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Sample records for hip spacer implantation

  1. Cement spacer loaded with antibiotics for infected implants of the hip joint.

    PubMed

    Yamamoto, Kengo; Miyagawa, Naoki; Masaoka, Toshinori; Katori, Youichi; Shishido, Takaaki; Imakiire, Atsuhiro

    2009-01-01

    It is difficult to treat infected implants of the hip joints. Such treatment involves immeasurable physical and psychological suffering of the patients. We used antibiotic-impregnated cement spacers in 17 cases of infection after total hip arthroplasty and bipolar arthroplasty with good clinical results. We thoroughly removed any foreign material and formed an antibiotic-impregnated cement spacer into a similar shape as that of the implants. A cement spacer enables high-concentration antibiotics to act on infected sites. Also, it can prevent leg length discrepancy and atrophy of bones or muscles. Although cement spacers have been reported to have problems regarding shape and strength, we achieved good results with a cement spacer mold in the present study. No recurring infection has been found at a mean follow-up period of 3 years and 2 months.

  2. Preventing mechanical complications of hip spacer implantation: technical tips and pearls.

    PubMed

    Barreira, Pedro; Leite, Pedro; Neves, Pedro; Soares, Daniel; Sousa, Ricardo

    2015-06-01

    Periprosthetic joint infection is a frequent complication after total hip replacement. Two-stage exchange with the use of a temporary cement spacer is commonplace. Several complications are possible with its use. In addition to infection persistence, mechanical complications such as dislocation or fractures are among the most common. Several risk factors can and should be addressed during first stage or spacer implantation surgery in order to minimize complications. Technical aspects as well as practical tips and pearls to overcome common nuisances such as spacer instability or femoral and acetabular bone loss will be discussed.

  3. A cement spacer for two-stage revision of infected implants of the hip joint.

    PubMed

    Leunig, M; Chosa, E; Speck, M; Ganz, R

    1998-01-01

    We report the technical details and clinical results of twelve patients who had deep infections of implants in the hip joint and were treated by two-stage revision, using a gentamicin-loaded, hand-moulded cement spacer inserted for the period between resection and reimplantation arthroplasty. During management with the spacer, usually for 4 months, patients were almost free of pain and mobile with good leg control, spending 2/3 of the treatment period at home. Six of twelve spacers failed locally due to dislocation [5] or cement fracture [1], and more than two further episodes of surgery were required in 3 patients. Problems with dislocation of the spacer were significantly higher when the head to neck offset was lacking (P < 0.05) or when anchorage in the femoral shaft was poor. Nevertheless, infection after reimplantation arthroplasty did not occur by the time of follow-up (2.2 years). Based on these data, we consider that the use of the cement spacer is a promising approach to the treatment of complicated infections of the hip joint.

  4. Clinical effectiveness of antibiotic-impregnated cement spacers for the treatment of infected implants of the hip joint.

    PubMed

    Yamamoto, Kengo; Miyagawa, Naoki; Masaoka, Toshinori; Katori, Yoichi; Shishido, Takaaki; Imakiire, Atsuhiro

    2003-01-01

    It is difficult to treat an infected implant of the hip joints, as it requires long-term treatment and eventually may lead to amputation or arthrodesis, involving immeasurable physical and psychological suffering for the patient. We utilized antibiotic-impregnated cement spacers for 17 infections after total hip arthroplasty and bipolar arthroplasty with good clinical results. We thoroughly removed any foreign material and formed an antibiotic-impregnated cement spacer into a shape similar to that of the implants. This enabled high-concentration antibiotics to act on the infected sites. It also can prevent leg-length discrepancy and atrophy of bones or muscles. Although cement spacers have been reported to have problems regarding shape and strength, we achieved good results with cement spacer molds in the present study. All revision surgeries were performed using a two-stage procedure. No infection has recurred at a mean follow-up of 3 years 2 months.

  5. Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study

    PubMed Central

    2011-01-01

    Background Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol. Methods Nineteen patients (20 hips) were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS]) and hip joint function (Harris Hip score). Results The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104) months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84) pre-operatively to 18 (range, 0 - 38) prior to spacer removal and to 8 (range, 0 - 15) at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment. Conclusions Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies. PMID:21575241

  6. Hip Implant Systems

    MedlinePlus

    ... Medical Devices Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants Hip Implants Share ... femoral head) is removed and replaced with a prosthetic ball made of metal or ceramic, and the ...

  7. Titanium-copper-nitride coated spacers for two-stage revision of infected total hip endoprostheses.

    PubMed

    Ellenrieder, Martin; Haenle, Maximilian; Lenz, Robert; Bader, Rainer; Mittelmeier, Wolfram

    2011-01-01

    Within the first two years after total hip arthroplasty implant-associated infection has become the second most common reason for a revision surgery. Two-stage implant exchange is frequently conducted using temporary spacers made of antibiotic-loaded cement in order to prevent a bacterial colonization on the spacer. Avoiding several disadvantages of cement spacers, a conventional hemi-endoprosthesis was equipped with a copper-containing implant coating for inhibition of bacterial biofilms. In the present paper details of this novel treatment concept are presented including a case report.

  8. Titanium-copper-nitride coated spacers for two-stage revision of infected total hip endoprostheses

    PubMed Central

    Ellenrieder, Martin; Haenle, Maximilian; Lenz, Robert; Bader, Rainer; Mittelmeier, Wolfram

    2011-01-01

    Within the first two years after total hip arthroplasty implant-associated infection has become the second most common reason for a revision surgery. Two-stage implant exchange is frequently conducted using temporary spacers made of antibiotic-loaded cement in order to prevent a bacterial colonization on the spacer. Avoiding several disadvantages of cement spacers, a conventional hemi-endoprosthesis was equipped with a copper-containing implant coating for inhibition of bacterial biofilms. In the present paper details of this novel treatment concept are presented including a case report. PMID:22242097

  9. Investigations on the wear behaviour of the temporary PMMA-based hip Spacer-G.

    PubMed

    Affatato, S; Mattarozzi, A; Taddei, P; Robotti, P; Soffiatti, R; Sudanese, A; Toni, A

    2003-01-01

    Total hip replacement has become one of the most successful orthopaedic procedures. However, complications due to infections may give serious problems and have devastating consequences for the hip implant. The use of a temporary three-dimensional polymethylmethacrylate (PMMA) cement spacer may be an alternative to solve infections in hip implants, improving the lives of patients awaiting reimplantation. In order to evaluate their wear behaviour, five PMMA Spacer-G femoral heads were tested against five post-mortem pelves in a hip joint simulator with bovine calf serum as lubricant. The surface of the worn spacers was characterized by scanning electron microscopy (SEM) analysis; all the samples revealed a similar morphology, showing areas characterized by different degrees of wear. Particle debris was isolated from the lubricant and PMMA particles and bone fractions were quantified. The amount of debris was found to be higher than where no-temporary prostheses were used. However, this result is acceptable since wear debris is removed by lavage irrigation when the Spacer-G is explanted. On the basis of these data, it is considered that the use of the cement Spacer-G could be a promising approach to the treatment of complicated infections of the hip joint. Therefore, Spacer-G is worthy of further research.

  10. Treatment of an old infection in a total hip replacement with an interim spacer prosthesis.

    PubMed

    Zilkens, K W; Casser, H R; Ohnsorge, J

    1990-01-01

    When treating a septic hip-joint prosthesis with bone loss of the proximal femur secondary to osteomyelitis, we implanted a specially designed prosthesis to act as a local antibiotic and spacer between the acetabulum and femur until the infection abated. Arthroplasty could then be carried out with no trouble and there was no recurrence of infection.

  11. Two-stage revision of hip prosthesis infection using a hip spacer with stabilising proximal cementation.

    PubMed

    Gil Gonzalez, Sergi; Marqués López, Fernando; Rigol Ramon, Pau; Mestre Cortadellas, Carlos; Cáceres Palou, Enric; León García, Alfonso

    2010-01-01

    Two-stage revision hip arthroplasty for infection using an antibiotic-loaded cement spacer has been used frequently with good results. However, spacer instability is also frequent. Proximal cementation of the spacer could avoid spacer dislocation. We retrospectively assessed 35 patients in whom a 2-stage revision hip arthroplasty for infection was carried out using an antibiotic-loaded cement spacer with gentamicin (Spacer-G) in which the spacer was proximally cemented in 16 patients. The mean follow-up was 32 months. We assessed spacer stability and infection elimination. There were 8 spacer dislocations (22.9%), 5 in hips without proximal cementation and 2 in hips with proximal cementation (p>0.05). There was no fracture in any hip. Reinfection occurred in 5 hips (14.3%), in 3 with the same microorganism, while 2 had a different microorganism. Our results indicate that the proximal cementation of the spacer prevents its dislocation. Infection was eliminated in 86% of the hips.

  12. Two-Stage Revision Total Hip Arthroplasty for Periprosthetic Infections Using Antibiotic-Impregnated Cement Spacers of Various Types and Materials

    PubMed Central

    Takahira, Naonobu; Moriya, Mitsutoshi; Yamamoto, Takeaki; Minegishi, Yojiro; Sakai, Rina; Itoman, Moritoshi; Takaso, Masashi

    2013-01-01

    Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or α-tricalcium phosphate (α-TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, α-TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation. PMID:24381509

  13. Radiographic evaluation of hip implants.

    PubMed

    Chang, Connie Y; Huang, Ambrose J; Palmer, William E

    2015-02-01

    Serial radiographs are the mainstay in the longitudinal assessment of hip implants. The prosthesis, periprosthetic bone, and juxta-articular soft tissues are inspected for fracture, periosteal reaction, stress shielding, calcar resorption, osteolysis, bony remodeling, metallic debris, and heterotopic ossification. Comparison radiographs best confirm implant migration, subsidence, and aseptic loosening. Infection, particle disease, reaction to metal, and mechanical impingement are important causes of postsurgical pain, but in their earliest stages they may be difficult to diagnose using radiographs. This article addresses the role of radiography following hip arthroplasty. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  14. Burnishing Techniques Strengthen Hip Implants

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In the late 1990s, Lambda Research Inc., of Cincinnati, Ohio, received Small Business Innovation Research (SBIR) awards from Glenn Research Center to demonstrate low plasticity burnishing (LPB) on metal engine components. By producing a thermally stable deep layer of compressive residual stress, LPB significantly strengthened turbine alloys. After Lambda patented the process, the Federal Aviation Administration accepted LPB for repair and alteration of commercial aircraft components, the U.S. Department of Energy found LPB suitable for treating nuclear waste containers at Yucca Mountain. Data from the U.S. Food and Drug Administration confirmed LPB to completely eliminate the occurrence of fretting fatigue failures in modular hip implants.

  15. Implant Design in Cementless Hip Arthroplasty

    PubMed Central

    Kim, Jung Taek

    2016-01-01

    When performing cementless hip arthroplasty, it is critical to achieve firm primary mechanical stability followed by biological fixation. In order to achieve this, it is essential to fully understand characteristics of implant design. In this review, the authors review fixation principles for a variety of implants used for cementless hip replacement and considerations for making an optimal selection. PMID:27536647

  16. A Hip Implant Energy Harvester

    NASA Astrophysics Data System (ADS)

    Pancharoen, K.; Zhu, D.; Beeby, S. P.

    2014-11-01

    This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 μW was achieved with an optimum resistive load of 250Ω.

  17. RELEASE OF GENTAMICIN FROM CEMENT SPACERS IN TWO-STAGE PROCEDURES FOR HIP AND KNEE PROSTHETIC INFECTION: AN IN VIVO PHARMACOKINETIC STUDY WITH CLINICAL FOLLOW-UP.

    PubMed

    Balato, G; Ascione, T; Rosa, D; Pagliano, P; Solarino, G; Moretti, B; Mariconda, M

    2015-01-01

    Eighteen patients undergoing two-stage exchange arthroplasty for infected total hip or knee arthroplasty using gentamicin-loaded bone cement spacers (80g bone cement, 2 g gentamicin and 2 g clindamycin) were studied. The concentration of gentamicin eluted from the spacers was assessed on samples of blood, urine, and drainage fluid that were collected from each patient at set intervals during the 48 hours following the first-stage surgery. The hip and knee cement spacers showed similar curve of release over the first postoperative hours (early peak followed by slow release), but the mean gentamicin concentration in the drainage fluid was higher in patients with hip spacers compared to patients with knee spacers (30.61±19.47 mg/L vs 17.43±13,63 mg/L, p less than 0.05). In patients with hip spacers, the mean, maximum, and minimum concentration of gentamicin was higher with respect to the minimum inhibitory concentration (MIC) break point for Staphylococcus spp, Pseudomonas Aeruginosa and Enterobacteriaceae throughout the first postoperative 48 h. Conversely, in 25% of patients with a knee spacer a drug concentration below the MIC break point for Gram negative bacteria was found in the drainage fluid after 12 h. Gentamicin levels in the blood samples were negligible over the entire time interval and were steadily well below the renal toxicity reference. The highest urinary concentration of gentamicin was observed between 4 and 9 h postoperatively. Subsequently, it gradually declined until 48 h. Clinically, the rate of cure was 100% at a mean follow-up of 113 weeks (range 90-182). Gentamicin-loaded cement spacers offer the advantage of achieving early high concentrations of the antibiotic directly at the site of infection but especially in the knee a systemic antibiotic therapy must be given as a complement to the spacer implantation to eradicate periprosthetic joint infection (PJI).

  18. In vitro release of antibiotics from commercial PMMA beads and articulating hip spacers.

    PubMed

    Moojen, Dirk Jan F; Hentenaar, Bram; Charles Vogely, H; Verbout, Abraham J; Castelein, René M; Dhert, Wouter J A

    2008-12-01

    The efficacy and benefits of high-dose antibiotic cement spacers compared with beads in the treatment of an infected prosthesis have been shown. However, in clinical practice, commercial, low-dose antibiotic bone cement is often used. This study investigated the in vitro antibiotic release of hip spacers made from Refobacin-Palacos-R or Antibiotic-Simplex-P cement compared with Septopal beads. Antibiotic concentrations were measured during 6 weeks. All carriers showed a burst release, but spacers showed little additional release after the first week. Cumulative release was 27.5 +/- 2.3 mg for Palacos, 23.8 +/- 0.2 mg for Simplex, and 188.3 +/- 9.3 mg for Septopal (P < .001). Despite the efficacy of high-dose antibiotic bone cement spacers, we believe one should be cautious toward using low-dose antibiotic bone cement for spacers because this could result in an unsuccessful eradication of infection.

  19. Standardized Loads Acting in Hip Implants

    PubMed Central

    Bergmann, Georg; Bender, Alwina; Dymke, Jörn; Duda, Georg; Damm, Philipp

    2016-01-01

    With the increasing success of hip joint replacements, the average age of patients has decreased, patients have become more active and their expectations of the implant durability have risen. Thus, pre-clinical endurance tests on hip implants require defining realistic in vivo loads from younger and more active patients. These loads require simplifications to be applicable for simulator tests and numerical analyses. Here, the contact forces in the joint were measured with instrumented hip implants in ten subjects during nine of the most physically demanding and frequent activities of daily living. Typical levels and directions of average and high joint loads were extracted from the intra- and inter-individually widely varying individual data. These data can also be used to analyse bone remodelling at the implant-bone interface, evaluate tissue straining in finite element studies or validate analytical loading predictions, among other uses. The current ISO standards for endurance tests of implant stems and necks are based on historic analytical data from the 1970s. Comparisons of these test forces with in vivo loads unveiled that their unidirectional orientations deviate from the time-dependent in vivo directions during walking and most other activities. The ISO force for testing the stem is substantially too low while the ISO force for the neck better matches typical in vivo magnitudes. Because the magnitudes and orientations of peak forces substantially vary among the activities, load scenarios that reflect a collection of time-dependent high forces should be applied rather than using unidirectional forces. Based on data from ten patients, proposals for the most demanding activities, the time courses of the contact forces and the required cycle numbers for testing are given here. Friction moments in the joint were measured in addition to the contact forces. The moment data were also standardized and can be applied to wear tests of the implant. It was shown that

  20. Acetabular spacers in 2-stage hip revision: is it worth it? A single-centre retrospective study.

    PubMed

    Burastero, Giorgio; Basso, Marco; Carrega, Giuliana; Cavagnaro, Luca; Chiarlone, Francesco; Salomone, Carlo; Papa, Gabriele; Felli, Lamberto

    2017-03-31

    The aim of this work is to evaluate an acetabular antibiotic loaded bone cement spacer in 2-stage revision surgery as a potential approach able to reduce complications during the inter-stage period (i.e. dislocation, acetabular wear), as well as simplify 2-stage hip revision surgery and improve hip biomechanics. We performed a retrospective comparative study and evaluated clinical, radiological and surgical data of 71 patients affected by periprosthetic hip infection who were treated with 2-stage exchange. 31 patients were treated using an acetabular spacer in addition to the femoral (group A) while 40 underwent a standard revision surgery (femoral spacer only, group B). Mean time of surgery for the first stage was 148 ± 59 minutes and 142 ± 45 minutes for group A and B respectively; we noted a statistically significant reduction (26 min, p = 0.015) in the same parameter for the second stage (83 ± 35 minutes for group A and 109 ± 36 minutes for group B). We observed the following interstage complications: 5 femoral spacer dislocations (1 for group A and 4 for group B); 1 spacer fracture (group B), 1 spacer fracture (group A), 2 periprosthetic fractures (group B) and 2 patients with acetabular spacer instability (group B). Additionally, we observed a significant improvement in leg length restoration for group A (p = 0.03). Our data show that the acetabular spacer technique is able to reduce the interstage complication rate and allow improved hip biomechanics restoration.

  1. Hip Implant Modified To Increase Probability Of Retention

    NASA Technical Reports Server (NTRS)

    Canabal, Francisco, III

    1995-01-01

    Modification in design of hip implant proposed to increase likelihood of retention of implant in femur after hip-repair surgery. Decreases likelihood of patient distress and expense associated with repetition of surgery after failed implant procedure. Intended to provide more favorable flow of cement used to bind implant in proximal extreme end of femur, reducing structural flaws causing early failure of implant/femur joint.

  2. Personalized hip implants manufacturing and testing

    NASA Astrophysics Data System (ADS)

    Croitoru, A. Sorin Mihai; Pacioga, B. Adrian; Comsa, C. Stanca

    2017-09-01

    Two models of Ti6Al4V personalized femoral stems for hip replacement have been designed and laser sintered with different sizes of fenestrated architecture that mimics the natural structure of bone, ensuring postoperative bone ingrowth and increasing the elasticity of the entire structure. They were tested statically and dynamically versus a commercial femoral stem. Mechanical tests were performed in order to determine the fatigue limit using the Locati method. The tests were conducted in a thermostatic bath (37°±1°) with the implants immersed in distilled water salted solution 0.91%. For probe embedment poly-methyl methacrylate (PMMA) was used. The characteristic curves of the two personalized fenestrated implants reveal an elastic behaviour by their nonlinear appearance. After dynamic tests an inverse relationship between displacements obtained in the static tests and the fatigue limit was observed. Large fenestrations conferred the desired elasticity to the implant, but contributed to a life service reduction. The fatigue limit for both implants was much above the minimum value specified by ISO 7602: 2010, so both models can be safely used in the medical practice, leading to increased life service of implants.

  3. "Reverse" hip spacer for massive distal femur defects in peri-prosthetic knee infections.

    PubMed

    Flores, X; Vicente, M; Haddad, S; Amat, C; Carrera, L; Corona, P S

    Bone loss in the distal femur is a common problem in knee revision surgeries. The problem is exacerbated in the context of an active infection. In extreme cases this bone loss could compromise the feasibility of a two-stage exchange protocol using dynamic spacers due to the inherent instability of this type of spacers. Use of a hip prefabricated spacer in a "reverse" way forming a ball-and- socket joint is a therapeutic option in cases of massive bone defect and infection. A retrospective review was performed of our institutional database to identify all cases of massive distal femoral defect in which this technique was used from January 2010 to December 2013. A record was made of the epidemiological data, characteristics of the infection (clinical and microbiological), and adverse event during the spacer stage. The main end-point was the infection eradication rate (minimum: 18 months of follow-up). The complications associated with the technique were also assessed. Finally, each patient completed a visual analogue pain scale, and a satisfaction questionnaire (SAPS). This technique was successfully used in six cases so far, controlling the infection in all cases. Mean femoral defect was 117cm (range: 32-191cm). Mean time with spacer was 7.6 months, with no major complications. All but one patient reached second stage reconstruction with a mega-prosthesis, and mean time since second stage was 34.7 months. All patients stated high levels of satisfaction with the technique employed, as well as and low pain scores (mean visual analogue pain scale: 1; range: 0-4). A reproducible and safe technique is described. Patients report a high level of satisfaction with the procedure, and there were no cases of recurrence of the infection after a minimum follow-up of 18 months. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. A preliminary biomechanical study of a novel carbon-fibre hip implant versus standard metallic hip implants.

    PubMed

    Bougherara, Habiba; Zdero, Rad; Dubov, Anton; Shah, Suraj; Khurshid, Shaheen; Schemitsch, Emil H

    2011-01-01

    Total hip arthroplasty is a widespread surgical approach for treating severe osteoarthritis of the human hip. Aseptic loosening of standard metallic hip implants due to stress shielding and bone loss has motivated the development of new materials for hip prostheses. Numerically, a three-dimensional finite element (FE) model that mimicked hip implants was used to compare a new hip stem to two commercially available implants. The hip implants simulated were a novel CF/PA12 carbon-fibre polyamide-based composite hip stem, the Exeter hip stem (Stryker, Mahwah, NJ, USA), and the Omnifit Eon (Stryker, Mahwah, NJ, USA). A virtual axial load of 3 kN was applied to the FE model. Strain and stress distributions were computed. Experimentally, the three hip stems had their distal portions rigidly mounted and had strain gauges placed along the surface at 3 medial and 3 lateral locations. Axial loads of 3 kN were applied. Measurements of axial stiffness and strain were taken and compared to FE analysis. The overall linear correlation between FE model versus experimental strains showed reasonable results for the lines-of-best-fit for the Composite (Pearson R(2)=0.69, slope=0.82), Exeter (Pearson R(2)=0.78, slope=0.59), and Omnifit (Pearson R(2)=0.66, slope=0.45), with some divergence for the most distal strain locations. From FE analysis, the von Mises stress range for the Composite stem was much lower than that in the Omnifit and Exeter implants by 200% and 45%, respectively. The preliminary experiments showed that the Composite stem stiffness (1982 N/mm) was lower than the metallic hip stem stiffnesses (Exeter, 2460 N/mm; Omnifit, 2543 N/mm). This is the first assessment of stress, strain, and stiffness of the CF/PA12 carbon-fibre hip stem compared to standard commercially-available devices.

  5. Mechanical evaluation of hip cement spacer reinforcement with stainless steel Kirschner wires, titanium and carbon rods, and stainless steel mesh.

    PubMed

    Kaku, Nobuhiro; Tabata, Tomonori; Tsumura, Hiroshi

    2015-04-01

    In two-stage treatments for infections after total hip arthroplasty, antibiotic-loaded cement spacers help treat the infection by antibiotic elution and prevent contraction. However, such spacers are weak and may fracture while awaiting replacement, impairing functionality. We evaluated whether a Kirschner wire (K-wire) mounted into the spacer reinforced its strength along with the effects of the reinforcing material, position, and intensity. Spacers without reinforcing materials constituted the control group. As reinforcing materials, stainless steel K-wires (diameters 3 and 6 mm), titanium alloy and carbon fibers (diameter 3.175 mm), and stainless steel meshes (inner and outer diameters, 6 and 9 mm, respectively) were inserted into the spacer mold before filling with cement. The spacers complied with ISO 7206-4; a compressive load was applied using a testing machine with a velocity of 25.4 mm/min, and the maximum load was recorded. We used 1-3 K-wires positioned on the medial side, lateral side, neck only, and stem only and tested 3 specimens for each condition. The control group withstood the highest load. Stainless steel was the strongest material; 3-mm K-wires in the neck and lateral side withstood a higher load. The computed tomography (CT) imaging revealed a cavity between the K-wires and cement. When K-wires were inserted along the whole length, despite cement fractures, continuity was maintained because of the reinforcing materials. It is difficult to improve the reinforcing strength of spacers using K-wires; however, K-wires prevented dislocation of cement spacer fragments, which can help prevent contraction and facilitate spacer removal during replacement.

  6. Controlling the Biomimetic Implant Interface: Modulating Antimicrobial Activity by Spacer Design

    NASA Astrophysics Data System (ADS)

    Wisdom, Cate; Vanoosten, Sarah Kay; Boone, Kyle W.; Khvostenko, Dmytro; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2016-08-01

    Surgical site infection is a common cause of post-operative morbidity, often leading to implant loosening, ultimately requiring revision surgery, increased costs and worse surgical outcomes. Since implant failure starts at the implant surface, creating and controlling the bio-material interface will play a critical role in reducing infection while improving host cell-to-implant interaction. Here, we engineered a biomimetic interface based upon a chimeric peptide that incorporates a titanium binding peptide (TiBP) with an antimicrobial peptide (AMP) into a single molecule to direct binding to the implant surface and deliver an antimicrobial activity against S. mutans and S. epidermidis, two bacteria which are linked with clinical implant infections. To optimize antimicrobial activity, we investigated the design of the spacer domain separating the two functional domains of the chimeric peptide. Lengthening and changing the amino acid composition of the spacer resulted in an improvement of minimum inhibitory concentration by a three-fold against S. mutans. Surfaces coated with the chimeric peptide reduced dramatically the number of bacteria, with up to a nine-fold reduction for S. mutans and a 48-fold reduction for S. epidermidis. Ab initio predictions of antimicrobial activity based on structural features were confirmed. Host cell attachment and viability at the biomimetic interface were also improved compared to the untreated implant surface. Biomimetic interfaces formed with this chimeric peptide offer interminable potential by coupling antimicrobial and improved host cell responses to implantable titanium materials, and this peptide based approach can be extended to various biomaterials surfaces.

  7. Hip resurfacing arthroplasty complicated by mismatched implant components

    PubMed Central

    Calistri, Alessandro; Campbell, Patricia; Van Der Straeten, Catherine; De Smet, Koen Aimè

    2017-01-01

    Metal-on-metal hip resurfacing has gained popularity as a feasible treatment option for young and active patients with hip osteoarthritis and high functional expectations. This procedure should only be performed by surgeons who have trained specifically in this technique. Preoperative planning is essential for hip resurfacing in order to execute a successful operation and preview any technical problems. The authors present a case of a man who underwent a resurfacing arthroplasty for osteoarthritis of the left hip that was complicated by mismatched implant components that were revised three days afterwards for severe pain and leg length discrepancy. Such mistakes, although rare, can be prevented by educating operating room staff in the size and colour code tables provided by the companies on their prostheses or implant boxes. PMID:28361022

  8. Hip resurfacing arthroplasty complicated by mismatched implant components.

    PubMed

    Calistri, Alessandro; Campbell, Patricia; Van Der Straeten, Catherine; De Smet, Koen Aimè

    2017-03-18

    Metal-on-metal hip resurfacing has gained popularity as a feasible treatment option for young and active patients with hip osteoarthritis and high functional expectations. This procedure should only be performed by surgeons who have trained specifically in this technique. Preoperative planning is essential for hip resurfacing in order to execute a successful operation and preview any technical problems. The authors present a case of a man who underwent a resurfacing arthroplasty for osteoarthritis of the left hip that was complicated by mismatched implant components that were revised three days afterwards for severe pain and leg length discrepancy. Such mistakes, although rare, can be prevented by educating operating room staff in the size and colour code tables provided by the companies on their prostheses or implant boxes.

  9. Muscle atrophy and metal-on-metal hip implants

    PubMed Central

    Berber, Reshid; Khoo, Michael; Cook, Erica; Guppy, Andrew; Hua, Jia; Miles, Jonathan; Carrington, Richard; Skinner, John; Hart, Alister

    2015-01-01

    Background and purpose Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. Patients and methods We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23–83) years. The median time post-implantation was 83 (35–142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. Results The median blood cobalt was 6.84 (0.24–90) ppb and median chromium level was 4.42 (0.20–45) ppb. The median Oxford hip score was 34 (5–48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). Interpretation Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs. PMID:25588091

  10. Status of surface modification techniques for artificial hip implants

    PubMed Central

    Ghosh, Subir; Abanteriba, Sylvester

    2016-01-01

    Abstract Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce the friction and wear of artificial implants. This article reviews the status of the developments of surface modification techniques and their effects on commonly used artificial joint implants. This study focused only on artificial hip joint prostheses research of the last 10 years. A total of 27 articles were critically reviewed and categorized according to surface modification technique. The literature reveals that modified surfaces exhibit reduced friction and enhanced wear resistance of the contact surfaces. However, the wear rates are still noticeable in case of surface texturing and surface coating. The associated vortex flow aids to release entrapped wear debris and thus increase the wear particles generation in case of textured surfaces. The earlier delamination of coating materials due to poor adhesion and graphitization transformation has limited the use of coating techniques. Moreover, the produced wear debris has adverse effects on biological fluid. Conversely, the surface grafting technique provides phospholipid like layer that exhibited lower friction and almost zero wear rates even after a longer period of friction and wear test. The findings suggest that further investigations are required to identify the role of surface grafting on film formation and heat resistance ability under physiological hip joint conditions for improved performance and longevity of hip implants. PMID:28228866

  11. Status of surface modification techniques for artificial hip implants.

    PubMed

    Ghosh, Subir; Abanteriba, Sylvester

    2016-01-01

    Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce the friction and wear of artificial implants. This article reviews the status of the developments of surface modification techniques and their effects on commonly used artificial joint implants. This study focused only on artificial hip joint prostheses research of the last 10 years. A total of 27 articles were critically reviewed and categorized according to surface modification technique. The literature reveals that modified surfaces exhibit reduced friction and enhanced wear resistance of the contact surfaces. However, the wear rates are still noticeable in case of surface texturing and surface coating. The associated vortex flow aids to release entrapped wear debris and thus increase the wear particles generation in case of textured surfaces. The earlier delamination of coating materials due to poor adhesion and graphitization transformation has limited the use of coating techniques. Moreover, the produced wear debris has adverse effects on biological fluid. Conversely, the surface grafting technique provides phospholipid like layer that exhibited lower friction and almost zero wear rates even after a longer period of friction and wear test. The findings suggest that further investigations are required to identify the role of surface grafting on film formation and heat resistance ability under physiological hip joint conditions for improved performance and longevity of hip implants.

  12. Optimal design of composite hip implants using NASA technology

    NASA Technical Reports Server (NTRS)

    Blake, T. A.; Saravanos, D. A.; Davy, D. T.; Waters, S. A.; Hopkins, D. A.

    1993-01-01

    Using an adaptation of NASA software, we have investigated the use of numerical optimization techniques for the shape and material optimization of fiber composite hip implants. The original NASA inhouse codes, were originally developed for the optimization of aerospace structures. The adapted code, which was called OPORIM, couples numerical optimization algorithms with finite element analysis and composite laminate theory to perform design optimization using both shape and material design variables. The external and internal geometry of the implant and the surrounding bone is described with quintic spline curves. This geometric representation is then used to create an equivalent 2-D finite element model of the structure. Using laminate theory and the 3-D geometric information, equivalent stiffnesses are generated for each element of the 2-D finite element model, so that the 3-D stiffness of the structure can be approximated. The geometric information to construct the model of the femur was obtained from a CT scan. A variety of test cases were examined, incorporating several implant constructions and design variable sets. Typically the code was able to produce optimized shape and/or material parameters which substantially reduced stress concentrations in the bone adjacent of the implant. The results indicate that this technology can provide meaningful insight into the design of fiber composite hip implants.

  13. Saving Implants BMP-2 Application in Revision Total Hip Surgery.

    PubMed

    Jäger, M; Emami, R; Thorey, F; Krauspe, R

    2006-06-01

    Besides others, there are two major problems in total hip replacement surgery which result in implant failure. First there is aseptic loosening due to a lack of implant biocompatibility or micromovements and second periimplant wear debris induced osteolysis which limits the survival rate of an implant. Regarding to recent data there are only limited therapeutic strategies to heal these bony defects without arthroplasty revision surgery. Since the investigation and characterization of adult mesenchymal stem cells (MSCs) from bone marrow, a cell and tissue engineering based therapy might be a promising solution to heal endoprosthesis associated bony defects. Moreover the application of growth factors in bone reconstructive surgery is another treatment concept to promote local bone regeneration. We report about a 73-year old patient with a painful weight bearing and a large, wear debris induced pelvic osteolysis after total hip arthroplasty. To prevent from salvage surgical procedures and preserve bone, a healing attempted was performed by filling the critical bony defect zone with a BMP-2/MSC composit. Clinical and radiological follow-ups showed a progressive bony healing of the critical size defect area without any complications. Fifteen months after application the patient is still pain free, has no limitations in daily life or sport activities. The case embarks on a strategy of non-embryonic stem cell and growth factor application to heal bony defects at patients with total hip endoprosthesis.

  14. Design Considerations for the Next Generation Hip Resurfacing Implant: Commentary.

    PubMed

    Su, Edwin P

    2017-02-01

    The current generation of hip resurfacing consists of a metal-on-metal ball and monoblock socket of minimal thickness. Although results in certain patient subgroups have been excellent at up to 15 years of follow-up, other subgroups have had poor results. The hard-on-hard bearing is susceptible to edge-loading conditions and may produce excessive metallic debris; furthermore, other patients have had allergic reactions to the metal byproducts. In both situations, there can be clinical failures from adverse local tissue reactions. As such, the role of hip resurfacing has diminished over the last decade because of these issues. Developing the next generation hip resurfacing is essential to address these problems, and there are multiple design considerations in doing so. The choice of materials will be of prime concern, with the decision to use a hard-on-soft or hard-on-hard articulation. The dimensions of the resurfacing implant also pose a challenge, because of the requirement to preserve the bone. Fixation of the implant is another area of interest, in order to maximize implant longevity.

  15. Improvement of the reliability of ceramic hip joint implants.

    PubMed

    Weisse, Bernhard; Zahner, Marcel; Weber, W; Rieger, W

    2003-11-01

    The aim of this article is to present the optimization of a proof test procedure of ceramic hip joint ball heads. The proof test rejects defective samples in the production line before being implanted into human body. Thereby on every ceramic ball head a static load is applied, which is somewhat higher than the maximum physiological load. The magnitude of the applied load should not damage the samples which are free of flaws in the high stress area. The configuration of the proof test influences the stress distribution in the ball head, which should be similar to the physiological case. To determine the stress distribution, a non-linear finite element (FE) analysis was performed and the results were validated by measurements. With an iterative approach based on FE calculations the proof test configuration was optimized in such a way that the stress distribution in the ball head is similar to the stress distribution in vivo. In this study all ball heads showed very high fatigue resistance after being proof tested and fulfilled the requirements of the FDA (Food and Drug Administration, USA) described in the Guidance Document for the Preparation of Premarket Notifications for Ceramic Ball Hip System. The probability of a fracture of an implanted ceramic ball head can be decreased by the presented optimized proof test procedure. Latter can thus improve the reliability of ceramic hip joint ball heads. The study was supported by the KTI (Commission for Technology and Innovation, Switzerland).

  16. Antibiotic Spacer Arthroplasty for Revision MTP Arthrodesis: A Novel Means to Build the Implant: A Case Report

    PubMed Central

    Bitterman, Adam; Patel, Milap; Gurtowski, James P

    2016-01-01

    Metatarsophalangeal (MTP) joint osteoarthritis (OA), also known as hallux rigidus (HR), is the most common degenerative arthropathy of the foot and is often the result of trauma. There are multiple methods of addressing the patient’s pain and limited function. Arthrodesis is the gold standard to manage severe MTP arthritis with a highly significant union rate. With various techniques of arthrodesis available, ranging from cannulated screw fixation, Kirschner wires, as well as plate and screw fixation, the orthopedic surgeon has multiple modalities to address this ailment; however, when these fail due to infection, the armament is limited. Through the idea of articulating antibiotic spacers in other regions of the body such as the knee and hip, we present a novel technique to the creation of an antibiotic spacer in the setting of a failed infected MTP arthrodesis.  PMID:27114892

  17. Antibiotic Spacer Arthroplasty for Revision MTP Arthrodesis: A Novel Means to Build the Implant: A Case Report.

    PubMed

    Bitterman, Adam; Mathew, Cristin; Patel, Milap; Gurtowski, James P

    2016-03-21

    Metatarsophalangeal (MTP) joint osteoarthritis (OA), also known as hallux rigidus (HR), is the most common degenerative arthropathy of the foot and is often the result of trauma. There are multiple methods of addressing the patient's pain and limited function. Arthrodesis is the gold standard to manage severe MTP arthritis with a highly significant union rate. With various techniques of arthrodesis available, ranging from cannulated screw fixation, Kirschner wires, as well as plate and screw fixation, the orthopedic surgeon has multiple modalities to address this ailment; however, when these fail due to infection, the armament is limited. Through the idea of articulating antibiotic spacers in other regions of the body such as the knee and hip, we present a novel technique to the creation of an antibiotic spacer in the setting of a failed infected MTP arthrodesis.

  18. Revision total hip arthroplasty: the femoral side using cemented implants.

    PubMed

    Holt, Graeme; Hook, Samantha; Hubble, Matthew

    2011-02-01

    Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures.

  19. Revision total hip arthroplasty: the femoral side using cemented implants

    PubMed Central

    Hook, Samantha; Hubble, Matthew

    2010-01-01

    Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures. PMID:21165618

  20. Temporary total hip arthroplasty-like spacer for treating an infected periprosthetic femoral fracture using a long stem: A case report.

    PubMed

    Kim, Youngwoo; Katsura, Yoshiaki; Kasahara, Nina; Kasahara, Takashi; Kanamura, Masashi; Kawanabe, Keiichi

    2017-01-01

    Infected periprosthetic femoral fractures are among the most complex and significant complications of total hip arthroplasty (THA). We report the novel use of a temporary THA-like spacer for treating an infected periprosthetic femoral fracture after revision surgery using a long stem. We present a 72-year-old woman sustained a left infected periprosthetic femoral fracture after revi - streptococci in the culture sample. On suspicion of a periprosthetic joint infection, we planned a two-stage procedure. We used a temporary THA-like spacer comprising the removed femoral long stem, which was autoclaved and then reimplanted, and applied a new polyethylene acetabular liner. Both components were cemented in place with antibioticloaded bone cement, without applying strong pressure. Pain control waseasily achieved postoperatively because the fracture had been stabilized early. The THA-like spacer was stable, and allowed a good range of motion without pain. She was allowed to move with a wheelchair and was walk with partial weight bearing without pain. Seven week after the initial THAlike spacer placement, we performed a revision THA after successful control of infection. At the 1-year follow-up, the patient remained free of infection. Temporary antibiotic-loaded cement-coated THA-like spacer using a long stem facilitated the eradication of infection, fracture stabilization, and enables partial weight bearing without pain. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  1. The lubrication performance of the ceramic-on-ceramic hip implant under starved conditions

    PubMed Central

    Meng, Qingen; Wang, Jing; Yang, Peiran; Jin, Zhongmin; Fisher, John

    2015-01-01

    Lubrication plays an important role in the clinical performance of the ceramic-on-ceramic (CoC) hip implant in terms of reducing wear and avoiding squeaking. All the previous lubrication analyses of CoC hip implants assumed that synovial fluid was sufficiently supplied to the contact area. The aim of this study was to investigate the lubrication performance of the CoC hip implant under starved conditions. A starved lubrication model was presented for the CoC hip implant. The model was solved using multi-grid techniques. Results showed that the fluid film thickness of the CoC hip implant was affected by fluid supply conditions: with the increase in the supplied fluid layer, the lubrication film thickness approached to that of the fully blooded solution; when the available fluid layer reduced to some level, the fluid film thickness considerably decreased with the supplying condition. The above finding provides new insights into the lubrication performance of hip implants. PMID:26114217

  2. The lubrication performance of the ceramic-on-ceramic hip implant under starved conditions.

    PubMed

    Meng, Qingen; Wang, Jing; Yang, Peiran; Jin, Zhongmin; Fisher, John

    2015-10-01

    Lubrication plays an important role in the clinical performance of the ceramic-on-ceramic (CoC) hip implant in terms of reducing wear and avoiding squeaking. All the previous lubrication analyses of CoC hip implants assumed that synovial fluid was sufficiently supplied to the contact area. The aim of this study was to investigate the lubrication performance of the CoC hip implant under starved conditions. A starved lubrication model was presented for the CoC hip implant. The model was solved using multi-grid techniques. Results showed that the fluid film thickness of the CoC hip implant was affected by fluid supply conditions: with the increase in the supplied fluid layer, the lubrication film thickness approached to that of the fully blooded solution; when the available fluid layer reduced to some level, the fluid film thickness considerably decreased with the supplying condition. The above finding provides new insights into the lubrication performance of hip implants. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Finding the right hip implant for patient and surgeon: the Dutch strategy--empowering patients.

    PubMed

    Poolman, Rudolf W; Verhaar, Jan A N; Schreurs, B Willem; Bom, L Paul A; Nelissen, Rob G H H; Koot, Henk W J; Goosen, Jon H M; Verheyen, Cees C P M

    2015-01-01

    We describe the implementation process of hip prostheses selection in the Netherlands. The recent problems with large head metal-on-metal hip prostheses resulted in substantial damage to the surgeons' credibility and reputation in the media. This led to a true sense of urgency among orthopaedic surgeons to increase their activities to secure patient safety. The board of the Dutch Orthopaedic Association (NOV) in the Netherlands established a Dutch Hip Task Force (DHTF) with the explicit assignment of formulating criteria to classify the quality of total hip implants on the Dutch market based on survivorship. The aim was to offer unequivocal information enabling a balanced choice of total hip prosthesis. The ultimate goal of the NOV is that all implanted total hip prostheses implanted in the Netherlands are based on reliable clinical evidence. The DHTF decided to adapt the principles of the National Institute for Health and Care Excellence (NICE, UK) (www.nice.org.uk). The taskforce uses data from the registries as well as the Orthopaedic Data Evaluation Panel (ODEP). If the ODEP guidelines had been chosen as standard alone, one quarter of our listed hip components would not have been included. In our view this underlines the strength in the Dutch approach where high quality registry data and ODEP ratings are complementary and result in a list of reliable hip prostheses. Most importantly we offer patients insights into the known quality of the implants by sharing the results of our implant review. This will facilitate shared decision making by empowering patients in their knowledge on available hip arthroplasties.

  4. [Damage to implants due to high-frequency electrocautery : analysis of four fractured hip endoprostheses shafts].

    PubMed

    Konrads, C; Wente, M N; Plitz, W; Rudert, M; Hoberg, M

    2014-12-01

    In revision surgery of joints, high-frequency electrocauterization instruments are used for homeostasis and dissection of soft tissue. If there is contact of these instruments with the metal implants, flashover can occur. This can lead to thermal microstructural changes in the material and as a consequence may reduce the fatigue strength of the implant. Four cases of hip revision surgeries were analysed. In all cases flashovers occurred and secondarily, the titanium hip endoprosthesis stem broke in the neck section of the prosthesis. The conducted investigations showed that contact between the high-frequency instrument and the anterolateral aspect of the endoprosthesis neck had occurred. Electrothermal implant damage was found in the broken area. If in hip revision surgery the stem is not to be replaced, contact between high-frequency instruments and the metal implant should be avoided.

  5. Effect of ion implantation on the tribology of metal-on-metal hip prostheses.

    PubMed

    Bowsher, John G; Hussain, Azad; Williams, Paul; Nevelos, Jim; Shelton, Julia C

    2004-12-01

    Nitrogen ion implantation (which considerably hardens the surface of the bearing) may represent one possible method of reducing the wear of metal-on-metal (MOM) hip bearings. Currently there are no ion-implanted MOM bearings used clinically. Therefore a physiological hip simulator test was undertaken using standard test conditions, and the results compared to previous studies using the same methods. N2-ion implantation of high carbon cast Co-Cr-Mo-on-Co-Cr-Mo hip prostheses increased wear by 2-fold during the aggressive running-in phase compared to untreated bearing surfaces, plus showing no wear reductions during steady-state conditions. Although 2 specimens were considered in the current study, it would appear that ion implantation has no clinical benefit for MOM.

  6. Wear testing of a canine hip resurfacing implant using highly cross-linked polyethylene.

    PubMed

    Warburton, Kevin J; Everingham, John B; Helms, Jillian L; Kazanovicz, Andrew J; Hollar, Katherine A; Brourman, Jeff D; Fox, Steven M; Lujan, Trevor J

    2017-09-23

    Hip resurfacing offers advantages for young active patients afflicted with hip osteoarthritis, and may also be a beneficial treatment for adult canines. Conventional hip resurfacing uses metal-on-metal bearings to preserve bone stock, but it may be feasible to use metal-on-polyethylene bearings to reduce metal wear debris, while still preserving bone. This study characterized the short-term wear behavior of a novel hip resurfacing implant for canines that uses a 1.5 mm thick liner of highly cross-linked polyethylene in the acetabular component. This implant was tested in an orbital bearing machine that simulated canine gait for 1.1 million cycles. Wear of the liner was evaluated using gravimetric analysis and by measuring wear depth with an optical scanner. The liners had a steady-state mass wear rate of 0.99 ± 0.17 mg per million cycles, and an average wear depth in the central liner region of 0.028 mm. No liners, shells, or femoral heads had any catastrophic failure due to yielding or fracture. These results suggest that the thin liners will not prematurely crack after implantation in canines. This is the first hip resurfacing device developed for canines, and this study is the first to characterize the in vitro wear of highly cross-linked polyethylene liners in a hip resurfacing implant. The canine implant developed in this study may be an attractive treatment option for canines afflicted with hip osteoarthritis, and can serve as a valuable animal model to support the development of metal-on-polyethylene hip resurfacing technology for human patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. High-tech hip implant for wireless temperature measurements in vivo.

    PubMed

    Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N; Damm, Philipp

    2012-01-01

    When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2-10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants.

  8. High-Tech Hip Implant for Wireless Temperature Measurements In Vivo

    PubMed Central

    Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N.; Damm, Philipp

    2012-01-01

    When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2–10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants. PMID:22927973

  9. Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis

    PubMed Central

    Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo

    2016-01-01

    Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460

  10. Mechanical properties of human bone-implant interface tissue in aseptically loose hip implants.

    PubMed

    Kraaij, Gert; Zadpoor, Amir A; Tuijthof, Gabrielle J M; Dankelman, Jenny; Nelissen, Rob G H H; Valstar, Edward R

    2014-10-01

    The main cause of failure in total hip replacement is aseptic loosening which is associated with the formation of a periprosthetic fibrous (interface) tissue. Despite important applications for finite element modeling of loose implants, the mechanical properties of the bone-implant interface tissue have never been measured in humans. In this study, we performed unconfined compression tests to characterize the mechanical properties of the interface tissue and to determine the parameters of various hyperelastic material models which were fitted to the measurements. Human interface tissues were retrieved during 21 elective revision surgeries from aseptically loosened cemented (N=10) and uncemented hip implants (N=11). Specimens were tested at a fixed deformation rate of 0.1mm/min up to a maximum force of 10N. Elastic moduli for low and high strain regions of the stress-strain curves were determined. Interface tissue from aseptically loose cemented prostheses shows higher elastic moduli (mean=1.85MPa, 95% C.I.=1.76-1.95MPa) in the high strain region as compared to that of the interface tissue from the cementless group (mean=1.65MPa, 95% C.I.=1.43-1.88MPa). The 5-terms Mooney-Rivlin model ( [Formula: see text] ) described the stress-strain behavior the best. Large variations in the mechanical behavior were observed both between specimens from the same patient as between those of different patients. The material model parameters were therefore estimated for the mean data as well as for the curves with the highest and lowest strain at the maximum load. The model parameters found for the mean data were C1=-0.0074MPa, C2=0.0019MPa, C3=0MPa, C4=-0.0032MPa and C5=0MPa in the cemented group and C1=-0.0137MPa, C2=0.0069MPa, C3=0.0026MPa, C4=-0.0094MPa and C5=0MPa in the cementless group. The results of this study can be used in finite element computer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Surface evaluation of orthopedic hip implants marketed in Brazil

    NASA Astrophysics Data System (ADS)

    Souza, M. M.; Trommer, R. M.; Maru, M. M.; Roesler, C. R. M.; Barros, W. S.; Dutra, M. S.

    2016-07-01

    One of the factors that contribute to the quality of total hip prostheses is the degree of accuracy in the manufacturing of the joint surfaces. The dimensional control of joint components is important because of its direct influence on the durability and, consequently, in the patients’ life quality. This work presents studies on the form and roughness of orthopedic hip prostheses marketed in Brazil. The results provide data for quality control of the surfaces of the femoral heads and acetabular components of hip prostheses and indicate the need of improvement in the procedures used to this control.

  12. Investigation of Wear and Corrosion of a High-Carbon Stellite Alloy for Hip Implants

    NASA Astrophysics Data System (ADS)

    Hu, P. S.; Liu, R.; Liu, J.; McRae, G.

    2014-04-01

    Low-carbon Stellite 21 has been used as hip implant material for a number of decades; however, its limited metal-on-metal bearing has resulted in loosening between the femoral head and the acetabular cup of hip implants. In order to improve the metal-on-metal bearing, it is proposed that a high-carbon alloy, Stellite 720, surface coating be applied on Stellite 21 hip implants to improve mechanical and tribological performance. For this coating to be practical, it must also meet the requirements of corrosion resistance for orthopedic implant materials. In this research, Stellite 720 is investigated with pin-on-disk wear tests, and electrochemical and immersion corrosion tests in simulated human body fluid (Hank's solution; pH 7.4 at temperature of 37°C). The experimental results demonstrate that Stellite 720 exhibits much better wear resistance than Stellite 21, and has the potential for better corrosion resistance as well. The applicability of coating Stellite 21 hip implants with Stellite 720 is discussed.

  13. Importance of preclinical evaluation of wear in hip implant designs using simulator machines.

    PubMed

    Trommer, Rafael Mello; Maru, Márcia Marie

    2017-01-01

    Total hip arthroplasty (THA) is a surgical procedure that involves the replacement of the damaged joint of the hip by an artificial device. Despite the recognized clinical success of hip implants, wear of the articulating surfaces remains as one of the critical issues influencing performance. Common material combinations used in hip designs comprise metal-on-polymer (MoP), ceramic-on-polymer (CoP), metal-on-metal (MoM), and ceramic-on-ceramic (CoC). However, when the design of the hip implant is concerned besides the materials used, several parameters can influence its wear performance. In this scenario, where the safety and efficacy for the patient are the main issues, it is fundamental to evaluate and predict the wear rate of the hip implant design before its use in THA. This is one of the issues that should be taken into account in the preclinical evaluation step of the product, in which simulated laboratory tests are necessary. However, it is fundamental that the applied motions and loads can reproduce the wear mechanisms physiologically observed in the patient. To replicate the in vivo angular displacements and loadings, special machines known as joint simulators are employed. This article focuses on the main characteristics related to the wear simulation of hip implants using mechanical simulators, giving information to surgeons, researchers, regulatory bodies, etc., about the importance of preclinical wear evaluation. A critical analysis is performed on the differences in the principles of operation of simulators and their effects on the final results, and about future trends in wear simulation.

  14. Implant materials for hip endoprostheses: old proofs and new trends.

    PubMed

    Semlitsch, M; Willert, H G

    1995-01-01

    To judge the significance of a hip joint replacement, the clinical results over 10-20 years must be evaluated. Today, still over half of all hip endoprostheses involves cement fixation. The rest is uncemented, in direct contact with bone. Total hip prostheses with polyethylene cups are equipped either with cobalt-, iron-, surface-hardened titanium-based metal or Al2O3 ceramic ball heads. The pairing Al2O3/Al2O3 and CoCrMoC metal/metal for cups and balls are extremely wear resistant. Most of the cementless cups have spherical or conical cobalt- or titanium-based metal shells with inserts made of polyethylene or CoCrMoC metal. For the fixation stems, high-strength iron-, cobalt- or titanium-based wrought metals are preferred. A taper spigot connection between metallic or ceramic ball heads and stems allows a modular design of hip joint replacements. We have learnt much from the mistakes of the last 40 years in hip endoprosthetics, and there is no excuse to repeat them again.

  15. Management of metal-on-metal hip implant patients: Who, when and how to revise?

    PubMed Central

    Berber, Reshid; Skinner, John A; Hart, Alister J

    2016-01-01

    The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754

  16. High revision rate at 5 years after hip resurfacing with the Durom implant.

    PubMed

    Naal, Florian D; Pilz, Ronny; Munzinger, Urs; Hersche, Otmar; Leunig, Michael

    2011-09-01

    There is growing evidence that different resurfacing implants are associated with variable survival and revision rates. A registry analysis indicated the Durom resurfacing implant had high revision rates at 5 years, whereas three original studies reported low revision rates at short-term followups. Thus, the revision rates appear controversial. We therefore assessed (1) the survivorship including differences between women and men at a mean of 5 years after resurfacing with the Durom implant, and (2) clinical scores and radiographic parameters. We prospectively followed all 100 Durom hip resurfacings implanted in 91 patients (25 women and 66 men; mean age, 52 years) between 2003 and 2004. Survivorship analysis was performed with pending revision or revision for any reason as the endpoint. The minimum followup was 47 months (mean, 60 months; range, 47-72 months). At a mean of 5 years, 11 hips were revised for various reasons. Cumulative survival was 88.2% for all patients and 81.5% for women. The mean Oxford (OHS) and Harris hip (HHS) scores were 14.6 and 94.7, respectively. The mean UCLA activity level was 7.9. Sclerotic changes around the short femoral stem (pedestal sign) were detected in 40% of the hips. We observed considerable femoral neck thinning with component-to-neck ratios of 0.85 preoperatively and 0.82 at 5 years. Our study highlights a high revision rate 5 years after hip resurfacing with the Durom implant. This observation underlines previous findings from registry data and suggests that revision rates increase with time. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

  17. Implant options for the treatment of intertrochanteric fractures of the hip: rationale, evidence, and recommendations.

    PubMed

    Socci, A R; Casemyr, N E; Leslie, M P; Baumgaertner, M R

    2017-01-01

    The aim of this paper is to review the evidence relating to the anatomy of the proximal femur, the geometry of the fracture and the characteristics of implants and methods of fixation of intertrochanteric fractures of the hip. Relevant papers were identified from appropriate clinical databases and a narrative review was undertaken. Stable, unstable, and subtrochanteric intertrochanteric fractures vary widely in their anatomical and biomechanical characteristics, as do the implants used for their fixation. The optimal choice of implant addresses the stability of the fracture and affects the outcome. The treatment of intertrochanteric fractures of the hip has evolved along with changes in the design of the implants used to fix them, but there remains conflicting evidence to guide the choice of implant. We advocate fixation of 31A1 fractures with a sliding hip screw and all others with an intramedullary device. Cite this article: Bone Joint J 2017;99-B:128-33. ©2017 The British Editorial Society of Bone & Joint Surgery.

  18. Precaution, governance and the failure of medical implants: the ASR((TM)) hip in the UK.

    PubMed

    Wienroth, Matthias; McCormack, Pauline; Joyce, Thomas J

    2014-01-01

    Hip implants have provided life-changing treatment, reducing pain and improving the mobility and independence of patients. Success has encouraged manufacturers to innovate and amend designs, engendering patient hopes in these devices. However, failures of medical implants do occur. The failure rate of the Articular Surface Replacement metal-on-metal hip system, implanted almost 100,000 times world-wide, has re-opened debate about appropriate and timely implant governance. As commercial interests, patient hopes, and devices' governance converge in a socio-technical crisis, we analyse the responses of relevant governance stakeholders in the United Kingdom between 2007 and 2014. We argue that there has been a systemic failure of the governance system entrusted with the safety of patients fitted with medical implants. Commercial considerations of medical implants and the status quo of medical implant governance have been given priority over patient safety despite the availability of significant failure data in an example of uncertainty about what constitutes appropriate precautionary action.

  19. Total Hip Arthroplasty for Implant Rupture after Surgery for Atypical Subtrochanteric Femoral Fracture

    PubMed Central

    Ozaki, Yu; Ochi, Hironori; Watari, Taiji; Matsumoto, Mikio; Kaneko, Kazuo

    2016-01-01

    Treatment methods for delayed union and nonunion of atypical femoral fracture are still controversial. Moreover, no treatment method has been established for implant rupture caused by delayed union and nonunion. We encountered a 74-year-old female in whom nonunion-induced implant rupture occurred after treatment of atypical subtrochanteric femoral fracture with internal fixation using a long femoral nail. It was unlikely that sufficient fixation could be obtained by repeating osteosynthesis alone. Moreover, the patient was elderly and early weight-bearing activity was essential for early recovery of ADL. Based on these reasons, we selected one-stage surgery with total hip arthroplasty and osteosynthesis with inverted condylar locking plate as salvage procedures. Bone union was achieved at 6 months after surgery. This case illustrated that osteosynthesis-combined one-staged total hip arthroplasty could be considered as one of the options for nonunion-induced implant rupture of atypical femoral subtrochanteric fracture. PMID:27818818

  20. Development of optimized epoxy graphite implant for the total hip joint.

    PubMed

    Iyer, L S; Jayasekaran, T; Blunck, C F; Selvam, R P

    1984-01-01

    Various metal implants are available for total hip joint replacements. There are problems associated with the micromovement of the implants with bone and/or with bone cement and about ten percent failure cases are reported. The mechanical properties of the metal implants do not match with that of human bone in the femur resulting in a stress distribution in the femur different from one without implant. Many researchers are working with different materials like alloy materials with lower modulus of elasticity, ceramic, etc. The study conducted at S.D.S.M. & T. biomechanics laboratory investigates the feasibility of using epoxy graphite as an implant material. The mechanical properties of the implant material are being optimized using experimental and analytical methods. The reflection polariscope method (photo stress method) was used to determine the micromovement of the implant and the bone, and stress distribution in the femur subjected to cyclic loading. A finite element method was used to optimize the mechanical properties of the implant to obtain a stress distribution closer to the one without implant. An epoxy graphite implant with optimized mechanical properties is being manufactured and tests are in progress.

  1. [Osteointegration of porous tantalum stems implanted in avascular necrosis of the hip].

    PubMed

    Fernández-Fairen, Mariano; Murcia, Antonio; Iglesias, Roberto; Querales, Virginia; Sevilla, Pablo; Gil, Javier

    2008-01-01

    Efficacy of osteointegration of tantalum porous systems has been demonstrated through animal experimentation. However, there is a lack of studies that evaluate osteointegration of implants retrieved after a period of implantation in humans. For this study, eight rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty three months. Observation during this study has confirmed effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. Bone in growth however, proved to be of a slower and less intense degree than that resulting within animal species during first months after implantation. Nevertheless, the results obtained in the quantitative evaluation of this process proved to be similar to those results achieved by other authors in previous experimental studies.

  2. A biomechanical assessment of modular and monoblock revision hip implants using FE analysis and strain gage measurements

    PubMed Central

    2010-01-01

    Background The bone loss associated with revision surgery or pathology has been the impetus for developing modular revision total hip prostheses. Few studies have assessed these modular implants quantitatively from a mechanical standpoint. Methods Three-dimensional finite element (FE) models were developed to mimic a hip implant alone (Construct A) and a hip implant-femur configuration (Construct B). Bonded contact was assumed for all interfaces to simulate long-term bony ongrowth and stability. The hip implants modeled were a Modular stem having two interlocking parts (Zimmer Modular Revision Hip System, Zimmer, Warsaw, IN, USA) and a Monoblock stem made from a single piece of material (Stryker Restoration HA Hip System, Stryker, Mahwah, NJ, USA). Axial loads of 700 and 2000 N were applied to Construct A and 2000 N to Construct B models. Stiffness, strain, and stress were computed. Mechanical tests using axial loads were used for Construct A to validate the FE model. Strain gages were placed along the medial and lateral side of the hip implants at 8 locations to measure axial strain distribution. Results There was approximately a 3% average difference between FE and experimental strains for Construct A at all locations for the Modular implant and in the proximal region for the Monoblock implant. FE results for Construct B showed that both implants carried the majority (Modular, 76%; Monoblock, 66%) of the 2000 N load relative to the femur. FE analysis and experiments demonstrated that the Modular implant was 3 to 4.5 times mechanically stiffer than the Monoblock due primarily to geometric differences. Conclusions This study provides mechanical characteristics of revision hip implants at sub-clinical axial loads as an initial predictor of potential failure. PMID:20462448

  3. Effect of friction and clearance on kinematics and contact mechanics of dual mobility hip implant.

    PubMed

    Gao, Yongchang; Chai, Wei; Wang, Ling; Wang, Manyi; Jin, Zhongmin

    2016-01-01

    The dual mobility hip implant has been introduced recently and increasingly used in total hip replacement to maintain the stability and reduce the risk of post-surgery dislocation. However, the kinematics and contact mechanisms of dual mobility hip implants have not been investigated in detail in the literature. Therefore, finite element method was adopted in this study to investigate dynamics and contact mechanics of a typical metal-on-polymer dual mobility hip implant under different friction coefficient ratios between the inner and the outer articulations and clearances/interferences between the ultra-high-molecular-weight polyethylene liner and the metal back shell. A critical ratio of friction coefficients between the two pairs of contact interfaces was found to mainly determine the rotating surfaces. Furthermore, an initial clearance between the liner and the back shell facilitated the rotation of the liner while an initial interference prevented such a motion at the outer articulating interface. In addition, the contact area and the sliding distance at the outer articulating surface were markedly greater than those at the inner cup-head interface, potentially leading to extensive wear at the outer surface of the liner. © IMechE 2015.

  4. Lubrication and friction prediction in metal-on-metal hip implants.

    PubMed

    Wang, F C; Brockett, C; Williams, S; Udofia, I; Fisher, J; Jin, Z M

    2008-03-07

    A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

  5. Implant survival and radiographic outcome of total hip replacement in patients less than 20 years old

    PubMed Central

    Tsukanaka, Masako; Halvorsen, Vera; Nordsletten, Lars; EngesæTer, Ingvild Ø; EngesæTer, Lars B; Marie Fenstad, Anne; Röhrl, Stephan M

    2016-01-01

    Background and purpose Total hip replacement (THR) is not recommended for children and very young teenagers because early and repetitive revisions are likely. We investigated the clinical and radiographic outcomes of THR performed in children and teenage patients. Patients and methods We included 111 patients (132 hips) who underwent THR before 20 years of age. They were identified in the Norwegian Arthroplasty Register, together with information on the primary diagnosis, types of implants, and any revisions that required implant change. Radiographs and Harris hip score (HHS) were also evaluated. Results The mean age at primary THR was 17 (11–19) years and the mean follow-up time was 14 (3–26) years. The 10-year survival rate after primary THR (with the endpoint being any revision) was 70%. 39 patients had at least 1 revision and 16 patients had 2 or more revisions. In the latest radiographs, osteolysis and atrophy were observed in 19% and 27% of the acetabulae and 21% and 62% of the femurs, respectively. The mean HHS at the final follow-up was 83 (15–100). Interpretation The clinical score after THR in these young patients was acceptable, but many revisions had been performed. However, young patients with developmental dysplasia of the hip had lower implant survival. Moreover, the bone stock in these patients was poor, which could complicate future revisions. PMID:27435903

  6. Finite element analysis of sliding distance and contact mechanics of hip implant under dynamic walking conditions.

    PubMed

    Gao, Yongchang; Jin, Zhongmin; Wang, Ling; Wang, Manyi

    2015-06-01

    An explicit finite element method was developed to predict the dynamic behavior of the contact mechanics for a hip implant under normal walking conditions. Two key parameters of mesh sensitivity and time steps were examined to balance the accuracy and computational cost. Both the maximum contact pressure and accumulated sliding distance showed good agreement with those in the previous studies using the implicit finite element analysis and analytical methods. Therefore, the explicit finite element method could be used to predict the contact pressure and accumulated sliding distance for an artificial hip joint simultaneously in dynamic manner.

  7. Utility of modular implants in primary total hip arthroplasty.

    PubMed

    Berry, Daniel J

    2014-04-01

    Most surgeons believe that some level of modularity has a valuable role to play in primary total hip arthroplasty. However, all modular junctions carry some risk and recent problems with taper tribocorrosion have elevated concerns. These problems suggest that more rigorous preclinical testing should be undertaken before new types of modularity are widely used. Efforts to further optimize these junctions where they are needed, avoidance of gratuitous use of modular junctions where they provide only modest benefits, and a judicious approach to adopting new modularity are reasonable approaches to current concerns. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Treatment of proximal femur infections with antibiotic-loaded cement spacers

    PubMed Central

    Kelm, J.; Bohrer, P.; Schmitt, E.; Anagnostakos, K.

    2009-01-01

    In case of periprosthetic hip infections the implantation of antibiotic-loaded PMMA spacers is accepted for an adequate treatment option. Although their indication for the treatment of destructive, bacterial infections of the proximal femur would make sense, literature data are scarce. Hence, the aim of this study was to evaluate the efficacy of antibiotic-impregnated spacers in the treatment of proximal femur infections. In 10 consecutive patients (5 M/ 5 F, mean age 66 y.) with bacterial proximal femur infections, a femoral head/neck resection was prospectively performed with a subsequent implantation of an antibiotic-loaded spacer. The joint-specific outcome was evaluated by the Merle d´Aubigne and the Mayo hip score, the general outcome by SF-36. The time periods were divided into “infection situation”, “between stages” and meanly 1 year “after prosthesis implantation”. The spacers were meanly implanted over 90 [155-744] days. In all cases an infection eradication could be achieved. After infection eradication, a prosthesis implantation was performed in 8 cases. The general scores showed significant increases at each time period. With regard to the dimension “pain”, both scores demonstrated a significant increase between “infection situation” and “between stages”, but no significance between “between stages” and “after prosthesis implantation”. Spacers could be indicated in the treatment of proximal femur infections. Besides an infection eradication, a pain reduction is also possible. PMID:19841730

  9. [Modified mini-Hardinge access for hip prosthesis implantation in the supine position].

    PubMed

    Mazoochian, F; Schmidutz, F; Fottner, A; Jansson, V

    2014-04-01

    Total hip arthroplasty with a minimal-incision technique that can be performed in the widely used supine position. The accustomed and good overview of this position allows safe positioning of the implant and combines this with the advantage of a soft tissue preserving technique. All standard instruments and implants can be further applied. Primary and secondary coxarthrosis, femoral head necrosis. Revision surgery, severe anatomic deformity, implantation of hip resurfacing arthroplasty. Supine position. The skin incision runs from the innominate tubercle proximally and falls slightly in the dorsal direction (20-30°). Incision of the iliotibial tract and exposure of the vastogluteal muscle sling. Starting from the greater trochanter, the sinewy onset of the minimal and medium gluteal muscle is split with an arched-shaped incision, which also falls proximally in the dorsal direction. Exposition of the joint capsule, longitudinal incision and resection of the ventrolateral parts. Dislocation of the hip by a combined adduction and external rotation movement. Osteotomy of the femoral neck and resection of the femoral head are performed in a figure-of-four position without adduction. To prepare the acetabulum and to insert the cup, the leg is placed in neutral position with a slight flexion of 20° in the hip. Preparation of the femur and implantation of the stem is again performed in a figure-of-four position in adduction. Reduction of the hip and stepwise wound closure. Mobilization on postoperative day 1. Starting with half weight bearing and after completed wound healing rapid increase to full weight bearing. Intensive physiotherapy and rehabilitation. Thrombosis prophylaxis according to guidelines. The mini-incision approach has successfully been used in our clinic for years. Between September 2004 and November 2005, the less-invasive technique was evaluated in a randomized controlled trial with 51 patients (52 hips). Compared to the standard approach a

  10. Implant-bone interface healing and adaptation in resurfacing hip replacement.

    PubMed

    Dickinson, Alexander; Taylor, Andrew; Browne, Martin

    2012-01-01

    Hip resurfacing demonstrates good survivorship as a treatment for young patients with osteoarthritis, but occasional implant loosening failures occur. On the femoral side there is radiographic evidence suggesting that the implant stem bears load, which is thought to lead to proximal stress shielding and adaptive bone remodelling. Previous attempts aimed at reproducing clinically observed bone adaptations in response to the implant have not recreated the full set of common radiographic changes, so a modified bone adaptation algorithm was developed in an attempt to replicate more closely the effects of the prosthesis on the host bone. The algorithm features combined implant-bone interface healing and continuum bone remodelling. It was observed that remodelling simulations that accounted for progressive gap filling at the implant-bone interface predicted the closest periprosthetic bone density changes to clinical X-rays and DEXA data. This model may contribute to improved understanding of clinical failure mechanisms with traditional hip resurfacing designs and enable more detailed pre-clinical analysis of new designs.

  11. Cost drivers in total hip arthroplasty: effects of procedure volume and implant selling price.

    PubMed

    Kelly, Michael P; Bozic, Kevin J

    2009-01-01

    Total hip arthroplasty (THA), though a highly effective procedure for patients with end-stage hip disease, has become increasingly costly, both because of increasing procedure volume and because of the introduction and widespread use of new technologies. Data regarding procedure volume and procedure costs for THA were obtained from the National Inpatient Sample and other published sources for the years 1995 through 2005. Procedure volume increased 61% over the period studied. When adjusted for inflation, using the medical consumer price index, the average selling price of THA implants increased 24%. The selling price of THA implants as a percentage of total procedure costs increased from 29% to 60% during the period under study. The increasing cost of THA in the United States is a result of both increased procedure volume and increased cost of THA implants. No long-term outcome studies related to use of new implant technologies are available, and short-term results have been similar to those obtained with previous generations of THA implants. This study reinforces the need for a US total joint arthroplasty registry and for careful clinical and economic analyses of new technologies in orthopedics.

  12. [Radiological analysis of osseointegration after implantation of the Zweymüller-Alloclassic total hip system].

    PubMed

    Dohle, J; Becker, W; Braun, M

    2001-01-01

    The purpose of this study was to identify typical radiological patterns of osseointegration following implantation of the Zweymüller-Alloclassic total hip system. The follow-up included the clinical and radiological evaluation of 115 consecutive hips. For each case the screw direction of the cup was calculated individually to fully observe the bony surroundings by properly tilted X-ray beam. After 8.1 years, the Harris hip score was 88.5 points on average. Trabecular condensations leading toward the threads of the cup were observed in 100 cases, underlining the importance of the threads for load transfer. A complete intrusion of the threads into the pelvic bone was not accomplished in 23 cases with marked sclerosis of the acetabulum. The reduced connection, however, did not impair stability or function. The area of the distal stem is characterized by cortical hypertrophy and trabecular condensation of the neighbouring marrow. Linear radiolucencies were frequently observed in Gruen-Zone 1 and 7, in 5 cases extending into zone 2 and 6 without influence on the clinical function of the implant. Material and geometry of the Zweymüller total hip lead to a load transfer through the threads of the cup. The integration of the stem relies on cortical interlocking. Proximal linear radiolucencies do not impair function. The signs of osseointegration around the cup can be fully demonstrated only by a specially tilted X-ray beam at a right angle to the screw direction of the cup.

  13. Optical measurement system for preparation and after-OP-check of a hip joint endoprothetic implantation

    NASA Astrophysics Data System (ADS)

    Maschke, R.; Lempe, B.; Taudt, Ch.; Rudek, F.; Baselt, T.; Basan, F.; Grunert, R.; Hartmann, P.

    2014-02-01

    With 332,000 operations carried out every year, the implantation of an artificial hip joint is one of the most common surgical operations performed in the US. According to prognosis which takes the demographical change into account, the number of these operations will increase in the coming years. One of the essential requirements is the perfect reconstruction of the biomechanical functions, especially the knowledge about the center of the hip rotation and the length of the leg. Based on this information it is possible to ensure the right position of the newly set leg during surgery. The aim of this work is to present and evaluate an optical measurement method in order to gather information about the center of the hip joint and the leg length. An appropriate laboratory setup has been designed and implemented in order to evaluate two different approaches: a structured light-method consisting of a DLP-Beamer or a laser source which projects defined patterns onto the patient and a marker-based system. Together with this both methods are combined with custom software to determine the hip joint center and the leg length with an accuracy of around +/- 0.2 inches. The clinical use of the tested approaches would give the surgeon the opportunity to reset the implant-parameters in the course of the surgery. In this way subsequent illnesses such as scoliotic pelvis can be prevented.

  14. Development of fatigue lifetime predictive test methods for hip implants: part I. Test methodology.

    PubMed

    Styles, C M; Evans, S L; Gregson, P J

    1998-06-01

    The fatigue failure of hip joint prostheses will be expected to assume more importance in second generation implants aimed at younger, more active patients. Furthermore, new designs and material combinations including coatings (e.g. hydroxyapatite) may introduce fatigue problems that as yet have not been considered. The current research makes an initial attempt to develop accelerated fatigue testing procedures to enhance the methodology of hip implant lifetime prediction. Tests conducted on a 'model' four point bendbar testpiece (mill-annealed Ti-6A1-4V) highlighted that the accelerated test must be conducted in a physiological solution such as Ringer's at 37 degrees C. The introduction of superimposed block overloads (50 cycles) to signify stair ascent/descent or fast walking and single overloads to signify sit/stand movements or stumbling were found to reduce fatigue life by > 50%. The findings of this fatigue study were combined with biomechanics studies to construct a variable amplitude 'in-service' load spectrum for testing hip implants. Using ambulatory trial data, a simple load sequence was designed containing 4 single (sit/stand movements) and 3 block (stair ascent/descent) overloads that repeated ten times gave one days activity; single overloads repeated every 110 base cycles (normal walking) and block overloads 80, 110 (morning/evening) and 250 (daytime) base cycles.

  15. [Possibilities of follow-up imaging after implantation of a carbon fiber-reinforced hip prosthesis].

    PubMed

    Krüger, T; Alter, C; Reichel, H; Birke, A; Hein, W; Spielmann, R P

    1998-03-01

    There are many problems in the radiological diagnosis of aseptic loosening in total hip arthroplasty. Computed tomography (CT) and magnetic resonance tomography (MRT) are not usable for metallic implants (stainless steel, cobalt alloy, titanium alloy). From April 1993 to December 1993 15 CFRP non-cemented hip prostheses have been implanted. In a prospective clinical study plane radiographs, CT and MRT have been analysed. Three stems were revised (1 femoral fracture, 1 severe thigh pain, 1 aseptic loosening). CFRP are not visible in plane radiographs. There was a complete (two-third of the cases) or nearly complete (one-third of the cases) small sclerotic interface between the prosthesis and the bone, these were apparent in CT and MRT in stable implant cases and did not have any clinical correlations. The small sclerotic interface is quite different in comparison to so called "Reactive Lines". In one case of aseptic loosening there was an interposition of soft tissue between prosthesis and bone in MRT and CT. CFRP inaugurates new diagnostic possibilities in aseptic loosening of hip prosthesis and in tumour surgery too.

  16. Early failure of total hip replacements implanted at distant hospitals to reduce waiting lists.

    PubMed Central

    Ciampolini, Jac; Hubble, Matthew J. W.

    2005-01-01

    AIM: In the years 1990-1993, in an effort to reduce waiting-list time, a small number of patients were sent from Exeter to hospitals in London to undergo elective total hip replacement. No medium- or long-term follow-up was arranged. Our aim was to audit the outcome of these hip replacements. PATIENTS AND METHODS: Review of the records of the referring medical practices, Regional Health Authority, local orthopaedic hospital and the distant centres at which the surgery was performed identified 31 cases. A total of 27 hip replacements in 24 patients were available for clinical and radiological review. RESULTS: 12 (44%) hips have so far required revision surgery, at a mean of 6.5 years. Of these, three (11%) have been for deep infection. A further three hips (11%) are radiologically loose and are being closely monitored. Two patients (7%) suffered permanent sciatic nerve palsy. CONCLUSIONS: Patients whose surgery was performed locally over a similar time period have a published failure rate of only 4.9%. This difference is highly statistically significant (P < 0.001). The causes for such a difference in outcome were analysed and include surgical technique, implant selection and absence of follow-up. In the light of this evidence, we would like to urge the government to address waiting list problems by investing in the local infrastructure. Expanding those facilities where properly audited and fully accountable surgeons operate must be the way forward. PMID:15720905

  17. Modes of implant failure after hip resurfacing: morphological and wear analysis of 267 retrieval specimens.

    PubMed

    Morlock, Michael M; Bishop, Nick; Zustin, Jozef; Hahn, Michael; Rüther, Wolfgang; Amling, Michael

    2008-08-01

    Resurfacing of the hip joint is experiencing a revival due to improvements in materials, design, and manufacturing techniques. Despite good midterm outcomes, the high early rate of failure and concerns about metal debris require a detailed morphological and wear analysis of retrieved resurfacing implants in order to understand failure mechanisms. A worldwide collection of hip resurfacing revision devices was initiated, and 267 components were received. Devices were analyzed by patient demographics, radiographic positioning, and wear, as well as morphologically and histologically. Specimens were grouped into four different failure types. They were also stratified into rim-loaded or non-rim-loaded groups. Failures were also assessed by surgeon learning-curve effects. Time to failure was significantly different between the four revision-type groups: Specimens with fractures involving the implant rim were most common (46%) and failed earliest after surgery (mean of ninety-nine days), followed by fractures inside the femoral head (20%, 262 days) and loose cups (9%, 423 days). Revisions not due to fractures or cup loosening (25%) occurred at a mean of 722 days after surgery. Rim-loaded implants exhibited an average twenty-one to twenty-sevenfold higher wear rate than implants without rim-loading. Rim-loaded implants also showed a steeper mean cup inclination than their non-rim-loaded counterparts (59 degrees compared with 50 degrees ). Most failures occurred during the learning curve of the surgeon (the first fifty to 100 implantations). Failures on the femoral side usually occur within the first nine months after surgery and appear to be most directly related to the implantation technique or patient selection. Later failures are observed mainly due to acetabular problems, either due to dramatically increased wear or poor cup anchorage. Improper cup anteversion may be similar to or more important than cup inclination in producing excessive wear.

  18. [Reasons for failure of hip resurfacing implants. A failure analysis based on 250 revision specimens].

    PubMed

    Morlock, M M; Bishop, N; Stahmer, F; Zustin, J; Sauter, G; Hahn, M; Krause, M; Rüther, W; Amling, M

    2008-07-01

    Hip resurfacing has been experiencing a revival over the last 5-10 years. Early failure rates are higher than for conventional primary hip arthroplasty. Fractures of the femoral neck or head, cup loosening and persistent pain are the most frequently observed reasons for early revision. In this international retrospective uncontrolled study, 256 revision specimens (219 resurfacing heads, 37 cups) were analysed radiologically, tribologically, morphologically and histologically in order to investigate the failure mechanism. Of the head revisions, 70% were due to neck (median: 67 days after implantation) and head fractures (161 days), 9% were due to cup loosening (350 days) and 21% due to other reasons (602 days). Implants with rim loading (22% of all retrievals, cup inclination 58.0+/-10.9 degrees ) exhibited a head wear rate of 7.1+/-5.2 mm3/year. Non-rim loaded implants exhibited a head wear rate of 0.24+/-0.53 mm3/year (cup inclination 49.0+/-4.0 degrees ). The failure rate was highest during the first 16 weeks after surgery and for the first ten operations performed by a surgeon. Revisions based on problems on the femoral side such as notching and high implantation forces occurred earlier than revisions based on problems on the acetabular side such as cup loosening and high wear due to suboptimal cup position.

  19. Life expectancy of modular Ti6Al4V hip implants: influence of stress and environment.

    PubMed

    Chandra, A; Ryu, J J; Karra, P; Shrotriya, P; Tvergaard, V; Gaisser, M; Weik, T

    2011-11-01

    Stress dependent electrochemical dissolution is identified as one of the key mechanisms governing surface degradation in fretting and crevice corrosion of biomedical implants. The present study focuses on delineating the roles of mechanical stress and chemical conditions on the life expectancy of modular hip implants. First, material removal on a stressed surface of Ti6Al4V subjected to single asperity contact is investigated experimentally to identify the influence of contact load, in-plane stress and chemical environment on mean wear rates. A range of known stress levels are applied to the specimen while its surface is mechanically stimulated in different non-reactive to oxidizing aqueous environments. Evolution of surface degradation is monitored, and its mechanism is elucidated. This phase allows estimation of Preston Constant which is later used in the analysis. Second phase of the work is semi-analytical and computational, where, based on the estimated Preston constant and other material and process parameters, the scratch propensity (consisting of magnitude of scratch depth and their frequency per unit area) due to micro-motion in modular hip implants is estimated. The third phase views these scratches as initial notches and utilizes a mixed-mode fatigue crack propagation model to estimate the critical crack length for onset of instability. The number of loading cycles needed to reach this critical crack length is then labeled as the expected life of the implant under given mechanical and chemical conditions. Implications of different material and process conditions to life expectancy of orthopedic implants are discussed. It is observed that transverse micro-motion, compared to longitudinal micro-motion, plays a far more critical role in determining the implant life. Patient body weight, as well as proximity of the joint fluid to its iso-electric point play key roles in determining wear rates and associated life expectancies of modular hip implants

  20. 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.

  1. Revision total hip and knee arthroplasty implant identification: implications for use of Unique Device Identification 2012 AAHKS member survey results.

    PubMed

    Wilson, Natalia A; Jehn, Megan; York, Sally; Davis, Charles M

    2014-02-01

    FDA's Unique Device Identification (UDI) Rule will mandate manufacturers to assign unique identifiers to their marketed devices. UDI use is expected to improve implant documentation and identification. A 2012 American Association of Hip and Knee Surgeons membership survey explored revision total hip and knee arthroplasty implant identification processes. 87% of surgeons reported regularly using at least 3 methods to identify failed implants pre-operatively. Median surgeon identification time was 20 min; median staff time was 30 min. 10% of implants could not be identified pre-operatively. 2% could not be identified intra-operatively. UDI in TJA registry and UDI in EMR were indicated practices to best support implant identification and save time. FDA's UDI rule sets the foundation for UDI use in patient care settings as standard practice for implant documentation.

  2. Simulation of the mechanical behavior of a HIP implant. Implant fixed to bone by cementation under arbitrary load

    NASA Astrophysics Data System (ADS)

    Oldani, C. R.; Dominguez, A. A.

    2007-11-01

    In a previous work a finite elements model was constructed to simulate a fatigue assay according to the norm IRAM 9422-3. Three materials were studied, two of them are the most used in this type of implant (Stainless steel 3161 and alloy T16A14V) and the third was a new developed titanium alloy (Ti35Nb7Zr5Ta). Static loads were applied to the model according to the highest requirements of the norm and the stress - strain distribution were determined. In this study a simplified analysis of the material's fatigue was done according to the previous work. The best behavior of the titanium alloys vs. the stainless steel was evident. With the objective of studying the behavior of both: the implant and the femur bone, new finite elements models were realized, in which the presence of the bone was considered. Inside the bone, the femoral component of the implant was placed in a similar way of a cemented prosthesis in a total hip arthroplasty. The advantage of the titanium implant related to the stainless steel one, was very clear.

  3. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures.

    PubMed

    Parker, M J; Handoll, H H

    2000-01-01

    Cephalocondylic intramedullary nails which are inserted proximally to distally (cephalocondylic) have been used for the surgical treatment of extracapsular hip fractures. To update and expand our review comparing the Gamma nail with the sliding hip screw (SHS) by comparing all cephalocondylic intramedullary nails with extramedullary implants for the surgical treatment of extracapsular hip fractures in adults. We searched the Cochrane Musculoskeletal Injuries Group trials register, Medline, select orthopaedic journals and conference proceedings, and reference lists of relevant articles. We contacted trialists, colleagues and implant manufacturers. Date of the most recent search: June 1998. All randomised and quasi-randomised trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures. Both reviewers independently assessed trial quality and extracted data. Additional information was sought from all trialists. Wherever appropriate and possible, results were pooled. The one trial of 230 patients comparing the Kuntscher-Y nail with the SHS, reported no major difference the outcome aside from a significantly increased number of patients with leg shortening, and a tendency for poorer recovery of mobility in the Kuntscher-Y nail group. Fourteen trials comparing the Gamma nail with the SHS were included, with data available for 1977 patients. The Gamma nail was associated with an increased risk of operative and later fracture of the femur and an increased re-operation rate. There were no major differences in the incidence of wound infection, mortality or medical complications between implants. Data were inadequate to determine if there were differences for other outcomes. Two trials involving 231 patients compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group: all cases of operative and later fracture of the femur and haematoma occurred in this group. Results for

  4. Implant retention after acute and hematogenous periprosthetic hip and knee infections: Whom, when and how?

    PubMed Central

    Triantafyllopoulos, Georgios K; Soranoglou, Vasileios; Memtsoudis, Stavros G; Poultsides, Lazaros A

    2016-01-01

    Periprosthetic joint infections (PJI) of the hip and the knee are grossly classified as early post-operative, acute hematogenous and late chronic infections. Whereas two-stage exchange arthroplasty is the standard of care in North America for treating chronic infections, irrigation and debridement (I and D) with retention of implants has been used in an attempt to treat the other two types of PJIs. The rationale of this approach is that a PJI may be eradicated without the need of explanting the prostheses, as long as it has not transitioned into a chronic state. With the present paper, we review current evidence regarding the role of I and D with implant retention for treating PJIs of the hip and the knee. While a very wide range of success rates is reported in different studies, a short period of time between initiation of symptoms and intervention seems to play a prominent role with regards to a successful outcome. Moreover, pathogens of higher virulence and resistance to antibiotics are associated with a poorer result. Specific comorbidities have been also correlated with a less favorable outcome. Finally, one should proceed with serial I and Ds only under the condition that a predefined, aggressive protocol is applied. In conclusion, when treating a PJI of the hip or the knee, all the above factors should be considered in order to decide whether the patient is likely to benefit from this approach. PMID:27672567

  5. Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales

    PubMed Central

    Jameson, Simon S.; Mason, James; Baker, Paul N.; Gregg, Paul J.; Deehan, David J.; Reed, Mike R.

    2015-01-01

    Background Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis. Methods and Findings Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data. Results EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long

  6. Mesh morphing for finite element analysis of implant positioning in cementless total hip replacements.

    PubMed

    Bah, Mamadou T; Nair, Prasanth B; Browne, Martin

    2009-12-01

    Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 degrees between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements.

  7. Effects of stemmed and nonstemmed hip replacement on stress distribution of proximal femur and implant.

    PubMed

    Chen, Chun-Ming; Tsai, Wen-Chi; Lin, Shang-Chih; Tseng, Ching-Shiow

    2014-09-26

    Despite improvements in shape, material, and coating for hip stem, both stress shielding and aseptic loosening have been the major drawbacks of stemmed hip arthroplasty. Some nonstemmed systems were developed to avoid rasping off the intramedullary canal and evacuating the bone marrow due to stem insertion. In this study, the finite-element models of one intact, one stemmed, and two nonstemmed femora with minimal removal of the healthy neck were investigated to evaluate their biomechanical effects. The resurfacing (ball-shaped) and fitting (neck-shaped) systems were respectively selected as the representative of the ready- and custom-made nonstemmed implants. The stress distribution and interface micromotion were selected as the comparison indices. The results showed that stress distributions of the two nonstemmed femora are consistently more similar to the intact femur than the stemmed one. Around the proximal femur, the stem definitely induces the stress-shielding phenomenon of its counterparts. The fitting system with the anatomy-shaped cup can make intimate contact with the neck cortex and reduce the bone-cup micromotion and the implant stress. Comparatively, the reamed femoral head provides weaker support to the resurfacing cup causing higher interfacial micromotion. The reserved femoral neck could act as the load-transferring medium from the acetabular cup, femoral neck, to the diaphysial bone, thus depressing the stress-shielding effect below the neck region. If the hip-cup construct can be definitely stabilized, the nonstemmed design could be an alternative of hip arthroplasty for the younger or the specific patients with the disease limited only to the femoral head.

  8. Distinct Immunohistomorphologic Changes in Periprosthetic Hip Tissues from Historical and Highly-crosslinked UHMWPE Implant Retrievals

    PubMed Central

    Baxter, Ryan M; Ianuzzi, Allyson; Freeman, Theresa A; Kurtz, Steven M; Steinbeck, Marla J

    2010-01-01

    Assessment of immune response to implant wear debris in periprosthetic tissue following total hip arthroplasty suggests that multiple factors are involved in the loss implant function. The current study investigated wear debris and the associated immunohistomorphologic changes in tissues from nine patients with historical (gamma air-sterilized) and nine highly-crosslinked UHMWPE implant components. Paraffin embedded tissue sections were evaluated for the presence of histiocytes, giant cells, fibrocartilage/bone and necrosis. To determine the incidence, degree and co-localization of immunohistomorphologic changes and wear, overlapping full-field tissue arrays were collected in brightfield and polarized light. The historical cohort tissues predominantly showed histiocytes associated with significant accumulations of small wear (0.5–2 μm), and giant cells associated with large wear (≥2 μm). Frequently, focal regions of necrosis were observed in association with wear debris. For the highly-crosslinked cohort, inflammation and associated wear debris were limited, but in tissues from patients revised after implantation times of >2 years a response was observed. Whereas significant amounts of fibrocartilage/bone were observed in patients at earlier implantation times. In both cohorts, tissue responses were more extensive in the retroacetabular or proximal femoral regions. The current findings suggest that wear debris-induced inflammation may be a major contributor to the loss of implant function for both the historical and highly-crosslinked cohorts, but it is not the primary cause of early implant loosening. This study highlights the importance of using a more quantitative and standardized assessment of immunohistomorphologic responses in periprosthetic tissues, and emphasizes differences in specific anatomical regions of individual patient tissues. PMID:20740602

  9. The Thrust Plate Hip Prosthesis: A Follow-Up of 15-20 Years With 102 Implants.

    PubMed

    Kaegi, Maja; Buergi, Martin L; Jacob, Hilaire A C; Bereiter, Heinz H

    2016-05-01

    Between November 1992 and January 1999, a cohort of 102 thrust plate hip prostheses was implanted. We now clinically and radiologically evaluate the remaining 73 prostheses with a mean follow-up of 17.2 years. The Harris Hip Score increased from 51.4 points preoperatively to 94.3 points at the time of this follow-up. No further changes in the radiologic findings occurred since the first follow-up, published in 2005, conducted 2-8 years after implantation. Within 15 to 20 years after primary implantation of the 102 prostheses, 6 aseptic loosenings occurred, which correspond to a cumulated survival rate of 94.7% at 17 and 91.8% at 18 years. Although the thrust plate hip prostheses is no longer marketed, the biomechanical behaviour of this unique, clinically successful prosthesis deserves attention. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. The dynamic locking blade plate, a new implant for intracapsular hip fractures: biomechanical comparison with the sliding hip screw and Twin Hook.

    PubMed

    Roerdink, W H; Aalsma, A M M; Nijenbanning, G; van Walsum, A D P

    2009-03-01

    Internal fixation of intracapsular hip fractures results in a high failure rate with non-union and avascular necrosis being the two most important complications. In order to prevent these possible complications treatment should consist of an anatomical reduction and stable fixation by insertion of a low volume, dynamic implant, providing angular and rotational stability to the femoral head. According to these principles a new implant, the dynamic locking blade plate (DLBP) was designed for the fixation of intracapsular hip fractures. We performed a biomechanical analysis in synthetic bone to compare the rotational stability and cut out resistance of the DLBP with a conventional sliding hip screw (SHS) and the more recently developed Twin Hook. The rotational stability of the DLBP proved to be three times higher than the rotational stability of a SHS and two times higher than the Twin Hook. There was no major difference in cut out resistance between the different implants. The design of the DLBP and possible advantages with regard to the healing of an intracapsular hip fracture are discussed.

  11. Electrolytic A12O3 coating on co-cr-mo implant alloys of hip prosthesis.

    PubMed

    Yen, S K; Hsu, S W

    2001-03-05

    The ceramic films over metallic implant surfaces have the potential to improve implant performance with respect to implant fixation, wear, or corrosion. In this study, the electrolytic Al2O3 coatings on F-1537 Co-Cr-Mo alloy were conducted in an aqueous solution of Al(NO3)3. Through the cycle polarization test in Hank's solution, it was found that the corrosion potential and protection potential of the alumina-coated were higher than that of the uncoated, and the corrosion current density was lower. The phase transformation of A12O3 film on Co-Cr-Mo alloy annealed at 800 K revealed todlite (5Al2O3 . H2O) and thetaAl2O3 (113) preferred orientation for 20 min, and thetaAl2O3 (200) preferred orientation with eta phase for 80 min. Scanning electron microscopy/energy dispersive spectroscopy observations after the scratch tests showed that the adhesion of the alumina films on Co-Cr-Mo alloy can load a stress over the yield strength (450 MPa) of Co-Cr-Mo alloy. The wear loss of ultra-high molecular-weight polyethylene to the Al2O3-coated specimen was eight times less than that to the uncoated. It is concluded that such Al2O3-coated films on Co-Cr-Mo implant alloy exhibit excellent quality in corrosion, adhesion, and wear for the application of hip prosthesis.

  12. Nuclear microbeam analysis of wear particles in tissue surrounding failed hip joint implants

    NASA Astrophysics Data System (ADS)

    Grime, G. W.; Triffitt, J. T.; Williamson, M. C.; Athanasou, N. A.

    1994-05-01

    Particulate wear debris from hip joint replacements is an important factor in determining the response of the surrounding tissue to the implants. Failed replacement joints are surrounded by a layer of fibrous tissue showing an inflammatory response to the wear debris. This reaction leads to bone resorption and the eventual failure of the prosthesis. In preliminary experiments the Oxford scanning proton microprobe has been used to study the composition of wear particles in the membranes surrounding failed implants constructed from Ti/V/Al alloy. The membranes were observed to contain 1-10 μm particles with major constituents from the alloy and also from the cement and polyethylene used in the fitting and construction of the implant. Histological staining shows that these particles are associated with areas of high macrophage activity. Individual PIXE analysis of the metal particles indicates that two populations (high Ti/low Al and low Ti/high Al) may be present. These observations will provide further information on the mechanisms of implant degradation.

  13. Static coefficient of friction between stainless steel and PMMA used in cemented hip and knee implants.

    PubMed

    Nuño, N; Groppetti, R; Senin, N

    2006-11-01

    Design of cemented hip and knee implants, oriented to improve the longevity of artificial joints, is largely based on numerical models. The static coefficient of friction between the implant and the bone cement is necessary to characterize the interface conditions in these models and must be accurately provided. The measurement of this coefficient using a repeatable and reproducible methodology for materials used in total hip arthroplasty is missing from the literature. A micro-topographic surface analysis characterized the surfaces of the specimens used in the experiments. The coefficient of friction between stainless steel and bone cement in dry and wet conditions using bovine serum was determined using a prototype computerized sliding friction tester. The effects of surface roughness (polished versus matt) and of contact pressure on the coefficient of friction have also been investigated. The serum influences little the coefficient of friction for the matt steel surface, where the mechanical interactions due to higher roughness are still the most relevant factor. However, for polished steel surfaces, the restraining effect of proteins plays a very relevant role in increasing the coefficient of friction. When the coefficient of friction is used in finite element analysis, it is used for the debonded stem-cement situation. It can thus be assumed that serum will propagate between the stem and the cement mantle. The authors believe that the use of a static coefficient of friction of 0.3-0.4, measured in the present study, is appropriate in finite element models.

  14. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures.

    PubMed

    Parker, M J; Handoll, H H

    2002-01-01

    Cephalocondylic intramedullary nails which are inserted proximally to distally (cephalocondylic) have been used for the surgical treatment of extracapsular hip fractures. To compare all cephalocondylic intramedullary nails with extramedullary implants for the surgical treatment of extracapsular hip fractures in adults. This is the third substantive update of our original review which compared the Gamma nail with the sliding hip screw (SHS). We searched the Cochrane Musculoskeletal Injuries Group trials register, MEDLINE, select orthopaedic journals and conference proceedings, and reference lists of relevant articles. We contacted trialists, colleagues and implant manufacturers. Date of the most recent search: August 2002. All randomised and quasi-randomised trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures. Both reviewers independently assessed trial quality and extracted data. Additional information was sought from all trialists. Wherever appropriate and possible, results were pooled. Seventeen trials comparing the Gamma nail with the SHS were included, with data available for 2472 patients. The Gamma nail was associated with an increased risk of operative and later fracture of the femur and an increased re-operation rate. There were no major differences in the incidence of wound infection, mortality or medical complications between implants. Data were inadequate for other outcomes. Five trials involving 623 patients compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group: all cases of operative and later fracture of the femur occurred in this group. Results for post-operative complications, mortality and functional outcomes were similar in the two groups. One study of 206 patients with a trochanteric fracture showed no advantages for proximal femoral nail (PFN) compared with the SHS. One trial of 60 patients reported favourable preliminary

  15. Total hip arthroplasty following failure of core decompression and tantalum rod implantation.

    PubMed

    Olsen, M; Lewis, P M; Morrison, Z; McKee, M D; Waddell, J P; Schemitsch, E H

    2016-09-01

    One method of femoral head preservation following avascular necrosis (AVN) is core decompression and insertion of a tantalum rod. However, there may be a high failure rate associated with this procedure. The purpose of this study was to document the clinical and radiological outcomes following total hip arthroplasty (THA) subsequent to failed tantalum rod insertion. A total of 37 failed tantalum rods requiring total hip arthroplasty were identified from a prospective database. There were 21 hips in 21 patients (12 men and nine women, mean age 37 years, 18 to 53) meeting minimum two year clinical and radiographic follow-up whose THAs were carried out between November 2002 and April 2013 (mean time between tantalum rod implantation and conversion to a THA was 26 months, 6 to 72). These were matched by age and gender to individuals (12 men, nine women, mean age 40 years, 18 to 58) receiving THA for AVN without prior tantalum rod insertion. There were no functional outcome differences between the two groups. Tantalum residue was identified on all post-operative radiographs in the tantalum group. Linear wear rates were comparable between groups with no evidence of catastrophic wear in either group. In the short term, tantalum rod implantation does not demonstrate an adverse effect on subsequent total joint replacement surgery. There is however, a high rate of retained tantalum debris on post-operative radiographs and thus there is an unknown risk of accelerated articular wear necessitating longer term study. Cite this article: Bone Joint J 2016;98-B:1175-9. ©2016 The British Editorial Society of Bone & Joint Surgery.

  16. In vivo measured joint friction in hip implants during walking after a short rest.

    PubMed

    Damm, Philipp; Bender, Alwina; Duda, Georg; Bergmann, Georg

    2017-01-01

    It has been suspected that friction in hip implants is higher when walking is initiated after a resting period than during continuous movement. It cannot be excluded that such increased initial moments endanger the cup fixation in the acetabulum, overstress the taper connections in the implant or increase wear. To assess these risks, the contact forces, friction moments and friction coefficients in the joint were measured in vivo in ten subjects. Instrumented hip joint implants with telemetric data transmission were used to access the contact loads between the cup and head during the first steps of walking after a short rest. The analysis demonstrated that the contact force is not increased during the first step. The friction moment in the joint, however, is much higher during the first step than during continuous walking. The moment increases throughout the gait cycle were 32% to 143% on average and up to 621% individually. The high initial moments will probably not increase wear by much in the joint. However, comparisons with literature data on the fixation resistance of the cup against moments made clear that the stability can be endangered. This risk is highest during the first postoperative months for cementless cups with insufficient under-reaming. The high moments after a break can also put taper connections between the head and neck and neck and shaft at a higher risk. During continuous walking, the friction moments individually were extremely varied by factors of 4 to 10. Much of this difference is presumably caused by the varying lubrication properties of the synovia. These large moment variations can possibly lead to friction-induced temperature increases during walking, which are higher than the 43.1°C which have previously been observed in a group of only five subjects.

  17. Hip-inspired implant for revision of failed reverse shoulder arthroplasty with severe glenoid bone loss

    PubMed Central

    2014-01-01

    Background and purpose Glenoid reconstruction and inverted glenoid re-implantation is strongly advocated in revisions of failed reverse shoulder arthroplasty (RSA). Nevertheless, severe glenoid deficiency may preclude glenoid reconstruction and may dictate less favorable solutions, such as conversion to hemiarthropasty or resection arthropasty. The CAD/CAM shoulder (Stanmore Implants, Elstree, UK), a hip arthroplasty-inspired implant, may facilitate glenoid component fixation in these challenging revisions where glenoid reconstruction is not feasible. We questioned (1) whether revision arthroplasty with the CAD/CAM shoulder would alleviate pain and improve shoulder function in patients with failed RSA, not amenable to glenoid reconstruction, (2) whether the CAD/CAM hip-inspired glenoid shell would enable secure and durable glenoid component fixation in these challenging revisions. Patients and methods 11 patients with failed RSAs and unreconstructable glenoids underwent revision with the CAD/CAM shoulder and were followed-up for mean 35 (28–42) months. Clinical outcomes included the Oxford shoulder score, subjective shoulder value, pain rating, physical examination, and shoulder radiographs. Results The average Oxford shoulder score and subjective shoulder value improved statistically significantly after the revision from 50 to 33 points and from 17% to 48% respectively. Pain rating at rest and during activity improved significantly from 5.3 to 2.3 and from 8.1 to 3.8 respectively. Active forward flexion increased from 25 to 54 degrees and external rotation increased from 9 to 21 degrees. 4 patients required reoperation for postoperative complications. No cases of glenoid loosening occurred. Interpretation The CAD/CAM shoulder offers an alternative solution for the treatment of failed RSA that is not amenable to glenoid reconstruction. PMID:24650026

  18. In vivo measured joint friction in hip implants during walking after a short rest

    PubMed Central

    Damm, Philipp; Bender, Alwina; Duda, Georg; Bergmann, Georg

    2017-01-01

    Introduction It has been suspected that friction in hip implants is higher when walking is initiated after a resting period than during continuous movement. It cannot be excluded that such increased initial moments endanger the cup fixation in the acetabulum, overstress the taper connections in the implant or increase wear. To assess these risks, the contact forces, friction moments and friction coefficients in the joint were measured in vivo in ten subjects. Instrumented hip joint implants with telemetric data transmission were used to access the contact loads between the cup and head during the first steps of walking after a short rest. Results The analysis demonstrated that the contact force is not increased during the first step. The friction moment in the joint, however, is much higher during the first step than during continuous walking. The moment increases throughout the gait cycle were 32% to 143% on average and up to 621% individually. The high initial moments will probably not increase wear by much in the joint. However, comparisons with literature data on the fixation resistance of the cup against moments made clear that the stability can be endangered. This risk is highest during the first postoperative months for cementless cups with insufficient under-reaming. The high moments after a break can also put taper connections between the head and neck and neck and shaft at a higher risk. Discussion During continuous walking, the friction moments individually were extremely varied by factors of 4 to 10. Much of this difference is presumably caused by the varying lubrication properties of the synovia. These large moment variations can possibly lead to friction-induced temperature increases during walking, which are higher than the 43.1°C which have previously been observed in a group of only five subjects. PMID:28350858

  19. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures.

    PubMed

    Parker, M J; Handoll, H H

    2002-01-01

    Cephalocondylic intramedullary nails which are inserted proximally to distally (cephalocondylic) have been used for the surgical treatment of extracapsular hip fractures. To compare all cephalocondylic intramedullary nails with extramedullary implants for the surgical treatment of extracapsular hip fractures in adults. This is the third update of our original review which compared the Gamma nail with the sliding hip screw (SHS). We searched the Cochrane Musculoskeletal Injuries Group trials register, MEDLINE, select orthopaedic journals and conference proceedings, and reference lists of relevant articles. We contacted trialists, colleagues and implant manufacturers. Date of the most recent search: August 2001. All randomised and quasi-randomised trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures. Both reviewers independently assessed trial quality and extracted data. Additional information was sought from all trialists. Wherever appropriate and possible, results were pooled. The one trial of 230 patients comparing the Kuntscher-Y nail with the SHS, reported no major difference the outcome aside from a significantly increased number of patients with leg shortening, and a tendency for poorer recovery of mobility in the Kuntscher-Y nail group. Seventeen trials comparing the Gamma nail with the SHS were included, with data available for 2472 patients. The Gamma nail was associated with an increased risk of operative and later fracture of the femur and an increased re-operation rate. There were no major differences in the incidence of wound infection, mortality or medical complications between implants. Data were inadequate to determine if there were differences for other outcomes. Five trials involving 603 patients compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group: all cases of operative and later fracture of the femur occurred in this group

  20. In vitro macrophage response to nanometer-size particles from materials used in hip implants

    NASA Astrophysics Data System (ADS)

    VanOs, Robilyn

    Wear particle-induced inflammation leading to periprosthetic osteolysis remains a major cause of hip implant failure. As polyethylene particles from conventional metal-on-polyethylene implants have been associated with these failures, an interest in lower wear metal-on-metal (MM) bearings has emerged. However, the biological effects of nanometer-size chromium oxide particles, predominant type of wear particles produced by MM implants, remain mostly unknown. Therefore, this study aimed to determine the cytotoxicity of nanometer-size Cr2O3 particles on macrophages in vitro, by analyzing their effects on cell mortality and cytokine release and comparing them with those of similarly-sized alumina (Al2O3) particles (known to be relatively bioinert). Results showed that at high concentrations, nanometer-size Cr2O3 particles can be cytotoxic to macrophages, inducing significant decreases in total cell numbers and increases in necrosis. Results also showed that, at high concentrations, the cytotoxicity of Cr 2O3 particles was overall higher than that of Al2O 3 particles, even though Cr2O3 and Al2O 3 are both stable forms of ceramic materials. However, it appeared to be lower than that of previously reported conventional polyethylene and CoCrMo particles. Therefore, chromium oxide particles may not be the main culprit in initiating the inflammatory reaction in MM periprosthetic tissues.

  1. Extramedullary fixation implants and external fixators for extracapsular hip fractures in adults.

    PubMed

    Parker, Martyn J; Das, Avishek

    2013-02-28

    Extramedullary fixation of hip fractures involves the application of a plate and screws to the lateral side of the proximal femur. In external fixators, the stabilising component is held outside the thigh by pins or screws driven into the bone. This is an update of a Cochrane review first published in 1998, and last updated in 2005. To assess the relative effects of different types of extramedullary fixation implant, as well as external fixators, for treating extracapsular proximal femoral (hip) fractures in adults. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (July 2011), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2011, Issue 2), MEDLINE (1966 to June Week 4 2011), EMBASE (1988 to 2011 Week 25), various other databases, conference proceedings and reference lists. Randomised or quasi-randomised controlled trials comparing extramedullary implants or external fixators for fixing extracapsular hip fracture in adults were included. Two review authors independently selected trials, assessed risk of bias and extracted data. Data were pooled where appropriate. The 18 included trials tested seven comparisons in a total of 2615 mainly female and older participants with a total of 2619 fractures. All trials had methodological flaws that may affect the validity of their results.Three trials of 355 participants comparing a fixed nail plate (Jewett or McLaughlin) with the sliding hip screw (SHS) found an increased risk of fixation failure for fixed nail plates.The two trials of 433 participants comparing the Resistance Augmented Bateaux (RAB) plate with the SHS had contrasting results, notably in terms of operative complications, fixation failure and anatomical restoration.One trial of 100 participants comparing the Pugh nail and the SHS found no significant difference between implants.Three trials of 458 participants compared the Medoff plate with the SHS. There was a trend to higher blood losses and

  2. Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement

    PubMed Central

    Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy

    2014-01-01

    Background: The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). Methods: A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. Results: A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head

  3. Comparison and Combination of Dual-Energy- and Iterative-Based Metal Artefact Reduction on Hip Prosthesis and Dental Implants.

    PubMed

    Bongers, Malte N; Schabel, Christoph; Thomas, Christoph; Raupach, Rainer; Notohamiprodjo, Mike; Nikolaou, Konstantin; Bamberg, Fabian

    2015-01-01

    To compare and combine dual-energy based and iterative metal artefact reduction on hip prosthesis and dental implants in CT. A total of 46 patients (women:50%,mean age:63±15years) with dental implants or hip prostheses (n = 30/20) were included and examined with a second-generation Dual Source Scanner. 120kV equivalent mixed-images were derived from reconstructions of the 100/Sn140kV source images using no metal artefact reduction (NOMAR) and iterative metal artefact reduction (IMAR). We then generated monoenergetic extrapolations at 130keV from source images without IMAR (DEMAR) or from source images with IMAR, (IMAR+DEMAR). The degree of metal artefact was quantified for NOMAR, IMAR, DEMAR and IMAR+DEMAR using a Fourier-based method and subjectively rated on a five point Likert scale by two independent readers. In subjects with hip prosthesis, DEMAR and IMAR resulted in significantly reduced artefacts compared to standard reconstructions (33% vs. 56%; for DEMAR and IMAR; respectively, p<0.005), but the degree of artefact reduction was significantly higher for IMAR (all p<0.005). In contrast, in subjects with dental implants only IMAR showed a significant reduction of artefacts whereas DEMAR did not (71%, vs. 8% p<0.01 and p = 0.1; respectively). Furthermore, the combination of IMAR with DEMAR resulted in additionally reduced artefacts (Hip prosthesis: 47%, dental implants 18%; both p<0.0001). IMAR allows for significantly higher reduction of metal artefacts caused by hip prostheses and dental implants, compared to a dual energy based method. The combination of DE-source images with IMAR and subsequent monoenergetic extrapolation provides an incremental benefit compared to both single methods.

  4. Does aquatic exercise reduce hip and knee joint loading? In vivo load measurements with instrumented implants

    PubMed Central

    Kutzner, Ines; Dymke, Jörn; Damm, Philipp; Duda, Georg N.; Günzl, Reiner; Bergmann, Georg

    2017-01-01

    Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee) in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW). Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36–55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated individually in

  5. Osteointegration of an uncemented modular revision stem implanted during revision hip surgery.

    PubMed

    Šponer, Pavel; Kučera, Tomáš; Urban, Karel; Zítko, David; Diaz-Garcia, Daniel; Grinac, Michal

    2014-01-01

    Though mid-term survival rates of over 95% in several series have been published, there is still a paucity of related literature regarding the role of vertical stem instability in the osteointegration of fluted tapered stems. This paper presents a comprehensive and prospective assessment on short-term experiences with uncemented modular femoral stem in the treatment of defective femur during revision surgery of total hip replacement. Clinical and radiological monitoring of 20 consecutive patients with implanted tapered fluted revision stem (Lima Corporate, Udine, Italy) was of 27 months in average (20-35 months). The average pre-operative Merle d'Aubigné and Postel method score was 6.3 points (3-10 points). The frequency of femur defects, classified according to Paprosky, was IIIA = 9 and IIIB = 11. During last follow-up, the Merle d'Aubigné and Postel hip score was on average 11.7 (6-16 points). Compared to post-operation radiograph, stem migration of 1.9 mm (0-11 mm) on average was found. This vertical stem migration was observed only when comparing hip radiographs immediately after surgery, and at 6 weeks post-surgery. The Paprosky IIIA defects group, presented a subsided stem by an average of 1.5 mm. In the group of Paprosky IIIB defects, the stem subsidence was on average 2.3 mm. All 20 patients in the study showed excellent osteointegration of the uncemented revision modular stem. This study found and excellent osteointegration of the Lima uncemented tapered fluted revision modular stem in defective femur with a cortical bone segment present in the diaphyseal isthmus area. The initial vertical instability leading to stem migrating during the first six weeks following surgery did not, however, affect its osteointegration.

  6. Does aquatic exercise reduce hip and knee joint loading? In vivo load measurements with instrumented implants.

    PubMed

    Kutzner, Ines; Richter, Anja; Gordt, Katharina; Dymke, Jörn; Damm, Philipp; Duda, Georg N; Günzl, Reiner; Bergmann, Georg

    2017-01-01

    Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee) in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW). Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36-55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated individually in the

  7. A preliminary biomechanical assessment of a polymer composite hip implant using an infrared thermography technique validated by strain gage measurements.

    PubMed

    Bougherara, Habiba; Rahim, Ehsan; Shah, Suraj; Dubov, Anton; Schemitsch, Emil H; Zdero, Rad

    2011-07-01

    With the resurgence of composite materials in orthopaedic applications, a rigorous assessment of stress is needed to predict any failure of bone-implant systems. For current biomechanics research, strain gage measurements are employed to experimentally validate finite element models, which then characterize stress in the bone and implant. Our preliminary study experimentally validates a relatively new nondestructive testing technique for orthopaedic implants. Lock-in infrared (IR) thermography validated with strain gage measurements was used to investigate the stress and strain patterns in a novel composite hip implant made of carbon fiber reinforced polyamide 12 (CF/PA12). The hip implant was instrumented with strain gages and mechanically tested using average axial cyclic forces of 840 N, 1500 N, and 2100 N with the implant at an adduction angle of 15 deg to simulate the single-legged stance phase of walking gait. Three-dimensional surface stress maps were also obtained using an IR thermography camera. Results showed almost perfect agreement of IR thermography versus strain gage data with a Pearson correlation of R(2) = 0.96 and a slope = 1.01 for the line of best fit. IR thermography detected hip implant peak stresses on the inferior-medial side just distal to the neck region of 31.14 MPa (at 840 N), 72.16 MPa (at 1500 N), and 119.86 MPa (at 2100 N). There was strong correlation between IR thermography-measured stresses and force application level at key locations on the implant along the medial (R(2) = 0.99) and lateral (R(2) = 0.83 to 0.99) surface, as well as at the peak stress point (R(2) = 0.81 to 0.97). This is the first study to experimentally validate and demonstrate the use of lock-in IR thermography to obtain three-dimensional stress fields of an orthopaedic device manufactured from a composite material.

  8. Subsurface changes of a MoM hip implant below different contact zones.

    PubMed

    Pourzal, Robin; Theissmann, Ralf; Williams, Sophie; Gleising, Birgit; Fisher, John; Fischer, Alfons

    2009-04-01

    Metal-on-metal hip arthroplasties undergo distinct release of toxic metal particles and ions. Thus, it is necessary to minimize this. In order to evaluate the wear behaviour of metal-on-metal hip replacements it is essential to understand the micro-structural changes in the sub-surface region. Previous studies revealed that cobalt chromium metal-on-metal implants are able to alter their mechanical behaviour by adjusting the microstructure to load. The reason for this is the so-called mechanical mixing. This means that a nano-crystal layer is formed by rotating clusters of atoms that incorporate denatured proteins from the interfacial medium. This is followed by a layer of rhombic shaped nano-crystals in between sheared epsilon-martensite lathes, twins, and stacking faults. Although the primary wear zone has been well characterized, the sub-surface structure of the stripe wear and the non-contact zone of the hip ball have yet to be analysed. For this study a 28-mm cobalt base alloy femoral head and acetabular cup were analysed. The implant was simulator tested for 5 million cycles with the application of micro-separation resulting in a clearly visible stripe wear appearance. The TEM micrograph of the primary wear zone of the ball confirmed the presence of a sub-surface layer of nano-crystals. The thickness of this layer was approximately 200 nm and the average grain diameter ranged from 35 to 40 nm. Within the stripe wear zone the micrographs also revealed a nano-crystal layer but with a thickness of only 50 nm and an average grain diameter from 15 to 20 nm. The carbon and oxygen content was highest closest to the surface which proves the occurrence of mechanical mixing. The non-contact zone of the ball was analysed as well. When compared to the primary wear zone a nano-crystal layer with similar thickness but with an average grain diameter smaller than 15 nm was observed.

  9. A Systematic Review of Systemic Cobaltism After Wear or Corrosion of Chrome-Cobalt Hip Implants.

    PubMed

    Gessner, Bradford D; Steck, Thomas; Woelber, Erik; Tower, Stephen S

    2015-06-12

    We sought to synthesize data on systemic arthroprosthetic cobaltism, a recently described syndrome that results from wear or corrosion of chrome-cobalt hip components. We conducted a systematic literature review to identify all reported cases of systemic arthroprosthetic cobaltism. To assess the epidemiologic link between blood cobalt levels (B[Co]), we developed a symptom scoring tool that evaluated 9 different symptom categories and a category of medical utilization. We identified 25 patients reported between 2001 and 2014 with a substantial increase in case reports over the past 3 years. Symptoms were diverse and involved the hip (84%), cardiovascular system (60%), audiovestibular system (52%), peripheral motor-sensory system (48%), thyroid (48%), psychological functioning (32%), visual system (32%), and the hematological, oncological, or immune system (20%). The mean latency from implantation to presentation or revision was 41 months (range, 9-99 months). The mean B[Co] was 324 μg/L and 4 patients had levels less than 20 μg/L. The B[Co] but not blood chromium level was highly associated with a quantitative measure of overall symptom severity (r, 0.81; P < 0.001). Mean B[Co] and symptom scores were substantially higher in patients with revisions of failed ceramic-on-ceramic prostheses than those with primary metal-on-metal prostheses. Systemic arthroprosthetic cobaltism is an increasingly recognized complication of wear or corrosion of chrome-cobalt hip implants, may involve a large number of organ systems, and may occur with relatively low B[Co]. There is an urgent need to better define the overall scope of the problem and to develop screening and management strategies.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

  10. Investigation of stress shielding around the Stryker Omnifit and Exeter periprosthetic hip implants using an irreversible thermodynamic-based model.

    PubMed

    Sayyidmousavi, Alireza; Bougherara, Habiba

    2012-07-01

    This study investigates stress shielding by predicting bone density around two different implants following total hip arthroplasty using a new thermodynamic-based model for bone remodeling. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy, and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is incorporated into the finite element software ANSYS by means of a macro to investigate stress shielding around two different implants: Stryker Omnifit and Exeter periprosthetic hip stems. The results of the simulation showing bone density reductions of 17% in Gruen zone 1 and 27% in Gruen zones 7 around the Omnifit hip stem agree well with dual-energy X-ray absorptiometry (DEXA) measurements reported in the literature. On the other hand, the Exeter implant is found to result in more severe resorption in the proximal femur. This is consistent with clinical studies, which report a higher survivorship rate for HA-coated Omnifit hip stems.

  11. Effect of wear of bearing surfaces on elastohydrodynamic lubrication of metal-on-metal hip implants.

    PubMed

    Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P

    2005-09-01

    consistent with the minimal wear observed between 1 and 5 million cycles. However, under adverse in vivo conditions associated with start-up and stopping and depleted lubrication, wear of the bearing surfaces can still occur. An increase in the wear depth beyond a certain limit was shown to lead to the constriction of the lubricant film around the edge of the contact conjunction and consequently to a decrease in the lubricant film thickness. Continuous cycles of a running-in wear period followed by a steady state wear period may be inevitable in MOM hip implants. This highlights the importance of minimizing the wear in these devices during the initial running-in period, particularly from design and manufacturing points of view.

  12. Effects of Hip Implant Modular Neck Material and Assembly Method on Fatigue Life and Distraction Force.

    PubMed

    Aljenaei, Fahad; Catelas, Isabelle; Louati, Hakim; Beaulé, Paul E; Nganbe, Michel

    2016-11-16

    Hip implant neck fractures and adverse tissue reactions associated with fretting-corrosion damage at modular interfaces are a major source of concern. Therefore, there is an urgent clinical need to develop accurate in vitro test procedures to better understand, predict, and prevent in vivo implant failures. This study aimed to simulate in vivo fatigue fracture and distraction of modular necks in an in vitro setting, and to assess the effects of neck material (Ti6Al4V vs. CoCrMo) and assembly method (hand vs. impact) on the fatigue life and distraction of the necks. Fatigue tests were performed on the cementless PROFEMUR® Total Hip Modular Neck System under two different loads and number of cycles: 2.3 kN for 5 million cycles, and 7.0 kN for 1.3 million cycles. The developed in vitro simulation setup successfully reproduced in vivo modular neck fracture mode and location. Neck failure occurred at the neck-stem taper and the fracture ran from the distal lateral neck surface to the proximal medial entry point of the neck into the stem. None of the necks failed under the 2.3 kN load. However, all hand-assembled Ti6Al4V necks failed under the 7.0 kN load. In contrast, none of the hand-assembled CoCrMo necks and impact-assembled necks (Ti6Al4V or CoCrMo) failed under this higher load. In conclusion, Ti6Al4V necks were more susceptible to fatigue failure than CoCrMo necks. In addition, impact assembly substantially improved the fatigue life of Ti6Al4V necks and also led to overall higher distraction forces for both neck materials. Overall, this study shows that the material and assembly method can affect the fatigue strength of modular necks. Finally, improper implant assembly during surgery may result in diminished modular neck survivability and increased failure rates. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  13. Total hip replacement: A meta-analysis to evaluate survival of cemented, cementless and hybrid implants

    PubMed Central

    Phedy, Phedy; Ismail, H Dilogo; Hoo, Charles; Djaja, Yoshi P

    2017-01-01

    AIM To determine whether cemented, cementless, or hybrid implant was superior to the other in terms of survival rate. METHODS Systematic searches across MEDLINE, CINAHL, and Cochrane that compared cemented, cementless and hybrid total hip replacement (THR) were performed. Two independent reviewers evaluated the risk ratios of revision due to any cause, aseptic loosening, infection, and dislocation rate of each implants with a pre-determined form. The risk ratios were pooled separately for clinical trials, cohorts and registers before pooled altogether using fixed-effect model. Meta-regressions were performed to identify the source of heterogeneity. Funnel plots were analyzed. RESULTS Twenty-seven studies comprising 5 clinical trials, 9 cohorts, and 13 registers fulfilled the research criteria and analyzed. Compared to cementless THR, cemented THR have pooled RR of 0.47 (95%CI: 0.45-0.48), 0.9 (0.84-0.95), 1.29 (1.06-1.57) and 0.69 (0.6-0.79) for revision due to any reason, revision due to aseptic loosening, revision due to infection, and dislocation respectively. Compared to hybrid THR, the pooled RRs of cemented THR were 0.82 (0.76-0.89), 2.65 (1.14-6.17), 0.98 (0.7-1.38), and 0.67 (0.57-0.79) respectively. Compared to hybrid THR, cementless THR had RRs of 0.7 (0.65-0.75), 0.85 (0.49-1.5), 1.47 (0.93-2.34) and 1.13 (0.98-1.3). CONCLUSION Despite the limitations in this study, there was some tendency that cemented fixation was still superior than other types of fixation in terms of implant survival. PMID:28251071

  14. Surface Characterization of Retrieved Metal-on-Metal Total Hip Implants from Patients with Adverse Reaction to Metal Debris

    PubMed Central

    Burbano, Maria; Russell, Robert; Huo, Michael; Welch, Robert; Roy, Diana; Rodrigues, Danieli C.

    2014-01-01

    The use of metal-on-metal (MoM) total hip implants has decreased recently due to reports of high failure rates and adverse local tissue reaction (ALTR). It has been hypothesized that wear metal debris released from CoCr bearing surfaces may provoke delayed hypersensitivity reactions. The goal of this study is to evaluate the microscopic bearing surface characteristics of implants revised due to evidence of ALTR. The bearing surface of each head and cup was analyzed using multiple microscopy techniques for characterization of the surface features. The presence of severe mechanical scratching was a common characteristic found in all of the implants evaluated. Mechanical factors seemed to be the prevalent failure mode related to the appearance of ALTR with this particular set of retrieved implants. PMID:28788544

  15. Prediction of Polyethylene Wear Rates from Gait Biomechanics and Implant Positioning in Total Hip Replacement.

    PubMed

    Ardestani, Marzieh M; Amenábar Edwards, Pedro P; Wimmer, Markus A

    2017-08-01

    Patient-specific gait and surgical variables are known to play an important role in wear of total hip replacements (THR). However a rigorous model, capable of predicting wear rate based on a comprehensive set of subject-specific gait and component-positioning variables, has to our knowledge, not been reported. (1) Are there any differences between patients with high, moderate, and low wear rate in terms of gait and/or positioning variables? (2) Can we design a model to predict the wear rate based on gait and positioning variables? (3) Which group of wear factors (gait or positioning) contributes more to the wear rate? Data on patients undergoing primary unilateral THR who performed a postoperative gait test were screened for inclusion. We included patients with a 28-mm metal head and a hip cup made of noncrosslinked polyethylene (GUR 415 and 1050) from a single manufacturer (Zimmer, Inc). To calculate wear rates from radiographs, inclusion called for patients with a series of standing radiographs taken more than 1 year after surgery. Further, exclusion criteria were established to obtain reasonably reliable and homogeneous wear readings. Seventy-three (83% of included) patients met all criteria, and the final dataset consisted of 43 males and 30 females, 69 ± 10 years old, with a BMI of 27.3 ± 4.7 kg/m(2). Wear rates of these patients were determined based on the relative displacement of the femoral head with regard to the cup using a validated computer-assisted X-ray wear-analysis suite. Three groups with low (< 0.1 mm/year), moderate (0.1 to 0.2 mm/year), and high (> 0.2 mm/year) wear were established. Wear prediction followed a two-step process: (1) linear discriminant analysis to estimate the level of wear (low, moderate, or high), and (2) multiple linear and nonlinear regression modeling to predict the exact wear rate from gait and implant-positioning variables for each level of wear. There were no group differences for positioning and gait suggesting that

  16. Densitometric evaluation of bone-prosthetic counterface in hip and knee arthroplasty with modern implants

    PubMed Central

    Lepri, Andrea Cozzi; Giorgini, Marco; Signorini, Carla; Carulli, Christian; Civinini, Roberto; Brandi, Maria Luisa; Innocenti, Massimo

    2016-01-01

    Summary Introduction Recent acquisitions of the complex mechanisms of osseointegration between implants and host bone have gained attention, accordingly to the methods of evaluation of these interactions. DEXA analysis is considered an useful tool to assess such phenomena, in order to analyse in a quantitative manner the local metabolic activity of the bone, and to evaluate over the time the integration between host bone and prosthetic components. The purpose of the present study is to report about a preliminary experience in the analysis of osseointegration processes of patients undergoing a primary Total Hip Arthroplasty (THA) or a revision Total Knee Arthroplasty (rTKA). Materials and methods Thirty patients undergoing THA and nineteen undergoing rTKA were included in this study. In fifteen cases of THA a standard cementless stem was used; in the other fifteen a short cementless stem was chosen. In all cases a cementless cup was implanted. In all patients undergoing rTKA, all implants had pressfit femoral and tibial diaphyseal stems; only the femoral component and the tibial plateau were cemented. DEXA evaluation was performed preoperatively, and at 3, 6, 12, and 24 months postoperatively for rTKA, and at 6 and 12 months for THA. Results DEXA in THA showed a significant decrease at the femoral ROIs 1 and 7, and an increase in ROI 4. In rTKA a reduction of femoral BMD in R1, R7, and R4 was found, with maximum values of −13.6% in R1 and −11.89% in R7 at 24 months and a value of −2.55% in R4 at 12 months. On the tibial side, an increase in BMD R4 (with values of 2.18% still at 24 months), and a reduction in R7 (progressively lesser over the time) and in R1 (progressively higher) were found. Conclusions After a joint replacement a full adhesion of the prosthetic surface to the host bone should be achieved through a local biological process named osseointegration. In some cases this process may not fully realize, so the secondary stability of the implant may

  17. Blood Metal Ion Thresholds to Identify Patients with Metal-on-Metal Hip Implants at Risk of Adverse Reactions to Metal Debris: An External Multicenter Validation Study of Birmingham Hip Resurfacing and Corail-Pinnacle Implants.

    PubMed

    Matharu, Gulraj S; Berryman, Fiona; Judge, Andrew; Reito, Aleksi; McConnell, Jamie; Lainiala, Olli; Young, Stephen; Eskelinen, Antti; Pandit, Hemant G; Murray, David W

    2017-09-20

    The authors of recent studies have reported newly devised implant-specific blood metal ion thresholds to predict adverse reactions to metal debris (ARMD) in patients who have undergone unilateral or bilateral metal-on-metal (MoM) hip arthroplasty. These thresholds were most effective for identifying patients at low risk of ARMD. We investigated whether these newly devised blood metal ion thresholds could effectively identify patients at risk of ARMD after MoM hip arthroplasty in an external cohort of patients. We performed a validation study involving 803 MoM hip arthroplasties (323 unilateral Birmingham Hip Resurfacing [BHR], 93 bilateral BHR, and 294 unilateral Corail-Pinnacle implants) performed in 710 patients at 3 European centers. All patients underwent whole-blood metal ion sampling, and were divided into 2 groups: those with ARMD (leading to revision or identified on imaging; n = 75) and those without ARMD (n = 635). Previously devised implant-specific blood metal ion thresholds (2.15 μg/L of cobalt for unilateral BHR; 5.5 μg/L for the maximum of either cobalt or chromium for bilateral BHR; and 3.57 μg/L of cobalt for unilateral Corail-Pinnacle implants) were applied to the validation cohort, and receiver operating characteristic curve analysis was used to establish the discriminatory characteristics of each threshold. The area under the curve, sensitivity, specificity, and positive and negative predictive values for the ability of each implant-specific threshold to distinguish between patients with and without ARMD were, respectively, 89.4% (95% confidence interval [CI] = 82.8% to 96.0%), 78.9%, 86.7%, 44.1%, and 96.9% for unilateral BHR; 89.2% (CI = 81.3% to 97.1%), 70.6%, 86.8%, 54.5%, and 93.0% for bilateral BHR; and 76.9% (CI = 63.9% to 90.0%), 65.0%, 85.4%, 24.5%, and 97.1% for unilateral Corail-Pinnacle implants. Using the implant-specific thresholds, we missed 20 patients with ARMD (2.8% of the patients in this series). We missed more patients

  18. Dynamic hip screw versus DHS blade: a biomechanical comparison of the fixation achieved by each implant in bone.

    PubMed

    O'Neill, F; Condon, F; McGloughlin, T; Lenehan, B; Coffey, J C; Walsh, M

    2011-05-01

    We biomechanically investigated whether the standard dynamic hip screw (DHS) or the DHS blade achieves better fixation in bone with regard to resistance to pushout, pullout and torsional stability. The experiments were undertaken in an artificial bone substrate in the form of polyurethane foam blocks with predefined mechanical properties. Pushout tests were also repeated in cadaveric femoral heads. The results showed that the DHS blade outperformed the DHS with regard to the two most important characteristics of implant fixation, namely resistance to pushout and rotational stability. We concluded that the DHS blade was the superior implant in this study.

  19. Contact mechanics and elastohydrodynamic lubrication in a novel metal-on-metal hip implant with an aspherical bearing surface.

    PubMed

    Meng, Qingen; Gao, Leiming; Liu, Feng; Yang, Peiran; Fisher, John; Jin, Zhongmin

    2010-03-22

    Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the radius of the curvature of a bearing surface and consequently improving the conformity between the head and the cup. In this study, a novel metal-on-metal hip implant employing a specific aspherical bearing surface, Alpharabola, as the acetabular surface was investigated for both contact mechanics and elastohydrodynamic lubrication under steady-state conditions. When compared with conventional spherical bearing surfaces, a more uniform pressure distribution and a thicker lubricant film thickness within the loaded conjunction were predicted for this novel Alpharabola hip implant. The effects of the geometric parameters of this novel acetabular surface on the pressure distribution and lubricant thickness were investigated. A significant increase in the predicted lubricant film thickness and a significant decrease in the dry contact and hydrodynamic pressures were found with appropriate combinations of these geometric parameters, compared with the spherical bearing surface.

  20. In vivo severe corrosion and hydrogen embrittlement of retrieved modular body titanium alloy hip-implants.

    PubMed

    Rodrigues, Danieli C; Urban, Robert M; Jacobs, Joshua J; Gilbert, Jeremy L

    2009-01-01

    Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity, and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination, and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion.

  1. IN VIVO SEVERE CORROSION AND HYDROGEN EMBRITTLEMENT OF RETRIEVED MODULAR BODY TITANIUM ALLOY HIP-IMPLANTS

    PubMed Central

    Rodrigues, Danieli C.; Urban, Robert M.; Jacobs, Joshua J.; Gilbert, Jeremy L.

    2009-01-01

    Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), x-ray diffraction (XRD) and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion. PMID:18683224

  2. The Effects of Interlocking a Universal Hip Cementless Stem on Implant Subsidence and Mechanical Properties of Cadaveric Canine Femora

    PubMed Central

    Buks, Yonathan; Stover, Susan M.; Garcia‐Nolen, Tanya C.

    2016-01-01

    Objective To determine if an interlocking bolt would limit subsidence of the biological fixation universal hip (BFX®) femoral stem under cyclic loading and enhance construct stiffness, yield, and failure properties. Study Design Ex vivo biomechanical study. Animals Cadaveric canine femora (10 pairs). Methods Paired femora implanted with a traditional stem or an interlocking stem (constructs) were cyclically loaded at walk, trot, and gallop loads while implant and bone motions were captured using kinematic markers and high‐speed video. Constructs were then loaded to failure to evaluate failure mechanical properties. Results Implant subsidence was greater (P = .037) for the traditional implant (4.19 mm) than the interlocking implant (0.78 mm) only after gallop cyclic loading, and cumulatively after walk, trot, and gallop cyclic loads (5.20 mm vs. 1.28 mm, P = .038). Yield and failure loads were greater (P = .029 and .002, respectively) for the interlocking stem construct (1155 N and 2337 N) than the traditional stem construct (816 N and 1405 N). Version angle change after cyclic loading was greater (P = .020) for the traditional implant (3.89 degrees) than for the interlocking implant (0.16 degrees), whereas stem varus displacement at failure was greater (P = .008) for the interlocking implant (1.5 degrees) than the traditional implant (0.17 degrees). Conclusion Addition of a stabilizing bolt enhanced construct stability and limited subsidence of a BFX® femoral stem. Use of the interlocking implant may decrease postoperative subsidence. However, in vivo effects of the interlocking bolt on osseointegration, bone remodeling, and stress shielding are unknown. PMID:26767439

  3. The Effects of Interlocking a Universal Hip Cementless Stem on Implant Subsidence and Mechanical Properties of Cadaveric Canine Femora.

    PubMed

    Buks, Yonathan; Wendelburg, Kirk L; Stover, Susan M; Garcia-Nolen, Tanya C

    2016-02-01

    To determine if an interlocking bolt would limit subsidence of the biological fixation universal hip (BFX(®)) femoral stem under cyclic loading and enhance construct stiffness, yield, and failure properties. Ex vivo biomechanical study. Cadaveric canine femora (10 pairs). Paired femora implanted with a traditional stem or an interlocking stem (constructs) were cyclically loaded at walk, trot, and gallop loads while implant and bone motions were captured using kinematic markers and high-speed video. Constructs were then loaded to failure to evaluate failure mechanical properties. Implant subsidence was greater (P = .037) for the traditional implant (4.19 mm) than the interlocking implant (0.78 mm) only after gallop cyclic loading, and cumulatively after walk, trot, and gallop cyclic loads (5.20 mm vs. 1.28 mm, P = .038). Yield and failure loads were greater (P = .029 and .002, respectively) for the interlocking stem construct (1155 N and 2337 N) than the traditional stem construct (816 N and 1405 N). Version angle change after cyclic loading was greater (P = .020) for the traditional implant (3.89 degrees) than for the interlocking implant (0.16 degrees), whereas stem varus displacement at failure was greater (P = .008) for the interlocking implant (1.5 degrees) than the traditional implant (0.17 degrees). Addition of a stabilizing bolt enhanced construct stability and limited subsidence of a BFX(®) femoral stem. Use of the interlocking implant may decrease postoperative subsidence. However, in vivo effects of the interlocking bolt on osseointegration, bone remodeling, and stress shielding are unknown. © Copyright 2016 by The American College of Veterinary Surgeons.

  4. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  5. Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients

    NASA Astrophysics Data System (ADS)

    Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang

    2016-06-01

    Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints.

  6. Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients

    PubMed Central

    Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang

    2016-01-01

    Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints. PMID:27345704

  7. Wear behaviour of cobalt-chromium-molybdenum alloys used in metal-on-metal hip implants

    NASA Astrophysics Data System (ADS)

    Varano, Rocco

    The influence of carbon (C) content, microstructure, crystallography and mechanical properties on the wear behaviour of metal-on-metal (MM) hip implants made from commercially available cobalt-chromium-molybdenum (CoCrMo) alloys designated as American Society of Testing and Materials (ASTM) grade F1537, F75 and as-cast were studied in this work. The as-received bars of wrought CoCrMo alloys (ASTM F1537 of either about 0.05% or 0.26% C) were each subjected to various heat treatments to develop different microstructures. Pin and plate specimens were fabricated from each bar and were tested against each other using a linear reciprocating pin-on-plate apparatus in 25% by volume bovine serum solution. The applied normal load was 9.81 N and the reciprocating plate had a sinusoidal velocity with an average speed of 26 mm/s. The wear was measured gravimetrically and it was found to be most strongly affected by alloy C content, irrespective of grain size or carbide morphology. More precisely, the wear behaviour was directly correlated to the dissolved C content of the alloys. Increased C in solid-solution coincided with lower volumetric wear since C helps to stabilize the face-centred cubic (FCC) crystal structure thus limiting the amount of strain induced transformation (SIT) to the hexagonal close-packed crystal structure (HCP). Based on the observed surface twinning in and around the contact zone and the potentially detrimental effect of the HCP phase, it was postulated that the MM wear behaviour of CoCrMo alloys in the present study was controlled by a deformation mechanism, rather than corrosion or tribochemical reactions.

  8. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

    PubMed Central

    Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  9. Successful staged hip replacement in septic hip osteoarthritis in osteopetrosis: a case report

    PubMed Central

    2012-01-01

    Background Osteopetrosis is a rare, inherited, bone disorder, characterized by osteosclerosis, obliteration of the medullary cavity and calcified cartilage. The autosomal dominant form is compatible with a normal life span, although fractures often result from minimal trauma, due to the pathologic nature of bone. Osteomyelitis is common in patients with osteopetrosis because of a reduced resistance to infection, attributed to the lack of marrow vascularity and impairment of white cell function. Only one case of osteomyelitis of the proximal third of the femur has been previously reported, treated with several repeated debridements and finally with femoral head resection. Here we present for the first time a case of a staged implant of a cementless total hip prosthesis for the treatment of a septic hip in femoral neck nonunion in osteopetrosis. Case presentation A 36-years-old woman, affected by autosomal dominant osteopetrosis was referred to our department because of a septic hip arthritis associated with femoral neck septic non-union, with draining fistulas. The infection occurred early after a plate osteosynthesis for a closed perthrocanteric fracture of the femur and persisted in spite of osteosynthesis removal, surgical debridement and external fixation. In our hospital the patient underwent accurate debridement, femoral head and greater trochanter resection, preparation of the diaphyseal intramedullary canal and implant of an antibiotic-loaded cement spacer. The spacer was exchanged after one month, due to infection recurrence and four months later, a cementless total hip arthroplasty was implanted, with no clinical and laboratory signs of infection recurrence at two years follow-up. Conclusions In case of hip septic arthritis and proximal femur septic non-union, femoral head resection may not be the only option available and staged total hip arthroplasty can be considered. PMID:22472060

  10. Comparison of robotic-assisted and manual implantation of a primary total hip replacement. A prospective study.

    PubMed

    Honl, Matthias; Dierk, Oliver; Gauck, Christian; Carrero, Volker; Lampe, Frank; Dries, Sebastian; Quante, Markus; Schwieger, Karsten; Hille, Ekkehard; Morlock, Michael M

    2003-08-01

    Robotic-assisted total hip replacement has become a common method of implantation, especially in Europe. It frequently has been postulated that robotic reaming would result in an improved clinical outcome due to the better fit of the prosthesis, but that has never been demonstrated in a prospective study, to our knowledge. The purpose of this study was to compare robotic-assisted implantation of a total hip replacement with conventional manual implantation. One hundred and fifty-four patients scheduled for total hip replacement were randomly assigned to undergo either conventional manual implantation of an S-ROM prosthesis (eighty patients) or robotic-assisted implantation of such a prosthesis (seventy-four patients). The five-axis ROBODOC was used for the robotic-assisted procedures. Preoperatively as well as at three, six, twelve, and twenty-four months after surgery, the scores according to the Harris and Merle d'Aubigné systems and the Mayo clinical score were determined. Radiographs made at these intervals were analyzed for evidence of loosening, prosthetic alignment, and heterotopic ossification. Thirteen (18%) of the seventy-four attempted robotic implantations had to be converted to manual implantations as a result of failure of the system. The duration of the robotic procedures was longer than that of the manual procedures (mean and standard deviation,107.1 +/- 29.1 compared with 82.4 +/- 23.4 minutes, p < 0.001). Limb-length equality (mean discrepancy, 0.18 +/- 0.30 compared with 0.96 +/- 0.93 cm, p < 0.001) and varus-valgus orientation of the stem (mean angle between the femur and the shaft of the prosthesis, 0.34 degrees +/- 0.67 degrees compared with 0.84 degrees +/- 1.23 degrees, p < 0.001) were better after the robotic procedures. At six months, slightly more heterotopic ossification was seen in the group treated with robotic implantation. The group treated with robotic implantation had a better Mayo clinical score at six and twelve months and a

  11. No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

    PubMed Central

    Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

    2014-01-01

    Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the

  12. Toxicology-based cancer causation analysis of CoCr-containing hip implants: a quantitative assessment of genotoxicity and tumorigenicity studies.

    PubMed

    Christian, Whitney V; Oliver, Lindsay D; Paustenbach, Dennis J; Kreider, Marisa L; Finley, Brent L

    2014-09-01

    In this paper, quantitative methods were used to evaluate the weight of evidence regarding a causative relationship between cobalt-chromium (CoCr)-containing hip implants and increased cancer risk. We reviewed approximately 80 published papers and identified no-observed-adverse-effect level (NOAEL) and/or lowest-observed-adverse-effect level (LOAEL) values for specific endpoints of interest: genotoxic effects from in vitro studies with human cell lines as well as genotoxicity and tumor formation in animal bioassays. Test articles included Co particles and ions, Cr particles and ions, and CoCr alloy particles as well as CoCr alloy implants. The NOAEL/LOAEL values were compared with body burdens of Co/Cr particles and ions we calculated to exist in systemic tissues of hip implant patients under normal and excessive wear conditions. We found that approximately 40 tumor bioassays have been conducted with CoCr alloy implants or Co/Cr particles and ions at levels hundreds to thousands of times higher than those present in hip implant patients, and none reported a statistically significant increased incidence of systemic tumors. Results from in vitro and in vivo genotoxicity assays, which are relatively less informative owing to false positives and other factors, also indicated that DNA effects would be highly unlikely to occur as a result of wear debris from a CoCr implant. Hence, the toxicological weight of evidence suggests that CoCr-containing hip implants are unlikely to be associated with an increased risk of systemic cancers, which is consistent with published and ongoing cancer epidemiology studies involving patients with CoCr hip implants. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Fretting-corrosion in Hip Implant Modular Junctions: New Experimental Set-up and Initial Outcome

    PubMed Central

    Royhman, D.; Patel, M.; Runa, M.J.; Jacobs, J.J.; Hallab, N.J.; Wimmer, M.A.; Mathew, M.T.

    2015-01-01

    Modern hip prostheses feature a modular implant design with at least one tapered junction. This design can lead to several complications due to the introduction of additional interfaces, which are subjected to various loading conditions and micromotion. The main objective of current study is to develop a fretting corrosion apparatus, which is able characterize the mechanical and electrochemical behaviour of various existing metal alloy couples during fretting motion. This study describes the design and the main considerations during the development of a novel fretting corrosion apparatus, as well as determination of the machine compliance and the initial testing results. Machine compliance considerations and frictional interactions of the couples are discussed in detail. For the preliminary tests, metal alloy pins, made of Ti6Al4V and wrought high-carbon CoCrMo were mechanically polished to a surface roughness of less than 20nm. 2 pins (Diameter = 11mm) of either Ti6Al4V or CoCrMo were loaded onto a Ti6Al4V alloy rod at a normal force of 200N. The interface types included: Ti6Al4V-Ti6Al4V-Ti6Al4V, Ti6Al4V-Ti6Al4V-CoCrMo, and CoCrMo-Ti6Al4V-CoCrMo. The Ti6Al4V rod articulated against the metal alloy pins in a sinusoidal fretting motion with a displacement amplitude of ±50μm. Bovine calf serum (30g/L of protein content) was selected as a lubricant and tested at 2 different pH levels (pH 3.0 and 7.6). In all cases, current and friction energy were monitored during the fretting process. The results indicated distinct, material-specific current evolutions and friction energies. No significant differences were observed in electrochemical or mechanical behaviour in response to pH change. In general, Ti6Al4V-Ti6Al4V-Ti6Al4V couples displayed the earliest passivation and superior electrochemical behaviour compared to Ti6Al4V-Ti6Al4V-CoCrMo and CoCrMo-Ti6Al4V-CoCrMo under fretting conditions. In addition, fluctuations in current were observed in specific regions at all

  14. Fretting-corrosion in Hip Implant Modular Junctions: New Experimental Set-up and Initial Outcome.

    PubMed

    Royhman, D; Patel, M; Runa, M J; Jacobs, J J; Hallab, N J; Wimmer, M A; Mathew, M T

    2015-11-01

    Modern hip prostheses feature a modular implant design with at least one tapered junction. This design can lead to several complications due to the introduction of additional interfaces, which are subjected to various loading conditions and micromotion. The main objective of current study is to develop a fretting corrosion apparatus, which is able characterize the mechanical and electrochemical behaviour of various existing metal alloy couples during fretting motion. This study describes the design and the main considerations during the development of a novel fretting corrosion apparatus, as well as determination of the machine compliance and the initial testing results. Machine compliance considerations and frictional interactions of the couples are discussed in detail. For the preliminary tests, metal alloy pins, made of Ti6Al4V and wrought high-carbon CoCrMo were mechanically polished to a surface roughness of less than 20nm. 2 pins (Diameter = 11mm) of either Ti6Al4V or CoCrMo were loaded onto a Ti6Al4V alloy rod at a normal force of 200N. The interface types included: Ti6Al4V-Ti6Al4V-Ti6Al4V, Ti6Al4V-Ti6Al4V-CoCrMo, and CoCrMo-Ti6Al4V-CoCrMo. The Ti6Al4V rod articulated against the metal alloy pins in a sinusoidal fretting motion with a displacement amplitude of ±50μm. Bovine calf serum (30g/L of protein content) was selected as a lubricant and tested at 2 different pH levels (pH 3.0 and 7.6). In all cases, current and friction energy were monitored during the fretting process. The results indicated distinct, material-specific current evolutions and friction energies. No significant differences were observed in electrochemical or mechanical behaviour in response to pH change. In general, Ti6Al4V-Ti6Al4V-Ti6Al4V couples displayed the earliest passivation and superior electrochemical behaviour compared to Ti6Al4V-Ti6Al4V-CoCrMo and CoCrMo-Ti6Al4V-CoCrMo under fretting conditions. In addition, fluctuations in current were observed in specific regions at all

  15. The Cost-Effectiveness of Dual Mobility Implants for Primary Total Hip Arthroplasty: A Computer-Based Cost-Utility Model.

    PubMed

    Barlow, Brian T; McLawhorn, Alexander S; Westrich, Geoffrey H

    2017-05-03

    Dislocation remains a clinically important problem following primary total hip arthroplasty, and it is a common reason for revision total hip arthroplasty. Dual mobility (DM) implants decrease the risk of dislocation but can be more expensive than conventional implants and have idiosyncratic failure mechanisms. The purpose of this study was to investigate the cost-effectiveness of DM implants compared with conventional bearings for primary total hip arthroplasty. Markov model analysis was conducted from the societal perspective with use of direct and indirect costs. Costs, expressed in 2013 U.S. dollars, were derived from the literature, the National Inpatient Sample, and the Centers for Medicare & Medicaid Services. Effectiveness was expressed in quality-adjusted life years (QALYs). The model was populated with health state utilities and state transition probabilities derived from previously published literature. The analysis was performed for a patient's lifetime, and costs and effectiveness were discounted at 3% annually. The principal outcome was the incremental cost-effectiveness ratio (ICER), with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to explore relevant uncertainty. In the base case, DM total hip arthroplasty showed absolute dominance over conventional total hip arthroplasty, with lower accrued costs ($39,008 versus $40,031 U.S. dollars) and higher accrued utility (13.18 versus 13.13 QALYs) indicating cost-savings. DM total hip arthroplasty ceased being cost-saving when its implant costs exceeded those of conventional total hip arthroplasty by $1,023, and the cost-effectiveness threshold for DM implants was $5,287 greater than that for conventional implants. DM was not cost-effective when the annualized incremental probability of revision from any unforeseen failure mechanism or mechanisms exceeded 0.29%. The probability of intraprosthetic dislocation exerted the most influence on model results. This model

  16. Are all metal-on-metal hip revision operations contributing to the National Joint Registry implant survival curves?

    PubMed Central

    Sabah, S. A.; Henckel, J.; Koutsouris, S.; Rajani, R.; Hothi, H.; Skinner, J. A.; Hart, A. J.

    2016-01-01

    Aims The National Joint Registry for England, Wales and Northern Ireland (NJR) has extended its scope to report on hospital, surgeon and implant performance. Data linkage of the NJR to the London Implant Retrieval Centre (LIRC) has previously evaluated data quality for hip primary procedures, but did not assess revision records. Methods We analysed metal-on-metal hip revision procedures performed between 2003 and 2013. A total of 69 929 revision procedures from the NJR and 929 revised pairs of components from the LIRC were included. Results We were able to link 716 (77.1%) revision procedures on the NJR to the LIRC. This meant that 213 (22.9%) revision procedures at the LIRC could not be identified on the NJR. We found that 349 (37.6%) explants at the LIRC completed the full linkage process to both NJR primary and revision databases. Data completion was excellent (> 99.9%) for revision procedures reported to the NJR. Discussion This study has shown that only approximately one third of retrieved components at the LIRC, contributed to survival curves on the NJR. We recommend prospective registry-retrieval linkage as a tool to feedback missing and erroneous data to the NJR and improve data quality. Take home message: Prospective Registry – retrieval linkage is a simple tool to evaluate and improve data quality on the NJR. Cite this article: Bone Joint J 2016;98-B:33–9. PMID:26733513

  17. A biomechanical testing system to determine micromotion between hip implant and femur accounting for deformation of the hip implant: Assessment of the influence of rigid body assumptions on micromotions measurements.

    PubMed

    Leuridan, Steven; Goossens, Quentin; Roosen, Jorg; Pastrav, Leonard; Denis, Kathleen; Mulier, Michiel; Desmet, Wim; Vander Sloten, Jos

    2017-02-01

    Accurate pre-clinical evaluation of the initial stability of new cementless hip stems using in vitro micromotion measurements is an important step in the design process to assess the new stem's potential. Several measuring systems, linear variable displacement transducer-based and other, require assuming bone or implant to be rigid to obtain micromotion values or to calculate derived quantities such as relative implant tilting. An alternative linear variable displacement transducer-based measuring system not requiring a rigid body assumption was developed in this study. The system combined advantages of local unidirectional and frame-and-bracket micromotion measuring concepts. The influence and possible errors that would be made by adopting a rigid body assumption were quantified. Furthermore, as the system allowed emulating local unidirectional and frame-and-bracket systems, the influence of adopting rigid body assumptions were also analyzed for both concepts. Synthetic and embalmed bone models were tested in combination with primary and revision implants. Single-legged stance phase loading was applied to the implant - bone constructs. Adopting a rigid body assumption resulted in an overestimation of mediolateral micromotion of up to 49.7μm at more distal measuring locations. Maximal average relative rotational motion was overestimated by 0.12° around the anteroposterior axis. Frontal and sagittal tilting calculations based on a unidirectional measuring concept underestimated the true tilting by an order of magnitude. Non-rigid behavior is a factor that should not be dismissed in micromotion stability evaluations of primary and revision femoral implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Information for Patients Who Have Metal-on-Metal Hip Implants

    MedlinePlus

    ... their implants. These problems included: General hypersensitivity reaction (skin rash) Cardiomyopathy Neurological changes including sensory changes (auditory, or visual impairments) Psychological status change ( ...

  19. Incidence of Modern Alumina Ceramic and Alumina Matrix Composite Femoral Head Failures in Nearly 6 Million Hip Implants.

    PubMed

    Lee, Gwo-Chin; Kim, Raymond H

    2017-02-01

    Because of improvements in ceramic materials and manufacturing, the incidence of ceramic failures has decreased over time. Recent concerns with corrosion have contributed to an increase in ceramic ball head utilization. The purpose of this study is to report the incidence of modern alumina bearing failures from a single major ceramic manufacturer in nearly 6 million hip implants and to identify trends in the modes of failure of these implants. Beginning in the year 2000, CeramTec AG (Plochingen, Germany) began a comprehensive program for reporting and gathering failure data on its products. From January 1, 2000, to December 31, 2013, over 3.2 million pure alumina (PA) and 2.78 million alumina matrix composite (AMC) ceramic ball heads were implanted worldwide. During this period, there were 672 PA and 28 AMC femoral head fractures. The fractures were analyzed with respect to time to failure, head size, and implant factors. The incidence of clinical fractures of modern PA femoral heads and AMC femoral heads was 1 in 5000 (0.0201%) and 1 in 100,000 (0.0010%), respectively (P < .0001). The majority of implant failures (80%) occurred within 48 months following surgery (P < .01). Fractures were usually associated with specific events such as trauma, mismatched components, and dislocations. Large-diameter PA heads were associated with a lower rate of fracture compared to smaller-diameter femoral heads (0.0316% for 28-mm heads vs 0.0080% for heads 32 mm or greater [P < .01]). Similar trends were observed with AMC heads. The neck lengths of the femoral ball heads were also a factor: a short-taper 28-mm ball head was more likely to fracture compared to other neck lengths (P < .01). Modern PA ceramic heads are reliable with extremely low risk of fracture. The reliability is even better with AMC heads. Copyright © 2016. Published by Elsevier Inc.

  20. The manufacture of generic replicas of implants for arthroplasty of the hip and knee: is it regulated and will it save money?

    PubMed

    Atrey, A; Heylen, S; Gosling, O; Porteous, M J L; Haddad, F S

    2016-07-01

    Joint replacement of the hip and knee remain very satisfactory operations. They are, however, expensive. The actual manufacturing of the implant represents only 30% of the final cost, while sales and marketing represent 40%. Recently, the patents on many well established and successful implants have expired. Companies have started producing and distributing implants that purport to replicate existing implants with good long-term results. The aims of this paper are to assess the legality, the monitoring and cost saving implications of such generic implants. We also assess how this might affect the traditional orthopaedic implant companies. Cite this article: Bone Joint J 2016;98-B:892-900. ©2016 The British Editorial Society of Bone & Joint Surgery.

  1. Distributed analysis of hip implants using six national and regional registries: comparing metal-on-metal with metal-on-highly cross-linked polyethylene bearings in cementless total hip arthroplasty in young patients.

    PubMed

    Furnes, Ove; Paxton, Elizabeth; Cafri, Guy; Graves, Stephen; Bordini, Barbara; Comfort, Thomas; Rivas, Moises Coll; Banerjee, Samprit; Sedrakyan, Art

    2014-12-17

    The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival probabilities was performed with use of a fixed-effects model. Metal-on-metal implants with a large head size of >36 mm were compared with metal-on-highly cross-linked polyethylene implants. Metal-on-metal implants with a large head size of >36 mm were used in 5172 hips and metal-on-highly cross-linked polyethylene implants were used in 14,372 hips. Metal-on-metal total hip replacements with a large head size of >36 mm had an increased risk of revision compared with metal-on-highly cross-linked polyethylene total hip replacements with more than two years of follow-up, with no difference during the first two years after implantation. The results of the hazard ratios (and 95% confidence intervals) from the multivariable model at various durations of follow-up were 0.95 (0.74 to 1.23) at zero to two years (p = 0.698), 1.42 (1.16 to 1.75) at more than two years to four years (p = 0.001), 1.78 (1.45 to 2.19) at more than four years to six years (p < 0.001), and 2.15 (1.63 to 2.83) at more than

  2. Distributed Analysis of Hip Implants Using Six National and Regional Registries: Comparing Metal-on-Metal with Metal-on-Highly Cross-Linked Polyethylene Bearings in Cementless Total Hip Arthroplasty in Young Patients

    PubMed Central

    Furnes, Ove; Paxton, Elizabeth; Cafri, Guy; Graves, Stephen; Bordini, Barbara; Comfort, Thomas; Rivas, Moises Coll; Banerjee, Samprit; Sedrakyan, Art

    2014-01-01

    Background: The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Methods: Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival probabilities was performed with use of a fixed-effects model. Metal-on-metal implants with a large head size of >36 mm were compared with metal-on-highly cross-linked polyethylene implants. Results: Metal-on-metal implants with a large head size of >36 mm were used in 5172 hips and metal-on-highly cross-linked polyethylene implants were used in 14,372 hips. Metal-on-metal total hip replacements with a large head size of >36 mm had an increased risk of revision compared with metal-on-highly cross-linked polyethylene total hip replacements with more than two years of follow-up, with no difference during the first two years after implantation. The results of the hazard ratios (and 95% confidence intervals) from the multivariable model at various durations of follow-up were 0.95 (0.74 to 1.23) at zero to two years (p = 0.698), 1.42 (1.16 to 1.75) at more than two years to four years (p = 0.001), 1.78 (1.45 to 2.19) at more than four years to six years (p < 0.001), and 2

  3. Optimization of Scan Time in MRI for Total Hip Prostheses: SEMAC Tailoring for Prosthetic Implants Containing Different Types of Metals.

    PubMed

    Deligianni, X; Bieri, O; Elke, R; Wischer, T; Egelhof, T

    2015-12-01

    Magnetic resonance imaging (MRI) of soft tissues after total hip arthroplasty is of clinical interest for the diagnosis of various pathologies that are usually invisible with other imaging modalities. As a result, considerable effort has been put into the development of metal artifact reduction MRI strategies, such as slice encoding for metal artifact correction (SEMAC). Generally, the degree of metal artifact reduction with SEMAC directly relates to the overall time spent for acquisition, but there is no specific consensus about the most efficient sequence setup depending on the implant material. The aim of this article is to suggest material-tailored SEMAC protocol settings. Five of the most common total hip prostheses (1. Revision prosthesis (S-Rom), 2. Titanium alloy, 3. Müller type (CoNiCRMo alloy), 4. Old Charnley prosthesis (Exeter/Stryker), 5. MS-30 stem (stainless-steel)) were scanned on a 1.5 T MRI clinical scanner with a SEMAC sequence with a range of artifact-resolving slice encoding steps (SES: 2-23) along the slice direction (yielding a total variable scan time ranging from 1 to 10 min). The reduction of the artifact volume in comparison with maximal artifact suppression was evaluated both quantitatively and qualitatively in order to establish a recommended number of steps for each case. The number of SES that reduced the artifact volume below approximately 300 mm(3) ranged from 3 to 13, depending on the material. Our results showed that although 3 SES steps can be sufficient for artifact reduction for titanium prostheses, at least 11 SES should be used for prostheses made of materials such as certain alloys of stainless steel. Tailoring SES to the implant material and to the desired degree of metal artifact reduction represents a simple tool for workflow optimization of SEMAC imaging near total hip arthroplasty in a clinical setting. Five of the most common total hip prostheses have been investigated in vitro. Tailored SEMAC protocols - in terms of

  4. The biomechanical effect of anteversion and modular neck offset on stress shielding for short-stem versus conventional long-stem hip implants.

    PubMed

    Goshulak, Peter; Samiezadeh, Saeid; Aziz, Mina S R; Bougherara, Habiba; Zdero, Radovan; Schemitsch, Emil H

    2016-03-01

    Short-stem hip implants are increasingly common since they preserve host bone stock and presumably reduce stress shielding by improving load distribution in the proximal femur. Stress shielding may lead to decreased bone density, implant loosening, and fracture. However, few biomechanical studies have examined short-stem hip implants. The purpose of this study was to compare short-stem vs. standard length stemmed implants for stress shielding effects due to anteversion-retroversion, anterior-posterior position, and modular neck offset. Twelve artificial femurs were implanted with either a short-stem modular-neck implant or a conventional length monolithic implant in 0° or 15° of anteversion. Three modular neck options were tested in the short-stem implants. Three control femurs remained intact. Femurs were mounted in adduction and subjected to axial loading. Strain gauge values were collected to validate a Finite Element (FE) model, which was used to simulate the full range of physiologically possible anteversion and anterior-posterior combinations (n = 25 combinations per implant). Calcar stress was compared between implants and across each implant's range of anteversion using one and two-way ANOVA. Stress shielding was defined as the overall change in stress compared to an intact femur. The FE model compared well with experimental strains (intact: slope = 0.898, R = 0.943; short-stem: slope = 0.731, R = 0.948; standard-stem: slope = 0.743, R = 0.859); correction factors were used to adjust slopes to unity. No implant anteversion showed significant reduction in stress shielding (α = 0.05, p > 0.05). Stress shielding was significantly higher in the standard-stem implant (63% change from intact femur, p < 0.001) than in short-stem implants (29-39% change, p < 0.001). Short-stem implants reduce stress shielding compared to standard length stemmed implants, while implant anteversion and anterior-posterior position had no effect. Therefore, short-stem implants have

  5. [Alveolar ridge augmentation with hip corticocancellous allogenic block graft prior to implant placement].

    PubMed

    Dori, S; Peleg, M; Barnea, E

    2008-07-01

    The use of autogenous block bone grafts in bone regeneration procedures for alveolar ridge augmentation can be limited by donor-site morbidity and complications. In this study, allogeneic block grafts were used for ridge augmentation prior to implant placement. Thirty six patients with severe ridge width and height deficiency underwent augmentation using an allogeneic corticocancellous iliac block bone graft. After rigid fixation of the graft, the site was covered with a freeze dried allogeneic dura mater membrane or restorable collagen membrane and then tension-free closure was performed. Implants were placed three to four months after surgery. Three to six months after implant placement, panoramic radiographs were taken and implants were uncovered for prosthetic restoration. Out of the 70 implants placed, one implant failed to integrate. Out of the 49 grafts placed one graft showed three millimeters of bone resorbtion at the superior buccal aspect of the graft. No other clinical problems were observed. The block grafts were clinically well integrated into the recipient site. The augmented bone remained stable throughout implant placement procedures. Clinical outcome evidence demonstrates that allogeneic block bone grafts in conjunction with G.B.R principles might be a viable alternative to autogenous grafts in selected patients with alveolar ridge deficiencies.

  6. Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

    PubMed

    Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

    2017-05-08

    Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (<100 nm) to submicron (<1000 nm) size range, whereas edge-loading conditions generated particles that ranged from <100 nm up to 3000-6000 nm in size. Particles isolated from normal wear were primarily chromium (98.5%) and round to oval in shape. Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  7. Clinical usefulness of blood metal measurements to assess the failure of metal-on-metal hip implants

    PubMed Central

    Sampson, Barry; Hart, Alister

    2012-01-01

    In April 2010, a Medicines and Healthcare Products Regulatory Agency safety alert concerning all metal-on-metal (MOM) hip replacements recommended measuring chromium and cobalt concentrations when managing patients with painful prostheses. The need for this review is illustrated by the recent surge in requests for these blood tests from orthopaedic surgeons following this alert. The aim is to provide guidance to laboratories in assessing these requests and advising clinicians on interpretation. First, we summarize the basic terminology regarding the types of hip replacements, with emphasis on the MOM type. Second, we describe the clinical concerns over implant-derived wear debris in the local tissues and distant sites. Analytical aspects of the measurement of the relevant metal ions and what factors affect the levels measured are discussed. The application of inductively coupled plasma mass spectrometry techniques to the measurement of these metals is considered in detail. The biological effects of metal wear products are summarized with local toxicity and systemic biological effects considered, including carcinogenicity, genotoxicity and systemic toxicity. Clinical cases are used to illustrate pertinent points. PMID:22155921

  8. Infection in periprosthetic hip fractures.

    PubMed

    Cabral, Rui

    2012-01-01

    Fracture around the acetabulum and femur in total hip arthroplasty is a possible complication, sometimes with difficult surgical solution, namely when a sepsis is present. Periprosthetic hip fractures were classified according to a modified Vancouver classification. We treated 112 patients (67 men and 45 women) with periprosthetic hip fractures: 105 femoral fractures (94%) and seven acetabular fractures (6%). Mean follow-up was 10.6 years. For Type A (seven cases - 7%), B1 (10 cases - 10%) or C (13 cases - 12%) fractures around well fixed femoral stems we only fixed the fractures. For Type B2 (17 cases - 16%), B3 (46 cases - 44%) and D (12 cases - 11%, with associated fractures, not contemplated in the Vancouver classification) we used an uncemented long femoral stem, fixation with metallic cables and cancellous bone allografts to fill the femoral bone loss. We observed a deep infection in three patients (2.7%), three early hip dislocations treated by closed reductions, two cases with asymptomatic trochanteric non-union and one femoral refracture. In the three infection cases we performed two-stage revision with cementless hip prosthesis, using an antibiotic-loaded cement hip spacer (three to eight months), a six weeks period of parenteral antibiotics and we performed articular aspiration before revision surgery. Until now, we did not observe any re-infection. It is very important to make an early diagnosis, isolate micro-organisms and ensure their antibiotic susceptibility. The surgery solution depends on the well fixed implants and periprosthetic osteolysis and articular instability.

  9. Factors influencing patients' willingness to pay for new technologies in hip and knee implants.

    PubMed

    Schwarzkopf, Ran; Sagebin, Fabio M; Karia, Raj; Koenig, Karl M; Bosco, Joseph A; Slover, James D

    2013-03-01

    Rising implant prices and evolving technologies are important factors contributing to the increased cost of arthroplasty. Assessing how patients value arthroplasty, new technologies, and their perceived outcomes is critical in planning cost-effective care, as well as evaluating new-technologies. One hundred one patients undergoing arthroplasty took part in the survey. We captured demographics, spending practices, knowledge of implants, patient willingness to pay for implants, and preferences related to implant attributes. When patients were asked if they would be satisfied with "standard of care" prosthesis, 80% replied "no". When asked if they would pay for a higher than "standard of care" prosthesis, 86% replied "yes". The study demonstrated that patients, regardless of their socio-economic status, are not satisfied with standard of care implants when newer technologies are available, and they may be willing to share in the cost of their prosthesis. Patients also prefer the option to choose what they perceive to be a higher quality or innovative implant even if the "out of pocket" cost is higher.

  10. Implant survival of the most common cemented total hip devices from the Nordic Arthroplasty Register Association database

    PubMed Central

    Junnila, Mika; Laaksonen, Inari; Eskelinen, Antti; Pulkkinen, Pekka; Ivar Havelin, Leif; Furnes, Ove; Marie Fenstad, Anne; Pedersen, Alma B; Overgaard, Søren; Kärrholm, Johan; Garellick, Göran; Malchau, Henrik; Mäkelä, Keijo T

    2016-01-01

    Background and purpose According to previous Nordic Arthroplasty Register Association (NARA) data, the 10-year implant survival of cemented total hip arthroplasties (THAs) is 94% in patients aged 65–74 and 96% in patients aged 75 or more. Here we report a brand-level comparison of cemented THA based on the NARA database, which has not been done previously. Patients and methods We determined the rate of implant survival of the 9 most common cemented THAs in the NARA database. We used Kaplan-Meier analysis with 95% CI to study implant survival at 10 and 15 years, and Cox multiple regression to assess survival and hazard ratios (HRs), with revision for any reason as endpoint and with adjustment for age, sex, diagnosis, and femoral head material. Results Spectron EF THA (89.9% (CI: 89.3–90.5)) and Elite THA (89.8% (CI: 89.0–90.6)) had the lowest 10-year survivorship. Lubinus (95.7% survival, CI: 95.5–95.9), MS 30 (96.6%, CI: 95.8–97.4), and C-stem THA (95.8%, CI: 94.8–96.8) had a 10-year survivorship of at least 95%. Lubinus (revision risk (RR) = 0.77, CI: 0.73–0.81), Müller (RR =0.83, CI: 0.70–0.99), MS-30 (RR =0.73, CI: 0.63–0.86), C-stem (RR =0.70, CI: 0.55–0.90), and Exeter Duration THA (RR =0.84, CI: 0.77–0.90) had a lower risk of revision than Charnley THA, the reference implant. Interpretation The Spectron EF THA and the Elite THA had a lower implant survival than the Charnley, Exeter, and Lubinus THAs. Implant survival of the Müller, MS 30, CPT, and C-stem THAs was above the acceptable limit for 10-year survival. PMID:27550058

  11. Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material

    PubMed Central

    2010-01-01

    Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous

  12. Modular titanium alloy neck adapter failures in hip replacement--failure mode analysis and influence of implant material.

    PubMed

    Grupp, Thomas M; Weik, Thomas; Bloemer, Wilhelm; Knaebel, Hanns-Peter

    2010-01-04

    Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery.The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130 degrees and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurRence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous abrasion and

  13. Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.

    PubMed

    Winkler, Heinz

    2009-09-04

    Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its

  14. Metal artifact reduction (MAR) based on two-compartment physical modeling: evaluation in patients with hip implants.

    PubMed

    Boos, Johannes; Sawicki, Lino Morris; Lanzman, Rotem Shlomo; Thomas, Christoph; Aissa, Joel; Schleich, Christoph; Heusch, Philipp; Antoch, Gerald; Kröpil, Patric

    2017-01-01

    Artifacts from metallic implants can hinder image interpretation in computed tomography (CT). Image quality can be improved using metal artifact reduction (MAR) techniques. To evaluate the impact of a MAR algorithm on image quality of CT examinations in comparison to filtered back projection (FBP) in patients with hip prostheses. Twenty-two patients with 25 hip prostheses who underwent clinical abdominopelvic CT on a 64-row CT were included in this retrospective study. Axial images were reconstructed with FBP and five increasing MAR levels (M30-34). Objective artifact strength (OAS) (SIart-SInorm) was assessed by region of interest (ROI) measurements in position of the strongest artifact (SIart) and in an osseous structure without artifact (SInorm) (in Hounsfield units [HU]). Two independent readers evaluated subjective image quality regarding metallic hardware, delineation of bone, adjacent muscle, and pelvic organs on a 5-point scale (1, non-diagnostic; 5, excellent image quality). Artifacts in the near field, far field, and newly induced artifacts due to the MAR technique were analyzed. OAS values were: M34: 243.8 ± 155.4 HU; M33: 294.3 ± 197.8 HU; M32: 340.5 ± 210.1 HU; M31: 393.6 ± 225.2 HU; M30: 446.8 ± 224.2 HU and FBP: 528.9 ± 227.7 HU. OAS values were significantly lower for M32-34 compared to FBP (P < 0.01). For overall subjective image quality, results were: FBP, 2.0 ± 0.2; M30, 2.3 ± 0.8; M31, 2.6 ± 0.5; M32, 3.0 ± 0.6; M33, 3.5 ± 0.6; and M34, 3.8 ± 0.4 (P < 0.001 for M30-M34 vs. FBP, respectively). Increasing MAR levels resulted in new artifacts in 17% of reconstructions. The investigated MAR algorithm led to a significant reduction of artifacts from metallic hip implants. The highest MAR level provided the least severe artifacts and the best overall image quality. © The Foundation Acta Radiologica 2016.

  15. Design and optimization of the oriented groove on the hip implant surface to promote bone microstructure integrity.

    PubMed

    Noyama, Yoshihiro; Nakano, Takayoshi; Ishimoto, Takuya; Sakai, Takashi; Yoshikawa, Hideki

    2013-02-01

    We proposed a novel surface modification for an artificial hip joint stem from the viewpoint of maintenance and establishment of appropriate bone function and microstructure, represented by the preferred alignment of biological apatite (BAp) and collagen (Col). Oriented grooves were introduced into the proximal medial region of the femoral stem to control the principal stress applied to the bone inside the grooves, which is a dominant factor contributing to the promotion of Col/BAp alignment. The groove angle and the stem material were optimized based on the stress inside the grooves through a finite element analysis (FEA). Only the groove oriented proximally by 60° from the normal direction of the stem surface generated the healthy maximum principal stress distribution. The magnitude of the maximum principal stress inside the groove decreased with increasing the stem Young's modulus, while the direction of the stress did not largely changed. An in vivo implantation experiment showed that this groove was effective in inducing the new bone with preferential Col/BAp alignment along the groove depth direction which corresponded to the direction of maximum principal stress inside the groove. The anisotropic principal stress distribution and the oriented microstructure inside the groove are similar to those found in the femoral trabeculae; therefore, the creation of the oriented groove is a potent surface modification for optimizing implant design for a long-term fixation.

  16. Evidence for the dissolution of molybdenum during tribocorrosion of CoCrMo hip implants in the presence of serum protein.

    PubMed

    Simoes, Thiago A; Bryant, Michael G; Brown, Andy P; Milne, Steven J; Ryan, Mary; Neville, Anne; Brydson, Rik

    2016-11-01

    We have characterized CoCrMo, Metal-on-Metal (MoM) implant, wear debris particles and their dissolution following cycling in a hip simulator, and have related the results to the tribocorrosion of synthetic wear debris produced by milling CoCrMo powders in solutions representative of environments in the human body. Importantly, we have employed a modified ICP-MS sample preparation procedure to measure the release of ions from CoCrMo alloys during wear simulation in different media; this involved use of nano-porous ultrafilters which allowed complete separation of particles from free ions and complexes in solution. As a result, we present a new perspective on the release of metal ions and formation of metal complexes from CoCrMo implants. The new methodology enables the mass balance of ions relative to complexes and particles during tribocorrosion in hip simulators to be determined. A much higher release of molybdenum ions relative to cobalt and chromium has been measured. The molybdenum dissolution was enhanced by the presence of bovine serum albumin (BSA), possibly due to the formation of metal-protein complexes. Overall, we believe that the results could have significant implications for the analysis and interpretation of metal ion levels in fluids extracted from hip arthroplasty patients; we suggest that metal levels, including molybdenum, be analysed in these fluids using the protocol described here. We have developed an important new protocol for the analysis of metal ion levels in fluids extracted from hip implant patients and also hip simulators. Using this procedure, we present a new perspective on the release of metal ions from CoCrMo alloy implants, revealing significantly lower levels of metal ion release during tribocorrosion in hip simulators than previously thought, combined with the release of much higher percentages of molybdenum ions relative to cobalt and chromium. This work is of relevance, both from the perspective of the fundamental science and

  17. Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

    PubMed

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted Mo

  18. A Randomised Multi-centre Study to Compare the Long-term Performance of the Future Hip to 3 Other Implants in Primary Total Hip Replacement

    ClinicalTrials.gov

    2016-10-06

    Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis; Perthes Disease

  19. Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies

    PubMed Central

    Nieuwenhuijse, Marc J; Nelissen, R G H H; Schoones, J W

    2014-01-01

    Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. Results After assessment of 10 557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15 384 implants in 13 164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes

  20. Long-term effectiveness of an ad hoc tailored titanium implant as a spacer for microvascular decompression in the treatment of trigeminal neuralgia caused by megadolichoectatic basilar artery anomaly: 9-year follow-up.

    PubMed

    Banczerowski, Péter; Czigléczki, Gábor; Nyáry, István

    2014-12-01

    An enlarged, elongated, ectatic, and sclerotic aberration of the vertebrobasilar system is known as a megadolichoectatic basilar artery (BA) anomaly. The anomaly is often involved in the pathological process of trigeminal neuralgia by compressing and distorting the trigeminal nerve. First-line medical treatment includes drug therapy, but a second-line surgical procedure could be effective in medication-resistant cases. The authors report the case of a 65-year-old man with a 12-year history of progressing trigeminal neuralgia who underwent microvascular decompression after the first-line drug treatment had failed. This case is unique because an in situ tailored titanium microplate was used as a spacer to alleviate compression by the BA on the trigeminal nerve. The titanium implant provided durable and sufficient retraction for the sclerotic arterial complex when the trigeminal nerve was placed in the tunnel of the implant. The 9-year follow-up examination proves the safety and long-term efficacy of titanium implants in the treatment of trigeminal neuralgia caused by a megadolichoectatic BA anomaly. The method applied in this case was not intended to be and certainly is not an alternative to routine microvascular decompression-this surgical solution may be reserved for some extreme cases.

  1. Full-field in vitro measurements and in silico predictions of strain shielding in the implanted femur after total hip arthroplasty.

    PubMed

    Chanda, Souptick; Dickinson, Alexander; Gupta, Sanjay; Browne, Martin

    2015-08-01

    Alterations in bone strain as a result of implantation may contribute towards periprosthetic bone density changes after total hip arthroplasty. Computational models provide full-field strain predictions in implant-bone constructs; however, these predictions should be verified using experimental models wherever it is possible. In this work, finite element predictions of surface strains in intact and implanted composite femurs were verified using digital image correlation. Relationships were sought between post-implantation strain states across seven defined Gruen zones and clinically observed longer-term bone density changes. Computational predictions of strain distributions in intact and implanted femurs were compared to digital image correlation measurements in two regions of interest. Regression analyses indicated a strong linear correlation between measurements and predictions (R = 0.927 intact, 0.926 implanted) with low standard error (standard error = 38 µε intact, 26 µε implanted). Pre- to post-operative changes in measured and predicted surface strains were found to relate qualitatively to clinically observed volumetric bone density changes across seven Gruen zones: marked proximal bone density loss corresponded with a 50%-64% drop in surface strain, and slight distal density changes corresponded with 4%-14% strain increase. These results support the use of digital image correlation as a pre-clinical tool for predicting post-implantation strain shielding, indicative of long-term bone adaptations. © IMechE 2015.

  2. Treatment of acetabular fractures in older patients-introduction of a new implant for primary total hip arthroplasty.

    PubMed

    Resch, H; Krappinger, D; Moroder, P; Auffarth, A; Blauth, M; Becker, J

    2017-04-01

    Fractures of the acetabulum in younger patients are commonly treated by open reduction and internal fixation. For elderly patients, stable primary total hip arthroplasty with the advantage of immediate postoperative mobilization might be the adequate treatment. For this purpose, a sufficiently stable fixation of the acetabular component is required. Between August 2009 and 2014, 30 cases were reported in which all patients underwent total hip arthroplasty additionally to a customized implant designed as an antiprotrusion cage. Inclusion criteria were an acetabular fracture with or without a previous hemiarthroplasty, age above 65 years, and pre-injury mobility dependent on a walking frame at the most. The median age was 79.9 years (65-92), and of 30 fractures, 25 were primary acetabular fractures (83%), four periprosthetic acetabular fractures (14%), and one non-union after a failed ORIF (3%). The average time from injury to surgery was 9.4 days (3-23) and 295 days for the non-union case. Mean time of surgery was 154.4 min (range 100 to 303). In 21 cases (70%), mobilization with full weight bearing was possible within the first 10 days. Six patients died before the follow-up examination 3 and 6 months after surgery, while 24 patients underwent radiologic examination showing consolidated fractures in bi-plane radiographs. In 9 patients, additional CT scan was performed which confirmed the radiographical results. 13 had regained their pre-injury level of mobility including the non-union case. Only one patient did not regain independent mobility. Four complications were recognized with necessary surgical revision (one prosthetic head dislocation, one pelvic cement leakage, one femoral shaft fracture, and one infected hematoma). The presented cage provides the possibility of early mobilization with full weight bearing which represents a valuable addition to the treatment spectrum in this challenging patient group.

  3. Intra-operative evaluation of cementless hip implant stability: a prototype device based on vibration analysis.

    PubMed

    Lannocca, Maurizio; Varini, Elena; Cappello, Angelo; Cristofolini, Luca; Bialoblocka, Ewa

    2007-10-01

    Cementless implants are mechanically stabilized during surgery by a press-fitting procedure. Good initial stability is crucial to avoid stem loosening and bone cracking, therefore, the surgeon must achieve optimal press-fitting. A possible approach to solve this problem and assist the surgeon in achieving the optimal compromise, involves the use of vibration analysis. The present study aimed to design and test a prototype device able to evaluate the primary mechanical stability of a cementless prosthesis, based on vibration analysis. In particular, the goal was to discriminate between stable and quasi-stable implants; thus the stem-bone system was assumed to be linear in both cases. For that reason, it was decided to study the frequency responses of the system, instead of the harmonic distortion. The prototype developed consists of a piezoelectric exciter connected to the stem and an accelerometer attached to the femur. Preliminary tests were performed on four composite femurs implanted with a conventional stem. The results showed that the input signal was repeatable and the output could be recorded accurately. The most sensitive parameter to stability was the shift in resonance frequency of the stem-bone system, which was highly correlated with residual micromotion on all four specimens.

  4. Influence of the clearance on in-vitro tribology of large diameter metal-on-metal articulations pertaining to resurfacing hip implants.

    PubMed

    Rieker, Claude B; Schön, Rolf; Konrad, Reto; Liebentritt, Gernot; Gnepf, Patric; Shen, Ming; Roberts, Paul; Grigoris, Peter

    2005-04-01

    Large-diameter metal-on-metal articulations may provide an opportunity for wear reduction in total hip implants because earlier studies have shown that the formation of a fluid film that completely separates the bearing surfaces is theoretically possible. In such a lubrication mode and under ideal conditions, there is theoretically no amount of wear. Studies have suggested that the two primary parameters controlling the lubrication mode are the diameter and the clearance of the articulation. The goal of the present study was to experimentally investigate the influence of these two parameters on the wear behavior of large-diameter metal-on-metal articulations pertaining to resurfacing hip implants. The results of this in vitro investigation showed that longer running-in periods and higher amounts of running-in wear were associated with larger clearances.

  5. Effects of CoCr metal wear debris generated from metal-on-metal hip implants and Co ions on human monocyte-like U937 cells.

    PubMed

    Posada, Olga M; Tate, Rothwelle J; Grant, M Helen

    2015-03-01

    Hip resurfacing with cobalt-chromium (CoCr) alloy was developed as a surgical alternative to total hip replacement. However, the biological effects of nanoparticles generated by wear at the metal-on-metal articulating surfaces has limited the success of such implants. The aim of this study was to investigate the effects of the combined exposure to CoCr nanoparticles and cobalt ions released from a resurfacing implant on monocytes (U937 cells) and whether these resulted in morphology changes, proliferation alterations, toxicity and cytokine release. The interaction between prior exposure to Co ions and the cellular response to nanoparticulate debris was determined to simulate the situation in patients with metal-on-metal implants receiving a second implant. Effects on U937 cells were mainly seen after 120h of treatment. Prior exposure to Co ions increased the toxic effects induced by the debris, and by Co ions themselves, suggesting the potential for interaction in vivo. Increased TNF-α secretion by resting cells exposed to nanoparticles could contribute to osteolysis processes in vivo, while increased IFN-γ production by activated cells could represent cellular protection against tissue damage. Data suggest that interactions between Co ions and CoCr nanoparticles would occur in vivo, and could threaten the survival of a CoCr metal implant. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Transient elastohydrodynamic lubrication analysis of metal-on-metal hip implant under simulated walking conditions.

    PubMed

    Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P

    2006-01-01

    The transient elastohydrodynamic lubrication (EHL) analysis was performed in this study for a typical metal-on-metal bearing employing a polyethylene backing underneath a metallic cup inlay under dynamic operating conditions of load and speed representative of normal walking. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup. The governing Reynolds and elasticity equations were solved simultaneously by using both finite difference and finite element methods. The predicted transient film thickness from the present study was compared with the estimation based on the quasi-static analysis. It was found that the polyethylene backing employed in the typical metal-on-metal hip bearing, combined with dynamic squeeze-film action, significantly improved the transient lubricant film thickness under cyclic walking and consequently a fluid film lubrication regime was possible for smooth bearing surfaces with an average roughness less than 0.005 microm.

  7. Long-term Bisphosphonate Therapy-induced Periprosthetic Femoral Stress Fracture in a Sliding Hip Screw Implant: A Unique Case Report

    PubMed Central

    Adams, Mark R; Dunn, Conor; Sirkin, Michael S; Reilly, Mark C

    2016-01-01

    Introduction: Long-term bisphosphonate therapy for osteoporosis is associated with an increased risk of low-to-no energy atypical subtrochanteric and femoral shaft fractures with characteristic radiologic findings. There are few reports of patients with long-term bisphosphonate-induced periprosthetic fractures, all of them had a hip arthroplasty prosthesis. In this report, we present a unique case of a 90-year-old Caucasian female on long-term bisphosphonate therapy with a sliding hip screw implant who sustained a periprosthetic fracture of the femoral shaft at the distal aspect of the plate. Case Report: In April 2014, a 90-year-old female presented with left thigh pain after a fall from standing height. She had a previous fixation of a left intertrochanteric hip fracture with a sliding hip screw in 1999 and a 9-year history of bisphosphonate therapy. Radiographs obtained in the emergency department revealed a left-sided femoral shaft fracture at the distal aspect of the previously applied five-hole side plate. Of note, the periprosthetic fracture demonstrated cortical thickening at the fracture site of the lateral femoral cortex, lack of comminution as well as a transverse appearance. The patient was taken to the operating room the next day for retrograde placement of an intramedullary nail of the left femur with revision of left intertrochanteric femur fracture fixation. By 3 months postoperatively, she had obtained full radiographic union. Conclusion: This case report highlights the possibility of an atypical fracture distal to the sliding hip screw implant after open reduction internal fixation of an intertrochanteric hip fracture in patients on long-term bisphosphonates. PMID:28164053

  8. The Effect of Impact Location on Force Transmission to the Modular Junctions of Dual-Taper Modular Hip Implants.

    PubMed

    Frisch, Nicholas B; Lynch, Jonathan R; Banglmaier, Richard F; Silverton, Craig D

    2016-09-01

    The purpose of this study was to investigate the effect that off-axis impaction has on stability of dual-taper modular implants as measured by forces delivered to and transmitted through the head-neck and neck-stem tapers, respectively. One hundred forty-four impact tests were performed using 6 different directions: one on-axis and five 10° off-axes. Four different simulations were performed measuring the head-neck only and 3 different neck angulations: 0°, 8°, and 15°. A drop tower impactor delivered both on- and off-axis impaction from a constant height. Load cells positioned in the drop mass and at the head-neck (HN) or neck-stem (NS) junction measured the impact and joint forces, respectively. Impact force of the hammer on the head ranged from 3800-4500 N. Greatest impact force delivered to the head was typically with axial impact. However, greatest force transmission to the neck-stem junction was not necessarily with axial impacts. There was limited variability in the force measured at the NS junction for all impaction directions seen in the 8° neck, whereas the 15° neck had greater forces transmitted to the NS junction with off-axes impactions directed in the proximal and posterior-proximal directions. The location of the impact significantly influences the force transmitted to the head-neck and neck-stem junctions in dual-taper modular hip implants. Although axial impacts proved superior to off-axis impacts for the straight 0° neck, greater force transmission with off-axis impacts for the angled necks suggests that off-axis impacts may potentially compromise the stability of dual-taper components. Published by Elsevier Inc.

  9. [Thoughts on the use of mechatronic implantation aids in minimal approaches in hip prostheses].

    PubMed

    Wahrburg, J; Kerschbaumer, F

    2000-07-01

    A new concept of THR surgery is presented: A combination of limited surgical approach, intraoperative digitizing, and use of a semi-active robot shows the important advantage of easy registration, reproducible positioning of surgical instruments, and less invasive surgery. Using this system originally designed for accurate socket implantation, it will be possible to perform total THR in the future. For preoperative planning, we are currently investigating the use of biplanar digital radiographics with transformation into a 3D-model in order to avoid CT scans in the pelvic area.

  10. Advanced metal artifact reduction MRI of metal-on-metal hip resurfacing arthroplasty implants: compressed sensing acceleration enables the time-neutral use of SEMAC.

    PubMed

    Fritz, Jan; Fritz, Benjamin; Thawait, Gaurav K; Raithel, Esther; Gilson, Wesley D; Nittka, Mathias; Mont, Michael A

    2016-10-01

    Compressed sensing (CS) acceleration has been theorized for slice encoding for metal artifact correction (SEMAC), but has not been shown to be feasible. Therefore, we tested the hypothesis that CS-SEMAC is feasible for MRI of metal-on-metal hip resurfacing implants. Following prospective institutional review board approval, 22 subjects with metal-on-metal hip resurfacing implants underwent 1.5 T MRI. We compared CS-SEMAC prototype, high-bandwidth TSE, and SEMAC sequences with acquisition times of 4-5, 4-5 and 10-12 min, respectively. Outcome measures included bone-implant interfaces, image quality, periprosthetic structures, artifact size, and signal- and contrast-to-noise ratios (SNR and CNR). Using Friedman, repeated measures analysis of variances, and Cohen's weighted kappa tests, Bonferroni-corrected p-values of 0.005 and less were considered statistically significant. There was no statistical difference of outcomes measures of SEMAC and CS-SEMAC images. Visibility of implant-bone interfaces and pseudocapsule as well as fat suppression and metal reduction were "adequate" to "good" on CS-SEMAC and "non-diagnostic" to "adequate" on high-BW TSE (p < 0.001, respectively). SEMAC and CS-SEMAC showed mild blur and ripple artifacts. The metal artifact size was 63 % larger for high-BW TSE as compared to SEMAC and CS-SEMAC (p < 0.0001, respectively). CNRs were sufficiently high and statistically similar, with the exception of CNR of fluid and muscle and CNR of fluid and tendon, which were higher on intermediate-weighted high-BW TSE (p < 0.005, respectively). Compressed sensing acceleration enables the time-neutral use of SEMAC for MRI of metal-on-metal hip resurfacing implants when compared to high-BW TSE and image quality similar to conventional SEMAC.

  11. The Chemical Form of Metal Species Released from Corroded Taper Junctions of Hip Implants: Synchrotron Analysis of Patient Tissue.

    PubMed

    Di Laura, Anna; Quinn, Paul D; Panagiotopoulou, Vasiliki C; Hothi, Harry S; Henckel, Johann; Powell, Jonathan J; Berisha, Fitim; Amary, Fernanda; Mosselmans, J Fred W; Skinner, John A; Hart, Alister J

    2017-09-08

    The mechanisms of metal release from the articulation at the head cup bearing and the tapered junctions of orthopaedic hip implants are known to differ and the debris generated varies in size, shape and volume. Significantly less metal is lost from the taper junction between Cobalt-Chromium-Molybdenum (CoCrMo) and Titanium (Ti) components (fretting-corrosion dominant mechanism), when compared to the CoCrMo bearing surfaces (wear-corrosion dominant mechanism). Corrosion particles from the taper junction can lead to Adverse Reactions to Metal Debris (ARMD) similar to those seen with CoCrMo bearings. We used synchrotron methods to understand the modes underlying clinically significant tissue reactions to Co, Cr and Ti by analysing viable peri-prosthetic tissue. Cr was present as Cr2O3 in the corroded group in addition to CrPO4 found in the metal-on-metal (MoM) group. Interestingly, Ti was present as TiO2 in an amorphous rather than rutile or anatase physical form. The metal species were co-localized in the same micron-scale particles as result of corrosion processes and in one cell type, the phagocytes. This work gives new insights into the degradation products from metal devices as well as guidance for toxicological studies in humans.

  12. The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.

    PubMed

    Varano, R; Bobyn, J D; Medley, J B; Yue, S

    2006-02-01

    The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism.

  13. Treatment of periprosthetic acetabular fractures after previous hemi- or total hip arthroplasty: Introduction of a new implant.

    PubMed

    Resch, H; Krappinger, D; Moroder, P; Blauth, M; Becker, J

    2016-04-01

    Treatment of displaced periprosthetic acetabular fractures in elderly patients. The goal is to stabilize an acetabular fracture independent of the fracture pattern, by inserting the custom-made roof-reinforcement plate and starting early postoperative full weight-bearing mobilization. Acetabular fracture with or without previous hemi- or total hip arthroplasty. Non-displaced acetabular fractures. Watson-Jones approach to provide accessibility to the anterior and supraacetabular part of the iliac bone. Angle-stable positioning of the roof-reinforcement plate without any fracture reduction. Cementing a polyethylene cup into the metal plate and restoring prosthetic femoral components. Full weight-bearing mobilization within the first 10 days after surgery. In cases of two column fractures, partial weight-bearing is recommended. Of 7 patients with periprosthetic acetabular fracture, 5 were available for follow-up at 3, 6, 6, 15, and 24 months postoperatively. No complications were recognized and all fractures showed bony consolidation. Early postoperative mobilization was started within the first 10 days. All patients except one reached their preinjury mobility level. This individual and novel implant is custom made for displaced acetabular and periprosthetic fractures in patients with osteopenic bone. It provides a hopeful benefit due to early full weight-bearing mobilization within the first 10 days after surgery. In case of largely destroyed supraacetabular bone or two-column fractures according to Letournel additional synthesis via an anterior approach might be necessary. In these cases partial weight bearing is recommended.

  14. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint (hemi-hip) acetabular metal cemented... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip...

  15. Pore Geometry Optimization of Titanium (Ti6Al4V) Alloy, for Its Application in the Fabrication of Customized Hip Implants

    PubMed Central

    Roy, Sandipan; Panda, Debojyoti; Khutia, Niloy; Chowdhury, Amit Roy

    2014-01-01

    The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected to in vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits. PMID:25400663

  16. Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study

    PubMed Central

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation. PMID:25247185

  17. Survivorship of Hip and Knee Implants in Pediatric and Young Adult Populations

    PubMed Central

    Sedrakyan, Art; Romero, Lucas; Graves, Stephen; Davidson, David; de Steiger, Richard; Lewis, Peter; Solomon, Michael; Vial, Robyn; Lorimer, Michelle

    2014-01-01

    Background: One of the least researched areas in orthopaedic pediatrics is the safety and effectiveness of joint replacement, in part because it is uncommon and is undertaken for a wide range of conditions not common for adult joint replacement. This study used data from the AOANJRR (Australian Orthopaedic Association National Joint Replacement Registry) to analyze the use of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the pediatric population and to provide preliminary data on the outcome of these procedures. Methods: The AOANJRR, which is part of the ICOR (International Consortium of Orthopaedic Registries), provided information on pediatric procedures reported to the registry by hospitals undertaking arthroplasty procedures in Australia. All THA and TKA procedures reported to the registry from 1999 to 2012 were included. The cumulative percent revision and the hazard ratio from Cox proportional-hazards models were used for analysis. All tests were two-tailed, with a 5% level of significance. Additionally, an overview of the literature is presented to provide a point of reference. Results: Primary conventional THA was performed in 297 patients twenty years of age or younger; the cumulative percent revision at five years was 4.5%. Primary conventional THA was performed in 975 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 5.4%. Primary THA was performed in 105 patients twenty years of age or younger; the cumulative percent revision at five years was 4.6%. Primary TKA was performed in 159 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 10.3%. Conclusions: Compared with older adults, pediatric patients and young adults undergoing THA and TKA have very different diagnoses, including a high prevalence of tumor. Although the reported rate of revision surgery is currently similar to that for older patients, the number of reported procedures and the

  18. Management of Periprosthetic Hip Joint Infection

    PubMed Central

    Lee, Hee Dong; Prashant, Kumar

    2015-01-01

    Total hip joint replacement offers dramatic improvement in the quality of life but periprosthetic joint infection (PJI) is the most devastating complication of this procedure. The infection threatens the function of the joint, the preservation of the limb, and occasionally even the life of the patient due to long term hospitalization and high cost. For the surgeon it is a disastrous burden, which requires repeated, complicated procedures to eradicate infection and to provide a mobile joint without pain. Yet in the absence of a true gold standard, the diagnosis of PJI can be elusive. Synovial fluid aspiration, diagnostic imaging, traditional culture, peripheral serum inflammatory markers, and intraoperative frozen sections each have their limitations but continue to be the mainstay for diagnosis of PJI. Treatment options mainly include thorough irrigation and debridement with prosthesis retention, or a two-stage prosthesis exchange with intervening placement of an antibiotic-loaded spacer. Success in treating PJI depends on extensive surgical debridement and adequate and effective antibiotic therapy. Treatment in two stages using a spacer is recommended for most chronic PJI. Debridement, antibiotics and implant retention is the obvious choice for treatment of acute PJI, with good success rates in selected patients. This article presents an overview of recent management concepts for PJI of the hip emphasizing diagnosis and the clinical approach, and also share own experience at our institution. PMID:27536605

  19. Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

    PubMed Central

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip

  20. The accuracy of Acuros XB algorithm for radiation beams traversing a metallic hip implant - comparison with measurements and Monte Carlo calculations.

    PubMed

    Ojala, Jarkko; Kapanen, Mika; Sipilä, Petri; Hyödynmaa, Simo; Pitkänen, Maunu

    2014-09-08

    In this study, the clinical benefit of the improved accuracy of the Acuros XB (AXB) algorithm, implemented in a commercial radiotherapy treatment planning system (TPS), Varian Eclipse, was demonstrated with beams traversing a high-Z material. This is also the first study assessing the accuracy of the AXB algorithm applying volumetric modulated arc therapy (VMAT) technique compared to full Monte Carlo (MC) simulations. In the first phase the AXB algorithm was benchmarked against point dosimetry, film dosimetry, and full MC calculation in a water-filled anthropometric phantom with a unilateral hip implant. Also the validity of the full MC calculation used as reference method was demonstrated. The dose calculations were performed both in original computed tomography (CT) dataset, which included artifacts, and in corrected CT dataset, where constant Hounsfield unit (HU) value assignment for all the materials was made. In the second phase, a clinical treatment plan was prepared for a prostate cancer patient with a unilateral hip implant. The plan applied a hybrid VMAT technique that included partial arcs that avoided passing through the implant and static beams traversing the implant. Ultimately, the AXB-calculated dose distribution was compared to the recalculation by the full MC simulation to assess the accuracy of the AXB algorithm in clinical setting. A recalculation with the anisotropic analytical algorithm (AAA) was also performed to quantify the benefit of the improved dose calculation accuracy of type 'c' algorithm (AXB) over type 'b' algorithm (AAA). The agreement between the AXB algorithm and the full MC model was very good inside and in the vicinity of the implant and elsewhere, which verifies the accuracy of the AXB algorithm for patient plans with beams traversing through high-Z material, whereas the AAA produced larger discrepancies.

  1. Good vs Poor Results After Total Hip Arthroplasty: An Analysis Method Using Implant and Anatomic Parameters With the EOS Imaging System.

    PubMed

    Bendaya, Samy; Anglin, Carolyn; Lazennec, Jean-Yves; Allena, Rachele; Thoumie, Philippe; Skalli, Wafa

    2016-09-01

    Existing imaging techniques and single-parameter analyses, in nonfunctional positions, fail to detect the differences between patients with good vs poor results after total hip arthroplasty. The present study developed an analysis method using the EOS full-body, low-dose, biplanar, weightbearing imaging system to compare good vs poor patients after total hip arthroplasty and to report on our preliminary experiences (17 good, 18 poor). All revision cases were found to have at least 4 high or low implant or anatomic parameters relative to the good group. These included acetabular cup orientation, sagittal pelvic tilt, sacral slope, femoral offset, and neck-shaft angle. Acetabular cup orientation differed significantly between groups. With the EOS system, a large cohort can be studied relatively quickly and at low dose, which could lead to patient-specific guidelines. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Bone remodeling after total hip arthroplasty with a short stemmed metaphyseal loading implant: finite element analysis validated by a prospective DEXA investigation.

    PubMed

    Lerch, Matthias; Kurtz, Agnes; Stukenborg-Colsman, Christina; Nolte, Ingo; Weigel, Nelly; Bouguecha, Anas; Behrens, Bernd A

    2012-11-01

    In total hip arthroplasty (THA), short stemmed cementless implants are used because they are thought to stimulate physiological bone remodeling and reduce stress shielding. We performed a numerical investigation on bone remodeling after implantation of a specific short stemmed implant using finite element analysis (FEA). Overall bone mass loss was 2.8% in the entire femur. Bone mass decrease was mostly found in the proximal part of the calcar and in the greater trochanter due to the vast cross section of the implant, probably leading to stress shielding. In the diaphysis, no change in the apparent bone density was proven. The assumptions made agreed well with bone remodeling data from THA recipients who underwent dual-energy X-ray absorptiometry. However, the clinical investigation revealed a bone mass increase in the minor trochanter region that was less pronounced in the FEA. Further comparisons to other stem designs must be done to verify if the relative advantages of the investigated implant can be accepted.

  3. [The use of a thermomechanical cleaning procedure for removal of residual particles of corund blasted or glass bead peened implants in total hip arthoplasty].

    PubMed

    Schuh, A; Uter, W; Holzwarth, U; Kachler, W; Göske, J; Müller, T

    2005-08-01

    Shot peening and grit blasting techniques are used to modify surfaces of hip endoprostheses. Alumina blasting techniques using highly pure corund (Al (2)O (3)) particles create a rough surface of Titanium implants to achieve a better osteointegration in cementless total hip arthroplasty. An increasing number of publications in maxillo-facial-surgery and orthopedic surgery show that there is a significant contamination with remnants on corund blasted surfaces. To our knowledge no previous study analysed the effects of cleaning procedures of hip endoprostheses in respect to glass beads and Al (2)O (3) remnants. The surface of the flexible anisotropic Vector cup and the stiff modular MRP-Titan stem (one implant each) were analysed with respect to Al (2)O (3) or glass particles before and after the cleaning procedure. The implants were cleaned using an ultrasound bath for 10 or 20 minutes under nitrogen cooling or simple ultrasound bath with water. A field emission scanning electron microscopy (LEO 1525) was used for the detection of the particles on the implant surface with a backscattered electron detector. The proportion of the surface covered with particles was determined with an imaging analyze software (analySIS, Soft Imaging System GmbH). A reduction of corund particles on the surface of the flexible anisotropic Vector cup of up to 5.2 % (from 40.0 % to 34.8 %) after 10 minutes nitrogen cooling was achieved. A reduction of corund particles on the surface of the stiff MRP-Titan stem of up to 2.2 % (from 38.8 % to 36.6 %) was observed after 20 minutes of non cooled ultrasound bath whereas a reduction up to 3.2 % (from 25.8 % to 22.6 %) of glass particles after 10 minutes of nitrogen cooled ultrasound bath was detected. With the cleaning procedure tested only incomplete removal of just the small glass and Al (2)O (3) particles is possible. Further research is needed to reduce or even avoid residual particles in total hip arthoplasty.

  4. Radiographic identification of loose bodies in the traumatized hip joint

    SciTech Connect

    Baird, R.A.; Schobert, W.E.; Pais, M.J.; Ahmed, M.; Wilson, W.J.; Farjalla, G.L.; Imray, T.J.

    1982-12-01

    Acrylic spacers and cubes of cortical bone of known dimensions were placed in predetermined locations in cadaver hip joints, which were then studied with plain radiography and linear, hypocycloidal, and computed tomography (CT). Joint space widening was not measurable on plain radiographs of the pelvis when 2-mm spacers were placed anywhere within the hip joint. When 4-mm spacers were used, widening measured 2 mm in the axis of measurement corresponding to the location of the spacer. Linear tomography did not permit identification of the 2-mm cubes; however, hypocycloidal tomography and CT consistently showed them anywhere within the hip joint. Radiation dose and clinical recommendations are discussed.

  5. Hip pain

    MedlinePlus

    ... pain involves any pain in or around the hip joint. You may not feel pain from your hip ... 2012:chap 48. Read More Hip fracture surgery Hip joint replacement Patient Instructions Hip fracture - discharge Hip or ...

  6. [Conduct and tactics of infections after hip arthroplasty].

    PubMed

    Białecki, Jerzy; Marczyński, Wojciech; Milecki, Marcin; Obrebski, Marcin; Szyszka, Michał

    2009-01-01

    The number of arthroplasty surgeries is growing globally, bringing about an increase in the absolute number of infected complications. No precise statistics of complications are available in Poland. The present paper discusses the main causes of infected complications of hip arthroplasty. The object is to present both pre-surgery prophylaxis and the treatment of an infected complication adjacent to the endoprosthesis. Infections are commonly divided after Coventry and Fitzgerald. The most common pathogens in infected endoprostheses include Staphylococcus aureus and Staphylococcus epidermidis, while the treatment of infections with the Gram-negative flora poses many problems. Discussed within treatment of infected complications of hip arthroplasty has been one- and two-stage surgical treatment with temporary implants--"spacers"--combines with prolonged antibiotic therapy. Important within the post-surgery treatment is prolonged monitoring of the infective agents (CRP and SR).

  7. Hip Microfracture

    PubMed Central

    McGill, Kevin C.; Bush-Joseph, Charles A.; Nho, Shane J.

    2010-01-01

    Microfracture is a marrow-stimulating technique used in the hip to treat cartilage defects associated with femoro-acetabular impingement, instability, or traumatic hip injury. These defects have a low probability of healing spontaneously and therefore often require surgical intervention. Originally adapted from the knee, microfracture is part of a spectrum of cartilage repair options that include palliative procedures such as debridement and lavage, reparative procedures such as marrow-stimulating techniques (abrasion arthroplasty and microfracture), and restorative procedures such as autologous chondrocyte implantation and osteochondral allograft/autografts. The basic indications for microfracture of the hip include focal and contained lesions typically less than 4 cm in diameter, full-thickness (Outerbridge grade IV) defects in weightbearing areas, unstable lesions with intact subchondral bone, and focal lesions without evidence of surrounding chondromalacia. Although not extensively studied in the hip, there are some small clinical series with promising early outcomes. Although the widespread use of microfracture in the hip is hindered by difficulties in identifying lesions on preoperative imaging and instrumentation to circumvent the femoral head, this technique continues to gain acceptance as an initial treatment for small, focal cartilage defects. PMID:26069544

  8. Toxicity of cobalt-chromium nanoparticles released from a resurfacing hip implant and cobalt ions on primary human lymphocytes in vitro.

    PubMed

    Posada, Olga M; Tate, R J; Grant, M H

    2015-06-01

    Adverse tissue responses to prostheses wear particles and released ions are important contributors to hip implant failure. In implant-related adverse reactions T-lymphocytes play a prominent role in sustaining the chronic inflammatory response. To further understand the involvement of lymphocytes in metal-on-metal (MoM) implant failure, primary human lymphocytes were isolated and treated with cobalt-chromium (Co-Cr) wear debris and Co ions, individually, and in combination, for 24, 48 and 120 h. There was a significant increase in cell number where debris was present, as measured by the Neutral Red assay. Interleukin-6 (IL-6), interferon-γ (IFN-γ) and tumour necrosis factor-α (TNF-α) secretion levels significantly decreased in the presence of metal particles, as measured by ELISA. Interleukin-2 (IL-2) secretion levels were significantly decreased by both debris and Co ions. Flow cytometry analysis showed that the metal nanoparticles induced a significant increase in apoptosis after 48-h exposure. This investigation showed that prolonged exposure (120 h) to metal debris induces lymphocyte proliferation, suggesting that activation of resting lymphocytes may have occurred. Although cytokine production was affected mainly by metal debris, cobalt toxicity may also modulate IL-2 secretion, and even Co ion concentrations below the MHRA guideline levels (7 ppb) may contribute to the impairment of immune regulation in vivo in patients with MoM implants.

  9. Influence of the fixation region of a press-fit hip endoprosthesis on the stress-strain state of the "bone-implant" system.

    PubMed

    Levadnyi, Ievgen; Awrejcewicz, Jan; Goethel, Márcio Fagundes; Loskutov, Alexander

    2017-05-01

    Although significant progress has been made in the development of total hip replacement, behaviour of the femoral component of an endoprosthesis in relation to the type of its fixation in the bone is still not fully understood. In this paper, behaviour of the femoral bone and the stem prosthesis is studied taking into account different types of prosthesis fixation in the medullary canal of the femur under the action of functional loads. For an analysis, a three-dimensional model of a femur has been developed based on the results of a computed tomography. The stress-strain state governing behaviour of the femoral bone and the stem prosthesis has been estimated with the use of the finite element method (FEM). The FEM analysis has shown that for the diaphyseal fixation, the area of contact between the surface of the endoprosthesis and the bone is insufficient and leads to large stresses in the implant accompanied by stress concentration in the distal femur. An increase in the area of contact between the implant and the bone raises the stiffness of the "bone-implant" system, which, in turn, reduces stresses in the implant. The applied metaphyseal-type fixation yielded an improvement of results regarding behaviour of the femoral bone and the stem prosthesis. Namely, the study yielded the distribution of stress in the bone similar to the physiological stress state. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Spacer-related problems in two-stage revision knee arthroplasty.

    PubMed

    Struelens, Bernard; Claes, Steven; Bellemans, Johan

    2013-08-01

    Although articulated cement spacers are frequently used in a staged approach of an infected total knee arthroplasty (TKA), no data are available on the incidence and type of spacer-related problems in these patients. A retrospective analysis of 154 patients who underwent a two-stage revision procedure for an infected TKA was performed. All patients received an articulating cement spacer at the implant removal procedure; their radiographs were analyzed for spacer-related issues such as spacer dislocation, fracture, tilting or translation, and knee subluxation. In 43% of the patients, the spacer was considered as optimal. The main finding of this study is the large incidence (57%) of spacer-specific problems in two-stage revision knee arthroplasty for infected TKA. Spacer tilting and mediolateral translation were found to be the most frequent spacer-specific problems, in 24% and 21% of the cases respectively. These were considered as minor problems. Major problems were seen in 12 % : in 3% of the knees the spacer had dislocated, in 5% the spacer fractured and in 4%, although the spacer seemed to be adequately positioned relative to the femoral and tibial bone, frank knee subluxation could be noted. The impact of spacer-specific problems with articulating cement spacers on final outcome in two-stage revision knee surgery will be further investigated.

  11. Short Versus Long Intramedullary Nails in the Treatment of Pertrochanteric Hip Fractures: Incidence of Ipsilateral Fractures and Costs Associated With Each Implant.

    PubMed

    Lindvall, Eric; Ghaffar, Samia; Martirosian, Armen; Husak, Lisa

    2016-03-01

    Both short intramedullary nails (SIMNs) and long intramedullary nails (LIMNs) are routinely used in the surgical treatment of pertrochanteric hip fractures. The purpose of this study was to assess the incidence of ipsilateral femur fractures after the surgical treatment of hip fractures and the overall costs associated with each implant. Retrospective cohort study. Level I trauma center and 2 community hospitals. A total of 609 patients with pertrochanteric hip fractures treated with an SIMN or LIMN from 2005 to 2011. Review of patient demographics and clinical outcomes over a 5-year follow-up period. Ipsilateral femur refracture rates were recorded for both groups, and a cost analysis was then performed to compare SIMNs and LIMNs while accounting for their observed refracture rates and surgical/hospital costs to determine the overall cost of each implant. Union rates were equivalent between groups and averaged over 97%. The incidence of ipsilateral femur fractures in both groups steadily increased with greater follow-up time to reach nearly 10% at 5 years. Although only 47% of all nails were locked distally, 15 of the 16 refractures occurred in nails that were not distally locked. Cost analysis revealed no significant difference in the use of short versus LIMNs over a 5-year period (P = 0.76). The incidence of ipsilateral femur refractures steadily rose with greater follow-up in both SIMN and LIMNs. Distally locking the initial fixation seems to protect against future femur fractures and may also affect the refracture location when using LIMNs. No differences in overall costs were seen at 1, 2, or 5 years between SIMNs and LIMNs. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  12. INNOPLANT Total Hip Replacement System.

    PubMed

    Harper, Tisha A M

    2017-07-01

    Total hip replacement is a salvage procedure that is done to alleviate discomfort secondary to osteoarthritis in the hip, which is most often a result of hip dysplasia. Commercially available total hip replacement implants for small animal patients are classified as cemented or cementless. The INNOPLANT Total Hip Replacement system includes modular, screw-in cementless components that were developed to improve implant stability by maintaining as much normal anatomic structure, and by extension biomechanics of the coxofemoral joint, as possible. As a newer system, there are few data and no long-term studies available in the veterinary literature. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Medpor lower eyelid spacer: does it biointegrate?

    PubMed

    Mavrikakis, Ioannis; Francis, Nick; Poitelea, Cornelia; Parkin, Ben; Brittain, Paul; Olver, Jane

    2009-01-01

    To report the histopathologic findings of explanted Medpor lower eyelid spacers (LES) in complicated cases. Four cases of lower eyelid retraction due to thyroid orbitopathy (n = 2), facial nerve palsy (n = 1), and post-enucleation socket syndrome (n = 1) were treated with Medpor LES. All implants were removed between 6 months to 2 years following their original insertion due to exposure, poor stability, or contour. Histopathology of the implants showed fibrosis and vascularization although clinically, at the time of removal, did not appear vascularized. In addition, immunohistochemistry was positive for Factor VIII related antigen and CD34, thus highlighting the presence of vessels in the pores and around the implant. To our knowledge, we are the first to report histopathologic findings of explanted high-density porous polyethylene implants from the lower eyelid in humans. Although this study shows that Medpor LES does biointegrate, we advocate using it sparingly due to associated complications such as exposure, poor stability, and contour.

  14. Retaining well-fixed cementless stem in the treatment of infected hip arthroplasty

    PubMed Central

    2013-01-01

    Background and purpose Two-stage reconstruction, reimplantation after removal of an infected prosthesis, has been considered to be the gold standard for treatment of infected hip arthroplasty. However, during the removal of a well-fixed femoral stem, the proximal femur can be damaged and a sequestrum can be formed, which might lead to chronic osteomyelitis and difficulty in reimplantation. We wanted to determine whether infection after hip arthroplasty can be treated without removal of a well-fixed stem. Methods We treated 19 patients who had an infection after hip replacement, but a well-fixed cementless stem, with 2-stage reconstruction. At the first stage, we removed the acetabular cup, the liner and the head, but not the stem. We then implanted a cup of cement spacer. After control of infection, we reimplanted the acetabular component and head. Results 2 patients did not undergo second-stage reconstruction because they were satisfied with the pain relief and the activity that they had with the cement-spacer implantation. The remaining 17 patients underwent the second-stage of the reconstruction using cementless arthroplasty. At a mean follow-up time of 4 (2–8) years, 15 of the patients had no recurrence of infection, with satisfactory clinical and radiographic outcome. Interpretation This second-stage reconstruction after retention of the stem could be an alternative treatment option for periprosthetic infection with a well-fixed stem. PMID:23621807

  15. [The primary stability between manual and robot assisted implantation of hip prostheses: A biomechanical study on synthetic femurs].

    PubMed

    Decking, J; Gerber, A; Kränzlein, J; Meurer, A; Böhm, B; Plitz, W

    2004-01-01

    We investigated the initial stability of cementless stems implanted with robotic milling and conventional manual broaching. Proximally porous structured stems (G2, ESKA-Implants, Luebeck, Germany) were implanted into synthetic femora. In one group, the femoral cavity was prepared by a CT-based robot (CASPAR, URS-Ortho, Germany) with a high-speed milling head. In the other group, femora were rasped manually with broaches. The broaches had 1 mm proximal press-fit, the robotic cavities 1.5 mm. The implants were exposed to 15 000 loading cycles with 1 000 +/- 500 N. The direction of forces on the implant head were chosen to simulate stair climbing. Internal rotation and translation (caudal, dorsal and lateral) of the implants were measured by linear transducers. The robotic group showed significantly less reversible motion regarding translation in caudal, dorsal and lateral directions. The standard deviations of implant motions were smaller in the robotic group. Using robotic preparation of the femur, initial stability was higher and more consistent than with manual broaching, but differences in undersizing of the cavities created in the femur in relation to the implant may have contributed to these differences for the most part. In-vitro-loading experiments focusing on femoral cavities with varying press-fits are recommended before the introduction of new implants or operating procedures.

  16. Comparison of manual rasping and robotic milling for short metaphyseal-fitting stem implantation in total hip arthroplasty: a cadaveric study.

    PubMed

    Lim, Seung-Jae; Kim, Sang-Min; Lim, Byung-Ho; Moon, Young-Wan; Park, Youn-Soo

    2013-01-01

    The ROBODOC system offers the theoretical advantage of providing better fit and mechanical stability of the stem in total hip arthroplasty. However, there has been no previous study on short metaphyseal-fitting stem implantation using the ROBODOC system. The aim of the present study was to compare the implant position and primary stability of short metaphyseal-fitting stems implanted by robotic milling and manual rasping in a human cadaveric femoral model. Eight matched pairs of human cadaveric femora were randomly assigned to a robotic milling group or manual rasping group. Operative time and intraoperative femoral fractures were monitored, and radiographic evaluation of stem alignment was performed by comparison of preoperative planning and postoperative CT data. Stability testing was performed on six matched pairs of femora, excluding two specimens in which intraoperative fractures occurred. The robotic milling procedures took an average of 27 minutes longer than the manual rasping procedures (p < 0.001). The robotic milling group exhibited significantly better anteroposterior alignment and vertical seating, and also showed a significantly reduced variability in both alignment and vertical seating. No intraoperative femoral fracture was detected in the robotic milling group, whereas two femoral fractures and one femoral stem tip perforation were detected in the manual rasping group. Stability testing showed no significant difference in translational and rotational migrations between the two groups, although the robotic milling group showed a trend towards reduced variability of stability. Our cadaveric study suggests that the use of the ROBODOC system for short metaphyseal-fitting stem implantation may have advantages in improving implant fit and reducing the risk of intraoperative femoral fractures without compromising primary stability.

  17. First insight on the impact of an osteoblastic layer on the bio-tribocorrosion performance of Ti6Al4V hip implants.

    PubMed

    Runa, M J; Mathew, M T; Fernandes, M H; Rocha, L A

    2015-01-01

    In uncemented Ti6Al4V hip implants, the bone-stem interface is subjected to cyclic loading motion driven by the daily activities of the patients, which may lead to the complete failure of the implant in the long term. It may also compromise the proliferation and differentiation processes of osteoblastic cells (bone-forming cells). The main objective of this work is to approach for the first time the role of these organic materials on the bio-tribocorrosion mechanisms of cultured Ti6Al4V alloys. The colonized materials with MG63 osteoblastic-like cells were characterized through cell viability/proliferation and enzymatic activity. Tribocorrosion tests were performed under a reciprocating sliding configuration and low contact pressure. Electrochemical techniques were used to measure the corrosion kinetics of the system, under free potential conditions. All tests were performed at a controlled atmosphere. The morphology and topography of the wear scar were evaluated. The results showed that the presence of an osteoblastic cell layer on the implant surface significantly influences the tribocorrosion behavior of Ti6Al4V alloy. It was concluded that the cellular material was able to form an extra protective layer that inhibits further wear degradation of the alloy and decreases its corrosion tendency. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Comparative effectiveness of ceramic-on-ceramic implants in stemmed hip replacement: a multinational study of six national and regional registries.

    PubMed

    Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy

    2014-12-17

    The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard

  19. Development of advanced biantibiotic loaded bone cement spacers for arthroplasty associated infections.

    PubMed

    Parra-Ruíz, F J; González-Gómez, A; Fernández-Gutiérrez, M; Parra, J; García-García, J; Azuara, G; De la Torre, B; Buján, J; Ibarra, B; Duocastella-Codina, L; Molina-Crisol, M; Vázquez-Lasa, B; San Román, J

    2017-02-28

    The incidence increase of infections in patients with hip or knee implants with resistant pathogens (mainly some S. coagulase-negative and gram positive bacteria) demands advanced antibiotic loaded formulations. In this paper, we report the design of new biantibiotic acrylic bone cements for in situ delivery. They include a last generation antibiotic (daptomycin or linezolid) in combination with vancomycin and are performed based on a novel modification of the Palacos R(®) acrylic bone cement, which is based on two components, a liquid (methyl methacrylate) and a solid (polymeric phase). Hence, the solid component of the experimental formulations include 45wt% of microparticles of poly(D,L-lactic-co-glycolic) acid, 55wt% of poly(methyl methacrylate) beads and supplements (10wt-% each) of antibiotics. These formulations provide a selective and excellent control of the local release of antibiotics during a long time period (up to 2 months), avoiding systemic dissemination. The antimicrobial activity of the advanced spacers tested against S. aureus shows that single doses would be enough for the control of the infection. In vitro biocompatibility of cements on human osteoblasts is ensured. This paper is mainly focused on the preparation and characterization of cements and the studies of elution kinetics and bactericidal effects. Developed formulations are proposed as spacers for the treatment of infected arthroplasties, but also, they could be applied in other antibiotic devices to treat relevant bone-related infection diseases.

  20. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre

    PubMed Central

    Sabah, S. A.; Henckel, J.; Cook, E.; Whittaker, R.; Hothi, H.; Pappas, Y.; Blunn, G.; Skinner, J. A.; Hart, A. J.

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67 045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:10–18. PMID:25568407

  1. Steady-state elastohydrodynamic lubrication analysis of a metal-on-metal hip implant employing a metallic cup with an ultra-high molecular weight polyethylene backing.

    PubMed

    Liu, F; Wang, F C; Jin, Z M; Hirt, F; Rieker, C; Grigoris, P

    2004-01-01

    The elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a 28 mm diameter metal-on-metal hip prosthesis employing a metallic cup with an ultra-high molecular weight polyethylene (UHMWPE) backing under a simple steady state rotation representing the flexion/extension during walking. Both Reynolds and elasticity equations were coupled and solved numerically by the finite difference method. The elastic deformation was determined by means of the fast Fourier transform (FFT) technique using the displacement coefficients obtained from the finite element method. Excellent agreement of the predicted elastic deformation was obtained between the FFT technique and the conventional direct summation method. The number of grid points used in the lubrication analysis was found to be important in predicting accurate film thicknesses, particularly at low viscosities representative of physiological lubricants. The effect of the clearance between the femoral head and the acetabular cup on the predicted lubricant film thickness was shown to be significant, while the effect of load was found to be negligible. Overall, the UHMWPE backing was found not only to reduce the contact pressure as identified in a previous study by the authors (Liu et al., 2003) but also significantly to increase the lubricant film thickness for the 28 mm diameter metal-on-metal hip implant, as compared with a metallic mono-block cup.

  2. Revision of late periprosthetic infections of total hip endoprostheses: pros and cons of different concepts

    PubMed Central

    Fink, Bernd

    2009-01-01

    Many concepts have been devised for the treatment of late periprosthetic infections of total hip prostheses. A two-stage revision with a temporary antibiotic-impregnated cement spacer and a cemented prosthesis appears to be the most preferred procedure although, in recent times, there seems to be a trend towards cementless implants and a shorter period of antibiotic treatment. Because of the differences in procedure, not only between studies but also within studies, it cannot be decided which period of parenteral antibiotic treatment and which spacer period is the most suitable. The fact that comparable rates of success can be achieved with different treatment regimens emphasises the importance of surgical removal of all foreign materials and the radical debridement of all infected and ischaemic tissues and the contribution of these crucial procedures to the successful treatment of late periprosthetic infections. PMID:19834595

  3. Preliminary results of implantation in animal model and osteoblast culture evaluation of prototypes of biomimetic multispiked connecting scaffold for noncemented stemless resurfacing hip arthroplasty endoprostheses.

    PubMed

    Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Kędzia, Andrzej; Ruszkowski, Piotr

    2013-01-01

    We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing.

  4. Long-term response of femoral density to hip implant and bone fracture plate: Computational study using a mechano-biochemical model.

    PubMed

    Avval, Pouria Tavakkoli; Samiezadeh, Saeid; Bougherara, Habiba

    2016-02-01

    Although bone fracture plates can provide appropriate stability at the fracture site and lead to early patient mobilization, they significantly change the loading pattern in the bone after union (Stress shielding). This phenomenon results in a bone density decrease, which may cause premature failure of the implant. This paper presents the first study that quantifies the long-term response of femoral density to hip implantation and plating (lateral and anterior plating) using a mechano-biochemical model which considers the coupling effect between mechanical loading and biochemical affinities as stimuli for bone remodeling. The results showed that the regions directly beneath the plate experienced severe bone loss (i.e. up to ∼ -70%). However, some level of bone formation was observed in the vicinity of the most proximal and distal screw holes in both lateral and anterior plated femurs (i.e. up to ∼ +110%). The bone under the plate was divided into six zones. With respect to bone remodeling response, the findings revealed that anterior plating was not superior to lateral plating since the maximum and average bone losses among the zones in the anterior plated femur (i.e. -36% and -24%, respectively) were approximately the same as their corresponding values in the lateral plated femur (i.e. -38% and -24%, respectively). Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Anaphylactic shock during cement implantation of a total hip arthroplasty in a patient with underlying mastocytosis: case report of a rare intraoperative complication.

    PubMed

    Ten Hagen, Anita; Doldersum, Pieter; van Raaij, Tom

    2016-01-01

    Cemented total hip arthroplasty (THA) is a safe and common procedure. In rare cases life threatening bone cement implantation syndrome (BCIS) may occur, which is commonly caused by pulmonary embolism (PE). We describe the rare case of a 70-year old patient who underwent an elective total hip replacement. Before surgery he was diagnosed with underlying systemic indolent mastocytosis, a rare pathological disorder that may result in anaphylaxis after massive systemic mast cell activation. Triggers may be IgE-mediated, direct mast cell activation, or unclear. Some patients may be at risk for severe non IgE-mediated reactions, such as those experienced with nonsteroidal anti-inflammatory drugs, or with perioperative muscle relaxants. During cementing of the acetabular component, our patient developed acute hypotension (blood pressure dropped from 90/50 to 60/40 mmHg, and saturation dropped from 95 to 80 %). The differential diagnosis of acute PE was excluded (no signs of breathing abnormalities during physical examination, normal arterial blood sample, and no electrocardiography or cardiac ultrasound abnormalities). The patient was diagnosed with acute anaphylactic shock, which was successfully managed by 100 % oxygen administration, rapid fluid induction, and vasoconstrictive drug therapy. He recovered hemodynamically within 15 min, did not lose consciousness, and did not develop angioedema or an urticarial rash. Forty-five minutes after onset of the symptoms, the surgical procedure was completed after inserting a press fitted uncemented femoral stem component. The patient was transported to the Intensive Care Unit (ICU) for optimal monitoring. Our patient had an uneventful recovery. Within six hours after surgery he started to ambulate following our standard fast-track rehabilitation regime. Post-operative day one he was discharged to the specialized Orthopedic Department, and after five hospital days discharged to his home. Twelve months after THA surgery our

  6. Arthroscopic treatment of unstable total hip replacement.

    PubMed

    Cuéllar, Ricardo; Aguinaga, Iñaki; Corcuera, Irene; Ponte, Juan; Usabiaga, Jaime

    2010-06-01

    Hip arthroscopy may be useful in the diagnosis and treatment of apparently well-implanted but unstable total hip replacement prostheses. We present 2 cases of arthroscopically assisted capsular tightening in unstable total hip replacements. Both cases had significant capsular laxity. Case 2 had impingement of the lower part of the acetabulum with the lesser trochanter that caused hip dislocation. Early revision surgery can be avoided with the use of this technique in selected cases of unstable total hip replacements.

  7. [Surgical treatment of hip osteoarthritis: update in total hip arthroplasty].

    PubMed

    Ilizaliturri Sánchez, Víctor M; Mangino Pariente, Gerardo; Camacho Galindo, Javier

    2007-10-01

    Total hip replacement is one of the most successful procedures in orthopaedic surgery. There are two different technologies for implant fixation in total hip replacement: cemented and cementless, both can be combined, which is called Hybrid arthroplasty. Long term implant stability results in long term function. The most important factor that limits longevity of well-fixed implants is the wear of the articular surfaces. Wear of the polyethylene from the acetabulum generates particles that access the implant bone or the implant-cement-bone interface. This produces an inflammatory reaction, osteolysis and implant loosening. Polyethylene of higher resistance to wear and prosthetic articulations without polyethylene (hard on hard bearings), have been introduced to improve wear particle generation. Minimally invasive surgical techniques minimize surgical trauma to sort tissue around the hip joint, facilitating a better and more rapid recovery.

  8. Multi-disciplinary antimicrobial strategies for improving orthopaedic implants to prevent prosthetic joint infections in hip and knee.

    PubMed

    Getzlaf, Matthew A; Lewallen, Eric A; Kremers, Hilal M; Jones, Dakota L; Bonin, Carolina A; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C; Lewallen, David G; van Wijnen, Andre J

    2016-02-01

    Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria.

  9. Multi-Disciplinary Antimicrobial Strategies for Improving Orthopaedic Implants to Prevent Prosthetic Joint Infections in Hip and Knee

    PubMed Central

    Getzlaf, Matthew A.; Lewallen, Eric A.; Kremers, Hilal M.; Jones, Dakota L.; Bonin, Carolina A.; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C.; Lewallen, David G.; van Wijnen, Andre J.

    2016-01-01

    Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria. PMID:26449208

  10. Effect of bearing geometry and structure support on transient elastohydrodynamic lubrication of metal-on-metal hip implants.

    PubMed

    Liu, Feng; Jin, Zhongming; Roberts, Paul; Grigoris, Peter

    2007-01-01

    An effective lubrication can significantly reduce wear of metal-on-metal artificial hip joints. The improvement of the lubrication can be achieved through the optimisation of the bearing geometry in terms of a small clearance and/or the structural support such as a polyethylene backing underneath a metallic bearing in a sandwich acetabular cup form. The separate effects of these two factors on fluid film lubrication of 28 mm diameter metal-on-metal total hip joints under walking conditions were numerically investigated in this paper. The results show that a larger lubricant film due to the polyethylene backing can be significantly enhanced by the transient squeeze-film action, particularly during the stance phase, and a similar lubricant film can be developed for both the monolithic cup relying on the smaller clearance and the sandwich cup benefiting from the polyethylene backing. Both cup systems can function in a wide range of lubrication regimes, covering both mixed and fluid film, under the current design and manufacture conditions.

  11. Block-step asymmetry 5 years after large-head metal-on-metal total hip arthroplasty is related to lower muscle mass and leg power on the implant side.

    PubMed

    Hjorth, M H; Stilling, M; Lorenzen, N D; Jakobsen, S S; Soballe, K; Mechlenburg, I

    2014-06-01

    Metal-on-metal articulations mimic the human hip anatomy, presumably lower dislocation rates and increase the range-of-motion. This study aims to measure the muscle mass and power of both legs in patients with unilateral metal-on-metal total hip arthroplasty, and to investigate their effect on block-step test, spatio-temporal gait parameters and self-reported function. Twenty-eight patients (7 women), mean age 50 (28-68) years, participated in a 5-7 year follow-up. Patients had received one type unilateral large-head metal-on-metal total hip articulation, all of which were well-functioning at follow-up. Mean muscle mass was measured by the total-body Dual energy X-ray Absorption scans, and muscle power was measured in a leg extensor power rig. Block-step test and spatio-temporal gait parameters were measured with an inertial measurement unit. Self-reported function was assessed by the Hip Disability and Osteoarthritis Outcome Score. We found a significant difference between the mean muscle mass of the implant-side leg and the non-implant-side leg in hip, thigh and calf areas (P<0.008) and in mean muscle power (P=0.025). Correlations between mean muscle mass and mean muscle power were significant for both the implant-side leg (r=0.45, P=0.018) and the non-implant-side leg (r=0.51, P=0.007). The difference in mean muscle power between legs correlated with block-step test asymmetry during ascending (r=0.40, P=0.047) and descending (r=0.53, P=0.006). Correlations between self-reported function and power of the implant-side leg were not significant. Young patients have not fully regained muscle mass, muscle power and function 5-7 years after metal-on-metal total hip arthroplasty. Copyright © 2014. Published by Elsevier Ltd.

  12. The stability of dual-taper modular hip implants: a biomechanical analysis examining the effect of impact location on component stability.

    PubMed

    Frisch, Nicholas B; Lynch, Jonathan R; Banglmaier, Richard F; Silverton, Craig D

    2017-06-01

    The purpose of this study was to investigate the stability of dual-taper modular implants following impaction forces delivered at varying locations as measured by the distraction forces required to disassemble the components. Distraction of the head-neck and neck-stem (NS) tapers of dual-taper modular implants with 0°, 8°, and 15° neck angles were measured utilizing a custom-made distraction fixture attached to a servohydraulic materials test machine. Distraction was measured after hand pressing the components as well as following a simulated firm hammer blow impaction. Impacts to the 0°, 8°, 15° necks were directed axially in line with the neck, 10° anterior, and 10° proximal to the axis of the neck, respectively. Impaction increased the range of NS component distraction forces when compared to hand pressed components (1125-1743 N vs 248-302 N, respectively). Off-axis impacts resulted in significantly reduced mean (±95% confidence interval) distraction forces (8° neck, 1125 ± 117 N; 15° neck, 1212 ± 73 N), which were up to 35% lower than the mean distraction force for axial impacts to the 0° neck (1743 ± 138 N). Direction of impaction influences stability of the modular interface. The greatest stability was achieved with impaction directed in line with the longitudinal axis of the taper junction. Off-axis impaction of the 8° and 15° neck led to significantly reduced stability at the NS. Improving stability of dual-taper modular hip prostheses with appropriately directed impaction may help to minimize micromotion, component settling, fretting corrosion, and subsequent failure.

  13. An Analytical Calculation of Frictional and Bending Moments at the Head-Neck Interface of Hip Joint Implants during Different Physiological Activities.

    PubMed

    Farhoudi, Hamidreza; Oskouei, Reza H; Pasha Zanoosi, Ali A; Jones, Claire F; Taylor, Mark

    2016-12-05

    This study predicts the frictional moments at the head-cup interface and frictional torques and bending moments acting on the head-neck interface of a modular total hip replacement across a range of activities of daily living. The predicted moment and torque profiles are based on the kinematics of four patients and the implant characteristics of a metal-on-metal implant. Depending on the body weight and type of activity, the moments and torques had significant variations in both magnitude and direction over the activity cycles. For the nine investigated activities, the maximum magnitude of the frictional moment ranged from 2.6 to 7.1 Nm. The maximum magnitude of the torque acting on the head-neck interface ranged from 2.3 to 5.7 Nm. The bending moment acting on the head-neck interface varied from 7 to 21.6 Nm. One-leg-standing had the widest range of frictional torque on the head-neck interface (11 Nm) while normal walking had the smallest range (6.1 Nm). The widest range, together with the maximum magnitude of torque, bending moment, and frictional moment, occurred during one-leg-standing of the lightest patient. Most of the simulated activities resulted in frictional torques that were near the previously reported oxide layer depassivation threshold torque. The predicted bending moments were also found at a level believed to contribute to the oxide layer depassivation. The calculated magnitudes and directions of the moments, applied directly to the head-neck taper junction, provide realistic mechanical loading data for in vitro and computational studies on the mechanical behaviour and multi-axial fretting at the head-neck interface.

  14. Total hip prosthesis complication, periprosthetic infection with external fistulizing due to Enterobacter cloacae complex multiple drugs resistance: A clinical case report.

    PubMed

    Amorese, V; Corda, M; Donadu, M; Usai, D; Pisanu, F; Milia, F; Marras, F; Sanna, A; Delogu, D; Mazzarello, V; Manzoni, G; Conti, M; Meloni, G B; Zanetti, S; Doria, C

    2017-01-01

    The Enterobacter cloacae is a microorganism found in the intestinal flora of the majority of animals, including humans. Primary infections caused by E. cloacae are rare in immunocompetent patients, but are very common in hospital settings in newborns and immunocompromised patients, and can be aggravated by the insurgence of antibiotic resistance. The incidence of periprosthetic hip infections is just below 2%. A 76year old woman with multiple comorbidities underwent surgical implantation of intermediary total hip prosthesis of the left hip, in a different health facility, in February 2014, after the basicervical fracture of the upper femur extremity due to trauma. After an episode of dislocation of the prosthetic implant, in September 2014, she underwent a surgical operation to implant the acetabular component. A month later not in our facility, following a re-hospitalization for the dislocation of the arthroprosthesis, an infection from E. cloacae complex was discovered. After 2 years of chronic infection she came to our attention; the clinical picture featured coxalgia and secreting fistula in the surgical wound. Following a specific antibiotic therapy, carried out intravenously over the course of a month, we decided to intervene removing the left hip arthroprosthesis and placing an antibiotic spacer following the direction deduced from the antibiogram study of August 2016. The patient was hospitalized in our facility and 2 months later she underwent another operation to remove the antibiotic spacer and to place a new total hip arthroprosthesis. Multiple swabs showed the complete healing from the infection, which was confirmed a couple of months later. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Improving Resident Knowledge of Spacers.

    PubMed

    Kilgore, Brian; Al Katranji, Khalid; Woodall, Meredith; Shepherd, Meagan; Flesher, Susan L

    2016-10-01

    Studies show the delivery of inhaled medications is maximized when a metered-dose inhaler (MDI) with a spacer is utilized. Our residents expressed concern with their knowledge of MDIs and spacers. This study was designed to address those concerns. Residents were given a 12-question pre-intervention, self-assessment questionnaire that explored their overall knowledge and comfort in utilizing MDI with spacers. Participants then received educational intervention via multimedia videos and a demonstration of proper use of MDI with spacer. Participants were given the same questionnaire immediately following the education and again 3 months later. Improvement was significant (P < .05) for each element studied as derived from the 12 questions. Improvement remained significant when these variables were assessed in the 3-month follow-up. In this study, we successfully improved the ability of our residents to deliver quality care by improving their knowledge and confidence in utilizing MDIs with spacers. © The Author(s) 2016.

  16. Accuracy of methods for calculating volumetric wear from coordinate measuring machine data of retrieved metal-on-metal hip joint implants.

    PubMed

    Lu, Zhen; McKellop, Harry A

    2014-03-01

    This study compared the accuracy and sensitivity of several numerical methods employing spherical or plane triangles for calculating the volumetric wear of retrieved metal-on-metal hip joint implants from coordinate measuring machine measurements. Five methods, one using spherical triangles and four using plane triangles to represent the bearing and the best-fit surfaces, were assessed and compared on a perfect hemisphere model and a hemi-ellipsoid model (i.e. unworn models), computer-generated wear models and wear-tested femoral balls, with point spacings of 0.5, 1, 2 and 3 mm. The results showed that the algorithm (Method 1) employing spherical triangles to represent the bearing surface and to scale the mesh to the best-fit surfaces produced adequate accuracy for the wear volume with point spacings of 0.5, 1, 2 and 3 mm. The algorithms (Methods 2-4) using plane triangles to represent the bearing surface and to scale the mesh to the best-fit surface also produced accuracies that were comparable to that with spherical triangles. In contrast, if the bearing surface was represented with a mesh of plane triangles and the best-fit surface was taken as a smooth surface without discretization (Method 5), the algorithm produced much lower accuracy with a point spacing of 0.5 mm than Methods 1-4 with a point spacing of 3 mm.

  17. A new, simple method of making a spacer in interstitial brachytherapy for mobile tongue cancer.

    PubMed

    Yuasa, K; Kawazu, T; Morita, M; Uehara, S; Kunitake, N; Kanda, S

    2000-04-01

    This article demonstrates a new method of making a spacer that increases the distance between the mandible and implanted radioactive sources in interstitial brachytherapy for patients with mobile tongue cancer. Fifty-three patients with mobile tongue cancer underwent interstitial brachytherapy with spacers made by this new technique. Our spacer is not difficult to create or to use. The spacer was made from a plastic splint by using thermoforming techniques and quick self-curing resin, which did not need waxing, wiring, or casting. The surface of the spacer, which comes in contact with the tongue, is smooth because it is covered with tissue-conditioning material. There were no complaints of pain from the patients. Osteoradionecrosis of the mandible developed in only 1 (1.9%) of these patients. This spacer is simple to make and prevented osteoradionecrosis.

  18. Cementless hydroxyapatite coated hip prostheses.

    PubMed

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda; Gracia, Luis

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

  19. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  20. Hip Pain

    MedlinePlus

    ... clues about the underlying cause. Problems within the hip joint itself tend to result in pain on the ... tendons and other soft tissues that surround your hip joint. Hip pain can sometimes be caused by diseases ...

  1. Review of cobalt toxicokinetics following oral dosing: Implications for health risk assessments and metal-on-metal hip implant patients.

    PubMed

    Tvermoes, Brooke E; Paustenbach, Dennis J; Kerger, Brent D; Finley, Brent L; Unice, Kenneth M

    2015-05-01

    Cobalt (Co) can stimulate erythropoietin production in individuals at doses exceeding 25 mg CoCl2/day. Co has also been shown to exert effects on the thyroid gland, heart and nervous system at sufficient doses. The biological activity of Co is dictated by the concentration of free (unbound) ionic Co(2+). Blood concentrations, as well as, urinary excretion rates of Co are reliable biomarkers for systemic Co exposure. A recent series of human volunteer Co-supplement studies simultaneously measured Co blood and urine concentrations, as well as, Co speciation in serum, and a number of biochemical and clinical parameters. It was found in these studies that peak Co whole blood concentration as high as 117 μg/L were not associated with changes in hematological parameters such as increased red blood cell (RBC) count, hemoglobin (Hgb) or hematocrit (Hct) levels, nor with changes in cardiac, neurological or, thyroid function. Using a Co biokinetic model, the estimated Co systemic tissue concentrations (e.g., liver, kidney, and heart) following 90-days of Co-dietary supplementation with ∼1 mg Co/day were found to be similar to estimated tissue concentrations in implant patients after 10 years of exposure at continuous steady state Co blood concentration of ∼10 μg/L. This study is the first to present modeled Co tissue concentrations at various doses following sub-chronic and chronic exposure. The modeled steady state tissue Co concentrations in combination with the data on adverse health effects in humans should help in the characterization of potential hazards associated with increased blood Co concentrations due to exposure to dietary supplements or cobalt-chromium (Co-Cr) containing implants.

  2. Usefulness of Prosthesis Made of Antibiotic-Loaded Acrylic Cement as an Alternative Implant in Older Patients With Medical Problems and Periprosthetic Hip Infections: A 2- to 10-Year Follow-Up Study.

    PubMed

    Lee, Woo-Yong; Hwang, Deuk-Soo; Kang, Chan; Shin, Byung-Kon; Zheng, Long

    2017-01-01

    The purpose of this study was to compare the clinical outcomes after 2-stage revision with those following single-stage revision in patients who developed periprosthetic joint infection after primary hip arthroplasty. Between January 2004 and January 2013, we retrospectively reviewed patients who developed periprosthetic joint infection after primary hip arthroplasty and who underwent surgery for placement of a prosthesis made of antibiotic-loaded acrylic cement (PROSTALAC). Patients were divided into 2 groups based on the stages of revision. Group A was made up of patients who had undergone 2-stage revision using PROSTALAC as an interim prosthesis. Group B was made up of patients who had been compelled to undergo single-stage revision using PROSTALAC as an alternative implant because of older age and/or medical problems. Clinical outcomes were evaluated using a visual analog scale to score pain by calculating the Harris Hip Score and by determining the patient's walking ability. There were 20 patients in group A and 19 patients in group B. The mean follow-up period after final surgery was 68.8 months (range, 24-114 months). The infection resolution rate after initial PROSTALAC placement was 92.3%, and the final resolution rate was 94.9%. The visual analog scale and Harris Hip Score of group A were significantly better than those of group B. However, no significant difference in walking ability was found between the 2 groups. Although the clinical outcomes in patients with PROSTALAC implants were not as good as those who underwent 2-stage revision, PROSTALAC can be a useful alternative implant in selected patients who are debilitated because of older age and/or who have critical medical problems. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Magnetic resonance imaging evaluation of intervertebral test spacers: an experimental comparison of magnesium versus titanium and carbon fiber reinforced polymers as biomaterials.

    PubMed

    Ernstberger, T; Buchhorn, G; Heidrich, G

    2010-03-01

    Intervertebral spacers are made of different materials, which can affect the postfusion magnetic resonance imaging (MRI) scans. Susceptibility artifacts, especially for metallic implants, can decrease the image quality. This study aimed to determine whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior. To compare artifacting behaviors, we implanted into one porcine cadaveric spine different test spacers made of magnesium, titanium, and CFRP. All test spacers were scanned using two T1-TSE MRI sequences. The artifact dimensions were traced on all scans and statistically analyzed. The total artifact volume and median artifact area of the titanium spacers were statistically significantly larger than magnesium spacers (P < 0.001), while magnesium and CFRP spacers produced almost identical artifacting behaviors (P > 0.05). Our results suggest that spinal implants made with magnesium alloys will behave more like CFRP devices in MRI scans.

  4. Comparison of Whole-Blood Metal Ion Levels Among Four Types of Large-Head, Metal-on-Metal Total Hip Arthroplasty Implants: A Concise Follow-up, at Five Years, of a Previous Report.

    PubMed

    Hutt, Jonathan; Lavigne, Martin; Lungu, Eugen; Belzile, Etienne; Morin, François; Vendittoli, Pascal-André

    2016-02-17

    Few studies of total hip arthroplasty (THA) implants with a large-diameter femoral head and metal-on-metal design have directly compared the progression of metal ion levels over time and the relationship to complications. As we previously reported, 144 patients received one of four types of large-diameter-head, metal-on-metal THA designs (Durom, Birmingham, ASR XL, or Magnum implants). Cobalt, chromium, and titanium ion levels were measured over five years. We compared ion levels and clinical results over time. The Durom group showed the highest levels of cobalt (p ≤ 0.002) and titanium ions (p ≤ 0.03). Both the Durom and Birmingham groups demonstrated significant ongoing cobalt increases up to five years. Eight patients (seven with a Durom implant and one with a Birmingham implant) developed adverse local tissue reaction. Six Durom implants and one Birmingham implant required revision, with one pseudotumor under surveillance at the time of the most recent follow-up. We found that ion generation and related complications varied among designs. More concerning was that, for some designs, ion levels continued to increase. Coupling a cobalt-chromium adapter sleeve to an unmodified titanium femoral trunnion along with a large metal-on-metal bearing may explain the poor performances of two of the designs in the current study.

  5. Ertapenem Articulating Spacer for the Treatment of Polymicrobial Total Knee Arthroplasty Infection

    PubMed Central

    Marinkovic, Jugoslav

    2016-01-01

    Introduction. Periprosthetic joint infections (PJIs) are the primary cause of early failure of the total knee arthroplasty (TKA). Polymicrobial TKA infections are often associated with a higher risk of treatment failure. The aim of the study was to assess the efficacy of ertapenem loaded spacers in the treatment of polymicrobial PJI. Methods. There were 18 patients enrolled; nine patients with polymicrobial PJI treated with ertapenem loaded articulating spacers were compared to the group of 9 patients treated with vancomycin or ceftazidime loaded spacers. Results. Successful reimplantation with revision implants was possible in 66.67%. Ertapenem spacers were used in 6 cases in primary two-stage procedure and in 3 cases in secondary spacer exchange. Successful infection eradication was achieved in all cases; final reimplantation with revision knee arthroplasty implants was possible in 6 cases. Conclusion. Ertapenem can be successfully used as antimicrobial addition to the cement spacers in two-stage revision treatment of polymicrobial PJIs. However, this type of spacer may also be useful in the treatment of infections caused by monomicrobial extended spectrum beta-lactamases producing gram-negative bacilli. Further clinical studies are required to evaluate the efficacy and safety of ertapenem spacers in the treatment of polymicrobial and monomicrobial PJIs. PMID:27366173

  6. Three-dimensional computerized selection of hip prostheses in patients with congenital dislocated hips.

    PubMed

    Gelalis, L D; Xenakis, T A; Hantes, M; Vartziotis, K; Soucacos, P N

    2001-11-01

    This study assessed the effectiveness of the combined use of computed tomography (CT) and computer-aided design (CAD) in the preoperative evaluation and implant selection in 20 patients (20 hips) with congenital dislocation of the hip who were scheduled to undergo total hip arthroplasty. Computerized selection of the femoral implant with optimum fit and fill was made after a three-dimensional reconstruction of the femoral canal using CT data and CAD. Implantation of all sizes of 5 noncemented and 2 cemented femoral implants was simulated using CATIA software (IBM, Kingstone, NY). When patients underwent surgery, 18 of 20 preselected prostheses agreed by type and size with the prostheses implanted. The remaining 2 preselected implants agreed by type only. In patients with dislocated and dysplastic hips, combined use of CT and CAD allows effective preoperative planning by providing the surgeon with vital information about the proximal femoral canal geometry and the possible femoral implant with optimum fit and fill to be used.

  7. Perforation of the sigmoid colon due to intradiscal spacer dislocation.

    PubMed

    Ruf, Michael; Voigt, Andreas; Kupczyk-Joeris, Dieter; Merk, Harry R

    2011-07-01

    A case of late dislocation of a disc spacer L5/S1 with perforation of the sigmoid colon and transanal passage 4 years after implantation is reported. The objective is to describe an uncommon complication of anterior endoscopic spondylodesis L5/S1. To our knowledge, this is the first report on this rare complication. A 39-year-old patient suffering from a spondylolisthesis L5/S1 (Meyerding grade 2) with bilateral lysis L5 was operated with posterior instrumentation L5/S1 and anterior endoscopic insertion of two disc spacers. 4 years after surgery the patient noticed one of the spacers in the toilet. Radiographic examination of the colon with contrast dye revealed a perforation at the distal sigmoid colon. At the lumbosacral junction there was a bony defect at the site of the absent spacer and an anterior dislocation of the second spacer. A partial resection of the colon at the perforation site with end-to-end anastomosis was performed. The second spacer was removed, and the defect was packed with autologous cancellous bone and local antibiotics. The further course was uneventful. 2 weeks postoperatively the patient was discharged without signs of infection. The radiographic examination after 6 months showed healing of the bone graft with bony fusion L5/S1. In case of incomplete or absent bony fusion the dislocation of intradiscal spacers may arise even years after the primary surgery. In consequence periodical radiographic examinations of spinal instrumentations are recommended until complete bony fusion occurred. Unclear abdominal symptoms following anterior spine surgery require immediate examination.

  8. Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy

    SciTech Connect

    Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G.; Sridhar, Srinivas

    2015-02-01

    Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when

  9. Scanning Electron Microscopy and Energy-Dispersive X-Ray Spectroscopy as a Valuable Tool to Investigate the Ultra-High-Molecular-Weight Polyethylene Wear Mechanisms and Debris in Hip Implants.

    PubMed

    Schappo, Henrique; Gindri, Izabelle M; Cubillos, Patrícia O; Maru, Marcia M; Salmoria, Gean V; Roesler, Carlos R M

    2017-08-01

    The use of scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS) was investigated to understand the wear mechanisms from a metal-on-polyethylene bearing couple. Morphological features of femoral head acetabular liner, and isolated particles resulting from hip wear testing were evaluated. EDS was proposed to investigate the polymeric nature of the particles isolated from the wear testing. In this work, 28-mm conventional ultra-high-molecular-weight polyethylene acetabular liners paired with metallic heads were tested in a hip wear simulator over 2 million cycles. SEM-EDS was employed to investigate wear mechanisms on hip implant components and associated wear debris. SEM showed worn surfaces for both hip components, and a significant volume of ultra-high-molecular-weight polyethylene wear particles resulting from hip wear testing. Particles were classified into 3 groups, which were then correlated to wear mechanisms. Group I had particles with smooth surfaces, group II consisted of particles with rough surfaces, and group III comprised aggregate-like particles. Group I EDS revealed that particles from groups I and II had a high C/O ratio raising a concern about the particle source. On the other hand, particles from group III had a low C/O ratio, supporting the hypothesis that they resulted from the wear of acetabular liner. Most of particles identified in group III were in the biologically active size range (0.3 to 20 μm). The use of optical and electron microscopy enabled the morphological characterization of worn surfaces and wear debris, while EDS was essential to elucidate the chemical composition of isolated debris. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Staged total hip arthroplasty in a patient with hip dysplasia and a large pertrochanteric bone cyst.

    PubMed

    Langston, Joseph R; DeHaan, Alexander M; Huff, Thomas W

    2016-06-01

    Hip arthroplasty in young patients requires thoughtful preoperative planning. Patients with proximal femoral bone loss complicate this planning and may require a staged procedure to optimize implant insertion. We report on a case of a 26-year-old woman with secondary hip arthritis from developmental dysplasia of the hip and a large pertrochanteric bone cyst that was treated with staged total hip arthroplasty. The cyst was decompressed and filled with an osteoconductive and osteoinductive bone graft substitute called EquivaBone. One year later, the patient underwent a successful primary total hip arthroplasty. Fifteen-month follow-up after her hip replacement revealed resolution of postoperative pain and significant functional improvement.

  11. Hip Fracture

    MedlinePlus

    ... make older people more likely to trip and fall — one of the most common causes of hip ... Taking steps to maintain bone density and avoid falls can help prevent hip fracture. Signs and symptoms ...

  12. Rose Hip

    MedlinePlus

    ... with your health provider.AspirinThe body breaks down aspirin to get rid of it. Rose hip contains ... of vitamin C might decrease the breakdown of aspirin. Taking large amount of rose hip along with ...

  13. Hip Replacement

    MedlinePlus

    ... exercise can reduce stiffness and increase flexibility and muscle strength. People who have an artificial hip should talk ... and cross-country skiing. These exercises can increase muscle strength and cardiovascular fitness without injuring the new hip. ...

  14. Hip Replacement

    MedlinePlus

    ... replacement is an operation in which a damaged hip joint is removed and replaced with an artificial joint. ... are many medical conditions that can damage the hip joint. (Watch the video to learn about what goes ...

  15. Hip Ultrasound

    MedlinePlus

    ... Index A-Z Hip Ultrasound Hip ultrasound uses sound waves to produce pictures of muscles, tendons, ligaments, ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  16. Biodynamic total hip prosthesis.

    PubMed

    Pipino, F; Calderale, P M

    1987-09-01

    The biodynamic total hip prosthesis which was devised in 1977-78 and implanted in 1979 was derived from a series of experimental studies and a lengthy clinical experience, both dating back to 1968. This prosthesis introduced two new and original concepts into the field of prosthetic hip surgery: 1) the biequatorial design of the cup; 2) the preservation of the femoral neck. This prosthetic system is based on maximum preservation of the bone stock as well as hip function. The biequatorial cup allows for positioning corresponding to that of the normal acetabulum. The femoral component incorporates features (collar, sagittal and frontal angulation, external surface, etc.) which facilitate proximal cortical fixation and cancellous metaphyseal biological anchoring, thus ensuring total adhesion. The average 3.5 years follow-up (maximum 7 years, minimum one year) in 280 cases confirms the effectiveness of this prosthesis and the validity of the basic principles on which it is founded.

  17. [Interspinous spacers and disc herniation. Geomorphometric and clinical study of 71 cases treated by L4-L5 microdiscectomy associated to spacer placement].

    PubMed

    Aso Escario, José; Aso Vizán, Alberto; Martínez Quiñones, José Vicente; Consolini, Fabian; Martín Gallego, Álvaro; Arregui Calvo, Ricardo

    2015-01-01

    A controversial indication of interspinous spacers is their use as a complement to discectomy. At the present time, there is no solid clinical evidence of effectiveness of that association, which might result from variability in spacer positioning, restricting its correct biomechanical actions. In this study our goal was to identify and analyse the variability in the placement of an interspinous spacer, and to investigate its relationship with the clinical results. We performed a retrospective study on X-ray films from 71 patients suffering from disc herniation in L4-L5 who underwent surgery in our hospital, consisting of: microdiscectomy and biomed interspinous spacer implantation. The geomorphometric techniques used to analyse the data were procrustes superimposition and principal components analysis. We compared the clinical results (using the Herron and Turner scale), segmental lordosis and surgical distraction with the geomorphometric parameters. Significant morphological variability was found in the implant position showing cephalo-caudal translation and clockwise-counterclockwise rotations. This variability did not correlate with clinical results. A relationship with anatomical features (lordosis) and additional surgical distraction was identified. A different morphology of implant-segment configuration was identified in cases with recurrence of disc herniation. Geometric morphometrics allowed identifying high variability in the final placement of interspinous spacers. Nevertheless, it seems not to be related to the clinical outcome, depending rather on the degree of lordosis and distraction. Some differences in segment-implant morphology were identified in cases with recurrences. To assess the effectiveness of spacers, larger studies including morphological and clinical variables are required. Copyright © 2013 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  18. [Hip joint infections - Results of a questionnaire among 28 university orthopedic departments].

    PubMed

    Anagnostakos, K; Kohn, D

    2011-09-01

    Despite numerous prophylactic measures infections still remain a hazardous complication in orthopedic surgery. A questionnaire about hip joint infections was sent to all university orthopedic departments in Germany and Austria. The questionnaire included 33 questions with respect to demographic data, causative organisms, diagnostic measures, treatment options for early and late infections, antibiotic therapy and prosthesis reimplantation. The participation rate was 70%. The most frequent primary surgical indication was primary total hip replacement and Staphylococcus aureus and S. epidermidis were the most common pathogens identified. All departments performed a joint aspiration for diagnosis confirmation but for other diagnostic measures a great discrepancy could be observed. In the treatment of early infections removable components were always exchanged, whereas a local antibiotic therapy was not always employed. With regard to late infections a two-stage protocol was more frequently used than a one-stage treatment, whereby the implantation of a cement spacer was more commonly performed than a resection arthroplasty. The time between stages varied between 6 and 12 weeks and systemic antibiotics were administered for a mean time of 6 weeks. For prosthesis reimplantion cementless components were mostly used but no clear tendency could be determined for systemic antibiotic therapy. Treatment of hip joint infections among German and Austrian university orthopedic departments is only partly carried out in a similar manner.

  19. Generator stator core vent duct spacer posts

    DOEpatents

    Griffith, John Wesley; Tong, Wei

    2003-06-24

    Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

  20. Spacer grid assembly and locking mechanism

    DOEpatents

    Snyder, Jr., Harold J.; Veca, Anthony R.; Donck, Harry A.

    1982-01-01

    A spacer grid assembly is disclosed for retaining a plurality of fuel rods in substantially parallel spaced relation, the spacer grids being formed with rhombic openings defining contact means for engaging from one to four fuel rods arranged in each opening, the spacer grids being of symmetric configuration with their rhombic openings being asymmetrically offset to permit inversion and relative rotation of the similar spacer grids for improved support of the fuel rods. An improved locking mechanism includes tie bars having chordal surfaces to facilitate their installation in slotted circular openings of the spacer grids, the tie rods being rotatable into locking engagement with the slotted openings.

  1. Development of high performance BWR spacer

    SciTech Connect

    Morooka, Shinichi; Shirakawa, Kenetu; Mitutake, Tohru; Yamamoto, Yasushi; Yano, Takashi; Kimura, Jiro

    1996-07-01

    The spacer has a significant effect on thermal hydraulic performance of BWR fuel assembly. The purpose of this study is to develop a new BWR spacer with high critical power and low pressure drop performance. The developed high performance spacer is a ferrule type spacer with twisted tape and improved flow tab. This spacer is called CYCLONE spacer. Critical power and pressure drop have been measured at BEST (BWR Experimental Loop for Stability and Transient test) of Toshiba Corporation. The test bundle consists of electrically heated rods in a 4x4 array configuration. These heater rods are indirectly heated. The heated length and outer diameter of the heater rod, as well as the number and the axial locations of the spacers, are the same as for those for a BWR fuel assembly. The axial power shape is stepped cosine (1.4 of the maximum peaking factor). Two test assemblies with different radial power distribution have been used. One test assembly has the maximum power rods at the center of the test assembly and the other has the maximum power rods near the channel wall. The results show that the critical power performance of CYCLONE spacer is 10 to 25 % higher than that of the ferrule spacers, while the pressure drop for CYCLONE spacer is nearly equal to that of the ferrule spacer.

  2. Hip arthroscopy.

    PubMed

    de Amorim Cabrita, Henrique Antônio Berwanger; de Castro Trindade, Christiano Augusto; de Campos Gurgel, Henrique Melo; Leal, Rafael Demura; de Souza Marques, Ricardo da Fonseca

    2015-01-01

    Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve.

  3. Subject-specific hip geometry affects predicted hip joint contact forces during gait.

    PubMed

    Lenaerts, G; De Groote, F; Demeulenaere, B; Mulier, M; Van der Perre, G; Spaepen, A; Jonkers, I

    2008-01-01

    Hip loading affects bone remodeling and implant fixation. In this study, we have analyzed the effect of subject-specific modeling of hip geometry on muscle activation patterns and hip contact forces during gait, using musculoskeletal modeling, inverse dynamic analysis and static optimization. We first used sensitivity analysis to analyze the effect of isolated changes in femoral neck-length (NL) and neck-shaft angle (NSA) on calculated muscle activations and hip contact force during the stance phase of gait. A deformable generic musculoskeletal model was adjusted incrementally to adopt a physiological range of NL and NSA. In a second similar analysis, we adjusted hip geometry to the measurements from digitized radiographs of 20 subjects with primary hip osteoarthrosis. Finally, we studied the effect of hip abductor weakness on muscle activation patterns and hip contact force. This analysis showed that differences in NL (41-74 mm) and NSA (113-140 degrees ) affect the muscle activation of the hip abductors during stance phase and hence hip contact force by up to three times body weight. In conclusion, the results from both the sensitivity and subject-specific analysis showed that at the moment of peak contact force, altered NSA has only a minor effect on the loading configuration of the hip. Increased NL, however, results in an increase of the three hip contact-force components and a reduced vertical loading. The results of these analyses are essential to understand modified hip joint loading, and for planning hip surgery for patients with osteoarthrosis.

  4. [Design of an unconventional interlocked hip arthroplasty system (RIMAG) from Mexican femoral measurement].

    PubMed

    Martínez, Genaro Rico; Domínguez, Víctor H; Muller, José Antonio; Cedillo, Ernesto A Delgado; Roa, Josué Antonio Miranda; Montoya, Roberto C

    2008-01-01

    The need in resolving massive bone losses in hip region caused by tumors, infections, trauma or failed arthroplasties in 17 years of the Bone Tumors Department of the National Rehabilitation Institute, Mexico City, and data obtained from different studies: 1) Biomechanic study of an unconventional hip arthroplasty system, 2) Tridimensional model of a human femur by the finite element method, 3) Biomechanical analysis of a system bone-implant for reconstruction of the proximal third of the femur by the finite element method, 4) Incidence of tumor and pseudotumor bone and soft tissue lesions of the hip, generated the project of designing an unconventional interlocked hip arthroplasty system for femur reconstruction. Two processes were done for adequate manufacturing and dimensioning: Anthropomorphometric study of Mexican femora; 2) Design of an unconventional hip arthroplasty system with the following characteristics: first, the arthroplasty system is constituted by an intramedullar stem, is fixated to femur with interlocking screws, this fixation method was inspired from the design of intramedullar nails of Dr. Fernando Colchero Rosas. The system has a second fixation system in the femur cut region, resolved by a fenestrated support introduced in the cortical wall. Once data was processed, the need for manufacturing 2 models was determined: 1) One for the proximal 11 cm of the femur and 2) other for the 12 distal cm. The height of interlocking screws, 2 models of intracortical proximal support (one fixated and one fixable with an expansible screw), were designed. Diameter, length of the stems, size of spacers and supports were determined for adequate interlocking fixation. We designed the instruments for assembling, impaction and orientation of the arthroplasty system. The system was presented to the Mexican Institute of Industrial Property, at March 15, 1996 and the patent was conceded April 19, 2007 (#245717).

  5. Curved-stem Hip Resurfacing

    PubMed Central

    2008-01-01

    Hip resurfacing is an attractive concept because it preserves rather than removes the femoral head and neck. Most early designs had high failure rates, but one unique design had a femoral stem. Because that particular device appeared to have better implant survival, this study assessed the clinical outcome and long-term survivorship of a hip resurfacing prosthesis. Four hundred forty-five patients (561 hips) were retrospectively reviewed after a minimum of 20 years’ followup or until death; 23 additional patients were lost to followup. Patients received a metal femoral prosthesis with a small curved stem. Three types of acetabular reconstructions were used: (1) cemented polyurethane; (2) metal-on-metal; and (3) polyethylene secured with cement or used as the liner of a two-piece porous-coated implant. Long-term results were favorable with the metal-on-metal combination only. The mean overall Harris hip score was 92 at 2 years of followup. None of the 121 patients (133 hips) who received metal-on-metal articulation experienced failure. The failure rate with polyurethane was 100%, and the failure rate with cemented polyethylene was 41%. Hip resurfacing with a curved-stem femoral component had a durable clinical outcome when a metal-on-metal articulation was used. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18338217

  6. Wear simulation of ultra-high molecular weight polyethylene hip implants by incorporating the effects of cross-shear and contact pressure.

    PubMed

    Kang, L; Galvin, A L; Brown, T D; Fisher, J; Jin, Z-M

    2008-10-01

    The effect of multi-directional cross-shear (CS) motion and contact pressure on ultra-high molecular weight polyethylene (UHMWPE) wear was investigated in this study, based on an integrated experimental and computational approach. The wear factor as a function of CS was determined experimentally from a multi-directional pin-on-plate wear tester under a nominal contact pressure of 1 MPa. A computational wear model was developed which included the effects of CS as well as the load and sliding distance imposed on the hip joint employing a UHMWPE cup against a metallic femoral head under both gait and Leeds ProSim hip joint simulator conditions. The CS ratios were quantified over the articular surface of the UHMWPE cup and the CS-dependent wear factors derived from multi-directional pin-on-plate studies were applied in the computational wear model. Outputs from the computational wear model were validated independently against an experimental hip simulator study. Comparisons of linear and volumetric wear were made between the computational wear model and the hip simulator testing for a nominal conventional (0 MRad) UHMWPE cup of 28mm diameter and a highly cross-linked (10 MRad) UHMWPE cup. The difference between the computed and experimental volumetric wear was approximately 30 per cent for the 0 MRad UHMWPE, although the worn areas between the prediction and the measurement were similar. For the 10 MRad UHMWPE, the discrepancy was reduced to 16 per cent. In both cases, the computational model predicted a lower wear rate than the experimental simulator testing. The effect of using alternative wear factors under a different nominal contact pressure of 3MPa was also considered. The input wear factor to the computational model, derived from a constant loaded pin-on-plate test configuration, may underestimate the dynamic effect due to the variation in the load in the hip joint simulator.

  7. Two-Stage Cementless Revision Total Hip Arthroplasty for Infected Primary Hip Arthroplasties.

    PubMed

    Camurcu, Yalkin; Sofu, Hakan; Buyuk, Abdul Fettah; Gursu, Sarper; Kaygusuz, Mehmet Akif; Sahin, Vedat

    2015-09-01

    The main purpose of the present study was to analyze the clinical features, the most common infective agents, and the results of two-stage total hip revision using a teicoplanin-impregnated spacer. Between January 2005 and July 2011, 41 patients were included. At the clinical status analysis, physical examination was performed, Harris hip score was noted, isolated microorganisms were recorded, and the radiographic evaluation was performed. The mean Harris hip score was improved from 38.9 ± 9.6 points to 81.8 ± 5.8 points (P<0.05). Infection was eradicated in 39 hips. Radiographic evidence of stability was noted in 37 acetabular revision components, and all femoral stems. Two-stage revision of the infected primary hip arthroplasty is a time-consuming but a reliable procedure with high rates of success. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Total hip replacement for hip fracture: Surgical techniques and concepts.

    PubMed

    Coomber, Ross; Porteous, Matthew; Hubble, Matthew J W; Parker, Martyn J

    2016-10-01

    When treating a hip fracture with a total hip replacement (THR) the surgical technique may differ in a number of aspects in comparison to elective arthroplasty. The hip fracture patient is more likely to have poor bone stock secondary to osteoporosis, be older, have a greater number of co-morbidities, and have had limited peri-operative work-up. These factors lead to a higher risk of complications, morbidity and perioperative mortality. Consideration should be made to performing the THR in a laminar flow theatre, by a surgeon experienced in total hip arthroplasty, using an anterolateral approach, cementing the implant in place, using a large head size and with repair of the joint capsule. Combined Ortho-geriatric care is recommended with similar post-operative rehabilitation to elective THR patients but with less expectation of short length of stay and consideration for fracture prevention measures. Copyright © 2016. Published by Elsevier Ltd.

  9. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre: a study using the NJR dataset.

    PubMed

    Sabah, S A; Henckel, J; Cook, E; Whittaker, R; Hothi, H; Pappas, Y; Blunn, G; Skinner, J A; Hart, A J

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67,045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data.

  10. Artifacts in spine magnetic resonance imaging due to different intervertebral test spacers: an in vitro evaluation of magnesium versus titanium and carbon-fiber-reinforced polymers as biomaterials.

    PubMed

    Ernstberger, Thorsten; Buchhorn, Gottfried; Heidrich, Gabert

    2009-08-01

    Intervertebral spacers are made of different materials, which can affect the postfusion magnetic imaging (MRI) scans. Susceptibility artifacts especially for metallic implants can decrease the image quality. This study aimed to determine whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior. To compare artifacting behaviors, we implanted into one porcine cadaveric spine different test spacers made of magnesium, titanium, and carbon-fiber-reinforced polymers (CFRP). All test spacers were scanned using two T1-TSE MRI sequences. The artifact dimensions were traced on all scans and statistically analyzed. The total artifact volume and median artifact area of the titanium spacers were statistically significantly larger than magnesium spacers (p < 0.001), while magnesium and CFRP spacers produced almost identical artifacting behaviors (p > 0.05). Our results suggest that spinal implants made with magnesium alloys will behave more like CFRP devices in MRI scans. Given its osseoconductive potential as a metal, implant alloys made with magnesium would combine the advantages to the two principal spacer materials currently used but without their limitations, at least in terms of MRI artifacting.

  11. [Use of gold implants as a treatment of pain related to canine hip dysplasia--a review. Part 1: Background and current state of research regarding the effects of implanting gold in tissue].

    PubMed

    Deisenroth, A; Nolte, I; Wefstaedt, P

    2013-01-01

    Gold-bead implantation as a method of pain treatment in dogs suffering from osteoarthritic disease is receiving increasing attention in veterinary medicine. For the present article, publications from veterinary books and journals were collected and evaluated, together with related articles in human medicine. After providing an overview of the historical use of gold and gold compounds, the technique of implanting this noble metal is introduced. The reasons for establishing the terms gold acupuncture and gold (bead) implantation are described, considering the question whether and what kind of methodological differences exist behind these terms. Next, previous publications concerning the effects of gold implantation in tissue are summarised. In 2002 it was proven that gold ions are released from the surface of gold implants by a process termed dissolucytosis. Subsequent publications further investigated details about the interaction between gold ions and tissue as well as the distribution pattern of bio-released ions. Gold compounds were previously used for chrysotherapy in human medicine until medication with fewer side effects became established. The anti-inflammatory and immuno-modulatory properties of gold compounds were used to treat rheumatoid arthritis. Current research aims to ascertain whether the anti-inflammatory and immuno-modulating effects of gold compounds are imitated by gold ions released from gold implants at a local level. In conclusion, the present review summarises important findings about the effects of gold implanted in tissue. However, further research is necessary to estimate the limitations and benefits of this auromedication.

  12. Subject-specific hip geometry and hip joint centre location affects calculated contact forces at the hip during gait.

    PubMed

    Lenaerts, G; Bartels, W; Gelaude, F; Mulier, M; Spaepen, A; Van der Perre, G; Jonkers, I

    2009-06-19

    Hip loading affects the development of hip osteoarthritis, bone remodelling and osseointegration of implants. In this study, we analyzed the effect of subject-specific modelling of hip geometry and hip joint centre (HJC) location on the quantification of hip joint moments, muscle moments and hip contact forces during gait, using musculoskeletal modelling, inverse dynamic analysis and static optimization. For 10 subjects, hip joint moments, muscle moments and hip loading in terms of magnitude and orientation were quantified using three different model types, each including a different amount of subject-specific detail: (1) a generic scaled musculoskeletal model, (2) a generic scaled musculoskeletal model with subject-specific hip geometry (femoral anteversion, neck-length and neck-shaft angle) and (3) a generic scaled musculoskeletal model with subject-specific hip geometry including HJC location. Subject-specific geometry and HJC location were derived from CT. Significant differences were found between the three model types in HJC location, hip flexion-extension moment and inclination angle of the total contact force in the frontal plane. No model agreement was found between the three model types for the calculation of contact forces in terms of magnitude and orientations, and muscle moments. Therefore, we suggest that personalized models with individualized hip joint geometry and HJC location should be used for the quantification of hip loading. For biomechanical analyses aiming to understand modified hip joint loading, and planning hip surgery in patients with osteoarthritis, the amount of subject-specific detail, related to bone geometry and joint centre location in the musculoskeletal models used, needs to be considered.

  13. Psoas impingement syndrome in hip osteoarthritis.

    PubMed

    Di Lorenzo, Luigi; Jennifer, Yanow; Pappagallo, Marco

    2009-01-01

    The degenerative processes underlying osteoarthritis of the hip produce both anatomical and biomechanical changes in and around the involved joint. A good understanding of hip anatomy and the forces crossing the hip joint is essential to understand both hip pathology and current treatment techniques. Total hip arthroplasty (THA) has become a mainstay of treatment for advanced osteoarthritis of the hip. Several factors contribute to post-operative hip pain in THA patients. Iliopsoas impingement on the prosthetic cup after total hip replacement is one of the causes of pain following hip surgery, often due to an anterior overlap of the implant with respect to the acetabulum. The anatomic shape of the anterior acetabular ridge, which may be straight or curved, influences this overlap. In this paper we present a case illustrating a psoas impingement-like syndrome in a patient with severe hip osteoarthritis who has not undergone hip replacement surgery. We discuss the compensatory strategies employed by the patient to reduce pain and prevent falls, and show CT scan images depicting the underlying anatomic pathology.

  14. Review on squeaking hips

    PubMed Central

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-01-01

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  15. Results of total hip arthroplasty using a bionic hip stem.

    PubMed

    Fokter, Samo K; Sarler, Taras; Strahovnik, Andrej; Repše-Fokter, Alenka

    2015-06-01

    The trabecular-orientated bionic hip stem was designed to mimic the natural force transmission through the femur in total hip arthroplasty, resulting in supposedly longer prosthesis survivability. The aim of this study was to compare the second-generation bionic hip stem to a standard uncemented hip stem. A group of 18 patients (21 hips) who underwent total hip arthroplasty with a bionic stem (bionic group) was compared with a historic group of 12 patients (12 hips) treated with standard anatomic hip stem (control group). During the first year after the procedure, the densitometric measurements of the bone around the prosthesis were taken. Radiographic and clinical assessments were additionally performed preoperatively and at the three month, six month, one year and three year follow-ups in the bionic group. In the bionic group, one patient was revised for aseptic loosening and 16 patients (19 hips) were available to the final follow-up. A significant decrease of bone mineral density was found in Gruen zones 3, 4 and 5 in the bionic group, and in zone 7 in both groups. The bionic group had a significantly higher bone mineral density in Gruen zone 1 at the one year follow-up. At the final follow-up, all prostheses were radiologically stable in both groups. Provided that a good implant position is achieved, comparable short-term results can be obtained using a bionic stem. Still, a decrease of bone mineral density in Gruen zone 7 occurred in both groups. Further studies are required to determine survivability of the bionic stem.

  16. Two-stage Revision for Periprosthetic Hip and Knee Joint Infections

    PubMed Central

    Kini, Sunil Gurpur; Gabr, Ayman; Das, Rishi; Sukeik, Mohamed; Haddad, Fares Sami

    2016-01-01

    Background: Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following hip and knee surgery. The diagnostic workflow of PJI includes detailed clinical examination, serum markers, imaging and aspiration/biopsy of the affected joint. The goals of treatment are eradication of the infection, alleviation of pain, and restoration of joint function. Surgical management of PJI consists of debridement, antibiotics and implant retention (DAIR) and single or two-stage revision procedures. Two-stage revision remains the gold standard for treatment of PJIs. We aim to discuss the two stage procedure in this article and report the outcomes. Methods: The first stage of the two stages consists of removal of all components and associated cement with aggressive debridement and placement of an antibiotic-loaded cement spacer. Patients are then treated with variable periods of parenteral antibiotics, followed by an antibiotic free period to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest infection control, then the second stage can be undertaken and this involves removal of the cement spacer, repeat debridement, and placement of a new prosthesis. Results: Common themes around the two-stage revision procedure include timing of the second stage, antibiotics used in the interim period, length of the interim period before consideration of reimplantation and close liaising with microbiologists. Conclusion: Successful eradication of infection and good functional outcome using the two stage procedure is dependent on a multidisciplinary approach and having a standard reproducible startegy. PMID:28144371

  17. Two-stage Revision for Periprosthetic Hip and Knee Joint Infections.

    PubMed

    Kini, Sunil Gurpur; Gabr, Ayman; Das, Rishi; Sukeik, Mohamed; Haddad, Fares Sami

    2016-01-01

    Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following hip and knee surgery. The diagnostic workflow of PJI includes detailed clinical examination, serum markers, imaging and aspiration/biopsy of the affected joint. The goals of treatment are eradication of the infection, alleviation of pain, and restoration of joint function. Surgical management of PJI consists of debridement, antibiotics and implant retention (DAIR) and single or two-stage revision procedures. Two-stage revision remains the gold standard for treatment of PJIs. We aim to discuss the two stage procedure in this article and report the outcomes. The first stage of the two stages consists of removal of all components and associated cement with aggressive debridement and placement of an antibiotic-loaded cement spacer. Patients are then treated with variable periods of parenteral antibiotics, followed by an antibiotic free period to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest infection control, then the second stage can be undertaken and this involves removal of the cement spacer, repeat debridement, and placement of a new prosthesis. Common themes around the two-stage revision procedure include timing of the second stage, antibiotics used in the interim period, length of the interim period before consideration of reimplantation and close liaising with microbiologists. Successful eradication of infection and good functional outcome using the two stage procedure is dependent on a multidisciplinary approach and having a standard reproducible startegy.

  18. Hip arthroscopy

    MedlinePlus

    Johnson D, Weiss WM. Basic arthroscopic principles. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ... 11. Sanchez VMI, Meza AO. Hip arthroscopy. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ...

  19. Conus hip prosthesis.

    PubMed

    Wagner, H; Wagner, M

    2001-01-01

    50 years ago, prosthetic replacement of the hip joint ushered in a new epoch in orthopaedics. Total hip replacement made it possible to remove a severely diseased, painful hip and restore normal function and a normal quality of life to the afflicted patient. The early results of total hip replacement are almost all spectacular and hip replacement has become the most successful type of orthopaedic surgery. These good results using an approach that was technically relatively simple resulted in a temptation to implant prosthetic hip joints with ever increasing frequency in ever younger patients. This led to the emergence of new problems, which were not so clearly recognised at the outset: it emerged that the stability of prosthetic hip joints was of limited duration. This had the following consequence: If a total hip prosthesis is implanted in an elderly person whose remaining life-expectancy is shorter than the longevity of the prosthesis, hip replacement is a life-long solution. We can therefore say that, for a patient who has only 10 to 15 years left to live, their hip problem is solved by total hip replacement. For young people, who still have a long life expectancy in front of them, it is different. They will experience failure of the artificial joint and require further surgery. The commonest and most important type of failure in total hip prostheses is aseptic loosening, which is associated with resorption of bone at the site of the prosthesis. The cause of this phenomenon has only gradually been recognised in the course of the years. Initially, the unanimous opinion was that the methacrylate cement, used to fix the components of the prosthesis in the bone, was the definitive cause of aseptic loosening because fissures and fractures of the cement were almost always found during surgical revision of loosened joints. There was talk of "cement disease" and great efforts were made to improve the quality of the cement and the cementing technique. Moreover, even

  20. 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

  1. Recent patents and designs on hip replacement prostheses.

    PubMed

    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.

  2. Biotribology of artificial hip joints

    PubMed Central

    Di Puccio, Francesca; Mattei, Lorenza

    2015-01-01

    Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213

  3. Randomized trial of spacers in asthma.

    PubMed

    Dahiya, Baljit; Mathew, Joseph L; Singh, Meenu

    2007-07-01

    To compare the efficacy of all types of spacers commonly available to children in India. 150 children 5-14 yr of age with persistent asthma presenting with peak expiratory flow (PEF) < 70% of personal best were randomized to receive 200 mg salbutamol through one of five spacers: A) 750 ml spacer with valve, B) 165 ml spacer with valve, C) 250 ml spacer without valve, D) 1000 ml indigenously made spacer without valve and E) 500 ml indigenously made spacer without valve. PEF measurement was repeated 15 minutes later. Children> 8 yr old performed spirometry in addition to PEF. Absolute change and percentage improvement of PEF and FEV1 were compared among the groups. Subjects in all groups had comparable baseline demographic characteristics and PEF. All showed significant improvement in PEF and FEV1 over baseline values. The change in PEF and percentage improvement were comparable among all five groups (p=0.780 and p=0.955 respectively). Likewise change in FEV1 and percentage improvement were also comparable. The five groups showed no difference in efficacy, irrespective of severity of baseline airway obstruction. The five spacers were equally efficacious for the delivery of bronchodilator in children with moderate persistent asthma presenting with airway obstruction.

  4. [Correction of lower eyelid retraction with a porous polyethylene (Medpor) lower eyelid spacer--Medpor spacer in lower eyelid retraction].

    PubMed

    de Jong-Hesse, Y; Paridaens, D A

    2006-07-01

    The correction of lower eyelid retraction remains a challenge with established techniques having disadvantages. A recently described alternative is implantation of an ultrathin high density porous polyethylene lower eyelid spacer (Medpor LES). We report our experience on implanting this Medpor LES, especially in patients with lower eyelid retraction due to Graves' orbitopathy. All patients receiving a Medpor LES between March 2003 and November 2004 in the Rotterdam Eye Hospital were included. Indications and preceding procedures as well as the degree of proptosis were noted. Preoperative and postoperative lower eyelid retraction were compared by measuring scleral show inferior to the limbus (LSS). Postoperative complications, recurrent retraction and secondary surgical procedures were recorded. Out of 12 patients (16 eyelids) in whom a Medpor LES was inserted 8 patients suffered from Graves' orbitopathy. Mean follow-up was 7.5 months (range 4 - 11 months). Final cosmetic outcome was good in 8/16 eyelids and improved in 7/16 eyelids. Lower eyelid retraction (LSS) was reduced significantly (1.34 mm +/- 0.214 (mean +/- std. error of mean), p = 0.004). Complications included eyelid contour deformity (4/16 eyelids), remaining irritation of the eye (1/16) and problems in down gaze (4/16) as well as recurrent lower eyelid retraction (2/16) requiring further surgery in 3 of 11 patients. In selected patients, insertion of a Medpor lower eyelid spacer may be a good alternative to correct lower eyelid retraction.

  5. Survival analysis of the Wallis interspinous spacer used as an augment to lumbar decompression.

    PubMed

    Nicholson, Jamie A; Scott, Chloe E H; Duckworth, Andrew D; Burke, John G; Gibson, John N Alastair

    2017-07-08

    The Wallis fixed interspinous spacer may augment traditional decompression in the treatment of lumbar spinal stenosis. The aim of this study was to determine factors influencing survival of the Wallis interspinous spacer and to identify specific modes and predictors of failure. We performed a retrospective cohort study of 244 Wallis interspinous spacers implanted in 195 consecutive patients with a mean age of 56 years (range 21-87) to augment single or multi-level decompression. We examined patient demographics, indications for surgery, surgical techniques and pathology on magnetic resonance imaging (MRI). A Kaplan-Meier survival analysis was performed. Median follow-up was 4.5 years (range 2-8). Sixteen patients were lost to follow-up. Repeat MRI was performed in 98 patients (50%). A recurrent stenosis was found in 21% of patients (41/195) and occurred at a similar incidence at the level of the spacer and at adjacent spinal levels. Revision decompression was performed in 19 patients (10%) at 2.8 ± 1.8 years (range 6 months-6 years) with implant removal in 15 and conversion to fusion in 4 patients. No specific patient factors or pre-operative MRI findings predicted failure. Five-year survival was 91% (95% CI: 79-96%). The Wallis implant is generally implanted without complication when used as an adjunct to decompression with a good medium term survival. Though disc heights were maintained, the Wallis spacer did not however appear to reduce the incidence of recurrent spinal or foraminal stenosis from that expected from decompression alone.

  6. Unsatisfactory surgical learning curve with hip resurfacing.

    PubMed

    Berend, Keith R; Lombardi, Adolph V; Adams, Joanne B; Sneller, Michael A

    2011-05-01

    Hip resurfacing is considered by many to be a conservative alternative to conventional total hip arthroplasty. There are advantages and drawbacks to any procedure, and there is a learning curve associated with the introduction of any new technology. The purpose of this study is to report the complication rate, types of complications, and outcomes of hip resurfacing during the early experience of two high-volume hip surgeons. Seventy-three hip resurfacing procedures were performed in sixty-four patients between September 2006 and March 2009. These procedures represented 6% of all of the primary hip arthroplasty procedures performed by the two surgeons. After an average duration of follow-up of twenty-five months, there were six revisions--i.e., an early failure rate of 8%. These revisions were performed to treat two deep infections, two femoral neck fractures, one case of femoral implant loosening, and one failure of an acetabular implant. Because of a high early failure rate, we have reduced the utilization of hip resurfacing in our patients who are candidates for hip arthroplasty.

  7. Postfusion magnetic resonance imaging artifacts caused by a titanium, cobalt-chromium-molybdenum, and carbon intervertebral disc spacer.

    PubMed

    Ernstberger, Thorsten; Heidrich, Gabert

    2007-04-01

    Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium and CoCrMo-alloys or carbon fiber reinforced polymers (CFRP). Implant-related susceptibility artifacts can decrease the quality of magnetic resonance imaging (MRI) scans. This cadaveric study aimed to demonstrate the extent that implant-related MRI artifacting affects the postfusion differentiation of the spinal canal (SC) and intervertebral disc space (IDS). In 6 cadaveric porcine spines, we evaluated the postimplantation MRI scans of a titanium, CoCrMo-spacer and CFRP-spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into regions of interest (ROI) to characterize the SC and IDS. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists artifact-affected image quality of the median MRI slice was rated on a score of 0-1-2-3. A maximum score of 15 points for the SC and 9 points for the IDS (100%) was possible. Turbo spin echo sequences produced the best scores for both spacers and the control. Only the control achieved a score of 100%. For the IDS the CoCrMo-spacer, titanium and CFRP-spacer maximally scored 0%, 0% and 74%, for the SC 60%, 80% and 99%, respectively. By using favored T1 TSE sequences the CFRP-spacer represented clear advantages in postfusion spinal imaging. Independent of artifact dimensions the used scoring system allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control.

  8. LISA telescope spacer design investigations

    NASA Astrophysics Data System (ADS)

    Sanjuan, Josep; Mueller, Guido; Livas, Jeffrey; Preston, Alix; Arsenovic, Petar; Castellucci, Kevin; Generie, Joseph; Howard, Joseph; Stebbins, Robin

    ) and materials such as Silicon Carbide (SiC) and Carbon Fiber Reinforced Plastic (CFRP) are considered to be used in the telescope spacer structure. We will describe our experimental efforts to understand and quantify the behavior of different materials and also discuss a first investigation of a specific on-axis SiC telescope spacer for LISA. This work is supported by NASA contract 00069955.

  9. An Assessment of Gender-Specific Risk of Implant Revision After Primary Total Hip Arthroplasty: A Systematic Review and Meta-analysis.

    PubMed

    Towle, Kevin M; Monnot, Andrew D

    2016-12-01

    Total hip arthroplasty (THA) has been a successful reconstructive procedure to mitigate pain associated with diseases of the hip joint. However, some THA procedures require revision due to mechanical or biological failure. The purpose of this study was to synthesize and examine the evidence on the relative risk of revision in men and women after primary THA procedures. We conducted a systematic literature review of cohort studies reporting THA revision risk estimate by gender. Study quality scoring and a random effects meta-analysis were performed to estimate the meta-relative risk (meta-RR) and corresponding 95% confidence interval (95% CI) of revision, comparing men to women. Males had a statistically significant increased risk of revision after primary THA (meta-RR = 1.33 [95% CI: 1.13-1.57]), when compared to females. When stratified by cause of revision, males had a statistically significant increased risk of revision due to any cause (meta-RR = 1.16 [95% CI: 1.01-1.33]), aseptic loosening (meta-RR = 1.54 [95% CI: 1.05-2.25]), and infection (meta-RR = 1.55 [95% CI: 1.11-2.15]). For primary THA operations performed during the 2000s, males in Europe had a statistically significant increased risk of revision (meta-RR 1.42 [95% CI: 1.25-1.61]) while males in the United States had a statistically significant decreased risk of revision (meta-RR 0.80 [95% CI: 0.72-0.89]). These results provide evidence for an increased risk of revision after THA among males, which may be impacted by geographic location and time period of operation. Findings suggest that a better understanding of the underlying drivers of gender-specific risks would help reduce postsurgery complications. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Cementless Total Hip Arthroplasty Involving Trochanteric Osteotomy without Subtrochanteric Shortening for High Hip Dislocation

    PubMed Central

    Lee, Soong Joon; Kim, Hee Joong

    2017-01-01

    Background Total hip arthroplasty with subtrochanteric shortening osteotomy is widely performed for high hip dislocation. However, suboptimal leg length discrepancy correction and nonunion of the osteotomy site remain concerns. Although total hip arthroplasty using trochanteric osteotomy without subtrochanteric osteotomy was introduced, cemented implants have been more commonly used than contemporary cementless implants in this procedure. We evaluated the long-term results of cementless total hip arthroplasty with trochanteric osteotomy without subtrochanteric osteotomy for high hip dislocation. Methods From 1990 to 2002, 27 cementless total hip arthroplasties using trochanteric osteotomy without subtrochanteric osteotomy were performed in 26 patients with Crowe III or IV high hip dislocation and a mean age of 36.4 ± 12.9 years. Seven ceramic-on-ceramic, 8 ceramic-on-polyethylene, 10 metal-on-polyethylene, and 2 metal-on-metal bearings were inserted. Mean follow-up was 15.1 ± 3.7 years. We retrospectively reviewed medical records and radiographic data and evaluated the clinical and radiological results including the Harris hip score, implant survival, correction of leg length discrepancy, and occurrence of complications. Results The mean Harris hip score and leg length discrepancy improved significantly from 73.3 to 94.9 points and from 4.3 cm to 1.0 cm, respectively. With revision for loosening set as the end point, implant survival rates at 10 and 15 years postoperatively were 96.0% and 90.9% for stems and 74.1% and 52.3% for cups. In 8 of 10 hips with the metal-on-polyethylene bearing and 4 of 8 hips with the ceramic-on-polyethylene bearing, revision surgery was performed for aseptic loosening. However, no revision was performed in hips with the ceramic-on-ceramic bearing or the metal-on-metal bearing. Implant survival was significantly different by the type of bearing surface. Two permanent neurologic complications occurred in patients with a limb lengthening

  11. NEW BEARING SURFACES IN TOTAL HIP REPLACEMENT

    PubMed Central

    Schwartsmann, Carlos Roberto; Boschin, Leonardo Carbonera; Gonçalves, Ramiro Zilles; Yépez, Anthony Kerbes; de Freitas Spinelli, Leandro

    2015-01-01

    Total hip arthroplasty is being increasingly indicated for younger and more active patients, in addition to a naturally growing demand for the procedure because of increasing life expectancy among patients. The high costs of this surgery and the controversies regarding implant performance have made this topic the subject of constant research, seeking new materials with better resistance to wear and better biocompatibility. The present article provides a review of new surfaces in total hip arthroplasty. PMID:27042614

  12. Evaluation of the hip center in total hip arthroplasty for old developmental dysplasia.

    PubMed

    Flecher, Xavier; Parratte, Sebastien; Brassart, Nicolas; Aubaniac, Jean-Manuel; Argenson, Jean-Noël

    2008-12-01

    We describe the problems with positioning the hip center according to the severity of dislocation in 97 cementless total hip arthroplasty for developmental dysplasia of the hip. The mean location of the hip center from the interteardrop was 30.4 +/- 8.7 mm horizontally and 23.4 +/- 5.4 mm vertically. The presence of a limp correlated with a superior placement of the cup. Four cups were revised, 2 of which with a significant high hip center. The survival rate of the acetabular component was 95% at 12 years. Craniopodal repositioning was easy in class 1. In class 2, the cup was the largest. In class 3, the greatest variations of the hip center were found. In class 4, the smallest implants were necessary for positioning in the true acetabulum.

  13. Developing a sustainable hip service in Cambodia.

    PubMed

    Holt, Jacquelyn A; Aird, James J; Gollogly, James G; Ngiep, Ou C; Gollogly, Sohrab

    2014-01-01

    Initial report on establishment of a hip service in Phnom Penh, Cambodia at Children's Surgical Centre. We describe indications for total hip replacement (THR) and initial results. A database was established to collect data and track patients for follow up. Initial data collected included; diagnosis, implant used, post-operative complications. As the service developed, pre- and postoperative Harris hip scores were included. High rate of avascular necrosis (AVN) as the initial diagnosis. Five years post initiation of the hip service, 95 patients have received 116 THRs; including 10 revisions, 12 bilateral procedures. Complications/failures requiring revision involved four prosthetic femoral neck fractures, two aseptic acetabular component, two late infections, one instability. One failure, a periprosthetic acetabular fracture, required removal of all prosthetics. Complications not requiring revision, included three post-op foot drops, three superficial wound infections, one Vancouver B1 periprosthetic femur fracture. Average age was 41. Overall implant survival is 85% at three years. AVN was the most common indication for THR: many patients had a history of hip trauma, and/or prolonged steroids from traditional healers for pain. Problems with specific implants were addressed by the company. A different stem is now routinely used, no further fractures have been reported. Acetabular loosening, thought to be due to poor technique, has been addressed by focused training. Infection rate is monitored, and microbiology resources are improving. Developing an affordable hip arthroplasty service in a country like Cambodia is challenging. Developing a local registry has helped to identify complications and modify techniques.

  14. International variation in hip replacement rates

    PubMed Central

    Merx, H; Dreinhofer, K; Schrader, P; Sturmer, T; Puhl, W; Gunther, K; Brenner, H

    2003-01-01

    Objectives: To summarise epidemiological data on the frequency of hip replacements in the countries of the developed world, especially in countries of the Organisation for Economic Cooperation and Development (OECD), and to investigate whether missing consensus criteria for the indication for total hip replacement (THR) result in different replacement rates. Methods: Country-specific hip replacement rates were collected using the available literature, different data sources of national authorities, and estimates of leading hip replacement manufacturers. Results: According to administrative and literature data sources the reported crude primary THR rate varied between 50 and 130 procedures/100 000 inhabitants in OECD countries in the 1990s. The crude overall hip implantation rate, summarising THR, partial hip replacement, and hip revision procedures, was reported to range from 60 to 200 procedures/100 000 inhabitants in the late 1990s. Moreover, large national differences were seen in the relationship between total and partial hip replacement procedures. Conclusion: The reported differences in hip replacement rates in OECD countries are substantial. They may be due to various causes, including different coding systems, country-specific differences in the healthcare system, in total expenditure on health per capita, in the population age structure, and in different indication criteria for THR. PMID:12594106

  15. The effect of metal artefact reduction on CT-based attenuation correction for PET imaging in the vicinity of metallic hip implants: A phantom study

    PubMed Central

    Harnish, Roy; Prevrhal, Sven; Alavi, Abass; Zaidi, Habib; Lang, Thomas

    2014-01-01

    Background To determine if metal artefact reduction (MAR) combined with a priori knowledge of prosthesis material composition can be applied to obtain CT-based attenuation maps with sufficient accuracy for quantitative assessment of 18F-fluorodeoxyglucose uptake in lesions near metallic prostheses. Methods A custom hip prosthesis phantom with a lesion-sized cavity filled with 0.2 ml 18F-FDG solution having an activity of 3.367 MBq adjacent to a prosthesis bore was imaged twice with a chrome-cobalt steel hip prosthesis and a plastic replica, respectively. Scanning was performed on a clinical hybrid PET/CT system equipped with an additional external 137Cs transmission source. PET emission images were reconstructed from both phantom configurations with CT-based attenuation correction (CTAC) and with CT-based attenuation correction using MAR (MARCTAC). To compare results with the attenuation-correction method extant prior to the advent of PET/CT, we also carried out attenuation correction with 137Cs transmission-based attenuation correction (TXAC). CTAC and MARCTAC images were scaled to attenuation coefficients at 511 keV using a tri-linear function that mapped the highest CT values to the prosthesis alloy attenuation coefficient. Accuracy and spatial distribution of the lesion activity was compared between the three reconstruction schemes. Results Compared to the reference activity of 3.37 MBq, the estimated activity quantified from the PET image corrected by TXAC was 3.41 MBq. The activity estimated from PET images corrected by MARCTAC was similar in accuracy at 3.32 MBq. CTAC corrected PET images resulted in nearly 40% overestimation of lesion activity at 4.70 MBq. Comparison of PET images obtained with the plastic and metal prostheses in place showed that CTAC resulted in a marked distortion of the 18F-FDG distribution within the lesion, whereas application of MARCTAC and TXAC resulted in lesion distributions similar to those observed with the plastic replica

  16. Posterior Arch Augmentation (Spinoplasty) before and after Single and Double Interspinous Spacer Introduction at the Same Level: Preventing and Treating the Failure?

    PubMed

    Manfré, Luigi

    2014-10-31

    Lumbar spinal canal stenosis (LSCS) is one of the most common degenerative diseases in elderly patients. Failure of he treatment can occur, generally related to bone remodelling/fracture of spinous processes. PMMA augmentation of the posterior arch (spinoplasty, SP) has recently been proposed in case of neoplastic involvement. This study evaluated the efficacy of SP as a prophylactic treatment before introducing an interspinous spacer (IS). Moreover, we consider the possibility to treat patients who previously underwent IS implants with subsequent failure of the device, by introducing a second spacer at the same level, performing accessory SP. From January 2009 to September 2011, 174 patients with LSCS underwent CT-guided percutaneous IS implant in our department. From January 2011, all patients with osteoporosis underwent prophylactic SP before introducing the spacer. Moreover, in patients with re-stenosis related to bone remodelling and/or fracture, after strengthening the spinous processes with PMMA introduction, a second similar device was introduced to re-open the stenotic spinal canal. In patients with prophylactic treatment before spacer introduction, no restenosis occurred at three to 12 month follow-up. Patients who underwent second spacer implant at the same level after posterior arch augmentation again obtained a resolution of symptoms, and no further bone remodelling had occurred at follow-up controls. In conclusion, prophylactic SP prevents single spacer failure for bone remodelling/fracture, and allows failure repair by introducing a second spacer at the same level.

  17. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.

    PubMed

    Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberdörster, Günter

    2015-07-01

    The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Pyrocarbon spacer as a trapezium replacement for arthritis of the trapeziometacarpal joint; a follow-up study of 60 cases.

    PubMed

    Szalay, Gabor; Meyer, Christof; Scheufens, Tanja; Schnettler, Reinhard; Christ, Ralph; Schleicher, Iris

    2013-12-01

    Rhizarthrosis is the most common degenerative joint disease of the hand, affecting about 10% of the population. We report our results with trapezium replacement using a pyrocarbon spacer. Between January 2005 and April 2010, 70 patients underwent trapeziectomy with interposition of a pyrocarbon spacer. Sixty patients were examined at an average follow-up of 23.6 (5-64) months after the operation. Six (8.6%) of the 70 implanted pyrocarbon spacers dislocated. Based on the assessment scale devised by Buck-Gramcko, 19 patients achieved a very good outcome (31.6%), 31 patients (51.6%) had a good outcome, six results were satisfactory (10%) and four patients (6.6%) had a poor result. In this study, trapeziectomy and implantation of a pyrocarbon spacer achieved good or very good results in 83.2% of cases. The high cost of the implant and the observed rate of spacer dislocation should however be considered critically. While the short-term results of this method are encouraging, long-term outcomes will show whether this technique can keep up with the good results of suspension arthroplasty.

  19. Cervical interfacet spacers and maintenance of cervical lordosis.

    PubMed

    Tan, Lee A; Straus, David C; Traynelis, Vincent C

    2015-05-01

    OBJECT The cervical interfacet spacer (CIS) is a relatively new technology that can increase foraminal height and area by facet distraction. These offer the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion potential due to the relatively large osteoconductive surface area and compressive forces exerted on the grafts. These potential benefits, along with the relative ease of implantation during posterior cervical fusion procedures, make the CIS an attractive adjuvant in the management of cervical pathology. One concern with the use of interfacet spacers is the theoretical risk of inducing iatrogenic kyphosis. This work tests the hypothesis that interfacet spacers are associated with loss of cervical lordosis. METHODS Records from patients undergoing posterior cervical fusion at Rush University Medical Center between March 2011 and December 2012 were reviewed. The FacetLift CISs were used in all patients. Preoperative and postoperative radiographic data were reviewed and the Ishihara indices and cervical lordotic angles were measured and recorded. Statistical analyses were performed using STATA software. RESULTS A total of 64 patients were identified in whom 154 cervical levels were implanted with machined allograft interfacet spacers. Of these, 15 patients underwent anterior-posterior fusions, 4 underwent anterior-posterior-anterior fusions, and the remaining 45 patients underwent posterior-only fusions. In the 45 patients with posterior-only fusions, a total of 110 levels were treated with spacers. There were 14 patients (31%) with a single level treated, 16 patients (36%) with two levels treated, 5 patients (11%) with three levels treated, 5 patients (11%) with four levels treated, 1 patient (2%) with five levels treated, and 4 patients (9%) with six levels treated. Complete radiographic data were available in 38 of 45 patients (84%). On average, radiographic follow-up was obtained at 256.9 days (range 48-524 days

  20. Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants.

    PubMed

    Varano, R; Bobyn, J D; Medley, J B; Yue, S

    2006-02-01

    The microstructure and its effect on the friction behavior of a medical grade wrought cobalt-chromium-molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed-packed (HCP) phase due to a strain-induced transformation (SIT) from the metastable face-centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics. Copyright 2005 Wiley Periodicals, Inc.

  1. Results of hip resurfacing

    PubMed Central

    Favetti, Fabio; Casella, Filippo; Papalia, Matteo; Panegrossi, Gabriele

    2011-01-01

    Background The renewed popularity of resurfacing hip arthroplasty in the last 10 years has generated a remarkable quantity of scientific contributions based on mid- and short-term follow-up. More than one paper has reported a consistent early revision rate as a consequence of biological or biomechanical failure. Two major complications are commonly described with resurfacing implants: avascular necrosis and femoral-neck fracture. A close relationship between these two events has been suggested, but not firmly demonstrated, whereas cementing technique seems to be better understood as potential cause of failure. Methods We performed an in vitro study in which four different resurfacing implants were evaluated with a simulated femoral head, two types of cement, (low and high viscosity) and two cementing techniques: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). Results High-viscosity cement showed homogeneous distribution over the entire femoral head. Low-viscosity cement showed a massive polar concentration with insufficient, if not absent, distribution in the equatorial zone. Conclusion Polar cement concentration could be a risk factor for early implant failure due to two effects on the femoral head: biological (excessive local exothermic reaction could cause osteocyte necrosis) and biomechanical (which could lead to uneven load distribution on the femoral head). PMID:21234563

  2. The Effect of Subluxation of Articulating Antibiotic Spacers on Bone Defects and Degree of Constraint in Revision Knee Arthroplasty.

    PubMed

    Lau, Adrian C K; Howard, James L; Macdonald, Steven J; Teeter, Matthew G; Lanting, Brent A

    2016-01-01

    This study investigated whether subluxation of articulating antibiotic spacers is associated with the bone defects found and constraint required when re-implanting the knee arthroplasty components. Staged revisions for infections of primary total knee arthroplasties between 2004 and 2012 were examined. Radiographic sagittal and coronal subluxations of 72 knees were measured prior to second stage revision. Coronal subluxation was found to be associated with increased requirement for constrained knee systems (P<0.035). Sagittal subluxation was associated with greater tibia bone defects (P<0.037). Careful surgical technique and monitoring of articulating spacers should be done to avoid subluxation after stage 1 revision. If subluxation of the articulating spacer is present, constrained revision knee systems as well as augments should be available at time of re-implantation.

  3. A finite element study on the mechanical response of the head-neck interface of hip implants under realistic forces and moments of daily activities: Part 2.

    PubMed

    Fallahnezhad, Khosro; Farhoudi, Hamidreza; Oskouei, Reza H; Taylor, Mark

    2017-09-07

    A finite element model was developed to investigate the effect of loading regimes caused by various daily activities on the mechanical behaviour of the head-neck taper junction in modular hip replacements. The activities included stair up, stair down, sit to stand, stand to sit, one leg standing and knee bending. To present the real mechanical environment of the junction, in addition to the force components, the frictional moments produced by the frictional sliding of the head and cup were applied to a CoCr/CoCr junction having a 12/14 taper with a proximal mismatch angle of 0.024°. This study revealed that stair up with the highest fretting work per unit of length (1.62 × 10(4)J/m) was the most critical activity, while knee bending and stand to sit with 1.96 × 10(3)J/m were the least critical activities. For all the activities, the superolateral region of the neck was identified as the most critical region in terms of having larger values of fretting work per unit of area. This study showed also that the relative micro-motions and contact stresses occurring at the head-neck interface for all the studied activities are mostly in the range of 0-38µm and 0-350MPa, respectively. These ranges may be accordingly employed for conducting relevant in-vitro tests to more realistically represent the mechanical environment of taper junctions with the same materials and geometry studied in this work. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Metal ion concentrations and semen quality in patients undergoing hip arthroplasty: A prospective comparison between metal-on-metal and metal-on-polyethylene implants.

    PubMed

    Chen, Szu-Yuan; Chang, Chih-Hsiang; Hu, Chih-Chien; Chen, Chun-Chieh; Chang, Yu-Han; Hsieh, Pang-Hsin

    2016-03-01

    The widespread usage of metal-on-metal (MoM) articulations in total hip arthroplasty (THA) has been tempered by concerns of increased metal ion production. The purpose of the study is to evaluate the influence of metal ion exposure on semen quality in young male patients undergoing THA. Male patients who were scheduled for unilateral THA and aged between 20 and 45 years were prospectively enrolled. Patients were sorted into MoM and metal-on-polyethylene (MoP) groups with equal case number. Semen and blood metal ion levels were measured and sperm analysis was performed before, 6 months after, and 1 year after surgery. Compared to preoperative baseline, patients (n = 50) in both groups had increased cobalt (Co) and chromium (Cr) concentrations in blood and seminal fluid after surgery. Between-group comparisons at 6 months and 1 year after surgery showed that patients in the MoM group both had a greater Co concentration in blood and semen and a greater Cr concentration in blood and semen. Patients receiving MoM prosthesis had a reduced percentage of morphologically normal sperm, and decreases from the preoperative level (44.7%) were significant at 6 months (36.8%, p = 0.03) and 1 year (33.8%, p = 0.004). Our data shows a significantly greater concentration of metal ion in blood and semen in patients with MoM prosthesis with a reduced percentage of morphologically normal sperm. Despite small effects on sperm quality, some concerns remain. Further studies are necessary to determine sources of metal ion and to investigate effects on male fertility. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  5. Design parameters and the material coupling are decisive for the micromotion magnitude at the stem-neck interface of bi-modular hip implants.

    PubMed

    Jauch, S Y; Huber, G; Haschke, H; Sellenschloh, K; Morlock, M M

    2014-03-01

    Several bi-modular hip prostheses exhibit an elevated number of fretting-related postoperative complications most probably caused by excessive micromotions at taper connections. This study investigated micromotions at the stem-neck interface of two different designs: one design (Metha, Aesculap AG) has demonstrated a substantial number of in vivo neck fractures for Ti-Ti couplings, but there are no documented fractures for Ti-CoCr couplings. Conversely, for a comparable design (H-Max M, Limacorporate) with a Ti-Ti coupling only one clinical failure has been reported. Prostheses were mechanically tested and the micromotions were recorded using a contactless measurement system. For Ti-Ti couplings, the Metha prosthesis showed a trend towards higher micromotions compared to the H-Max M (6.5 ± 1.6 μm vs. 3.6 ± 1.5 μm, p=0.08). Independent of the design, prostheses with Ti neck adapter caused significantly higher interface micromotions than those with CoCr ones (5.1 ± 2.1 μm vs. 0.8 ± 1.6 μm, p=0.001). No differences in micromotions between the Metha prosthesis with CoCr neck and the H-Max M with Ti neck were observed (2.6 ± 2.0 μm, p=0.25). The material coupling and the design are both crucial for the micromotions magnitude. The extent of micromotions seems to correspond to the number of clinically observed fractures and confirm the relationship between those and the occurrence of fretting corrosion. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. Total Hip Arthroplasty in a Girdlestone Hip following a Failed Hemiarthroplasty

    PubMed Central

    Purushotham, VJ; Ranganath, BT

    2015-01-01

    Introduction: Girdlestone hip arthroplasty, though described as a salvage procedure for infected hip joints, can also be considered for failed Hemiarthroplasty procedures. The functional results of such Girdlestone hip may not be satisfactory. They may require total hip replacement to improve the quality of life, which are technically challenging. Here we are reporting such a case ina 60 year old male patient, with review of literature. Case Report: A 60 year old male patient underwent cemented bipolar hemiarthroplasty for fracture neck of femur which failed, owing to improper implantation. Subsequently he underwent Girdlestone arthroplasty which resulted in persistent painful hip. He presented to us in this situation, where we successfully converted the Girdlestone arthroplasty to a Total Hip arthroplasty. Conclusion: Improper implantation in Hemiarthroplasty fails subsequently. In such cases Girdlestone arthroplasty may be an option to consider, though it may not give requisite relief to patient in some cases. In such situations total hip arthroplasty procedure, though technically challenging will give stable painless hip to the patient. PMID:27299043

  7. Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy

    SciTech Connect

    Mariados, Neil; Sylvester, John; Shah, Dhiren; Karsh, Lawrence; Hudes, Richard; Beyer, David; Kurtzman, Steven; Bogart, Jeffrey; Hsi, R. Alex; Kos, Michael; Ellis, Rodney; Logsdon, Mark; Zimberg, Shawn; Forsythe, Kevin; Zhang, Hong; Soffen, Edward; Francke, Patrick; Mantz, Constantine; Rossi, Peter; DeWeese, Theodore; and others

    2015-08-01

    Purpose: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. Methods and Materials: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control). Patients received postprocedure CT and MRI planning scans and underwent image guided intensity modulated radiation therapy (79.2 Gy in 1.8-Gy fractions). Spacer safety and impact on rectal irradiation, toxicity, and quality of life were assessed throughout 15 months. Results: Spacer application was rated as “easy” or “very easy” 98.7% of the time, with a 99% hydrogel placement success rate. Perirectal spaces were 12.6 ± 3.9 mm and 1.6 ± 2.0 mm in the spacer and control groups, respectively. There were no device-related adverse events, rectal perforations, serious bleeding, or infections within either group. Pre-to postspacer plans had a significant reduction in mean rectal V70 (12.4% to 3.3%, P<.0001). Overall acute rectal adverse event rates were similar between groups, with fewer spacer patients experiencing rectal pain (P=.02). A significant reduction in late (3-15 months) rectal toxicity severity in the spacer group was observed (P=.04), with a 2.0% and 7.0% late rectal toxicity incidence in the spacer and control groups, respectively. There was no late rectal toxicity greater than grade 1 in the spacer group. At 15 months 11.6% and 21.4% of spacer and control patients, respectively, experienced 10-point declines in bowel quality of life. MRI scans at 12 months verified spacer absorption. Conclusions: Spacer

  8. Hip Resurfacing: International Perspectives: Review Article.

    PubMed

    Girard, Julien

    2017-02-01

    The hip resurfacing concept was developed for young and active patients, especially for femoral bone stock preservation. However, concerns about metal-on-metal bearings with adverse reactions to metal debris have led to a drop off in hip-resurfacing procedures. The goal of this review is to evaluate our current knowledge of survivorship of second-generation hip resurfacing devices and elaborate international perspectives for product improvement. A comprehensive literature search provided information on national joint arthroplasty registers worldwide with a minimum of 3000 reported hip resurfacings. It culminated in the analysis of six registers. Long-term data showed that available hip resurfacing device survivorship ranged from 95 to 99.7% with 10 years of follow-up, in selected patient populations. The criteria for success were well known, male gender, good bone quality, head component size greater than 48 mm, and cup inclination less than 45°. On the other hand, the recent recall of some hip-resurfacing devices has resulted in huge medico-legal problems and has discredited all implants. It has brought about the recent evolution of hip resurfacing. Femoral fixation is now available for cemented and cementless surfaces. Bearings are still always metal-on-metal, but new types have come on board. Newer designs suggest that ceramic-on-ceramic, cross-linked polyethylene, and oxinium may be applied in this configuration. In 2015, the evolution of hip resurfacing is ongoing in terms of implant design, alternative bearings, and implant fixation with hopes of improving survivorship.

  9. Are hip hemiarthroplasty and total hip arthroplasty infections different entities? The importance of hip fractures.

    PubMed

    del Toro, M D; Nieto, I; Guerrero, F; Corzo, J; del Arco, A; Palomino, J; Nuño, E; Lomas, J M; Natera, C; Fajardo, J M; Delgado, J; Torres-Tortosa, M; Romero, A; Martín-Rico, P; Muniain, M Á; Rodríguez-Baño, J

    2014-08-01

    Hip hemiarthroplasty (HHA) and total hip arthroplasty (THA) infections are usually considered as one entity; however, they may show important differences. We analyze these differences, as well as predictors of treatment failure (TF) and poor functional status among patients with prosthetic hip infections (PHIs). A multicenter cohort study of consecutive patients with PHIs was performed. The main outcome variable was TF after the first surgical treatment performed to treat the infection. Multivariate analysis was used to identify predictors of TF. A total of 127 patients with PHI were included (43 HHA, 84 THA). Patients with HHA infections were more frequently women (88% vs. 54%; p < 0.001), had comorbidities (86% vs. 67%, p = 0.02), and were older (median age 79 vs. 65 years, p < 0.001), and the reason for arthroplasty was more frequently a fracture (100% vs. 18%, p < 0.001). Failure of initial treatment and crude mortality were more frequent among HHA patients (44% vs. 23%, p = 0.01 and 28% vs. 7%, p = 0.001, respectively). However, HHA was not associated with TF in the multivariate analysis when hip fracture was considered; thus, variables independently associated with TF were hip fracture, inadequate surgical management, prosthesis retention, and higher C-reactive protein level. Failure of the first surgical treatment was associated with poorer functional status. HHA and THA infections showed significant differences in epidemiology, clinical features, and outcome. Although patients with HHA infections had a higher risk of TF, this was related to the reason for hip implant: a hip fracture. Success of the initial management of infection is a predictor of better clinical and functional outcome.

  10. Investigation and analysis of dual-k spacer with different materials and spacer lengths for nanowire-FET performance

    NASA Astrophysics Data System (ADS)

    Ko, Hyungwoo; Kim, Jongsu; Kang, Myounggon; Shin, Hyungcheol

    2017-10-01

    In this work, dual-k spacer structures are investigated using a variety of materials along the high-k spacer length in detail. It is known that not only the higher permittivity materials of high-k spacer boost the on-current but also lower permittivity materials of low-k spacer effectively reduce the off-current. By compared the results of other various single spacers and dual-k spacers, it is HfO2/Vacuum dual-k spacer that shows relatively higher ION, ION/IOFF, better immunity of short channel effects and outstanding device performances.

  11. Outcome of total knee replacement following explantation and cemented spacer therapy

    PubMed Central

    Ghanem, Mohamed; Zajonz, Dirk; Bollmann, Juliane; Geissler, Vanessa; Prietzel, Torsten; Moche, Michael; Roth, Andreas; Heyde, Christoph-E.; Josten, Christoph

    2016-01-01

    Background: Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation. Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient’s group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation. Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data

  12. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  13. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  14. Complex primary total hip arthroplasty.

    PubMed

    Boisgard, S; Descamps, S; Bouillet, B

    2013-02-01

    Although total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that

  15. Comparative evaluation of market spacer and home made spacer in the management of bronchial asthma.

    PubMed

    Rajkumar; Vatsa, H K; Gaur, S N

    2002-03-01

    A study was conducted to compare the efficacy of market available spacer (with valve) and home made spacer (without valve)--Bislery bottle. Fifteen patients of bronchial asthma were included in the study. With the use of both devices there was significant bronchodilator effect. The reversibility using Bislery bottle was same as with spacer (market available) while comparing the FVC, FEV1, FEV1/FVC %, FEF 25-75 and PEFR value. The difference in percent change in reversibility values by both the devices was not statistically significant (p < 0.05). We concluded that the Bislery bottle (without valve) is very cheap compared to market-available spacer and is equally effective which, therefore, can be substituted in bronchial asthma patients, who are unable to afford the cost of market available spacers.

  16. The ribosomal gene spacer region in archaebacteria

    NASA Technical Reports Server (NTRS)

    Achenbach-Richter, L.; Woese, C. R.

    1988-01-01

    Sequences for the spacer regions that separate the 16S and 23S ribosomal RNA genes have been determined for four more (strategically placed) archaebacteria. These confirm the general rule that methanogens and extreme halophiles have spacers that contain a single tRNAala gene, while tRNA genes are not found in the spacer region of the true extreme thermophiles. The present study also shows that the spacer regions from the sulfate reducing Archaeglobus and the extreme thermophile Thermococcus (both of which cluster phylogenetically with the methanogens and extreme halophiles) contain each a tRNAala gene. Thus, not only all methanogens and extreme halophiles show this characteristic, but all organisms on the "methanogen branch" of the archaebacterial tree appear to do so. The finding of a tRNA gene in the spacer region of the extreme thermophile Thermococcus celer is the first known phenotypic property that links this organism with its phylogenetic counterparts, the methanogens, rather than with its phenotypic counterparts, the sulfur-dependent extreme thermophiles.

  17. A finite element study on the mechanical response of the head-neck interface of hip implants under realistic forces and moments of daily activities: Part 1, level walking.

    PubMed

    Farhoudi, Hamidreza; Fallahnezhad, Khosro; Oskouei, Reza H; Taylor, Mark

    2017-08-12

    This paper investigates the mechanical response of a modular head-neck interface of hip joint implants under realistic loads of level walking. The realistic loads of the walking activity consist of three dimensional gait forces and the associated frictional moments. These forces and moments were extracted for a 32mm metal-on-metal bearing couple. A previously reported geometry of a modular CoCr/CoCr head-neck interface with a proximal contact was used for this investigation. An explicit finite element analysis was performed to investigate the interface mechanical responses. To study the level of contribution and also the effect of superposition of the load components, three different scenarios of loading were studied: gait forces only, frictional moments only, and combined gait forces and frictional moments. Stress field, micro-motions, shear stresses and fretting work at the contacting nodes of the interface were analysed. Gait forces only were found to significantly influence the mechanical environment of the head-neck interface by temporarily extending the contacting area (8.43% of initially non-contacting surface nodes temporarily came into contact), and therefore changing the stress field and resultant micro-motions during the gait cycle. The frictional moments only did not cause considerable changes in the mechanical response of the interface (only 0.27% of the non-contacting surface nodes temporarily came into contact). However, when superposed with the gait forces, the mechanical response of the interface, particularly micro-motions and fretting work, changed compared to the forces only case. The normal contact stresses and micro-motions obtained from this realistic load-controlled study were typically in the range of 0-275MPa and 0-38µm, respectively. These ranges were found comparable to previous experimental displacement-controlled pin/cylinder-on-disk fretting corrosion studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Hip flexor strain - aftercare

    MedlinePlus

    ... flexor - aftercare; Hip flexor injury - aftercare; Hip flexor tear - aftercare; Iliopsoas strain - aftercare; Strained iliopsoas muscle - aftercare; Torn iliopsoas muscle - aftercare; Psoas strain - aftercare

  19. An intraoperatively moulded PMMA prostheses like spacer for two-stage revision of infected total knee arthroplasty.

    PubMed

    Kohl, Sandro; Evangelopoulos, Dimitrios S; Kohlhof, Hendrik; Krueger, Andreas; Hartel, Maximilian; Roeder, Christoph; Eggli, Stefan

    2011-12-01

    We report a series of 16 consecutive total knee arthroplasty (TKA) revision procedures for deep infection, treated with a newly developed intraoperatively moulded PMMA cement-prostheses-like spacer (CPLS). The standard treatment consisted of a two-stage protocol with initial explantation of the infected components combined with radical debridement, followed by implantation of a temporary cement spacer and final reimplantation of a new TKA. A sterilizeable Teflon tapered aluminium mould was developed for production of a custom made CPLS during the intervention. Stable implantation of the CPLS was achieved with a second cementation, allowing for correct alignment and ligament balancing. The spacer remained 3.5 months on average until reimplantation of a TKA occurred. At time of reimplantation, patients had an average KSS score of 84.44 points with an average flexion capacity of 102°. There was no recurrent infection during the study period of minimum 2 years. With this new technique, a low friction articulation with good stability, high comfort and a better range of motion compared to handcrafted spacers was achieved. The use of this spacer is a time sparing, cheap and convenient option in 2-stage TKA revision.

  20. Hip Squeaking after Ceramic-on-ceramic Total Hip Arthroplasty

    PubMed Central

    Wu, Guo-Liang; Zhu, Wei; Zhao, Yan; Ma, Qi; Weng, Xi-Sheng

    2016-01-01

    Objective: The present study aimed to review the characteristics and influencing factors of squeaking after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) and to analyze the possible mechanisms of the audible noise. Data Sources: The data analyzed in this review were based on articles from PubMed and Web of Science. Study Selection: The articles selected for review were original articles and reviews found based on the following search terms: “total hip arthroplasty”, “ceramic-on-ceramic”, “hip squeaking”, and “hip noise.” Results: The mechanism of the squeaking remains unknown. The possible explanations included stripe wear, edge loading, a third body, fracture of the ceramic liner, and resonance of the prosthesis components. Squeaking occurrence is influenced by patient, surgical, and implant factors. Conclusions: Most studies indicated that squeaking after CoC THA was the consequence of increasing wear or impingement, caused by prosthesis design, patient characteristics, or surgical factors. However, as conflicts exist among different articles, the major reasons for the squeaking remain to be identified. PMID:27453238

  1. [Hip arthroplasty after corrective osteotomies : Pelvis and proximal femur].

    PubMed

    Rath, B; Eschweiler, J; Betsch, M; Quack, V; Lüring, C; Tingart, M

    2016-08-01

    Pelvic and femoral osteotomies are frequently performed in patients with hip dysplasia. The aim of these surgeries are optimal biomechanical conditions of the hip joint thereby avoiding the occurrence of hip osteoarthritis or the delay of initial hip osteoarthritis progression. Nevertheless even with good biomechanical conditions of the hip joint, progression of hip osteoarthritis can be recognized postoperatively. A total hip arthroplasty is indicated even more after a time period with conservative treatment. In preparation for the operation, a detailed documentation of the initial clinical situation, appropriate imaging, implant selection and preoperative planning are mandatory. In addition, a biomechanical model representing the desired pre- and postoperative situation can be included in the preoperative planning. According to the previous osteotomy, the size and shape of the acetabulum after the osteotomy and the current pivot centre of the hip joint should be considered. Depending on these observations the acetabular cup can be directly inserted into the bone stock of the acetabulum or an acetabular plasty is necessary before implantation of the acetabular cup. With respect to the previous osteotomy of the femur, it needs to be clarified wether hardware removal will be necessary before total hip replacement; moreover, the anatomy of the proximal femur is critical. In addition, if necessary, a re-osteotomy of the femur is required to enable a hip stem implantation. Cementless total hip replacement should be preferred due to the younger patient age. The load of the hip replacement depends on the osseous anchoring and primary stability of the acetabular and femoral component.

  2. Separator-spacer for electrochemical systems

    DOEpatents

    Grimes, Patrick G.; Einstein, Harry; Newby, Kenneth R.; Bellows, Richard J.

    1983-08-02

    An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

  3. Funhaler spacer: improving adherence without compromising delivery

    PubMed Central

    Watt, P; Clements, B; Devadason, S; Chaney, G

    2003-01-01

    A novel asthma spacer device, the "Funhaler", incorporates incentive toys which are isolated from the main inspiratory circuit by a valve. Here we show that its use does not compromise drug delivery. Improved adherence combined with satisfactory delivery characteristics suggest that the Funhaler may be useful for management of young asthmatics. PMID:12818901

  4. Total hip arthroplasty instability in Italy.

    PubMed

    Falez, Francesco; Papalia, Matteo; Favetti, Fabio; Panegrossi, Gabriele; Casella, Filippo; Mazzotta, Gianluca

    2017-03-01

    Hip dislocation is a major and common complication of total hip arthroplasty (THA), which appears with an incidence between 0.3% and 10% in primary total hip arthroplasties and up to 28% in revision THA. The hip dislocations can be classified into three groups: early, intermediate and late. Approximately two-thirds of cases can be treated successfully with a non-operative approach. The rest require further surgical intervention. The prerequisite to developing an appropriate treatment strategy is a thorough evaluation to identify the causes of the dislocation. In addition, many factors that contribute to THA dislocation are related to the surgical technique, mainly including component orientation, femoral head diameter, restoration of femoral offset and leg length, cam impingement and condition of the soft tissues. The diagnosis of a dislocated hip is relatively easy because the clinical situation is very typical. Having identified a dislocated hip, the first step is to perform a closed reduction of the implant. After reduction you must perform a computed tomography scan to evaluate the surgical options for treatment of recurrent dislocation that include: revision arthroplasty, modular components exchange, dual-mobility cups, large femoral heads, constrained cups, elimination of impingement and soft tissue procedures. The objective is to avoid further dislocation, a devastating event which is increasing the number of operations on the hip. To obtain this goal is useful to follow an algorithm of treatment, but the best treatment remains prevention.

  5. Outcome of total hip arthroplasty as a salvage procedure for failed infected internal fixation of hip fractures

    PubMed Central

    Mohanty, Shubhranshu S; Agashe, Mandar V; Sheth, Binoti A; Dash, Kumar K

    2013-01-01

    Background: Failed infected internal fixation produces significant pain and functional disability. In infected internal fixation of hip fractures with partial or complete head destruction, total hip arthroplasty (THA) can be technically challenging; however, it restores hip biomechanics. The present study is to evaluate the results and assess the complications of THA following failed infected internal fixation of these fractures. Materials and Methods: A retrospective review of prospectively collected data in a tertiary healthcare center was performed of 20 consecutive patients of THA following failed infected internal fixation operated between September 2001 and November 2007. There were 11 dynamic hip screw failures for intertrochanteric fractures, 6 failed osteotomies following transcervical fractures, and 3 failed screw fixations for transcervical fractures. Results: The average age of the patients was 48.5 years (range 28-70 years) and the average followup period was 6.5 years (range 3.5-10.5 years). An indigenously designed cement spacer was used in a majority of patients (n = 15). The custom-made antibiotic impregnated cement spacer was prepared on-table, with the help of a K-nail bent at 130°, long stem Austin Moore's prosthesis (n=1), Charnley's prosthesis (n=1), or bent Rush nail (n=1). The antibiotic mixed cement was coated over the hardware in its doughy phase and appropriately shaped using an asepto syringe or an indigenously prepared spacer template. Nineteen of the 20 patients underwent two-stage revision surgeries. The average Harris hip score improved from 35.3 preoperatively to 82.85 postoperatively at the last followup. A significant difference was found (P < 0.0001). None of the patients had recurrence of infection. Conclusions: The results were comparable to primary arthroplasty in femoral neck fractures. Thus, THA is a useful salvage procedure for failed infected internal fixation of hip fractures. PMID:23533069

  6. Hip psychometrics.

    PubMed

    Baldwin, Peter; Bernstein, Joseph; Wainer, Howard

    2009-07-30

    When data are abundant relative to the number of questions asked of them, answers can be formulated using little more than those data. But when data grow more sparse, so too does our tendency to lean on strong models to help us draw inferences. In this research we show how a strong item response model embedded within a fully Bayesian framework allows us to answer two important questions about the reliability and consistency of the clinical diagnosis of hip fractures from very limited data. We also show how the model automatically adjusts diagnoses for biases among the surgeons judging the radiographs. This research illustrates how a Bayesian approach expands the range of problems on which item response models can profitably be used.

  7. Total hip arthroplasty.

    PubMed Central

    Siopack, J S; Jergesen, H E

    1995-01-01

    Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy. In this review we briefly summarize the evolution of total hip arthroplasty, the design and development of prosthetic hip components, and the current clinical indications for this procedure. The possible complications of total hip arthroplasty, its clinical performance over time, and future directions in hip replacement surgery are also discussed. Images PMID:7725707

  8. Engineered porous metals for implants

    NASA Astrophysics Data System (ADS)

    Vamsi Krishna, B.; Xue, Weichang; Bose, Susmita; Bandyopadhyay, Amit

    2008-05-01

    Interest is significant in patient-specific implants with the possibility of guided tissue regeneration, particularly for load-bearing implants. For such implants to succeed, novel design approaches and fabrication technologies that can achieve balanced mechanical and functional performance in the implants are necessary. This article is focused on porous load-bearing implants with tailored micro-as well as macrostructures using laser-engineered net shaping (LENS™), a solid freeform fabrication or rapid prototyping technique that can be used to manufacture patient-specific implants. This review provides an insight into LENS, some properties of porous metals, and the potential applications of this process to fabricate unitized structures which can eliminate longstanding challenges in load-bearing implants to increase their in-vivo lifetime, such as in a total hip prosthesis.

  9. A comparison of total hip resurfacing and total hip arthroplasty - patients and outcomes.

    PubMed

    Fowble, Vincent A; dela Rosa, Mylene A; Schmalzried, Thomas P

    2009-01-01

    A comparison of pertinent preoperative and postoperative data relative to total hip resurfacing versus total hip arthroplasty (THA) would assist in evaluating current perceptions in outcome. We compared 50 consecutive metal-metal resurfacing replacements in 50 patients with 44 consecutive conventional total hip arthroplasties in 35 patients, who were implanted during the same time period, by the same surgeon, and followed prospectively for 2 to 4 years. The patients undergoing hip resurfacing were 62% male, 9 years younger, and 3.2 inches taller, with a lower mean body mass index and American Society of Anesthesiologists (ASA) grade than patients undergoing total hip arthroplasty. Preoperatively, patients undergoing resurfacing had a lower Harris hip score (46 vs 52 points), more pain, higher UCLA (University of California at Los Angeles) activity scores (4.2 vs 3.6), and better range of motion. Surgical time for resurfacing was 18% longer, but there was less total blood loss and fewer transfusions. Postoperatively, there was no difference in Harris hip score (97 vs 96). Patients undergoing resurfacing had higher function, Short Form-12 physical activity scores, and UCLA activity scores, but also a higher incidence of slight or mild pain. There were no differences in postoperative range of motion or dislocation (one each). The preoperative characteristics and general health status of the average patient undergoing resurfacing are more favorable than that of the average patient undergoing conventional total hip arthroplasty. Caution should be applied in attributing differences in outcomes directly to the arthroplasty technology.

  10. Design of an advanced temporary hip prosthesis for an effective recovery of septic mobilizations: a preliminary study.

    PubMed

    Danti, S; Rizzo, C; Polacco, G; Cascone, M G; Giusti, P; Lisanti, M

    2007-10-01

    The purpose of this study was the design and preliminary feasibility study of an advanced temporary hip prosthesis acting as an in-site drug dispensing system. An interactive device was designed to improve the recovery of bone infections compared to the mechanical spacers currently used in septic mobilizations. A commercial device was chosen and modified specifically for the purpose. First of all, the device was provided with a hydraulic multi-channel system connected via catheter to a subcutaneous valve, refillable with a drug aqueous solution from the outside. Moreover, since it allows samples of biological fluids for analyses to be drawn directly from the implantation site, this chemical dispensing system was designed to allow the course of infections to be monitored and customized therapies to be dosed. The insertion of biocompatible membranes inside the channel ends was considered essential to prevent their occlusion by fibrous tissue growth, thereby preserving the device functionality. Moreover, a biodegradable spongy ring was designed to be fixed onto the stem in distal position both to give primary stability to the implant and to act simultaneously as a scaffold for bonelike cell growth.

  11. [Resurfacing arthroplasty of the hip].

    PubMed

    Knecht, A; Witzleb, W-C; Günther, K-P

    2005-01-01

    Currently, an increase in resurfacing arthroplasty in the treatment of hip osteoarthritis--especially in young adults--can be observed. New bearing technologies (mainly metal-on-metal surfaces) show better tribologic results than historical designs (e.g. the Wagner cup). At present, it is unclear whether these modifications and a definitively low dislocation rate--due to the large head diameter--can be supported by further good clinical results. The quantity as well as the quality of the available investigations prevents a definite opinion at the moment. Appropriate clinical studies with documented radiographic follow-up are necessary to compare the outcome of these new implants with standard techniques.

  12. Tube support grid and spacer therefor

    DOEpatents

    Ringsmuth, Richard J.; Kaufman, Jay S.

    1986-01-01

    A tube support grid and spacers therefor provide radially inward preloading of heat exchange tubes to minimize stress upon base welds due to differential thermal expansion. The grid comprises a concentric series of rings and spacers with opposing concave sides for conforming to the tubes and V-shaped ends to provide resilient flexibility. The flexibility aids in assembly and in transmitting seismic vibrations from the tubes to a shroud. The tube support grid may be assembled in place to achieve the desired inwardly radial preloading of the heat exchange tubes. Tab and slot assembly further minimizes stresses in the system. The radii of the grid rings may be preselected to effect the desired radially inward preloading.

  13. Heterogeneous diversity of spacers within CRISPR

    NASA Astrophysics Data System (ADS)

    Deem, Michael; He, Jiankui

    2011-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102

  14. [Juvenile rheumatoid diseases: Endoprosthetic care of destroyed hip joints].

    PubMed

    Rehart, S; Henniger, M

    2015-07-01

    Patients with juvenile idiopathic arthritis (JIA) often suffer from involvement of the hip joints, with joint destruction and related functional limitations, making hip replacement necessary. To discover what special features are to be expected in patients with JIA and hip arthroplasty and what impact they have on surgical indication, choice of implant, and technique. Selective literature review and evaluation of our patient population. Compared with osteoarthritis patients, JIA patients are on average much younger at the time of hip replacement. Owing to the onset of the disease in childhood or adolescence and the frequent glucocorticoid therapy, growth disorders or abnormal anatomical findings are common in these patients. Bone density is often reduced at an early age. The perioperative management of medication has to be planned. Special implants for patients with rheumatic diseases do not exist, but the above peculiarities of this group of patients should be considered for surgical procedure and choice of implant and material. Overall, the results of hip arthroplasty in juvenile rheumatic diseases, in terms of pain relief and functional improvement, are good. The limited life of the arthroplasty is problematic. By relieving pain, improvement of the range of motion and activity level very high patient satisfaction is usually achieved by hip arthroplasty in JIA patients. In the case of involvement of the contralateral hip or the ipsilateral knee joint it may be useful to perform a simultaneous, single-stage joint replacement of both joints.

  15. Improved nuclear fuel assembly grid spacer

    DOEpatents

    Marshall, John; Kaplan, Samuel

    1977-01-01

    An improved fuel assembly grid spacer and method of retaining the basic fuel rod support elements in position within the fuel assembly containment channel. The improvement involves attachment of the grids to the hexagonal channel and of forming the basic fuel rod support element into a grid structure, which provides a design which is insensitive to potential channel distortion (ballooning) at high fluence levels. In addition the improved method eliminates problems associated with component fabrication and assembly.

  16. Total hip arthroplasty in the ankylosed hip.

    PubMed

    Swanson, Megan A; Huo, Michael H

    2011-12-01

    Altered biomechanics secondary to hip ankylosis often result in degeneration of the lumbar spine, ipsilateral knee, and contralateral hip and knee. Symptoms in these joints may be reduced with conversion total hip arthroplasty (THA) of the ankylosed hip. THA in the ankylosed hip is a technically challenging procedure, and the overall clinical outcome is generally less satisfactory than routine THA performed for osteoarthritis and other etiologies. Functional integrity of the hip abductor muscles is the most important predictor of walking ability following conversion THA. Many patients experience persistent limp, and it can take up to 2 years to fully assess final functional outcome. Risk factors cited for increased risk of failed THA include prior surgical ankylosis and age <50 years at the time of conversion THA.

  17. Durable infection control and function with the PROSTALAC spacer in two-stage revision for infected knee arthroplasty.

    PubMed

    Gooding, Christopher R; Masri, Bassam A; Duncan, Clive P; Greidanus, Nelson V; Garbuz, Donald S

    2011-04-01

    A two-stage revision total knee arthroplasty is recognized as the gold standard in the treatment of infection. However, traditional spacers limit function in the interval between the two stages and may cause instability, scarring, and bone erosion. The PROSTALAC knee spacer is an antibiotic-loaded cement articulating spacer that allows some movement of the knee between stages. Whether motion enhances long-term function is unknown. We therefore identify the rate of control of infection using the PROSTALAC exchange spacer and to assess the clinical outcome after implantation with a definitive implant. We retrospectively reviewed 115 knees that underwent two-stage exchange with the PROSTALAC spacer. Forty-eight of these had a minimum followup of 5 years (mean, 9 years; range, 5-12 years). At last review, 101 of the 115 knees (88%) had no evidence of infection. Of the 14 knees that became reinfected, four were from the same organism and 10 were with a different organism. After further intervention, using the two-stage approach again, the infection was controlled in 12 of the 14 initially reinfected cases, resulting in a failure to cure in only two cases. We observed improvements in mean WOMAC, Oxford, UCLA, and Patient Satisfaction scores at last review. The PROSTALAC functional spacer was associated with a 98% rate of control of infection and improvements in the quality-of-life outcomes in the treatment of chronically infected total knee arthroplasties. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

  18. Self-aligned quadruple patterning using spacer on spacer integration optimization for N5

    NASA Astrophysics Data System (ADS)

    Thibaut, Sophie; Raley, Angélique; Mohanty, Nihar; Kal, Subhadeep; Liu, Eric; Ko, Akiteru; O'Meara, David; Tapily, Kandabara; Biolsi, Peter

    2017-04-01

    To meet scaling requirements, the semiconductor industry has extended 193nm immersion lithography beyond its minimum pitch limitation using multiple patterning schemes such as self-aligned double patterning, self-aligned quadruple patterning and litho-etch / litho etch iterations. Those techniques have been declined in numerous options in the last few years. Spacer on spacer pitch splitting integration has been proven to show multiple advantages compared to conventional pitch splitting approach. Reducing the number of pattern transfer steps associated with sacrificial layers resulted in significant decrease of cost and an overall simplification of the double pitch split technique. While demonstrating attractive aspects, SAQP spacer on spacer flow brings challenges of its own. Namely, material set selections and etch chemistry development for adequate selectivities, mandrel shape and spacer shape engineering to improve edge placement error (EPE). In this paper we follow up and extend upon our previous learning and proceed into more details on the robustness of the integration in regards to final pattern transfer and full wafer critical dimension uniformity. Furthermore, since the number of intermediate steps is reduced, one will expect improved uniformity and pitch walking control. This assertion will be verified through a thorough pitch walking analysis.

  19. Hip resurfacing after iliofemoral distraction for type IV developmental dysplasia of the hip a case report.

    PubMed

    Sambri, A; Cadossi, M; Mazzotti, A; Faldini, C; Giannini, S

    2015-01-01

    Osteoarthritis secondary to developmental dysplasia of the hip is a surgical challenge because of the modified anatomy of the acetabulum which is deficient in its shape with poor bone quality, torsional deformities of the femur and the altered morphology of femoral head. Particularly in Crowe type III and IV, additional surgical challenges are present, such as limb-length discrepancy and adductor muscle contractures. This is a bilateral hip dysplasia case where bilateral hip replacement was indicated, on the left side with a resurfacing one and on the other side a two stage procedure using a iliofemoral external fixator to restore equal leg length with a lower risk of complications. This case report shows both the negative clinical outcome of the left and the excellent one of the right hip where the dysplasia was much more severe. Patient selection and implant positioning are crucial in determining long-term results.

  20. Choice and doses of antibacterial agents for cement spacers in treatment of prosthetic joint infections: review of published studies.

    PubMed

    Iarikov, D; Demian, H; Rubin, D; Alexander, J; Nambiar, S

    2012-12-01

    Addition of antibacterial drugs to interim antibacterial cement spacers (ACSs) is considered to be standard of care for surgical revision in prosthetic joint infections (PJIs). We reviewed published studies evaluating the choice and doses of antibacterials in spacers. We conducted a PubMed search of all clinical study reports evaluating the use of ACSS in a 2-stage hip or knee arthroplasty for treatment of PJI (1988 through August 2011). The trial design, antibacterials used, and end points studied were analyzed. No randomized trials were found comparing either ACSs with different concentrations of antibacterials or ACSs with or without antibacterials. Most of the studies were uncontrolled and used various time points to evaluate the outcome. Twenty publications that reported doses of antibacterials in spacers and had a follow-up of ≥ 24 months after the second stage were selected for review. Most ACSs included vancomycin and aminoglycosides. The doses of aminoglycosides and vancomycin ranged from 0.25 to 4.8 g and from 1 to 4 g, respectively, per 4 g of cement. No association between reported eradication of the infection and antibacterial load was found. Published data do not allow evaluation of whether antibacterials in temporary cement spacers provide additional benefits in the treatment of PJI, compared with systemic antibacterials, and are not sufficient to support recommendations on dosages. Complications of ACSs have not been consistently analyzed. Prospective randomized trials comparing spacers with and without antibacterials or spacers with different loads of antibacterials are needed to evaluate the safety and efficacy of ACSs.

  1. Novel Highly Porous Metal Technology in Artificial Hip and Knee Replacement: Processing Methodologies and Clinical Applications

    NASA Astrophysics Data System (ADS)

    Muth, John; Poggie, Matthew; Kulesha, Gene; Michael Meneghini, R.

    2013-02-01

    Hip and knee replacement can dramatically improve a patient's quality of life through pain relief and restored function. Fixation of hip and knee replacement implants to bone is critical to the success of the procedure. A variety of roughened surfaces and three-dimensional porous surfaces have been used to enhance biological fixation on orthopedic implants. Recently, highly porous metals have emerged as versatile biomaterials that may enhance fixation to bone and are suitable to a number of applications in hip and knee replacement surgery. This article provides an overview of several processes used to create these implant surfaces.

  2. [Resurfacing arthroplasty of the hip].

    PubMed

    Rudert, M; Gerdesmeyer, L; Rechl, H; Juhnke, P; Gradinger, R

    2007-04-01

    Resurfacing arthroplasty is regarded as an attractive method, especially for the young patient who needs a hip replacement. However, the high expectations regarding this new technique in THR must first be met. Earlier experiences with similar forms of surface replacement have led to high revision rates with early aseptic wear induced component loosening and neck fractures. Technical progresses in production techniques for metal-on-metal articulations with minimized wear have enabled the introduction of new surface replacements for the hip joint. Long-term results of these resurfacing arthroplasties are still due. Femoral neck fractures and femoro-acetabular impingement are possible early complications which require revision. The implantation of these systems requires a high degree of operative skill and experience on the part of the surgeon. Approach dependent trauma to the musculature and endangering of the blood supply to the femoral head is balanced with the positive effect of the preservation of femoral bone stock and better options in case of revision. Whether the younger patient with a higher activity profile and an increased chance of implant loosening actually profits from the resurfacing arthroplasty will be determined in the future.

  3. Minimum ten-year results of primary bipolar hip arthroplasty for degenerative arthritis of the hip.

    PubMed

    Pellegrini, Vincent D; Heiges, Bradley A; Bixler, Brian; Lehman, Erik B; Davis, Charles M

    2006-08-01

    Bipolar hip arthroplasty has been advocated by some as an alternative to total hip arthroplasty for the treatment of degenerative arthritis of the hip. We sought to assess the results of this procedure at our institution after a minimum duration of follow-up of ten years. We retrospectively reviewed a consecutive series of 152 patients (173 hips) who underwent primary bipolar hemiarthroplasty for the treatment of symptomatic degenerative arthritis of the hip with a cementless femoral component between 1983 and 1987. Of the original cohort of 152 patients, ninety-two patients (104 hips) were available for clinical and radiographic review at a mean of 12.2 years postoperatively. At the time of the latest follow-up, self-administered Harris hip questionnaires were used to assess pain, mobility, activity level, and overall satisfaction with the procedure. Biplanar hip radiographs were made to evaluate bipolar shell migration, osteolysis, and femoral stem fixation. At the time of the latest follow-up, nineteen patients (nineteen hips) had undergone revision to total hip arthroplasty because of mechanical failure, and three patients (three hips) were awaiting revision because of symptomatic radiographic mechanical failure. Twelve acetabular revisions were performed or scheduled for the treatment of pelvic osteolysis or protrusio acetabuli secondary to component migration. Acetabular reconstruction required bone-grafting, an oversized shell, and/or a pelvic reconstruction ring. The overall rate of mechanical failure was 21.2% (twenty-two of 104 hips), with 91% (twenty) of the twenty-two failures involving the acetabular component. Reaming of the acetabulum at the time of the index arthroplasty was associated with a 6.4-fold greater risk of revision. The rate of implant survival, with revision because of mechanical failure as the end point, was 94.2% for femoral components and 80.8% for acetabular components at a mean of 12.2 years. Of the remaining sixty-nine patients

  4. Hip fracture surgeries

    MedlinePlus

    ... References Goulet JA. Hip dislocations. In: Browner BD, Jupiter JB, Krettek C, Anderson PA, eds. Skeletal Trauma: ... Baumgaertner MR. Intertrochanteric hip fractures. In: Browner BD, Jupiter JB, Krettek C, Anderson PA, eds. Skeletal Trauma: ...

  5. Hip Injuries and Disorders

    MedlinePlus

    ... or falling can all sometimes lead to hip injuries. These include Strains Bursitis Dislocations Fractures Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited ...

  6. Hip replacement - discharge

    MedlinePlus

    ... surgery to replace all or part of your hip joint with an artificial joint called a prosthesis. This ... You're in the Hospital You had a hip joint replacement surgery to replace all or part of ...

  7. Hip joint injection

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/007633.htm Hip joint injection To use the sharing features on this ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ...

  8. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the

  9. Is There Still a Role for Interspinous Spacers in the Management of Neurogenic Claudication?

    PubMed

    Ravindra, Vijay M; Ghogawala, Zoher

    2017-07-01

    Lumbar spinal stenosis with neurogenic claudication is prevalent in the elderly population. Decompression for this condition is the operation most commonly used to treat older patients. Because of the risks associated with open decompression procedures, particularly in older patients with comorbidities, minimally invasive procedures with implantation of interspinous process devices have been developed. This article reviews the current role of interspinous spacers in the treatment of lumbar spinal stenosis with neurogenic claudication and discusses the body of literature surrounding this treatment alternative. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. The Hip Restoration Algorithm

    PubMed Central

    Stubbs, Allston Julius; Atilla, Halis Atil

    2016-01-01

    Summary Background Despite the rapid advancement of imaging and arthroscopic techniques about the hip joint, missed diagnoses are still common. As a deep joint and compared to the shoulder and knee joints, localization of hip symptoms is difficult. Hip pathology is not easily isolated and is often related to intra and extra-articular abnormalities. In light of these diagnostic challenges, we recommend an algorithmic approach to effectively diagnoses and treat hip pain. Methods In this review, hip pain is evaluated from diagnosis to treatment in a clear decision model. First we discuss emergency hip situations followed by the differentiation of intra and extra-articular causes of the hip pain. We differentiate the intra-articular hip as arthritic and non-arthritic and extra-articular pain as surrounding or remote tissue generated. Further, extra-articular hip pain is evaluated according to pain location. Finally we summarize the surgical treatment approach with an algorithmic diagram. Conclusion Diagnosis of hip pathology is difficult because the etiologies of pain may be various. An algorithmic approach to hip restoration from diagnosis to rehabilitation is crucial to successfully identify and manage hip pathologies. Level of evidence: V. PMID:28066734

  11. Hip Labral Tear

    MedlinePlus

    ... the outside rim of the socket of your hip joint. In addition to cushioning the hip joint, the labrum acts like a rubber seal or gasket to help hold the ball at the top of your thighbone securely within your hip socket. Athletes who participate in such sports as ...

  12. Preoperative planning for revision total hip arthroplasty.

    PubMed

    Barrack, Robert L; Burnett, R Stephen J

    2006-01-01

    Revision total hip arthroplasty is associated with more perioperative complications and unexpected findings than are encountered during primary total hip arthroplasty. Special instruments, implants, bone grafts, and other accessories may be required to treat complex problems that arise during revision surgery. Preoperative planning is important to anticipate potential complications and to ensure that all possible needed materials are readily available during surgery. Patients and their families also should be counseled on the specific additional risk factors involved in this complex surgery. An organized approach to revision total hip arthroplasty helps to reduce surgical time, minimize risks, decrease the stress level of the entire surgical team, and to increase the rate of successful outcomes for patients.

  13. Cochlear Implants

    MedlinePlus

    ... Medical Procedures Implants and Prosthetics Cochlear Implants Cochlear Implants Share Tweet Linkedin Pin it More sharing options ... normal ear, ear with hearing loss, and cochlear implant procedure Welcome to the Food and Drug Administration ( ...

  14. Robot-assisted total hip arthroplasty.

    PubMed

    Banerjee, Samik; Cherian, Jeffery J; Elmallah, Randa K; Pierce, Todd P; Jauregui, Julio J; Mont, Michael A

    2016-01-01

    Precise and accurate biomechanical reconstruction during total hip arthroplasty (THA) is essential for durable long-term survivorship. Accurate fit of cementless hip implants is also crucial to reduce micromotion between the bone-implant interfaces to allow for stable osseointegration. Robotic technology aims to minimize potential human errors and improve implant alignment and fit, and address persisting concerns with modern-day cementless THA. Although robotic THA dates back to the early 1990s, concerns with increased operating times, costs, and complications led to its withdrawal. However, semi-active systems have renewed interest in robot-assisted joint arthroplasty. We reviewed the current technology, its potential benefits, and the reported clinical and radiographic outcomes. Early evidence suggests that robotic use may lead to more accurate reconstruction of radiographic parameters, such as implant positioning, fit, center-of-rotation, and leg-length discrepancy. Further research is needed to determine if these will translate into better outcomes and improved implant longevity to justify increased costs.

  15. NEUTRONIC REACTOR SHIELD AND SPACER CONSTRUCTION

    DOEpatents

    Wigner, E.P.; Ohlinger, L.A.

    1958-11-18

    Reactors of the heterogeneous, graphite moderated, fluid cooled type and shielding and spacing plugs for the coolant channels thereof are reported. In this design, the coolant passages extend horizontally through the moderator structure, accommodating the fuel elements in abutting end-to-end relationship, and have access openings through the outer shield at one face of the reactor to facilitate loading of the fuel elements. In the outer ends of the channels which extend through the shields are provided spacers and shielding plugs designed to offer minimal reslstance to coolant fluid flow while preventing emanation of harmful radiation through the access openings when closed between loadings.

  16. Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up.

    PubMed

    Faldini, Cesare; Miscione, Maria Teresa; Chehrassan, Mohammadreza; Acri, Francesco; Pungetti, Camilla; d'Amato, Michele; Luciani, Deianira; Giannini, Sandro

    2011-12-01

    Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up. Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10-14 years). Average Harris Hip Score was 56 ± 9 (range 45-69) preoperatively, 90 ± 9 (range 81-100) 12 months after surgery, and 91 ± 8 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised. Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results.

  17. Total Hip Joint Replacement Biotelemetry System

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Luntz, R. A.

    1981-01-01

    The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

  18. [History of hip arthroplasty].

    PubMed

    Płomiński, Janusz; Kwiatkowski, Krzysztof

    2007-02-01

    The authors present the history of hip prosthesis in treatment of coxarthrosis. Despite eighty years of experience the problem of gaining good and long-term results still exist and is difficult to solve. Even changing the way on cementless stabilization of prosthesis doesn't has result in solving the problem of aseptic loosening of hip arthroplasty. Problems of wear derbies made the producers find new to reduce particulate debris. The future of hip arthroplasty is connected with hip resurfacing. Moreover, the higher number of primary hip plasty the more prosthesis are loosening. The treatment is far more difficult and more expensive.

  19. The trochanter slide osteotomy approach for resurfacing hip arthroplasty.

    PubMed

    Pitto, Rocco P

    2009-04-01

    The aim of this prospective study was to assess the safety and efficacy of the greater trochanter slide osteotomy approach for resurfacing hip arthroplasty. Fifty consecutive hips (47 patients) with degenerative joint disease were enrolled in the study. Serial clinical and radiological assessments were performed after the index operation. At 1-year follow-up, the clinical outcome and patient satisfaction were rated excellent or good in all hips. The radiological assessment showed signs of satisfactory implant alignment. Periprosthetic fractures and non-unions of the greater trochanter were not observed. The greater trochanter slide osteotomy approach for resurfacing hip arthroplasty is a safe procedure and provides optimal exposure of the acetabulum and proximal femur, maintaining the soft-tissue integrity of the hip joint. Blood supply of the proximal femur is not violated using this approach.

  20. [Cementless total hip arthroplasty: a review].

    PubMed

    Diehl, Peter; Haenle, Maximilian; Bergschmidt, Philipp; Gollwitzer, Hans; Schauwecker, Johannes; Bader, Rainer; Mittelmeier, Wolfram

    2010-10-01

    The purpose of total hip replacement (THR) is the restoration of a painless functioning hip joint with the main focus on the biomechanical properties. Advances in surgical techniques and biomaterial properties currently allow predictable surgical results in most patients. Despite the overwhelming success of this surgical procedure, the debate continues surrounding the optimal choice of implants and fixation. Femoral and acetabular implants with varying geometries and fixation methods are currently available. Problems inherent with acrylic bone cement, however, have encouraged surgeons to use alternative surfaces to allow biologic fixation. Optimal primary and secondary fixation of cementless hip stems is a precondition for long-term stability. Important criteria to achieve primary stability are good rotational and axial stability by press-fit fixation. The objective of the cementless secondary fixation is the biological integration of the implant by bony ingrowth. Nevertheless, current investigations show excellent results of cementless fixation even in older patients with reduced osseous quality. The main advantages of cementless fixation include biological integration, reduced duration of surgery, no tissue damage by cement polymerization and reduction of intraoperative embolisms. In comparison to cemented THR both, cementless sockets and stems provide good long-term results.

  1. Pelvic position and movement during hip replacement.

    PubMed

    Grammatopoulos, G; Pandit, H G; da Assunção, R; Taylor, A; McLardy-Smith, P; De Smet, K A; Murray, D W; Gill, H S

    2014-07-01

    The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior > lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required.

  2. [Old and new materials in the hip prosthesis].

    PubMed

    Kowalczewski, Jacek B; Milecki, Marcin; Marczak, Dariusz

    2006-01-01

    Since the second half of the XX century a steady evolution of hip prosthesis design is taking place. Implant shape, fixation systems and materials are constantly evolving. The paper presents the materials combinations most commonly used in hip prosthesis (metal-metal, metal-polyethylene and ceramic). All the above mentioned materials have been in used for over 25 years, and thanks to minor modification and better quality are widely used all over the world. The authors basing on biochemical studies, clinical observations and personal experience present problems related to materials used in hip prosthesis.

  3. Properties of cellulase immobilized on agarose gel with spacer

    SciTech Connect

    Chim-anage, P.; Kashiwagi, Y.; Magae, Y.; Ohta, T.; Sasaki, T.

    1986-12-01

    Cellulase produced by fungus Trichoderma viride was immobilized on agarose beads (Sepharose 4B) activated by cyanogen bromide and also on activated agarose beads that contained spacer arm (activated Ch-Sepharose 4B and Affi-Gel 15). The CMCase activity retained by immobilized cellulase on activated Sepharose containing the spacer tended to be higher than that immobilized without spacer, although the extent of protein immobilization was lower. Also, the higher substrate specificity for cellulase immobilized on beads with spacer was obtained for cellobiose, acid-swollen cellulose, or cellulose powder. The hydrolysis product from their substrates was mainly glucose. 10 references.

  4. The development process for a new spacer device.

    PubMed

    Watson, Paul

    The British Thoracic Society and Scottish Intercollegiate Guidelines Network recommend that children up to the age of five should use a pressurised metered dose inhaler with a spacer device to deliver inhaled steroids. However, large-volume spacers can be cumbersome, which is why I designed a smaller, more portable device to encourage spacer use. After prototypes were made, the idea was presented to the local NHS innovations department. With its advice and assistance, a collapsible spacer device has been developed. This article describes the product development process.

  5. Chronic Periprosthetic Hip Joint Infection. A Retrospective, Observational Study on the Treatment Strategy and Prognosis in 130 Non-Selected Patients

    PubMed Central

    Troelsen, Anders; Søballe, Kjeld

    2016-01-01

    Introduction Limited information is available regarding the treatment strategy and prognosis of non-selected patients treated for chronic periprosthetic hip joint infection. Such information is important as no head-to-head studies on treatment strategies are available. The purpose of this study is to report on the treatment strategy and prognosis of a non-selected, consecutive patient population Methods We identified 130 patients in the National Patient Registry, consecutively treated for a chronic periprosthetic hip joint infection between 2003–2008 at 11 departments of orthopaedic surgery. We extracted information regarding patient demographics, treatment and outcome. 82 patients were re-implanted in a two-stage revision (national standard), the remaining 48 were not re-implanted in a two-stage revision. We were able to collect up-to-date information on all patients to date of death or medical chart review with a minimum of 5 years follow-up by the nationwide electronic patient record system Results After primary revision surgery, 53 patients (41%) had a spacer in situ, 64 (50%) had a resection arthroplasty and 13 (9%) did not have the infected implant removed. 63% were re-implanted in a two-stage revision. Re-implantation was performed after an interim period of 14 weeks (IQR 10–18). Patients re-implanted were younger (p-value 0.0006), had a lower CCS score (p-value 0.005), a lower ASA score (p-value 0.0001) and a 68% lower mortality risk in the follow-up period (p-value <0.00001). After adjusting for selected confounders, the mortality risk was no longer significantly different. The 5-year re-infection rate after re-implantation was 14.6% (95%CI 8.0–23.1). Re-infections occurred mainly within 3 years of follow-up. The overall 1-year survival rate was 92% (95%CI 86–96) and the overall 5-year survival rate was 68% (95%CI 59–75). The 5-year survival rate after a two-stage revision was 82% (95%CI 71–89) and in those not re-implanted 45% (95%CI 30–58

  6. Uncemented total hip arthroplasty in osteoarthritis of hip secondary to low and high dislocated hips: A mid-term follow-up study

    PubMed Central

    Munigangaiah, Sudarshan; O’Dwyer, Sinead; Masterson, Eric

    2016-01-01

    Background: Performing successful total hip replacement (THR) in dysplastic, subluxed, and dislocated hip is a challenging task. Here, we assessed midterm clinical and radiological outcomes of uncemented total hip arthroplasty in osteoarthritis (OA) of hip secondary to Hartofilakidis low and high-dislocated hips with a mean follow-up of 8.8 years. Materials and Methods: A retrospective study of prospectively collected data was designed involving all consecutive patients who underwent uncemented THR for OA of hip secondary to developmental dysplasia of the hip and Grade II or Grade III Hartofilakidis classification. Results: Thirty-two patients underwent 45 THR, with 23 Grade II (low dislocation) and 22 Grade III (high-dislocation) of Hartofilakidis classification. Thirteen patients had bilateral hip replacements, 19 patients had unilateral THR. There was highly statistically significant difference between preoperative and postoperative HHS and SF-36v2™ at each follow-up. Survivorship of original implant was 98.88% at a mean follow-up of 8.8 years. The mean improvement in leg length in this series was 3.6 cm (1.8-4.5, 95% confidence interval). No sciatic nerve or femoral nerve palsies were observed. Conclusions: Uncemented THR provides better function and quality of life. However, longer follow-up studies are needed to assess survivorship of uncemented THR in Hartofilakidis low and high-dislocations. PMID:27433063

  7. Occult spinous process fractures associated with interspinous process spacers.

    PubMed

    Kim, David H; Tantorski, Mark; Shaw, Jeremy; Martha, Juli; Li, Ling; Shanti, Nael; Rencu, Tal; Parazin, Stephen; Kwon, Brian

    2011-07-15

    Prospective observational study. To provide a more accurate estimate of the rate of acute spinous process fractures associated with IPS surgery. Biomechanical cadaveric studies have suggested adequate spinous process strength to support placement of interspinous process spacers (IPS). Postoperative spinous process fractures have been reported in one%-to 5.8% of patients in previous series based on routine biplanar radiographic evaluation. However, most fractures occur between the base and midportion of the spinous process in an area that is typically difficult to visualize on plain radiographs due to device design. All patients underwent preoperative biplanar plain radiographs and computed tomography (CT) of the lumbar spine to confirm anatomy favorable for IPS placement and rule out fracture or spondylolysis. Postoperatively, all patients underwent repeat CT imaging within six months of surgery, biplanar radiographs at two weeks, six weeks, three months, six months, and one year. All studies were reviewed independently by a neuroradiologist and two orthopedic spine surgeons. Fifty implants (38 L4-5, 12 L3-4) were placed in 38 patients who completed follow-up and were included in final analysis. Three IPS designs were included (34 Medtronic X-STOP titanium, 8 X-STOP PEEK, 8 Lanx Aspen). Postoperative CT revealed 11 nondisplaced spinous process fractures in 11 patients (28.9% of patients, 22% of levels). Five fractures were associated with mild to moderate lumbar back pain and six fractures were asymptomatic. No patient reported a traumatic incident. No fracture was identifiable on plain radiographs. One fracture displaced during follow-up evaluation. Three patients underwent IPS removal and laminectomy. Three fractures healed by CT in one year. Overall, patients with fractures tended toward poorer outcomes by Zurich Claudication Questionnaire (ZCQ) (28.5% vs. 34.8% improvement in symptom severity, P = 0.496; 21.4% vs. 30.7% improvement in physical function, P = 0

  8. The effect of abductor muscle and anterior-posterior hip contact load simulation on the in-vitro primary stability of a cementless hip stem

    PubMed Central

    2010-01-01

    Background In-vitro mechanical tests are commonly performed to assess pre-clinically the effect of implant design on the stability of hip endoprostheses. There is no standard protocol for these tests, and the forces applied vary between studies. This study examines the effect of the abductor force with and without application of the anterior-posterior hip contact force in the in-vitro assessment of cementless hip implant stability. Methods Cementless stems (VerSys Fiber Metal) were implanted in twelve composite femurs which were divided into two groups: group 1 (N = 6) was loaded with the hip contact force only, whereas group 2 (N = 6) was additionally subjected to an abductor force. Both groups were subjected to the same cranial-caudal hip contact force component, 2.3 times body weight (BW) and each specimen was subjected to three levels of anterior-posterior hip contact load: 0, -0.1 to 0.3 BW (walking), and -0.1 to 0.6 BW (stair climbing). The implant migration and micromotion relative to the femur was measured using a custom-built system comprised of 6 LVDT sensors. Results Substantially higher implant motion was observed when the anterior-posterior force was 0.6BW compared to the lower anterior-posterior load levels, particularly distally and in retroversion. The abductor load had little effect on implant motion when simulating walking, but resulted in significantly less motion than the hip contact force alone when simulating stair climbing. Conclusions The anterior-posterior component of the hip contact load has a significant effect on the axial motion of the stem relative to the bone. Inclusion of the abductor force had a stabilizing effect on the implant motion when simulating stair climbing. PMID:20576151

  9. [Hip and knee replacement and sport].

    PubMed

    Flecher, X; Argenson, J N; Aubaniac, J M

    2004-08-01

    Knee or hip arthroplasty in the sportsman raise many problems including the possibility or to come back to sports activities, and the implants longevity. Unicompartimental prosthesis of the knee is a relatively preserving surgery whose results in the long run in particular for the sporting subject can be for some authors sometimes disappointing. Total knee arthroplasty remains more invasive but with functional results always compatible with some sports activities. The functional result depends much on the postoperative, plurifactorial flexion. Concerning the hip, the sportsman, more active and younger than the average population suffering from osteoarthritis suffer statically more of osteoarthritis. The contribution of the total hip prostheses without cement, anatomical even custom, and of the new couples of friction seems to allow a better longevity. In addition, the contribution of the mini-invasive techniques and the computer-assisted surgery seem techniques with a promising future. We present our experience with the unicompartimental arthroplasty, the postoperative flexion in the total knee prostheses and in the hip arthroplasty for the younger patient and the relations between these interventions and sports. Many authors studied the possibilities of sporting recovery (standard of sport and level of practice). The majority of the activities can be taken again, by excluding the sports of team, of ball and the jogging. The contribution of the mini-invasive techniques seems to allow a faster recovery and the uncemented hip prostheses give good long-term results in the young and active patient.

  10. Trajectories of depressive symptoms after hip fracture

    PubMed Central

    Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.

    2016-01-01

    Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed ‘resilient’, ‘distressed’, and ‘depressed’. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698

  11. Trajectories of depressive symptoms after hip fracture.

    PubMed

    Cristancho, P; Lenze, E J; Avidan, M S; Rawson, K S

    2016-05-01

    Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. We enrolled 482 inpatients, aged ⩾60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery-Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Three trajectories emerged according to the course of depressive symptoms, which we termed 'resilient', 'distressed', and 'depressed'. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture.

  12. Comparative study of two materials for dynamic hip screw during fall and gait loading: titanium alloy and stainless steel.

    PubMed

    Taheri, Nooshin S; Blicblau, Aaron S; Singh, Manmohan

    2011-11-01

    Internal fixation with dynamic hip screw is a choice of treatment for hip fractures to stabilize a femoral fracture. Choosing the proper implant and its material has a great effect on the healing process and failure prevention. The purpose of this analysis was to assess biomechanical behavior of dynamic hip screw with two different materials implanted in the femur during fall and gait. A 3D finite element model of an intact femur and a 3D implant within the same femur were developed. A finite element analysis was carried out to establish the effect of load conditions and implant material properties on biomechanical behavior of the dynamic hip screw after internal fixation. Two load configurations are chosen: one simulating the stance phase of the normal gait cycle, and the other replicating a low-energy fall. The implanted femur was investigated with two different materials for the dynamic hip screw: stainless steel and titanium alloy. During stance, more stress is placed on the implanted femur compared with the intact femur. During a fall, the implanted femur is in a greater state of stress, which mostly occurs inside the dynamic hip screw. Titanium alloy decreases stress levels by an average of 40% compared with stainless steel. However, deformation is slightly reduced with a stainless steel dynamic hip screw during both load cases. After internal fixation, dynamic hip screw generates greater stresses within the implanted femur compared with the intact femur under the same loading conditions. A titanium alloy implant appears to undergo less stress from a low-energy fall compared with stainless steel and can be considered the preferred implant material. The critical parts of the dynamic hip screw are the forth distal screw and the plate.

  13. The World Hip Trauma Evaluation Study 3

    PubMed Central

    Parsons, N.; Achten, J.; Griffin, X. L.; Costa, M. L.; Reed, M. R.

    2016-01-01

    Background Approximately half of all hip fractures are displaced intracapsular fractures. The standard treatment for these fractures is either hemiarthroplasty or total hip arthroplasty. The recent National Institute for Health and Care Excellence (NICE) guidance on hip fracture management recommends the use of ‘proven’ cemented stem arthroplasty with an Orthopaedic Device Evaluation Panel (ODEP) rating of at least 3B (97% survival at three years). The Thompsons prosthesis is currently lacking an ODEP rating despite over 50 years of clinical use, likely due to the paucity of implant survival data. Nationally, adherence to these guidelines is varied as there is debate as to which prosthesis optimises patient outcomes. Design This study design is a multi-centre, multi-surgeon, parallel, two arm, standard-of-care pragmatic randomised controlled trial. It will be embedded within the WHiTE Comprehensive Cohort Study (ISRCTN63982700). The main analysis is a two-way equivalence comparison between Hemi-Thompson and Hemi-Exeter polished taper with Unitrax head. Secondary outcomes will include radiological leg length discrepancy measured as per Bidwai and Willett, mortality, re-operation rate and indication for re-operation, length of index hospital stay and revision at four months. This study will be supplemented by the NHFD (National Hip Fracture Database) dataset. Discussion Evidence on the optimum choice of prosthesis for hemiarthroplasty of the hip is lacking. National guidance is currently based on expert opinion rather than empirical evidence. The incidence of hip fracture is likely to continue to increase and providing high quality evidence on the optimum Cite this article: A. L. Sims. The World Hip Trauma Evaluation Study 3: Hemiarthroplasty Evaluation by Multicentre Investigation – WHITE 3: HEMI – An Abridged Protocol. Bone Joint Res 2016;5:18–25. DOI: 10.1302/2046-3758.51.2000473 PMID:26825319

  14. Development of an Intelligent Spacer Data Logger System.

    PubMed

    O'Callaghan, Chris; Smith, Nicholas J; Barry, Peter W; Denyer, John

    2017-08-28

    Although delivery of drugs from pressurized metered dose inhalers (pMDIs) via spacer devices is widespread it cannot be assumed that patients take their medication as prescribed or use their spacer appropriately. We developed a Spacer Data Logger device to record patient adherence and whether patients had shaken the pMDI, actuated it soon after shaking, and inhaled a sufficient volume from it. We report an assessment of the Spacer Data Logger to measure and record that the pMDI was adequately shaken, the time to actuation, and the volume "inhaled" from the spacer up to 26 seconds after actuation. The effect of a delay in actuation following shaking on the dose available for inhalation from the spacer and the effect of a delay in extraction of aerosol from the spacer were assessed using different strengths of beclomethasone dipropionate (50 and 100 μg) and fluticasone propionate (50, 125 and 250 μg). The volumes measured by the Spacer Data Logger were in close agreement with the reference volumes of four simulated breathing patterns. A delay between shaking and actuating the pMDI resulted in a significant increase in the dose available for inhalation after only 4 seconds for the 50 and 250 μg strengths of fluticasone propionate pMDIs (p = 0.004 and p < 0.001, respectively). A delay between actuation of the drug into the spacer and "inhalation" of aerosol from the spacer also resulted in a steady decline in the dose available from the spacer (p < 0.0001). These results confirmed the importance of using the pMDI spacer correctly by actuating directly after shaking and inhaling the aerosol from the spacer as soon after actuation as possible to optimize the dose available for inhalation. The Spacer Data Logger should be a useful tool to determine adherence to and "optimum" use of pMDI spacers in patients with asthma and chronic obstructive pulmonary disease (COPD).

  15. Congenital hip disease in adults: terminology, classification, pre-operative planning and management.

    PubMed

    Karachalios, T; Hartofilakidis, G

    2010-07-01

    This paper reviews the current knowledge relating to the management of adult patients with congenital hip disease. Orthopaedic surgeons who treat these patients with a total hip replacement should be familiar with the arguments concerning its terminology, be able to recognise the different anatomical abnormalities and to undertake thorough pre-operative planning in order to replace the hip using an appropriate surgical technique and the correct implants and be able to anticipate the clinical outcome and the complications.

  16. [Modified Exeter technique in revision hip surgery].

    PubMed

    de Thomasson, E; Guingand, O; Terracher, R; Mazel, C

    2008-06-01

    The Exeter technique opened new perspectives for the treatment of femoral bone stock loss in revision hip arthroplasty. Implant migration in the cement sheath is, however, a frequent finding. According to the promoters of the technique, this would favor transformation of the allograft into living bone. For others it is a worrisome problem since it alters the heterogeneous cement sheath, leading to loosening and final surgical revision, with an incidence up to 20%. We propose an analysis of the mid-term results of the modified Exeter technique with the objective of cementing the distal part of the implant directly into the recipient bone in order to achieve satisfactory primary stability. The purpose of this work was to analyze the consequences of this method on the long-term evolution of the allograft. After preparing the femur, a specific gun is filled with allograph dough obtained from frozen femoral heads fragmented with an acetabular reamer. The Mersilene mesh enables the deposit of a tube of graft material at the desired level. The implant is sealed after impaction of the graft to enable direct distal cementing in contact with the recipient bone. Partial weight bearing is allowed as early as the fifth day and increased progressively to complete weight bearing at three months. Forty-five patients (46 hips) were treated between June 1996 and January 2002. Six patients were not retained for analysis due to insufficient follow-up. For three patients, graft outcome could not be properly assessed due to a major complication. In addition, two patients died and one was lost to follow-up. In all 39 patients (40 hips) were analyzed at mean follow-up of 84 months (range 48-110). There were no cases of revision for femoral loosening. Femoral bone loss was mainly moderate to severe type II and III hips (Sofcot classification) but limited in height (no grade IV in the Endo-Klinik classification). Clinical outcome was excellent in 13 hips, good in 16, fair in nine and poor

  17. Evaluation of Interspinous Spacer Outcomes in Degenerative Lumbar Canal Stenosis: Clinical Study.

    PubMed

    Abdel Ghany, Walid; Amer, Aboubakr; Saeed, Khaled; Emara, Essam; Hamad, Ahmad; Nosseir, Mohamed; Dawood, Osama; Nada, Mohamed A

    2016-11-01

    Lumbar spinal stenosis is a common diagnosis in elderly individuals, and the rates of surgery have risen all over the world. The optimal approach to provide satisfactory decompression and minimize complications for lumbar spinal stenosis remains controversial. The purpose of this study was to evaluate the surgical outcome of interspinous spacers versus decompressive laminectomy in the management of degenerative lumbar canal stenosis. Our prospective, comparative study included 2 groups of patients who were operated on in Ain Shams University Hospitals between January 2010 and December 2014. In the first group, 28 patients underwent decompression and additional implantation of an interspinous spacer (ISP). In the second group, 25 patients underwent decompressive laminectomy (DL). Our statistical results revealed no significant difference in outcome between the 2 groups regarding visual analog scale score for leg pain and Oswestry Low Back Pain Disability Index. However, the improvement (visual analog scale score) for back pain was better in the DL group. Complication and reoperation rates were higher in the ISP group. Although decompression and additional implantation of an ISP are safe procedures, they do not show better improvement in clinical outcome as compared with decompressive laminectomy. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Molecular recordings by directed CRISPR spacer acquisition.

    PubMed

    Shipman, Seth L; Nivala, Jeff; Macklis, Jeffrey D; Church, George M

    2016-07-29

    The ability to write a stable record of identified molecular events into a specific genomic locus would enable the examination of long cellular histories and have many applications, ranging from developmental biology to synthetic devices. We show that the type I-E CRISPR (clustered regularly interspaced short palindromic repeats)-Cas system of Escherichia coli can mediate acquisition of defined pieces of synthetic DNA. We harnessed this feature to generate records of specific DNA sequences into a population of bacterial genomes. We then applied directed evolution so as to alter the recognition of a protospacer adjacent motif by the Cas1-Cas2 complex, which enabled recording in two modes simultaneously. We used this system to reveal aspects of spacer acquisition, fundamental to the CRISPR-Cas adaptation process. These results lay the foundations of a multimodal intracellular recording device.

  19. Mask specification guidelines in spacer patterning technology

    NASA Astrophysics Data System (ADS)

    Hashimoto, Kohji; Mukai, Hidefumi; Miyoshi, Seiro; Yamaguchi, Shinji; Mashita, Hiromitsu; Kobayashi, Yuuji; Kawano, Kenji; Hirano, Takashi

    2008-11-01

    We have studied both the mask CD specification and the mask defect specification for spacer patterning technology (SPT). SPT has the possibility of extending optical lithography to below 40nm half-pitch devices. Since SPT necessitates somewhat more complicated wafer process flow, the CD error and mask defect printability on wafers involve more process factors compared with conventional single-exposure process (SEP). This feature of SPT implies that it is very important to determine mask-related specifications for SPT in order to select high-end mask fabrication strategies; those are for mask writing tools, mask process development, materials, inspection tools, and so on. Our experimental studies reveal that both mask CD specification and mask defect specification are somehow relaxed from those in ITRS2007. This is most likely because SPT reduces mask CD error enhanced factor (MEF) and the reduction of line-width roughness (LWR).

  20. Molecular recordings by directed CRISPR spacer acquisition

    PubMed Central

    Shipman, Seth L; Nivala, Jeff; Macklis, Jeffrey D; Church, George M

    2016-01-01

    The ability to write a stable record of identified molecular events into a specific genomic locus would enable the examination of long cellular histories and have many applications, ranging from developmental biology to synthetic devices. We show that the type I-E CRISPR-Cas system of E. coli can mediate acquisition of defined pieces of synthetic DNA. We harnessed this feature to generate records of specific DNA sequences into a population of bacterial genomes. We then applied directed evolution to alter the recognition of a protospacer adjacent motif by the Cas1-Cas2 complex, which enabled recording in two modes simultaneously. We used this system to reveal aspects of spacer acquisition, fundamental to the CRISPR-Cas adaptation process. These results lay the foundations of a multimodal intracellular recording device. PMID:27284167

  1. [Value of preoperative planning in total hip arthroplasty].

    PubMed

    De Thomasson, E; Mazel, C; Guingand, O; Terracher, R

    2002-05-01

    Preoperative planning enables an assessment of the size of the implants needed before total hip replacement. Eggli and Müller demonstrated the reproduciblity of preoperative planning but did not evaluate its contribution to reducing limb length discrepancy. As femur lateralization and the position of the prosthetic center of rotation affect joint mechanics, it would be useful to assess their contribution to the efficacy of preoperative planning. We reviewed the files of 57 patients who underwent total hip arthroplasty for primary joint degeneration or necrosis limited to one hip. The healthy hip served as a control. The surgical plan was elaborated from the preoperative pelvis x-rays (AP and lateral views) and anatomic measurements on films obtained three months postoperatively. In 49 cases, preoperative planning predicted a restoration of the normal anatomy of the operated hip (center of rotation, femur lateralization, length of the operated limb). This objective was achieved in only 22.5% of the cases. Femur lateralization was the most difficult objective to achieve (59.2%). Equal limb length and good position of the center of rotation was achieved in 70% of the cases. For eight patients (14%) preoperative planning was not satisfactory, the implant offset not being adapted to the patient's anatomy. There are limits to preoperative planning, particularly for restitution of adequate femur lateralization. This difficulty appears to be related to three factors: inadequate adaptation of the implant to hip anatomy (14% of the cases in our experience), stiff rotation in degenerative hips inhibiting proper assessment of the length of the femoral neck, and relative imprecision of operative evaluation of femoral anteversion affecting femur lateralization and the level of the femoral cut. Although imperfect, preoperative planning is, in our opinion, essential before total hip arthroplasty in order to avoid major positioning errors and operative difficulties.

  2. Targeting drugs to the airways: The role of spacer devices.

    PubMed

    Lavorini, Federico; Fontana, Giovanni A

    2009-01-01

    Spacer devices are inhalation aids of varying dimension and complexity, specifically designed to overcome problems with the use of pressurised metered dose inhalers (pMDIs). The aim of this review is to examine the current understanding about these inhalation devices and discuss their advantages and disadvantages. The pertinent literature concerning the characteristics and effects of spacers on delivery and lung deposition of inhaled medications, as well as their clinical efficacy in patients with reversible airway obstruction, is examined. Spacers minimise problems of poor inhalation technique with pMDI, reduce oropharyngeal deposition and increase lung deposition. Spacers improve the clinical effect of inhaled medications, especially in patients unable to use a pMDI properly. Compared to both pMDIs and dry-powder inhalers, spacers may increase the response to beta-adrenergic bronchodilators, even in patients with correct inhalation technique. A pMDI plus spacer has proven to be viable lower cost alternative to the use of a nebuliser for delivering large bronchodilator doses in patients with severe acute asthma or chronic obstructive pulmonary disease. The use of large-volume spacers is recommended for delivering high doses of inhaled corticosteroids, and may permit a lower maintenance dose to be used. pMDIs may be routinely fitted with a spacer, especially in situations where correct pMDI use is unlikely.

  3. Medical implants and methods of making medical implants

    DOEpatents

    Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug

    2014-09-16

    A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.

  4. Dementia and Hip Fractures

    PubMed Central

    Friedman, Susan M.; Menzies, Isaura B.; Bukata, Susan V.; Mendelson, Daniel A.; Kates, Stephen L.

    2010-01-01

    Dementia and hip fractures are 2 conditions that are seen primarily in older adults, and both are associated with substantial morbidity and mortality. An individual with dementia is up to 3 times more likely than a cognitively intact older adult to sustain a hip fracture. This may occur via several mechanisms, including (1) risk factors that are common to both outcomes; (2) the presence of dementia increasing hip fracture incidence via intermediate risk factors, such as falls, osteoporosis, and vitamin D; and (3) treatment of dementia causing side effects that increase hip fracture risk. We describe a model that applies these 3 mechanisms to explain the relationship between dementia and hip fractures. Comprehensive understanding of these pathways and their relative influence on the outcome of hip fracture will guide the development of effective interventions and potentially improve prevention efforts. PMID:23569663

  5. Migration analysis of a metaphyseal anchored short-stem hip prosthesis

    PubMed Central

    2012-01-01

    Background and purpose Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA). Patients and methods First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score. Results After 2.7 (2.0–4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3–1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0). [OK?] Interpretation The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement. PMID:22900913

  6. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  7. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  8. Hip fracture after hemiplegia.

    PubMed Central

    Mulley, G.; Espley, A. J.

    1979-01-01

    In a series of 57 hemiplegic patients who subsequently fractured their hips, it was found that hip fracture occurred significantly more often on the hemiplegic side. Hip fracture was equally common in right- and left-sided hemiplegia, and often occurred within one year of the stroke. Two factors seem to be important in the genesis of hip fractures in hemiplegic patients: the tendency of stroke patients to fall to the affected side as a result of impaired locomotor function, and the development of disuse osteoporosis in the hemiplegic limb. PMID:471862

  9. Influence of cementless cup surface on stability and bone fixation 2 years after total hip arthroplasty.

    PubMed

    Urbański, Wiktor; Krawczyk, Artur; Dragan, Szymon Ł; Kulej, Mirosław; Dragan, Szymon F

    2012-01-01

    Loss of fixation between bone and implant surface is one of the main treatment problems in total hip arthroplasty. It might lead to implant instability, bone loss and treatment failure resulting in revision surgery. Surface modification is a method for improving bone response to implant and increasing implant osseointegration. However, the currently applied modifications such as hydroxyapatite coatings do not meet expectation and do not provide good clinical result. The object of the study was to evaluate the influence of acetabular cup surface modification on fixation and bone remodelling in total hip arthroplasty. Clinical and radiological outcomes were evaluated in patients two years after cementless total hip replacement. Two groups were compared: patients with acetabular component with uncoated titanium surface and patients with hydroxyapatite-coated acetabular surface. Hips X-rays were analysed for early signs of losing stability of acetabular cups. Two years after surgery the analysis of X-rays did not reveal any statistical differences in stability, migration of acetabular components of endoprosthesis between both groups. No differences were also observed in bone remodelling around implants. Particularly high percentage of cups, i.e. 17.64%, were classified into the group with high risk of early implant loosening, i.e., the group with HA coatings. Hydroxyapatite coatings on titanium cementless acetabular cups implanted by press-fit technique have no influence on their stability, bone-implant fixation and the remodelling of bone surrounding an implant two years after surgery.

  10. A non-electrostatic spacer for aerosol delivery.

    PubMed Central

    Bisgaard, H; Anhøj, J; Klug, B; Berg, E

    1995-01-01

    A pear shaped non-electrostatic spacer, composed of steel with a volume of 250 ml and equipped with a facemask containing integrated inlet and outlet valves for inspiration and expiration, was compared with three plastic spacers. The plastic spacers were primed with repeated puffs from a budesonide pressurised metered dose inhaler (p-MDI) to minimise the electrostatic charge on the plastic. The procedure prolonged the half life (t1/2) of the aerosol in the Nebuhaler from nine to 32 seconds. A normal cleaning procedure reduced the aerosol t1/2 back to baseline. The t1/2 of the aerosol in the metal spacer was 27 seconds and independent of the use of p-MDI. In vitro the maximum dose of budesonide from a p-MDI, expressed as a percentage of the nominal dose, was 56% from the non-electrostatic spacer, 61% from the Nebuhaler, 45% from the Babyhaler, and 30% from the AeroChamber. In 124 children, age 6 months to 6 years, suspected to have asthma the non-electrostatic spacer delivered a mean total dose of budesonide aerosol of 39% of the nominal dose, which was significantly higher than the Babyhaler (28%), the Nebuhaler (21%), and the AeroChamber (19%). These differences were most pronounced in children younger than 4 years. The improved dose delivery from the small volume non-electrostatic spacer is probably related to the non-electrostatic spacer material and the valves which assured unidirectional airflow from the spacer without adding any dead space in the inspiratory channel. The non-electro-static spacer should improve the cost effectiveness of aerosol treatment and, as the counteracting effects of proming and recharging of the plastic from cleaning are avoided, should deliver a more reliable dose. PMID:7492160

  11. A Useful Anatomical Reference Guide for Stem Anteversion during Total Hip Arthroplasty in the Dysplastic Hip.

    PubMed

    Tsukeoka, Tadashi; Tsuneizumi, Yoshikazu; Lee, Tae Hyun

    2015-08-01

    Computed tomography scans of 50 dysplastic hips were obtained and reconstructed using preoperative planning software for total hip arthroplasty. The anteversion of the stem implanted parallel to the line connecting the trochanteric fossa and the middle of the medial cortex of the femoral neck (T line) was measured. The cutting heights of 5mm and 10mm above the lesser trochanter were simulated. The mean difference of the anteversion of the stem using the T line and the native femoral anteversion was 2.7° (95% CI: 1.0°-4.5°) and 3.5° (95% CI: 1.5°-5.5°) at cutting heights of 5mm and 10mm respectively. An anteversion using a T line is compatible with native femoral anteversion even in developmental dysplasia of the hip.

  12. Developmental Dysplasia of the Hip

    MedlinePlus

    ... is a problem with the way a baby's hip joint forms before, during, or after birth — causing an unstable hip. In severe cases, the hip joint can dislocate or cause trouble walking. Mild cases ...

  13. Transient Synovitis of the Hip

    MedlinePlus

    ... inflammation and swelling of the tissues around the hip joint. Usually only one hip is affected. This condition ... to reduce the swelling and inflammation around the hip joint.Your child's doctor will probably ask you to ...

  14. Penile Implants

    MedlinePlus

    Penile Implants Overview By Mayo Clinic Staff Penile implants are devices placed inside the penis to allow men with erectile dysfunction (ED) to get an erection. Penile implants are typically recommended after other treatments for ED ...

  15. [Survey on the use and behaviour of metal-metal hip replacements in Spain].

    PubMed

    Calcerrada, N; Fernández-Vega, A; Valls-León, C; Garcia-Cimbrelo, E

    2016-01-01

    Following medical device alerts published in different countries of problems with metal-on-metal total hip replacements, the Spanish Agency of Medicines and Medical Devices (AEMPS) in collaboration with the Spanish Hip Society Surgery designed a national survey to gather information on the use and behaviour of these hip implants. The survey consisted of a questionnaire sent by e-mail to 283 clinical centre recipients of metal-on-metal hips to be filled in by surgeons with expertise in the field. A total of 257 questionnaires were completed. The response rate of the clinical centres was 36.7%. A total of 97.7% of the responses reported that clinical and radiological follow-ups are carried out, and 79.6% undertook metal ion analyses (chromium and cobalt). A large majority (83.6%) of the responders who had who used surface implants, and 70% of those with large-head implants reported peri-operative complications. The most common complication was pain (25% with surface implants and 30.8% with large-head implants). Currently 80.8% of those responding were considering abandoning implanting of these hip replacements. Despite the many limitations to this study, the survey has allowed us to obtain in a quick first view of the implant scenario of Metal on Metal hip implants in Spain, and to determine the type of patient implanted, the time of implantation, and the experience/expertise of the surgeons, and the type of follow-up carried out. Copyright © 2015 SECOT. Published by Elsevier Espana. All rights reserved.

  16. Spacer effect on nanostructures and self-assembly in organogels via some bolaform cholesteryl imide derivatives with different spacers

    NASA Astrophysics Data System (ADS)

    Jiao, Tifeng; Gao, Fengqing; Zhang, Qingrui; Zhou, Jingxin; Gao, Faming

    2013-10-01

    In this paper, new bolaform cholesteryl imide derivatives with different spacers were designed and synthesized. Their gelation behaviors in 23 solvents were investigated, and some of them were found to be low molecular mass organic gelators. The experimental results indicated that these as-formed organogels can be regulated by changing the flexible/rigid segments in spacers and organic solvents. Suitable combination of flexible/rigid segments in molecular spacers in the present cholesteryl gelators is favorable for the gelation of organic solvents. Scanning electron microscopy and atomic force microscopy observations revealed that the gelator molecules self-assemble into different aggregates, from wrinkle and belt to fiber with the change of spacers and solvents. Spectral studies indicated that there existed different H-bond formations between imide groups and assembly modes, depending on the substituent spacers in molecular skeletons. The present work may give some insight into the design and character of new organogelators and soft materials with special molecular structures.

  17. Dental Implants.

    PubMed

    Griggs, Jason A

    2017-10-01

    Systematic reviews of literature over the period between 2008 and 2017 are discussed regarding clinical evidence for the factors affecting survival and failure of dental implants. The factors addressed include publication bias, tooth location, insertion torque, collar design, implant-abutment connection design, implant length, implant width, bone augmentation, platform switching, surface roughness, implant coatings, and the use of ceramic materials in the implant body and abutment. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The Role of Metal-on-Metal Bearings in Total Hip Arthroplasty and Hip Resurfacing: Review Article.

    PubMed

    Sands, David; Schemitsch, Emil H

    2017-02-01

    The current role of metal-on-metal (MoM) bearings in hip arthroplasty remains controversial. The low wear offered by MoM bearings compared to metal-on-polyethylene and the possibility of a lower risk of dislocation with larger head sizes, encouraged a trend towards the re-introduction of the MoM bearing couple. However, recent evidence has shown that not all designs of the MoM bearing have been successful. The purpose of this paper is to provide an update on the use of MoM bearings and address the following issues: (1) the reintroduction of metal-on-metal bearings in total hip arthroplasty, (2) the failure of metal-on-metal bearings in stemmed total hip arthroplasty, (3) the role of metal-on-metal hip resurfacing in modern orthopaedics and (4) metal-on-metal hip resurfacing versus total hip arthroplasty. A literature search strategy was conducted using various search terms in MEDLINE and Embase. The highest quality articles that met the inclusion criteria and best answered the topics of focus of this review were selected. Key search terms included 'metal-on-metal', 'total hip arthroplasty' and 'hip resurfacing'. The initial search retrieved 1240 articles. Twenty-two articles were selected and used in the review. Metal-on-metal hip resurfacing is still a suitable treatment option in specific patient populations with the appropriate implant design and surgical skill, while stemmed metal-on-metal total hip arthroplasty should be avoided in all patient populations. Continued follow-up of patients undergoing metal-on-metal hip resurfacing is critical in order to further understand the long-term outcomes of these patients and why certain complications tend to occur with this procedure.

  19. Evidence of MRSE on a gentamicin and vancomycin impregnated polymethyl-methacrylate (PMMA) bone cement spacer after two-stage exchange arthroplasty due to periprosthetic joint infection of the knee

    PubMed Central

    2014-01-01

    Background Periprosthetic joint infections (PJI) are often treated by two stage exchange with the use of an antibiotic impregnated spacer. Most of the two-stage exchange algorithms recommend the implantation of an antibiotic-impregnated spacer during the first stage for a period of 2–24 weeks before reimplantation of the new prosthesis. For the spacer to have a therapeutic effect, the local antibiotic concentration must be greater than the minimal inhibition concentration (MIC) against the pathogens causing the PJI. It must remain so for the entire spacer period, otherwise recurrence of infection or resistances might occur. The question as to whether a sufficient concentration of antibiotics in vivo is reached for the entire spacer period has not been answered satisfactorily. Case presentation We here present a case of a histologically confirmed chronic PJI 20 month after primary arthroplasty. The primary knee arthroplasty was performed due to osteoarthritis of the joint. Initial assessment did not detect a causative pathogen, and two stage exchange with a vancomycin-gentamycin impregnated spacer was performed. At the time of reimplantation, sonication of the explanted spacer revealed a multi-resistant strain of staphylococcus epidermidis on the device and in the joint. Adaption of the therapy and prolonged treatment successfully eradicated the infection. Conclusion According to the authors’ knowledge, the case presented here confirms for the first time the surface contamination (proven through sonication) of a vancomycin-/gentamicin- impregnated Vancogenx®-spacer with a MRSE after ten weeks of implantation. This case study demonstrates the difficulties still associated with the diagnostics of PJI and the published different two stage treatment regimes with the use of antibiotic impregnated spacers. PMID:24641471

  20. Lower limb length and offset in total hip arthroplasty.

    PubMed

    Flecher, X; Ollivier, M; Argenson, J N

    2016-02-01

    Restoration of normal hip biomechanics is a key goal of total hip arthroplasty (THA) and favorably affects functional recovery. Furthermore, a major concern for both the surgeon and the patient is preservation or restoration of limb length equality, which must be achieved without compromising the stability of the prosthesis. Here, definitions are given for anatomic and functional limb length discrepancies and for femoral and hip offset, determined taking anteversion into account. Data on the influence of operated-limb length and offset on patient satisfaction, hip function, and prosthesis survival after THA are reviewed. Errors may adversely impact function, quality of life, and prosthetic survival and may also generate conflicts between the surgeon and patient. Surgeons rely on two- or three-dimensional preoperative templating and on intraoperative landmarks to manage offset and length. Accuracy can be improved by using computer-assisted planning or surgery and the more recently introduced EOS imaging system. The prosthetic's armamentarium now includes varus-aligned and lateralized implants, as well as implants with modular or custom-made necks, which allow restoration of the normal hip geometry, most notably in patients with coxa vara or coxa valga. Femoral anteversion must also receive careful attention. The most common errors are limb lengthening and a decrease in hip offset. When symptoms are caused by an error in length and/or offset, revision arthroplasty may deserve consideration.

  1. Lesion of the hip abductor mechanism

    PubMed Central

    Caviglia, Horacio; Cambiaggi, Guillermo; Vattani, Nosrat; Landro, María Eulalia; Galatro, Gustavo

    2016-01-01

    Introduction: The disruption of the abductor muscles of the hip after hip revision surgery often causes limping, pain, and instability of the implant. The purpose of our paper is to describe a mesh technique to repair hip abductor mechanism injuries after hip revision. Patients and methods: Forty-six patients with hip abductor damage after prosthetic revision were treated. Inclusion criteria were: patients presenting with prosthetic loosening, complaint of pain, and with a positive Trendelenburg sign due to deficient abductor muscle mechanisms. Thirty-one were women (67.39%) with an average age of 64 years (34–82 years). The number of previous revision surgeries was three (two to seven). The Merle d’Aubigné score and variants before and after treatment were also reported. Results: In the postoperative follow-up after hip revision with the mesh technique, the Merle d’Aubigné score improved and the Trendelenburg sign was negative in 78.3% of the patients (p < 0.001). Also, the Trendelenburg test with the knee flexed was negative in 60.9% (p < 0.001) and the stair-climbing test was negative in 60.9% of cases (p < 0.001). The gluteus medius test in the lateral position was negative in 52.2% of patients, and in the lateral position with the knee flexed it was negative in 47.8% of patients (p < 0.001). Discussion: Repair of the abductor mechanism with the mesh technique has proven effective for both partial and total lesions. PMID:27382925

  2. Pervasive generation of oppositely oriented spacers during CRISPR adaptation.

    PubMed

    Shmakov, Sergey; Savitskaya, Ekaterina; Semenova, Ekaterina; Logacheva, Maria D; Datsenko, Kirill A; Severinov, Konstantin

    2014-05-01

    During the process of prokaryotic CRISPR adaptation, a copy of a segment of foreign deoxyribonucleic acid referred to as protospacer is added to the CRISPR cassette and becomes a spacer. When a protospacer contains a neighboring target interference motif, the specific small CRISPR ribonucleic acid (crRNA) transcribed from expanded CRISPR cassette can protect a prokaryotic cell from virus infection or plasmid transformation and conjugation. We show that in Escherichia coli, a vast majority of plasmid protospacers generate spacers integrated in CRISPR cassette in two opposing orientations, leading to frequent appearance of complementary spacer pairs in a population of cells that underwent CRISPR adaptation. When a protospacer contains a spacer acquisition motif AAG, spacer orientation that generates functional protective crRNA is strongly preferred. All other protospacers give rise to spacers oriented in both ways at comparable frequencies. This phenomenon increases the repertoire of available spacers and should make it more likely that a protective crRNA is formed as a result of CRISPR adaptation.

  3. Advanced hole patterning technology using soft spacer materials (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Park, Jong Keun; Hustad, Phillip D.; Aqad, Emad; Valeri, David; Wagner, Mike D.; Li, Mingqi

    2017-03-01

    A continuing goal in integrated circuit industry is to increase density of features within patterned masks. One pathway being used by the device manufacturers for patterning beyond the 80nm pitch limitation of 193 immersion lithography is the self-aligned spacer double patterning (SADP). Two orthogonal line space patterns with subsequent SADP can be used for contact holes multiplication. However, a combination of two immersion exposures, two spacer deposition processes, and two etch processes to reach the desired dimensions makes this process expensive and complicated. One alternative technique for contact hole multiplication is the use of an array of pillar patterns. Pillars, imaged with 193 immersion photolithography, can be uniformly deposited with spacer materials until a hole is formed in the center of 4 pillars. Selective removal of the pillar core gives a reversal of phases, a contact hole where there was once a pillar. However, the highly conformal nature of conventional spacer materials causes a problem with this application. The new holes, formed between 4 pillars, by this method have a tendency to be imperfect and not circular. To improve the contact hole circularity, this paper presents the use of both conventional spacer material and soft spacer materials. Application of soft spacer materials can be achieved by an existing coating track without additional cost burden to the device manufacturers.

  4. Treatment of periprosthetic femoral fractures following total hip arthroplasty with femoral component revision.

    PubMed

    Springer, Bryan D; Berry, Daniel J; Lewallen, David G

    2003-11-01

    Revision total hip arthroplasty is indicated for most periprosthetic fractures that occur around the stem of the femoral implant. The purpose of the present study was to assess the results and complications of revision total hip arthroplasty for the treatment of periprosthetic femoral fractures. We evaluated 118 hips in 116 patients who underwent revision total hip arthroplasty because of an acute Vancouver type-B periprosthetic femoral fracture. The femoral implant used for the revision was a cemented stem in forty-two hips, a proximally porous-coated uncemented stem in twenty-eight, an extensively porous-coated stem in thirty, and an allograft-prosthesis composite or tumor prosthesis in eighteen. The mean duration of follow-up was 5.4 years. Kaplan-Meier analysis demonstrated that the probability of survival was 90% at five years and 79.2% at ten years with revision or removal of the femoral implant for any reason as the end point. Sixteen femoral components were rerevised: ten were rerevised because of loosening; three, because of loosening in association with a fracture nonunion; two, because of recurrent dislocation; and one, because of a new periprosthetic fracture. Additionally, six femoral implants were resected because of deep infection (five) or prosthetic loosening (one). Radiographs of the ninety-six hips with a surviving implant showed that twenty-one had evidence of loosening of the femoral implant, four had a nonunion of the femoral fracture, and two had both a nonunion and loosening of the femoral implant. Revision total hip arthroplasty for the treatment of a periprosthetic fracture around the stem of the femoral implant successfully restored function for most patients. The greatest long-term problems were prosthetic loosening and fracture nonunion. Better results were seen when an uncemented, extensively porous-coated stem was used.

  5. Total Hip Arthroplasty for Hip Fractures

    PubMed Central

    Monzón, Daniel Godoy; Iserson, Kenneth V.; Jauregui, José; Musso, Carlos; Piccaluga, Francisco; Buttaro, Martin

    2014-01-01

    Introduction: This study aimed to determine the dislocation and reoperation rate, functional outcomes, and the survival rate of the unique subset of very old but lucid and independent patients with hip fractures following a total hip arthroplasty (THA) and geriatric team-coordinated perioperative care. Method: Between 2000 and 2006, previously independent ambulatory patients ≥80 years old presenting with an intracapsular hip fracture were given THAs under the care of an integrated orthopedic surgery–geriatric service. Their fracture-related complications, ambulation, mental status, and survival were followed for 5 to 11 years postinjury. Results: Five years postinjury, 57 (61.3%) patients of the original study group were living. In all, 3 (3.2%) patients had postoperative hip dislocations (and 2 patients had dislocation twice) and 2 reoperations were needed within the first postoperative month. There were no hip dislocations or reoperations after the first year. Radiographs obtained on 88% of the surviving patients at 5 years postoperatively showed that all remained unchanged from their immediate postoperative images. Nearly half of the patients were still able to ambulate as they did preoperatively and their mixed-model equation was statistically unchanged. Conclusion: This study of patients >80 years old with previously good functional status demonstrates that with appropriate surgical (best prosthesis, good operating technique, and regional anesthesia) and geriatric (pre- and postoperative assessments, close follow-up, medication adjustments, and fall-prevention instruction) care, they have few hip dislocations and reoperations, survive postfracture at least as long as their noninjured contemporaries, and continue to function and ambulate as they did prior to their injury. PMID:24660092

  6. Formed HIP Can Processing

    SciTech Connect

    Clarke, Kester Diederik

    2015-07-27

    The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.

  7. Current concepts, classification, and results in short stem hip arthroplasty.

    PubMed

    Falez, Francesco; Casella, Filippo; Papalia, Matteo

    2015-03-01

    Various short hip stems have been introduced with differing implant concepts of femoral fixation and implant length. There is a lack of proper classification for short hip stems, with a clear and accepted definition for implant length and extent of bone preservation in the metaphyseal and diaphyseal femur. This study analyzed the length of short hip stems. Stems were divided into collum, partial collum, and trochanter-sparing implants. An additional category was added, trochanter harming, which was defined as interruption of the circumferential integrity of the femoral neck. For all of the femoral components described, the designs were compared, excluding stems with insufficient clinical data. The 15 finally selected stems were classified as collum (1 stem), partial collum (7 stems), trochanter sparing (4 stems), and trochanter harming (3 stems). Mid-term results (>5 years of follow-up) were available for only 3 designs in the partial collum group. Taking into account the results of short-term studies (<5 years of follow-up), the femoral revision rate per 100 observed component years was <1 for most total hip arthroplasties. However, the studies varied greatly regarding level of significance, and short hip stems without published results are available commercially. Short hip stems cannot be circumscribed by a simple length limit. For some designs, clinical data collected from large patient cohorts showed a survivorship comparable to traditional stems. In cases that must be revised, this often can be performed with a conventional primary stem, fulfilling the promise to preserve bone for potential future revisions in younger patients. Copyright 2015, SLACK Incorporated.

  8. Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy

    SciTech Connect

    Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi

    2014-12-01

    Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field.

  9. Inhaler spacer devices to treat asthma in children.

    PubMed

    Watson, Paul

    Drawing on literature searches and professional experience, this article discusses the treatment of asthma with pressurised metered dose inhalers (pMDIs). It demonstrates the need for pMDIs, and presents the health and cost benefits of using a pMDI through a spacer device. Through the review and evaluation of studies, it demonstrates the importance of correct asthma management and the use of spacers. Although there are many types of spacer, and patients often have less than optimal technique, there is evidence to support the overall benefits of use against non-use.

  10. [Update on metal-on-metal hip joints].

    PubMed

    Günther, K-P; Lützner, J; Hannemann, F; Schmitt, J; Kirschner, S; Goronzy, J; Stiehler, M; Lohmann, C; Hartmann, A

    2013-05-01

    Increasing data are available describing risk factors for the development of local and systemic adverse events following operations using metal-on-metal (MoM) hip implants. The prevalence and clinical relevance of metal-associated problems are, however, still under debate. They can be influenced by type and position of implant as well as patient-specific factors. Patients with small MoM heads (maximum diameter 32 mm) and subgroups of resurfacing arthroplasty can achieve good long-term survival. The use of large head MoM implants (diameters greater than 36 mm), however, is currently not advised due to the unsatisfactory results.

  11. Numerical optimization of composite hip endoprostheses under different loading conditions

    NASA Technical Reports Server (NTRS)

    Blake, T. A.; Davy, D. T.; Saravanos, D. A.; Hopkins, D. A.

    1992-01-01

    The optimization of composite hip implants was investigated. Emphasis was placed on the effect of shape and material tailoring of the implant to improve the implant-bone interaction. A variety of loading conditions were investigated to better understand the relationship between loading and optimization outcome. Comparisons of the initial and optimal models with more complex 3D finite element models were performed. The results indicate that design improvements made using this method result in similar improvements in the 3D models. Although the optimization outcomes were significantly affected by the choice of loading conditions, certain trends were observed that were independent of the applied loading.

  12. [Hip dysplasia in adolescence].

    PubMed

    Barthès, X; Seringe, R

    1995-01-01

    Hip growth continues on till adolescence with the fusion of the different ossification centers. Does this growth exist in hip dysplasia? What is the role of surgery at adolescence? Is an additional varus osteotomy indicated with a pelvic osteotomy? Clinical and radiological criteria of adolescent hip dysplasia were studied in a series of 18 patients (mean age 12 years). The 28 hips were divided into 4 groups depending on the treatment: non operated hips (group 1, N = 8), hips operated on only by pelvic osteotomy (group 2, N = 8), hips operated on by combined pelvic and femoral osteotomies (group 3, N = 9), and hips operated on only by femoral osteotomy (group 4, N = 3). Tonnis's clinical criteria were used. The acetabular index of the weight bearing zone, the center-edge angle of Wiberg, the acetabular angle of Idelberger and Frank, the neck-shaft angle, the head coverage index were measured and compared between the 4 groups (average follow-up was 46 months). We noted continuation of growth of the acetabulum at adolescence with a correction of moderate hip dysplasia when the head was covered (group 1), the acetabular index of the weight-bearing zone decreased from 20.1 degrees to 11.1 degrees; the center-edge angle of Wiberg increased from 15.25 degrees to 23 degrees. The comparison of groups 2 and 3 showed that an additional femoral osteotomy does not change significantly the radiologic results. Does surgery benefit at adolescence from the growth which exists during this period? The clinical results and the evolution of arthrosis following a Chiari pelvic osteotomy are better when the operation is performed early. A pelvic osteotomy is indicated in symptomatic hips, when the congruity is abnormal, with deficient head coverage, as well as moderate dysplasia when the evolution of the acetabular parameters are not satisfactory. A femoral osteotomy in addition to a pelvic osteotomy does not seem justified.

  13. Pre-operative digital templating in cemented hip hemiarthroplasty for neck of femur fractures.

    PubMed

    Kwok, Iris H Y; Pallett, Scott J C; Massa, Edward; Cundall-Curry, Duncan; Loeffler, Mark D

    2016-03-01

    Pre-operative digital templating allows the surgeon to foresee any anatomical anomalies which may lead to intra-operative problems, and anticipate appropriate instruments and implants required during surgery. Although its role is well-established in successful elective total hip arthroplasty, little work has been done on its use in hip hemiarthroplasty in neck of femur fractures. We describe our initial experience of digital templating in 40 consecutive patients who have undergone cemented hip hemiarthroplasty, assessing templating accuracy between templated implant sizes to actual implant sizes. 81% of implanted heads were templated to within two head sizes, and 89% of implanted stems were templated to within two sizes. Although there was a moderately strong correlation of 0.52 between templated and actual head sizes, this correlation was not demonstrated in femoral stem sizes. Mean leg length discrepancy was -2.5mm (S.D. 8.5), and the mean difference in femoral offset between the operated and non-operated hip was -1mm (S.D. 4.4). Digital templating is a useful adjunct to the surgeon in pre-operative planning of hip hemiarthroplasty in the restoration of leg length and femoral offset. However, its accuracy is inferior to that of elective total hip arthroplasty. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Hip hemiarthroplasty: from Venable and Bohlman to Moore and Thompson.

    PubMed

    Hernigou, Philippe; Quiennec, Steffen; Guissou, Isaac

    2014-03-01

    In 1939, Frederick R. Thompson of New York and Austin T. Moore of South Carolina separately developed replacements for the entire ball of the hip. These were used to treat hip fractures and also certain arthritis cases. This type of hemiarthroplasty addressed the problem of the arthritic femoral head only. The diseased acetabulum (hip socket) was not replaced. This prosthesis consisted of a metal stem that was placed into the marrow cavity of the femur, connected in one piece with a metal ball fitted into the hip socket. Bohlman and Austin T. Moore (1939) collaborated for the fabrication and implantation of a custom made 12-inch-long vitallium (metal alloy invented by Venable) femoral head prosthesis for a patient with a recurrent giant cell tumour. This prosthesis functioned well and later on influenced the development of long stem femoral head prostheses.

  15. [Particle disease--aseptic loosening of the total hip endoprosthesis].

    PubMed

    Kolundzić, Robert; Orlić, Dubravko

    2008-01-01

    Total hip arthroplasty (THA) improves the ability and quality of life in patients with hip dysfunction due to different causes. Aseptic loosening is the major cause of the late hip endoprosthesis failure. It results from aseptic inflammatory reaction induced by the implant wear debris accumulating at the prosthesis interface, and is mediated by numerous cellular and humoral factors. Due to presence of wear debris we call aseptic loosening of the total hip endoprosthesis as "particle disease". In the most important of factors affecting the risk of aseptic instability include patient's age, sex, body mass index, underlying morbidity (reason for THA), endoprosthetic material and surgeon's skill. However, taken together, all these factors explain only a minor part of variability of this phenomenon. Factors that are decisive for the occurrence of aseptic instability are still largely unknown. The existence of "individual disposition" for development of aseptic instability that is not determined by demographic or biomechanical factors is well recognized.

  16. Hip arthroplasty. Part 1: prosthesis terminology and classification.

    PubMed

    Pluot, E; Davis, E T; Revell, M; Davies, A M; James, S L J

    2009-10-01

    Hip arthroplasty is an extremely common orthopaedic procedure and there is a wide array of implants that are in current use in the UK. The follow-up of patients who have undergone insertion of a hip prosthesis is shifting from a consultant-lead hospital service towards primary care. As this change in patient care continues it becomes increasingly important that an accurate description of the radiographic features is communicated to the primary-care practitioner so appropriate specialist input can be triggered. This review focuses on the terminology and classification of hip prostheses. This acts as a precursor for Part 2 of this series, which describes the normal and abnormal radiographic findings following hip prosthesis insertion.

  17. [Are the cobalt hip prosthesis dangerous?].

    PubMed

    Mistretta, Virginie; Kurth, William; Charlier, Corinne

    The placement of a hip prosthesis is one of the most common orthopedic surgical procedures. Some implants contain metal and are therefore capable of releasing metal particles like cobalt in patients who wear metal prostheses. Cobalt can be responsible of local toxicity (including metallosis, hypersensitivity reaction, and benign tumor) or systemic toxicity (including cardiomyopathy, polycythemia, hypothyroidism, and neurological disorders). To monitor potential toxicity of metal hip prostheses, an annual monitoring of patients implanted is recommended and includes clinical examination, radiological examination and blood cobalt determination. The cobalt concentration in blood allows to estimate the risk of toxicity and to evaluate the performance of the implant. The currently recommended threshold value is equal to 7 µg of cobalt per liter of blood. Our study, conducted on 251 patients over a period of 4 years, has shown that the cobalt concentration average was 2.51 µg/l in blood, with 51 patients having a cobaltemia higher than the threshold of 7 µg/l. © 2016 médecine/sciences – Inserm.

  18. The History of Biomechanics in Total Hip Arthroplasty.

    PubMed

    Houcke, Jan Van; Khanduja, Vikas; Pattyn, Christophe; Audenaert, Emmanuel

    2017-01-01

    Biomechanics of the hip joint describes how the complex combination of osseous, ligamentous, and muscular structures transfers the weight of the body from the axial skeleton into the appendicular skeleton of the lower limbs. Throughout history, several biomechanical studies based on theoretical mathematics, in vitro, in vivo as well as in silico models have been successfully performed. The insights gained from these studies have improved our understanding of the development of mechanical hip pathologies such as osteoarthritis, hip fractures, and developmental dysplasia of the hip. The main treatment of end-stage degeneration of the hip is total hip arthroplasty (THA). The increasing number of patients undergoing this surgical procedure, as well as their demand for more than just pain relief and leading an active lifestyle, has challenged surgeons and implant manufacturers to deliver higher function as well as longevity with the prosthesis. The science of biomechanics has played and will continue to play a crucial and integral role in achieving these goals. The aim of this article, therefore, is to present to the readers the key concepts in biomechanics of the hip and their application to THA.

  19. Prevention of hip fractures.

    PubMed

    Meunier, P J

    1993-11-30

    For a 50-year old Caucasian woman today, the risk of a hip fracture over her remaining life-time is about 17%. Tomorrow the situation will clearly be worse because the continuous increase in life expectancy will cause a three-fold increase in worldwide fracture incidence over the next 60 years. Through diagnostic bone mass measurements at the hip and assessment of biochemical parameters, a great deal has been learned in recent years about reduction of hip fracture risk. Preventive strategies are based on prevention of falls, use of hip protectors, and prevention of bone fragility. The latter includes the optimization of peak bone mass during childhood, postmenopausal estrogen replacement therapy, and also late prevention consisting in reversing senile secondary hyperparathyroidism, which plays an important role in the decrease of skeletal strength. This secondary hyperparathyroidism, which results from both vitamin D insufficiency and low calcium intake, is preventable with vitamin D3 and calcium supplements. They have recently been shown capable of providing effective prevention of hip fractures in elderly women living in nursing homes, with a reduction of about 25% in the number of hip fractures noted in a 3-year controlled study in 3,270 women (intention-to-treat analysis). In conclusion, it is never too early to reduce the risk of osteoporosis and never too late to prevent hip fractures.

  20. 14. TYPICAL WORK DECK SHOWING RING SPACERS, CABLE DRUMS AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. TYPICAL WORK DECK SHOWING RING SPACERS, CABLE DRUMS AND OTHER SPECIALIZED HARDWARE; VIEW TO SOUTH. - Cape Canaveral Air Station, Launch Complex 17, Facility 28416, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  1. Technique for adapting a spacer for a custom impression tray.

    PubMed

    Kaur, Harsimran; Nanda, Aditi; Verma, Mahesh; Koli, Dheeraj

    2016-12-01

    A method of adapting a spacer for the custom trays used to make a definite impression for complete dentures is presented. The technique can be used under a variety of conditions and offers several advantages.

  2. [Spinal column: implants and revisions].

    PubMed

    Krieg, S M; Meyer, H S; Meyer, B

    2016-03-01

    Non-fusion spinal implants are designed to reduce the commonly occurring risks and complications of spinal fusion surgery, e.g. long duration of surgery, high blood loss, screw loosening and adjacent segment disease, by dynamic or movement preserving approaches. This principle could be shown for interspinous spacers, cervical and lumbar total disc replacement and dynamic stabilization; however, due to the continuing high rate of revision surgery, the indications for surgery require as much attention and evidence as comparative data on the surgical technique itself.

  3. Lessons from retrievals: Retrievals help understand the reason for revision of coated hip arthroplasties.

    PubMed

    de Villiers, Danielle; Hothi, Harry; Khatkar, Harman; Meswania, Jayantilal; Blunn, Gordon; Skinner, John; Hart, Alister

    2015-11-01

    Coatings have been applied to all surfaces of hip implants with the majority performing well in the laboratory, but there are few reports of their performance in humans. The rationale for coating the metal-on-metal bearing surfaces includes a reduction in metal ion release and risk of adverse reaction to metal debris; yet there are no reports of retrieved coated metal-on-metal hip implants despite the concern that they may delaminate. The aim of this study was to better understand the performance of coated hip implants in humans through findings of three coated metal-on-metal hip resurfacings, retrieved after failure for unexplained pain. Analysis of these implants included quantification of the amount and mechanism of coating loss which was correlated with clinical, imaging and blood data. In all cases, there were large areas of complete coating loss in which the metal substrate was exposed and found to be rougher than the coated areas. The coating loss gave rise to third body abrasive wear of the coating and the exposed metal, the latter of which led to high blood levels of cobalt and chromium. Coating of the bearing surfaces of metal-on-metal hip resurfacings, therefore, do not prevent metal ion release when implanted into humans. This is an example of a need for increased retrieval analysis of newly introduced implants and expansion of laboratory testing regulations to better reflect the clinical environment.

  4. Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty.

    PubMed

    Masri, Bassam A; Panagiotopoulos, Kostas P; Greidanus, Nelson V; Garbuz, Donald S; Duncan, Clive P

    2007-01-01

    We retrospectively reviewed all patients at one center with an infected total hip arthroplasty treated with 2-stage revision using cementless components for the second stage and the PROSTALAC articulated spacer at the first stage. Twenty-nine patients were reviewed and followed for at least 2 years postoperatively. An isolated Staphylococcus species was cultured in 76% (22/29) of patients. Three (10.3%) of 29 patients had recurrent infection at the site of the prosthesis. One of the 3 patients ultimately underwent a Girdlestone arthroplasty. Another patient was managed with irrigation and debridement, whereas the final patient was treated with intravenous antibiotics alone. Treatment of infection at the site of a hip arthroplasty with 2-stage revision using cementless components and an articulated spacer yields recurrence rates similar to revisions where at least one of the components at the second stage is fixed with antibiotic-loaded cement.

  5. Improvement of pressurised aerosol deposition with Nebuhaler spacer device.

    PubMed Central

    Newman, S P; Millar, A B; Lennard-Jones, T R; Morén, F; Clarke, S W

    1984-01-01

    The effect on aerosol deposition from a pressurised metered dose inhaler of a 750 cm3 spacer device with a one way inhalation valve (Nebuhaler, Astra Pharmaceuticals) was assessed by means of an in vivo radiotracer technique. Nine patients with obstructive lung disease took part in the study. The pattern of deposition associated with use of a metered dose inhaler alone was compared with that achieved with the spacer used both for inhalation of single puffs of aerosol and for inhalation of four puffs actuated in rapid succession and then inhaled simultaneously. On each occasion there was a delay of 1 s between aerosol release and inhalation, simulating poor inhaler technique. With the metered dose inhaler alone, a mean (SEM) 8.7 (1.8)% of the dose reached the lungs and 80.9 (1.9)% was deposited in the oropharynx. With single puffs from the spacer 20.9 (1.6)% of the dose (p less than 0.01) reached the lungs, only 16.5 (2.3)% (p less than 0.01) was deposited in the oropharynx, and 55.8 (3.1)% was retained within the spacer itself. With four puffs from the spacer 15.2 (1.5)% reached the lungs (p = 0.02 compared with the metered dose inhaler alone, p less than 0.01 compared with single puffs from the spacer), 11.4 (1.2)% was deposited in the oropharynx, and 67.5 (1.8)% in the device itself. It is concluded that the spacer device gives lung deposition of metered dose aerosols comparable to or greater than a correctly used inhaler and oropharyngeal deposition is greatly reduced. The spacer should be used preferably for the inhalation of single puffs of aerosol but may also be used for the inhalation of up to four puffs actuated in rapid succession and then inhaled simultaneously. Images PMID:6440305

  6. Bioinformatics analyses of Shigella CRISPR structure and spacer classification.

    PubMed

    Wang, Pengfei; Zhang, Bing; Duan, Guangcai; Wang, Yingfang; Hong, Lijuan; Wang, Linlin; Guo, Xiangjiao; Xi, Yuanlin; Yang, Haiyan

    2016-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are inheritable genetic elements of a variety of archaea and bacteria and indicative of the bacterial ecological adaptation, conferring acquired immunity against invading foreign nucleic acids. Shigella is an important pathogen for anthroponosis. This study aimed to analyze the features of Shigella CRISPR structure and classify the spacers through bioinformatics approach. Among 107 Shigella, 434 CRISPR structure loci were identified with two to seven loci in different strains. CRISPR-Q1, CRISPR-Q4 and CRISPR-Q5 were widely distributed in Shigella strains. Comparison of the first and last repeats of CRISPR1, CRISPR2 and CRISPR3 revealed several base variants and different stem-loop structures. A total of 259 cas genes were found among these 107 Shigella strains. The cas gene deletions were discovered in 88 strains. However, there is one strain that does not contain cas gene. Intact clusters of cas genes were found in 19 strains. From comprehensive analysis of sequence signature and BLAST and CRISPRTarget score, the 708 spacers were classified into three subtypes: Type I, Type II and Type III. Of them, Type I spacer referred to those linked with one gene segment, Type II spacer linked with two or more different gene segments, and Type III spacer undefined. This study examined the diversity of CRISPR/cas system in Shigella strains, demonstrated the main features of CRISPR structure and spacer classification, which provided critical information for elucidation of the mechanisms of spacer formation and exploration of the role the spacers play in the function of the CRISPR/cas system.

  7. Nuclear ribosomal spacer regions in plant phylogenetics: problems and prospects.

    PubMed

    Poczai, Péter; Hyvönen, Jaakko

    2010-04-01

    The nuclear ribosomal locus coding for the large subunit is represented in tandem arrays in the plant genome. These consecutive gene blocks, consisting of several regions, are widely applied in plant phylogenetics. The regions coding for the subunits of the rRNA have the lowest rate of evolution. Also the spacer regions like the internal transcribed spacers (ITS) and external transcribed spacers (ETS) are widely utilized in phylogenetics. The fact, that these regions are present in many copies in the plant genome is an advantage for laboratory practice but might be problem for phylogenetic analysis. Beside routine usage, the rDNA regions provide the great potential to study complex evolutionary mechanisms, such as reticulate events or array duplications. The understanding of these processes is based on the observation that the multiple copies of rDNA regions are homogenized through concerted evolution. This phenomenon results to paralogous copies, which can be misleading when incorporated in phylogenetic analyses. The fact that non-functional copies or pseudogenes can coexist with ortholougues in a single individual certainly makes also the analysis difficult. This article summarizes the information about the structure and utility of the phylogenetically informative spacer regions of the rDNA, namely internal- and external transcribed spacer regions as well as the intergenic spacer (IGS).

  8. Nuclear reactor spacer grid and ductless core component

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.

    1989-01-01

    The invention relates to a nuclear reactor spacer grid member for use in a liquid cooled nuclear reactor and to a ductless core component employing a plurality of these spacer grid members. The spacer grid member is of the egg-shell type and is constructed so that the walls of the cell members of the grid member are formed of a single thickness of metal to avoid tolerance problems. Within each cell member is a hydraulic spring which laterally constrains the nuclear material bearing rod which passes through each cell member against a hardstop in response to coolant flow through the cell member. This hydraulic spring is also suitable for use in a water cooled nuclear reactor. A core component constructed of, among other components, a plurality of these spacer grid members, avoids the use of a full length duct by providing spacer sleeves about the sodium tubes passing through the spacer grid members at locations between the grid members, thereby maintaining a predetermined space between adjacent grid members.

  9. The evolution of spacers and valved holding chambers.

    PubMed

    Nikander, Kurt; Nicholls, Clare; Denyer, John; Pritchard, John

    2014-08-01

    Spacers and valved holding chambers (VHCs) are pressurized metered dose inhaler (pMDI) accessory devices, designed to overcome problems that patients commonly experience when administering aerosol via a pMDI. Spacers were developed in direct response to patient-related issues with pMDI technique, particularly, poor coordination between actuation and inhalation, and local side-effects arising from oropharyngeal deposition. Current clinical guidelines indicate the need for widespread prescription and use of spacers, but, despite their apparent ubiquity, the devices themselves are, unfortunately, all too commonly "disused" by patients. An understanding of the background from which spacers developed, and the key factors influencing the optimization of the spacer and the later VHC, is crucial to developing an appreciation of the potential of these devices, both contemporary and future, for improving the delivery of pressurized aerosols to patients. This review, informed by a full patent search and an extensive scientific literature review, takes into account the clinical and laboratory evidence, commercial developments, and the sometimes serendipitous details of scientific anecdotes to form a comprehensive perspective on the evolution of spacers, from their origins, in the early days of the pMDI, up to the present day.

  10. Sidewall spacer optimization for steep switching junctionless transistors

    NASA Astrophysics Data System (ADS)

    Gupta, Manish; Kranti, Abhinav

    2016-06-01

    In this work, we analyze the impact of a high permittivity (high-κ) sidewall spacer and gate dielectric on the occurrence of sub-60 mV/decade subthreshold swing (S-swing) in symmetrical junctionless (JL) double gate (DG) transistors. It is shown that steep S-swing values (≤10 mV/decade) can be achieved in JL devices with a combination of a high permittivity (high-κ) gate dielectric and a narrow low permittivity (low-κ) sidewall spacer. Implementation of a wider high-κ spacer will diminish the degree of impact ionization by the influence of the fringing component of the gate electric field, and will not be useful for steep off-to-on current transition. A wider spacer with low-κ and a narrow spacer with high-κ permittivity will be useful to limit the latching effect that can occur at lower temperatures (250 K). For high temperature operation, the decrease in the impact ionization rate can be compensated by designing a JL transistor with a thicker silicon film. The work demonstrates opportunities to enhance impact ionization at sub bandgap voltages, and proposes optimal guidelines for selecting a sidewall spacer to facilitate steep switching in JL transistors.

  11. Novel spacer device does not improve adherence in childhood asthma.

    PubMed

    Burgess, S W; Sly, P D; Cooper, D M; Devadason, S G

    2007-08-01

    The Funhaler (FH) is a novel spacer device (holding chamber) that has been designed to improve adherence and aerosol delivery in young asthmatic children using a metered dose inhaler. A pilot study reported a 38% increase in parent-reported adherence over 2 weeks compared with the child's normal spacer. The aim of this study was to investigate whether the FH would be associated with superior adherence in the medium term (3 months) using an objective assessment. Forty-seven children aged 18 months to 7 years were randomised to a FH or control small volume spacer. Participants were reviewed monthly for 3 months. Adherence was measured using an electronic monitoring device (Smartinhaler). Disease control was based on symptom scores and exacerbation rates. Twenty-six children were randomised to the FH and 21 to the control spacer. Three children withdrew (FH = 2). Median adherence each month for the 3 months was 74%, 54%, and 46% for the FH and 70%, 73%, and 54% for the control spacer. The difference in adherence was not statistically significant (P = 0.47, 0.37, and 0.23, respectively). There was also no significant difference in exacerbation rates or symptom scores. Seven of the FHs broke during the study. The FH was preferred by 21/24 parents randomised to the FH compared with their child's normal spacer. Despite the FH being popular with children and parents its use was not associated with improved adherence or disease control. 2007 Wiley-Liss, Inc.

  12. Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures

    PubMed Central

    2014-01-01

    Background Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. Methods/Design FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. Discussion This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. Trial registration The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813). PMID:24965132

  13. Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures.

    PubMed

    2014-06-26

    Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813).

  14. Digital templating in total hip arthroplasty: Additional anteroposterior hip view increases the accuracy

    PubMed Central

    Stigler, Sophia K; Müller, Franz J; Pfaud, Sebastian; Zellner, Michael; Füchtmeier, Bernd

    2017-01-01

    AIM To analyze planning total hip arthroplasty (THA) with an additional anteroposterior hip view may increases the accuracy of preoperative planning in THA. METHODS We conducted prospective digital planning in 100 consecutive patients: 50 of these procedures were planned using pelvic overview only (first group), and the other 50 procedures were planned using pelvic overview plus antero-posterior (a.p.) hip view (second group). The planning and the procedure of each patient were performed exclusively by the senior surgeon. Fifty procedures with retrospective analogues planning were used as the control group (group zero). After the procedure, the planning was compared with the eventually implanted components (cup and stem). For statistic analysis the χ2 test was used for nominal variables and the t test was used for a comparison of continuous variables. RESULTS Preoperative planning with an additional a.p. hip view (second group) significantly increased the exact component correlation when compared to pelvic overview only (first group) for both the acetabular cup and the femoral stem (76% cup and 66% stem vs 54% cup and 32% stem). When considering planning ± 1 size, the accuracy in the second group was 96% (48 of 50 patients) for the cup and 94% for the stem (47 of 50 patients). In the analogue control group (group zero), an exact correlation was observed in only 1/3 of the cases. CONCLUSION Digital THA planning performed by the operating surgeon and based on additional a.p. hip view significantly increases the correlation between preoperative planning and eventual implant sizes. PMID:28144576

  15. Transient osteoporosis of the hip.

    PubMed

    McWalter, Patricia; Hassan, Ahmed

    2009-01-01

    Transient osteoporosis of the hip is an uncommon cause of hip pain, mostly affecting healthy middle-aged men and also women in the third trimester of pregnancy. We present a case of transient osteoporosis of the hip in a 33-year-old non-pregnant female patient. This case highlights the importance of considering a diagnosis of transient osteoporosis of the hip in patients who present with hip pain.

  16. Hip arthroscopy in the setting of hip dysplasia

    PubMed Central

    Yeung, M.; Kowalczuk, M.; Simunovic, N.

    2016-01-01

    Objective Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia. Methods A systematic search was performed in duplicate for studies investigating the outcome of hip arthroscopy in the setting of hip dysplasia up to July 2015. Study parameters including sample size, definition of dysplasia, outcomes measures, and re-operation rates were obtained. Furthermore, the levels of evidence of studies were collected and quality assessment was performed. Results The systematic review identified 18 studies investigating hip arthroscopy in the setting of hip dysplasia, with 889 included patients. Criteria used by the studies to diagnose hip dysplasia and borderline hip dysplasia included centre edge angle in 72% of studies but the range of angles were quite variable. Although 89% of studies reported improved post-operative outcome scores in the setting of hip dysplasia, revision rates were considerable (14.1%), with 9.6% requiring conversion to total hip arthroplasty. Conclusion The available orthopaedic literature suggests that although improved outcomes are seen in hip arthroscopy in the setting of hip dysplasia, there is a high rate of re-operation and conversion to total hip arthroplasty. Furthermore, the criteria used to define hip dysplasia vary considerably among published studies. Cite this article: M. Yeung, M. Kowalczuk, N. Simunovic, O. R. Ayeni. Hip arthroscopy in the setting of hip dysplasia: A systematic review. Bone Joint Res 2016;5:225–231. DOI: 10.1302/2046-3758.56.2000533. PMID:27313136

  17. [Epidemiology of hip fracture].

    PubMed

    Hagino, Hiroshi

    2006-12-01

    Age- and gender-specific numbers of patients with hip fracture increase with age and peaked at the age 80-84; however, age- and gender-specific incidences increase exponentially with age. According to the recent nation-wide survey, the most common cause of hip fractures was a simple fall, 68.8% sustained fractures in-doors, and the incidences were higher in the winter than the summer period. More than 90% of patients with hip fracture were treated surgically and about 3/4 of patients with femoral neck fractures were treated with hemi-arthroplasty. Hip fractures for Asian people including Japanese are lower than those for Caucasians living in Northern Europe and North America; however, recent reports from the Asian area indicated an increase in the incidence with time.

  18. Minimally invasive hip replacement

    MedlinePlus

    ... muscles around the hip are cut or detached. Description To perform this surgery: A cut will be ... 30 centimeters) long. The surgeon will use special instruments to work through the small cut. Surgery involves ...

  19. Ultrasound: Infant Hip

    MedlinePlus

    ... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...

  20. HIP osteoarthritis and work.

    PubMed

    Harris, E Clare; Coggon, David

    2015-06-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by the elimination or redesign of processes and the use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on the capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment.

  1. Ultrasound: Infant Hip

    MedlinePlus

    ... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...

  2. Hip joint replacement

    MedlinePlus

    ... A socket, which is usually made of strong metal. A liner, which fits inside the socket. It ... are now trying other materials, like ceramic or metal. The liner allows the hip to move smoothly. ...

  3. HIP OSTEOARTHRITIS AND WORK

    PubMed Central

    Harris, E Clare; Coggon, David

    2016-01-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by elimination or redesign of processes and use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age, and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  4. Effect of soft-tissue impingement on range of motion during posterior approach Total Hip Arthroplasty: an in vivo measurement study.

    PubMed

    Nakamura, Nobuo; Maeda, Yuki; Hamawaki, Makoto; Sakai, Takashi; Sugano, Nobuhiko

    2016-12-01

    While implant impingement and bony impingement have been recognized as causes of poor outcomes in total hip arthroplasty (THA), reports of soft-tissue impingement are rare. To clarify the issue, the effect of anterior capsule resection on hip range of motion (ROM) was quantitatively measured in vivo during posterior approach THA using a CT-based hip navigation system. For 47 patients (51 hips), hip ROM was measured intraoperatively before and after resection of the anterior hip capsule, and the difference was compared. Resection of the anterior hip capsule brought about an average 6° increase of ROM in the direction of flexion with internal rotation and did not markedly change ROM in other directions. During THA through a posterior approach, soft-tissue impingement by the anterior hip capsule can occur. Clinically, we expect that resection of the anterior hip capsule can reduce the risk of posterior instability without increasing the risk of anterior instability.

  5. The treatment of the infected hip replacement. The complex case.

    PubMed

    Haddad, F S; Masri, B A; Garbuz, D S; Duncan, C P

    1999-12-01

    The treatment of the infected total hip replacement remains expensive, leads to a long difficult course for the patient, and frequently results in a suboptimal functional outcome. Various treatment techniques are available, and may be suitable for the more straightforward case. These include one-stage exchange arthroplasty, two-stage exchange arthroplasty, resection arthroplasty, and debridement and irrigation. The complex infected total hip replacement encompasses numerous host and organism factors. These include unusual or multiple organisms, diagnostic difficulties, bone loss, immunocompromise, and reinfection. In the authors' experience, the problem of the complex infected hip replacement is best addressed using the prosthesis of antibiotic-loaded acrylic cement approach. This interval arthroplasty is a modular, custom-made, immediate fit, antibiotic selective, temporary spacer system that allows the surgeon to reconstruct even the most deficient bone stock safely and effectively using two-stage exchange arthroplasty. It affords the patient rapid pain relief, allows them to mobilize quickly while successfully eradicating infection in 96% of hips with severe bone loss, and sets an appropriate soft tissue environment for a relatively straightforward second stage procedure. The prosthesis of antibiotic-loaded acrylic cement system affords the benefits of two-stage exchange without the functional disadvantages of an excision arthroplasty particularly when the proximal femur is severely deficient. It allows flexibility for the interval period and the type of fixation used, and the potential for allograft reconstruction at the final stage.

  6. Hip fusion as hip salvage procedure in cerebral palsy.

    PubMed

    Fucs, Patricia M De Moraes Barros; Yamada, Helder H

    2014-01-01

    The treatment of the spastic hip in Cerebral Palsy (CP) remains a challenge especially in cases of advance changes. Many options are available and the key for a good outcome is to find the best surgical procedure to an individualized patient. The hip fusion is one of the surgical options. The authors presented a group of spastic CP with painful chronic hip subluxation and dislocation treated with hip fusion with a mean follow-up period of 14.5 years. Surgical technique, post-operative management and outcomes were shown, also with the observations done regarding the evolution of the contralateral hip after the hip fusion. They concluded that the hip arthrodesis is an option for patients with spastic CP with painful subluxation or dislocated hips with the goal of pain relief maintain or improve functional status, and facilitating the care. The best candidate is a young ambulatory patient with normal contralateral hip and normal spinal alignment.

  7. Fracture of the Modular Neck in Total Hip Arthroplasty

    PubMed Central

    Hernandez, A.; Gargallo-Margarit, A.; Barro, V.; Gallardo-Calero, I.; Sallent, A.

    2015-01-01

    Modularity of the components in total hip arthroplasty has had an increase in popularity in the last decades. We present the case of a 53-year-old man with a history of avascular necrosis of the femoral head due to a hypophyseal adenoma. A total hip modular arthroplasty was implanted. Three and a half years after the surgery the patient attended the emergency room due to acute left hip pain with no prior traumatism. Radiological examination confirmed a fracture of the modular neck. A revision surgery was performed finding an important pseudotumoral well-organized periprosthetic tissue reaction. Through an extended trochanteric osteotomy the femoral component was removed, and a straight-stem revision prosthesis implanted. There are several potential advantages when using modularity in total hip arthroplasty that surgeons may benefit from, but complications have arisen and must be addressed. Various circumstances such as large femoral head with a long varus neck, corrosion, patient's BMI, and activity level may participate in creating the necessary environment for fatigue failure of the implant. PMID:26266069

  8. Ultrasonography of the hip.

    PubMed

    Nestorova, Rodina; Vlad, Violeta; Petranova, Tzvetanka; Porta, Francesco; Radunovic, Goran; Micu, Mihaela C; Iagnocco, Annamaria

    2012-09-01

    A complete physical examination of the hip is often difficult due to its size and deep position. During the last two decades, ultrasonography (US) of the hip has been widely accepted as a useful diagnostic tool in patients with hip pain and /or limited range of motion. It is commonly used in both adults and children. This technique allows evaluation of different anatomical structures and their pathological changes, such as joint recess (joint effusion, synovial hypertrophy), changes within the bursae (bursitis), tendons and muscles (tendinopathy, ruptures, calcifications), as well as changes in the bony profile of the joint surfaces, ischial tuberosity, and greater trochanter (erosions, osteophytes, calcific deposits). US is very useful for guided procedures in hip joint and periarticular soft tissues under direct visualization. The needle aspiration of synovial fluid and steroid injections are commonly-applied activities in daily rheumatology practice. The relatively limited acoustic windows available to the US beam are the principal limitations to hip US. Therefore, conducting a detailed examination of some important structures together with the interpretation of Doppler signal (sometimes undetectable) is not easy, requiring good knowledge of the modality. The aim of this review is to analyze the current literature about US of the hip and to describe the most frequently-observed normal and pathological findings.

  9. HIP ARTHROSCOPY IN ATHLETES

    PubMed Central

    Polesello, Giancarlo Cavalli; Keiske Ono, Nelson; Bellan, Davi Gabriel; Honda, Emerson Kiyoshi; Guimarães, Rodrigo Pereira; Junior, Walter Riccioli; Do Val Sella, Guilherme

    2015-01-01

    To confirm the therapeutic importance of hip arthroplasty in athletes whose pain precludes sportive function of the hip joint, being able to minimize it to the extent of helping on the return of sports practice at satisfactory levels. Methods: 49 athlete patients (51 hips) submitted to hip arthroscopy complaining of pain and inability to practice sports were assessed. Follow-up time ranged from 12 to 74 months (mean: 39.0 months). Preoperatively, pain site, severity according to Facial Expression Scale (FES) and the degree of disability using the modified Harris Hip Score (HHS) were assessed. Different diagnoses were provided, which led to the indication of arthroscopy, such as femoralacetabular impact, acetabular lip injury not secondary to femoral-acetabular impact, etc. Postoperatively, the patients were assessed by using the same methods as used at baseline and by the subjective analysis of return to sports activities. Results: Based on pre-and postoperative HHS and FES, the statistical analysis showed significance between values. We found some improvement in all cases and return to sports activities at a satisfactory level in most of the cases. Conclusion: As a result of our study, we confirm that arthroscopy in athletes with local hip injuries is an effective technique, able to promote the return to sports practice in most of the cases, without pain, and with an effective joint function, provided well indicated. PMID:26998449

  10. Allergic or Hypersensitivity Reactions to Orthopaedic Implants.

    PubMed

    Roberts, Timothy T; Haines, Colin M; Uhl, Richard L

    2017-10-01

    Allergic or hypersensitivity reactions to orthopaedic implants can pose diagnostic and therapeutic challenges. Although 10% to 15% of the population exhibits cutaneous sensitivity to metals, deep-tissue reactions to metal implants are comparatively rare. Nevertheless, the link between cutaneous sensitivity and clinically relevant deep-tissue reactions is unclear. Most reactions to orthopaedic devices are type IV, or delayed-type hypersensitivity reactions. The most commonly implicated allergens are nickel, cobalt, and chromium; however, reactions to nonmetal compounds, such as polymethyl methacrylate, antibiotic spacers, and suture materials, have also been reported. Symptoms of hypersensitivity to implants are nonspecific and include pain, swelling, stiffness, and localized skin reactions. Following arthroplasty, internal fixation, or implantation of similarly allergenic devices, the persistence or early reappearance of inflammatory symptoms should raise suspicions for hypersensitivity. However, hypersensitivity is a diagnosis of exclusion. Infection, as well as aseptic loosening, particulate synovitis, instability, and other causes of failure must first be eliminated.

  11. Reducing electrostatic charge on spacer devices and bronchodilator response

    PubMed Central

    Wildhaber, Johannes H; Waterer, Grant W; Hall, Graham L; Summers, Quentin A

    2000-01-01

    Aims Plastic spacers are widely used with pressurized metered dose inhalers (pMDI). Reducing electrostatic charge by washing spacers with detergent has been shown to greatly improve in vitro and in vivo drug delivery. We assessed whether this finding is associated with an improved bronchodilator response in adult asthmatics. Methods Twenty subjects (age 18–65 years) with a known bronchodilator response inhaled in random order salbutamol from a pMDI (Ventolin®) through an untreated new spacer (Volumatic®) and through a detergent washed spacer. Patients received the following doses of salbutamol via pMDI at 20 min intervals: 100 µg, 100 µg, 200 µg, 400 µg, 800 µg. Spirometry, heart rate and blood pressure were checked prior to each dose and 20 min after the last dose. Results There were no differences between baseline forced expiratory volume in 1 s (FEV1) using either spacer (2.61 ± 0.56 and 2.52 ± 0.45 l, untreated and treated with detergent, respectively; mean ±s.d.). The provocation dose required to cause a clinically significant improvement of 10% in FEV1 (PD10) was significantly lower when the detergent treated spacer was used (1505 ± 1335 and 430 ± 732 µg, untreated and treated, respectively, P < 0.002). Conclusions We have demonstrated an improvement in bronchodilator response, in adult asthmatics, after reducing the electrostatic charge in a spacer device by washing it with ordinary household detergent. This finding stresses the importance of an optimal choice of delivery device for asthma medication. PMID:10971314

  12. The use of porous polyethylene (Medpor) lower eyelid spacers in lid heightening and stabilisation

    PubMed Central

    Tan, J; Olver, J; Wright, M; Maini, R; Neoh, C; Dickinson, A J

    2004-01-01

    Background/aims: The management of lower eyelid retraction can be challenging, and established techniques to correct it are not always successful. Previous reports have suggested a role for the ultrathin high density porous polyethylene lower eyelid spacer (Medpor LES) in such patients. The authors report the experience of three surgeons implanting Medpor LES over 1 year, and ascertain whether such implants are a safe and effective alternative to autogenous spacers. Methods: A prospective, interventional, non-comparative case series of consecutive patients. Surgical indications for Medpor LES were noted. Preoperative and postoperative lower marginal reflex distance (L-MRD), vertical palpebral aperture (PA), lagophthalmos, and scleral show inferior to the limbus (LSS) were recorded, together with major and minor complications. Results: 32 patients (35 eyelids) had a Medpor LES inserted, 22/32 under local anaesthetic, and nine with adjunctive procedures. Mean follow up was 22 months (range 15–28 months). The Medpor LES was effective in reducing the palpebral aperture (p<0.001) and lagophthalmos (p = 0.04) and raising the lower eyelid height by reducing both L-MRD (p  =  0.006) and LSS (p<0.001). However there were major complications in 7/32 patients and minor complications in 8/32, most requiring further surgery. Final outcome was good in 24/35 eyelids and satisfactory in 5/35. Conclusions: Despite a good or satisfactory final outcome in the majority of patients, the value of this technique is limited by complications, and should be reserved for those unsuitable for safer techniques. PMID:15317715

  13. The use of porous polyethylene (Medpor) lower eyelid spacers in lid heightening and stabilisation.

    PubMed

    Tan, J; Olver, J; Wright, M; Maini, R; Neoh, C; Dickinson, A J

    2004-09-01

    The management of lower eyelid retraction can be challenging, and established techniques to correct it are not always successful. Previous reports have suggested a role for the ultrathin high density porous polyethylene lower eyelid spacer (Medpor LES) in such patients. The authors report the experience of three surgeons implanting Medpor LES over 1 year, and ascertain whether such implants are a safe and effective alternative to autogenous spacers. A prospective, interventional, non-comparative case series of consecutive patients. Surgical indications for Medpor LES were noted. Preoperative and postoperative lower marginal reflex distance (L-MRD), vertical palpebral aperture (PA), lagophthalmos, and scleral show inferior to the limbus (LSS) were recorded, together with major and minor complications. 32 patients (35 eyelids) had a Medpor LES inserted, 22/32 under local anaesthetic, and nine with adjunctive procedures. Mean follow up was 22 months (range 15-28 months). The Medpor LES was effective in reducing the palpebral aperture (p<0.001) and lagophthalmos (p = 0.04) and raising the lower eyelid height by reducing both L-MRD (p = 0.006) and LSS (p<0.001). However there were major complications in 7/32 patients and minor complications in 8/32, most requiring further surgery. Final outcome was good in 24/35 eyelids and satisfactory in 5/35. Despite a good or satisfactory final outcome in the majority of patients, the value of this technique is limited by complications, and should be reserved for those unsuitable for safer techniques.

  14. [Surgical treatment of hip osteoarthritis: hpdete on hip arthroscopy].

    PubMed

    Ilizaliturri Sánchez, Víctor M; Camacho Galindo, Javier

    2007-10-01

    Arthroscopic surgery of the hip is a routine procedure in an increasing number of institutions around the world. Indications for this procedure increase as more experience is developed. Thanks to hip arthroscopy some intraarticular lesions like labral or ligamentum teres tears and cartilage lesions have been recognized. All of these have the potential to develop hip osteoarthritis. Open techniques for the treatment of femoroacetabular impingement have been transformed to arthroscopic techniques. Femoroacetabular impingement has the potential to cause hip osteoarthritis. The role of hip arthroscopy in the treatment of formally established hip osteoarthritis is limited and has better results in young patients with early degenerative changes.

  15. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  16. Penile Implants

    MedlinePlus

    ... Three-piece inflatable implants use a fluid-filled reservoir implanted under the abdominal wall, a pump and ... an erection, you pump the fluid from the reservoir into the cylinders. Afterward, you release the valve ...

  17. Strain shielding inspired re-design of proximal femoral stems for total hip arthroplasty.

    PubMed

    Cilla, Myriam; Checa, Sara; Duda, Georg N

    2017-02-08

    A large number of hip prosthesis with different designs have been developed. However, the influence of hip implant design changes on the strains induced in the bone remains unclear. The purpose of this study is to better understand the mechanics of short stem total hip arthroplasty. Specifically, it investigates whether strain shielding can be avoided by changing implant shape and/or material properties. It is hypothesized that the re-design of existing implant designs can result in further reduction of strain shielding and thus keep bone loss minimal following total hip replacement. Finite element methods were used to compare healthy and implanted models. The local mechanics strains/stresses in the intact and implanted femurs were determined under patient-specific muscle and joint contact forces. Results suggest that small changes in implant geometry and material properties have no major effect on strain shielding. Furthermore, it was found that improvement depends on a dramatic re-design of the original implant design. Whereas the benefit of this strategy of modification of the original geometry of a given short-stemmed hip consists in reduced bone remodeling, care should be taken with regard to long-term bone anchorage and implant fatigue strength. It is also shown that geometrical and material changes have a limited potential in avoiding strain shielding even in short-stemmed implants. Finally, it is suggested that an understanding of the influence of these changes on the strain distribution within the bone can guide in the process of optimizing the current stem designs toward minimal strain shielding effects. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  18. Design of a biomimetic polymer-composite hip prosthesis.

    PubMed

    Bougherara, Habiba; Bureau, Martin; Campbell, Melissa; Vadean, Aurelian; Yahia, L'Hocine

    2007-07-01

    A new biomimetic composite hip prosthesis (stem) was designed to obtain properties similar to those of the contiguous bone, in particular stiffness, to allow normal loading of the surrounding femoral bone. This normal loading would reduce excessive stress shielding, known to result in bone loss, and micromotions at the bone-implant interface, leading to aseptic prosthetic loosening. The design proposed is based on a hollow substructure made of hydroxyapatite-coated, continuous carbon fiber (CF) reinforced polyamide 12 (PA12) composite with an internal soft polymer-based core. Different composite configurations were studied to match the properties of host tissue. Nonlinear three-dimensional analysis of the hip prosthesis was carried out using a three-dimensional finite element bone model based on the composite femur. The performance of composite-based hip and titanium alloy-based (Ti-6Al-4V) stems embedded into femoral bone was compared. The effect of core stiffness and ply configuration was also analyzed. Results show that stresses in composite stem are lower than those in Ti stem, and that the femoral bone implanted with composite structure sustains more load than the one implanted with Ti stem. Micromotions in the composite stem are significantly smaller than those in Ti stem over the entire bone-implant surface because of the favorable interfacial stress distribution.

  19. Failure analysis of the cement mantle in total hip arthroplasty with an efficient probabilistic method.

    PubMed

    Kaymaz, Irfan; Bayrak, Ozgu; Karsan, Orhan; Celik, Ayhan; Alsaran, Akgun

    2014-04-01

    Accurate prediction of long-term behaviour of cemented hip implants is very important not only for patient comfort but also for elimination of any revision operation due to failure of implants. Therefore, a more realistic computer model was generated and then used for both deterministic and probabilistic analyses of the hip implant in this study. The deterministic failure analysis was carried out for the most common failure states of the cement mantle. On the other hand, most of the design parameters of the cemented hip are inherently uncertain quantities. Therefore, the probabilistic failure analysis was also carried out considering the fatigue failure of the cement mantle since it is the most critical failure state. However, the probabilistic analysis generally requires large amount of time; thus, a response surface method proposed in this study was used to reduce the computation time for the analysis of the cemented hip implant. The results demonstrate that using an efficient probabilistic approach can significantly reduce the computation time for the failure probability of the cement from several hours to minutes. The results also show that even the deterministic failure analyses do not indicate any failure of the cement mantle with high safety factors, the probabilistic analysis predicts the failure probability of the cement mantle as 8%, which must be considered during the evaluation of the success of the cemented hip implants.

  20. CRISPR interference and priming varies with individual spacer sequences.

    PubMed

    Xue, Chaoyou; Seetharam, Arun S; Musharova, Olga; Severinov, Konstantin; Brouns, Stan J J; Severin, Andrew J; Sashital, Dipali G

    2015-12-15

    CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid 'primed' adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR-Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed 'naïve' adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection.

  1. Conservation of sequence in recombination signal sequence spacers.

    PubMed Central

    Ramsden, D A; Baetz, K; Wu, G E

    1994-01-01

    The variable domains of immunoglobulins and T cell receptors are assembled through the somatic, site specific recombination of multiple germline segments (V, D, and J segments) or V(D)J rearrangement. The recombination signal sequence (RSS) is necessary and sufficient for cell type specific targeting of the V(D)J rearrangement machinery to these germline segments. Previously, the RSS has been described as possessing both a conserved heptamer and a conserved nonamer motif. The heptamer and nonamer motifs are separated by a 'spacer' that was not thought to possess significant sequence conservation, however the length of the spacer could be either 12 +/- 1 bp or 23 +/- 1 bp long. In this report we have assembled and analyzed an extensive data base of published RSS. We have derived, through extensive consensus comparison, a more detailed description of the RSS than has previously been reported. Our analysis indicates that RSS spacers possess significant conservation of sequence, and that the conserved sequence in 12 bp spacers is similar to the conserved sequence in the first half of 23 bp spacers. PMID:8208601

  2. Impact of spacer thickness on biofouling in forward osmosis.

    PubMed

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Space Station Long Spacer Element begins processing at KSC

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Long Spacer, a component of the International Space Station, arrives and is moved to its test stand in the northeast corner of the high bay in KSC's Space Station Processing Facility. The Long Spacer provides structural support for the outboard Photovoltaic Modules that supply power to the station. Now just a structure, the Long Spacer will have attached to it as part of processing a heat dissipation radiator and two Pump and Flow Control subassemblies that circulate ammonia to cool the solar array electronics. Also to be mounted are ammonia fluid lines as part of the cooling system and the cabling necessary for power and control of the station. The Long Spacer becomes an integral part of a station truss segment when it is mated with the Integrated Equipment Assembly, which stores the electrical power generated by the solar arrays for use by the station modules. The Long Spacer is being processed in preparation for STS-97, currently planned for launch aboard Discovery in April 1999.

  4. Gas-insulated substation spacer surface degradation analysis

    SciTech Connect

    Chu, F.Y.; Braun, J.M. )

    1990-06-01

    The objective of the project was to develop surface analysis techniques which can correlate the performance of spacers in SF{sub 6} insulated switchgear with changes in their dielectric and chemical characteristics after exposure to SF{sub 6} arcing byproducts and low energy flashovers. Critical material parameters responsible for spacer performance were investigated by optical and scanning electron microscopy, electron spectroscopy for chemical analysis, thermogravimetric analysis and electrical surface resistance measurements. Results related to arc byproduct resistance and tracking resistance of seven types of filled epoxy spacer materials are presented. Degradation mechanisms have been proposed to explain the differing material behaviour. The study shows that the interaction of certain types of filler and resin systems with the SF{sub 6} spark and the decomposed gas is responsible for the degradation in impulse withstand performance. A practical technique using surface electrical resistance to detect degraded spacer after exposure to large quantities of arc byproducts has been developed and the construction of a probe for spacer surface assessment was described. 15 refs., 28 figs., 8 tabs.

  5. CT-based surgical planning software improves the accuracy of total hip replacement preoperative planning.

    PubMed

    Viceconti, M; Lattanzi, R; Antonietti, B; Paderni, S; Olmi, R; Sudanese, A; Toni, A

    2003-06-01

    The present study is aimed to compare accuracy and the repeatability in planning total hip replacements with the conventional templates on radiographs to that attainable on the same clinical cases when using CT-based planning software. The sizes of the cementless components planned with new computer aided preoperative planning system called Hip-Op and with standard templates were compared to those effectively implanted. The study group intentionally included only difficult clinical cases. The most common aetiology was congenital dysplasia of hip (65.6%). The Hip-Op planning system allowed the surgeons to obtain a preoperative planning more accurate than with templates, especially for the socket. Assuming correct a size planned one calliper above or below that implanted the accuracy increased from 83% for the stem and 69% for the socket when using templates to 86% for the stem and 93% for the socket when using the Hip-Op system. The repeatability of the Hip-Op system was found comparable to that of the template procedure, which is much more familiar to the surgeons. Furthermore, the repeatability of the preoperative planning with the Hip-Op system was consistent between surgeons, independently from their major or minor experience. The study clearly shows the advantages of a three-dimensional computer-based preoperative planning over the traditional template planning, especially when deformed anatomies are involved. The surgical planning performed with the Hip-Op system is accurate and repeatable, especially for the socket and for less experienced surgeons.

  6. Lessons learned from study of congenital hip disease in adults

    PubMed Central

    Hartofilakidis, George; Lampropoulou-Adamidou, Kalliopi

    2016-01-01

    Orthopaedic surgeons specialising in adult hip reconstruction surgery often face the problem of osteoarthritis secondary to congenital hip disease (CHD). To achieve better communication among physicians, better treatment planning and evaluation of the results of various treatment options, an agreed terminology is needed to describe the entire pathology. Furthermore, a generally accepted classification of the deformities is necessary. Herein, the authors propose the use of the term “congenital hip disease” and its classification as dysplasia, low dislocation and high dislocation. Knowledge of the CHD natural history facilitates comprehension of the potential development and progression of the disease, which differs among the aforementioned types. This can lead to better understanding of the anatomical abnormalities found in the different CHD types and thus facilitate preoperative planning and choice of the most appropriate management for adult patients. The basic principles for improved results of total hip replacement in patients with CHD, especially those with low and high dislocation, are: Wide exposure, restoration of the normal centre of rotation and the use of special techniques and implants for the reconstruction of the acetabulum and femur. Application of these principles during total hip replacement in young female patients born with severe deformities of the hip joint has led to radical improvement of their quality of life. PMID:28032030

  7. Geriatric hip fracture clinical pathway: the Hong Kong experience.

    PubMed

    Lau, T W; Leung, F; Siu, D; Wong, G; Luk, K D K

    2010-12-01

    Geriatric hip fracture is one of the commonest fractures in orthopaedic trauma. There is a trend of further increase in its incidence in the coming decades. Besides the development of techniques and implants to overcome the difficulties in fixation of osteoporosis bone, the general management of the hip fracture is also very challenging in terms of the preparation of the generally poorer pre-morbid state and complicate social problems associated with this group of patients. In order to cope with the increasing demand, our hospital started a geriatric hip fracture clinical pathway in 2007. The aim of this pathway is to provide better care for this group of patients through multidisciplinary approach. From year 2007 to 2009, we had managed 964 hip fracture patients. After the implementation of the pathway, the pre-operative and the total length of stay in acute hospital were shortened by over 5 days. Other clinical outcomes including surgical site infection, 30 days mortality and also incidence of pressure sore improved when compared to the data before the pathway. The rate of surgical site infection was 0.98%, and the 30 days mortality was 1.67% in 2009. The active participation of physiotherapists, occupational therapists as well as medical social workers also helped to formulate the discharge plan as early as the patient is admitted. In conclusion, a well-planned and executed clinical pathway for hip fracture can improve the clinical outcomes of the geriatric hip fractures.

  8. Preventing Leg Length Discrepancy and Instability After Total Hip Arthroplasty.

    PubMed

    Sculco, Peter K; Austin, Matthew S; Lavernia, Carlos J; Rosenberg, Aaron G; Sierra, Rafael J

    2016-01-01

    Restoration of equal leg lengths and dynamic hip stability are essential elements of a successful total hip arthroplasty. A careful clinical examination, a preoperative plan, and appropriate intraoperative techniques are necessary to achieve these goals. Preoperative identification of patients at risk for residual leg length discrepancy allows surgeons to adjust the surgical approach and/or the type of implant and provide better preoperative patient education. The use of larger femoral heads, high-offset stem options, and enhanced soft-tissue repairs have improved impingement-free range of motion as well as dynamic hip stability and have contributed to an overall reduction in dislocation. Methods for accurate leg length restoration and component positioning include anatomic landmarks, intraoperative radiographs, intraoperative calipers, stability testing, and computer-assisted surgery. If recurrent instability occurs after total hip arthroplasty, the underlying cause for dislocation should be identified and treated; this may include the use of semiconstrained dual-mobility or fully constrained liners, depending on abductor function. Surgeons should be aware of the clinical and surgical techniques for achieving leg length equalization and dynamic hip stability in total hip arthroplasty.

  9. Bearing surfaces in hip replacement – Evolution and likely future

    PubMed Central

    Kumar, Narinder; Arora, Gen N.C.; Datta, Barun

    2014-01-01

    Total hip arthroplasty has evolved from the first total hip arthroplasty in 1938, through the revolutionization of hip arthroplasty by principles of low friction arthroplasty introduced by Sir John Charnley in 1960s to the present state of the art implants and techniques. The main concern regarding failure of total hip arthroplasty has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. Therefore, recent research has been focussing on alternative bearing surfaces to reduce the particulate debris generated. These bearing surfaces include ceramic-polyethylene, metal–metal as well as ceramic–ceramic articulations and have demonstrated lesser friction rates as well as significantly lower wear rates as compared to widely used metal on polyethylene surfaces. Clinical experience until now has shown that metal on metal articulations have significant safety concerns whereas metal-on-highly crosslinked polyethylene, ceramic on ceramic and ceramic on highly crosslinked polyethylene articulations have shown encouraging results to hold promise for wider use in younger and more active patients. This review article discusses positives and drawbacks of various bearing surfaces in current clinical use in total hip arthroplasty as well as briefly explores the newer technologies on the horizon which may even further decrease wear and improve total hip arthroplasty survivorship. PMID:25382913

  10. Epidemiology of hip fractures.

    PubMed

    Kannus, P; Parkkari, J; Sievänen, H; Heinonen, A; Vuori, I; Järvinen, M

    1996-01-01

    There were an estimated 1.66 million hip fractures world-wide in 1990. According to the epidemiologic projections, this worldwide annual number will rise to 6.26 million by the year 2050. This rise will be in great part due to the huge increase in the elderly population of the world. However, the age-specific incidence rates of hip fractures have also increased during the recent decades and in many countries this rise has not leveled off. In the districts where this increase has either showed or leveled off, the change seems to especially concern women's cervical fractures. In men, the increase has continued unabated almost everywhere. Reasons for the age-specific increase are not known: increase in the age-adjusted incidence of falls of the elderly individuals with accompanying deterioration in the age-adjusted bone quality (strength, mineral density) may partially explain the phenomenon. The growth of the elderly population will be more marked in Asia, Latin America, the Middle East, and Africa than in Europe and North America, and it is in the former regions that the greatest increments in hip fracture are projected so that these regions will account for over 70% of the 6.26 million hip fractures in the year 2050. The incidence rates of hip fractures vary considerably from population to population and race to race but increase exponentially with age in every group. Highest incidences have been described in the whites of Northern Europe (Scandinavia) and North America. In Finland, for example, the 1991 incidence of hip fractures was 1.1% for women and 0.7% for men over 70 years of age. Among elderly nursing home residents, the figures can be as high as 6.2% and 4.9%. The lifetime risk of a hip fracture is 16%-18% in white women and 5%-6% in white men. At the age of 80 years, every fifth woman and at the age of 90 years almost every second woman has suffered a hip fracture. Since populations are aging worldwide, the mean age of the hip fracture patients are

  11. Hip Resurfacing: An Alternative to Conventional Hip Replacement?

    MedlinePlus

    ... bone is reshaped and capped with a metal prosthesis. The hip socket is fitted with a metal ... but higher levels may be problematic. The socket prosthesis for a traditional hip replacement is usually lined ...

  12. Cost Analysis of Ceramic Heads in Primary Total Hip Arthroplasty.

    PubMed

    Carnes, Keith J; Odum, Susan M; Troyer, Jennifer L; Fehring, Thomas K

    2016-11-02

    The advent of adverse local tissue reactions seen in metal-on-metal bearings, and the recent recognition of trunnionosis, have led many surgeons to recommend ceramic-on-polyethylene articulations for primary total hip arthroplasty. However, to our knowledge, there has been little research that has considered whether the increased cost of ceramic provides enough benefit over cobalt-chromium to justify its use. The primary purpose of this study was to compare the cost-effectiveness of ceramic-on-polyethylene implants and metal-on-polyethylene implants in patients undergoing total hip arthroplasty. Markov decision modeling was used to determine the ceramic-on-polyethylene implant revision rate necessary to be cost-effective compared with the revision rate of metal-on-polyethylene implants across a range of patient ages and implant costs. A different set of Markov models was used to estimate the national cost burden of choosing ceramic-on-polyethylene implants over metal-on-polyethylene implants for primary total hip arthroplasties. The Premier Research Database was used to identify 20,398 patients who in 2012 were ≥45 years of age and underwent a total hip arthroplasty with either a ceramic-on-polyethylene implant or a metal-on-polyethylene implant. The cost-effectiveness of ceramic heads is highly dependent on the cost differential between ceramic and metal femoral heads and the age of the patient. At a cost differential of $325, ceramic-on-polyethylene bearings are cost-effective for patients <85 years of age. At a cost differential of $600, it is cost-effective to utilize ceramic-on-polyethylene bearings in patients <65 years of age, and, at a differential of $1,003, ceramic-on-polyethylene bearings are not cost-effective at any age. The ability to recoup the initial increased expenditure of ceramic heads through a diminished lifetime revision cost is dependent on the price premium for ceramic and the age of the patient. A wholesale switch to ceramic bearings

  13. SU-E-J-230: Effect of Metal Hip Prosthesis On the Accuracy of Electromagnetic Localization and Tracking

    SciTech Connect

    Butler, W; Merrick, G; Kurko, B; Bittner, N

    2014-06-01

    Purpose: To quantify the effect of metal hip prosthesis on the ability to track and localize electromagnetic transponders. Methods: Three Calypso transponders were implanted into two prostate phantoms. The geometric center of the transponders were identified on computed tomography and set as the isocenter. With the phantom stationary on the treatment table and the tracking array 14-cm above the isocenter, data was acquired by the Calypso system at 10 Hz to establish the uncertainty in measurements. Transponder positional data was acquired with unilateral hip prostheses of different metallic compositions and then with bilateral hips placed at variable separation from the phantom. Results: Regardless of hip prosthesis composition, the average vector displacement in the presence of a unilateral prosthesis was < 0.5 mm. The greatest contribution to overall vector displacement occurred in the lateral dimension. With bilateral hip prosthesis, the average vector displacement was 0.3 mm. The displacement in the lateral dimension was markedly reduced compared with a unilateral hip, suggesting that there was a countervailing effect with bilateral hip prosthesis. The greatest average vector displacement was 0.6 mm and occurred when bilateral hip prostheses were placed within 4 cm of the detector array. Conclusion: Unilateral and bilateral hip prostheses did not have any meaningful effect on the ability to accurately track electromagnetic transponders implanted in a prostate phantom. At clinically realistic distances between the hip and detection array, the average tracking error is negligible.

  14. The Hyperflexible Hip

    PubMed Central

    Weber, Alexander E.; Bedi, Asheesh; Tibor, Lisa M.; Zaltz, Ira; Larson, Christopher M.

    2015-01-01

    Context: Dance, gymnastics, figure skating, and competitive cheerleading require a high degree of hip range of motion. Athletes who participate in these sports use their hips in a mechanically complex manner. Evidence Acquisition: A search of the entire PubMed database (through December 2013) and additional searches of the reference lists of pertinent articles. Study Design: Systematic review. Level of Evidence: Level 3. Results: Whether innate or acquired, dancers and gymnasts have some hypermobility that allows their hips to be placed in potentially impinging or unstable positions required for their given activity. Such extremes of motion can result in both intra-articular and extra-articular impingement as well as compensatory osseous and muscular pathology. In addition, dancers and gymnasts are susceptible to impingement-induced instability. Dancers with innate generalized hyperlaxity are at increased risk of injury because of their activities and may require longer recovery times to return to play. Both nonoperative and operative treatments (arthroscopic and open) have an important role in returning flexibility athletes to their preoperative levels of sport and dance. Conclusion: Because of the extreme hip motion required and the compensatory soft tissue laxity in dancers and gymnasts, these athletes may develop instability, impingement, or combinations of both. This frequently occurs in the setting of subtle pathoanatomy or in patients with normal bony anatomy. With appropriate surgical indications and the correct operative technique, the treating surgeon can anticipate high levels of return to play for the gymnast and dancer with hip pain. PMID:26137181

  15. Complications in Hip Arthroscopy

    PubMed Central

    Nakano, Naoki; Khanduja, Vikas

    2016-01-01

    Summary Background Recent developments in hip arthroscopic techniques and technology have made it possible in many cases to avoid open surgical dislocation for treating a variety of pathology in the hip. Although early reports suggest favourable results’ using hip arthroscopy and it has been shown to be a relatively safe procedure, complications do exist and can sometimes lead to significant morbidity. Methods This is a review article. The aim of this manuscript is to present the most frequent and/or serious complications that could occur at or following hip arthroscopy and some guidelines to avoid these complications. Conclusion Most complications of hip arthroscopy are minor or transient but serious complications can occur as well. A lot of complication e.g. acetabular labral puncture go unreported. Appropriate education and training, precise and meticulous surgical technique with correct instrumentation, the right indication in the right patient and adherence to advice from mentors and experienced colleagues are all essential factors for a successful outcome. Level of evidence: V. PMID:28066747

  16. Lower Eyelid Retraction Repair with Resorbable Polydioxanone Implants

    PubMed Central

    Alsuhaibani, Adel H.; Al-Faky, Yasser H.

    2016-01-01

    PURPOSE: To report a unique technique to repair lower eyelid retraction using resorbable polydioxanone implants. PATIENTS AND METHODS: This was a retrospective, consecutive, nonrandomized interventional case series. Patients with lower eyelid retraction after trauma repaired facial fracture, thyroid eye disease, lower eyelid blepharoplasty, and long-standing facial palsy were treated with middle lamellar spacer using absorbable polydioxanone implant. All patients were recruited from the King Abdulaziz University Hospital, Riyadh, Saudi Arabia. Only patients with minimum follow-up of 12 months were included in the study. RESULTS: Eight patients (4 males and 4 females) underwent lower eyelid retraction repair using absorbable polydioxanone implant. The mean age was 43 years (range, 23–63 years). All patients noted improved ocular surface symptoms. The improvement in eyelid retraction ranged from 1.5 to 4 mm with an average of 2.7 mm postoperatively. The implant was well tolerated with no major complications. CONCLUSIONS: Several options for spacer materials are available. Absorbable polydioxanone implants seem to be an effective middle lamellar spacer that is a good alternative for repairing middle lamella related lower eyelid retraction and lower eyelid support. PMID:27994395

  17. Wheeze in childhood: is the spacer good enough?

    PubMed Central

    Rajkumar, Veena; Rajendra, Barathi; How, Choon How; Ang, Seng Bin

    2014-01-01

    Max was treated with SABA using an MDI and spacer with facemask and responded well to the initial treatment. You explained to the parents that nebulisers are neither required nor recommended in the treatment of wheezing in their child’s situation. You advised the parents on the proper technique of MDI use with spacer and facemask, as well as care of the equipment. You also gave them a clearly written action plan regarding the efficient management of the next episode of wheeze with MDI and spacer. You further explained the side effects of oral bronchodilators and nebulisers, and why you refrained from using them. Max was given a follow-up appointment to assess his progress, and his parents were advised on the situations when they should go to a doctor or the emergency department. PMID:25631964

  18. Wheeze in childhood: is the spacer good enough?

    PubMed

    Rajkumar, Veena; Rajendra, Barathi; How, Choon How; Ang, Seng Bin

    2014-11-01

    Max was treated with SABA using an MDI and spacer with facemask and responded well to the initial treatment. You explained to the parents that nebulisers are neither required nor recommended in the treatment of wheezing in their child's situation. You advised the parents on the proper technique of MDI use with spacer and facemask, as well as care of the equipment. You also gave them a clearly written action plan regarding the efficient management of the next episode of wheeze with MDI and spacer. You further explained the side effects of oral bronchodilators and nebulisers, and why you refrained from using them. Max was given a follow-up appointment to assess his progress, and his parents were advised on the situations when they should go to a doctor or the emergency department.

  19. Dual mobility cups in total hip arthroplasty

    PubMed Central

    De Martino, Ivan; Triantafyllopoulos, Georgios Konstantinos; Sculco, Peter Keyes; Sculco, Thomas Peter

    2014-01-01

    Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in orthopaedics. With the increase in the number of THAs performed in the world in the next decades, reducing or preventing medical and mechanical complications such as post-operative THA instability will be of paramount importance, particularly in an emerging health care environment based on quality control and patient outcome. Dual mobility acetabular component (also known as unconstrained tripolar implant) was introduced in France at the end of the 1970s as an alternative to standard sockets, to reduce the risk of THA dislocation in patients undergoing primary THA in France. Dual mobility cups have recently gained wider attention in the United States as an alternative option in the prevention and treatment of instability in both primary and revision THA and offer the benefit of increased stability without compromising clinical outcomes and implant longevity. In this article, we review the use of dual mobility cup in total hip arthroplasty in terms of its history, biomechanics, outcomes and complications based on more than 20 years of medical literature. PMID:25035820

  20. Hip screw migration testing: first results for hip screws and helical blades utilizing a new oscillating test method.

    PubMed

    Born, Christopher T; Karich, Bernhard; Bauer, Christoph; von Oldenburg, Geert; Augat, Peter

    2011-05-01

    Despite continued improvement in the methods and devices used to treat intertrochanteric fractures, there remains an unacceptable amount of failures. The cut-out rate for hip screws has been recorded up to 8.3%. To evaluate the migration of different implants under physiological loads, a multiplanar biomechanical test method for hip screws was developed, the first to incorporate a simulation of the human gait cycle by an oscillating flexion/extension movement of the test device. The new method was used to compare different hip screw and blade designs with respect to their directional migration resistance. The test method generated failure modes that were consistent with those observed clinically. Under cyclic loading, the hip screws migrated predominantly in a cephalad direction. In contrast, the helical blades exhibited a distinct migration in their axial direction. The Gamma3 hip screw design showed a significantly higher migration resistance compared with other screw and helical blade designs. The results demonstrate the ability of hip screws to significantly reduce axial migration and prevent cut-out under simulated walking loads. Further, the new multiplanar test method creates a physiological environment that can be used to optimize designs for intertrochanteric fracture fixation. Copyright © 2010 Orthopaedic Research Society.

  1. Midterm Outcome of Cementless Total Hip Arthroplasty in Crowe IV-Hartofilakidis Type III Developmental Dysplasia of the Hip.

    PubMed

    Mu, Wenbo; Yang, Desheng; Xu, Boyong; Mamtimin, Askar; Guo, Wentao; Cao, Li

    2016-03-01

    Developmental dysplasia of the hip (DDH) is widespread in developing countries, and treating Crowe IV-Hartofilakidis Type III DDH in adults requires the use of a highly demanding technique. We sought to determine the outcome of cementless total hip arthroplasty using Zweymüller components to treat Crowe IV-Hartofilakidis Type III DDH. Fifty-eight patients (71 hips) with a mean age of 35.8 years at time of index operation were included in our study. The average duration of follow-up was 70.5 months. The acetabular component was placed in the true acetabulum in all cases, and subtrochanteric shortening osteotomy was performed in 61 hips. With any component revision for any reason as the end point, Kaplan-Meier survivorship analysis at 98 months revealed a cumulative survival rate for implanted components of 91.40%. The mean Harris Hip Score improved from 35.6 preoperatively to 82.9 postoperatively. There were 20 cases of intraoperative fracture, 1 case of complete nerve palsy, and 7 cases of transient nerve palsy. Revision surgery was performed in 7 patients because of cup loosening in 1, severe polyethylene wear in 4, cup breakage in 1, and dislocation in 1. Midterm results for cementless total hip arthroplasty in patients with Crowe IV-Hartofilakidis Type III DDH was satisfactory; however, intraoperative fracture and polyethylene wear were major complications. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Interspinous Spacer versus Traditional Decompressive Surgery for Lumbar Spinal Stenosis: A Systematic Review and Meta-Analysis

    PubMed Central

    Wu, Ai-Min; Zhou, Yong; Li, Qing-Long; Wu, Xin-Lei; Jin, Yong-Long; Luo, Peng; Chi, Yong-Long; Wang, Xiang-Yang

    2014-01-01

    Background Dynamic interspinous spacers, such as X-stop, Coflex, DIAM, and Aperius, are widely used for the treatment of lumbar spinal stenosis. However, controversy remains as to whether dynamic interspinous spacer use is superior to traditional decompressive surgery. Methods Medline, Embase, Cochrane Library, and the Cochrane Controlled Trials Register were searched during August 2013. A track search was performed on February 27, 2014. Study was included in this review if it was: (1) a randomized controlled trial (RCT) or non-randomized prospective comparison study, (2) comparing the clinical outcomes for interspinous spacer use versus traditional decompressive surgery, (3) in a minimum of 30 patients, (4) with a follow-up duration of at least 12 months. Results Two RCTs and three non-randomized prospective studies were included, with 204 patients in the interspinous spacer (IS) group and 217 patients in the traditional decompressive surgery (TDS) group. Pooled analysis showed no significant difference between the IS and TDS groups for low back pain (WMD: 1.2; 95% CI: −10.12, 12.53; P = 0.03; I2 = 66%), leg pain (WMD: 7.12; 95% CI: −3.88, 18.12; P = 0.02; I2 = 70%), ODI (WMD: 6.88; 95% CI: −14.92, 28.68; P = 0.03; I2 = 79%), RDQ (WMD: −1.30, 95% CI: −3.07, 0.47; P = 0.00; I2 = 0%), or complications (RR: 1.39; 95% CI: 0.61, 3.14; P = 0.23; I2 = 28%). The TDS group had a significantly lower incidence of reoperation (RR: 3.34; 95% CI: 1.77, 6.31; P = 0.60; I2 = 0%). Conclusion Although patients may obtain some benefits from interspinous spacers implanted through a minimally invasive technique, interspinous spacer use is associated with a higher incidence of reoperation and higher cost. The indications, risks, and benefits of using an interspinous process device should be carefully considered before surgery. PMID:24809680

  3. Patient-Specific Orthopaedic Implants.

    PubMed

    Haglin, Jack M; Eltorai, Adam E M; Gil, Joseph A; Marcaccio, Stephen E; Botero-Hincapie, Juliana; Daniels, Alan H

    2016-11-01

    Patient-specific orthopaedic implants are emerging as a clinically promising treatment option for a growing number of conditions to better match an individual's anatomy. Patient-specific implant (PSI) technology aims to reduce overall procedural costs, minimize surgical time, and maximize patient outcomes by achieving better biomechanical implant fit. With this commercially-available technology, computed tomography or magnetic resonance images can be used in conjunction with specialized computer programs to create preoperative patient-specific surgical plans and to develop custom cutting guides from 3-D reconstructed images of patient anatomy. Surgeons can then place these temporary guides or "jigs" during the procedure, allowing them to better recreate the exact resections of the computer-generated surgical plan. Over the past decade, patient-specific implants have seen increased use in orthopaedics and they have been widely indicated in total knee arthroplasty, total hip arthroplasty, and corrective osteotomies. Patient-specific implants have also been explored for use in total shoulder arthroplasty and spinal surgery. Despite their increasing popularity, significant support for PSI use in orthopaedics has been lacking in the literature and it is currently uncertain whether the theoretical biomechanical advantages of patient-specific orthopaedic implants carry true advantages in surgical outcomes when compared to standard procedures. The purpose of this review was to assess the current status of patient-specific orthopaedic implants, to explore their future direction, and to summarize any comparative published studies that measure definitive surgical characteristics of patient-specific orthopaedic implant use such as patient outcomes, biomechanical implant alignment, surgical cost, patient blood loss, or patient recovery.

  4. Hip impingement: beyond femoroacetabular

    PubMed Central

    Bardakos, Nikolaos V.

    2015-01-01

    In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known ‘impingement’ syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms. PMID:27011843

  5. Hip fractures in children.

    PubMed

    Boardman, Matthew J; Herman, Martin J; Buck, Brian; Pizzutillo, Peter D

    2009-03-01

    Hip fractures account for <1% of all pediatric fractures. Most are caused by high-energy mechan