Birmingham Hip Resurfacing Arthroplasty Research Articles

Metal levels and glomerular filtration rate after unilateral Birmingham Hip Resurfacing.

The first aim of this study was to evaluate whether preoperative renal function is associated with postoperative changes in whole blood levels of metal ions in patients who have undergone a Birmingham Hip Resurfacing (BHR) arthroplasty with a metal-on-metal bearing. The second aim was to evaluate whether exposure to increased cobalt (Co) and chromium (Cr) levels for ten years adversely affected renal function. As part of a multicentre, prospective post-approval study, whole blood samples were sent to a single specialized laboratory to determine Co and Cr levels, and the estimated glomerular filtration rate (eGFR). The study included patients with 117 unrevised unilateral BHRs. There were 36 females (31%). The mean age of the patients at the time of surgery of 51.3 years (SD 6.5), and they all had preoperative one-, four-, five-, and ten-year laboratory data. The mean follow-up was 10.1 years (SD 0.2). Median Co levels at one year postoperatively increased significantly compared with the preoperative values, by a factor of 9.7, from 0.13 to 1.26 ppb (p < 0.001), and the median Cr levels increased significantly by a factor of 2.5, from 0.60 to 1.50 ppb (p < 0.001). Lower preoperative eGFRs were associated with significantly larger increases in Co at one year compared with the preoperative levels (ρ = -0.26; p = 0.005), but there was no relationship between preoperative eGFRs and changes in Cr at one year (ρ = -0.13; p = 0.153). Metal levels remained relatively constant with the passage of time, with a median ten-year value of 1.12 ppb for Co and 1.29 ppb for Cr. There was no significant relationship between the Co and Cr levels at ten-year follow-up and the change in eGFR from the preoperative level to that at ten years (ρ = -0.02; p = 0.827 for Co; ρ = -0.008; p = 0.933 for Cr). Although patients with lower preoperative eGFRs tended to have larger increases in Co levels at one year, increased metal levels for patients who underwent unilateral BHR did not adversely affect renal function during the first ten postoperative years.

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

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

Birmingham Hip Resurfacing at 20 years.

The Birmingham Hip Resurfacing (BHR) arthroplasty has been used as a surgical treatment of coxarthrosis since 1997. We present 20-year results of 234 consecutive BHRs performed in our unit. Between 1999 and 2001, there were 217 patients: 142 males (65.4%), mean age 52 years (18 to 68) who had 234 implants (17 bilateral). They had patient-reported outcome measures collected, imaging (radiograph and ultrasound), and serum metal ion assessment. Survivorship analysis was performed using Kaplan-Meier estimates. Revision for any cause was considered as an endpoint for the analysis. Mean follow-up was 20.9 years (19.3 to 22.4). Registry data revealed that 19 hips (8.1%) had been revised and 26 patients (12%) had died from causes unrelated to the BHR. Among the remaining 189 hips, 61% were available for clinical follow-up at 20 years (n = 115) and 70% of patients had biochemical follow-up (n = 132). The cumulative implant survival rate at 20 years for male patients was 96.5% (95% confidence interval (CI) 93.5 to 99.6), and for female patients 87% (95% CI 79.7 to 94.9). The difference was statistically significant (p = 0.029). The mean Oxford Hip Score, Hip disability and Osteoarthritis Outcome Score, and Forgotten Joint Score were 45 (29 to 48), 89 (43 to 100), and 84 (19 to 100), respectively. The mean scores for each of the five domains of the EuroQol five-dimension three-level questionnaire were 1.2, 1.0, 1.2, 1.3, and 1.1, and mean overall score 82.6 (50 to 100). Ultrasound showed no pseudotumour. Mean cobalt and chromium levels were 32.1 nmol/l (1 to 374) and 45.5 nmol/l (9 to 408), respectively. This study shows that BHRs provide excellent survivorship and functional outcomes in young male patients. At 20 years, soft-tissue imaging and serum metal ion studies suggest that a metal-on-metal resurfacing implant can be well tolerated in a group of young patients.

Direct Anterior Birmingham Hip Resurfacing: Surgical Technique

Birmingham hip resurfacing (BHR) arthroplasty is an established alternative to total hip arthroplasty for end-stage osteoarthritis, specifically in the younger male patient population who wish to return to high-performance physical activity. Traditionally, this procedure has been performed via the posterolateral approach mainly due to the design of intraoperative equipment utilized for femoral component placement. In other words, no current intraoperative equipment has been designed to perform the BHR via any approach other than the posterolateral approach. Recent literature has shown numerous advantages to direct anterior approach arthroplasty, among total hip arthroplasty patients, such as shorter recovery times, less pain, and improved overall functional outcomes. This technique paper aims to highlight a step-by-step approach of achieving the benefits of direct anterior approach arthroplasty in the patients indicated for BHR. A novel guide-pin technique has been developed to account for lack of intraoperative equipment, with pearls and pitfalls explained in detail. We hope this technique will help to guide surgeons in performing the direct anterior BHR with safety and success thereby maximizing patient outcomes.

Birmingham hip resurfacing: Short term results

Aim: Hip joint replacement provides a dramatic improvement in the quality of life of patients with hip arthrosis but this effect has not been fully achieved in young patients because of early failure with total hip arthroplasty with high activity level. A bone mass protective procedure such as hip resurfacing arthroplasty might be advantageous in young patients. Many options for hip resurfacing prosthesis are available. One of the most used is the Birmingham hip resurfacing prosthesis. The purpose of this investigation compared retrospectively the functional, clinical and radiological outcomes of patients who underwent Birmingham hip resurfacing arthroplasty by a single surgeon for various hip arthrosis.Materials and Methods: Twenty-six hips of 22 patients (12 male, 10 female) were evaluated by using Harris hip score preoperatively and postoperatively. Anteroposterior, lateral and cross-table lateral radiographs of the pelvis and hips were evaluated with respect to component position, migration, and radiolucency postoperatively and at every follow up. Acetabular inclination and anteversion angle, implant-femoral shaft angle, varus and valgus positon, pseudotumor formation around the hip were evaluated by radiologist. Blood samples of patients were taken at last follow ups and evaluated for cobalt and chromium levels by using an inductively-coupled plasma mass spectrometer. Results: Postoperative Harris hip scorewas found to be significantly higher than preoperative Harris hip score. Correlation between chromium ion and size of femoral component, cobalt ion and cup anteversion angle had inverse relationship. There was significant correlation between cobalt ion and gender; females had higher levels of cobalt ion than males.Conclusion: In order to avoid ion load in Birmingham hip resurfacing, caution in selection of patients, avoidance of the use of small components, and attention to the surgical technique to ensure proper placement of the component angles are crucial.

Proximal Femoral Nailing for Intertrochanteric Fracture in Birmingham Hip Resurfacing Arthroplasty

Neck of femur fractures in elderly patients with hip resurfacing in situ are rarely reported injuries. We report a case of intertrochanteric fracture in a 62 year old man with ipsilateral Birmingham Hip Resurfacing (BHR) arthroplasty, successfully treated with internal fixation using proximal femoral nail. There were no intraoperative or postoperative complications and the patient returned to his normal level of activities within 6 months after the fixation. In conclusion we have demonstrated that fixation with proximal femoral nails can be an alternative safer option in treatment of these complex injuries.

Short and mid-term outcomes and functional results in metal-on-metal hip resurfacing arthroplasty at 5 years follow-up: the Spanish experience

BackgroundHip resurfacing arthroplasty (HRA) and in particular, Birmingham hip resurfacing (BHR), is commonly employed as an alternative to total hip arthroplasty (THA) in young patients, as it allows for preservation of femoral bone stock and resumption of physical activity. The aim of our study was to investigate 5-year survival and functional outcomes of BHR arthroplasty in young Spanish osteoarthritis (OA) patients.MethodsThis is an observational, prospective, cohort study of patients who underwent BHR between June 2005 and December 2009 at a Spanish public hospital with a minimum follow-up of 5 years. All surgeries were performed by a single surgeon (RLM). Survival was analyzed using the Kaplan-Meier method. Functional outcomes and return to work and physical activities were also assessed.ResultsFive-year survival rate of the prosthesis was 95.74% (95% CI: 95.77–98.07), and estimated 10-year survival was 92.92% (95% CI: 85.07–96.72). Harris hip score significantly increased from 41.13 to 97.63 (p < 0.001) at 5-year follow-up. Average time for returning to work and sporting activities was 3.89 (SD: 2.39) and 3.47 (SD: 1.18) months respectively. Failure occurred in 14 patients, 8 of whom experienced femoral neck fractures.ConclusionsOur data support the short and mid-term efficacy of BHR arthroplasty in young OA patients, indicating good implant survival, improvement in patients’ functionality and a swift return to work and physical activities after surgery.

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 52years. 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 12years, 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 10years and 93.6% (95% CI 83.4-97.7) at 15years. When septic revisions were excluded, the implant survival rate was 98.2% (95% CI 92.9-99.6) at 10years and 95.3% (95% CI 83.9-98.7) at 15years. 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 vs Total Hip Arthroplasty: A Matched-Pair Comparison of Clinical Outcomes

BackgroundBirmingham hip resurfacing (BHR) has proven to be a good alternative for younger patients with osteoarthritis. Some have asserted that BHR may yield outcomes which are superior to total hip arthroplasty (THA), and that some studies which failed to show a difference were plagued by ceiling effects and lack of sensitivity of outcome measures. The purpose of this study is to compare outcomes of BHR and THA using the “Forgotten Joint” Score-12 (FJS), a more sensitive score with lesser vulnerability to the ceiling effect. MethodsPatients who underwent BHR were matched to patients who underwent posterior THA by computing a propensity score using 5 covariates: age, body mass index, gender, worker's compensation claims, and previous hip surgery. Surgical outcomes were assessed using 6 patient-reported outcome measures, including the FJS, the visual analog scale for pain, and patient satisfaction. ResultsThere were 42 patients in the BHR group and 18 patients in the THA group. The FJS was 78.0 for the BHR group and 76.0 for the THA group. The Veterans RAND 12-Item Health Survey Mental Component Summary and Short Form 12 Mental Component Summary were significantly higher in the BHR group. No differences were seen between all other patient-reported outcomes. ConclusionBHR offers excellent results in young patients that are comparable to THA. As no clinical difference could be shown between BHR and THA, even with the use of the FJS, the choice between BHR and THA should not be based solely on any expectation that either yields superior clinical outcomes compared to the other at short-term follow-up.

Birmingham hip resurfacing versus cementless total hip arthroplasty in patients 55 years or younger: A minimum five-year follow-up

ObjectiveThe optimal reconstructive method for advanced degenerative hip disease in young adults is a topic of ongoing discussion. The purpose of this study is to report the largest single institution experience from the United States on the outcomes of Birmingham hip resurfacing (BHR) vs. cementless total hip arthroplasty (THA) in patients 55 years or younger at a minimum follow-up of five years. Currently, BHR is the only FDA-approved hip resurfacing implant available in the US. MethodsA cohort of 505 patients representing all BHR cases performed at our institution between 2006 and 2010 was compared with an identical size cohort of consecutive patients who underwent primary cementless THA. Exclusion criteria were age greater than 55 years, non-elective cases, revision procedures, and those performed for fractures, tumors, or by low-volume arthroplasty surgeons. THAs with metal on metal articulation were also excluded. Outcomesassessed were all-cause reoperations, complications, patient satisfaction, and mortality. After exclusions, 442 patients with BHR and 327 with THA were included. ResultsMean follow-up was 73.2 months. After controlling for potential confounding factors, multivariate analyses showed significant increase in the rates of revision surgery (p<0.001), overall complications (p<0.001), all-cause reoperations (p=0.014), and mortality (p<0.001) in the THA cohort. Component loosening was the most common cause for revision in the THA group. Patients with THA were also less likely to be satisfied (p=0.046). ConclusionsThis is largest US study to report on the midterm outcomes of BHR vs. THA. The results demonstrate favorable results for BHR in patients 55 years or younger. Long-term multicenter studies are needed to better understand the optimal patient characteristics when deciding between THA versus BHR.

Return to sporting activity after Birmingham hip resurfacing arthroplasty: Mid term results.

Background:Hip resurfacing arthroplasty (HRA) is primarily indicated for young, active patients with disabling coxarthrosis who wish to remain active and return to sports after surgery. Relatively few prospective studies have assessed return to sporting activity and impact of gender and age on this.Materials and Methods:Seventy-nine consecutive patients treated with HRA were included. Patients were reviewed clinically and radiologically. Function was assessed using the modified University of California Los Angeles (UCLA) activity score. The Oxford, Harris and WOMAC hip scores were calculated.Results:Average age at the time of surgery was 54.9 years (range 34.5–73.6 years). Average preoperative and postoperative UCLA scores were 4 and 7.6 respectively. Patients were involved in 2 (0–4) sporting activities preoperatively and 2 (0–5) postoperatively. Preoperative and postoperative Oxford Hip Scores, Harris Hip Score and WOMAC scores were 40, 46 and 51 and 16, 94 and 3 respectively (P < 0.0001). Patients returned to sports at an average of 3 months postoperatively.Conclusion:Patients were able to return to sports by 3 months and perform the same number of activities at preoperative intensity. Activity levels are maintained up to the medium term with few complications.

Adverse reaction to metal debris after Birmingham hip resurfacing arthroplasty

Background and purpose — Concern has emerged about local soft-tissue reactions after hip resurfacing arthroplasty (HRA). The Birmingham Hip Resurfacing (BHR) was the most commonly used HRA device at our institution. We assessed the prevalence and risk factors for adverse reaction to metal debris (ARMD) with this device.Patients and methods — From 2003 to 2011, BHR was the most commonly used HRA device at our institution, with 249 implantations. We included 32 patients (24 of them men) who were operated with a BHR HRA during the period April 2004 to March 2007 (42 hips; 31 in men). The mean age of the patients was 59 (26–77) years. These patients underwent magnetic resonance imaging (MRI), serum metal ion measurements, the Oxford hip score questionnaire, and physical examination. The prevalence of ARMD was recorded, and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.7 (2.4–8.8) years.Results — 6 patients had a definite ARMD (involving 9 of the 42 hips). 8 other patients (8 hips) had a probable ARMD. Thus, there was definite or probable ARMD in 17 of the 42 hips. 4 of 42 hips were revised for ARMD. Gender, bilateral metal-on-metal hip replacement and head size were not factors associated with ARMD.Interpretation — We found that HRA with the Birmingham Hip Resurfacing may be more dangerous than previously believed. We advise systematic follow-up of these patients using metal ion levels, MRI/ultrasound, and patient-reported outcome measures.

Patient satisfaction and clinical results at a mean eight years following BHR arthroplasty: results from a district general hospital.

We present the clinical and radiological results of a prospective study of a consecutive series of patients treated with the Birmingham Hip Resurfacing (BHR) prosthesis between 1999 and 2006 and followed for six to 12 years. Patients were reviewed preoperatively and six, 12, 26 and 52 weeks postoperatively and annually thereafter. They were assessed clinically and radiographically and the Merle d'Aubigne Postel and Oxford Hip scores were calculated at each visit. A SF-36 form assessed general health. Patient satisfaction was assessed by a Visual Analogue Score. Kaplan Meier survival analysis was performed.One hundred and seven patients (109 hips) were included (45 males, 62 females). Median age was 44 years. Mean follow-up was 97.4 months. Median preoperative Merle d'Aubigne Postel and Oxford hip scores were 10 (3-14) and 42 (26-55) respectively. Median SF36 score was 29 (0-65) and patients rated their level of pain as 7.7 on a scale of 0-10 (10 being the worst score). At final follow-up, median MDP and OHS scores were 17 (16-18) and 25 (12-46). Median SF36 score was 72 (27-97). Seven revisions were performed in six females and one male patient. Survival was 96.2% with revision for any reason as the end point. No revisions were performed in the group with hip dysplasia.The BHR prosthesis provides pain relief, high levels of patient satisfaction and improvement of function and well being in the medium-term. Failures occurred primarily in the female group.

Intramedullary fixation of pertrochanteric fractures after hip resurfacing arthroplasty – Do we have the answer? Case report and literature review

ObjectiveTo report a case of a peri-prosthetic hip fracture fixed using a previously unreported technique of intramedullary nailing with dual proximal fixation. Case summaryAn 81-year-old nursing home resident suffered a multi-fragmentary peri-prosthetic hip fracture around a Birmingham Hip Resurfacing arthroplasty (BHR), which was fixed using a novel technique. DiscussionSuch fractures pose a significant surgical dilemma with regards to the optimal method of treatment. The increasing popularity of these implants suggests that these fractures will become increasingly common. ConclusionWe believe that our technique provides a practical and satisfactory solution to these fractures.

Hip resurfacing arthroplasty versus large-diameter head metal-on-metal total hip arthroplasty: comparison of three Designs from the Finnish Arthroplasty Register

Large headed metal-on-metal total hip arthroplasty may produce more metal ions than hip resurfacing arthroplasty. Increased metal-ion levels may be associated with higher revision rates due to adverse reaction to metal debris. The purpose of our study was to compare the survivorship of three hip resurfacing arthroplasty designs with their analogous cementless large-diameter head metal-on-metal total hip arthroplasties. Based on data obtained from the Finnish Arthroplasty Register, the revision risks of three metal-on-metal hip resurfacing arthroplasty/total hip arthroplasty design couples performed during 2001-2011 were analyzed using the Cox regression model. In the Cox regression analysis for compared design pairs adjusted for age, gender, operated side, head size, diagnosis, and implant, there was no statistically significant difference in revision risk between ReCap hip resurfacing arthroplasty and Bimetric/ReCap total hip arthroplasty (risk ratio = 1.43, confidence interval = 0.95-2.14, p = 0.09) or between Birmingham hip resurfacing arthroplasty and Synergy/Birmingham hip resurfacing total hip arthroplasty (risk ratio = 1.35, confidence interval = 0.75-2.43, p = 0.31). However, the revision risk of Corail and Summit/articular surface replacement total hip arthroplasty (ASR HRA) was significantly increased compared to ASR HRA. (risk ratio = 0.73, confidence interval = 0.54-0.98, p = 0.04). We conclude that the short-term revision risk of large headed metal-on-metal total hip arthroplasties was not increased compared to analogous hip resurfacing arthroplasties in two out of three devices studied at a nationwide level. There may be implant-related factors having an effect on the success of single manufacturer devices. However, more information on the incidence of adverse soft-tissue reactions in these patient cohorts is needed.

Coloarticular Fistula Associated with a Pseudotumor After Metal-on-Metal Hip Resurfacing Arthroplasty: A Case Report.

Fistula formation between the bowel and an implant following hip arthroplasty is rare1-11. Documented predisposing conditions include pelvic radiation therapy, long-term corticosteroid use, pelvic migration of the hip arthroplasty acetabular component, diverticulitis, and Crohn disease2,4-7,9-13. To our knowledge, we report the first known coloarticular fistula associated with a pseudotumor after a metal-on-metal hip resurfacing arthroplasty. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A fifty-nine-year-old woman with a six-week history of pain in the left lower quadrant of the abdomen that radiated to the left groin and thigh presented to our institution. She had no change in bowel habit and no history of febrile illness. The left hip had been painful for about six months. She had undergone a total abdominal hysterectomy and bilateral salpingo-oophorectomy and omentectomy for a left ovarian tumor eighteen months earlier. The histopathology report had revealed a borderline mucinous tumor confined to the left ovary. The history also included right and left Birmingham hip resurfacing (Smith & Nephew, Warwick, United Kingdom) arthroplasty for osteoarthritis, performed nine and five years earlier, respectively. These resurfacing arthroplasties, which were performed at a different institution, had no intraoperative or postoperative complications. On examination, there was a nontender mass in the left iliac fossa. Left hip movement was considerably restricted by pain. A radiograph of the pelvis showed bilateral Birmingham hip resurfacing without evidence of loosening (Fig. 1). A computed tomography (CT) scan of the thorax, abdomen, and pelvis was obtained. This showed a 6 × 7-cm complex heterogeneous mass involving the mid and distal portion of the left psoas muscle (Fig. 2). The left external iliac vein and artery were displaced by this lesion but did …

A Comparison of Two Resurfacing Arthroplasty Implants: Medium-Term Clinical and Radiographic Results

The objective of this study was to perform a medium-term analysis comparing the clinical and radiographic outcomes of the CONSERVE® Plus (C+) and Birmingham Hip Resurfacing (BHR) arthroplasty systems. 137 hips were included in each cohort, with a mean follow-up of 60.0 ± 14.2 months and 63.3 ± 3.5 months in the C+ and BHR cohorts respectively. Latest review UCLA and HHS scores showed statistically significant improvements when compared with preoperative scores for both cohorts. UCLA and SF-12 physical component outcome scores were significantly different (p<0.01 and p = 0.04, respectively). Median serum chromium and cobalt levels were significantly increased in the BHR cohort (p = 0.001). Both cohorts demonstrated excellent Kaplan-Meier 5-year survival rates (96.9% in the C+ cohort, and 96.4% in the BHR cohort). Overall both implants appear to perform well in the medium term.

Femoral Neck Fracture After Birmingham Hip Resurfacing Arthroplasty: Prevalence, Time to Fracture, and Outcome After Revision

A consecutive cohort of 3076 Birmingham Hip Resurfacings from a single institution was analyzed. The prevalence of femoral neck fracture, the time to fracture, and the outcome after revision were investigated. Fractures occurred in 34 hips (prevalence, 1.1%). Median time to fracture was 0.27 year (range, 0.014-11.2 years). Mean operation time for revision was 59 minutes, and 71% underwent isolated femoral component revision. At a mean follow-up of 5.5 years since revision, 3 patients required re-revision (2 aseptic loosening, 1 for sepsis) giving a survival of 95.7% (confidence interval, 86.9%-100%) at 5 years for the revision. Median Oxford Hip Score was 12.5% (interquartile range, 3.2%-32.3%). There were no cases of radiologic failure during follow-up. Most fractures occur early after hip resurfacing and were straightforward to revise.

Revision rate of Birmingham Hip Resurfacing arthroplasty: comparison of published literature and arthroplasty register data

Hip resurfacing arthroplasty has gained popularity for treating young and active patients who have arthritis. There are two major data sources for assessing outcome and revision rate after total joint arthroplasty: sample-based clinical trials and national arthroplasty registers. The purpose of this study was to evaluate the outcome of the Birmingham Hip Resurfacing (BHR) arthroplasty in terms of revision rate as reported in clinical studies and recorded by national arthroplasty registers. A comprehensive literature research was performed from English-language, peer-reviewed journals and annual reports from national joint arthroplasty registers worldwide. Only publications from MEDLINE-listed journals were included. The revision rate was used as the primary outcome parameter. In order to allow for direct comparison of different data sets, calculation was based on revisions per 100 observed component years. For statistical analysis, confidence intervals (CI) were calculated. A total of 18,708 implants, equivalent to 106,565 observed component years, were analysed in the follow-up studies. The register reports contained 9,806 primary cases corresponding to 44,294 observed component years. Statistical analysis revealed a significant difference in revisions per 100 observed component years between the development team (0.27; CI: 0.14-0.40) and register data (0.74; CI: 0.72-0.76). The BHR arthroplasty device shows good results in terms of revision rate in register data as well as in clinical studies. However, the excellent results reported by the development team are not reproducible by other surgeons. Based on the results of our study, we believe that comprehensive national arthroplasty registers are the most suitable tool for assessing hip arthroplasty revision rate.

Two-year migration results of the ReCap hip resurfacing system—a radiostereometric follow-up study of 23 hips

There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, and enhanced implant fixation. In contrast to conventional total hip replacements, only a few clinical hip resurfacing trials using radiostereometry (RSA) have been reported, and solely for the Birmingham hip resurfacing arthroplasty. The purpose of this RSA trial was to describe the migration pattern of a new hip resurfacing system (ReCap) within the first two years after primary surgery. Twenty-six patients underwent total hip replacement. The patients were followed-up for up to 24 months and were evaluated with the use of radiostereometric measurements. The prosthesis showed mean translations and rotation close to zero. Maximum translation was seen along the transverse axis in the medial direction (0.13 mm). No statistically significant translation or rotation was seen at two-years follow-up, (t-test, p <0.05, translation or rotation).