Revision total hip arthroplasty for metal-on-metal failure

Metal-on-metal (MoM) arthroplasty systems became popular in the early-2000s due to presumed advantages of improved wear characteristics and superior stability. However, subsequent reports of abnormal soft-tissue reactions to MoM implants and national registry data reporting high failure rates raised concerns. Early outcomes of revision total hip arthroplasty (THA) for adverse reaction to metal debris (ARMD) were poor, leading to development of surveillance programs and a trend towards early revision surgery. Patients with MoM arthroplasties require surveillance, comprehensive history and physical examination, imaging with ultrasound or magnetic resonance imaging (MRI), and laboratory evaluation including metal ion levels. Operative strategies for revision THA vary from exchange of modular components to extensive debridement and reconstruction with revision components. Surgeons should be aware of the increased risks of dislocation and infection following revision THA for ARMD. However, there is growing evidence that early revision surgery prior to extensive soft tissue destruction results in improved outcomes and decreased re-operation rates. It is estimated that >1 million MoM articulations have been implanted, with a large proportion still in situ. It is imperative to understand the aetiology, presentation, and management strategies for these patients to optimise their clinical outcomes.     

Effects of cobalt and chromium ions at clinically equivalent concentrations after metal-on-metal hip replacement on human osteoblasts and osteoclasts: implications for skeletal health

Metal-on-metal hip replacement (MOMHR) using large diameter bearings has become a popular alternative to conventional total hip arthroplasty, but is associated with elevated local tissue and circulating levels of chromium (Cr) and cobalt (Co) ions that may affect bone health. We examined the effects of acute and chronic exposure to these metals on human osteoblast and osteoclast formation and function over a clinically relevant concentration range previously reported in serum and within hip synovial fluid in patients after MOMHR. SaOS-2 cells were cultured with Co²⁺, Cr³⁺ and Cr⁶⁺ for 3 days after which an MTS assay was used to assess cell viability, for 13 days after which alkaline phosphatase and cell viability were assessed and for 21 days after which nodule formation was assessed. Monocytes were isolated from human peripheral blood and settled onto dentine disks then cultured with M-CSF and RANKL plus either Co²⁺, Cr³⁺ or Cr⁶⁺ ions for 21 days from day 0 or between days 14 and 21. Cells were fixed and stained for TRAP and osteoclast number and amount of resorption per dentine disk determined. Co²⁺ and Cr³⁺ did not affect osteoblast survival or function over the clinically equivalent concentration range, whilst Cr⁶⁺ reduced osteoblast survival and function at concentrations within the clinically equivalent serum range after MOMHR (IC₅₀ = 2.2 μM). In contrast, osteoclasts were more sensitive to metal ions exposure. At serum levels a mild stimulatory effect on resorption in forming osteoclasts was found for Co²⁺ and Cr³⁺, whilst at higher serum and synovial equivalent concentrations, and with Cr⁶⁺, a reduction in cell number and resorption was observed. Co²⁺ and Cr⁶⁺ within the clinical range reduced cell number and resorption in mature osteoclasts. Our data suggest that metal ions at equivalent concentrations to those found in MOMHR affect bone cell health and may contribute to the observed bone-related complications of these prostheses.     

Complications after metal-on-metal hip resurfacing arthroplasty

This article determines the incidence and cause of the complications commonly associated with metal-on-metal hip resurfacing implants and the proposed methods to prevent these complications. The literature available in PubMed was reviewed. Complication rates after hip resurfacing are low, and the procedure has shown both safety and efficacy in the hands of surgeons trained in specialized centers. Proper surgical technique can further reduce the incidence of femoral neck fracture, component loosening, and abnormal wear of the prosthesis. A more systematic detection of adverse local tissue reactions is needed to provide accurate assessments of their prevalence.     

Outcomes of a metal-on-metal total hip replacement system

Introduction

High short-term failure rates have been reported for a variety of metal-on-metal (MoM) total hip replacements (THRs) owing to adverse reactions to metal debris (ARMD). This has led to the withdrawal of certain poorly performing THRs. This study analysed the outcomes of a MoM THR system.

Methods

Between 2004 and 2010, 578 uncemented MoM THRs (511 patients, mean age: 60.0 years) were implanted at one specialist centre. The THR system used consisted of the Corail^® stem, Pinnacle^® cup, Ultamet^® liner and Articul/eze^® femoral head (all DePuy, Leeds, UK). All patients were recalled for clinical review with imaging performed as necessary.

Results

The mean follow-up duration was 5.0 years (range: 1.0–9.1 years). Overall, 39 hips (6.7%) in 38 patients (all 36mm femoral head size) underwent revision at a mean time of 3.5 years (range: 0.01–8.3 years) from the index THR with 30 revisions (77%) performed in women. The cumulative eight-year survival rate for all THRs was 88.9% (95% confidence interval [CI]: 78.5–93.4%), with no difference (p=0.053) between male (95.2%, 95% CI: 84.2–98.7%) and female patients (85.3%, 95% CI: 70.2–92.1%) at eight years. Seventeen revisions (44%) were performed for ARMD. There was no significant difference in absolute postoperative Oxford hip scores between men and women (p=0.608). The mean acetabular inclination in unrevised THRs was 44.0°. Forty-seven non-revised THRs (8.7%) had blood metal ion concentrations above recommended thresholds (seven had periprosthetic effusions).

Conclusions

Although this MoM THR system has not failed as dramatically as other similar designs, we recommend against continued use and advise regular clinical surveillance to identify ARMD early.     

Revisions of metal-on-metal hip resurfacing: lessons learned and improved outcome

This retrospective, consecutive case series of a single surgeon performed between 2001 and 2010 assesses the outcome following revision of metal-on-metal hip resurfacing arthroplasties (N = 113). Mean time to revision was 31 months (0-101) after primary hip resurfacing. Malpositioning of the components with associated wear-induced soft tissue fluid collections was the most frequent factor leading to failure of a hip resurfacing arthroplasty. The mid-term outcome of the revisions was satisfactory; complications occurred in 11 patients (9.7%). Six of these patients underwent a re-revision.     

Femoral revision in hip resurfacing compared with large-bearing metal-on-metal hip arthroplasty

It has been suggested that revision of the femoral component of hip resurfacing after femoral failure would be straightforward and have an outcome comparable to primary total hip arthroplasty (THA). We have compared the outcome of femoral side-only revision resurfacings to the results of primary modular large-bearing metal-on-metal THA. Fourteen consecutive patients underwent revision surgery of the failed femoral component, to a cemented tapered stem (CPT, Zimmer, Warsaw, Indiana) with a large modular metal head (Smith and Nephew Orthopaedics Ltd, Memphis, Tennessee, or Adept, Finsbury Orthopaedics, Surrey, England). The acetabular component was found to be well fixed, well orientated, and was left in situ. The 14 matched patients in the primary THA group received the same components. At a mean follow-up of 49 months (range, 30-60 months), clinical outcome measured using the Oxford and Harris Hip Scores showed no significant difference (P = .11, P = .45, respectively). Operative time and blood loss were comparable for both groups. We conclude that revision of the failed femoral resurfacing component gives excellent results.     

金属对金属全髋关节表面置换术早中期临床报告

目的探讨金属对金属全髋关节表面置换术治疗髋关节疾病的早中期临床效果,分析影响疗效的相关因素。方法回顾性分析我科全髋关节表面置换术患者54例60髋,男28例32髋,女26例28髋,年龄22～62岁,平均（42.3±12.5）岁。术后患者均进行定期临床与影像学随访16～45个月,平均随访32个月。采用Harris,UCLA,VAS评分对患者术前术后的髋关节功能进行评估。结果 Harris评分由术前38.3分增加到术后95.4分;UCLA评分由术前3.6分增加到术后7.9分;VAS评分由术前8.8分降低到术后1.8分。患者假体位置良好,无假体松动、关节脱位、股骨颈骨折及明显骨溶解等并发症。结论全髋关节表面置换术能有效改善髋关节疾病患者的关节功能、减轻疼痛,早中期随访结果满意。     

Metal-on-metal total hip replacement: Monitoring and intervention strategies

Metal-on-metal total hip arthroplasty was once a very common articulation in performing hip replacement surgery. Although over time there has been a decline in use, surgeons must be able to follow these patients and intervene when appropriate. We review an approach to monitoring metal-on-metal total hip arthroplasties. We also review intervention strategies and an algorithm to follow such patients.     

Hip resurfacing: mid-term results of the last-generation metal-on-metal devices

Total hip resurfacing has long been conceptually attractive to both surgeons and patients. However, historically it has been plagued by limited durability and marked acetabular bone loss. The recent development of wear-resistant bearings such as metal-on-metal has led to renewed interest in hip resurfacing in the orthopaedic community. We report the clinical and radiological results of 350 consecutive surface arthroplasties performed in 325 patients (mean follow-up 20 months). Harris Hip Score increased over time from 57 pre-operatively to 98 at 2 years follow-up. Complication’s rate was low. Four patients required revision surgery. The overall survival rate was 98.8%. Considering the positive results of more than 350 implants of our series, we now believe that there is evidence showing that this surgical concept deserves consideration, particularly when treating young patients with hip diseases.     

Second generation of metal-on-metal cemented total hip replacements: 12 years of clinical and biological follow-up

The second generation of metal-on-metal prostheses appeared at the end of the 1980’s as a serious alternative to metal on polyethylene bearing couples. Short-term clinical results were promising; however certain questions remain concerning clinical, radiological and biological aspects. Release of chromium and cobalt from the bearing couple is one of these aspects. The aim of this study is to analyse the results of a series of 97 cemented total hip prostheses comprising a titanium femoral stem and the Metasul® metal-metal bearing couple. Mean follow-up was nine years (7–12 years). Complications were marked by 12 revisions, out of which two were for recurrent early dislocations, eight for clinical and radiological failure, and two for worrying radiological alterations. During these revisions, we observed a serious infiltration of metal debris four times, leading to an alternative strategy using an alumina-alumina bearing couple. Three more revisions are planned for rapidly evolving radiological alterations. Thirty implants showed radiological signs of preoccupying deterioration on the acetabular side. Eight segmentary femoral osteolysis have been observed. Twelve patients suffer from recurrent subluxation. Concerning the global evolution of metal serum levels, cobalt remains stable after five years. The values are three to four times above those of a non-exposed subject, but largely below toxic ratios. The evolution of serum chromium levels is similar to cobalt. Implantation of two prostheses in one same patient leads to significant increase in serum metal ratios. This series raises questions concerning the reliability of the metal-on-metal bearing couple. Osteolysis is an unsolved problem. Today, cemented fixation is debatable although this series doesn’t allow this parameter to be held directly responsible. Nothing points to any shortcomings concerning the taper fixation or the metallurgy of the femoral stem. The study of the serum metal levels seems a good indicator of the impingement situations and the functioning of the bearing couple.     

Management of failed metal-on-metal total hip arthroplasty

The theoretical advantages of metal-on-metal (MOM) bearing couples in total hip arthroplasty (THA) have been recently balanced by concerns regarding adverse local and systemic effects. Higher than anticipated early revision rates have been reported by several joint registries. Failed MOM hips present with a spectrum of symptoms and findings and traditional methods of failure must be considered in addition to the failure modes that appear to be unique to the MOM bearing couple. Metal hypersensitivity and soft tissue immune reactions remain incompletely understood and require careful ongoing study. The tools available to evaluate MOM THAs and the indications for revision surgery remain to be defined. Outcomes following revision of MOM hips appear to depend on appropriate evaluation, early identification, and appropriate surgical management.     

Chinese experience with metal-on-metal hip resurfacing

The aim of this study was to study the actual clinical and laboratory results of metal-on-metal resurfacing hip arthroplasties by comparing with other implants. A total of 127 cases were operated on at the Department of Orthopaedics of Wuhan Union Hospital from 2005 to 2011. An important cause of failure is the fracture of the femoral neck. The chromium and cobalt levels of resurfacing hip arthroplasty and large-diameter head total hip arthroplasty (THA) are higher than those of a conventional metal-on-polyethylene total hip arthroplasty. There was a high ion level associated with an abduction angle of more than 45° and repetitive extreme hip motion in the 3 revision cases. The findings of this study are novel and quite controversial with that of the previously published literature.     

Identification and treatment of anaemia in patients awaiting hip replacement

INTRODUCTION

The correction of anaemia prior to total hip arthroplasty reduces surgical risk, hospital stay and cost. This study considers the benefits of implementing a protocol of identifying and treating pre-operative anaemia whilst the patient is on the waiting list for surgery.

PATIENTS AND METHODS

From a prospective series of 322 patients undergoing elective total hip arthroplasty (THA), patients identified as anaemic (haemoglobin (Hb) < 12 g/dl) when initially placed upon the waiting list were appropriately investigated and treated. Pre- and postoperative Hb levels, need for transfusion, and length of hospital stay were collated for the entire patient cohort.

RESULTS

Of the cohort, 8.8% of patients were anaemic when initially placed upon the waiting list for THA and had a higher transfusion rate (23% versus 3%; P < 0.05) and longer hospital stay (7.5 days versus 6.6 days; P < 0.05). Over 40% of these patients responded to investigation and treatment whilst on the waiting list, showing a significant improvement in Hb level (10.1 g/dl to 12.7 g/dl) and improved transfusion rate.

CONCLUSIONS

Quantifying the haemoglobin level of patients when initially placed on the waiting list helps highlight those at risk of requiring a postoperative blood transfusion. Further, the early identification of anaemia allows for the utilisation of the waiting-list time to investigate and treat these patients. For patients who respond to treatment, there is a significant reduction in the need for blood transfusion with its inherent hazards.     

Deep vein thrombosis after total hip arthroplasty in Korean patients and D-dimer as a screening tool

Introduction  This prospective study was designed to confirm risk factors and to assess the incidence of deep vein thrombosis after total hip and surface replacement arthroplasty in Korean patients not receiving anticoagulation prophylaxis and to determine efficacy of plasma D-dimer levels as a screening test. Materials and methods  From May 2003 to August 2004, 221 consecutive patients undergoing unilateral total hip arthroplasty and hip resurfacing were evaluated. All patients underwent ultrasonography preoperatively and venography and/or ultrasonography on postoperative day 7. Plasma D-dimer levels were estimated by latex immuno-assay preoperatively and on days 3 and 7 postoperatively. Results  Of the 221 patients in our cohort, 23 developed deep vein thrombosis (10.4%). Age (r = 0.245, P < 0.001) and gender (r = 0.155, P = 0.021) significantly correlated with deep vein thrombosis. Rise in incidence paralleled increase in age (X² = 32.860, P < 0.001). D-dimer levels on postoperative days 3 (γ = 0.364, P < 0.001) and 7 (γ = 0.470, P < 0.001) were significantly correlated to the development of DVT. Conclusion  While incidence of deep vein thrombosis in Korean population after THA was lower than that in the West; it increased with age, and in female gender. Significant correlation was found between D-dimer levels and the development of deep vein thrombosis.     

Failure modes of 433 metal-on-metal hip implants: how, why, and wear

Metal-on-metal total hip replacements (THRs) and hip resurfacings are coming under increasing scrutiny in light of concerns that they fail because of high wear and elevated metal ions. The aim of this study was to investigate the modes of failure in a collection of 433 metal-on-metal THRs and hip resurfacings and to examine the correlations between the reasons for revision and a range of patient and implant variables considered relevant to implant wear.     

金属对金属大直径股骨头全髋关节置换术的近期疗效观察

目的探讨金属对金属大直径股骨头全髋关节置换术（total hip replacement,THR）的近期疗效。方法回顾性分析2006年3月至2008年8月行金属对金属大直径股骨头THR16例19髋,男10例12髋,女6例7髋;年龄30～69岁,平均46岁;左侧7髋,右侧12髋;股骨头坏死5例6髋,强直性脊柱炎髋关节病变3例4髋。股骨颈骨折4例4髋,类风湿关节炎2例3髋,髋臼发育不良继发骨关节炎2例2髋。手术均采用后外侧入路,切口长9—13cm,平均11．7cm;髋臼假体全部用小厚度的金属臼杯,金属股骨头假体直径48—56mm。结果16例患者随访时间6．3～10．9个月,平均8．7个月。术中无一例出现骨折、神经麻痹、血管损伤等并发症,术后亦未发生脱位、假体松动及深静脉血栓等并发症,所有患者下肢长度的差异〈5mm。Harris评分由术前的32—55分,平均（43．6±6．8）分提高至术后随访时的76～96分,平均（90．7±11．9）分;髋关节活动度（rangeofmotion,ROM）中屈曲由术前平均87．5°±11．7°提高至术后平均109．8°±19．2°,外展由术前平均22．7°±3．4°提高至术后平均39．7°±4．9°,内收由术前平均13．2°±1．9°提高至术后平均23．5°±3．7°,内旋由术前平均2．1°±0．7°提高至术后平均21．4°±3．2°,外旋由术前平均27．6°±4．1°提高至术后平均54．3°±8．6°。结论采用金属对金属大直径股骨头THR治疗股骨头坏死、强直性脊柱炎导致的髋关节炎、类风湿关节炎和髋臼发育不良的年轻或较大活动量的患者近期疗效良好。     

Imaging of metal-on-metal hip resurfacing

Conventional radiography is the primary imaging modality to evaluate the condition of hip resurfacing implants and the preferred method of assessing implant stability over time. Radiographs assess the angle of inclination of the femoral and acetabular components, implant stability, and femoral neck narrowing. Ultrasonography detects solid or soft tissue masses adjacent to the implant. Magnetic resonance imaging (MRI) detects osteolysis and complications in the periprosthetic soft tissues such as wear-induced synovitis, periprosthetic collections, neurovascular compression, and quality of the muscle and tendons of the rotator cuff of the hip. For pain after hip resurfacing, early use of optimized MRI is recommended.     

Comparison of fully porous-coated and hybrid hip resurfacing: a minimum 2-year follow-up study

The purpose of this study was to compare clinical and radiological outcomes of the first 191 fully porous-coated hip resurfacing arthroplasties with 96 hybrid hip resurfacing arthroplasties performed during the same period at a minimum 2-year follow-up to evaluate the initial fixation of uncemented femoral resurfacing components. The results of this study indicate that fully porous-coated femoral resurfacing components can routinely achieve reliable fixation and provide similar initial results as have been achieved with cemented fixation. Long-term results are needed to determine which type of fixation is superior for the femoral hip resurfacing component.     

金属对金属髋关节表面置换术治疗强直性脊柱炎的临床研究

目的探讨金属对金属(MOM)髋关节表面置换术治疗强直性脊柱炎(AS)的早期临床疗效。方法对18例AS累及髋关节患者(23髋)行MOM髋关节表面置换术,术后定期随访,比较手术前后Harris评分、UCLA活动评分和影像学变化。结果术后平均随访20个月(6～36个月),Harris评分由术前(44±7)分上升到术后(89±6)分,UCLA活动评分由术前(2.4±1.15)分上升到术后(6.5±0.5)分,无感染、关节脱位、深静脉血栓形成、神经损伤和假体周围骨折等并发症的发生,术后X线检查假体无松动和移位。结论 MOM髋关节表面置换术治疗AS能够明显缓解患者症状,改善关节功能。