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PubMed1998

Polyethylene wear from femoral bipolar neck-cup impingement as a cause of femoral prosthetic loosening.

A 33-year-old woman underwent an uncemented bipolar hip arthroplasty for osteoarthrosis of the left hip in 1985. Because of painful aseptic loosening, the bipolar implant was revised to a total hip prosthesis in 1994. Membranous tissues around the implant histologically presented foreign-body reaction against polyethylene debris. The retrieved implant showed polyethylene wear of the rim of the bipolar cup. Three-dimensional measurement of the surface configuration of the polyethylene of the cup indicated that wear debris had been generated almost exclusively from femoral bipolar neck-cup impingement. Volumetric wear in the articulating dome portion of the polyethylene was negligible. This report clearly illustrates how impingement of a bipolar cup on the femoral neck can be a major source of polyethylene wear debris which induces femoral osteolysis and subsequent stem loosening.

Adult↗

PubMed2004

Randomized cross-over trial of polyethylene glycol electrolyte solution and water for colostomy irrigation.

PURPOSE: Water for colostomy irrigation is largely absorbed by the colon, which may result in less efficient expulsion of stool. This study compared the outcome of colonic cleansing with water and polyethylene glycol solution. METHODS: In a cross-over study, 41 colostomy irrigators were randomly assigned to water or polyethylene glycol solution irrigation first and then the other regimen, each for one week. Patients recorded fluid inflow time, total washout time, cramps, leakage episodes, number of stoma pouches used, and satisfaction scores (Visual Analog Scale, 1-10: 1 = poor, and 10 = excellent). The median and interquartile range for each variable was calculated, and the two treatments were compared (Wilcoxon's test). RESULTS: Eight patients failed to complete the study. Thirty-three patients (20 females; mean age, 55 (range, 39-73) years) provided 352 irrigation sessions: water (n = 176), and polyethylene glycol solution (n = 176). Irrigation was performed every 24, 48, and 72 hours by 17, 9, and 7 patients respectively, using 500 ml (n = 1), 750 ml (n = 2), 1,000 ml (n = 16), 1,500 ml (n = 11), 2,000 ml (n = 2), and 3,500 ml (n = 1) of fluid. The median and interquartile range for water vs. polyethylene glycol solution were: fluid inflow time (6 (range, 4.4-10.8) vs. 6.3 (range, 4.1-11) minutes; P = 0.48), total washout time (53 (range, 33-69) vs. 38 (range, 28-55) minutes; P = 0.01), leakage episodes (2.3 (range, 1.7-3.8) vs. 0.7 (range, 0.2-1); P < 0.001), satisfaction score (5.8 (range, 4-7.5) vs. 8.8 (range, 8.3-10); P < 0.001), and stoma pouch usage per week (75 (range, 45-80) vs. 43 (range, 0-80); P = 0.008). No difference was demonstrated for frequency of cramps ( P = 0.24). CONCLUSIONS: Polyethylene glycol solution performed significantly better than water and may be a superior alternative fluid regimen for colostomy irrigation.

Adult↗

PubMed1985

Effects of polyethylene glycol and dextrans on immunoprecipitations: a two-cross immunodiffusion study.

Precipitating titers and immunochemical titers obtained in a wide range of antigen-to-antibody concentration ratios by the two-cross immunodiffusion technique are compared with the corresponding laser light scatter precipitin curves. The two-cross immunodiffusion technique has also been applied to investigate whether polyethylene glycol of molecular mass 6000 and dextrans of molecular masses from 10,000 to 2,000,000 enhance the immunoprecipitation processes of the system human serum IgG-rabbit immune serum at pH 5.5 and 8.1 at 20 degrees C. It was found that the significant increase of precipitating titers of both precipitating components in the presence of polyethylene glycol is a consequence of a strong decrease of solubility of the primary antigen-antibody complex. The decrease of solubility does not affect the immunochemical titer of the immune serum, indicating stoichiometrical invariance of the precipitate at the equivalence. The apparent strong decrease of diffusion coefficients of both antigen and antibody in 20- and 40-g/liter polyethylene glycol solution is attributed to increase of viscosity of the solutions and to a partial self-association of protein molecules due to steric exclusion. In 40-g/liter polyethylene glycol solutions at pH 5.5 every fourth molecular entity of antigen and every third molecular entity of antibody are present in the form of a two-molecular self-associate, whereas in 20-g/liter polyethylene glycol solutions only 1% of antigen molecules and 8% of antibody molecules are associated. With the increase of pH to 8.1 the self-association of protein molecules is strongly further enhanced. Dextrans in 20-g/liter solutions, without regard to their relative molecular masses, do not influence precipitating titers and solubility of the antigen-antibody system at equivalence and do not enhance self-association of protein molecules. The strong decrease of diffusion coefficients of immunoglobulin G antigen and antibodies in dextran solutions is solely attributed to the increase of viscosity of the dextran solutions; hence there was no evidence of interaction of dextrans with serum IgG proteins.

Animals↗

PubMed1979

Release of membrane constituents following polyethylene glycol treatment of HEp-2 cells.

HEp-2 cell monolayers were treated with 40% polyethylene glycol for 5 min which resulted in fusion during the subsequent incubation period. A loss of cell membrane components was detected in the polyethylene glycol-treated as well as phosphate buffer/saline-treated control cells, however the polyethylene glycol-treated cells released nearly twice the amount of [14C]acetate-labeled material and [3H]glycerol-labeled lipids into culture fluids than the control cells. It was further detected that the polyethylene glycol-treated cells released only approximately half the amount of protein, glycoprotein, and glycolipid as the control cells. These results suggest that polyethylene glycol exerts a differential mode of action against cell surface components and causes the treated cells to release membrane components rich in lipids but relatively low in protein and carbohydrate-containing components.

Animals↗

PubMed1977

Functional properties of normal and sickle cell hemoglobins in polyethylene glycol 6000.

The functional properties of human hemoglobin A and S were studied in concentrated solutions of polyethylene glycol. Polyethylene glycol solutions are frequently used as media for protein crystallization. In particular, sickle cell hemoglobin, which does not make X-ray quality crystals in high salt solutions, will form high-quality crystals in polyethylene glycol. Comparison of the functional properties of normal and sickle cell hemoglobin in polyethylene glycol show that pH, anion effects and cooperativity of ligand binding are largely unaffected by polyethylene glycol. This suggests that the crystals grown in this medium are representative of the native structure.

Diphosphoglyceric Acids↗

PubMed1985

Fluid-sorption phenomena in sterilized polyethylene acetabular prostheses.

The weight changes due to fluid-sorption were measured in 62 radiation-sterilized acetabular sockets and 10 unsterilized discs. The materials included two types of ultra-high molecular weight (UHMW) polyethylene (RCH 1000; Hi-Fax 1900) and a carbon-fibre-reinforced polyethylene (CFPE). The fluid absorption curve was consistently biphasic. In the first 30 d soak-period (Phase 1), the initial rate of fluid absorption averaged 153 micrograms/d for conventional UHMW polyethylene and 278 micrograms/d for carbon-fibre-reinforced polyethylene. In Phase 2, beyond 30 d and up to 400 d, fluid absorption reduced to linear rates of 27 micrograms/d for UHMW polyethylene and 43 micrograms/d for CFPE. The latter soak-weight-gain values corresponded to only 0.00016%/d and 0.00034%/d respectively. There was little difference in absorption rates between sterilized and unsterilized samples. However soak rates were generally higher in water compared to serum.

Absorption↗

PubMed1983

Replacement of sodium chloride with dextran or polyethylene glycol for immunoprecipitation of lipopolysaccharide with antibodies in chicken or turkey sera.

Dextran or polyethylene glycol could replace sodium chloride in agarose gels for inducing immunoprecipitation of Pasteurella multocida lipopolysaccharides with antibodies in chicken or turkey sera. Resolution of immunoprecipitates was best when 3% concentrations of either dextran or polyethylene glycol were used. Higher concentrations increased opacity of the gels. Nonspecific precipitation of serum or gamma-globulin fractions in gels was caused by the electrophoresis buffer, dextran, and polyethylene glycol. Dialysis of serum or gamma-globulin fractions against the electrophoresis buffer and soaking gels in buffers of pH greater than 7.0 that contained 3% polyethylene glycol reduced nonspecific precipitation. Incorporation of dextran or polyethylene glycol into gels enhanced immunoprecipitation in rocket immunoelectrophoresis but resulted in slower mobility of antigen.

Animals↗

PubMed2004

Porous polyethylene orbital implant in the pediatric population.

PURPOSE: To determine the incidence of complications of primary insertion of porous polyethylene orbital implant in the pediatric population. DESIGN: Interventional case series. METHODS: Prospective nonrandomized case series of 36 eyes of 36 patients under age 15 years who underwent primary placement of an anteriorly wrapped spherical porous polyethylene orbital implant from March 1998 to August 2002, with at least 17 months of follow-up. RESULTS: The mean age at the time of surgery was 4.6 years. The histopathologic diagnoses after enucleation included intraocular tumor in 22 patients, phthisis bulbi in eight patients, microphthalmos in three patients, Coats disease in two patients, and ruptured traumatic globe in one patient. Twelve patients (33%) had prior ocular surgery. At the time of enucleation, all patients underwent primary placement of spherical porous polyethylene orbital implant anteriorly wrapped with homologous sclera in 30 patients (83%) and autologous sclera in six patients (17%). The spherical implant size was 16 mm in one patient (3%), 18 mm in 10 patients ( 28%), and 20 mm in 25 patients (69%). The prosthesis was fitted after a mean interval of 5 weeks. After a mean follow-up of 44 months (range, 17 to 68 months), there was one case of pyogenic granuloma (3%) and one case of implant exposure (3%). There were no cases of implant extrusion, superior sulcus syndrome, orbital cellulitis, or significant inflammatory response. No porous polyethylene orbital implant was drilled for peg placement. CONCLUSIONS: Anteriorly wrapped primary porous polyethylene orbital implant in the pediatric population appears to be well tolerated with few complications.

Adolescent↗

PubMed2004

Isolated acetabular polyethylene exchange through the anterolateral approach.

Isolated exchange of an acetabular liner, in the presence of a well-fixed acetabular component, has become an established method for the management of polyethylene wear. Various experienced adult-reconstruction surgeons have noted a high incidence of instability following isolated liner exchange. We report the results of isolated liner exchange in 35 patients with polyethylene wear and osteolysis (16 patients) or polyethylene wear and instability (19 patients) with a minimum follow-up of 2 years. Isolated liner exchange was performed through an anterolateral approach in all cases. Postoperative dislocation occurred in 2 of the 35 patients (6%), both with polyethylene wear and osteolysis. Isolated liner exchange was successful in addressing instability in all 19 patients who presented with polyethylene wear and dislocation. Isolated acetabular liner exchange performed through an anterolateral approach carries an acceptable dislocation rate.

Acetabulum↗

PubMed2007

Catastrophic failure of a modular revision total hip polyethylene insert.

Early catastrophic failure of a modular polyethylene component is a potential problem after revision total hip arthroplasty. We describe an unusual case of polyethylene failure that occurred within 18 months of implantation in which no obvious technical error or mechanical failure was identified. The acetabular polyethylene insert was prepared with gas plasma sterilization, and the shelf life was 4 months. Radiographic evaluation used generalized Hough transforms to assess the cup articulation. We identified cup penetration of 2.8 mm before revision and catastrophic destruction of the polyethylene liner at the time of revision. Possible factors implicated for failure included a thin polyethylene liner, increased hip separation, femoral head mismatch, and the high activity level of a younger patient. We believe that this case report highlights the need for future investigations of these subtle factors.

Arthroplasty, Replacement, Hip↗

PubMed2004

The influence of molecular weight, crosslinking and counterface roughness on TNF-alpha production by macrophages in response to ultra high molecular weight polyethylene particles.

The response of murine macrophages to clinically relevant polyethylene wear particles generated from different polyethylenes at various time points and volumetric doses in vitro was evaluated. Clinically relevant ultra high molecular weight polyethylene (UHMWPE) wear debris was generated in vitro in a lubricant of RPMI 1640 supplemented with 25% (v/v) foetal calf serum using a multi-directional pin-on-plate wear rig under sterile conditions. Wear debris was cultured with C3H murine peritoneal macrophages at various particle volume (microm(3)): cell number ratios. The secretion of TNF-alpha was determined by ELISA. Initially the effect of molecular weight of UHMWPE was considered. Higher molecular weight GUR415HP was shown to have a lower wear rate than the lower molecular weight GUR1120, however a greater volume of the wear debris produced by the high molecular weight GUR415HP was in the 0.1-1.0 microm size range. Wear debris from GUR415HP produced significant levels of TNF-alpha at a concentration of 1 microm(3)/cell while at least 10 microm(3)/cell of GUR1120 wear debris per cell was needed to produce significant levels of TNF-alpha. Secondly the effects of crosslinking GUR1050 was examined when worn against a scratched counterface. The wear rate of the material was shown to decrease as the level of crosslinking increased. However the materials crosslinked with 5 and 10 Mrad of gamma irradiation produced higher percentages of 0.1-1.0 microm size wear particles than the non-crosslinked material. While the crosslinked material was able to stimulate cells to produce significantly elevated TNF-alpha levels at a particle concentration of just 0.1 microm(3)/cell only concentrations of 10 microm(3)/cell and above of the non-crosslinked wear debris were stimulatory. When the counterface was changed from scratched to smooth the wear rate for all three GUR1050 materials was further reduced. For the first time nanometre size wear particles were observed from polyethylene which reduced the percentage mass of debris in the 0.1-1.0 microm size range. For all three materials on the smooth counterface only concentrations of 50 microm(3)/cell and above were stimulatory. This study has demonstrated that molecular weight, crosslinking and counterface roughness are important factors in determining the biological activity of polyethylene.

Animals↗

PubMed2005

Small doses of the unabsorbable substance polyethylene glycol 3350 accelerate oro-caecal transit, but slow gastric emptying in healthy subjects.

BACKGROUND: Polyethylene glycol 3350 increases stool frequency and accelerates colonic transit. Used as a laxative, it proved effective in patients with normal and slow transit. Although free of severe side effects, it may cause nausea and vomiting. The effect of this substance on upper gut transit has not been studied. AIM: To investigate the effect of polyethylene glycol 3350 on gastric emptying and oro-caecal transit in 12 healthy subjects. METHODS: In a randomised controlled study, isosmotic polyethylene glycol 3350 electrolyte balanced solution, in the maximal recommended dose or isosmotic electrolyte solution, was administered after breakfast and lunch on separate days. Gastric half-emptying time and oro-caecal transit time were measured using [13C]-octanoate and lactose-[13C] ureide breath tests. RESULTS: Isosmotic polyethylene glycol 3350 electrolyte solution, as compared to isosmotic electrolyte solution, decreased oro-caecal transit time from 424+/-28 to 314+/-17 min (P = 0.001). Gastric half-emptying time was significantly increased (84+/-6 min versus 127+/-14 min; P = 0.006). CONCLUSION: Polyethylene glycol 3350 accelerate oro-caecal transit in healthy subjects, but also cause an important delay in gastric emptying. The delay in gastric emptying may be of clinical significance in patients who have associated gastroparesis.

Adult↗

PubMed2006

Wear-induced osteolysis and synovial swelling in a patient with a metal-polyethylene wrist prosthesis.

We present a patient with a metal and polyethylene wrist prosthesis who had recurrent synovial swelling on the volar side of the wrist. Surgical exploration showed synovitis, a severely worn and broken polyethylene insert, polyethylene wear particles, and titanium debris from fretting corrosion. Pathological analysis showed macrophage-phagocytosing polyethylene wear particles and titanium oxide debris. This shows that polyethylene and titanium wear in wrist prosthesis might be a bigger problem than originally believed.

Adult↗

PubMed2004

The effectiveness of polyethylene versus titanium particles in inducing osteolysis in vivo.

Bearing surface wear and periprosthetic osteolysis due to wear particles are among the most common reasons for joint replacement failure. A murine calvarial model of wear particle-induced osteolysis has been used to identify different biologic factors associated with this problem and to test nonsurgical methods of modulating the host response to particulate debris. This model has utilized titanium particles, however, in clinical practice the most common source of particulate debris is polyethylene particles from bearing surface wear. We now report a calvarial model of wear particle-induced osteolysis based on commercially available polyethylene particles. We found that compared to sham surgery osteoclast recruitment and bone resorption can be induced by introduction of the titanium particles or polyethylene particles. However, bone resorption was significantly higher with polyethylene particles compared to titanium particles (p=0.02). We consider the polyethylene based murine calvarial model of wear particle-induced osteolysis a reliable and clinically relevant tool to understand the host factors and potential pharmacologic interventions that can influence wear debris generated osteolysis. This model might serve as an extension of the well-established titanium based bone resorption model.

Animals↗

PubMedDate not supplied

Analysis of a retrieved polyethylene total disc replacement component.

BACKGROUND CONTEXT: Although total disc replacements have been performed in Europe since the 1980s, this type of surgery is still new in the United States. The clinical performance of polyethylene in total disc replacements is still not well understood. PURPOSE: To describe the wear, surface damage, oxidation and mechanical properties in an explanted polyethylene total disc replacement component. STUDY DESIGN/SETTING: Case report, analysis of retrieved implant. PATIENT SAMPLE: Case report. OUTCOME MEASURES: Analysis of wear, oxidation and mechanical properties in the retrieved total disc replacement. METHODS: A 49-year-old female patient was implanted at L5-S1 with an SB Charite total disc prosthesis (DePuy Spine, Raynham, MA). After 1.6 years, the patient underwent a posterior, instrumented fusion because of intractable low back, left buttock and radicular left leg pain. Preoperative diagnostics revealed loosening at the bone implant interface at L5 and S1, anterior migration of the L5 base plate and severe degeneration of the L5-S1 facet joints. The retrieved polyethylene core showed evidence of damage around the periphery or rim. Transverse, subsurface cracks in the polyethylene, which initiated near the rim and penetrated into the interior of the component, were imaged using thin-film optical microscopy and micro-computed-tomography imaging. Analysis using Fourier transform infrared spectroscopy (American Society for Testing and Materials [ASTM] F2102) documented low levels of oxidation within 1 mm of the articulating surface. Miniature specimen mechanical testing (ASTM F2183), conducted near the surface where the oxidation was greatest, demonstrated that the mechanical properties were not substantially degraded. CONCLUSION: In this case, the anterior revision surgery was difficult and potentially life-threatening. The revision strategy of an instrumented posterior fusion to salvage a failed SB Charite disc replacement may be unpredictable and, in this case, ultimately unsuccessful. Despite the small size of the retrieved polyethylene core, ASTM standard test techniques developed for analysis of retrieved hip and knee replacements were readily adapted for the total disc prosthesis.

Arthroplasty, Replacement↗

PubMedDate not supplied

Prospective, randomized trial comparing sodium phosphate solution with polyethylene glycol-electrolyte lavage for colonoscopy preparation.

We performed a prospective randomized trial in a predominantly outpatient colonoscopy population to see how preparation with oral sodium phosphate solution compares with polyethylene glycol-electrolyte lavage in terms of the quality of colon cleansing, ease of preparation, and gastrointestinal intolerance. Before colonoscopy, a nurse administered a questionnaire to the patient to assess how well the preparation was tolerated (scale from 1 to 5:1 = easy, to 5 = unable to finish) and about the presence of four symptoms: abdominal pain, nausea, vomiting, and dizziness. The quality of colon cleansing was graded by the attending gastroenterologist, who was unaware of how the patient was prepared or tolerated the preparation (1 = excellent, 2 = good, 3 = fair, 4 = poor). The overall quality of bowel preparation with polyethylene glycol lavage was slightly better than with sodium phosphate (mean score, 1.93 vs 2.07); however, the difference was not statistically different. No statistical difference was seen in the frequency of patients with poor preparations (14.2% for sodium phosphate, 9.6% for polyethylene glycol lavage). Patients found preparation with sodium phosphate to be somewhat easier than polyethylene glycol lavage (mean score, 2.07 vs 2.41; p = 0.05). No difference was seen in the incidence of abdominal pain, nausea, or vomiting. Dizziness was more common with sodium phosphate but was mild and not believed to be clinically important. We conclude that the quality of colon cleansing is similar with polyethylene glycol lavage and oral sodium phosphate solution, with satisfactory preparation seen in 85% to 90% of patients. Patients found preparation with sodium phosphate to be slightly easier to tolerate.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed2003

Adsorption of polyethylene standards from decalin on liquid chromatography column packings.

Linear polyethylene and isotactic polypropylene standards were injected into columns which contained MFI (SH-300 and silicalite) or faujasite (CBV-780) type zeolites. 1,2,4-Trichlorobenzene, cyclohexanone, 2-ethyl-hexanol, decalin and tetralin were used as mobile phases at 140 degrees C. It was found that polyethylene is fully retained on zeolite SH-300 when decalin is used as a mobile phase. Moreover, polyethylene is partially retained on zeolite SH-300 from tetralin and from 1,2,4-tichlorobenzene, on silicalite from decalin and in a very small extent on zeolite CBV-780 from decalin. Using all other solvents, polyethylene and polypropylene were not retained in any of the columns tested. This is the first experimental observation of polyethylene adsorption from a solvent on a chromatographic stationary phase.

Adsorption↗

PubMed2005

[Dual articulation retentive acetabular liners and wear: surface analysis of 40 retrieved polyethylene implants].

PURPOSE OF THE STUDY: The original concept of dual articulation retentive liners has been implemented in routine clinical practice for total hip arthroplasty since 1976. The retentive liner improves stability and the dual mobility favors preservation of joint motion. In this study, we analyzed wear of the two concave and convex surfaces in 40 retrieved polyethylene implants in order to search for factors favoring wear. MATERIAL AND METHODS: Forty polyethylene inserts were examined. These implants had been removed after mean implantation of eight years. Mean patient age at implantation was 48 years. The inserts were removed because of prosthesis infection or mechanical failure. Macroscopic examination was followed by a surface analysis with direct measurement of alterations of the curvature radii. Internal concavity was measured in the three dimensions using a 4-mm stylus (BNH 706). External convexity was measured by lateral projection. The estimated error was +/- 5 microm for both measurement methods. Manufacturers' tolerances for these implants were approximately 50 microm. Linear and volumetric wear was determined by comparing the measured dimensions with the theoretical dimensions of new inserts. RESULTS: Macroscopically, all of the pieces studied had lost their initial striation on the convex surface; 40% of the pieces displayed visible wear of the retentive collar. Mean annual wear was 9 microm (SD 9microm) for the convex surface and 73 microm (SD 69 microm) for the concave surface. Mean total wear, taken as the sum of the wears on the convex and concave surfaces was 82 microm (SD 72 microm). Volumetric wear was 28.9 mm3/yr for the convex surface (SD 27.6) and 25.5 for the concave surface (SD 23.2) giving a mean annual total volumetric wear of 54.3 mm3/yr (SD 39.6). DISCUSSION: Total wear observed for these 40 dual articulation liners which had functioned in vivo was to the same order as reported for the metal-polyethylene bearing with 22.2 mm femoral heads. Considering the wear on both the convex and concave surface, the dual articulation was not associated with increased wear compared with the conventional metal-polyethylene bearings, but with the advantages of retention and greater stability. CONCLUSION: Use of a dual articulation acetabular liner is an attractive solution when a metal-polyethylene bearing is considered. The benefit in terms of joint stability does not increase wear.

Acetabulum↗