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PubMed2006

Detection of potentially valuable polymorphisms in four group I intron insertion sites at the 3'-end of the LSU rDNA genes in biocontrol isolates of Metarhizium anisopliae.

BACKGROUND: The entomopathogenic anamorphic fungus Metarhizum anisopliae is currently used as a biocontrol agent (BCA) of insects. In the present work, we analyzed the sequence data obtained from group I introns in the large subunit (LSU) of rDNA genes with a view to determining the genetic diversity present in an autochthonous collection of twenty-six M. anisopliae isolates selected as BCAs. RESULTS: DNA fragments corresponding to the 3'-end of the nuclear LSU rDNA genes of 26 M. anisopliae isolates were amplified by PCR. The amplicon sizes ranged from 0.8 to 3.4-kb. Four intron insertion sites, according to Escherichia coli J01695 numbering, were detected--Ec1921, Ec2066, Ec2449 and Ec2563--after sequencing and analysis of the PCR products. The presence/absence of introns allowed the 26 isolates to be distributed into seven genotypes. Nine of the isolates tested showed no introns, 4 had only one, 3 two, and 10 displayed three introns. The most frequent insertion sites were Ec1921 and Ec2449. Of the 26 isolates, 11 showed insertions at Ec2563 and a 1754-bp sequence was observed in ten of them. The most-parsimonious (MP) tree obtained from parsimony analysis of the introns revealed a main set containing four-groups that corresponded to the four insertion sites. CONCLUSION: Four insertion sites of group I introns in the LSU rDNA genes allowed the establishment of seven genotypes among the twenty-six biocontrol isolates of M. anisopliae. Intron insertions at the Ec2563 site were observed for first time in this species.

3' Untranslated Regions↗
PubMed1998

Systematic mutation screening of the pro-opiomelanocortin gene: identification of several genetic variants including three different insertions, one nonsense and two missense point mutations in probands of different weight extremes.

Pro-opiomelanocortin (POMC) is the precursor of melanocortins (adrenocorticotropin: ACTH, beta-endorphin, beta-lipotropin: beta-LPH, corticotropin like intermediate peptide, alpha-, beta- and gamma-melanocyte-stimulating hormone: alpha-, beta- and gamma-MSH) some of which act in the brain to reduce food intake and are potential mediators of leptin action. Recently, three different mutations in the POMC gene (POMC) were identified in two unrelated children that lead to early-onset extreme obesity, adrenal insufficiency, and red hair pigmentation. In the present study we systematically screened the coding region of POMC in 96 extremely obese children and adolescents, 60 healthy underweight individuals and 46 patients with anorexia nervosa (AN) and identified several variants. a) A 9 and an 18 base pair insertion (9bp and 18bp: AGC AGC GGC and AGC AGC GGC AGC AGC GGC, respectively, between codon 73 and 74; 1,2). These in-frame variants lead to the insertion of three or six amino acids (Ser-Ser-Gly; Ser-Ser-Gly-Ser-Ser-Gly) carboxy-terminal to gamma-MSH. Frequencies of the 9bp insertion allele varied between 3 and 5% among the different study groups (Pearson's chi2 P>0.5). b) Both an out-of-frame 6 bp insertion (within codon 176: GGG CCC) leading to the insertion of two amino acids (Arg-Ala) and a premature stop-codon (G-7316-T: Glu-180-Stop) within the gamma-LPH sequence were maternally inherited in an obese female proband. This proband inherited another missense mutation from her father (Glu-188-Gly). c) A missense mutation (G-7016-A; Asp-80-Asn) was observed in a single patient with AN who also harboured the 9bp insertion on a paternally derived haplotype. d) The allelic co-occurence of two silent mutations (C-6982-T and C-7285-T) was detected in two obese subjects. e) Two further silent mutations (C-3832-T; C-7111-G) were detected in an underweight and an obese subject, respectively. We conclude that the POMC gene harbors several different polymorphisms and mutations, none of which can readily be associated with the phenotypes under study.

Adolescent↗
PubMed2005

A comparison of sevoflurane-propofol versus sevoflurane or propofol for laryngeal mask airway insertion in adults.

In a prospective, randomized study, we investigated the incidence of successful insertion of laryngeal mask airway (LMA) at the first attempt and the incidence of side effects after LMA insertion using the combination of sevoflurane and propofol as compared with either sevoflurane or propofol alone for induction of anesthesia. Eighty-three unpremedicated ASA physical status I-II patients were anesthetized with a single vital capacity breath (VCB) of sevoflurane 8% supplemented with IV propofol 1.5 mg/kg, a single VCB of sevoflurane 8%, or IV propofol 3 mg/kg. The coinduction technique was associated with the most frequent incidence of successful LMA insertion at the first attempt (93.5%) than either sevoflurane alone (46%) or propofol alone (61.5%) (P < 0.001). Propofol-induced induction of anesthesia allowed the fastest insertion of LMA and was associated with the least frequent incidence of postoperative nausea and vomiting. However, this advantage of propofol was offset by a frequent incidence of pain on injection (69%) and the occurrence of movements during insertion of the LMA (50% in the propofol group versus 19% and 26% in the sevoflurane and sevoflurane-propofol groups, respectively; P < 0.05), as well as a more frequent incidence of apnea (84% in the propofol group versus 7% and 16% in the sevoflurane and sevoflurane-propofol groups, respectively; P < 0.001). The report shows that induction of anesthesia with sevoflurane-propofol combined provides a frequent incidence of successful LMA insertion at the first attempt that is associated with an infrequent incidence of apnea.

Adolescent↗
PubMed2005

Ultrasound-guided epidural catheter insertion in children.

UNLABELLED: Epidural catheters (EC) are often used in pediatric patients for intraoperative and postoperative pain relief. The small anatomical structures and catheter insertion under general anesthesia make it more difficult to perform EC and to prevent damage. In this study we investigated the use of ultrasound (US) in detecting neuraxial structures during insertion and placement of EC in children. ASA I-II children scheduled for elective surgery under combined general and epidural anesthesia were studied. Patients received balanced anesthesia using sevoflurane, opioids and rocuronium. Before EC insertion US examination in a lateral position was done to visualize and identify neuraxial structures. Quality of visualization and site and depth of structures were recorded. Using a sterile kit to hold the US probe in position and enable the visualization of the neuraxial structures, an epidural cannula was inserted, using the loss of resistance technique, as the EC passed under US control to the desired level. Of 25 children, 23 were evaluated. Epidural space, ligamentum flavum, and dural structures were clearly identified and the depth to skin level estimated in all patients. Loss of resistance was visualized in all patients with a lumbar epidural approach. Correlation of US measured depth and depth of loss of resistance was 0.88. In eight of 23 patients EC could be visualized during insertion and in 11 others it could be visualized with additional US planes. US is an excellent tool to identify neuraxial structures in both infants and children. The size and the incomplete ossification of the vertebra allow exact visualization and localization of the depth of the epidural space, the loss of resistance, and all relevant neuraxial structures. IMPLICATIONS: Epidural catheters in children are mostly inserted under sedation or general anesthesia. This study showed that the use of ultrasound could help visualize all relevant neuraxial structures and their site and depth from the skin.

Analgesia, Epidural↗
PubMed1978

Genetic aspects of intracellular motility: cortical localization and insertion of trichocysts in Paramecium tetraurelia.

Wild-type and selected mutants of Paramecium tetraurelia were subjected to detailed analysis of the trichocyst phenotype. The characteristics of morphology, saltatory motility, and cortical insertion of trichocysts were found to be genetically distinguishable. In mutants with defective trichocyst saltatory motility, other intracellular motility systems (i.e. mitochondrial saltatory motility, and cyclosis) appeared to be unaffected. Saltatory motility appears to be an essential intermediate step in the functional development of the trichocyst, since it serves to transport the trichocyst from its site of assembly, deep in the cytoplasm, to the cortex, where it is inserted and becomes discharge-competent. If trichocyst saltatory motility is lost, as in the mutants ndA and tam8, then trichocysts are not transported to the cortex and are therefore not inserted. However, the successful transport of a trichocyst to the cortex does not guarantee the proper insertion of that trichocyst, as in the case of the mutant am. Apparently there are independent steps involved specifically with trichocyst insertion. The gross morphology of the trichocyst appears to be independent of its saltatory motility, and to a degree, independent of cortical insertion.

Animals↗
PubMed2003

The influence of stem insertion rate on the porosity of the cement mantle of hip joint replacements.

This study investigates the effect of stem insertion rate on the porosity of the cement mantle. An experimental protocol was developed to simulate the surgical technique of cementing a prosthetic stem into the medullary canal of the femur. Cement mantle specimens were produced for three different stem insertion rates. The presence of porosity in the cement mantle was investigated. Additionally, the mechanical strength of the bone cement was assessed. Increasing the stem insertion rate did not have a significant effect on the porosity distribution within the bulk cement mantle. However, for all stem insertion rates investigated, the porosity concentration increased significantly moving from the cement/pseudofemur interface through to the stem/cement interface. In all cases, the presence of porosity significantly decreased the mechanical behaviour of the bone cement. High porosity concentration at the stem/cement interface seems to be attributed also to the rheology of the cement during implant insertion. Nevertheless, the surgeon cannot influence the formation of porosity by changing the stem insertion rate.

Arthroplasty, Replacement, Hip↗
PubMed2000

New transposable elements identified as insertions in rice transposon Tnr1.

Tnr1 (235 bp long) is a transposable element in rice. Polymerase chain reactions (PCRs) done with a primer(s) that hybridizes to terminal inverted repeat sequences (TIRs) of Tnr1 detected new Tnr1 members with one or two insertions in rice genomes. Six identified insertion sequences (Tnr4, Tnr5, Tnr11, Tnr12, Tnr13 and RIRE9) did not have extensive homology to known transposable elements, rather they had structural features characteristic of transposable elements. Tnr4 (1767 bp long) had imperfect 64-bp TIRs and appeared to generate duplication of a 9-bp sequence at the target site. However, the TIR sequences were not homologous to those of known transposable elements, indicative that Tnr4 is a new transposable element. Tnr5 (209 bp long) had imperfect 46-bp TIRs and appeared to generate duplication of sequence TTA like that of some elements of the Tourist family. Tnr11 (811 bp long) had 73-bp TIRs with significant homology to those of Tnr1 and Stowaway and appeared to generate duplication of sequence TA, indicative that Tnr11 is a transposable element of the Tnr1/Stowaway family. Tnr12 (2426 bp long) carried perfect 9-bp TIRs, which began with 5'-CACTA- -3' from both ends and appeared to generate duplication of a 3-bp target sequence, indicative that Tnr12 is a transposable element of the En/Spm family. Tnr13 (347 bp long) had 31-bp TIRs and appeared to generate duplication of an 8-bp target sequence. Two sequences, one the transposon-like element Crackle, had partial homology in the Tnr13 ends. All five insertions appear to be defective elements derived from autonomous ones encoding the transposase gene. All had characteristic tandem repeat sequences which may be recognized by transposase. The sixth insertion sequence, named RIRE9 (3852 bp long), which begins with 5'-TG- -3' and ends with 5'- -CA-3', appeared to generate duplication of a 5-bp target sequence. These and other structural features indicate that this insertion is a solo LTR (long terminal repeat) of a retrotransposon. The transposable elements described above could be identified as insertions into Tnr1, which do not deleteriously affect the growth of rice cells.

Base Sequence↗
PubMedDate not supplied

Case study approach to peripherally inserted central catheters.

This article looks at the referral of a patient (Mr H) for parenteral nutrition and the subsequent insertion of a peripherally inserted central catheter (PICC) by the nutrition nurse (NN). It explores the issues directly related to the PICC insertion including the route of intravenous access, the ability of the NN to insert the PICC, preparation, communication and consent, and prevention of the mechanical and septic complications of insertion. This case study demonstrates a good technical mastery of PICC insertion in relation to the issues raised. Mr H was satisfied with his care, offering positive feedback at follow-up visits to clinic. Critical analysis of the case study also revealed implications for further development of the role of the NN in ordering the check X-ray and the development of evidence-based standards and guidelines related to this procedure.

Catheterization, Central Venous↗
PubMed2006

[Amplification of Ds flanking sequences from rice genomic DNA of hybrids of Ac x Ds lines and the analysis of Ds insertions].

Ac and Ds insertions among the genomic DNAs of hybrids of Ac x Ds lines were screened by PCR. The genomic DNAs, which were proved to harbour both Ac and Ds, were used as templates in TAIL-PCR to clone the Ds flanking sequences. The cloned specific fragments were sequenced, and the sequenced Ds flanking sequences were used as query sequences to perform on-line sequence comparing analysis against GenBank by employing BLAST program of NCBI. The information about the chromosome location of Ds-inserted genes, or genes immediately downstream of the inserted sites, and their functional innotations were achieved. Based on the analysis from the cloned 93 Ds-flanking sequences, it was found that 21 hybrid plants had Ds insertions in genic regions, whereas the remaining 72 samples's intergenic regions were inserted by Ds element. Moreover, among the 72 regions, 12 were inserted immediately upstream (within 3 kb) of specific genes. Also, the strategies to improve the performance in cloning the Ds flanking sequences and in screening the Ac/Ds lines were emphasized.

Base Sequence↗
PubMed2007

A generalized born implicit-membrane representation compared to experimental insertion free energies.

An implicit-membrane representation based on the generalized Born theory of solvation has been developed. The method was parameterized against the water-to-cyclohexane insertion free energies of hydrophobic side-chain analogs. Subsequently, the membrane was compared with experimental data from translocon inserted polypeptides and validated by comparison with an independent dataset of six membrane-associated peptides and eight integral membrane proteins of known structure and orientation. Comparison of the insertion energy of alpha-helical model peptides with the experimental values from the biological hydrophobicity scale of Hessa et al. gave a correlation of 93% with a mean unsigned error of 0.64 kcal/mol, when charged residues were ignored. The membrane insertion energy was found to be dependent on residue position. This effect is particularly pronounced for charged and polar residues, which strongly prefer interfacial locations. All integral membrane proteins investigated orient and insert correctly into the implicit-membrane model. Remarkably, the membrane model correctly predicts a partially inserted configuration for the monotopic membrane protein cyclooxygenase, matching experimental and theoretical predictions. To test the applicability and usefulness of the implicit-membrane method, molecular simulations of influenza A M2 as well as the glycophorin A dimer were performed. Both systems remain structurally stable and integrated into the membrane.

Computer Simulation↗
PubMed2004

The distribution of transgene insertion sites in barley determined by physical and genetic mapping.

The exact site of transgene insertion into a plant host genome is one feature of the genetic transformation process that cannot, at present, be controlled and is often poorly understood. The site of transgene insertion may have implications for transgene stability and for potential unintended effects of the transgene on plant metabolism. To increase our understanding of transgene insertion sites in barley, a detailed analysis of transgene integration in independently derived transgenic barley lines was carried out. Fluorescence in situ hybridization (FISH) was used to physically map 23 transgene integration sites from 19 independent barley lines. Genetic mapping further confirmed the location of the transgenes in 11 of these lines. Transgene integration sites were present only on five of the seven barley chromosomes. The pattern of transgene integration appeared to be nonrandom and there was evidence of clustering of independent transgene insertion events within the barley genome. In addition, barley genomic regions flanking the transgene insertion site were isolated for seven independent lines. The data from the transgene flanking regions indicated that transgene insertions were preferentially located in gene-rich areas of the genome. These results are discussed in relation to the structure of the barley genome.

Chromosome Mapping↗
PubMed2002

Topical anesthetics for intravenous insertion in children: a randomized equivalency study.

OBJECTIVES: Children view needle sticks as the worst source of pain and fear in the hospital setting. In an effort to minimize the pain of needle sticks, the use of eutectic mixture of lidocaine and prilocaine (EMLA) has become standard practice in many children's hospitals. Unfortunately, EMLA requires at least 60 minutes to be fully effective and reportedly may cause vasoconstriction, leading to difficult vein cannulation. A newly available local anesthetic (ELA-Max) may require less time and cause less vasoconstriction. The purpose of this randomized crossover study was to investigate the anesthetic equivalence of EMLA and ELA-Max. METHODS: Thirty well children (14 girls and 16 boys) who were between the ages of 7 and 13 years volunteered to have EMLA applied to the dorsal aspect of 1 hand for 60 minutes and ELA-Max applied to the other hand for 30 minutes. Right and left hands were randomized to treatment type and order of intravenous (IV) insertion. Clinical Research Center nurses, blind to the anesthetic randomization, attempted to insert a 22-gauge Teflon IV catheter into a vein in each hand. The children rated pain during IV insertion on the Oucher scale, and the nurse rated the difficulty of the insertion. RESULTS: There was no significant difference in pain ratings for hands that were treated with EMLA (mean: 20.5) or with ELA-Max (mean: 24), and there was no difference for the difficulty of vein cannulation. Children's preprocedure state anxiety was positively associated with pain ratings. CONCLUSIONS: ELA-Max, applied for 30 minutes before IV cannulation, has an anesthetic effectiveness similar to EMLA applied for 60 minutes. Some children rated IV insertion pain fairly high for both hands (eg, 60 on a 0- to 100-point scale) despite anesthetic treatment. Preprocedural anxiety may affect the perception and/or rating of pain. There were no differences between hands that were treated with EMLA or with ELA-Max for success of IV insertion.

Adolescent↗
PubMed2003

Comparison between the jugular and subclavian vein as insertion site for central venous catheters: microbiological aspects and risk factors for colonization and infection.

Bacterial counts were made of catheter insertion site and of catheter tips to help determine risk factors associated with catheterization of the jugular and subclavian veins. Among the 116 patients included in this study, 69% had central venous catheters (CVC) in the subclavian vein. Seven or more days catheterization (p=0.001) and > or =3 invasive devices (p=0.01) were infection risk factors associated with catheterization of the jugular vein. More than half of the patients presented high colony counts at the insertion site (> or =200 CFU/20 cm2) and 27% of the catheter tips were contaminated. The risk factors associated with contaminated catheter tips were > or =14 days hospital stay (p=0.02), > or =7 days catheterization (p=0.01) and antibiotic therapy (p=0.04). Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus were the most common microorganisms at the insertion site (78%) and in the catheter tip (94%). Five patients presented sepsis (4.1%), four caused by Staphylococci and one by GNB. Twelve patients had the same microorganisms at the insertion site and catheter tip. We found a high prevalence of ORSA (62.5%) and ORCoNS (57.1%) in catheter tips. The high counts of staphylococci, including ORSA and ORCoNS, at the insertion site, and the significant association of this colonization with catheter tip contamination, indicate that the skin is an important reservoir of microorganisms associated with catheter-related bloodstream infection (CR-BSI). Health professionals should be aware of this potential source of infection at the CVC insertion site.

Bacteremia↗
PubMed1995

Patterns of osteolysis around total hip components inserted with and without cement.

We reviewed the radiographs of 137 patients (137 hips) who had been managed with a total hip arthroplasty, with insertion of an extensively porous-coated femoral component without cement, because of osteoarthrosis or avascular necrosis. A porous-coated acetabular component had been inserted with cement in sixty-three of these patients (Group A) and without cement in seventy-four patients (Group B). The radiographs were examined for osteolysis, either directly adjacent to the joint or at locations remote from the joint. The mean duration of follow-up was 105 months (range, fifty-four to 142 months). The rate of osteolysis of the acetabulum in the unrevised hips in which the acetabular component had been inserted with cement was 37 per cent (nineteen of fifty-one). The osteolysis was most frequently of the linear type, a pattern that was associated with a high prevalence of loosening in the hips that had a cemented cup (30 per cent [nineteen of sixty-three]). The rate of acetabular osteolysis (18 per cent [thirteen of seventy-one]) in the patients who had a cup that had not been inserted with cement and that had not been revised was not as high as that associated with the surviving cups that had been inserted with cement (p < 0.05). The osteolysis associated with the cups that had not been inserted with cement was localized and expansile, and it was not associated with loosening of the component. However, it produced more loss of bone than did the linear pattern of osteolysis around the cemented cups.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1996

Failure of a non-porous-coated acetabular component inserted without cement in primary total hip arthroplasty.

Thirty-four patients (thirty-eight hips) had a primary total hip arthroplasty with insertion of a non-porous-coated titanium-alloy acetabular component without cement. This component is initially stabilized with use of a central acetabular polyethylene peg, which is inserted into the pelvis, as well as supplementary cortical-bone screws inserted into the ilium. The original diagnosis was degenerative joint disease in thirty-four hips and avascular necrosis in four hips. Twenty-five femoral components were inserted with cement, and thirteen non-porous-coated femoral implants were inserted without cement. The acetabulum was prepared with so-called line-to-line reaming. Thirty-five hips in thirty-one patients were available for clinical and radiographic follow-up at a mean of 4.5 years (range, two to seven years). Serial measurements of the position of the acetabular component revealed that eighteen cups (51 per cent) had migrated. Of these, eleven had been revised. Radiolucent lines of at least one millimeter in thickness at the bone-prosthesis interface were noted adjacent to all but six of the acetabular components. Although this series was small, it demonstrates an unacceptably high rate of failure of non-porous-coated acetabular components after a relatively short duration. We question the efficacy of this acetabular component, inserted without cement, as part of a primary total hip arthroplasty.

Acetabulum↗
PubMed1997

Measurement of polyethylene wear in acetabular components inserted with and without cement. A randomized trial.

We measured the three-dimensional wear of polyethylene after total hip arthroplasty with a titanium metal-backed Mallory-Head prosthesis that was inserted with cement in sixty-nine patients (sixty-nine hips) and with a press-fit titanium metal-backed Mallory-Head prosthesis that was inserted without cement in seventy patients (seventy hips). A modular titanium femoral head was used in all of the hips. The patients in the present study were part of a larger double-blind randomized trial comparing the result of total hip arthroplasty performed with cement with that of the same procedure performed without cement in 250 patients. The criterion for inclusion in the study of polyethylene wear was a minimum duration of follow-up of four years, which was met by 148 patients. As adequate radiographs for digitization were not available for nine patients, 139 patients were included in the present study. The age of the patient, the postoperative Harris hip score, the diameter of the femoral head, the thickness of the liner in the polar region of the acetabular component, and the duration of follow-up were similar for the two groups. The mean rate of volumetric wear of the polyethylene was significantly greater in the prostheses that had been inserted without cement than in those that had been inserted with cement (155.1 cubic millimeters per year compared with 98.5 cubic millimeters per year; p = 0.000008). Thirty-four (49 per cent) of the seventy hips in which the prosthesis had been inserted without cement had evidence of osteolysis on radiographs, compared with twelve (17 per cent) of the sixty-nine hips in the other group (p = 0.0002). Osteolysis was associated with an increased rate of polyethylene wear only in the hips in which the prosthesis had been inserted without cement.

Acetabulum↗
PubMed1999

Resurfacing of the glenoid in total shoulder arthroplasty. A comparison, at a mean of five years, of prostheses inserted with and without cement.

BACKGROUND: Clinically evident loosening of a glenoid component inserted with cement in total shoulder arthroplasty is infrequent, but radiographic changes that indicate loosening at the implant-bone interface are common and have been associated with functional limitation. We compared the results of total shoulder arthroplasties in which the glenoid implant had been inserted with cement with those of arthroplasties in which a bone-ingrowth glenoid implant had been inserted without cement. METHODS: The results of eighty-six consecutive total shoulder arthroplasties, performed by the same surgeon, were retrospectively reviewed between four and seven years after the operation. Fifty-eight shoulders in which the primary glenoid implant was in situ were assessed with use of the Simple Shoulder Test and Short Form-36 questionnaires, clinical examination, and fluoroscopic imaging of the glenoid implant-bone interface. Thirty-two of the glenoid components had been fixed with cement and twenty-six, without cement. RESULTS: Complications occurred in 16 percent (fourteen) of the eighty-six shoulders, and 9 percent (eight) of the shoulders needed a revision operation. None of the revisions were done because of loosening of the glenoid component. Five of the eight revisions involved implants that had been inserted without cement. Three of these implants were revised because of early instability and two, because the polyethylene component had separated from the metal tray of the glenoid implant. With the numbers available, we could not detect any significant differences between the groups with respect to pain, range of motion, function of the shoulder, or general health. Radiographic analysis demonstrated a high level of interobserver agreement (kappa = 0.89). Radiolucent lines were observed after 41 percent (thirteen) of the thirty-two arthroplasties performed with cement compared with 23 percent (six) of the twenty-six arthroplasties performed without cement. The proportion of implants classified as probably loose was approximately three times greater in the group in which cement had been used. Eccentric wear of the posterior rim of the metal tray and focal osteolysis under the metal tray were observed in the group in which the component had been inserted without cement; these findings may indicate a potential for progression of radiographic loosening with increased durations of follow-up. CONCLUSIONS: We concluded that, despite the higher rate of early complications, the intermediate-term outcomes of arthroplasties in which the glenoid implant is inserted without cement are comparable with those of arthroplasties with cementing of the glenoid component.

Adult↗
PubMed2004

Factors affecting the severity of backside wear of modular tibial inserts.

BACKGROUND: The use of modular tibial components in total knee arthroplasty introduces a possible source of polyethylene wear at the nonarticulating (backside) surface. However, it is not known whether this phenomenon is an incidental finding observed in unique specimens or is a feature common to all modular components. The purpose of this study was to determine the type and severity of backside wear in retrieved tibial inserts of several common total knee designs. METHODS: One hundred and twenty-four polyethylene tibial inserts of twelve different designs were retrieved at revision total knee replacements after implantation periods ranging from zero to 180 months. Each insert was visually inspected with use of a stereomicroscope for seven different modes of surface damage in four quadrants defining the backside surface. RESULTS: Pitting, burnishing, and measurable polyethylene protrusions were observed on the backside of polyethylene inserts of implant designs with a variety of different capture mechanisms. Across all implant designs, pitting was observed in 90% of the retrieved specimens; burnishing, in 77%; and protrusion, in 61%. Overall, implants of the IB-II (Insall-Burstein-II) design (Zimmer) exhibited the most severe burnishing, whereas those of the Duracon design (Howmedica) had the most severe pitting. Severe protrusions were noted with inserts of one design (AMK [Anatomic Modular Knee]; DePuy). A longer time in situ was associated with larger polyethylene protrusions, but the severity of pitting and burnishing did not increase with increasing duration of implantation. CONCLUSIONS: Moderate-to-severe wear of the nonarticulating surface of the tibial insert was frequently observed in all designs of knee prostheses, independent of the capture mechanism. These results indicate that new designs of modular tibial components are needed to prevent the generation of polyethylene wear debris through backside wear of total knee replacements.

Humans↗