Five-year results of metal-on-metal resurfacing arthroplasty in Asian patients

BIOMECHANICAL STUDY ON MECHANISMS OF FEMORAL NECK FRACTURE AFTER HIP RESURFACING ARTHROPLASTY

Hip resurfacing arthroplasty (HRA) is a long-established procedure. It is a minimally invasive surgery where the surgical wound is relatively small to facilitate a shorter recovery period. HRA remained a popular option among the patients allowing better range of motion of the joint compared to that of total hip arthroplasty (THA). Although HRA is associated with the above advantages, complications involving femoral neck fractures after surgery still occur. Therefore, the present study attempts to assess the impact of stress under various alignment conditions and different scenarios in surgical errors upon the femoral neck in hip resurfacing prostheses (HRP) that may be encountered during the procedure using finite element analysis (FEA) technique. The results showed that anteversion implantation errors on femoral components should be avoided, and that the main reason that causes femoral neck fracture is related to the stress shielding effect generated internally in the femoral neck. Methods to prevent the incidence of such events are a major obstacle to be solved in the future.

Mid- to long-term results of resurfacing hip arthroplasty in Japanese patients: a comparison of osteoarthritic vs non-osteoarthritic patients

Past reports showed good mid-term results of RHA for Japanese patients. However, few reports have compared the mid- to long-term results for RHA in Japanese patients with and without osteoarthritis. Therefore, this study investigated the mid- to long-term results of RHA in Japanese patients with osteoarthritis compared to those without. We conducted a retrospective review of a consecutive series of 92 hips in 80 patients (59 men and 21 women). The minimum follow-up period was 5 years. The JOA hip scoring system was used to clinically evaluate hip function. In the radiological assessment, stem-shaft angle, inclination of the acetabular component, postoperative complications, and adverse reactions around RHA were evaluated. The 10-year survival rate using the Kaplan-Meier method was investigated to compare patients with and without osteoarthritis. A significant difference was observed between the preoperative and postoperative JOA hip scores of either group. Also, the radiological assessment revealed no significant changes in either group. All three revision THAs were performed on patients in the only non-osteoarthritis group. In the osteoarthritis group, the 10-year survival rate was 94% (95% CI 81.8-100) in males and 100% (95% CI 100) for females; in the non-osteoarthritis group, the rate was 80% (95% CI 55.1-100) in males and 66.7% (95% CI 13.3-100) for females. In conclusion, this study showed good mid- to long-term clinical results for young Japanese osteoarthritis patients, with less satisfactory mid- to long-term results in patients without osteoarthritis.

Calcar Femorale in Patients with Osteoarthritis of the Hip Secondary to Developmental Dysplasia

Background

We investigated whether the calcar femorale, a cortical septum in the region of the lesser trochanter of the femur, correlates with results of femoral stem implantation in patients with osteoarthritis of the hip secondary to developmental dysplasia using computed tomography.

Methods

This retrospective study included 277 hips (41 males and 236 females; age, 37 to 92 years) of patients who had presented to Okayama Medical Center with hip pain. Of these, a total of 219 hips (31 males and 188 females) had previously undergone total hip arthroplasty. According to the Crowe classification, 147 hips were classified as Crowe grade I, 72 hips as Crowe grade II–IV, and 58 hips as normal.

Results

The calcar femorale was identified in 267 hips (96.4%). The calcar femorale was significantly shorter and more anteverted in Crowe grade II–IV hips than in Crowe grade I or normal hips. Significant differences in the shape of the calcar femorale were found according to the severity of hip deformity. Three stem designs were analyzed: single-wedge (59 hips), double-wedge metaphyseal filling (147 hips), and modular (13 hips). Single-wedge stems were inserted more parallel to the calcar femorale rather than femoral neck anteversion, while other types of stems scraped the calcar femorale.

Conclusions

The angle of the calcar femorale differs according to the severity of hip deformity, and the calcar femorale might thus serve as a more useful reference for stem insertion than femoral neck anteversion in total hip arthroplasty using a single-wedge stem.

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

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

Revision rates for metal-on-metal hip resurfacing and metal-on-metal total hip arthroplasty - a systematic review

PURPOSE

To compare revision rates of metal-on-metal (MoM) hip resurfacing (HRS) and MoM total hip arthroplasty (THA), as well as the primary causes for revisions.

METHODS

The PubMed database was queried for potentially relevant articles addressing MoMTHA and MoMHRS, a total of 51 articles were included.

RESULTS

The review includes a total number of 5,399 MoMHRS and 3,244 THA prosthesis and the reasons for prosthesis failure were divided into 7 categories and the main causes discussed. The overall MoMTHA revision rate was 4.7% after 6.9 years. MoMHRS revision rate was 5.9% after 5.7 years. The odds ratio was 1.25 (1.03:1.53) 95% CI (p = 0.03) (MoMHRS vs. MoMTHA).The studies of hip prostheses were separated into 2 categories of short- and long-term (more or less than 5 years). Short-term revision rate for MoMTHA was 4.5% after 4.8 years, and for MoMHRS 4.0% after 4.2 years. The odds ratio was 1.09 (0.82:1.43) 95% CI (0 = 0.56) (MoMTHA vs. MoMHRS). Long-term revision rate for MoMTHA was 5.2% after 7.7 years and 8.2% after 7.6 years for MoMHRS. The odds ratio was 1.58 (1.53:1.96) 95% CI (p = 0.0001) (MoMHRS vs. MoMTHA).Revision causes were divided into 7 main categories. The most common cause for revision for both MoMTHA and MoMHRS was loosening 47.6% vs. 37.7%, fracture (MoMTHA 7.69%; MoMHRS 19.62%), metal reactions (MoMTHA 7.69%; MoMHRS 26.92%) infection (MoMTHA 12.08%; MoMHRS 6.54%), instability (MoMTHA 9.13%; MoMHRS 2.69%), manufacturer defect 6.73% for MoMTHA and nonreported for MoMHRS, and miscellaneous (MoMTHA 7.69%; MoMHRS 6.54%) was stated.

INTERPRETATION

The comparison of MoMHRS and MoMTHA revision rates showed no difference in the short term, however in the longer term, the revision rate of MoMHRS was significantly higher than for MoMTHA. The linear increase in revision rate of MoMHRS may indicate a progression in failure.

Four-year results of Summit stems for total hip arthroplasty in Japanese patients

PURPOSE

A retrospective study to evaluate the clinical and radiographic outcome of the Summit primary total hip arthroplasty (THA) at a minimum follow-up of 4 years.

METHODS

87 hips in 84 Japanese patients underwent THA using Summit stems. 3 patients were lost to follow-up, and 4 patients were excluded because a Summit stem was judged to be inappropriate for their narrow femoral canals. The remaining 80 hips in 77 patients were evaluated. Mean age was 66 years (range, 33-86 y). Mean postoperative follow-up period was 52 months (range, 48-66 m).

RESULTS

There was no early stem subsidence after surgery. Of the 80 hips, 60 (75%) showed radiographic signs of stem osseointegration including zones 3 and 5 at final follow-up. Stress shielding occurred in 50 hips (62.5%), and third-degree stress shielding was observed in 12 hips (15%). 3 patients experienced postoperative thigh pain due to distal fixation.

CONCLUSIONS

These short-term results indicate that the Summit stem achieved good initial fixation, although there were some cases of distal fixation. Careful long-term follow-up and observation will be necessary for hips in which stress shielding occurs.

Birmingham hip resurfacing in patients who are seventy years of age or older

There is no published literature to support mid to long term results of hip resurfacing (HR) arthroplasty in patients over the age of 70 years. The purpose of our study was to evaluate the function HR in this age group (70 or older at the time of surgery) at medium to long term follow-up. Between July 1997 and November 2002, the Oswestry Outcome Centre independently and prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs). 106 had been implanted in elderly patients who were 70 years of age or older. The post-operative Harris and Merle D'Aubigné and Postel (MDP) hip scores and causes for revision were used to ascertain function and implant survival. Hip scores for the older BHR patients were compared with those from younger patients. The average age at surgery of the elderly BHR cohort was 73.2 years (range, 70.0 to 87.9 years) with a mean follow-up of 7.1 years (range, 0.5 to 10.9 years). Four patients had a femoral neck fracture and required conversion to a conventional total hip replacement. There were no patients lost to follow-up and no dislocations in this series. The median Harris hip score (HHS) was significantly better in the younger BHR group compared with the elderly BHR group, (96 vs. 94 p=0.008). There was no significant difference in recovery rates after surgery. There was a significantly higher rate of revision in women than men among the elderly patients (male= 1 of 65 (1.5%); women = 3 of 19 (15.8%), p=0.03). At latest follow-up the elderly patients continued to function well when compared with the younger BHR patients. There was a high mid to long term success rate after HR in patients who were 70 years of age or older, without the failure burden possibly anticipated. Elderly patients had a poorer functional outcome, but a difference in HHS of two points may be of only minor clinical significance.

Metal-on-metal hip resurfacing compared with total hip arthroplasty: two to five year outcomes in men younger than sixty five years

PURPOSE

There are limited studies examining the long-term survivorship for the current generation of metal-on-metal hip resurfacing (MOMHR) implants in the young male population, and fewer studies have been published on prospectively collected outcomes data for total hip resurfacing in the USA. The purpose of this study was to demonstrate the efficacy of MOMHR in comparison with total hip arthroplasty (THA) using validated outcome measures, survivorship and complication rates.

METHODS

The study prospectively followed 136 implants in 123 male patients <65 years, all with a primary diagnosis of osteoarthritis and similar comorbidities as determined by the American Society of Anesthesiologists (ASA) score. A single-surgeon cohort of 89 MOMHRs was compared with a similar cohort of 47 THAs. Outcomes were prospectively assessed with the Short-Form Health Survey of 12 questions (SF-12) and Western Ontario and McMaster Universities (WOMAC) questionnaires pre- and postoperatively at yearly intervals. Minimum follow-up was two years, and average follow-up was 3.9 years.

RESULTS

Diagnosis, body mass index (BMI), American Association of Anesthesiologists (ASA) and pre-operative pain and function scores were not significantly different between groups. There was no difference in SF-12 scores postoperatively. At one and two years postoperatively, the MOMHR group had better WOMAC scores than the THA group, but no difference was seen at three to five years postoperatively. There were no revisions in either group over the study period.

CONCLUSIONS

This study demonstrated good results for hip resurfacing in men <65 years five years postoperatively and similar function to THA patients.

Early failure of the Durom prosthesis in metal-on-metal hip resurfacing in Chinese patients

Hip resurfacing (HR) is being used increasingly as an alterative to total hip arthroplasty in osteonecrosis (ON) and ankylosing spondylitis (AS) of the hip. We performed 141 consecutive HR arthroplasties in 111 patients comprising 3 etiology groups: ON, AS, and osteoarthritis (OA). After retrospective study of retrieved components, we hypothesized that the main reason for revision was femoral loosening in the ON group (4 of 46 hips; 8.7%) and femoral-neck fracture in the AS group (3 of 58 hips; 5.2%). Necrotic areas were seen on femoral heads retrieved from patients with femoral loosening, whereas femoral heads were fixed tightly to components in patients with femoral-neck fractures. Etiology may be an important risk factor for postoperative complications.

Does the extent of osteonecrosis affect the survival of hip resurfacing?

BACKGROUND

The effect of the extent of osteonecrosis on the survival of hip resurfacing for osteonecrosis of the femoral head (ONFH) has not been well documented, but is a potentially important variable in the decision to perform resurfacing.

QUESTIONS/PURPOSES

We examined (1) the relationship between the volume of osteonecrosis in the femoral head before surgery and the extent of the residual necrotic bone after femoral head machining, (2) how the extent of the residual necrotic bone relative to the resurfaced femoral head (after femoral head machining) affected the survival of total hip resurfacing for patients with ONFH, and (3) how the extent of the necrotic bone relative to the entire femoral head (before femoral head machining) affected the survival and clinical outcome scores of patients who underwent total hip resurfacing.

METHODS

Thirty-three patients (39 hips) who underwent hip resurfacing were reviewed after a mean followup of 8 years. The extent of osteonecrosis in the femoral head and residual osteonecrosis in the implant bony bed after femoral head machining were estimated using a three-dimensional MRI-based templating system.

RESULTS

There was a statistically significant difference in the extent of osteonecrosis before and after femoral head machining, although the two were well correlated (r = 0.97). The mean percentage of osteonecrosis in the implant bony bed after femoral head machining was 5% smaller than that relative to the entire femoral head (range, -9% to 15%). There were no significant differences in implant survival between groups with small and large osteonecrosis classified by either the total amount of osteonecrosis before surgery or residual osteonecrosis after femoral head machining.

CONCLUSION

The extent of osteonecrosis in the femoral head significantly decreased after femoral head machining. Neither the residual osteonecrosis volume in the implant bony bed after femoral head machining nor the total amount of osteonecrosis before femoral head machining had significant influence on the survival of hip resurfacing.

Use of patient-specific templates in hip resurfacing arthroplasty: experience from sixteen cases

PURPOSE

Hip resurfacing arthroplasty (HRA) is a technically demanding operation, requiring both accuracy and precision in placement of the acetabular and femoral components. Malalignment of the component can lead to notching and possible femoral neck fractures. We used specific templates created using a rapid prototyping machine based on the patients' anatomy, to aid in accurate intraoperative pin placement.

METHODS

A 3D model of the hip was reconstructed using spiral computed tomography (CT) data by Amira 3.1 software in 16 patients in whom HRA was planned for hip osteoarthritis (OA). All of the patients in the study had normal contralateral hips. The rotational centre of femoral head on the normal side was superimposed using Imageware12.0 software to determine the centre of the femoral head on the contralateral side. The data was then used to produce patient-specific templates using a rapid prototyping technique. These templates were designed according to the anatomical features of femoral head surface, the rotation centre and the planned prosthesis shaft angle. The orientation of the prosthesis was determined by matching the model to the femoral head surface during the operation. In addition, a control group of 18 patients with OA was operated upon by the conventional method.

RESULTS

The mean prosthesis stem shaft angle (SSA), as determined from postoperative imaging, was 138.68 ± 8.85° for the locating template group, and (118.9 ± 12.8) for the conventional group.

CONCLUSIONS

The locating template designed and constructed preoperatively can provide precise and dependable location for hip resurfacing femoral components during arthroplasty and ensure the valgus stem placement necessary for optimal outcomes.

Patients report improvement in quality of life and satisfaction after hip resurfacing arthroplasty

BACKGROUND

A number of reconstructive procedures are available for the management of hip osteoarthritis. Hip resurfacing arthroplasty is now an accepted procedure, with implant survivorship comparable to THA at up to 10 years' followup in certain series. Most reports focus on implant survivorship, surgeon-derived results, or complications. Fewer data pertain to patient-reported results, including validated measures of quality of life (QoL) and satisfaction and baseline measures from which to determine magnitude of improvement. Validated patient-reported results are essential to guide patients and surgeons in the current era of informed and shared decision making.

QUESTIONS/PURPOSES

We determined whether patients reported improvement in disease-specific, joint-specific, and generic QoL after hip resurfacing arthroplasty; whether patients were satisfied with the results of the procedure; and latest activity level and return to sport.

METHODS

We retrospectively reviewed 127 patients (100 men, 27 women) who underwent 143 hip resurfacing procedures between 2002 and 2006. Mean patient age was 52 years. Patients completed the WOMAC, Oxford Hip Score, and SF-12 at baseline and again at minimum 2-year followup (mean, 2.5 years; range, 2-6 years). At latest followup, patients completed a validated satisfaction questionnaire and UCLA activity score.

RESULTS

All QoL scores improved (normalized to a 0-100 scale, where 100 = best health state). WOMAC improved from 46 to 95, Oxford Hip Score from 42 to 95, SF-12 (physical) from 34 to 54, and SF-12 (mental) from 46 to 56. Patient satisfaction score was 96. UCLA activity score was 8.

CONCLUSIONS

The majority of patients reported improvement in QoL, were very satisfied with their outcome, and returned to a high level of activity after hip resurfacing arthroplasty.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Do survival rate and serum ion concentrations 10 years after metal-on-metal hip resurfacing provide evidence for continued use?

BACKGROUND

Owing to concerns attributable to problems associated with metal-on-metal bearing surfaces, current evidence for the use of hip resurfacing is unclear. Survival rates reported from registries and individual studies are controversial and the limited long-term studies do not conclusively allow one to judge whether hip resurfacing is still a reasonable alternative to conventional THA.

QUESTIONS/PURPOSES

We asked whether the long-term survival rate of hip resurfacing is comparable to that of conventional THA and certain factors can be identified that influence serum ion concentration 10 years postoperatively. We specifically assessed (1) the 10-year survivorship in the whole cohort and in male and female patients, (2) serum concentrations of metal ions in patients with hip resurfacing who had not undergone revision surgery, and (3) potential influencing factors on the serum ion concentration.

METHODS

We retrospectively reviewed our first 95 patients who had 100 hip resurfacings performed from 1998 to 2001. The median age of the patients at surgery was 52 years (range, 28-69 years); 49% were men. We assessed the survival rate (revision for any reason as the end point), radiographic changes, and serum ion concentrations for cobalt, chromium, and molybdenum. The correlations between serum ion concentration and patient-related factors (age, sex, BMI, activity) and implant-related factors (implant size, cup inclination, stem-shaft angle) were investigated. The minimum followup was 9.3 years (mean, 10 years; range, 9.3-10.5 years).

RESULTS

The 10-year survivorship was 88% for the total cohort. The overall survival rate was greater in men (93%) than in women (84%). Median serum ion levels were 1.9 μg/L for chromium, 1.3 μg/L for cobalt, and 1.6 μg/L for molybdenum. Radiolucent lines around acetabular implants were observed in 4% and femoral neck thinning in 5%.

CONCLUSIONS

Although our overall failure rate was greater than anticipated, the relatively low serum ion levels and no revisions for pseudotumors in young male patients up to 10 years postoperatively provide some evidence of the suitability of hip resurfacing in this subgroup.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Socket position determines hip resurfacing 10-year survivorship

BACKGROUND

Modern metal-on-metal hip resurfacing arthroplasty designs have been used for over a decade. Risk factors for short-term failure include small component size, large femoral head defects, low body mass index, older age, high level of sporting activity, and component design, and it is established there is a surgeon learning curve. Owing to failures with early surgical techniques, we developed a second-generation technique to address those failures. However, it is unclear whether the techniques affected the long-term risk factors.

QUESTIONS/PURPOSES

We (1) determined survivorship for hips implanted with the second-generation cementing technique; (2) identified the risk factors for failure in these patients; and (3) determined the effect of the dominant risk factors on the observed modes of failure.

METHODS

We retrospectively reviewed the first 200 hips (178 patients) implanted using our second-generation surgical technique, which consisted of improvements in cleaning and drying the femoral head before and during cement application. There were 129 men and 49 women. Component orientation and contact patch to rim distance were measured. We recorded the following modes of failure: femoral neck fracture, femoral component loosening, acetabular component loosening, wear, dislocation, and sepsis. The minimum followup was 25 months (mean, 106.5 months; range, 25-138 months).

RESULTS

Twelve hips were revised. Kaplan-Meier survivorship was 98.0% at 5 years and 94.3% at 10 years. The only variable associated with revision was acetabular component position. Contact patch to rim distance was lower in hips that dislocated, were revised for wear, or were revised for acetabular loosening. The dominant modes of failure were related to component wear or acetabular component loosening.

CONCLUSIONS

Acetabular component orientation, a factor within the surgeon's control, determines the long-term success of our current hip resurfacing techniques. Current techniques have changed the modes of failure from aseptic femoral failure to wear or loosening of the acetabular component.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Resurfacing arthroplasty for hip dysplasia: a prospective randomised study

In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups. Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term.

Chinese experience with metal-on-metal hip resurfacing

The aim of this study was to study the actual clinical and laboratory results of metal-on-metal resurfacing hip arthroplasties by comparing with other implants. A total of 127 cases were operated on at the Department of Orthopaedics of Wuhan Union Hospital from 2005 to 2011. An important cause of failure is the fracture of the femoral neck. The chromium and cobalt levels of resurfacing hip arthroplasty and large-diameter head total hip arthroplasty (THA) are higher than those of a conventional metal-on-polyethylene total hip arthroplasty. There was a high ion level associated with an abduction angle of more than 45° and repetitive extreme hip motion in the 3 revision cases. The findings of this study are novel and quite controversial with that of the previously published literature.

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

PURPOSE

Hip resurfacing arthroplasty has gained popularity for treating young and active patients who have arthritis. There are two major data sources for assessing outcome and revision rate after total joint arthroplasty: sample-based clinical trials and national arthroplasty registers. The purpose of this study was to evaluate the outcome of the Birmingham Hip Resurfacing (BHR) arthroplasty in terms of revision rate as reported in clinical studies and recorded by national arthroplasty registers.

METHODS

A comprehensive literature research was performed from English-language, peer-reviewed journals and annual reports from national joint arthroplasty registers worldwide. Only publications from MEDLINE-listed journals were included. The revision rate was used as the primary outcome parameter. In order to allow for direct comparison of different data sets, calculation was based on revisions per 100 observed component years. For statistical analysis, confidence intervals (CI) were calculated.

RESULTS

A total of 18,708 implants, equivalent to 106,565 observed component years, were analysed in the follow-up studies. The register reports contained 9,806 primary cases corresponding to 44,294 observed component years. Statistical analysis revealed a significant difference in revisions per 100 observed component years between the development team (0.27; CI: 0.14-0.40) and register data (0.74; CI: 0.72-0.76).

CONCLUSION

The BHR arthroplasty device shows good results in terms of revision rate in register data as well as in clinical studies. However, the excellent results reported by the development team are not reproducible by other surgeons. Based on the results of our study, we believe that comprehensive national arthroplasty registers are the most suitable tool for assessing hip arthroplasty revision rate.

Hip resurfacing arthroplasty in inflammatory arthritis a 3- to 5-year follow-up study

The success of hip resurfacing in younger patients with primary osteoarthritis has paved the way for the trial of the procedure in patients with secondary osteoarthritis of the hip. We retrospectively reviewed the clinical and radiologic results in a cohort of 23 patients (32 hips) with inflammatory arthritis who were chosen for hip resurfacing after normalizing vitamin D levels and ruling out proximal femoral osteopenia using dual-energy x-ray absorptiometry. At a minimum follow-up of 3 years, there was failure in only 1 hip due to fracture of the femoral neck attributable to osteonecrosis of the remnant head. The clinical outcome was evaluated using Harris hip score and was found to be good to excellent in 30 of 31 hips. Hip resurfacing is a promising alternative in carefully chosen patients with inflammatory arthritis.

State of the art in hard-on-hard bearings: how did we get here and what have we achieved?

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Survival of hard-on-hard bearings in total hip arthroplasty: a systematic review

BACKGROUND

Improvements in prosthetic materials, designs, and implant fixation for THA have led to bearing surface wear being the limitation of this technology. Hard-on-hard bearings promise decreased wear rates and increased survival. However, there may be different survival rates based on bearing materials, manufacturing technologies, and femoral component designs. Additionally, survival rate variability may be based on study design.

QUESTIONS/PURPOSES

We determined survival rates and study levels of evidence and quality for the following bearings: stemmed metal-on-metal THA, metal-on-metal hip resurfacing, ceramic-on-ceramic THA, and ceramic-on-metal THA.

METHODS

We performed a systematic review of the peer-reviewed literature addressing THA hard-on-hard bearings. Quality for Level I and II studies was assessed.

RESULTS

The four Level I or II second-generation stemmed metal-on-metal THA studies reported between 96% and 100% mean survival at 38 to 60 months. The two Level I hip resurfacing studies reported 94% and 98% mean survival at 56 and 33 months. The four Level I studies of ceramic-on-ceramic THA reported survival from 100% at mean 51 months to 96% at 8 years.

CONCLUSIONS

While hard-on-hard bearing survival rates have generally been variable with earlier designs, contemporary implants have demonstrated survival of 95% or greater at followup of between 3 and 10 years. Some variability in survival may be due to differences in surgical technique, component positioning, and implant designs. As bearing designs continue to improve with modified materials and manufacturing techniques, use will increase, especially in young and active patients, though concerns remain about the increased reports of adverse events after metal-on-metal bearings.

Is resurfacing arthroplasty appropriate for posttraumatic osteoarthritis?

BACKGROUND

High survival has been reported for resurfacing arthroplasty in patients with femoral deformities. Also, hardware removal may not always be necessary with resurfacing arthroplasty and may eliminate some of the difficulties performing total hip arthroplasty (THA) in patients with posttraumatic osteoarthritis.

QUESTIONS/PURPOSES

We therefore asked: (1) are survivorship higher in patients who underwent resurfacing arthroplasty compared with patients with nontraumatic osteoarthritis; and (2) are those higher compared with all patients who have resurfacing?

METHODS

We identified 29 patients (29 hips) who had hip resurfacing for posttraumatic arthritis. These were compared with a matched cohort who had hip resurfacings for nontraumatic osteoarthritis and to all patients who underwent hip resurfacing for osteoarthritis during this time. The mean age was 47 years and mean body mass index was 27 kg/m(2). Survivorship and Harris hip scores were compared. Radiographs were evaluated for signs of radiolucencies, penciling, or osteolysis. The mean followup was 39 months (range, 24-99 months).

RESULTS

The 5-year survivorship was 90% in the posttraumatic group, 93% in the matched osteoarthritis group, and 97% in the entire osteoarthritis cohort. The mean Harris hip score for the posttraumatic group at last followup was 90 points. Other than the patients who underwent revision, we observed no radiographic radiolucencies or loosening in any of the groups.

CONCLUSIONS

The survival of resurfacing arthroplasty appears comparable to THA in posttraumatic osteoarthritis and for resurfacing in patients with osteoarthritis. Therefore, resurfacing may present an alternative treatment to THA in these patients.

Complications after metal-on-metal hip resurfacing arthroplasty

This article determines the incidence and cause of the complications commonly associated with metal-on-metal hip resurfacing implants and the proposed methods to prevent these complications. The literature available in PubMed was reviewed. Complication rates after hip resurfacing are low, and the procedure has shown both safety and efficacy in the hands of surgeons trained in specialized centers. Proper surgical technique can further reduce the incidence of femoral neck fracture, component loosening, and abnormal wear of the prosthesis. A more systematic detection of adverse local tissue reactions is needed to provide accurate assessments of their prevalence.

Metal-on-metal hip resurfacing: a critical review

In this article, a concise review of the current literature on metal-on-metal hip resurfacing (MoMHR) is given. In contrast to conventional total hip arthroplasty, older age, female sex and small femoral head sizes predispose to failure. Neck fracture and metal wear-related complications account for the most frequent reasons for re-operations. Although the long-term consequences of metal ion release remain unknown, the increasing prevalence of soft tissue related problems with potentially devastating functional consequences in this younger patient group are of concern. Outcome after revision for metal wear related failure of MoMHR is poor. In our opinion, patients with this device should be managed in dedicated centers with facilities for data collection and monitoring. The majority of proposed advantages of MoMHR cannot be supported by the published evidence.

Changes in cobalt and chromium levels after metal-on-metal hip resurfacing in young, active Chinese patients

Metal-on-metal resurfacing arthroplasty is increasingly being performed in young, active patients. Serum and urine metal ion levels are monitored in these patients to assess the physiologic effects of metal-on-metal wear on them. The aim of our prospective study was to evaluate the serum and urine levels of cobalt (Co) and chromium (Cr) in young (age, ≤50 years), active Chinese patients who had undergone metal-on-metal hybrid resurfacing arthroplasties. Levels were measured preoperatively using atomic absorption spectrometry and then sequentially at 3, 6, 9, 12, and 24 months after surgery. For both serum and urine Co and Cr, there was an initial increase to a peak at 6 months, followed by a gradual decline after 6 months, whereas renal function was normal during the study the 2-year study period. There was no radiographic evidence of component loosening. All implants were functioning well. Further long-term studies are needed to observe clinical outcomes and to determine the physiologic effects of the wearing process.

What is the midterm survivorship and function after hip resurfacing?

BACKGROUND

Hip resurfacing arthroplasty is a common procedure that improves functional scores and has a reported survivorship between 95% and 98% at 5 years. However, most studies are reported from the pioneering rather than independent centers or have relatively small patient numbers or less than five years followup. Various factors have been implicated in early failure.

QUESTIONS/PURPOSES

Our purposes were to determine: (1) the midterm survival of the BHR; (2) the function in patients treated with hip resurfacing; and (3) whether age, gender, BMI, or size of components related to failure.

METHODS

We reviewed the first 302 patients (329 hips) on whom we performed resurfacing arthroplasty. We assessed the survivorship, change in functional hip scores (HHS, OHS, WOMAC, UCLA), and analyzed potential risk factors (age, gender, BMI, component size) for failure. The mean age at the time of surgery was 56.0 years (range, 28.2-75.5 years). The minimum followup was 5 years (mean, 6.6 years; range, 5-9.2 years).

RESULTS

Kaplan-Meier analysis showed survival of 96.5% (95% CI, 94.7-98.4) at 9 years taking revision for any cause as the endpoint. All functional hip scores (HHS, OHS, WOMAC, UCLA) improved. Survivorship was higher in men compared with women. The component sizes and body mass index were smaller in the revised group compared with the nonrevised group.

CONCLUSIONS

Medium-term survivorship and functional scores of hip resurfacing are comparable to those from the pioneering center. Hip resurfacing remains a good alternative to THA, particularly in the younger male population with relatively large femoral head sizes.

Femoral-head vascularity after hip surface arthroplasty

BACKGROUND

iatrogenic devascularization of the femoral head is as an area of concern following hip resurfacing arthroplasty, with probable implications on short-term failure and long-term survival of the implant.

MATERIALS AND METHODS

we assessed the vascularity of 25 resurfaced femoral heads in 20 patients by comparison with preoperative and postoperative Tc-99m methylene diphosphonate (MDP) bone scintigraphy images, the postoperative scans being done 9 months after the surgery.

RESULTS

eight out of 25 hips (32%) showed <55% of their preoperative uptake at a mean of 9 months after surgery and were categorized as showing reduced vascularity.

CONCLUSION

our study reveals reduction in vascularity of the femoral-head remnant as a frequent occurrence after hip resurfacing. Our study also highlights the role of bone scintigraphy as tool in assessing the vascularity of resurfaced femoral heads.

Long-term survival and reason for revision of Wagner resurfacing hip arthroplasty

The long-term survival of 270 Wagner resurfacing hip arthroplasties was determined. Two patients were lost to follow-up. Eleven hips remained unrevised at 15 to 22 years. Survival at 5, 10, and 16 years was 74%, 35%, and 17%, respectively. Survival in patients older than 55 years was better after 5 years than that for patients 55 years or younger (P = .0067). Femoral neck fracture occurred in 2% of the total cohort. Femoral component failure was an early and midterm complication. Acetabular component loosening was the most common reason for revision. The proportion of cases revised for acetabular component failure increased with time. These long-term data in this large series provide important historical results against which the relative benefits of contemporary designs may be evaluated.

Morphologic analysis of periprosthetic fractures after hip resurfacing arthroplasty

BACKGROUND

Periprosthetic fractures have long been recognized as one of the major complications of hip resurfacing arthroplasty. The objective of this study was to develop a systematic and morphologic classification of the fracture mode based on pathogenesis.

METHODS

One hundred and seven retrieved specimens consisting of the femoral remnant and the femoral component of a total hip resurfacing arthroplasty that had failed as a result of a periprosthetic fracture were analyzed with regard to the morphologic failure mode. The location of the fracture line was used to differentiate the fractures. The fractures were also classified histopathologically as acute biomechanical, acute postnecrotic, or chronic biomechanical.

RESULTS

Fifty-nine percent (sixty-three) of the fractures occurred within the bone inside the femoral component. Fifty-one percent (fifty-five) of the fractures were classified morphologically as acute postnecrotic; 40% (forty-three), as chronic biomechanical; and 8% (nine), as acute biomechanical. Acute biomechanical fractures were found exclusively in the femoral neck and occurred earlier (mean time [and standard deviation] between implantation and revision, 41 +/- 57 days) than acute postnecrotic fractures (mean time between implantation and revision, 149 +/- 168 days; p = 0.002) or chronic biomechanical fractures (mean time between implantation and revision, 179 +/- 165 days; p = 0.001). The latter two fracture types both occurred predominantly in the bone inside the femoral component.

CONCLUSIONS

Three distinct fracture modes were characterized morphologically. Osteonecrosis was the most frequent cause of fracture-related failures. We suggest that an intraoperative mechanical injury of the femoral neck such as notching and/or malpositioning of the femoral component might lead to changes in the loading pattern or in the resistance to fracture of the femoral neck and may result in both acute and chronic biomechanical femoral neck fractures. These findings may serve as feedback information for the surgeon and possibly influence future therapeutic strategies.

Hip resurfacing arthroplasty for ankylosing spondylitis

We compared the results of the metal-on-metal hip resurfacing with the ceramic-on-ceramic total hip arthroplasty (THA) in 2 groups. The preoperative and postoperative ranges of motion (ROMs) were recorded. At the latest follow-up, both of the groups make satisfactory clinical and radiographic results. There was no significant difference in Harris hip score of the 2 groups, but the ROM of the hips in hip resurfacing group was significantly wider than THA group (P < .01). Hip resurfacing has better ROM improvement than THA, with the same pain relief. Its high stability and low dislocation rate allow patients to do early function exercises, which is important for ankylosing spondylitis (AS) patients to avoid reankylosis. Hip resurfacing may be a reasonable option for young AS population.

Resurfacing is comparable to total hip arthroplasty at short-term follow-up

Metal-on-metal total hip resurfacing arthroplasty has had excellent reported results at early to midterm followup, and some studies suggest that outcomes are comparable to conventional THA. We compared the clinical and radiographic outcomes of two closely matched groups of 54 patients who underwent resurfacing and conventional THA, respectively. Each group consisted of 36 men and 18 women who had a mean age of 52 years and a mean body mass index of 29 kg/m(2). At a minimum followup of 24 months (mean, 40 months; range, 24-60 months), the mean Harris hip scores increased similarly in both groups (from 52 to 90 points and from 50 to 91 points for the resurfacing and conventional groups, respectively). Radiographic outcomes, revision rates, complications, pain scores, and satisfaction ratings of the two groups were similar. The patients who underwent resurfacing had higher postoperative weighted activity scores than the patients who underwent conventional THA, although they had higher preoperative weighted activity scores as well. The early outcomes of resurfacing are comparable to those of conventional THA.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Is patient selection important for hip resurfacing?

The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration approval of two devices. Recent studies indicate satisfactory short- and midterm clinical results (1- to 10-year followup) with low complication rates, but there is a learning curve associated with this procedure, a more extensive surgical approach is necessary, and long-term results have yet to be determined. Proper patient selection may help avoid complications and improve patient outcomes. Patient selection criteria in the literature appear based predominantly on theoretical considerations without any consensus on stratifying patient risk. The most commonly reported complications encountered with hip resurfacing include femoral neck fracture, acetabular component loosening, metal hypersensitivity, dislocation, and nerve injury. At the time of clinical evaluation, patient age; gender; diagnosis; bone density, quality, and morphology; activity level; leg lengths; renal function; and metal hypersensitivity are important factors when considering a patient for hip resurfacing. Based on our review, we believe the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology.

LEVEL OF EVIDENCE

Level V, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Metal-on-metal hip resurfacing arthroplasty: a review of periprosthetic biological reactions

Metal-on-metal hip resurfacing arthroplasty has undergone a recent resurgence as an alternative treatment option for young and active patients with significant osteoarthritis. The claimed advantages of metal-on-metal hip resurfacing arthroplasty include lower wear rate, preservation of bone stock for subsequent revision procedures, restoration of anatomic hip mechanics, and enhanced stability due to the larger diameter of articulation. A disadvantage, however, is that the metal-on-metal resurfacing releases large amounts of very small wear particles and metal ions. The long-term biological consequences of the exposure to these Co-Cr particles and ions remain largely unknown. The purpose of this review is to provide an overview of the current literature on the adverse periprosthetic biological reactions associated with metal-on-metal hip resurfacing arthroplasty.

Metal-on-metal hip resurfacing in developmental dysplasia: a case-control study

Metal-on-metal hip resurfacing was performed for developmental dysplasia in 96 hips in 85 patients, 78 in women and 18 in men, with a mean age at the time of surgery of 43 years (14 to 65). These cases were matched for age, gender, operating surgeon and date of operation with a group of patients with primary osteoarthritis who had been treated by resurfacing, to provide a control group of 96 hips (93 patients). A clinical and radiological follow-up study was performed. The dysplasia group were followed for a mean of 4.4 years (2.0 to 8.5) and the osteoarthritis group for a mean of 4.5 years (2.2 to 9.4). Of the dysplasia cases, 17 (18%) were classified as Crowe grade III or IV. There were five (5.2%) revisions in the dysplasia group and none in the osteoarthritic patients. Four of the failures were due to acetabular loosening and the other sustained a fracture of the neck of femur. There was a significant difference in survival between the two groups (p = 0.02). The five-year survival was 96.7% (95% confidence interval 90.0 to 100) for the dysplasia group and 100% (95% confidence interval 100 to 100) for the osteoarthritic group. There was no significant difference in the median Oxford hip score between the two groups at any time during the study. The medium-term results of metal-on-metal hip resurfacing in all grades of developmental dysplasia are encouraging, although they are significantly worse than in a group of matched patients with osteoarthritis treated in the same manner.

Improved survivorship of hybrid metal-on-metal hip resurfacing with second-generation techniques for Crowe-I and II developmental dysplasia of the hip

BACKGROUND

The purpose of this study was to determine the influence of improved femoral fixation techniques on the survivorship of metal-on-metal total hip resurfacing prostheses in patients with developmental dysplasia of the hip and to report the long-term results of our patients managed earlier with first-generation fixation techniques.

METHODS

One hundred and three hips (ninety patients) were resurfaced for osteoarthritis secondary to developmental dysplasia. The mean age of the patients was forty-seven years, and 77% were women. Most hips (94%) were Crowe class I, but 43% had femoral head defects of >1 cm in size. The clinical results of these hips were compared with those of a group of patients with other etiologies, largely dominated by idiopathic osteoarthritis (78%).

RESULTS

All clinical scores improved significantly (p < 0.0001) and were comparable with those of patients with other etiologies except for the postoperative activity scores, which were lower (7.0 compared with 7.5). Range of motion was greater for the patients with dysplasia than for the patients with other etiologies. Seven hips that were resurfaced with the first-generation femoral fixation techniques and one hip that was resurfaced with the second and third-generation techniques had conversion to total hip arthroplasty. This difference was found to be significant (p = 0.032) in a multivariate, time-dependent analysis after adjustment for other covariates known to affect prosthetic survival. There was no loosening of the acetabular component in this series.

CONCLUSIONS

The current improvements in the short-term to midterm results after resurfacing in patients with developmental dysplasia of the hip in whom more current techniques were used are encouraging and allow for greater expectations regarding the elimination of short-term failures and improved long-term durability of resurfacing in this population.

Total hip resurfacing in patients who are sixty years of age or older

BACKGROUND

Metal-on-metal total hip resurfacing arthroplasty has been associated with excellent early results in patients who are younger than sixty years of age, but it remains controversial whether this procedure is appropriate in older patients. The purpose of the present study was to compare the clinical and radiographic outcomes after hip resurfacing in two cohorts of patients: those who were sixty years of age or older, and those who were younger than sixty years of age.

METHODS

Between November 2002 and August 2005, thirty-five patients (forty hips) who were sixty years of age or older were managed with metal-on-metal total hip resurfacing arthroplasty. The outcomes of these patients were compared with those of 130 patients (153 hips) who were younger than sixty years of age but otherwise had similar preoperative parameters and who had resurfacing arthroplasty performed during the same time interval and by the same surgeon. We evaluated Harris hip scores, Short Form-12 scores, and complications as well as radiographic alignment and radiolucencies.

RESULTS

At a mean follow-up time of thirty-six months, the mean Harris hip scores improved from 52 points to 94 points in the older patient cohort and from 53 points to 92 points in the younger patient cohort. The final Short Form-12 scores of the two groups were also similar. Two patients who were sixty years or older and five of the younger patients required conversion to a conventional total hip arthroplasty. Femoral neck fracture was the reason for one conversion in each group. There were no impending radiographic failures in either cohort.

CONCLUSIONS

Although national registries indicate that the risk of femoral neck fracture is higher in older patients, the present study found that these patients had excellent clinical outcomes that were similar to those of patients who were younger. We await longer follow-up results to determine further outcomes in these patients.

Metal-on-metal total hip resurfacing arthroplasty in the presence of extra-articular deformities or implants

BACKGROUND

Hip resurfacing has been proposed as an alternative to total hip replacement in patients who have proximal femoral deformities or retained hardware in the proximal aspect of the femur. In these situations, placement of a conventional stemmed hip prosthesis would be difficult or impossible, possibly necessitating a complex osteotomy or a custom prosthesis. The purpose of this study was to evaluate a series of patients who had extra-articular deformities of the proximal aspect of the femur and/or retained hardware and who were managed with a resurfacing hip prosthesis.

METHODS

Fifteen patients (seventeen hips) who underwent metal-on-metal resurfacing hip replacements were studied. Ten patients (twelve hips) had bowing or other deformities of the femur secondary to trauma, multiple epiphyseal dysplasia, renal osteodystrophy, or proximal femoral focal deficiency. Five patients (five hips) had retained hardware. Twelve of the patients (thirteen hips) had previously been told by orthopaedic surgeons that, due to the deformity or retained hardware, they could not undergo conventional total hip arthroplasty without also undergoing ancillary surgical procedures. We evaluated perioperative factors (operative time and estimated blood loss), Harris hip scores, complications, and failure rates.

RESULTS

At a mean follow-up time of three years (range, two to five years), fourteen patients (sixteen hips) were doing well clinically and radiographically. Assessment of the intraoperative records revealed minimal difficulty, with a mean operative time of 104 minutes and a mean blood loss of 621 mL. The mean Harris hip score was 92 points. One patient, a fifty-nine-year-old woman, underwent two subsequent revisions-one for the treatment of a femoral neck fracture, and one for the treatment of acetabular component loosening.

CONCLUSIONS

Resurfacing hip arthroplasty offers an option for patients when placement of a conventional total hip prosthesis is difficult or impossible because of the presence of proximal femoral deformities or retained hardware in or on the proximal aspect of the femur.

[Metal-on-metal hybrid hip resurfacing. Development and current state]

Worldwide the employment of surface replacements using metal-on-metal components as an option, particularly for the young and active patient, has gained broad acceptance. Part of the attraction for hip resurfacing is its conservative nature as a prosthetic solution for hip arthritis. It is anatomical, replicating the normal hip and limb length, preserving proximal femoral bone, and is a truly minimally bone invasive approach with excellent outcome of joint function. The purpose of this article is to show the data of 1,000 Conserve(c) Plus hybrid metal-on-metal prostheses in a consecutive study of 1,140 patients with a follow-up of 5.6 years. The current Kaplan and Meier survival estimates of the prosthesis, using any conversion to total hip replacement as the end point, were 98.1% at 3 years [95% confidence interval (CI): 96.8-98.9%], 96.7% at 4 years (95% CI: 94.8-97.8%), and 95.2% at 5 years (95% CI: 93.0-96.8%). The mean postoperative Harris hip score was 93.3. The current state of metal-on-metal surface replacement is positive. The new generation of hip resurfacing has a lot of improvements. The purpose of this review of the procedure is to point out the definite improvements from earlier designs using polyethylene as well as to highlight the overall results and durability achieved by one surgeon's extensive experience and to assess the results from other series and centers. We also want to point out the areas where further investigation is needed.

The five-year results of the Birmingham Hip Resurfacing arthroplasty

Few independent studies have reported the outcome of resurfacing arthroplasty of the hip. The aim of this study was to report the five-year clinical outcome and seven-year survival of an independent series.

A total of 610 Birmingham Hip Resurfacing arthroplasties were performed in 532 patients with a mean age of 51.8 years (16.5 to 81.6). They were followed for between two and eight years; 107 patients (120 hips) had been followed up for more than five years. Two patients were lost to follow-up. At a minimum of five years’ follow-up, 79 of 85 hips (93%) had an excellent or good outcome according to the Harris hip score. The mean Oxford hip score was 16.1 points (sd 7.7) and the mean University of California Los Angeles activity score was 6.6 points (sd 1.9). There were no patients with definite radiological evidence of loosening or of narrowing of the femoral neck exceeding 10% of its width. There were 23 revisions (3.8%), giving an overall survival of 95% (95% confidence interval 85.3 to 99.2) at seven years. Fractured neck of femur in 12 hips was the most common indication for revision, followed by aseptic loosening in four. In three hips (three patients) (0.5%), failure was possibly related to metal debris.

Considering that these patients are young and active these results are good, and support the use of resurfacing. Further study is needed to address the early failures, particularly those related to fracture and metal debris.

Hip resurfacing arthroplasty: the Australian experience

In the last 10 years, resurfacing hip arthroplasty has become a popular option again for treating hip disorders in younger, active patients in some parts of the world. We report the Australian experience with this operation based on the Australian National Joint Replacement Registry and the literature available on the Australian experience in Resurfacing.

[Surgical treatment of hip osteoarthritis: update in total hip arthroplasty]

Total hip replacement is one of the most successful procedures in orthopaedic surgery. There are two different technologies for implant fixation in total hip replacement: cemented and cementless, both can be combined, which is called Hybrid arthroplasty. Long term implant stability results in long term function. The most important factor that limits longevity of well-fixed implants is the wear of the articular surfaces. Wear of the polyethylene from the acetabulum generates particles that access the implant bone or the implant-cement-bone interface. This produces an inflammatory reaction, osteolysis and implant loosening. Polyethylene of higher resistance to wear and prosthetic articulations without polyethylene (hard on hard bearings), have been introduced to improve wear particle generation. Minimally invasive surgical techniques minimize surgical trauma to sort tissue around the hip joint, facilitating a better and more rapid recovery.