Low revision rate of dual mobility cups after arthroplasty for acute hip fractures: report of 11,857 hip fractures in the Dutch Arthroplasty Register (2007-2019)

Dual-Mobility Total Hip Arthroplasty in Patients with Obesity, Morbid Obesity and Super-Obesity: Medium-Term Outcomes of a Series of 180 Hips

Background

Obesity has been consistently proven to be associated with an increased risk of dislocation following total hip arthroplasty (THA). As the prevalence of obesity continues to rise globally, it is of vital importance to minimise risks, including dislocation rates, in these patients undergoing THA.

Methods

We describe a series of patients with obesity, morbid obesity (BMI ≥ 40) and super-obesity (BMI ≥ 50) undergoing THA at our institution over a 10-year period using a dual-mobility acetabular cup. The dislocation rate and all-cause revision rate were used as primary outcome measures. Patient-reported outcomes (PROMS) were assessed using the Oxford hip score (OHS) and VAS score. We assessed for differences in PROMS after grouping patients into BMI ranges of 30-34.9, 35-39.9, 40-49.9 and > 50.

Results

A total of 180 dual-mobility THAs in 162 patients were included of which 36 hips had BMI ≥ 40 and 8 hips had BMI ≥ 50. The mean age was 64.2 (29-88) years and the mean follow-up period was 52.1 months (13-122 months). The all-cause revision rate was 2.2% and no patient had a post-operative dislocation. The survivorship of the acetabular component was 100% with the maximum follow-up being 10.1 years. The mean OHS was 43.82 ± 3.29 (30-48) and the mean VAS for pain from the hip was 0.94 ± 1.34 (0-8). No significant difference in PROMS was found between the four BMI ranges.

Conclusion

Our results indicate excellent mid-term survivorship, and improvement over traditional dislocation rates in high BMI patients with a dual-mobility THA.

Femoral Neck Design Does Not Impact Revision Risk After Primary Total Hip Arthroplasty Using a Dual Mobility Cup

Background

The use of dual mobility (DM) cups has increased quickly. It is hypothesized that femoral neck taper geometry may be involved in the risk of prosthetic impingement and DM cup revision. We aim to (1) explore the reasons for revision of DM cups or head/liners and (2) explore whether certain femoral neck characteristics are associated with a higher risk of revision of DM cups.

Methods

Primary total hip arthroplasties with a DM cup registered in the Dutch Arthroplasty Register between 2007 and 2021 were identified (n = 7603). Competing risk survival analyses were performed, with acetabular component and head/liner revision as the primary endpoint. Reasons for revision were categorized in cup-/liner-related revisions (dislocation, liner wear, acetabular loosening). Femoral neck characteristics were studied to assess whether there is an association between femoral neck design and the risk of DM cup/liner revision. Multivariable Cox proportional hazard analyses were performed.

Results

The 5- and 10-year crude cumulative incidence of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was 0.5% (CI 0.4-0.8) and 1.9% (CI 1.3-2.8), respectively. After adjusting for confounders, we found no association between the examined femoral neck characteristics (alloy used, neck geometry, CCD angle, and surface roughness) and the risk for revision for dislocation, wear, and acetabular loosening.

Conclusions

The risk of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was low. We found no evidence that there is an association between femoral neck design and the risk of cup or head/liner revision.

Is outcome of total hip arthroplasty for hip fracture inferior to that of arthritis in a contemporary arthroplasty practice?

INTRODUCTION

Outcome of total hip arthroplasty (THA) for femoral neck fractures (FNF) has been associated with higher complication rates. However, THA for FNF is not always performed by arthroplasty-surgeons. This study aimed to compare THA outcomes for FNF to osteoarthritis (OA). In doing so, we described contemporary THA failure modes for FNF performed by arthroplasty surgeons.

METHODS

This was a retrospective, multi-surgeon study from an academic center. Of FNF treated between 2010 and 2020, 177 received THA by an arthroplasty-surgeon [mean age 67 years (range, 42 to 97), sex: 64.4% women]. These were matched (1:2) for age and sex with 354 THAs performed for hip OA, by the same surgeons. No dual-mobilities were used. Outcomes included radiologic measurements (inclination/anteversion and leg-length), mortality, complications, reoperation rates and patient-reported outcomes including Oxford Hip Score (OHS).

RESULTS

Post-operative mean leg-length difference was 0 millimeters (mm) (range, -10 to -10 mm), with a mean cup inclination and anteversion of 41 and 26° respectively. There was no difference in radiological measurements between FNF and OA patients (p=0.3). At 5 years follow-up, mortality rate was significantly higher in the FNF-THA compared to the OA-THA group (15.3 vs. 1.1%; p<0.001). There was no difference in complications (7.3 vs. 4.2%; p=0.098) or reoperation rates (5.1 vs. 2.9%; p=0.142) between groups. Dislocation rate was 1.7%. OHS at final follow-up was similar [43.7 points (range, 10 to 48) vs. 43.6 points (range, 10 to 48); p=0.030].

CONCLUSION

Total hip arthroplasty for the treatment of FNF is a reliable option and is associated with satisfactory outcomes. Instability was not a common reason of failure, despite not using dual-mobility articulations in this at-risk population. This is likely due to THAs being performed by the arthroplasty staff. When patients live beyond 2-years, similar clinical and radiographic outcomes with low rates of revision can be expected, comparable to elective THA for OA.

Dual-Mobility Cups in Primary Total Hip Arthroplasty

Dual-mobility cups (DMCs) were introduced in France more than 40 years ago and are increasingly used not only in hip revision but also primary hip arthroplasty. Due to a simulated large-head articulation and increased jumping distance, DMCs can contribute to a high range of motion in the hip joint and reduce the risk of instability. Numerous studies have reported low dislocation rates and high survival rates in the mid-term follow-up. Nevertheless, long-term data, especially on primary hip replacement, remain limited, and the effect of recent designs and material innovations is still unclear. Therefore, primary DMCs are mainly proposed in patients at high risk for dislocation (i.e. pelvitrochanteric insufficiency, compromised spinopelvic mobility, neuromuscular disorders, obesity and femoral neck fractures). Based on a review of recently published studies referring to these indications, the current study discusses the advantages and disadvantages of DMCs.

Use of dual-mobility cup in primary total hip arthroplasties: an Italian regional register (RIPO) study on three thousand, seven hundred and ten cases

PURPOSE

The purpose of the study was to investigate the outcome of dual-mobility cup (DM) compared with a standard cup (SC) in primary total hip arthroplasty (THA) in the long-term follow-up based on a regional Italian joint registry (RIPO).

METHODS

The Registry of Prosthetic Orthopaedic Implant (RIPO) was consulted, looking for all primary THAs implanted from 2000 to 2019. Three thousand seven hundred ten were dual-mobility cup (DM) total hip arthroplasties (THA) and 85.816 were standard cup (SC) THAs, on a total of 89.526 primary THA. Demographics, survival rates and causes of revision were evaluated and compared between the two groups.

RESULTS

The use of DM progressively increased from 0.4% in 2000 to 7.5% in 2018 of all primary THAs. Revision rate was 3.5% (128 on 3710) for DMC and 4.7% (4061 on 85,816) for SC. DM presented lower dislocation rate if compared to SC with 22-28-mm femoral head diameter. However, DM showed a higher risk of revision for any causes than SC with 32-mm femoral head diameter in long-term follow-up. Nevertheless, no significant difference was measured in terms of demographics and surgical approach for dislocation rate.

CONCLUSIONS

The DM cup represents a valid implant solution and has a lower dislocation rate than 22-28-mm SC. A slight increase in the use of DM implants over time was observed in the RIPO. However, a larger population and a longer follow-up are needed to further monitor the survival rate of new-generation DM implants.

Do Dual-mobility Cups Reduce Revision Risk in Femoral Neck Fractures Compared With Conventional THA Designs? An International Meta-analysis of Arthroplasty Registries

BACKGROUND

Dual-mobility cups in THA were designed to reduce prosthesis instability and the subsequent risk of revision surgery in high-risk patients, such as those with hip fractures. However, there are limited data from clinical studies reporting a revision benefit of dual-mobility over conventional THA. Collaboration between anthroplasty registries provides an opportunity to describe international practice variation and compare between-country, all-cause revision rates for dual-mobility and conventional THA.

QUESTIONS/PURPOSES

We summarized observational data from multiple arthroplasty registries for patients receiving either a dual-mobility or conventional THA to ask: (1) Is dual-mobility use associated with a difference in risk of all-cause revision surgery compared with conventional THA? (2) Are there specific patient characteristics associated with dual-mobility use in the hip fracture population? (3) Has the use of dual-mobility constructs changed over time in patients receiving a THA for hip fracture?

METHODS

Six member registries of the International Society of Arthroplasty Registries (from Australia, Denmark, Sweden, the Netherlands, the United Kingdom, and the United States) provided custom aggregate data reports stratified by acetabular cup type (dual-mobility or conventional THA) in primary THA for hip fracture between January 1, 2002, and December 31, 2019; surgical approach; and patient demographic data (sex, mean age, American Society of Anesthesiologists class, and BMI). The cumulative percent revision and mortality were calculated for each registry. To determine a global hazard ratio of all-cause revision for dual-mobility compared with conventional THA designs, we used a pseudoindividual patient data approach to pool Kaplan-Meier prosthesis revision data from each registry and perform a meta-analysis. The pseudoindividual patient data approach is a validated technique for meta-analysis of aggregate time-to-event survival data, such as revision surgery, from multiple sources. Data were available for 15,024 dual-mobility THAs and 97,200 conventional THAs performed for hip fractures during the study period.

RESULTS

After pooling of complete Kaplan-Meier survival data from all six registries, the cumulative percent revision for conventional THA was 4.3% (95% confidence interval [CI] 4.2% to 4.5%) and 4.7% (95% CI 4.3% to 5.3%) for dual-mobility THA at 5 years. We did not demonstrate a lower risk of all-cause revision for patients receiving dual-mobility over conventional THA designs for hip fracture in the meta-analysis once between-registry differences were adjusted for (HR 0.96 [95% CI 0.86 to 1.06]). A lower proportion of dual-mobility procedures were revised for dislocation than conventional THAs (0.9% versus 1.4%) but a higher proportion were revised for infection (1.2% versus 0.8%). In most registries, a greater proportion of dual-mobility THA patients were older, had more comorbidities, and underwent a posterior approach compared with conventional THA (p < 0.001). The proportion of dual-mobility THA used to treat hip fractures increased in each registry over time and constituted 21% (2438 of 11,874) of all THA procedures in 2019.

CONCLUSION

The proportion of dual-mobility THAs in patients with hip fractures increased over time, but there was large variation in use across countries represented here. Dual-mobility cups were not associated with a reduction in the overall risk of revision surgery in patients with hip fractures. A randomized controlled trial powered to detect the incidence of dislocation and subsequent revision surgery is required to clarify the efficacy of dual-mobility cups to treat hip fractures.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Dual mobility versus conventional total hip arthroplasty in femoral neck fractures (DISTINCT): protocol for a registry-nested, open-label, cluster-randomised crossover trial

INTRODUCTION

Hip fractures treated with total hip arthroplasty (THA) are at high risk of prosthesis instability, and dislocation is the most common indication for revision surgery. This study aims to determine whether dual mobility THA implants reduce the risk of dislocation compared with conventional THA in patients with hip fracture suitable to be treated with THA.

METHODS AND ANALYSIS

This is a cluster-randomised, crossover, open-label trial nested within the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The clusters will comprise hospitals that perform at least 12 THAs for hip fracture per annum. All adults age ≥50 years who meet the Australian and New Zealand Hip Fracture Registry guidelines for THA will be included. The intervention will be dual mobility THA and the comparator will be conventional THA. Each hospital will be allocated to two consecutive periods, one of dual mobility THA and the other of conventional THA in random order, aiming for an average of 16 patients eligible for the primary analysis per group (32 total per site), allowing different recruitment totals between sites. Data will be collected through the AOANJRR and linked with patient-level discharge data acquired through government agencies. The primary outcome is dislocation within 1 year. Secondary outcomes include revision surgery for dislocation and all-cause, complications and mortality at 1, 2 and 5 years. If dual mobility THA is found to be superior, a cost-effectiveness analysis will be conducted. The study will aim to recruit 1536 patients from at least 48 hospitals over 3 years.

ETHICS AND DISSEMINATION

Ethics approval has been granted (Sydney Local Health District - Royal Prince Alfred Hospital Zone (approval X20-0162 and 2020/ETH00680) and site-specific approvals). Participant recruitment is via an opt-out consent process as both treatments are considered accepted, standard practice. The trial is endorsed by the Australia and New Zealand Musculoskeletal Clinical Trials Network.

TRIAL REGISTRATION NUMBER

ACTRN12621000069853.

Hip stability parameters with dual mobility, modular dual mobility and fixed bearing in total hip arthroplasty: an analytical evaluation

Background

Use of dual mobility (DM) in total hip arthroplasty has gained popularity due to the ability to reduce dislocation through increased jumping distance and impingement-free arc of movement. Recently, modular dual mobility (modDM) systems were introduced to give the possibility to use DM with standard metal-backed shells, however few has been studied to date regarding how jumping distance and the center of rotation change with modDM. The objective of this study was to evaluate, through analytical simulation, how jumping distance, center of rotation and arc of movement change between DM and standard cups with modDM or fixed bearings (FB).

Methods

3D-models of DM and standard press-fit cups with modDM or FB liners were used to simulate DM, modDM and FB implant configurations, matched for same cup size, according to same cup position and different femoral head diameters. Jumping distance was calculated and center of rotation lateralization and oscillation angles were measured for each size of these three implant configurations.

Results

Jumping distance with modDM was reduced by -3.9 mm to -8.6 mm in comparison with DM, from 48 to 64 mm size, but resulted comparable to polyethylene 36 mm FB and increased by + 1.1 mm and + 1.4 mm than ceramic 36 and 40 mm FBs for sizes > 54 mm. ModDM lateralized the center of rotation up to + 2.5 mm and + 4.0 mm in comparison with DM and FBs, respectively. Oscillation angle with modDM resulted higher than + 16°, + 23°, + 17° and + 14° in comparison to DM, 28 mm, 32 mm and 36 mm FB cups, respectively, for 56 mm cup size.

Conclusions

According to its specific design, modDM might change hip stability parameters in comparison to DM, worsening jumping distance and center of rotation position, but increasing arc of movement. As not restoring stability parameters in the same fashion, modDM implants should be properly used when DM cups are not feasible.

Cost-effectiveness of dual-mobility components in patients with displaced femoral neck fractures

AIMS

Total hip arthroplasty (THA) with dual-mobility components (DM-THA) has been shown to decrease the risk of dislocation in the setting of a displaced neck of femur fracture compared to conventional single-bearing THA (SB-THA). This study assesses if the clinical benefit of a reduced dislocation rate can justify the incremental cost increase of DM-THA compared to SB-THA.

METHODS

Costs and benefits were established for patients aged 75 to 79 years over a five-year time period in the base case from the Canadian Health Payer's perspective. One-way and probabilistic sensitivity analysis assessed the robustness of the base case model conclusions.

RESULTS

DM-THA was found to be cost-effective, with an estimated incremental cost-effectiveness ratio (ICER) of CAD $46,556 (£27,074) per quality-adjusted life year (QALY). Sensitivity analysis revealed DM-THA was not cost-effective across all age groups in the first two years. DM-THA becomes cost-effective for those aged under 80 years at time periods from five to 15 years, but was not cost-effective for those aged 80 years and over at any timepoint. To be cost-effective at ten years in the base case, DM-THA must reduce the risk of dislocation compared to SB-THA by at least 62%. Probabilistic sensitivity analysis showed DM-THA was 58% likely to be cost-effective in the base case.

CONCLUSION

Treating patients with a displaced femoral neck fracture using DM-THA components may be cost-effective compared to SB-THA in patients aged under 80 years. However, future research will help determine if the modelled rates of adverse events hold true. Surgeons should continue to use clinical judgement and consider individual patients' physiological age and risk factors for dislocation. Cite this article: Bone Joint J 2021;103-B(12):1783-1790.

Total Hip Arthroplasty (THA) for Femoral Neck Fractures: Comparison between Standard and Dual Mobility Implants

The purpose of this retrospective study is to compare the short-term clinical and radiological results between standard and dual mobility THA for femoral neck fractures (FNF) in older patients. The hypothesis is that the dual mobility cup (DMC) has the same outcomes but a lower dislocation rate than the standard THA. The study population included 56 patients (mean age 77.7 years, range 71-85) that underwent THA for displaced FNF. Patients were divided in two comparable groups for baseline characteristics (age, sex and comorbidities): 28 patients underwent THA with a standard cup (SC) and 28 THA with DMCs. The clinical records and radiograms were reviewed to search relevant data in their postoperative history. Two postoperative dislocations occurred in the SC group and none in the DMC group. At an average follow up of 23 months (12-40), 48 patients were available for the final evaluation. The WOMAC score for all patients averaged 6.26 (0-46) and was slightly better in the DMC group (4.94 vs. 7.58; p-value = 0.41); scores were significantly better in presence of neurological comorbidities (p-value = 0.04), in the absence of diabetes (p-value = 0.04) and in the case of psychiatric disorders (p-value = 0.02). Radiographic evaluation at one year showed signs of osteointegration in 42/48 (87.5%) acetabular components (20 DMCs, 22 SC). According to our experience, DMCs proved to be a valid option for the treatment of displaced FNF in older patients, since it allowed them to achieve short-term outcomes comparable to conventional THA, while decreasing the incidence of postoperative dislocations.