Dataset Information

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

ABSTRACT:

Background

Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them.

Questions/purposes

We describe a method for extracting polyethylene wear particles from bovine serum typically used in wear tests and for characterizing their size, distribution, and morphology.

Methods

Serum proteins were completely digested using an optimized enzymatic digestion method that prevented the loss of the smallest particles and minimized their clumping. Density-gradient ultracentrifugation was designed to remove contaminants and recover the particles without filtration, depositing them directly onto a silicon wafer. This provided uniform distribution of the particles and high contrast against the background, facilitating accurate, automated, morphometric image analysis. The accuracy and precision of the new protocol were assessed by recovering and characterizing particles from wear tests of three types of polyethylene acetabular cups (no crosslinking and 5 Mrads and 7.5 Mrads of gamma irradiation crosslinking).

Results

The new method demonstrated important differences in the particle size distributions and morphologic parameters among the three types of polyethylene that could not be detected using prior isolation methods.

Conclusion

The new protocol overcomes a number of limitations, such as loss of nanometer-sized particles and artifactual clumping, among others.

Clinical relevance

The analysis of polyethylene wear particles produced in joint simulator wear tests of prosthetic joints is a key tool to identify the wear mechanisms that produce the particles and predict and evaluate their effects on periprosthetic tissues.

SUBMITTER: Billi F

PROVIDER: S-EPMC3254734 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Publications

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

Billi Fabrizio F Benya Paul P Kavanaugh Aaron A Adams John J Ebramzadeh Edward E McKellop Harry H

Clinical orthopaedics and related research 20120201 2

<h4>Background</h4>Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them.<h4>Questions/purposes</h4>We describe a method for extracting polyethylene wear particles from bovine serum typically used in wear tests and for characterizing their size, distribution, and morphology.<h4>Methods</h4>Serum proteins were completely digested using an optimi ...[more]

PMID: 21997780

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Project description:BackgroundStructural hip deformities including developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) are thought to predispose patients to degenerative joint changes. However, the natural history of these malformations is not clearly delineated.Questions/purposes(1) Among patients undergoing unilateral THA who have a contralateral hip without any radiographic evidence of hip disease, what is the natural history and progression of osteoarthritis in the native hip based on morphological characteristics? (2) Among patients undergoing unilateral THA who have a contralateral hip without any radiographic evidence of hip disease, what are the radiographic parameters that predict differential rates of degenerative change?MethodsWe identified every patient 55 years of age or younger at our institution who received unilateral primary THA from 1980 to 1989 (n = 722 patients). Preoperative radiographs were reviewed on the contralateral hip and only hips with Tönnis Grade 0 degenerative change that had minimum 10-year radiographic followup were included. A total of 172 patients met all eligibility criteria with the following structural diagnoses: 48 DDH, 74 FAI, and 40 normal morphology, and an additional 6% (10 of the 172 patients) met all eligibility criteria but were lost to followup before the 10-year minimum. Mean age at the time of study inclusion was 47 years (range, 18-55 years), and 56% (91 of 162) of the patients in this study were female. Mean followup was 20 years (range, 10-35 years). Radiographic metrics, in conjunction with the review of two experienced arthroplasty surgeons, determined the structural hip diagnosis as DDH, FAI, or normal morphology. Every available followup AP radiograph was reviewed to determine progression from Tönnis Grade 0 to 3 until the time of last followup or operative intervention with THA. Survivorship was analyzed by Kaplan-Meier methodology, hazard ratios, and multistate modeling. Thirty-five patients eventually underwent THA: 16 (33%) DDH, 13 (18%) FAI, and six (15%) normal morphology.ResultsDegenerative change was most rapid in patients with DDH followed by FAI and normal morphology. Among patients who recently developed Tönnis 1 degenerative change, the probability of undergoing THA in 10 years based on hip morphology was approximately one in three for DDH and one in five for both FAI and normal morphology hips, whereas the approximate probability at 20 years was two in three for DDH and one in two for both FAI and normal morphology hips. The likelihood of radiographic degeneration was increased in patients with the following findings: femoral head lateralization > 8 mm, femoral head extrusion index > 0.20, acetabular depth-to-width index < 0.30, lateral center-edge angle < 25°, and Tönnis angle > 8°.ConclusionsDegenerative change occurred earliest in patients with DDH, whereas the natural history of patients with FAI was quite similar to structurally normal hips. However, patients with cam deformities and concomitant acetabular dysplasia developed osteoarthritis more rapidly. Although the results of this study cannot be directly correlated to highly active patients with FAI, these findings suggest that correction of FAI to a normal morphology may only minimally impact the natural history, especially if intervention takes place beyond Tönnis 0. Analysis of radiographic parameters showed that incremental changes toward dysplastic morphology increase the risk of degenerative change.Level of evidenceLevel III, prognostic study.

Project description:BACKGROUND:The choice of surgical approach for THA remains controversial. Some studies suggest that the direct anterior approach (DAA) leads to less muscle damage than the miniposterior approach (MPA), but there is little high-quality evidence indicating whether this accelerates recovery, or whether this approach-which may be technically more demanding-is associated with component malposition or more complications. QUESTIONS/PURPOSES:(1) Does the DAA result in faster return to activities of daily living than the MPA? (2) Does the DAA have superior patient-reported outcome measures than the MPA? (3) Does the DAA result in improved radiographic outcomes than the MPA? (4) Does the DAA have a higher risk of complications than the MPA? METHODS:Between March 1, 2013, and May 31, 2016, 116 patients undergoing primary unilateral THA were randomized to either the DAA or MPA; 15 patients withdrew after randomization, and one died 6 months after surgery from a stroke unrelated to the procedure. Recruitment stopped when 52 patients had been randomized into the DAA group and 49 in the MPA group (n = 101). After patient randomization, one high-volume surgeon performed all of the DAAs and three high-volume surgeons performed the MPA THAs. The groups did not differ in age (65 years; SD 11; range, 38-86 years), sex (52% women), or body mass index (mean 29 kg/m; SD 6 kg/m; range, 21-40 kg/m; all p > 0.40). Functional results included time to discontinue gait aids, discontinue all narcotics, and independence with various activities of daily living; accelerometer data evaluated activity level. Clinical and radiographic outcomes, Hip disability and Osteoarthritis Outcome Score, SF-12, and Harris hip scores to 1 year were also tabulated. The minimum followup was 365 days (mean ± SD, 627 ± 369 days). RESULTS:There were slight differences in early functional recovery that favored the DAA versus the MPA: time to discontinue walker use (10 versus 15 days, p = 0.01) and time to discontinue all gait aids (17 versus 24 days, p = 0.04). There were no other differences in early functional milestones, although at 2 weeks after surgery, mean steps per day were 3897 (SD 2258; range, 737-11,010) for the DAA versus 2235 for the MPA (SD 1688; range, 27-7450; p < 0.01). There was no difference in activity monitoring at 1 year. There were no differences in patient-reported outcome scores between the groups. There was no difference in the radiographic parameters measured in the two groups, including leg length discrepancy, component position, or offset, and there was no subsidence observed in any hip. There was no difference in complications between the DAA and the MPA groups (8% [four of 52] versus 10% [five of 49]; p = 0.33). CONCLUSIONS:Both the DAA and MPA approaches provided excellent early recovery with a low risk of complications. Patients undergoing the DAA had a slightly faster recovery, as measured by milestones of function and quantified by activity monitor data, but no substantive differences were evident at 2 months. Because the DAA is the less studied approach, longer term (> 1 year) complications may yet accrue, will be important to quantify, and may offset early benefits. LEVEL OF EVIDENCE:Level I, therapeutic study.

Project description:BackgroundWear, oxidation, and particularly rim impingement damage of ultra-high molecular weight polyethylene total disc replacement components have been observed following surgical revision. However, neither in vitro testing nor retrieval-based evidence has shown the effect(s) of impingement on the characteristics of polyethylene wear debris. Thus, we sought to determine (1) differences in polyethylene particle size, shape, number, or biological activity that correspond to mild or severe rim impingement and (2) in an analysis of all total disc replacements, regardless of impingement classification, whether there are correlations between the extent of regional damage and the characteristics of polyethylene wear debris.MethodsThe extent of dome and rim damage was characterized for eleven retrieved polyethylene cores obtained at revision surgery after an average duration of implantation of 9.7 years (range, 4.6 to 16.1 years). Polyethylene wear debris was isolated from periprosthetic tissues with use of nitric acid and was imaged with use of environmental scanning electron microscopy. Subsequently, particle size, shape, number, biological activity, and chronic inflammation scores were determined.ResultsGrouping of particles by size ranges that represented high biological relevance (<0.1 to 1-μm particles), intermediate biological relevance (1 to 10-μm particles), and low biological relevance (>10-μm particles) revealed an increased volume fraction of particles in the <0.1 to 1-μm and 1 to 10-μm size ranges in the mild-impingement cohort as compared with the severe-impingement cohort. The increased volume fractions resulted in a higher specific biological activity per unit particle volume in the mild-impingement cohort than in the severe-impingement cohort. However, functional biological activity, which is normalized by particle volume (mm3/g of tissue), was significantly higher in the severe-impingement cohort. This increase was due to a larger volume of particles in all three size ranges. In both cohorts, the functional biological activity correlated with the chronic inflammatory response, and the extent of rim penetration positively correlated with increasing particle size, number, and functional biological activity.ConclusionsThe results of this study suggest that severe rim impingement increases the production of biologically relevant particles from motion-preserving lumbar total disc replacement components.Level of evidencePrognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Dataset Information

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

Background

Questions/purposes

Methods

Results

Conclusion

Clinical relevance

Publications

The John Charnley Award: an accurate and sensitive method to separate, display, and characterize wear debris: part 1: polyethylene particles.

Similar Datasets

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