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

What is the long-term survivorship, complication profile, and patient reported outcomes after Birmingham hip resurfacing?

Introduction

When indicated, Birmingham Hip Resurfacing (BHR) presents a viable alternative to total hip arthroplasty (THA), but there remain questions about the long-term outcomes of BHR. Therefore, we asked: 1) what are the long-term patient-reported outcomes and 2) survivorship rates following BHR; 3) what are the causes for revision surgery after BHR? and 4) how have these outcomes compared to THA at long-term follow-up.

Methods

A query of PubMed, MEDLINE, Scopus, and Cochrane in September 2023 was performed. Articles were included if they reported BHR survivorship rates at ≥10 years. Survivorship was defined as an all-cause revision of any BHR component. This review encompasses 26 articles, totaling 13,103 hips. Mean follow-up ranged from 6.0 to 20.9 years, but each study had at least a subgroup analysis for ≥10-year follow-up.

Results

Five studies compared preoperative and postoperative PROs for BHR, with four reporting improvement in at least one PRO after 10-year follow-up. Overall, survivorship rates ranged from 83% to 100% across diverse long-term timeframes, with 25 of 26 studies reporting 10-year survivorship rates greater than 87%. The primary reasons for revisions were implant loosening (22%), adverse reactions to metal debris (21.2%), and fractures of any kind (17.2%). In the six studies that compared BHR to THA, long-term survivorship was similar while BHR exhibited slightly superior activity levels.

Conclusion

The findings from this study suggested favorable long-term survivorship and postoperative outcomes of BHR. In studies comparing long-term BHR and THA, survivorship was comparable, with BHR potentially providing enhanced postoperative activity levels.

Birmingham Hip Resurfacing at 25 years

Aims

The Birmingham Hip Resurfacing (BHR) was introduced in 1997 to address the needs of young active patients using a historically proven large-diameter metal-on-metal (MoM) bearing. A single designer surgeon's consecutive series of 130 patients (144 hips) was previously reported at five and ten years, reporting three and ten failures, respectively. The aim of this study was to extend the follow-up of this original cohort at 25 years.

Methods

The study extends the reporting on the first consecutive 144 resurfacing procedures in 130 patients for all indications. All operations were undertaken between August 1997 and May 1998. The mean age at operation was 52.1 years (SD 9.93; 17 to 76), and included 37 female patients (28.5%). Failure was defined as revision of either component for any reason. Kaplan-Meier survival analysis was performed. Routine follow-up with serum metal ion levels, radiographs, and Oxford Hip Scores (OHSs) was undertaken.

Results

Overall implant survival was 83.50% (95% confidence interval (CI) 0.79 to 0.90) at 25 years, and the number at risk was 79. Survival in male patients at 25 years was 89.5% (95% CI 0.83 to 0.96) compared to 66.9% for female patients (95% CI 0.51 to 0.83). Ten additional failures occurred in the period of ten to 25 years. These involved an adverse reaction to metal debris in four patients, a periprosthetic femoral neck fracture affecting five patients, and aseptic loosening in one patient. The median chromium levels were 49.50 nmol/l (interquartile range (IQR) 34 to 70), and the median cobalt serum levels were 42 nmol/l (IQR 24.50 to 71.25). The median OHS at last follow-up was 35 (IQR 10 to 48). During the 25-year study period, 29 patients died. Patient survival at 25 years was 75.10% (95% CI 0.67 to 0.83).

Conclusion

This study demonstrates that MoM hip resurfacing using the BHR provides a durable alternative to total hip arthroplasty (THA), particularly in younger male patients with osteoarthritis wishing to maintain a high level of function. These results compare favourably to the best results for THAs.

Long-Term Outcomes of Birmingham Hip Resurfacing Arthroplasty: A Systematic Review of Independent Series with At Least 10 Years of Follow-up

Background

Hip resurfacing arthroplasty (HRA) provides an attractive alternative to total hip arthroplasty (THA) for the management of osteoarthritis in younger, more active patients; however, concerns persist over complications specific to HRA. The aims of this systematic review were to assess the documented long-term survival rates of the metal-on-metal BIRMINGHAM HIP Resurfacing System at a follow-up of at least 10 years and to analyze the functional outcomes and cause of failures.

Methods

A systematic review was undertaken of all published cohort studies available in the MEDLINE, Cochrane, Embase, and PubMed research databases up to December 2021, as recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction was focused on survival rates, causes of failure, and functional outcomes. Survival estimates at 10 years were pooled in a meta-analysis, with each series weighted by its variance. Causes of failure were presented as a percentage of the pooled revisions.

Results

A total of 11 studies were identified, encompassing 3,129 cases. Across the 9 studies that had reported a mean follow-up, the mean follow-up was 11.7 years (range, 9.55 to 13.7 years). We found a pooled 10-year survival rate of 95.5% (95% confidence interval, 93.4% to 97.1%). There were 149 revisions among the studies (range, 4 to 38 revisions per study), a rate of 4.8% of the total procedures performed. The 2 main causes of revision were aseptic loosening (20.1% of revisions) and adverse reactions to metal debris (20.1%). There were no revisions for dislocation. Of the studies that reported preoperative functional scores, all reported significant improvement in mean scores postoperatively except for 1 study in which the mean Tegner activity score did not significantly improve.

Conclusions

When performed for appropriate indications, patients undergoing an HRA with use of the BIRMINGHAM HIP Resurfacing System can expect good implant survivorship at 10 years with acceptable functional results and low rates of dislocation and infection. This systematic review, however, confirms concerns regarding adverse reactions to metal debris as a leading cause of revision.

Level of Evidence

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

Birmingham hip resurfacing: a systematic review of outcomes at minimum 10-years follow-up

Although controversy surrounding the use of metal-on-metal (MoM) arthroplasty implants continues to exist, satisfactory clinical and radiological outcomes have been reported following Birmingham Hip Resurfacing (BHR) at long-term follow-up, leading to an Orthopaedic Data Evaluation Panel (ODEP) rating of 13A. The purpose of this study was to systematically review the literature to evaluate the functional outcomes, radiological outcomes and revision rates following BHR at a minimum of 10 years follow-up. Using the PRISMA guidelines, two independent reviewers performed a literature search using Pubmed, Embase and Scopus databases. Only studies reporting on outcomes of BHR with a minimum of 10 years' follow-up were considered for inclusion. A total of 12 studies including 7132 hips (64.8% males), with mean follow-up of 11.5 years (10-15.3), met our inclusion criteria. Of included patients, 94.3% of patient underwent BHR for osteoarthritis at a mean age was 52.0 years (48-52). At final follow-up, 96% of patients reported being satisfied with their BHR, with mean Harris Hip Scores of 93.6 and Oxford Hip Scores of 16.5. Rates of radiological femoral neck narrowing of greater than 10% and non-progressive radiological loosening were reported as 2.0% and 3.8% respectively. At final follow-up, the overall revision rate was 4.9% (334/7132), deep infection rate was 0.4%, metal allergy/insensitivity rate was 1.6%, metal reaction rate was 0.3%, rate of peri-prosthetic fracture was 0.9% and aseptic loosening rates were 1.6%. This systematic review demonstrates that BHR results in satisfactory clinical outcomes, acceptable implant survivorship, low complication rates and modest surgical revision rates in the long-term at minimum 10-year follow-up.

Survivorship and risk factors for revision of metal-on-metal hip resurfacing

Aims

Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon.

Methods

A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records.

Results

A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4° abduction (interquartile range 41.9° - 48.3°) and stems neutral or valgus to the native neck-shaft angle. In all, 11 hips (4.5%; one male, ten females) in ten patients underwent revision surgery at a mean of 7.4 years (range 2.8 to 14.2), giving a cumulative survival rate of 94.8% (95% confidence interval (CI) 91.6% to 98.0%) at ten years, and 93.4% (95% CI 89.3% to 97.6%) at 17 years. For aseptic revision, male survivorship was 100% at 17 years, and 89.6% (95% CI 83.1% to 96.7%) at ten and 17 years for females. Increased metal ion levels were implicated in 50% of female revisions, with the remaining being revised for unexplained pain or avascular necrosis.

Conclusion

The Birmingham MoM-HR showed 100% survivorship in males, exceeding the National Institute for Health and Care Excellence '5% at ten years' threshold. Female sex and small component sizes are independent risk factors. Dysplasia alone is not a contraindication to resurfacing.

Metal-on-Metal Hip Arthroplasty: A Comprehensive Review of the Current Literature

Metal-on-metal (MoM) total hip arthroplasty has been widely used since the end of the 20th century, although rates have now decreased due to concerns regarding adverse reactions and failure rates. The MoM implant has been replaced with other materials, such as ceramic-on-ceramic (CoC) and metal-on-polyethylene (MoP). This literature review looks at the past and present use of MoM prostheses to assess whether the turn away from MoM use is justified. Online literature searches were performed on PubMed, Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), and Web of Science online databases using the search terms "MoM and (ARMD and ALVAL)" (ARMD: adverse reaction to metal debris; ALVAL: aseptic lymphocyte-dominant vasculitis-associated lesion). A total of 64 relevant titles were included in the review. Although risk factors for adverse reactions and the causes of ARMD are generally agreed upon, more work is required to further understand the specific thresholds of blood metal ion levels that can be used to consistently identify ARMD and excessive metal wear-debris in patients who have not had their MoM implants revised. Metal-on-metal devices are not an acceptable option for total hip arthroplasties (THAs) in their current formulation due to the high rate and risk of ARMD. Some MoM hip resurfacing operations are appropriate for very carefully selected patients who are fully aware of the risks posed by the implant. It is recommended that device-specific thresholds for metal ion levels be developed to identify patients at risk of ARMD locally and systemically while using auxiliary tools to assist diagnosis, such as metal artefact reduction sequences (MARS)-MRI and hip scoring tools. Further work should investigate device-specific blood metal ion levels, the systemic effects of raised metal ion concentrations secondary to MoM arthroprosthetic wear, and the potential risks of ARMD caused by wear from tapered stems (including the implications this has for patients with CoC and MoP prostheses).

Metallosis in Total Hip Arthroplasty

» Metallosis is a rare but significant complication that can occur after total hip arthroplasty (THA) for a variety of reasons but most commonly in patients with metal-on-metal implants.» It is characterized by the visible staining, necrosis, and fibrosis of the periprosthetic soft tissues, along with the variable presence of aseptic cysts and solid soft tissue masses called pseudotumors secondary to the corrosion and deposition of metal debris.» Metallosis can present with a spectrum of complications ranging from pain and inflammation to more severe symptoms such as osteolysis, soft tissue damage, and pseudotumor formation.» Workup of metallosis includes a clinical evaluation of the patient's symptoms, imaging studies, serum metal-ion levels, and intraoperative visualization of the staining of tissues. Inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein along with intraoperative frozen slice analysis may be useful in certain cases to rule out concurrent periprosthetic joint infection.» Management depends on the severity and extent of the condition; however, revision THA is often required to prevent rapid progression of bone loss and tissue necrosis.

Debridement, antibiotics and implant retention for prosthetic joint infection: comparison of outcomes between total hip arthroplasty and hip resurfacing

INTRODUCTION

The management of prosthetic joint infection (PJI) has been widely studied in the context of total hip arthroplasty (THA). However, the outcomes of debridement, antibiotics and implant retention (DAIR) for PJI have never been compared between hip resurfacing arthroplasty (HRA) and THA. This led us to carry out a retrospective case-control study comparing the surgical treatment of post-operative infections between HRA and THA to determine the infection remission rate and the medium-term functional outcomes.

METHODS

This single-centre case-control study analysed 3056 HRA cases of which 13 patients had a PJI treated by DAIR. These patients were age-matched with 15 infected THA hips treated by DAIR and modular component exchange (controls). Their survival (no recurrence of the infection) was compared and factors that could affect the success of the DAIR were explored: sex, body mass index, age at surgery, presence of haematoma, type of bacteria present and antibiotic therapy.

RESULTS

At a mean follow-up of five years (2-7), the infection control rate was significantly higher in the HRA group (100% [13/13]) than in the THA group (67% [10/15]) (p = 0.044). More patients in the THA group had undergone early DAIR (< 30 days) (73% [11/15]) than in the HRA group (54% [7/13]). There was no significant difference between the two groups in the ASA score, presence of comorbidities, body mass index and duration of the initial arthroplasty procedure. At the review, the Oxford-12 score of 17/60 (12-28) was better in the HRA group than the score of 25/60 (12-40) in the THA group (p = 0.004).

CONCLUSION

DAIR, no matter the time frame, is a viable therapeutic option for infection control after HRA.

Is the Survivorship of Birmingham Hip Resurfacing Better Than Selected Conventional Hip Arthroplasties in Men Younger Than 65 Years of Age? A Study from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

The Birmingham Hip Resurfacing (BHR) prosthesis is the most commonly used metal-on-metal hip resurfacing arthroplasty device. The current manufacturer-recommended target demographic for the BHR is male patients, younger than 65 years requiring a femoral head size of ≥ 50 mm. Female patients, older patients, and individuals with smaller femoral-head diameter (≤ 50 mm) are known to have higher revision rates. Prior studies suggest that the survivorship of the BHR when used in the target demographic is comparable with that of primary conventional THA, but comparing survivorship of the most durable hip resurfacing arthroplasty device to the survivorship of all conventional THA prostheses is not ideal because the THA group comprises a large number of different types of prostheses that have considerable variation in prosthesis survival. A more informative comparison would be with the THA implants with the best survivorship, as this might help address the question of whether survivorship in the BHR target population can be improved by using a well-performing conventional THA.

QUESTIONS/PURPOSES

We compared the difference in cumulative percent revision, reasons for revision and types of revision for procedures reported to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) using the BHR prosthesis (femoral-head size > 50 mm) and three conventional THA prostheses identified as having the lowest 10-year cumulative percent revision in the currently recommended BHR target population to ask: (1) Does the BHR have a lower cumulative revision rate than the group of three conventional THA prostheses? (2) Is there a difference in the revision diagnosis between the BHR and the three best conventional THA prostheses? (3) What is the difference in the components used for a revision of a BHR compared with the three best conventional THA prostheses?

METHODS

Data reported to the AOANJRR between September 1, 1999 and December 31, 2018 was used for this analysis. This study period includes almost the entire use of the BHR in Australia. The AOANJRR is a large national joint registry with almost 100% completeness, high accuracy, rigorous validation, and little to no loss to follow-up. The study population included males younger than 65 years that had received one hip replacement procedure for osteoarthritis. All patients with bilateral procedures, no matter the time interval between hips, were excluded. Only BHR prostheses with a femoral-head size ≥ 50 mm and conventional THA prostheses with femoral head sizes ≥ 32 mm and either ceramic-on-ceramic or metal, ceramic, ceramicized metal-on-crosslinked polyethylene (XLPE) bearings were included. These femoral head sizes and bearings were selected because they reflect modern conventional THA practice. There is no difference in the revision rate of these bearings in the AOANJRR. There were 4790 BHR procedures and 2696 conventional THA procedures in the study group. The mean (± SD) age for BHR procedures was 52 ± 7.8 years and 56 ± 7.1 years for conventional THA procedures. All comparative analyses were adjusted for age. Other demographics data including American Society Anesthesiologists (ASA) score and BMI were only included in AOANJRR data collection since 2012 and 2015, respectively, and have not been included in this analysis because of the low use of BHR in Australia since that time. The maximum follow-up was 18.7 years for both groups and mean follow-up of 11.9 years for the BHR and 9.3 years for the conventional THA group. Revision rates were determined using Kaplan-Meier estimates of survivorship to describe the time to the first revision, with censoring at the time of death or closure of the database at the time of analysis. A revision was defined as removal, replacement or addition of any component of a joint replacement. Revisions can be further classified as major revisions (removal of a component articulating with bone-usually the stem and/or the shell) or minor revisions (removal of other components-usually the head and/or the liner). The unadjusted cumulative percent revision after the primary arthroplasty (with 95% confidence intervals) was calculated and compared using Cox proportional hazard models adjusted for age.

RESULTS

The BHR prosthesis had a statistically higher rate of all-cause revision at 17 years than the selected conventional THA prostheses (HR 2.77 [95% CI 1.78 to 4.32]; p < 0.001). The revision diagnoses differed between the groups, with the BHR demonstrating a higher revision rate for loosening after 2 years than the conventional THA protheses (HR 4.64 [95% CI 1.66 to 12.97]; p = 0.003), as well as a higher fracture rate during the entire period (HR 2.57 [95% CI 1.24 to 5.33]; p = 0.01). There was a lower revision rate for infection for the BHR compared with the THA group in the first 5 years, with no difference between the two groups after this time. All revisions of the BHR were major revisions (such as, removal or exchange of the femoral and/or acetabular components) and this occurred in 4.5% of the primary BHR procedures. Major revision was the most common type of revision for primary THA accounting for 1.7% of all primary THA procedures. Minor revisions (head, inset or both) were undertaken in a further 0.6% of primary THA procedures.

CONCLUSIONS

Given the increasing revision risk of the BHR compared with better-performing conventional THA prostheses in the target population, we recommend that patients be counseled about this risk. We suggest that a THA with proven low revision rates might be the better choice, particularly for patients who are concerned about implant durability. Well-controlled prospective studies that show appreciable clinically important differences in patient-reported outcomes and functional results favoring the BHR over conventional THA prostheses using modern bearings are needed to justify the use of the BHR in view of this revision risk.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Total Hip Arthroplasty for the Sequelae of Femoral Neck Fractures in the Pediatric Patient

Although rare, total hip arthroplasty (THA) may be indicated in pediatric patients with degenerative changes of the hip joint after previous trauma. To illustrate management principles in this patient population, this study describes the case of a 15-year-old female who sustained bilateral femoral neck fractures after a generalized tonic-clonic seizure, an atypical, low-energy mechanism for this injury. These fractures were not diagnosed until 14 weeks after the seizure episode, at which point they had progressed to nonunion on the left side, malunion on the right side, and degenerative hip joint changes were developing bilaterally. Bilateral THA was ultimately performed, and the patient had favorable outcomes at 1 year postoperatively. In determining the optimal management strategy for such patients, a multidisciplinary approach should be used, with input from the patient’s family, pediatrician, pediatric endocrinologist, pediatric orthopaedic surgeon, and adult reconstruction surgeon. From a surgical standpoint, this report highlights the importance of selecting the appropriate bearing surfaces, broaching technique, mode of implant fixation, and implant features when performing THA in the active pediatric patient.

Influence of total hip arthroplasty and physicians advices in the sports activity performed after the surgery

BACKGROUND AND OBJECTIVES

There are no randomized prospective studies that evaluate sports activity after total hip arthroplasty (THA). The objective of this study is to assess the level and type of sports activity in patients undergoing THA and to assess the recommendations given by physicians.

MATERIALS AND METHODS

We performed a descriptive study that analyzes 46 patients (the average age was 41 years, range 37 - 48) under 50 years of age who underwent THA (58 hips) in our center. The average follow-up was 7.5 (1 - 11) years. Age, sex, sports activity according to the UCLA scale, sports activities practiced before and after the intervention, complications and recommendations given by doctors were evaluated.

RESULTS

The average time to resume sport activity after the surgery was 5 (3-10) months. There were no differences in the UCLA scale before and after the operation (P> 0.05). The most practiced sport before the surgery was swimming (17%). The 31% of patients did not receive advice from their physician and the 65.2% were dissuaded from playing sports after ATC. The recommended sports were swimming (44%) and the static bicycle (17.5%), correlating with the most practiced sports after the operation.

CONCLUSION

The patients modified their sport activity after having undergone a total hip arthroplasty. The surgery and the physician's advice were the ones that influenced the choice of the sports activity performed after being operated on.

The outcome and survival of metal-on-metal hip resurfacing in patients aged less than 50 years

Aims

The aim of this study was to report the implant survival and patient-reported outcome measures (PROMs) in a consecutive series of patients aged less than 50 years at the time of arthroplasty using the Birmingham Hip Resurfacing system (BHR), with a minimum follow-up of ten years.

Patients and Methods

A total of 226 patients with osteoarthritis of the hip, who underwent BHR and presented to a single surgeon, were included in the study. Survival of the implant was confirmed by cross-checking with the Australian Orthopaedic Association National Joint Replacement Registry. Kaplan–Meier survival curves with 95% confidence intervals (CIs) were constructed. Pre- and postoperative PROMs were compared with t-tests, and postoperative scores were compared using anchor analysis with age and gender matched normative data.

Results

At median follow-up of 12 years (interquartile range (IQR) 10 to 13), six BHRs were revised, with a cumulative rate of survival of 96.8% (95% confidence interval (CI) 94.2 to 99.4) at 15 years, and with a significantly lower (p = 0.019) cumulative rate of revision than the national average for the same device at ten years. Most revisions (n = 4) were undertaken early, less than three years postoperatively, and occurred in women. Patient-reported general health (Veteran’s Rand-36), disease state (Western Ontario and McMaster Universities Osteoarthritis Index), function (modified Harris Hip Score) and level of activity (Tegner activity score) maintained significant (p < 0.01 for each) improvements beyond ten years postoperatively and were equal to, or exceeded, age- and gender-matched normative data in more than 80% of the patients.

Conclusion

Longer term PROMs after BHR, from a single surgeon, for patients aged less than 50 years remain under-reported. We found that the outcome after a BHR, at a minimum of ten years postoperatively, remained satisfactory, particularly for self-reported hip function.

Five to Ten-Year Results of the Birmingham Hip Resurfacing Implant in the U.S.: A Single Institution's Experience

BACKGROUND

International surgeon series and registry data have demonstrated positive outcomes and long-term survival of the Birmingham Hip Resurfacing (BHR) implant. We report the 5 to 10-year results from a single center in the U.S.

METHODS

Three hundred and fourteen patients (360 hips) underwent surface replacement arthroplasty with use of the BHR implant and consented to study participation. Patient-reported outcomes and complication and revision data were collected at a minimum of 5 years of follow-up for 93% (324 of 350) of the hips in surviving patients. A matched-cohort analysis was used to compare clinical outcomes between use of the BHR and total hip arthroplasty.

RESULTS

Mean modified Harris hip score (mHHS) and University of California, Los Angeles (UCLA) scores significantly improved postoperatively, to 89.9 and 8.0, respectively (p < 0.001). The Kaplan-Meier estimated rate of survival for all-cause revision was 97.2% (95% confidence interval [CI], 94.7% to 98.5%) and 93.8% (95% CI, 88.8% to 96.7%) at 5 and 10 years, respectively. In a subgroup analysis of patients fitting our current BHR inclusion criteria (males <60 years of age with a diagnosis of osteoarthritis and anatomy conducive to a femoral head component of ≥48 mm), survival free of aseptic revision was 99.5% (95% CI, 96.6% to 99.9%) at 5 years and 98.2% (95% CI, 94.4% to 99.4%) at 10 years. Fourteen patients (4.3% of all hips) required revision. Postoperative UCLA scores were significantly greater for BHR compared with total hip arthroplasty (mean score of 8.0 ± 2.0 versus 7.6 ± 1.8; p = 0.040) in a matched-cohort analysis, with patients matched according to preoperative UCLA score, diagnosis, age, sex, and body mass index. Among matched patients who were highly active preoperatively (UCLA score of 9 to 10), BHR provided a smaller median decrease in the postoperative UCLA score (0.0 versus 1.0; p < 0.001), which was clinically important according to the minimal clinically important difference (MCID, 0.92). Furthermore, BHR provided a greater likelihood of remaining highly active compared with total hip arthroplasty (61% compared with 20%; p < 0.001).

CONCLUSIONS

BHR demonstrated excellent survivorship and clinical outcomes at 5 to 10 years in selected patients. As compared with total hip arthroplasty, the use of the BHR may provide highly active patients with clinically important advantages in postoperative activity as well as a greater likelihood of remaining highly active. Continued follow-up is necessary to validate long-term BHR outcomes.

LEVEL OF EVIDENCE

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

Pleomorphic clinical spectrum of metallosis in total hip arthroplasty

PURPOSE

To summarize the biological effects of metal debris from hip arthroplasties which characterize a polymorphic clinical spectrum of local and remote manifestation.

METHODS

Retrospective study. Patient, implant, and surgical characteristics were collected, including implant survival, clinical manifestations, cause of arthroplasty revision or implant failure, and peri- and intra-operative complications. The primary endpoint was implant survivorship. Hip revision arthroplasty was decided considering clinical signs and symptoms, abnormal imaging (XR, MR, TC, echotomography, scintigraphy), and blood metal ion level. An ad hoc electronic form was used to collect demographic, epidemiological, and clinical variables. In-between group comparisons of quantitative variables were performed with the Student t test and the Mann-Whitney for parametric and non-parametric variables, respectively. Logistic regression analyses were carried out to assess the relationship between clinical and radiographic characteristics and stem and cup revision. Radiographic measurements of implant positioning validity and reliability were assessed using Krippendorff's alpha reliability coefficient. The statistical software STATA version 15 (StatsCorp, TX) was used to perform statistical computations.

RESULTS

In this MoM THA series, the most incident cause of implant failure was ARMD in 11 out of 14 (78.6%) patients. All clinical failure manifestations, revision surgery highlights, and intra-operative findings are reported.

CONCLUSIONS

The local adverse reactions include lesions of different clinical relevance from small asymptomatic soft tissue lesions to dramatic osteolysis, necrosis, effusion, and growing masses which can cause secondary pathological effects. Symptoms of systemic toxicity are rarely described but may have been largely unreported in literature. Despite the extensive literature on the topic, the patient's management is still uncertain and challenging. Every metallic implant (e.g., screws, plates, spinal instrumentations) has a potential local or systemic adverse effect. Organizing a national registry of arthroplasty should be mandatory, in order to collect data about the patients, the surgery, the implanted device (with a careful post-marketing tracking), and the follow-up for all the procedures performed at a national level. The data collected in the registry will allow to analyze the implant survival and to better recognize the undesirable and sometimes unexpected effects of different biomaterials on the whole body.

Hip resurfacing before 50years of age: A prospective study of 979 hips with a mean follow-up of 5.1years

BACKGROUND

Hip resurfacing arthroplasty (HRA) is an alternative to total hip arthroplasty (THA) for the treatment of hip osteoarthritis in patients younger than 50 years. Data on revision rates after HRA are conflicting. The National Institute for Health and Care Excellence (NICE) recommends performing only those hip arthroplasty procedures associated with 10-year revision rates no greater than 5% (0.5% per year). Follow-up studies can rapidly determine whether this criterion is met. The uncertainties surrounding revision rates after HRA prompted us to design a study of prospectively enrolled patients aiming (1) to determine the revision rate after HRA performed before 50years of age and (2) to assess the functional, radiological, and biological outcomes of HRA.

HYPOTHESIS

The revision rate after HRA performed before 50years of age meets the NICE criterion.

MATERIAL AND METHODS

Consecutive patients undergoing HRA before 50years of age were enrolled prospectively. The same implant was used in all patients. Functional outcomes were assessed based on the Harris Hip Score (HHS), Postel-Merle d'Aubigné (PMA) score, 12-item Oxford Hip Score (OHS), and UCLA activity score. Radiographic outcomes were assessed, and blood levels of chromium and cobalt were assayed.

RESULTS

The study included 936 patients (979 HRAs) with a mean age of 42.7years (16.4-50.0years) at surgery and a mean follow-up of 5.1years (range: 3.1-9.0 years). All four mean functional scores were significantly improved at last follow-up vs. baseline: HHS, 95.9 (39.0-100) vs. 44.3 (18.0-83.0); PMA score, 17.6 (6.0-18.0) vs. 11.7 (3.0-16.0); OHS, 14.3 (12.0-37.0) vs. 40.6 (25.0-60.0); and UCLA activity score, 7.8 (2.0-10.0) vs. 5.6 (1.0-10.0) (p<0.0001). Mean cup inclination in the coronal plane was 42.1° (25.0°-68.0°). Mean blood cobalt level was significantly higher at last follow-up than at baseline (1.36μg/L [0.05-8.2μg/L] vs. 0.61μg/L [0.01-3.6]) (p<0.001). No patient experienced dislocation. Revision was required for 17 hips and involved changing the implant in 12 (1.2%). The 10-year survival rate with implant change, as the endpoint was 98.7% (95%CI, 97.6%-99.3%), indicating that the NICE criterion was easily met.

DISCUSSION

The NICE criterion allows the rapid identification of prostheses with insufficient survival. HRA is theoretically associated with a high risk of aseptic mechanical loosening, as it is performed in young patients who have a high level of physical activity. Nevertheless, our study showed that implant survival after HRA was better than required by the NICE criterion. Thus, HRA is a valid alterative to THA in patients younger than 50years.

LEVEL OF EVIDENCE

IV, prospective study with no control group.

Surgical Site Infections Following Birmingham Hip Resurfacing

The Birmingham Hip Resurfacing procedure (BHR) is metal-on-metal resurfacing procedure for hip arthritis. BHR was associated with low risk of surgical site infection (SSI; 0.6%). In addition to antimicrobials, superficial SSIs were treated with incision and drainage, whereas deep incisional or organ-space SSIs required removal of prosthesis. Infect Control Hosp Epidemiol 2016;1-4.

Hip resurfacing arthroplasty for patients with inflammatory arthritis: a systematic review

INTRODUCTION

Modern metal-on-metal hip resurfacing arthroplasty has led to decreased revision rates and high implant survival rates as compared to prior generations of resurfacing. Many of the series that report on resurfacing outcomes focus upon patients treated with a diagnosis of osteoarthritis. Patients with inflammatory arthritis such as rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are also treated in these series, however, their outcomes following resurfacing are underreported. The aim of this study was to determine complications that may occur following hip resurfacing in patients with inflammatory arthritis. A secondary aim was to determine functional outcomes following resurfacing.

METHODS

A search was performed in MEDLINE (PubMed/OVID), Cochrane Library, and Google Scholar. 5 studies met eligibility criteria. This review includes 196 hips; 120 had a diagnosis of AS or seronegative spondyloarthropathy and 76 had a diagnosis of RA or juvenile RA. 8 revisions were reported at a mean time of 64.2 (8.67-275.58) weeks.

RESULTS

Femoral neck fracture was the most common indication for revision, occurring in 3.06% of all hips at 34.5 weeks (16.0-52.0). 2 infections, 2 reports of acetabular radiolucency, and no dislocations were reported. The University of California at Los Angeles score, Harris Hip Score, and Range of Motion were the most common functional outcomes measured, which increased in the majority of studies following resurfacing.

CONCLUSIONS

Femoral neck fracture was the most common reason for revision in patients with inflammatory arthritis following resurfacing and there were no dislocations reported. Following resurfacing, these patients have improved functional outcomes.

Biological effects of metal degradation in hip arthroplasties

Metals and metal alloys are the most used materials in orthopedic implants. The focus is on total hip arthroplasty (THA) that, though well tolerated, may be associated with local and remote adverse effects in the medium-long term. This review aims to summarize data on the biological consequences of the metal implant degradation that have been attributed predominantly to metal-on-metal (MoM) THA. Local responses to metals consist of a broad clinical spectrum ranging from small asymptomatic tissue lesions to severe destruction of bone and soft tissues, which are designated as metallosis, adverse reactions to metal debris (ARMD), aseptic lymphocytic vasculitis associated lesion (ALVAL), and pseudotumors. In addition, the dissemination of metal particles and ions throughout the body has been associated with systemic adverse effects, including organ toxicity, cancerogenesis, teratogenicity, and immunotoxicity. As proved by the multitude of studies in this field, metal degradation may increase safety issues associated with THA, especially with MoM hip systems. Data collection regarding local, systemic and long-term effects plays an essential role to better define any safety risks and to generate scientifically based recommendations.

Long-term results of Birmingham hip resurfacing arthroplasty in Asian patients

Several reports have shown good long-term results with the Birmingham hip resurfacing (BHR) arthroplasty, but little is known about the results in Asian countries where there is a high prevalence of osteonecrosis and developmental dysplasia of the hip, and many females with small femoral head sizes. Therefore, we retrospectively evaluated the long-term clinical results of the BHR in 112 Japanese patients (53 males and 59 females-130 hips) with an average age of 52 years. Implant survivorship was analyzed using the Kaplan-Meier method with the endpoint being revision for any reason. Factors such as sex, femoral component size, and type of hip disease were analyzed as predictors of implant survivorship. With a median follow-up of 12 years, six cases were revised (two for femoral component aseptic loosening, two for infection, one for cup aseptic loosening, and one for femoral neck fracture), and the overall survival rate was 96.5% (95% CI 90.9-98.7) at 10 years and 93.6% (95% CI 83.4-97.7) at 15 years. When septic revisions were excluded, the implant survival rate was 98.2% (95% CI 92.9-99.6) at 10 years and 95.3% (95% CI 83.9-98.7) at 15 years. Sex, femoral component size, and type of hip disease were not predictors of implant survivorship. In conclusion, good clinical results were obtained with the BHR at 10- and 15-year follow-up in Japanese patients who have different stature and types of hip diseases as compared with patients in Western countries.

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.

Clinical and radiographic outcomes of the Birmingham Hip Resurfacing arthroplasty at a minimum follow-up of 10 years: results from an independent centre

BACKGROUND

Metal-on-metal hip resurfacing (MoMHR) has been proposed as an effective surgical treatment for young and active patients with symptomatic hip disease. Recently, good clinical and radiographic outcomes have been reported by the designer surgeons at a 15.3 years follow-up; however, results at long follow-up by non-designer surgeons are less satisfactory. The aim of the study was to investigate if MoMHR can produce satisfactory clinical and radiographic results and if survival rate can be high even if the procedure is performed by non-designer surgeons.

METHODS

All patients were assessed about implant survival. All patients completed an Oxford Hip Score (OHS), Harris Hip Score (HHS) and a University of California Los Angeles (UCLA) activity score preoperatively, at 1 year and at last available follow-up; at this time, a standard anteroposterior weight-bearing radiograph was performed.

RESULTS

The survival rate with revision for any reason is 96%, similar to those obtained by designer surgeons. All the clinical scores improved over time: according to the OHS the survivors are asymptomatic and according to the UCLA maintain a high level of function. 6 remodellings of the femoral neck and 2 heterotopic bone formations were seen, but they were asymptomatic.

CONCLUSIONS

As designer surgeons have already shown, MoMHR can provide in active patients a durable treatment for hip arthritis, with low risk of revision and good results at 10 years follow-up, even if the procedure is performed by non-designer surgeons.

Cobalt serum levels differ in well functioning Birmingham resurfacing and Birmingham modular THA

INTRODUCTION

Metal-on-metal (MoM) bearings are known to release metal ions secondary to wear and corrosion. This may cause local reactions (adverse soft tissue reactions and osteolysis) and systemic effects. Little is known about the exact pattern and the differences between large head MoM total hip replacements (THA) and resurfacings (HR).

QUESTIONS

(1) Is there a difference in metal ion concentrations between HR and MoM-THR using the same bearing design (Birmingham Hip Resurfacing System, Smith & Nephew, Inc. Memphis, TN, USA)? (2) Are metal ion levels changing over time in MoM-THA or HR? (3) Do acetabular inclination angle and femoral component size influence cobalt and chromium levels? Is there a correlation between clinical outcome and metal ion levels?

MATERIALS AND METHODS

A retrospective analysis was conducted in 77 well functioning unilateral Birmingham HR and 42 well functioning unilateral modular Birmingham MoM-THA (Smith & Nephew, Inc. Memphis, TN, USA) operated on between 2007 and 2012. Blood samples were taken at a minimum of 13 months and subsequent during annual follow-ups.

RESULTS

(1) Cobalt levels were significantly higher in MoM-THA compared to HR (p < 0.001). There was no significant difference in chromium levels (p = 0.313). (2) Cobalt is increasing over time in MoM-THA (p = 0.030) whereas metal ions remain stable in HR. (3) Metal ion levels were not affected by acetabular inclination angle and femoral component size in MoM-THA. Chromium levels correlate with the femoral component size (r = -0.240; p = 0.037), the UCLA activity score (r = -0.344; p = 0.003) and the VAS (r = 0.263; p = 0.38) in HR.

CONCLUSION

Considering that HR and MoM-THA used the same MoM bearing design, increased cobalt levels may be related to trunnion wear or corrosion. Elevated cobalt levels should raise concern for corrosion related failure in MoM-THA.

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.

The Role of Hip Arthroscopy in Investigating and Managing the Painful Hip Resurfacing Arthroplasty

PURPOSE

To determine the safety and efficacy of hip arthroscopy performed in the peripheral compartment as a diagnostic and therapeutic treatment option for patients with hip pain after hip resurfacing surgery.

METHODS

Indications for hip arthroscopy after hip resurfacing included patients with a symptomatic hip-resurfaced arthroplasties who did not respond to nonoperative treatment. Patients who underwent a hip arthroscopy after a painful hip resurfacing were included with a minimum of 1 year follow-up. Subgroup analysis was performed according to whether an established diagnosis was made before arthroscopic intervention or not. Subjective measures were based on Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, and results were calculated and analyzed.

RESULTS

We included 68 patients (26 male [38%] and 42 female [62%]) who underwent subsequent hip arthroscopy from a population of 978 consecutive hip-resurfaced arthroplasties performed between 1999 and 2010. The average age was 58 (range, 37 to 78 years). The mean follow-up after hip arthroscopy was 3.4 years (range, 12 months to 5.8 years). Patients who had an established diagnosis (n = 41) before hip arthroscopy showed statistical improvement in their WOMAC scores (7 to 2, P < .001). Only 3 (7%) of these 41 patients failed and were converted to a total hip replacement (THR); however, patients who did not have an established diagnosis (n = 27) before undergoing hip arthroscopy showed statistical worsening of the WOMAC (15 to 21, P = .002). Ten (37%) of these 27 patients without a diagnosis failed and needed to be converted to a THR. A significant correlation was found between the collections found on ultrasound (psoas bursa and/or in the hip joint) and the need for synovectomy (P = .01). The overall revision rate to THR after hip resurfacing in our group of patients was 1.3% (n = 13). Female patients were more likely to require postresurfacing hip arthroscopy with 42 (60%) female to only 26 (40%) male patients undergoing this procedure. In our study population, 70% (14/21, P < .05) of patients with hip pain caused by severe metal synovial reaction or metal-on-metal reaction were women. A total of 5 (7%) patients had minor-to-mild complications after hip arthroscopy.

CONCLUSIONS

Hip arthroscopy is a safe surgical treatment option for those patients with a painful hip resurfacing arthroplasty. Having an accurate diagnosis before hip arthroscopy improves the likelihood a good outcome.

LEVEL OF EVIDENCE

Level IV - therapeutic case series.