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.     

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.     

Five-year results of metal-on-metal resurfacing arthroplasty in Asian patients

Clinical results of 50 metal-on-metal resurfacing arthroplasties in 45 Japanese patients were evaluated to a minimum follow-up of 5 years. The predominant diagnosis was developmental dysplasia or dislocation of the hip (70%). One patient died of an unrelated cause and another was lost to follow-up. Two hips received revision surgery, including 1 femoral neck fracture and 1 septic loosening. In the remaining 46 hips, 1 hip showed femoral component loosening. Clinical scores of the 46 hips were satisfactory at the final follow-up. The survival rate at 5 years was 96% when failure was attributed to revision for any reason. Metal-on-metal resurfacing arthroplasty in Japanese patients, who have a different distribution of hip diseases from European and American patients, showed similarly promising early clinical results.     

Early complications of hip resurfacing

There has been a rapid increase in the number of hip resurfacing procedures for the treatment of symptomatic osteoarthritis over the last decade. We examine our early complications associated with this procedure. Eight hundred forty consecutive hip resurfacing procedures by 1 surgeon using 1 prosthesis were assessed. The complications seen within the first 12-month postoperative period were analyzed. Specific patient selection criteria were used. Complications such as loosening, femoral neck notching, femoral neck fracture, deep vein thrombosis, stress fracture, nerve palsy, and infection were noted. Complications linked with loosening were categorized to either the femoral or acetabular component. A total of 86 early complications were observed in the 840 resurfacings. Twenty-three (2.7%) required operative intervention, and 10 (1.2%) were converted to stemmed hip arthroplasties. Of these 86 complications, the most common complication was deep vein thrombosis, 19 instances (2.26% occurrence in 840), followed by femoral neck fracture, 11 (1.31%); infection, 10 (1.19%); femoral notching, 10 (1.19%); transient nerve palsy, 8 (0.95%); acetabular loosening, 6 (0.71%); hematoma, 5 (0.60%); and stress fracture, 4 (0.48%). The fractures occurred mostly in patients older than 60 years.     

Lack of radiographic loosening signs in a hip resurfacing that failed by stem fracture

Fracture of the femoral stem is a rare manifestation of femoral component loosening in hip resurfacing. The patient had undergone successful hip resurfacing 3 years prior to presentation, presenting with complaints of groin pain, but without radiographic evidence of loosening. At 6 years post-operatively, the patient again presented with groin pain. Radiographs demonstrated a mid-stem fracture. Analysis of the retrieved implant and resected femoral head following conversion to total hip arthroplasty indicated that component failure and fracture appeared to be secondary to failed fixation and implant loosening not related to osteonecrosis or acute femoral neck fracture. The case report highlights the difficulty in diagnosing femoral component loosening in hip resurfacing in the absence of gross implant subsidence or stem radiolucency.     

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.     

Clinical correlation of femoral component migration in hip resurfacing arthroplasty analyzed by Einzel-Bild-Röntgen-analyze-femoral component analysis

Hip resurfacing arthroplasty using metal-on-metal bearings has become increasingly popular. Wear of these bearings has been imperceptible on plain radiographs. Migration analysis studies may represent the opportunity to detect early failures and evaluate long-term prosthetic survival. The authors retrospectively reviewed 29 hips in a consecutive series of metal-on-metal hip resurfacing arthroplasties with a long-term clinical follow-up (average 8.7 years) to analyze the femoral component migration pattern by means of Einzel-Bild-R?ntgen-Analyze-femoral component analysis (EBRA-FCA). Femoral component migrations at 2 years and latest follow-up were compared with the known clinical outcomes. The authors' findings add validity to EBRA-FCA as a means to monitor femoral component migration and the clinical outcome of metal-on-metal hip resurfacing arthroplasty.     

Metal-on-metal hip resurfacing radiographic evaluation techniques

Hip resurfacing devices require a new radiographic evaluation technique owing to femoral components with short or no stems. Fourteen US surgeons implanted 1148 metal-on-metal hip resurfacing (HR) devices in a US-FDA-IDE clinical trial, which began in 2001. In this multi-center, prospective study, 337 patients (mean age, 50.1 years) were enrolled as a study group of unilateral HR arthroplasties. Radiographs of 292 HR arthroplasties at a minimum 2-year follow-up (maximum 3 years) were reviewed. There were 10 patients with radiographic evidence of femoral component instability beyond 2 years, as evidenced by subsidence > or = 5mm. Of these, 7 did not have clinical symptoms associated with femoral component instability. In the study group, 24 revisions were reported, of which 8 were due to femoral neck fractures, 4 were due to acetabular component loosening, 11 were due to femoral component loosening, and 1 due to dislocation.     

Der Oberflächenersatz am Hüftgelenk

Resurfacing arthroplasty is regarded as an attractive method, especially for the young patient who needs a hip replacement. However, the high expectations regarding this new technique in THR must first be met. Earlier experiences with similar forms of surface replacement have led to high revision rates with early aseptic wear induced component loosening and neck fractures. Technical progresses in production techniques for metal-on-metal articulations with minimized wear have enabled the introduction of new surface replacements for the hip joint. Long-term results of these resurfacing arthroplasties are still due. Femoral neck fractures and femoro-acetabular impingement are possible early complications which require revision. The implantation of these systems requires a high degree of operative skill and experience on the part of the surgeon. Approach dependent trauma to the musculature and endangering of the blood supply to the femoral head is balanced with the positive effect of the preservation of femoral bone stock and better options in case of revision. Whether the younger patient with a higher activity profile and an increased chance of implant loosening actually profits from the resurfacing arthroplasty will be determined in the future.     

Dislocating medial head of triceps--awareness of the condition could avoid inappropriate surgery--a case report

Background Modern metal-on-metal hip resurfacing implants are being increasingly used for young and active patients, although the long-term outcome and failure mechanisms of these implants are still unknown. In this consecutive revision case series, early failures of femoral implants (at < 4 years) were studied.

Methods 3 revisions were done due to a fracture of the femoral neck and 1 due to loosening and varus position of the femoral component. Femoral heads were removed en bloc 2–46 months after the primary operation, embedded in methylmethacrylate, sectioned, stained, and analyzed as whole-mount specimens in 4 55–62-year-old patients with osteoarthritis.

Results Histopathology was characterized by new but also partly healed trabecular microfractures, bone demineralization, cysts, metallosis, and abnormal formation of new woven bone. All samples displayed signs of notching, osteoporosis, and aseptic necrosis, which seemed to have been the main reason for the subsequent development and symptoms of the patients and revision operations of the hips.

Interpretation Based on these early revision cases, it appears that aseptic necrosis is a common cause of early loosening of resurfacing hip implants.     

Hydroxyapatite-coated femoral implant in metal-on-metal resurfacing hip arthroplasty: minimum of two years follow-up

The authors report preliminary results of an uncemented, hydroxyapatite-coated femoral implant for metal-on-metal hip resurfacing. The survival rate of 70 implants after at least 2 years follow-up was 98.6%, with an excellent clinical outcome. There have been no femoral fractures, aseptic loosening, or radiolucencies around the stem. Thinning of the femoral neck at the inferomedial cup-neck rim has been a frequent radiologic finding but with no clinical implication so far. Longer follow-up is needed to confirm the results.     

髋关节表面置换术后不同股骨假体位置的生物力学实验研究

目的探讨金属对金属(MOM)髋关节表面置换术后不同的假体位置对股骨近端生物力学性能的影响。方法随机选择地区、种族、性别相同的青壮年福尔马林浸泡1年内的防腐股骨标本24个,X线摄片排除骨折、肿瘤、结核及先天畸形,随机分为3组,即中立位组、内偏组、外偏组,建立静止单腿站立位股骨头受力模型,MTS生物力学测试机测试800N载荷下标本在髋关节表面置换前后股骨近段的载荷-应变关系、垂直位移和刚度。结果不同的实验组,在正常生理载荷下的载荷-应变关系都基本呈线性变化;在载荷为800N时,未置换组和不同实验组的表面置换术后的股骨平均应变、最大平均位移、刚度等指标的测试结果,经统计学处理均有统计学差异(P0.05)。结论中立位组的表面置换术后的股骨颈及近端股骨的应力传递较内偏组及外偏组更接近生理状态,未发现股骨颈及股骨近端的应力遮挡。因此,本研究认为中立位组的表面置换较内偏位及外偏位的假体位置更优,在表面置换术中应尽量避免股骨侧假体的内外侧移位。     

Charnley total hip arthroplasty with use of improved cementing techniques: a minimum twenty-year follow-up study.

BACKGROUND: In total hip arthroplasty, techniques for cementing the femoral component have changed over time. The purpose of the present study was to determine whether a cementing technique that includes use of a distal cement plug and retrograde filling of the femoral canal affects the fixation of the femoral component at a minimum of twenty years after the operation. METHODS: Between 1976 and 1978, the senior one of us (R.C.J.) performed 357 total hip arthroplasties with use of a Charnley flatback polished femoral stem and a contemporary cementing technique (insertion of a distal cement plug and retrograde filling of the femoral canal with cement) in 320 patients. The results after a minimum follow-up of twenty years were compared with those after 330 total hip arthroplasties performed, between 1970 and 1972, with the same femoral stem by the same surgeon with use of a hand-packing technique of cementing in 262 patients. The clinical and radiographic evaluation as well as the duration of follow-up were identical in the two groups. RESULTS: In the group managed with the contemporary cementing technique, six (1.8%) of the 336 hips that had not been lost to follow-up or revised because of infection or dislocation were revised because of aseptic loosening of the femoral component. Of the ninety-one hips in the eighty-two patients who were alive at a minimum of twenty years, five (5%) had a revision because of aseptic loosening of the femoral component. Only one hip was revised during the fifteen-to-twenty-year follow-up interval. (The revision was performed because of a fracture of the femoral component.) The rate of failure when radiographic signs of loosening were included was 4.8% (sixteen of 336 femoral components that had not been revised because of infection or dislocation) for the group managed with the contemporary cementing technique compared with 6.3% (twenty of 319 hips) in the group managed with the hand-packing technique; the difference was not significant (p = 0.40). Adequate filling of the femoral canal with cement was found to be associated with improved survival of the femoral component (p = 0.03). CONCLUSIONS: While no significant difference between the two cementing techniques could be identified, the ability to deliver adequate cement around the femoral component was more predictable with the contemporary cementing technique. In addition, the prevalence of loosening of the femoral component was low with use of either technique, a tribute to the Charnley flatback polished femoral component design.     

Biomechanische Aspekte zur Implantatverankerung und Kinematik von Oberflächenersatzhüftendoprothesen

Hip resurfacing is undergoing a resurgence in orthopaedic surgery with an increasing number of implantations. The objective of this article is to present the biomechanical basics of implant anchorage as well as the kinematics of hip resurfacing implants.Today, fixation of the femoral component onto the prepared femoral head is mainly done using bone cement. Depending on the implant design, the bone structures beneath the femoral component can be exposed to stress shielding, followed by degradation of the bone density and subsequent initiation of implant loosening. However, the trabecular bone has the ability to adapt itself to the fixation peg, to additional cement pegs, and to the elastic properties of the femoral component as well.The acetabular component is mainly inserted into the bone stock without using cement. Provided that large prosthetic heads will be applied, thin-walled acetabular cups are crucial for bone-saving preparation of the acetabular bone stock. Nearly all hip resurfacing systems are currently based on metal-on-metal wear-bearing couples. The acetabular components are mainly designed as monoblock implants, which can make subsequent revision difficult.Kinematic analyses show a significantly lower range of motion of hip resurfacing implants compared with modern standard (stemmed) total hip replacement systems. This difference originates from the small ratio of the resurfaced femoral head diameter and the relatively thick neck of the femur. Impingement of the femur neck onto the rim of the acetabular component can result in subluxation, deformation of the bearing surfaces, femoral neck fracture, and impairment of the bony anchorage of the hip resurfacing implants.     

金属对金属髋关节表面置换术治疗重度股骨头无菌性坏死的短期临床效果

目的探讨新一代的金属对金属髋关节表面置换术治疗重度股骨头无菌性坏死（FicatⅢ、Ⅳ）的短期临床效果。方法对28例（33髋）诊断为股骨头无菌性坏死的患者行金属对金属髋关节表面置换手术。股骨头无菌性坏死程度按照Ficat分期：Ⅲ期24例（27髋），Ⅳ期4例（6髋），手术时的平均年龄是48岁（21-77岁），其中男患者17例（60.7%），女患者11例（39.3%）。术后随访内容包括所有患者的临床及影像学资料。结果平均随访时间为24个月（11-35个月），在随访期内未发生髋关节脱位、深静脉栓塞、感染、股骨颈骨折等并发症。临床结果显示，Harris髋关节评分较术前显著提高，术后平均Harris评分为92.6分，术前平均Harris评分为48.5分。影像学资料显示所有假体在位，未观察到放射性透亮带。所有患者疼痛解除，髋关节活动度也明显改善，术后早期活动无任何受限。结论金属对金属髋关节表面置换术治疗重度股骨头坏死的早期临床效果满意，其远期效果仍有待于观察。     

Osteonecrosis in retrieved femoral heads after failed resurfacing arthroplasty of the hip

We present the histological findings of bone retrieved from beneath the femoral components of failed metal-on-metal hip resurfacing arthroplasties. Of a total of 377 patients who underwent resurfacing arthroplasty, 13 required revision; for fracture of the femoral neck in eight, loosening of a component in three and for other reasons in two. None of these cases had shown histological evidence of osteonecrosis in the femoral bone at the time of the initial implantation. Bone from the remnant of the femoral head showed changes of osteonecrosis in all but one case at revision. In two cases of fracture which occurred within a week of implantation, the changes were compatible with early necrosis of the edge of the fracture. In the remaining six fractures, there were changes of established osteonecrosis. In all but one of the non-fracture cases, patchy osteonecrosis was seen. We conclude that histological evidence of osteonecrosis is a common finding in failed resurfaced hips. Given that osteonecrosis is extensive in resurfaced femoral heads which fail by fracture, it is likely to play a role in the causation of these fractures.     

A Systematic Review of Modern Metal-on-Metal Total Hip Resurfacing vs Standard Total Hip Arthroplasty in Active Young Patients

This systematic review compared 2 treatments for hip disease in active young patients: modern metal-on-metal total hip resurfacing and standard total hip arthroplasty. We conducted a literature search to identify relevant randomized and clinical controlled trials and included 968 patients from 4 trials in our analysis. Our results indicated increased rates of revision, femoral neck fractures, and component loosening among patients who received modern metal-on-metal hip resurfacing. No significant differences in the rates of mortality, dislocation, or deep hip joint infection were found between treatment groups. Hip function scores were similar between the 2 groups, but the resurfacing group showed higher activity levels. These results have provided insufficient evidence to determine whether modern metal-on-metal total hip resurfacing offers clinical advantages over standard total hip arthroplasty.     

Femoral component neck fracture after failed hip resurfacing arthroplasty

Failure on the femoral side after third-generation metal-on-metal hip resurfacing arthroplasty is suggested to be easily treated with conversion to conventional total hip arthroplasty. Clinical results of conversion for failed hip resurfacing arthroplasty with the use of primary femoral implants confirmed this for a short-term follow-up. We present a case of the occurrence of a stemmed femoral implant neck fracture in a patient who was earlier treated for a failed hip resurfacing. We advise to consider acetabular revision in case of (suspected) acetabular metal damage and to use a stem component with a relative large neck diameter.