Metal-on-metal surface arthroplasty with a cemented femoral component: a 7-10 year follow-up study

Hip resurfacing versus total hip arthroplasty: a systematic review comparing standardized outcomes

BACKGROUND

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

QUESTIONS/PURPOSES

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

METHODS

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

RESULTS

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95-3.1) versus 7.8 for THA (95% CI, 7.2-8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1-11.3) versus 7.1 (95% CI, 6.7-7.6; p = 0.068), and 7.9 (95% CI, 5.4-11.3) versus 1.8 (95% CI, 1.3-2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2-4.6) versus 0.9 (95% CI, 0.6-1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

CONCLUSIONS

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.

Lymphoid aggregates that resemble tertiary lymphoid organs define a specific pathological subset in metal-on-metal hip replacements

Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) has been used to describe the histological lesion associated with metal-on-metal (M-M) bearings. We tested the hypothesis that the lymphoid aggregates, associated with ALVAL lesions resemble tertiary lymphoid organs (TLOs). Histopathological changes were examined in the periprosthetic tissue of 62 M-M hip replacements requiring revision surgery, with particular emphasis on the characteristics and pattern of the lymphocytic infiltrate. Immunofluorescence and immunohistochemistry were used to study the classical features of TLOs in cases where large organized lymphoid follicles were present. Synchrotron X-ray fluorescence (XRF) measurements were undertaken to detect localisation of implant derived ions/particles within the samples. Based on type of lymphocytic infiltrates, three different categories were recognised; diffuse aggregates (51%), T cell aggregates (20%), and organised lymphoid aggregates (29%). Further investigation of tissues with organised lymphoid aggregates showed that these tissues recapitulate many of the features of TLOs with T cells and B cells organised into discrete areas, the presence of follicular dendritic cells, acquisition of high endothelial venule like phenotype by blood vessels, expression of lymphoid chemokines and the presence of plasma cells. Co-localisation of implant-derived metals with lymphoid aggregates was observed. These findings suggest that in addition to the well described general foreign body reaction mediated by macrophages and a T cell mediated type IV hypersensitivity response, an under-recognized immunological reaction to metal wear debris involving B cells and the formation of tertiary lymphoid organs occurs in a distinct subset of patients with M-M implants.

Hip resurfacing: a 40-year perspective

BACKGROUND

Saving bone by resurfacing the femoral head is not a new concept and the appeal for this type of hip replacement has remained despite the difficulties to find a bearing material suitable for this procedure.

PURPOSE

In this article, the unique experience of a surgeon who has been performing hip resurfacing since its early development is presented, along with a comparative analysis of the performance of successive designs.

RESULTS

The overall 10-year Kaplan-Meier survivorship of the early designs with polyethylene bearings did not exceed 62% while that of the current Conserve®Plus metal-on-metal hybrid design implanted with second generation surgical technique is in excess of 92%. Further exceptional, in the 10-year survivorship, 99.7% has been achieved with femoral size of 46 mm and good bone quality. Cementless acetabular components provide better enduring fixation than cemented designs.

DISCUSSION

Metal-on-metal is currently and fortunately the only highly successful bearing material that can combine low wear rates and the manufacturing of a thin acetabular component to preserve bone and still accommodate the large femoral head of a hip resurfacing. The adverse local tissue reactions (ALTR) associated with metal-on-metal devices are not a bearing material issue per se but one of the device design and surgical technique. Almost all of ALTR and the rare events of systemic toxicity are due to abnormal wear patterns which can be prevented by proper acetabular component design and precise socket orientation in both the coronal and sagittal planes. Further improvements of the long-term durability with hip resurfacing can be anticipated with the use of recently developed trabecular bone-like tantalum or titanium porous coatings and with proper training of the surgeons interested in performing hip resurfacing arthroplasty.

Adoption of hip resurfacing arthroplasty at hospital for special surgery: a cohort study

BACKGROUND

Hip resurfacing arthroplasty (HRA) is an alternative to traditional total hip replacement (THR) that allows for the preservation of femoral bone. It is a more technically difficult procedure that has led some researchers to report an unsatisfactory learning curve (Berend et al., J Bone Joint Surg Am Suppl 2:89-92, 2011; Mont et al., Clin Orthop Relat Res 465:63-70, 2007).

PURPOSE

The purpose of this study was to investigate the adoption of HRA at our institution, examining the clinical results, revision rate, and modes of failure. Additionally, a comparison of three different implant systems was performed.

METHODS

A retrospective review of a consecutive series of HRA performed at our institution between the years 2004 and 2009 was carried out. A total of 820 HRA with a minimum of 2 years of follow-up were included in the study. The majority of included patients were males (70%), with osteoarthritis (92%). The average age was 49.8 years, and the mean BMI was 27.5 kg/m(2).

RESULTS

The average Harris hip score improved from 61 to 96.5 postoperatively. Thirteen revisions (1.6%) were performed for femoral neck fracture, femoral head osteonecrosis, acetabular loosening, metal reactivity/metallosis, and metal allergy. The overall Kaplan-Meier survival curve with revision surgery as an endpoint showed 98.5% survival at 5 years. There were no observable differences in clinical scores or revision rates between the different implant systems.

CONCLUSIONS

HRA can be successfully adopted with a low complication rate, given careful patient selection, specialized surgical training, and use of good implant design.

ELIGIBILITY FOR THE HIP-RESURFACING ARTHROPLASTY PROCEDURE: AN EVALUATION ON 592 HIPS

Objective: To investigate the percentage of ideal patients who would be eligible for hip-resurfacing surgery at a reference service for hip arthroplasty. Methods: Out of all the cases of hip arthroplasty operated at Hospital do Servidor Público Estadual de São Paulo (HSPE) between January 2009 and December 2010, we assessed a total of 592 procedures that would fit the criteria for indication for resurfacing arthroplasty, after clinical and radiological evaluation according to the criteria established by the Food and Drug Administration (FDA) and by Seyler et al. Results: Among the total number of hip replacement arthroplasty cases, 5.74% of the patients were eligible. Among the patients who underwent primary arthroplasty, we found that 8.23% presented ideal conditions for this procedure. Conclusion: The study demonstrated that this type of surgery still has a limited role among hip surgery methods.

Total hip arthroplasty in advanced osteonecrosis: the short-term results by metal-on-metal hip resurfacing

BACKGROUND

Characteristically, osteonecrosis affects younger patients who typically refer to the orthopedic surgeon for the first time in the third to fifth decades of life, in the late stages of the disease. Femoral metal-on-metal hip resurfacing is as an alternative to conventional total hip arthroplasty in treating osteoarthritis of the hip. Since there are already many reports regarding the successful outcome of resurfacing in advanced osteoarthritis, the purpose of this study was to analyze the clinical outcomes of this procedure in patients with osteonecrosis of the femoral head and to compare them with a matched group of patients with osteoarthritis.

MATERIAL/METHODS

This retrospective cohort study evaluated a consecutive series of 52 patients with end-stage osteonecrosis (28 patients) and osteoarthritis (24 patients) of the femoral head, managed by metal-on-metal hip resurfacing in a referral orthopedic center from Feb 2002 to May 2007. Pain, function and deformity were evaluated with the use of the Harris hip score after the operation. Patients were clinically followed for a mean of 41 months.

RESULTS

The patients in the osteoarthritis group had a significantly higher mean age than those in the osteonecrosis group (47.88 ± 12.6 vs 30.86 ± 7.5, p=0.003). The clinical outcomes were similar for both groups. There was no significant difference in mean Harris hip score (p=0.347) and hip joint range of motion (p=0.346) between osteonecrosis and osteoarthritis groups after surgery.

CONCLUSIONS

On the basis of these initial findings, we recommend MOM resurfacing as a viable treatment option for patients with advanced stages of osteonecrosis.

Femoral-head vascularity after hip surface arthroplasty

BACKGROUND

iatrogenic devascularization of the femoral head is as an area of concern following hip resurfacing arthroplasty, with probable implications on short-term failure and long-term survival of the implant.

MATERIALS AND METHODS

we assessed the vascularity of 25 resurfaced femoral heads in 20 patients by comparison with preoperative and postoperative Tc-99m methylene diphosphonate (MDP) bone scintigraphy images, the postoperative scans being done 9 months after the surgery.

RESULTS

eight out of 25 hips (32%) showed <55% of their preoperative uptake at a mean of 9 months after surgery and were categorized as showing reduced vascularity.

CONCLUSION

our study reveals reduction in vascularity of the femoral-head remnant as a frequent occurrence after hip resurfacing. Our study also highlights the role of bone scintigraphy as tool in assessing the vascularity of resurfaced femoral heads.

Bone mineral density in the femoral neck increases after hip resurfacing: a cohort with five-year follow-up

Hip resurfacing is an effective treatment modality for arthritis of the hip in carefully selected patients; however, its use remains controversial due to its higher revision rates compared with conventional total hip replacement surgery. The most frequent reason for revision is femoral neck fracture, and preoperative bone mineral density is an important factor when considering the option of hip resurfacing. Whilst reduction in bone mineral density following total hip replacement is well documented, little is known about the long-term changes in femoral neck bone mineral density after hip resurfacing. We followed 15 patients (ten male and five female) who underwent unilateral hip resurfacing for osteoarthritis with standardised dual energy X-ray absorbiometry scans at two weeks, three months, one year, two years and five years postoperatively to determine changes in the femoral neck bone mineral density. Both males and females initially had decreases in bone mineral density at three months postoperatively, but had gradual mean increases to 119% of their initial measurements by five years. This study demonstrates that femoral neck bone mineral density increases after hip resurfacing and that this increase continues for at least five years.

A custom-made guide-wire positioning device for hip surface replacement arthroplasty: description and first results

Background

Hip surface replacement arthroplasty (SRA) can be an alternative for total hip arthroplasty. The short and long-term outcome of hip surface replacement arthroplasty mainly relies on the optimal size and position of the femoral component. This can be defined before surgery with pre-operative templating. Reproducing the optimal, templated femoral implant position during surgery relies on guide wire positioning devices in combination with visual inspection and experience of the surgeon. Another method of transferring the templated position into surgery is by navigation or Computer Assisted Surgery (CAS). Though CAS is documented to increase accurate placement particularly in case of normal hip anatomy, it requires bulky equipment that is not readily available in each centre.

Methods

A custom made neck jig device is presented as well as the results of a pilot study.

The device is produced based on data pre-operatively acquired with CT-scan. The position of the guide wire is chosen as the anatomical axis of the femoral neck. Adjustments to the design of the jig are made based on the orthopedic surgeon's recommendations for the drill direction. The SRA jig is designed as a slightly more-than-hemispherical cage to fit the anterior part of the femoral head. The cage is connected to an anterior neck support. Four knifes are attached on the central arch of the cage. A drill guide cylinder is attached to the cage, thus allowing guide wire positioning as pre-operatively planned.

Custom made devices were tested in 5 patients scheduled for total hip arthroplasty. The orthopedic surgeons reported the practical aspects of the use of the neck-jig device. The retrieved femoral heads were analyzed to assess the achieved drill place in mm deviation from the predefined location and orientation compared to the predefined orientation.

Results

The orthopedic surgeons rated the passive stability, full contact with neck portion of the jig and knife contact with femoral head, positive. There were no guide failures. The jig unique position and the number of steps required to put the guide in place were rated 1, while the complexity to put the guide into place was rated 1-2. In all five cases the guide wire was accurately positioned. Maximum angular deviation was 2.9° and maximum distance between insertion points was 2.1 mm.

Conclusions

Pilot testing of a custom made jig for use during SRA indicated that the device was (1) successfully applied and user friendly and (2) allowed for accurate guide wire placement according to the preoperative plan.

The learning curve for adopting hip resurfacing among hip specialists

Patient demand and surgeon interest in hip resurfacing has recently increased, but surgeons in the United States are relatively inexperienced with this procedure. We determined the learning curve associated with hip resurfacing and compared the rate of early complications of the first 650 hip resurfacings between five experienced hip surgeons and a national safety survey database study we previously published, which included 89 surgeons and 537 hip resurfacings. Patient demographics and adverse events were recorded. Specific features on pre- and postoperative radiographs were measured in a blinded fashion by a single observer. There were 13 major complications (2.0%), which is 3.7 times lower than our national safety survey complication rate of 7.4%. All fractures occurred in the first 25 cases performed. The complication rate was higher for the first 25 procedures (5.6%) compared with the second 25 procedures (1.6%). For experienced hip surgeons, the learning curve for avoiding early complications was short, 25 cases or less. The learning curve for achieving the desired component positioning radiographically was much longer, 75 to 100 cases or more. If achieving some ideal component position proves important for long-term function and implant survival, improved instrumentation and surgical techniques would be necessary to shorten the learning curve.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Role of the extraosseus blood supply in osteoarthritic femoral heads?

Blood perfusion to the femoral head might be endangered during the surgical approach or the preparation of the femoral head or both in hip resurfacing arthroplasty. The contribution of the intramedullary blood supply to the femoral head in osteoarthritis is questionable. Therefore, the contribution of the extraosseous blood supply to osteoarthritic femoral heads was measured intraoperatively to question if there is measurable blood flow between the epiphysis and metaphysis in osteoarthritic hips in case of extraosseus vessel damage. At defined points during surgery we acquired the epiphyseal and metaphyseal femoral head perfusion by high-energy laser Doppler flowmetry. Complete femoral neck osteotomy sparing the retinacular vessels to simulate intraosseous blood disruption showed unchanged epiphyseal blood flow compared to initial measurement after capsulotomy. The pulsatile signal disappeared after transection of the retinacular vessels. Based on these acute measurements, we conclude intramedullary blood vessels to the femoral head do not provide measurable blood supply to the epiphysis once the medial femoral circumflex artery or the retinacular vessels have been damaged. We recommend the use of a safe surgical approach for hip resurfacing and careful implantation of the femoral component to respect blood supply to the femoral head and neck region in hip resurfacing arthroplasty.

Hip resurfacing arthroplasty: risk factors for failure over 25 years

Many early metal-on-polyethylene hip resurfacing arthroplasty designs were abandoned after reports of high short-term and midterm failure rates. To investigate factors associated with failure, we retrospectively reviewed our experience with early-design hip resurfacing implants in 75 patients during a 25-year period (median followup, 7.9 years; range, 0.1-25.2 years). Implant failure was defined as revision for any reason. One of 75 patients was lost to followup. The estimated rate of implant survival was 73% at 5 years, 34% at 10 years, 27% at 15 years, 12% at 20 years, and 8% at 25 years. Of the many clinical and radiographic factors considered, only age, implant type, and gender were associated with implant survival independent of other variables considered. Hip resurfacing arthroplasty showed poor overall long-term survival in this series. Particular attention should be paid to the identified risk factors as long-term followup data become available for modern designs.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Surface replacement is comparable to primary total hip arthroplasty

Conversion of a failed surface hip replacement to a conventional total hip arthroplasty is reportedly a straightforward procedure with excellent results. We compared perioperative parameters, complications, and clinical as well as radiographic outcomes of 39 hemi and total hip resurfacing conversions with conventional THAs. The hips were matched by diagnosis, gender, age, body mass index, preoperative Harris hip score, and followup time to a cohort of primary conventional THAs performed during the same time period by the same surgeon. The mean operative time was longer (by 19 minutes) for the conversions, but other perioperative parameters were similar. At a mean followup of 45 months (range, 24-63 months), the mean Harris hip scores were similar in the two groups (92 points versus 94 points for the conversion and conventional hips, respectively). Thirty-eight of 39 stems were well-aligned and appeared osseointegrated. When a resurfaced hip fails, conversion to conventional THA has similar early clinical and radiographic outcomes to primary conventional THA.

LEVEL OF EVIDENCE

Level III, therapeutic (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Is patient selection important for hip resurfacing?

The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration approval of two devices. Recent studies indicate satisfactory short- and midterm clinical results (1- to 10-year followup) with low complication rates, but there is a learning curve associated with this procedure, a more extensive surgical approach is necessary, and long-term results have yet to be determined. Proper patient selection may help avoid complications and improve patient outcomes. Patient selection criteria in the literature appear based predominantly on theoretical considerations without any consensus on stratifying patient risk. The most commonly reported complications encountered with hip resurfacing include femoral neck fracture, acetabular component loosening, metal hypersensitivity, dislocation, and nerve injury. At the time of clinical evaluation, patient age; gender; diagnosis; bone density, quality, and morphology; activity level; leg lengths; renal function; and metal hypersensitivity are important factors when considering a patient for hip resurfacing. Based on our review, we believe the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology.

LEVEL OF EVIDENCE

Level V, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Impingement in Total Hip Replacement: Mechanisms and Consequences

The occurrence of total hip impingement, whether or not accompanied by frank dislocation, holds substantial untoward clinical consequences, especially as less-forgiving advanced bearing implant designs come into ever more widespread use. Biomechanical aspects of impingement and dislocation have historically received relatively little scientific attention, although that situation is now rapidly changing. The present article reviews contemporary laboratory and clinical research on the impingement/dislocation phenomena, focusing particularly on how implant design variables, surgical implantation factors and patient activity each act individually and in concert to pose impingement and dislocation challenges. In recent years, several powerful new research methodologies have emerged that have greatly expanded the scope for clinical translation of systematic laboratory study. Transferring the findings from such research into yet better implant designs, and even better surgical procedures, offers encouragement that the clinical impact of this troublesome complication can be further reduced.

[Results for endoprosthetic care in patients younger than 50 years]

Arthroplasty has become the most successful surgical procedure in developed countries. Replacement of severely damaged joints results in a substantial relief of pain, as the main symptom of osteoarthritis, in the majority of treated patients. With improved results in endoprosthetic surgery over the last decades, however, patients are increasingly undergoing the procedure to enhance their functional capacity and physical mobility. Especially younger patients, who cannot accept a restriction in their professional or sports activity, have become demanding candidates for surgery. This review summarizes the published results on shoulder, hip, knee, ankle and first metatarsophalangeal joint replacement in patients who are younger than 50 years of age. Mid- and long-term follow-up studies in this age group are evaluated in terms of prosthesis survival as well as functional improvement.