesis type (81% success). The most common complications observed were porcelain fractures in fixed dental prostheses (15%) and lack of stability (31%) and retention (29%) in removable dental prostheses. Having a removable prosthesis (versus natural dentition) in the opposing occlusion significantly decreased the odds of success (OR=0.26, 95% CI: 0.11-0.64). Definitively cemented fixed prostheses were more successful than those cemented with an interim cement (OR=4.56, 95% CI: 1.37-15.22). The overall success rate of the implant-retained prostheses placed in the program was low compared with previously published studies. This study revealed the need for an efficient, comprehensive recall system for patients receiving implant-retained prostheses, either fixed or removable. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Comparison of in vivo polyethylene wear particles between mobile- and fixed-bearing TKA in the same patients.

PubMed

Minoda, Yukihide; Hata, Kanako; Ikebuchi, Mitsuhiko; Mizokawa, Shigekazu; Ohta, Yoichi; Nakamura, Hiroaki

2017-09-01

Polyethylene wear particle generation is one of the most important factors that affects the mid- to long-term results of total knee arthroplasties (TKA). Mobile-bearing total knee prostheses were developed to reduce polyethylene wear generation. However, whether mobile-bearing prostheses actually generate fewer polyethylene wear particles than fixed-bearing prostheses remains controversial. The aim of this study was to compare, within individual patients, the in vivo polyethylene wear particles created by a newly introduced mobile-bearing prosthesis in one knee and a conventional fixed-bearing prosthesis in other knee. Eighteen patients receiving bilateral TKAs to treat osteoarthritis were included. The synovial fluid was obtained from 36 knees at an average of 3.5 years after the operation. The in vivo polyethylene wear particles were isolated from the synovial fluid using a previously validated method and examined using a scanning electron microscope and an image analyser. The size and shape of the polyethylene wear particles from the mobile-bearing prostheses were similar to those from the conventional fixed-bearing prostheses. Although the number of wear particles from the mobile-bearing prosthesis (1.63 × 10 7  counts/knee) appeared smaller than that from the fixed-bearing prosthesis (2.16 × 10 7  counts/knee), the difference was not statistically significant. The current in vivo study shows that no statistically significant differences were found between the polyethylene wear particles generated by a newly introduced mobile-bearing PS prosthesis and a conventional fixed-bearing PS prosthesis during the early clinical stage after implantation. Therapeutic study, Level III.

The influence of resting periods on friction in the artificial hip.

PubMed

Nassutt, Roman; Wimmer, Markus A; Schneider, Erich; Morlock, Michael M

2003-02-01

Insufficient tribologic performance of total joint components is a major cause of prostheses failure. Wear has been studied intensively using testing machines that apply continuous motions. Human locomotion, however, is not well represented by continuous motions alone. Singular events and resting periods are a substantial part of daily activities. Resting does influence adhesion in the artificial joint with possible effects on friction, wear, and loosening. The current study evaluated the effects of resting on the frictional properties of hip prosthesis components. The activity measurements of 32 patients with artificial hip replacements were analyzed for resting durations of the hip. A pin-on-ball screening device was used to determine friction after characteristic resting periods and during continuous oscillating motion. All common articulation pairings were investigated. Prolonged and frequent resting periods of the hip were found for the patients. Initial friction increased with increasing resting duration for all tested materials (between 41% and 191%). The metal-on-metal articulations showed the highest friction level (0.098 for sliding) and the highest increase (191%) in friction with resting duration (0.285 after resting periods of 60 seconds). A high static frictional moment after resting periods might present a risk for aseptic implant loosening. Therefore, large head diameters of metal-on-metal joints should be used with caution, especially when additional unfavorable risk factors such as obesity, weak bone-implant interface, or high activity level are present.

Tribo-electrochemical characterization of metallic biomaterials for total joint replacement.

PubMed

Diomidis, N; Mischler, S; More, N S; Roy, Manish

2012-02-01

Knee and hip joint replacement implants involve a sliding contact between the femoral component and the tibial or acetabular component immersed in body fluids, thus making the metallic parts susceptible to tribocorrosion. Micro-motions occur at points of fixation leading to debris and ion release by fretting corrosion. β-Titanium alloys are potential biomaterials for joint prostheses due to their biocompatibility and compatibility with the mechanical properties of bone. The biotribocorrosion behavior of Ti-29Nb-13Ta-4.6Zr was studied in Hank's balanced salt solution at open circuit potential and at an applied potential in the passive region. Reciprocating sliding tribocorrosion tests were carried out against technical grade ultra high molecular weight polyethylene, while fretting corrosion tests were carried out against alumina. The wear of the alloy is insignificant when sliding against polyethylene. However, depassivation does take place, but the tested alloy showed an ability to recover its passive state during sliding. The abrasivity of the alloy depends on the electrochemical conditions of the contact, while the wear of polyethylene proceeds through third body formation and material transfer. Under fretting corrosion conditions recovery of the passive state was also achieved. In a fretting contact wear of the alloy proceeds through plastic deformation of the bulk material and wear resistance depends on the electrochemical conditions. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

PubMed Central

2013-01-01

Background Ceramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant. Methods A five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion. Results The implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate. Conclusions It is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices. PMID:23988155

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants.

PubMed

Turger, Anke; Köhler, Jens; Denkena, Berend; Correa, Tomas A; Becher, Christoph; Hurschler, Christof

2013-08-29

Ceramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant. A five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion. The implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate. It is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.

Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis.

PubMed

Stengel, Dirk; Bauwens, Kai; Ekkernkamp, Axel; Cramer, Jörg

2005-03-01

The reputation of total ankle arthroplasty for treating end-stage ankle arthritis of different origin is dubious. Newer generation meniscal-bearing prostheses may have overcome the known problems with earlier implants. There is, however, no systematic approach to the available scientific evidence allowing for a critical appraisal of their benefits and risks. We conducted a systematic review meta-analysis of studies exploring the efficacy of three-component total ankle prostheses. We demanded a minimum sample size of 20 subjects, at least 1 year of follow-up, and a clinically relevant study endpoint (for example, results of ankle scoring, ranges of motion [ROM], complications, and survival rates). We identified citations by electronic medical databases and a manual search. We made no restrictions for language. We used an eight-point quality scale to appraise methodological standards, and modeled outcomes by random-effects meta-regression analysis. Eighteen of 1830 citations including 1086 patients fulfilled our eligibility criteria. Studies met a median of four quality items (interquartile range 2-5). Outcome estimates did not depend on methodological quality. There was no evidence of strong heterogeneity or publication bias. With standardized 100-point ankle and hindfoot scores, formal data pooling was possible for 10 trials (n =497), showing a mean improvement of 45.2 points (95% confidence interval [CI] 39.3-51.1). Overall ROM improved slightly (6.3 degrees, 95%CI 2.2-10.5 degrees ). Weighted complication rates ranged from 1.6% (deep infections) to 14.7% (impingement). Secondary surgery had to be performed in 12.5%, whereas secondary arthrodesis was necessary in 6.3%. The weighted 5-year prosthesis survival rate averaged 90.6%. Ankle arthroplasty improves pain and joint mobility in end-stage ankle arthritis. Its performance in comparison to the current reference standard (that is, ankle fusion) remains to be defined in a properly designed randomized trial.

Impact of mandibular implant prostheses on the oral health-related quality of life in partially and completely edentulous patients.

PubMed

Yunus, Norsiah; Masood, Mohd; Saub, Roslan; Al-Hashedi, Ashwaq Ali; Taiyeb Ali, Tara Bai; Thomason, John Mark

2016-07-01

To assess the oral health-related quality of life (OHRQoL) of patients provided with mandibular implant fixed partial prostheses (IFPP) for rehabilitation of two adjacent missing posterior teeth and complete denture patients provided with mandibular implant-supported overdenture (ISOD). The response to change in OHRQoL with implant prostheses was additionally compared. In this prospective study, 20 IFPP (mean age 47.0; SD 12.9 years) and 28 ISOD (mean age 61.5; SD 9.1 years) patients received 2 mandibular implants. Metal ceramic nonsplinted fixed prostheses were provided in IFPP group, while in ISOD group, the mandibular overdentures were retained by nonsplinted attachments. Patients rated their oral health-related quality of life using OHIP-14 Malaysian version at baseline (T0), 2-3 months (T1) and 1 year (T2) postimplant treatment. Mean OHIP-14 for total and domain scores between groups and intervals was analysed using repeated-measures ANOVA and t-test. Mann-Whitney and Wilcoxon signed-rank tests were used for the comparison of mean score change and effect size, while the association between pre- and post-treatment scores was determined using multivariate linear regression modelling. The total OHIP and domain scores before implant treatment were significantly higher (lower OHRQoL) in IFPP than in ISOD groups, except for physical pain where this domain showed similar impact in both groups. Postimplant scores between groups at T1 and T2 showed no significant difference. The mean score changes at T0-T1 and T0-T2 for total OHIP-14 and domains were significantly greater in IFPP except in the domains of physical pain and disability which showed no difference. Large effect size (ES) was observed for total OHIP-14 in IFPP while moderate in ISOD. Improved OHRQoL was dependent on the treatment group and pretreatment score. Improvement in OHRQoL occurred following both mandibular implant-supported overdentures and implant fixed partial prostheses. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Oral health and oral implant status in edentulous patients with implant-supported dental prostheses who are receiving long-term nursing care.

PubMed

Isaksson, Rita; Becktor, Jonas P; Brown, Andrew; Laurizohn, Christer; Isaksson, Sten

2009-12-01

The aim of this study was to investigate oral health and oral implant status in a group of edentulous patients receiving long-term residential or nursing care (LTC), all of whom had implant-supported fixed or removable dental prostheses. A dental examination was performed on a total of 3310 patients receiving LTC and from this population 35 edentulous patients in whom dental implants had been placed formed the cohort for this study. All examinations were performed by a specialist in hospital dentistry and took place in the patients' own home environment. Oral health was assessed by means of a protocol which evaluated oral hygiene status, possible oral mucosal inflammation and oral mucosal friction levels. Any problems with the implant-supported prosthesis, implant mobility or other complications were also assessed. In addition, patients were asked about any oral symptoms and their usual oral hygiene procedures. About half of the subjects (17/35) were registered as having no/mild inflammation with 18 of 35 having moderate/severe inflammation. Twelve of the 35 patients had good/acceptable oral hygiene and 23 of 35 had poor/bad oral hygiene. Twenty-one of the 35 patients depended on help from the nursing personnel for their daily oral hygiene procedures. Obvious problems with food impaction were noted in 11 patients. A total of 229 implants had been placed in 43 jaws supporting 40 full arch-fixed prostheses and three implant-borne overdentures. There was no evidence of mobility or fractures of either the implants or the prostheses. Fifteen implants showed some exposed screw threads. Pus was exuding from one implant site and general peri-implant gingival hyperplasia was noted in two patients. Twenty-four patients were completely satisfied with the function and appearance of their implant-supported prostheses. Two patients were totally dissatisfied. This study indicates that oral implant therapy can be considered as a treatment of choice in elderly patients, even if oral hygiene is sub-optimal.

Spectral components in electromyograms from four regions of the human masseter, in natural dentate and edentulous subjects with removable prostheses and implants.

PubMed

Guzmán-Venegas, Rodrigo A; Palma, Felipe H; Biotti P, Jorge L; de la Rosa, Francisco J Berral

2018-06-01

To compare the frequency or spectral components between different regions of the superficial masseter in young natural dentate and total edentulous older adults rehabilitated with removable prostheses and fixed-implant support. A secondary objective was to compare these components between the three groups. 21 young natural dentate and 28 edentulous (14 with removable prostheses and 14 with fixed-implant support) were assessed. High-density surface electromyography (sEMG) was recorded in four portions of the superficial masseter during submaximal isometric bites. Spectral components were obtained through a spectral analysis of the sEMG signals. An analysis of mixed models was used to compare the spectral components. In all groups, the spectral components of the anterior portion were lower than in the posterior region (p < 0.05). Both edentulous groups showed lower spectral components and median frequency slope than the natural dentate group (p < 0.05). The removable prostheses group showed the greatest differences with natural dentate group. There were significant differences in the spectral components recorded in the different regions of the superficial masseter. The lower spectral components and fatigability of older adults rehabilitated with prostheses could be a cause of a greater loss of type II fibers, especially in the removable prostheses group. Copyright © 2018 Elsevier Ltd. All rights reserved.

Total Knee Replacement

PubMed Central

2005-01-01

Executive Summary Objective The aim of this review was to assess the effectiveness, in terms of pain reduction and functional improvement, and costing of total knee replacement (TKR) for people with osteoarthritis for whom less invasive treatments (such as physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids, hyaluronic acids, and arthroscopic surgery) have failed. Clinical Need Osteoarthritis affects an estimated 10% to 12% of Canadian adults. The therapeutic goals of osteoarthritis treatment are to improve joint mobility and reduce pain. Stepwise treatment options include exercise, weight loss, physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids and hyaluronic acids, arthroscopic surgery, and, in severe cases, total joint replacement with follow-up rehabilitation. These treatments are delivered by a range of health care professionals, including physiotherapists, occupational therapists, family physicians, internists, rheumatologists, and orthopedic surgeons. TKR is an end-of-line treatment for patients with severe pain and functional limitations. More women than men undergo knee replacement, and most patients are between 55 and 84 years old. The Technology TKR is a surgical procedure in which an artificial joint or prosthesis replaces a damaged knee joint. The primary indication for TKR is pain, followed by functional limitation. Usually, a person’s daily activities must be substantially affected by pain and functional limitations for him or her to be considered a candidate for TKR. There are 3 different types of knee replacement prostheses. Non-constrained prostheses use the patient’s ligaments and muscles to provide the stability for the prosthesis. Semi-constrained prostheses provide some stability for the knee and do not rely entirely on the patient’s ligaments and muscles to provide the stability. Constrained prostheses are for patients whose ligaments and muscles are not able to provide stability for the knee prosthesis. The most common risks and complications associated with TKR are deep venous thrombosis, infection, stiffness, loosening, and osteolysis. To prevent deep venous thrombosis, patients are treated with heparin prophylactically and/or given support stockings to wear. Patients are also given antibiotics for 24 hours after surgery to minimize the risk of infection. Stiffness is another associated complication. In most patients, it can be avoided by keeping the knee moving in the days and weeks following surgery. The National Institutes of Health in the United States concluded that the indications for TKR should include the following: radiological evidence of joint damage, moderate to severe persistent pain that is not adequately relieved by nonsurgical management, and clinically significant functional limitation resulting in diminished quality of life. Review Strategy In March 2005, the following databases were searched: Cochrane Library International Agency for Health Technology Assessment (first quarter 2005), Cochrane Database of Systematic Reviews (first quarter 2005), Cochrane Central Register of Controlled Trials (first quarter 2005), MEDLINE (1966 to March 2005), MEDLINE In-Process and Other Non-indexed Citations (1966 to March 14, 2005), and EMBASE (1980 to 2005 week 9). The Medical Advisory Secretariat also searched Medscape on the Internet for recent reports on trials that were unpublished but that were presented at international conferences. In addition, the Web site Current Controlled Trials (www.controlled-trials.com) was searched for ongoing trials investigating TKR or unicompartmental knee replacement. No studies were identified that compared TKR to an alternative treatment. Several studies have been reported that compare preoperative measurement scores on targeted measures of functioning and pain to postoperative measurement scores in patients undergoing various TKR procedures. In order for the Medical Advisory Secretariat to measure the effectiveness of TKR and to compare the effectiveness of TKR across studies, effect sizes were calculated in studies that reported the standard deviations of the preoperative and postoperative measurement scores. Percent change was also calculated. For this review, a 20% improvement in outcome score was defined as the minimal clinically important difference. Summary of Findings Overall, patients who undergo TKR surgery for osteoarthritis have substantial improvements in terms of reduction of pain and improvement of function. A comparison of the mean effect score and the percent change in 19 studies that reported preoperative and postoperative outcome scores for patients who had TKR showed that the procedure is effective. The 19 studies included patients of various ages and used a variety of prostheses and techniques to implant the device. TKR was effective in all of the studies. The revision rates ranged from 0% to 13% in the studies that reported at least 5 years of follow-up. As for the factors that predict TKR outcomes, a variety of factors have been evaluated, including obesity, age, gender, prosthesis design, and surgical techniques; however, none of these have been shown to predict outcomes (pain or function) consistently across studies. However, the regression analyses identified accounted for only 12% to 27% of the variance, indicating that over 70% of the variance in the outcomes of TKR is unexplained. In terms of the timing of TKR surgery, 2 studies found that the severity of osteoarthritis does not predict outcome, but 1 study was found that higher functioning patients had significantly less pain and better function up to 2 years after surgery compared with lower functioning patients. It is important to note that the patients in the low and high function groups were evenly matched on comorbid conditions. Unicompartmental knee replacement surgery seems to be as effective as TKR surgery for people who meet the indications for it. This is a subset of people who have osteoarthritis of the knee, because for unicompartmental knee replacement to be indicated, only 1 (usually the medial) compartment of the knee can be affected. Patients who undergo this kind of surgery seem to have shorter hospital stays and faster recovery times than do patients who have TKR surgery. Conclusion There is substantial evidence to indicate that TKR effectively reduces pain and improves function. PMID:23074478

Exploiting arm posture synergies in activities of daily living to control the wrist rotation in upper limb prostheses: A feasibility study.

PubMed

Montagnani, Federico; Controzzi, Marco; Cipriani, Christian

2015-01-01

Although significant technological advances have been made in the last forty years, natural and effortless control of upper limb prostheses is still an open issue. Commercially available myoelectric prostheses present limited Degrees of Freedom (DoF) mainly because of the lack of available and reliable independent control signals from the human body. Thus, despite the crucial role that an actuated wrist could play in a transradial prosthesis in terms of avoiding compensatory movements, commercial hand prostheses present only manually adjustable passive wrists or actuated rotators controlled by (unnatural) sequential control strategies. In the present study we investigated the synergies between the humeral orientation with respect to the trunk and the forearm pronation/supination angles during the execution of a wide range of activities of daily living, in healthy subjects. Our results showed consistent postural synergies between the two selected body segments for almost the totality of the activities of daily living under investigation. This is a promising result because these postural synergies could be exploited to automatically control the wrist rotator unit in transradial prostheses improving the fluency and the dexterity of the amputee.

Biofilms in periprosthetic orthopedic infections

PubMed Central

McConoughey, Stephen J; Howlin, Rob; Granger, Jeff F; Manring, Maurice M; Calhoun, Jason H; Shirtlif, Mark; Kathju, Sandeep; Stoodley, Paul

2015-01-01

As the number of total joint arthroplasty and internal fixation procedures continues to rise, the threat of infection following surgery has significant clinical implications. These infections may have highly morbid consequences to patients, who often endure additional surgeries and lengthy exposures to systemic antibiotics, neither of which are guaranteed to resolve the infection. Of particular concern is the threat of bacterial biofilm development, since biofilm-mediated infections are difficult to diagnose and effective treatments are lacking. Developing therapeutic strategies have targeted mechanisms of biofilm formation and the means by which these bacteria communicate with each other to take on specialized roles such as persister cells within the biofilm. In addition, prevention of infection through novel coatings for prostheses and the local delivery of high concentrations of antibiotics by absorbable carriers has shown promise in laboratory and animal studies. Biofilm development, especially in an arthoplasty environment, and future diagnostic and treatment options are discussed. PMID:25302955

CKS knee prosthesis: biomechanics and clinical results in 42 cases.

PubMed

Martucci, E; Verni, E; Del Prete, G; Stulberg, S D

1996-01-01

From 1991 to 1993 a total of 42 CKS prostheses were implanted for the following reasons: osteoarthrosis (34 cases), rheumatoid arthritis (7 cases) tibial necrosis (1 case). At follow-up obtained after 17 to 41 months the results were: excellent or good: 41; the only poor result was probably related to excessive tension of the posterior cruciate ligament. 94% of the patients reported complete regression of pain, 85% was capable of going up and down stairs without support. Mean joint flexion was 105 degrees. Radiologically the anatomical axis of the knee had a mean valgus of anatomical axis of the knee had a mean valgus of 6 degrees. The prosthetic components were always cemented. The posterior cruciate ligament was removed in 7 knees, so that the prosthesis with "posterior stability" was used. The patella was never prosthetized. One patient complained of peri-patellar pain two months after surgery which then regressed completely.

Long-term results of uncemented alumina acetabular implants.

PubMed

Boehler, M; Knahr, K; Plenk, H; Walter, A; Salzer, M; Schreiber, V

1994-01-01

We report the clinical and tribological performance of 67 ceramic acetabular prostheses implanted between 1976 and 1979 without bone cement. They articulated with ceramic femoral heads mounted on mental femoral stems. After a mean elapsed period of 144 months, 59 sockets were radiographically stable but two showed early signs and six showed late signs of loosening. Four of the loose sockets have been revised. Histological analysis of the retrieved tissue showed a fibrous membrane around all the implants, with fibrocartilage in some. There was no bone ingrowth, and the fibrous membrane was up to 6 mm thick and infiltrated with lymphocytes, plasma cells, and macrophages. Intra- and extracellular birefringent wear particles were seen. Tribological analysis showed total wear rates in two retrieved alumina-on-alumina joints of 2.6 microns per year in a stable implant and 68 microns in a loose implant. Survival analysis showed a revision rate of 12.4% at 136 months.

Gait asymmetry of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees.

PubMed

Kaufman, Kenton R; Frittoli, Serena; Frigo, Carlo A

2012-06-01

Amputees walk with an asymmetrical gait, which may lead to future musculoskeletal degenerative changes. The purpose of this study was to compare the gait asymmetry of active transfemoral amputees while using a passive mechanical knee joint or a microprocessor-controlled knee joint. Objective 3D gait measurements were obtained in 15 subjects (12 men and 3 women; age 42, range 26-57). Research participants were longtime users of a mechanical prosthesis (mean 20 years, range 3-36 years). Joint symmetry was calculated using a novel method that includes the entire waveform throughout the gait cycle. There was no significant difference in hip, knee and ankle kinematics symmetry when using the different knee prostheses. In contrast, the results demonstrated a significant improvement in lower extremity joint kinetics symmetry when using the microprocessor-controlled knee. Use of the microprocessor-controlled knee joint resulted in improved gait symmetry. These improvements may lead to a reduction in the degenerative musculoskeletal changes often experienced by amputees. Copyright © 2011 Elsevier Ltd. All rights reserved.

Single stage treatment of ankylosis of the temporomandibular joint using patient-specific total joint replacement and virtual surgical planning.

PubMed

Haq, Jahrad; Patel, Nishma; Weimer, Katherine; Matthews, N Shaun

2014-04-01

Ankylosis of the temporomandibular joint (TMJ) is a debilitating condition that can result in pain, trismus, and a poor quality of life. It can be caused by injury, infection, and rheumatoid disease. Current management includes gap arthroplasty, interpositional arthroplasty, and reconstruction. Traditionally, joints are reconstructed using stock implants, or the procedure is done in two stages with an additional computed tomography (CT) scan between the resective and reconstructive procedures and use of stereolithographic models to aid the design of the definitive prostheses. We describe a technique for the resection of ankylosis and reconstruction of the joint in a single operation using virtually designed custom-made implants. Five patients with ankylosis of the TMJ had a single stage operation with reconstruction between 2010 and 2012. All had preoperative high-resolution CT with contrast angiography. During an international web-based teleconference between the surgeon and the engineer a virtual resection of the ankylosis was done using the reconstructed CT images. The bespoke cutting guides and implants were designed virtually at the same time and were then manufactured precisely using computer-aided design and manufacture (CAD-CAM) over 6 weeks. After release of the ankylosis and reconstruction, the patients underwent an exercise regimen to improve mouth opening. Follow-up was for a minimum of 6 months. Four patients had one operation, and one patient had two. Median/Mean maximum incisal opening increased from 0.6mm before operation to 25 mm afterwards (range 23-27), and there was minimal surgical morbidity. This new method effectively treats ankylosis of the TMJ in a single stage procedure. Fewer operations and hospital stays, and the maintenance of overall clinical outcome are obvious advantages. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Whole-body angular momentum during stair walking using passive and powered lower-limb prostheses.

PubMed

Pickle, Nathaniel T; Wilken, Jason M; Aldridge, Jennifer M; Neptune, Richard R; Silverman, Anne K

2014-10-17

Individuals with a unilateral transtibial amputation have a greater risk of falling compared to able-bodied individuals, and falling on stairs can lead to serious injuries. Individuals with transtibial amputations have lost ankle plantarflexor muscle function, which is critical for regulating whole-body angular momentum to maintain dynamic balance. Recently, powered prostheses have been designed to provide active ankle power generation with the goal of restoring biological ankle function. However, the effects of using a powered prosthesis on the regulation of whole-body angular momentum are unknown. The purpose of this study was to use angular momentum to evaluate dynamic balance in individuals with a transtibial amputation using powered and passive prostheses relative to able-bodied individuals during stair ascent and descent. Ground reaction forces, external moment arms, and joint powers were also investigated to interpret the angular momentum results. A key result was that individuals with an amputation had a larger range of sagittal-plane angular momentum during prosthetic limb stance compared to able-bodied individuals during stair ascent. There were no significant differences in the frontal, transverse, or sagittal-plane ranges of angular momentum or maximum magnitude of the angular momentum vector between the passive and powered prostheses during stair ascent or descent. These results indicate that individuals with an amputation have altered angular momentum trajectories during stair walking compared to able-bodied individuals, which may contribute to an increased fall risk. The results also suggest that a powered prosthesis provides no distinct advantage over a passive prosthesis in maintaining dynamic balance during stair walking. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of intraoperative soft tissue balance on patellar pressure in posterior-stabilized total knee arthroplasty.

PubMed

Matsumoto, Tomoyuki; Shibanuma, Nao; Takayama, Koji; Sasaki, Hiroshi; Ishida, Kazunari; Matsushita, Takehiko; Kuroda, Ryosuke; Kurosaka, Masahiro

2016-06-01

Appropriate soft tissue balance is essential for the success of total knee arthroplasty (TKA), and assessment with an offset-type tensor provides useful information about the femorotibial (FT) joint. The purpose of the study was to investigate the relationship between intraoperative soft tissue balance and patellar pressure at both medial and lateral sides. Thirty varus-type osteoarthritis patients who received mobile-bearing posterior-stabilized TKAs were enrolled in the study. Using the tensor, soft tissue balance, including joint component gap and varus ligament balance, was recorded at 0°, 10°, 30°, 60°, 90°, 120°, and 135° with patellofemoral (PF) joint reduction and femoral component placement. Following final prostheses implanted with appropriate insert, the medial and lateral patellar pressures were measured at each flexion angle. A simple regression analysis was performed between each patellar pressure, parameter of soft tissue balance, and postoperative flexion angle. Both lateral and medial patellar pressures increased with flexion. The lateral patellar pressure was significantly higher than the medial patellar pressure at 60°, 90°, and 135° of flexion (p<0.05). The lateral patellar pressure inversely correlated with the varus ligament balance at 60° and 90° of flexion (p<0.05). The lateral patellar pressure at 120° and 135° of flexion inversely correlated with the postoperative flexion angle (p<0.05). Soft tissue balance influenced patellar pressure. In particular, a reduced lateral patellar pressure was found at the lateral laxity at flexion, leading to high postoperative flexion angle. III. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of posterior tibial slope on knee flexion in posterior-stabilized total knee arthroplasty.

PubMed

Shi, Xiaojun; Shen, Bin; Kang, Pengde; Yang, Jing; Zhou, Zongke; Pei, Fuxing

2013-12-01

To evaluate and quantify the effect of the tibial slope on the postoperative maximal knee flexion and stability in the posterior-stabilized total knee arthroplasty (TKA). Fifty-six patients (65 knees) who had undergone TKA with the posterior-stabilized prostheses were divided into the following 3 groups according to the measured tibial slopes: Group 1: ≤4°, Group 2: 4°-7° and Group 3: >7°. The preoperative range of the motion, the change in the posterior condylar offset, the elevation of the joint line, the postoperative tibiofemoral angle and the preoperative and postoperative Hospital for Special Surgery (HSS) scores were recorded. The tibial anteroposterior translation was measured using the Kneelax 3 Arthrometer at both the 30° and the 90° flexion angles. The mean values of the postoperative maximal knee flexion were 101° (SD 5), 106° (SD 5) and 113° (SD 9) in Groups 1, 2 and 3, respectively. A significant difference was found in the postoperative maximal flexion between the 3 groups (P < 0.001). However, no significant differences were found between the 3 groups in the postoperative HSS scores, the changes in the posterior condylar offset, the elevation of the joint line or the tibial anteroposterior translation at either the 30° or the 90° flexion angles. A 1° increase in the tibial slope resulted in a 1.8° flexion increment (r = 1.8, R (2) = 0.463, P < 0.001). An increase in the posterior tibial slope can significantly increase the postoperative maximal knee flexion. The tibial slope with an appropriate flexion and extension gap balance during the operation does not affect the joint stability.

Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide

PubMed Central

Rocha, Magda F.G.; Mansur, Alexandra A.P.; Martins, Camila P.S.; Barbosa-Stancioli, Edel F.; Mansur, Herman S.

2010-01-01

Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level of oxidation (Iox) characterized by Fourier Transformed Infrared Spectroscopy (FTIR). The potential inflammatory response, cell viability and biocompatibility of such oxidized UHMWPE systems were assessed by a novel biological in vitro assay based on the secretion of nitric oxide (NO) by activated murine macrophages with gamma interferon (IFN-γ) cytokine and lipopolysaccharide (LPS). Furthermore, macrophage morphologies in contact with UHMWPE oxidized surfaces were analyzed by cell spreading-adhesion procedure using scanning electron microscopy (SEM). The results have given significant evidence that the longer the period of accelerated aging of UHMWPE the higher was the macrophage inflammatory equivalent response based on NO secretion analysis. PMID:20721321

Clinical and Radiographic Assessment of Reasons for Replacement of Metal- Ceramic Fixed Dental Prostheses in Patients Referring to Dental School.

PubMed

Al Refai, Roa'a; Saker, Samah

2018-01-01

The expected length of service and reasons for fixed dental prostheses (FDPs) replacement are a frequent inquiry by patients while the answers were mainly based on studies reports that was conducted outside the middle east region. This clinical and radiographic survey was constructed to assess and survey clinically and radiographically the reasons of replacement of metal-ceramic fixed dental prostheses, amongst patients reporting at dental school in Taibah University. Between January and May 2016, 151 patients were recruited for this study. Interview (include questions pertained to the length of service of the prosthesis, the nature of complaint as told by patient in her own words), clinical examination, intra-oral photographs, and periapical radiographs, were done by the researchers. The parameters assessed were secondary caries, open margins, loss of retention, failure of endodontic treatment of the abutment and periodontal diseases. A total number of 249 failed fixed dental prostheses were evaluated. Of which 180 (39.7%) were single crowns, 159 (35.0%) were retainers and 117 (25.8%) were pontics in 69 fixed partial denture. The most common reason for replacement of fixed restorations was periodontal diseases affecting 92.8% of all types' restorations, followed by defective margin in 90.4% of examined restoration, poor aesthetic in 88% of restorations, while periapical involvement was found in 85.5% of fixed dental prosthesis. The survival rates of fixed prostheses were not predictable, and no association was found between number of years in service and the number of restorations. The most common reasons for replacing single unit fixed dental prostheses are periodontal diseases and periapical involvement, while defective margins and poor aesthetic mainly associated with multi-unit fixed dental prostheses. Key words: Failure, Fixed dental prosthesis, Survival, Replacement.

Adaptive sports ankle prosthetics. Interview by Sarah A. Curran.

PubMed

Lyle, David K

2012-09-01

Participating in sport at all levels is gaining a dedicated following and this is also apparent in individuals with an amputation. Currently, there is a wide variety of ankle prostheses available which attempt to provide function, control, and comfort, as well as good aesthetic appeal. Participation in sport, however, increases the demands placed upon ankle prostheses. This can compromise function and performance, and constrain the opportunities of participation in various outdoor and water sports. In acknowledging this limitation and the need to develop more versatile ankle prostheses, this article introduces the evolution of a prototype ankle prosthesis referred to as "Adaptive Sports Ankle." The ankle prosthesis, which is compatible with any foot pyramid adapter, offers the same range of motion as the normal human ankle joint and is made up of components that are chemical and corrosion resistant. These design features that are specifically created to accommodate below-the-knee amputees provide an ideal prosthesis for those wishing to lead an active lifestyle and participate in aquatic (i.e. swimming, surfing, and scuba diving), snowboarding, and equestrian activities. Although it is acknowledged that there is a need to establish research on the Adaptive Sports Ankle, its introduction to the market will enhance and expand opportunities of those individuals with a lower limb amputation to lead an active and healthy lifestyle.

Detection of total knee prostheses at airport security checkpoints.

PubMed

Naziri, Qais; Johnson, Aaron J; Hooper, Hasan A; Sana, Said H; Mont, Michael A

2012-06-01

Airport security screening measures have changed substantially during the past decade, but few reports have examined how this affects patients who have undergone knee arthroplasties. The purpose of this study was to characterize the efficacy of airport metal detection of total knee prostheses, the delays faced, any inconvenience this may have caused, and the role of implant identification cards. Ninety-seven total knee arthroplasty recipients reported passing through an airport metal detector, with 70 triggering the alarm a mean of 3 times (range, 1-36). The presence of a single-knee prosthesis triggered airport security alarms more than 83% of the time and increased patient inconvenience. Patients should be informed about this chance and be prepared to present documentation of their prosthesis. Copyright © 2012 Elsevier Inc. All rights reserved.

Multifunctional Coatings to Simultaneously Promote Osseointegration and Prevent Infection of Orthopaedic Implants

PubMed Central

Raphel, Jordan; Holodniy, Mark; Goodman, Stuart B.; Heilshorn, Sarah C.

2016-01-01

The two leading causes of failure for joint arthroplasty prostheses are aseptic loosening and periprosthetic joint infection. With the number of primary and revision joint replacement surgeries on the rise, strategies to mitigate these failure modes have become increasingly important. Much of the recent work in this field has focused on the design of coatings either to prevent infection while ignoring bone mineralization or vice versa, to promote osseointegration while ignoring microbial susceptibility. However, both coating functions are required to achieve long-term success of the implant; therefore, these two modalities must be evaluated in parallel during the development of new orthopaedic coating strategies. In this review, we discuss recent progress and future directions for the design of multifunctional orthopaedic coatings that can inhibit microbial cells while still promoting osseointegration. PMID:26851394

Complete denture analyzed by optical coherence tomography

NASA Astrophysics Data System (ADS)

Negrutiu, Meda L.; Sinescu, Cosmin; Todea, Carmen; Podoleanu, Adrian G.

2008-02-01

The complete dentures are currently made using different technologies. In order to avoid deficiencies of the prostheses made using the classical technique, several alternative systems and procedures were imagined, directly related to the material used and also to the manufacturing technology. Thus, at the present time, there are several injecting systems and technologies on the market, that use chemoplastic materials, which are heat cured (90-100°C), in dry or wet environment, or cold cured (below 60°C). There are also technologies that plasticize a hard cured material by thermoplastic processing (without any chemical changes) and then inject it into a mold. The purpose of this study was to analyze the existence of possible defects in several dental prostheses using a non invasive method, before their insertion in the mouth. Different dental prostheses, fabricated from various materials were investigated using en-face optical coherence tomography. In order to discover the defects, the scanning was made in three planes, obtaining images at different depths, from 0,01 μm to 2 mm. In several of the investigated prostheses we found defects which may cause their fracture. These defects are totally included in the prostheses material and can not be vizualised with other imagistic methods. In conclusion, en-face OCT is an important investigative tool for the dental practice.

Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

PubMed

Dumas, R; Cheze, L

2008-08-01

Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses.

Dose-dependent cytotoxicity evaluation of graphite nanoparticles for diamond-like carbon film application on artificial joints.

PubMed

Liao, T T; Deng, Q Y; Wu, B J; Li, S S; Li, X; Wu, J; Leng, Y X; Guo, Y B; Huang, N

2017-01-24

While a diamond-like carbon (DLC)-coated joint prosthesis represents the implant of choice for total hip replacement in patients, it also leads to concern due to the cytotoxicity of wear debris in the form of graphite nanoparticles (GNs), ultimately limiting its clinical use. In this study, the cytotoxicity of various GN doses was evaluated. Mouse macrophages and osteoblasts were incubated with GNs (<30 nm diameter), followed by evaluation of cytotoxicity by means of assessing inflammatory cytokines, results of alkaline phosphatase assays, and related signaling protein expression. Cytotoxicity evaluation showed that cell viability decreased in a dose-dependent manner (10-100 μg ml -1 ), and steeply declined at GNs concentrations greater than 30 μg ml -1 . Noticeable cytotoxicity was observed as the GN dose exceeded this threshold due to upregulated receptor of activator of nuclear factor kB-ligand expression and downregulated osteoprotegerin expression. Meanwhile, activated macrophage morphology was observed as a result of the intense inflammatory response caused by the high doses of GNs (>30 μg ml -1 ), as observed by the increased release of TNF-α and IL-6. The results suggest that GNs had a significant dose-dependent cytotoxicity in vitro, with a lethal dose of 30 μg ml -1 leading to dramatic increases in cytotoxicity. Our GN cytotoxicity evaluation indicates a safe level for wear debris-related arthropathy and could propel the clinical application of DLC-coated total hip prostheses.

Primary total hip arthroplasty in Catalonia: What is the clinical evidence that supports our prosthesis?

PubMed

Chaverri-Fierro, D; Lobo-Escolar, L; Espallargues, M; Martínez-Cruz, O; Domingo, L; Pons-Cabrafiga, M

The implementation of National Prostheses Registries allows us to obtain a large amount of data and make conclusions in order to improve the use of them. Sweden was the first country to implement a National Prostheses Registry in 1979. Catalonia has been doing this since 2005. The aim of our study is to analyse the evidence that supports primary total hip replacement in Catalonia in the last 9 years, based on the Arthroplasty Registry of Catalonia (RACat). A review of the literature was carried out of the prosthesis (acetabular cups/stems) reported in the RACat between the period 2005 to 2013 in the following databases: ODEP (Orthopaedic Data Evaluation Panel), TRIP database, PubMed, and Google Scholar. Those prostheses implanted in less than 10 units (182 acetabular components corresponding to 49 models/228 stems corresponding to 63 models) were excluded. A total of 18,634 (99%) implanted acetabular cups were analysed out of a total number of 18,816, corresponding to 74 different models. In 18 models (2527 acetabular cups) no clinical evidence to support its use was found. An analysis was performed on 19,367 (98.84%) out of a total number of 19,595 implanted stems, corresponding to 75 different models. In 16 models (1845 stems) no clinical evidence was found to support their use. Variable evidence was found in the 56 models of acetabular cups (16,107) and 59 models of stems (17,522), most of it corresponding to level iv clinical evidence. There was a significant number implanted prostheses evaluated (13.56% acetabular cups/9.5% stems) for which no clinical evidence was found. The elevated number of models is highlighted (49 types for acetabular cups/63 types for stems) with less than 10 units implanted, which corresponds to only 1% of the total implants. The use of arthroplasty registers is shown to be an extremely helpful tool that allows analyses and conclusions to be made for the follow-up and post-marketing surveillance period. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Long-term role of external breast prostheses after total mastectomy.

PubMed

Glaus, Simone W; Carlson, Grant W

2009-01-01

After total mastectomy, many women choose to wear external breast prosthesis rather than undergo breast reconstruction. The purpose of this study was to evaluate long-term satisfaction among external breast prosthesis wearers and the impact of satisfaction on prosthesis use. A questionnaire was designed to assess demographic information, prosthesis information provision, prosthesis use, and satisfaction with prosthesis. Fifty-nine women who had undergone total mastectomy without breast reconstruction completed the questionnaire. The majority of women (68%) were at least 5 years out from mastectomy. Approximately half (49%) of the women had received information about breast prostheses prior to mastectomy; 29% received information from the surgeon performing the operation. Frequent and prolonged prosthesis use was prevalent with 64% of participants reporting prosthesis use all the time, 6-7 days/week. Participants showed high rates (83%) of overall satisfaction. However, women who wore their prosthesis out in public only were less satisfied than more frequent wearers (50% versus 89%, chi(2) = 8.83, d.f. = 1, alpha = 0.05). Satisfaction increased over time, as women who were greater than 5 years out from mastectomy were more satisfied than women less that 5 years post-mastectomy (90% versus 67%, chi(2) = 4.43, d.f. = 1, alpha = 0.05). The vast majority of women are satisfied with their external breast prosthesis several years after mastectomy. Most women used their prosthesis all the time and overall satisfaction contributed to higher levels of prosthesis use. Given the long-term importance of external breast prostheses for women who have undergone mastectomy, a greater effort to inform patients about external breast prostheses prior to surgery is needed.

What is the evidence base to guide surgical treatment of infected hip prostheses? systematic review of longitudinal studies in unselected patients

PubMed Central

2012-01-01

Background Prosthetic joint infection is an uncommon but serious complication of hip replacement. There are two main surgical treatment options, with the choice largely based on the preference of the surgeon. Evidence is required regarding the comparative effectiveness of one-stage and two-stage revision to prevent reinfection after prosthetic joint infection. Methods We conducted a systematic review to identify randomised controlled trials, systematic reviews and longitudinal studies in unselected patients with infection treated exclusively by one- or two-stage methods or by any method. The Embase, MEDLINE and Cochrane databases were searched up to March 2011. Reference lists were checked, and citations of key articles were identified by using the ISI Web of Science portal. Classification of studies and data extraction were performed independently by two reviewers. The outcome measure studied was reinfection within 2 years. Data were combined to produce pooled random-effects estimates using the Freeman-Tukey arc-sine transformation. Results We identified 62 relevant studies comprising 4,197 patients. Regardless of treatment, the overall rate of reinfection after any treatment was 10.1% (95% CI = 8.2 to 12.0). In 11 studies comprising 1,225 patients with infected hip prostheses who underwent exclusively one-stage revision, the rate of reinfection was 8.6% (95% CI = 4.5 to 13.9). After two-stage revision exclusively in 28 studies comprising 1,188 patients, the rate of reinfection was 10.2% (95% CI = 7.7 to 12.9). Conclusion Evidence of the relative effectiveness of one- and two-stage revision in preventing reinfection of hip prostheses is largely based on interpretation of longitudinal studies. There is no suggestion in the published studies that one- or two stage methods have different reinfection outcomes. Randomised trials are needed to establish optimum management strategies. PMID:22340795

Do modern total knee replacements offer better value for money? A health economic analysis.

PubMed

Hamilton, David F; Clement, Nicholas D; Burnett, Richard; Patton, James T; Moran, Mathew; Howie, Colin R; Simpson, A H R W; Gaston, Paul

2013-11-01

Cost effectiveness is an increasingly important factor in today's healthcare environment, and selection of arthroplasty implant is not exempt from such concerns. Quality adjusted life years (QALYs) are the typical tool for this type of evaluation. Using this methodology, joint arthroplasty has been shown to be cost effective; however, studies directly comparing differing prostheses are lacking. Data was gathered in a single-centre prospective double-blind randomised controlled trial comparing the outcome of modern and traditional knee implants, using the Short Form 6 dimensional (SF-6D) score and quality adjusted life year (QALY) methodology. There was significant improvement in the SF-6D score for both groups at one year (p < 0.0001). The calculated overall life expectancy for the study cohort was 15.1 years, resulting in an overall QALY gain of 2.144 (95% CI 1.752-2.507). The modern implant group demonstrated a small improvement in SF-6D score compared to the traditional design at one year (0.141 versus 0.143, p = 0.94). This difference resulted in the modern implant costing £298 less per QALY at one year. This study demonstrates that modern implant technology does not influence the cost-effectiveness of TKA using the SF-6D and QALY methodology. This type of analysis however assesses health status, and is not sensitive to joint specific function. Evolutionary design changes in implant technology are thus unlikely to influence QALY analysis following joint replacement, which has important implications for implant procurement.

Operative tactics and results of treatment of patients with coxarthrosis secondary to congenital high luxation of hip joints.

PubMed

Król, Roman; Rojewski, Marek; Kamiński, Adam; Popławski, Tomasz

2007-01-01

Treatment of the sequelae of congenital high luxation of the hip joint is a major challenge in prosthetic surgery, demanding from the operator thorough familiarity with the problem and experience in hop reconstructive surgery. The results of 4 years observation, of the treatment of 14 woman in the average age of 38 years old with 18 hip joints with congenital high luxation are presented. In all cases cementless total hip arthroplasty was made. Acetabular component of the prosthesis was implanted correctly and stable in its physiological placement. Femur was shortened average 4 cm and stabilized by cementless press-fit stem of prosthesis. The place of femur osteotomy was covered with autogenic spongy bone from resected caput of femur. The union was achieved after average 10 weeks. In clinical assessment there were obtained 10 very good, 5 good and 3 satisfactory clinical results. There were no superficial or deep infections, no neurological disorders and no loosening of components of implanted prostheses observed. 1. Careful planning and carrying out the operative procedures allow to insert the acetabular component of the prosthesis in its physiological place and achieve good results. 2. Shortening of femur and repositioning of components of prosthesis in 90 degrees knee flexion and also position on broken bed after operative procedure allowed to avoid neurological disorders. 3. Cementless and hydroxyapatite-covered femoral component of the prosthesis correctly stabilize place of femur osteotomy.

Comparative study of design and PCL-substituting systems of total knee prosthesis.

PubMed

Adam, R; Orban, C; Orban, H

2014-01-01

The aim of this study is to assess postoperative results obtained by different knee implants. The main implant types differences are given by generally implant design and by PCL substituting systems that are used. Between 04.2004 - 02.2012 we have performed 506 total knee arthroplasties (TKA), on a group of 460 patients. Our choice, was for cemented total knee prostheses, using PCL-substituting systems. Regarding general design and PCL-substituting systems of the implant we had divided the main group in three lots. In order to assess post operative result we had used the American Knee Society Score(AKSS). All prostheses types that we had implanted, had registered satisfactory values of AKSS. Our study showed that one group scored higher values of AKSS, compared the other two, but there are not statistical semnificative differences (p=0,09). Celsius.

Prevalence of peri-implantitis in patients with implant-supported fixed prostheses.

PubMed

Schuldt Filho, Guenther; Dalago, Haline Renata; Oliveira de Souza, João Gustavo; Stanley, Kyle; Jovanovic, Sascha; Bianchini, Marco Aurélio

2014-01-01

The purpose of this study was to evaluate periimplantitis prevalence in patients using implant-supported fixed prostheses that did not have any routine maintenance care. A total of 161 implants (27 patients) were evaluated in patients using implant-supported fixed prostheses. Collected data included information related to patient general health and local factors such as characteristics of implants, time in function, type of loading, positioning, Modified Bleeding Index, bacterial plaque, bleeding on probing (BOP), marginal recession, probing depth (PD), keratinized mucosa, and radiographic bone loss (BL). Factors related to the prostheses were also evaluated. The exclusion criteria were patients that have had any follow-up visit for plaque control of the prosthesis and/or the implants. From a total of 161 implants, 116 (72%) presented without peri-implantitis (PD > 4 mm + BOP + BL > 2 mm) while 45 (28%) had some sign of the disease. Implants placed in the maxilla were 2.98 times more likely to develop the disease (P < .05). Moreover, patients aged ≤ 60 years old were 3.24 times more likely to develop peri-implantitis (P < .05). Another analysis with statistical relevance (P < .05) was that implants with less than 3 mm interimplant distance were three times more likely to have peri-implantitis. There was no statistical relevance considering other analyses. It can be concluded that patients aged ≤ 60 years have a greater chance of presenting periimplantitis, as well as for implants positioned in the maxilla and those placed with an interimplant distance < 3 mm.

Integration of the Residual Limb with Prostheses via Direct Skin-Bone-Peripheral Nerve Interface

DTIC Science & Technology

2017-10-01

discussion of stated goals not met. Description shall include pertinent data and graphs in sufficient detail to explain any significant results achieved...A succinct description of the methodology used shall be provided. As the project progresses to completion, the emphasis in reporting in this section...correlation for eq. 1 was r = 0.836. The detailed description of how the joint moments and EMG activities were obtained and processed has been

Performance of automated multiplex PCR using sonication fluid for diagnosis of periprosthetic joint infection: a prospective cohort.

PubMed

Renz, Nora; Feihl, Susanne; Cabric, Sabrina; Trampuz, Andrej

2017-12-01

Sonication of explanted prostheses improved the microbiological diagnosis of periprosthetic joint infections (PJI). We evaluated the performance of automated multiplex polymerase chain reaction (PCR) using sonication fluid for the microbiological diagnosis of PJI. In a prospective cohort using uniform definition criteria for PJI, explanted joint prostheses were investigated by sonication and the resulting sonication fluid was analyzed by culture and multiplex PCR. McNemar's Chi-squared test was used to compare the performance of diagnostic tests. Among 111 patients, PJI was diagnosed in 78 (70%) and aseptic failure in 33 (30%). For the diagnosis of PJI, the sensitivity and specificity of periprosthetic tissue culture was 51 and 100%, of sonication fluid culture 58 and 100%, and of sonication fluid PCR 51 and 94%, respectively. Among 70 microorganisms, periprosthetic tissue culture grew 52 (74%), sonication fluid culture grew 50 (71%) and sonication fluid PCR detected 37 pathogens (53%). If only organisms are considered, for which primers are included in the test panel, PCR detected 37 of 58 pathogens (64%). The sonication fluid PCR missed 19 pathogens (predominantly oral streptococci and anaerobes), whereas 7 additional microorganisms were detected only by PCR (including Cutibacterium spp. and coagulase-negative staphylococci). The performance of multiplex PCR using sonication fluid is comparable to culture of periprosthetic tissue or sonication fluid. The advantages of PCR are short processing time (< 5 h) and fully automated procedure. However, culture technique is still needed due to the low sensitivity and the need of comprehensive susceptibility testing. Modification of primers or inclusion of additional ones may improve the performance of PCR, especially of low-virulent organisms.

Tribology and wear of metal-on-metal hip prostheses: influence of cup angle and head position.

PubMed

Williams, Sophie; Leslie, Ian; Isaac, Graham; Jin, Zhongmin; Ingham, Eileen; Fisher, John

2008-08-01

Clinical studies have indicated that the angular position of the acetabular cup may influence wear in metal-on-metal total hip bearings. A high cup angle in comparison to the anatomical position may lead to the head being constrained by the superior lateral surface and rim of the cup, thus potentially changing the location of the contact zone between the head and the cup. The aim of this study was to test the hypothesis that both a steep cup angle and a lateralized position of the head can increase head contact on the superior rim of the cup, with the consequence of increased wear. Hip-joint simulator studies of metal-on-metal bearings were undertaken with cup angles of 45 degrees and 55 degrees . The femoral head was either aligned to the center of the cup or placed in a position of microlateralization. Wear was measured gravimetrically over 5 million cycles. A steep cup angle of 55 degrees showed significantly higher long-term steady-state wear than a standard cup angle of 45 degrees (p < 0.01). The difference was fivefold. Microlateralization of the head resulted in a fivefold increase in steady-state wear compared with a centralized head. The combination of a steep cup angle and a microlateralized head increased the steady-state wear rate by tenfold compared with a standard cup angle with a centralized head. These studies support the hypothesis that both an increased cup angle and a lateral head position increase wear in metal-on-metal hip prostheses.

Above-knee prosthesis design based on fatigue life using finite element method and design of experiment.

PubMed

Phanphet, Suwattanarwong; Dechjarern, Surangsee; Jomjanyong, Sermkiat

2017-05-01

The main objective of this work is to improve the standard of the existing design of knee prosthesis developed by Thailand's Prostheses Foundation of Her Royal Highness The Princess Mother. The experimental structural tests, based on the ISO 10328, of the existing design showed that a few components failed due to fatigue under normal cyclic loading below the required number of cycles. The finite element (FE) simulations of structural tests on the knee prosthesis were carried out. Fatigue life predictions of knee component materials were modeled based on the Morrow's approach. The fatigue life prediction based on the FE model result was validated with the corresponding structural test and the results agreed well. The new designs of the failed components were studied using the design of experimental approach and finite element analysis of the ISO 10328 structural test of knee prostheses under two separated loading cases. Under ultimate loading, knee prosthesis peak von Mises stress must be less than the yield strength of knee component's material and the total knee deflection must be lower than 2.5mm. The fatigue life prediction of all knee components must be higher than 3,000,000 cycles under normal cyclic loading. The design parameters are the thickness of joint bars, the diameter of lower connector and the thickness of absorber-stopper. The optimized knee prosthesis design meeting all the requirements was recommended. Experimental ISO 10328 structural test of the fabricated knee prosthesis based on the optimized design confirmed the finite element prediction. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Tribology of total hip arthroplasty prostheses

PubMed Central

Rieker, Claude B.

2016-01-01

Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis. A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient. Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations. All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient’s objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004. PMID:28461928

No Differences Identified in Transverse Plane Biomechanics Between Medial Pivot and Rotating Platform Total Knee Implant Designs.

PubMed

Papagiannis, Georgios I; Roumpelakis, Ilias M; Triantafyllou, Athanasios I; Makris, Ioannis N; Babis, George C

2016-08-01

Total knee arthroplasties (TKAs) using well-designed, fixed bearing prostheses, such as medial pivot (MP), have produced good long-term results. Rotating-platform, posterior-stabilized (RP-PS) mobile bearing implants were designed to decrease polyethylene wear. Sagittal and coronal plane TKA biomechanics are well examined and correlated to polyethylene wear. However, limited research findings describe this relationship in transverse plane. We assumed that although axial plane biomechanics might not be the most destructive parameters on polyethylene wear, it is important to clarify their role because both joint kinematics and kinetics in all 3 planes are important input parameters for TKA wear testing (International Organization for Standardization 14243-1 and 14343-3). Our hypothesis was that transverse plane overall range of motion (ROM) and/or peak moment show differences that reflect on wear advantages when compared RP-PS implants to MP designs. Two groups (MPs = 24 and RP-PSs = 22 subjects) were examined by using 3D gait analysis. The variables were total internal-external rotation (IER) ROM and peak IER moments. No statistically significant difference was demonstrated between the 2 groups in kinetics (P = .389) or kinematics (P = .275). In the present study, no wear advantages were found between 2 TKAs. Both designs showed identical kinetics at the transverse plane in level-ground walking. Kinematic analysis could not illustrate any statistically significant difference in terms of overall IER ROM. Nevertheless, kinematic gait pattern differences observed possibly reflect different patterns of joint surface motion or abnormal gait patterns. Thus, wear testing with various input waveforms combined with functional data analysis will be necessary to identify the actual effects of gait variability on polyethylene wear. Copyright © 2016 Elsevier Inc. All rights reserved.

Prognostic factors associated with mortality in patients with septic arthritis: a descriptive cohort study.

PubMed

Andreasen, R A; Andersen, N S; Just, S A; Christensen, R; Hansen, Imj

2017-01-01

To evaluate the 30-day mortality rate of septic arthritis (SA) in adults in Funen, central Denmark, and to explore whether, at the time of SA presentation, risk factors for the 30-day mortality rate could be revealed. Our secondary objective was to describe the microbiological aetiologies, systemic signs of inflammation, and co-morbidity. A descriptive study identifying patients with SA from central Denmark, during the period 2006-2013, by the use of joint fluid culture data retrieved from the electronic database at the Department of Clinical Microbiology, Odense University Hospital. Patients with a positive joint fluid culture were considered eligible and their medical records were examined. We identified 215 patients with SA, mean age 64.8 years. At presentation, mean C-reactive protein (CRP) was 204 mg/L, mean white blood cell count (WBC) 11.9 × 10 9 /L, and mean body temperature 37.6°C. A total of 101 patients (47%) had a prosthetic joint, 46 (21%) had an inflammatory joint disease, and 24 (11%) had diabetes mellitus (DM). Staphylococcus aureus was the most common pathogen (104 patients, 48.4%). The 30-day mortality rate was 9.3% and the significant risk factor for death was liver disease at time of presentation [odds ratio (OR) 40.40, 95% confidence interval (CI) 5.38-303]. The other factors tested such as age > 65 years, elevated temperature, rheumatoid arthritis (RA), prostheses, and diabetes mellitus (DM) did not reach statistical significance. In our sample of patients with SA, we found a 30-day mortality rate in almost one in 10 adults. Among possible explanations, our study indicates that liver disease is a clinically relevant risk factor.

10-year evaluation of the cementless low-contact- stress rotating-platform total knee arthroplasty.

PubMed

Efstathopoulos, Nikolaos; Mavrogenis, Andreas F; Lallos, Stergios; Nikolaou, Vassilios; Papagelopoulos, Panayiotis J; Savvidou, Olga D; Korres, Demetrios S

2009-01-01

We present the clinical and radiographic outcomes of the cementless low-contact-stress (LCS) rotating-platform total knee arthroplasty. Overall, 423 prostheses were implanted in 393 consecutive patients (30 patients had bilateral total knee replacement) for primary varus gonarthrosis (381 patients) and rheumatoid arthritis (12 patients). There were 81 men and 312 women with a mean age of 73 years (range, 58-85 years). Patella replacement was not performed in any case. Clinical and radiographic evaluation was performed using the Knee Society Score (KSS) and the Knee Society Assessment Form, respectively. The mean follow-up was 10 years (range, 5-15 years). Three patients were lost to follow-up. Survival of the prostheses was 98% at 10 years; three prostheses required revision for deep infection, bearing dislocation, and periprosthetic fracture. The mean KSS improved significantly, from 42 and 44 points preoperatively to 90 and 79 points, respectively, at the latest evaluation (P < 0.001); results were excellent in 278 cases, good in 106, fair in 27, and poor in nine. Radiolucent lines were observed in 80 cases; revision arthroplasty was not performed in any of these cases. Complications included deep infection in one patient, bearing dislocation in one, skin necrosis in four, and a supracondylar fracture in one. The cementless LCS rotating-platform total knee arthroplasty is associated with excellent mid- and long-term results for patients with osteoarthritis and rheumatoid arthritis of the knee.

Rapidly growing non-tuberculous mycobacteria infection of prosthetic knee joints: A report of two cases.

PubMed

Kim, Manyoung; Ha, Chul-Won; Jang, Jae Won; Park, Yong-Beom

2017-08-01

Non-tuberculous mycobacteria (NTM) cause prosthetic knee joint infections in rare cases. Infections with rapidly growing non-tuberculous mycobacteria (RGNTM) are difficult to treat due to their aggressive clinical behavior and resistance to antibiotics. Infections of a prosthetic knee joint by RGNTM have rarely been reported. A standard of treatment has not yet been established because of the rarity of the condition. In previous reports, diagnoses of RGNTM infections in prosthetic knee joints took a long time to reach because the condition was not suspected, due to its rarity. In addition, it is difficult to identify RGNTM in the lab because special identification tests are needed. In previous reports, after treatment for RGNTM prosthetic infections, knee prostheses could not be re-implanted in all cases but one, resulting in arthrodesis or resection arthroplasty; this was most likely due to the aggressiveness of these organisms. In the present report, two cases of prosthetic knee joint infection caused by RGNTM (Mycobacterium abscessus) are described that were successfully treated, and in which prosthetic joints were finally reimplanted in two-stage revision surgery. Copyright © 2017 Elsevier B.V. All rights reserved.

Context-Dependent Upper Limb Prosthesis Control for Natural and Robust Use.

PubMed

Amsuess, Sebastian; Vujaklija, Ivan; Goebel, Peter; Roche, Aidan D; Graimann, Bernhard; Aszmann, Oskar C; Farina, Dario

2016-07-01

Pattern recognition and regression methods applied to the surface EMG have been used for estimating the user intended motor tasks across multiple degrees of freedom (DOF), for prosthetic control. While these methods are effective in several conditions, they are still characterized by some shortcomings. In this study we propose a methodology that combines these two approaches for mutually alleviating their limitations. This resulted in a control method capable of context-dependent movement estimation that switched automatically between sequential (one DOF at a time) or simultaneous (multiple DOF) prosthesis control, based on an online estimation of signal dimensionality. The proposed method was evaluated in scenarios close to real-life situations, with the control of a physical prosthesis in applied tasks of varying difficulties. Test prostheses were individually manufactured for both able-bodied and transradial amputee subjects. With these prostheses, two amputees performed the Southampton Hand Assessment Procedure test with scores of 58 and 71 points. The five able-bodied individuals performed standardized tests, such as the box&block and clothes pin test, reducing the completion times by up to 30%, with respect to using a state-of-the-art pure sequential control algorithm. Apart from facilitating fast simultaneous movements, the proposed control scheme was also more intuitive to use, since human movements are predominated by simultaneous activations across joints. The proposed method thus represents a significant step towards intelligent, intuitive and natural control of upper limb prostheses.

Rehabilitation for bilateral amputation of fingers

USGS Publications Warehouse

Stapanian, Martin A.; Stapanian, Adrienne M.P.; Staley, Keith E.

2010-01-01

We describe reconstructive surgeries, therapy, prostheses, and adaptations for a patient who experienced bilateral amputation of all five fingers of both hands through the proximal phalanges in January 1992. The patient made considerable progress in the use of his hands in the 10 mo after amputation, including nearly a 120% increase in the active range of flexion of metacarpophalangeal joints. In late 1992 and early 1993, the patient had "on-top plasty" surgeries, in which the index finger remnants were transferred onto the thumb stumps, performed on both hands. The increased web space and functional pinch resulting from these procedures made many tasks much easier. The patient and occupational therapists set challenging goals at all times. Moreover, the patient was actively involved in the design and fabrication of all prostheses and adaptations or he developed them himself. Although he was discharged from occupational therapy in 1997, the patient continues to actively find new solutions for prehension and grip strength 18 yr after amputation.

Quadriceps muscle injury in trans-femoral amputees.

PubMed

Alsindi, Z; Datta, D

1998-12-01

Two male trans-femoral amputees using modular trans-femoral prostheses lost control and fell to the ground when their prosthetic knees gave way. The semi-automatic knee lock malfunctioned in the first case while the free knee stabilising mechanics gave way in the second case. This resulted in a high tensile force acting on the contralateral quadriceps muscle causing it to rupture. As there are a significant number of patients with both kinds of prostheses it is important to be aware of this possibility so that necessary actions can be taken to minimise its occurrence. Even with the currently available weight activated stance phase control, the prosthetic knee will give way if the knee is flexed more than 20 degrees on weight bearing. Good power and control of hip extensors on the amputation side is needed to control the prosthetic knee joint, especially in the early stage of the walking cycle, i.e., from heel strike to mid-stance. Quadriceps muscle injury in amputees, as far as the authors are aware, has not been reported previously.

An economic model to evaluate cost-effectiveness of computer assisted knee replacement surgery in Norway.

PubMed

Gøthesen, Øystein; Slover, James; Havelin, Leif; Askildsen, Jan Erik; Malchau, Henrik; Furnes, Ove

2013-07-06

The use of Computer Assisted Surgery (CAS) for knee replacements is intended to improve the alignment of knee prostheses in order to reduce the number of revision operations. Is the cost effectiveness of computer assisted surgery influenced by patient volume and age? By employing a Markov model, we analysed the cost effectiveness of computer assisted surgery versus conventional arthroplasty with respect to implant survival and operation volume in two theoretical Norwegian age cohorts. We obtained mortality and hospital cost data over a 20-year period from Norwegian registers. We presumed that the cost of an intervention would need to be below NOK 500,000 per QALY (Quality Adjusted Life Year) gained, to be considered cost effective. The added cost of computer assisted surgery, provided this has no impact on implant survival, is NOK 1037 and NOK 1414 respectively for 60 and 75-year-olds per quality-adjusted life year at a volume of 25 prostheses per year, and NOK 128 and NOK 175 respectively at a volume of 250 prostheses per year. Sensitivity analyses showed that the 10-year implant survival in cohort 1 needs to rise from 89.8% to 90.6% at 25 prostheses per year, and from 89.8 to 89.9% at 250 prostheses per year for computer assisted surgery to be considered cost effective. In cohort 2, the required improvement is a rise from 95.1% to 95.4% at 25 prostheses per year, and from 95.10% to 95.14% at 250 prostheses per year. The cost of using computer navigation for total knee replacements may be acceptable for 60-year-old as well as 75-year-old patients if the technique increases the implant survival rate just marginally, and the department has a high operation volume. A low volume department might not achieve cost-effectiveness unless computer navigation has a more significant impact on implant survival, thus may defer the investments until such data are available.

Comparison of mechanical energy profiles of passive and active below-knee prostheses: a case study.

PubMed

Takahashi, Kota Z; Horne, John R; Stanhope, Steven J

2015-04-01

With the recent technological advancements of prosthetic lower limbs, there is currently a great desire to objectively evaluate existing prostheses. Using a novel biomechanical analysis, the purpose of this case study was to compare the mechanical energy profiles of anatomical and two disparate prostheses: a passive prosthesis and an active prosthesis. An individual with a transtibial amputation who customarily wears a passive prosthesis (Elation, Össur) and an active prosthesis (BiOM, iWalk, Inc.) and 11 healthy subjects participated in an instrumented gait analysis. The total mechanical power and work of below-knee structures during stance were quantified using a unified deformable segment power analysis. Active prosthesis generated greater peak power and total positive work than passive prosthesis and healthy anatomical limbs. The case study will enhance future efforts to objectively evaluate prosthetic functions during gait in individuals with transtibial amputations. A prosthetic limb should closely replicate the mechanical energy profiles of anatomical limbs. The unified deformable (UD) analysis may be valuable to facilitate future clinical prescription and guide fine adjustments of prosthetic componentry to optimize gait outcomes. © The International Society for Prosthetics and Orthotics 2014.

Artificial organs versus regenerative medicine: is it true?

PubMed

Nosé, Yukihiko; Okubo, Hisashi

2003-09-01

Individuals engaged in the fields of artificial kidney and artificial heart have often mistakenly stated that "the era of artificial organs is over; regenerative medicine is the future." Contrarily, we do not believe artificial organs and regenerative medicine are different medical technologies. As a matter of fact, artificial organs developed during the last 50 years have been used as a bridge to regeneration. The only difference between regenerative medicine and artificial organs is that artificial organs for the bridge to regeneration promote tissue regeneration in situ, instead of outside the body (for example, vascular prostheses, neuroprostheses, bladder substitutes, skin prostheses, bone prostheses, cartilage prostheses, ligament prostheses, etc.). All of these artificial organs are successful because tissue regeneration over a man-made prosthesis is established inside the patient's body (artificial organs to support regeneration). Another usage of the group of artificial organs for the bridge to regeneration is to sustain the functions of the patient's diseased organs during the regeneration process of the body's healthy tissues and/or organs. This particular group includes artificial kidney, hepatic assist, respiratory assist, and circulatory assist. Proof of regeneration of these healthy tissues and/or organs is demonstrated in the short-term recovery of end-stage organ failure patients (artificial organs for bridge to regeneration). A third group of artificial organs for the bridge to regeneration accelerates the regenerating process of the patient's healthy tissues and organs. This group includes neurostimulators, artificial blood (red cells) blood oxygenators, and plasmapheresis devices, including hemodiafiltrators. So-called "therapeutic artificial organs" fall into this category (artificial organs to accelerate regeneration). Thus, almost all of today's artificial organs are useful in the bridge to regeneration of healthy natural tissues and organs. It does not matter whether these tissues are cultivated inside or outside the patient's body. Thus, we strongly believe in the need for joint development programs between artificial organ technologies and regenerative medicine technologies. In particular, the importance of using both man-made substitute organ technologies and natural tissue-derived substitute organ technologies is stressed for improved medical care in the future.

Usefulness of Mitral Valve Prosthetic or Bioprosthetic Time Velocity Index Ratio to Detect Prosthetic or Bioprosthetic Mitral Valve Dysfunction.

PubMed

Luis, Sushil Allen; Blauwet, Lori A; Samardhi, Himabindu; West, Cathy; Mehta, Ramila A; Luis, Chris R; Scalia, Gregory M; Miller, Fletcher A; Burstow, Darryl J

2017-10-15

This study aimed to investigate the utility of transthoracic echocardiographic (TTE) Doppler-derived parameters in detection of mitral prosthetic dysfunction and to define optimal cut-off values for identification of such dysfunction by valve type. In total, 971 TTE studies (647 mechanical prostheses; 324 bioprostheses) were compared with transesophageal echocardiography for evaluation of mitral prosthesis function. Among all prostheses, mitral valve prosthesis (MVP) ratio (ratio of time velocity integral of MVP to that of left ventricular outflow tract; odds ratio [OR] 10.34, 95% confidence interval [95% CI] 6.43 to 16.61, p<0.001), E velocity (OR 3.23, 95% CI 1.61 to 6.47, p<0.001), and mean gradient (OR 1.13, 95% CI 1.02 to 1.25, p=0.02) provided good discrimination of clinically normal and clinically abnormal prostheses. Optimal cut-off values by receiver operating characteristic analysis for differentiating clinically normal and abnormal prostheses varied by prosthesis type. Combining MVP ratio and E velocity improved specificity (92%) and positive predictive value (65%) compared with either parameter alone, with minimal decline in negative predictive value (92%). Pressure halftime (OR 0.99, 95% CI 0.98 to 1.00, p=0.04) did not differentiate between clinically normal and clinically abnormal prostheses but was useful in discriminating obstructed from normal and regurgitant prostheses. In conclusion, cut-off values for TTE-derived Doppler parameters of MVP function were specific to prosthesis type and carried high sensitivity and specificity for identifying prosthetic valve dysfunction. MVP ratio was the best predictor of prosthetic dysfunction and, combined with E velocity, provided a useful parameter for determining likelihood of dysfunction and need for further assessment. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Improvement on upper limb body-powered prostheses (1921-2016): A systematic review.

PubMed

Hashim, Nur Afiqah; Abd Razak, Nasrul Anuar; Abu Osman, Noor Azuan; Gholizadeh, Hossein

2018-01-01

Body-powered prostheses are known for their advantages of cost, reliability, training period, maintenance, and proprioceptive feedback. This study primarily aims to analyze the work related to the improvement of upper limb body-powered prostheses prior to 2016. A systematic review conducted via the search of the Web of Science electronic database, Google Scholar, and Google Patents identified 155 papers from 1921 to 2016. Sackett's initial rules of evidence were used to determine the levels of evidence, and only papers categorized in the design and development category and patents were analyzed. A total of 40 papers in the sixth level of "Design and Development" of an upper limb body-powered prosthesis were found. Approximately 81% were categorized under mechanical alteration. Most papers were patent-type documents (48%), with the Journal of Rehabilitation Research and Development publishing most of the articles related to the design and development of body-powered prostheses. Papers in the scope of the study were published once every 3 years in almost a century, proving that only a few studies were conducted to improve body-powered arms compared with myoelectric technology. Further research should be carried out mainly in areas that have received less attention.

Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain.

PubMed

Terrier, Alexandre; Fernandes, Caroline Sieger; Guillemin, Maïka; Crevoisier, Xavier

2017-10-01

Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure. With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position. Both prostheses were obtained from the same manufacturer. They were tested on seven tibias with maximum axial compression force during walking. We tested the hypothesis that there was a difference of bone strain, bone-implant interfacial stress, and bone support between the three cases. We also evaluated, for the three cases, the correlations between bone support, bone strain and bone-implant interfacial stress. There were no statistically significant differences between the three cases. Overall, bone support was mainly trabecular, and less effective in the posterior side. Bone strain and bone-implant interfacial stress were strongly correlated to bone support. Even if slight differences are observed between fixed and mobile bearing, it is not enough to put forward the superiority of one of these implants regarding their reaction to axial compression. When associated to the published clinical results, our study provides no argument to warn surgeons against the use of two-components fixed bearing implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tribology of total hip arthroplasty prostheses: What an orthopaedic surgeon should know.

PubMed

Rieker, Claude B

2016-02-01

Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis.A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient.Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations.All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient's objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004.

The utility of international shoulder joint replacement registries and databases: a comparative analytic review of two hundred and sixty one thousand, four hundred and eighty four cases.

PubMed

Bayona, Carlos Eduardo Afanador; Somerson, Jeremy S; Matsen, Frederick A

2018-02-01

National registries are valuable tools for understanding the results of shoulder arthroplasty across populations. These databases provide an unselected view of shoulder joint replacement within geographical areas that cannot be obtained from case series or prospective studies. They can be particularly helpful in determining which diagnoses, patients, procedures, and prostheses have higher than expected rates of revision. In an attempt to determine the generalizability of registry data, we asked, 'how similar are the patients and procedures among the different national registries?' We analyzed national shoulder arthroplasty registries and databases accessed via Internet portals and through a PubMed literature search. Seven national/regional registries and five publications regarding national shoulder arthroplasty data were identified; these sources contained a combined total of 261,484 shoulder arthroplasty cases. The percentages of hemiarthroplasty, anatomic (aTSA) and reverse total shoulders (rTSA), the diagnoses leading to arthroplasty, the mean patient age, and the distribution of patient gender varied significantly among these different databases. This study indicates that the indications for and application of shoulder arthroplasty have important geographical variations and that these variations must be considered when comparing outcomes of shoulder arthroplasty from different locations. Without controlling for age, gender, diagnosis and procedure type, the results from one national registry may not be applicable to patients from a different location. In that national data provide the opportunity to reduce costs by identifying implants and procedures with higher failure rates, the funding of registries needs to be free of conflicts of interest.

Dual-energy CT and ceramic or titanium prostheses material reduce CT artifacts and provide superior image quality of total knee arthroplasty.

PubMed

Kasparek, Maximilian F; Töpker, Michael; Lazar, Mathias; Weber, Michael; Kasparek, Michael; Mang, Thomas; Apfaltrer, Paul; Kubista, Bernd; Windhager, Reinhard; Ringl, Helmut

2018-06-07

To evaluate the influence of different scan parameters for single-energy CT and dual-energy CT, as well as the impact of different material used in a TKA prosthesis on image quality and the extent of metal artifacts. Eight pairs of TKA prostheses from different vendors were examined in a phantom set-up. Each pair consisted of a conventional CoCr prosthesis and the corresponding anti-allergic prosthesis (full titanium, ceramic, or ceramic-coated) from the same vendor. Nine different (seven dual-energy CT and two single-energy CT) scan protocols with different characteristics were used to determine the most suitable CT protocol for TKA imaging. Quantitative image analysis included assessment of blooming artifacts (metal implants appear thicker on CT than they are, given as virtual growth in mm in this paper) and streak artifacts (thick dark lines around metal). Qualitative image analysis was used to investigate the bone-prosthesis interface. The full titanium prosthesis and full ceramic knee showed significantly fewer blooming artifacts compared to the standard CoCr prosthesis (mean virtual growth 0.6-2.2 mm compared to 2.9-4.6 mm, p < 0.001). Dual-energy CT protocols showed less blooming (range 3.3-3.8 mm) compared to single-energy protocols (4.6-5.5 mm). The full titanium and full ceramic prostheses showed significantly fewer streak artifacts (mean standard deviation 77-86 Hounsfield unit (HU)) compared to the standard CoCr prosthesis (277-334 HU, p < 0.001). All dual-energy CT protocols had fewer metal streak artifacts (215-296 HU compared to single-energy CT protocols (392-497 HU)). Full titanium and ceramic prostheses were ranked superior with regard to the image quality at the bone/prosthesis interface compared to a standard CoCr prosthesis, and all dual-energy CT protocols were ranked better than single-energy protocols. Dual-energy CT and ceramic or titanium prostheses reduce CT artifacts and provide superior image quality of total knee arthroplasty at the bone/prosthesis interface. These findings support the use of dual-energy CT as a solid imaging base for clinical decision-making and the use of full-titanium or ceramic prostheses to allow for better CT visualization of the bone-prosthesis interface.

Management of a Complex, Multioperated Intra-Articular Distal Radius Fracture

PubMed Central

Giwa, Lolade; Spacey, Kate; Packer, Greg

2015-01-01

Background Intra-articular distal radius fractures can have many complications, including radiocarpal osteoarthritis and distal radioulnar joint (DRUJ) dysfunction leading to pain and restricted wrist function. Case Description We describe the case of a 38-year-old patient who sustained a left distal radius intra-articular fracture, which was treated with volar plating. She developed pain from the radiocarpal joint as a result of intra-articular malunion and was listed for total wrist fusion. On the day of surgery this was converted to a Darrach procedure for minor DRUJ symptoms. This resulted in pain from the DRUJ as a result of instability, in addition to persisting radiocarpal arthritis pain. Due to her subsequent poor wrist function, she presented to the authors and underwent DRUJ arthroplasty with a proximally placed Scheker prosthesis to deal with her DRUJ symptoms and, later, a KinematX radiocarpal hemiarthroplasty for her radiocarpal symptoms. She remains happy with her outcome at 36-month follow-up. Literature Review The complications of the Darrach procedure include painful radioulnar convergence and wrist instability. The Scheker prosthesis allows restoration of stability of the DRUJ with good outcomes and 100% 5-year survival in one series. Sparing the midcarpal joint, the KinematX hemiarthroplasty allows preservation of the dart thrower's motion arc, which is key in many complex wrist movements and functions. Clinical Relevance This case highlights the negative consequences of distal ulna resection and shows both the Scheker and KinematX prostheses as viable, effective means to restore function to young, active patients with posttraumatic radiocarpal arthritis and/or instability. PMID:26261743

Pre-load on oral implants after screw tightening fixed full prostheses: an in vivo study.

PubMed

Duyck, J; Van Oosterwyck, H; Vander Sloten, J; De Cooman, M; Puers, R; Naert, I

2001-03-01

The fit of implant supported fixed prostheses is said to be of clinical concern because of the rigid fixation of an oral implant in its surrounding bone. The influence of the torque sequence of the set screws during fixation of implant supported fixed full prostheses on the final pre-load was investigated in vitro. No significant effect of the torque sequence of the set screws on the final pre-load was observed. The main objective of this study was to quantify and qualify the pre-load in vivo on implants supporting a fixed full prosthesis. This was performed when the prostheses were supported by all five or six implants and was repeated when the prostheses were supported by only four and three implants. A total of 13 patients with a fixed full implant supported prosthesis were selected. The existing abutments were changed for strain gauged abutments. After tightening the set screws with a torque of 10 N cm, the pre-load conditions were registered. The average (SEM) axial forces and bending moments in case of five or six, four and three supporting implants were 323 N (43 N), 346 N (59 N), 307 N (60 N) 21 N cm (3 N cm) and 21 N cm (2 N cm), 23 N cm (5 N cm), respectively. In addition, the pre-load was registered after fixation of a machined gold cylinder, as delivered by the manufacturer, on each of the supporting implants, representing the 'optimal fit' situation. The corresponding average (SEM) axial forces and bending moments in case of five or six, four and three supporting implants were 426 N (36 N), 405 N (40 N), 413 N (46 N) and 8 N cm (1 N cm), 8 N cm (1 N cm), 8 N cm (1 N cm), respectively. The induced axial forces after tightening the prostheses were significantly lower then after tightening the gold cylinder in case of five or six supporting implants (P < 0.02). The induced bending moments after tightening the prostheses were statistically significantly higher (P < 0.0001) then after tightening the gold cylinder in all test conditions (five or six, four or three supporting implants). This study underlines the static load present after screw tightening implant supported fixed full prostheses.

[Revision hip arthroplasty by Waldemar Link custom-made total hip prosthesis].

PubMed

Medenica, Ivica; Luković, Milan; Radoicić, Dragan

2010-02-01

The number of patients undergoing hip arthroplasty revision is constantly growing. Especially, complex problem is extensive loss of bone stock and pelvic discontinuity that requires reconstruction. The paper presented a 50-year old patient, who ten years ago underwent a total cement artrhroplasty of the left hip. A year after the primary operation the patient had difficulties in walking without crutches. Problems intensified in the last five years, the patient had severe pain, totally limited movement in the left hip and could not walk at all. Radiographically, we found loose femoral component, massive loss of bone stock of proximal femur, acetabular protrusion and a consequent pelvic discontinuity. Clinically, a completely disfunctional left hip joint was registered (Harris hip score--7.1). We performed total rearthroplasty by a custom-made Waldemar Link total hip prosthesis with acetabular antiprotrusio cage and compensation of bone defects with a graft from the bone bank. A year after the operation, we found clinically an extreme improvement in Harris hip score--87.8. Radiographically, we found stability of implanted components, a complete graft integration and bone bridging across the site of pelvic discontinuity. Pelvic discontinuity and massive loss of proximal femoral bone stock is a challenging and complex entity. Conventional prostheses cannot provide an adequate fixation and stability of the hip. Application of custom-made prosthesis (measured specificaly for a patient) and additional alografting bone defects is a good method in revision surgery after unsuccessful hip arthroplasty with extensive bone defects.

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints

PubMed Central

Sprecher, Christoph M; Wimmer, Markus A; Milz, Stefan; Taeger, Georg

2009-01-01

Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces. Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface. Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation. PMID:19421914

Economic Evaluation of the Combined Use of Warfarin and Low-dose Aspirin Versus Warfarin Alone in Mechanical Valve Prostheses.

PubMed

El-Hamamsy, Manal H; Elsisi, Gihan H; Eldessouki, Randa; Elmazar, Mohamed M; Taha, Ahmed S; Awad, Basma F; Elmansy, Hossam

2016-08-01

The use of combined therapy of antiplatelet and anticoagulant versus anticoagulant alone to reduce instances of thromboembolic events in patients with heart valve prostheses is an established standard of care in many countries but not in Egypt. A previous Markov model cost-effectiveness study on Egyptian patients aged 50-60 years demonstrated that the combined therapy reduces the overall treatment cost. However, due to the lack of actual real-world data on cost-effectiveness and the limitation of the Markov model study to 50- to 60-year-old patients, the Egyptian medical community is still questioning whether the added benefit is worth the cost. To assess, from the perspective of the Egyptian health sector, the cost-effectiveness of the combined use of warfarin and low-dose aspirin (75 mg) versus that of warfarin alone in patients with mechanical heart valve prostheses who began therapy between the age of 15 and 50 years. An economic evaluation was conducted alongside a randomized, controlled trial to assess the cost-effectiveness of the combined therapy in patients with mechanical valve prostheses. A total of 316 patients aged between 15 and 50 years were included in the study and randomly assigned to a group treated with both warfarin and aspirin or a group treated with warfarin alone. The patients in the combined therapy group exhibited a significantly longer duration of protection against the first event. Fewer primary events were observed in the patients treated with warfarin plus aspirin than in those treated with warfarin alone (1.4 %/year, vs. 4.8 %/year), and a higher mean quality-adjusted life-years (QALYs) value over 4 years was obtained for the group treated with warfarin plus aspirin (difference 0.058; 95 % CI 0.013-0.118), although this difference did not reach a conventional level of statistical significance. The total costs over a 4-year period were lower with the combined therapy (difference -US$244; 95 % CI -US$483.1 to -US$3.8), which yielded an incremental cost-effectiveness ratio of -US$4206 per QALY gained. Thus, the combined therapy was dominant. All costs were reported in US dollars (USD) for the financial year 2014. The results of this analysis indicate that from the perspective of the Egyptian health sector, the addition of aspirin to the typical warfarin therapy is more effective and less costly for patients with mechanical valve prostheses than treatment with warfarin alone. This combined strategy could be adopted to prevent the complications of mechanical valve prostheses. Our study adds to the body of evidence supporting the option of warfarin-plus-aspirin therapy for patients with mechanical valve prostheses.

Effect of light aging on silicone-resin bond strength in maxillofacial prostheses.

PubMed

Polyzois, Gregory; Pantopoulos, Antonis; Papadopoulos, Triantafillos; Hatamleh, Muhanad

2015-04-01

The aim of this study was to investigate the effect of accelerated light aging on bond strength of a silicone elastomer to three types of denture resin. A total of 60 single lap joint specimens were fabricated with auto-, heat-, and photopolymerized (n = 20) resins. An addition-type silicone elastomer (Episil-E) was bonded to resins treated with the same primer (A330-G). Thirty specimens served as controls and were tested after 24 hours, and the remaining were aged under accelerated exposure to daylight for 546 hours (irradiance 765 W/m(2) ). Lap shear joint tests were performed to evaluate bond strength at 50 mm/min crosshead speed. Two-way ANOVA and Tukey's test were carried out to detect statistical significance (p < 0.05). ANOVA showed that the main effect of light aging was the most important factor determining the shear bond strength. The mean bond strength values ranged from 0.096 to 0.136 MPa. The highest values were recorded for auto- (0.131 MPa) and photopolymerized (0.136 MPa) resins after aging. Accelerated light aging for 546 hours affects the bond strength of an addition-type silicone elastomer to three different denture resins. The bond strength significantly increased after aging for photo- and autopolymerized resins. All the bonds failed adhesively. © 2014 by the American College of Prosthodontists.

Impact of implant-supported prostheses on nutritional status and oral health perception in edentulous patients.

PubMed

El Osta, Nada; El Osta, Lana; Moukaddem, Farah; Papazian, Tatiana; Saad, Robert; Hennequin, Martine; Rabbaa Khabbaz, Lydia

2017-04-01

Improvement of nutritional status and perception of oral health are supposed to be different with complete conventional denture or implant-supported fixed or removable prostheses. Since no study has been conducted in Lebanon, the aim of our study was to assess the nutritional status and oral heath related quality of life (OHRQoL) in totally edentulous patients after treatment with complete denture or implant supported-prostheses. This was an observational clinical prospective study. A convenient sample of Lebanese people aged 60 years or more was selected between September 2013 and July 2015 from the Departments of removable and fixed prosthesis at Saint-Joseph University of Beirut. The treatment options included complete denture, implant-supported complete denture and implant-supported fixed prostheses. Nutritional status and OHRQoL were assessed with the Mini-Nutritional Assessment Index (MNA) and the Geriatric Oral Health Assessment Index (GOHAI) respectively at Baseline (first visit before treatment), 2-3 weeks after treatment (t1), 3 months (t2) and 6 months (t3) after treatment. Fifty-one participants (mean age: 69.39 ± 7.164 years) were included. The results have shown an improvement over time in nutritional status and OHRQoL for all treatment groups. However, 2-3 weeks after treatment the number of participants at risk of malnutrition was higher with complete removable denture, intermediate with implant-supported complete denture and lower with implant-supported fixed prostheses (p-value = 0.049). Moreover, the mean GOHAI score was significantly lower over time with complete removable denture compared to implant-supported prostheses (p-value <0.05). Our study has shown an enhancement in the quality of life and the nutritional status for implant supported-prostheses compared to conventional removable dentures. Therefore, it is fundamental that dentists communicate with their patients about implant treatment to understand their expectations, to explain the outcomes and achieve the desired clinical result. Copyright © 2017 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

High rate of osteolytic lesions in medium-term followup after the AES total ankle replacement.

PubMed

Kokkonen, Ari; Ikävalko, Mikko; Tiihonen, Raine; Kautiainen, Hannu; Belt, Eero A

2011-02-01

Some previous studies have shown a high percentage of early-onset and rapidly progressing osteolysis associated with total ankle arthroplasty (TAA) by the Ankle Evolutive System (AES). The purpose of our study was to analyze medium-term results at our institution. Altogether 38 TAAs using AES prostheses were carried out between 2003 and 2007. Diagnoses were rheumatoid arthritis (71%), post-traumatic and idiopathic osteoarthritis (29%). The mean age was 54 years, followup 28 months. Tibial and talar components had hydroxyapatite coating on metal (Co-Cr) components (HA-coated). Since 2005 the design was changed and components were porous coated with titanium and hydroxyapatite (dual-coated). Two-year survival was 79% (95% CI: 56 to 98). At followup 34 (89%) primary tibial and talar components were preserved. In 19 (50%) TAAs osteolysis (more than or equal to 2 mm) occurred in the periprosthetic bone area and in nine (24%) comprised large "cyst-like osteolysis''. In HA-coated prostheses radiolucent lines (less than or equal to 2 mm) or osteolysis (more than or equal to 2 mm) were detected in 11 (100%) cases and in dual-coated prostheses in 19 (74%) (p = 0.08). On the other hand there was more large "cyst-like osteolysis'' around the dual-coated prosthesis and lesions were larger (p = 0.017). In rheumatoid arthritis osteolysis was detected in 14 (52%) and large "cyst-like osteolysis'' in seven (26%) prostheses and in the group of traumatic and idiopathic osteoarthritis in six (55%) and two (18%), respectively. This study showed a high frequency of osteolysis in medium-term followup after the AES ankle replacement. The outcome was not sufficiently beneficial and we have discontinued use of this prosthesis.

Motor behavior during the first chewing cycle in subjects with fixed tooth- or implant-supported prostheses.

PubMed

Grigoriadis, Joannis; Trulsson, Mats; Svensson, Krister G

2016-04-01

Appropriate sensory information from periodontal mechanoreceptors (PMRs) is important for optimizing the positioning of food and adjustment of force vectors during precision biting. This study was designed to describe motor behavior during the first cycle of a natural chewing task and to evaluate the role of such sensory input in this behavior. While 10 subjects with natural dentition, 11 with bimaxillary fixed tooth-supported prostheses (TSP) and 10 with bimaxillary fixed implant-supported prostheses (ISP) (mean age 69 [range 61-83]) chewed a total of five hazelnuts, their vertical and lateral jaw movements were recorded. Data obtained during the first chewing cycle of each hazelnut were analyzed. The amplitude of vertical and lateral mandibular movement and duration of jaw opening did not differ between the groups, indicating similar behavior during this part of the chewing cycle. However, only 30% of the subjects in the natural dentate group, but 82% of those in the TSP and 70% in the ISP group exhibited slippage of the hazelnut during jaw closure in at least one of five trials. The TSP and ISP groups also exhibited more irregular and narrower patterns of motion (total lateral/vertical movement = 0.15 and 0.19, respectively, compared to 0.27 for the natural group). Subjects with fixed tooth- or implant-supported prostheses in both jaws show altered behavior, including inadequate control of the hazelnut, during the first chewing cycle. We propose that these differences are due to impairment or absence of sensory signaling from PMRs in these individuals. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An Investigation into a Gear-Based Knee Joint Designed for Lower Limb Prosthesis.

PubMed

Bhuiyan, M S H; Choudhury, I A; Dahari, M; Nukman, Y; Dawal, S Z

2017-01-01

A gear-based knee joint is designed to improve the performance of mechanical-type above-knee prostheses. The gear set with the help of some bracing, and bracket arrangement, is used to enable the prosthesis to follow the residual limb movement. The motion analysis and finite-element analysis (FEA) of knee joint components are carried out to assess the feasibility of the design. The maximum stress of 29.74 MPa and maximum strain of 2.393e-004 are obtained in the gear, whereas the maximum displacement of 7.975 mm occurred in the stopper of the knee arrangement. The factor of safety of 3.5 obtained from the FE analysis indicated no possibility of design failure. The results obtained from the FE analysis are then compared with the real data obtained from the literature for a similar subject. The pattern of motion analysis results has shown a great resemblance with the gait cycle of a healthy biological limb.

Identification of inducible nitric oxide synthase in human macrophages surrounding loosened hip prostheses.

PubMed Central

Watkins, S. C.; Macaulay, W.; Turner, D.; Kang, R.; Rubash, H. E.; Evans, C. H.

1997-01-01

Exposure of rodent macrophages to certain cytokines and endotoxin results in the synthesis of inducible nitric oxide synthase (iNOS or NOS-II) leading to the production of large amounts of nitric oxide (NO). Cultures of human macrophages, in contrast, do not produce iNOS after cytokine stimulation, and their ability to act as a physiological source of NO remains questionable. Here we have used immunohistochemistry and in situ hybridization to demonstrate the presence of iNOS within human macrophages present in the interfacial membrane and pseudocapsule that surround failed prosthetic hip joints. Synovial tissue recovered from normal human joints did not express iNOS. Many of the iNOS-positive macrophages within the interfacial membrane had phagocytosed large amounts of polyethylene wear debris, suggesting a role for phagocytic stimuli in inducing iNOS in human macrophages. These findings additionally support a role for NO in modulating the localized bone resorption that accompanies the aseptic loosening of prosthetic joints. Images Figure 1 Figure 2 Figure 3 PMID:9094976

An Investigation into a Gear-Based Knee Joint Designed for Lower Limb Prosthesis

PubMed Central

2017-01-01

A gear-based knee joint is designed to improve the performance of mechanical-type above-knee prostheses. The gear set with the help of some bracing, and bracket arrangement, is used to enable the prosthesis to follow the residual limb movement. The motion analysis and finite-element analysis (FEA) of knee joint components are carried out to assess the feasibility of the design. The maximum stress of 29.74 MPa and maximum strain of 2.393e−004 are obtained in the gear, whereas the maximum displacement of 7.975 mm occurred in the stopper of the knee arrangement. The factor of safety of 3.5 obtained from the FE analysis indicated no possibility of design failure. The results obtained from the FE analysis are then compared with the real data obtained from the literature for a similar subject. The pattern of motion analysis results has shown a great resemblance with the gait cycle of a healthy biological limb. PMID:28584518

The Effects of Fluid Absorption on the Mechanical Properties of Joint Prostheses Components

NASA Astrophysics Data System (ADS)

Yarbrough, David; Viano, Ann

2010-02-01

Ultra-high-molecular-weight polyethylene (UHMWPE) is the material playing the role of cartilage in human prosthetic joints. Wear debris from UHMWPE is a common reason for joint arthroplasty failure, and the exact mechanism responsible for wear remains an area of investigation. In this study, the microstructure of UHMWPE was examined as a function of fluid absorption. Samples with varying exposure to e-beam radiation (as part of the manufacturing process) were soaked for forty days in saline or artificial synovial fluid, under zero or 100 lbs load. Samples were then tensile-tested according to ASTM D-3895. The post-stressed material was then examined by transmission electron microscopy to evaluate the molecular response to stress, which correlates with macroscopic mechanical properties. Three parameters of the crystalline lamellae were measured: thickness, stacking ratio, and alignment to stress direction. Results indicate that fluid absorption does affect the mechanical properties of UHMWPE at both the microscopic and microscopic levels. )

Biofilm formation and design features of indwelling silicone rubber tracheoesophageal voice prostheses--an electron microscopical study.

PubMed

Leunisse, C; van Weissenbruch, R; Busscher, H J; van der Mei, H C; Dijk, F; Albers, F W

2001-01-01

After total laryngectomy, voice can be restored with a silicone rubber tracheoesophageal voice prosthesis. However, biofilm formation and subsequent deterioration of the silicone material of the prosthesis will limit device life by impairing valve function. To simulate the natural process of biofilm development under dynamic nutrient conditions, a modified Robbins device was used to evaluate the biofilm-related valve dysfunction of the Groningen, Provox2, Blom-Singer indwelling, and VoiceMaster voice prostheses. Obstruction of the semicircular slit-valved Groningen prosthesis leading to increased airway resistance was caused not only by a buildup of deposits on the esophageal flange and valve hat, but also by accumulation of deposits on the semicircular valve seating. The hinged flap valved Provox2 and indwelling Blom-Singer prostheses failed to close sufficiently because of biofilm formation on the valve seating. The esophageal flange of the VoiceMaster prosthesis was affected, but the tripod structure of the ball valve was fully colonized up to the titanium sleeve, which interfered with proper valve opening and closure. These findings on biofilm formation could be used for the further development and modification of critical design features of voice prostheses to facilitate tracheoesophageal speech. Copyright 2001 John Wiley & Sons, Inc.

In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.

PubMed

Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

2013-03-01

Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions. Copyright © 2012 Orthopaedic Research Society.

Prolonged incubation time does not increase sensitivity for the diagnosis of implant-related infection using samples prepared by sonication of the implants.

PubMed

Esteban, J; Alvarez-Alvarez, B; Blanco, A; Fernández-Roblas, R; Gadea, I; Garcia-Cañete, J; Sandoval, E; Valdazo, M

2013-07-01

We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

Oral rehabilitation of patients after maxillectomy. A systematic review.

PubMed

Dos Santos, D M; de Caxias, F P; Bitencourt, S B; Turcio, K H; Pesqueira, A A; Goiato, M C

2018-05-01

Patients who have maxillectomy can be rehabilitated with reconstructive surgery or obturator prostheses with or without osseointegratable implants. To identify studies on possible treatments in this group, we systematically searched the Scopus, Embase, PubMed/Medline, and Cochrane databases to collect data on patients' characteristics, radiotherapy, and results related to speech, swallowing, mastication or diet, chewing, aesthetics, and quality of life. Of the 1376 papers found, six were included, and one other was included after an additional search of references. A total of 252 patients were included, and of them, 86 had reconstructive surgery, 91 were treated with obturator prostheses, 39 had reconstructive surgery or obturator prostheses associated with implants, and 36 had reconstruction plus an obturator prosthesis. Data on radiotherapy were incomplete. There is a lack of consensus about the indication for rehabilitation, as the treatment must be based on the individual characteristics of each patient. Copyright © 2018 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Oral health-related quality of life and masticatory function after conventional prosthetic treatment: A cohort follow-up study.

PubMed

Palomares, Teresa; Montero, Javier; Rosel, Eva M; Del-Castillo, Ramón; Rosales, Juan I

2018-05-01

The impact of conventional prosthetic treatment on both the objective and subjective assessments of mastication as well as on well-being is unclear. The purpose of this clinical study was to compare the impact on oral health-related quality of life and masticatory function in participants treated with conventional dental prostheses. A total of 72 patients requiring prosthetic rehabilitation were enrolled by referral from the Faculty of Dentistry at the University of Granada, Spain. At baseline, demographic, behavioral, and clinical (prosthetic status, occlusal units) data were collected. In addition, the scores for quality of life, oral satisfaction, masticatory ability (Leake index), and masticatory performance (after 5, 10, and 15 cycles of bicolored chewing gum) were obtained. These records were obtained again at 6 to 8 weeks after insertion of the prostheses. The findings revealed that patients treated with fixed prostheses had better quality of life and better masticatory function than patients treated with removable prostheses. This result was even more pronounced for those treated with complete dentures. For all items, most of the treated patients improved the quality of life (average, 8.6 of the 4 items), although only between 5% and 15% of patients, especially those with a removable prosthesis, commented on functional impact after receiving treatment. Generally, masticatory performance was improved between 7% and 18% and was highly correlated not only with the number of natural teeth (r=0.61) and occlusal units (r=0.51) but also with subjective variables such as mastication satisfaction (r=0.31), impact on quality of life (r=0.30), or masticatory ability (r=0.30). Treatment with fixed prostheses achieved better results regarding quality of life, oral satisfaction, and masticatory function than treatment with removable prostheses. A moderate but significant correlation exists between the objective and subjective assessments of the masticatory functions. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

[Rehabilitation by hollow obturator prosthesis immediately after total maxillectomy for malignant tumor].

PubMed

Li, Xiao-ye; Yan, Ai-hui; Hao, Shuai; Li, Wei; Jiang, Xue-jun; Lu, Li; Qin, Xing-jun; Yan, Hai-xin

2011-05-01

The feasibility and clinical effects of hollow obturator prosthesis for the repair of maxillofacial defect immediately after maxillectomy for cancer were assessed. Thirteen patients with T3-4aN0M0 maxillary neoplasm were treated by the prostheses immediately after maxillectomy. According to the 3D-CT reconstruction of nasal sinus, the 3D stereoscopic prototype was constructed before the surgery. Simulating surgery with Surgicare 5.0 software and then the prosthesis 3D stereoscopic model was shaped. The prosthesis was made quickly and precisely with methacrylate resins according to the model and the print mold before surgery, with supplementary tooth at the bottom of prosthesis. In the surgery, the prosthesis was installed instantly after maxillectomy. The patients were followed up at 1, 3 and 6 month after the surgery, respectively. The facial features and the pronunciation clarity were examined and the questionnaires were carried out in the patients, with comparation by paired t-test. The hollow obturator prosthesis would be replaced by permanent prosthesis made of methacrylate resins at 6 month after the surgery. The hollow obturator prostheses were installed accurately and maxillofacial defects were repaired immediately after maxillectomy in the 13 patients. Postoperative follow-up showed there were significant differences in eyeball sagging (t = 4.67, P < 0.05), mid-facial region collapse (t = 5.67, P < 0.05), and pronunciation clarity (t = 16.38, P < 0.05) between patients with and without prostheses. Questionnaires showed that all the patients were satisfied with the retention of prostheses, the improvement of appearance, the improvement of the symptom of water choking and speech definition. Six months after the surgery, the hollow obturator prostheses were replaced smoothly by permanent prostheses in 11 of the 13 patients. The precise and instant repair of maxillofacial defect by prosthesis after maxillectomy can improve survival quality of patient.

Differential bacterial load on components of total knee prosthesis in patients with prosthetic joint infection.

PubMed

Holinka, Johannes; Pilz, Magdalena; Hirschl, Alexander M; Graninger, Wolfgang; Windhager, Reinhard; Presterl, Elisabeth

2012-10-01

The purpose of our study was to evaluate and quantify the bacterial adherence on different components of total knee prosthesis with the sonication culture method. Explanted components of all patients with presumptive prosthetic or implant infection were treated by sonication separately in sterile containers to dislodge the adherent bacteria from the surfaces and cultured. The bacterial load of the different knee components (femur, tibia, PE-inlay and patella) was evaluated by counting of colony-forming units (CFU) dislodged from the components surfaces using the sonication culture method. Overall, 27 patients had positive sonication cultures of explanted total knee prostheses. Microorganisms were detected from 88 of 100 explanted components. Twenty femoral components were culture positive and 7 negative, 23 tibial components as well as 23 polyethylene (PE) platforms had positive microorganism detection from the surface. Staphylococcus epidermidis adhered to the highest number of components whereas Staphylococcus aureus yielded the highest load of CFU in the sonication cultures. Although not significant, PE-inlays and tibial components were most often affected. The highest CFU count was detected in polyethylene components. The sonication culture method is a reliable method to detect bacteria from the components. Additionally, the results demonstrate that bacterial adherence is not affecting a single component of knee prosthesis only. Thus, in septic revision surgery partial prosthetic exchange or exchange of single polyethylene components alone may be not sufficient.

[Navigated implantation of total knee endoprostheses--a comparative study with conventional instrumentation].

PubMed

Jenny, J Y; Boeri, C

2001-01-01

A navigation system should improve the quality of a total knee prosthesis implantation in comparison to the classical, surgeon-controlled operative technique. The authors have implanted 40 knee total prostheses with an optical infrared navigation system (Orthopilot AESCULAP, Tuttlingen--group A). The quality of implantation was studied on postoperative long leg AP and lateral X-rays, and compared to a control group of 40 computer-paired total knee prostheses o the same model (Search Prosthesis, AESCULAP, Tuttlingen) implanted with a classical, surgeon-controlled technique (group B). An optimal mechanical femorotibial angle (3 degrees valgus to 3 degrees varus) was obtained by 33 cases in group A and 31 cases in group B (p > 0.05). Better results were seen for the coronal and sagittal orientation of both tibial and femoral components in group A. Globally, 26 cases of the group A and 12 cases of the group B were implanted in an optimal manner for all studied criteria (p < 0.01). The used navigation system allows a significant improvement of the quality of implantation of a knee total prosthesis in comparison to a classical, surgeon-controlled instrumentation. Long-term outcome could be consequently improved.

Assessing the Relative Contributions of Active Ankle and Knee Assistance to the Walking Mechanics of Transfemoral Amputees Using a Powered Prosthesis

PubMed Central

Simon, Ann M.; Hargrove, Levi J.

2016-01-01

Powered knee-ankle prostheses are capable of providing net-positive mechanical energy to amputees. Yet, there are limitless ways to deliver this energy throughout the gait cycle. It remains largely unknown how different combinations of active knee and ankle assistance affect the walking mechanics of transfemoral amputees. This study assessed the relative contributions of stance phase knee swing initiation, increasing ankle stiffness and powered plantarflexion as three unilateral transfemoral amputees walked overground at their self-selected walking speed. Five combinations of knee and ankle conditions were evaluated regarding the kinematics and kinetics of the amputated and intact legs using repeated measures analyses of variance. We found eliminating active knee swing initiation or powered plantarflexion was linked to increased compensations of the ipsilateral hip joint during the subsequent swing phase. The elimination of knee swing initiation or powered plantarflexion also led to reduced braking ground reaction forces of the amputated and intact legs, and influenced both sagittal and frontal plane loading of the intact knee joint. Gradually increasing prosthetic ankle stiffness influenced the shape of the prosthetic ankle plantarflexion moment, more closely mirroring the intact ankle moment. Increasing ankle stiffness also corresponded to increased prosthetic ankle power generation (despite a similar maximum stiffness value across conditions) and increased braking ground reaction forces of the amputated leg. These findings further our understanding of how to deliver assistance with powered knee-ankle prostheses and the compensations that occur when specific aspects of assistance are added/removed. PMID:26807889

Estimation of distal arm joint angles from EMG and shoulder orientation for transhumeral prostheses.

PubMed

Akhtar, Aadeel; Aghasadeghi, Navid; Hargrove, Levi; Bretl, Timothy

2017-08-01

In this paper, we quantify the extent to which shoulder orientation, upper-arm electromyography (EMG), and forearm EMG are predictors of distal arm joint angles during reaching in eight subjects without disability as well as three subjects with a unilateral transhumeral amputation and targeted reinnervation. Prior studies have shown that shoulder orientation and upper-arm EMG, taken separately, are predictors of both elbow flexion/extension and forearm pronation/supination. We show that, for eight subjects without disability, shoulder orientation and upper-arm EMG together are a significantly better predictor of both elbow flexion/extension during unilateral (R 2 =0.72) and mirrored bilateral (R 2 =0.72) reaches and of forearm pronation/supination during unilateral (R 2 =0.77) and mirrored bilateral (R 2 =0.70) reaches. We also show that adding forearm EMG further improves the prediction of forearm pronation/supination during unilateral (R 2 =0.82) and mirrored bilateral (R 2 =0.75) reaches. In principle, these results provide the basis for choosing inputs for control of transhumeral prostheses, both by subjects with targeted motor reinnervation (when forearm EMG is available) and by subjects without target motor reinnervation (when forearm EMG is not available). In particular, we confirm that shoulder orientation and upper-arm EMG together best predict elbow flexion/extension (R 2 =0.72) for three subjects with unilateral transhumeral amputations and targeted motor reinnervation. However, shoulder orientation alone best predicts forearm pronation/supination (R 2 =0.88) for these subjects, a contradictory result that merits further study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biotribological behavior of Ag-ZrCxN1-x coatings against UHMWPE for joint prostheses devices.

PubMed

Calderon V, S; Sánchez-López, J C; Cavaleiro, A; Carvalho, S

2015-01-01

This study aims to evaluate the structural, mechanical and tribological properties of zirconium carbonitrides (ZrCxN1-x) coatings with embedded silver nanoparticles, produced with the intention of achieving a material with enhanced multi-functional properties, including mechanical strength, corrosion resistance, tribological performance and antibacterial behavior suitable for their use in joint prostheses. The coatings were deposited by direct current (DC) reactive magnetron sputtering onto 316 L stainless steel, changing the silver content from 0 to 20 at% by modifying the current density applied to the targets. Different nitrogen and acetylene gas fluxes were used as reactive gases. The coatings revealed different mixtures of crystalline ZrCxN1-x, silver nanoparticles and amorphous carbon phases. The hardness of the films was found to be mainly controlled by the ratio between the hard (ZrCxN1-x) and soft (Ag and amorphous carbon) phases in the films, fluctuating between 7.4 and 20.4 GPa. The coefficient of friction, measured against ultra-high molecular weight polyethylene (UHMWPE) in Hank's balanced salt solution with 10 gL(-1) albumin, is governed by the surface roughness and hardness. The UHMWPE wear rates were in the same order of magnitude (between 1.4 and 2.0 × 10(-6)mm(3)N(-1)m(-1)), justified by the effect of the protective layer of albumin formed during the tests. The small differences were due to the hydrophobic/hydrophilic character of the surface, as well as to the silver content. Copyright © 2014 Elsevier Ltd. All rights reserved.

Clinical Presentation, Risk Factors, and Outcomes of Hematogenous Prosthetic Joint Infection in Patients with Staphylococcus aureus Bacteremia.

PubMed

Tande, Aaron J; Palraj, Bharath Raj; Osmon, Douglas R; Berbari, Elie F; Baddour, Larry M; Lohse, Christine M; Steckelberg, James M; Wilson, Walter R; Sohail, M Rizwan

2016-02-01

Staphylococcus aureus bacteremia is a life-threatening condition that may lead to metastatic infection, including prosthetic joint infection. To assess clinical factors associated with hematogenous prosthetic joint infection, we retrospectively reviewed all patients with a joint arthroplasty in place at the time of a first episode of S. aureus bacteremia over a 5-year period at our institution. Patients with postsurgical prosthetic joint infection without hematogenous prosthetic joint infection were excluded. There were 85 patients (143 arthroplasties) with either no prosthetic joint infection (n = 50; 58.8%) or hematogenous prosthetic joint infection in at least one arthroplasty (n = 35; 41.2%). The odds of hematogenous prosthetic joint infection was significantly increased among patients with community-acquired S. aureus bacteremia (odds ratio [OR] 18.07; 95% confidence interval [CI] 2.64-infinity; P = .001), as compared with nosocomial S. aureus bacteremia, in which there were no patients with hematogenous prosthetic joint infection. After adjusting for S. aureus bacteremia classification, the presence of ≥3 joint arthroplasties in place was associated with a nearly ninefold increased odds of hematogenous prosthetic joint infection as compared with those with 1-2 joint arthroplasties in place (OR 8.55; 95% CI 1.44-95.71; P = .012). All but one joint with prosthetic joint infection demonstrated at least one clinical feature suggestive of infection. There were 4 additional S. aureus prosthetic joint infections diagnosed during a median of 3.4 years of follow-up post hospitalization for S. aureus bacteremia. Prosthetic joint infection is frequent in patients with existing arthroplasties and concomitant S. aureus bacteremia, particularly with community-acquired S. aureus bacteremia and multiple prostheses. In contrast, occult S. aureus prosthetic joint infection without clinical features suggestive of prosthetic joint infection at the time of S. aureus bacteremia is rare. Copyright © 2016 Elsevier Inc. All rights reserved.

Early Complications of Immediate Loading in Edentulous Full-Arch Restorations: A Retrospective Analysis of 88 Cases.

PubMed

Cercadillo-Ibarguren, Iñaki; Sánchez-Torres, Alba; Figueiredo, Rui; Valmaseda-Castellón, Eduard

To describe the clinical outcomes and complications related to provisional prostheses after full-arch implant-supported rehabilitation by means of an immediate loading protocol. This retrospective cohort study included patients who were consecutively treated with full-arch implant-supported restorations with a minimum of four implants (Replace Select Tapered TiUnite, Nobel Biocare AB) per arch and conical abutments (multi-unit, Nobel Biocare AB) by means of an immediate loading protocol. The surgical procedures were performed between May 2006 and June 2014 by a single oral surgeon. Demographic, surgical, and prosthetic variables were collected, and biologic and mechanical complications were registered. A total of 61 maxillae (57%) and 46 mandibles (43%) were treated in 88 patients (40 men and 48 women) with a mean age of 62.4 years. A total of 558 implants were placed, 295 in postextraction sockets. A total of 331 implants (59.3%) were placed in the maxilla and 227 (40.7%) in the mandible. Within a 9-month period, 18 prostheses (16.8%) fractured (15 maxillary and 3 mandibular); in nine of these patients the opposing dentition was a full-arch, implant-supported restoration, and in the remaining nine patients, it was natural dentition. Six (1.1%) maxillary and three (0.5%) mandibular implants failed. A high implant survival rate is expected in the short term following this immediate loading protocol. Fracture of the provisional prosthesis is a common finding, affecting 17% of patients, and is significantly more prevalent in patients with bruxism and in maxillary prostheses.

The Overall Survival, Complication-Free Survival, and Related Complications of Combined Tooth-Implant Fixed Partial Dentures: A Literature Review

PubMed Central

Borg, Peter; Puryer, James; McNally, Lisa; O’Sullivan, Dominic

2016-01-01

This paper reviews the literature regarding possible complications, complication-free survival, and overall survival of fixed dental prostheses that use both implants and natural teeth as abutments. The paper also provides clinical guidelines for treatment based on this literature review. An electronic search utilizing the MEDLINE, BIOSIS Citation Index, and Web of Science™ Core Collection databases was undertaken, and a review of the 25 selected texts studying 22 different patient cohorts was carried out. From a total of 1610 implants reviewed, 40 were lost (33 due to loss of integration and 7 due to fracture), whereas, out of a total of 1301 teeth, 38 were lost, of which 16 were due to fracture. Seventy-three cases of tooth intrusion were detected. From a total of 676 frameworks reviewed (metal n = 645, Zirconia n = 31), 7 fractured, while veneer material fracture occurred in 70 out of 672 bridges. Overall, 502 out of 531 tooth-implant fixed prostheses (TIPFs) remained functional, and 336 out of 439 prostheses showed no technical or biological complications and remained functional. Rigid TIFPs permanently cemented to teeth with sufficient coronal structure and with limited use of prosthetic attachments offer a good long-term treatment option to patients with good oral hygiene following sound implant placement. This mode of treatment should be used when free-standing implant-supported options may not be possible. Larger randomized control studies and other clinical studies comparing tooth-to-implant-connected treatment with other forms of treatment are needed to better understand the place of TIFP treatment in oral rehabilitation. PMID:29563458

Characterization and Accelerated Ageing of UHMWPE Used in Orthopedic Prosthesis by Peroxide

PubMed Central

Rocha, Magda; Mansur, Alexandra; Mansur, Herman

2009-01-01

Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important mechanical properties to extend the longevity of knee prostheses. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, its mechanism is not accurately understood yet. Thus, in the present study an accelerated ageing of UHMWPE in hydrogen peroxide solution was performed and relative oxidation was extensively characterized by Fourier Transformed Infrared Spectroscopy (FTIR) spectroscopy and the morphological changes were analyzed by Scanning Electron Microscopy (SEM). Different chemical groups of UHMWPE associated with the degradation reaction were monitored for over 120 days in order to evaluate the possible oxidation mechanism(s) which may have occurred. The results have provided strong evidence that the oxidation mechanism is rather complex, and two stages with their own particular first-order kinetics reaction patterns have been clearly identified. Furthermore, hydrogen peroxide has proven to be an efficient oxidative medium to accelerate ageing of UHMWPE.

Effect of metal surface topography on mechanical bonding at simulated total hip stem-cement interfaces.

PubMed

Chen, C Q; Scott, W; Barker, T M

1999-01-01

Bonding and loosening mechanisms between bone cement and joint prostheses have not been well identified. In this study, the effects of simulated hip stem surface topography on the interfacial shear strength were examined. Six different surface topographies were used. They were described by several surface characterization parameters that may directly relate to the interfacial bonding strength: average surface roughness R(a), root mean square slope R(Deltaq), correlation length beta, and fluid retention index R(ri). The shear strengths between Palacos E bone cement and stainless steel rods were measured using an Instron materials testing machine. We found that cement can "flow" into the surface microtopography and establish good contact with the metal surface. The results show that the interfacial strength increases monotonically with the increase of R(Deltaq) instead of with R(a). The relationship between interfacial strength and surface parameters shows that a metal stem with an isotropic surface texture, higher R(Deltaq), and greater R(ri) gives a higher interfacial strength. Copyright 1999 John Wiley & Sons, Inc.

Arthroplasty knee registry of Catalonia: What scientific evidence supports the implantation of our prosthesis?

PubMed

Samaniego Alonso, R; Gaviria Parada, E; Pons Cabrafiga, M; Espallargues Carreras, M; Martinez Cruz, O

2018-02-28

In our environment, it is increasingly necessary to perform an activity based on scientific evidence and the field of prosthetic surgery should be governed by the same principles. The national arthroplasty registries allow us to obtain a large amount of data in order to evaluate this technique. The aim of our study is to analyse the scientific evidence that supports the primary total knee arthroplasties implanted in Catalonian public hospitals, based on the Arthoplasty Registry of Catalonia (RACat) MATERIAL AND METHODS: A review of the literature was carried out on knee prostheses (cruciate retaining, posterior stabilized, constricted and rotational) recorded in RACat between the period 2005-2013 in the following databases: Orthopedic Data Evaluation Panel, PubMed, TripDatabase and Google Scholar. The prostheses implanted in fewer than 10 units (1,358 prostheses corresponding to 62 models) were excluded. 41,947 prostheses (96.86%) were analysed out of 43,305 implanted, corresponding to 74 different models. In 13 models (n = 4,715) (11.24%) no clinical evidence to support their use was found. In the remaining 36 models (n = 13,609) (32.45%), level iv studies were the most predominant evidence. There was a significant number of implanted prostheses (11.24%) for which no clinical evidence was found. The number of models should be noted, 36 out of 110, with fewer than 10 units implanted. The use of arthroplasty registries has proved an extremely useful tool that allows us to analyse and draw conclusions in order to improve the efficiency of this surgical technique. Copyright © 2018 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prostheses and quantitation of visceral microembolism in dogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewanjee, M.K.; Fuster, V.; Rao, S.A.

1983-05-01

A noninvasive technique has been developed in the dog model for imaging, with a gamma camera, the platelet deposition on Bjoerk-Shiley mitral valve prostheses early postoperatively. At 25 hours after implantation of the prosthesis and 24 hours after intravenous administration of 400 to 500 microCi of platelets labeled with indium-111, the platelet deposition in the sewing ring and perivalvular cardiac tissue can be clearly delineated in a scintiphotograph. An in vitro technique was also developed for quantitation of visceral microemboli in brain, lungs, kidneys, and other tissues. Biodistribution of the labeled platelets was quantitated, and the tissue/blood radioactivity ratio wasmore » determined in 22 dogs in four groups: unoperated normal dogs, sham-operated dogs, prosthesis-implanted dogs, and prosthesis-implanted dogs treated with dipyridamole before and aspirin and dipyridamole immediately after operation. Fifteen to 20% of total platelets were consumed as a consequence of the surgical procedure. On quantitation, we found that platelet deposition on the components of the prostheses was significantly reduced in prosthesis-implanted animals treated with dipyridamole and aspirin when compared with prosthesis-implanted, untreated dogs. All prosthesis-implanted animals considered together had a twofold to fourfold increase in tissue/blood radioactivity ratio in comparison with unoperated and sham-operated animals, an indication that the viscera work as filters and trap platelet microemboli that are presumably produced in the region of the mitral valve prostheses. In the dog model, indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of platelet deposition on mechanical mitral valve prostheses, in vitro evaluation of platelet microembolism in viscera, in vitro quantitation of surgical consumption of platelets, and evaluation of platelet-inhibitor drugs.« less

Influence of oral health condition on swallowing and oral intake level for patients affected by chronic stroke.

PubMed

Mituuti, Cláudia T; Bianco, Vinicius C; Bentim, Cláudia G; de Andrade, Eduardo C; Rubo, José H; Berretin-Felix, Giédre

2015-01-01

According to the literature, the occurrence of dysphagia is high in cases of stroke, and its severity can be enhanced by loss of teeth and the use of poorly fitting prostheses. To verify that the status of oral health influences the level of oral intake and the degree of swallowing dysfunction in elderly patients with stroke in chronic phase. Thirty elderly individuals affected by stroke in chronic phase participated. All subjects underwent assessment of their oral condition, with classification from the Functional Oral Intake Scale (FOIS) and nasoendoscopic swallowing assessment to classify the degree of dysphagia. The statistical analysis examined a heterogeneous group (HG, n=30) and two groups designated by the affected body part, right (RHG, n=8) and left (LHG, n=11), excluding totally dentate or edentulous individuals without rehabilitation with more than one episode of stroke. There was a negative correlation between the need for replacement prostheses and the FOIS scale for the HG (P=0.02) and RHG (P=0.01). Differences in FOIS between types of prostheses of the upper dental arch in the LHG (P=0.01) and lower dental arch in the RHG (P=0.04). A negative correlation was found between the number of teeth present and the degree of dysfunction in swallowing liquid in the LHG (P=0.05). There were differences in the performance in swallowing solids between individuals without prosthesis and those with partial prosthesis in the inferior dental arch (P=0.04) for the HG. The need for replacement prostheses, type of prostheses, and the number of teeth of elderly patients poststroke in chronic phase showed an association with the level of oral intake and the degree of oropharyngeal dysphagia.

An integrated CAD/CAM/robotic milling method for custom cementless femoral prostheses.

PubMed

Wen-ming, Xi; Ai-min, Wang; Qi, Wu; Chang-hua, Liu; Jian-fei, Zhu; Fang-fang, Xia

2015-09-01

Aseptic loosening is the primary cause of cementless femoral prosthesis failure and is related to the primary stability of the cementless femoral prosthesis in the femoral cavity. The primary stability affects both the osseointegration and the long-term stability of cementless femoral prostheses. A custom cementless femoral prosthesis can improve the fit and fill of the prosthesis in the femoral cavity and decrease the micromotion of the proximal prosthesis such that the primary stability of the custom prosthesis can be improved, and osseointegration of the proximal prosthesis is achieved. These results will help to achieve long-term stability in total hip arthroplasty (THA). In this paper, we introduce an integrated CAD/CAM/robotic method of milling custom cementless femoral prostheses. The 3D reconstruction model uses femoral CT images and 3D design software to design a CAD model of the custom prosthesis. After the transformation matrices between two units of the robotic system are calibrated, consistency between the CAM software and the robotic system can be achieved, and errors in the robotic milling can be limited. According to the CAD model of the custom prosthesis, the positions of the robotic tool points are produced by the CAM software of the CNC machine. The normal vector of the three adjacent robotic tool point positions determines the pose of the robotic tool point. In conclusion, the fit rate of custom pig femur stems in the femoral cavities was 90.84%. After custom femoral prostheses were inserted into the femoral cavities, the maximum gaps between the prostheses and the cavities measured less than 1 mm at the diaphysis and 1.3 mm at the metaphysis. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Toward Balance Recovery With Leg Prostheses Using Neuromuscular Model Control

PubMed Central

Geyer, Hartmut

2016-01-01

Objective Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion. Methods We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user. Results In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and effectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls. Conclusions The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. Significance This work provides a potential avenue for future development of control policies that help improve amputee balance recovery. PMID:26315935

Neuroprostheses to treat neurogenic bladder dysfunction: current status and future perspectives.

PubMed

Rijkhoff, Nico J M

2004-02-01

Neural prostheses are a technology that uses electrical activation of the nervous system to restore function to individuals with neurological or sensory impairment. This article provides an introduction to neural prostheses and lists the most successful neural prostheses (in terms of implanted devices). The article then focuses on neurogenic bladder dysfunction and describes two clinically available implantable neural prostheses for treatment of neurogenic bladder dysfunction. Special attention is given to the usage of these neural prostheses in children. Finally, three new developments that may lead to a new generation of implantable neural prostheses for bladder control are described. They may improve the neural prostheses currently available and expand further the population of patients who can benefit from a neural prosthesis.

Longitudinal research on the oral environment of elderly wearing fixed or removable prostheses.

PubMed

Tanaka, Junko; Tanaka, Masahiro; Kawazoe, Takayoshi

2009-04-01

The purpose of this study was to investigate oral environmental risk factors involved in caries incidence in the elderly. We investigated the relationship between the oral environment factors of the elderly with both fixed prostheses and removable prostheses at baseline and at follow-up and examined time-course changes of each oral environmental factor by prosthesis type. The subject group consisted 11 elderly patients with fixed prostheses and 11 who wore removable prostheses. We examined oral environmental factors by saliva tests. Five oral environmental factors were examined: the stimulated salivary flow rate, buffering capacity, and the counts of mutans streptococci (SM), lactobacilli (LB), and Candida (CA). We compared these factors for subjects with fixed prostheses and those wearing removable prostheses at baseline and at follow-up. Furthermore, 3-year changes in the factors of each oral environment were compared and evaluated. Significant differences were observed between the two groups in the salivary microbial counts of SM and LB at baseline and at follow-up. The LB counts increased in the Denture group during the 3-year period and significant differences were noted. We found that fixed prostheses are less cariogenic, and removable prostheses cause an increase in the cariogenic bacterial count. Regarding time-course changes by the type of prosthesis, the LB count tended to increase in the subjects with removable prostheses. The risk of caries due to a fixed prosthesis may be lower than that of removable prostheses.

[Increasing the safety of ceramic femoral heads for hip prostheses].

PubMed

Willmann, G; Pfaff, H G; Richter, H G

1995-12-01

Since 1974 Biolox ceramic femoral ball heads have been used successfully for artificial modular hip joints. The revision rate due to ball head fracture is lower than 0.02%. This is an extremely low value. In this article it is shown how the safety of a ceramic ball head can be improved using the procedures of HIPing, engraving by laser technique, and 100% proof testing. By applying these means the materials properties density, grain size, grain size distribution, and the strength of the ball head, i.e. the fracture load can be improved significantly.

Qualitative and quantitative evaluation of some vocal function parameters following fitting of a prosthesis.

PubMed

Cavalot, A L; Palonta, F; Preti, G; Nazionale, G; Ricci, E; Vione, N; Albera, R; Cortesina, G

2001-12-01

The insertion of a prosthesis and restoration with pectoralis major myocutaneous flaps for patients subjected to total pharyngolaryngectomy is a technique now universally accepted; however the literature on the subject is lacking. Our study considers 10 patients subjected to total pharyngolaryngectomy and restoration with pectoralis major myocutaneous flaps who were fitted with vocal function prostheses and a control group of 50 subjects treated with a total laryngectomy without pectoralis major myocutaneous flaps and who were fitted with vocal function prostheses. Specific qualitative and quantitative parameters were compared. The quantitative measurement of the levels of voice intensity and the evaluation of the harmonics-to-noise ratio were not statistically significant (p > 0.05) between the two study groups at either high- or low-volume speech. On the contrary, statistically significant differences were found (p < 0.05) for the basic frequency of both the low and the high volume voice. For the qualitative analysis seven parameters were established for evaluation by trained and untrained listeners: on the basis of these parameters the control group had statistically better voices.

A new method to routinely achieve passive fit of ceramometal prostheses over Brånemark osseointegrated implants: a two-year report.

PubMed

Aparicio, C

1994-10-01

To maintain osseointegration, it is essential that the prosthesis fit with total passivity because the absence of a periodontal ligament makes the implant unable to adapt its position to a nonpassive framework. The traditional system of building a metal framework by melting over mechanized pieces--called gold cylinders in the Brånemark system--has been modified so these pieces are joined to the metal framework by means of physicochemical bonding. This bond is achieved by treating the metallic surfaces with a Silicoater system and a composite resin cement that sets in the mouth using an improved cementing protocol. In this paper, the clinical viability of this new philosophy, shown over 2 years, is presented. A total of 64 prostheses (39 maxillary and 25 mandibular) supported by 214 abutments, with an average observation period of 9 months, were evaluated. The results show that it is possible to routinely obtain a ceramometal prosthesis with a totally passive circular fitting while maintaining the possibility of retrieval, thus making postceramic soldering unnecessary.

a Review of Retinal Prosthesis Approaches

NASA Astrophysics Data System (ADS)

Kien, Tran Trung; Maul, Tomas; Bargiela, Andrzej

Age-related macular degeneration and retinitis pigmentosa are two of the most common diseases that cause degeneration in the outer retina, which can lead to several visual impairments up to blindness. Vision restoration is an important goal for which several different research approaches are currently being pursued. We are concerned with restoration via retinal prosthetic devices. Prostheses can be implemented intraocularly and extraocularly, which leads to different categories of devices. Cortical Prostheses and Optic Nerve Prostheses are examples of extraocular solutions while Epiretinal Prostheses and Subretinal Prostheses are examples of intraocular solutions. Some of the prostheses that are successfully implanted and tested in animals as well as humans can restore basic visual functions but still have limitations. This paper will give an overview of the current state of art of Retinal Prostheses and compare the advantages and limitations of each type. The purpose of this review is thus to summarize the current technologies and approaches used in developing Retinal Prostheses and therefore to lay a foundation for future designs and research directions.

Measurement of installation deformation of the acetabulum during prosthetic replacement of a hip joint using digital image correlation

NASA Astrophysics Data System (ADS)

Lei, Dong; Bai, Pengxiang; Zhu, Feipeng

2018-01-01

Nowadays, acetabulum prosthesis replacement is widely used in clinical medicine. However, there is no efficient way to evaluate the implantation effect of the prosthesis. Based on a modern photomechanics technique called digital image correlation (DIC), the evaluation method of the installation effect of the acetabulum was established during a prosthetic replacement of a hip joint. The DIC method determines strain field by comparing the speckle images between the undeformed sample and the deformed counterpart. Three groups of experiments were carried out to verify the feasibility of the DIC method on the acetabulum installation deformation test. Experimental results indicate that the installation deformation of acetabulum generally includes elastic deformation (corresponding to the principal strain of about 1.2%) and plastic deformation. When the installation angle is ideal, the plastic deformation can be effectively reduced, which could prolong the service life of acetabulum prostheses.

Alloplastic temporomandibular joint replacement systems: a systematic review of their history.

PubMed

De Meurechy, N; Mommaerts, M Y

2018-06-01

This systematic review provides an overview of the historical evolution of the prosthetic temporomandibular joint and addresses the challenges and complications faced by engineers and surgeons, in an effort to shed light on why only a few systems remain available. A better understanding of the history of temporomandibular joint prostheses might also provide insights into the origin of the negative public opinion of the prosthesis, which is based on outdated information. A computerized search using the PubMed Central, ScienceDirect, Wiley Online, Ovid, and Cochrane Library databases was performed following the PRISMA guidelines. Out of 7122 articles identified, 41 met the inclusion criteria for this systematic review. Although several historical reviews have been published previously, none has covered such an extensive time period or has described all designs. Furthermore, besides providing a historical overview, this review discusses the rationale behind the evolution in design and biomaterials, which have largely contributed to the outcomes of the prosthetic systems. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Nano-material aspects of shock absorption in bone joints.

PubMed

Tributsch, H; Copf, F; Copf, P; Hindenlang, U; Niethard, F U; Schneider, R

2010-01-01

This theoretical study is based on a nano-technological evaluation of the effect of pressure on the composite bone fine structure. It turned out, that the well known macroscopic mechano-elastic performance of bones in combination with muscles and tendons is just one functional aspect which is critically supported by additional micro- and nano- shock damping technology aimed at minimising local bone material damage within the joints and supporting spongy bone material. The identified mechanisms comprise essentially three phenomena localised within the three-dimensional spongy structure with channels and so called perforated flexible tensulae membranes of different dimensions intersecting and linking them. Kinetic energy of a mechanical shock may be dissipated within the solid-liquid composite bone structure into heat via the generation of quasi-chaotic hydromechanic micro-turbulence. It may generate electro-kinetic energy in terms of electric currents and potentials. And the resulting specific structural and surface electrochemical changes may induce the compressible intra-osseal liquid to build up pressure dependent free chemical energy. Innovative bone joint prostheses will have to consider and to be adapted to the nano-material aspects of shock absorption in the operated bones.

Within-subject comparisons of implant-supported mandibular prostheses: psychometric evaluation.

PubMed

de Grandmont, P; Feine, J S; Taché, R; Boudrias, P; Donohue, W B; Tanguay, R; Lund, J P

1994-05-01

In a within-subject cross-over clinical trial, psychometric and functional measurements were taken while 15 completely edentulous subjects wore mandibular fixed prostheses and long-bar removable implant-supported prostheses. In this paper, the results of a psychometric assessment are presented. Eight subjects first received the fixed bridge and seven the removable type. After having worn a prosthesis for a minimum of two months, subjects responded to psychometric scales that measured their perceptions of various factors associated with prostheses. They also chewed test foods while masticatory activity was recorded. The prostheses were then changed and the procedures repeated. At the end of the study, patients were asked to choose the prosthesis that they wished to keep. Patients assigned significantly higher scores, on visual analogue scales, to both types of implant-supported prostheses than to their original conventional prostheses for all factors tested, including general satisfaction. However, no statistically significant differences between the two implant-supported prostheses were detected except for the difficulty of chewing carrot, apple, and sausage. For these foods, the fixed prostheses were rated higher. Subjects' responses to category scales were consistent with their responses to the visual analogue scales. These results suggest that, although patients find the fixed bridge to be significantly better for chewing harder foods, there is no difference in their general satisfaction with the two types of prostheses.

Ankle mechanics during sidestep cutting implicates need for 2-degrees of freedom powered ankle-foot prostheses.

PubMed

Ficanha, Evandro M; Rastgaar, Mohammad; Kaufman, Kenton R

2015-01-01

The ankle joint of currently available powered prostheses is capable of controlling one degree of freedom (DOF), focusing on improved mobility in the sagittal plane. To increase agility, the requirements of turning in prosthesis design need to be considered. Ankle kinematics and kinetics were studied during sidestep cutting and straight walking. There were no significant differences between the ankle sagittal plane mechanics when comparing sidestep cutting and straight walking; however, significant differences were observed in ankle frontal plane mechanics. During straight walking, the inversion-eversion (IE) angles were smaller than with sidestep cutting. The ankle that initiated the sidestep cutting showed progressively increasing inversion from 2 to 13 degrees while the following contralateral step showed progressively decreasing inversion from 8 to -4 degrees during normal walking speed. The changes in IE kinematics were the most significant during sidestep cutting compared with straight walking. The IE moments of the step that initiated the sidestep cutting were always in eversion, acting as a braking moment opposing the inverting motion. This suggests that an ankle-foot prosthesis with active DOFs in the sagittal and frontal planes will increase the agility of gait for patients with limb loss.

Biomechanics of the ankle-foot system during stair ambulation: implications for design of advanced ankle-foot prostheses.

PubMed

Sinitski, Emily H; Hansen, Andrew H; Wilken, Jason M

2012-02-02

Unilateral lower limb prosthesis users display temporal, kinematic, and kinetic asymmetries between limbs while ascending and descending stairs. These asymmetries are due, in part, to the inability of current prosthetic devices to effectively mimic normal ankle function. The purpose of this study was to provide a comprehensive set of biomechanical data for able-bodied and unilateral transtibial amputee (TTA) ankle-foot systems for level-ground (LG), stair ascent (SA), and stair descent (SD), and to characterize deviations from normal performance associated with prosthesis use. Ankle joint kinematics, kinetics, torque-angle curves, and effective shapes were calculated for twelve able-bodied individuals and twelve individuals with TTA. The data from this study demonstrated the prosthetic limb can more effectively mimic the range of motion and power output of a normal ankle-foot during LG compared to SA and SD. There were larger differences between the prosthetic and able-bodied limbs during SA and SD, most evident in the torque-angle curves and effective shapes. These data can be used by persons designing ankle-foot prostheses and provide comparative data for assessment of future ankle-foot prosthesis designs. Published by Elsevier Ltd.

Post-Cam Design and Contact Stress on Tibial Posts in Posterior-Stabilized Total Knee Prostheses: Comparison Between a Rounded and a Squared Design.

PubMed

Watanabe, Toshifumi; Koga, Hideyuki; Horie, Masafumi; Katagiri, Hiroki; Sekiya, Ichiro; Muneta, Takeshi

2017-12-01

The post-cam mechanism in posterior stabilized (PS) prostheses plays an important role in total knee arthroplasty (TKA). The purpose of this study is to clarify the difference of the contact stress on the tibial post between a rounded post-cam design and a squared design during deep knee flexion and at hyperextension using the three-dimensional (3D) finite element models. We created 2 types of 3D, finite element models of PS prostheses (types A and B), whose surfaces were identical except for the post-cam geometries: type A has a rounded post-cam design, while type B has a squared design. Both types have a similar curved-shape intercondylar notch of the femoral component. Stress distributions, peak contact stresses, and contact areas on the tibial posts at 90°, 120°, and 150° flexion with/without 10° tibial internal rotation and at 10° hyperextension were compared between the 2 models. Type B demonstrated more concentrated stress distribution compared to type A. The peak contact stresses were similar in both groups during neutral flexion; however, the stresses were much higher in type B during flexion with 10° rotation and at hyperextension. The higher peak contact stresses corresponded to the smaller contact areas in the tibial post. A rounded post-cam design demonstrated less stress concentration during flexion with rotation and at hyperextension compared with a squared design. The results would be useful for development of implant designs and prediction of the contact stress on the tibial post in PS total knee arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

The Effect on Long-Term Survivorship of Surgeon Preference for Posterior-Stabilized or Minimally Stabilized Total Knee Replacement: An Analysis of 63,416 Prostheses from the Australian Orthopaedic Association National Joint Replacement Registry.

PubMed

Vertullo, Christopher J; Lewis, Peter L; Lorimer, Michelle; Graves, Stephen E

2017-07-05

Controversy still exists as to the optimum management of the posterior cruciate ligament (PCL) in total knee arthroplasty. Surgeons can choose to kinematically substitute the PCL with a posterior-stabilized total knee replacement or alternatively to utilize a cruciate-retaining, also known as minimally stabilized, total knee replacement. Proponents of posterior-stabilized total knee replacement propose that the reported lower survivorship in registries when directly compared with minimally stabilized total knee replacement is due to confounders such as selection bias because of the preferential usage of posterior-stabilized total knee replacement in more complex or severe cases. In this study, we aimed to eliminate these possible confounders by performing an instrumental variable analysis based on surgeon preference to choose either posterior-stabilized or minimally stabilized total knee replacement, rather than the actual prosthesis received. Cumulative percent revision, hazard ratio (HR), and revision diagnosis data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry from September 1, 1999, to December 31, 2014, for 2 cohorts of patients, those treated by high-volume surgeons who preferred minimally stabilized replacements and those treated by high-volume surgeons who preferred posterior-stabilized replacements. All patients had a diagnosis of osteoarthritis and underwent fixed-bearing total knee replacement with patellar resurfacing. At 13 years, the cumulative percent revision was 5.0% (95% confidence interval [CI], 4.0% to 6.2%) for the surgeons who preferred the minimally stabilized replacements compared with 6.0% (95% CI, 4.2% to 8.5%) for the surgeons who preferred the posterior-stabilized replacements. The revision risk for the surgeons who preferred posterior-stabilized replacements was significantly higher for all causes (HR = 1.45 [95% CI, 1.30 to 1.63]; p < 0.001), for loosening or lysis (HR = 1.93 [95% CI, 1.58 to 2.37]; p < 0.001), and for infection (HR = 1.51 [95% CI, 1.25 to 1.82]; p < 0.001). This finding was irrespective of patient age and was evident with cemented fixation and with both cross-linked polyethylene and non-cross-linked polyethylene. However, the higher revision risk was only evident in male patients. There was a 45% higher risk of revision for the patients of surgeons who preferred a posterior-stabilized total knee replacement compared with the patients of surgeons who preferred a minimally stabilized total knee replacement. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Total knee replacement with natural rollback.

PubMed

Wachowski, Martin Michael; Walde, Tim Alexander; Balcarek, Peter; Schüttrumpf, Jan Philipp; Frosch, Stephan; Stauffenberg, Caspar; Frosch, Karl-Heinz; Fiedler, Christoph; Fanghänel, Jochen; Kubein-Meesenburg, Dietmar; Nägerl, Hans

2012-03-20

A novel class of total knee replacement (AEQUOS G1) is introduced which features a unique design of the articular surfaces. Based on the anatomy of the human knee and differing from all other prostheses, the lateral tibial "plateau" is convexly curved and the lateral femoral condyle is posteriorly shifted in relation to the medial femoral condyle. Under compressive forces the configuration of the articular surfaces of human knees constrains the relative motion of femur and tibia in flexion/extension. This constrained motion is equivalent to that of a four-bar linkage, the virtual 4 pivots of which are given by the centres of curvature of the articulating surfaces. The dimensions of the four-bar linkage were optimized to the effect that constrained motion of the total knee replacement (TKR) follows the flexional motion of the human knee in close approximation, particularly during gait. In pilot studies lateral X-ray pictures have demonstrated that AEQUOS G1 can feature the natural rollback in vivo. Rollback relieves the load of the patello-femoral joint and minimizes retropatellar pressure. This mechanism should reduce the prevalence of anterior knee pain. The articulating surfaces roll predominantly in the stance phase. Consequently sliding friction is replaced by the lesser rolling friction under load. Producing rollback should minimize material wear due to friction and maximize the lifetime of the prosthesis. To definitely confirm these theses one has to wait for the long term results. Copyright © 2011 Elsevier GmbH. All rights reserved.

Biomechanical evaluation of two types of short-stemmed hip prostheses compared to the trust plate prosthesis by three-dimensional measurement of micromotions.

PubMed

Fottner, Andreas; Schmid, Markus; Birkenmaier, Christof; Mazoochian, Farhad; Plitz, Wolfgang; Volkmar, Jansson

2009-06-01

Stemless and short-stemmed hip prostheses have been developed to preserve femoral bone stock. While all these prostheses claim a more or less physiological load transfer, clinical long-term results are only available for the stemless thrust plate prosthesis. In this study, the in vitro primary stability of the thrust plate prosthesis was compared to two types of short-stemmed prostheses. In addition to the well-established Mayo prosthesis, the modular Metha prosthesis was tested using cone adapters with 130 degrees and 140 degrees neck-shaft-angles. The prostheses were implanted in composite femurs and loaded dynamically (300-1700 N). Three-dimensional micromotions at the bone-prosthesis interface were measured. In addition, the three-dimensional deformations at the surface of the composite femur were measured to gain data on the strain distribution. For all tested prostheses, the micromotions did not exceed 150 microm, the critical value for osteointegration. The thrust plate prosthesis revealed similar motions as the short-stemmed prostheses. The short-stemmed prosthesis with the 130 degrees cone tended to have the highest micromotions of all tested short-stemmed prostheses. The thrust plate prosthesis revealed the lowest alteration of bone surface deformation after implantation. The comparably low micromotions of the thrust plate prosthesis and the short-stemmed prostheses should be conducive to osseous integration. The higher alteration of load transmission after implantation reveals a higher risk of stress shielding for the short-stemmed prostheses.

Tribological assessment of a flexible carbon-fibre-reinforced poly(ether-ether-ketone) acetabular cup articulating against an alumina femoral head.

PubMed

Scholes, S C; Inman, I A; Unsworth, A; Jones, E

2008-04-01

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.

[Time course of microbial colonization of different voice prostheses].

PubMed

Schuldt, T; Dommerich, S; Pau, H-W; Kramp, B

2010-10-01

For the vocal rehabilitation of laryngectomized patients, voice prostheses are actually one of the best known methods. Caused by the surface colonisation with bacteria and fungi the life time of the prostheses is limited to 3-4 months. In a time period of 127 months we analysed the surface colonisation of 118 voice prostheses. The mean life time of the prostheses was 156 days. In reference to the prosthesis model we also recorded different times of usage (ESKA-Herrmann 141, Provox 2 184 and Provox 1 204 days (p>0.05)). In the microbiological examination the dominating bacteria were S. aureus, Klebsiella sp. and Proteus sp. It was possible to cultivate all these bacteria on every type of prosthesis used in the study. In addition C. albicans, C. glabrata, C. krusei and C. tropicalis were the main fungi on the silicone surface. Thereby a more frequent colonisation with C. krusei on ESKA-Herrmann prostheses was measured, caused by the bigger contact area with saliva on this model (p=0.034). Because of the similar position and way of function, all types of voice prostheses are colonized by almost the same species of bacteria and fungi. But in dependency of the type an affinity of individual species to special prostheses exist. The knowledge of these individual affinities is necessary for the further development of voice prostheses. Furthermore the diversity of bacteria and fungi species showed a level of saturation on the surface. This is caused by the limited space on the silicone prostheses. © Georg Thieme Verlag KG Stuttgart · New York.

Mechanical characterization and comparison of energy storage and return prostheses.

PubMed

Rigney, Stacey M; Simmons, Anne; Kark, Lauren

2017-03-01

The suitability of finite element analysis (FEA) for standardizing the mechanical characterization of energy storage and return (ESAR) prostheses was investigated. A methodology consisting of both experimental and numerical analysis was proposed and trialed for the Vari-flex ® Modular TM , Flex-foot Cheetah and Cheetah Xtreme by Össur ® and a 1E90 Sprinter by Ottobock ® . Gait analysis was conducted to determine suitable orientation angles for non-destructive testing (NDT) of the ESAR prostheses followed by a quasi-static inverse FEA procedure within COMSOL Multiphysics ® , where the NDT conditions were replicated to determine the homogenized material properties of the prostheses. The prostheses' loading response under bodyweight for an 80kg person was then simulated, using both Eigenfrequency and time-dependent analysis. The apparent stiffness under bodyweight was determined to be 94.7, 48.6, 57.4 and 65.0Nmm -1 for the Vari-flex ® Modular TM , Flex-foot Cheetah, Cheetah Xtreme and 1E90 Sprinter, respectively. Both the energy stored and returned by the prostheses varied negatively with stiffness, yet the overall efficiency of the prostheses were similar, at 52.7, 52.0, 51.7 and 52.4% for the abovementioned prostheses. The proposed methodology allows the standardized assessment and comparison of ESAR prostheses without the confounding influences of subject-specific gait characteristics. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses.

PubMed

Wellenberg, R H H; Boomsma, M F; van Osch, J A C; Vlassenbroek, A; Milles, J; Edens, M A; Streekstra, G J; Slump, C H; Maas, M

2017-03-01

To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. In 70 and 74keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130keV images, only mild/moderate metal artefacts were significantly reduced compared to 70 and 74keV images. Deviations in CT numbers, noise, SNRs and CNRs due to metal artefacts were decreased with respectively 64%, 57%, 62% and 63% (p<0.001) compared to unaffected pellets. Optimal keVs, based on CNRs, for different unilateral and bilateral metal hip prostheses consisting of different metal alloys varied from 74 to 150keV. The Titanium alloy resulted in less severe artefacts and were reduced more effectively compared to the Cobalt alloy. Virtual monochromatic dual-layer Spectral CT imaging results in a significant reduction of streak artefacts produced by beam-hardening in mild and moderate artefacts by improving CT number accuracy, SNRs and CNRs, while decreasing noise values in a total hip arthroplasty phantom. An optimal monochromatic energy of 130keV was found ranging from 74keV to 150keV for different unilateral and bilateral hip prostheses consisting of different metal alloys. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

[Long-term observation of 920 porcelain fused to metal prostheses].

PubMed

Jiang, Yong-Lin; Sun, Jian; Weng, Wei-Min; Zhang, Fu-Qiang

2006-10-01

To evaluate the long-term clinical results of porcelain fused to metal prostheses. Since January 1995, 920 porcelain fused to metal prostheses were fabricated. The long-term outcome were evaluated according to the condition of the prosthese, abutment and the periodontal tissue in the respects of successful rate and causes of failure. 74 patients were found to be during the follow up period, including 36 anterior crowns (46 units), 18 posterior crowns (22 units), 12 percentage of anterior bridges and 8 posterior bridges. The overall failure rate was 8.04%, 4.84% for crown, 8.77% for bridge. The failed prostheses was 5.39%. Porcelain fused to metal prostheses is an ideal method for restoration. The standard process both for the clinician and the technician must be obeyed to improve the success rate.

[Muscle efficiency in total shoulder prosthesis implantation: dependence on position of the humeral head and rotator cuff function].

PubMed

Klages, A; Hurschler, C; Wülker, N; Windhagen, H

2001-09-01

Modern shoulder prostheses permit an anatomic reconstruction of the joint, although the biomechanical advantages are not proven. The goal of this study was to investigate the relationship between position of the humeral head and function of the shoulder prosthesis (muscle efficiency). Shoulder elevation-motion and rotator cuff defects were simulated in vitro in a robot-assisted shoulder simulator. The EPOCA Custom Offset shoulder prosthesis (Argomedical AG, Cham, CH) was implanted in seven normal shoulders (77 +/- 20 kg, 55 +/- 14 years). Active elevation was simulated by hydraulic cylinders, and scapulothoratic motion by a specially programmed industrial robot. Muscle efficiency (elevation-angle/muscle-force of the deltoid muscle) was measured in anatomic (ANA), medialised (MED) and lateralised (LAT) positions of the humeral head, with or without rotator cuff muscle deficiency. Medialisation increased efficiency by 0.03 +/- 0.04 deg/N (p = 0.022), lateralisation decreased it by 0.04 +/- 0.06 deg/N (p = 0.009). Supraspinatus muscle deficiency increased the deltoid force required to elevate the arm, and thus decreased efficiency (ANA p = 0.091, MED p = 0.018, LAT p = 0.028). The data confirm that the position of the humeral head affects the mechanics of total shoulder arthroplasty. Medialisation increases efficiency of the deltoid muscle and may prove useful in compensating isolated supraspinatus muscle deficiency. Lateralisation, in contrast, leads to an unfavorable situation.

Alternatives to amputation.

PubMed Central

Lendrum, J.

1980-01-01

Alternatives to conventional skin flap cover for limb wounds extend both the number and type of defects which can now be closed with reconstruction of both form and function for patients who might otherwise come to amputation. The old adage that where a sinus leads to dead or foreign material it can only be closed after removal of that dead or foreign material is no longer true. The number of patients coming to above-knee amputation after prosthetic replacement of the knee joint could be reduced by muscle flap cover of exposed arthroplasty prostheses. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7377695

Combined tooth-implant-supported telescopic prostheses in a midterm follow-up of > 2 years.

PubMed

Joda, Tim

2013-01-01

The aim of this trial was to evaluate telescopic-retained prostheses on teeth and implants. Ten patients with a mean of 2.8 teeth received strategic implants to achieve triangular/quadrangular support. Survival and complication rates were estimated for telescopic abutments and prostheses. After a mean observation period of > 2 years, no abutment was lost and all prostheses were in function. Complication rates were low, and maintenance services were limited to minor interventions. Combined tooth-implant-retained telescopic prostheses improve prosthetic support and offer successful function over a midterm period in patients with a severely reduced dentition.

A Meta-Analysis Examining Differences in Short-Term Outcomes Between Sutureless and Conventional Aortic Valve Prostheses.

PubMed

Hurley, Eoghan T; O'Sullivan, Katie E; Segurado, Ricardo; Hurley, John P

2015-01-01

Sutureless aortic valve prostheses are anchored by radial force in a mechanism similar to that of transcatheter aortic valve implantation. Transcatheter aortic valve implantation is associated with an increased permanent pacemaker (PPM) requirement in a significant proportion of patients. We undertook a meta-analysis to examine the incidence of PPM insertion associated with sutureless compared with conventional surgical aortic valve replacement. A systematic review was conducted in accordance with the Prisma guidelines. All searches were performed on August 10, 2014. Studies between 2007 and 2014 were included in the search. A total of 832 patients were included in the sutureless group and 3,740 in the conventional group. Aortic cross-clamp (39.8 vs 62.4 minutes; P < 0.001) and cardiopulmonary bypass (64.9 vs 86.7 minutes; P = 0.002) times were shorter in the sutureless group. Permanent pacemaker implantation rate was higher in the sutureless cohort (9.1% vs 2.4%; P = 0.025). Sutureless aortic valve prostheses are associated with significantly shorter cardiopulmonary bypass and aortic cross-clamp times and a higher incidence of PPM insertion than conventional. Further investigation of the prognostic significance is required.

[Application of negative molds technology based on three-dimensional printing in digital maxillofacial prostheses].

PubMed

Gu, X Y; Chen, X B; Jiao, T; Zhang, F Q; Jiang, X Q

2017-06-09

Objective: To explore a digital negative molds technique based on three-dimensional (3D) printing to assist in the manufacture of maxillofacial prostheses, and to improve the deficiency of the current clinical treatment. Methods: Seventeen patients with maxillofacial defects (including nasal defects, orbital defects, cheek defects, auricle defect) were scanned by means of facial optical scanning and computer tomography (CT). The 3D models were then reconstructed and global registration was made to merge the reconstructed models into a new digital model for 3D design. The 3D design of the prostheses was implemented in software. The mechanical connection structure was designed by forward engineering technology for 3 patients with intra-oral defects in maxilla who needed to make removable partial dentures, so that the silicone prostheses and removable partial denture could be combined. The removable partial dentures were made by conventional method and connected with the prostheses. According to the 3D data of the prostheses, the digital negative molds were designed, and the 3D printing technology was used to finish the processing of the resin molds. Silicone for prostheses were filled and cured in the resin molds to fabricate the clinical restorations for the patients. The margin adaptation and retention of the prostheses was detected. Results: Twenty patients with varying degrees of maxillofacial defects were rehabilitated using the courses developed in the study. All patients reported no pain or discomfort during the treatment; and they were satisfied with the final prostheses of the shape, color, retention, stability, etc. Eighteen of the prostheses showed good marginal adaptation, and sixteen of the prostheses showed good retention effect. Conclusions: The digital negative molds technique used in this study could greatly reduce the intensity of manual operation and provided a good therapeutic effect for patients with maxillofacial defects.

Anthropometric and Mass Distribution Characteristics of the Adult Female. Revised

DTIC Science & Technology

1983-09-01

syst ms, and development of body prostheses. 17. Key Words 18. Distribution Statement Anthropometry , Anatomical Axis, Body Document is available to the...COLLECTION............ . . . ....................... 3 The Subjects ..................................... 3 Anthropometry ...OF TAB&ES Table No. Anthropometry and Mass Distribution Data for the Total Body and Its Segment4: 1 Head

Comparison of bone-anchored prostheses and socket prostheses for patients with a lower extremity amputation: a systematic review.

PubMed

Leijendekkers, Ruud A; van Hinte, Gerben; Frölke, Jan Paul; van de Meent, Hendrik; Nijhuis-van der Sanden, Maria W G; Staal, J Bart

2017-06-01

This study aimed to provide an overview of a) the used measurement instruments in studies evaluating effects on quality of life (QoL), function, activity and participation level in patients with a lower extremity amputation using bone-anchored prostheses compared to socket prostheses and b) the effects themselves. A systematic literature search was conducted in MEDLINE, Cochrane, EMBASE, CINAHL and Web of Science. Included studies compared QoL, function, activity and/or participation level in patients with bone-anchored or socket prostheses. A best-evidence synthesis was performed. Out of 226 studies, five cohort and two cross-sectional studies were eligible for inclusion, all had methodological shortcomings. These studies used 10 different measurement instruments and two separate questions to assess outcome. Bone-anchored prostheses were associated with better condition-specific QoL and better outcomes on several of the physical QoL subscales, outcomes on the physical bodily pain subscale were inconclusive. Outcomes on function and activity level increased, no change was found at participation level. The level of evidence was limited. There is a need for a standard set of instruments. There was limited evidence that bone-anchored prostheses resulted in higher QoL, function and activity levels than socket prostheses, in patients with socket-related problems. Implications for Rehabilitation Use of bone-anchored prostheses in combination with intensive outpatient rehabilitation may improve QoL, function and activity level compared with socket prosthesis use in patients with a transfemoral amputation and socket-related problems. All clinicians and researchers involved with bone-anchored prostheses should use and publish data on QoL, function, activity and participation level. There needs to be an agreement on a standard set of instruments so that interventions for patients with a lower extremity amputation are assessed consistently.

[Evolution of the number and type of penile prostheses implanted in France for erectile dysfunction: Analysis of French national coding database (2006-2013)].

PubMed

Lipsker, A; Saljoghi, R; Lecuelle, D; Caillet, K; Alezra, E; Le Roux, F; Demailly, M; Saint, F

2016-09-01

Patients who are not responding to injectable and/or vacuum oral pharmacological treatments can receive a penile prosthesis. Three types of penile prostheses are used in France: rigid, semi-rigid and inflatable prostheses 3-piece or 2-piece. We have assessed the National surgical insertion practices between 2006 and 2013 (number of prostheses insertions, types, procedure locations, number of surgeons and distribution [public or private sectors]). Data analysis from the French Technical Agency of Information on Hospitals (ATIH) (2006-2013) using the common classification of medical acts (CCAM) and after code extractions related to this surgery (JHLA002, JHLA003, JHLA004). Between 2006 and 2013, the number of penile implants in France doubled (307 to 633), inflatable penile prostheses with an extracavernous component remained the most frequently used (87 %) (228 to 552) (+142 %). The use of semi-rigid prostheses declined by 26.7 %. The distribution between the private and public sector was close to 1 in 2013. More than half of French penile prostheses were implanted in three regions (Île-de-France, Languedoc-Roussillon, Rhône-Alpes). Nearly 62 % of surgeons implanted only one or two three-compartment prostheses in 2013. The number of penile prostheses in France doubled between 2006 and 2013. Three regions were particularly active as far as this surgery is concerned (Île-de-France, Languedoc-Roussillon, Rhône-Alpes). They were boosted by 5 surgeons with more than 20 prostheses surgeries a year. 4. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Dual jaw treatment of edentulism using implant-supported monolithic zirconia fixed prostheses.

PubMed

Altarawneh, Sandra; Limmer, Bryan; Reside, Glenn J; Cooper, Lyndon

2015-01-01

This case report describes restoration of the edentulous maxilla and mandible with implant supported fixed prostheses using monolithic zirconia, where the incisal edges and occluding surfaces were made of monolithic zirconia. Edentulism is a debilitating condition that can be treated with either a removable or fixed dental prosthesis. The most common type of implant-supported fixed prosthesis is the metal acrylic (hybrid), with ceramo-metal prostheses being used less commonly in complete edentulism. However, both of these prostheses designs are associated with reported complications of screw loosening or fracture and chipping of acrylic resin and porcelain. Monolithic zirconia implant-supported fixed prostheses have the potential for reduction of such complications. In this case, the CAD/CAM concept was utilized in fabrication of maxillary and mandibular screw-retained implant-supported fixed prostheses using monolithic zirconia. Proper treatment planning and execution coupled with utilizing advanced technologies contributes to highly esthetic results. However, long-term studies are required to guarantee a satisfactory long-term outcome of this modality of treatment. This case report describes the clinical and technical procedures involved in fabrication of maxillary and mandibular implant-supported fixed prostheses using monolithic zirconia as a treatment of edentulism, and proposes the possible advantages associated with using monolithic zirconia in eliminating dissimilar interfaces in such prostheses that are accountable for the most commonly occurring technical complication for these prostheses being chipping and fracture of the veneering material. © 2015 Wiley Periodicals, Inc.

Tribological measurements on a Charnley-type artificial hip joint

NASA Technical Reports Server (NTRS)

Jones, W. R., Jr.

1983-01-01

A total hip simulator was used to determine the friction and wear properties of Charnley-type (316L stainless steel balls and sterile ultrahigh molecular weight polyethylene cups) hip prostheses. Three different sets of specimens were tested to 395,000, 101,500 and 233,000 walking cycles, respectively. All tests were run unlubricated, at ambient conditions (22 to 26 C, 30 to 50 percent relative humidity), at 30 walking cycles per minute, under a dynamic load simulating walking. Polyethylene cup wear rates ranged from 1.4 to 39 ten billions cu m which corresponds to dimensional losses of 4.0 to 11 microns per year. Although these wear rates are lower than those obtained from other hip simulators and from in vivo X-ray measurements, they are comparable when taking run-in and plastic deformation into account. Maximum tangential friction forces ranged from 93 to 129 N under variable load (267 to 3090 N range) and from 93 to 143 N under a static load of 3090 N. A portion of one test 250,000 walking cycles) run under dry air ( 1 percent relative humidity) yielded a wear rate almost 6 times greater than that obtained under wet air ( 70 percent relative humidity) conditions.

Limitations of titanium dioxide and aluminum oxide as ossicular replacement materials: an evaluation of the effects of porosity on ceramic prostheses.

PubMed

Trabandt, Nicolaus; Brandes, Gudrun; Wintermantel, Erich; Lenarz, Thomas; Stieve, Martin

2004-09-01

Because the performance of titanium dioxide (TiO2) has not yet been assessed in the unique environment of the middle ear, its role as an ossicular replacement prototype in the form of a total ossicular replacement prosthesis (TORP) was tested and compared with aluminum oxide (Al2O3), once considered to be a suitable implant material. Ossiculoplasty was performed by implanting TORPs into the tympanic cavities of rabbits. After an implantation period of 28, 84, or 300 days, the petrous bones were extracted, whereby the biocompatibility of the prostheses was examined using light microscopy and scanning electron microscopy to determine morphologic changes in situ. Proper implant placement and functionality was tested via manual manipulation. Mucosa was seen covering most of the implants by day 84. Inflammatory cells were not observed in any of the specimens examined. The macroporous TiO2 TORPs were subjected to osseous infiltration, material dissolution, and fragmentation, whereas the microporous TiO2 implants were subjected to an increasing frequency of fissure formations. The Al2O3 prostheses demonstrated signs of material dissolution by producing encapsulated aggregates during the experimental trial period. Neither the macroporous nor microporous oxide ceramics were able to withstand the oscillatory stress to which they were continually subjected. Although porosity allows for the rapid integration of an implant material into a biological environment, its properties are not suited to fulfill the requirements of strength and long-term stability, which are demanded of middle ear prostheses.

Two-stage reimplantation for treating prosthetic shoulder infections.

PubMed

Sabesan, Vani J; Ho, Jason C; Kovacevic, David; Iannotti, Joseph P

2011-09-01

Two-stage reimplantation for prosthetic joint infection reportedly has the lowest risk for recurrent infection. Most studies to date have evaluated revision surgery for infection using an anatomic prosthetic. As compared with anatomic prostheses, reverse total shoulder arthroplasty is reported to have a higher rate of infection. We determined reinfection rates, functional improvement, types and rates of complications, and influence of rotator cuff tissue on function for two-stage reimplantation for prosthetic joint infection treated with reverse shoulder arthroplasty. We retrospectively reviewed 27 patients treated with a two-stage reimplantation for prosthetic shoulder infection using a uniform protocol for management of infection; of these, 17 had reverse shoulder arthroplasty at second-stage surgery. Types of organisms cultured, recurrence rates, complications, function, and radiographic followup were reviewed for all patients. One of the 17 patients had recurrence of infection. The mean (± SD) Penn shoulder scores for patients treated with reverse shoulder arthroplasty improved from 24.9 ± 22.3 to 66.4 ± 20.8. The average motion at last followup was 123° ± 33° of forward flexion and 26° ± 8° of external rotation in patients treated with a reverse shoulder arthroplasty. The major complication rate was 35% in reverse shoulder arthroplasty, with five dislocations and one reinfection. There was no difference in final Penn score between patients with and without external rotation weakness. Shoulder function and pain improved in patients treated with a second-stage reimplantation of a reverse prosthesis and the reinfection rate was low. Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence.

Influence of gamma-irradiation sterilization and temperature on the fracture toughness of ultra-high-molecular-weight polyethylene.

PubMed

Pascaud, R S; Evans, W T; McCullagh, P J; FitzPatrick, D P

1997-05-01

Surface damage of the tibial plateau components of knee prostheses made from medical grade ultra-high-molecular-weight polyethylene (UHMW-PE) has been attributed to delamination wear caused by a fatigue fracture mechanism. It has been proposed that factors such as component design and method of sterilization contribute to such failure mechanisms. Understanding the fracture behaviour of UHMW-PE is therefore critical in optimizing the in vivo life-span of total joint components. The elastic-plastic fracture toughness parameter J was consequently determined for a commercial UHMW-PE at ambient and body temperatures, before and after gamma-irradiation sterilization in air at a minimum dose of 29 kGy. Both ductile stability theory and experimental data suggest that cracks propagate in a stable manner, although stability is affected by the sterilization process. Sterilization with gamma-irradiation results in a loss in fracture toughness JIc of 50% and a decrease in tearing modulus (Tm) of 30%. This dramatic reduction could result in a 50% decrease in the residual strength of the components, maximum permissible crack size under service loading and service life (assuming flaws such as fusion defects exist). The time required for a crack to grow from its original size to the maximum permissible size could be decreased by 30%, resulting in earlier failure. In terms of the design of joint replacement components the critical factor to envisage is the design stress level, which should be halved to account for the irradiation process. A scanning electron microscope study reveals that the material fails in layers parallel to the fracture surface.

Microbial biofilms on facial prostheses.

PubMed

Ariani, Nina; Vissink, Arjan; van Oort, Robert P; Kusdhany, Lindawati; Djais, Ariadna; Rahardjo, Tri Budi W; van der Mei, Henny C; Krom, Bastiaan P

2012-01-01

The composition of microbial biofilms on silicone rubber facial prostheses was investigated and compared with the microbial flora on healthy and prosthesis-covered skin. Scanning electron microscopy showed the presence of mixed bacterial and yeast biofilms on and deterioration of the surface of the prostheses. Microbial culturing confirmed the presence of yeasts and bacteria. Microbial colonization was significantly increased on prosthesis-covered skin compared to healthy skin. Candida spp. were exclusively isolated from prosthesis-covered skin and from prostheses. Biofilms from prostheses showed the least diverse band-profile in denaturing gradient gel electrophoresis (DGGE) whereas prosthesis-covered skin showed the most diverse band-profile. Bacterial diversity exceeded yeast diversity in all samples. It is concluded that occlusion of the skin by prostheses creates a favorable niche for opportunistic pathogens such as Candida spp. and Staphylococcus aureus. Biofilms on healthy skin, skin underneath the prosthesis and on the prosthesis had a comparable composition, but the numbers present differed according to the microorganism.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, G.B.; Kiraly, R.J.; Nose, Y.

The objective of the study is to define the human thorax in a quantitative statistical manner such that the information will be useful to the designers of cardiac prostheses, both total replacement and assist devices. This report pertains specifically to anatomical parameters relevant to the total cardiac prosthesis. This information will also be clinically useful in that the proposed recipient of a cardiac prosthesis can by simple radiography be assured of an adequate fit with the prosthesis prior to the implantation.

Nano-Material Aspects of Shock Absorption in Bone Joints

PubMed Central

Tributsch, H; Copf, F; Copf, p; Hindenlang, U; Niethard, F.U; Schneider, R

2010-01-01

This theoretical study is based on a nano-technological evaluation of the effect of pressure on the composite bone fine structure. It turned out, that the well known macroscopic mechano-elastic performance of bones in combination with muscles and tendons is just one functional aspect which is critically supported by additional micro- and nano- shock damping technology aimed at minimising local bone material damage within the joints and supporting spongy bone material. The identified mechanisms comprise essentially three phenomena localised within the three–dimensional spongy structure with channels and so called perforated flexible tensulae membranes of different dimensions intersecting and linking them. Kinetic energy of a mechanical shock may be dissipated within the solid-liquid composite bone structure into heat via the generation of quasi-chaotic hydromechanic micro-turbulence. It may generate electro-kinetic energy in terms of electric currents and potentials. And the resulting specific structural and surface electrochemical changes may induce the compressible intra-osseal liquid to build up pressure dependent free chemical energy. Innovative bone joint prostheses will have to consider and to be adapted to the nano-material aspects of shock absorption in the operated bones. PMID:21625375

Amputation rehabilitation and prosthetic restoration. From surgery to community reintegration.

PubMed

Esquenazi, Alberto

The purpose of this review is to summarize the literature related to the advances that have taken place in the management and rehabilitation care of limb amputation. Prostheses for the lower and upper limb amputee have changed greatly over the past several years, with advances in components, socket fabrication and fitting techniques, suspension systems and sources of power and electronic controls. Higher levels of limb amputation can now be fitted with functional prostheses, which allow more patients to achieve independent life styles. This is of particular importance for the multi-limb amputee. The rehabilitation of more traditional lower limb levels of amputation have also greatly benefited from the technological advances including energy storing feet, electronic control hydraulic knees, ankle rotators and shock absorbers to mention a few. For the upper limb amputee, myoelectric and proportional controlled terminal devices and elbow joints are now used routinely in some rehabilitation facilities. Experimental prosthetic fitting techniques and devices such as the use of osseo-implantation for suspension of the prosthesis, tension control hands or electromagnetic fluids for knee movement control will also be briefly discussed in this paper. It is possible to conclude from this review that many advances have occurred that have greatly impacted the functional outcomes of patients with limb amputation.

Computer-aided dental prostheses construction using reverse engineering.

PubMed

Solaberrieta, E; Minguez, R; Barrenetxea, L; Sierra, E; Etxaniz, O

2014-01-01

The implementation of computer-aided design/computer-aided manufacturing (CAD/CAM) systems with virtual articulators, which take into account the kinematics, constitutes a breakthrough in the construction of customised dental prostheses. This paper presents a multidisciplinary protocol involving CAM techniques to produce dental prostheses. This protocol includes a step-by-step procedure using innovative reverse engineering technologies to transform completely virtual design processes into customised prostheses. A special emphasis is placed on a novel method that permits a virtual location of the models. The complete workflow includes the optical scanning of the patient, the use of reverse engineering software and, if necessary, the use of rapid prototyping to produce CAD temporary prostheses.

A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom

NASA Astrophysics Data System (ADS)

Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

2015-10-01

The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

A structurally decoupled mechanism for measuring wrist torque in three degrees of freedom.

PubMed

Pan, Lizhi; Yang, Zhen; Zhang, Dingguo

2015-10-01

The wrist joint is a critical part of the human body for movement. Measuring the torque of the wrist with three degrees of freedom (DOFs) is important in some fields, including rehabilitation, biomechanics, ergonomics, and human-machine interfacing. However, the particular structure of the wrist joint makes it difficult to measure the torque in all three directions simultaneously. This work develops a structurally decoupled instrument for measuring and improving the measurement accuracy of 3-DOF wrist torque during isometric contraction. Three single-axis torque sensors were embedded in a customized mechanical structure. The dimensions and components of the instrument were designed based on requirement of manufacturability. A prototype of the instrument was machined, assembled, integrated, and tested. The results show that the structurally decoupled mechanism is feasible for acquiring wrist torque data in three directions either independently or simultaneously. As a case study, we use the device to measure wrist torques concurrently with electromyography signal acquisition in preparation for simultaneous and proportional myoelectric control of prostheses.

Effect of the Distal Femoral Joint Line on Ligament Tensions in Flexion with Cruciate-Retaining Total Knee Prostheses.

PubMed

Narayanan, Rajkishen; Lenz, Nathaniel; Werner, Jordan Alexander; Cross, Michael B; Hughes, Dean; Laster, Scott; Schwarzkopf, Ran

2018-04-13

Proper ligament tension in knee flexion within cruciate-retaining (CR) total knee arthroplasty has long been associated with clinical success; however, traditional balancing principles have assumed that the distal femoral joint line (DFJL) affects only extension. The purpose of this study was to determine the effect DFJL may have on ligament strains and tibiofemoral kinematics of CR knee designs in flexion. A computational analysis was performed using a musculoskeletal modeling system for two different knee implants, the high-flex CR (HFCR) and guided-motion CR (GMCR). Tibiofemoral kinematics and ligament strain were measured at 90-degree knee flexion while the implants' DFJL was incrementally shifted proximally. Femoral implant position and kinematics were used to determine the femur's anteroposterior position relative to the tibia. The change in the femoral medial condyle position relative to the tibia was 0.33 mm and 0.53 mm more anterior per each 1-mm elevation of the DFJL for HFCR and GMCR, respectively. The change in the lateral condyle position was 0.20 mm more anterior and 0.06 mm more posterior for HFCR and GMCR, respectively. The strain in the lateral and medial collateral ligaments changed minimally with elevation of the DFJL. In both implants, strain increased in the anterior lateral and posterior medial bundles of the posterior collateral ligament with elevation of the DFJL, whereas strain decreased in the iliotibial band and iliotibial patellar band. Our findings suggest that DFJL affects ligament tension at 90-degree knee flexion and therefore flexion balance for CR implants. Elevating the DFJL to address tight extension space in a CR knee while flexion space is well balanced could result in increased flexion tension especially when the flexion-extension mismatch is large. To achieve balanced flexion and extension, the amount of DFJL elevation may need to be reduced. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Reconstruction with 3D-printed pelvic endoprostheses after resection of a pelvic tumour.

PubMed

Liang, H; Ji, T; Zhang, Y; Wang, Y; Guo, W

2017-02-01

The aims of this retrospective study were to report the feasibility of using 3D-printing technology for patients with a pelvic tumour who underwent reconstruction. A total of 35 patients underwent resection of a pelvic tumour and reconstruction using 3D-printed endoprostheses between September 2013 and December 2015. According to Enneking's classification of bone defects, there were three Type I lesions, 12 Type II+III lesions, five Type I+II lesions, two Type I+II+III lesions, ten type I+II+IV lesions and three type I+II+III+IV lesions. A total of three patients underwent reconstruction using an iliac prosthesis, 12 using a standard hemipelvic prosthesis and 20 using a screw-rod connected hemipelvic prosthesis. All patients had an en bloc resection. Margins were wide in 15 patients, marginal in 14 and intralesional in six. After a mean follow-up of 20.5 months (6 to 30), 25 patients survived without evidence of disease, five were alive with disease and five had died from metastatic disease. Complications included seven patients with delayed wound healing and two with a dislocation of the hip. None had a deep infection. For the 30 surviving patients, the mean Musculoskeletal Society 93 score was 22.7 (20 to 25) for patients with an iliac prosthesis, 19.8 (15 to 26) for those with a standard prosthesis, and 17.7 (9 to 25) for those with a screw-rod connected prosthesis. The application of 3D-printing technology can facilitate the precise matching and osseointegration between implants and the host bone. We found that the use of 3D-printed pelvic prostheses for reconstruction of the bony defect after resection of a pelvic tumour was safe, without additional complications, and gave good short-term functional results. Cite this article: Bone Joint J 2017;99-B:267-75. ©2017 The British Editorial Society of Bone & Joint Surgery.

Augmented Reality Visualization with Use of Image Overlay Technology for MR Imaging–guided Interventions: Assessment of Performance in Cadaveric Shoulder and Hip Arthrography at 1.5 T

PubMed Central

Fritz, Jan; U-Thainual, Paweena; Ungi, Tamas; Flammang, Aaron J.; Fichtinger, Gabor; Iordachita, Iulian I.

2012-01-01

Purpose: To prospectively assess overlay technology in providing accurate and efficient targeting for magnetic resonance (MR) imaging–guided shoulder and hip joint arthrography. Materials and Methods: A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imager. A total of 24 shoulder joint and 24 hip joint injections were planned in 12 human cadavers. Two operators (A and B) participated, each performing procedures on different cadavers using image overlay guidance. MR imaging was used to confirm needle positions, monitor injections, and perform MR arthrography. Accuracy was assessed according to the rate of needle adjustment, target error, and whether the injection was intraarticular. Efficiency was assessed according to arthrography procedural time. Operator differences were assessed with comparison of accuracy and procedure times between the operators. Mann-Whitney U test and Fisher exact test were used to assess group differences. Results: Forty-five arthrography procedures (23 shoulders, 22 hips) were performed. Three joints had prostheses and were excluded. Operator A performed 12 shoulder and 12 hip injections. Operator B performed 11 shoulder and 10 hip injections. Needle adjustment rate was 13% (six of 45; one for operator A and five for operator B). Target error was 3.1 mm ± 1.2 (standard deviation) (operator A, 2.9 mm ± 1.4; operator B, 3.5 mm ± 0.9). Intraarticular injection rate was 100% (45 of 45). The average arthrography time was 14 minutes (range, 6–27 minutes; 12 minutes [range, 6–25 minutes] for operator A and 16 minutes [range, 6–27 min] for operator B). Operator differences were not significant with regard to needle adjustment rate (P = .08), target error (P = .07), intraarticular injection rate (P > .99), and arthrography time (P = .22). Conclusion: Image overlay technology provides accurate and efficient MR guidance for successful shoulder and hip arthrography in human cadavers. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112640/-/DC1 PMID:22843764

Quantification of dental prostheses on cone‐beam CT images by the Taguchi method

PubMed Central

Kuo, Rong‐Fu; Fang, Kwang‐Ming; TY, Wong

2016-01-01

The gray values accuracy of dental cone‐beam computed tomography (CBCT) is affected by dental metal prostheses. The distortion of dental CBCT gray values could lead to inaccuracies of orthodontic and implant treatment. The aim of this study was to quantify the effect of scanning parameters and dental metal prostheses on the accuracy of dental cone‐beam computed tomography (CBCT) gray values using the Taguchi method. Eight dental model casts of an upper jaw including prostheses, and a ninth prosthesis‐free dental model cast, were scanned by two dental CBCT devices. The mean gray value of the selected circular regions of interest (ROIs) were measured using dental CBCT images of eight dental model casts and were compared with those measured from CBCT images of the prosthesis‐free dental model cast. For each image set, four consecutive slices of gingiva were selected. The seven factors (CBCTs, occlusal plane canting, implant connection, prosthesis position, coping material, coping thickness, and types of dental restoration) were used to evaluate scanning parameter and dental prostheses effects. Statistical methods of signal to noise ratio (S/N) and analysis of variance (ANOVA) with 95% confidence were applied to quantify the effects of scanning parameters and dental prostheses on dental CBCT gray values accuracy. For ROIs surrounding dental prostheses, the accuracy of CBCT gray values were affected primarily by implant connection (42%), followed by type of restoration (29%), prostheses position (19%), coping material (4%), and coping thickness (4%). For a single crown prosthesis (without support of implants) placed in dental model casts, gray value differences for ROIs 1–9 were below 12% and gray value differences for ROIs 13–18 away from prostheses were below 10%. We found the gray value differences set to be between 7% and 8% for regions next to a single implant‐supported titanium prosthesis, and between 46% and 59% for regions between double implant‐supported, nickel‐chromium alloys (Ni‐Cr) prostheses. Quantification of the effect of prostheses and scanning parameters on dental CBCT gray values was assessed. PACS numbers: 87.59.bd, 87.57Q PMID:26894354

Comparison of Fixed Dental Prostheses with Zirconia and Metal Frameworks: Five-Year Results of a Randomized Controlled Clinical Trial.

PubMed

Sailer, Irena; Balmer, Marc; Hüsler, Jürg; Hämmerle, Christoph Hans Franz; Känel, Sarah; Thoma, Daniel Stefan

The aim of this study was to test whether posterior zirconia-ceramic (ZC) and metal-ceramic (MC) fixed dental prostheses (FDPs) exhibit similar survival and technical/biologic complication rates. A total of 58 patients in need of 76 posterior FDPs were randomly assigned to receive 40 ZC and 36 MC FDPs. The restorations were examined at baseline (cementation) and yearly for 5 years. Technical and biologic outcomes were compared. The independent treatment groups were compared with nonparametric Mann-Whitney test for metric variables and with Fisher exact test for categoric data. A total of 52 patients with 40 ZC and 29 MC FDPs were examined at 5 years. No FDP failed during the 5 years; 2 ZC FDPs failed at 65.4 and 73.3 months. Debonding occurred at 3 ZC FDPs. Technical outcomes (modified US Public Health Service criteria) and general periodontal parameters did not show significant differences between ZC and MC FDPs. ZC FDPs exhibited similar outcomes to MC FDPs based on 5-year survival estimates. The majority of technical and biologic outcome measures were not significantly different.

Comparative Study Between M6-C and Mobi-C Cervical Artificial Disc Replacement: Biomechanical Outcomes and Comparison with Normative Data.

PubMed

Pham, My; Phan, Kevin; Teng, Ian; Mobbs, Ralph J

2018-05-01

Cervical spondylosis affects a huge proportion of the middle-aged population. Degenerative changes can occur in multiple regions of the cervical spine typically affecting the joints, intervertebral discs and endplates. These changes lead to compression of adjacent nervous structures, which results in radiculopathic and myelopathic pain. Various treatment modalities are currently available with non-surgical approaches the initial go to if there is no symptomatic cord compression. Anterior cervical discectomy and fusion, or arthroplasty are the two common surgical approaches if non-surgical treatments fail to relieve symptoms of the patients or there are signs of central cord compression. However, studies have shown that there is an increased risk of adjacent segment disease related to fusion. Cervical disc arthroplasty aims to restore normal range of motion (ROM) in patients with pain and disability due to degenerative disc disease resistant to conservative care. Two common disc prostheses used include M6-C and Mobi-C. Both prostheses comprise a mobile polymer segment sandwiched between two metal endplates with mechanisms resembling an actual intervertebral disc. This study aims to compare the kinematics associated with these prostheses, against the normal range of motion in the non-degenerative population. Patients who underwent M6-C or Mobi-C disc replacements by the senior author from 2012 to 2015 were identified at a single tertiary institution. Routine 3-month postoperative lateral radiographs were analyzed for flexion and extension ROM angles at the involved vertebral level by two independent authors. Data was compared to previous published studies investigating cervical spine ROM of asymptomatic patients. There was no statistical significance in the difference of overall flexion range between M6-C and Mobi-C prostheses. However, overall range of extension of Mobi-C was greater compared to M6-C (P = 0.028). At C 5-6 , the range of flexion for both implants were similar but lesser compared to asymptomatic patients (P < 0.001). Range of extension was greater in the Mobi-C group (14.2° ± 5.1°) compared to the M6-C (7.3° ± 4.6°) (P = 0.0009). At C 6-7 , there were no statistical differences in both range of flexion and extension between the two prostheses and asymptomatic patients (P > 0.05). The early results regarding restoration of ROM following cervical arthroplasty using either M6-C or Mobi-C prosthesis are encouraging. Long-term follow-up studies are necessary to observe the change in ROM over time with physiological loading and wear patterns. © 2018 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Gram-negative prosthetic joint infection: outcome of a debridement, antibiotics and implant retention approach. A large multicentre study.

PubMed

Rodríguez-Pardo, D; Pigrau, C; Lora-Tamayo, J; Soriano, A; del Toro, M D; Cobo, J; Palomino, J; Euba, G; Riera, M; Sánchez-Somolinos, M; Benito, N; Fernández-Sampedro, M; Sorli, L; Guio, L; Iribarren, J A; Baraia-Etxaburu, J M; Ramos, A; Bahamonde, A; Flores-Sánchez, X; Corona, P S; Ariza, J

2014-11-01

We aim to evaluate the epidemiology and outcome of gram-negative prosthetic joint infection (GN-PJI) treated with debridement, antibiotics and implant retention (DAIR), identify factors predictive of failure, and determine the impact of ciprofloxacin use on prognosis. We performed a retrospective, multicentre, observational study of GN-PJI diagnosed from 2003 through to 2010 in 16 Spanish hospitals. We define failure as persistence or reappearance of the inflammatory joint signs during follow-up, leading to unplanned surgery or repeat debridement>30 days from the index surgery related death, or suppressive antimicrobial therapy. Parameters predicting failure were analysed with a Cox regression model. A total of 242 patients (33% men; median age 76 years, interquartile range (IQR) 68-81) with 242 episodes of GN-PJI were studied. The implants included 150 (62%) hip, 85 (35%) knee, five (2%) shoulder and two (1%) elbow prostheses. There were 189 (78%) acute infections. Causative microorganisms were Enterobacteriaceae in 78%, Pseudomonas spp. in 20%, and other gram-negative bacilli in 2%. Overall, 19% of isolates were ciprofloxacin resistant. DAIR was used in 174 (72%) cases, with an overall success rate of 68%, which increased to 79% after a median of 25 months' follow-up in ciprofloxacin-susceptible GN-PJIs treated with ciprofloxacin. Ciprofloxacin treatment exhibited an independent protective effect (adjusted hazard ratio (aHR) 0.23; 95% CI, 0.13-0.40; p<0.001), whereas chronic renal impairment predicted failure (aHR, 2.56; 95% CI, 1.14-5.77; p 0.0232). Our results confirm a 79% success rate in ciprofloxacin-susceptible GN-PJI treated with debridement, ciprofloxacin and implant retention. New therapeutic strategies are needed for ciprofloxacin-resistant PJI. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Implant design influences patient outcome after total knee arthroplasty: a prospective double-blind randomised controlled trial.

PubMed

Hamilton, D F; Burnett, R; Patton, J T; Howie, C R; Moran, M; Simpson, A H R W; Gaston, P

2015-01-01

Total knee arthroplasty (TKA) is an established and successful procedure. However, the design of prostheses continues to be modified in an attempt to optimise the functional outcome of the patient. The aim of this study was to determine if patient outcome after TKA was influenced by the design of the prosthesis used. A total of 212 patients (mean age 69; 43 to 92; 131 female (62%), 81 male (32%)) were enrolled in a single centre double-blind trial and randomised to receive either a Kinemax (group 1) or a Triathlon (group 2) TKA. Patients were assessed pre-operatively, at six weeks, six months, one year and three years after surgery. The outcome assessments used were the Oxford Knee Score; range of movement; pain numerical rating scales; lower limb power output; timed functional assessment battery and a satisfaction survey. Data were assessed incorporating change over all assessment time points, using repeated measures analysis of variance longitudinal mixed models. Implant group 2 showed a significantly greater range of movement (p = 0.009), greater lower limb power output (p = 0.026) and reduced report of 'worst daily pain' (p = 0.003) over the three years of follow-up. Differences in Oxford Knee Score (p = 0.09), report of 'average daily pain' (p = 0.57) and timed functional performance tasks (p = 0.23) did not reach statistical significance. Satisfaction with outcome was significantly better in group 2 (p = 0.001). These results suggest that patient outcome after TKA can be influenced by the prosthesis used. ©2015 The British Editorial Society of Bone & Joint Surgery.

Evaluation of metal-polymeric fixed partial prosthesis using optical coherence tomography

NASA Astrophysics Data System (ADS)

Sinescu, C.; Negrutiu, M. L.; Duma, V. F.; Marcauteanu, C.; Topala, F. I.; Rominu, M.; Bradu, A.; Podoleanu, A. Gh.

2013-11-01

Metal-Polymeric fixed partial prosthesis is the usual prosthetic treatment for many dental patients. However, during the mastication the polymeric component of the prosthesis is fractured and will be lost. This fracture is caused by the material defects or by the fracture lines trapped inside the esthetic components of the prosthesis. This will finally lead to the failure of the prosthetic treatment. Nowadays, there is no method of identification and forecast for the materials defects of the polymeric materials. The aim of this paper is to demonstrate the capability of Optical Coherence Tomography (OCT) as a non-invasive clinical method that can be used for the evaluation of metal-polymeric fixed partial prostheses. Twenty metal-polymeric fixed partial prostheses were used for this study. The esthetic component of the prostheses has been Adoro (Ivoclar). Optical investigations of the metal prostheses have revealed no material defects or fracture lines. All the prostheses were temporary cemented in the oral cavities of the patients for six month. The non-invasive method used for the investigations was OCT working in Time Domain mode at 1300 nm. The evaluations of the prostheses were performed before and after their cementation in the patient mouths. All the imagistic results were performed in 2D and than in 3D, after the reconstruction. The results obtained after the OCT evaluation allowed for the identification of 4 metal-polymeric fixed partial prostheses with material defects immediately after finishing the technological procedures. After 6 month in the oral environment other 3 fixed partial prostheses revealed fracture lines. In conclusion, OCT proved to be a valuable tool for the noninvasive evaluation of the metal-polymeric fixed partial prostheses.

Implant-level prostheses in the edentulous maxilla: a comparison with conventional abutment-level prostheses after 5 years of use.

PubMed

Hjalmarsson, Lars; Smedberg, Jan-Ivan; Pettersson, Mattias; Jemt, Torsten

2011-01-01

Long-term comparisons of frameworks at the implant or abutment level are not available, and knowledge of the clinical function of cobalt-chromium (Co-Cr) alloy frameworks is limited. Primarily, the aim of this study was to compare the 5-year clinical performance of frameworks with or without abutment connections to implants. Secondly, the outcomes of prostheses made from Co-Cr alloy with porcelain veneers to those made of commercially pure titanium (CP Ti) with acrylic veneers were compared. The test groups comprised patients treated with screw-retained fixed prostheses made at the implant level according to the Cresco method in either dental porcelain-veneered Co-Cr alloy (n = 15) or acrylic-veneered CP Ti (n = 25). A control group of 40 randomly selected patients were provided with prostheses made at the standard abutment level in CP Ti with acrylic veneers. For all patients, clinical and radiologic 5-year data were retrospectively collected and evaluated. Five-year implant cumulative survival rates (CSRs) were 98.6% and 97.6% for test and control groups, respectively (P > .05). No major differences in bone level were demonstrated between the groups after 5 years (P > .05). Significantly more complications occurred in the test groups compared to the control group (P < .01), with the most common complications being mucositis and fracture of veneers. After 5 years, the clinical outcomes of implant-level prostheses made of porcelain-veneered Co-Cr or acrylic-veneered CP Ti seem comparable to acrylic-veneered titanium prostheses made at the standard abutment level regarding implant CSR and bone levels. However, more complications were registered in implant-level prostheses compared to the standard abutment-level prostheses.

Identification of bacteria on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties by 16S rRNA gene sequencing and by microbiological culture

PubMed Central

Dempsey, Kate E; Riggio, Marcello P; Lennon, Alan; Hannah, Victoria E; Ramage, Gordon; Allan, David; Bagg, Jeremy

2007-01-01

It has been postulated that bacteria attached to the surface of prosthetic hip joints can cause localised inflammation, resulting in failure of the replacement joint. However, diagnosis of infection is difficult with traditional microbiological culture methods, and evidence exists that highly fastidious or non-cultivable organisms have a role in implant infections. The purpose of this study was to use culture and culture-independent methods to detect the bacteria present on the surface of prosthetic hip joints removed during revision arthroplasties. Ten consecutive revisions were performed by two surgeons, which were all clinically and radiologically loose. Five of the hip replacement revision surgeries were performed because of clinical infections and five because of aseptic loosening. Preoperative and perioperative specimens were obtained from each patient and subjected to routine microbiological culture. The prostheses removed from each patient were subjected to mild ultrasonication to dislodge adherent bacteria, followed by aerobic and anaerobic microbiological culture. Bacterial DNA was extracted from each sonicate and the 16S rRNA gene was amplified with the universal primer pair 27f/1387r. All 10 specimens were positive for the presence of bacteria by both culture and PCR. PCR products were then cloned, organised into groups by RFLP analysis and one clone from each group was sequenced. Bacteria were identified by comparison of the 16S rRNA gene sequences obtained with those deposited in public access sequence databases. A total of 512 clones were analysed by RFLP analysis, of which 118 were sequenced. Culture methods identified species from the genera Leifsonia (54.3%), Staphylococcus (21.7%), Proteus (8.7%), Brevundimonas (6.5%), Salibacillus (4.3%), Methylobacterium (2.2%) and Zimmermannella (2.2%). Molecular detection methods identified a more diverse microflora. The predominant genus detected was Lysobacter, representing 312 (60.9%) of 512 clones analysed. In all, 28 phylotypes were identified: Lysobacter enzymogenes was the most abundant phylotype (31.4%), followed by Lysobacter sp. C3 (28.3%), gamma proteobacterium N4-7 (6.6%), Methylobacterium SM4 (4.7%) and Staphylococcus epidermidis (4.7%); 36 clones (7.0%) represented uncultivable phylotypes. We conclude that a diverse range of bacterial species are found within biofilms on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties. PMID:17501992

Does location of rotation center in artificial disc affect cervical biomechanics?

PubMed

Mo, Zhongjun; Zhao, Yanbin; Du, Chengfei; Sun, Yu; Zhang, Ming; Fan, Yubo

2015-04-15

A 3-dimensional finite element investigation. To compare the biomechanical performances of different rotation centers (RCs) in the prevalent artificial cervical discs. Various configurations are applied in artificial discs. Design parameters may influence the biomechanics of implanted spine. The RC is a primary variation in the popular artificial discs. Implantation of 5 prostheses was simulated at C5-C6 on the basis of a validated finite element cervical model (C3-C7). The prostheses included ball-in-socket design with a fixed RC located on the inferior endplate (BS-FI) and on the superior endplate (BS-FS), with a mobile RC at the inferior endplate (BS-MI), dual articulation with a mobile RC between the endplates (DA-M), and sliding articulation with various RCs (SA-V). The spinal motions in flexion and extension served as a displacement loading at the C3 vertebrae. Total disc replacements reduced extension moment. The ball-in-socket designs required less flexion moment, whereas the flexion stiffness of the spines with DA-M and SA-V was similar to that of the healthy model. The contributions of the implanted level to the global motions increased in the total disc replacements, except in the SA-V and DA-M models (in flexion). Ball-in-socket designs produced severe stress distributions in facet cartilage, whereas DA-M and SA-V produced more severe stress distribution on the bone-implant interface. Cervical stability was extremely affected in extension and partially affected in flexion by total disc replacement. With the prostheses with mobile RC, cervical curvature was readjusted under a low follower load. The SA-V and BS-FS designs exhibited better performances in the entire segmental stiffness and in the stability of the operative level than the BS-MI and BS-FI designs in flexion. The 5 designs demonstrated varying advantages relative to the stress distribution in the facet cartilages and on the bone-implant interface. 5.

Morphometric evaluation of the knee in Chinese population reveals sexual dimorphism and age-related differences.

PubMed

Li, Ke; Cavaignac, Etienne; Xu, Wei; Cheng, Qiang; Telmon, Nobert; Huang, Wei

2018-02-20

Morphologic data of the knee is very important in the design of total knee prostheses. Generally, the designs of the total knee prostheses are based on the knee anatomy of Caucasian population. Moreover, in forensic medicine, a person's age and sex might be estimated by the shape of their knees. The aim of this study is to utilize three-dimensional morphometric analysis of the knee in Chinese population to reveal sexual dimorphism and age-related differences. Sexually dimorphic differences and age-related differences of the distal femur were studied by using geometric morphometric analysis of ten osteometric landmarks on three-dimensional reconstructions of 259 knees in Chinese population. General Procrustes analysis, PCA, and other discriminant analysis such as Mahalanobis and Goodall's F test were conducted for the knee to identify sexually dimorphism and age-related differences of the knee. The shape of distal femur between the male and female is significantly different. A difference between males and females in distal femur shape was identified by PCA; PC1 and PC2 accounted for 61.63% of the variance measured. The correct sex was assigned in 84.9% of cases by CVA, and the cross-validation revealed a 81.1% rate of correct sex estimation. The osteometric analysis also showed significant differences between the three age-related subgroups (< 40, 40-60, > 60 years, p < 0.005). This study showed both sex-related difference and age-related difference in the distal femur in Chinese population by 3D geometric morphometric analysis. Our bone measurements and geometric morphometric analysis suggest that population characteristics should be taken into account and may provide references for design of total knee prostheses in a Chinese population. Moreover, this reliable, accurate method could be used to perform diachronic and interethnic comparisons.

The use of interlocking prostheses for both temporary and definitive management of infected periprosthetic femoral fractures.

PubMed

Konan, Sujith; Rayan, Faizal; Manketelow, Andrew R J; Haddad, Fares S

2011-12-01

Infected periprosthetic fractures around total hip arthroplasties are an extremely challenging problem. We describe our experience of managing infected periprosthetic femoral fractures using interlocking long-stem femoral prostheses either as temporary functional spacers or as definitive implants. The Cannulock (Orthodesign, Christchurch, United Kingdom) uncoated stem was used in 12 cases, and the Kent hip prosthesis (Biomet Merck, Bridgend, United Kingdom), in 5 cases. Satisfactory outcome was noted in all cases, and in 11 cases, revision to a definitive stem has been undertaken after successful control of infection and fracture union. The use of interlocking stems offers a relatively appealing solution for a complex problem and avoids the complications that would be associated with resection of the entire femur or the use of large quantities of bone cement. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of Design Variants in Lower-Limb Prostheses on Gait Synergy

PubMed Central

Pitkin, Mark R.

2016-01-01

A lower-limb prosthesis is the mechanical device with which an amputee’s residual limb interacts with the walking surface. The pressure and shear forces that affect the residuum due to prosthesis use are the sources of pain, residual-limb skin problems and gait deviations. Direct approaches to reducing these problems include improving fit, alignment technique and socket design as well as increasing cushioning with socket liners. A summary of typical malalignments and their consequences is presented. The malalignments are considered sources of excessive moments applied to the residuum, which simplifies the analysis of a patient’s gait. A better design of prosthetic joints could improve prosthetic gait. This article addresses the key mechanical parameter of prosthetic joints, namely the dependence “moment of resistance/angle of deflection.” A mathematical model has been developed that links stresses on the residuum in transtibial amputees with the moment of resistance in the prosthetic ankle at the critical gait phases. Analysis of the model yields a substantial decrease in stresses on the residuum during the most demanding, load-bearing phase of stance if the moment of resistance in the ankle is similar to that seen in the biological ankle joint. Gait study shows use of the experimental rolling-joint prosthetic foot more closely simulates normal gait synergy than the SACH foot. PMID:27087763

Prostheses and orthoses for the foot and ankle.

PubMed

Rubin, G; Cohen, E

1988-07-01

The general nature and function of the AFO has been presented. These devices encompass the foot and leg crossing the ankle joint. They may insert into the shoe or attach to the shoe. The more recent AFOs are made of polypropylene and were formerly composed of steel. The indications for an AFO are for a basically ambulatory patient with problems walking, including various pathologic gaits especially drop-foot and spastic equinus. Other primary indications include ankle arthritis, Charcot foot, fractures, and post-surgery. Given the basic employment of AFOs to treat problems directly related to the foot, it is hoped that this introduction has stimulated practitioners to begin using this essential tool as an integral component of their practice.

Ageing, musculoskeletal health and work

PubMed Central

Palmer, Keith; Goodson, Nicola

2016-01-01

Changing demographics mean that many patients with soft tissue rheumatism, osteoarthritis, inflammatory arthritis, large joint prostheses, and age-related co-morbidities are seeking to work beyond the traditional retirement age. In this chapter we review the evidence on musculoskeletal health and work at older ages. We conclude that musculoskeletal problems are common in older workers and have a substantial impact on their work capacity. Factors that influence their job retention are described, together with approaches that may extend working life. Many gaps in evidence were found, notably on the health risks and benefits of continued work in affected patients and on which interventions work best. The roles of physicians and managers are also considered. PMID:26612237

Assessment of the mechanical performance of titanium cranial prostheses manufactured by super plastic forming and single point incremental forming

NASA Astrophysics Data System (ADS)

Sgambitterra, Emanuele; Piccininni, Antonio; Guglielmi, Pasquale; Ambrogio, Giuseppina; Fragomeni, Gionata; Villa, Tomaso; Palumbo, Gianfranco

2018-05-01

Cranial implants are custom prostheses characterized by quite high geometrical complexity and small thickness; at the same time aesthetic and mechanical requirements have to be met. Titanium alloys are largely adopted for such prostheses, as they can be processed via different manufacturing technologies. In the present work cranial prostheses have been manufactured by Super Plastic Forming (SPF) and Single Point Incremental Forming (SPIF). In order to assess the mechanical performance of the cranial prostheses, drop tests under different load conditions were conducted on flat samples to investigate the effect of the blank thickness. Numerical simulations were also run for comparison purposes. The mechanical performance of the cranial implants manufactured by SPF and SPIF could be predicted using drop test data and information about the thickness evolution of the formed parts: the SPIFed prosthesis revealed to have a lower maximum deflection and a higher maximum force, while the SPFed prostheses showed a lower absorbed energy.

Hip prostheses in young adults. Surface prostheses and short-stem prostheses.

PubMed

Gallart, X; Riba, J; Fernández-Valencia, J A; Bori, G; Muñoz-Mahamud, E; Combalia, A

The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Microflora on explanted silicone rubber voice prostheses: taxonomy, hydrophobicity and electrophoretic mobility.

PubMed

Neu, T R; Verkerke, G J; Herrmann, I F; Schutte, H K; Van der Mei, H C; Busscher, H J

1994-05-01

Silicone rubber voice prostheses are implants which are inserted in a non-sterile environment and therefore become quickly colonized by micro-organisms. The micro-organisms exist on the medical grade silicone rubber as mixed biofilms of bacteria and yeasts. A total of 79 bacterial and 39 yeast strains were isolated from these biofilms by soft ultrasonic treatment. Gram-positive/catalase-negative and Gram-positive/catalase-positive cocci represented the dominant bacterial strains. The yeasts were mainly Candida species. Further characterization of cell surface properties such as hydrophobicity by microbial adhesion to hexadecane and electrophoretic mobility showed a distinct difference when the bacterial strains were compared with the yeasts. The bacterial hydrophobicities ranged from 0 to 100% adhesion to hexadecane, whereas the yeast strains, especially the Candida albicans strains, all had markedly hydrophilic cell surfaces. A comparison of the electrophoretic mobilities showed also differences between bacteria and yeast. The values for the bacteria were found to be between -2.5 to -0.5 (10(-8) m2 V-1 s-1), whereas for the yeasts electrophoretic mobilities were more positive. Based on the adhesive properties of the isolated micro-organisms, strategies can now be developed to modify the properties of the silicone rubber to reduce biofilm formation on such prostheses.

Antibiotic cements in articular prostheses: current orthopaedic concepts.

PubMed

Langlais, F; Belot, N; Ropars, M; Thomazeau, H; Lambotte, J C; Cathelineau, G

2006-08-01

The possibilities and limits of antibiotic cements (ACs) have been assessed by many researchers. ACs are now approved by many drug agencies, including the US Food and Drug Administration (approval in 2003), with widespread use in prophylaxis and curative treatments. Laboratory experiments have achieved satisfactory antibiotic delivery without impairing the mechanical properties of ACs. Implantation in large animals (e.g. sheep) showed an antibiotic concentration in the bone cortex four times the minimal inhibitory concentration (MIC) 6 months after implantation. Human pharmacokinetics during total hip replacement (THR) show antibiotic concentrations 20 times the MIC in drainage fluids. No toxic concentrations have been detected in blood or urine, and no allergies, toxic effects, mechanical failures or selection of resistant microorganisms have been observed. Antibioprophylaxis has been assessed in prospective studies in over 1600 cases. In data from the Scandinavian arthroplasty registers, with an exhaustive follow-up of more than 240000 THRs, infection rate was reduced by ca. 50% (0.9% compared with 1.9%). In prostheses with severe infection, use of AC increases the infection control rate from 86% to 93% when using two-stage prosthetic exchanges. In moderate infection, a similar infection control rate (86%) was achieved either by two-stage exchange without local antibiotic or by one-stage exchange with AC; however, one-stage exchange achieved better functional results at lower cost and with reduced pain and hospital stay. Therefore, AC prophylaxis is widely used in countries with prostheses registers (Northern Europe), and use of ACs as treatment for infected prostheses is often considered as the gold standard in the EU and North America. However, AC is only an adjuvant treatment, and excision of infected and devascularized tissues as well as systemic antibiotic treatment managed by a multidisciplinary team remain the main factors of infection control.

A retrospective 3- to 5-year study of the reconstruction of oral function using implant-supported prostheses in patients with hypohidrotic ectodermal dysplasia.

PubMed

Zou, Duohong; Wu, Yiqun; Wang, Xu Dong; Huang, Wei; Zhang, Zhiyong; Zhang, Zhiyuan

2014-10-01

The aim of this study was to evaluate oral function rehabilitation in patients with hypohidrotic ectodermal dysplasia (HED) using implant-supported prostheses based on bone augmentation. From September 2005 and March 2009, 25 HED patients were chosen for clinical data analysis in this study. The criteria for patient selection included the following: the display of clinical features of HED, the number of congenitally missing teeth (>5), the patient age (>16 years), the patient's willingness, and the patient's tolerance for bone graft surgery and implant placement. Follow-up evaluations were initiated from the time of implant prosthetic placement and scheduled annually for 3-5 years. The effects of oral function reconstruction were assessed based on the cumulative survival and success rates of implants, the health of the peri-implant area, and the degree of patient satisfaction. Twenty-five HED patients received 169 conventional implants and 10 zygomatic implants (179 total implants). During 3-5 years of post-loading evaluations, 5 of the 179 implants failed and 3 implants were removed. The 3-year success and cumulative survival rates were 97.2% and 98.3%, respectively. Furthermore, periodontal probing and radiographic assessments showed that the 3-year incidence of peri-implantitis was 4.5%. Finally, HED patients expressed high degrees of satisfaction with their facial contours, masticatory function, pronunciation ability, and comfort with the implant-supported prostheses. The results of this 3- to 5-year retrospective study indicate that the oral function of HED patients can be effectively reconstructed using bone augmentation and implant-supported prostheses; however, longer term results are warranted in the future.

Prosthetic joint infection caused by Pasteurella multocida: a case series and review of literature.

PubMed

Honnorat, Estelle; Seng, Piseth; Savini, Hélène; Pinelli, Pierre-Olivier; Simon, Fabrice; Stein, Andreas

2016-08-20

Pasteurella multocida is a well-recognized zoonotic agent following dog or cat bites or scratches. Nevertheless, prosthetic joint infection caused by P. multocida are rarely reported. We report here a series of six cases of prosthetic joint infection caused by P. multocida managed at a referral centre for the treatment of bone and joint infection in southern France. We also reviewed the 26 cases reported in literature. The mean age of our cases was 74 years [±8.2, range 63-85]. In majority of our cases (5 cases) were associated with knee prostheses and one case with a hip prosthesis. Most of cases occurred after cat or dog scratches or licks or contact. Diagnoses of prosthetic joint infection caused by P. multocida were made by positive cultures of surgical biopsies or needle aspiration. Mean time delay between prosthetic joint implantation and infection onset was 7.6 years (±5.12 years, range 2-17). Local inflammation, which occurred in all six cases, was the most frequent clinical symptom, followed by pain in five cases, fever and swollen joints in four cases, and a fistula with purulent discharge inside the wound in two cases. The mean time of antibiotic therapy was 8 months. Surgical treatment with prosthesis removal was performed in three cases. Six of our cases were in remission without apparent relapse at 3 years after end of treatment. Prosthetic joint infections caused by P. multocida usually occur after animal scratches or bites, but can occasionally occur after a short animal lick. These infections are usually resulting from a contiguous infection and localized in the knee. An early antibiotic therapy after surgical debridement could avoid prosthetic withdrawal, notably in elderly patients. Patients with prosthetic joints should be warned that animals are potential sources of serious infection and urgent medical advice should be sought if they are bitten or scratched.

In vitro biomechanical comparison after fixed- and mobile-core artificial cervical disc replacement versus fusion

PubMed Central

Lou, Jigang; Li, Yuanchao; Wang, Beiyu; Meng, Yang; Wu, Tingkui; Liu, Hao

2017-01-01

Abstract In vitro biomechanical analysis after cervical disc replacement (CDR) with a novel artificial disc prosthesis (mobile core) was conducted and compared with the intact model, simulated fusion, and CDR with a fixed-core prosthesis. The purpose of this experimental study was to analyze the biomechanical changes after CDR with a novel prosthesis and the differences between fixed- and mobile-core prostheses. Six human cadaveric C2–C7 specimens were biomechanically tested sequentially in 4 different spinal models: intact specimens, simulated fusion, CDR with a fixed-core prosthesis (Discover, DePuy), and CDR with a mobile-core prosthesis (Pretic-I, Trauson). Moments up to 2 Nm with a 75 N follower load were applied in flexion–extension, left and right lateral bending, and left and right axial rotation. The total range of motion (ROM), segmental ROM, and adjacent intradiscal pressure (IDP) were calculated and analyzed in 4 different spinal models, as well as the differences between 2 disc prostheses. Compared with the intact specimens, the total ROM, segmental ROM, and IDP at the adjacent segments showed no significant difference after arthroplasty. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment (C5/6) and total ROM than CDR with a fixed-core prosthesis (P > .05). Besides, the difference in IDP at C4/5 after CDR with 2 prostheses was without statistical significance in all the directions of motion. However, the IDP at C6/7 after CDR with a mobile-core prosthesis was lower than CDR with a fixed-core prosthesis in flexion, extension, and lateral bending, with significant difference (P < .05), but not under axial rotation. CDR with a novel prosthesis was effective to maintain the ROM at the target segment and did not affect the ROM and IDP at the adjacent segments. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment and total ROM, but lower IDP at the inferior adjacent segment than CDR with a fixed-core prosthesis. PMID:29019902

Clinical Outcomes in Men and Women following Total Knee Arthroplasty with a High-Flex Knee: No Clinical Effect of Gender.

PubMed

Nassif, Jeffrey M; Pietrzak, William S

2015-01-01

While it is generally recognized that anatomical differences exist between the male and female knee, the literature generally refutes the clinical need for gender-specific total knee prostheses. It has been found that standard, unisex knees perform as well, or better, in women than men. Recently, high-flex knees have become available that mechanically accommodate increased flexion yet no studies have directly compared the outcomes of these devices in men and women to see if gender-based differences exist. We retrospectively compared the performance of the high-flex Vanguard knee (Biomet, Warsaw, IN) in 716 male and 1,069 female knees. Kaplan-Meier survivorship was 98.5% at 5.6-5.7 years for both genders. After 2 years, mean improvements in Knee Society Knee and Function scores for men and women (50.9 versus 46.3; 26.5 versus 23.1) and corresponding SF-12 Mental and Physical scores (0.2 versus 2.2; 13.7 versus 12.2) were similar with differences not clinically relevant. Postoperative motion gains as a function of preoperative motion level were virtually identical in men and women. This further confirms the suitability of unisex total knee prostheses for both men and women.

Composite Materials for Maxillofacial Prostheses.

DTIC Science & Technology

1981-08-01

necessary and Identify byv block number) MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : SOFT FILLERS; ELASTOMER COMPOSITES 2,. ABSTRACT...used as fillers in the fabrication of maxillofacial prostheses. The projected systems are elastomeric-shelled, liquid-filled microcapsules . Improvements...elastomeric-shelled, liquid-filled microcapsules . Experiments continued on the interfacial polymerization process, with spherical, sealed, capsules

Morphological characterization of dental prostheses interfaces using optical coherence tomography

NASA Astrophysics Data System (ADS)

Sinescu, Cosmin; Negrutiu, Meda L.; Ionita, Ciprian; Marsavina, Liviu; Negru, Radu; Caplescu, Cristiana; Bradu, Adrian; Topala, Florin; Rominu, Roxana O.; Petrescu, Emanuela; Leretter, Marius; Rominu, Mihai; Podoleanu, Adrian G.

2010-03-01

Fixed partial prostheses as integral ceramic, polymers, metal-ceramic or metal-polymers bridges are mainly used in the frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress as well as esthetic requirements. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. Dental interfaces represent one of the most significant aspects in the strength of the dental prostheses under the masticatory load. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) to characterize the dental prostheses interfaces. The materials used were several fixed partial prostheses integral ceramic, polymers, metal-ceramic and metal-polymers bridges. It is important to produce both C-scans and B-scans of the defects in order to differentiate morphological aspects of the bridge infrastructures. The material defects observed with OCT were investigated with micro-CT in order to prove their existence and positions. In conclusion, it is important to have a non invasive method to investigate dental prostheses interfaces before the insertion of prostheses in the oral cavity.

Improvements in implant dentistry over the last decade: comparison of survival and complication rates in older and newer publications.

PubMed

Pjetursson, Bjarni E; Asgeirsson, Asgeir G; Zwahlen, Marcel; Sailer, Irena

2014-01-01

The objective of this systematic review was to assess and compare the survival and complication rates of implant-supported prostheses reported in studies published in the year 2000 and before, to those reported in studies published after the year 2000. Three electronic searches complemented by manual searching were conducted to identify 139 prospective and retrospective studies on implant-supported prostheses. The included studies were divided in two groups: a group of 31 older studies published in the year 2000 or before, and a group of 108 newer studies published after the year 2000. Survival and complication rates were calculated using Poisson regression models, and multivariable robust Poisson regression was used to formally compare the outcomes of older and newer studies. The 5-year survival rate of implant-supported prostheses was significantly increased in newer studies compared with older studies. The overall survival rate increased from 93.5% to 97.1%. The survival rate for cemented prostheses increased from 95.2% to 97.9%; for screw-retained reconstruction, from 77.6% to 96.8%; for implant-supported single crowns, from 92.6% to 97.2%; and for implant-supported fixed dental prostheses (FDPs), from 93.5% to 96.4%. The incidence of esthetic complications decreased in more recent studies compared with older ones, but the incidence of biologic complications was similar. The results for technical complications were inconsistent. There was a significant reduction in abutment or screw loosening by implant-supported FDPs. On the other hand, the total number of technical complications and the incidence of fracture of the veneering material was significantly increased in the newer studies. To explain the increased rate of complications, minor complications are probably reported in more detail in the newer publications. The results of the present systematic review demonstrated a positive learning curve in implant dentistry, represented in higher survival rates and lower complication rates reported in more recent clinical studies. The incidence of esthetic, biologic, and technical complications, however, is still high. Hence, it is important to identify these complications and their etiology to make implant treatment even more predictable in the future.

Bone preserving level of osteotomy in short-stem total hip arthroplasty does not influence stress shielding dimensions - a comparing finite elements analysis.

PubMed

Burchard, Rene; Braas, Sabrina; Soost, Christian; Graw, Jan Adriaan; Schmitt, Jan

2017-08-07

The main objective of every new development in total hip arthroplasty (THA) is the longest possible survival of the implant. Periprosthetic stress shielding is a scientifically proven phenomenon which leads to inadvertent bone loss. So far, many studies have analysed whether implanting different hip stem prostheses result in significant preservation of bone stock. The aim of this preclinical study was to investigate design-depended differences of the stress shielding effect after implantation of a selection of short-stem THA-prostheses that are currently available. Based on computerised tomography (CT), a finite elements (FE) model was generated and a virtual THA was performed with different stem designs of the implant. Stems were chosen by osteotomy level at the femoral neck (collum, partial collum, trochanter sparing, trochanter harming). Analyses were performed with previously validated FE models to identify changes in the strain energy density (SED). In the trochanteric region, only the collum-type stem demonstrated a biomechanical behaviour similar to the native femur. In contrast, no difference in biomechanical behaviour was found between partial collum, trochanter harming and trochanter sparing models. All of the short stem-prostheses showed lower stress-shielding than a standard stem. Based on the results of this study, we cannot confirm that the design of current short stem THA-implants leads to a different stress shielding effect with regard to the level of osteotomy. Somehow unexpected, we found a bone stock protection in metadiaphyseal bone by simulating a more distal approach for osteotomy. Further clinical and biomechanical research including long-term results is needed to understand the influence of short-stem THA on bone remodelling and to find the optimal stem-design for a reduction of the stress shielding effect.

Disintegration of porous polyethylene prostheses.

PubMed

Kerr, A G; Riley, D N

1999-06-01

A Plastipore (porous polyethylene) Total Ossicular Replacement Prosthesis gave an excellent initial hearing result which was maintained for 14 years. Hearing then began to deteriorate and revision surgery showed disintegration of the prosthesis and a defect in the stapes footplate. Histological examination confirmed previous findings in porous polyethylene with multinucleated foreign body giant cells and breakdown of the material.

In vivo kinematics of the salto total ankle prosthesis.

PubMed

Leszko, Filip; Komistek, Richard D; Mahfouz, Mohamed R; Ratron, Yves-Alain; Judet, Thierry; Bonnin, Michel; Colombier, Jean-Alain; Lin, Sheldon S

2008-11-01

Recent technological advancements in total ankle arthroplasty (TAA) have included the introduction of the mobile bearing concept. This bearing has several advantages, but researchers have questioned whether or not increased mobility sacrifices joint stability or durability of the implant. The present study evaluated the kinematics of this type of prosthesis implanted in patients. Fluoroscopy and 3D-to-2D registration techniques were used to determine the in vivo kinematics for 20 TAA subjects performing two activities: gait and step-up. The motion of the prostheses was described in terms of clinical rotations and as rotation about the helical (screw) axis. Then, the anterior-posterior translation and axial rotation of the mobile bearing insert were determined. Among the clinical rotations, the dorsi-/plantarflexion was the most dominant, revealing the greatest pattern change and the largest magnitude. During gait, the orientation of the prosthetic components changed smoothly from plantarflexion to dorsiflexion. The average range of this motion was 9.2 degrees. For step-up activity, the range was 8.0 degrees. However, between 33% and 66% of stance phase, the talar component's orientation changed from dorsiflexion to plantarflexion. The average absolute range of anterior-posterior translation of the mobile bearing insert was 1.5 mm and 2.3 mm for gait and step-up, respectively. These measured translations were relatively small and may suggest that the rotational portion of the motion was more dominant than translational and provided sufficient mobility.

Characterizing the Mechanical Properties of Running-Specific Prostheses

PubMed Central

Beck, Owen N.; Taboga, Paolo; Grabowski, Alena M.

2016-01-01

The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10°-25°) compared to neutral (0°) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness. PMID:27973573

Revision Rates after Primary Hip and Knee Replacement in England between 2003 and 2006

PubMed Central

Sibanda, Nokuthaba; Copley, Lynn P; Lewsey, Jim D; Borroff, Mick; Gregg, Paul; MacGregor, Alex J; Pickford, Martin; Porter, Martyn; Tucker, Keith; van der Meulen, Jan H

2008-01-01

Background Hip and knee replacement are some of the most frequently performed surgical procedures in the world. Resurfacing of the hip and unicondylar knee replacement are increasingly being used. There is relatively little evidence on their performance. To study performance of joint replacement in England, we investigated revision rates in the first 3 y after hip or knee replacement according to prosthesis type. Methods and Findings We linked records of the National Joint Registry for England and Wales and the Hospital Episode Statistics for patients with a primary hip or knee replacement in the National Health Service in England between April 2003 and September 2006. Hospital Episode Statistics records of succeeding admissions were used to identify revisions for any reason. 76,576 patients with a primary hip replacement and 80,697 with a primary knee replacement were included (51% of all primary hip and knee replacements done in the English National Health Service). In hip patients, 3-y revision rates were 0.9% (95% confidence interval [CI] 0.8%–1.1%) with cemented, 2.0% (1.7%–2.3%) with cementless, 1.5% (1.1%–2.0% CI) with “hybrid” prostheses, and 2.6% (2.1%–3.1%) with hip resurfacing (p < 0.0001). Revision rates after hip resurfacing were increased especially in women. In knee patients, 3-y revision rates were 1.4% (1.2%–1.5% CI) with cemented, 1.5% (1.1%–2.1% CI) with cementless, and 2.8% (1.8%–4.5% CI) with unicondylar prostheses (p < 0.0001). Revision rates after knee replacement strongly decreased with age. Interpretation Overall, about one in 75 patients needed a revision of their prosthesis within 3 y. On the basis of our data, consideration should be given to using hip resurfacing only in male patients and unicondylar knee replacement only in elderly patients. PMID:18767900

Rapid prototyping--when virtual meets reality.

PubMed

Beguma, Zubeda; Chhedat, Pratik

2014-01-01

Rapid prototyping (RP) describes the customized production of solid models using 3D computer data. Over the past decade, advances in RP have continued to evolve, resulting in the development of new techniques that have been applied to the fabrication of various prostheses. RP fabrication technologies include stereolithography (SLA), fused deposition modeling (FDM), computer numerical controlled (CNC) milling, and, more recently, selective laser sintering (SLS). The applications of RP techniques for dentistry include wax pattern fabrication for dental prostheses, dental (facial) prostheses mold (shell) fabrication, and removable dental prostheses framework fabrication. In the past, a physical plastic shape of the removable partial denture (RPD) framework was produced using an RP machine, and then used as a sacrificial pattern. Yet with the advent of the selective laser melting (SLM) technique, RPD metal frameworks can be directly fabricated, thereby omitting the casting stage. This new approach can also generate the wax pattern for facial prostheses directly, thereby reducing labor-intensive laboratory procedures. Many people stand to benefit from these new RP techniques for producing various forms of dental prostheses, which in the near future could transform traditional prosthodontic practices.

[Effect of CO2 laser on prostheses used in middle ear surgery].

PubMed

Szymański, Marcin

2005-01-01

The use of CO2 laser is advocated in primary and revision stapes surgery. The aim of the study was to assess the effect of CO2 laser on stapes prostheses. CO2 laser was applied on several types of stapes prostheses and PORPs, with power settings suggested by the manufacturer (continuous wave, 2 W and 6 W; 0,05 s). Application of the laser on stainless steel or titanium prosthesis did not exert any effect on the structure of the prosthesis. The use of the laser on the Teflon piston caused superficial burning with power 2 W, and melting and holes in the piston with power settings at 6W. Similar plastipore prostheses were melting. Hydroxyapatite PORP shattered after application of the laser energy. Teflon and hydroxyapatite prostheses are easily damaged by the laser energy, therefore applying a laser on them should be avoided. CO2 laser can be used on stainless steel and titanium prostheses without risk of damaging them. However the possibility of transmission of heat to the vestibule has to be taken into consideration.

Ankylosis of temporomandibular joints after mandibular distraction osteogenesis in patients with Nager syndrome: Report of two cases and literature review.

PubMed

Wu, Cheng Chun; Sakahara, Daisuke; Imai, Keisuke

2017-10-01

Nager syndrome, also known as Nager acrofacial dysostosis, was first described by Nager and de Reynier in 1948. The patients commonly present with micrognathia, and a preventive tracheostomy is necessary when there are symptoms of upper airway obstruction. Mandibular distraction osteogenesis is considered as an effective procedure, which not only improves micrognathia but also minimizes the chances of tracheostomy. However, mandibular distraction osteogenesis has some complications such as relapse, teeth injury, infection, and injury of the temporomandibular joints (TMJs). In this study, the author reported two patients with Nager syndrome who suffered from ankylosis of TMJs after mandibular distraction osteogenesis. In addition, a comprehensive literature review of post-distraction ankylosis of TMJs in patients with Nager syndrome was performed. Few studies demonstrated the condition of TMJs after mandibular distraction osteogenesis, and three studies were identified from the review. One study reported ankylosis of bilateral coronoid processes, in which coronoidectomies were necessary. Another study reported the use of prostheses to replace the ankylosed joints in a patient who had undergone many surgeries of the joints, such as gap arthroplasties, reconstructions with costochondral grafts, etc. One other study raised the concept of unloading the condyles during the mandibular distraction to prevent subsequent ankylosis. It seems that multiple factors are related to the ankylosis of TMJs after mandibular distraction osteogenesis in patients with Nager syndrome. Prevention of post-distraction ankylosis of the joints is important because the treatment is difficult and not always effective. We should conduct more studies about protection of the joints during mandibular distraction in the future. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Effect of static foot posture on the dynamic stiffness of foot joints during walking.

PubMed

Sanchis-Sales, E; Sancho-Bru, J L; Roda-Sales, A; Pascual-Huerta, J

2018-05-01

The static foot posture has been related to the development of lower limb injuries. This study aimed to investigate the dynamic stiffness of foot joints during gait in the sagittal plane to understand the role of the static foot posture in the development of injuries. Seventy healthy adult male subjects with different static postures, assessed by the Foot Posture Index (FPI) (30 normal, 20 highly pronated and 20 highly supinated), were recruited. Kinematic and kinetic data were recorded using an optical motion capture system and a pressure platform, and dynamic stiffness at the different stages of the stance was calculated from the slopes of the linear regression on the flexion moment-angle curves. The effect of foot type on dynamic stiffness and on ranges of motion and moments was analysed using ANOVAs and post-hoc tests, and linear correlation between dynamic stiffness and FPI was also tested. Highly pronated feet showed a significantly smaller range of motion at the ankle and metatarsophalangeal joints and also a larger range of moments at the metatarsophalangeal joint than highly supinated feet. Dynamic stiffness during propulsion was significantly greater at all foot joints for highly pronated feet, with positive significant correlations with the squared FPI. Highly supinated feet showed greater dynamic stiffness than normal feet, although to a lesser extent. Highly pronated feet during normal gait experienced the greatest decrease in the dorsiflexor moments during propulsion, normal feet being the most balanced regarding work generated and absorbed. Extreme static foot postures show greater dynamic stiffness during propulsion and greater absorbed work, which increases the risk of developing injuries. The data presented may be used when designing orthotics or prostheses, and also when planning surgery that modifies joint stiffness. Copyright © 2018 Elsevier B.V. All rights reserved.

Fiber-reinforced composite fixed dental prostheses: two clinical reports.

PubMed

Zarow, Maciej; Paisley, Carl Stuart; Krupinski, Jerzy; Brunton, Paul Anthony

2010-06-01

Various options are available in clinical practice for the replacement of a single missing tooth, ranging from conventional fixed and removable dental prostheses to a single implant-supported crown. There are situations in which a semipermanent fixed dental prosthesis may be desirable, particularly for patients who have completed orthodontic treatment but are too young to embark on implant therapy. Following advances in fiber-reinforcement technology, fiber-reinforced composite resin (FRC) now represents a lower-cost alternative to traditional metal-ceramic for the construction of resin-bonded prostheses. Two case reports illustrate the use of FRC prostheses as fixed semipermanent_restorations.

Antibiotic prophylaxis is not indicated prior to dental procedures for prevention of periprosthetic joint infections.

PubMed

Rademacher, Willem M H; Walenkamp, Geert H I M; Moojen, Dirk Jan F; Hendriks, Johannes G E; Goedendorp, Theo A; Rozema, Frederik R

2017-10-01

Background and purpose - To minimize the risk of hematogenous periprosthetic joint infection (HPJI), international and Dutch guidelines recommended antibiotic prophylaxis prior to dental procedures. Unclear definitions and contradictory recommendations in these guidelines have led to unnecessary antibiotic prescriptions. To formulate new guidelines, a joint committee of the Dutch Orthopaedic and Dental Societies conducted a systematic literature review to answer the following question: can antibiotic prophylaxis be recommended for patients (with joint prostheses) undergoing dental procedures in order to prevent dental HPJI? Methods - The Medline, Embase, and Cochrane databases were searched for randomized controlled trials (RCTs), reviews, and observational studies up to July 2015. Studies were included if they involved patients with joint implants undergoing dental procedures, and either considered HPJI as an outcome measure or described a correlation between HPJI and prophylactic antibiotics. A guideline was formulated using the GRADE method and AGREE II guidelines. Results - 9 studies were included in this systematic review. All were rated "very low quality of evidence". Additional literature was therefore consulted to address clinical questions that provide further insight into pathophysiology and risk factors. The 9 studies did not provide evidence that use of antibiotic prophylaxis reduces the incidence of dental HPJI, and the additional literature supported the conclusion that antibiotic prophylaxis should be discouraged in dental procedures. Interpretation - Prophylactic antibiotics in order to prevent dental HPJI should not be prescribed to patients with a normal or an impaired immune system function. Patients are recommended to maintain good oral hygiene and visit the dentist regularly.

Posterior stabilized versus cruciate retaining total knee arthroplasty designs: conformity affects the performance reliability of the design over the patient population.

PubMed

Ardestani, Marzieh M; Moazen, Mehran; Maniei, Ehsan; Jin, Zhongmin

2015-04-01

Commercially available fixed bearing knee prostheses are mainly divided into two groups: posterior stabilized (PS) versus cruciate retaining (CR). Despite the widespread comparative studies, the debate continues regarding the superiority of one type over the other. This study used a combined finite element (FE) simulation and principal component analysis (PCA) to evaluate "reliability" and "sensitivity" of two PS designs versus two CR designs over a patient population. Four fixed bearing implants were chosen: PFC (DePuy), PFC Sigma (DePuy), NexGen (Zimmer) and Genesis II (Smith & Nephew). Using PCA, a large probabilistic knee joint motion and loading database was generated based on the available experimental data from literature. The probabilistic knee joint data were applied to each implant in a FE simulation to calculate the potential envelopes of kinematics (i.e. anterior-posterior [AP] displacement and internal-external [IE] rotation) and contact mechanics. The performance envelopes were considered as an indicator of performance reliability. For each implant, PCA was used to highlight how much the implant performance was influenced by changes in each input parameter (sensitivity). Results showed that (1) conformity directly affected the reliability of the knee implant over a patient population such that lesser conformity designs (PS or CR), had higher kinematic variability and were more influenced by AP force and IE torque, (2) contact reliability did not differ noticeably among different designs and (3) CR or PS designs affected the relative rank of critical factors that influenced the reliability of each design. Such investigations enlighten the underlying biomechanics of various implant designs and can be utilized to estimate the potential performance of an implant design over a patient population. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

A prospective 24 months follow-up of a three component press-fit prosthesis for hallux rigidus.

PubMed

Wassink, S; Burger, B J; Saragas, N P; Asunción Márquez, J; Trtik, L; Harlaar, J

2017-09-01

The aim of this study was to evaluate the results following total first metatarsophalangeal (FMTP) joint replacement arthroplasty using a modular three component press fit prosthesis at two year follow up. All patient data was collected in a prospective way in four study centres. Both preoperative and postoperative evaluation consisted of an assessment using the AOFAS-HMI score, visual analogue scale for pain, evaluation of the range of motion and patient satisfaction scores. Postoperative X-rays were reviewed for loosening and radiolucency up to two years. Fifty-five feet were available for analysis at 24 months. Two implants were removed during the study. Six more feet had additional surgery due to stiffness or malalignment. Postoperative AOFAS-HMI scores improved significantly by 32.4 points at two year follow-up (p<0.001). The visual analogue scale for pain improved significantly from 6.8 (std 1,6) preoperatively to 1.6 (std 1,9) postoperatively (p<0.0001). Mean dorsiflexion improved from 12.6 (std 10,1) degrees preoperatively to 31.2 (std 16,8) degrees postoperatively. Eighty-seven percent of patients were moderately to well satisfied with the end result. Eighteen prostheses showed radiolucency at 24 months. Implantation of a Metis ® modular three component press fit prosthesis for the metatarsophalangeal joint in hallux rigidus shows significant improvement in AOFAS-HMI scores and a decrease in pain. Concerns remain with regard to early reoperation rate (14.5%) and long term survival of the implant. Future studies will have to address these aspects. Copyright © 2016 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Use of an absorbable membrane to position biologically inductive materials in the periprosthetic space of cemented joints.

PubMed

DiResta, Gene R; Brown, Holly; Aiken, Sean; Doty, Steven; Schneider, Robert; Wright, Timothy; Healey, John H

2006-01-01

A device is presented that positions ultrahigh molecular weight polyethylene (UHMWPE) debris against periprosthetic bone surfaces. This can facilitate the study of aseptic loosening associated with cemented joint prostheses by speeding the appearance of this debris within the periprosthetic space. The device, composed of a 100 microm thick bioabsorbable membrane impregnated with 1.4 x 10(9) sub-micron particles of UHMWPE debris, is positioned on the endosteum of the bone prior to the insertion of the cemented orthopedic implant. An in vitro pullout study and an in vivo canine pilot study were performed to investigate its potential to accelerate "time to aseptic loosening" of cemented prosthetic joints. Pullout studies characterized the influence of the membrane on initial implant fixation. The tensile stresses (mean+/-std.dev.) required to withdraw a prosthesis cemented into canine femurs with and without the membrane were 1.15+/-0.3 and 1.54+/-0.01 MPa, respectively; these findings were not significantly different (p > 0.4). The in vivo pilot study, involving five dogs, was performed to evaluate the efficacy of the debris to accelerate loosening in a canine cemented hip arthroplasty. Aseptic loosening and lameness occurred within 12 months, quicker than the 30 months reported in a retrospective clinical review of canine hip arthroplasty.

A New Powered Lower Limb Prosthesis Control Framework Based on Adaptive Dynamic Programming.

PubMed

Wen, Yue; Si, Jennie; Gao, Xiang; Huang, Stephanie; Huang, He Helen

2017-09-01

This brief presents a novel application of adaptive dynamic programming (ADP) for optimal adaptive control of powered lower limb prostheses, a type of wearable robots to assist the motor function of the limb amputees. Current control of these robotic devices typically relies on finite state impedance control (FS-IC), which lacks adaptability to the user's physical condition. As a result, joint impedance settings are often customized manually and heuristically in clinics, which greatly hinder the wide use of these advanced medical devices. This simulation study aimed at demonstrating the feasibility of ADP for automatic tuning of the twelve knee joint impedance parameters during a complete gait cycle to achieve balanced walking. Given that the accurate models of human walking dynamics are difficult to obtain, the model-free ADP control algorithms were considered. First, direct heuristic dynamic programming (dHDP) was applied to the control problem, and its performance was evaluated on OpenSim, an often-used dynamic walking simulator. For the comparison purposes, we selected another established ADP algorithm, the neural fitted Q with continuous action (NFQCA). In both cases, the ADP controllers learned to control the right knee joint and achieved balanced walking, but dHDP outperformed NFQCA in this application during a 200 gait cycle-based testing.

Finite element analysis of a condylar support prosthesis to replace the temporomandibular joint.

PubMed

Abel, Eric W; Hilgers, André; McLoughlin, Philip M

2015-04-01

This paper presents a finite element study of a temporomandibular joint (TMJ) prosthesis in which the mandibular component sits on the condyle after removal of only the diseased articular surface and minimal amount of condylar bone. The condylar support prosthesis (CSP) is customised to fit the patient and allows a large part of the joint force to be transmitted through the condyle to the ramus, rather than relying only on transfer of the load by the screws that fix the prosthesis to the ramus. The 3-dimensional structural finite element analysis compared a design of CSP with a standard commercial prosthesis and one that was modified to fit the ramus, to relate the findings to the different designs and geometrical features. The models simulated an incisal bite under high loading. In the CSP and in its fixation screws, the stresses were much lower than those in the other 2 prostheses and the bone strains were at physiological levels. The CSP gives a more physiological form of load transfer than is possible without the condylar contact, and considerably reduces the amount of strain on the bone around the screws. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Composite Materials for Maxillofacial Prostheses.

DTIC Science & Technology

1979-08-01

block number) MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS; MICROCAPSULES ; SOFT FILLERS; ELASTuMER COMPOSITES 20,_ ABSTRACT ’Continue on reverse side...approaches were pursued toward making such microcapsules . One approach involves coaxial extrusion of a catalyzed elastomer precursor and core liquid into a...fabrication of maxillofacial prostheses. The projected composite systems are elastomeric-shelled, liquid-filled microcapsules . Two experimental approaches were

/sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip prostheses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, P.E.; Mall, J.C.; Hoffer, P.B.

1979-12-01

A retrospective study was performed to determine the accuracy of /sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip arthroplasty for loosening and/or infection. Using focally increased activity at the tip of the femoral component or in the region of the acetabular component as a criterion, the examination was 77% specific and 100% sensitive for loosening and/or infection. A possible explanation for the increased uptake at the tip of the femoral component and the role of this examination in the management of a painful total hip prosthesis are discussed.

Identification of overlengthening after replacement of the radial head with a bipolar prosthesis.

PubMed

Wegmann, K; Lamsfuss, J; Ries, C; Neiss, W F; Franklin, J; Müller, L P; Burkhart, K J

2015-12-01

Overlengthening of the radial column leads to insufficient functionality and increased capitellar wear. Methods to detect or prevent overlengthening have been described for monopolar prostheses. The aim of this study was to evaluate whether one such method described by Athwal et al. is also applicable for a bipolar prosthesis. The radial heads of six fresh frozen upper extremities were resected. A bipolar radial head prosthesis was implanted in each, and the effects of sequential overlengthening on the alignment of the radiocapitellar and ulnohumeral joint line were recorded by fluoroscopic images. Digital image analysis and estimation of overlengthening followed according to the method described by Athwal et al. Statistical analysis of the estimated and actual differences between the native state and bipolar replacement of the radial head with stepwise overlengthening of 1.5, 3, 4.5, and 6 mm showed a specificity of 86 % but consistently underestimated the amount of overlengthening with a sensitivity of only 61 %. The method described by Athwal et al. for the identification of overlengthening by a monopolar prosthesis was not found to be reliable for ruling out or quantifying overlengthening of the tested bipolar prosthesis. However, the use of the method to detect (rule in) overlengthening may be acceptable in certain circumstances. A reliable method for postoperative quantification of overlengthening by bipolar prostheses has still to be found.

The Effects of the Inertial Properties of Above-Knee Prostheses on Optimal Stiffness, Damping, and Engagement Parameters of Passive Prosthetic Knees.

PubMed

Narang, Yashraj S; Murthy Arelekatti, V N; Winter, Amos G

2016-12-01

Our research aims to design low-cost, high-performance, passive prosthetic knees for developing countries. In this study, we determine optimal stiffness, damping, and engagement parameters for a low-cost, passive prosthetic knee that consists of simple mechanical elements and may enable users to walk with the normative kinematics of able-bodied humans. Knee joint power was analyzed to divide gait into energy-based phases and select mechanical components for each phase. The behavior of each component was described with a polynomial function, and the coefficients and polynomial order of each function were optimized to reproduce the knee moments required for normative kinematics of able-bodied humans. Sensitivity of coefficients to prosthesis mass was also investigated. The knee moments required for prosthesis users to walk with able-bodied normative kinematics were accurately reproduced with a mechanical system consisting of a linear spring, two constant-friction dampers, and three clutches (R2=0.90 for a typical prosthetic leg). Alterations in upper leg, lower leg, and foot mass had a large influence on optimal coefficients, changing damping coefficients by up to 180%. Critical results are reported through parametric illustrations that can be used by designers of prostheses to select optimal components for a prosthetic knee based on the inertial properties of the amputee and his or her prosthetic leg.

A Respirometric Technique to Evaluate Velopharyngeal Function in Speakers with Cleft Palate, with and without Prostheses.

ERIC Educational Resources Information Center

Gilbert, Harvey R.; Ferrand, Carole T.

1987-01-01

Respirometric quotients (RQ), the ratio of oral air volume expended to total volume expended, were obtained from the productions of oral and nasal airflow of 10 speakers with cleft palate, with and without their prosthetic appliances, and 10 normal speakers. Cleft palate speakers without their appliances exhibited the lowest RQ values. (Author/DB)

Perioperative and rehabilitation outcome after lower-limb amputation in elderly Chinese patients in Hong Kong.

PubMed

Leung, H B; Wong, W C; Wu, F C J; Guerin, J S

2004-06-01

Major amputation of the lower limb is considered the last resort when limb salvage is impossible. The aim of this study is to determine the morbidity, mortality, and rehabilitation outcome of patients that underwent a lower-limb amputation. A retrospective cohort study was conducted among 100 elderly patients who underwent a total of 120 lower-limb amputations in a regional hospital in Hong Kong from 1996 to 2001. The mean age of the amputees was 77.9 years; 58 were female. 95% of the amputations were performed because of infection with or without vascular compromise; 55 transfemoral and 60 transtibial amputations contributed 96% of the case mix. Some 43% of patients experienced early complications and 12% required re-amputation. The early (30-day) mortality rate was 15%. Only 55% of the amputees survived after 4 years. A 44% return-home rate was achieved. However, only 11% of the amputees could walk without help from other people. Although prostheses were issued to 42% of the survivors, compliance was only 53%; 24% of the survivors lost their remaining leg within 2 years. The outcome of major lower-extremity amputation remains poor. Efforts should be made to retain these limbs. When it is proven impossible, one should strive to preserve the knee joint whenever feasible.

Design aspects and clinical performance of the thrust plate hip prosthesis.

PubMed

Jacob, H A C; Bereiter, H H; Buergi, M L

2007-01-01

The thrust plate hip prosthesis (TPP) was conceived to maintain the physiological stress distribution in the proximal femur so as to prevent bone atrophy in this region, often encountered after implantation of conventional stem-type prostheses. A thrust plate of TiAlNb is firmly fixed to the neck of the femur by means of a forged CoCrMo bolt introduced through the lateral cortex, just below the greater trochanter, and through the metaphysis. A boss that contains the bolt head rests on the lateral cortex. A proximal extension from the thrust plate terminates in the ball head of the hip joint. Bone remodelling causes the initial prestressing of the structure (primary stability) to decline, but full integration of the thrust plate with the underlying host bone affords secondary stability. A total of 102 TPPs were implanted in the Cantonal Hospital, Chur, Switzerland, from 1992 to 1999 in 84 patients. The TPP was selected particularly for patients of the younger age group (26-76). Through its ability to load the medial cortex of the proximal femur in a physiological manner, the cortical bone in this region is preserved. The mean Harris hip score is 97 points and the survival rate 98 per cent, 144 months post-operatively.

A control system for a powered prosthesis using positional and myoelectric inputs from the shoulder complex.

PubMed

Losier, Y; Englehart, K; Hudgins, B

2007-01-01

The integration of multiple input sources within a control strategy for powered upper limb prostheses could provide smoother, more intuitive multi-joint reaching movements based on the user's intended motion. The work presented in this paper presents the results of using myoelectric signals (MES) of the shoulder area in combination with the position of the shoulder as input sources to multiple linear discriminant analysis classifiers. Such an approach may provide users with control signals capable of controlling three degrees of freedom (DOF). This work is another important step in the development of hybrid systems that will enable simultaneous control of multiple degrees of freedom used for reaching tasks in a prosthetic limb.

Oral health-related quality of life in complete denture wearers depending on their socio-demographic background, prosthetic-related factors and clinical condition

PubMed Central

Perea, Carmen; Suárez-García, María J.; Del Río, Jaime; Torres-Lagares, Daniel; Montero, Javier

2013-01-01

Objectives: To investigate the differences in impact on oral health-related quality of life (OHRQoL) among complete denture wearers depending on their socio-demographic characteristics, prosthetic-related factors and oral status. Study Design: 51 patients aged 50-90 years treated, from 2005 to 2010, with at least one complete denture at the Department of Buccofacial Prostheses of the Complutense University (Madrid) were enrolled in this cross-sectional study. All of the participants answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. The additive scoring method was used. The prevalence of impacts was calculated by using the occasional threshold (OHIP-14sp score≥2). Socio-demographic and prosthetic-related variables were gathered. Patients underwent clinical examination to assess their oral condition. Descriptive probes and Chi-Square tests were run (p≤0.05). Results: The predominant participants’ profile was that of a man with a mean age of 69 years wearing complete dentures in both the maxilla and the mandible. The prevalence of impact was 23.5%, showing an average score of 19±9.8. The most affected domains were “functional limitation” and “physical pain”, followed by “physical disability”. Minor impacts were recorded for the psychological and social subscales (“psychological discomfort”, “psychological disability”, “social disability” and “handicap”). The prosthesis’ location significantly influenced the overall patient satisfaction, the lower dentures being the less comfortable. Having a complete removable denture as antagonist significantly hampered the patient satisfaction. Patients without prosthetic stomatitis and those who need repairing or changing their prostheses, recorded significantly higher OHIP-14sp total scores. Conclusions: The use of conventional complete dentures brings negative impacts in the OHRQoL of elderly patients, mainly in case of lower prostheses that required reparation or substitution, with a removable total denture as antagonist. The prosthetic stomatitis in this study was always associated to other severe illness, which may have influenced the self-perceived discomfort with the prostheses, as those patients were daily medicated with painkillers. Key words:Oral Health Impact Profile (OHIP), oral health-related quality of life (OHRQoL), patient satisfaction, complete denture, elderly patients. PMID:23385509

Three-Dimensional (3-D) Printing: A Cost-Effective Solution for Improving Global Accessibility to Prostheses.

PubMed

Silva, Kyle; Rand, Stephanie; Cancel, David; Chen, Yuxi; Kathirithamby, Rani; Stern, Michelle

2015-12-01

The lack of access to prostheses is a global problem, partially caused by the high cost associated with the current manufacturing process. Three-dimensional printing is gaining use in the medical field, and one such area is prosthetics. In addition to using cost-effective materials, this technology allows for rapid prototyping, making it an efficient solution for the development of affordable prostheses. If the rehabilitation medicine community embraces this novel technology, we can help alleviate the global disparity of access to prostheses. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

[Significance of various implantate localizations of Sparks prostheses, experimental studies in rats].

PubMed

Brieler, H S; Parwaresch, R; Thiede, A

1976-01-01

Our investigations show that Sparks prostheses after subcutaneous implantation are suitable for vascular grafting. At the end of the organization period the connective tissue becomes strong, and after the third and fourth weeks collagenous and elastic fibers can be seen. Ten weeks after s.c. implantation, collagenous fibers predominate. After this the Sparks prostheses can be used as a vascular graft. Intraperitoneal implantation, however, shows a histologically different picture with characteristic findings: only fat cells can be observed, a strong granulation tissue with elastic and collagenous fibers is not present. After intraperitoneal implantation Sparks prostheses are therefore unsuitable for vascular grafts.

Assessment of body-powered upper limb prostheses by able-bodied subjects, using the Box and Blocks Test and the Nine-Hole Peg Test.

PubMed

Haverkate, Liz; Smit, Gerwin; Plettenburg, Dick H

2016-02-01

The functional performance of currently available body-powered prostheses is unknown. The goal of this study was to objectively assess and compare the functional performance of three commonly used body-powered upper limb terminal devices. Experimental trial. A total of 21 able-bodied subjects (n = 21, age = 22 ± 2) tested three different terminal devices: TRS voluntary closing Hook Grip 2S, Otto Bock voluntary opening hand and Hosmer Model 5XA hook, using a prosthesis simulator. All subjects used each terminal device nine times in two functional tests: the Nine-Hole Peg Test and the Box and Blocks Test. Significant differences were found between the different terminal devices and their scores on the Nine-Hole Peg Test and the Box and Blocks Test. The Hosmer hook scored best in both tests. The TRS Hook Grip 2S scored second best. The Otto Bock hand showed the lowest scores. This study is a first step in the comparison of functional performances of body-powered prostheses. The data can be used as a reference value, to assess the performance of a terminal device or an amputee. The measured scores enable the comparison of the performance of a prosthesis user and his or her terminal device relative to standard scores. © The International Society for Prosthetics and Orthotics 2014.

Model-Based Estimation of Knee Stiffness

PubMed Central

Pfeifer, Serge; Vallery, Heike; Hardegger, Michael; Riener, Robert; Perreault, Eric J.

2013-01-01

During natural locomotion, the stiffness of the human knee is modulated continuously and subconsciously according to the demands of activity and terrain. Given modern actuator technology, powered transfemoral prostheses could theoretically provide a similar degree of sophistication and function. However, experimentally quantifying knee stiffness modulation during natural gait is challenging. Alternatively, joint stiffness could be estimated in a less disruptive manner using electromyography (EMG) combined with kinetic and kinematic measurements to estimate muscle force, together with models that relate muscle force to stiffness. Here we present the first step in that process, where we develop such an approach and evaluate it in isometric conditions, where experimental measurements are more feasible. Our EMG-guided modeling approach allows us to consider conditions with antagonistic muscle activation, a phenomenon commonly observed in physiological gait. Our validation shows that model-based estimates of knee joint stiffness coincide well with experimental data obtained using conventional perturbation techniques. We conclude that knee stiffness can be accurately estimated in isometric conditions without applying perturbations, which presents an important step towards our ultimate goal of quantifying knee stiffness during gait. PMID:22801482

Coplanar intensity-modulated radiotherapy class solution for patients with prostate cancer with bilateral hip prostheses with and without nodal involvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Young K., E-mail: Young.Lee@rmh.nhs.uk; McVey, Gerard P.; South, Chris P.

2013-07-01

Dose distributions for prostate radiotherapy are difficult to predict in patients with bilateral hip prostheses in situ, due to image distortions and difficulty in dose calculation. The feasibility of delivering curative doses to prostate using intensity-modulated radiotherapy (IMRT) in patients with bilateral hip prostheses was evaluated. Planning target volumes for prostate only (PTV1) and pelvic nodes (PTV2) were generated from data on 5 patients. PTV1 and PTV2 dose prescriptions were 70 Gy and 60 Gy, respectively, in 35 fractions, and an additional nodal boost of 65 Gy was added for 1 plan. Rectum, bladder, and bowel were also delineated. Beammore » angles and segments were chosen to best avoid entering through the prostheses. Dose-volume data were assessed with respect to clinical objectives. The plans achieved the required prescription doses to the PTVs. Five-field IMRT plans were adequate for patients with relatively small prostheses (head volumes<60 cm{sup 3}) but 7-field plans were required for patients with larger prostheses. Bowel and bladder doses were clinically acceptable for all patients. Rectal doses were deemed clinically acceptable, although the V{sub 50} {sub Gy} objective was not met for 4/5 patients. We describe an IMRT solution for patients with bilateral hip prostheses of varying size and shape, requiring either localized or whole pelvic radiotherapy for prostate cancer.« less

Clinical outcome and complications of thoracic and pelvic limb stump and socket prostheses.

PubMed

Phillips, Andrew; Kulendra, Elvin; Bishop, Edith; Monk, Michelle; Parsons, Kevin; House, Arthur

2017-07-20

To describe the use, quality of life, compliance, complications, and outcome of animals fitted with stump socket prostheses. Medical records of dogs fitted with a stump socket prosthesis were reviewed. Functional outcome, quality of life and complications were retrospectively assessed from an owner questionnaire. Thirteen stump socket prostheses (12 dogs) were fitted for a variety of reasons including trauma, congenital abnormalities, and neoplasia. Eight dogs had a good outcome overall and four a poor outcome. Quality of life (QOL) remained good or excellent in 10/12 dogs. Nine complications were seen in 7/12 dogs, most were manageable; surgical wound complications (n = 2) and pressures sores (n = 4) were the most frequently encountered. One dog suffered multiple complications. Thoracic and pelvic limb stump socket prostheses had a similar complication rate, however all animals with a poor outcome had a thoracic limb stump socket prosthesis; two were small breed dogs (under 10 kg) and two had bilateral thoracic limb abnormalities. Stump socket prostheses are feasible and versatile in animals. In correctly selected cases, good to excellent outcomes are possible. However, complications are frequent but often manageable. Further investigations are required into the risk factors for poor outcomes and prospective studies are required to assess changes in biomechanics, function, and QOL before and after fitting of a stump socket prosthesis. Until further evidence is available, careful consideration should be given before fitting bilateral thoracic limb stump socket prostheses or thoracic limb stump socket prostheses to small breed dogs.

In vivo testing of porous Ti-25Nb alloy serving as a femoral stem prosthesis in a rabbit model

PubMed Central

Weng, Xiaojun; Yang, Hailin; Xu, Jian; Li, Xiaosheng; Liao, Qiande; Wang, Jing

2016-01-01

The aim of the present study was to observe the performance of Ti-25Nb alloys with various porosities as femoral stem prostheses in a rabbit model, thus providing basic experimental evidence for the development of porous prostheses. The porous Ti-25Nb alloy prostheses were designed according to the morphology of the medullary cavity. These prostheses were placed into the femoral medullary cavities in 36 New Zealand white rabbits. Postoperative X-ray films, scanning electron microscopy (SEM) of the implant interface, energy-dispersive spectroscopy (EDS) analysis of the implant surface, pulling-out test and general observations were conducted. The specimens showed good biocompatibility; there was no obvious bone absorption in porous Ti-25Nb specimens with different porosities at different time points observed using X-ray films. Under SEM examination, calcium deposits were observed inside the pores and in the interface between bone and prostheses. The EDS analysis demonstrated that calcium deposits were present on the surface of the prostheses at the eight-week point postoperatively. The pulling-out test showed good bonding strength between bone and implant; after pulling out, the surface and inside the pores of the prostheses all presented bone mass. Porous Ti-25Nb alloy implants presents good biocompatibility as well as providing a biological fixation between the bone and implant. A porosity of 70% is more advantageous to the newborn bone ingrowth, combined with achieving a more solid bone-implant interface. PMID:27602063

Computerized design of speech prostheses.

PubMed

Leonard, R J

1991-08-01

The use of computerized techniques to assist in the design of palatal and/or glossal prostheses is described. Patients with oropharyngeal resection and associated speech impairment are candidates for such prostheses. Procedures discussed allow for the design of some features of the prosthesis, such as shape, location, and tests of its effect on certain speech parameters, prior to actual fabrication. Advantages and current limitations of the techniques are also discussed.

Access to Breast Prostheses via a Government-Funded Service in Victoria, Australia: Experience of Women and Service Providers

ERIC Educational Resources Information Center

Livingston, Patricia M.; White, Victoria; Roberts, Susan; Pritchard, Emma; Gibbs, Anne; Hill, David J.

2003-01-01

For many women, the only alternative to breast reconstruction following a mastectomy is to use external prostheses, which need replacing regularly at a cost of up to $395 per prosthesis. Commonwealth and state governments across Australia have responded to this need by providing subsidies to assist in the purchase of breast prostheses. However,…

Factors Associated with Sleep Quality in Maxillectomy Patients.

PubMed

Li, Na; Otomaru, Takafumi; Said, Mohamed Moustafa; Kanazaki, Ayako; Yeerken, Yesiboli; Taniguchi, Hisashi

To investigate factors affecting sleep quality in maxillectomy patients after prosthetic rehabilitation and to determine the association between defect status and sleep quality. A total of 57 patients participated in this study. Sleep quality, general health, and oral health-related quality of life (OHRQoL) were evaluated. Of the total sample, 89% had poor sleep quality. Early morning awakening and daytime sleepiness were the most common complaints. Defect status and the extent of neck dissection could affect sleep quality in these patients. Improvement of OHRQoL in patients with dentomaxillary prostheses may help improve sleep.

Prostheses for stapes surgery.

PubMed

Slattery, W H; House, J W

1995-04-01

A variety of different implants are available today for use by the otologic surgeon. All prostheses are well tolerated, and the risks of complication as a result of their implantation are comparable. The most commonly used prostheses are the wire-Teflon piston and the stainless steel bucket handle. Although the otologic surgeon has a wide variety of prostheses to choose from, most have a preference for one particular type. Results of hearing improvement following a successful stapedectomy is more a function of the surgeon's experience than of the type of prosthesis used. As James L. Sheehy, MD, so often says, "if a technique is working well for you, don't change for change's sake" (personal communication, 1994).

Improvements in survival of the uncemented Nottingham Total Shoulder prosthesis: a prospective comparative study

PubMed Central

Rosenberg, Nahum; Neumann, Lars; Modi, Amit; Mersich, Istvan J; Wallace, Angus W

2007-01-01

Background The uncemented Nottingham Total Shoulder Replacement prosthesis system (Nottingham TSR) was developed from the previous BioModular® shoulder prosthesis taking into consideration the causes of the initial implant's failure. We investigated the impact of changes in the design of Nottingham TSR prosthesis on its survivorship rate. Methods Survivorship analyses of three types of uncemented total shoulder arthroplasty prostheses (BioModular®, initial Nottingham TSR and current Nottingham TSR systems with 11, 8 and 4 year survivorship data respectively) were compared. All these prostheses were implanted for the treatment of disabling pain in the shoulder due to primary and secondary osteoarthritis or rheumatoid arthritis. Each type of the prosthesis studied was implanted in consecutive group of patients – 90 patients with BioModular® system, 103 with the initial Nottingham TSR and 34 patients with the current Nottingham TSR system. The comparison of the annual cumulative survivorship values in the compatible time range between the three groups was done according to the paired t test. Results The 8-year and 11-year survivorship rates for the initially used modified BioModular® uncemented prosthesis were relatively low (75.6% and 71.7% respectively) comparing to the reported survivorship of the conventional cemented implants. The 8-year survivorship for the uncemented Nottingham TSR prosthesis was significantly higher (81.8%), but still not in the desired range of above 90%, that is found in other cemented designs. Glenoid component loosening was the main factor of prosthesis failure in both prostheses and mainly occurred in the first 4 postoperative years. The 4-year survivorship of the currently re-designed Nottingham TSR prosthesis, with hydroxylapatite coating of the glenoid baseplate, was significantly higher, 93.1% as compared to 85.1% of the previous Nottingham TSR. Conclusion The initial Nottingham shoulder prosthesis showed significantly higher survivorship than the BioModular® uncemented prosthesis, but lower than expected. Subsequently re-designed Nottingham TSR system presented a high short term survivorship rate that encourages its ongoing use PMID:17683577

Speech assessment of patients using three types of indwelling tracheo-oesophageal voice prostheses.

PubMed

Heaton, J M; Sanderson, D; Dunsmore, I R; Parker, A J

1996-04-01

A multidisciplinary prospective study compared speech acceptability between three types of indwelling tracheo-oesophageal voice prostheses. Twenty male laryngectomees took part over five years, using 42 prostheses. Speech was assessed on a discrete scale by trained and untrained personnel. The majority scored in the mid-range for each assessor. The kappa coefficient was used to test similarity between assessors, and for all pairings agreement was significant (p < 0.05). The speech and language therapist tended to give higher scores and the patient lower. A relationship was found between patients' ages categorized by decade and the surgeon's score alone. This relationship held for Groningen high resistance and Provox prostheses individually too (p < 0.05). The untrained assessed similarly to the professionals--humans are all voice listeners. The analysis suggests surgeons find tracheo-oesophageal speech in older patients better than in younger ones; or make more allowances for the elderly. There was a trend for Provox prostheses to produce the best scores.

Optical coherence tomography and confocal microscopy investigations of dental prostheses

NASA Astrophysics Data System (ADS)

Negrutiu, Meda L.; Sinescu, Cosmin; Hughes, Michael; Bradu, Adrian; Rominu, Mihai; Todea, Carmen; Dobre, George; Podoleanu, Adrian

2008-09-01

Dental prostheses are very complex systems, heterogenous in structure, made up from various materials, with different physical properties. An essential question mark is on the physical, chemical and mechanical compatibility between these materials. They have to satisfy high stress requirements as well as esthetic challenges. The masticatory stress may induce fractures of the prostheses, which may be triggered by initial materials defects or by alterations of the technological process. The failures of dental prostheses lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of en-face optical coherence tomography as a possible non-invasive high resolution method in supplying the necessary information on the material defects of dental prostheses and microleakage at prosthetic interfaces. C-scan and B-scan OCT images as well as confocal images are acquired from a large range of samples. Gaps between the dental interfaces and material defects are clearly exposed. We conclude that OCT can successfully be used as a noninvasive analysis method.

Sport prostheses and prosthetic adaptations for the upper and lower limb amputees: an overview of peer reviewed literature.

PubMed

Bragaru, Mihai; Dekker, Rienk; Geertzen, Jan H B

2012-09-01

Sport prostheses are used by both upper- and lower-limb amputees while participating in sports and other physical activities. Although the number of these devices has increased over the past decade, no overview of the peer reviewed literature describing them has been published previously. Such an overview will allow specialists to choose appropriate prostheses based on available scientific evidence rather than on personal experience or preference. To provide an overview of the sport prostheses as they are described by the papers published in peer reviewed literature. Literature review. Four electronic databases were searched using free text and Medical Subject Headings (MESH) terms. Papers were included if they concerned a prosthesis or a prosthetic adaptation used in sports. Papers were excluded if they did not originate from peer reviewed sources, if they concerned prostheses for body parts other than the upper or lower limbs, if they concerned amputations distal to the wrist or ankle, or if they were written in a language other than English. Twenty-four papers were included in this study. The vast majority contained descriptive data and consisted of expert opinions and technical notes. Data concerning the energy efficiency, technical characteristics and special mechanical properties of prostheses or prosthetic adaptations for sports, other than running, are scarce.

Differences in myoelectric and body-powered upper-limb prostheses: Systematic literature review.

PubMed

Carey, Stephanie L; Lura, Derek J; Highsmith, M Jason

2015-01-01

The choice of a myoelectric or body-powered upper-limb prosthesis can be determined using factors including control, function, feedback, cosmesis, and rejection. Although body-powered and myoelectric control strategies offer unique functions, many prosthesis users must choose one. A systematic review was conducted to determine differences between myoelectric and body-powered prostheses to inform evidence-based clinical practice regarding prescription of these devices and training of users. A search of 9 databases identified 462 unique publications. Ultimately, 31 of them were included and 11 empirical evidence statements were developed. Conflicting evidence has been found in terms of the relative functional performance of body-powered and myoelectric prostheses. Body-powered prostheses have been shown to have advantages in durability, training time, frequency of adjustment, maintenance, and feedback; however, they could still benefit from improvements of control. Myoelectric prostheses have been shown to improve cosmesis and phantom-limb pain and are more accepted for light=intensity work. Currently, evidence is insufficient to conclude that either system provides a significant general advantage. Prosthetic selection should be based on a patient's individual needs and include personal preferences, prosthetic experience, and functional needs. This work demonstrates that there is a lack of empirical evidence regarding functional differences in upper-limb prostheses.

A retrospective study of sintered porous-surfaced dental implants in restoring the edentulous posterior mandible: up to 9 years of functioning.

PubMed

Sohn, Dong-Seok; Kim, Woo-Sung; Lee, Won-Hyuk; Jung, Heui-Seung; Shin, Im-Hee

2010-10-01

The aim of this retrospective study was to evaluate the survival rate of sintered porous-surfaced implants placed in the edentulous posterior mandibles, in relation to implant length and diameter, crown-to-implant ratio, and types of prostheses, for a maximum of 9 years of functioning (mean: 55.8 months; range: 5-108 months). The study group consisted of 43 partially edentulous patients who visited Catholic University Hospital of Daegu and 1 private dental clinic. A total of 122 sintered porous-surfaced implants--Endopore (Innova Life Sciences, Toronto, Ontario, Canada)--were placed in the edentulous posterior mandibles. Two diameter sizes (4.1 and 5.0 mm) and 4 lengths (5.0, 7.0, 9.0, and 12.0 mm) were used. All implants were restored with fixed prostheses. One hundred three implants were splinted and 21 implants were nonsplinted. Panoramic views and periapical radiographs were taken at the time of the first, postoperative, crown placement, and following checkup visits. The survival rates of the implants in relation to length, diameter, crown-to-implant ratio, and types of prostheses were investigated. Statistical data were analyzed using SPSS Win.Ver 14.0 software with the χ² test. The survival rate of the 4.1-mm-diameter implants was 100% and 91.2% for the 5.0-mm-diameter implants. The survival rates of the implants of differing diameters were found to be statistically different (P = 0.005). The survival rates of both the 5.0-mm and 7.0-mm-length implants were 100%. The survival rate of the 9.0-mm-length implants was 97.9% and for the 12.0-mm-length implants was 95.1%. There was no statistical difference in survival rates for the differing lengths of implants. Of the 103 prostheses that were splinted, the survival rate was 98.0%. The survival rate of splinted prostheses was higher than that of the nonsplinted prostheses but was found to be not statistically different. There were no failed cases when the crown-to-implant ratio was <1.0. When the crown-to-implant ratio was between 1.0 and 1.4, the failure rate of the implants was 6.7%. No failure was recorded with the ratio range of 1.5 to 2.0. Relative to the crown-to-implant ratio of 1.0, the failure rates were statistically different (P = 0.048). The cumulative survival rate of the porous-surfaced implants placed in the edentulous posterior mandibles was 97.5%. Short porous-surfaced implants showed satisfactory results after a maximum of 9 years of functioning in the edentulous posterior mandibles.

Ferromagnetic movements of middle ear implants and stapes prostheses in a 3-T magnetic resonance field.

PubMed

Fritsch, Michael H; Gutt, Jason J

2005-03-01

A 3-T magnetic resonance field may cause motion or displacement of middle ear implants not seen in studies with 1.5-T magnets. Previous publications have described the safety limitations of some otologic implants in 1.5-T magnetic resonance fields. Several company-wide recalls of implants were issued. No studies to date have been reported for otologic implants within a 3-T magnetic resonance field, nor have there been comparisons with a 1.5-T field strength. Eighteen commonly used middle ear implants and prostheses were selected. In Part 1, the prostheses were placed in Petri dishes and exposed to a 3-T magnetic resonance field. In Part 2, the particular prostheses that showed movement in Part 1 were placed into their intended use positions within temporal bone laboratory specimens and exposed to a 3-T field. Both parts were repeated in a 1.5-T field. In Part 1, three prostheses moved dramatically from their start positions when exposed to the 3-T magnetic resonance field. In Part 2, the three particular prostheses that showed movement in Part 1 showed no gross displacement or movement from their start positions within the temporal bone laboratory specimens. No implants moved in the 1.5-T field in either Part 1 or Part 2. Certain stapes prostheses move dramatically in Petri dishes in 3-T fields. When placed into temporal bone laboratory specimens, the same prostheses show no signs of movement from the surgical site in a 3-T field, and it appears that the surgical position holds the implants firmly in place. Results of published 1.5-T field studies should not be used directly for safety recommendations in a 3-T magnetic resonance. Heat, voltage induction, and vibration during exposure to the magnetic resonance fields should be considered as additional possible safety issues. Preference should be given to platinum and titanium implants in manufacturing processes and surgical selection.

In vitro evaluation of reverse torque value of abutment screw and marginal opening in a screw- and cement-retained implant fixed partial denture design.

PubMed

Kim, Seok-Gyu; Park, Jae-Uk; Jeong, Jae-Heon; Bae, Chang; Bae, Tae-Soo; Chee, Winston

2009-01-01

The purpose of this study was to evaluate the clinical efficacy of implant prostheses retained by screws and cement (SCPs) by examining the reverse torque values (RTVs) of the abutment screws and the marginal openings of the implant prostheses. Two implants (3.8 x 13 mm; Camlog Biotechnologies) were embedded in an acrylic resin block 5 mm apart. Eighteen copies of this resin specimen were fabricated and randomly divided into two groups. Two-unit implant prostheses with two different designs-purely cement-retained implant prostheses (group 1) and SCPs (group 2)-were made out of type IV gold alloy and placed on the implants. After tightening to about 30 Ncm, the preloading RTVs of the abutment screws were measured. After retightening the abutment screws or cementing the prostheses, followed by cyclic loading, the postloading RTVs of the abutment screws were examined. Also, the marginal openings of the prostheses in the two groups were measured under a stereomicroscope. These measurements were compared statistically. The postloading RTVs and their differences from the preloading RTVs of the abutment screws demonstrated no significant differences between groups (P > .05). Group 2 prostheses showed significantly smaller marginal openings than group 1 prostheses (P < .05). The forces generated when torquing the abutment screw of the SCP did not cause more loosening of the abutment screws than the purely cement-retained implant prosthesis. The SCP showed better marginal adaptation of the cement-retained part than the purely cement-retained implant prosthesis, possibly as a result of the screw-retained abutment seating the restoration. Within the limitations of this in vitro test, the SCP showed no significant difference in RTV of the abutment screw and a smaller marginal gap compared to a purely cement-retained implant prosthesis.

Immediate loading with fixed full-arch prostheses in the maxilla: Review of the literature

PubMed Central

Peñarrocha-Oltra, David; Covani, Ugo; Peñarrocha-Diago, Miguel

2014-01-01

Objectives: To critically review the evidence-based literature on immediate loading of implants with fixed full-arch prostheses in the maxilla to determine 1) currently recommended performance criteria and 2) the outcomes that can be expected with this procedure. Study Desing: Studies from 2001 to 2011 on immediate loading with fixed full-arch maxillary prostheses were reviewed. Clinical series with at least 5 patients and 12 months of follow-up were included. Case reports, studies with missing data and repeatedly published studies were excluded. In each study the following was assessed: type of study, implant type, number of patients, number of implants, number of implants per patient, use of post-extraction implants, minimum implant length and diameter, type of prosthesis, time until loading, implant survival rate, prosthesis survival rate, marginal bone loss, complications andmean follow-up time. Criteria for patient selection, implant primary stability and bone regeneration were also studied. Results: Thirteen studies were included, reporting a total of 2484 immediately loaded implants in 365 patients. Currently accepted performance criteria regarding patient and implant selection, and surgical and prosthetic procedures were deduced from the reviewed articles. Implant survival rates went from 87.5% to 100%, prosthesis survival rates from 93.8% to 100% and radiographic marginal bone loss from 0.8 mm to 1.6 mm.No intraoperative complications and only minor prosthetic complications were reported. Conclusions: The literature on immediate loading with fixed full-arch prostheses in the maxilla shows that a successful outcome can be expected if adequate criteria are used to evaluate the patient, choose the implant and perform the surgical and prosthetic treatment. Lack of homogeneity within studies limits the relevance of the conclusions that can be drawn, and more controlled randomized studies are necessary to enable comparison between the immediate and the conventional loading procedures. Key words:Immediate loading, full-arch, dental implants, loading protocols. PMID:24880445

Retrospective cohort study of the performance of the Pinnacle metal on metal (MoM) total hip replacement: a single-centre investigation in combination with the findings of a national retrieval centre

PubMed Central

Langton, David John; Sidaginamale, Raghavendra Prasad; Avery, Peter; Waller, Sue; Tank, Ghanshyabhai; Lord, James; Joyce, Thomas; Cooke, Nick; Logishetty, Raj; Nargol, Antoni Viraf Francis

2016-01-01

Objectives To determine risk factors for revision in patients implanted with a commonly used metal on metal (MoM) hip replacement. Design Retrospective cohort study in combination with a prospective national retrieval study (Northern Retrieval Registry (NRR)). Setting Combined orthopaedic unit in combination with the NRR. Participants All patients implanted with a DePuy Pinnacle MoM hip prostheses by the 2 senior authors were invited to attend for a review which included clinical examination, blood metal ion measurements, radiographs and targeted imaging. Explanted components underwent wear analysis using validated methodology and these results were compared with those obtained from the NRR. Results 489 MoM Pinnacle hips were implanted into 434 patients (243 females and 191 males). Of these, 352 patients attended the MoM recall clinics. 64 patients had died during the study period. For the purposes of survival analysis, non-attendees were assumed to have well-functioning prostheses. The mean follow-up of the cohort as a whole was 89 months. 71 hips were revised. Prosthetic survival for the whole cohort was 83.6% (79.9–87.3) at 9 years. The majority of explanted devices exhibited signs of taper junction failure. Risk factors for revision were bilateral MoM prostheses, smaller Pinnacle liners, and implantation in 2006 and later years. A significant number of devices were found to be manufactured out of their specifications. This was confirmed with analysis of the wider data set from the NRR. Conclusions This device was found to have an unacceptably high revision rate. Bilateral prostheses, those implanted into female patients and devices implanted in later years were found to be at greater risk. A significant number of explanted components were found to be manufactured with bearing diameters outside of the manufacturer's stated tolerances. Our findings highlight the clinical importance of hitherto unrecognised variations in device production. PMID:27130159

Gender differences of the morphology of the distal femur and proximal tibia in a Korean population.

PubMed

Lim, Hong-Chul; Bae, Ji-Hoon; Yoon, Ji-Yeol; Kim, Seung-Ju; Kim, Jae-Gyoon; Lee, Jae-Moon

2013-01-01

We conducted this study to determine whether the sizes of distal femurs and proximal tibiae in Korean men and women are different, and to assess suitability of the sizes of prostheses currently used in Korea. We performed morphological analysis of proximal tibia and distal femur on 115 patients (56 male, 59 female) using MRI to investigate a gender difference. Tibial mediolateral dimension (tMAP), tibial medial anteroposterior dimension (tMAP), tibial lateral anteroposterior dimension (tLAP) femoral mediolateral dimension (fML), femoral medial anteroposterior dimension (fMAP), and femoral lateral anteroposterior dimension (fLAP) were measured. The ratio of tMAP and tLAP to tML (plateau aspect ratio, tAP/tML×100%), and that of fMAP and fLAP to fML (condylar aspect ratio, fAP/fML×100%) were calculated. The measurements were compared with the similar dimensions of four total knee implants currently used. The tML and tAP lengths showed a significant gender difference (P<0.05). The plateau aspect ratio (tMAP/tML) revealed a significant difference between male (0.74±0.05) and female (0.68±0.04, P<0.05). For morphotype of distal femur, males were found to have significantly large values (P<0.05) in the parameters, except for fLAP. With regards to the ratio of the ML width to the AP length, the women showed a narrower ML width than the men. Both genders were distributed within the range of the dimensions of the prostheses currently used prostheses. Korean population revealed that women have smaller dimensions than male counterparts. In both genders, a relatively small size of prostheses matches distal femur and proximal tibia better among the implants currently used in Korea. Copyright © 2012 Elsevier B.V. All rights reserved.

Staged lengthening arthroplasty for pediatric osteosarcoma around the knee.

PubMed

Kong, Chang-Bae; Lee, Soo-Yong; Jeon, Dae-Geun

2010-06-01

Orthopaedic oncologists often must address leg-length discrepancy after resection of tumors in growing patients with osteosarcoma. There are various alternatives to address this problem. We describe a three-stage procedure: (1) temporary arthrodesis, (2) lengthening by Ilizarov apparatus, and (3) tumor prosthesis. We asked (1) to what extent are affected limbs actually lengthened; (2) how many of the patients who undergo a lengthening procedure eventually achieve joint arthroplasty; and (3) can the three-stage procedure give patients a functioning joint with equalization of limb length? We reviewed 56 patients (younger than 14 years) with osteosarcoma who had staged lengthening arthroplasty between 1991 and 2004. Thirty-five of the 56 patients (63%) underwent soft tissue lengthening, and of these 35, 28 (50% of the original group of 56) had implantation of a mobile joint. Three of the 28 prostheses were later removed owing to infection after arthroplasty. The overall average length gained was 7.8 cm (range, 4-14 cm), and 25 (71%) of the 35 patients had a mobile joint at final followup. The average Musculoskeletal Tumor Society functional score was 23.2 (range, 15-28) and limb-length discrepancy at final followup was 2.6 cm (range, 0-6.5 cm). Although most mobile joints had an acceptable ROM (average, 74.2 degrees ; range, 35 degrees -110 degrees ), extension lag was frequent. Our approach is one option for skeletally immature patients, especially in situations where an expandable prosthesis is not available. However, this technique requires multiple stages and would be inappropriate for patients who cannot accept prolonged functional deficit owing to a limited lifespan or other reasons. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Development of an above-knee prosthesis equipped with a microcomputer-controlled knee joint: first test results.

PubMed

Aeyels, B; Peeraer, L; Vander Sloten, J; Van der Perre, G

1992-05-01

The shortcomings of conventional above-knee prostheses are due to their lack of adaptive control. Implementation of a microcomputer controlling the knee joint in a passive way has been suggested to enhance the patient's gait comfort, safety and cosmesis. This approach was used in the design of a new prosthetic system for the above-knee amputee, and tested on one patient. The knee joint of a conventional, modular prosthesis was replaced by a knee joint mechanism, equipped with a controllable brake on the knee joint axis. Sensors and a microcomputer were added, keeping the system self-contained. The modularity of the design permits the use of an alternative, external, PC-based control unit, emulating the self-contained one, and offering extended data monitoring and storage facilities. For both units an operating environment was written, including sensor/actuator interfacing and the implementation of a real-time interrupt, executing the control algorithm. A double finite state approach was used in the design of the control algorithm. On a higher level, the mode identification algorithm reveals the patient's intent. Within a specific mode (lower level), the relevant mode control algorithm looks for the current phase within the gait cycle. Within a particular phase, a specific simple control action with the brake replaces normal knee muscle activity. Tests were carried out with one prosthetic patient using a basic control algorithm for level walking, allowing controlled knee flexion during stance phase. The technical feasibility of such a concept is illustrated by the test results, even though only flexion during early stance phase was controlled during the trials.(ABSTRACT TRUNCATED AT 250 WORDS)

Generation of hybrid sinograms for the recovery of kV-CT images with metal artifacts for helical tomotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Hosang; Park, Dahl; Kim, Wontaek

Purpose: The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients’ metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. Methods: CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuationmore » projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors’ approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors’ hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR methods. Results: The authors compared the image quality and MAR performance of the hybrid method with those of other imaging modalities and the three MAR methods, respectively. The total measured mean of the CNR (SNR) values for the nonmetal inserts was determined to be 14.3 (35.3), 15.3 (37.8), and 25.5 (64.3) for the kV, MV, and hybrid images, respectively, and the spatial resolutions of the hybrid images were similar to those of the kV images. The measured densities of the metal and nonmetal inserts in the hybrid images were in good agreement with their true densities, except in cases of extremely low densities, such as air and lung. Using the hybrid method, major streak artifacts were suitably removed and no secondary artifacts were introduced in the resultant image. In clinical trials, the authors verified that kV and MV projections were successfully combined and turned into the resultant hybrid image with high image contrast, accurate metal information, and few metal artifacts. The hybrid method also outperformed the three existing MAR methods with regard to metal information restoration and secondary artifact prevention. Conclusions: The authors have shown that the hybrid method can restore the overall image quality of kV-CT disfigured by severe metal artifacts and restore the information of metal prostheses lost due to photon starvation. The hybrid images may allow for the improved delineation of structures of interest and accurate dose calculations for radiation treatment planning for patients with metal prostheses.« less

Outcome of prosthesis matched and unmatched patella components in primary and revision total knee replacement.

PubMed

Lewis, Peter L; Gamboa, Ai E; Campbell, David G; Lorimer, Michelle

2017-10-01

Although knee replacements have specifically designed patella prostheses that correspond to the geometry of their femoral components, a patella prosthesis that is unmatched to the femoral component may occasionally be inserted. In revision total knee arthroplasty (TKA), an originally resurfaced patella may be left, but the femoral component revised to one that does not match the patella. Few studies have compared the outcome of matched and unmatched patella components in TKA. This study compared the primary or revision TKA outcome of procedures where patella components matched to their femoral counterparts were inserted, with procedures using patella and femoral components that were unmatched. Data on all primary and revision TKA procedures without a patella component or a matched or an unmatched patella component were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Revision surgery was the outcome measure. Cumulative percent revised (CPR) were calculated and Hazard ratios with p values were used to test statistical significance. In primary TKA, there were higher rates of revision where unmatched patella components were used, regardless of implant design. There was no difference in the second revision rates of unmatched versus matched patella component groups. This was evident where delayed resurfacing was carried out, and where the patella prosthesis was left alone but the femoral component was changed. All primary TKA procedures require a patella component corresponding to the femoral component if the patella is resurfaced. Conversely, revision knee arthroplasties are not affected by the use of dissimilar patella and femoral components. Copyright © 2017 Elsevier B.V. All rights reserved.

Survivorship and complications of total hip arthroplasty in patients with dwarfism.

PubMed

Modi, Ronuk M; Kheir, Michael M; Tan, Timothy L; Penny, Gregory S; Chen, Chi-Lung; Shao, Hongyi; Chen, Antonia F

2017-09-19

Total hip arthroplasty (THA) is a common procedure used to treat bony hip deformities and skeletal dysplasia in dwarfism. These surgeries are often more difficult than conventional THA as they may involve malformed joints and poor bone quality, and may require smaller prostheses. This study aims to investigate whether implant survivorship and revision rates vary among patients with and without dwarfism undergoing THA. A retrospective case-control study was performed for 102 THAs completed between 1997 and 2014 in patients under the height threshold of 147.32 cm. This cohort was matched 1:1.5 with patients of normal height with respect to age, gender, year of surgery, and Charlson comorbidities. All cases had a minimum follow-up of 1 year. A chart review was performed to identify patient and surgical characteristics, including outcomes. Radiographs were assessed for deformity, loosening, and periprosthetic fractures among other factors. The 2-, 5-, and 10-year survivorship of THA in patients with dwarfism was 92.9%, 92.9%, and 80.7%, respectively; and 94.4%, 86.4%, and 86.4% for controls, respectively (p = 0.95). The dwarfism cohort demonstrated an OR of 3.81 and 3.02 for revision for periprosthetic fractures (p = 0.11) and mechanical wear (p = 0.21), respectively. THA in patients with dwarfism achieves comparable results to a non-dwarfism population with regards to implant survivorship; however, there is a trend toward increased periprosthetic fractures and wear-related failures. Surgeons should be aware of this potentially higher risk in this population and take morphological differences into account during surgical planning and technique.

Correlating subjective and objective descriptors of ultra high molecular weight wear particles from total joint prostheses.

PubMed

McMullin, Brian T; Leung, Ming-Ying; Shanbhag, Arun S; McNulty, Donald; Mabrey, Jay D; Agrawal, C Mauli

2006-02-01

A total of 750 images of individual ultra-high molecular weight polyethylene (UHMWPE) particles isolated from periprosthetic failed hip, knee, and shoulder arthroplasties were extracted from archival scanning electron micrographs. Particle size and morphology was subsequently analyzed using computerized image analysis software utilizing five descriptors found in ASTM F1877-98, a standard for quantitative description of wear debris. An online survey application was developed to display particle images, and allowed ten respondents to classify particle morphologies according to commonly used terminology as fibers, flakes, or granules. Particles were categorized based on a simple majority of responses. All descriptors were evaluated using a one-way ANOVA and Tukey-Kramer test for all-pairs comparison among each class of particles. A logistic regression model using half of the particles included in the survey was then used to develop a mathematical scheme to predict whether a given particle should be classified as a fiber, flake, or granule based on its quantitative measurements. The validity of the model was then assessed using the other half of the survey particles and compared with human responses. Comparison of the quantitative measurements of isolated particles showed that the morphologies of each particle type classified by respondents were statistically different from one another (p<0.05). The average agreement between mathematical prediction and human respondents was 83.5% (standard error 0.16%). These data suggest that computerized descriptors can be feasibly correlated with subjective terminology, thus providing a basis for a common vocabulary for particle description which can be translated into quantitative dimensions.

Correlating subjective and objective descriptors of ultra high molecular weight wear particles from total joint prostheses

PubMed Central

McMullin, Brian T.; Leung, Ming-Ying; Shanbhag, Arun S.; McNulty, Donald; Mabrey, Jay D.; Agrawal, C. Mauli

2014-01-01

A total of 750 images of individual ultra-high molecular weight polyethylene (UHMWPE) particles isolated from periprosthetic failed hip, knee, and shoulder arthroplasties were extracted from archival scanning electron micrographs. Particle size and morphology was subsequently analyzed using computerized image analysis software utilizing five descriptors found in ASTM F1877-98, a standard for quantitative description of wear debris. An online survey application was developed to display particle images, and allowed ten respondents to classify particle morphologies according to commonly used terminology as fibers, flakes, or granules. Particles were categorized based on a simple majority of responses. All descriptors were evaluated using a one-way ANOVA and Tukey–Kramer test for all-pairs comparison among each class of particles. A logistic regression model using half of the particles included in the survey was then used to develop a mathematical scheme to predict whether a given particle should be classified as a fiber, flake, or granule based on its quantitative measurements. The validity of the model was then assessed using the other half of the survey particles and compared with human responses. Comparison of the quantitative measurements of isolated particles showed that the morphologies of each particle type classified by respondents were statistically different from one another (po0:05). The average agreement between mathematical prediction and human respondents was 83.5% (standard error 0.16%). These data suggest that computerized descriptors can be feasibly correlated with subjective terminology, thus providing a basis for a common vocabulary for particle description which can be translated into quantitative dimensions. PMID:16112725

Friction in hip prostheses.

PubMed

Hall, R M; Unsworth, A

1997-08-01

Although the reduction of frictional torques was the driving force behind the design of the Charnley prosthesis, later concerns about wear and subsequent loosening of this and other hip replacements have dominated debate within the bioengineering community. To stimulate discussion on the role of friction in loosening, a review of the frictional characteristics of different prostheses was undertaken. The use of simple laboratory screening-type machines in the frictional assessment of different material combinations is discussed together with experiments performed on single axis simulators using both conventional and experimental prostheses. In particular, recent developments in the use of soft layer components are highlighted. Further, the possible link between excessively high frictional torques and loosening is discussed in the light of current results obtained from explanted prostheses.

The use of prostheses in skeletally immature patients.

PubMed

Abudu, Adesegun; Grimer, Robert; Tillman, Roger; Carter, Simon

2006-01-01

Prosthetic reconstruction in the skeletally immature patient is challenging because of the necessity to cope with expected disruption of limb growth after resection of one or more major growth plates and the high demands placed on implants by young patients. Although prosthetic reconstruction in children is fraught with many problems, it is usually possible to obtain a good functional limb at skeletal maturity. Extendable prostheses are readily acceptable to patients and their parents. The availability of noninvasive extendable prostheses is expected to lead to fewer complications, fewer surgical interventions, and even improved function. This article reviews the indication, evolution, and clinical and functional results of extendable endoprostheses, drawing from experience in the last 30 years of using such prostheses in children.

Mobile-bearing total knee arthroplasty: a full traumatic rotation of 180°.

PubMed

Sudanese, Alessandra; Castiello, Emanuela; Affatato, Saverio

2013-06-25

From February 2008 to September 2012 we implanted 204 mobile-bearing knee prostheses in 192 patients. All the prostheses were cemented (both femoral and tibial components), and the patella was not replaced. Only one early complication of the implants (1/204 = 0.004%) occurred after a traumatic event as a full 180° rotation of the mobile-bearing polyethylene insert. A 78-year-old woman presented with swelling and severe pain at her right knee. This traumatic event was the only case among our mobile-bearing insert patients. 
The failed polyethylene inserts were retrieved and studied using a scanning electron microscope (SEM, ZEISS EVO 50 EP, Cambridge, UK) operating at 20 kV. 
Scratching and pitting were found on the UHMWPE insert perpendicular to the machining tracks for the concave surface. SEM micrographs of the insert showed burnishing on the concave surfaces and longitudinal scratches were clearly detectable and well-marked on the analyzed surfaces. 
A traumatic, fully rotating, polyethylene insert is rare and our case is the first report describing a traumatic event with a complete 180 degree rotation mobile-bearing in a total knee prosthesis. 
In the literature few reports discuss clinical outcomes after total knee arthroplasty in patients with Parkinson's disease and they cite mixed results. However, some authors suggest that posterior-stabilized and cruciate-retaining TKA should work well while others prefer cruciate-retaining, condylar constrained kinetics, or hinged devices. Although we did not implant a posterior-stabilized mobile-bearing total knee prosthesis or a constrained prosthesis, we obtained good clinical and radiological results at the 2-year followup.

Bone-preserving total hip arthroplasty in avascular necrosis of the hip-a matched-pairs analysis.

PubMed

Merschin, David; Häne, Richard; Tohidnezhad, Mersedeh; Pufe, Thomas; Drescher, Wolf

2018-07-01

Short-stem hip arthroplasty has the potential advantage of femoral bone stock preservation, especially in view of the expected revisions in the often relatively young patients. Despite short-stem hip prosthesis are increasingly used for total hip arthroplasty, there are no sufficient mid- and long-term results especially for patients with avascular femoral head osteonecrosis. The present study investigates mid-term functional results as well as the revision rate following implantation of a short-stem prosthesis. In the period 06/2005 until 12/2013, a total of 351 short-stem hip prostheses were implanted. The study included 331 complete data sets. A retrospective analysis was performed using the Oxford Hip Score. All revisions were registered. In a total of 331 prostheses, the Oxford Hip Score was "excellent" in 66.2%, "good" in 12.7%, "fair" in 13.0%, and "poor" in 8.2% with a mean follow-up of 57.4 months (SD ± 29.8; range 24-115). In 26 cases, aseptic osteonecrosis of the hip was the indication (7.9%). The Oxford Hip Score was "excellent" in 66.7%, "good" in 0.0%, "fair" in 20.8%, and "poor" in 12.5%. The cumulated five year survival rate was 96.7%. In mid-term observation, the Metha® short-stem prosthesis shows no disadvantage in functional outcome and in survival time compared to a standard hip stem. Providing a correct indication, the Metha® short stem is a valuable option in total hip arthroplasty for younger patients with avascular osteonecrosis of the femoral head. Evaluation has shown no significant differences between aseptic osteonecrosis and other indications.

Regulation of step frequency in transtibial amputee endurance athletes using a running-specific prosthesis.

PubMed

Oudenhoven, Laura M; Boes, Judith M; Hak, Laura; Faber, Gert S; Houdijk, Han

2017-01-25

Running specific prostheses (RSP) are designed to replicate the spring-like behaviour of the human leg during running, by incorporating a real physical spring in the prosthesis. Leg stiffness is an important parameter in running as it is strongly related to step frequency and running economy. To be able to select a prosthesis that contributes to the required leg stiffness of the athlete, it needs to be known to what extent the behaviour of the prosthetic leg during running is dominated by the stiffness of the prosthesis or whether it can be regulated by adaptations of the residual joints. The aim of this study was to investigate whether and how athletes with an RSP could regulate leg stiffness during distance running at different step frequencies. Seven endurance runners with an unilateral transtibial amputation performed five running trials on a treadmill at a fixed speed, while different step frequencies were imposed (preferred step frequency (PSF) and -15%, -7.5%, +7.5% and +15% of PSF). Among others, step time, ground contact time, flight time, leg stiffness and joint kinetics were measured for both legs. In the intact leg, increasing step frequency was accompanied by a decrease in both contact and flight time, while in the prosthetic leg contact time remained constant and only flight time decreased. In accordance, leg stiffness increased in the intact leg, but not in the prosthetic leg. Although a substantial contribution of the residual leg to total leg stiffness was observed, this contribution did not change considerably with changing step frequency. Amputee athletes do not seem to be able to alter prosthetic leg stiffness to regulate step frequency during running. This invariant behaviour indicates that RSP stiffness has a large effect on total leg stiffness and therefore can have an important influence on running performance. Nevertheless, since prosthetic leg stiffness was considerably lower than stiffness of the RSP, compliance of the residual leg should not be ignored when selecting RSP stiffness. Copyright © 2016 Elsevier Ltd. All rights reserved.

Frequency and Type of Prosthetic Complications Associated with Interim, Immediately Loaded Full-Arch Prostheses: A 2-Year Retrospective Chart Review.

PubMed

Drago, Carl

2016-08-01

The purpose of this report was to retrospectively evaluate implant and immediate full-arch prosthesis survival rates over a 24-month period; patients were consecutively treated with immediate occlusal loading. Dental arch, gender, and implant orientation (vertical vs. tilted) were also noted. All Brånemark System implants (Nobel Active) and interim, all-acrylic resin prostheses placed in patients following an All-on-Four™ protocol, in a single private practice were assessed by retrospective patient chart review. The amount of space provided surgically for implant restorative components and prostheses was determined from measurements of the vertical heights of the interim prostheses in the right/left anterior and posterior segments. These measurements were made in the laboratory. Interim prosthetic repairs (type, frequency, length of time from insertion) were analyzed by type, arch, gender, and implant orientation. Implant survival and insertion torque values were also measured. Inclusion criteria consisted of all Brånemark System implants placed with the All-on-Four protocol from September 1, 2011, until August 31, 2013. Specific dietary instructions were given for the first 7 days immediately postoperatively and for the weeks prior to insertion of the definitive prostheses. One hundred twenty-nine patients, comprising 191 arches (766 implants) from September 1, 2011, until August 31, 2013, were included in the study. One patient experienced implant failure yielding an overall implant survival rate (SR) of 99.5% (762 of 766). Four hundred twenty-six of 430 maxillary implants and 336 of 336 mandibular implants survived for SRs of 99.1% and 100%, respectively. Regarding implant orientation, 415 of 417 tilted implants (SR 99.5%) and 343 of 345 (CSR 95.6%) vertical implants were noted to be clinically stable. Interim, all-acrylic resin prostheses were in place for a mean of 199.2 days; mandibular prostheses were in place for an average of 195.4 days; maxillary prostheses were in place for an average of 202.0 days. Thirty four of the 191 interim prostheses (17.8%) warranted at least one repair during the treatment period. The average overall implant insertion torque value was 60.74 Ncm; mandibular torque values averaged 63.08 Ncm; maxillary torque values averaged 59.00 Ncm. The results from this study suggest that dental arch, gender, and implant orientation for implants placed and immediately restored with interim, all-acrylic resin, full-arch prostheses per the All-on-Four protocol did not have significant statistical or clinical effects on prosthetic complications of the interim prostheses or implant survival. Only one of the 129 patients experienced implant failures, indicating that the All-on-Four treatment protocol used in this study is a viable alternative to other protocols for rehabilitating edentulous patients. © 2015 by the American College of Prosthodontists.

Survival rates and bone loss after immediate loading of implants in fresh extraction sockets (single gaps). A clinical prospective study with 4 year follow-up

PubMed Central

Wojtovicz, Eduardo; España-Lopez, Antonio; Jimenez-Guerra, Alvaro; Monsalve-Guil, Loreto; Ortiz-Garcia, Ivan; Serrera-Figallo, Maria-Angeles

2018-01-01

Background The aim of this prospective study was to report the outcome of treatment with implants inserted after tooth extraction and immediately loaded. Material and Methods Fifty-six patients with single tooth loss were treated with 116 IPX Galimplant® implants with internal connections and a sandblasted, acid-etched surface. All implants were placed after tooth extraction using a flapless approach without bone regeneration, and they were then immediately loaded with cemented acrylic prostheses. After a period of three months, definitive cemented ceramic prostheses were placed. Patients were examined throughout a total of 4 years of follow-up. Marginal bone loss and survival rates were evaluated using digital periapical radiographs, taking into account clinical variables such as age, gender, smoking, history of periodontitis, etiology of extraction, placement site, diameter, and implant length. The Mann-Whitney U and Kruskal-Wallis non-parametric tests were used to compare differences between subgroups created based on the different clinical variables identified. Results Clinical results indicate an implant survival and success rate of 97.4%. Three implants were lost. Of the 116 immediate acrylic single crowns initially placed, 113 were replaced with definitive ceramic crowns after 3 months. A total of 77.8% of implants were inserted in the maxilla, while 22.2% were inserted in the mandible. No further complications were reported after the follow-up period (4 years). The mean marginal bone loss was 0.67 mm ± 0.40 mm. No differences were found among the subgroups of study patients. Conclusions This study indicates that dental implants that are inserted after tooth extraction and immediately loaded may constitute a successful and predictable alternative implant treatment. Key words:Dental implants, post-extraction implants, fresh sockets, immediate loading, immediate prostheses, implant dentistry. PMID:29476669

A 5-22-year follow-up study of stemmed alumina ceramic total elbow arthroplasties with cement fixation for patients with rheumatoid arthritis.

PubMed

Nishida, Keiichiro; Hashizume, Kenzo; Nasu, Yoshihisa; Kishimoto, Makoto; Ozaki, Toshifumi; Inoue, Hajime

2014-01-01

We determined mid to long-term results of total elbow arthroplasty (TEA) by use of unlinked elbow prostheses with solid alumina ceramic trochleae, and ceramic ulnar stems (stemmed Kyocera type I; SKC-I) for patients with rheumatoid arthritis. Fifty-four elbows of 39 patients were available for detailed clinical and radiographic review after a follow-up period of at least 5 years. The mean follow-up period was 12.6 years (range 5-22 years). Clinical condition before and after surgery was assessed by use of a modified version of the Mayo Elbow Performance Score (MEPS; 0-100 points) and a Japan Orthopaedic Association Elbow score (JOA score; 0-100 points). The radiographs were reviewed and loosening was defined as a progressive radiolucent line >1 mm wide that was completely circumferential around the prosthesis. Clinical records of post-operative events affecting the elbows were used for survival analysis of the prostheses using the Kaplan-Meier method. The average modified MEPS and JOA scores improved significantly from 39.7 ± 14.3 to 44.7 ± 9.4, respectively, pre-operatively, to 89.7 ± 15.4 and 83.1 ± 12.8, respectively, post-operatively (P < 0.0001). The functional assessment score also improved from 4.9 ± 2.8 to 8.5 ± 3.3 points (P < 0.0001). With loosening or implant revision defined as end points, the likelihood of survival of the prosthesis for up to 20 years was 92.6% (95% confidence interval (CI), 85.6-100.0) or 86.3 % (95 % CI 75.0-97.6), respectively. Satisfactory clinical results were obtained after TEA using SKC-I prostheses, which provided excellent pain relief and functional range of motion. The results of our study reveal the high reliability over a long period of the cemented SKC-I prosthesis with an alumina ceramic component.

[Treatment of periprosthetic femoral fractures after total hip arthroplasty with specially constructed retrograde hollow nails].

PubMed

Szalay, G; Meyer, C; Mika, J; Schnettler, R; Thormann, U

2014-12-01

Treatment of periprosthetic fractures by implantation of a specially constructed, retrograde hollow nail which fits over the tip of the prosthesis and becomes locked on it. Periprosthetic femoral fractures with firmly anchored prosthesis shaft after total hip arthroplasty of types B1 and C according to the Vancouver classification. Loosened prosthesis (type B2/B3) and trochanteric fractures (type A). Broken or damaged prosthesis, florid inflammation and soft tissue injuries in the operation field, contracted knee joint, advanced deformation in the knee joint and distal femur, enclosed prosthesis and general contraindications. In a supine position the periprosthetic fracture is exposed via a lateral access. For cemented prostheses the cement is removed around the tip of the prosthesis (at least 2-3 cm) and medullary cavity. Arthrotomy with flexion of the knee joint and marking of the nail entry point. Drill the medullary cavity, retrograde introduction of the nail, visually fit the nail over the tip of the prosthesis and lock the nail with the prosthesis. If necessary use additional spongiosaplasty or also placement of additional cerclages depending on fracture type and size of the defect zone. Lock the nail distally. Use intraoperative radiological imaging to control correct positioning and length of the nail. Close the wound layer by layer with placement of suction drainage devices and dressing. Partial loading for 6 weeks with a subsequent pain-adapted loading gradient until full loading is possible. If selective partial loading is not possible, a decision must be made in individual cases as to whether the intraoperative findings allow immediate full loading. From 2004 to 2011 a total of 25 periprosthetic femoral fractures in 25 patients were treated in 2 locations using specially constructed slotted hollow nails. Within the framework of a retrospective study 20 of these patients (16 female and 4 male; average age 77.2 [72-84] years) were clinically and radiologically re-examined on average 19.3 (7-31) months postoperatively. No postoperative bleeding, wound healing disorders and infections. In all patients there was a loading stable consolidation of the fracture in the correct femoral axis, length and rotation with no evidence for radiological signs of loosening of the prosthesis or dislocation of the nails. In one case there was loosening of the prosthesis which had obviously occurred during the operative procedure. After consolidation of the fracture it was necessary to exchange the prosthesis for a long shafted prosthesis. A comparable situation to the preoperative degree of mobility was found in 12 out of the 20 patients, a moderate deterioration in 5 patients, a substantial residual impairment in 2 patients and an improvement of the situation in 1 patient.

Estimation of Quasi-Stiffness of the Human Knee in the Stance Phase of Walking

PubMed Central

Shamaei, Kamran; Sawicki, Gregory S.; Dollar, Aaron M.

2013-01-01

Biomechanical data characterizing the quasi-stiffness of lower-limb joints during human locomotion is limited. Understanding joint stiffness is critical for evaluating gait function and designing devices such as prostheses and orthoses intended to emulate biological properties of human legs. The knee joint moment-angle relationship is approximately linear in the flexion and extension stages of stance, exhibiting nearly constant stiffnesses, known as the quasi-stiffnesses of each stage. Using a generalized inverse dynamics analysis approach, we identify the key independent variables needed to predict knee quasi-stiffness during walking, including gait speed, knee excursion, and subject height and weight. Then, based on the identified key variables, we used experimental walking data for 136 conditions (speeds of 0.75–2.63 m/s) across 14 subjects to obtain best fit linear regressions for a set of general models, which were further simplified for the optimal gait speed. We found R2 > 86% for the most general models of knee quasi-stiffnesses for the flexion and extension stages of stance. With only subject height and weight, we could predict knee quasi-stiffness for preferred walking speed with average error of 9% with only one outlier. These results provide a useful framework and foundation for selecting subject-specific stiffness for prosthetic and exoskeletal devices designed to emulate biological knee function during walking. PMID:23533662

Clinical and radiological mid-term results of the thrust plate prosthesis

PubMed Central

v.d. Daele, R.; Simon, U.; Goetze, C.

2009-01-01

The purpose of this study was to perform an objective clinical and radiological assessment of the thrust plate prosthesis (TPP). Fifty-three prostheses were evaluated clinically using the Harris hip score (HHS), visual analog scale (VAS), and radiographically before surgery, at the time of discharge, and postoperatively after on average of 8.09 (range 4.61–9.93) years. The average HHS significantly (p ≤ 0.05) improved from 48 (range 18–77) points to 95 (range 46–100) points. The VAS revealed significant (p ≤ 0.05) reduction of pain at rest and under load. Radiographic analysis showed a considerable potential for osteolysis under the thrust plate. Sixteen prostheses revealed signs of radiolucent zones. In general, there was a good clinical outcome with no major limitations in function. Radiographic changes under the thrust plate indicate an adaptation processes resulting from changed biomechanics. This study suggests that the TPP could be a good alternative in total hip replacement in younger patients. PMID:19184010

Custom hip prostheses by integrating CAD and casting technology

NASA Astrophysics Data System (ADS)

Silva, Pedro F.; Leal, Nuno; Neto, Rui J.; Lino, F. Jorge; Reis, Ana

2012-09-01

Total Hip Arthroplasty (THA) is a surgical intervention that is being achieving high rates of success, leaving room to research on long run durability, patient comfort and costs reduction. Even so, up to the present, little research has been done to improve the method of manufacturing customized prosthesis. The common customized prostheses are made by full machining. This document presents a different approach methodology which combines the study of medical images, through CAD (Computer Aided Design) software, SLadditive manufacturing, ceramic shell manufacture, precision foundry with Titanium alloys and Computer Aided Manufacturing (CAM). The goal is to achieve the best comfort for the patient, stress distribution and the maximum lifetime of the prosthesis produced by this integrated methodology. The way to achieve this desiderate is to make custom hip prosthesis which are adapted to each patient needs and natural physiognomy. Not only the process is reliable, but also represents a cost reduction comparing to the conventional full machined custom hip prosthesis.

Sensory feedback add-on for upper-limb prostheses.

PubMed

Fallahian, Nader; Saeedi, Hassan; Mokhtarinia, Hamidreza; Tabatabai Ghomshe, Farhad

2017-06-01

Sensory feedback systems have been of great interest in upper-limb prosthetics. Despite tremendous research, there are no commercial modality-matched feedback systems. This article aims to introduce the first detachable and feedback add-on option that can be attached to in-use prostheses. A sensory feedback system was tested on a below-elbow myoelectric prosthesis. The aim was to have the amputee grasp fragile objects without crushing while other accidental feedback sources were blocked. A total of 8 successful trials (out of 10) showed that sensory feedback system decreased the amputee's visual dependency by improving awareness of his prosthesis. Sensory feedback system can be used either as post-fabrication (prosthetic add-on option) or para-fabrication (incorporated into prosthetic design). The use of these direct feedback systems can be explored with a current prosthesis before ordering new high-tech prosthesis. Clinical relevance This technical note introduces the first attach/detach-able sensory feedback system that can simply be added to in-use (myo)electric prosthesis, with no obligation to change prosthesis design or components.

What are estimated reimbursements for lower extremity prostheses capable of surgical and nonsurgical lengthening?

PubMed

Henderson, Eric R; Pepper, Andrew M; Letson, G Douglas

2012-04-01

Growing prostheses accommodate skeletally immature patients with bone tumors undergoing limb-preserving surgery. Early devices required surgical procedures for lengthening; recent devices lengthen without surgery. Expenses for newer expandable devices that lengthen without surgery are more than for their predecessors but overall reimbursement amounts are not known. We sought to determine reimbursement amounts associated with lengthening of growing prostheses requiring surgical and nonsurgical lengthening. We retrospectively reviewed 17 patients with growing prostheses requiring surgical expansion and eight patients with prostheses capable of nonsurgical expansion. Insurance documents were reviewed to determine the reimbursement for implantation, lengthening, and complications. Growth data were obtained from the literature. Mean reimbursement amounts of surgical and nonsurgical lengthenings were $9950 and $272, respectively. Estimated reimbursements associated with implantation of a growing prosthesis varied depending on age, sex, and location. The largest difference was found for 4-year-old boys with distal femoral replacement where reimbursement for expansion to maturity for surgical and nonsurgical lengthening prostheses would be $379,000 and $208,000, respectively. For children requiring more than one surgical expansion, net reimbursements were lower when a noninvasive lengthening device was used. Annual per-prosthesis maintenance reimbursements to address complications for surgical and nonsurgical lengthening prostheses were $3386 and $1856, respectively. This study showed that reimbursements for lengthening of growing endoprostheses capable of nonsurgical expansion may be less expensive in younger patients, particularly male patients undergoing distal femur replacement, than endoprostheses requiring surgical lengthening. Longer outcomes studies are required to see if reimbursements for complications differ between devices. Level III, economic and decision analysis. See the Guidelines for Authors for a complete description of levels of evidence.

Malleus-to-footplate prosthetic interposition: experience with 265 patients.

PubMed

Colletti, V; Fiorino, F G

1999-03-01

Absence of the long process of the incus with or without absence of the stapes head accounts for more than 80% of ossicular discontinuities. Total or partial replacement prostheses, made of various materials, are interposed to restore the transfer function of the middle ear. To simplify ossicular reconstruction, reduce operative times and costs, improve functional outcomes, and avoid the risk of infections, we have adopted, during the past 10 years, a technique that makes use of a personally designed alloplastic prosthetic device. The prosthesis connects the malleus to the footplate, even in the presence of the stapes superstructure. This malleus-to-footplate prosthesis consists in a plastipore-coated steel piston and hydroxyapatite head, complete with a groove. The groove is placed beneath the malleus neck after dissection of the tensor tympani tendon and the shaft of the piston on the footplate. Two hundred ninety primary ossiculoplasties with the malleus-to-footplate prostheses were performed in 265 patients from 1986 to 1995 in the ENT Department of the University of Verona. The average postoperative air-bone gap at 0.5 to 3 kHz was 11 dB at 1 year and 14 dB at 5 years. These outcomes are significantly better than those personally obtained previously with ossicular or alloplastic prostheses. No extrusions occurred. The structural characteristics of the malleus-to-foot-plate prosthesis endow the prosthesis with a high degree of biocompatibility and stability and optimal sound-transfer function. The rationale for this particular ossiculoplasty procedure is discussed.

Prosthesis use in adult acquired major upper-limb amputees: patterns of wear, prosthetic skills and the actual use of prostheses in activities of daily life.

PubMed

Østlie, Kristin; Lesjø, Ingrid Marie; Franklin, Rosemary Joy; Garfelt, Beate; Skjeldal, Ola Hunsbeth; Magnus, Per

2012-11-01

To describe patterns of prosthesis wear and perceived prosthetic usefulness in adult acquired upper-limb amputees (ULAs). To describe prosthetic skills in activities of daily life (ADL) and the actual use of prostheses in the performance of ADL tasks. To estimate the influence of prosthetic skills on actual prosthesis use and the influence of background factors on prosthetic skills and actual prosthesis use. Cross-sectional study analysing population-based questionnaire data (n = 224) and data from interviews and clinical testing in a referred/convenience sample of prosthesis-wearing ULAs (n = 50). Effects were analysed using linear regression. 80.8% wore prostheses. 90.3% reported their most worn prosthesis as useful. Prosthetic usefulness profiles varied with prosthetic type. Despite demonstrating good prosthetic skills, the amputees reported actual prosthesis use in only about half of the ADL tasks performed in everyday life. In unilateral amputees, increased actual use was associated with sufficient prosthetic training and with the use of myoelectric vs cosmetic prostheses, regardless of amputation level. Prosthetic skills did not affect actual prosthesis use. No background factors showed significant effect on prosthetic skills. Most major ULAs wear prostheses. Individualised prosthetic training and fitting of myoelectric rather than passive prostheses may increase actual prosthesis use in ADL.

Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Çatlı, Serap, E-mail: serapcatli@hotmail.com; Tanır, Güneş

2013-10-01

The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18 MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the presentmore » study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.« less

21 CFR 872.3940 - Total temporomandibular joint prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Total temporomandibular joint prosthesis. 872.3940... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended to be...

21 CFR 872.3940 - Total temporomandibular joint prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Total temporomandibular joint prosthesis. 872.3940... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended to be...

[A therapeutic effect analysis of femur first principle and combined anteversion technique during total hip arthroplasty].

PubMed

Wang, X Q; Wu, C S; Sun, S; Wang, J; Li, W; Zhang, W

2018-04-01

Objective: To investigate the situation of hip dislocation with the application of "femur first" principle and "combined anteversion technique" during total hip arthroplasty. Methods: A retrospective analysis has been done on the clinical data about 104 patients(133 hips)who were diagnosed as hip disease and were treated with total hip arthroplasty by the doctors from the Department of Joint Orthorpaedics of Shandong Provincial Hospital Affiliated to Shandong University from June 2014 to June 2016, and all the prostheses applied in the operation were cementless ones.Among them, 65 patients were males, 39 females and their age was 46.6 years (ranging from 23 to 76 years) .And 29 of them underwent bilateral hip operations and 75 unilateral ones.Seventy-six cases of aseptic necrosis of the femoral head in the terminal stage, 28 cases of hip dysplasia and osteoarthritis.Surgical approach: of all the operations, 103 hips were operated on with hardinge approach, 30 with posterolateral approach.During the operation, first of all, the femoral medullary cavity was broached and then the anteversion of intramedullary broacher was measured.After that, the anteversion of the acetabular cup was calculated as 37° minus the anteversion of the broacher, and the acetabular cup was implanted at that angle.The patients' prosthesis combined anteversion, range of motion of the hip joint, operation time, hemorrhage amount, and complications had been kept record.One, three, and six months respectively after the operation, all the patients received outpatient review, and took anteroposterior and lateral position X-ray examination.Harris hip score had been applied to evaluate their hip function before the operation and six months after the operation. Results: All the patients had been operated on smoothly, with the operation time of(57.6±14.5)minutes(36-115 minutes)and hemorrhage amount of (336.5±50.8)ml(180-620 ml). The operation finding showed that the combined anteversion by employing"femur first"principle and combined anteversion techniqueis was (36.6±6.8)°. Also, range of motion of the patients' hip conforms to the D'Lima criterion and no patients had experienced dislocation and some other serious complications.The follow-up ended at August 2017, which lasted for 12.2 months(6-18 months), and 88 cases(119 hips) were interviewed. The Harris hip score for the affected sides of the hip joints 6 months after the surgery was 94.6(86-100). Compared with the score of 29.8(12-43) before surgery, the t -test had proven its statistical significance( t =12.82, P =0.003). Conclusion: Based upon the "femoral first" principle and "combined anteversion technique" during total hip arthroplasty, these operations has been carried out well enough to meet the patients' needs of performing normal daily activities.

Results after mitral valve replacement with cloth-covered Starr-Edwards prostheses (models 6300, 6310/6320, and 6400).

PubMed Central

Forman, R; Beck, W; Barnard, C N

1978-01-01

The actuarial survival and thromboembolic rates for the three types of cloth-covered Starr-Edwards mitral prostheses, models 6300, 6310/6320, and 6400 followed 6, 5, and 2 years, respectively, were not significantly different throughout the years they were followed. The combined cumulative survival and thromboembolic proportion at 5 years for these prostheses were 71 and 66 per cent, respectively. The thromboembolic rates were not different in the following two groups: (a) 238 patients receiving anticoagulants, and (b) 52 patients who had discontinued or who were not receiving anticoagulants. Four patients thrombosed their mitral prostheses. Another 8 per cent had class 3 symptoms after operation, which were attributed to myopathic or restrictive left ventricular dysfunction or other valvular disease. PMID:656234

Penile Prosthesis Implantation in Patients with a History of Total Phallic Construction.

PubMed

Zuckerman, Jack M; Smentkowski, Katherine; Gilbert, David; Storme, Oscar; Jordan, Gerald; Virasoro, Ramon; Tonkin, Jeremy; McCammon, Kurt

2015-12-01

Outcomes following penile prosthesis implantation in patients with a history of total phallic construction are not well described. The aim of this study was to evaluate outcomes following neophallus penile prosthesis placement. Retrospective review penile prosthesis placement in patients with prior total phallic construction. GORE-TEX® (Gore Medical, Flagstaff, AZ) sleeve neotunica construction was utilized in all patients. Success defined as patient sexual activity with a functioning prosthesis. Thirty-one patients underwent neophallic prosthesis implantation at a mean 35.6 years of age. Prosthesis placement occurred at an average 56.3 months following phallic construction and follow-up was a mean of 59.7 months. Malleable prostheses were placed in 21 patients and inflatable in 10; implants were bilateral in 94%. Six percent experienced operative complications including a bladder injury (1) and phallic flap arterial injury (1). Postoperative complications occurred in 23% at a median 5.5 months following placement. Five prostheses were explanted secondary to infection or erosion and two additional required revisions. Of the explanted prosthesis two were later replaced without further complication. Eighty-one percent of patients were sexually active following prosthesis placement. Penile prosthesis placement is possible in patients with prior penile reconstruction/phallic construction. Although complications rates appear to be elevated in this population compared with historic controls of normal anatomic men, the majority of patients in this series were sexually active following prosthesis placement. This demonstrates the utility of prosthesis implantation in these difficult patients. © 2015 International Society for Sexual Medicine.

[Design and optimization of wireless power and data transmission for visual prosthesis].

PubMed

Lei, Xuping; Wu, Kaijie; Zhao, Lei; Chai, Xinyu

2013-11-01

Boosting spatial resolution of visual prostheses is an effective method to improve implant subjects' visual perception. However, power consumption of visual implants greatly rises with the increasing number of implanted electrodes. In respond to this trend, visual prostheses need to develop high-efficiency wireless power transmission and high-speed data transmission. This paper presents a review of current research progress on wireless power and data transmission for visual prostheses, analyzes relative principles and requirement, and introduces design methods of power and data transmission.

Progress in the clinical development and utilization of vision prostheses: an update

PubMed Central

Brandli, Alice; Luu, Chi D; Guymer, Robyn H; Ayton, Lauren N

2016-01-01

Vision prostheses, or “bionic eyes”, are implantable medical bionic devices with the potential to restore rudimentary sight to people with profound vision loss or blindness. In the past two decades, this field has rapidly progressed, and there are now two commercially available retinal prostheses in the US and Europe, and a number of next-generation devices in development. This review provides an update on the development of these devices and a discussion on the future directions for the field. PMID:28539798

Dissociation of modular total hip arthroplasty at the neck-stem interface without dislocation.

PubMed

Kouzelis, A; Georgiou, C S; Megas, P

2012-12-01

Modular femoral and acetabular components are now widely used, but only a few complications related to the modularity itself have been reported. We describe a case of dissociation of the modular total hip arthroplasty (THA) at the femoral neck-stem interface during walking. The possible causes of this dissociation are discussed. Successful treatment was provided with surgical revision and replacement of the modular neck components. Surgeons who use modular components in hip arthroplasties should be aware of possible early complications in which the modularity of the prostheses is the major factor of failure.

Ultrasonographic assessment of the quadriceps muscle and femoral cartilage in transtibial amputees using different prostheses.

PubMed

Şahin Onat, Şule; Malas, Fevziye Ünsal; Öztürk, Gökhan Tuna; Akkaya, Nuray; Kara, Murat; Özçakar, Levent

2016-08-01

In patients with lower limb amputations, gait alteration, increased loading on the intact extremity, and use of prosthesis may lead to joint degeneration. To explore the effects of prosthesis type on quadriceps muscle and distal femoral cartilage thicknesses in transtibial amputees. A cross-sectional study. A total of 38 below-knee amputees were enrolled in the study, of which 13 patients were using vacuum system type prosthesis and 25 patients were using silicon liner pin system prosthesis. Patients' femoral cartilage and quadriceps muscle thickness measurements were performed using musculoskeletal ultrasound. When compared with the intact sides, cartilage and rectus femoris, vastus intermedius, and vastus medialis muscle thickness values were significantly decreased on the amputee sides (all p < 0.05). Clinical characteristics and ultrasound measurements were similar between the two groups except the lateral and medial femoral condyle thicknesses, thinner in the silicon liner pin system users (both p < 0.05). The distal femoral cartilage and quadriceps muscle thicknesses were found to be decreased on the amputated sides, and the negative impact on the cartilage seemed to be worse in the silicon liner pin system users. This study might provide another argument as regards the preference of vacuum system type prosthesis to prevent possible knee osteoarthritis due to cartilage thinning in adult transtibial amputees. © The International Society for Prosthetics and Orthotics 2015.

Probabilistic analysis of the influence of the bonding degree of the stem-cement interface in the performance of cemented hip prostheses.

PubMed

Pérez, M A; Grasa, J; García-Aznar, J M; Bea, J A; Doblaré, M

2006-01-01

The long-term behavior of the stem-cement interface is one of the most frequent topics of discussion in the design of cemented total hip replacements, especially with regards to the process of damage accumulation in the cement layer. This effect is analyzed here comparing two different situations of the interface: completely bonded and debonded with friction. This comparative analysis is performed using a probabilistic computational approach that considers the variability and uncertainty of determinant factors that directly compromise the damage accumulation in the cement mantle. This stochastic technique is based on the combination of probabilistic finite elements (PFEM) and a cumulative damage approach known as B-model. Three random variables were considered: muscle and joint contact forces at the hip (both for walking and stair climbing), cement damage and fatigue properties of the cement. The results predicted that the regions with higher failure probability in the bulk cement are completely different depending on the stem-cement interface characteristics. In a bonded interface, critical sites appeared at the distal and medial parts of the cement, while for debonded interfaces, the critical regions were found distally and proximally. In bonded interfaces, the failure probability was higher than in debonded ones. The same conclusion may be established for stair climbing in comparison with walking activity.

Usefulness of magnetic resonance imaging in the postsurgical assessment of patients with inflatable penile prostheses.

PubMed

Pacheco Usmayo, A; Torregrosa Andrés, A; Flores Méndez, J; Luján Marco, S; Rogel Bertó, R

To describe the types of penile prostheses and their components, to review the appropriate magnetic resonance imaging (MRI) acquisition protocol, and to describe the normal imaging findings and possible complications in patients with inflatable penile implants. Three-piece inflatable penile prostheses are the last link in the treatment chain for erectile dysfunction. They can develop complications, which are classified as non-infectious related to the surgical technique, infectious, or due to mechanical failure of the device. MRI is the most appropriate imaging technique for the postsurgical evaluation of penile prostheses. Images are acquired in three planes using sequences with high spatial resolution, first with the prosthesis at rest and then with the prosthesis activated. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Appearance of low signal intensity lines in MRI of silicone breast implants.

PubMed

Stroman, P W; Rolland, C; Dufour, M; Grondin, P; Guidoin, R G

1996-05-01

Magnetic resonance (MR) images of five explanted mammary prostheses were obtained with a 1.5 T GE Signa system using a conventional spin-echo pulse sequence, in order to investigate the low-intensity curvilinear lines which may be observed in MR images of silicone gel-filled breast implants under pressure from fibrous capsules. MR images showed ellipsoid prostheses, often containing multiple low-intensity curvilinear lines which in some cases presented an appearance very similar to that of the linguine sign. Upon opening the fibrous capsules, however, all of the prostheses were found to be completely intact demonstrating that the appearance of multiple low signal intensity curvilinear lines in MR images of silicone gel-filled prostheses is not necessarily a sign of prosthesis rupture. The MR image features which are specific to the linguine sign must be more precisely defined.

["Bionic" arm prostheses. State of the art in research and development].

PubMed

Pylatiuk, C; Döderlein, L

2006-11-01

A new generation of arm prostheses is being developed worldwide. These so-called bionic prostheses are intended to offer additional functions, such as sensory feedback, extended range of possible movement, intuitive movement control as far as possible, and a more natural cosmetic appearance. In recent years, prosthetic components with much enhanced performance have been developed for use at various levels of the upper limb. Artificial hands that allow for additional grips are are being tested in clinical settings. Innovative methods of signal acquisition and communication with the patient are being intensively researched. Several patients have been provided with prototypes of new arm prostheses. At the moment, the results are limited by the restricted communication between patient and prosthesis. However, we can expect the options for prosthesis control to be extended in the near future.

A Three-Dimensional Finite Element Analysis of the Stress Distribution Generated by Splinted and Nonsplinted Prostheses in the Rehabilitation of Various Bony Ridges with Regular or Short Morse Taper Implants.

PubMed

Toniollo, Marcelo Bighetti; Macedo, Ana Paula; Rodrigues, Renata Cristina; Ribeiro, Ricardo Faria; de Mattos, Maria G

The aim of this study was to compare the biomechanical performance of splinted or nonsplinted prostheses over short- or regular-length Morse taper implants (5 mm and 11 mm, respectively) in the posterior area of the mandible using finite element analysis. Three-dimensional geometric models of regular implants (Ø 4 × 11 mm) and short implants (Ø 4 × 5 mm) were placed into a simulated model of the left posterior mandible that included the first premolar tooth; all teeth posterior to this tooth had been removed. The four experimental groups were as follows: regular group SP (three regular implants were rehabilitated with splinted prostheses), regular group NSP (three regular implants were rehabilitated with nonsplinted prostheses), short group SP (three short implants were rehabilitated with splinted prostheses), and short group NSP (three short implants were rehabilitated with nonsplinted prostheses). Oblique forces were simulated in molars (365 N) and premolars (200 N). Qualitative and quantitative analyses of the minimum principal stress in bone were performed using ANSYS Workbench software, version 10.0. The use of splinting in the short group reduced the stress to the bone surrounding the implants and tooth. The use of NSP or SP in the regular group resulted in similar stresses. The best indication when there are short implants is to use SP. Use of NSP is feasible only when regular implants are present.

PubMed Central

BOLZONI, A.; MAPELLI, A.; BAJ, A.; SIDEQUERSKY, F.V; GIANNÌ, A.B.

2015-01-01

SUMMARY Seven patients who underwent mandibular reconstruction with a fibula free flap (one on the midline, six on either right or left side) and were rehabilitated with implant supported prostheses, performed free mandibular border movements (maximal mouth opening and closing, right and left lateral excursions, protrusion) that were recorded by a non-invasive motion analyser. Temporomandibular joint (TMJ) kinematic parameters were compared to those calculated in healthy control subjects using z-scores. Maximum mouth opening was reduced in all patients, with z-scores ranging from -2.742 to -0.106, and performed with a reduced sagittal plane mandibular rotation. Interincisal point forward movement during protrusion was reduced in all but one patient. Lateral mandibular movements (displacement of the interincisal point) and bilateral condylar movements during mouth opening were very variable and sometimes asymmetrical. Mandibular rotation was also variable, with z-scores ranging from -1.265 to 1.388. Together with mandibular range of motion, we investigated biomechanical characteristics of TMJ motion that can provide further information about the joint without submitting the patient to harmful procedures, and that can be followed-up during healing. The investigation indicates those areas that need to be given special attention in preoperative planning, patient information and rehabilitation. PMID:26900241

CAD-CAM-generated hydroxyapatite scaffold to replace the mandibular condyle in sheep: preliminary results.

PubMed

Ciocca, Leonardo; Donati, Davide; Fantini, Massimiliano; Landi, Elena; Piattelli, Adriano; Iezzi, Giovanna; Tampieri, Anna; Spadari, Alessandro; Romagnoli, Noemi; Scotti, Roberto

2013-08-01

In this study, rapid CAD-CAM prototyping of pure hydroxyapatite to replace temporomandibular joint condyles was tested in sheep. Three adult animals were implanted with CAD-CAM-designed porous hydroxyapatite scaffolds as condyle substitutes. The desired scaffold shape was achieved by subtractive automated milling machining (block reduction). Custom-made surgical guides were created by direct metal laser sintering and were used to export the virtual planning of the bone cut lines into the surgical environment. Using the same technique, fixation plates were created and applied to the scaffold pre-operatively to firmly secure the condyles to the bone and to assure primary stability of the hydroxyapatite scaffolds during masticatory function. Four months post-surgery, the sheep were sacrificed. The hydroxyapatite scaffolds were explanted, and histological specimens were prepared. Different histological tissues penetrating the scaffold macropores, the sequence of bone remodeling, new apposition of bone and/or cartilage as a consequence of the different functional anatomic role, and osseointegration at the interface between the scaffold and bone were documented. This animal model was found to be appropriate for testing CAD-CAM customization and the biomechanical properties of porous, pure hydroxyapatite scaffolds used as joint prostheses.

Experimental effective shape control of a powered transfemoral prosthesis.

PubMed

Gregg, Robert D; Lenzi, Tommaso; Fey, Nicholas P; Hargrove, Levi J; Sensinger, Jonathon W

2013-06-01

This paper presents the design and experimental implementation of a novel feedback control strategy that regulates effective shape on a powered transfemoral prosthesis. The human effective shape is the effective geometry to which the biological leg conforms--through movement of ground reaction forces and leg joints--during the stance period of gait. Able-bodied humans regulate effective shapes to be invariant across conditions such as heel height, walking speed, and body weight, so this measure has proven to be a very useful tool for the alignment and design of passive prostheses. However, leg joints must be actively controlled to assume different effective shapes that are unique to tasks such as standing, walking, and stair climbing. Using our previous simulation studies as a starting point, we model and control the effective shape as a virtual kinematic constraint on the powered Vanderbilt prosthetic leg with a custom instrumented foot. An able-bodied subject used a by-pass adapter to walk on the controlled leg over ground and over a treadmill. These preliminary experiments demonstrate, for the first time, that effective shape (or virtual constraints in general) can be used to control a powered prosthetic leg.

Incus replacement prostheses of hydroxylapatite in middle ear reconstruction.

PubMed

Wehrs, R E

1989-05-01

Hydroxylapatite is a calcium bioceramic that has the same chemical composition as living bone, Ca10 (PO4) 6 (OH) 2. Since 1970 it has been used as a material in reconstructive prostheses and augmentation of lost tissues in various surgical specialties including maxillofacial surgery, plastic surgery, otolaryngology, and orthopedics. For over 20 years the author has used autograft and homograft ossicles in tympanoplasty. These incudi have been modified into prostheses that were utilized in ossicular reconstruction. During this time two principle prostheses have evolved, the notched incus with short and long processes. The short process prosthesis is used with an intact stapes, whereas the notched incus with long process carries the sound pressure directly to the stapedial footplate. These prostheses have been successful in improving and maintaining hearing following tympanoplasty. Unfortunately, however, the use of human tissue has certain limitations: it is not readily accessible and has a limited shelf life. Furthermore, clinicians are wary of using homograft tissue as concern over the AIDS virus spreads. Therefore it was felt prudent to develop a manmade prosthesis that would as nearly as possible match the advantages of living bone. Hydroxylapetite most nearly met those qualifications.

Prototyping for surgical and prosthetic treatment.

PubMed

Goiato, Marcelo Coelho; Santos, Murillo Rezende; Pesqueira, Aldiéris Alves; Moreno, Amália; dos Santos, Daniela Micheline; Haddad, Marcela Filié

2011-05-01

Techniques of rapid prototyping were introduced in the 1980s in the field of engineering for the fabrication of a solid model based on a computed file. After its introduction in the biomedical field, several applications were raised for the fabrication of models to ease surgical planning and simulation in implantology, neurosurgery, and orthopedics, as well as for the fabrication of maxillofacial prostheses. Hence, the literature has described the evolution of rapid prototyping technique in health care, which allowed easier technique, improved surgical results, and fabrication of maxillofacial prostheses. Accordingly, a literature review on MEDLINE (PubMed) database was conducted using the keywords rapid prototyping, surgical planning, and maxillofacial prostheses and based on articles published from 1981 to 2010. After reading the titles and abstracts of the articles, 50 studies were selected owing to their correlations with the aim of the current study. Several studies show that the prototypes have been used in different dental-medical areas such as maxillofacial and craniofacial surgery; implantology; neurosurgery; orthopedics; scaffolds of ceramic, polymeric, and metallic materials; and fabrication of personalized maxillofacial prostheses. Therefore, prototyping has been an indispensable tool in several studies and helpful for surgical planning and fabrication of prostheses and implants.

Prostheses and orthoses in the collections of the Auschwitz-Birkenau State Museum.

PubMed

Przeździak, Bogumił; Lutomirski, Adam; Kulczyk, Maria

2011-01-01

The authors described 424 orthopaedic appliances left by the prisoners of the Nazi Concentration Camp in Oświęcim. A collection of prostheses and orthoses, which is currently a part of the Auschwitz-Birkenau State Museum's exhibition, is extraordinary as it illustrates the fate of innocent, crippled people, who were incarcerated and murdered. Another point of value of the collection is its technical aspect, as it provides a clear picture of construction of prostheses and orthoses at the beginning of the 20th century.

Secondary patella resurfacing in painful non-resurfaced total knee arthroplasties : A study of survival and clinical outcome from the Norwegian Arthroplasty Register (1994-2011).

PubMed

Leta, Tesfaye H; Lygre, Stein Håkon L; Skredderstuen, Arne; Hallan, Geir; Gjertsen, Jan-Erik; Rokne, Berit; Furnes, Ove

2016-04-01

In Norway, 19 % of revisions of non-resurfaced total knee arthroplasties done for knee pain between 1994 and 2011 were Secondary Patella Resurfacing (SPR). It is, however, unclear whether SPR actually resolves the pain. The aim was to investigate prostheses survival and clinical outcomes following SPR. A total of 308 knees (301 patients) with SPR were used to assess implant survival, and a sub-cohort (n = 114 out of 301 patients) with Patient Reported Outcome Measures (PROMs) data were used to assess the clinical outcomes. The EuroQol (EQ-5D), the Knee Injury and Osteoarthritis Outcome Score, and Visual Analogue Scales on satisfaction and pain were used to collect PROM data. Outcomes were analysed by Kaplan-Meier, Cox regression, and multiple linear regression. The five- and ten-year Kaplan-Meier survival percentages were 91 % and 87 %, respectively. Overall, 35 knees were re-revised at a median follow-up of eight years and pain alone (10 knees) was the main cause of re-revision. Younger patients (<60 years) had nearly nine times higher risk of re-revision compared to older patients (>70 years) (RR = 8.6; p < 0.001). Mean EQ-5D index score had improved from 0.41 (SD 0.21) preoperative to 0.56 (SD 0.25) postoperative following SPR. A total of 63 % of patients with PROM data were satisfied with the outcomes of SPR. The long-term prostheses survival following SPR was satisfactory, although not as good as for primary knee replacement. Patients' health related quality of life improved significantly following SPR. Still, more than a third of patients with PROMs data were dissatisfied with the outcomes of the SPR procedure.

Trends in Computer-Aided Manufacturing in Prosthodontics: A Review of the Available Streams

PubMed Central

Bennamoun, Mohammed

2014-01-01

In prosthodontics, conventional methods of fabrication of oral and facial prostheses have been considered the gold standard for many years. The development of computer-aided manufacturing and the medical application of this industrial technology have provided an alternative way of fabricating oral and facial prostheses. This narrative review aims to evaluate the different streams of computer-aided manufacturing in prosthodontics. To date, there are two streams: the subtractive and the additive approaches. The differences reside in the processing protocols, materials used, and their respective accuracy. In general, there is a tendency for the subtractive method to provide more homogeneous objects with acceptable accuracy that may be more suitable for the production of intraoral prostheses where high occlusal forces are anticipated. Additive manufacturing methods have the ability to produce large workpieces with significant surface variation and competitive accuracy. Such advantages make them ideal for the fabrication of facial prostheses. PMID:24817888

[An experimental study of the coagulating properties of a laser beam applied to fix titanium prostheses of auditory ossicles with the use of platelet-rich plasma].

PubMed

Semenov, V F; Semenov, F V

2013-01-01

The displacement of prostheses of auditory ossicles at the concluding stage of surgery and in the early postoperative period is one of the factors influencing the functional outcome of stapedoplasty. The objective of the present experimental study was to estimate the effectiveness of the use of platelet-rich plasma as an alloy for the laser welding in order to improve fixation of titanium prostheses employed in ossiculoplastic surgery. The results of a series of experiments undertaken to assess the possibility of stabilization of titanium prostheses in the desired position with the help of laser welding indicate that this technique with the use of platelet-rich plasma as an alloy may be a reliable method for the fixation of the reconstructed chain of ossicles in the desired position.

Implant-retained craniofacial prostheses for facial defects

PubMed Central

Federspil, Philipp A.

2012-01-01

Craniofacial prostheses, also known as epistheses, are artificial substitutes for facial defects. The breakthrough for rehabilitation of facial defects with implant-retained prostheses came with the development of the modern silicones and bone anchorage. Following the discovery of the osseointegration of titanium in the 1950s, dental implants have been made of titanium in the 1960s. In 1977, the first extraoral titanium implant was inserted in a patient. Later, various solitary extraoral implant systems were developed. Grouped implant systems have also been developed which may be placed more reliably in areas with low bone presentation, as in the nasal and orbital region, or the ideally pneumatised mastoid process. Today, even large facial prostheses may be securely retained. The classical atraumatic surgical technique has remained an unchanged prerequisite for successful implantation of any system. This review outlines the basic principles of osseointegration as well as the main features of extraoral implantology. PMID:22073096

[In situ aortofemoral reconstructions in surgical treatment of infected aortofemoral grafts].

PubMed

Badretdinov, I A; Pokrovsky, A V

2015-01-01

The article presents a review of literature sources covering possibilities of peiforming in situ aortofemoral reconstructions in surgical treatment of infected aortofemoral grafts. This methodology makes it possible to improve the outcomes of treatment for paraprosthetic infection at the expense of decreasing lethality and morbidity, increasing parameters of patency of grafts and lower limb salvage in the remote postoperative period. Mention should be made that in situ secondary aortofemoral reconstructions are fraught with danger of relapsing paraprosthetic infection, therefore many publications are dedicated to search for prostheses most resistant to infection. The article also presents the results of works devoted to the use of various types of prostheses for in situ secondary aortofemoral reconstructions: prostheses made of polytetrafluoroethylene (PTFE), synthetic grafts saturated with various antibacterial drugs and gelatine, cadaveric allografts, synthetic prostheses treated with silver ions, autovenous conduits based on the femoral and popliteal veins.

Reflections on the present and future of upper limb prostheses.

PubMed

Farina, Dario; Amsüss, Sebastian

2016-01-01

Despite progress in research and media attention on active upper limb prostheses, presently the most common commercial upper limb prosthetic devices are not fundamentally different from solutions offered almost one century ago. Limited information transfer for both control and sensory-motor integration and challenges in socket technology have been major obstacles. By analysing the present state-of-the-art and academic achievements, we provide our opinion on the future of upper limb prostheses. We believe that surgical procedures for muscle reinnervation and osseointegration will become increasingly clinically relevant; muscle electrical signals will remain the main clinical means for prosthetic control; and chronic electrode implants, first in muscles (control), then in nerves (sensory feedback), will become viable clinical solutions. After decades of suspended clinically relevant progress, it is foreseeable that a new generation of upper limb prostheses will enter the market in the near future based on such advances, thereby offering substantial clinical benefit for patients.

Vibrotactile grasping force and hand aperture feedback for myoelectric forearm prosthesis users.

PubMed

Witteveen, Heidi J B; Rietman, Hans S; Veltink, Peter H

2015-06-01

User feedback about grasping force and hand aperture is very important in object handling with myoelectric forearm prostheses but is lacking in current prostheses. Vibrotactile feedback increases the performance of healthy subjects in virtual grasping tasks, but no extensive validation on potential users has been performed. Investigate the performance of upper-limb loss subjects in grasping tasks with vibrotactile stimulation, providing hand aperture, and grasping force feedback. Cross-over trial. A total of 10 subjects with upper-limb loss performed virtual grasping tasks while perceiving vibrotactile feedback. Hand aperture feedback was provided through an array of coin motors and grasping force feedback through a single miniature stimulator or an array of coin motors. Objects with varying sizes and weights had to be grasped by a virtual hand. Percentages correctly applied hand apertures and correct grasping force levels were all higher for the vibrotactile feedback condition compared to the no-feedback condition. With visual feedback, the results were always better compared to the vibrotactile feedback condition. Task durations were comparable for all feedback conditions. Vibrotactile grasping force and hand aperture feedback improves grasping performance of subjects with upper-limb loss. However, it should be investigated whether this is of additional value in daily-life tasks. This study is a first step toward the implementation of sensory vibrotactile feedback for users of myoelectric forearm prostheses. Grasping force feedback is crucial for optimal object handling, and hand aperture feedback is essential for reduction of required visual attention. Grasping performance with feedback is evaluated for the potential users. © The International Society for Prosthetics and Orthotics 2014.

Influence of transmucosal height in abutments of single and multiple implant-supported prostheses: a non-linear three-dimensional finite element analysis.

PubMed

Borie, Eduardo; Leal, Eduardo; Orsi, Iara Augusta; Salamanca, Carlos; Dias, Fernando José; Weber, Benjamin

2018-01-01

The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.

Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.

PubMed

Santavirta, Seppo

2003-12-01

Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip.

Isokinetic strength differences between patients with primary reverse and total shoulder prostheses: muscle strength quantified with a dynamometer.

PubMed

Alta, Tjarco D W; Veeger, DirkJan H E J; de Toledo, Joelly M; Janssen, Thomas W J; Willems, W Jaap

2014-11-01

Range of motion after total shoulder arthroplasty is better than after reverse shoulder arthroplasty, however with similar clinical outcome. It is unclear if this difference can only be found in the different range of motion or also in the force generating capacity. (1) are isokinetically produced joint torques of reverse shoulder arthroplasty comparable to those of total shoulder arthroplasty? (2) Does this force-generating capacity correlate with functional outcome? Eighteen reverse shoulder arthroplasty patients (71years (SD 9years)) (21 shoulders, follow-up of 21months (SD 10months)) were recruited, 12 total shoulder arthroplasty patients (69years (SD 9years)) (14 shoulders, follow-up of 35months (SD 11months)). Pre- and post-operative Constant-Murley scores were obtained; two isokinetic protocols (ab-/adduction and ex-/internal rotations) at 60°/s were performed. Twelve of 18 reverse shoulder arthroplasty patients generated enough speed to perform the test (13 shoulders). Mean ab-/adduction torques are 16.3Nm (SD 5.6Nm) and 20.4Nm (SD 11.8Nm). All total shoulder arthroplasty patients generated enough speed (14 shoulders). Mean ab-/adduction torques are 32.1Nm (SD 13.3Nm) and 43.1Nm (SD 21.5Nm). Only 8 reverse shoulder arthroplasty patients (9 shoulders) could perform ex-/internal rotation tasks and all total shoulder arthroplasty patients. Mean ex-/internal rotation torques are 9.3Nm (SD 4.7Nm) and 9.2Nm (SD 2.1Nm) for reverse shoulder arthroplasty, and 17.9Nm (SD 7.7Nm) and 23.5Nm (SD 10.6Nm) for total shoulder arthroplasty. Significant correlations between sub-scores: activity, mobility and strength and external rotation torques for reverse shoulder arthroplasty. Moderate to strong correlation for sub-scores: strength in relation to abduction, adduction and internal rotation torques for total shoulder arthroplasty. Shoulders with a total shoulder arthroplasty are stronger. This can be explained by the absence of rotator cuff muscles and (probably) medialized center of rotation in reverse shoulder arthroplasty. The strong correlation between external rotation torques and post-operative Constant-Murley sub-scores demonstrates that external rotation is essential for good clinical functioning in reverse shoulder arthroplasty. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of alignment changes on socket reaction moments during gait in transfemoral and knee-disarticulation prostheses: case series.

PubMed

Kobayashi, Toshiki; Orendurff, Michael S; Boone, David A

2013-09-27

The alignment of a lower-limb prosthesis is critical to the successful prosthetic fitting and utilization by the wearer. Loads generated by the socket applied to the residual limb while walking are thought to be different in transfemoral and knee-disarticulation prostheses. The aim of this case series was to compare the socket reaction moments between transfemoral and knee-disarticulation prostheses and to investigate the effect of alignment changes on them. Two amputees, one with a transfemoral prosthesis and another with a knee-disarticulation prosthesis, participated in this study. A Smart Pyramid™ was used to measure socket reaction moments while walking under 9 selected alignment conditions; including nominally aligned, angle malalignments of 6° (flexion, extension, abduction and adduction) and translation malalignments of 15 mm (anterior, posterior, medial and lateral) of the socket relative to the foot. This study found that the pattern of the socket reaction moments was similar between transfemoral and knee-disarticulation prostheses. An extension moment in the sagittal plane and a varus moment in the coronal plane were dominant during stance under the nominally aligned condition. This study also demonstrated that alignment changes might have consistent effects on the socket reaction moments in transfemoral and knee-disarticulation prostheses. Extension and posterior translation of the socket resulted in increases in an extension moment, while abduction and lateral translation of the socket resulted in increases in a varus moment. The socket reaction moments may potentially serve as useful biomechanical parameters to evaluate alignment in transfemoral and knee-disarticulation prostheses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Temperature variations in sintering ovens for metal ceramic dental prostheses: non-destructive assessment using OCT

NASA Astrophysics Data System (ADS)

Sinescu, C.; Bradu, A.; Duma, V.-F.; Topala, F. I.; Negrutiu, M. L.; Podoleanu, A. G.

2018-02-01

We present a recent investigation regarding the use of optical coherence tomography (OCT) in the monitoring of the calibration loss of sintering ovens for the manufacturing of metal ceramic dental prostheses. Differences in the temperatures of such ovens with regard to their specifications lead to stress and even cracks in the prostheses material, therefore to the failure of the dental treatment. Evaluation methods of the ovens calibration consist nowadays of firing supplemental samples; this is subjective, expensive, and time consuming. Using an in-house developed swept source (SS) OCT system, we have demonstrated that a quantitative assessment of the internal structure of the prostheses, therefore of the temperature settings of the ovens can be made. Using en-face OCT images acquired at similar depths inside the samples, the differences in reflectivity allow for the evaluation of the differences in granulation (i.e., in number and size of ceramic grains) of the prostheses material. Fifty samples, divided in five groups, each sintered at different temperatures (lower, higher, or equal to the prescribed one) have been analyzed. The consequences of the temperature variations with regard to the one prescribed were determined. Rules-of-thumb were extracted to monitor objectively, using only OCT images of currently manufactured samples, the settings of the oven. The method proposed allows for avoiding producing prostheses with defects. While such rules-of-thumb achieve a qualitative assessment, an insight in our on-going work on the quantitative assessment of such losses of calibration on dental ovens using OCT is also made.

Retention System and Splinting on Morse Taper Implants in the Posterior Maxilla by 3D Finite Element Analysis.

PubMed

Lemos, Cleidiel Aparecido Araujo; Verri, Fellippo Ramos; Santiago, Joel Ferreira; Almeida, Daniel Augusto de Faria; Batista, Victor Eduardo de Souza; Noritomi, Pedro Yoshito; Pellizzer, Duardo Piza

2018-01-01

The purpose of this study was to evaluate different retention systems (cement- or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σmax). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.

3D printing and intraoperative neuronavigation tailoring for skull base reconstruction after extended endoscopic endonasal surgery: proof of concept.

PubMed

Essayed, Walid I; Unadkat, Prashin; Hosny, Ahmed; Frisken, Sarah; Rassi, Marcio S; Mukundan, Srinivasan; Weaver, James C; Al-Mefty, Ossama; Golby, Alexandra J; Dunn, Ian F

2018-03-02

OBJECTIVE Endoscopic endonasal approaches are increasingly performed for the surgical treatment of multiple skull base pathologies. Preventing postoperative CSF leaks remains a major challenge, particularly in extended approaches. In this study, the authors assessed the potential use of modern multimaterial 3D printing and neuronavigation to help model these extended defects and develop specifically tailored prostheses for reconstructive purposes. METHODS Extended endoscopic endonasal skull base approaches were performed on 3 human cadaveric heads. Preprocedure and intraprocedure CT scans were completed and were used to segment and design extended and tailored skull base models. Multimaterial models with different core/edge interfaces were 3D printed for implantation trials. A novel application of the intraoperative landmark acquisition method was used to transfer the navigation, helping to tailor the extended models. RESULTS Prostheses were created based on preoperative and intraoperative CT scans. The navigation transfer offered sufficiently accurate data to tailor the preprinted extended skull base defect prostheses. Successful implantation of the skull base prostheses was achieved in all specimens. The progressive flexibility gradient of the models' edges offered the best compromise for easy intranasal maneuverability, anchoring, and structural stability. Prostheses printed based on intraprocedure CT scans were accurate in shape but slightly undersized. CONCLUSIONS Preoperative 3D printing of patient-specific skull base models is achievable for extended endoscopic endonasal surgery. The careful spatial modeling and the use of a flexibility gradient in the design helped achieve the most stable reconstruction. Neuronavigation can help tailor preprinted prostheses.

Paré and prosthetics: the early history of artificial limbs.

PubMed

Thurston, Alan J

2007-12-01

There is evidence for the use of prostheses from the times of the ancient Egyptians. Prostheses were developed for function, cosmetic appearance and a psycho-spiritual sense of wholeness. Amputation was often feared more than death in some cultures. It was believed that it not only affected the amputee on earth, but also in the afterlife. The ablated limbs were buried and then disinterred and reburied at the time of the amputee's death so the amputee could be whole for eternal life. One of the earliest examples comes from the 18th dynasty of ancient Egypt in the reign of Amenhotep II in the fifteenth century bc. A mummy in the Cairo Museum has clearly had the great toe of the right foot amputated and replaced with a prosthesis manufactured from leather and wood. The first true rehabilitation aids that could be recognized as prostheses were made during the civilizations of Greece and Rome. During the Dark Ages prostheses for battle and hiding deformity were heavy, crude devices made of available materials - wood, metal and leather. Such were the materials available to Ambroise Paré who invented both upper-limb and lower-limb prostheses. His 'Le Petit Lorrain', a mechanical hand operated by catches and springs, was worn by a French Army captain in battle. Subsequent refinements in medicine, surgery and prosthetic science greatly improved amputation surgery and the function of prostheses. What began as a modified crutch with a wooden or leather cup and progressed through many metamorphoses has now developed into a highly sophisticated prosthetic limb made of space-age materials.

Metal artifact reduction software used with abdominopelvic dual-energy CT of patients with metal hip prostheses: assessment of image quality and clinical feasibility.

PubMed

Han, Seung Chol; Chung, Yong Eun; Lee, Young Han; Park, Kwan Kyu; Kim, Myeong Jin; Kim, Ki Whang

2014-10-01

The objective of our study was to determine the feasibility of using Metal Artifact Reduction (MAR) software for abdominopelvic dual-energy CT in patients with metal hip prostheses. This retrospective study included 33 patients (male-female ratio, 19:14; mean age, 63.7 years) who received total hip replacements and 20 patients who did not have metal prostheses as the control group. All of the patients underwent dual-energy CT. The quality of the images reconstructed using the MAR algorithm and of those reconstructed using the standard reconstruction was evaluated in terms of the visibility of the bladder wall, pelvic sidewall, rectal shelf, and bone-prosthesis interface and the overall diagnostic image quality with a 4-point scale. The mean and SD attenuation values in Hounsfield units were measured in the bladder, pelvic sidewall, and rectal shelf. For validation of the MAR interpolation algorithm, pelvis phantoms with small bladder "lesions" and metal hip prostheses were made, and images of the phantoms both with and without MAR reconstruction were evaluated. Image quality was significantly better with MAR reconstruction than without at all sites except the rectal shelf, where the image quality either had not changed or had worsened after MAR reconstruction. The mean attenuation value was changed after MAR reconstruction to its original expected value at the pelvic sidewall (p < 0.001) and inside the bladder (p < 0.001). The SD attenuation value was significantly decreased after MAR reconstruction at the pelvic sidewall (p = 0.019) but did not show significant differences at the bladder (p = 0.173) or rectal shelf (p = 0.478). In the phantom study, all lesions obscured by metal artifacts on the standard reconstruction images were visualized after MAR reconstruction; however, new artifacts had developed in other parts of the MAR reconstruction images. The use of MAR software with dual-energy CT decreases metal artifacts and increases diagnostic confidence in the assessment of the pelvic cavity but also introduces new artifacts that can obscure pelvic structures.

Bony integration of titanium implants with a novel bioactive calcium titanate (Ca4Ti3O10) surface treatment in a rabbit model.

PubMed

Haenle, Maximilian; Lindner, Tobias; Ellenrieder, Martin; Willfahrt, Manfred; Schell, Hanna; Mittelmeier, Wolfram; Bader, Rainer

2012-10-01

Nowadays total joint replacement is an indispensable component of modern medicine. The surfaces characteristics of cementless prostheses may be altered to achieve an accelerated and enduring bony integration. Classic surface coatings bear the risk of loosening or flaking from the implant body. This risk is excluded by the chemical conversion of the naturally existing TiO(2) surface layer into calcium titanate. The aim of this experimental animal study was to investigate the bony integration of implants with a new calcium titanate surface (Ca(4)Ti(3)O(10)) compared with a conventional standard Ti6Al4V surface. Cylindrical implants, made of titanium alloy (Ti6Al4V) were implanted in both lateral femoral condyles of New Zealand white rabbits. In each animal, an implant with and without surface treatment was inserted in a blinded manner. Animals were sacrificed after 4, 12, and 36 weeks, respectively. The axial pull-off forces were determined for 25 animals using a universal testing machine (Zwick Z010, Ulm, Germany). Furthermore, a histological analysis of the bony integration of the implants was performed in 12 specimens. In general, the pull-off forces for untreated and treated implants increased with longer survival times of the rabbits. No significant difference could be shown after 4 weeks between treated and untreated implants. After 12 weeks, the treated implants revealed a statistical significant higher pull-off force. After 36 weeks, the pull-off forces for treated and untreated implants aligned again. Titanium implants treated with calcium titanate, may offer an interesting and promising implant surface modification for endoprosthetic implants. They might lead to an accelerated osseointegration of total hip and knee replacements. Copyright © 2012 Wiley Periodicals, Inc.

Application of real-time machine learning to myoelectric prosthesis control: A case series in adaptive switching.

PubMed

Edwards, Ann L; Dawson, Michael R; Hebert, Jacqueline S; Sherstan, Craig; Sutton, Richard S; Chan, K Ming; Pilarski, Patrick M

2016-10-01

Myoelectric prostheses currently used by amputees can be difficult to control. Machine learning, and in particular learned predictions about user intent, could help to reduce the time and cognitive load required by amputees while operating their prosthetic device. The goal of this study was to compare two switching-based methods of controlling a myoelectric arm: non-adaptive (or conventional) control and adaptive control (involving real-time prediction learning). Case series study. We compared non-adaptive and adaptive control in two different experiments. In the first, one amputee and one non-amputee subject controlled a robotic arm to perform a simple task; in the second, three able-bodied subjects controlled a robotic arm to perform a more complex task. For both tasks, we calculated the mean time and total number of switches between robotic arm functions over three trials. Adaptive control significantly decreased the number of switches and total switching time for both tasks compared with the conventional control method. Real-time prediction learning was successfully used to improve the control interface of a myoelectric robotic arm during uninterrupted use by an amputee subject and able-bodied subjects. Adaptive control using real-time prediction learning has the potential to help decrease both the time and the cognitive load required by amputees in real-world functional situations when using myoelectric prostheses. © The International Society for Prosthetics and Orthotics 2015.

A Three-Year Retrospective Study on Survival of Ceramic-Veneered Zirconia (Y-TZP) Fixed Dental Prostheses Performed in Private Practices

PubMed Central

Norström Saarva, Veronika; Bjerkstig, Göran; Örtorp, Anders

2017-01-01

Objectives The aim of this retrospective study was to evaluate the three-year clinical outcome for ceramic-veneered zirconia fixed dental prostheses (FDPs). Methods All patients who were treated with ceramic-veneered zirconia FDPs, in three private practices in Sweden, during the period June 2003 to April 2007 were included. Case records from 151 patients, treated with a total of 184 zirconia FDPs (692 units), were analysed for clinical data. All complications noted in the charts were registered and compared to definitions for success and survival and statistical analysis was performed using the Kaplan-Meier method and a Cox regression model. Results In total, 32 FDPs in 31 patients experienced some type of complication (17.4% of FDPs, 20.5% of patients). Core fractures occurred in two (1.1%) FDPs. Two (1.1%) FDPs or 0.6% of units showed adhesive veneer fractures. Cohesive veneer fractures occurred in 10 (5.4%) FDPs (1.6% of units). The three-year cumulative success and survival rates (CSR) were 82.3% and 95.2%, respectively. Conclusions Ceramic-veneered zirconia is a promising alternative to metal-ceramic FDPs, even in the posterior area. However, the higher survival rate of metal-ceramic FDPs should be noted and both dentists and patients must be aware of the risks of complications. PMID:28713427

Lower limb joint work and joint work contribution during downhill and uphill walking at different inclinations.

PubMed

Alexander, Nathalie; Strutzenberger, Gerda; Ameshofer, Lisa Maria; Schwameder, Hermann

2017-08-16

Work performance and individual joint contribution to total work are important information for creating training protocols, but were not assessed so far for sloped walking. Therefore, the purpose of this study was to analyze lower limb joint work and joint contribution of the hip, knee and ankle to total lower limb work during sloped walking in a healthy population. Eighteen male participants (27.0±4.7yrs, 1.80±0.05m, 74.5±8.2kg) walked on an instrumented ramp at inclination angles of 0°, ±6°, ±12° and ±18° at 1.1m/s. Kinematic and kinetic data were captured using a motion-capture system (Vicon) and two force plates (AMTI). Joint power curves, joint work (positive, negative, absolute) and each joint's contribution to total lower limb work were analyzed throughout the stance phase using an ANOVA with repeated measures. With increasing inclination positive joint work increased for the ankle and hip joint and in total during uphill walking. Negative joint work increased for each joint and in total work during downhill walking. Absolute work was increased during both uphill (all joints) and downhill (ankle & knee) walking. Knee joint contribution to total negative and absolute work increased during downhill walking while hip and ankle contributions decreased. This study identified, that, when switching from level to a 6° and from 6° to a 12° inclination the gain of individual joint work is more pronounced compared to switching from 12° to an 18° inclination. The results might be used for training recommendations and specific training intervention with respect to sloped walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of lateralized design on muscle and joint reaction forces for reverse shoulder arthroplasty.

PubMed

Liou, William; Yang, Yang; Petersen-Fitts, Graysen R; Lombardo, Daniel J; Stine, Sasha; Sabesan, Vani J

2017-04-01

Manufacturers of reverse shoulder arthroplasty (RSA) implants have recently designed innovative implants to optimize performance in rotator cuff-deficient shoulders. These advancements are not without tradeoffs and can have negative biomechanical effects. The objective of this study was to develop an integrated finite element analysis-kinematic model to compare the muscle forces and joint reaction forces (JRFs) of 3 different RSA designs. A kinematic model of a normal shoulder joint was adapted from the Delft model and integrated with the well-validated OpenSim shoulder model. Static optimizations then allowed for calculation of the individual muscle forces, moment arms, and JRFs relative to net joint moments. Three-dimensional computer models of 3 RSA designs-humeral lateralized design (HLD), glenoid lateralized design, and Grammont design-were integrated, and parametric studies were performed. Overall, there were decreases in deltoid and rotator cuff muscle forces for all 3 RSA designs. These decreases were greatest in the middle deltoid of the HLD model for abduction and flexion and in the rotator cuff muscles under both internal rotation and external rotation. The JRFs in abduction and flexion decreased similarly for all RSA designs compared with the normal shoulder model, with the greatest decrease seen in the HLD model. These findings demonstrate that the design characteristics implicit in these modified RSA prostheses result in mechanical differences most prominently seen in the deltoid muscle and overall JRFs. Further research using this novel integrated model can help guide continued optimization of RSA design and clinical outcomes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Effect of carbon ion implantation on the tribology of metal-on-metal bearings for artificial joints.

PubMed

Koseki, Hironobu; Tomita, Masato; Yonekura, Akihiko; Higuchi, Takashi; Sunagawa, Sinya; Baba, Koumei; Osaki, Makoto

2017-01-01

Metal-on-metal (MoM) bearings have become popular due to a major advantage over metal-on-polymer bearings for total hip arthroplasty in that the larger femoral head and hydrodynamic lubrication of the former reduce the rate of wear. However, concerns remain regarding adverse reactions to metal debris including metallosis caused by metal wear generated at the taper-head interface and another modular junction. Our group has hypothesized that carbon ion implantation (CII) may improve metal wear properties. The purpose of this study was to investigate the wear properties and friction coefficients of CII surfaces with an aim to ultimately apply these surfaces to MoM bearings in artificial joints. CII was applied to cobalt-chromium-molybdenum (Co-Cr-Mo) alloy substrates by plasma source ion implantation. The substrates were characterized using scanning electron microscopy and a 3D measuring laser microscope. Sliding contact tests were performed with a simple geometry pin-on-plate wear tester at a load of 2.5 N, a calculated contact pressure of 38.5 MPa (max: 57.8 MPa), a reciprocating velocity of 30 mm/s, a stroke length of 60 mm, and a reciprocating cycle count of 172,800 cycles. The surfaces of the CII substrates were generally featureless with a smooth surface topography at the same level as untreated Co-Cr-Mo alloy. Compared to the untreated Co-Cr-Mo alloy, the CII-treated bearings had lower friction coefficients, higher resistance to catastrophic damage, and prevented the adhesion of wear debris. The results of this study suggest that the CII surface stabilizes the wear status due to the low friction coefficient and low infiltration of partner materials, and these properties also prevent the adhesion of wear debris and inhibit excessive wear. Carbon is considered to be biologically inert; therefore, CII is anticipated to be applicable to the bearing surfaces of MoM prostheses.

Effect of carbon ion implantation on the tribology of metal-on-metal bearings for artificial joints

PubMed Central

Koseki, Hironobu; Tomita, Masato; Yonekura, Akihiko; Higuchi, Takashi; Sunagawa, Sinya; Baba, Koumei; Osaki, Makoto

2017-01-01

Metal-on-metal (MoM) bearings have become popular due to a major advantage over metal-on-polymer bearings for total hip arthroplasty in that the larger femoral head and hydrodynamic lubrication of the former reduce the rate of wear. However, concerns remain regarding adverse reactions to metal debris including metallosis caused by metal wear generated at the taper-head interface and another modular junction. Our group has hypothesized that carbon ion implantation (CII) may improve metal wear properties. The purpose of this study was to investigate the wear properties and friction coefficients of CII surfaces with an aim to ultimately apply these surfaces to MoM bearings in artificial joints. CII was applied to cobalt-chromium-molybdenum (Co-Cr-Mo) alloy substrates by plasma source ion implantation. The substrates were characterized using scanning electron microscopy and a 3D measuring laser microscope. Sliding contact tests were performed with a simple geometry pin-on-plate wear tester at a load of 2.5 N, a calculated contact pressure of 38.5 MPa (max: 57.8 MPa), a reciprocating velocity of 30 mm/s, a stroke length of 60 mm, and a reciprocating cycle count of 172,800 cycles. The surfaces of the CII substrates were generally featureless with a smooth surface topography at the same level as untreated Co-Cr-Mo alloy. Compared to the untreated Co-Cr-Mo alloy, the CII-treated bearings had lower friction coefficients, higher resistance to catastrophic damage, and prevented the adhesion of wear debris. The results of this study suggest that the CII surface stabilizes the wear status due to the low friction coefficient and low infiltration of partner materials, and these properties also prevent the adhesion of wear debris and inhibit excessive wear. Carbon is considered to be biologically inert; therefore, CII is anticipated to be applicable to the bearing surfaces of MoM prostheses. PMID:28615939

Study of the effect of the silver content on the structural and mechanical behavior of Ag-ZrCN coatings for orthopedic prostheses.

PubMed

Ferreri, I; Lopes, V; Calderon V, S; Tavares, C J; Cavaleiro, A; Carvalho, S

2014-09-01

With the increase of elderly population and health problems that are arising nowadays, hip joint prostheses are being widely used. However, it is estimated that 20% of hip replacement surgeries simply fails after few years, mainly due to wear fatigue. Bearing this in mind, this work reports on the development of new coatings that are able to sustain long and innocuous life inside the patient, which will confer to the usual biomaterials improved physical, mechanical and tribological properties. In particular, the development of multifunctional coatings based on Ag-ZrCN, prepared by DC reactive magnetron sputtering using two targets, Zr and a modified Zr target, in an Ar+C2H2+N2 atmosphere. Silver pellets were placed in the erosion area of the alloyed Zr target in order to obtain a silver content up to 8 at.%. The structural results obtained by x-ray diffraction show that the coatings crystallize in a NaCl crystal structure typical of ZrC1-xNx. The increase of Ag content promoted the formation of an additional a-CNx amorphous phase, besides a silver crystalline phase. Hardness is decreasing, as increasing silver content. Despite the low thicknesses, adhesion values (LC3) can be considered as good. Dynamic fatigue results suggest that these coatings system can be a real asset in terms of mechanical properties, by improving the performance of usual Stainless Steel 316 L biomaterials. Copyright © 2014 Elsevier B.V. All rights reserved.

Clinical outcomes of Kyocera Modular Limb Salvage system after resection of bone sarcoma of the distal part of the femur: the Japanese Musculoskeletal Oncology Group study.

PubMed

Nakamura, Tomoki; Matsumine, Akihiko; Uchida, Atsumasa; Kawai, Akira; Nishida, Yoshihiro; Kunisada, Toshiyuki; Araki, Nobuhito; Sugiura, Hideshi; Tomita, Masato; Yokouchi, Masahiro; Ueda, Takafumi; Sudo, Akihiro

2014-04-01

The Japanese Musculoskeletal Oncology Group have developed an original prosthesis called the Kyocera Modular Limb Salvage system (KMLS system). This prosthesis has a semi-rotating hinge joint and is particularly designed for people with an Asian body type. The metallic parts of the prosthesis are made entirely of titanium alloy. The purpose of this study is to evaluate the clinical outcomes of treatment using this system following tumour resection of primary bone sarcoma of the distal femur. Between 2002 and 2010, 82 patients with primary bone sarcomas of the distal femur were treated. Seventeen patients underwent stem cementation, while 65 patients were treated with cementless prostheses. The mean follow-up period after surgery was 61 months. Complications were observed in 28 of the 82 patients. Forty-one complications occurred in these 28 patients. Thirteen prostheses (16%) required revision surgery due to complications, including five cases of stem breakage, three deep infections, three cases of aseptic loosening, one case of displacement of the shaft cap and one case of breakage of the tibial tray. The five-year overall prosthetic survival rate was 80.0%. Four of the 82 patients underwent subsequent amputation due to local recurrence. The five-year limb salvage rate was 94.5%. The mean function score according to the scoring system of the Musculoskeletal Tumour Society was 21.8 points (72.5%). Although further follow-up is required to determine the performance, this prosthesis is considered to be satisfactory for reconstruction of the distal femur after resection of bone sarcoma.

Reduction of metal artifacts from alloy hip prostheses in computer tomography.

PubMed

Wang, Fengdan; Xue, Huadan; Yang, Xianda; Han, Wei; Qi, Bing; Fan, Yu; Qian, Wenwei; Wu, Zhihong; Zhang, Yan; Jin, Zhengyu

2014-01-01

The objective of this study was to evaluate the feasibility of reducing artifacts from large metal implants with gemstone spectral imaging (GSI) and metal artifact reduction software (MARS). Twenty-three in-vivo cobalt-chromium-molybdenum alloy total hip prostheses were prospectively scanned by fast kV-switching GSI between 80 and 140 kVp. The computed tomography images were reconstructed with monochromatic energy and with/without MARS. Both subjective and objective measurements were performed to assess the severity of metal artifacts. Increasing photon energy was associated with reduced metal artifacts in GSI images (P < 0.001). Combination of GSI with MARS further diminished the metal artifacts (P < 0.001). Artifact reduction at 3 anatomical levels (femoral head, neck, and shaft) were evaluated, with data showing that GSI and MARS could reduce metal artifacts at all 3 levels (P = 0.011, P < 0.001, and P = 0.003, respectively). Nevertheless, in certain cases, GSI without MARS produced more realistic images for the clinical situation. Proper usage of GSI with/without MARS could reduce the computed tomography artifacts of large metal parts and improve the radiological evaluation of postarthroplasty patients.

Differential effects of speech prostheses in glossectomized patients.

PubMed

Leonard, R J; Gillis, R

1990-12-01

Five patients representing different categories of glossal resection were fitted with prostheses specifically designed to improve speech. Speech recordings made for subjects with and without their prostheses were subjected to a variety of analyses. Prosthetic influence on listeners' judgments of severity level/intelligibility, number of consonants in error, and on the acoustic measure F2 range of vowels was evaluated. Findings indicated that all subjects demonstrated improvement on the speech measures. However, the extent of improvement on each measure varied across speakers and resection categories. Implications of the findings for prosthetic speech rehabilitation in this population are discussed.

Fabrication of a new silicone auricular prosthesis without removing the existing metallic framework.

PubMed

Goveas, Reiyal; Shrestha, Binit; Srithavaj, M L Theerathavaj; Thaworanunta, Sita

2014-12-01

Silicone prostheses require constant repair and refabrication. Auricular prostheses retained with implants have better retention than adhesive-retained prostheses. However, refabrication is complicated if the patient is unwilling to surrender the metallic framework attached to the implants and revert to the use of adhesives. This article describes a technique by which the metal framework of the existing prosthesis need not be removed, thereby improving the patient's quality of life until the new prosthesis is delivered. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Re-operation for aortic and mitral prosthetic dysfunctions.

PubMed

Kaul, T K; Sastry, M R; Mercer, J L; Meade, J B

1985-01-01

The overall incidence of re-operation and prosthetic valve endocarditis was low in the present series as mechanical prostheses were used predominantly. The prosthetic dysfunctions were less frequent following the primary implantation with Bjork Shiley prostheses, but high operative risk was associated with the clotted Bjork Shiley prostheses. We also had unusual experience of strut fracture and sticking of Bjork Shiley discs in the closed position in both aortic and mitral positions. The early deaths were nil since the use of cardioplegic protection. Intra-operative bleeding due to adhesions can be minimised by using synthetic or heterologous pericardium during the primary operation.

Design features of implants for direct skeletal attachment of limb prostheses

PubMed Central

Pitkin, M.

2013-01-01

In direct skeletal attachment (DSA) of limb prostheses, a construct is implanted into an amputee’s residuum bone and protrudes out of the residuum’s skin. This technology represents an alternative to traditional suspension of prostheses via various socket systems, with clear indications when the sockets cannot be properly fitted. Contemporary DSA was invented in the 1990s, and several implant systems have been introduced since then. The current review is intended to compare the design features of implants for DSA whose use in humans or in animal studies has been reported in the literature. PMID:23554122

Intensity-Modulated Radiation Therapy with Noncoplanar Beams for Treatment of Prostate Cancer in Patients with Bilateral Hip Prosthesis-A Case Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, Chris; Cheung, Rex Min; Kudchadker, Rajat J.

2010-07-01

Megavoltage photon intensity-modulated radiation therapy (IMRT) is typically used in the treatment of prostate cancer at our institution. Approximately 1% to 2% of patients with prostate cancer have hip prostheses. The presence of the prosthesis usually complicates the planning process because of dose perturbation around the prosthesis, radiation attenuation through the prosthesis, and the introduction of computed tomography artifacts in the planning volume. In addition, hip prostheses are typically made of materials of high atomic number, which add uncertainty to the dosimetry of the prostate and critical organs in the planning volume. When the prosthesis is bilateral, treatment planning ismore » further complicated because only a limited number of beam angles can be used to avoid the prostheses. In this case study, we will report the observed advantages of using noncoplanar beams in the delivery of IMRT to a prostate cancer patient with bilateral hip prostheses. The treatment was planned for 75.6 Gy using a 7-field coplanar approach and a noncoplanar arrangement, with all fields avoiding entrance though the prostheses. Our results indicate that, compared with the coplanar plan, the noncoplanar plan delivers the prescribed dose to the target with a slightly better conformality and sparing of rectal tissue versus the coplanar plan.« less

Soldering in prosthodontics--an overview, part I.

PubMed

Byrne, Gerard

2011-04-01

The fit of fixed multiunit dental prostheses (FDP), traditionally termed fixed partial dentures (FPDs), is an ongoing problem. Poorly fitting restorations may hasten mechanical failure, due to abutment caries or screw failure. Soldering and welding play an important role in trying to overcome misfit of fixed multiunit prostheses. The term FPD will be used to denote multiunit fixed dental prostheses in this review. This is the first of a series of articles that review the state of the art and science of soldering and welding in relation to the fit of cemented or screw-retained multiunit prostheses. A comprehensive archive of background information and scientific findings is presented. Texts in dental materials and prosthodontics were reviewed. Scientific data were drawn from the numerous laboratory studies up to and including 2009. The background, theory, terminology, and working principles, along with the applied research, are presented. This first article focuses on soldering principles and dimensional accuracy in soldering. There is some discussion and suggestions for future research and development. Soldering may improve dimensional accuracy or reduce the distortion of multiunit fixed prostheses. Many variables can affect the outcome in soldering technique. Research science has developed some helpful guidelines. Research projects are disconnected and limited in scope. © 2011 by The American College of Prosthodontists.

Fracture resistance and failure mode of posterior fixed dental prostheses fabricated with two zirconia CAD/CAM systems

PubMed Central

López-Suárez, Carlos; Gonzalo, Esther; Peláez, Jesús; Rodríguez, Verónica

2015-01-01

Background In recent years there has been an improvement of zirconia ceramic materials to replace posterior missing teeth. To date little in vitro studies has been carried out on the fracture resistance of zirconia veneered posterior fixed dental prostheses. This study investigated the fracture resistance and the failure mode of 3-unit zirconia-based posterior fixed dental prostheses fabricated with two CAD/CAM systems. Material and Methods Twenty posterior fixed dental prostheses were studied. Samples were randomly divided into two groups (n=10 each) according to the zirconia ceramic analyzed: Lava and Procera. Specimens were loaded until fracture under static load. Data were analyzed using Wilcoxon´s rank sum test and Wilcoxon´s signed-rank test (P<0.05). Results Partial fracture of the veneering porcelain occurred in 100% of the samples. Within each group, significant differences were shown between the veneering and the framework fracture resistance (P=0.002). The failure occurred in the connector cervical area in 80% of the cases. Conclusions All fracture load values of the zirconia frameworks could be considered clinically acceptable. The connector area is the weak point of the restorations. Key words:Fixed dental prostheses, zirconium-dioxide, zirconia, fracture resistance, failure mode. PMID:26155341

Evaluation of Osseous Integration of PVD-Silver-Coated Hip Prostheses in a Canine Model

PubMed Central

Hauschild, Gregor; Hardes, Jendrik; Gosheger, Georg; Blaske, Franziska; Wehe, Christoph; Karst, Uwe; Höll, Steffen

2015-01-01

Infection associated with biomaterials used for orthopedic prostheses remains a serious complication in orthopedics, especially tumor surgery. Silver-coating of orthopedic (mega)prostheses proved its efficiency in reducing infections but has been limited to surface areas exposed to soft tissues due to concerns of silver inhibiting osseous integration of cementless stems. To close this gap in the bactericidal capacity of silver-coated orthopedic prostheses extension of the silver-coating on surface areas intended for osseous integration seems to be inevitable. Our study reports about a PVD- (physical-vapor-deposition-) silver-coated cementless stem in a canine model for the first time and showed osseous integration of a silver-coated titanium surface in vivo. Radiological, histological, and biomechanical analysis revealed a stable osseous integration of four of nine stems implanted. Silver trace elemental concentrations in serum did not exceed 1.82 parts per billion (ppb) and can be considered as nontoxic. Changes in liver and kidney functions associated with the silver-coating could be excluded by blood chemistry analysis. This was in accordance with very limited metal displacement from coated surfaces observed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) 12 months after implantation. In conclusion our results represent a step towards complete bactericidal silver-coating of orthopedic prostheses. PMID:25695057

Periprosthetic bone loss in total hip arthroplasty. Polyethylene wear debris and the concept of the effective joint space.

PubMed

Schmalzried, T P; Jasty, M; Harris, W H

1992-07-01

Thirty-four hips in which there had been prosthetic replacement were selected for study because of the presence of linear (diffuse) or lytic (localized) areas of periprosthetic bone loss. In all hips, there was careful documentation of the anatomical location of the material that had been obtained for histological analysis, and the specific purpose of the removal of the tissue was for examination to determine the cause of the resorption of bone. Specimens from twenty-three hips were retrieved during an operation and from eleven hips, at autopsy. The area of bone loss was linear only in sixteen hips, lytic only in thirteen, and both linear and lytic in five. In all thirty-four hips, intracellular particulate debris was found in the macrophages that were present in the area of bone resorption. All thirty-four had intracellular particles of polyethylene, many of which were less than one micrometer in size. Thirty-one hips had extracellular particles of polyethylene as well. Twenty-two of the thirty-four hips had intracellular metallic debris; in ten, metallic debris was found extracellularly as well. Ten of the sixteen cemented specimens had intracellular and extracellular polymethylmethacrylate debris. In the mechanically stable prostheses--cemented and uncemented--polyethylene wear debris was identified in areas of bone resorption far from the articular surfaces. The number of macrophages in a microscopic field was directly related to the amount of particulate polyethylene debris that was visible by light microscopy. Although the gross radiographic appearances of linear bone loss and lytic bone loss were different, the histological appearance of the regions in which there was active bone resorption was similar. Regardless of the radiographic appearance and anatomical origin of the specimen, bone resorption was found to occur in association with macrophages that were laden with polyethylene debris. In general, the number of macrophages present had a direct relationship to the degree of bone resorption that was seen. We believe that these findings indicate that joint fluid penetrates far more extensively than previously thought, even in a well fixed component, along the interface between the prosthesis and bone and in the periprosthetic tissues; it is often more extensive than is shown by arthrography. We therefore suggest the concept of the effective joint space to include all periprosthetic regions that are accessible to joint fluid and thus accessible to particulate debris.(ABSTRACT TRUNCATED AT 400 WORDS)

The damping effect of cement as a potential mitigation factor of squeaking in ceramic-on-ceramic total hip arthroplasty.

PubMed

Burgo, F J; Mengelle, D E; Ozols, A; Fernandez, C; Autorino, C M

2016-11-01

Studies reporting specifically on squeaking in total hip arthroplasty have focused on cementless, and not on hybrid, fixation. We hypothesised that the cement mantle of the femur might have a damping effect on the sound transmitted through the metal stem. The objective of this study was to test the effect of cement on sound propagation along different stem designs and under different fixation conditions. An in vitro model for sound detection, composed of a mechanical suspension structure and a sound-registering electronic assembly, was designed. A pulse of sound in the audible range was propagated along bare stems and stems implanted in cadaveric bone femurs with and without cement. Two stems of different alloy and geometry were compared. The magnitudes of the maximum amplitudes of the bare stem were in the range of 10.8 V to 11.8 V, whereas the amplitudes for the same stems with a cement mantle in a cadaveric bone decreased to 0.3 V to 0.7 V, implying a pulse-attenuation efficiency of greater than 97%. The same magnitude is close to 40% when the comparison is made against stems implanted in cadaveric bone femurs without cement. The in vitro model presented here has shown that the cement had a remarkable effect on sound attenuation and a strong energy absorption in cement mantle and bone. The visco-elastic properties of cement can contribute to the dissipation of vibro-acoustic energy, thus preventing hip prostheses from squeaking. This could explain, at least in part, the lack of reports of squeaking when hybrid fixation is used.Cite this article: F. J. Burgo, D. E. Mengelle, A. Ozols, C. Fernandez, C. M. Autorino. The damping effect of cement as a potential mitigation factor of squeaking in ceramic-on-ceramic total hip arthroplasty. Bone Joint Res 2016;5:531-537. DOI: 10.1302/2046-3758.511.BJR-2016-0058.R1. © 2016 Burgo et al.

[A scanning electron microscopy study of the surface of porous-textured breast implants and their capsules. Description of the "velcro" effect of porous-textured breast prostheses].

PubMed

Danino, A; Rocher, F; Blanchet-Bardon, C; Revol, M; Servant, J M

2001-02-01

The efficacy of breast prosthesis texturing in the prevention of capsular contracture has been established for about 20 years. This successful procedure has led to the development and marketing of a number of different models. In the present study, four porous-textured breast prostheses have been examined: the Arion monoblock implant, the CUI (McGahn), the Biocell (Mcgahn), and the Sebbin LS21. Scanning electron microscopic (SEM) investigation of the implant surfaces of the different prostheses was carried out on new samples received from the manufacturers. During a prospective study on eight patients, capsule samples corresponding to the four above-mentioned prostheses were taken to determine whether a secondary intervention was necessary for correction of asymmetry or malpositioning. These samples were analyzed by SEM to investigate whether there could be a correlation between prosthesis texturing and the aspect of the corresponding capsules. Significant ultrastructural differences were found between the various prostheses examined: the results showed that only the CUI and Biocell prostheses presented a mirror image of the capsule texturing, with a correspondence between the depressions on the prosthesis and the contacts on the capsule. This finding seems to be linked to the existence of a critical size for the pores that constitute the implant surface. This observation led to the hypothesis of an adhesive "velcro" effect between the prosthesis and its capsule. Although the latter may not be directly linked to the prevention of capsular contracture it can, however, have a major effect on implant stabilization in cases of primary breast reconstruction and in possible secondary adjustments of asymmetry and malpositioning.

Mastication and oral health-related quality of life in removable denture wearers with Alzheimer disease.

PubMed

Campos, Camila H; Ribeiro, Giselle R; Rodrigues Garcia, Renata C M

2018-05-01

Alzheimer disease (AD) can affect masticatory function, affecting oral health-related quality of life (OHRQoL). Whether oral rehabilitation with conventional removable prostheses can restore masticatory function and improve OHRQoL in these individuals is unknown. The purpose of this clinical study was to evaluate the influence of oral rehabilitation with removable prostheses on masticatory efficiency and OHRQoL in elders with and without AD. Thirty-two elders with mild AD (n=16, mean age=76.7 ±6.3 years) or without AD (n=16, mean age=75.2 ±4.4 years) were recruited. All participants first underwent masticatory efficiency and OHRQoL evaluations, and 2 months after insertion of new removable prostheses, the variables were reassessed. Masticatory efficiency was determined using the sieving method, and OHRQoL was measured by applying the Geriatric Oral Health Assessment Index (GOHAI). The data from the baseline and after insertion of the new removable prostheses were compared by paired t test. Group differences at each time point were assessed by t test (α=.05). After insertion of the new removable prostheses, masticatory efficiency and OHRQoL improved in both the elders with AD and the control. At baseline, elders with AD had lower masticatory efficiency and higher OHRQoL than controls (P<.05). After removable prosthesis insertion, elders with AD continued to show lower masticatory efficiency values than controls, but their OHRQoL was similar. Oral rehabilitation with new removable prostheses improved the masticatory efficiency and OHRQoL of elders with and without AD, although masticatory efficiency did not reach control levels in elders with AD. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Characterisation of the responsive properties of two running-specific prosthetic models.

PubMed

Grobler, Lara; Ferreira, Suzanne; Vanwanseele, Benedicte; Terblanche, Elmarie E

2017-04-01

The need for information regarding running-specific prosthetic properties has previously been voiced. Such information is necessary to assist in athletes' prostheses selection. This study aimed to describe the characteristics of two commercially available running-specific prostheses. The running-specific prostheses were tested (in an experimental setup) without the external interference of athlete performance variations. Four stiffness categories of each running-specific prosthetic model (Xtend ™ and Xtreme ™ ) were tested at seven alignment setups and three drop masses (28, 38 and 48 kg). Results for peak ground reaction force (GRF peak ), contact time ( t c ), flight time ( t f ), reactive strength index (RSI) and maximal compression (Δ L) were determined during controlled dropping of running-specific prostheses onto a force platform with different masses attached to the experimental setup. No statistically significant differences were found between the different setups of the running-specific prostheses. Statistically significant differences were found between the two models for all outcome variables (GRF peak , Xtend > Xtreme; t c , Xtreme > Xtend; t f , Xtreme > Xtend; RSI, Xtend > Xtreme; Δ L, Xtreme > Xtend; p < 0.05). These findings suggest that the Xtreme stores more elastic energy than the Xtend, leading to a greater performance response. The specific responsive features of blades could guide sprint athletes in their choice of running-specific prostheses. Clinical relevance Insights into the running-specific prosthesis (RSP) properties and an understanding of its responsive characteristics have implications for athletes' prosthetic choice. Physiologically and metabolically, a short sprint event (i.e. 100 m) places different demands on the athlete than a long sprint event (i.e. 400 m), and the RSP should match these performance demands.

Occlusal contact of fixed implant prostheses using functional bite impression technique.

PubMed

Suzuki, Yasunori; Shimpo, Hidemasa; Ohkubo, Chikahiro

2015-02-01

Functional bite impression (FBI) has been described as a definitive impression made under occlusal force after functional generated path (FGP) recording. This study compared the accuracy of occlusal contact of implant-fixed prostheses using the FBI technique and the conventional impression technique. Twelve subjects, each missing a single premolar or molar, were selected for this study. The conditions of the occlusal contacts were identified by the modified transillumination method. The occlusal contact condition was determined by comparing the rate of change in the occlusal contact area of the implant-fixed prostheses and both adjacent teeth before and after occlusal adjustment. The rate of change in the occlusal contact area using the FBI technique was 96%, and the rate using the conventional technique was 54%. The occlusal contact of implant prostheses using the FBI technique revealed better accuracy than that of the conventional technique. Regarding the FBI technique, a precise and functional prosthesis could be produced by completing the maxillomandibular registration, impression, and FGP at the same time.

Clinical performance of removable dental prostheses in the moderately reduced dentition: a systematic literature review.

PubMed

Moldovan, Ovidiu; Rudolph, Heike; Luthardt, Ralph G

2016-09-01

Evidence-based therapeutic recommendations for removable dental prostheses are still lacking. The aim of the present study was a systematic review and meta-analysis of the survival rates of removable dentures in the moderately reduced dentition. In 2014, a systematic literature search in established medical databases (MEDLINE, EMBASE, BIOSIS, SciSearch, Cochrane, FIZ Technik Web) and a hand search of relevant dental journals were conducted. The search terms were relevant MeSH terms, free search terms, and combinations of the two. The search included RCTs, prospective and retrospective studies on survival rates of removable dental prostheses in the moderately reduced dentition with at least 15 participants, an observation period of at least 2 years, and a dropout rate of less than 25 %. The selection of relevant publications was carried out at the title, abstract, and full-text level by at least two of the authors involved. The publications included were tabulated and analyzed. Of the original 12,994 matches, 1923 were analyzed by title, 650 by abstract, and 111 according to the full text. The final review included 19 publications, of which 6 were multiple publications. Cast-metal framework dentures exhibited failure rates of between 33 and 50 % after 5 years. One study with a 25-year observation period reported failure rates of 50 %. Better results were obtained with proper pretreatment and a good recall scheme. Bilateral attachment prostheses showed failure rates of between 11 and 30 % after 5 years. Unilateral attachment prostheses showed failure rates of 75 % after 5 years. Double-crown prostheses dentures show failure rates of 0 to 21.7 % after 3 to 6 years. Heterogeneous study designs and data analyses rendered a meta-analysis impossible, so that an evaluation at the highest level of evidence could not be performed. Within the limitations of this study, it would be correct to state that removable dental prostheses, given suitable pretreatment and follow-up regimes, can provide satisfactory solutions. Based on only one paper, they revealed acceptable results even over a very long observation period (25 years).

In vitro comparative analysis of the fit of gold alloy or commercially pure titanium implant-supported prostheses before and after electroerosion.

PubMed

Sartori, Ivete Aparecida de Mattias; Ribeiro, Ricardo Faria; Francischone, Carlos Eduardo; de Mattos, Maria da Gloria Chiarello

2004-08-01

For implant-supported prostheses, passive fit is critical for the success of rehabilitation, especially when alternative materials are used. The purpose of this study was to compare interfacial fit of implant-supported prostheses cast in titanium to those cast in gold alloy. Five 3-unit fixed partial dentures were fabricated in gold alloy (Degudent U) as 1-piece castings, and 5 others were similarly cast in commercially pure titanium (Grade 1). The interfacial gaps between the prostheses and the abutments were evaluated with an optical microscope, before and after electroerosion. Readings were made with both screws tightened (10 N.cm torque), and with only 1 side tightened, so as to also evaluate the passive fit of the prostheses. Data were compared statistically by 2-way analysis of variance and the post hoc Tukey multiple range test (alpha=.05). Before electroerosion, the interfacial gaps for the 1-piece prostheses were significantly smaller (P<.001) in the gold alloy group when the screws were tightened (Au=12.6 +/- 3.0 microm, compared to Ti=30.1 +/- 6.4 microm). When the side opposite the tightened side was analyzed, there was no significant difference between the gold alloy and titanium groups (Au=69.2 +/- 24.9 microm and Ti=94.2 +/- 39.6 microm). The electroerosion procedure significantly (P<.001) reduced the gaps at the interfaces for both groups under all conditions. Comparison between groups after electroerosion did not present significant differences when the side opposite the tightened side was analyzed, but the gold alloy group showed better fit when the tightened side was analyzed (12.8 +/- 1.4 microm for gold alloy; 29.6 +/- 4.4 microm for titanium) and when both screws were tightened (5.4 +/- 2.3 microm for gold alloy; 16.1 +/- 5.5 microm for titanium). Cast titanium prostheses, despite showing larger interfacial gaps between the prosthesis and abutment than those obtained with gold alloy, had improved fit after being subjected to electroerosion.

Effect of joint design and welding type on the flexural strength and weld penetration of Ti-6Al-4V alloy bars.

PubMed

Simamoto Júnior, Paulo Cézar; Resende Novais, Veridiana; Rodrigues Machado, Asbel; Soares, Carlos José; Araújo Raposo, Luís Henrique

2015-05-01

Framework longevity is a key factor for the success of complete-arch prostheses and commonly depends on the welding methods. However, no consensus has been reached on the joint design and welding type for improving framework resistance. The purpose of this study was to assess the effect of different joint designs and welding methods with tungsten inert gas (TIG) or laser to join titanium alloy bars (Ti-6Al-4V). Seventy titanium alloy bar specimens were prepared (3.18 mm in diameter × 40.0 mm in length) and divided into 7 groups (n=10): the C-control group consisting of intact specimens without joints and the remaining 6 groups consisting of specimens sectioned perpendicular to the long-axis and rejoined using an I-, X30-, or X45-shaped joint design with TIG welding (TI, TX30, and TX45) or laser welding (LI, LX30, and LX45). The specimens were tested with 3-point bending. The fracture surfaces were first evaluated with stereomicroscopy to measure the weld penetration area and then analyzed with scanning electron microscopy (SEM). The data were statistically analyzed with 2-way ANOVA and the Tukey post hoc test, 1-way ANOVA and the Dunnett test, and the Pearson correlation test (α=.05). Specimens from the X30 and X45 groups showed higher flexural strength (P<.05) and welded area (P<.05) than specimens from the I groups, regardless of the welding type. TIG welded groups showed significantly higher flexural strength than the laser groups (P<.05), regardless of the joint design. TIG welding also resulted in higher welded areas than laser welding for the I-shaped specimens. No significant differences were found for the weld penetration area in the X45 group, either for laser or TIG welding. SEM analysis showed more pores at the fracture surfaces of the laser specimens. Fracture surfaces indicative of regions of increased ductility were detected for the TIG specimens. TIG welding resulted in higher flexural strength for the joined titanium specimens than laser welding. For both welding methods, X30- and X45-shaped joint designs resulted in higher flexural strength and welding penetration than the I-shaped joint design. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Recent advances in bioelectric prostheses

PubMed Central

Pasquina, Paul F.; Perry, Briana N.; Miller, Matthew E.; Ling, Geoffrey S.F.; Tsao, Jack W.

2015-01-01

Summary Worldwide prevalence of amputation has created an increasing demand for improved upper and lower extremity prostheses. Current prosthetics are often uncomfortable and difficult to control and provide limited functional restoration. Moreover, the inability to normalize anthropomorphic biomechanics with a prosthesis increases one's risk of developing long-term health risks such as arthritis, skin breakdown, and pain. Recent advances in bionic prosthetic development hold great promise for rehabilitation and improving quality of life with limb loss. This brief review discusses the current state of advanced prostheses, the integration of robotics in the care of individuals with major limb amputation, and some innovative surgical techniques that are being explored for clinical feasibility. PMID:29443190

Processing of hydroxylapatite coatings on titanium alloy bone prostheses

DOEpatents

Nastasi, M.A.; Levine, T.E.; Mayer, J.W.; Pizziconi, V.B.

1998-10-06

Processing of hydroxylapatite sol-gel films on titanium alloy bone prostheses. A method utilizing non-line-of-sight ion beam implantation and/or rapid thermal processing to provide improved bonding of layers of hydroxylapatite to titanium alloy substrates while encouraging bone ingrowth into the hydroxylapatite layers located away from the substrate, is described for the fabrication of prostheses. The first layer of hydroxylapatite is mixed into the substrate by the ions or rapidly thermally annealed, while subsequent layers are heat treated or densified using ion implantation to form layers of decreasing density and larger crystallization, with the outermost layers being suitable for bone ingrowth.

Processing of hydroxylapatite coatings on titanium alloy bone prostheses

DOEpatents

Nastasi, Michael A.; Levine, Timothy E.; Mayer, James W.; Pizziconi, Vincent B.

1998-01-01

Processing of hydroxylapatite sol-gel films on titanium alloy bone prostheses. A method utilizing non-line-of-sight ion beam implantation and/or rapid thermal processing to provide improved bonding of layers of hydroxylapatite to titanium alloy substrates while encouraging bone ingrowth into the hydroxylapatite layers located away from the substrate, is described for the fabrication of prostheses. The first layer of hydroxylapatite is mixed into the substrate by the ions or rapidly thermally annealed, while subsequent layers are heat treated or densified using ion implantation to form layers of decreasing density and larger crystallization, with the outermost layers being suitable for bone ingrowth.

The Role of Bariatric Surgery in the Obese Total Joint Arthroplasty Patient.

PubMed

Hooper, Jessica M; Deshmukh, Ajit J; Schwarzkopf, Ran

2018-07-01

Although bariatric surgery is a proven means of weight loss and treatment of obesity-related comorbidities in morbidly obese patients, it is not yet clear how it affects outcomes after total joint arthroplasty in this high-risk patient population. This article explores the effects of obesity and bariatric surgery on osteoarthritis and total joint arthroplasty, and also discusses the financial and ethical implications of use of bariatric surgery for risk reduction before total joint arthroplasty. Copyright © 2018 Elsevier Inc. All rights reserved.

An electromechanical swing-phase-controlled prosthetic knee joint for conversion of physiological energy to electrical energy: feasibility study.

PubMed

Andrysek, Jan; Chau, Gilbert

2007-12-01

Microprocessor-controlled prostheses facilitate a more natural and efficient gait for individuals with above-knee amputations by continually adjusting the level of swing-phase damping. One caveat associated with these technologies is that the user must charge the onboard batteries on a daily basis. It is, therefore, the aim of this study to examine the feasibility of using an electromechanical system to provide prosthetic swing-phase damping and, concomitantly, the function of converting physiological energy that is normally dissipated during the swing phase, to electrical energy. Gait data from a single subject and data from a kinematic simulator were used to develop an empirical model. The findings in this study indicate that an electromagnetic system has appropriate characteristics for use in swing-phase control and also has the potential to recover energy under particular conditions.

Energetic Passivity of the Human Ankle Joint.

PubMed

Lee, Hyunglae; Hogan, Neville

2016-12-01

Understanding the passive or nonpassive behavior of the neuromuscular system is important to design and control robots that physically interact with humans, since it provides quantitative information to secure coupled stability while maximizing performance. This has become more important than ever apace with the increasing demand for robotic technologies in neurorehabilitation. This paper presents a quantitative characterization of passive and nonpassive behavior of the ankle of young healthy subjects, which provides a baseline for future studies in persons with neurological impairments and information for future developments of rehabilitation robots, such as exoskeletal devices and powered prostheses. Measurements using a wearable ankle robot actuating 2 degrees-of-freedom of the ankle combined with curl analysis and passivity analysis enabled characterization of both quasi-static and steady-state dynamic behavior of the ankle, unavailable from single DOF studies. Despite active neuromuscular control over a wide range of muscle activation, in young healthy subjects passive or dissipative ankle behavior predominated.

Analysis of the times involved in processing and communication in a lower limb simulation system controlled by SEMG

NASA Astrophysics Data System (ADS)

Profumieri, A.; Bonell, C.; Catalfamo, P.; Cherniz, A.

2016-04-01

Virtual reality has been proposed for different applications, including the evaluation of new control strategies and training protocols for upper limb prostheses and for the study of new rehabilitation programs. In this study, a lower limb simulation environment commanded by surface electromyography signals is evaluated. The time delays generated by the acquisition and processing stages for the signals that would command the knee joint, were measured and different acquisition windows were analysed. The subjective perception of the quality of simulation was also evaluated when extra delays were added to the process. The results showed that the acquisition window is responsible for the longest delay. Also, the basic implemented processes allowed for the acquisition of three signal channels for commanding the simulation. Finally, the communication between different applications is arguably efficient, although it depends on the amount of data to be sent.

Major trends in mobility technology research and development: overview of the results of the NSF-WTEC European study.

PubMed

Reinkensmeyer, David J; Bonato, Paolo; Boninger, Michael L; Chan, Leighton; Cowan, Rachel E; Fregly, Benjamin J; Rodgers, Mary M

2012-04-20

Mobility technologies, including wheelchairs, prostheses, joint replacements, assistive devices, and therapeutic exercise equipment help millions of people participate in desired life activities. Yet, these technologies are not yet fully transformative because many desired activities cannot be pursued or are difficult to pursue for the millions of individuals with mobility related impairments. This WTEC study, initiated and funded by the National Science Foundation, was designed to gather information on European innovations and trends in technology that might lead to greater mobility for a wider range of people. What might these transformative technologies be and how might they arise? Based on visits to leading mobility technology research labs in western Europe, the WTEC panel identified eight major trends in mobility technology research. This commentary summarizes these trends, which are then described in detail in companion papers appearing in this special issue.

Major trends in mobility technology research and development: Overview of the results of the NSF-WTEC European study

PubMed Central

2012-01-01

Mobility technologies, including wheelchairs, prostheses, joint replacements, assistive devices, and therapeutic exercise equipment help millions of people participate in desired life activities. Yet, these technologies are not yet fully transformative because many desired activities cannot be pursued or are difficult to pursue for the millions of individuals with mobility related impairments. This WTEC study, initiated and funded by the National Science Foundation, was designed to gather information on European innovations and trends in technology that might lead to greater mobility for a wider range of people. What might these transformative technologies be and how might they arise? Based on visits to leading mobility technology research labs in western Europe, the WTEC panel identified eight major trends in mobility technology research. This commentary summarizes these trends, which are then described in detail in companion papers appearing in this special issue. PMID:22520596

New Ti-Alloys and Surface Modifications to Improve the Mechanical Properties and the Biological Response to Orthopedic and Dental Implants: A Review

PubMed Central

Kirmanidou, Yvoni; Sidira, Margarita; Drosou, Maria-Eleni; Bennani, Vincent; Bakopoulou, Athina; Tsouknidas, Alexander; Michailidis, Nikolaos; Michalakis, Konstantinos

2016-01-01

Titanium implants are widely used in the orthopedic and dentistry fields for many decades, for joint arthroplasties, spinal and maxillofacial reconstructions, and dental prostheses. However, despite the quite satisfactory survival rates failures still exist. New Ti-alloys and surface treatments have been developed, in an attempt to overcome those failures. This review provides information about new Ti-alloys that provide better mechanical properties to the implants, such as superelasticity, mechanical strength, and corrosion resistance. Furthermore, in vitro and in vivo studies, which investigate the biocompatibility and cytotoxicity of these new biomaterials, are introduced. In addition, data regarding the bioactivity of new surface treatments and surface topographies on Ti-implants is provided. The aim of this paper is to discuss the current trends, advantages, and disadvantages of new titanium-based biomaterials, fabricated to enhance the quality of life of many patients around the world. PMID:26885506

28 CFR 43.1 - Administrative determination and assertion of claims.

Code of Federal Regulations, 2010 CFR

2010-07-01

... for the furnishing of hospital, medical, surgical or dental care and treatment (including prostheses... dental care and treatment was or will be furnished for an injury or disease caused under circumstances..., medical, surgical, or dental care and treatment (including prostheses and medical appliances) furnished by...

Framework design and pontics of fiber-reinforced composite fixed dental prostheses - An overview.

PubMed

Perea-Lowery, Leila; Vallittu, Pekka K

2018-05-11

Fiber-reinforced composite (FRC) fixed dental prostheses (FDPs) have shown good performance in clinical applications due to their good mechanical properties and minimally invasive approach. However, typical failure patterns of FRC FDPs are often localized at the pontic site. That reflects the structural considerations at the framework and pontic location that need to be examined when creating these kinds of prostheses. Peer-reviewed articles and other scientific literature were reviewed for providing up-to-date information on how pontics of FRC FDPs can be made. A thorough literature search was done using PubMed and Google Scholar. Two individuals did an assessment of the articles in order to include those related to pontics and framework design of FRC FDPs. The search terms used were "fiber-reinforced dental prosthesis" and "Pontics of fiber-reinforced dental prosthesis". These findings indicate that a cross-sectional fiber design, substructure and thicker pontics made of a variety of materials might reduce failures at the pontic site. The thickness of pontics of FRC FDPs interrelated with the vertical positioning of the FRC framework influences the load-bearing capacities of prostheses of these kinds. The understanding of the factors involved in the fabrication of pontics of FRC FDPs may overcome the drawbacks identified in these prostheses, thus extending their longevity. Copyright © 2018 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Three-phase bone scan and indium white blood cell scintigraphy following porous coated hip arthroplasty: A prospective study of the prosthetic tip

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oswald, S.G.; Van Nostrand, D.; Savory, C.G.

1989-08-01

Although few reports address the use of three-phase bone scanning (TPBS) and {sup 111}In-labeled white blood cell (In-WBC) scintigraphy in hip arthroplasty utilizing a porous coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen in the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and In-WBC at approximately 7 days, and at 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the prosthetic tip. Only one of 136more » flow studies were abnormal and only two of 136 blood-pool images demonstrated focally increased activity. All 25 prostheses (120 of 143 scans) demonstrated increased uptake on the bone phase images. The area about the tip was divided into three segments; increased uptake at 24 mo was noted in the medial, distal, and lateral segments in 16%, 72%, and 56% of prostheses, respectively. Twenty of 25 prostheses (82 of 142 scans) showed uptake on In-WBC scintigraphy, being noted in 48% of prostheses at 24 mo. We conclude that scintigraphic patterns in the uncomplicated patient with a porous coated prosthesis appear to differ from patterns described in cemented prostheses.« less

Experimental and computational investigation of Morse taper conometric system reliability for the definition of fixed connections between dental implants and prostheses.

PubMed

Bressan, Eriberto; Lops, Diego; Tomasi, Cristiano; Ricci, Sara; Stocchero, Michele; Carniel, Emanuele Luigi

2014-07-01

Nowadays, dental implantology is a reliable technique for treatment of partially and completely edentulous patients. The achievement of stable dentition is ensured by implant-supported fixed dental prostheses. Morse taper conometric system may provide fixed retention between implants and dental prostheses. The aim of this study was to investigate retentive performance and mechanical strength of a Morse taper conometric system used as implant-supported fixed dental prostheses retention. Experimental and finite element investigations were performed. Experimental tests were achieved on a specific abutment-coping system, accounting for both cemented and non-cemented situations. The results from the experimental activities were processed to identify the mechanical behavior of the coping-abutment interface. Finally, the achieved information was applied to develop reliable finite element models of different abutment-coping systems. The analyses were developed accounting for different geometrical conformations of the abutment-coping system, such as different taper angle. The results showed that activation process, occurred through a suitable insertion force, could provide retentive performances equal to a cemented system without compromising the mechanical functionality of the system. These findings suggest that Morse taper conometrical system can provide a fixed connection between implants and dental prostheses if proper insertion force is applied. Activation process does not compromise the mechanical functionality of the system. © IMechE 2014.

The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses

PubMed Central

Bacchiocchi, Danilo

2017-01-01

Purpose To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses. Methods Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The “Ball Welding Bar” (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing. Results Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%. Conclusions The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338. PMID:28835752

Clinical experiences of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw: a 5-year follow-up study.

PubMed

Ortorp, A; Jemt, T

1999-01-01

Titanium frameworks have been used in the endentulous implant patient for the last 10 years. However, knowledge of titanium frameworks for the partially dentate patient is limited. To report the 5-year clinical performance of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw. A consecutive group of 383 partially edentulous patients were, on a routine basis, provided with fixed partial prostheses supported by Brånemark implants in the mandible or maxilla. Besides conventional frameworks in cast gold alloy, 58 patients were provided with titanium frameworks with three different veneering techniques, and clinical and radiographic 5-year data were collected for this group. The overall cumulative survival rate was 95.6% for titanium-framework prostheses and 93.6% for implants. Average bone loss during the follow-up period was 0.4 mm. The most common complications were minor veneering fractures. Loose and fractured implant screw components were fewer than 2%. An observation was that patients on medications for cardiovascular problems may lose more implants than others (p < .05). The clinical performance of prostheses with implant-supported laser-welded titanium frameworks was similar to that reported for conventional cast frames in partially edentulous jaws. Low-fusing porcelain veneers also showed clinical performance comparable to that reported for conventional porcelain-fused-to-metal techniques.

A first experience with digital complete overdentures.

PubMed

Bajunaid, Salwa Omar

2016-07-01

The development of computer-aided design/computer-aided manufacturing systems for dentistry in the 1980s resulted in the successful fabrication of crowns, fixed dental prostheses, and superstructures for both natural teeth and dental implants. Today, this technology is available for constructing digitally designed and milled, completely removable dental prostheses. The procedure uses clinical and laboratory protocols that allow fabrication of completely removable prostheses within two clinical appointments. The aim of this clinical report is to present the author's first experience with digital complete overdentures, the practicality of this technology, and patient feedback. Compared with conventional overdentures, the fit of the digital prostheses was improved because the cameo and flanges of the prostheses were nicely shaped and rolled, and this enhanced their stability and retention. Occlusion was also excellent. However, aesthetics in terms of the alignment, shape, and size of the maxillary overdenture teeth were inacceptable. Despite some of the drawbacks identified in our study, the use of removable digital dentures does provide excellent adaptation of the denture base and requires fewer clinic visits. We anticipate that the unsatisfactory aesthetic outcomes presented in this report can be corrected with more experience. We also believe that acquiring an in-house scanning machine would be beneficial. We highly recommend including this technique in dental school curriculums at both the undergraduate and graduate levels in order to keep students and residents up to date on the latest technology available.

Incidence and impact of prosthesis-patient mismatch after transcatheter aortic valve implantation.

PubMed

Bleiziffer, Sabine; Hettich, Ina; Hutter, Andrea; Wagner, Anke; Deutsch, Marcus-André; Piazza, Nicolo; Lange, Rüdiger

2013-05-01

The study aim was to investigate the incidence of patient-prosthesis mismatch (PPM) with new catheter valves, and its influence on the patients' clinical state. At present, few echocardiographic data are available on the incidence and impact of PPM with the CoreValve and Sapien prostheses for transcatheter aortic valve implantation (TAVI). The reliability of effective orifice area (EOA) measurements was assured by awaiting an interval of six months after TAVI. Of 256 survivors after TAVI, 149 complete echocardiographic data sets were available for the assessment of the indexed EOA (iEOA). In total, 106 CoreValve prostheses and 43 Sapien prostheses were implanted in this high-risk cohort (mean age 81 +/- 6 years, mean logistic EuroSCORE 20 +/- 13%). The overall incidence of PPM (iEOA < 0.85 cm2/m2) was 61%. Patients with a larger body surface area were more likely to develop PPM (p = 0.001), while the prosthesis type, native annulus diameter, preoperative EOA, gender and prosthesis size had no influence. The mean aortic gradient was significantly higher in patients with PPM. A reduction in the left ventricular end-diastolic diameter was seen in all patients, without significant differences between groups. There were no differences in postoperative NYHA class or self-assessed health state between patients with or without PPM. PPM was common after TAVI in the presented cohort, presumably because the native calcium masses narrow the outflow area available for blood flow. As expected for low gradients, there was no impairment of left ventricular dimension regression or clinical state of the patients, even if severe PPM was present. Based on the presented data, it is assumed that PPM might be less relevant in TAVI patients.

Effect of alignment changes on sagittal and coronal socket reaction moment interactions in transtibial prostheses.

PubMed

Kobayashi, Toshiki; Orendurff, Michael S; Zhang, Ming; Boone, David A

2013-04-26

Alignment is important for comfortable and stable gait of lower-limb prosthesis users. The magnitude of socket reaction moments in the multiple planes acting simultaneously upon the residual limb may be related to perception of comfort in individuals using prostheses through socket interface pressures. The aim of this study was to investigate the effect of prosthetic alignment changes on sagittal and coronal socket reaction moment interactions (moment-moment curves) and to characterize the curves in 11 individuals with transtibial amputation using novel moment-moment interaction parameters measured by plotting sagittal socket reaction moments versus coronal ones under various alignment conditions. A custom instrumented prosthesis alignment component was used to measure socket reaction moments during walking. Prosthetic alignment was tuned to a nominally aligned condition by a prosthetist, and from this position, angular (3° and 6° of flexion, extension, abduction or adduction of the socket) and translational (5mm and 10mm of anterior, posterior, medial or lateral translation of the socket) alignment changes were performed in either the sagittal or the coronal plane in a randomized manner. A total of 17 alignment conditions were tested. Coronal angulation and translation alignment changes demonstrated similar consistent changes in the moment-moment curves. Sagittal alignment changes demonstrated more complex changes compared to the coronal alignment changes. Effect of sagittal angulations and translations on the moment-moment curves was different during 2nd rocker (mid-stance) with extension malalignment appearing to cause medio-lateral instability. Presentation of coronal and sagittal socket reaction moment interactions may provide useful visual information for prosthetists to understand the biomechanical effects of malalignment of transtibial prostheses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Radiographic parameters improve lower extremity prosthetic alignment.

PubMed

Mooney, Ryan; Carry, Patrick; Wylie, Erin; Schultz, Abby; McNair, Bryan; Page, Carol; Biffl, Susan; Heare, Travis

2013-12-01

The goal of prosthetic fitting is to provide comfort and functionality to the patient. It is thought that incorporating the use of standing anterior-posterior long leg radiographs (LLR) into the fitting of lower extremity prostheses will provide an objective guide when making adjustments, and be a better assessment of alignment. This study compares prosthetic alignment before and after radiography-guided adjustments. This retrospective study was performed at a multidisciplinary amputee clinic on patients with congenital and/or acquired limb deficiencies. Their prosthetic alignment was evaluated by LLR and adjusted as needed. Satisfactory alignment was defined as a mechanical axis angular deviation of ≤1° and a leg length discrepancy of ≤10 mm. A total of 45 unique prostheses from 24 subjects (10 female and 14 male) were included. Post-adjustment radiographs were obtained from 29 prostheses. After the initial prosthetic fitting, the probability of a satisfactory fit was 20.0 % (95 % CI 10.9-34.9 %). Following the baseline adjustment, the probability of a satisfactory fit improved to 53.3 % (95 % CI 37.5-70.9 %). After adjustment number 4, the probability of a satisfactory fit further improved to 76.7 % (95 % CI 41.9-98.0 %). There were also significant improvements in distal offset distance (p = 0.0040) and leg length discrepancy (p = 0.0206). The distal offset distance decreased by an average of 10.7 mm (95 % CI 3.6-17.8), and leg length discrepancy decreased by an average of 3.0 mm (95 % CI 00.48-5.5). The addition of LLRs to existing fitting methods significantly improves prosthetic alignment and length.

The future of dental devices is digital.

PubMed

van Noort, Richard

2012-01-01

Major changes are taking place in dental laboratories as a result of new digital technologies. Our aim is to provide an overview of these changes. In this article the reader will be introduced to the range of layered fabrication technologies and suggestions are made how these might be used in dentistry. Key publications in English from the past two decades are surveyed. The first digital revolution took place many years ago now with the production of dental restorations such as veneers, inlays, crowns and bridges using dental CAD-CAM systems and new improved systems appear on the market with great rapidity. The reducing cost of processing power will ensure that these developments will continue as exemplified by the recent introduction of a new range of digital intra-oral scanners. With regard to the manufacture of prostheses this is currently dominated by subtractive machining technology but it is inevitable that the additive processing routes of layered fabrication, such as FDM, SLA, SLM and inkjet printing, will start to have an impact. In principle there is no reason why the technology cannot be extended to all aspects of production of dental prostheses and include customized implants, full denture construction and orthodontic appliances. In fact anything that you might expect a dental laboratory to produce can be done digitally and potentially more consistently, quicker and at a reduced cost. Dental device manufacturing will experience a second revolution when layered fabrication techniques reach the point of being able to produce high quality dental prostheses. The challenge for the dental materials research community is to marry the technology with materials that are suitable for use in dentistry. This can potentially take dental materials research in a totally different direction. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Dental implants as strategic supplementary abutments for implant-tooth-supported telescopic crown-retained maxillary dentures: a retrospective follow-up study for up to 9 years.

PubMed

Krennmair, Gerald; Krainhöfner, Martin; Waldenberger, Otmar; Piehslinger, Eva

2007-01-01

The aim of this retrospective study was to present the results of implants and natural teeth used as combined abutments to support maxillary telescopic prostheses. Between 1997 and 2004, 22 patients with residual maxillary teeth underwent prosthodontic rehabilitation with supplementary implant placement of implant-tooth-supported telescopic prostheses. A total of 60 supplementary implants (mean: 2.9 implants; SD: 1.6; range: 1 to 5 per patient) were placed in strategic position and connected with 48 natural abutment teeth (mean: 2.2 teeth; SD: 0.9; range: 1 to 4 per patient) using telescopic crowns. The follow-up registration included implant and natural tooth survival rates and peri-implant and periodontal parameters, along with prosthodontic maintenance. Natural tooth abutments were additionally followed to compare their periodontal parameters at baseline to the follow-up examination. After a mean of 38 months (12 to 108 months) no implants or natural tooth abutments were lost (survival rate: 100%). There was no fracture, endodontic treatment, loss, or intrusion of natural teeth used for telescopic abutments. Implant abutments showed high stability and excellent periimplant soft tissue conditions. Natural tooth abutments used for double crowns also showed uneventful progress. A low rate of prosthodontic maintenance was seen, with implant screw abutment loosening as the most severe complication (3 of 60 implants; 5%). On the basis of this retrospective clinical review, the following conclusions were drawn: (1) successful function over a prolonged period and a minor complication rate of implant-tooth-supported telescopic maxillary dentures may be anticipated, and (2) the great variety of treatment modalities offered by tooth-implant support for telescopic prostheses appears to be useful as a treatment option for the maxilla in elderly patients.

Evaluation of the efficacy of mandibular conventional and implant prostheses in a group of Turkish patients: a quality of life study.

PubMed

Cakir, Onur; Kazancioglu, Hakki Oguz; Celik, Gozde; Deger, Sabire; Ak, Gulsum

2014-07-01

The aim of this study was to compare the satisfaction and quality of life (QoL) in a group of patients using mandibular complete dentures, implant-retained overdentures, removable partial dentures (RPDs), or implant-supported fixed partial dentures (FPDs). A total of 116 patients (aged 36 to 81, mean age 58 ± 10.03 years) were assigned to four groups (n = 29) and treated with mandibular implant-retained overdentures, implant-supported FPDs (two implants/three unit FPDs), conventional complete dentures, or RPDs. The groups were well matched in terms of gender, age, and the edentulous period. All patients had edentulous maxillary arches and completely or partially edentulous mandibles. All prostheses were mandibular prostheses. The OHIP-14, OHQoL-UK, and SF-36 surveys were used to determine QoL before implant surgery and 1 year after prosthetic treatment. The baseline and 1-year data from 116 patients were analyzed. A significant improvement was found among the QoL scales for all groups (p < 0.05). The most significant improvement was found in the implant-retained overdenture group (15.67 ± 2.47), while the least improvement was found among the implant-supported FPD group (5.14 ± 2.08). The SF-36 test revealed no differences between the before and after treatment scores for general health, pain, vitality, social function, and physical function difficulties (p > 0.05). The only significant difference was found for mental health (p = 0.011). A positive influence on oral health-related QoL was observed in all groups. The QoL values were the most improved in the implant-retained overdenture group. © 2014 by the American College of Prosthodontists.

Detection of orthopaedic foot and ankle implants by security screening devices.

PubMed

Bluman, Eric M; Tankson, Cedric; Myerson, Mark S; Jeng, Clifford L

2006-12-01

A common question asked by patients contemplating foot and ankle surgery is whether the implants used will set off security screening devices in airports and elsewhere. Detectability of specific implants may require the orthopaedic surgeon to provide attestation regarding their presence in patients undergoing implantation of these devices. Only two studies have been published since security measures became more stringent in the post-9/11 era. None of these studies specifically focused on the large numbers of orthopaedic foot and ankle implants in use today. This study establishes empiric data on the detectability by security screening devices of some currently used foot and ankle implants. A list of foot and ankle procedures was compiled, including procedures frequently used by general orthopaedists as well as those usually performed only by foot and ankle specialists. Implants tested included those used for open reduction and internal fixation, joint fusion, joint arthroplasty, osteotomies, arthroreisis, and internal bone stimulation. A test subject walked through a gate-type security device and was subsequently screened using a wand-type detection device while wearing each construct grouping. The screening was repeated with the implants placed within uncooked steak to simulate subcutaneous and submuscular implantation. None of the implants were detected by the gate-type security device. Specific implants that triggered the wand-type detection device regardless of coverage with the meat were total ankle prostheses, implantable bone stimulators, large metatarsophalangeal hemiarthroplasty, large arthroreisis plugs, medial distal tibial locking construct, supramalleolar osteotomy fixation, stainless steel bimalleolar ankle fracture fixation, calcaneal fracture plate and screw constructs, large fragment blade plate constructs, intramedullary tibiotalocalcaneal fusion constructs, and screw fixation for calcaneal osteotomies, ankle arthrodeses, triple arthrodeses, and stainless steel first metatarsophalangeal joint arthrodeses. The placement of implants in meat prevented the detectability of only the stainless steel Jones fracture implant (stainless steel 6.5-mm cannulated screw) and the stainless steel midfoot fusion construct (four stainless steel 4.0-mm cannulated screws). These data may help the orthopaedic surgeon in counseling patients as to the detectability of some orthopaedic foot and ankle implants in use today. Specific constructs for which documentation may need to be provided to the patient are identified. As security standards evolve and the environments in which they are practiced change, empiric testing of many of these devices may need to be repeated.

Wear of ultra-high molecular weight polyethylene against damaged and undamaged stainless steel and diamond-like carbon-coated counterfaces.

PubMed

Firkins, P; Hailey, J L; Fisher, J; Lettington, A H; Butter, R

1998-10-01

The wear of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated polyethylene wear, and the use of ceramic femoral heads in the hip is gaining increasing favour. In the knee prostheses and for smaller diameter femoral heads, the application of hard surface coatings, such as diamond-like carbon, is receiving considerable attention. However, to date, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond-like carbon (DLC) has been compared to stainless steel in its undamaged form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainless steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC than against stainless steel (P < 0.05). The study shows DLC has considerable potential as a femoral bearing surface in artificial joints.

Use and Usefulness of Lower Limb Prostheses.

ERIC Educational Resources Information Center

Buijk, Catharina A.

1988-01-01

Adults (n=181) in the Netherlands were surveyed concerning their use of lower limb prostheses. Results are analyzed in terms of age and sex of users, reason for amputation, level of amputation, description of prosthesis, amount of time able to walk or stand, satisfaction with the prosthesis, and user recommendations. (JDD)

Agile Development of Advanced Prototypes

DTIC Science & Technology

2014-11-01

prostheses: retinal implants, cochlear implants, and neuroprosthetics (EEG controlled artificial limbs); an interactive, virtual experience...demonstrations allowing users to experience, from a patient’s perspective life with three different prostheses: retinal implants, cochlear implants...three experiences were researched and developed. The applications are interactive demonstrations of retinal implants, cochlear implants, and

Updates in inflatable penile prostheses.

PubMed

Henry, Gerard D; Wilson, Steven K

2007-11-01

Throughout history, many attempts to correct erectile dysfunction (ED) have been recorded. For the last 35 years, intracavernosal inflatable prostheses have been used, and these devices have undergone almost constant enhancement. The three-piece inflatable penile prosthesis has the highest patient satisfaction rates and lowest mechanical revision rates of almost any medically implanted device.

Comparison of new bone formation, implant integration, and biocompatibility between RGD-hydroxyapatite and pure hydroxyapatite coating for cementless joint prostheses--an experimental study in rabbits.

PubMed

Bitschnau, Achim; Alt, Volker; Böhner, Felicitas; Heerich, Katharina Elisabeth; Margesin, Erika; Hartmann, Sonja; Sewing, Andreas; Meyer, Christof; Wenisch, Sabine; Schnettler, Reinhard

2009-01-01

This is the first work to report on additional Arginin-Glycin-Aspartat (RGD) coating on precoated hydroxyapatite (HA) surfaces regarding new bone formation, implant bone contact, and biocompatibility compared to pure HA coating and uncoated stainless K-wires. There were 39 rabbits in total with 6 animals for the RGD-HA and HA group for the 4 week time period and 9 animals for each of the 3 implant groups for the 12 week observation. A 2.0 K-wire either with RGD-HA or with pure HA coating or uncoated was placed into the intramedullary canal of the tibia. After 4 and 12 weeks, the tibiae were harvested and three different areas of the tibia were assessed for quantitative and qualitative histology for new bone formation, direct implant bone contact, and formation of multinucleated giant cells. Both RGD-HA and pure HA coating showed statistically higher new bone formation and implant bone contact after 12 weeks than the uncoated K-wire. There were no significant differences between the RGD-HA and the pure HA coating in new bone formation and direct implant bone contact after 4 and 12 weeks. The number of multinucleated giant did not differ significantly between the RGD-HA and HA group after both time points. Overall, no significant effects of an additional RGD coating on HA surfaces were detected in this model after 12 weeks. (c) 2008 Wiley Periodicals, Inc.

Efficacy of Sealing Agents on Preload Maintenance of Screw-Retained Implant-Supported Prostheses.

PubMed

Seloto, Camila Berbel; Strazzi Sahyon, Henrico Badaoui; Dos Santos, Paulo Henrique; Delben, Juliana Aparecida; Assunção, Wirley Gonçalves

The aim of this study was to evaluate the effect of sealing agents on preload maintenance of screw joints. A total of four groups (n = 10 in each group) of abutment/implant systems, including external hexagon implants and antirotational UCLA abutments with a metallic collar in cobalt-chromium alloy, were assessed. In the control group (CG), no sealing agent was used at the abutment screw/implant interface. In the other groups, three different sealing agents were used at the abutment screw/implant interface: anaerobic sealing agent for medium torque (ASMT), anaerobic sealing agent for high torque (ASHT), and cyanoacrylate-based bonding agent (CYAB). All abutments were attached to the implants at 32 ± 1 N.cm. After 48 ± 2 hours of initial tightening, loosing torque (detorque) was measured using a digital torque wrench. Data were analyzed using Shapiro-Wilk, Wilcoxon, and Kruskal-Wallis tests, at 5% level of significance. In the CG and ASMT groups, detorque was lower than the insertion torque (24.6 ± 1.5 N.cm and 24.3 ± 1.1 N.cm, respectively). In the ASHT and CYAB groups, mean detorque increased in comparison to the insertion torque (51.0 ± 7.4 N.cm and 47.7 ± 15.1 N.cm, respectively). The ASHT was more efficient than the other sealing agents, increasing the remaining preload (detorque value) 58.88%. Although the cyanoacrylate-based bonding agent also generated high detorque values, the high standard deviation suggested its lower reliability.

21 CFR 872.3940 - Total temporomandibular joint prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Total temporomandibular joint prosthesis. 872.3940 Section 872.3940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3940 Total temporomandibular joint...

Integrating 3D facial scanning in a digital workflow to CAD/CAM design and fabricate complete dentures for immediate total mouth rehabilitation

PubMed Central

Greven, Marcus; Wismeijer, Daniel

2017-01-01

PURPOSE To integrate extra-oral facial scanning information with CAD/CAM complete dentures to immediately rehabilitate terminal dentition. MATERIALS AND METHODS Ten patients with terminal dentition scheduled for total extraction and immediate denture placement were recruited for this study. The patients were submitted to a facial scanning procedure using the in-office PritiMirror scanner with bite registration records in-situ. Definitive stone cast models and bite records were subsequently submitted to a lab scanning procedure using the lab scanner (iSeries DWOS; Dental Wings). The scanned models were used to create a virtual teeth setup of a complete denture. Using the intra-oral bite records as a reference, the virtual setup was incorporated in the facial scan thereby facilitating a virtual clinical evaluation (teeth try-in) phase. After applying necessary adjustments, the virtual setup was submitted to a CAM procedure where a 5-axis industrial milling machine (M7 CNC; Darton AG General) was used to fabricate a full-milled PMMA immediate provisional prosthesis. RESULTS Total extractions were performed, the dentures were immediately inserted, and subjective clinical fit was evaluated. The immediate provisional prostheses were inserted and clinical fit, occlusion/articulation, and esthetics were subjectively assessed; the results were deemed satisfactory. All provisional prostheses remained three months in function with no notable technical complications. CONCLUSION Ten patients with terminal dentition were treated using a complete digital approach to fabricate complete dentures using CAD/CAM technology. The proposed technique has the potential to accelerate the rehabilitation procedure starting from immediate denture to final implant-supported prosthesis leading to more predictable functional and aesthetics outcomes. PMID:29142646

Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip: a retrospective cohort study in Scotland.

PubMed

Brewster, D H; Stockton, D L; Reekie, A; Ashcroft, G P; Howie, C R; Porter, D E; Black, R J

2013-05-14

Release and dispersion of particles arising from corrosion and wear of total hip arthroplasty (THA) components has raised concerns about a possible increased risk of cancer. Concerns have been heightened by a recent revival in the use of metal-on-metal (MoM) hip prostheses. From a linked database of hospital discharge, cancer registration, and mortality records, we selected a cohort of patients who underwent primary THA (1990-2009) or primary resurfacing arthroplasty (mainly 2000-2009) in Scotland, with follow-up to the end of 2010. Available operation codes did not enable us to distinguish MoM THAs. Indirectly standardised incidence ratios (SIRs) were calculated for selected cancers with standardisation for age, sex, deprivation, and calendar period. The study cohort included 71 990 patients yielding 547 001 person-years at risk (PYAR) and 13 946 cancers diagnosed during follow-up. For the total period of observation combined, the risks of all cancers (SIR: 1.05; 95% CI: confidence interval 1.04-1.07), prostate cancer (SIR: 1.07; 95% CI: 1.01-1.14), and multiple myeloma (SIR: 1.22; 95% CI: 1.06-1.41) were increased. These modest increases in risk emerged in the context of effectively multiple tests of statistical significance, and may reflect inadequate adjustment for confounding factors. For 1317 patients undergoing primary resurfacing arthroplasty between 2000 and 2009 (PYAR=5698), the SIR for all cancers (n=39) was 1.23 (95% CI: 0.87-1.68). In the context of previous research, these results do not suggest a major cause for concern. However, the duration of follow-up of patients receiving recently introduced, new-generation MoM prostheses is too short to rule out a genuinely increased risk of cancer entirely.

[Conservative and operative treatment of working age patients with gonarthritis. Economic considerations].

PubMed

Malzahn, J

2014-06-01

The development of the overall achievements for hospital performance since the introduction in Germany of the diagnosis-related groups (DRG) system in 2003 is the subject of healthcare political discussion. The field of prosthetics is often at the center of considerations. After consideration of the development of achievements with international and regional earnings, the question was investigated how the average expenditure for patients with gonarthritis developed in a time period of 1 year before and after implantation of total knee prostheses. The study was based on individual patient data from the accounting data of the AOK (General Regional Healthcare Insurance) from the categories, inpatient care, panel physician treatment, pharmaceuticals and medicines as well as disability leave periods. The data include the average expenditure and disability times calculated by the AOK for individual patients 12 months before and 12 months after implantation of a total knee prosthesis. The methods were selected because the international classification of diseases (ICD) coding does not allow a differentiation in the degree of severity and, therefore, a comparison of patients who were only conservatively treated within the scope of panel physicians which would have led to problems in risk adjustment. Due to a lack of coding guidelines for treatment by panel physicians, the accuracy of the diagnosis is also limited in comparison to inpatient treatment data. The expenditure and the average disability leave for gonarthritis patients were higher in the year following implantation of total knee prostheses than in the year prior to implantation. No conclusions can be drawn from the provision of service data with respect to the quality of life of the patients. Investigations over a longer time period seem to be necessary.

Single-Surgeon Experience and Complications of a Fixed-Bearing Total Ankle Arthroplasty.

PubMed

Pangrazzi, Garett J; Baker, Erin A; Shaheen, Phillip J; Okeagu, Chikezie N; Fortin, Paul T

2018-01-01

Total ankle arthroplasty (TAA) has historically resulted in inferior survivorship rates compared with total hip and knee arthroplasty, because of technical issues unique to ankle anatomy. In this study, a single-surgeon series of intra- and postoperative complications as well as resultant reoperations/revisions of the Tornier Salto Talaris, a fixed-bearing TAA prosthesis, were reviewed. Medical records from index procedure to latest follow-up of primary TAA were reviewed. Complications were categorized according to the Glazebrook classification; additional complications were documented. Concurrent procedures were recorded, and radiographs were analyzed for alignment, subsidence, and cyst formation. Time to complication onset and learning curve analyses were performed. One hundred four Salto Talaris TAA prostheses (96 patients), with an average follow-up of 46 months, were included. Thirty-five complications were identified in 32 ankles with a 34% complication rate, resulting in 11 reoperations (5 TAA revisions). Technical error (n = 12), wound healing (n = 9), and aseptic loosening (n = 4) were the most common complications, and there were no statistically significant differences in demographics or follow-up duration between cases with versus without complications. In both the cohorts with and without complications, there were moderate, negative correlations between radiographically observed keel osteopenia and lucency (ρ = -0.548, P = .00125, and ρ = -0.416, P = .000303, respectively); also, in the complication cohort, a weak, positive correlation between subsidence and lucency (ρ = 0.357, P = .0450) was found. Salto Talaris TAA survivorship and reoperation rates in our series were comparable with previous reports, using either the same or similar mobile-bearing prostheses; new information regarding complication, radiographic, and learning curve analyses was presented. Level IV, retrospective case series.

Comparison of Customized Cutting Block and Conventional Cutting Instrument in Total Knee Arthroplasty: A Randomized Controlled Trial.

PubMed

Tammachote, Nattapol; Panichkul, Phonthakorn; Kanitnate, Supakit

2018-03-01

Customized cutting block (CCB) was designed to ensure the accurate alignment of knee prostheses during total knee arthroplasty. Given the paucity of CCB efficacy data, we compare CCB with conventional cutting guide using a randomized controlled trial. One hundred eight osteoarthritic knee patients underwent total knee arthroplasty by one experienced surgeon were randomized to receive CCB (n = 54) or conventional cutting instrument (CCI) surgery (n = 54). The primary outcomes were limb alignment, prostheses position, and operative time. The secondary outcomes were hemodynamic alteration after surgery, functional outcomes (modified Western Ontario and McMaster University Osteoarthritis Index) and range of motion at 2 years after surgery. Mean hip-knee-ankle angle in the CCB group was 179.4° ± 1.8° vs 179.1° ± 2.4° in the CCI group, Δ = 0 (95% confidence interval [CI] -0.6 to 1.1, P = .55). Mean operative time was faster in the CCB arm: 93 ± 12 vs 104 ± 12 minutes, Δ = 11 (95% CI -16.7 to -7.2, P < .0001). There were no differences in hemodynamic parameters, mean blood loss (446 [CCB] vs 514 mL [CCI], Δ = -68 [95% CI -138 to 31 mL, P = .21]), postoperative hemoglobin changes, incidence of hypotension (systolic <90 mm Hg), oliguria, and rates of blood transfusion. Functional outcomes and range of motion were also similar. There was no improvement in alignment, hemodynamic changes, blood loss, and knee functional outcomes. CCB reduced surgical time by 11 minutes in our population. CCB cost-effectiveness should be further investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

Validation of a measuring technique with computed tomography for cement penetration into trabecular bone underneath the tibial tray in total knee arthroplasty on a cadaver model

PubMed Central

2014-01-01

Background In total knee arthroplasty (TKA), cement penetration between 3 and 5 mm beneath the tibial tray is required to prevent loosening of the tibia component. The objective of this study was to develop and validate a reliable in vivo measuring technique using CT imaging to assess cement distribution and penetration depth in the total area underneath a tibia prosthesis. Methods We defined the radiodensity ranges for trabecular tibia bone, polymethylmethacrylate (PMMA) cement and cement-penetrated trabecular bone and measured the percentages of cement penetration at various depths after cementing two tibia prostheses onto redundant femoral heads. One prosthesis was subsequently removed to examine the influence of the metal tibia prostheses on the quality of the CT images. The percentages of cement penetration in the CT slices were compared with percentages measured with photographs of the corresponding transversal slices. Results Trabecular bone and cement-penetrated trabecular bone had no overlap in quantitative scale of radio-density. There was no significant difference in mean HU values when measuring with or without the tibia prosthesis. The percentages of measured cement-penetrated trabecular bone in the CT slices of the specimen were within the range of percentages that could be expected based on the measurements with the photographs (p = 0.04). Conclusions CT scan images provide valid results in measuring the penetration and distribution of cement into trabecular bone underneath the tibia component of a TKA. Since the proposed method does not turn metal elements into artefacts, it enables clinicians to assess the width and density of the cement mantle in vivo and to compare the results of different cementing methods in TKA. PMID:25158996

Management of the patient with a total joint replacement: the primary care practitioner's role.

PubMed

Palmer, L M

1999-01-01

The primary care practitioner assumes chief responsibility for patients with arthritis. More than 40 million Americans experience some form of arthritis. Management of the patient with arthritis may include a referral to an orthopedic surgeon for surgical intervention. As estimated, up to 500,000 total joint replacement procedures are performed by orthopedic surgeons each year in the United States. Presurgical evaluation for a total joint replacement is imperative to ensure that the patient can safely undergo this surgical procedure. Postsurgical care of a patient with total joint replacement involves coordinating care with the physical therapist and orthopedic surgeon to ensure adequate follow-through with the recommended rehabilitation program, prophylactic antibiotic coverage, and observation for any complications including infection, deep-vein thrombosis, or loosening of the total-joint prosthesis.

Introduction of a new mobile-bearing total knee prosthesis: minimum three year follow-up of an RCT comparing it with a fixed-bearing device.

PubMed

Beard, D J; Pandit, H; Price, A J; Butler-Manuel, P A; Dodd, C A F; Murray, D W; Goodfellow, J W

2007-12-01

As part of the step-wise validation of a new prosthesis (TMK), we previously published the 1 year results of a randomised controlled trial in patients undergoing bilateral knee replacement [Price A., Rees J., Beard D., Juszczak E. et al. A mobile-bearing total knee prosthesis compared with a fixed-bearing prosthesis. JBJS B 2003;85-B-1:62-7.]. Forty patients had the new mobile-bearing prosthesis implanted in one knee and an established fixed-bearing device in the other (AGC). We now report the 3 year status of these patients and, in addition, review a separate multi-centre cohort of 172 patients who had undergone unilateral arthroplasty with the TMK. No significant differences were found in outcome (American Knee Society Score and Oxford Knee Score) between the two prostheses. The greater incidence of "clicking" in the mobile-bearing knee, reported in the previous review, persisted (TMK=48%, AGC=30%). The presence of this mechanical noise was found to have no relationship with outcome in either of the prostheses. The unilateral cohort study showed an acceptable complication rate for the new prosthesis, although some patients reported subjective instability. The method of controlled introduction of the TMK, of which this constitutes a further step, has allowed us to assess the significance of a reported problem (clicking) and to provide scientific data from which other surgeons can decide about use of the implant.

Acoustic emission studies of posterior stabilized and cruciate retaining knee arthroplasties.

PubMed

Schwarzkopf, Ran; Kummer, Frederick J; Jaffe, William L

2011-09-01

Different acoustic frequencies have been used to diagnose progression of osteoarthritis, gross pathology, and wear in knee prostheses. It is possible that detailed analysis of higher frequencies could detect and quantify the smaller geometric changes (asperities) that develop in articular prosthetic wear. In this study we evaluated the feasibility of using ultrasonic emission to determine total knee arthroplasty (TKA) type and time from implantation using a simple, handheld measurement system. We examined the ultrasound emission generated by similar designs of posterior stabilized (PS) and cruciate retaining (CR) total knee prostheses and native knees of 58 patients and 10 controls. The subjects were asked to sit, rise, sit again, and take five steps while recording the acoustic data from both knees. Acoustic emission analysis examined frequency distributions and power spectrums of the recorded signals, and their relations to prosthesis type and time from implantation. We screened 44 CR and 48 PS TKAs, as well as 24 native knees. Analysis of this data suggested a possibility of differentiating between type of implants, and a relation to time since implantation. Our data suggest that we might be able to assess the status and time from implantation of a TKA by acoustic emission signals. Further in vitro analysis of the relationship of wear to ultrasonic emission data are needed for accurate quantification of arthroplasty wear. A simple, in-office screening tool for TKA patients could indicate which patients require closer follow-up and monitoring due to risk of potential problems.

Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.

PubMed

Martins, Carlos Henrique Gomes; Pires, Regina Helena; Cunha, Aline Oliveira; Pereira, Cristiane Aparecida Martins; Singulani, Junya de Lacorte; Abrão, Fariza; Moraes, Thais de; Mendes-Giannini, Maria José Soares

2016-04-01

Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p < 0.001) than non-albicans Candida strains, after 6 h 37 °C. The total C. albicans CFU from a dual-species biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Manufacturing implant supported auricular prostheses by rapid prototyping techniques.

PubMed

Karatas, Meltem Ozdemir; Cifter, Ebru Demet; Ozenen, Didem Ozdemir; Balik, Ali; Tuncer, Erman Bulent

2011-08-01

Maxillofacial prostheses are usually fabricated on the models obtained following the impression procedures. Disadvantages of conventional impression techniques used in production of facial prosthesis are deformation of soft tissues caused by impression material and disturbance of the patient due to. Additionally production of prosthesis by conventional methods takes longer time. Recently, rapid prototyping techniques have been developed for extraoral prosthesis in order to reduce these disadvantages of conventional methods. Rapid prototyping technique has the potential to simplify the procedure and decrease the laboratory work required. It eliminates the need for measurement impression procedures and preparation of wax model to be performed by prosthodontists themselves In the near future this technology will become a standard for fabricating maxillofacial prostheses.

External breast prostheses. A survey of their use by women after mastectomy.

PubMed

Tanner, R; Abraham, S F; Llewellyn-Jones, D

1983-03-19

Women who have had a mastectomy for breast cancer have to cope with two major problems: first, that they have cancer, and second, that they have lost their physical appearance. The provision of an appropriate prosthesis can reduce the sense of disfigurement. If women were to obtain the full psychological benefit of wearing a breast prosthesis, they need to be informed about the available breast forms, have an opportunity to choose between them, and to be satisfied with their choice. In this study of 49 women, only 44% had had the opportunity to choose a prosthesis, 28% were dissatisfied with their prostheses, and 17% were still using temporary prostheses.

Macro-structural effect of metal surfaces treated using computer-assisted yttrium-aluminum-garnet laser scanning on bone-implant fixation.

PubMed

Hirao, Makoto; Sugamoto, Kazuomi; Tamai, Noriyuki; Oka, Kunihiro; Yoshikawa, Hideki; Mori, Yusuke; Sasaki, Takatomo

2005-05-01

Porous coatings have been applied to the surface of prosthetic devices to foster stable device fixation. The coating serves as a source of mechanical interlocking and may stimulate healthy bone growth through osseointegrated load transfer in cementless arthroplasty. Joint arthroplasty by porous-coated prostheses is one of the most common surgical treatments, and has provided painless and successful joint mobility. However, long-term success is often impaired by the loss of fixation between the prosthesis and bone. Porous-coated prostheses are associated with several disadvantages, including metal debris from porous coatings (third body wear particles) and irregular micro-texture of metal surfaces. Consequently, quantitative histological analysis has been very difficult. These issues arise because the porous coating treatment is based on addition of material and is not precisely controllable. We recently developed a precisely controllable porous texture technique based on material removal by yttrium-aluminum-garnet laser. Free shapes can be applied to complex, three-dimensional hard metal surfaces using this technique. In this study, tartan check shapes made by crossing grooves and dot shapes made by forming holes were produced on titanium (Ti6A14V) or cobalt chrome (CoCr) and evaluated with computer-assisted histological analysis and measurement of bone-metal interface shear strength. Width of grooves or holes ranged from 100 to 800 mum (100, 200, 500, and 800 microm), with a depth of 500 microm. When the cylindrical porous-texture-treated metal samples (diameter, 5 mm; height, 15 mm) were implanted into a rabbit femoral condyle, bone tissue with bone trabeculae formed in the grooves and holes after 2 or 4 weeks, especially in 500-microm-wide grooves. Abundant osteoconduction was consistently observed throughout 500-microm-wide grooves in both Ti6A14V and CoCr. Speed of osteoconduction was faster in Ti6A14V than in CoCr, especially in the tartan check shape made of 500-microm-wide grooves. In pushout testing, the tartan check shape made of 500-microm-wide grooves had significantly higher bone-metal interface shear strength than the dot shape or commercial porous coating. These results indicate that the tartan check shape made of 500-microm-wide grooves on metal surfaces has potential for clinical application in artificial prosthesis design.

Medicare Reimbursement for Total Joint Arthroplasty: The Driving Forces.

PubMed

Padegimas, Eric M; Verma, Kushagra; Zmistowski, Benjamin; Rothman, Richard H; Purtill, James J; Howley, Michael

2016-06-15

Total joint arthroplasty is a large and growing part of the U.S. Medicare budget, drawing attention to how much providers are paid for their services. The purpose of this study was to examine the variables that affect total joint arthroplasty reimbursement. Along with standard economic variables, we include unique health-care variables. Given the focus on value in the Affordable Care Act, the model examines the relationship of the quality of care to total joint arthroplasty reimbursement. We hoped to find that reimbursement patterns reward quality and reflect standard economic principles. Multivariable regression was performed to identify variables that correlate with Medicare reimbursement for total joint arthroplasty. Inpatient charge or reimbursement data on Medicare reimbursements were available for 2,750 hospitals with at least 10 discharges for uncomplicated total joint arthroplasty from the Centers for Medicare & Medicaid Services (CMS) for fiscal year 2011. Reimbursement variability was examined by using the Dartmouth Atlas to group institutions into hospital referral regions and hospital service areas. Independent variables were taken from the Dartmouth Atlas, CMS, the WWAMI (Washington, Wyoming, Alaska, Montana, Idaho) Rural Health Research Center, and the United States Census. There were 427,207 total joint arthroplasties identified, with a weighted mean reimbursement of $14,324.84 (range, $9,103 to $38,686). Nationally, the coefficient of variation for reimbursements was 0.19. The regression model accounted for 52.5% of reimbursement variation among providers. The total joint arthroplasty provider volume (p < 0.001) and patient satisfaction (p < 0.001) were negatively correlated with reimbursement. Government ownership of a hospital (p < 0.001) and higher Medicare costs (p < 0.001) correlated positively with reimbursement. Medicare reimbursements for total joint arthroplasty are highly variable. Greater reimbursement was associated with lower patient volume, lower patient satisfaction, a healthier patient population, and government ownership of a hospital. As value-based reimbursement provisions of the Affordable Care Act are implemented, there will be dramatic changes in total joint arthroplasty reimbursements. To meet these changes, providers should expect qualities such as high patient volume, willingness to care for sicker patient populations, patient satisfaction, safe outcomes, and procedural demand to correlate with their reimbursement. Practicing orthopaedic surgeons and hospital administrators should be aware of discrepancies in inpatient reimbursement for total joint arthroplasty from Medicare. Furthermore, these discrepancies are not associated with typical economic factors. These findings warrant further investigation and collaboration between policymakers and providers to develop value-based reimbursement. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Effect of progressive wear on the contact mechanics of hip replacements--does the realistic surface profile matter?

PubMed

Wang, Ling; Yang, Wenjian; Peng, Xifeng; Li, Dichen; Dong, Shuangpeng; Zhang, Shu; Zhu, Jinyu; Jin, Zhongmin

2015-04-13

The contact mechanics of artificial metal-on-polyethylene hip joints are believed to affect the lubrication, wear and friction of the articulating surfaces and may lead to the joint loosening. Finite element analysis has been widely used for contact mechanics studies and good agreements have been achieved with current experimental data; however, most studies were carried out with idealist spherical geometries of the hip prostheses rather than the realistic worn surfaces, either for simplification reason or lacking of worn surface profile. In this study, the worn surfaces of the samples from various stages of hip simulator testing (0 to 5 million cycles) were reconstructed as solid models and were applied in the contact mechanics study. The simulator testing results suggested that the center of the head has various departure value from that of the cup and the value of the departure varies with progressively increased wear. This finding was adopted into the finite element study for better evaluation accuracy. Results indicated that the realistic model provided different evaluation from that of the ideal spherical model. Moreover, with the progressively increased wear, large increase of the contact pressure (from 12 to 31 MPa) was predicted on the articulating surface, and the predicted maximum von Mises stress was increased from 7.47 to 13.26 MPa, indicating the marked effect of the worn surface profiles on the contact mechanics of the joint. This study seeks to emphasize the importance of realistic worn surface profile of the acetabular cup especially following large wear volume. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficacy of a novel PCR- and microarray-based method in diagnosis of a prosthetic joint infection

PubMed Central

2014-01-01

Background and purpose Polymerase chain reaction (PCR) methods enable detection and species identification of many pathogens. We assessed the efficacy of a new PCR and microarray-based platform for detection of bacteria in prosthetic joint infections (PJIs). Methods This prospective study involved 61 suspected PJIs in hip and knee prostheses and 20 negative controls. 142 samples were analyzed by Prove-it Bone and Joint assay. The laboratory staff conducting the Prove-it analysis were not aware of the results of microbiological culture and clinical findings. The results of the analysis were compared with diagnosis of PJIs defined according to the Musculoskeletal Infection Society (MSIS) criteria and with the results of microbiological culture. Results 38 of 61 suspected PJIs met the definition of PJI according to the MSIS criteria. Of the 38 patients, the PCR detected bacteria in 31 whereas bacterial culture was positive in 28 patients. 15 of the PJI patients were undergoing antimicrobial treatment as the samples for analysis were obtained. When antimicrobial treatment had lasted 4 days or more, PCR detected bacteria in 6 of the 9 patients, but positive cultures were noted in only 2 of the 9 patients. All PCR results for the controls were negative. Of the 61 suspected PJIs, there were false-positive PCR results in 6 cases. Interpretation The Prove-it assay was helpful in PJI diagnostics during ongoing antimicrobial treatment. Without preceding treatment with antimicrobials, PCR and microarray-based assay did not appear to give any additional information over culture. PMID:24564748

Using Noncontingent Reinforcement to Increase Compliance with Wearing Prescription Prostheses

ERIC Educational Resources Information Center

Richling, Sarah M.; Rapp, John T.; Carroll, Regina A.; Smith, Jeanette N.; Nystedt, Aaron; Siewert, Brook

2011-01-01

We evaluated the effects of noncontingent reinforcement (NCR) on compliance with wearing foot orthotics and a hearing aid with 2 individuals. Results showed that NCR increased the participants' compliance with wearing prescription prostheses to 100% after just a few 5-min sessions, and the behavior change was maintained during lengthier sessions.…

[Image processing system of visual prostheses based on digital signal processor DM642].

PubMed

Xie, Chengcheng; Lu, Yanyu; Gu, Yun; Wang, Jing; Chai, Xinyu

2011-09-01

This paper employed a DSP platform to create the real-time and portable image processing system, and introduced a series of commonly used algorithms for visual prostheses. The results of performance evaluation revealed that this platform could afford image processing algorithms to be executed in real time.

Composite Materials for Maxillofacial Prostheses.

DTIC Science & Technology

1983-02-01

the most promise for producing elastomeric-shelled microcapsules containing an inert liquid. While much of the diverse field of microencapsulation is...Processes and Applications, Chicago, 28 August 1973. 11. Gutchko, M. H., Microcapsules and Microencapsulation Techniques. Noyes Data Corporation, Park Ridge...necesaryv and identify by block number) * MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : * SOFT FILLERS; ELASTOMER COMPOSITES 2L

Computational comparison of aortic root stresses in presence of stentless and stented aortic valve bio-prostheses.

PubMed

Nestola, M G C; Faggiano, E; Vergara, C; Lancellotti, R M; Ippolito, S; Antona, C; Filippi, S; Quarteroni, A; Scrofani, R

2017-02-01

We provide a computational comparison of the performance of stentless and stented aortic prostheses, in terms of aortic root displacements and internal stresses. To this aim, we consider three real patients; for each of them, we draw the two prostheses configurations, which are characterized by different mechanical properties and we also consider the native configuration. For each of these scenarios, we solve the fluid-structure interaction problem arising between blood and aortic root, through Finite Elements. In particular, the Arbitrary Lagrangian-Eulerian formulation is used for the numerical solution of the fluid-dynamic equations and a hyperelastic material model is adopted to predict the mechanical response of the aortic wall and the two prostheses. The computational results are analyzed in terms of aortic flow, internal wall stresses and aortic wall/prosthesis displacements; a quantitative comparison of the mechanical behavior of the three scenarios is reported. The numerical results highlight a good agreement between stentless and native displacements and internal wall stresses, whereas higher/non-physiological stresses are found for the stented case.

A system verification platform for high-density epiretinal prostheses.

PubMed

Chen, Kuanfu; Lo, Yi-Kai; Yang, Zhi; Weiland, James D; Humayun, Mark S; Liu, Wentai

2013-06-01

Retinal prostheses have restored light perception to people worldwide who have poor or no vision as a consequence of retinal degeneration. To advance the quality of visual stimulation for retinal implant recipients, a higher number of stimulation channels is expected in the next generation retinal prostheses, which poses a great challenge to system design and verification. This paper presents a system verification platform dedicated to the development of retinal prostheses. The system includes primary processing, dual-band power and data telemetry, a high-density stimulator array, and two methods for output verification. End-to-end system validation and individual functional block characterization can be achieved with this platform through visual inspection and software analysis. Custom-built software running on the computers also provides a good way for testing new features before they are realized by the ICs. Real-time visual feedbacks through the video displays make it easy to monitor and debug the system. The characterization of the wireless telemetry and the demonstration of the visual display are reported in this paper using a 256-channel retinal prosthetic IC as an example.

Clinical Management of Implant Prostheses in Patients with Bruxism

PubMed Central

Komiyama, Osamu; Lobbezoo, Frank; De Laat, Antoon; Iida, Takashi; Kitagawa, Tsuyoshi; Murakami, Hiroshi; Kato, Takao; Kawara, Misao

2012-01-01

There is general agreement that excessive stress to the bone-implant interface may result in implant overload and failure. Early failure of the implant due to excessive loading occurs shortly after uncovering the implant. Excess load on a final restoration after successful implant integration can result in physical failure of the implant structure. Many clinicians believe that overload of dental implants is a risk factor for vertical peri-implant bone loss and/or may be detrimental for the suprastructure in implant prostheses. It has been documented that occlusal parafunction, such as, bruxism (tooth grinding and clenching) affects the outcome of implant prostheses, but there is no evidence for a causal relation between the failures and overload of dental implants. In spite of this lack of evidence, often metal restorations are preferred instead of porcelain for patients in whom bruxism is presumed on the basis of tooth wear. The purpose of this paper is to discuss the importance of the occlusal scheme used in implant restorations for implant longevity and to suggest a clinical approach and occlusal materials for implant prostheses in order to prevent complications related to bruxism. PMID:22701484

A Morlet wavelet signal analysis with a Daubechies filter for the wear assessment of hip prostheses coated with diamond-like carbon by triboadhesion.

PubMed

Rodríguez-Lelis, Jose Maria; Mata, Dagoberto Tolosa; Vargas-Treviño, Marciano; Navarro-Torres, Jose; Piña-Piña, Gilberto; Abundez-Pliego, Arturo

2010-08-01

In the present work, based on high frequency wavelet analysis of dynamic signals of mechanical systems, a multiple-resolution wavelet analysis is carried out, to the signal obtained from an accelerometer mounted on the structure of a hip prosthesis wearing test device. The prostheses employed had a femoral head made of aluminum oxide and the acetabular cup of ultra-high-molecular-weight polyethylene. The first two aluminum oxide femoral heads were coated with diamond-like carbon and a third one was tested without coating and used as a reference. The coating was carried out by triboadhesion. Tests results showed that maximum vibration amplitude reached after 32 hr for the coated prostheses was 0.2 g. The noncoated prosthesis amplitude presented was 0.75 g in the same time interval. These values were attributed to wear damage on the surface of the prostheses, indicating that thin film DLC coating caused an increase of stiffness on the surface and therefore an increase in wear resistance approximately of 314%.

Effects of underestimating the kinematics of trunk rotation on simultaneous reaching movements: predictions of a biomechanical model

PubMed Central

2013-01-01

Background Rotation of the torso while reaching produces torques (e.g., Coriolis torque) that deviate the arm from its planned trajectory. To ensure an accurate reaching movement, the brain may take these perturbing torques into account during movement planning or, alternatively, it may correct hand trajectory during movement execution. Irrespective of the process selected, it is expected that an underestimation of trunk rotation would likely induce inaccurate shoulder and elbow torques, resulting in hand deviation. Nonetheless, it is still undetermined to what extent a small error in the perception of trunk rotations, translating into an inappropriate selection of motor commands, would affect reaching accuracy. Methods To investigate, we adapted a biomechanical model (J Neurophysiol 89: 276-289, 2003) to predict the consequences of underestimating trunk rotations on right hand reaching movements performed during either clockwise or counter clockwise torso rotations. Results The results revealed that regardless of the degree to which the torso rotation was underestimated, the amplitude of hand deviation was much larger for counter clockwise rotations than for clockwise rotations. This was attributed to the fact that the Coriolis and centripetal joint torques were acting in the same direction during counter clockwise rotation yet in opposite directions during clockwise rotations, effectively cancelling each other out. Conclusions These findings suggest that in order to anticipate and compensate for the interaction torques generated during torso rotation while reaching, the brain must have an accurate prediction of torso rotation kinematics. The present study proposes that when designing upper limb prostheses controllers, adding a sensor to monitor trunk kinematics may improve prostheses control and performance. PMID:23758968

Gait Biomechanics of Individuals with Transtibial Amputation: Effect of Suspension System

PubMed Central

Eshraghi, Arezoo; Abu Osman, Noor Azuan; Karimi, Mohammad; Gholizadeh, Hossein; Soodmand, Ehsan; Abas, Wan Abu Bakar Wan

2014-01-01

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. PMID:24865351

Hypersensitivity reactions to metal implants: laboratory options.

PubMed

Carossino, Anna Maria; Carulli, Christian; Ciuffi, Simone; Carossino, Roberto; Zappoli Thyrion, Giorgia Donata; Zonefrati, Roberto; Innocenti, Massimo; Brandi, Maria Luisa

2016-11-23

All implant compounds undergo an electrochemical process when in contact with biological fluids, as well as mechanical corrosion due to abrasive wear, with production of metal debris that may inhibit repair processes. None of the commonly-used methods can diagnose implant allergies when used singly, therefore a panel of tests should be performed on allergic patients as pre-operative screening, or when a postoperative metal sensitisation is suspected. We analysed patients with painful prostheses and subjects prone to allergies using the Patch Test in comparison with the Lymphocyte Transformation Test. Cytokine production was evaluated to identify prognostic markers for early diagnosis of aseptic loosening. Metal debris endocytosis and cytoskeletal rearrangement was visualised by confocal microscopy. Our results demonstrate that the Lymphocyte Transformation Test can identify patients who have a predisposition to develop allergic reactions and can confirm the diagnosis of hypersensitivity in patients with painful prostheses. The prevalence of a Th2-cytokine pattern may be used to identify predisposition to the development of allergic diseases, while the selective presence of osteoclastogenic cytokines may be used as predictor of a negative outcome in patients with painful prosthesis. The hypothesis of the prognostic value of these cytokines as early markers of aseptic loosening is attractive, but its confirmation would require extensive testing. The Lymphocyte Transformation Test is the most suitable method for testing systemic allergies. We suggest that the combined use of the Patch Test and the Lymphocyte Transformation Test, associated with cytokine detection in selected patients, could provide a useful tool for preventive evaluation of immune reactivity in patients undergoing primary joint replacement surgery, and for clinical monitoring of the possible onset of a metal sensitization in patients with implanted devices.

Energy expenditure of wheeling and walking during prosthetic rehabilitation in a woman with bilateral transfemoral amputations.

PubMed

Wu, Y J; Chen, S Y; Lin, M C; Lan, C; Lai, J S; Lien, I N

2001-02-01

To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations. Observational, single patient, descriptive. An 80-meter long rectangular hallway in a rehabilitation unit. A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit. The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation. Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge. People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.

Bone-anchored titanium implants for auricular rehabilitation: case report and review of literature.

PubMed

Gumieiro, Emne Hammoud; Dib, Luciano Lauria; Jahn, Ricardo Schmitutz; Santos Junior, João Ferreira dos; Nannmark, Ulf; Granström, Gösta; Abrahão, Márcio

2009-01-01

Osseointegrated implants have acquired an important role in the prosthetic rehabilitation of patients with craniofacial defects. The main indications are lack of local tissue for autogenous reconstruction, previous reconstruction failure and selection of this technique by the patient. This paper presents a clinical case and discusses indications and advantages of the osseointegrated implant technique for retention of auricular prostheses. Case report, Universidade Federal de São Paulo (UNIFESP). A female patient received three auricular implants after surgical resection of a hemangioma in her left ear. The time taken for osseointegration of the temporal bone was three months. After fabrication of the implant-retained auricular prosthesis, the patient was monitored for 12 months. The clinical parameters evaluated showed good postoperative healing, healthy peri-implant tissue, good hygiene and no loss of implants. Good hygiene combined with thin and immobile peri-implant soft tissues resulted in minimal complications. Craniofacial implant integration appears to be site-dependent; increasing age affects osseointegration in the temporal bone. The frequency of adverse skin reactions in peri-implant tissues is generally low. The surgical technique for rehabilitation using implant-retained auricular prostheses seems to be simple. It is associated with low rates of adverse skin reactions and long-term complications. Prostheses anchored by osseointegrated implants seem to provide better retention than do prostheses supported on spectacle frames, less risk of discoloration through the use of adhesives and better esthetic results than do prostheses anchored in the surgical cavity.

Toward Optimal Target Placement for Neural Prosthetic Devices

PubMed Central

Cunningham, John P.; Yu, Byron M.; Gilja, Vikash; Ryu, Stephen I.; Shenoy, Krishna V.

2008-01-01

Neural prosthetic systems have been designed to estimate continuous reach trajectories (motor prostheses) and to predict discrete reach targets (communication prostheses). In the latter case, reach targets are typically decoded from neural spiking activity during an instructed delay period before the reach begins. Such systems use targets placed in radially symmetric geometries independent of the tuning properties of the neurons available. Here we seek to automate the target placement process and increase decode accuracy in communication prostheses by selecting target locations based on the neural population at hand. Motor prostheses that incorporate intended target information could also benefit from this consideration. We present an optimal target placement algorithm that approximately maximizes decode accuracy with respect to target locations. In simulated neural spiking data fit from two monkeys, the optimal target placement algorithm yielded statistically significant improvements up to 8 and 9% for two and sixteen targets, respectively. For four and eight targets, gains were more modest, as the target layouts found by the algorithm closely resembled the canonical layouts. We trained a monkey in this paradigm and tested the algorithm with experimental neural data to confirm some of the results found in simulation. In all, the algorithm can serve not only to create new target layouts that outperform canonical layouts, but it can also confirm or help select among multiple canonical layouts. The optimal target placement algorithm developed here is the first algorithm of its kind, and it should both improve decode accuracy and help automate target placement for neural prostheses. PMID:18829845

Differences of oral health conditions between adults and older adults: A census in a Southern Brazilian city.

PubMed

Boscato, Noeli; Schuch, Helena S; Grasel, Claudia E; Goettems, Marilia L

2016-09-01

To assess differences in the oral diseases/conditions between adults and older adults. A cross-sectional study was carried out with all adults and older adults in Luzerna, South Brazil (n = 569). Clinical data included use of and need for dental prostheses; number of decayed, missing and filled teeth; and temporomandibular disorder. Differences between adults and older adults were evaluated using χ(2) -tests. Associations between independent variables and the use of and need for dental prostheses were determined using Poisson regression analyses (P < 0.05). Increased number of decayed, missing and filled teeth, use of and need for dental prostheses, higher use of complete dentures, and fewer temporomandibular disorder signs and symptoms were observed in older adults. After adjustments, lower social class (P = 0.001) and unmarried status (P = 0.05) were associated with greater need for prosthetic rehabilitation. Women (P = 0.02), older individuals (P < 0.001) and those of lower socioeconomic status (P = 0.001) had a higher risk of using prostheses. A significant difference of oral conditions between adults and older adults was observed. The frequency of use of and need for dental prostheses was higher for older adults, although they had reported lower frequency of temporomandibular disorder. Women, married and individuals of higher socioeconomic status showed better oral health conditions. Geriatr Gerontol Int 2016; 16: 1014-1020. © 2015 Japan Geriatrics Society.

3D-printed upper limb prostheses: a review.

PubMed

Ten Kate, Jelle; Smit, Gerwin; Breedveld, Paul

2017-04-01

This paper aims to provide an overview with quantitative information of existing 3D-printed upper limb prostheses. We will identify the benefits and drawbacks of 3D-printed devices to enable improvement of current devices based on the demands of prostheses users. A review was performed using Scopus, Web of Science and websites related to 3D-printing. Quantitative information on the mechanical and kinematic specifications and 3D-printing technology used was extracted from the papers and websites. The overview (58 devices) provides the general specifications, the mechanical and kinematic specifications of the devices and information regarding the 3D-printing technology used for hands. The overview shows prostheses for all different upper limb amputation levels with different types of control and a maximum material cost of $500. A large range of various prostheses have been 3D-printed, of which the majority are used by children. Evidence with respect to the user acceptance, functionality and durability of the 3D-printed hands is lacking. Contrary to what is often claimed, 3D-printing is not necessarily cheap, e.g., injection moulding can be cheaper. Conversely, 3D-printing provides a promising possibility for individualization, e.g., personalized socket, colour, shape and size, without the need for adjusting the production machine. Implications for rehabilitation Upper limb deficiency is a condition in which a part of the upper limb is missing as a result of a congenital limb deficiency of as a result of an amputation. A prosthetic hand can restore some of the functions of a missing limb and help the user in performing activities of daily living. Using 3D-printing technology is one of the solutions to manufacture hand prostheses. This overview provides information about the general, mechanical and kinematic specifications of all the devices and it provides the information about the 3D-printing technology used to print the hands.

CNC-milled titanium frameworks supported by implants in the edentulous jaw: a 10-year comparative clinical study.

PubMed

Örtorp, Anders; Jemt, Torsten

2012-03-01

No long-term clinical studies covering more than 5 years are available on Computer Numeric Controlled (CNC) milled titanium frameworks. To evaluate and compare the clinical and radiographic performance of implant-supported prostheses provided with CNC titanium frameworks in the edentulous jaw with prostheses with cast gold-alloy frameworks during the first 10 years of function. Altogether, 126 edentulous patients were by random provided with 67 prostheses with titanium frameworks (test) in 23 maxillas and 44 mandibles, and with 62 prostheses with gold-alloy castings (control) in 31 maxillas and 31 mandibles. Clinical and radiographic 10-year data were collected for the groups and statistically compared on patient level. The 10-year prosthesis and implant cumulative survival rate was 95.6% compared with 98.3%, and 95.0% compared with 97.9% for test and control groups, respectively (p > .05). No implants were lost after 5 years of follow-up. Smokers lost more implants than nonsmokers after 5 years of follow-up (p < .01). Mean marginal bone loss in the test group was 0.7 mm (SD 0.61) and 0.7 mm (SD 0.85) in the maxilla and mandible, with similar pattern in the control group (p > .05), respectively. One prosthesis was lost in each group due to loss of implants, and one prosthesis failed due to framework fracture in the test group. Two metal fractures were registered in each group. More appointments of maintenance were needed for the prostheses in the maxilla compared with those in the mandible (p < .001). The frequency of complications was low with similar clinical and radiological performance for both groups during 10 years. CNC-milled titanium frameworks are a viable alternative to gold-alloy castings for restoring patients with implant-supported prostheses in the edentulous jaw. © 2009 Wiley Periodicals, Inc.

Reduction of metal artifacts from hip prostheses on CT images of the pelvis: value of iterative reconstructions.

PubMed

Morsbach, Fabian; Bickelhaupt, Sebastian; Wanner, Guido A; Krauss, Andreas; Schmidt, Bernhard; Alkadhi, Hatem

2013-07-01

To assess the value of iterative frequency split-normalized (IFS) metal artifact reduction (MAR) for computed tomography (CT) of hip prostheses. This study had institutional review board and local ethics committee approval. First, a hip phantom with steel and titanium prostheses that had inlays of water, fat, and contrast media in the pelvis was used to optimize the IFS algorithm. Second, 41 consecutive patients with hip prostheses who were undergoing CT were included. Data sets were reconstructed with filtered back projection, the IFS algorithm, and a linear interpolation MAR algorithm. Two blinded, independent readers evaluated axial, coronal, and sagittal CT reformations for overall image quality, image quality of pelvic organs, and assessment of pelvic abnormalities. CT attenuation and image noise were measured. Statistical analysis included the Friedman test, Wilcoxon signed-rank test, and Levene test. Ex vivo experiments demonstrated an optimized IFS algorithm by using a threshold of 2200 HU with four iterations for both steel and titanium prostheses. Measurements of CT attenuation of the inlays were significantly (P < .001) more accurate for IFS when compared with filtered back projection. In patients, best overall and pelvic organ image quality was found in all reformations with IFS (P < .001). Pelvic abnormalities in 11 of 41 patients (27%) were diagnosed with significantly (P = .002) higher confidence on the basis of IFS images. CT attenuation of bladder (P < .001) and muscle (P = .043) was significantly less variable with IFS compared with filtered back projection and linear interpolation MAR. In comparison with that of FBP and linear interpolation MAR, noise with IFS was similar close to and far from the prosthesis (P = .295). The IFS algorithm for CT image reconstruction significantly reduces metal artifacts from hip prostheses, improves the reliability of CT number measurements, and improves the confidence for depicting pelvic abnormalities.

Fracture analysis of randomized implant-supported fixed dental prostheses

PubMed Central

Esquivel-Upshaw, Josephine F.; Mehler, Alex; Clark, Arthur E.; Neal, Dan; Anusavice, Kenneth J.

2014-01-01

Objective Fractures of posterior fixed dental all-ceramic prostheses can be caused by one or more factors including prosthesis design, flaw distribution, direction and magnitude of occlusal loading, and nature of supporting infrastructure (tooth root/implant), and presence of adjacent teeth. This clinical study of implant-supported, all-ceramic fixed dental prostheses, determined the effects of (1) presence of a tooth distal to the most distal retainer; (2) prosthesis loading either along the non-load bearing or load bearing areas; (3) presence of excursive contacts or maximum intercuspation contacts in the prosthesis; and (4) magnitude of bite force on the occurrence of veneer ceramic fracture. Methods 89 implant-supported FDPs were randomized as either a three-unit posterior metal-ceramic (Au-Pd-Ag alloy and InLine POM, Ivoclar, Vivadent) FDP or a ceramic-ceramic (ZirCAD and ZirPress, Ivoclar, Vivadent) FDP. Two implants (Osseospeed, Dentsply) and custom abutments (Atlantis, Dentsply) supported these FDPs, which were cemented with resin cement (RelyX Universal Cement). Baseline photographs were made with markings of teeth from maximum intercuspation (MI) and excursive function. Patients were recalled at 6 months and 1 to 3 years. Fractures were observed, their locations recorded, and images compared with baseline photographs of occlusal contacts. Conclusion No significant relationship exists between the occurrence of fracture and: (1) the magnitude of bite force; (2) a tooth distal to the most distal retainer; and (3) contacts in load-bearing or non-load-bearing areas. However, there was a significantly higher likelihood of fracture in areas with MI contacts only. Clinical Significance This clinical study demonstrates that there is a need to evaluate occlusion differently with implant-supported prostheses than with natural tooth supported prostheses because of the absence of a periodontal ligament. Implant supported prostheses should have minimal occlusion and lighter contacts than ones supported by natural dentition. PMID:25016139

Health Information in Bosnian (bosanski)

MedlinePlus

... new window. A Expand Section After Surgery Home Care After Total Joint Replacement - bosanski (Bosnian) Bilingual PDF Health Information ... Information Translations J Expand Section Joint Disorders Home Care After Total Joint Replacement - bosanski (Bosnian) Bilingual PDF Health Information ...

The Reality of Myoelectric Prostheses: Understanding What Makes These Devices Difficult for Some Users to Control

PubMed Central

Chadwell, Alix; Kenney, Laurence; Thies, Sibylle; Galpin, Adam; Head, John

2016-01-01

Users of myoelectric prostheses can often find them difficult to control. This can lead to passive-use of the device or total rejection, which can have detrimental effects on the contralateral limb due to overuse. Current clinically available prostheses are “open loop” systems, and although considerable effort has been focused on developing biofeedback to “close the loop,” there is evidence from laboratory-based studies that other factors, notably improving predictability of response, may be as, if not more, important. Interestingly, despite a large volume of research aimed at improving myoelectric prostheses, it is not currently known which aspect of clinically available systems has the greatest impact on overall functionality and everyday usage. A protocol has, therefore, been designed to assess electromyographic (EMG) skill of the user and predictability of the prosthesis response as significant parts of the control chain, and to relate these to functionality and everyday usage. Here, we present the protocol and results from early pilot work. A set of experiments has been developed. First, to characterize user skill in generating the required level of EMG signal, as well as the speed with which users are able to make the decision to activate the appropriate muscles. Second, to measure unpredictability introduced at the skin–electrode interface, in order to understand the effects of the socket-mounted electrode fit under different loads on the variability of time taken for the prosthetic hand to respond. To evaluate prosthesis user functionality, four different outcome measures are assessed. Using a simple upper limb functional task prosthesis users are assessed for (1) success of task completion, (2) task duration, (3) quality of movement, and (4) gaze behavior. To evaluate everyday usage away from the clinic, the symmetricity of their real-world arm use is assessed using activity monitoring. These methods will later be used to assess a prosthesis user cohort to establish the relative contribution of each control factor to the individual measures of functionality and everyday usage (using multiple regression models). The results will support future researchers, designers, and clinicians in concentrating their efforts on the area that will have the greatest impact on improving prosthesis use. PMID:27597823

The psychosocial impacts of implantation on the dental aesthetics of missing anterior teeth patients.

PubMed

Chen, P; Yu, S; Zhu, G

2012-12-01

The aim of the current study was to investigate the psychosocial impact of dental aesthetics among patients who received anterior implant-supported prostheses. The current study is a cross-sectional evaluation involving 115 individuals who had gone through treatment at the dental clinics of general hospitals. Participants completed the Chinese version of the psychosocial impact of dental aesthetics questionnaire (PIDAQ) before implantation and six months after crown restoration. Basic demographic information was recorded. Six months after implant crown restoration, participants were asked to self-assess their own oral aesthetics compared to before implantation. A total of 106 patients completed the study. PIDAQ scores correlated significantly with the self-assessment of the degree of oral aesthetics. Six months after crown restoration, the two factors (social impact and aesthetic attitude) decreased and the dental self-confidence score increased significantly compared to pre-implantation scores. Gender and education level significantly affected PIDAQ. Anterior implant-supported prostheses significantly affected the patients' psychosocial perception. Implantation of missing anterior teeth can significantly improve patients' negative psychosocial impact of dental aesthetics. Gender and education level are correlated with the degree of improvement. The PIDAQ can be used in assessing the psychosocial effects of implantation in missing anterior teeth.

Image- and model-based surgical planning in otolaryngology.

PubMed

Korves, B; Klimek, L; Klein, H M; Mösges, R

1995-10-01

Preoperative evaluation of any operating field is essential for the preparation of surgical procedures. The relationship between pathology and adjacent structures, and anatomically dangerous sites need to be analyzed for the determination of intraoperative action. For the simulation of surgery using three-dimensional imaging or individually manufactured plastic patient models, the authors have worked out different procedures. A total of 481 surgical interventions in the maxillofacial region, paranasal sinuses, orbit, and the anterior and middle skull base, in addition to neurotologic procedures were presurgically simulated using three-dimensional imaging and image manipulation. An intraoperative simulation device, part of the Aachen Computer-Assisted Surgery System, had been applied in 407 of these cases. In seven patients, stereolithography was used to create plastic patient models for the preparation of reconstructive surgery and prostheses fabrication. The disadvantages of this process include time and cost; however, the advantages included (1) a better understanding of the anatomic relationships, (2) the feasibility of presurgical simulation of the prevailing procedure, (3) an improved intraoperative localization accuracy, (4) prostheses fabrication in reconstructive procedures with an approach to more accuracy, (5) permanent recordings for future requirements or reconstructions, and (6) improved residency education.

Surgical débridement and parenteral antibiotics in infected revision total knee arthroplasty.

PubMed

Chiu, Fang-Yao; Chen, Chuan-Mu

2007-08-01

Whether surgical débridement and parenteral antibiotics with prosthesis retention for infected revision TKA eradicates infection is not well established. We sought to determine the prevalence of reinfection. Between 1992 and 2003, we prospectively followed 40 consecutive patients with deep infection after revision TKA. These patients had no prosthesis loosening or malalignment. Using the classification of Tsukayama et al, 10, 20, and 10 patients had Types I (acute postoperative), II (late chronic), and III (acute hematogenous) infections, respectively. All had surgical débridement and parenteral antibiotics with retention of their existing prostheses. The patients were followed for a minimum of 3 years (range, 36-143 months). Successful implant salvage was achieved in 12 of the 40 patients (30%). However, likelihood of success depended on the type of infection: patients with Type I infections (seven of 10) and patients with Type III infections (five of 10) retained their prostheses more often than patients with Type II infections (zero of 20). We recommend early débridement and retention of the prosthesis with Type I or Type III infections in revised TKAs, but primary removal for Type II infections.

Porps, torps, and homografts in tympanoplasty.

PubMed

Gillanders, D A; Cambon, K G; Doyle, P J

1980-04-01

A brief review of the use of plastique prostheses in ossiculoplasty, as well as the use of homograft tympanic membranes along with our experience is reported. Plastipore prostheses have been found to be useful, and their continued use is advocated. Homograft tympanic membranes are useful in repairing those ears which have undergone extensive damage to the tympanic membrane and ossicles.

Dental claims in the Swedish Patient Insurance Scheme.

PubMed

René, N; Owall, B; Cronström, R

1991-06-01

The Swedish Patient Insurance Scheme covers treatment injuries and guarantees the replacement of failed removable prostheses for 1 year and fixed prostheses for 2 years after fitting. In this paper, 573 dental cases are analysed for a 3-month period in 1986, during which crowns and bridges formed the vast majority of failed treatments that were reported.

Manufacturing Implant Supported Auricular Prostheses by Rapid Prototyping Techniques

PubMed Central

Karatas, Meltem Ozdemir; Cifter, Ebru Demet; Ozenen, Didem Ozdemir; Balik, Ali; Tuncer, Erman Bulent

2011-01-01

Maxillofacial prostheses are usually fabricated on the models obtained following the impression procedures. Disadvantages of conventional impression techniques used in production of facial prosthesis are deformation of soft tissues caused by impression material and disturbance of the patient due to. Additionally production of prosthesis by conventional methods takes longer time. Recently, rapid prototyping techniques have been developed for extraoral prosthesis in order to reduce these disadvantages of conventional methods. Rapid prototyping technique has the potential to simplify the procedure and decrease the laboratory work required. It eliminates the need for measurement impression procedures and preparation of wax model to be performed by prosthodontists themselves In the near future this technology will become a standard for fabricating maxillofacial prostheses. PMID:21912504

Hereditary hemochromatosis as a risk factor for joint replacement surgery.

PubMed

Sahinbegovic, Enijad; Dallos, Tomás; Aigner, Elmar; Axmann, Roland; Engelbrecht, Matthias; Schöniger-Hekele, Maximilian; Karonitsch, Thomas; Farkas, Martin; Karger, Thomas; Willeit, Johann; Stölzel, Ulrich; Keysser, Gernot; Datz, Christian; Kiechl, Stefan; Schett, Georg; Zwerina, Jochen

2010-07-01

Hemochromatosis is an inherited disease with iron overload and joint involvement resembling osteoarthritis. To determine the rate of joint replacement surgery in patients with hemochromatosis, we performed a cross-sectional cohort study. A total of 199 individuals with hereditary hemochromatosis were included. The prevalence of joint replacement surgery in hip, knee, and ankle joints because of secondary osteoarthritis was assessed. Data were compared with 917 healthy subjects from the population-based Bruneck study. A total of 32 of 199 individuals with hemochromatosis received joint replacement surgery with a total number of 52 joints replaced. Compared with expected rates in healthy individuals, patients with hemochromatosis had a significantly higher risk for joint replacement surgery (odds ratio 9.0; confidence interval, 4.6-17.4). Joint replacement occurred significantly earlier in life in patients with hemochromatosis; 21.9% of the patients with hemochromatosis and 1.7% of healthy individuals required joint replacement before the age of 50 years (P=.0027). Moreover, patients with hemochromatosis were more likely to require multiple joint replacements (8.5%) than the control group (expected rate 0.3%; P=.0001). Hemochromatosis is a risk factor for joint replacement surgery because of severe secondary osteoarthritis. Copyright 2010 Elsevier Inc. All rights reserved.

Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021.

PubMed

Kurtz, Steven M; Ong, Kevin L; Lau, Edmund; Bozic, Kevin J

2014-04-16

Few studies have explored the role of the National Health Expenditure and macroeconomics on the utilization of total joint replacement. The economic downturn has raised questions about the sustainability of growth for total joint replacement in the future. Previous projections of total joint replacement demand in the United States were based on data up to 2003 using a statistical methodology that neglected macroeconomic factors, such as the National Health Expenditure. Data from the Nationwide Inpatient Sample (1993 to 2010) were used with United States Census and National Health Expenditure data to quantify historical trends in total joint replacement rates, including the two economic downturns in the 2000s. Primary and revision hip and knee arthroplasty were identified using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification. Projections in total joint replacement were estimated using a regression model incorporating the growth in population and rate of arthroplasties from 1993 to 2010 as a function of age, sex, race, and census region using the National Health Expenditure as the independent variable. The regression model was used in conjunction with government projections of National Health Expenditure from 2011 to 2021 to estimate future arthroplasty rates in subpopulations of the United States and to derive national estimates. The growth trend for the incidence of joint arthroplasty, for the overall United States population as well as for the United States workforce, was insensitive to economic downturns. From 2009 to 2010, the total number of procedures increased by 6.0% for primary total hip arthroplasty, 6.1% for primary total knee arthroplasty, 10.8% for revision total hip arthroplasty, and 13.5% for revision total knee arthroplasty. The National Health Expenditure model projections for primary hip replacement in 2020 were higher than a previously projected model, whereas the current model estimates for total knee arthroplasty were lower. Economic downturns in the 2000s did not substantially influence the national growth trends for hip and knee arthroplasty in the United States. These latest updated projections provide a basis for surgeons, hospitals, payers, and policy makers to plan for the future demand for total joint replacement surgery.