Clinical Results of the Wear Performance of Cross-Linked Polyethylene in Total Hip Arthroplasty : Prospective Randomized Trial

To investigate the clinical results of cross-linked polyethylene (CLPE) and to compare the CLPE wear against zirconia and stainless steel heads, we studied the radiographic wear after a minimum 3-year follow-up in total hip arthroplasty (THA). Ninety-four hips were randomly implanted with a 22.225-mm head cemented THA—the group of non-CLPE against zirconia and CLPE against 2 different zirconias and stainless steel. The linear wear rate was significantly lower in the group of CLPE against zirconia (0.067, 0.059 mm/y) and against stainless steel (0.068 mm/y) compared with non-CLPE against zirconia (0.170 mm/y). In the short-term results, the wear performance of CLPE against zirconia was superior to that of non-CLPE; however, it did not show a better wear rate than CLPE against stainless steel. Furthermore, long-term investigations will be necessary for understanding CLPE wear in vivo.     

Highly Cross-Linked Polyethylene in Total Hip Arthroplasty for Osteonecrosis of the Femoral Head : A Minimum 5-Year Follow-Up Study

We evaluated 162 hips with osteonecrosis of the femoral head that had undergone THA using highly cross-linked polyethylene liner after a minimum follow-up of 5 years. Neither femoral nor acetabular components displayed radiographic evidence of mechanical loosening or osteolysis, and no components had been revised at the latest follow-up. The mean rate of linear liner wear was 0.038 mm/year. Univariate regression analysis did not demonstrate that age, gender, weight, activity level or cup inclination had any influence on penetration. While the long term effects of altered mechanical properties of highly cross-linked PE remain unknown, the clinical and radiographic results at a minimum of 5 years are promising for this high-risk population.     

Characterization of Progression of Pelvic Osteolysis After Cementless Total Hip Arthroplasty : Computed Tomographic Study

A retrospective analysis of 63 primary total hip arthroplasty cases was done using repeated computed tomography scans to evaluate the pelvic osteolytic lesions in early stage. The progression rate of osteolysis of hips with small osteolytic volume less than 766.97 mm³ in initial CT was 85.82 mm³/year, and that of hips with osteolysis more than 766.97 mm³ was 456.3 mm³/year (P < 0.001). Younger patients less than 52 years old with good Harris Hip Scores (more than 80) frequently showed much faster progression in volume of osteolytic lesions. The rate of osteolysis was accelerated when the amount of osteolysis reached a certain threshold volume in active young patients in a cascade manner even in early stage.     

Primary Total Hip Arthroplasty With Duraloc Cup in Patients Younger Than 50 Years : A 5- to 7-Year Follow-Up Study

We evaluated the clinical and radiographic results of 67 (64 patients) cementless Duraloc-300 cups for young active patients after a mean follow-up period of 6.2 years. The preoperative mean Harris hip score improved from 46.24 to 96.5 points at 5 years. The survivorship of the cup, using radiographically confirmed aseptic loosening as the end point, was 100% at 5 years. The mean rate of liner wear was 0.125 mm/y (00-0.39 mm/y). Acetabular osteolysis was found in 14% (9 hips) of the 67 hips, and the osteolysis is related to polyethylene wear (P = .0024) and sex (P = .001). Although there was no aseptic loosening of the components, there was a high rate of liner wear of the polyethylene liner and acetabular osteolysis.     

Predicting Short-Term Outcome of Primary Total Hip Arthroplasty : A Prospective Multivariate Regression Analysis of 12 Independent Factors

The purpose of this study was to investigate factors affecting the short-term outcome of primary total hip arthroplasty (THA) and develop a multivariate regression equation to predict the short-term outcome of primary THA. Prospectively collected data for 101 primary THAs performed at a single institution were used in this study. Twelve independent variables were analyzed via correlation and multivariate regression analyses. Correlation analyses showed that three variables significantly influenced Western Ontario and McMaster Universities Osteoarthritis (WOMAC) physical function (PF) score at minimum follow-up of 1 year: preoperative WOMAC PF score (P < .0001), sex (GN, P = .0159), and the presence of preoperative comorbidities (CMB, P = .0246). Multivariate regression analysis yielded the following equation: Outcome = PF?0.45 − GN?9 + CMB?8 + 62, which can be used to predict the general short-term outcome of primary THA.     

Total Knee Arthroplasty with an Uncemented Trabecular Metal Tibial Component : A Registry-Based Analysis

Previous poor results have kept the appeal of uncemented total knee arthroplasties (TKAs) minimal. We analyzed the mid-term survivorship and reasons for failures of a contemporary uncemented porous tantalum monoblock tibial component nation-wide. During the study period (2003–2010), such tibial components were used in 1143 primary TKAs recorded in the Finnish Arthroplasty Registry. Seven-year survivorship of these TKAs was 100% (95% CI 99–100) with revision for aseptic loosening of the tibial component, and 97% (95% CI 96–98) with revision for any reason as the respective end points. The most common reasons for revisions were instability and prosthetic joint infections. In conclusion, TKAs using an uncemented porous tantalum monoblock tibial component showed excellent mid-term survivorship in a population-based setting.     

Total Knee Arthroplasty With 4.4 mm of Tibial Polyethylene : An Update

Three hundred eighty-seven one-piece, 8-mm tibial components were implanted in 313 patients. All tibial prostheses were manufactured with 4.4 mm of polyethylene. From this group, 116 patients underwent simultaneous bilateral total knee arthroplasty with an 8-mm tibial component on one side and a tibial component with at least 6.4 mm of polyethylene on the other side. Follow-up averaged 11.8 years. The average Knee Society knee score was 81, and the average pain score was 46. No polyethylene wear or osteolysis was identified radiographically. There were 7 knees with tibial radiolucencies, 5 knees with polyethylene failure of metal-backed patellae, and 1 tibial component failure. Survival rates for loosening or revision of any component for any reason were 98.9%, 97.5%, 95.1%, and 93.2% at 5-, 10-, 15-, and 18-years, respectively.     

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

Background

The 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.

Cementation of Cross-linked Polyethylene Liner Into Well-Fixed Acetabular Shells : Mean 6-Year Follow-Up Study

The purpose of this study was to evaluate retrospectively the outcomes of cementation of cross-linked polyethylene (PE) liner in a well-fixed metal shell in 23 hips with an average follow-up period of 6 years. The mean Harris hip score was 69.6 ± 12 (range, 46-83) points preoperatively. The average postoperative follow-up was 72.3 months (range, 56-100 months). At the final follow-up, the mean Harris hip score was 95.5 ± 3 (84-100) points. There was no change in the bone-shell interface. No new osteolytic lesions were identified. The lesions impacted with bone graft had united completely. The remaining osteolytic lesions had decreased in size. There was no recurrent osteolysis, hip dislocation, component migration, and failure at the cement-metal interface. The results of the current study revealed that cementation of cross-linked PE liner into a well-fixed shell provided good midterm durability.     

The Cementless Anatomic Benoist Girard (ABG) II Total Hip Arthroplasty : A Minimum 8-Year Follow-Up Study

We have evaluated 90 consecutive primary cementless ABG II total hip replacements. The bearings combined metal-on-polyethylene in 64 hips, and alumina-on-alumina in 26 hips. At the minimum 8-year follow-up, ten patients had died, seven had been lost to follow-up, two had undergone revision of either or both components, and 68 were still alive and had not been revised. With revision for any reason as the endpoint, the cumulative survival rate at 10 years was 97.5% ± 1.7%, and 98.7% ± 1.3% for the metal-back cup and the femoral component, respectively. No hip showed peri-acetabular osteolysis. The ABG II total hip arthroplasty has demonstrated favourable clinical and radiological outcomes as well as survival in the current series. Further follow-up is needed to confirm these mid-term results.     

Hip Resurfacing With the Biomet Hybrid ReCap-Magnum System : 7-Year Results

The purpose of this study was to report our clinical outcome of a large series of metal-on-metal hip resurfacing arthroplasty (HRA) using the hybrid Biomet ReCap-Magnum system. This is a single-designer surgeon series with an average of 5 ± 1 years. Seven hundred forty consecutive hybrid HRAs were performed in 653 patients. Kaplan-Meier survivorship with any revision as an end point was 96.4% at 7 years. Twenty-five (3.4%) cases were revised: 8 due to acetabular component loosening, 6 due to femoral neck facture, 4 due to failure of femoral component fixation, 2 due to deep infection, 2 due to adverse wear, 1 due to psoas tendonitis, 1 due to recurrent dislocation, and 1 due to unexplained pain. Biomet ReCap and Magnum HRA components with hybrid fixation methods showed excellent survivorship for a minimally selected young patient cohort at 7 years.     

National Trends in Primary Total Hip Arthroplasty in Extremely Young Patients : A Focus on Bearing Surface Usage

The purpose of this study was to present national trends in primary total hip arthroplasty (THA) and bearing surface usage for patients 30 years and younger. Using the Healthcare-Cost-and-Utilization-Project Nationwide Inpatient Sample for the years 2006 to 2009, 8919 primary THA discharges (4454 coded by bearing surface) were identified in patients 30 years and younger. The most commonly used bearing surface was metal-on-metal (MoM), representing 37.6% of cases, followed by ceramic-on-ceramic (CoC) (24.6%), metal-on-polyethylene (MoP) (22.1%) and ceramic-on-polyethylene (15.7%). From 2006 to 2009, the percentage of THAs that used hard-on-hard bearing surfaces decreased (MoM: 42.9%-29.4%; CoC: 34.0%-19.7%).This decrease in hard-on-hard bearing surface usage presents a challenge for surgeons treating young patients to find other acceptable durable bearings that do not have the potential problems associated with MoM or CoC.     

10-Year Follow-Up Wear Analysis of First-Generation Highly Crosslinked Polyethylene in Primary Total Hip Arthroplasty

Our goal was to report a 10-year follow up of linear penetration rates for HCLPE, and to determine whether a difference exists between penetrations measured on pelvis or hip anterior–posterior radiographs. We reviewed 48 total hip arthroplasties where a first-generation HCLPE liner was used. Femoral head penetration was measured on both AP pelvis and hip radiographs. Total wear and wear rate at 10 years were 1.26 mm and 0.122 mm/y, respectively. The rate decreased significantly after the first 2–3 years, plateauing at a wear rate of 0.05 mm/y for the last 5 years. The AP hip total wear and wear rate were 1.38 mm and 0.133 mm/y respectively, while rates were 1.13 mm and 0.109 mm/y respectively for the pelvis radiographs (P < .05). We found a significant difference in measurements of linear penetration when comparing AP pelvis vs. hip radiographs with lower rates recorded using an AP pelvis.     

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

Background

Short-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.

Wear Comparison Between a Highly Cross-Linked Polyethylene and Conventional Polyethylene Against a Zirconia Femoral Head : Minimum 5-Year Follow-Up

Highly cross-linked polyethylene (HXLPE) was developed to reduce wear of articular bearing surface in total hip arthroplasty patients. Several studies have shown reduced wear of HXLPE compared with conventional polyethylene; however, these studies had used HXLPE in combination with a Co-Cr metal head. The purpose of this study was to compare the 5-year in vivo wear of HXLPE with that of conventional PE using a zirconia femoral head. Forty-five hips with a Trilogy HXLPE (Zimmer, Warsaw, Ind) were matched and compared with a control group of 20 conventional Trilogy PE hips. The 2-dimensional linear wear rate was significantly less in the HXLPE group between 1 and 5 years postoperation (P < .001). The results show that HXLPE reduces short-term polyethylene wear against not only a Co-Cr head but also a zirconia head.     

Long-Term Outcome of Total Knee Arthroplasty in Charcot Joint : A 10- to 22-Year Follow-Up

The results of 11 total knee arthroplasties in 9 patients with a Charcot joint secondary to neurosyphilis were reviewed. The mean age was 60.1 years, and follow-up averaged 12.3 years. Endomodel rotating hinge prostheses (Waldemar Link GMBH and Co, Hamburg, Germany) were implanted in all knees. The mean knee score increased from 44.9 before surgery to 95.0 at the final follow-up, and the mean function score increased from 45.0 before surgery to 93.6 at the final follow-up. Complications were noted in 3 knees, including 2 dislocations of the knee and 1 deep infection. The clinical results of total knee arthroplasty were satisfactory in most cases of Charcot joint. Rotating hinge prostheses are strongly recommended for use in Charcot joint. However, the procedure is technically demanding, and there were considerable complications.     

Incidence of Osteolysis in Total Knee Arthroplasty : Comparison Between Radiographic and Retrieval Analysis

Detection of polyethylene wear and osteolysis in total knee arthroplasty using radiographs is imprecise. To correlate radiographic findings with retrieved tibial component analysis, we reviewed knee revision cases. A joint registry was used to identify all knee revisions. Radiographic scoring systems were developed. Radiographs were analyzed for osteolysis and implant alignment. Polyethylene liner retrievals were visually and optically graded for surface damage. Statistical analyses that included correlation analysis and Mann-Whitney U test were used. When osteolysis was found, radiographic scores and delamination score were significantly higher (P = .047 and P = .014, respectively). Delamination is a good indicator for polyethylene wear and osteolysis. There is a need to develop in vivo methods to identify polyethylene changes and thereby prevent severe clinical outcomes.     

Stable Fixation but Unpredictable Bone Remodelling Around the Lord Stem : Minimum 23-Year Follow-Up of 66 Total Hip Arthroplasties

Early designs of uncemented hip implants turned out to be failures mainly because the prerequisites for durable implant fixation were unknown. One exception was the chrome–cobalt stem of the Madreporic Lord prosthesis. We prospectively studied this prosthetic design in 107 hips that underwent surgery in 1979–1986. At the last follow-up, five stems and 54 cups had been revised, corresponding to stem and cup survival rates of 92% ± 3% and 45% ± 5% at 26 years. In all, 66 hips with remaining Lord stems were available for clinical follow-up 26 years (24–29) after the index operation. The mean total Harris hip and pain scores were 81 (SD 14) and 41 (SD 5).     

Unexpected Wear of a Uniquely Designed Moderately Cross-Linked Polyethylene in Total Hip Arthroplasty

BackgroundA uniquely designed, non–heat-treated moderately cross-linked acetabular polyethylene liner used in total hip arthroplasty (THA) demonstrated excessive wear during routine follow-up, prompting an evaluation of the linear wear rate.MethodsAll THAs were performed by the senior author. The study group included 38 THAs using the uniquely designed polyethylene in question, compared to a control group of 21 THAs using another moderately cross-linked polyethylene with good 10-year outcomes. Two-dimensional linear head penetration wear measurements were obtained using the Martell Hip Analysis Suite, and retrieval analysis was performed on two liners.ResultsThe study group had a significantly higher average penetration rate of 0.089 mm/y than the control group average rate of 0.047 mm/y (P = .04). Forty-five percent of the study group had a wear rate above the osteolysis threshold (0.1 mm/y), compared to 24% in the control group. Macroscopic analysis of two retrieved liners validated the radiographic findings.ConclusionThe data suggest unexpectedly higher wear rates for a moderately cross-linked polyethylene design, with nearly half of the study group at risk for osteolysis. Further registry or database analyses of this particular moderately cross-linked polyethylene are warranted.     

Medium-Term Follow-Up of a Modular Tapered Noncemented Titanium Stem in Revision Total Hip Arthroplasty : A Single-Surgeon Experience

We report a single-surgeon experience with a noncemented modular revision shaft (Modular Prosthesis; LINK, Hamburg, Germany) with clinical and radiographic results of 63 patients after 10 years. The Harris Hip Score improved from 51 to 84 points. Intraoperative complications included 11 fractures. Four patients had postoperative femoral fractures. Further shaft revisions were necessary: 1 subsidence, 1 late fracture, 1 late deep infection. Sixty-eight percent of cases showed revision defects as graded 3° by Mallory; 95 % did not show signs of loosening or subsidence; 38 patients showed adequate bone remodeling in the shaft and proximal femur; 21 patients showed excellent recovery of preoperative osteolytic areas, and 5 patients did not show signs of remodeling. The Modular Prosthesis stem shows adequate fixation and tendency toward satisfactory bone remodeling after 10 years.