Long-Term Follow-Up of Conventional Polyethylene in Total Hip Arthroplasty in Young Patients: Heightened Wear-Related Complications Are Observed at the Beginning of the Third Decade

BackgroundConventional polyethylene (CPE) was used widely in the past as a bearing surface in total hip arthroplasty (THA). As CPE THAs age and the revision burden continues to grow, it is increasingly important to understand the durability and failure mechanisms of this bearing material. Currently, such long-term data remain limited, particularly in younger, more active patients in whom wear issues are of greater concern.MethodsWe retrospectively reviewed 90 hips (77 patients) that underwent primary THA with CPE bearings on cobalt chrome femoral heads at age ≤50 years at 20-year minimum follow-up (mean 21.6 [20-23]). We analyzed polyethylene wear rates, clinical outcomes (modified Harris Hip Score, University of California, Los Angeles Activity Score), and implant survivorship.ResultsWear analysis revealed a median linear wear rate of 0.113 mm/y (95% CI 0.102-0.148) and a median volumetric wear rate of 41.20 mm³/y (95% CI 43.5-61.0). Modified Harris Hip Scores remained 37 points above preoperative baseline (P < .001) and University of California, Los Angeles scores 1.4 points above baseline (P = .018) at 21.6-year mean follow-up. Twenty-nine hips (32.2%) were revised, 20 of which (22.2%) were wear-related at a median of 15.4 years (interquartile range 11.4-19.5). Survivorship free from wear-related revision was 95.6% (95% CI 88.7-98.3), 87.9% (78.6-93.3), 78.1% (49.6-66.5), and 61.1% (41.3-67.0) at 10, 15, 20, and 25 years.ConclusionWear-related issues developed at increasingly high rates after 15 years, suggesting the need for surveillance after this time. The long-term wear and survivorship data of this study may be used as a benchmark when evaluating the performance of contemporary bearings in young, active THA patients.     

Modern total hip arthroplasty in patients younger than 21 years

Total hip arthroplasty (THA) is not commonly performed in adolescents. However, it may be the only option for pain control with continued mobility for advanced disease. We report our experience with modern alternative-bearing THA in patients younger than 21 years. Twenty-one THAs (18 patients) were followed. Preoperative and postoperative Harris hip scores were recorded, and radiographs were reviewed. Average follow-up was 49 months (range, 25-89). Underlying etiology was chemotherapy-induced osteonecrosis (33%), steroid-induced osteonecrosis (29%), sickle cell disease (24%), and chronic dislocation (14%). Articulation bearings were ceramic/ceramic (67%), metal/highly cross-linked polyethylene (29%), and metal resurfacing (5%). Mean age was 18 years (range, 13-20). Harris hip scores improved from 43.6 to 83.6 (P < .001). At final follow-up, there was no radiographic loosening; 1 THA was revised for a cracked ceramic liner. At intermediate-term follow-up, clinical and radiographic results are favorable after alternative-bearing THA in patients younger than 21 years.     

A Comparative Study of Four Bearing Couples of the Same Acetabular and Femoral Component: A Mean Follow-Up of 11.5 Years

We present a retrospective evaluation of 1369 hip arthroplasties performed using the Bicon-Plus cups and SL-Plus stems, differing only in the bearing combination. Four bearing combination groups were used: metal-on-polyethylene (MoP) group with 587 hips, ceramic-on-polyethylene (CoP) group with 161 hips, metal-on-metal (MoM) group with 322 hips and ceramic-on-ceramic (CoC) group with 299 hips. The mean follow-up was 11.5 years (4.1 to 15.0). Radiological evaluation was performed on implants failed due to aseptic loosening. The survival for prosthesis with revision for any reason at ten years was 96.1% (95% confidence interval (CI) 94.3 to 97.9) for MoP, 98.1% (CI 95.9 to 100) for CoP, 90.2% (CI 86.8 to 93.6) for MoM, and 95.6% (CI 93.0 to 98.2) for CoC. Survival for aseptic loosening was also determined.     

Short-term wear of Japanese highly cross-linked polyethylene in cementless THA

INTRODUCTION: Production of polyethylene wear from acetabular liners is thought, in part, to mediate the periprosthetic osteolysis. This study examined the in vivo wear performance of Japanese highly cross-linked polyethylene (Aeonian) in cementless total hip arthroplasty. MATHERIALS AND METHODS: Ninety-five hips received a highly cross-linked polyethylene liner, while 20 hips were implanted with conventional polyethylene. Two-dimensional linear wear was measured on radiographs and volumetric wear was then calculated. Both linear and volumetric wear rates were examined for the 1-year postoperative period as well as for the time frame beginning after 1 year ending with the final follow-up. RESULTS: The amount of linear wear was significantly lower in the cross-linked group at 3 and 5 years postoperatively (P < 0.01 and < 0.001, respectively). Linear and volumetric wear rates after 1 year postoperatively for hips with the cross-linked polyethylene were significantly reduced by 57 and 59%, respectively, when compared to rates for those who received conventional polyethylene (P < 0.01). A multiple logistic regression analysis revealed that cross-linking was a significant factor influencing linear wear rate after 1 year postoperatively with an odds ratio, exp(ss) = 10.033 (P < 0.001). CONCLUSION: These results suggest that the highly cross-linked polyethylene reduces penetration of the femoral head and may be an optimal bearing surface for patients receiving total hip arthroplasty.     

Wear analysis of first-generation highly cross-linked polyethylene in primary total hip arthroplasty: an average 9-year follow-up

This is a retrospective review of 46 primary total hip arthroplasties using a first-generation highly cross-linked ultrahigh-molecular-weight polyethylene liner (Crossfire; Stryker, Mahwah, NJ) with an average of 9-year follow-up. The purpose of this study was to measure linear penetration rate of first-generation polyethylene to determine if it maintains its wear resistance and fatigue strength over an extended period compared with conventional polyethylene. The mean (SD) total penetration was 0.339 (0.204) mm, and the mean (SD) penetration rate was 0.037 (0.022) mm/y. Our study demonstrated a 74% reduction in total penetration of highly cross-linked polyethylene when compared with historical controls using conventional polyethylene at an average of 9 years. Our results support the belief that highly cross-linked polyethylene does retain its wear resistance over an extended period.     

Biomechanical modeling of acetabular component polyethylene stresses,fracture risk,and wear rate following press‐fit implantation

Press‐fit implantation may result in acetabular component deformation between the ischial‐ilial columns (“pinching”). The biomechanical and clinical consequences of liner pinching due to press‐fit implantation have not been well studied. We compared the effects of pinching on the polyethylene fracture risk, potential wear rate, and stresses for two different thickness liners using computational methods. Line‐to‐line (“no pinch”) reaming and 2 mm underreaming press fit (“pinch”) conditions were examined for Trident cups with X3? polyethylene liner wall thicknesses of 5.9 mm (36E) and 3.8 mm (40E). Press‐fit cup deformations were measured from a foam block configuration. A hybrid material model, calibrated to experimentally determined stress–strain behavior of sequentially annealed polyethylene, was applied to the computational model. Molecular chain stretch did not exceed the fracture threshold in any cases. Nominal shell pinch of 0.28 mm was estimated to increase the volumetric wear rate by 70% for both cups and peak contact stresses by 140 and 170% for the 5.9 and 3.8 mm‐thick liners, respectively. Although pinching increases liner stresses, polyethylene fracture is highly unlikely, and the volumetric wear rates are likely to be low compared to conventional polyethylene. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1467–1472, 2009     

Dislocation following total hip replacement: the Avon Orthopaedic Centre experience

INTRODUCTION

The aim of this study was to determine the incidence and outcome of dislocation after total hip arthroplasty at our unit.

PATIENTS AND METHODS

In total, 1727 primary total joint arthroplasties and 305 revision total hip arthroplasties were performed between 1993 and 1996 at our unit. We followed up 1567 (91%) of the primary hip arthroplasties and 284 (93%) of the revision hip arthroplasties at 8–11 years after surgery. Patients were traced by postal questionnaire, telephone interview or examination of case notes of the deceased.

RESULTS

The dislocation rates by approach were 23 out of 555 (4.1%) for the posterior approach, 0 out of 120 (0%) for the Omega approach and 30 out of 892 (3.4%) for the modified Hardinge approach. Of dislocations after primary total hip arthroplasty, 58.5% were recurrent. The mean number of dislocations per patient was 2.81. Overall, 8.1% of revision total hip arthroplasties dislocated. 70% of these became recurrent. The mean number of dislocations per patient was 2.87. The vast majority of dislocations occurred within 2 months of surgery.

DISCUSSION

To our knowledge, this is the largest multisurgeon audit of dislocation after total hip arthroplasty published in the UK. The follow-up of 8–11 years is longer than most comparable studies. The results of this study can be used to inform patients as to the risk and outcome of dislocation, as well as to the risk of further dislocation.     

Influence of polyethylene creep behavior on wear in total hip arthroplasty.

After total hip arthroplasty (THA), polyethylene acetabular liner creep occurs quickly and serves to increases head-liner contact area and decrease contact pressures. What effect these early changes in contact mechanics will have on the wear behavior of the articulation remains unclear, and hence, selection or modification of polyethylene materials for optimal creep and wear performance is impossible. The objective of this study was to determine the influence of polyethylene creep behavior on volumetric wear and linear creep and wear penetration during simulated gait loading conditions. A finite element model of THA articulation was developed, and simultaneous numerical creep and wear simulation was performed to 10 million gait cycles with three levels of polyethylene creep behavior. Long-term volumetric wear and penetration were surprisingly unaffected by the polyethylene creep behavior due to the competing decrease in contact pressures coupled with increased contact area. In addition, variation in contact mechanics with the creep levels studied was only noteworthy in the initial postoperative period; after 1 million gait cycles, peak contact pressures and areas were within 13% regardless of the creep material behavior selected. Femoral head size had considerable impact on wear and penetration, while liner thickness primarily affected only early penetration. These results suggest that polyethylene creep behavior plays a major role in early penetration, but has little influence on the more important long-term volumetric wear.     

Five Year Results of the First US FDA-Approved Hip Resurfacing Device

A prospective, multi-center postmarket approval study has been ongoing since May 2006 to assess safety and efficacy of the first US FDA approved hip resurfacing implant. 265 patients have been enrolled at five study sites. The average age of the patients is 51.3 years. There have been 7 revisions (2.4%) in the cohort to date. K–M survival curves for the cohort are 97.6% at 5 years. There is a trend toward a gender difference in implant survivorship, with 98.6% of men and 94.7% of women free from revision. Metal ion analysis revealed median cobalt and chromium levels of 1.5 ppb and 1.7 ppb at 1 year. In this prospective US study, the Birmingham Hip Resurfacing implant is demonstrating results comparable to those in the literature.     

Periprosthetic Fractures of the Femur After Hip Arthroplasty: An Analysis of 99 Patients

The medical records and radiographs of 99 patients treated for a periprosthetic femur fracture after total hip arthroplasty over a 17-year period at a single institution were prospectively reviewed. Fractures were classified according to the Vancouver system and stratified as to treatment method. Sixty-six patients had complete records available and a minimum of 12 months follow-up. Overall, 86% of the patients achieved fracture union. The success rate of cemented revision in the B2 and B3 groups was 84%, whereas cement-less revision was 86% successful. The complication rate of surgical treatment was 29%. Fracture union with a stable implant was possible in the majority of cases. Our results support the use of the Vancouver classification as a treatment algorithm.     

In Vivo Performance of Vitamin E Stabilized Polyethylene Implants for Total Hip Arthroplasty: A Review

BackgroundVitamin E stabilization was introduced to improve the oxidative stability, wear resistance, and mechanical properties of highly crosslinked polyethylene (HXLPE). In this literature review, we asked: (1) How has vitamin E-stabilized HXLPE (VEPE) performed in vivo for total hip arthroplasty (THA) and how does it compare with conventional ultra-high molecular weight polyethylene (UHMWPE) and HXLPE without vitamin E; and (2) Is there an apparent difference in the clinical performance of VEPE created by blending versus diffusion?MethodsWe performed a systematic search of the literature according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines using PubMed and Embase. Included studies reported the in vivo behavior of VEPE in THA. We reviewed 41 studies.ResultsFor all studies that compared polyethylene with and without VE stabilization, outcomes for VEPE were either equivalent or superior to the control group (for HXLPE without VE and conventional UHMWPE controls, respectively). Hip insert wear rates were generally less than 0.1 mm/year and in most cases were less than 0.05 mm/year. No VEPE components were revised for osteolysis or adverse outcomes specific to VE incorporation.ConclusionAcross the literature, we found that VEPE was reported to be clinically effective for THA applications, with much of the research indicating positive clinical outcomes and lower or equivalent wear rates compared to conventional UHMWPE and HXLPE controls without VE. Instances of early component fracture were reported, but have multiple potential causes. There is a gap in the literature for comparison of blended and diffused components, so the in vivo impact of VE incorporation method remains to be seen. Overall, this study provides a comprehensive summary of VEPE clinical performance for THA and may serve as a resource for future investigations.     

A new cemented femoral stem: a prospective study of the Stryker accolade C with 2- to 5-year follow-up

This prospective study evaluates the short-term results of a recently released cemented femoral stem design in primary cemented and hybrid total hip arthroplasty (THA). There were 100 all-cemented and 100 hybrid THAs in the 2-year study group. Good to excellent results were obtained in 96%. There was one reoperation for recurrent dislocation in each cohort (1%) and one single-staged reoperation for sepsis in the cemented cohort. There were 47 THA available for 5-year follow-up. Good to excellent results were maintained in 98%. One additional patient had a revision because of late recurrent dislocation. This study has demonstrated excellent early results and safety with this cemented femoral stem. The features include a dual-wedge geometry with a 0.88-microm Ra surface roughness, proximal macro-normalizations, distal anti-rotation grooves, and an optimized head-and-neck ratio approaching 4:1 using a standard 28-mm head.     

The Outcomes Following Revision of Monoblock Metal on Metal Acetabular Components for Painful Micromotion in the Absence of Adverse Local Tissue Reaction to Metal

Background

Revision hip arthroplasty for metal-on-metal arthroplasty (MOMA) in the presence of an adverse local tissue reaction (ALTR) has been associated with compromised outcomes. We hypothesized that revision of MOMA for painful micromotion of the cup, in the absence of ALTR, would have a more favorable outcome.

Surgical treatment of Sprengel's shoulder: experience at the Rizzoli Orthopaedic Institute 1975-2010

The outcome of 56 children (61 shoulders) treated surgically at the Rizzoli Institute between April 1975 and June 2010 for congenital elevation of the scapula is reported. There were 31?girls and 25 boys with a mean age at surgery of 6.4 years (2 to 15). The deformity involved the right shoulder in 20 cases, the left in 31 and was bilateral in five. The degree of the deformity was graded clinically and radiologically according to the classifications of Cavendish and Rigault, respectively. All patients underwent a modified Green procedure combined, in selected cases, with resection of the superomedial portion of the scapula and excision of any omovertebral connection. After a mean follow-up of 10.9 years (1 to 29.3), there was cosmetic improvement by at least one Cavendish grade in 54 shoulders (88.5%). The mean abduction of the shoulder improved from 92° (50° to 155°) to 112° (90° to 170°) and the mean flexion improved from 121° (80° to 160°) to 155° (120° to 175°). The unsatisfactory cosmetic result in seven shoulders was due to coexistent scoliosis in two cases and insufficient reduction of the scapular elevation in the other five. An incomplete upper brachial plexus palsy occurred post-operatively in three patients but resolved within seven months. We suggest that a modified Green procedure combined with resection of the superomedial portion of the scapula provides good cosmetic and functional results in patients with Sprengel's shoulder.