Introduction. Short-stem hip arthroplasty is gaining popularity as a method of treating hip arthritis in biologically younger patients. The potential benefit of using a short-stem is preservation of bone in the proximal femur for a future revision. We have compared the early clinical and radiological results of a short-stem hip arthroplasty versus a conventional total hip arthroplasty (THA) using a standard length femoral prosthesis with particular focus on functional outcome. Methods. We evaluated a prospectively collected data on consecutive series of 249 patients, who underwent uncemented total hip arthroplasty at our institution. They were distributed into 2 groups: Group I, 125 patients received an uncemented short femoral stem (Mini Hip Arthroplasty (MHA), Corin, Cirencester) and Group II, 124 patients received a conventional uncemented femoral stem (Accolade, Stryker, Michigan) with mean follow up of 3.2 years (2–4). The characteristics of the two groups have been presented in Table I. Evaluation was based on plain radiographs performed at 6 months, 1 year and 2 years postoperatively, while their clinical status was assessed using the modified Harris hip score (mHHS) preoperatively and postoperatively at 6 weeks, 6 months, 1-year, 2-years and annually thereafter. Results. The outcome measures and complications in the two groups are presented in Table II. The mHHS was split into their two components (pain and function) to evaluate any differences between the groups. The postoperative results for pain were similar in both groups (p > 0.05), but the functional element of mHHS was significantly better (p < 0.05)* in Group I compared to Group II. This difference however did not reach the level of the minimum clinically important difference. All femoral stems showed radiographic evidence of bony ingrowth. No evidence of stem subsidence was found in any of the patients. One femoral implant was revised for infection in Group II. Conclusion. Our study suggests that the results of short-stem hip arthroplasty are comparable to conventional uncemented THA in the short-term. The functional outcome scores appear to be better in the short-stem group compared to the conventional group, but the difference is not clinically relevant. Short-stem hip arthroplasty can be an optimal choice for use in younger patients with good bone quality, who are expected to require revision in the future

To date, the literature has not yet revealed superiority of Minimally Invasive (MI) approaches over conventional techniques. We performed a systematic review to determine whether minimally invasive approaches are superior to conventional approaches in total hip arthroplasty for (1) clinical and (2) functional outcomes. We performed a meta-analysis of level 1 evidence to determine whether (3) minimally invasive approaches are superior to conventional approaches for clinical outcomes.

All studies comparing MI approaches to conventional approaches were eligible for analysis. The PRISMA guidelines were adhered to throughout this study. Registries were searched using the following MeSH terms: ‘minimally invasive’, ‘muscle-sparing’, ‘THA’, ‘THR’, ‘hip arthroplasty’ and ‘hip replacement’. Locations searched included PubMed, the Cochrane Library, ClinicalTrials.gov, the EU clinical trials register and the International Clinical Trials Registry Platform (World Health Organisation).

Twenty studies were identified. There were 1,282 MI THAs and 1,351 conventional THAs performed.

Intermuscular MI approaches are equivalent to conventional THA approaches when considering all-cause revision, aseptic revision, infection, dislocation, fracture rates and functional outcomes. Meta-analysis of level 1 evidence supports this claim.

Purpose: Surface replacement arthroplasty is being increasingly offered as the treatment of choice to young and active patients with hip arthritis with proposed advantages including bone conservation and better functional outcome. Excellent outcome has been reported in the few recent short-term clinical series of surface replacement arthroplasty. However they have an inbuilt patient selection bias. There are no direct prospective randomized studies comparing the newer generation of surface replacement arthroplasty with conventional total hip arthroplasty. Our study addresses this issue. Method: 210 hips in 194 patients were randomized to receive either an uncemented total hip arthroplasty or a hybrid metal-on-metal surface replacement arthroplasty. Complications, functional outcomes, along with patient satisfaction and radiographic evaluation were compared at a minimum of two years follow up. Results: Patients in both groups demonstrated a very high satisfaction rate and achieved similar functional scores. Four dislocations occurred in the THA group (one needing acetabular cup revision) and none in the SRA group. There were no femoral neck fractures in the surface replacement arthroplasty group. However, two surface replacement arthroplasty cases underwent revision for late head collapse and one needed a femoral neck osteoplasty for persisting femoro-acetabular impingement. Better biomechanical restoration was attained with surface replacement arthroplasty. All the components were considered to be stable after an average follow up of 45 months. Conclusion: Although surface replacement arthroplasty of the hip offer similar patient satisfaction, functional outcome and complication rate as an uncemented total hip arthroplasty in a young and active group of patients, different complications were associated to each procedure. Better patient selection could avoid some of the complications in the surface replacement arthroplasty group. One main advantage that remains for the surface arthroplasty technique it is the proximal femoral bone stock preservation. However, long term survival analysis is necessary to determine the true advantage of these implants over total hip arthroplasty

Introduction

The incorporation of computer navigation in total hip arthroplasty (THA) has been much slower then for total knee arthroplasty (TKA). Computer navigation has proven itself in the realm of TKA but still has yet to advance in THA. The reasons for this include the lack of ease of incorporation, accuracy and precision, and the addition of overall operative time. Another reason for this lack of progress is that a majority of THA's are done with the patient in the lateral position through a posterior or lateral approach making the tracker placement and the registration process somewhat cumbersome. In the direct anterior approach the patient is in the supine position, which accommodates pelvic tracker placement and significantly facilitates the registration process. At our institution we use the direct anterior approach and computer navigation on all of our primary THA's. We hypothesized that computer navigation facilitates cup placement and leg length determination with out significantly increasing our operative time.

In this study we compare survivorship and patient reported outcome measures in robotically assisted versus conventional Total Hip Arthroplasty (THA). This paper investigates the hypothesis that implant survival and PROMS following THAs performed with robotic assistance were not different to outcomes following conventional THAs. Data included all patients undergoing THA for osteoarthritis between 19 April 2016 and 31 December 2020. Analysis of PROMS outcomes was restricted to those who had completed PROMS data preoperatively and at 6 months postoperatively. There were 157,647 procedures, including 3567 robotically assisted procedures, available for comparison of revision rates. 4557 procedures, including 130 robotically assisted procedures, had PROMS data available. The revision rate of primary THA performed with robotic assistance was not statistically different from THA performed by conventional methods (4 year cumulative percent revision 3.1% v 2.7%; HR = 1.05, p=0.67). The Oxford Hip Score, VAS for pain and the EQ-VAS score for overall health showed no statistically significant difference between the groups. The EQ-5D Utility Score showed an improved score (median score 1 v 0.88; OR = 1.58, p=0.007) for the robotically assisted group compared to the conventional group. Robotic assisted THA was not associated with significant improvement in early revision or joint-specific PROMs. The findings may have been biased, in either direction, by unmeasured patient, surgeon, hospital and prosthesis factors. The findings (including the difference in health-related quality of life) may have also been influenced by lack of blinding. Future research should include methods to minimise these biases

In-hospital length of stay (LOS) and discharge disposition following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, we wished to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge disposition following robotic-arm assisted (RO THA) versus conventional technique Total Hip Arthroplasty (CO THA). This large-scale, single institution study included patients of any age undergoing primary THA (N = 1,732) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for Post Anaesthesia Care Unit (PACU) admission, anaesthesia type, readmission within 30 days and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. The median LOS in the RO THA group was 54 hours (34, 78) versus 60 (51, 100) in the CO THA group, p<0.001. Discharge disposition was comparable between the two groups. In the multivariate model, age, need for PACU admission, ASA score > 2, female gender, general anaesthesia and utilisation of the conventional technique were significantly associated with LOS > 2 days. Our study showed that robotic-arm assistance was associated with a shorter LOS in patients undergoing primary THA and no difference in discharge destination. Our results suggest that robotic-arm assistance could be advantageous in partly addressing the upsurge of hip arthroplasty procedures and the concomitant health care burden; however, this needs to be corroborated by long-term cost effectiveness analyses and data from randomised controlled studies

There has been a renewed interest in surface replacement arthroplasty over the last decade, with the hope and expectation that this procedure would provide an advantage over conventional total hip arthroplasty, especially in the young, active patient. More specifically, the promises of surface replacement arthroplasty have been: 1) preservation of bone stock so that future revisions would be easier, 2) potential to be minimally invasive in their approach, 3) better functional outcomes because of the stability associated with a larger femoral head with potential associated proprioceptive advantages, and 4) improved survivorship. Unfortunately, these promises have not been realised. Surface replacement arthroplasty does maintain more initial bone stock on the femur, but also tends to remove more bone initially on the acetabular side. Long term, it is the loss of acetabular bone stock that is more problematic from a reconstructive perspective. Further, the “simple” revision afforded in surface replacement arthroplasty has led to reports of inferior clinical outcomes, especially with respect to subjective complaints of pain. Surface replacement arthroplasty is more invasive than conventional total hip arthroplasty as the femoral head is maintained and the window to the acetabulum is subsequently partially blocked. This is exacerbated by the fact that many of these patients are young active males. There is no compelling evidence that surface replacement arthroplasty offers improved functional outcomes over conventional total hip arthroplasty, particularly when considering gait and proprioception. Some studies have in fact shown inferior outcomes. The concept of the larger femoral head in surface replacement arthroplasty providing increased range of motion and subsequent better function is flawed as it is the head-to-neck ratio that appears to be a more important determinant of outcome in this sense. Total hip arthroplasty generally has a more favorable ratio. Surface replacement arthroplasty has inferior survivorship to conventional total hip arthroplasty, even when accounting for the younger age of this patient cohort. This finding is consistent across multiple national joint replacement registries. The outcomes and survivorship are particularly poor in females, with many authors now advocating that the procedure be reserved for males. Surface replacement arthroplasty has introduced several new problems and mechanisms of failures, most concerning of which is the formation of pseudotumors in some patients. It is unclear as to who is at risk for this significant complication, and the ability to diagnose and treat this disorder is difficult and still in evolution. Likely associated is the significant elevation of metal ions in the serum and urine of some surface replacement arthroplasty patients. Neck fractures and loss of bone stock around the femoral implant have also been noted as problematic for these devices. Some of these problems have led to specific surface replacement arthroplasty systems being recalled. Finally, surface replacement arthroplasties are premium products with associated increased costs, which, frankly, are not justified

Introduction. Hip resurfacing arthroplasty (HRA) lost its popularity because of excessive wear of the ASR M/M design. Now that causes of wear have been identified, it remains an attractive treatment option for young patients because of its bone-conserving nature, the preservation of bone mineral density, a low dislocation rate, and its biomechanical precision. Methods. We assessed the long-term clinical outcomes of 1074 patients (1321 hips) who were implanted with hybrid Conserve. ®. Plus HRA, with 556 surgeries performed in patients younger than 50 years of age (average, 41.6 years) compared to 765 surgeries performed in patients 50 years or older (average, 58.1 years). 74% of the patients were male. There were no exclusion criteria. The <50 group had a larger proportion of dysplasia and hips operated during the first generation of surgical technique. Results. The mean elapse time after surgery was 15.6 years (range 7.4 to 22.5 years). We found no difference in UCLA pain, walking and function scores between the two groups except for a slightly higher activity level in the younger group (7.4 vs. 7.2, p=0.0172). Quality of life SF-12 scores were also comparable. Although we found better survivorship rates for the group of older patients (Log-rank test p=0.0107 – Figure 1) between the younger and older patients (Table 1), this difference was largely explained by the greater proportion of dysplasia (p=0.0001) and 1. st. generation hips (p=0.044) in the <50 group. The rate of post-operative complications (dislocations, sepsis, neve palsies, blood-related and others) was not significantly different between groups (p=0.3738). However, the complication rate dropped significantly (p=0.0390) in both groups from 6.4% for the first and 2. nd. generations of surgical technique (n=670) to 3.8% with the 3. rd. generation of surgical technique (n=651). Conclusions. The long-term results of metal-on-metal HRA meet and even surpass the original expectations in young and active adults, with survivorship rates far superior to those reported in registries for conventional total hip arthroplasty. However, the etiologic characteristics (particulartly hip dysplasia in women of small size, but not osteonecrosis) of this demanding population also affect the results of HRA with a lower survivorship compared with that of older patients. For any tables or figures, please contact the authors directly

We report a rare case of Hip Resurfacing dislocation three years after a bilateral Hip Resurfacing in a very strong patient and show the maneuver to do a closed reduction on a film done at the surgical theatre under general anesthesia. Hip resurfacing dislocation is a very rare entity described in the literature and more rare after three years. With conventional total hip replacement the dislocation rate is 2–5%. In the international literature the dislocation rate with resurfacing is 0.21%. We describe a case of a 47 years old male patient who was submitted to a biltateral 54 × 60 mm Hip Resurfacing in November 16 th and 18th, 2011 (two separate days). He had a normal post op and returned to his work after six weeks and recreational activities after four months. Three years later, on November 8th, 2014 he did an extreme movement of hip flexion, adduction and internal rotation when he was gardening and planting a tree seedling suffering a left hip dislocation. Hopefully we could reduce the dislocated hip in a closed manner in the following morning. Patient went home next day but on that same night had important abominal pain needing to return to hospital when numerous gallbladder stones where found being submitted to a total laparoscopic colecistectomy two days later. It was really a bad luck week. Metal ions are still normal and patient is symptomless until today having returned to his recreational activities. We will show in a movie the maneuver to do this closed reduction and hope by showing this maneuver that our colleagues do not have to do an open dislocation in the future in case they face a Hip Resurfacing dislocation

The purpose of this study is to assess the accuracy of component positioning and incidence of peri-operative and 90-day post-operative complications following robotic arm-assisted and conventional total hip arthroplasty (THA). Three groups of patients were analyzed for this study: those that underwent conventional THA performed by Surgeon 1, conventional THA performed by Surgeon 2, or robotic arm-assisted THA performed by Surgeon 2. All patients underwent primary uncemented THA via a posterior approach. Patient characteristics, intra-operative data, and 90-day post-operative complications were collected. Post-operative standing pelvic radiographs were utilized to measure acetabular position and to identify post-operative complications. Acetabular component position measurements revealed substantially less variation in both inclination and anteversion in the Surgeon 2 – Robotic group. Nine patients had intra-operative cables placed for intra-operative calcar fracture in the Surgeon 1 group compared to one patient and three patients in Surgeon 2 – Robotic and Surgeon 2 – Traditional groups, respectively. Nine instances of femoral stems subsidence were identified in the Surgeon 1 group compared to one patient in Surgeon 2 – Traditional. There were four instances of dislocation in the Surgeon 1 group compared to one in the Surgeon 2 – Robotic group. Robotic arm-assisted THA decreases the variation in acetabular component positioning compared to conventional THA. However, the benefit of this is unclear as there is little difference in dislocation rate. This study may demonstrate additional value in CT-based implant planning as this cohort had the lowest incidence of femoral component complications

Resurfacing arthroplasty is advantageous over conventional total hip arthroplasty in that femoral bone stock is preserved. However, there has been controversy over the preservation of acetabular bone stock in resurfacing arthroplasty, with the concern that it may result in excess reaming compared with total hip replacement. This is of concern as the prosthesis is primarily advocated in the young patient, who is likely to face future revision surgery. We prospectively identified a cohort of 68 patients with primary hip osteoarthritis undergoing conventional total hip arthroplasty. During surgery, the excised femoral head and neck diameter was measured, along with the diameter of the final acetabular reamer used to achieve a bed of bleeding cancellous bone. The measured neck diameter was then used to calculate the minimum possible resurfacing head and cup sizes, with corresponding final reamer sizes that could have been used in each patient without neck notching for both Birmingham Hip Resurfacing (BHR, Smith & Nephew, 3rd Generation) and Articular Surface replacement (ASR, De Puy, 4th Generation). Reaming diameter and volume was compared for all 3 groups. Mean reaming diameters for the THR, ASR and BHR groups were 51, 52 and 56mm respectively. Mean reaming volumes were 39, 40 and 47cc. There was a statistically significant difference between the THR and BHR groups for both reamed diameter and volume (p< 0.001). There was also a significant difference between the ASR and BHR groups for both reamed diameter and volume (p< 0.001). This difference was more pronounced with larger neck diameters. Our data shows that the BHR results in more ace-tabular bone loss compared to total hip replacement. An implant with a lower profile acetabular cup and a larger variety of sizes such as the ASR may allow better preservation of acetabular bone stock

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.

Aims

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings.

Resurfacing total hip replacement using metal on metal bearings is increasing in popularity, but the outcomes are currently unclear. We report a series of 23 hips in 20 patients who underwent resurfacing total hip replacement over a period of 4 years. The mean age at surgery was 47 years (21–61). There were 8 females and 12 male patients. The mean follow up was 27 months (range 6 to 50 months). Before performing this study, our impression was that most outcomes were good but that there appeared to be more variability in pain relief than anticipated after conventional total hip replacement. Most were performed for primary osteoarthritis; other diagnoses included AVN, DDH and multiple epiphyseal dysplasia. Outcomes were measured examining x rays, survival of the implant and the Oxford hip questionnaire. There were no early revisions, but we are aware of one loose acetabular cup (in a patient with DDH) which is asymptomatic but which will probably require revision. There were no femoral neck fractures. The median score using the Oxford hip questionnaire was 15 (mean 23.5; range 12 to 41). These outcomes compare favourably with those reported at 6 months follow up after conventional total hip replacement by the Oxford group (OHQ median score 22; mean 24.3 (12 to 51)). We conclude that resurfacing metal on metal hip replacement gives comparable results to total hip replacement at early follow up. The age of the Oxford groups patients was considerably older than ours (75 years), and a comparative trial of resurfacing versus conventional hip replacements will be required to determine which gives better short and long term results in young patients. There may be more variability in pain relief after resurfacing THR than after conventional THR, but this will require a larger study to determine with confidence

Aims: To compare the results of resurfacing hip arthroplasty with conventional total hip replacement and to find out any differences in complication rates, discharge patterns and the resulting financial implications. Trial Design: Retrospective analysis comparing resurfacing hip arthroplasties to conventional total hip replacements in patients who were 65 years old or younger at the time of operation. Criteria for comparison were blood loss, post operative complications (including the need for blood transfusion), revision of arthroplasty and the length of hospital stay. Materials and Methods: All patients who had resurfacing arthroplasty in our hospital were included in the study (77 patients), and a similar group who had total hip replacements in the same time period were randomly selected for comparison. Case notes, computer records as well as X-rays were used to identify postoperative complications, especially DVT’s ,PE’s, neuro-vascular injuries, infection, fractured neck of femur and the need for revision of an arthroplasty. A detailed analysis of all revision arthroplasties including the causes, failure pattern of implant and the type of revision hip arthroplasty used and its cost implication was made. We also compared the pre and post-operative haemoglobin and units of blood transfused, if any. A comparison was also made of discharge pattern of these two groups of patients. A student t-test was performed to observe any difference in these two group. Results:. Resurface hip arthroplasty Group: Average age 52.1 years; pre-operative Hb 14.22gm/dl; postoperative Hb.10.95gm/dl; average blood loss 3.28 gm/dl; Total hips revised 12; Average length of stay 8.53 days. Total hip arthroplasty Group: Average age 58.8 years; pre-operative Hb 13.97gm/dl; post-operative Hb 10.65m/dl; average blood loss 3.5 gm/dl; Total hips revised 0; Average length of stay 8.9 days. Conclusions: 1.There were no appreciable differences between these two group as far as the usual complications, blood loss and length of stay are concerned. 2. There was appreciable difference in revision rate, which has significant cost implication for health authority and patients

Systemic concentrations of metal ions (cobalt and chromium) are persistently elevated in patients with metal-on-metal hip resurfacing (MOMHR) compared to conventional total hip arthroplasty (THA). Several studies by us and others have described the detrimental effects of metal exposure on survival and function of various cell types in-vitro, but the mechanisms for these effects remain unclear. Epigenetic modifications following chronic metal exposure is a possible mechanism that could mediate these effects. Here we test the methylation status in genomic DNA from MOMHR (“cases”) and THA (“controls”) patient-groups, and its correlation with circulating metal levels. The cohort consisted of 34 patients with a well-functioning MOMHR at a median follow-up of 9.75 years. These were individually matched for gender, age and time-since-surgery to a non-exposure group consisting of patients with THA. Genomic DNA was isolated from blood samples and cell composition estimated using the ‘estimateCellCounts’ function in ‘minfi R-package’. Methylation was assessed using the Illumina 450k BeadChip array analysing 426,225 probes. Logit model was fitted at each probe with case/control status as independent variable and covariates of gender, age, time-since-surgery, smoking, non-arthroplasty metal exposure, and cell composition. DNA methylation age was assessed using an online calculator (. https://dnamage.genetics.ucla.edu/. ) and comparisons made between cases and controls, and correlated with circulating metal levels. Cell distributions did not differ between the cases and controls (Wilcoxon test p<0.17) with no probe having an association at 5% FDR. Circulating metal levels and LVEDD also had no association with any probe at 5% FDR. There was no preferential age acceleration between cases and controls (Wilcox p<0.7), and it had no correlation with plasma-chromium or blood-cobalt levels (p<0.9). In summary, large methylation changes following MOMHR seem to be absent, compared to THA. Future research with larger samples will be needed to clarify the presence and extent of small methylation changes

A conceptually new, to the North American market, acetabular design is currently available when performing a total hip arthroplasty – the dual mobility socket. Essentially this is a press-fit acetabular component with a polished surface (either modular or monoblock) that articulates with a large polyethylene head with a 28 mm ball inserted into that polyethylene in a similar fashion to a bipolar design. Proponents of this design advocate its use to reduce the risk of dislocation, and it is being offered as an alternative to constrained liners and also as a potential prophylactic application in revision and high risk patients. The concerns regarding this construct include:. Wear - A large polyethylene head articulating against a polished metal surface may have much greater wear than a conventional metal against polyethylene bearing. Hip simulator data has shown this previously. Additionally there are two articulating surfaces, potentially leading to a greater combined wear than one would see with just a singular surface. Clinical data - At present there are predominately short term published reports on this implant, many from the same centers. There are no control groups with other implants in these same “at risk” patients. There is no registry data to date on this implant. Patient Population - A difficult question to answer is which patient is at risk for dislocation and if one was going to apply this new technology, which patient would receive it? In the original published series, 26% of patients undergoing THA had this implant. Does the increased risk of wear and osteolysis warrant the use of this implant in a primary setting?. Unique complication - A unique complication has been described labeled intra-prosthetic dislocation. This occurs when the inner femoral ball disassociates from the polyethylene. The incidence has been reported up to 2% in some series. This complication alone equals the current rate of hip instability in a Medicare database with a conventional total hip replacement. Cost - In our current era of containing health care costs, this implant is offered to most at a significant cost premium to a more conventional total hip construct, without evidence of superiority, or for that matter equivalence at this point. There are many options available to both manage and to prevent hip instability. Any new implant must show equivalence to current devices on the many fronts of wear, fixation, mid-term results, complications and costs

Hip resurfacing offers an attractive alternative to conventional total hip arthroplasty in young active patients. It is particularly advantageous for bone preservation for future revisions. Articular Surface Replacement (ASR) is a hip resurfacing prosthesis manufactured by DePuy Orthopaedics Inc. (Warsaw, IN). The manufacturer voluntarily recalled the ASR system in 2010 after an increasing number of product failures. The present study aimed to determine the long-term results in a large cohort of patients who received the ASR prosthesis. Between February 2004 and August 2010, 592 consecutive hip resurfacings using the ASR (DePuy Orthopaedics Inc., Warsaw, IN) resurfacing implant were performed in 496 patients (391 males and 105 females). The mean age of the patients at the time of the surgery was 54 (range: 25 to 74) years. Osteoarthritis was the most common diagnosis in 575 hips (97.1%). The remaining patients (2.9%) developed secondary degenerative disease from ankylosing spondylitis, avascular necrosis, developmental hip dysplasia, and rheumatoid arthritis. Clinical and radiographic information was available for all patients at the last follow up. Cobalt (Co) and chromium (Cr) levels were measured in 265 patients (298 hips) by inductively coupled plasma-mass spectrometry (ICP-MS). The average follow up of the study was 8.6 years (range: 5.2 to 11.6 years). The mean Harris hip and UCLA scores significantly improved from 44 and 2 pre-operatively to 85.3 and 7.1 respectively. The median Co and Cr ion level was 3.81 microgram per liter and 2.15 microgram per liter respectively. Twenty-seven patients (5.4%) were found to have blood levels of both Co and Cr ions that were greater than 7 microgram per liter. Fifty-four patients (9.1%) were revised to a total hip arthroplasty. Kaplan-Meier survival analysis showed a survival rate of 87.1% at 8.6 years with revision for any cause and 87.9% if infection is removed. A significantly higher survival rate was observed for the male patients (90.2%, p <0.0001) and for the patients with ASRs with femoral heads diameters larger than 52 mm (90.1%, p=0.0003). This study confirms that patient selection criteria are of great importance to the overall survivorship of hip resurfacing arthroplasty. Improved clinical results have been reconfirmed with the use of larger diameter femoral heads

INTRODUCTION. THA as primary treatment for displaced femoral neck fractures in elderly still remains a prominent concern. Overall dislocation rate after total hip arthroplasty (THA) is reported form 1∼5%. But, it is quiet different in situation of femur neck fracture in elderly. The THA is associated with higher rates of dislocation (8%∼11%) in eldery compared to hemiarthroplasty even though THA showed better clinical and functional scores. Recently resurgence about THA using DMC comes after improvement of manufacturing technology. The aim of this prospective multicenter study is to assess the rates of dislocation and re-operation for displaced femoral neck fractures in elderly with THA with Dual Mobility Cup (DMC) and to review systematically comparison of previous reports. Up to our knowledge, this is first report from asian conutry about the clinical outcomes THA using DMC for displaced femur neck fracture in elderly. METHODS. Prospective consecutive groups of patients treated for displaced femoral neck fractures by three surgeons at each three center were included. 131 hips underwent THA with DMC for acute displaced femoral neck fracture in patients aged older than 70 years. Data regarding rates of dislocation and re-operation were obtained by review of medical records. Additionally From 2009 which the US FDA first approved the DMC, the authors searched reports regarding to THA using DMC for displaced femur neck fracture in elderly using the MEDLINE including cases series and comparative studies with bipolar hemiarthroplasty and THA. Therefore, current report was compared with previous reports. RESULTS. The reports about THA using DMC for displaced femur neck fracture in elderly were limited. Most of them comes from European countries. Comparative study with THA from Sweden reported the dislocation rate of THA using DMC with average aged 75-year is 0%. In Denmark study, the bipolar hemiarthroplasty showed 14% of dislocation rate for femur neck fracture in patient aged 75 years but, THA using DMC is 4.6%. Two cases series from French reported about 1–4% in patients aged 80 years. In our multicenter study, dislocation occurred in 6/131 hips (4.6%) treated with total hip arthroplasty using DMC for displaced femur neck fracture over 70 years older patients. Reoperations including periprosthetic fracture and fixation failure of cup were required in 1/43 (2.3%) hips treated with total hip arthroplasty using DM cup. These result is comparable to European reports. DISCUSSION AND CONCLUSION. Our findings indicate that THA with DMC can not guarantee to prevent the dislocation for high risk elderly patients, but the overall rate of dislocation can be comparable to those of bipolar hemiarthroplasty and reduced compared to conventional total hip arthroplasty. This result might be a valuable messages for burden of the medical cost by dislocation after arthroplasty especially for older patient. Therefore, adding advnatages of THA compared with hemiarthroplasty, the THA with DMC can be a wise option for displaced femoral neck fracture in eldely. But, the randomized controlled study still is needed to clarify to confirm this findings

Aims

To establish the survivorship, function, and metal ion levels in an unselected series of metal-on-metal hip resurfacing arthroplasties (HRAs) performed by a non-designer surgeon.