Aims

Postoperative length of stay (LOS) and discharge dispositions following arthroplasty can be used as surrogate measurements for improvements in patients’ pathways and costs. With the increasing use of robotic technology in arthroplasty, it is important to assess its impact on LOS. The aim of this study was to identify factors associated with decreased LOS following robotic arm-assisted total hip arthroplasty (RO THA) compared with the conventional technique (CO THA).

Aims

Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA.

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

The aim of this study was to investigate the potentially increased risk of dislocation in patients with neurological disease who sustain a femoral neck fracture, as it is unclear whether they should undergo total hip arthroplasty (THA) or hemiarthroplasty (HA). A secondary aim was to investgate whether dual-mobility components confer a reduced risk of dislocation in these patients.

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

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.

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

Objectives. The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, component inclination, component version, and leg-length correction. Materials and Methods. This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. Patients undergoing conventional manual THA and robotic-arm assisted THA were well matched for age (mean age, 69.4 years (. sd. 5.2) vs 67.5 years (. sd. 5.8) (p = 0.25); body mass index (27.4 kg/m. 2. (. sd. 2.1) vs 26.9 kg/m. 2. (. sd. 2.2); p = 0.39); and laterality of surgery (right = 28, left = 22 vs right = 12, left = 13; p = 0.78). All operative procedures were undertaken by a single surgeon using the posterior approach. Two independent blinded observers recorded all radiological outcomes of interest using plain radiographs. Results. The correlation coefficient was 0.92 (95% confidence interval (CI) 0.88 to 0.95) for intraobserver agreement and 0.88 (95% CI 0.82 to 0.94) for interobserver agreement in all study outcomes. Robotic THA was associated with improved accuracy in restoring the native horizontal (p < 0.001) and vertical (p < 0.001) centres of rotation, and improved preservation of the patient’s native combined offset (p < 0.001) compared with conventional THA. Robotic THA improved accuracy in positioning of the acetabular component within the combined safe zones of inclination and anteversion described by Lewinnek et al (p = 0.02) and Callanan et al (p = 0.01) compared with conventional THA. There was no difference between the two treatment groups in achieving the planned leg-length correction (p = 0.10). Conclusion. Robotic-arm assisted THA was associated with improved accuracy in restoring the native centre of rotation, better preservation of the combined offset, and more precise acetabular component positioning within the safe zones of inclination and anteversion compared with conventional manual THA

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

The Birmingham hip resurfacing metal-on-metal arthroplasty was introduced in 1997 and has shown promising short- to mid-term results. We used radiostereophotogrammetric analysis (RSA) to study the stability of 20 resurfacing arthroplasties over a follow-up period of 24 months. Radiological examinations for RSA were performed immediately after surgery and at two, six, 12 and 24 months after operation. Precision and detection of migration thresholds (non-zero movement) were calculated. All the results corresponded well to those found in similar experimental arrangements with standard hip prostheses. Migration of the cup and vertical and mediolateral migration of the head were calculated. The values were low at two years compared with those of earlier studies of cemented femoral components in conventional total hip replacements indicating that there was no evidence of excessive early migration or loosening of the components

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.

BACKGROUND. We originally performed metal-on-metal hip resurfacing using a Townley designed Vitallium Total Articular Replacement Arthroplasty (TARA) curved stemmed prosthesis. Neither the acetabular or femoral components were cemented or had porous coating. The bearing surfaces were consistently polar bearing. The surgical objectives were to preserve bone stock, maintain normal anatomy and mechanics of the hip joint and to approximate the normal stress transmission to the supporting femoral bone. The functional objectives were better sports participation, less thigh pain and limp, less perception of a leg length difference and a greater perception of a normal hip. Metal-on-metal was selected to conserve acetabular bone and avoid polyethylene associated osteolysis. Relatively few cases were performed until the Conserve Plus and later the Birmingham Hip Resurfacing systems became available. METHODS. We examined the results of metal-on-metal hip resurfacing in patient with at least 10 years of follow-up and an age less than 50 at the time of surgery. We did not have access to the Birmingham Prosthesis until 2006. We performed 101 TARA procedures and 397 Conserve Plus procedures for 357 patients. For the combined series the mean age was 43 and 62% of patients were male. 34 patients had a conventional total hip replacement on the contralateral side. We used both the anterolateral and posterior approaches. All acetabular components were placed without cement and all the Conserve Plus Femoral Components were cemented. RESULTS. There were no implant related failures with the TARA prosthesis. The average Harris Hip Score was 93. There were 2 revisions for femoral neck fracture at years 8 and 14 and one revision for infection. There was one dislocation but no instance of implant loosening. There were 29 (7%) revisions with the Conserve Plus Prosthesis. 14 revisions were for adverse reactions to metal wear debris and 10 of these patients had femoral components of size 46 mm or smaller. There were 5 revisions for acetabular loosening and 3 for femoral loosening. There were 7 revisions for femoral neck fracture and infection. The limb lengths were measured to be within 1 cm of equal in 98% of patients. 95% of patients had a UCLA activity score above 6 and 96% of patients rated their outcome excellent or good. 32 of 34 patients preferred their hip resurfacing to total hip replacement. The Kaplan-Meier survivorship was 93%. Narrowing of the femoral neck was seen in 9% of patients but acetabular osteolysis was not seen. Signs of impingement of the femoral neck against the acetabular prosthesis were seen in 14% of patients. CONCLUSIONS. Metal-on-metal hip resurfacing has been performed for more than 40 years using predicate prostheses such as the Townley TARA. The results of metal-on-metal resurfacing are favorable even in young and very active individuals. There were no instances of medical illness related to metal-on-metal implants with up to 41 years of follow-up. Metal-on-metal hip resurfacing has favorable outcomes at 10 years. There is an increased chance of an adverse reaction to metal wear debris with femoral component sizes 46 mm or smaller

Peri-articular soft-tissue masses or ‘pseudotumours’ can occur after large-diameter metal-on-metal (MoM) resurfacing of the hip and conventional total hip replacement (THR). Our aim was to assess the incidence of pseudotumour formation and to identify risk factors for their formation in a prospective cohort study. A total of 119 patients who underwent 120 MoM THRs with large-diameter femoral heads between January 2005 and November 2007 were included in the study. Outcome scores, serum metal ion levels, radiographs and CT scans were obtained. Patients with symptoms or an identified pseudotumour were offered MRI and an ultrasound-guided biopsy. There were 108 patients (109 hips) eligible for evaluation by CT scan at a mean follow-up of 3.6 years (2.5 to 4.5); 42 patients (39%) were diagnosed with a pseudotumour. The hips of 13 patients (12%) were revised to a polyethylene acetabular component with small-diameter metal head. Patients with elevated serum metal ion levels had a four times increased risk of developing a pseudotumour. This study shows a substantially higher incidence of pseudotumour formation and subsequent revisions in patients with MoM THRs than previously reported. Because most revision cases were identified only after an intensive screening protocol, we recommend close monitoring of patients with MoM THR

Metal-metal hip resurfacing offers the advantage of conservation of femoral bone stock. In addition, the implant may offer enhanced resistance to dislocation in comparison with conventional total hip arthroplasty. We present a series of 32 female patients with one to 4 year follow up (mean age 57 ranges 50–70 at time of surgery). All patients required hip arthroplasty. Careful preoperative selection was carried out with particular attention paid to estimation of bone density. A standard resurfacing operation was carried out. Patients had pre and postoperative WOMAC and SF36 scoring. All patients were followed closely in the post operative period. No significant complications were noted at follow up. In our study we have shown that given careful patient selection Birmingham hip resurfacing can be safe and reliable form of arthroplasty

Introduction. Bearing surfaces used for total hip arthroplasty must have characteristics including bio-compatibility, low friction and low wear rate. Bearing combinations are generally characterised as Soft on Hard/Hard. In general, all newer bearing combinations have reduced wear but may present with other issues that impact on patient outcomes. Materials. The Australian Orthopaedic Association – National Joint Replacement Registry classifies bearing surfaces into six categories. These are metal on polyethylene, ceramic on polyethylene, metal on metal, ceramic on ceramic, ceramic on metal and a sixth category relating to a small number of procedures where the bearing surface is yet to be classified. 147,422 conventional total hip arthroplasty procedures have been recorded by the Registry between 1 September 1999 and 31 December 2008 and analysis has been performed of the cumulative percentage revision in relation to bearing surface. Results. In general, metal on polyethylene has the lowest risk of revision compared to all other bearing surfaces and metal on metal has the highest revision rate. The risk of revision, however, does vary depending on head size, with larger head sizes having a lower risk of revision with the exception of metal on metal. Conclusion. When deciding which bearing surface is suitable for patients it must be emphasised that wear reduction is only one of several considerations when choosing the most appropriate combination

A 34-year-old woman with a benign form of osteopetrosis developed osteoarthritis of the hip. In order to avoid the difficulties associated with inserting the femoral component of a conventional total hip arthroplasty, a hybrid metal-on-metal resurfacing was performed. There were several technical challenges associated with the procedure, including the sizing of the component, press-fit fixation of the acetabular component and femoral head preparation, as well as trying to avoid a fracture. No surgical complication occurred. After more than a year following surgery, the patient showed excellent clinical function and remained satisfied with the outcome. We conclude that the hybrid metal-on-metal resurfacing arthroplasty represents a valuable option for the treatment of patients with osteopetrosis and secondary hip osteoarthritis

Background. Hip resurfacing has resurged in the last decade due to a renewed interest in metal on metal bearing. One of the proposed advantages is ease of revision of the femoral component. Short term functional results after femoral revision are similar to those after conventional total hip replacement. Survival and function after revision of the acetabular component only or of both components have not been reported. We aimed to assess hip function and implant survival after revision of the acetabular component for failed Birmingham hip resurfacing (BHR). Methods. The Oswestry Outcome Centre collected data prospectively on 5000 patients who underwent hip resurfacing between 1997 and 2002. Of these, 182 hips were revised: 42% had revision of the femoral component only, 8% revision of the acetabular component only, and 50% revision of both components. This study analyzed patients who had revision of the acetabular component, either in isolation or in combination with the femoral component. Results. In the isolated acetabular revision group the median Harris Hip Score was 74 at a mean of 4.5 years post-revision. In the both components revision group the median Harris hip score was 85 at a mean of 4 years. There was no significant difference in function between the groups. Kaplan-Meier survivor ship analysis after revision showed an average survival of 91% at 10 years. There was a significant difference between survival of isolated acetabular revision (75%) and both component revision (96%). Conclusions. Revision total hip replacement subsequent to failure of hip resurfacing has good outcome and good midterm survival. Isolated acetabular revision and revision of both components had similar function but survival was significantly worse in the isolated acetabular revision group

Introduction: Peri-prosthetic fractures following hip resurfacing arthroplasty are difficult fractures to treat. The surgeon is faced with the task of either attempting to fix the fracture if feasible or revise the resurfacing implant to a conventional total hip replacement. Method & Results: Here we report of a novel way of fixing a peri-prosthetic fracture following resurfacing hip arthroplasty using Polyaxial locking plate fixation. A 53 year old man sustained a intertrochanteric fracture below his resurfacing metal on metal hip prosthesis following a fall. He had his hip resurfaced 3 years back for osteoarthritis in another hospital. He underwent surgery to fix the fracture using a polyaxial locking plate with no post-operative complications. He was mobilised non-weight bearing for the initial six weeks and weight bearing as tolerated thereafter. He went on to union and was moblising without any problems in three months time. His follow-up x-rays at 8 months showed fracture healed with no evidence of prosthesis problems. Discussion: There are various methods of treating a periprosthetic fracture of a well fixed resurfaced hip implant. The two types of management are open reduction and internal fixation and revision to a stemmed hip implant. These fractures can be fixed with cannulated hip screws, blade plate device or plating with screws avoiding the stem of the resurfacing prosthesis. We used the polyaxial locking plate device with good result thereby avoiding the need for revision surgery with its attendant risks. Using this implant is a useful alternative for these fracture patterns

Aim: Component positioning may be adversely affected by minimally invasive approach in total hip replacement due to restricted visualization. Problems with proper alignement are suggested to concern anteversion more than inclination and occur particulary in the lateral position. Method: 53 patients were enrolled prospectively randomised to each group. First group (standard group, n= 30pts) underwent conventional total hip replacement in supine position and transgluteal approach and second group (MIS group, n= 23pts) underwent THR using minimally invasive anterior approach in lateral decubitus position Every group was operated on by two experienced senior surgeons. Desired cup position was 40°–45°inclination and 15–20° anteversion for the MIS group and 45°inclination and 15 ° anteversion for standard group. Postoperatively all patients had pelvic CT scan. Inclination and anteversion were determined by an independent observer using a 3-D model and planning software, the operative definition was used according to Murray. Results: Mean inclination/anteversion in the MIS group was 39°(26°–50°)/25°(10°–47°), and 44°(29°–57°)/22°(1°–53°) within the standard group. Standard deviation for inclination was 7° for both groups, and 10° (MIS group) vs 14° (standard group) for anteversion. The difference in the mean values regarding inclination was greater than would be expected by chance; there was a statistically significant difference (P = 0,010). Discussion: In general cup positioning in both groups was less steep and more anteverted as presumed. The standard deviation for inclination was the same in both groups, but the standard deviation for anteversion was less in MIS group, that means less outliers regarding anteversion. Cup positioning in minimally invasive total hip replacement is safe compared to traditional approach. Navigation technique was discussed to equalize the drawback of MIS. However, tools like imageless navigation may further improve the cup position even in traditional approach

Metal on metal hip resurfacing was introduced in 1992 by Derek McMinn initially using an all cementless device and then an all cemented device. A hybrid resurfacing with a cemented femoral component and a cementless acetabular component was introduced in 1994. The manufacturer of the hybrid hip resurfacing was changed in 1996. Since 1997 the Birmingham hip resurfacing has been in continuous use. The device is approved by NICE (National Institute for Clinical Excellence) for use within the NHS in patients with Osteoarthritis of the hip. The device is not yet approved for use in patients with Rheumatoid Arthritis and other types of inflammatory arthritis. There are concerns regarding bone quality in rheumatoid patients, which may result in a high incidence of component loosening or femoral neck fracture. Conventional total hip replacement is a successful procedure in inflammatory arthritis however with modern treatments producing increased activity levels there are concerns about polyethylene wear. The author has performed metal on metal hip resurfacing in patients with inflammatory arthritis over the past 12 years. A total of 170 patients have been operated on with 198 resurfacings. 33% of patients have a diagnosis of some type of inflammatory arthritis. The outcomes have been assessed using Oxford hip scores and long term clinical and radiological review. Our results indicate that there is a minimal risk of femoral neck fracture and a minimal risk of component loosening when the device is used with this approach in patients with inflammatory arthritis

We have compared the biomechanical nature of the reconstruction of the hip in conventional total hip arthroplasty (THA) and surface replacement arthroplasty (SRA) in a randomised study involving 120 patients undergoing unilateral primary hip replacement. The contralateral hip was used as a control. Post-operatively, the femoral offset was significantly increased with THA (mean 5.1 mm; −2.8 to 11.6) and decreased with SRA (mean −3.3 mm; −8.9 to 8.2). Femoral offset was restored within . sd. 4 mm in 14 (25%) of those with THA and in 28 (57%) of the patients receiving SRA (p < 0.001). In the THA group, the leg was lengthened by a mean of 2.6 mm (−6.04 to +12.9), whereas it was shortened by a mean of 1.9 mm (−7.1 to +2.05) in the SRA group, compared with the contralateral side. Leg-length inequality was restored within . sd. 4 mm in 42 (86%) of the SRA and 33 (60%) of the THA patients. The radiological parameters of acetabular reconstruction were similar in both groups. Restoration of the normal proximal femoral anatomy was more precise with SRA. The enhanced stability afforded by the use of a large-diameter femoral head avoided over-lengthening of the limb or increased offset to improve soft-tissue tension as occurs sometimes in THA. In a subgroup of patients with significant pre-operative deformity, restoration of the normal hip anatomy with lower pre-operative femoral offset or significant shortening of the leg was still possible with SRA

Patients with Neuromuscular disorders who have an arthritic hip joint present unique challenges. Due to inadequate bone stock, bony deformity and muscle imbalance there is a potentially increased risk of dislocation. These patients who have undergone conventional total hip replacement in the past, have been immobilised post-operatively in a hip spica to prevent post-op dislocation. Large heads are inherently more stable and adequately treat these patients, without the need for post-operative immobilisation. We present our experience with large head replacement in this group of patients. Eight patients, five with cerebral palsy, two with Down’s Syndrome and one with Cornelia de large Syndrome, who underwent total hip replacement with a large head prosthesis were reviewed. Their average age was 44.5 years and patients were followed up for maximum 51 months. Patients were assessed with respect to pre- and post-op pain, mobility and function. Hip scores have not been found to be useful in assessing these patients. Two Birmingham Surface replacements were used and six large heads on conventional stems, with large uncemented cups. In all patients there was improvement in pain and function. Four patients had improvement in their ambulatory status. In none did this worsen. Despite no post-operative immobilisation, there was only on dislocation. This was due to error in cup positioning, an error in the early learning curve. Despite the small numbers and short follow up, we feel that large head replacement is a viable alternative to conventional hip replacement in these difficult cases

Purpose. There are some concerns about doing hip resurfacing arthroplasty in ONFH due to bone defect which can cause mechanical weakness of femoral component and highly active young age of patients which can cause high wear rate and failure rate. The purpose of this study is to verify the HRA is safe procedure in ONFH in the aspect of mechanical and biological issue. Materials and Methods. Between December 1998 and May 2005, 185 hips of 169 patients underwent MoM HRA using Birmingham Hip Resurfacing System® at single center. 166 hips (26 hips of female, 140 hips of male) of 144 patients have been reviewed for at least 7 years after MoM HRA. Mean follow-up period was 101.8 (84–178) months. Their mean age at the time of operation was 37.7(16–67) years old. Clinically, Harris hip scores (HHS), UCLA activity scores and range of motion were evaluated. Radiologically, the extent of necrotic area in preoperative MRI and radiolucency around implants, narrowing of retained neck, impingement, stress shielding, and heterotopic ossification were evaluated in the serial anteroposterior and groin lateral radiographs of hip. Complications were defined as joint dislocation, infection, implant loosening, femoral neck fracture and pseudotumor. Failure was defined as revision arthroplasty due to the complications. Results. The extent of necrotic area in preoperative MRI was average 37.6 (13.3–65)%. Clinically, average HHS was improved from 81.7 points to 98.5 points at last follow-up. Average UCLA activity score at last follow-up was 9.0 points. Range of motion at last follow-up was very satisfactory. There was no patient with severe pain around hip joint. Radiologically, radiolucency was shown around acetabular component in 2 cases (1.2%) and around stem of femoral components in 3 cases (1.8%). Fracture of femoral neck was seen in 1 case(0.6%). Moderate narrowing changes of retained femoral neck were noticed in 4 cases (2.4%). Impingement was seen in 12 cases (7.2%). We found only 1 case of osteolysis at Gruen zone III of acetabulum. Heterotopic ossification was found in 5 cases (3.0%). There was no case with hip dislocation, infection or pseudotumor. Revision surgeries after the primary resurfacing arthroplasty were performed in 4 cases (2.4%). Three hips were revised to the conventional total hip arthroplasty (THA) because of loosening of acetabular component and femur neck fracture. One case of femoral component loosening was revised to THA using big metal head with retained acetabular component. Conclusions. MoM HRA in ONFH demonstrates good survivorship in average 101.8 months follow-up study. Most of patients show excellent clinical results with high level of activity postoperatively. Prevalence of complications is extremely lower than concern including the allergic reaction to the metal ion. There was no mechanical failure related to bone defect due to ONFH. This results suggests that MoM HRA in ONFH less than 50% of extent of necrosis can be justified

Introduction: The hip resurfacing in younger patients is being performed more frequently in the UK. At the same time conventional Total Hip Replacement (THR) is also being performed.. We carried out a study to compare the patient satisfaction and outcome following Birmingham Hip Resurfacing (BHR) and Total Hip Replacement (THR) in patients below the age of 55 years. Methods: There were 93 BHR in 73 patients and 74 THR in 64 patients performed between February 1997 to June 2005.. Retrospective evaluation of notes and complications were identified. We carried out our study using Oxford Hip score and Modified WOMAC questionnaire by postal and telephonic survey. Results: We found that mean length of stay was 4.5 days for BHR and 6.4 days for THR patients. (P< 0.0001) The dislocation rate was 0% for BHR as oppose to 4% for THR. (P< 0.05) The mean Oxford Hip score improved from pre-operative 43 to 14 for BHR as oppose to 48 to 22 for THR patients. The mean modified WOMAC score improved from 21 to 8.4 for BHR as oppose to 25 pre-operative score to 12 for THR. We also found early and sustained improvement in these scores for BHR as compare to THR during their follow-up within 6 months to 8 years. The improvement in pain score was 100% following BHR as opposed to 84% for THR. Following BHR 70% patients were very active or active as oppose to only 30% of THR patients. Return to the work and sporting activities following BHR was at a mean of 9 weeks as oppose to 14 weeks following THR. (P < 0.05) The level of satisfaction was 98% following BHR as oppose to 84% following THR. (P=0.356)

Introduction: Conventional total hip replacement has a high rate of failure in young or high demand patients due to polyethylene wear, therefore, we perform a metal on metal hip resurfacing in these patients. Materials and Methods: The cup is all chrome cobalt alloy, with HA coating and the beads of the porous ingrowth surface are integrated with the substrate metal. The metal head is þxed with low viscosity cement, after careful precise preparation of femoral head.33 hybrid hip resurfacing in 29 patients. Average age was 42.8 years. Results: Harris Hip Score: 34.2 points average preoperatively and 97.1 points at the last examination. The average follow-up was 14.7 month. Discussion: The advantages: Minimal bone resection which makes for easier future revision, normal proximal femoral loading that hence avoidance of the stress shielding present in standard hip replacements, less risk of dislocation with greater range of motion, the physiological biomechanics of the joint is maintained, proprioception is maintained and we have noted that the postoperative recovery is extremely smooth and quick. The disadvantages: Leg length and neck version cannot be altered. Hip resurfacing is, technically, a demanding procedure. Contraindications: osteoporosis, varus neck. Conclusions: Our early results are encouraging. We believe that metal on metal hybrid resurfacing is a legitimate alternative for active patients who require hip arthroplasty

Background: Because of the changing demographics of the population and improvements in prosthesis design and surgical technique, ever-increasing numbers of younger patients are undergoing joint replacement. Younger patients often receive hip resurfacing rather than conventional THR because of the preservation of bone stock and the lower risk of dislocation. However, pain relief and restoration of function for younger patients is particularly important to continue with a normal, active life. Yet there is little existing research to establish if hip resurfacing results in better patient-reported outcomes than conventional total hip replacement (THR). Therefore, the aim of this study was to compare patient-reported outcomes after hip resurfacing and THR, after controlling for age, gender, general health and length of follow-up. Methods: A postal survey was sent to all patients who had a hip resurfacing or primary THR between April 2004 - April 2006 at the Avon Orthopaedic Centre. To assess hip pain and function, quality of life, general health and satisfaction with the outcome of surgery, the questionnaire included the WOMAC, HOOS Quality of Life Scale, SF-12 and a validated satisfaction scale. The continuous outcome scores were compared for those who had a THR and those who had hip resurfacing, after adjusting for age, sex, general health and length of follow-up, using Analysis of Variance. Results: Completed questionnaires were received from 911 THR patients and 157 hip resurfacing patients (response rate of 68% and 71%). Hip resurfacing patients had a mean age of 52 years and 71% were male. THR patients had a mean age of 68 years and 37% were male. After controlling for the effects of age, gender, general health and follow-up length, there was no significant difference in pain (p=0.70), function (0.85), hip-related quality of life (p=0.66) or satisfaction (0.09) between hip resurfacing patients and THR patients at 1–3 years post-operative. Conclusions: The findings from this study suggest that hip resurfacing has no short-term clinical advantage over conventional THR. A prospective randomised controlled trial is necessary to further compare patient outcomes after hip resurfacing and THR

Metal-on-Metal devices generate significantly lower volumetric wear than conventional total hip replacements. However, clinically some patients may suffer some form of laxity in their joints leading to subluxation of the joint, which in turn may cause edge loading of an implant thereby increasing the chances of failure due to higher than expected wear. In this study, the effect of subluxation on MoM implant wear was investigated on a hip joint simulator. Materials & Methods. Two groups of 44 mm MoM devices were tested, n=3 in each group. The devices were subjected to 1 and 2 mm of subluxation. The flexion/extension was 30° and 15° respectively, internal/external rotation was ±10°, and cup inclination was 35°. The force was Paul type stance phase loading with a maximum load of 3 kN, with ISO swing phase load of 0.3 kN, run at 1 Hz. The test was carried out on a ProSim deep flexion & subluxation hip wear simulator (SimSol, UK). Rather than separating the head and the cup (microseparation), or reducing the swing phase load, this simulator is equipped with a novel mechanism to achieve translation of the head, while subjecting the devices to subluxation. During the swing phase, a controlled lateral force necessary for the translation of the head is applied by a cam mechanism, head retraction will then take place on heel strike. The lubricant used was new born calf serum with 0.2 wt. % sodium azide concentration diluted with de-ionised water to achieve average protein concentration of 20 g/l. Lubricant was changed every 250k cycles. Gravimetric wear measurements have been taken at 0.25 & 0.5 Mc stages. Results. Tests conducted with 1mm (Group 1) and 2mm (Group 2) subluxation significantly increased volumetric wear compared to standard hip simulator tests [1]. At 0.5 million cycles, group 1 and 2 produced an average volume loss of 4.38±0.98 mm. 3. (95% CL) and 7.07±1.64 mm. 3. (95% CL) respectively. Discussion/conclusion. Well positioned and well-fixed hip implants perform well in vitro and in vivo; however optimal performance a device can be affected by a number of factors from design, technical factors, patient factors, surgical technique to position of the device in vivo. The study presents test results of a hip joint simulator with a subluxation mechanism to simulate clinically relevant subluxation during the swing phase of a gait cycle under the ISO swing phase load of 0.3kN, with differing levels of luxation. Increasing the level of subluxation in turn increased volumetric wear due to greater head contact at the superior rim of the cup. Further tests will be conducted with high cup inclination angles (>45°) and subluxation to determine the effect upon wear. Tests which can simulate the (ideal and adverse) conditions clinically can help to improve the design and understanding of implant behaviour in vivo

Metal-on-metal hip resurfacing arthroplasty is a conservative procedure that is becoming an increasingly popular option for young arthritic patients most likely to undergo a secondary procedure in their lifetime. The stability of the acetabular component is of particular concern in these patients who show an increased risk of failure of the cemented acetabular cups in conventional total hip replacements. The purpose of this study was to examine the initial stability of a cementless interference press-fit acetabular cup used in hip resurfacing arthroplasty and implanted into ‘normal’ versus poor quality bone. Also examined was the effect of the press-fit procedure on the contact mechanics at the cup-bone interface and between the cup and femoral head. A finite element (FE) model of the DUROM resurfacing (Zimmer GmbH) was created and implanted anatomically into the hip joint, which was loaded physiologically through muscle and subtrochanteric forces. The FE models included: a line-to-line, 1mm and 2mm interference press-fit cup. Also considered were two FE models based on the 1mm press-fit cups, in which the material properties of the cancellous and cortical bone tissues were reduced by 2 and 4 times, to represent a reduction in bone quality as seen with age or disease. Increasing the cup-bone interference resulted in a sig-nificant reduction in implant micromotion. All the pressfit models showed predicted cup-bone micromotion below 50 micrometers. This would ensure adequate initial stability and encourage secondary fixation through bone in-growth. The predicted acetabular stresses were found to increase with the amount of press-fit, however, there was no suggestion of a fracture. These stresses would further contribute to securing the cup. Reducing the bone quality showed an increase in the predicted micromotion and increased bone strain. Micromotion was below 50 micrometers, but the predicted compressive bone stresses, necessary for additional implant fixation, was reduced. This implied that poor quality bone would provide unsuitable support medium for the implant. The bearing surface contact mechanics were little affected by the amount of pressfitting

Metal-on-metal bearings have become popular in the last ten years because of a low wear rate combined with the ability to use large head sizes for conventional total hip arthroplasty (THA) and to facilitate resurfacing hip arthroplasty. Further advantages of metal-metal bearings include the fact that they are not at risk for fracture, and they can be made as modular or non-modular acetabular implants. It was recognized early that metal-on-metal implants had the potential to increase serum ion levels, and this was demonstrated in a number of studies. The significance of elevated ion levels, however, for most patients has been primarily a theoretical concern of toxicity, carcinogenesis or mutagenicity, and to date very few, if any, systemic problems related to systemic metal ions have been documented with certainty. Nevertheless, most surgeons have avoided use of the implants in patients who are likely to become pregnant, patients with renal disease, or patients with major systemic illnesses which have a high likelihood of leading to renal disease. Furthermore, most have avoided using them in patients with known dermal metal allergies, even though the connection between dermal metal allergies and metal bearings has not been established. Unexpectedly, an extremely important concern has emerged with metal bearings: the finding of local inflammatory reactions related to metal bearings. These inflammatory reactions can take several forms including pain with a milky effusion, local tissue necrosis, or large fluid collections or pseudotumors. The histology of these different reactions appears to be predominantly lymphocytic in nature and a term for at least some of these reactions has been coined “AVALS”. Whether these local reactions are primarily immunologic in nature or primarily related to dose of local metal ions or debris remains uncertain. While there is much still to be learned, it appears that certain patient populations may be at increased risk for metal reactions, possibly related to implant size (women and smaller patients). It also seems verticallyoriented implants, which create edge loading, increase wear and increase risk of local metal reactions. Perhaps the most important question is the incidence of local metal reactions, which remains to be defined. To date the problems in most series have been infrequent, less than 1 or 2 percent. However, in a few selected series the incidence has been higher, and when screening has been done for asymptomatic patients with fluid or masses around the joint, the rate has been higher in at least one reported series. Surgeons may interpret the importance of local metal reactions differently, but certainly ultimately incidence of this problem will have a very major effect on the future of these bearings

Aims

There is an increased risk of dislocation of the hip after the resection of a periacetabular tumour and endoprosthetic reconstruction of the defect in the hemipelvis. The aim of this study was to determine the rate and timing of dislocation and to identify its risk factors.

Hip resurfacing has in recent years become increasingly popular as an arthroplasty technique, particularly amongst younger patients with more active lifestyles. The procedure has been heralded as a more conservative option, aimed at those wishing to continue strenuous work and recreational activities. In the populalapress and the internet, many claims are made regarding aspects of this procedure, but little evidence has appeared in the scientific literature, either with the results of resurfacing or comparing resurfacing to conventional total hip arthroplasty. We compare the outcomes of a consecutive series of 44 hybrid hip resurfacings against a similar series of 50 conventional hybrid hip arthroplasties (THR’s), all performed in patients aged 60 or under by a single consultant Surgeon. Data on operation time, blood loss, and length of stay, as well as complications, were all prospectively recorded. A modified Harris Hip score was also documented preoperatively, as well as at 6, 26 and 52 weeks postoperatively. In the resurfacing group, there were 28 Male and 16 female, mean age 47.6 years. In the THR group, there were 22 male and 28 female patients, of mean age 51.9 years. The results for the two groups were analysed, and p value of < 0.05 was taken as statistically significant. The results showed no difference in operation time or blood loss. There was a small reduction in average length of stay from 7.1 to 6.4 days, which was not clinically significant, while the Modified Harris Hip Scores at 6 and 52 weeks were the same for both groups. We conclude that whilst it has been previously shown that there is an overall preservation of bone stock following resurfacing arthroplasty, there is no evidence to back additional claimed benefits

Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with regard to whether it provides superior outcomes compared with conventional total hip arthroplasty. The objective of this study was to compare the results of a minimal invasive direct anterior approach (MIDA) with those of a conventional lateral transgluteal approach (CLT). Methods: 120 patients (120 hips) admitted for unilateral total hip arthroplasty were randomized to undergo surgery via minimal invasive direct anterior or conventional lateral transgluteal approach. Patients with a body mass index of more than 35, previous hip surgery, preoperative neurological deficits and with an age of more than 80 years were excluded. Two surgeons performed all procedures. To estimate muscle damage serum creatinkinase was assessed. Blood loss was calculated according to Rosencher by comparing preoperative to postoperative hematocrit. Postoperative pain and the ability to perform the activities of daily living were recorded in a dairy via modified WOMAC first on a daily basis, then on each second day and finally once a week for a total of 12 weeks. WOMAC questionnaire and SF-36 were administered at 6 weeks and 3 months follow-up. Results: The groups were similar demographically. Patients in MIDA group had significantly less total blood loss (p = 0.006), postoperative blood levels of creatinine kinase were significantly lower (p = 0.001). Operative time was similar in both groups, we found no difference in component placement. Physical component summary of SF-36 at 12 weeks follow-up showed a significant benefit for the MIDA group. Averaged modified WOMAC scores and their pain and function subscores demonstrated a clear advantage on every recorded day during the first 12 weeks for MIDA. Median WOMAC sum score and respective pain as well as function subscores were better in the MIDA group at 6 and 12 weeks follow up. Conclusions: A minimally invasive direct anterior approach is superior to a conventional lateral transgluteal approach with regard to blood loss and muscle trauma, resulting in better health related quality of life in the first three months after operation

Introduction: Resurfacing arthroplasty of the hip joint has advantages of minimal bone resection, restoration of normal anatomy, and biomechanical circumstances. This study was undertaken to analyze the clinical and radiographic results of the resurfacing arthroplasty in patients with osteonecrosis of the femoral head (ONFH). Materials and Methods: Between September 1998 and September 2001, 40 hips in 39 patients with ONFH had a resurfacing arthroplasty with the Birmingham Hip Resurfacing (BHR) system. The mean age at the time of operation was 38.3 years. The average follow-up period was 36.8 months after operation. The patients were clinically evaluated by hip pain, Harris hip scores, range of motion, and radiographically evaluated for wear, change of cup position, loosening, and osteolysis. Results: The preoperative Harris hip score averaged 70.4 points and the degrees of flexion and internal rotation were 94° and 8°, respectively. The average Harris hip score at the last follow-up was 95.4 points. The degrees of flexion and internal rotation at last follow-up were 120°, and 20°, respectively. No patient complained of limb length discrepancy or pain in the hip or thigh. Rehabilitation programs and return to normal activities were earlier than that of conventional total hip arthroplasty (THA). There was no osteolysis, change of cup position, loosening, or detectable wear on the latest radiographic evaluation. Conclusions: Our experience with resurfacing arthroplasty for ONFH indicates that the overall results are superior than conventional THA with respect to pain relief, range of hip motion, earlier rehabilitation, and early return to preoperative activity. This procedure with BHR could be an alternative between joint preserving procedure and conventional THA in ONFH especially in younger patients

Introduction: Metal-on-metal hip resurfacing arthroplasty is one option for young and active patients with advanced hip disease. Intraoperative or immediate postoperative femoral neck fractures complicating a metal-on-metal hip resurfacing is a well described complication as a result of neck notching and stress shielding of the femoral head. The literature contains very little evidences on the conservative mode of treatment for peri-prosthetic fractures following the index operation with a favourable and an unfavourable outcome. We report a case of femoral neck fracture incurred three months after metal-on-metal hip resurfacing resulting in a varus malunion. Case report: A 55 year old lady underwent metal-on-metal surface hip replacement for advanced osteoarthritis of the left hip. The implants used were Cormet 2000 uncemented 50mm dual coated cup and cemented 44mm femoral head. Intraoperative bone quality was good and no technical difficulties were encountered. She was admitted three months later with a painful left hip after sustaining a fall. The radiograph confirmed left periprosthetic femoral neck fracture with resurfacing prosthesis in situ. She was scheduled for elective revision surgery of the femoral component. The patient elected to go home with the intention of getting readmitted. Initially lost to follow-up, she self referred after 30 months of her fracture with shortening and persistent painful limp. The clinical examination revealed 1.5 cm of true limb shortening with restricted terminal range of abduction and rotational movements. The radiographs revealed a varus malunited fracture with proximal migration of greater trochanter. The acetabular component was well fixed in situ. She is awaiting revision surgery by conversion to conventional total hip arthroplasty. Conclusion: We report the first case of a malunited femoral neck fracture following metal-on-metal hip resurfacing operation. Femoral neck fractures can heal in these cases but poor compliance and resultant failure to closely observe the patient may have contributed to such an unfavourable outcome. These complications may be prevented by increased compliance and communication with the patients. At the same time, the hospital management and professional staff should be aware of such potential problems to prevent their recurrence