Linear Polyethylene Wear Rate Research Articles

Total Hip Arthroplasty in Patients 21 Years and Younger Using Highly Cross-Linked Polyethylene: Excellent Survivorship at Five Years

AbstractThe survivorship of contemporary total hip arthroplasty has improved substantially as a result of the success of highly cross-linked polyethylene. Nevertheless, there is limited information on its performance in extremely young patients. The purpose of this study is to evaluate the (1) clinical and radiographic outcomes, (2) polyethylene wear rates, and (3) mid-term survivorship of total hip arthroplasty in patients 21 years or younger using highly cross-linked polyethylene. After Institutional Review Board approval, the authors identified 45 patients aged 21 years or younger (56 hips) who underwent primary total hip arthroplasty with highly cross-linked polyethylene at their institution by the senior author between 2000 and 2009. Patients were followed for a minimum of 2 years, or until revision. At a mean follow-up of 57 months, modified Harris Hip Scores, Western Ontario McMaster Universities Arthritis Index scores, Short Form-12 physical function scores, and University of California, Los Angeles activity scores improved significantly in all patients. There was no radiographic evidence of osteolysis in any patient. The mean linear polyethylene wear rate was 0.02 mm per year. Survivorship was 98% with one revision for acetabular loosening at 71 months. Total hip arthroplasty in patients 21 years or younger with highly cross-linked polyethylene had excellent clinical and radiographic outcomes at mid-term follow-up. Longer-term data are needed in this patient population to confirm continued survivorship in the extremely young. The level of evidence used for this study was level III.

Comment on Langlois et al.: Charnley-Kerboull total hip arthroplasty combining zirconia on polyethylene. A minimum eight-year follow-up prospective study

To the Editor, We read the article entitled “Charnley-Kerboull total hip arthroplasty combining zirconia on polyethylene. A minimum eight-year follow-up prospective study” by Langlois et al. [1] with great interest. We appreciate this follow-up study in which the authors performed an open prospective clinical trial involving 51 consecutive patients (55 hips) with Charnley-Kerboull all-cemented hip arthroplasty. Their study confirms earlier short-terms results, and demonstrates that zirconia should no longer be used in total hip arthroplasty. There are three queries which we would like to refer to the authors. The authors started their radiological evaluations at six weeks after the total hip arthroplasty. This means that the first radiograph they used for analysis was the one carried out 1.5 months after the primary total hip arthroplasty. If earlier postoperative radiographs could be available, for example, in the first day after the surgery, then a more precise calculation of linear polyethylene wear rate could be obtained. In the Results section, the authors use a parameter of mean linear penetration rate to describe wear and tear of prosthesis. However, we consider that both the mean linear polyethylene wear rate and mean volumetric polyethylene wear rate are important to evaluate the wear results [2]. Therefore, we would like to know the reason why the authors just chose the former for all analyses. In Fig. 3, the radiograph made at 121-month follow-up shows continuous radiolucency at the bone–cement interface, distal lateral shift of the stem. The authors told us that some patients suffered from thigh pain. As we know, severe thigh pain is one of the important symptoms which leads to revision surgery [3]. However, the description of thigh pain was not mentioned in other parts of the article. So, we would like to make an enquiry about thigh pain incidence of patients in this follow-up study. We agree with the authors that in vitro results of a material should be projected with extreme caution to its in vivo behaviour.

Femoral Head Size and Wear of Highly Cross-linked Polyethylene at 5 to 8 Years

Wear of highly cross-linked polyethylene is reportedly independent of head size. To confirm that observation we asked in our population whether head size related to wear with one type of electron beam highly cross-linked polyethylene. Of 146 hips implanted, we evaluated complete clinical and radiographic data for 90 patients (102 hips or 70%). The minimum followup was 5 years (mean, 5.7 years; range, 5-8 years). The head size was selected intraoperatively based on the size of the acetabular component and presumed risk of dislocation. Polyethylene wear measurements were performed in one experienced laboratory using the method of Martell et al. There was no hip with pelvic or femoral osteolysis. The median linear wear rate was 0.028 mm/year (mean, 0.04 mm/year), and the median volumetric wear rate was 25.6 mm(3)/year (mean, 80.5 mm(3)/year). Median total volumetric wear was 41.0 mm(3) (mean, 98.5 mm(3)). We found no association between femoral head size and the linear wear rate, but observed an association between larger (36- and 40-mm) head size and volumetric wear rate and total volumetric wear. Although the linear wear rate of polyethylene was not related to femoral head diameter, there was greater volumetric wear (156.6 mm(3)/year) with the 36- and 40-mm heads. Pending long-term studies of large head sizes, we advise caution in using larger femoral heads in young or active patients and in those with a low risk of dislocation. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The use of cementless expansion acetabular component and an alumina-polyethylene bearing in total hip arthroplasty for osteonecrosis

We performed 114 consecutive primary total hip arthroplasties with a cementless expansion acetabular component in 101 patients for advanced osteonecrosis of the femoral head. The mean age of the patients at surgery was 51 years (36 to 62) and the mean length of follow-up was 110 months (84 to 129). The mean pre-operative Harris hip score of 47 points improved to 93 points at final follow-up. The polyethylene liner was exchanged in two hips during this period and one broken acetabular component was revised. The mean linear wear rate of polyethylene was 0.07 mm/year and peri-acetabular osteolysis was seen in two hips (1.9%). Kaplan-Meier analysis indicated that the survival of the acetabular component without revision was 97.8% (95% confidence interval 0.956 to 1.000) at ten years. Our study has shown that the results of THA with a cementless expansion acetabular component and an alumina-polyethylene bearing surface are good.

Polyethylene Wear and Osteolysis in Uncemented Acetabular Component

Purpose: To investigate the influence of the linear wear rate of polyethylene, the osteolysis threshold of the linear wear rate, and the related factors on polyethylene wear in an uncemented metal-backed-cup of a primary total hip arthroplasty. Materials and Methods: This study examined 87 hips from 75 patients (57 men and 18 women) who had undergone a primary total hip arthroplasty with a minimum follow-up of five years. The mean age was 47.3 years (range, 25-68 years). The mean follow up period was 90 months (range, 60-148 months). The most frequent diagnosis was avascular necrosis of the femoral head. 18 Harris-Galante I and 69 Harris-Galante II cups, were used on the acetabular side, and 66 Anatomic and 21 Harris-Galantestems were used on the femoral side. Radiographic polyethylene wear was estimated using the method reported by Livermore, and the above mentioned factors that influence polyethylene wear were investigated and analyzed statistically. Results: The overall mean linear wear rate of polyethylene was 0.21 mm/year. The linear wear rate of 22 hips with osteolysis and 65 hips without osteolysis was 0.29 mm/year and 0.12 mm/year respectively, showing a significant difference (p=0.001). The patients with high activity had a significantly higher mean linear wear rate (0.28 mm/year) than that those patients with low activity (0.16 mm/year) (p=0.048). Patients younger than 40 year-old had a significantly higher mean linear wear rate (0.23 mm/year) than the patients older than 40 year-old (0.19 mm/year) (p=0.049). However, there were no correlations between the mean linear wear rate and gender, weight, diagnosis, the type of cup and the thickness of the polyethylene. Conclusion: The polyethylene wear rate in an uncemented metal-backed-cup was significantly affected by age and the activity of the patients, which strongly influenced the development of osteolysis. Therefore, in order to reduce the incidence of aseptic loosening due to osteolysis in young patients with high activity, a bearing surface with mean linear wear rate of 0.12 mm/year or less is recommended.

Total Hip Arthroplasty for the Treatment of Osseous Ankylosed Hips

The long-term results of total hip prostheses in 86 patients (87 hips) who had either primary cemented or cementless total hip arthroplasty after fusion take-down were analyzed. Thirty-eight patients (38 hips) had a surgical fusion and 48 patients (49 hips) had a spontaneous fusion. The mean age of patients was slightly older in the cemented group (49.8 years) than in the cementless group (43.8 years). Twenty-six of 42 patients (62%) in the cemented group and 32 of 44 patients (73%) in the cementless group were younger than 50 years. Clinical (Harris hip rating system) and radiographic evaluations were done preoperatively and at 6 weeks, at 3, 6, and 12 months, and yearly thereafter. The average followup was 10.2 years (range, 8-18 years) in the cemented group and 9.8 years (range, 8-17 years) in the cementless group. The revision rates were 16% in the patients who had surgical fusion and 18% in the patients who had spontaneous fusion. The revision rates were 17% in the cemented group and 18% in the cementless group. The average linear wear rate of polyethylene per year was 0.24 mm in the cemented group and 0.32 mm in the cementless group. The incidence of osteolysis was 52% in the cemented group and was 58% in the cementless group.

Nonmodular One-Unit Cementless Acetabular Compoment in Primary Total Hip Arthroplasty: With Alumina to Polyethylene Articulation

Purpose : Modular acetabular components have the potential of fretting and back side wear leading to osteolysis. The present study evaluated the outcomes of total hip arthroplasties (THAS) using a nonmodular cementless acetabular component with those of press-fit titanium mesh coatings fixed. Materials and Methods : Eighty-two primary THAS in 75 patients were performed consecutively between April 1995 and August 1998. Sixtytwo hips were eligible for follow up for an average 62 months. Mean patients age was 59 years. The clinical evaluation was performed using the modified Harris hip score (HHS), inguinal pain and limping. The radiologic evaluation included, component stability, polyethylene wear rate, pelvic osteolysis and the remodeling pattern around the acetabular component. Results : Mean HHS improved from 50.2 points preoperatively to 90.5 points at the most recent follow up. All components were stable radiologically. The linear polyethylene wear rate was 0.07 mm/year. No pelvic osteolysis was found. Polar gaps found in 25 hips (40%) in postoperative radiographs and disappeared during follow up in 22 hips (88%). One hip was revised due to chronic unreduced dislocation. Conclusion : Total hip arthroplasty with a nonmodular cementless acetabular component seems to enhance satisfactory early mid-term results in terms of stability and acetabular remodeling with minimal wear and pelvic osteolysis.

Primary Total Hip Arthroplasties Using Harris-Galante Porous Coated Cementless Prosthesis: Mean 10-Year Follow-Up Results

Purpose : The purpose of this study was to analyze the intermediate to long-term results of primary total hip arthroplasties with a Harris-Galante prosthesis. Materials and Methods : Among 97 consecutive total hip replacements with Harris-Galante prosthesis in 85 patients, 76 hips in 67 patients were evaluated clinically and roentgenographically. The mean follow-up was for 10.1 years (range 6.2-13 years). Clinical and radiographic evaluations including osteolysis, stability of prosthesis, and wear of polyethylene were performed. Statistical analysis was conducted to find the relevant factors influencing osteolysis. The survivorship of overall and each acetabular and femoral component was analyzed by Kaplan-Meier method. Results : The Harris hip score averaged 44 points at preoperatively and improved to 89 points at the most recent follow-up. Pelvic osteolysis was found in 3 hips (4%) and femoral osteolysis was found in 32 (42%). The linear polyethylene wear rate was averaged 0.13 mm/year. Nine femoral components and two acetabular components were revised. There were 2 recurrent dislocations, 3 periprosthetic fractures and 4 infections. The probability of survival of the femoral and acetabular component at a mean 10 years was 81% (range 71- 93%) and 96% (range 91-100%) by the Kaplan-Meier method. Conclusion : The intermediate to long-term follow up of primary total hip arthroplasty with Harris-Galante prosthesis revealed a low failure rate of acetabular component and a relatively high failure rate of the femoral component which was usually related with loosening and osteolysis.

The Harris-Galante Porous Acetabular Component at Intermediate Follow-Up

Outcome of the acetabular component in 90 consecutive primary noncemented total hip arthroplasties (THAs) was prospectively studied. The acetabular cup consisted of a hemispherical titanium alloy shell with a titanium fiber-mesh porous coating and a modular polyethylene liner (Harris-Galante Porous-1, Zimmer, Warsaw, Ind). The cup was implanted using line-to-line reaming with adjunctive dome screw fixation. The femoral component consisted of a titanium alloy stem with titanium fiber-mesh porous coating and a 28-mm cobalt-chrome modular head. Mean patient age was 53 years (range: 27-75 years); male:female ratio was 48:42; and mean follow-up was 6 years (range: 4.5-8 years). One acetabular component was revised for aseptic loosening. Of 81 unrevised hips available for follow-up, mean Harris hip score was 57 preoperatively and 96 at final follow-up (72% excellent, 15% good, 1 3% fair, and none poor). Of 61 unrevised hips with adequate radiographic follow-up, radiographic failure (complete periprosthetic radiolucency) was evident in 3 (4.9%) and periacetabular osteolysis in none. Radiographic failure did not correlate with poor clinical outcome. Linear polyethylene wear rate (mean: 0.13 mm/year) did not correlate with age, gender, weight, outcome, or cup abduction angle, but did correlate with the presence of femoral periprosthetic osteolysis (0.18 mm/year with femoral osteolysis versus 0.11 mm/year without; P= .01). This series of porous-coated hemispherical cups demonstrated excellent intermediate-term clinical and radiographic outcome, comparable with similarly favorable results reported by the prosthesis designers. A potentially adverse effect of polyethylene wear on the longevity of a THA was supported by a positive correlation between polyethylene wear rate and femoral osteolysis.

Poor outcome of 44 cemented total hip arthroplasties with alumina ceramic heads: clinical evaluation and retrieval analysis after 10-16 years.

We evaluated the long-term results of cemented total hip arthroplasty with alumina ceramic heads in 39 patients (44 hips) from 1981 to 1985. The study comprised 8 men (8 hips) and 31 women (36 hips). Their mean age was 54 (37-76) years and mean weight 52 (34-93) kg. The preoperative diagnoses were osteoarthrosis in 34 patients (38 hips), rheumatoid arthritis in 3 (4 hips) and idiopathic osteonecrosis of the femoral head in 2 (2 hips). The mean duration of follow-up was 13 (10-16) years. At this time, 6 cases had been revised because of aseptic loosening (5 hips showed loosening of both components and 1 acetabular loosening alone). Kaplan-Meier survivorship analysis with radiographic loosening as end-point showed 10-year survival rates of 75% for the acetabular component and 86% for the femoral. The mean linear wear rate of polyethylene was 0.10 mm/year radiographically--i.e., about the same as reported for many metal to polyethylene bearings. 5 alumina ceramic heads were retrieved and showed excellent surface roughness and roundness without scratches. However, debris stuck to the gaps was detected. The debris may act as third-bodies and affect polyethylene wear.

Fixation, polyethylene wear, and pelvic osteolysis in primary total hip replacement.

A multicenter retrospective review was performed analyzing 1081 primary total hip replacements in 944 patients using the Harris Galante-I cementless acetabular component with screw fixation. All patients were followed up for a minimum of 5 years with a mean followup of 81 months. Linear polyethylene wear averaged 0.11 mm/year (range, 0-0.86 mm/year). Pelvic osteolysis was seen in 25 patients (2.3%). Migration of the acetabular component was seen in four hips. A subgroup of patients was reanalyzed at a minimum followup of 10 years. The mean linear polyethylene wear rate remained 0.11 mm/year. In this group, only one socket had migrated. There was an association between wear rate and age. On average, younger patients had higher wear rates. The risk for having pelvic osteolysis develop and the need for revision surgery also was age-related. Twenty-two percent of hip replacements (15 hips) in patients younger than 50 years of age at the time of their index operation had pelvic osteolysis develop. In contrast, for patients older than 50 years of age at the time of surgery only 7.8% (eight hips) had osteolysis of the pelvis develop. For patients older than 70 years of age at the time of primary total hip replacement, none had pelvic osteolysis develop.

Precoated femoral component in total hip arthroplasty. Results of 5- to 9-year followup.

One hundred nineteen consecutive primary hybrid total hip arthroplasties with a precoated femoral component were performed by one surgeon in 100 patients and followed up prospectively. Ninety-eight hips in 82 patients (mean age, 67 years) were evaluated clinically and radiographically at a mean of 6.5 years (range, 5-9 years). The hips were evaluated clinically using the Harris hip score, and radiographs were evaluated for femoral cement grade, loosening, and osteolysis. Ninety-five hips remained in place at the most recent followup. Two femoral components were revised for definite loosening, and one well fixed femoral component was removed because of late hematogenous infection. Excluding the three hips that were revised, the clinical result was excellent or good in 79 hips (83%), fair in 12 hips (13%), and poor in four hips (4%). All other femoral components were well fixed. There were defects of the cement mantles (C1 and C2) in 90 hips. No femoral component had a stem and cement radiolucent line. Focal femoral osteolysis was seen in only two hips. One acetabular component was removed at 5 years because of late hematogenous infection. One acetabular component had asymptomatic migration. The remaining 96 acetabular components were well fixed. Focal acetabular osteolysis was present in four hips. The mean linear polyethylene wear rate was 0.06 (+/- 0.05) mm per year. In contrast to other reports of early failure and osteolysis, the use of a precoated femoral component in this study did not adversely affect the fixation of hybrid total hip arthroplasty, with definite failure of only 2% (two of 98) of the femoral components.