Highly Cross-linked Polyethylene Liner Research Articles

THE ASSOCIATION OF BEARING SURFACE MATERIALS WITH THE RISK OF REVISION FOLLOWING PRIMARY TOTAL HIP ARTHROPLASTY: A COHORT ANALYSIS OF 1,026,481 HIP ARTHROPLASTIES FROM THE NATIONAL JOINT REGISTRY

We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by types of bearing surfaces used.We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with head and shell/liner combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR).A total of 1,026,481 primary THRs performed between 2003–2019 are included in the primary analysis (Monobloc: n=378,979 and Modular: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488).Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the all-cause risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period.Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the all-cause risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period.The all-cause and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is lower for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup than commonly used alternatives such as cobalt chrome heads and HCLPE liner/cup.

BEARING SURFACE MATERIALS AND THE RISK OF REVISION FOLLOWING PRIMARY TOTAL HIP ARTHROPLASTY: A COHORT ANALYSIS OF 1,026,481 HIP ARTHROPLASTIES FROM THE NATIONAL JOINT REGISTRY

Hip bearing surfaces materials are typically broadly reported in national registry (metal-on-polyethylene, ceramic-on-ceramic etc). We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by detailed types of bearing surfaces used.We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with detailed head and shell/liner bearing material combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR).A total of 1,026,481 primary THRs performed between 2003–2019 were included in the primary analysis (Monobloc cups: n=378,979 and Modular cups: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488).Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the overall risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period.Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the overall risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period.The overall and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is reduced for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup in reference to THRs with a cobalt chrome head and HCLPE liner/cup.

Safety of vitamin E-infused highwall liners for routine use in primary total hip arthroplasty: single centre, short-term follow-up of 1221 cases.

Introduction of new implants should be monitored closely to capture any signs of compromising patient safety. Vitamin E infused highly-crosslinked polyethylene liners (VEPE) offer the potential for reduced wear. Highwall liners have been hypothesised to result in increased wear and potential liner fractures. The aim of this study was to determine the 3-7-year follow-up of highwall VEPE for primary total hip arthroplasty (THA), focusing on liner-related complications. We included 1221 consecutive THA operations from July 2010 to May 2014 with minimum follow-up of 3 (3.1-6.8) years Data collected included demographics, implant data, complications, reoperations, and deaths. Data were cross-referenced with the Danish Hip Arthroplasty Registry in order to ensure validity and completeness. Acetabular shell position was measured using Martell Hip Analysis Suite in a subgroup of 931 THAs. Cumulative stem revision and shell revision at 3-year follow-up was 3.4% and 0.4% respectively. There were no revisions due to liner failure. Reason for revision included 11 dislocations, 15 soft-tissue revisions for infection, 44 stem revisions of which 34 were periprosthetic fractures and 13 shell revisions of which 6 were combined shell and stem revisions. Early follow-up of VEPE liners for primary THA have not shown any revisions associated with liner failure. Continued monitoring of new materials are necessary to capture any signs of compromised patient safety.

Mid- to Long-Term Survivorship Analysis of a Second-Generation Highly Cross-Linked Polyethylene in Total Hip Arthroplasty

AbstractThe emergence of highly cross-linked polyethylene (HCLPE) has drastically improved survivorship of implants used in total hip arthroplasty (THA), as demonstrated by midterm outcomes. However, there is limited data evaluating long-term outcomes and wear rates of these liners. Therefore, the aim of this study is to evaluate the longest-to-date follow-up of a specific second-generation HCLPE liner, the progression of wear rate, and its relation to acetabular cup positioning. A retrospective study was conducted on patients who underwent THA between January 2001 and December 2005 using a specific second-generation HCLPE liner. Annual liner wear rate (mm/year) was calculated in this group as well as acetabular positioning through abduction angle (degrees). Failures and reason for failures such as periprosthetic fracture, dislocation, and osteolysis were noted when applicable. Forty hips of 35 patients were included in this study with a clinical and radiographic follow-up of 13.4 ± 2.2 years (range: 10.0–16.7 years). Linear and volumetric wear rates were calculated to be 0.037 ± 0.020 mm/year and 22.94 ± 12.07 mm3/year, respectively. No radiographic femoral or acetabular osteolysis was observed in any of the cases. One patient required revision due to complications unrelated to the liner. No significant relationship could be established for acetabular component abduction angle and linear wear rate (p = 0.690, Spearman's rho = 0.03). Our study demonstrates comparable liner wear rates to that of other second-generation HCLPE liners in long-term follow-up. The XLPE liner continues to exhibit minimal progression of linear wear when compared with previous midterm studies and maintains a low rate of postoperative complications requiring revision THA surgery. Further studies are warranted to assess long-term wear and survivorship between this specific liner and comparable HCLPE models.

Up to 18-Year Follow-Up Wear Analysis of a First-Generation Highly Cross-Linked Polyethylene in Primary Total Hip Arthroplasty

BackgroundThe advent of highly cross-linked polyethylene (HCLPE) has significantly improved total hip arthroplasty survivorship. HCLPE has been shown to improve wear properties in midterm outcomes when compared to traditional polyethylene liners; however, there is a paucity of studies evaluating long-term outcomes. In addition, there is concern that wear rates may accelerate as the implant ages. Thus, the aims of this study are to report on the longest-to-date follow-up of a specific first-generation HCLPE liner and to determine whether there is a change in the annual wear rate over time. MethodsForty hips in 38 patients which were previously reported on in a midterm study were included in this long-term follow-up study. Patients in this cohort all received total hip arthroplasty between March 1999 and August 2004 using the Crossfire HCLPE liner. Annual wear rates (mm/y) were calculated for this cohort. Patients were contacted and asked about complications or revision procedures they may have had since the index procedure. ResultsClinical follow-up averaged 12.9 years with a range of 7-18 years. The average follow-up duration was 12.5 years with a range of 10-17 years. Linear wear was found to be 0.056 ± 0.036 mm/y. Osteolysis was not observed in any of the patients with greater than 10-year radiographic follow-up. Furthermore, only 1 patient required revision surgery following a mechanical fall. ConclusionOur study demonstrates the long-term wear rates associated with HCLPE liners continue to match rates published in midterm studies. Previously, we have reported that this cohort had an average annual wear rate of 0.05 mm/y over 10 years. This most recent report demonstrates a similar wear rate with up to 18-year follow-up.

Wear Kinetics of Highly Cross-Linked and Conventional Polyethylene Are Similar at Medium-term Follow-Up After Primary Total Hip Arthroplasty

BackgroundWear debris is a major factor in aseptic loosening of total hip arthroplasty. Ultra high molecular weight polyethylene inlays are known for significant wear, and the following generation, highly cross-linked polyethylene (HCLPE), has shown promising in vitro and short-term in vivo results. This study aimed to investigate wear debris of HCLPE liners with ceramic heads after 9 years to reveal the in vivo wear kinetics of this common bearing combination. MethodsFifty-seven patients (72 hips; 46.5 ± 15.5 years; range 16-76 years) who underwent hip arthroplasty with an HCLPE liner (28- or 32-mm Biolox forte ceramic head) were followed up (mean 9.1 ± 2.4 years; range 3.9-13.8 years). Conventional anteroposterior X-rays were analyzed using Hip Analysis Suite software. ResultsVolumetric wear had a mean of 38.67 ± 22.09 mm3/year, 333.08 ± 183.93 mm3 overall, and linear wear was 0.063 ± 0.03 mm/year and 0.546 ± 0.27 mm overall. Male patients had a significantly higher wear rate (46.42 ± 27.68 mm3/year) and total wear (400.71 ± 235.21 mm3). Larger femoral heads had a significantly higher wear rate (43.10 ± 23.93 mm3/year) and total wear (364.23 ± 203.68 mm3). Regression analysis showed a significant cubic relationship (R2 = 0.307) with increasing yearly wear after approximately 108 months postoperatively. ConclusionsHCLPE liners show significant in vivo wear after 9 years. While the total wear compared to ultra high molecular weight polyethylene liners was decreased, the wear kinetics show a comparable course. The increase in wear rate after only 108 months postoperatively is especially alarming. Longer term follow-up is needed to distinguish the long-term superiority of HCLPE liners in polyethylene-ceramic paired hip arthroplasty.

10-Year Follow-Up Wear Analysis of Marathon Highly Cross-Linked Polyethylene in Primary Total Hip Arthroplasty

BackgroundShort-term and intermediate-term wear rates for highly cross-linked polyethylene (HCLPE) liners in total hip arthroplasty (THA) are significantly lower than published rates for traditional polyethylene liners. The aim of this study was to report the longest-to-date follow-up of a specific HCLPE liner. MethodsA series of 35 THAs using a specific HCLPE liner were reviewed. Anteroposterior radiographs were reviewed for femoral head penetration, the presence of femoral and/or acetabular osteolysis, long-term survival, total wear, and wear rates in all patients. ResultsThe average patient age at time of surgery was 70 years with an average follow-up of 10 years (118 months; range, 7.2-13.4 years). The mean wear rate in our cohort was 0.07 mm/y. Total wear was 0.71 mm over the study period. No hips showed evidence of osteolysis in any zones. Survivorship at latest follow-up was 100% with all-cause revision as an end point. ConclusionThe wear rate of HCLPE liners continues to be lower than published wear rates for traditional polyethylene and continues to reaffirm the acceptably low wear rates using HCLPE acetabular liner in primary THA.

Polymerizing Bone Cement can Roughen a Polyethylene Bearing Surface on Total Hip Replacement A Surface Analysis

The tribological behaviour of the bearing surface in hip arthroplasty is greatly influenced by its surface roughness. During cemented hip arthroplasty, bone cement may contaminate the bearing surface. Hence, the aim of this study was to investigate the effect of cement polymerization on a highly cross-linked polyethylene(HCLP) bearing surface as any process influences the surface roughness of the bearing surface can have potential long term effect on the wear rate. Three new HCLP liners were used. A map of the surface topography of each liner was obtained using a white light interferometric microscope at five different locations in accordance with the standard BSEN ISO 4288:1998. Bone cement was then applied to the bearing surface and allowed to polymerise, then removed and irrigated with saline. The surface roughness measurement procedure was repeated again for all samples. The Ra results showed a 21% increase in mean surface roughness after cement contamination (p=0.01). The average Ra value pre-contamination was 190 nm while post-contamination was 230 nm. There were also changes in the surface topography observed with 3D surface mapping. Our study indicates that bone cement contamination of the HCLP surface can significantly increase its surface roughness and alter its surface topography. Surgeons should be aware of this potentially serious effect on the bearing and be vigilant to avoid bone cement contamination during arthroplasty surgery.

Effect of Acetabular Orientation on Stress Distribution of Highly Cross-linked Polyethylene Liners

Several case reports have documented the fracture of highly cross-linked polyethylene (HCLPE) liners used in total hip arthroplasty (THA). Although uncommon, fractured liners result in considerable morbidity for patients and require revision surgery. One postulated mechanism that leads to this type of implant failure is malorientation of the acetabular component. The purpose of this study was to investigate the effect of acetabular orientation on the stress distribution of HCLPE liners used in THA by means of finite element analysis. Three-dimensional models of a commonly used HCLPE liner were created corresponding to 12 different acetabular component orientations (inclination ranging from 20° to 70° and version ranging from 20° of retroversion to 40° of anteversion). A static stress analysis of the finite element models was performed under conditions simulating peak gait loads. The results of the analysis revealed that excessive inclination and extremes of version were associated with an increase in peak stress magnitudes. The locations of peak stress also were found to lie within the rim notch and locking ring groove regions, which were consistent with the fracture locations reported in published case reports. Therefore, the acetabular component should be oriented carefully during implantation to reduce the risk of rim loading and subsequent liner fracture. In addition, an alternative liner design may further help reduce stress risers and risk of fracture.

Wear is Reduced in THA Performed with Highly Cross-linked Polyethylene

Highly cross-linked polyethylene (HCLPE) has been used extensively to decrease osteolysis and related implant failure in THA. We compared the wear rate of HCLPE and noncross-linked conventional PE (CPE) liners and the rate of radiographic calcar resorption and osteolysis in young patients (35-60 years of age) who underwent THA by one surgeon. Thirty-four patients (41 THAs) who received a hybrid THA using a HCLPE liner were match-paired for age, gender, body mass index, and diagnosis with a group of patients who underwent THA with identical implants but with a CPE liner. The minimum followup was 4 years (average, 5.3; range, 4-8 years). Using the Livermore measurement technique, the averages of total wear of the HCLPE and CPE liners were 0.01 mm (range, -0.23-0.4) and 0.64 mm (range, 0-1.7), respectively. The average annual wear was less for the HCLPE than the noncross-linked PE (0.002 mm, range, -0.05-0.1 versus 0.12 mm, range, 0-0.29, respectively). Four hips in the HCLPE group and 23 in the CPE group had calcar resorption measuring averages of 2.5 mm (range, 2-3) and 7.5 mm (range, 1.8-23.8), respectively. Periprosthetic osteolysis occurred in two and eight hips in the HCLPE and CPE groups, respectively. Longer followup is needed to determine if these findings will result in improved implant survivorship. Level III, therapeutic study.