The aim of this study was to compare the migration of the femoral component, five years postoperatively, between patients with a highly cross-linked polyethylene (HXLPE) insert and those with a conventional polyethylene (PE) insert in an uncemented Triathlon fixed insert cruciate-retaining total knee arthroplasty (TKA). Secondary aims included clinical outcomes and patient-reported outcome measures (PROMs). We have previously reported the migration and outcome of the tibial components in these patients. A double-blinded randomized controlled trial was conducted including 96 TKAs. The migration of the femoral component was measured with radiostereometry (RSA) at three and six months and one, two, and five years postoperatively. PROMs were collected preoperatively and at all periods of follow-up.Aims
Methods
The primary outcome was investigating differences in wear, as measured by femoral head penetration, between cross-linked vitamin E-diffused polyethylene (vE-PE) and cross-linked polyethylene (XLPE) acetabular component liners and between 32 and 36 mm head sizes at the ten-year follow-up. Secondary outcomes included acetabular component migration and patient-reported outcome measures (PROMs) such as the EuroQol five-dimension questionnaire, 36-Item Short-Form Health Survey, Harris Hip Score, and University of California, Los Angeles Activity Scale (UCLA). A single-blinded, multi-arm, 2 × 2 factorial randomized controlled trial was undertaken. Patients were recruited between May 2009 and April 2011. Radiostereometric analyses (RSAs) were performed from baseline to ten years. Of the 220 eligible patients, 116 underwent randomization, and 82 remained at the ten-year follow-up. Eligible patients were randomized into one of four interventions: vE-PE acetabular liner with either 32 or 36 mm femoral head, and XLPE acetabular liner with either 32 or 36 mm femoral head. Parameters were otherwise identical except for acetabular liner material and femoral head size.Aims
Methods
The primary objective of this study was to compare the five-year tibial component migration and wear between highly crosslinked polyethylene (HXLPE) inserts and conventional polyethylene (PE) inserts of the uncemented Triathlon fixed insert cruciate-retaining total knee arthroplasty (TKA). Secondary objectives included clinical outcomes and patient-reported outcome measures (PROMs). A double-blinded, randomized study was conducted including 96 TKAs. Tibial component migration and insert wear were measured with radiostereometric analysis (RSA) at three, six, 12, 24, and 60 months postoperatively. PROMS were collected preoperatively and at all follow-up timepoints.Aims
Methods
This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA). Patients undergoing primary THA were recruited from four institutions and prospectively allocated to the following treatment groups: Group A, CoCr femoral head with XLPE liner; Group B, OxZr femoral head with XLPE liner; and Group C, OxZr femoral head with UHMWPE liner. All study patients and assessors recording outcomes were blinded to the treatment groups. The outcomes of 262 study patients were analyzed at ten years’ follow-up.Aims
Methods
Aims. The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA). Methods. We retrospectively evaluated 29 patients (35 hips) who underwent THA between December 2000 and February 2002. The survival rate was estimated using the Kaplan-Meier method. Hip joint function was evaluated using the Japanese Orthopaedic Association (JOA) score. Two-dimensional polyethylene wear was estimated using Martell’s Hip Analysis Suite. We calculated the wear rates between years 1 and 5, 5 and 10, 10 and 15, and 15 and final follow-up. Results. The mean follow-up period was 19.1 years (SD 0.6; 17.3 to 20.1). The 19-year overall survival rate with the end point of all-cause revision was 97.0% (95% confidence interval (CI) 91 to 100). The mean JOA score improved from 43.2 (SD 10.6; 30 to 76) before surgery to 90.2 (SD 6.4; 76 to 98) at the final follow-up (p < 0.001). There was no osteolysis or loosening of the acetabular or femoral components. The overall steady-state wear rate was 0.013 mm/year (SD 0.012). There was no hip with a steady-state wear rate of > 0.1 mm/year. There was no significant difference in wear rates for each period. We found no significant correlation between the wear rate and age, body weight, BMI, or cup inclination. Conclusion. First-generation annealed HXLPE shows excellent
Dual mobility implants in total hip arthroplasty are designed to increase the functional head size, thus decreasing the potential for dislocation. Modular dual mobility (MDM) implants incorporate a metal liner (e.g. cobalt-chromium alloy) in a metal shell (e.g. titanium alloy), raising concern for mechanically assisted crevice corrosion at the modular liner-shell connection. We sought to examine fretting and corrosion on MDM liners, to analyze the corrosion products, and to examine histologically the periprosthetic tissues. A total of 60 retrieved liners were subjectively scored for fretting and corrosion. The corrosion products from the three most severely corroded implants were removed from the implant surface, imaged using scanning electron microscopy, and analyzed using Fourier-transform infrared spectroscopy.Aims
Methods
The most frequent indication for revision surgery in total hip arthroplasty (THA) is aseptic loosening. Aseptic loosening is associated with polyethylene liner wear, and wear may be reduced by using vitamin E-doped liners. The primary objective of this study was to compare proximal femoral head penetration into the liner between a) two cross-linked polyethylene (XLPE) liners (vitamin E-doped (vE-PE)) versus standard XLPE liners, and b) two modular femoral head diameters (32 mm and 36 mm). Patients scheduled for a THA were randomized to receive a vE-PE or XLPE liner with a 32 mm or 36 mm metal head (four intervention groups in a 2 × 2 factorial design). Head penetration and acetabular component migration were measured using radiostereometric analysis at baseline, three, 12, 24, and 60 months postoperatively. The Harris Hip Score, University of California, Los Angeles (UCLA) Activity Score, EuroQol five-dimension questionnaire (EQ-5D), and 36-Item Short-Form Health Survey questionnaire (SF-36) were assessed at baseline, three, 12, 36, and 60 months.Aims
Methods
We have previously demonstrated raised cobalt and chromium levels in patients with larger diameter femoral heads, following metal-on-polyethylene uncemented total hip arthroplasty. Further data have been collected, to see whether these associations have altered with time and to determine the long-term implications for these patients and our practice. Patients from our previous study who underwent Trident-Accolade primary total hip arthroplasties using a metal-on-polyethylene bearing in 2009 were reviewed. Patients were invited to have their cobalt and chromium levels retested, and were provided an Oxford Hip Score. Serum ion levels were then compared between groups (28 mm, 36 mm, and 40 mm heads) and over time.Aims
Methods
We propose a state-of-the-art temporary spacer, consisting of a cobalt-chrome (CoCr) femoral component and a gentamicin-eluting ultra-high molecular weight polyethylene (UHMWPE) tibial insert, which can provide therapeutic delivery of gentamicin, while retaining excellent mechanical properties. The proposed implant is designed to replace conventional spacers made from bone cement. Gentamicin-loaded UHMWPE was prepared using phase-separated compression moulding, and its drug elution kinetics, antibacterial, mechanical, and wear properties were compared with those of conventional gentamicin-loaded bone cement.Aims
Methods
A retrospective study was conducted to measure short-term Nonweightbearing supine RSA exams were performed postoperatively and at six, 12, and 24 months. Weightbearing standing RSA exams were performed on select patients at 12 and 24 months. Wear was measured both linearly (joint space) and volumetrically (digital model overlap) at each available follow-up. Precision of both methods was assessed by comparing double RSA exams. Patient age, sex, body mass index, and Oxford Knee Scores were analyzed for any association with PE wear.Aims
Patients and Methods
Vitamin E-diffused, highly crosslinked polyethylene (VEPE) and porous titanium-coated (PTC) shells were introduced in total hip arthroplasty (THA) to reduce the risk of aseptic loosening. The purpose of this study was: 1) to compare the wear properties of VEPE to moderately crosslinked polyethylene; 2) to assess the stability of PTC shells; and 3) to report their clinical outcomes at seven years. A total of 89 patients were enrolled into a prospective study. All patients received a PTC shell and were randomized to receive a VEPE liner (n = 44) or a moderately crosslinked polyethylene (ModXLPE) liner (n = 45). Radiostereometric analysis (RSA) was used to measure polyethylene wear and component migration. Differences in wear were assessed while adjusting for body mass index, activity level, acetabular inclination, anteversion, and head size. Plain radiographs were assessed for radiolucency and patient-reported outcome measures (PROMs) were administered at each follow-up.Aims
Patients and Methods
The use of vitamin E-infused highly crosslinked polyethylene (HXLPE) in total knee prostheses is controversial. In this paper we have compared the clinical and radiological results between conventional polyethylene and vitamin E-infused HXLPE inserts in total knee arthroplasty (TKA). The study included 200 knees (175 patients) that underwent TKA using the same total knee prostheses. In all, 100 knees (77 patients) had a vitamin E-infused HXLPE insert (study group) and 100 knees (98 patients) had a conventional polyethylene insert (control group). There were no significant differences in age, sex, diagnosis, preoperative knee range of movement (ROM), and preoperative Knee Society Score (KSS) between the two groups. Clinical and radiological results were evaluated at two years postoperatively.Aims
Patients and Methods
The objective of this five-year prospective, blinded, randomised
controlled trial (RCT) was to compare femoral head penetration into
a vitamin E diffused highly cross-linked polyethylene (HXLPE) liner
with penetration into a medium cross-linked polyethylene control
liner using radiostereometric analysis. Patients scheduled for total hip arthroplasty (THA) were randomised
to receive either the study E1 (32 patients) or the control ArComXL
polyethylene (35 patients). The median age (range) of the overall
cohort was 66 years (40 to 76).Aims
Patients and Methods
The aim of this systematic review was to report the rate of dislocation
following the use of dual mobility (DM) acetabular components in
primary and revision total hip arthroplasty (THA). A systematic review of the literature according to the Preferred
Reporting Items for Systematic Reviews and Meta-analyses guidelines
was performed. A comprehensive search of Pubmed/Medline, Cochrane
Library and Embase (Scopus) was conducted for English articles between
January 1974 and March 2016 using various combinations of the keywords “dual
mobility”, “dual-mobility”, “tripolar”, “double-mobility”, “double
mobility”, “hip”, “cup”, “socket”. The following data were extracted
by two investigators independently: demographics, whether the operation
was a primary or revision THA, length of follow-up, the design of
the components, diameter of the femoral head, and type of fixation
of the acetabular component.Aims
Materials and Methods
Recently, the use of metal-on-metal articulations
in total hip arthroplasty (THA) has led to an increase in adverse
events owing to local soft-tissue reactions from metal ions and
wear debris. While the majority of these implants perform well,
it has been increasingly recognised that a small proportion of patients
may develop complications secondary to systemic cobalt toxicity
when these implants fail. However, distinguishing true toxicity
from benign elevations in cobalt ion levels can be challenging. The purpose of this two part series is to review the use of cobalt
alloys in THA and to highlight the following related topics of interest:
mechanisms of cobalt ion release and their measurement, definitions
of pathological cobalt ion levels, and the pathophysiology, risk factors
and treatment of cobalt toxicity. Historically, these metal-on-metal
arthroplasties are composed of a chromium-cobalt articulation. The release of cobalt is due to the mechanical and oxidative
stresses placed on the prosthetic joint. It exerts its pathological
effects through direct cellular toxicity. This manuscript will highlight the pathophysiology of cobalt
toxicity in patients with metal-on-metal hip arthroplasties. Take home message: Patients with new or evolving hip symptoms
with a prior history of THA warrant orthopaedic surgical evaluation.
Increased awareness of the range of systemic symptoms associated
with cobalt toxicity, coupled with prompt orthopaedic intervention, may
forestall the development of further complications. Cite this article:
We report the five-year outcome of a randomised
controlled trial which used radiostereometric analysis (RSA) to assess
the influence of surface oxidised zirconium (OxZr, Oxinium) on polyethylene
wear A total of 120 patients, 85 women and 35 men with a mean age
of 70 years (59 to 80) who were scheduled for primary cemented total
hip arthroplasty were randomly allocated to four study groups. Patients
were blinded to their group assignment and received either a conventional
polyethylene (CPE) or a highly cross-linked (HXL) acetabular component
of identical design. On the femoral side patients received a 28
mm head made of either cobalt-chromium (CoCr) or OxZr. The proximal head penetration (wear) was measured with repeated
RSA examinations over five years. Clinical outcome was measured
using the Harris hip score. There was no difference in polyethylene wear between the two
head materials when used with either of the two types of acetabular
component (p = 0.3 to 0.6). When comparing the two types of polyethylene
there was a significant difference in favour of HXLPE, regardless
of the head material used (p <
0.001). In conclusion, we found no advantage of OxZr over CoCr in terms
of polyethylene wear after five years of follow-up. Our findings
do not support laboratory results which have shown a reduced rate
of wear with OxZr. They do however add to the evidence on the better
resistance to wear of HXLPE over CPE. Cite this article:
Most published randomised controlled trials which
compare the rates of wear of conventional and cross-linked (XL) polyethylene
(PE) in total hip arthroplasty (THA) have described their use with
a cementless acetabular component. We conducted a prospective randomised study to assess the rates
of penetration of two distinct types of PE in otherwise identical
cemented all-PE acetabular components. A total of 100 consecutive patients for THA were randomised to
receive an acetabular component which had been either highly XL
then remelted or moderately XL then annealed. After a minimum of eight years follow-up, 38 hips in the XL group
and 30 hips in the annealed group had complete data (mean follow-up
of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively).
In the XL group, the steady state rate of penetration from one year
onwards was -0.0002 mm/year ( These results show that the yearly linear rate of femoral head
penetration can be significantly reduced by using a highly XLPE
cemented acetabular component. Cite this article:
We have assessed the different adhesive properties
of some of the most common bacteria associated with periprosthetic
joint infection on various types of ultra high molecular Weight
Polyethylene (UHMWPE). Quantitative Cite this article:
We reviewed the literature on the currently available
choices of bearing surface in total hip replacement (THR). We present
a detailed description of the properties of articulating surfaces
review the understanding of the advantages and disadvantages of
existing bearing couples. Recent technological developments in the
field of polyethylene and ceramics have altered the risk of fracture
and the rate of wear, although the use of metal-on-metal bearings has
largely fallen out of favour, owing to concerns about reactions
to metal debris. As expected, all bearing surface combinations have
advantages and disadvantages. A patient-based approach is recommended,
balancing the risks of different options against an individual’s
functional demands. Cite this article:
Hip simulators have been used for ten years to determine the tribological performance of large-head metal-on-metal devices using traditional test conditions. However, the hip simulator protocols were originally developed to test metal-on-polyethylene devices. We have used patient activity data to develop a more physiologically relevant test protocol for metal-on-metal devices. This includes stop/start motion, a more appropriate walking frequency, and alternating kinetic and kinematic profiles. There has been considerable discussion about the effect of heat treatments on the wear of metal-on-metal cobalt chromium molybdenum (CoCrMo) devices. Clinical studies have shown a higher rate of wear, levels of metal ions and rates of failure for the heat-treated metal compared to the as-cast metal CoCrMo devices. However, hip simulator studies in vitro under traditional testing conditions have thus far not been able to demonstrate a difference between the wear performance of these implants. Using a physiologically relevant test protocol, we have shown that heat treatment of metal-on-metal CoCrMo devices adversely affects their wear performance and generates significantly higher wear rates and levels of metal ions than in as-cast metal implants.
