Risk factors and modes of failure in the modern dual mobility implant. A systematic review and meta-analysis

Does-dual mobility still offer improved stability in smaller cup sizes? A computer modelling comparison of stability with 22-mm versus 28-mm inner heads in dual-mobility versus single-bearing constructs

PURPOSE

Dislocation remains 1 of the leading causes of revision after primary total hip arthroplasty (THA) and there is clear evidence the dual-mobility (DM) is used more frequently to minimise this. But in smaller cups, whether the use of DM with smaller 22-mm heads imparts any increased stability compared to standard bearing is unknown; especially when those smaller cups now allow for large single-bearing (SB) heads.

METHODS

3 primary cup sizes (48 mm, 50 mm, 52 mm) were chosen a priori for modelling. Head sizes trialled for the standard bearing (SB) constructs group were 28-0 mm, 32-0 mm and 36-0 mm against neutral polyethylene liners. In the modular sub-hemispheric DM constructs the inner head sizes for the DM constructs were altered where appropriate (22-0 mm vs. 28-0 mm). Cup position, stem offset, and stem size were standardised.

RESULTS

Both DM constructs outperformed all SB constructs because of a statistically significant jump distance increase (p < 0.001). However, there was no difference in range of motion (ROM) or jump distances between the 22-mm and 28-mm DM inner heads.The ROM angle before impingement between the DM (with 22-mm or 28-mm heads) and SB (with different head sizes where appropriate) showed no statistically significant difference. However, DM constructs presented significantly larger jump distances than SB constructs for both provocative dislocation tests across all 3 cup sizes.Of interest, for 50-mm and 52-mm cup sizes (for which this particular DM construct design can accommodate both 22-mm and 28-mm inner heads), there were no differences in ROM or jump distance between 22-mm versus 28-mm inner heads.

CONCLUSIONS

In this computer-modelling study, DM constructs are advantageous over SB constructs for improving jump distances in clinically provocative positions, but not range of motion angles. Inner head diameter of DM has no effect on stability.

Revision Dual Mobility Constructs With Unmatched Acetabular and Femoral Components Do Not Increase Failure Rate

BACKGROUND

Dual mobility (DM) constructs for revision total hip arthroplasty (THA) have continued to grow in popularity to mitigate instability. This benefit comes at the cost of potential unique modes of failure, and there are theoretical concerns that combining femoral and acetabular components from different manufacturers could lead to increased failure rates. We aimed to investigate rates of reoperation between matched and unmatched DM implants used in revision THA.

METHODS

We retrospectively reviewed 217 revision THAs performed with DM constructs between July 2012 and September 2021 at a single institution. Dual mobility (DM) constructs were classified as "matched" if the acetabular and femoral components were manufactured by the same company. They were classified as "unmatched" if the acetabular and femoral components were manufactured by different companies. The primary outcome was reoperation for any reason.

RESULTS

There were 136 matched DM constructs and 81 unmatched constructs. Average follow-up was 4.6 years (range, 2.0 to 9.6 years). There was no difference in reoperation rate between matched and unmatched groups (11.0 versus 13.6%, P = .576). The most common reasons for reoperation in both groups were instability and periprosthetic joint infection. There was 1 revision for intraprosthetic dislocation in the matched group.

CONCLUSIONS

The use of unmatched DM components in revision THA was common and did not increase the risk of reoperation at an average of 4.6-year follow-up. This information can be helpful in operative planning, but further research on long-term survival will be necessary.

Dual-Mobility Acetabular Components in Primary Total Hip Arthroplasty Do Not Increase the Risk of Complication Compared to Conventional Articulations: A Matched Cohort Comparative Analysis

Background

A recent National Joint Registry report suggests a higher local complication risk for dual-mobility (DM) total hip arthroplasty (THA) compared to conventional articulation THA. This report may be subject to data heterogeneity with multiple confounders. Controlling for these factors by matching demographic characteristics may give different results. We aim to compare 2-year local complication rates between matched DM and conventional THAs in primary hip osteoarthritis.

Methods

Data were collected for consecutive primary THAs undertaken via a posterior approach. The conventional articulation and DM cohorts were matched 3:1 for age, gender, American Society of Anesthesiology grade, body mass index, and operative time using a propensity score and nearest neighbor matching method. Outcome measures were 2-year local complication rates, reoperation rates, systemic complication rates, and mortality rates. Demographic and outcome data were compared, and cumulative survival rates (%) were assessed using Kaplan-Meier methodology with a 2-year local complication as the endpoint. Statistical significance was set at P < .05.

Results

Four hundred twelve THAs were included: 309 conventional and 103 DM articulations. There were no statistically significant differences between DM and conventional articulation THAs for local complications (7 [6.8%] vs 23 [7.4%], P = .820), reoperations (3 [2.9%] vs 4 [1.3%], P = .374), systemic complications (3 [2.9%] vs 4 [1.3%], P = .374), or 90-day mortality (1 [1%] vs 2 [0.6%], P = 1.000). Kaplan-Meier survival analysis demonstrated similar 2-year survival rates for conventional THAs compared to DM THAs (93.3% [standard error, 0.014] vs 91.9% [standard error, 0.031], P = .906).

Conclusions

This matched study shows that there is no difference in local complication rates between DM and conventional THA articulations.

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.

What is the rate of successful closed reduction of dislocated dual mobility cups following complex revision hip arthroplasty?

PURPOSE

The aim of this study was to assess the difference in success rates of closed reduction in septic and aseptic revision total hip arthroplasty (THA) performed with a dual mobility (DM) implant. Our objective was to answer the following questions: (1) Is there a difference in success rates of closed reduction between septic and aseptic revision THA with a DM implant? (2) Is closed or open reduction more successful in preventing re-dislocation?

METHODS

Between January 2009 and October 2021, 924 revisions were performed with a DM implant. All patients presenting to our institution with a dislocation following septic or aseptic revision THA using a cemented DM cup were included in this study. We analyzed 106 cases of dislocation in 74 patients. For all patients, we collected reason for revision, and classified index surgery as septic or aseptic.

RESULTS

Overall, 106 dislocations occurred (106/924, 11.5%). Thirty-nine cases (52.7%) had a dislocation after a septic exchange THA, while in 35 patients (47.3%), a dislocation occurred after an aseptic rTHA. In 29 patients (39.2%), successful closed reduction under general anesthesia was feasible, while the majority of cases required open reduction. In 31 of these patients (67.4%), open reduction was combined with a revision arthroplasty.

CONCLUSIONS

In case of DM cup dislocation, there is a low success rate of closed reduction. To prevent re-dislocation, total revision leads to a significantly reduced risk compared to open or closed reduction alone. Careful X-ray analysis for a halo sign showing intra-prosthetic DM cup dislocation is mandatory to avoid futile reduction attempts.

LEVEL OF EVIDENCE

III.

Survivorship of the dual-mobility construct in elective primary total hip replacement: a systematic review and meta-analysis including registry data

INTRODUCTION

Dislocation is a common complication associated with total hip replacement (THR). Dual-mobility constructs (DMC-THR) may be used in high-risk patients and have design features that may reduce the risk of dislocation. We aimed to report overall pooled estimates of all-cause construct survival for elective primary DMC-THR. Secondary outcomes included unadjusted dislocation rate, revision for instability, infection and fracture.

METHODS

MEDLINE, EMBASE, Web of Science, Cochrane Library and National Joint Registry reports were systematically searched (CRD42020189664). Studies reporting revision (all-cause) survival estimates and confidence intervals by brand and construct including DMC bearings were included. A meta-analysis was performed weighting series by the standard error.

RESULTS

Thirty-seven studies reporting 39 case series were identified; nine (10,494 DMC-THR) were included. Fourteen series (23,020 DMC-THR) from five national registries were included. Pooled case series data for all-cause construct survival was 99.7% (95% CI 99.5-100) at 5 years, 95.7% (95% CI 94.9-96.5) at 10 years, 96.1% (95% CI 91.8-100) at 15 years and 77% (95% CI 74.4-82.0) at 20 years. Pooled joint registry data showed an all-cause construct survivorship of 97.8% (95% CI 97.3-98.4) at 5 years and 96.3% (95% CI 95.6-96.9) at 10 years.

CONCLUSIONS

Survivorship of DMC-THR in primary THR is acceptable according to the national revision benchmark published by National Institute for Clinical Excellence (NICE).

Evolution and New Generation of Dual Mobility Cups

Although total hip arthroplasty (THA) is considered a successful procedure, hip dislocation remains the main cause of early failure. Dual mobility cups (DMCs) have been shown to significantly reduce the dislocation rate in both primary and revision THAs. During the past several decades, DMCs have evolved in design and fixation interface. There have been three generations of DMCs. This article addresses the rationale for a new cementless highly porous titanium DMC to improve component fixation and implant biocompatibility. [Orthopedics. 2023;46(5):e273-e280.].

Is Modular Dual Mobility Superior to Standard Bearings for Reducing Dislocation Risk after Primary Total Hip Arthroplasty? A Retrospective Comparative Multicenter Study

BACKGROUND

Dual mobility (DM) has been proven to reduce dislocation risk after total hip arthroplasty (THA). In the last decade modular DM (modDM) constructs have been introduced to allow the use of DM articulation with standard cementless acetabular shells. However, clinical evidence of modDM effectiveness is still low in primary THA and concerns about implant-related complications are increasing. This retrospective comparative multicenter study is aimed to investigate if the dislocation rate after primary THA could be reduced with modDM in comparison to standard bearing (SB).

METHODS

262 THAs were performed between 2017 and 2019, using SB (129 hips) or modDM (133) with the same cementless highly porous modular acetabular cup. Dislocations, complications and revisions were recorded and implant survival was analyzed.

RESULTS

At 2.5-year mean follow-up, dislocation occurred in 4 hips (3.1%) within the SB group while intraprosthetic dislocation in 2 hips (1.5%) within the modDM group (p = 0.44). Implant survivals with revision due to dislocation were 95.2% and 95.9% at 4-year follow-up for SB and modDM, respectively (p = 0.50).

CONCLUSIONS

modDM used in primary THA might reduce dislocation rate in comparison to SB, even in high-risk patients, however, caution is advocated due to specific intraprosthetic dislocation.

Mixed manufacturer dual mobility bearing and the Exeter V40 Stem: is it safe? Short-term results in primary and revision hip replacement

The aim is to review clinical and radiological outcomes for all cases of primary and revision THA, combining a cemented stem (Exeter V40) with a dual mobility component from a different manufacturer (SERF Novae), to evaluate whether concerns regarding mixing components from different manufacturers are justified. We identified 72 hip replacements performed between May 2010 and December 2015 using the SERF Novae dual mobility cup with an Exeter V40 stem, the majority of which were cemented (90%) and revisions (58%). Patients were evaluated clinically and radiologically at a minimum of two years. There were five (6.9%) dislocations; three (4.2%) requiring revision - one of which was an intra-prosthetic disarticulation and two infections. No cases were lost to follow-up and 49 surviving cases were reviewed at a mean of 4.0 (range 1.8-8.1) years following surgery. Pain and functional outcome scores all improved. There were no radiological failures and no revisions for aseptic loosening of stem or cup. The combination of Exeter cemented stem with a dual mobility bearing from a different manufacturer results in acceptable short-term outcomes in terms of hip stability, revision rates and patient-reported measures.

Dislocation and survival rate of dual mobility cups in revision total hip arthroplasty in patients with high risk of instability

PURPOSE

Instability remains as an unsolved complication after revision total hip arthroplasty (rTHA). Dual mobility (DM) cups have decreased dislocation rate in rTHA; however, there are few clinical studies that evaluate the risk of dislocation after rTHA in patients with high risk of instability.

METHODS

Between 2007 and 2019, 95 consecutive rTHA using a DM cup, in 93 patients with instability risk factors were retrospectively reviewed. Instability risk factors were defined as follows: deficient abductor mechanism (22.1%), previous dislocation (68.4%), Paprosky 3 acetabular bone defect (21.1%), neuromuscular disease (4.2%), lumbar spine arthrodesis (6.3%), and more than one previous surgery (33.6%). Mean follow-up was 4.3 ± 2.4 years. Clinical and radiographic parameters were reported. DM cup survival was determined using a Kaplan-Meier analysis with re-revision for any cause as the end-point. Surgical complications and re-dislocation rate was recorded.

RESULTS

Seven DM cups were re-revised; three due to aseptic loosening, three due to peri-prosthetic joint infection (PJI), and one due to instability. At seven years follow-up, the survival rate of the DM cup using re-revision for any reason as the end-point was 82.4% (95% confidence interval, 66.4-98.4%). There were 12 (12.6%) complications: two (2.1%) dislocations, six (6.3%) PJI, four (4.2%) peri-prosthetic fractures.

CONCLUSION

Our findings suggest DM cups are effective reducing dislocation rate in rTHA in patients with a high risk of instability, without increasing early aseptic loosening and with a low rate of dislocation. Nevertheless, longer follow-up is needed to confirm implant stability and dislocation rates in the long term.

Comparing dislocation rates by approach following elective primary dual mobility total hip arthroplasty: a systematic review

BACKGROUND

Dual mobility components can be implanted during total hip arthroplasty (THA) for primary osteoarthritis via a direct anterior approach (DAA), anterolateral approach (ALA), direct lateral approach (DLA), or posterior/posterolateral approach (PLA). This review compares dual mobility hip dislocation rates using these approaches for elective primary THA.

METHODS

PubMed, Embase, and Cochrane databases were systematically searched for articles published after January 1, 2006 that reported dislocation rates for adult patients after primary THA with dual mobility implants. Articles were excluded if they reported revision procedures, nonelective THA for femoral neck fractures, acetabular defects requiring supplemental implants, prior surgery, or ≤ 5 patients. The primary outcome was hip dislocation rate. Secondary outcomes included infection, Harris Hip Score (HHS), and Postel-Merle d'Aubigné (PMA) score.

RESULTS

After screening 542 articles, 63 met inclusion criteria. Due to study heterogeneity, we did not perform a meta-analysis. Eight studies reported DAA, 5 reported ALA, 6 reported the DLA, and 56 reported PLA. Study size ranged from 41 to 2,601 patients. Mean follow-up time ranged from 6 months to 25 years. Rates of infection and dislocation were low; 80% of ALA, 87.5% of DAA, 100% of DLA, and 82.1% of PLA studies reported zero postoperative dislocations. Studies reporting postoperative HHS and PMA scores showed considerable improvement for all approaches.

CONCLUSIONS

Patients undergoing primary THA with dual mobility implants rarely experience postoperative dislocation, regardless of surgical approach. Additional studies directly comparing DAA, ALA, DLA, and PLA are needed to confirm these findings.

Metal Articulations as a Source of Total Hip Arthroplasty Pain

The consensus systematic risk stratification algorithm from the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons, and The Hip Society summarizes clinical challenges in evaluation and treatment of metal-on-polyethylene total hip arthroplasty (THA) patients with adverse local tissue reaction (ALTR) due to mechanically assisted crevice corrosion (MACC), reviews up-to-date evidence, and identifies the areas for future research in order to provide a useful resource for orthopedic surgeons providing care to these patients. A painful THA has various intrinsic and extrinsic causes. ALTR is one of the intrinsic causes in patients with painful THA. The occurrence of ALTR due to MACC at modular junctions is likely to be multifactorial, including implant, surgical, and patient factors. Therefore, a systematic evaluation needs to involve a focused clinical history, detailed physical examination, laboratory tests, and imaging in order to identify potential differential diagnoses. There should be a low threshold to perform a systematic evaluation of patients with painful non-metal-on-metal THA, including patients with metal-on-polyethylene THA, and modular dual-mobility THA with the CoCr metal acetabular insert, as early recognition and diagnosis of ALTR due to MACC will facilitate initiation of appropriate treatment prior to significant adverse biological reactions. Specialized tests such as blood metal analysis and metal artifact reduction sequence magnetic resonance imaging are important modalities in evaluation and management of ALTR in patients with painful THA.

Treatment of Severe Acetabular Bone Loss Using a Tantalum Acetabular Shell and a Cemented Monoblock Dual Mobility Acetabular Cup

As the number of revision total hip arthroplasty increases, innovative solutions to complex problems are needed to address challenges posed by these complex cases. Severe acetabular bone loss, including cases of pelvic discontinuity, is a notable challenge with few solutions. Hip instability after revision arthroplasty remains one of the leading causes of revision and patient morbidity. The use of pelvic distraction and a press-fit tantalum shell for chronic discontinuity and posterior column open reduction and internal fixation with acetabular revision for acute pelvic discontinuity have previously been described. Similarly, dual mobility articulations have demonstrated long-term success in minimizing instability after revision total hip arthroplasty with good long-term survivorship. Here, the authors present a surgical technique in the management of Paprosky types 2 and 3 acetabular defects often with pelvic discontinuity using a tantalum shell in combination with cemented dual mobility liner to increase the stability of the joint. Custom screw placement is facilitated with the use of a metal cutting burr, both on the back table and in situ. The dual mobility liner is cemented, thus allowing for independent positioning of the acetabular implant and bearing surface. This technique has been successfully used in 19 patients with encouraging short-term results.

Early Intraprosthetic Dislocation After Closed Reduction in Modern Dual-mobility Total Hip Arthroplasty

The unique or specific implant-related complication of dual-mobility total hip arthroplasty (DM-THA) is intraprosthetic dislocation (IPD), and different mechanisms of IPD have been proposed. Early IPD or IPD without polyethylene wear has been reported in modern DM-THA designs. We report the first case of early IPD in Thailand that occurred after attempted closed reduction of DM-THA.