Five year results of the first US FDA-approved hip resurfacing device

Hip resurfacing arthroplasty in young patients: international high-volume centres' report on the outcome of 11,382 metal-on-metal hip resurfacing arthroplasties in patients ⩽50 years at surgery

BACKGROUND

Total hip arthroplasty (THA) in patients younger than 50 years poses significant challenges including postoperative limitations of activity and higher failure rates. Sub-par outcomes of hip resurfacing arthroplasty (HRA) in registries remain controversial due to multiple confounders. Favourable HRA results in some studies are often regarded as irreproducible. The aim of this study is to analyse HRA outcomes in a large international cohort.

PATIENTS AND METHODS

We compiled a database of 11,382 HRA patients ⩽50 years from an international group of 27 experienced HRA centres from 13 countries. 18 different metal-on-metal (MoM) HRA designs were included with a mean follow-up of 7.6 years. Outcomes were implant survivorship, revision rates, causes for revision, clinical scores and metal ion levels. Outcomes were compared between genders, sizes, implant types and pre-operative diagnoses.

RESULTS

Overall cumulative Kaplan-Meier survivorship was 88.9% at 22 years (95% CI: 88.3-89.5%). 2 HRA designs (DePuy Articular Surface Replacement (ASR), and Corin Cormet Hip Resurfacing System (CORMET)) led to inferior results while all others yielded similar survivorships. Excluding ASR and CORMET, implant survivorship in 11,063 cases was 95% at 10 years and 90% at 22 years. In men, implant survivorship was excellent: 99% at 10 years and 92.5% at 21 years. In females, implant survivorship was 90% at 10 years and 81.3% at 22 years. The overall revision rate was 3.6% with most common reasons for revision being implant loosening and adverse local tissue reactions. The best survivorship was found in patients with osteoarthritis (95% CI, 92.1-93.3% at 22 years), the poorest was among dysplastic hips (78.3%; 95% CI, 76.5-80.1% at 20 years, p < 0.001).

CONCLUSIONS

Comparable revision rates demonstrated here may mitigate some concerns for safety and longevity of MoM HRA implants. Higher demands for activity and functionality in younger patients make HRA a potential alternative to THA.

What is the Level of Evidence Substantiating Commercial Payers' Coverage Policies for Total Joint Arthroplasty?

BACKGROUND

The prevalence of total joint arthroplasty (TJA) in the United States has drawn the attention of health care stakeholders. The payers have also used a variety of strategies to regulate the medical necessity of these procedures. The purpose of this study was to examine the level of evidence of the coverage policies being used by commercial payers in the United States.

METHODS

The references of the coverage policies of four commercial insurance companies were reviewed for type of document, level of evidence, applicability to a TJA population, and success of nonoperative treatment in patients with severe degenerative joint disease.

RESULTS

282 documents were reviewed. 45.8% were primary journal articles, 14.2% were level I or II, 41.2% were applicable to patients who were candidates for TJA, and 9.9% discussed the success of nonoperative treatment in patients who would be candidates for TJA.

CONCLUSION

Most of the references cited by commercial payers are of a lower level of scientific evidence and not applicable to patients considered to be candidates for TJA. This is relatively uniform across the reviewed payers. The dearth of high-quality literature cited by commercial payers reflects the lack of evidence and difficulty in conducting high level studies on the outcomes of nonoperative versus operative treatment for patients with severe, symptomatic osteoarthritis. Patients, surgeons, and payers would all benefit from such studies and we encourage professional societies to strive toward that end through multicenter collaboration.

Results of the First U.S. FDA-Approved Hip Resurfacing Device at 10-Year Follow-up

BACKGROUND

The BIRMINGHAM HIP Resurfacing (BHR) system is a metal-on-metal hip implant system approved by the U.S. Food and Drug Administration in 2006. The approval required a multicenter, prospective, post-market-approval study. Our purpose is to report the current results at 10 years of follow-up.

METHODS

Between October 2006 and December 2009, 280 primary BHR procedures were performed at 5 sites. Outcome measures included Kaplan-Meier survivorship, reasons for revision, radiographic component stability and osteolysis, Harris hip scores, and metal levels including cobalt and chromium. The mean age at the time of the procedure was 51.3 ± 7.1 years, 74% (206) of 280 BHRs were implanted in male patients, the mean body mass index was 27.8 ± 4.4 kg/m2, and 95% (265) of 280 hips had a primary diagnosis of osteoarthritis. The mean follow-up among all 280 hips was 9.0 ± 2.5 years. Prior to 10-year follow-up, 20 hips were revised and 5 patients representing 5 hips had died. Among the remaining 255 hips, 218 (85%) met the minimum follow-up of 10 years.

RESULTS

The 10-year survival free from all-cause component revision was 92.9% (95% confidence interval [CI], 89.8% to 96.1%) for all hips and 96.0% (95% CI, 93.1% to 98.9%) among male patients <65 years old at the time of the procedure. Reasons for revision included femoral loosening (n = 5), femoral neck fracture (n = 3), pseudotumor (n = 3), osteolysis (n = 2), and acetabular loosening (n = 1), as well as 6 revisions for a combination of pain, noise, or metal levels. Among unrevised hips, the median Harris hip score improved from preoperatively (59) to 1 year postoperatively (99; p < 0.001) and remained stable through 10 years postoperatively (99; p = 0.08). Radiographically, 5% (10) of 218 unrevised hips had osteolysis with no component migration. Median metal levels had increased at 1 year postoperatively (cobalt: from 0.12 ppb preoperatively to 1.5 ppb at 1 year postoperatively, p < 0.001; chromium: from 0.6 ppb preoperatively to 1.7 ppb at 1 year postoperatively, p < 0.001), then remained stable through 5 years before slightly decreasing at 10 years postoperatively (cobalt: 1.3 ppb, p < 0.001; chromium: 1.4 ppb, p < 0.001).

CONCLUSIONS

This prospective, multicenter, post-market-approval study demonstrated that the BHR implant system is safe and effective through 10 years of follow-up, particularly among young male patients.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Midterm outcomes of total hip arthroplasty with a modular Birmingham head

INTRODUCTION

Birmingham Hip Resurfacing (BHR) implants may be combined with a conventional femoral stem to create a modular metal-on-metal total hip arthroplasty (BHR MoM THA). There is little outcome data regarding this construct. This study examines midterm outcomes of BHR MoM THA compared to oxidised zirconium total hip arthroplasty (THA).

METHODS

A retrospective institutional review identified all patients receiving BHR MoM THA between April 2005 and February 2011 and a matched control cohort of zirconium THA patients. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), and SF-12 Health status scores were obtained. Revisions and complications were collected from clinical records. Radiographs were assessed for evidence of component malposition, loosening, osteolysis, or heterotopic ossification.

RESULTS

63 modular BHR MoM THA were identified in 61 patients (36 with BHR cups, 27 with R3 cups) and 63 zirconium THA in 58 matched controls. Mean follow-up was 58 months. 14 BHR MoM THA hips (22.2%) were revised (4 infections, 1 dislocation, 9 soft tissue reactions) compared to 3 (4.8%) zirconium THA (all infections). At latest follow-up, 18.4% of surviving BHR MoM THA hips were painful compared to 0.5% of zirconium THA controls (p < 0.001). WOMAC, HHS, and SF-12 did not differ significantly between surviving members of the 2 groups.

DISCUSSION

BHR MoM THA demonstrated a high revision rate, largely for adverse local soft tissue reaction and pain. Among those not revised, many reported some residual pain despite similar quality of life measures to those who received zirconium THA.

Have newer bearing surfaces changed expectations regarding the longevity of total hip arthroplasty?

AIMS

The purpose of this study is to examine six types of bearing surfaces implanted at a single institution over three decades to determine whether the reasons for revision vary among the groups and how long it takes to identify differences in survival.

METHODS

We considered six cohorts that included a total of 1,707 primary hips done between 1982 and 2010. These included 223 conventional polyethylene sterilized with γ irradiation in air (CPE-GA), 114 conventional polyethylene sterilized with gas plasma (CPE-GP), 116 crosslinked polyethylene (XLPE), 1,083 metal-on-metal (MOM), 90 ceramic-on-ceramic (COC), and 81 surface arthroplasties (SAs). With the exception of the COC, all other groups used cobalt-chromium (CoCr) femoral heads. The mean follow-up was 10 (0.008 to 35) years. Descriptive statistics with revisions per 100 component years (re/100 yr) and survival analysis with revision for any reason as the endpoint were used to compare bearing surfaces.

RESULTS

XLPE liners demonstrated a lower cumulative incidence of revision at 15 years compared to the CPE-GA and CPE-GP groups owing to the absence of wear-related revisions (4% for XLPE vs 18%, p = 0.02, and 15%, p = 0.003, respectively). Revisions for adverse local tissue reactions occurred exclusively among the MOM (0.8 re/100 year) and SA groups (0.1 re/100 year). The revision rate for instability was lower among hips with 36 mm and larger head sizes compared to smaller head sizes (0.2% vs 2%, p < 0.001).

CONCLUSION

The introduction of XLPE has eliminated wear-related revisions through 15-year follow-up compared to CPE-GP and CPE-GA. Dislocation incidence has been reduced with the introduction of larger diameter heads but remains a persistent concern. The potential for adverse local tissue reactions with MOM requires continued follow-up. Cite this article: Bone Joint J 2020;102-B(7 Supple B):105-111.

Hip resurfacing as an outpatient procedure: a comparison of overall cost and review of safety

Abstract

Recent advancements in arthroplasty surgical techniques and perioperative protocols have reduced the duration of hospitalization and length of recovery, allowing surgeons to perform joint replacement as an outpatient procedure. This study aims to evaluate the cost-effectiveness and safety of outpatient hip resurfacing. Two experienced surgeons performed 485 resurfacing surgeries. We retrospectively compared clinical outcomes and patient satisfaction with published outpatient total hip results. Furthermore, we compared average insurance reimbursement with that of local inpatient hip replacement. No major complications occurred within 6 weeks. Of the 39 patients with previous inpatient experience, 37 (95%) believed their outpatient experience was superior. The average reimbursement for hip arthroplasty at local hospitals was $50,000, while the average payment for outpatient resurfacing at our surgery center was $26,000. We conclude that outpatient hip resurfacing can be accomplished safely, with high patient satisfaction, and at a tremendous financial savings to the insurer/patient.

Level of evidence

III

Electronic supplementary material

The online version of this article (10.1007/s12306-020-00637-z) contains supplementary material, which is available to authorized users.

Birmingham Hip Resurfacing in Patients 55 Years or Younger: Risk Factors for Poor Midterm Outcomes

BACKGROUND

Birmingham hip resurfacing (BHR) is the only Food and Drug Administration-approved hip resurfacing system available in the United States and is used as an alternative to conventional total hip arthroplasty in younger patients. The purpose of this study is to report on the midterm outcomes of BHR in patients 55 years and younger, and specifically to examine the risk factors for aseptic failure, all-cause revision, and complications in this patient population.

METHODS

Four hundred forty-two consecutive patients with 5-year follow-up were retrospectively reviewed. Multivariate analyses were conducted to control for potential confounding factors identified by univariate analyses.

RESULTS

Mean follow-up was 71.68 ± 10.24 months. Among the potential risk factors, only female gender and smaller head sizes had a significant univariate relationship with aseptic revision, all-cause revision, and all-cause complications. When both risk factors were included in a multivariable logistic regression model, analyses showed both variables were closely related, with female gender a better predictor of adverse outcomes than head size (ie, small head size can be thought of as a proxy for female gender). The 5-year implant survival is 95.1% females compared to 99.0% in males.

CONCLUSION

Hip resurfacing with BHR has excellent survival rates in young patients with degenerative hip disease. Although this study suggests that females with small templated head sizes may not be suitable candidates for BHR, further studies are needed to better understand the underlying differences in gender.

Survivorship and patient satisfaction of robotic-assisted medial unicompartmental knee arthroplasty at a minimum two-year follow-up

BACKGROUND

Successful clinical outcomes following unicompartmental knee arthroplasty (UKA) depend on lower limb alignment, soft tissue balance and component positioning, which can be difficult to control using manual instrumentation. Although robotic-assisted surgery more reliably controls these surgical factors, studies assessing outcomes of robotic-assisted UKA are lacking. Therefore, a prospective multicenter study was performed to assess outcomes of robotic-assisted UKA.

METHODS

A total of 1007 consecutive patients (1135 knees) underwent robotic-assisted medial UKA surgery from six surgeons at separate institutions between March 2009 and December 2011. All patients received a fixed-bearing metal-backed onlay implant as tibial component. Each patient was contacted at minimum two-year follow-up and asked a series of five questions to determine survivorship and patient satisfaction. Worst-case scenario analysis was performed whereby all patients were considered as revision when they declined participation in the study.

RESULTS

Data was collected for 797 patients (909 knees) with average follow-up of 29.6months (range: 22-52months). At 2.5-years of follow-up, 11 knees were reported as revised, which resulted in a survivorship of 98.8%. Thirty-five patients declined participation in the study yielding a worst-case survivorship of 96.0%. Of all patients without revision, 92% was either very satisfied or satisfied with their knee function.

CONCLUSION

In this multicenter study, robotic-assisted UKA was found to have high survivorship and satisfaction rate at short-term follow-up. Prospective comparison studies with longer follow-up are necessary in order to compare survivorship and satisfaction rates of robotic-assisted UKA to conventional UKA and total knee arthroplasty.

Mid-Term Results and Predictors of Patient-Reported Outcomes of Birmingham Hip Resurfacing

BACKGROUND

Birmingham hip resurfacing (BHR) is the only Food and Drug Administration approved resurfacing option currently available in the United States. While adequate BHR outcomes are established, there is a paucity of US-based literature demonstrating factors critical to improve patient reported outcomes (PROs). This study answers: (1) What is the implant survivorship in a large US cohort? (2) Which preoperative factors result in higher PRO scores over 5 years postoperatively?

METHODS

A retrospective 541 hip single-surgeon cohort with mean of 6.2 years follow-up (range 5-8.1) was collected. Preoperative patient/implant variables, including postoperative radiographic acetabular inclination and femoral component position, clinical outcomes, and follow-up PRO questionnaire information were collected. Validated PROs included the Hip Disability and Osteoarthritis Outcome Score (HOOS), Veterans Rand-12, and University of California Los Angeles (UCLA) activity. PROs were modeled with ordinary least squares then used to create nomograms.

RESULTS

Average patient age was 53 years with 391 (72%) males. Seven hips were revised, resulting in an overall survival of 98.8% at 5 years. Predictive modeling identified preoperative variables (sex, body mass index, smoking, and comorbidity) that had statistically significant associations with HOOS pain (P = .049), HOOS activities of daily living (P = .017), UCLA activity (P < .001), and Veterans Rand-12 physical (P < .001) PROs at latest follow-up. Nomograms predicted follow-up PROs using preoperative patient-specific variables.

CONCLUSION

This study documents excellent survival of the largest reported single-center cohort of BHRs in the United States with a mean 6.2 years follow-up. Multivariate modeling shows male nonsmokers with low body mass index, and no comorbidities will have less hip pain, better function in daily life, higher activity, and better general physical health after BHR arthroplasty.

Prevalence of Failure due to Adverse Reaction to Metal Debris in Modern, Medium and Large Diameter Metal-on-Metal Hip Replacements--The Effect of Novel Screening Methods: Systematic Review and Metaregression Analysis

Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level.

Current indications for hip resurfacing arthroplasty in 2016

Hip resurfacing arthroplasty (HRA) is an alternative to conventional, stemmed total hip arthroplasty (THA). The best reported results are young, active patients with good bone stock and a diagnosis of osteoarthritis. Since the 1990s, metal-on-metal (MoM) HRA has achieved excellent outcomes when used in the appropriate patient population. Concerns regarding the metal-on-metal bearing surface including adverse local tissue reaction (ALTR) to metal debris have recently lead to a decline in the use of this construct. The current paper aims to provide an updated review on HRA, including a critical review of the most recent literature on HRA.

Frequent femoral neck osteolysis with Birmingham mid-head resection resurfacing arthroplasty in young patients

BACKGROUND

Mid-head resection total hip resurfacing arthroplasty was promoted as an alternative to traditional total hip resurfacing for patients with poor femoral head bone quality or abnormal femoral head morphology, because those patients are at high risk of failure with traditional total hip resurfacing. It is a large-headed metal-on-metal device that uses a short, bone-conserving stem. Good performance of the implant has been reported at short-term followup, but no information on the implant performance in the mid- or long-term is available.

QUESTIONS/PURPOSES

In this study, we report (1) on the mid-term implant survivorship and hip scores in a single nondesigner surgeon series. Because of the occurrence of femoral neck osteolysis and pseudotumor in a subgroup of patients, we also investigated the following: (2) Were there any preoperative parameters that are associated with osteolysis? (3) Could we differentiate the osteolysis group from the others on the basis of implant component sizes, positions, and radiologic parameters? (4) Could we differentiate the osteolysis group from the others on the basis of metal ion levels?

METHODS

Between 2006 and 2011, one surgeon performed a total of 49 Birmingham Mid-head Resection total hip resurfacing arthroplasties in 47 patients. The general indications for this procedure were young patients who were considered suitable for hip resurfacing arthroplasty but had avascular necrosis, large cysts, or severe deformity of the femoral head. Clinical followup including Oxford Hip Score (OHS) and UCLA hip scores were available preoperatively and at a mean of 6 years (range, 3-8 years) on all patients (100%), radiographic followup on 45 of 47 (96%), MRIs on 18 (38%), and metal ion levels on 37 (79%). Mean age at surgery was 50 years. Spearman's correlation was used to test the association between femoral neck osteolysis and preoperative parameters, implant component sizes and positions, and blood metal ion levels.

RESULTS

We found 100% survival. Patients' median OHS was 46 of 48 (range, 35-48) and UCLA 8 of 10 (range, 4-10). However, 16% of the hips (seven of 45) demonstrated osteolysis in the femoral neck. Of the preoperative parameters, the osteolysis was associated with low weight (r = -0.337, p = 0.031) and to a lesser degree with female sex (r = 0.275, p = 0.067). Radiologically, the osteolysis was strongly associated with the presence of a pseudotumor on MRI (r = 0.663, p = 0.004). We could not differentiate the osteolysis group from the rest of the cohort on the basis of the implant sizes or radiographic implant component positions. The cohort's median whole blood cobalt was 1.77 ppb (range, 0.18-10.27 ppb) and chromium 1.88 ppb (range 0.36-10.09 ppb). There was no difference in the metal ion levels between the osteolysis group and the rest of the cohort.

CONCLUSIONS

The high rate of silently developing femoral neck osteolysis associated with this implant is concerning and is expected to cause a high rate of failure at longer followup. We have instituted a program of annual clinical and radiologic followup for this group of patients. We have stopped implanting this device and recommend against its use.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Exploring the tumor microenvironment with nanoparticles

Recent developments in nanotechnology have brought new approaches to cancer diagnosis and therapy. While enhanced permeability and retention effect (EPR) promotes nanoparticle (NP) extravasation, the abnormal tumor vasculature, high interstitial pressure and dense stroma structure limit homogeneous intratumoral distribution of NP and compromise their imaging and therapeutic effect. Moreover, heterogeneous distribution of NP in nontumor-stroma cells damages the nontumor cells, and interferes with tumor-stroma crosstalk. This can lead to inhibition of tumor progression, but can also paradoxically induce acquired resistance and facilitate tumor cell proliferation and metastasis. Overall, the tumor microenvironment plays a crucial, yet controversial role in regulating NP distribution and their biological effects. In this review, we summarize recent studies on the stroma barriers for NP extravasation, and discuss the consequential effects of NP distribution in stroma cells. We also highlight design considerations to improve NP delivery and propose potential combinatory strategies to overcome acquired resistance induced by damaged stroma cells.

Survivorship and clinical outcome of Birmingham hip resurfacing: a minimum ten years' follow-up

INTRODUCTION

Resurfacing as a percentage of total hip arthroplasty rose from 5.6 % in 2001 to 8.9 % in 2005 in Australia. During the same period the resurfacing to conventional prosthesis rose from 19.6 % to 29 % in the younger age group (less than 55 years). Long term (more than ten years) functional results of BHR are sparingly documented. Among the literatures available, the patient selection criteria vary from osteoarthritis, avascular necrosis, and dysplastic hip to slipped capital femoral epiphysis. The objective of the current study is to evaluate long term survivorship and functional outcome of Birmingham hip resurfacing surgery in osteoarthritic hip patients performed by a single surgeon.

PATIENTS AND METHODS

In this retrospective clinical study, all patients who underwent hip resurfacing for osteoarthritis of hip between 1999 and 2004 are included. All surgeries were performed by single surgeon (SJM) and in all patients Smith & Nephew system (Midland Medical Technologies, Birmingham, United Kingdom)) was used. Revision surgery is considered the end point of survivorship. Means, standard deviations, and confidence interval were calculated for all continuous measures. Survival analysis was performed with the Kaplan-Meier method and 95 % confidence intervals were calculated.

RESULT

The result is based on 222 patients (244 hips). This included 153 males and 69 females. Our mean follow up was 12.05 years and overall survival was 93.7 %. In terms of gender, survival in males was 95.43 % while in females it was 89.86 %. Failure was seen in 14 patients (16 hips), which included seven female (10.14 %) and seven male (4.57 %) patients. Failure of femoral components due to aseptic loosening and varus collapse was seen in eight patients after a mean 9.6 years. Metal allergy was seen in three patients (five hips), all of them were female of which two had bilateral resurfacing. Other complications included femoral neck stress fractures in two patients and acetabular component loosening in one patient. We observed that the failure rate is higher if the BHR femoral component size is 46 or less (ten out of 16 hips revised).

CONCLUSION

If patient selection is judiciously done and surgical technique is meticulously followed, hip resurfacing offers acceptable survivorship, satisfactory range of motion and enables patients to resume high demand activities including sports. Future improvements in the bearing surfaces, and possibly in the design, might alleviate concerns posed by high serum metal level and provide options that continue to benefit younger patients in future.