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

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

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

Metal-on-metal hip resurfacing arthroplasty provides excellent long-term survivorship and function in patients with a good-sized femoral head : results of a single, non-designer surgeon's cohort

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.

Methods

We reviewed 105 consecutive HRAs in 83 patients, performed by a single surgeon, at a mean follow-up of 14.9 years (9.3 to 19.1). The cohort included 45 male and 38 female patients, with a mean age of 49.5 years (SD 12.5)

Results

At the time of review 13 patients with 15 hips had died from causes unrelated to the hip operation, and 14 hips had undergone revision surgery, giving an overall survival rate of rate of 86.7% (95% confidence interval (CI) 84.2 to 89.1). The survival rate in men was 97.7% (95% CI 96.3 to 98.9) and in women was 73.4% (95% CI 70.6 to 75.1). The median head size of the failed group was 42 mm (interquartile range (IQR) 42 to 44), and in the surviving group was 50 mm (IQR 46 to 50). In all, 13 of the 14 revised hips had a femoral component measuring ≤ 46 mm. The mean blood levels of cobalt and chromium ions were 26.6 nmol/l (SD 24.5) and 30.6 nmol/l (SD 15.3), respectively. No metal ion levels exceeded the safe limit. The mean Oxford Hip Score was 41.5 (SD 8.9) and Harris Hip Score was 89.9 (14.8). In the surviving group, four patients had radiolucent lines around the stem of the femoral component, and one had lysis around the acetabular component; eight hips demonstrated heterotopic ossification.

Conclusion

Our results confirm the existing understanding that HRA provides good long-term survival and function in patients with adequate-sized femoral heads. This is evidenced by a 97.7% survival rate among men (larger heads) in our series at a mean follow-up of 14.9 years. Failure is closely related to head sizes ≤ 46 cm.

Cite this article: Bone Jt Open 2022;3(1):68–76.

Computational modelling of hip resurfacing arthroplasty investigating the effect of femoral version on hip biomechanics

Aim

How reduced femoral neck anteversion alters the distribution of pressure and contact area in Hip Resurfacing Arthroplasty (HRA) remains unclear. The purpose of this study was to quantitatively describe the biomechanical implication of different femoral neck version angles on HRA using a finite element analysis.

Materials and methods

A total of sixty models were constructed to assess the effect of different femoral neck version angles on three different functional loads: 0°of hip flexion, 45°of hip flexion, and 90° of hip flexion. Femoral version was varied between 30° of anteversion to 30° of retroversion. All models were tested with the acetabular cup in four different positions: (1) 40°/15° (inclination/version), (2) 40°/25°, (3) 50°/15°, and (4) 50°/25°. Differences in range of motion due to presence of impingement, joint contact pressure, and joint contact area with different femoral versions and acetabular cup positions were calculated.

Results

Impingement was found to be most significant with the femur in 30° of retroversion, regardless of acetabular cup position. Anterior hip impingement occurred earlier during hip flexion as the femur was progressively retroverted. Impingement was reduced in all models by increasing acetabular cup inclination and anteversion, yet this consequentially led to higher contact pressures. At 90° of hip flexion, contact pressures and contact areas were inversely related and showed most notable change with 30° of femoral retroversion. In this model, the contact area migrated towards the anterior implant-bone interface along the femoral neck.

Conclusion

Femoral retroversion in HRA influences impingement and increases joint contact pressure most when the hip is loaded in flexion. Increasing acetabular inclination decreases the area of impingement but doing so causes a reciprocal increase in joint contact pressure. It may be advisable to study femoral neck version pre-operatively to better choose hip resurfacing arthroplasty candidates.

Return to sports after hip resurfacing versus total hip arthroplasty: a mid-term case control study

BACKGROUND

Hip resurfacing (HR) is an alternative to conventional total hip arthroplasty (THA) for the treatment of osteoarthritis (OA) in very active, young male patients. However, there is no study in the literature that has proven its benefits for high-impact sport over standard primary THA. The aim of the current study was to investigate the return to sport and function level of male patients after THA vs. HR.

MATERIALS AND METHODS

This prospective study is based on a telephone questionnaire for general health and sports activities. 40 HRs were matched with 40 THAs based on preoperative University of California Arthroplasty Score (UCLA), BMI, age at time of surgery and age at follow-up. The mean follow-up period was 56 months (range 24-87 months).

RESULTS

HR patients showed a significantly higher High-activity arthroplasty score (HAAS) (14.9 vs. 12.9, p < 0.001) and Lower extremity activity scale (LEAS) (15.9 vs. 14.1, p < 0.001) and reached significantly higher values in the Hip cycle score (HCS) (44.7 vs. 35.7 p = 0.037) and Impact score (IS) (40.9 vs. 29.6, p < 0.002) than THA patients. No significant differences were found in the HOOS function section (91.4 vs. 90.3, p = 0.803) and the Pain numeric rating scale (NRS)-11 (0.6 vs. 0.9 p = 0.169). Patients with HR had a slightly higher Harris hip score (HHS) (97.8 vs. 95.6, p = 0.015) CONCLUSION: The current study suggests that young male patients are able to engage in higher activity levels after HR compared to standard THA.

Intraoperative Complications and Mid-Term Follow-Up of Large-Diameter Head Metal-on-Metal Total Hip Arthroplasty and Hip Resurfacing Arthroplasty

BACKGROUND AND AIMS

Large-diameter head total hip arthroplasty and hip resurfacing arthroplasty were popular in Finland from 2000 to 2012 for the treatment of hip osteoarthritis. The aim of this retrospective study was to investigate the mid-term survival of large-diameter head total hip arthroplasty patients operated on in three university hospitals and to compare these results to the survival of hip resurfacing arthroplasty patients.

MATERIAL AND METHODS

A total of 3860 hip arthroplasties (3029 large-diameter head total hip arthroplasties in 2734 patients and 831 hip resurfacing arthroplasties in 757 patients) were operated on between January 2004 and December 2009. The mean follow-up was 4.3 years (range: 0.3-8.0 years) in the total hip arthroplasty group and 5.1 years (range: 1.7-7.9 years) in the hip resurfacing arthroplasty group. Cox multiple regression model and Kaplan-Meier survival analysis were used to study the survival of the total hip arthroplasties and the hip resurfacing arthroplasties. Intraoperative complications and reasons for revisions were also evaluated.

RESULTS

In Cox regression analysis, the hazard ratio for revision of hip resurfacing arthroplasty was 1.5 compared with large-diameter head total hip arthroplasty (95% confidence interval: 1.0-2.2) ( p = 0.029). The cumulative Kaplan-Meier survival rate was 90.7% at 7.7 years for the large-diameter head total hip arthroplasty (95% confidence interval: 86.8-94.6) and 92.2% at 7.6 years for hip resurfacing arthroplasty (95% confidence interval: 89.9-94.6). There were a total of 166/3029 (5.5%) intraoperative complications in the large-diameter head total hip arthroplasty group and 20/831 (2.4%) in the hip resurfacing arthroplasty group ( p = 0.001). Revision for any reason was performed on 137/3029 (4.5%) of the arthroplasties in the large-diameter head total hip arthroplasty group and 52/831 (6.3%) in the hip resurfacing arthroplasty group ( p = 0.04).

CONCLUSION

The mid-term survival of both of these devices was poor, and revisions due to adverse reactions to metal debris will most likely rise at longer follow-up. There were more intraoperative complications in the large-diameter head total hip arthroplasty group than in the hip resurfacing arthroplasty group.

10-year results of the Birmingham Hip Resurfacing: a non-designer case series

INTRODUCTION

Recent controversies surrounding metal-on-metal (MoM) hip resurfacing has led to a substantial decline in its use. Despite this, there is good evidence to support the use of specific implants in select patients.

PATIENTS AND METHODS

A retrospective analysis of Birmingham Hip Resurfacing (BHR) patients with a minimum of 10 years follow-up was performed. Functional scoring was performed with the Oxford Hip Score (OHS) and failure was defined as revision for any cause. 111 patients underwent 121 BHR procedures. All patients had a minimum follow-up of 10 years. 70 patients (63%) were male. Mean patient age at surgery was 52.5 years (male 53.9 years, female 48.8 years).

RESULTS

Overall survival at 10 years was 91% (97% male, 80% female). There was a statistically significant improvement in OHS postoperatively which remains at 10-year follow-up (p = <0.05). There was no significant difference in scores between the male and female groups. Revisions were most often in patients with smaller component sizes but this was not found to be statistically significant.

CONCLUSIONS

Our results reflect that of the wider literature in that good outcomes can be obtained with this implant in a select group of patients and results are comparable to that of conventional hip arthroplasty in patients of a similar age.

Long-term Results of a First-Generation Annealed Highly Cross-Linked Polyethylene in Young, Active Patients

The survivorship of total hip arthroplasty in younger patients is dependent on the wear characteristics of the bearing surfaces. Long-term results with conventional polyethylene in young patients show a high failure rate. This study assessed the long-term results of a first-generation annealed highly cross-linked polyethylene (HCLPE) in uncemented total hip arthroplasty in young, active patients. Between 1999 and 2003, 112 total hip arthroplasty procedures performed in 91 patients with an average University of California Los Angeles activity score of 8 and mean age of 53 years (range, 24-65 years) were included from a prospective database. In all patients, a 28-mm metal femoral head on annealed HCLPE (Crossfire; Stryker, Mahwah, New Jersey) was used. At minimum 10-year follow-up (11.5±0.94 years), Kaplan-Meier survivorship was 97% for all failures (1 periprosthetic infection and 1 late dislocation) and 100% for mechanical failure (no revisions for osteolysis or loosening). This study showed low revision rates for wear-related failure and superior survivorship in young, active patients. Oxidation causing failure of the locking mechanism has not been a problem with Crossfire for up to 10 years.

The incidence of implant fractures after knee arthroplasty

PURPOSE

This study aimed to evaluate the incidence of "implant" fractures after knee arthroplasty using clinical literature and worldwide arthroplasty registers. The hypothesis was that register datasets report higher rates of these rare complications than clinical studies.

METHODS

Calculations were based on the pooled incidence of revision operations after fractures of knee arthroplasties, comparing clinical studies published in MEDLINE-listed journals and annual reports from worldwide arthroplasty registers in a structured literature analysis based on a standardized methodology.

RESULTS

Twelve clinical studies and datasets from six worldwide registers were included. Rates of fractures of knee arthroplasties were reported from 0.2 to 2.5 % in clinical studies versus 0.02-0.17 % in worldwide arthroplasty registers.

CONCLUSIONS

Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. Unicompartmental knee arthroplasty (UKA) implanted before 2000, constrained primary or revision constrained total knee arthroplasties, and patellar replacements showed the highest incidence of implant fracture. The results of this analysis can help clinicians to counsel patients on potential complications following knee arthroplasty.

LEVEL OF EVIDENCE

III.

Total hip replacement and surface replacement for the treatment of pain and disability resulting from end-stage arthritis of the hip (review of technology appraisal guidance 2 and 44): systematic review and economic evaluation

BACKGROUND

Total hip replacement (THR) involves the replacement of a damaged hip joint with an artificial hip prosthesis. Resurfacing arthroplasty (RS) involves replacement of the joint surface of the femoral head with a metal surface covering.

OBJECTIVES

To undertake clinical effectiveness and cost-effectiveness analysis of different types of THR and RS for the treatment of pain and disability in people with end-stage arthritis of the hip, in particular to compare the clinical effectiveness and cost-effectiveness of (1) different types of primary THR and RS for people in whom both procedures are suitable and (2) different types of primary THR for people who are not suitable for hip RS.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, The Cochrane Library, Current Controlled Trials and UK Clinical Research Network (UKCRN) Portfolio Database were searched in December 2012, with searches limited to publications from 2008 and sample sizes of ≥ 100 participants. Reference lists and websites of manufacturers and professional organisations were also screened.

REVIEW METHODS

Systematic reviews of the literature were undertaken to appraise the clinical effectiveness and cost-effectiveness of different types of THR and RS for people with end-stage arthritis of the hip. Included randomised controlled trials (RCTs) and systematic reviews were data extracted and risk of bias and methodological quality were independently assessed by two reviewers using the Cochrane Collaboration risk of bias tool and the Assessment of Multiple Systematic Reviews (AMSTAR) tool. A Markov multistate model was developed for the economic evaluation of the technologies. Sensitivity analyses stratified by sex and controlled for age were carried out to assess the robustness of the results.

RESULTS

A total of 2469 records were screened of which 37 were included, representing 16 RCTs and eight systematic reviews. The mean post-THR Harris Hip Score measured at different follow-up times (from 6 months to 10 years) did not differ between THR groups, including between cross-linked polyethylene and traditional polyethylene cup liners (pooled mean difference 2.29, 95% confidence interval -0.88 to 5.45). Five systematic reviews reported evidence on different types of THR (cemented vs. cementless cup fixation and implant articulation materials) but these reviews were inconclusive. Eleven cost-effectiveness studies were included; four provided relevant cost and utility data for the model. Thirty registry studies were included, with no studies reporting better implant survival for RS than for all types of THR. For all analyses, mean costs for RS were higher than those for THR and mean quality-adjusted life-years (QALYs) were lower. The incremental cost-effectiveness ratio for RS was dominated by THR, that is, THR was cheaper and more effective than RS (for a lifetime horizon in the base-case analysis, the incremental cost of RS was £11,284 and the incremental QALYs were -0.0879). For all age and sex groups RS remained clearly dominated by THR. Cost-effectiveness acceptability curves showed that, for all patients, THR was almost 100% cost-effective at any willingness-to-pay level. There were age and sex differences in the populations with different types of THR and variations in revision rates (from 1.6% to 3.5% at 9 years). For the base-case analysis, for all age and sex groups and a lifetime horizon, mean costs for category E (cemented components with a polyethylene-on-ceramic articulation) were slightly lower and mean QALYs for category E were slightly higher than those for all other THR categories in both deterministic and probabilistic analyses. Hence, category E dominated the other four categories. Sensitivity analysis using an age- and sex-adjusted log-normal model demonstrated that, over a lifetime horizon and at a willingness-to-pay threshold of £20,000 per QALY, categories A and E were equally likely (50%) to be cost-effective.

LIMITATIONS

A large proportion of the included studies were inconclusive because of poor reporting, missing data, inconsistent results and/or great uncertainty in the treatment effect estimates. This warrants cautious interpretation of the findings. The evidence on complications was scarce, which may be because of the absence or rarity of these events or because of under-reporting. The poor reporting meant that it was not possible to explore contextual factors that might have influenced study results and also reduced the applicability of the findings to routine clinical practice in the UK. The scope of the review was limited to evidence published in English in 2008 or later, which could be interpreted as a weakness; however, systematic reviews would provide summary evidence for studies published before 2008.

CONCLUSIONS

Compared with THR, revision rates for RS were higher, mean costs for RS were higher and mean QALYs gained were lower; RS was dominated by THR. Similar results were obtained in the deterministic and probabilistic analyses and for all age and sex groups THR was almost 100% cost-effective at any willingness-to-pay level. Revision rates for all types of THR were low. Category A THR (cemented components with a polyethylene-on-metal articulation) was more cost-effective for older age groups. However, across all age-sex groups combined, the mean cost for category E THR (cemented components with a polyethylene-on-ceramic articulation) was slightly lower and the mean QALYs gained were slightly higher. Category E therefore dominated the other four categories. Certain types of THR appeared to confer some benefit, including larger femoral head sizes, use of a cemented cup, use of a cross-linked polyethylene cup liner and a ceramic-on-ceramic as opposed to a metal-on-polyethylene articulation. Further RCTs with long-term follow-up are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013003924.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

[Registries as a tool for optimizing safety of endoprostheses. Experiences from other countries and the setup of the German arthroplasty register]

There has previously been no structured long-term documentation of the results of hip and knee prosthesis operations in Germany. This article presents the objectives, structure and data flow of the newly established German arthroplasty registry (EPRD). The EPRD is run as a subdivision of the German Society for Orthopedics and Orthopedic Surgery (Deutsche Gesellschaft für Orthopädie und orthopädische Chirurgie, DGOOC). It is dedicated to scientific principles and guarantees independency and immediate feedback to surgeons. The cooperation between insurance funds, hospitals, industry and scientific society is the key to success. Additional data acquisition and bureaucratic formalities are limited to a minimum and in particular there is no use of paper. Involving the health insurance funds provides access to relevant routine data. The implant documentation is facilitated by means of an implant library and barcode scanning in the operating room. The EPRD documents the survival of implants including the reasons for revision. Although the highest level of patient data protection is guaranteed, individual patients can be identified in case of implant recalls.

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

INTRODUCTION

Resurfacing as a percentage of total hip arthroplasty rose from 5.6 % in 2001 to 8.9 % in 2005 in Australia. During the same period the resurfacing to conventional prosthesis rose from 19.6 % to 29 % in the younger age group (less than 55 years). Long term (more than ten years) functional results of BHR are sparingly documented. Among the literatures available, the patient selection criteria vary from osteoarthritis, avascular necrosis, and dysplastic hip to slipped capital femoral epiphysis. The objective of the current study is to evaluate long term survivorship and functional outcome of Birmingham hip resurfacing surgery in osteoarthritic hip patients performed by a single surgeon.

PATIENTS AND METHODS

In this retrospective clinical study, all patients who underwent hip resurfacing for osteoarthritis of hip between 1999 and 2004 are included. All surgeries were performed by single surgeon (SJM) and in all patients Smith & Nephew system (Midland Medical Technologies, Birmingham, United Kingdom)) was used. Revision surgery is considered the end point of survivorship. Means, standard deviations, and confidence interval were calculated for all continuous measures. Survival analysis was performed with the Kaplan-Meier method and 95 % confidence intervals were calculated.

RESULT

The result is based on 222 patients (244 hips). This included 153 males and 69 females. Our mean follow up was 12.05 years and overall survival was 93.7 %. In terms of gender, survival in males was 95.43 % while in females it was 89.86 %. Failure was seen in 14 patients (16 hips), which included seven female (10.14 %) and seven male (4.57 %) patients. Failure of femoral components due to aseptic loosening and varus collapse was seen in eight patients after a mean 9.6 years. Metal allergy was seen in three patients (five hips), all of them were female of which two had bilateral resurfacing. Other complications included femoral neck stress fractures in two patients and acetabular component loosening in one patient. We observed that the failure rate is higher if the BHR femoral component size is 46 or less (ten out of 16 hips revised).

CONCLUSION

If patient selection is judiciously done and surgical technique is meticulously followed, hip resurfacing offers acceptable survivorship, satisfactory range of motion and enables patients to resume high demand activities including sports. Future improvements in the bearing surfaces, and possibly in the design, might alleviate concerns posed by high serum metal level and provide options that continue to benefit younger patients in future.

Outcome of Birmingham hip resurfacing at ten years: role of routine whole blood metal ion measurements in screening for pseudotumours

PURPOSE

Emerging concern has arisen because of recent papers reporting a high prevalence of pseudotumours (PTs), even in patients with surface arthroplasties with a good clinical track record. The aim of our study was to establish the ten year survivorship of Birmingham hip resurfacing (BHR), to investigate whole blood (WB) metal ion levels and prevalence of adverse reactions to metal debris (ARMeD) and to determine the association of blood metal ion levels and symptoms with ARMeD in patients operated on with BHR at our institution.

METHODS

Between May 2001 and May 2004, 261 consecutive BHRs were implanted in 219 patients. All living, nonrevised patients underwent a systematic screening programme consisting of clinical examination, WB cobalt and chromium measurements and targeted cross-sectional imaging.

RESULTS

The ten year survival for the entire cohort was 91% (89-93%), with any revision as the endpoint. Prevalence of ARMeD was 6.9% in male and 8.8% in female patients. Symptomatic patients with elevated metal ion levels evinced highest prevalence (63%) of PTs compared with asymptomatic patients with elevated metal ion levels (42%) and symptomatic patients with nonelevated metal ions (11%).

CONCLUSIONS

Contradicting the current international guidelines, our results suggest that it seems beneficial to combine routine metal ion measurement with clinical assessment, even in patients with well-functioning BHRs. Further follow-up will reveal whether new PTs will develop in these patients and BHR survivorship in the longer term.

Survival and functional outcome of the Birmingham Hip Resurfacing system in patients aged 65 and older at up to ten years of follow-up

PURPOSE

Limited evidence exists regarding the outcomes of hip resurfacing in elderly patients. The primary study aims were to determine the survival and functional outcome following Birmingham Hip Resurfacing (BHR) in patients ≥65 years at up to ten years of follow-up. Secondary aims were to explore factors affecting survival and functional outcome.

METHODS

Between 1997 and 2012, data were prospectively collected on 180 BHR (162 patients; mean age 69.2 years; 62 % male) implanted by one designing surgeon. Mean follow-up was six (range one to 14.4) years with no loss to follow-up. Outcomes of interest were implant survival, functional outcome [Oxford Hip Score (OHS)] and radiological evidence of implant failure.

RESULTS

Three hips were revised, giving an overall cumulative survival of 96.4 % [95 % confidence interval (CI) 90.3-100] at ten years. Survival of 111 male BHR was 98.9 % (95 % CI 94.8-100) at ten years (one revision) compared with 91.9 % (95 % CI 77.0-100) in 69 female BHR (two revisions). Survival was affected by age (p = 0.014) and femoral head size (p = 0.024) but not by gender (p = 0.079). Median pre-operative OHS was 50.0 % [interquartile range (IQR) 37.5-68.8], improving to 4.4 % (IQR 0-10.4) postoperatively. Men had significantly better postoperative OHSs compared with women (median male OHS 2.1 % versus 6.3 % female OHS; p = 0.021).

CONCLUSIONS

Good survival and functional outcomes were achieved with the BHR at ten years in men and women ≥65 years. Despite registry findings to the contrary, age alone should not be a contraindication for hip resurfacing in centres with expertise in this procedure.

Systematic review on outcomes of acetabular revisions with highly-porous metals

PURPOSE

The purpose of this study was to systematically review the literature and report the clinical and radiographic outcomes of highly-porous acetabular cups in revision settings.

METHOD

A literature search of four electronic databases of EMBASE, CINAHL-plus, PubMed, and SCOPUS yielded 25 studies reporting the outcomes of 2,083 revision procedures with highly-porous acetabular components. There was lack of high quality evidence (level I and level II studies) and only two studies with level III evidence, while the remainder were all level IV studies. In addition, a majority of the studies had small sample sizes and had short to mid-term follow-up. The mean age of the patients was 65 years (range, 58-72 years) and the mean follow-up was 3.6 years (range, two to six years). Outcomes evaluated were aseptic survivorship, Harris hip scores, migration rates, incidence of peri-acetabular radiolucencies and radiographic restoration of the hip centre.

RESULTS

The mean aseptic survivorship was 97.2% (range, 80-100%). The Harris hip scores improved from a mean pre-operative score of 42 points, (range, 29-75 points), to a mean postoperative score of 79 points (range, 69-94 points). The mean incidence of cup migration and prevalence of peri-acetabular radiolucencies was 2.4% (range, 0-8.8%) and 4.6% (range, 0-19%), respectively, at final follow-up. The vertical hip centre-of-rotation was restored significantly from a mean of 39.2 mm (range, 27.6-50 mm) pre-operatively, to a mean of 24.1 mm (range, 7.4-47 mm), postoperatively.

CONCLUSION

The short-term clinical and radiographic results of highly-porous metals in revision hip arthroplasty are excellent with a low rate of loosening in the presence of both major and minor bone loss.

Revision surgery after total joint arthroplasty: a complication-based analysis using worldwide arthroplasty registers

The authors performed a complication-based analysis of total knee (TKA), total hip (THA), and total ankle arthroplasty (TAA) using worldwide arthroplasty registers. We extracted data with respect to reason for revision surgery and pooled causes. The most common causes for revisions in THA were aseptic loosening (55.2%), dislocation (11.8 %), septic loosening (7.5%), periprosthetic fractures (6%), and others. The most common causes in TKA were aseptic loosening (29.8%), septic loosening (14.8%), pain (9.5%), wear (8.2%), and others. The most common causes in TAA were aseptic loosening (38%), technical errors (15%), pain (12%), septic loosening (9.8%), and others. Revisions in TKA and THA differ with respect to type of complication. However, in case of TAA, higher rates of technically related complications are reported.

The Canadian Arthroplasty Society’s experience with hip resurfacing arthroplasty

The purpose of this study was twofold: first, to determine whether the five-year results of hip resurfacing arthroplasty (HRA) in Canada justified the continued use of HRA; and second, to identify whether greater refinement of patient selection was warranted.

This was a retrospective cohort study that involved a review of 2773 HRAs performed between January 2001 and December 2008 at 11 Canadian centres. Cox’s proportional hazards models were used to analyse the predictors of failure of HRA. Kaplan–Meier survival analysis was performed to predict the cumulative survival rate at five years. The factors analysed included age, gender, body mass index, pre-operative hip pathology, surgeon’s experience, surgical approach, implant sizes and implant types. The most common modes of failure were also analysed.

The 2773 HRAs were undertaken in 2450 patients: 2127 in men and 646 in women. The mean age at operation was 50.5 years (sd 8.72; 18 to 82) and mean follow-up was 3.4 years (sd 2.1; 2.0 to 10.1). At the last follow-up a total of 101 HRAs (3.6%) required revision. Using revision for all causes of failure as the endpoint, Kaplan–Meier survival analysis showed a cumulative survival of 96.4% (95% confidence interval (CI) 96.1 to 96.9) at five years. With regard to gender, the five-year overall survival was 97.4% in men (95% CI 97.1 to 97.7) and 93.6% in women (95% CI 92.6 to 94.6). Female gender, smaller femoral components, specific implant types and a diagnosis of childhood hip problems were associated with higher rates of failure. The most common cause of failure was fracture of the femoral neck, followed by loosening of the femoral component.

The failure rates of HRA at five years justify the ongoing use of this technique in men. Female gender is an independent predictor of failure, and a higher failure rate at five years in women leads the authors to recommend this technique only in exceptional circumstances for women.

Cite this article: Bone Joint J 2013;95-B:1044–50.

[Revision rates in journal publications on joint prostheses with noticeably high failure rates in register data sets]

BACKGROUND AND AIM OF STUDY

The value of outcome quality data from clinical studies is an issue of controversial debate particularly in the context of adverse events. The aim of this study is to present and evaluate the data available from clinical studies for products that show inferior outcome in registers and to assess the possibility to draw valid conclusions from these data. STUDY DESIGN AND ANALYTICAL METHODS: Based on a structured literature research, a comparative analysis was made of the revision rates of 12 products showing significantly inferior average results in registers. The primary outcome parameter was the revision rate for any reason calculated using a standardized methodology and the parameter of revisions per 100 observed component years.

RESULTS

For 5 out of 12 products not a single comparable study was available and relatively few data were available for the remaining products. A conventional meta-analysis revealed that only three products showed results that were comparable with those from registers. For 75% of products good results were published. There was not a single case where it would have been possible to identify or isolate the problems that had led to the underperformance observed on the basis of clinical studies alone.

DISCUSSION

Clinical sample-based studies are not a suitable and reliable means to recognize potential product or handling problems and avoid risks for patients and physicians. In this respect registers can provide an essential contribution.

Can patients return to high-impact physical activities after hip resurfacing? A prospective study

PURPOSE

Although the resumption of low-impact sports activities is compatible with total hip arthroplasty (THA), participation in high-impact sports seems problematic, and there is no consensus as to whether it is advisable. The purpose of this article is to evaluate the quality and possibility of resuming high-impact physical activities after hip resurfacing.

MATERIALS

The study was performed in an on-going, single-surgeon, prospective series of 215 resurfacing arthroplasties (RSA). Mean follow-up was 44.1 months (range, 39.1-54.5). Clinical evaluation included the Postel-Merle d'Aubigné (PMA) score, the Oxford hip score, the Harris hip score (HHS), Devane score, and UCLA activity score. A specific questionnaire analysing sports activities was administered to each patient to assess the number and level of physical activities performed (both before the operation and at final follow-up).

RESULTS

In the series of 202 consecutive patients (215 RSA), 50 patients (55 RSA) engaged regularly in at least one high-impact activity before their operation and the onset of pain, 102 patients practised at least one intermediate-impact activity, and the 50 remaining patients undertook only low-impact activities. Harris hip score increased from 44.8 (range, 23-68) before the operation to 97.8 (range, 85-100) at the last follow-up. Mean time to sports resumption after surgery was 14.6 weeks (range, 7-29). The resumption rate was 98 % for sports of any impact level and 82 % for high-impact activities. No osteolysis or implant loosening was observed at follow-up. No revision was performed.

CONCLUSION

In 2012, no consensus recommendations yet exist for the resumption of sports activities after RSA. Existing recommendations concern only conventional THA. We believe that RSA allows younger and more active patients to resume physical and sports activities without restriction. The rate of return to sports after RSA appears to be excellent and unequalled by conventional hip prostheses. High-impact sports seem to be compatible with hip resurfacing, although no long-term studies have analysed the impact of these activities on wear and/or aseptic loosening.

Application and survival curve of total hip arthroplasties: a systematic comparative analysis using worldwide hip arthroplasty registers

PURPOSE

The aim of the study was to compare primary total hip arthroplasty (THA) implantations between different countries in terms of THA number per inhabitant, age, and procedure type and to compare the survival curve including all THAs using hip arthroplasty registers.

METHODS

THA registers were compared between different countries with respect to the number of primary implantations per inhabitant and age, procedure type and survival curve. We performed a literature search for all national hip arthroplasty registers providing annual reports for 2009 or, if not available, a more recent period. The data from these reports were analysed in terms of number, age distribution and procedure type of primary THAs and survival curves.

RESULTS

We identified nine hip arthroplasty registers, which comprised sufficient data to be included. A large variation was found in the annual number of primary THA implantations per inhabitant. The procedure type varied greatly as well, e.g. in Sweden 67 % are cemented THAs whereas in Emilia-Romagna (Italy) 89 % are cementless THAs.

CONCLUSIONS

This study revealed large differences in terms of the annual number of primary THAs per inhabitant and primary THA procedure type across countries. These data can be used to rank local primary THA implantations within an international context.