Dual Mobility Liner Research Articles

Cementation of a Metal Dual Mobility Liner in Patients Undergoing Revision Total Hip Arthroplasty

BackgroundDual mobility liners for primary and revision total hip arthroplasties can lead to decreased dislocation and revision rates. However, there are a lack of data analyzing their utilization when cementing into well-fixed acetabular components in a variety of scenarios. Therefore, the purpose of this study was to examine cementation of dual mobility liners into well-fixed existing acetabular components from previous hip procedures, into new acetabular components, or directly into the acetabulum without prior implants. We specifically aimed to assess the following: (1) aseptic revision-free implant survivorship, (2) patient-reported outcomes, (3) prosthetic joint infections, dislocations, and osteolysis, (4) medical complications and readmissions, and (5) radiographic outcomes. MethodsA total of 35 patients who underwent treatment with a cemented dual mobility liner from October 1, 2014, to July 1, 2018, were identified and followed up for a mean of 4 years (range, 4-8). The primary outcome of interest was revision-free survival. The secondary outcomes included patient-reported outcome measurements, dislocations, periprosthetic infections, periprosthetic fractures, pulmonary emboli, deep vein thromboses, radiographic osteolysis, and emergency visits as well as inpatient admissions. The patient-reported outcome measurements used were the Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, Short-Form 12 Health Survey Mental Component, and Short-Form 12 Health Survey Physical Component. ResultsAseptic revision-free survivorship was 93.3%, 92.3%, and 100% for previous acetabular cup, new cup, and native acetabulum, respectively. The Hip Disability and Osteoarthritis Outcome Score for Joint Replacement improved and the Short-Form 12 Physical Component improved postoperatively for all groups. Surgical complications included 3 prosthetic joint infections (1 in a new cup and 2 in native acetabula). A total of 1 patient (previous cup) had an emergency visit and inpatient readmission. Only 1 cemented dual mobility recipient (new cup) demonstrated progressive acetabular radiolucencies and all cemented dual mobility patients had no evidence of acetabular subsidence. ConclusionsCemented dual mobility bearing liners demonstrated exceptional survivorship, low complication rates, adequate radiographic results, and improved functional outcomes when cemented into previously inserted well-fixed acetabular components, new components, or native acetabula. To the best of the authors’ knowledge, this is the first study to demonstrate success at a minimum of 4-year follow-up. These data are important to surgeons deciding on the appropriate implantation methods to use for their high-risk patients.

Single center evaluation of outcomes of modular dual mobility liners during revision total hip arthroplasty: A five-year follow-up

IntroductionRevision total hip arthroplasty (rTHA) is at increased risk for postoperative instability when compared to primary cases, which has been mitigated to some extent with the introduction of dual mobility (DM) reconstructions. These constructs were designed to lower dislocation rates and to improve impingement-free range of motion. As a follow-up to our prior institutional study, we expanded on a cohort of DM reconstructions compared to non-DM constructs. We examined a modular dual mobility system in rTHA to measure loosening of the acetabular component, as well as revision and dislocation rates in comparison to an historical cohort of single articulation prostheses.Materials/Methods: This retrospective cohort study from a single center included 254 patients who underwent rTHA with a dual mobility liner by three fellowship-trained surgeons between January 1, 2014 and December 1, 2019. This was a follow-up to an historical cohort of revisions performed with a single articulation prosthesis (n = 120) from the same surgeons performed between January 1, 2011 and December 23, 2013. The inclusion criteria included consecutively performed rTHAs that had a minimum follow-up of 2 years. We excluded patients who had femoral revisions and head/liner revisions only. The average follow-up in the dual mobility cohort and the single articulation cohort was 5 years (range, 2–10 years) and 2.5 years (range, 1.5–4.3 years), respectively. The primary outcomes were dislocation, aseptic loosening, and re-revision rates. Secondary outcomes were radiographic analyses of cup migration and osteolysis. ResultsThere were 4 out of 256 (1.6%) dislocations from the dual mobility cohort compared to 7 out of 120 (5.8%), P < 0.001 from the single articulation cohort. The rates of aseptic loosening were 3.2% (8 out of 254) and 4.2% (5 out of 120), P = 0.124, respectively, between the cohorts. The re-revision rate was 5.9% for the DM liners and 8.3% in the control cohort, P = 0.38. Radiographic analyses revealed no cup migration and osteolysis in any of the patients that had no dislocations. ConclusionThe dual mobility articulations in rTHA demonstrated improved results in terms of lower dislocations rates when compared to a single articulation prostheses. Our center uses these articulations for revisions and surgeons should consider the use of these bearings when performing rTHA.

Radiographic Accuracy of Malseated Dual-Mobility Liners Varies Based on Implant Design

BackgroundDual-mobility constructs have gained popularity to mitigate dislocations after high-risk primary and revision total hip arthroplasties. Contemporary data have indicated that malseating of modular dual-mobility liners occurs in up to 6% of cases. The purpose of this cadaveric-based radiographic study was to determine the ability to accurately determine if modular dual-mobility liners were seated. MethodsThere were 10 hips (5 cadaveric pelvic specimens) used to implant modular dual-mobility liners of 2 designs. One had a liner that seated flush and the other had an extended rim. There were 20 constructs that were well-seated and 20 constructs were intentionally malseated. A comprehensive series of radiographs was reviewed by 2 blinded surgeons. Statistical analyses included Chi-squared testing, logistic regressions, and kappa statistics. ResultsRadiographic assessment of liner malseating was not accurate with an elevated rim design with misdiagnosis in 40% (16 of 40). The flush design had diagnostic errors in 5% (2 of 40; P = .0002). Logistic regressions demonstrated a significantly higher risk of misdiagnosing a malseated liner in the elevated rim group (odds ratio 13). There were 12 of 16 misdiagnoses in the elevated rim group failing to recognize a malseated liner. Each surgeon had almost perfect agreement for intraobserver reliability for flush designs (k 0.90) and fair agreement in the elevated rim design (k 0.35). ConclusionA comprehensive series of plain radiographs can reliably detect a malseated modular dual-mobility liner with a flush rim design in 95% of cases. However, elevated rim designs are more difficult to accurately identify malseating on plain radiographs.

Early clinical and radiological outcomes of the new porous titanium shell in combination with locking screw in revision total hip arthroplasty

IntroductionExtensive acetabular bone loss and poor bone quality are two key challenges often encountered in revision total hip arthroplasty. A new 3D-printed porous acetabular shell has been made available with the option to insert multiple variable-angle locking screws. We sought to evaluate the early clinical and radiological outcomes of this construct.MethodsA retrospective review of patients operated by two surgeons was performed in a single institution. Fifty-nine revision hip arthroplasties were performed in 55 patients (34 female; mean age 68.8 ± 12.3 years) for Paprosky defects I (n = 21), IIA/B (n = 22), IIC (n = 9), III (n = 7) between February 2018 and January 2022 using the novel porous titanium acetabular shell and multiple variable angle locking screws. Postoperative clinical and radiographic outcomes were locally maintained. Patient-reported outcome measures collected included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score, and the 12-item Short Form Survey.ResultsAfter a mean follow-up of 25.7 ± 13.9 months, two cases of shell migration were noted. One patient had a failed constrained mechanism and received revision to a cemented dual mobility liner. No other acetabular shells showed any evidence of radiographic loosening at the final follow-up. Preoperatively, 21 defects were classified as Paprosky grade I, 19 grade IIA, 3 grade IIB, 9 IIC, 4 grade IIIA, and 3 IIIB. The mean postoperative WOMAC function score was 84 (SD 17), WOMAC (stiffness) 83 (SD 15), WOMAC (pain) 85 (SD 15), and WOMAC (global) 85 (SD 17). The mean postoperative OHS was 83 (SD 15), and mean SF-12 physical score was 44 (SD 11).ConclusionThe additional augmentation of porous metal acetabular shells with multiple variable-angle locking screws provides reliable initial fixation with good clinical and radiological outcomes in the short term. Further studies are needed to establish the medium- and long-term outcomes.Level of evidenceIV.

Analysis of an explanted dual mobility cup after 21 years, parabolic wear pattern: A case report

A dual mobility cup was implanted in 1983 in a 43-year woman. After 31 years of normal function, we analysed the explanted materials with modern techniques. Volumetric wears of the small and large articulations of the dual-mobility construct were similar. For the first time, we demonstrated that the dual-mobility liner underwent parabolic (not linear) wear during the period of implantation.

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.

Do cobalt and chromium blood metal ion levels normalize after revision of failed metal-on-metal total hip replacements?

Increased cobalt (Co) and chromium (Cr) serum levels are one reason for revision surgery in metal on metal (MoM) total hip arthroplasty (THA) patients. Dual mobility liners are a simple revision option; however, they preserve the metal shell and stem and it is thereforenot clear if metal ion levels will fully normalize after revision surgery. Between April 2013 and December 2017 25 hips (24 patients) underwent revision from a MoM THA to an off-label dual mobility liner. Five patients were lost to follow-up and one patient refused leaving 18 patients (11 men, 7 female, average age 63.9years) for pre- and postoperative metal ion level blood tests at a minimum follow-up of 2years. Fourteen patients were revised for osteolysis, two for elevated metal ion levels and two for fluid or cysts around the femoral or acetabular component. The average preoperative Co and Cr levels were 8.3µg/l and 5.0µg/l, respectively. At a minimum follow-up of 2years (30-95months), metal ions dropped to 0.8µg/l. Harris Hip Score (HHS), Hip Osteoarthritis Outcome Score (HOOS), Visual Analog Scale (VAS) and the UCLA activity score improved non-significantly from pre- to postoperative. There was one postoperative complication in the study cohort. One patient with persisting pain required revision surgery to a standard acetabular component during the follow-up period. The off-label use of a dual-mobility liner in the current study resulted in normalization of the metal ion levels suggesting that preserving the cobalt-chromium acetabular component has little impact on ion levels. In addition, dual mobility liners have a low complication and revision rate.

Malseating of modular dual mobility liners.

AimsPrior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery.MethodsWe retrospectively reviewed the radiographs of 239 primary and revision total hip arthroplasties with a modular dual mobility liner. Two independent reviewers assessed radiographs for each patient twice for evidence of malseating, with a third observer acting as a tiebreaker. Univariate analysis was conducted to determine risk factors for malseating with Youden’s index used to identify cut-off points. Cohen’s kappa test was used to measure interobserver and intraobserver reliability.ResultsIn all, 12 liners (5.0%), including eight Stryker (6.8%) and four Zimmer Biomet (3.3%), had radiological evidence of malseating. Interobserver reliability was found to be 0.453 (95% confidence interval (CI) 0.26 to 0.64), suggesting weak inter-rater agreement, with strong agreement being greater than 0.8. We found component size of 50 mm or less to be associated with liner malseating on univariate analysis (p = 0.031). Patients with malseated liners appeared to have no associated clinical consequences, and none required revision surgery at a mean of 14 months (1.4 to 99.2) postoperatively.ConclusionThe incidence of liner malseating was 5.0%, which is similar to other reports. Component size of 50 mm or smaller was identified as a risk factor for malseating. Surgeons should be aware that malseating can occur and implant design changes or changes in instrumentation should be considered to lower the risk of malseating. Although further follow-up is needed, it remains to be seen if malseating is associated with any clinical consequences.Cite this article: Bone Jt Open 2021;2(10):858–864.

Functional Prosthetic Spacer Surgical Technique for Definitive Management of Hip Periprosthetic Joint Infection

The appropriately sized acetabular polyethylene liner is utilized. If instability is a concern, a dual mobility liner can be utilized. The back side of either chosen liner is scored with a saw or burr. In situations where significant acetabular bone loss is present, screws may be placed in the anterior and/or posterior columns to serve as rebar for the planned cement mantle. The femur is broached sequentially until an adequate fit is obtained. A cemented femoral stem is used primarily. If proximal femoral bone stock is poor, a long-cemented stem is utilized.

Preliminary results of a novel spacer technique in the management of septic revision hip arthroplasty.

Mechanical failure due to dislocation, fracture and acetabular wear is a major complication associated with the use of spacers in the management of periprosthetic joint infection (PJI). We have developed a novel custom-made spacer in the setting of two-stage septic revision hip arthroplasty and present the preliminary results of our technique. Between May 2015 and November 2017, 30 patients underwent hip revision using the ENDO spacer technique in the setting of a two-stage septic exchange arthroplasty. The technique involves the dual mobility liner and the downsized stainless cemented straight stem in combination with antibiotic-loaded PMMA bone cement. The primary outcome measure was the overall spacer complication rate, particularly spacer dislocation. Furthermore, functional outcome using the Harris Hip Score (HHS) before spacer implantation and prior re-implantation was evaluated. The mean age of the patients was 69.8years (range from 45 to 85; SD = 9.9years). No microorganisms were preoperatively found in 23 (76.7%) cases. Successful re-implantation was performed in all patients after a mean spacer duration time of 53.6days (range 14-288days; SD = 48.2). Spacer-related complications occurred in only two patients (6.7%). The HHS significantly improved from 34.0 (range 3-62; SD = 15.1) to 48.1 (range 11-73; SD = 15.7) (p = 0.0008). The ENDO spacer surgical technique is a feasible option in the treatment of periprosthetic joint infection (PJI), with a low dislocation rate. Furthermore, it allows early mobilization with the possibility of full-weight bearing.

Catastrophic failure of tripolar constrained liners due to backside wear: a novel failure mode

Constrained acetabular liners have been developed for patients who are at high risk for dislocation or who are undergoing revision surgery for recurrent dislocations. We report on 2 cases of failure of tripolar constrained liners due to severe backside polyethylene wear after dissociation of the outer polyethylene liner without dislocation, a mode of failure not previously reported. The backside of the inserts suffered severe polyethylene deformation, wear, and scratching due to dissociation from the locking mechanism. In patients with tripolar constrained liners, radiographic evidence of eccentric wear should be considered as possible occult dissociation of the polyethylene liner within the shell. Conversion to a modular dual mobility liner appears to be a viable solution in this setting.

Salvage of a monoblock metal-on-metal cup using a dual mobility liner: a two-year MRI follow-up study.

Revision of failed modular metal-on-metal total hip replacement (MoM-THA) can be technically difficult. A dual mobility liner can help to salvage a well-fixed acetabular component. The present paper reports the clinical and radiographic outcome of revision of failed Birmingham modular MoM-THA using a dual mobility liner. The present study reports on ten patients (3 female and 7 male) with 11 revision THAs. Patients underwent revision an average of 51months (range 40-73months) after index procedure. Mean follow-up after the revision was 31months (range 24-37months) and all patients underwent an MRI with metal artifact reduction software (MARS) at least twoyears after revision to assess for local polyethylene wear and osteolysis. The Harris Hip score improved from 92.2 (range 63.0-100.0) to 100.0 (p=0.072). One patient had a one-time dislocation within sevendays of surgery. No patient required additional surgeries. Radiographs showed no signs of component loosening and osteolysis and MRI imaging revealed no evidence of polyethylene wear or osteolysis. A dual mobility liner in an existing Birmingham cup can provide excellent clinical and radiological short-term results without MRI evidence of increased polyethylene wear. Post-operative hip precautions should be enforced.

Closed Reduction Conversion of a Dual Mobility Dislocation to an Intraprosthetic Dislocation

AbstractBuilding on a paucity of prior reported cases, we report on a patient with an off-label dual mobility liner, who sustained a dislocation. Following closed reduction in the emergency room, catching/grinding was felt, and imaging confirmed an intraprosthetic dislocation (IPD). This required revision hip arthroplasty. Dual mobility dislocations have the unique risk of conversion to IPDs during closed reduction attempts. There should be a low threshold to perform closed reductions in the operating room (OR) setting by an orthopaedic surgeon under full relaxation/sedation to optimize success and reduce the risk of creating an IPD.

Closed Reduction Conversion of a Dual Mobility Dislocation to an Intraprosthetic Dislocation

Building on a paucity of prior reported cases, here we present a case report on a patient with an off label dual mobility liner, who sustained a dislocation. Following closed reduction in the emergency room, catching/grinding was felt, and imaging confirmed an intraprosthetic dislocation. This required revision hip arthroplasty

The linear penetration rate is not relevant for evaluating wear of dual mobility cups: an explant study.

The linear penetration rate (LPR) has been used to estimate volumetric wear ever since metal-on-polyethylene bearings were first introduced. Annual volumetric wear and osteolysis are interrelated. The use of dual mobility cups has increased; however, the presence of two bearings needs paraclinical monitoring of wear to anticipate potential wear-related complications. Is LPR correlated to volumetric wear? Ninety-eight dual mobility liner retrievals were mapped in three-dimensions (3D) with a fully automatic stripe light scanner. Martell's method was applied to 3D maps of the explants to determine how much the centres of the inner and outer bearings had shifted in the three planes, and in particular, penetration of the femoral head in the "z" axis. The total, inner and outer wear volumes were then compared to the shift in the centres of rotation (COR) and the pre-operative X-rays. There was no relationship between wear and head penetration into the liner. There was a statistically significant relationship between the 3D centre of rotation shift and inner wear or total wear. Wear was multidirectional. LPR is ineffective for estimating wear of dual mobility inserts, since its wear not two-dimensional. In the future, a 3D imaging method with very thin slices could be used to monitor the wear of dual mobility inserts by measuring the shift in the centres of rotation, once artifacts are overcome.

The dual mobility liner: Is it ready for prime time?

Hip instability remains a pressing complication in primary and particularly revision hip arthroplasty. Dual mobility liners were introduced to combat this very issue in the mid 1970s. Initial concerns with the first generation technology concerning wear and intra-prosthetic dislocation has led to improvements in its development. Second generation technology has since been utilized and long-term studies have provided encouraging results. Dual mobility liners are very powerful, but not end all, solution to the issue of post-operative hip instability and can be a powerful tool when used.

What Are the Causes for Failures of Primary Hip Arthroplasties in France?

There are no large database cohorts describing the causes for failure of primary THAs in France. Because implants and causes for revision vary between national registers, it is important to obtain data from all countries. We therefore determined (1) the mechanisms of failure of primary THAs, (2) their order of appearance with time, (3) the types of surgical techniques and implant designs used to perform revision THAs, and (4) 90-day complications after revision THA in France. We prospectively collected data on all 2107 first-time revision THAs from 30 tertiary centers from January 1, 2010, to December 31, 2011. A dual-mobility liner had been used in 251 hips. Mean time from primary procedure to revision THA was 11.2 years (range, 1 day to 42 years). Mean age at revision was 70 years (range, 17-104 years). The causes for revision were mechanical loosening (42%), periprosthetic fracture (12%), infection (11%), wear/osteolysis (11%), dislocation (10%), surgical technique error (6%), and implant fracture (3%). The most common type of revision procedure was all-component revision (49%). A dual-mobility liner was used in 1184 hips (62%). The 90-day dislocation rate was less than 4%, and mortality rate was 1.6%. Contrary to other reported data, we found dislocation was not the main cause for failure of primary THAs but was still the more frequent early complication after revision. These findings might be related to the use of dual-mobility sockets in more than 10% of primary THAs and more than 60% of revision THAs.

Dual Poly Liner Mobility Optimizes Wear and Stability in THA: Opposes

Total hip arthroplasty (THA) is an effective intervention for the treatment of arthrosis with excellent survivorship. Nonetheless, dislocation and osteolysis remain significant complications. A dual-mobility acetabular component has been advocated to improve stability and wear. Stability is imparted by increasing the effective femoral head size, which allows a larger range of motion (ROM) before neck-socket impingement occurs. Increasing ROM, however, introduces an additional problem of bony impingement of the trochanter against the pelvis. Consequently, there is little improvement in ROM for heads >36 to 40 mm. A 0.4% incidence of instability at the larger articulation has been reported in primary THA using the dual-mobility liner, which is equivalent to reports for conventional THA. The dual-mobility liner has introduced the unique complication of intraprosthetic dislocation, where the femoral head dissociates at the smaller articulation as a result of polyethylene wear. An incidence of intraprosthetic dislocation of 3.6% has been reported, which far exceeds dislocation of conventional arthroplasty. The dual-mobility liner is a monoblock acetabular component without the capacity for augmented bony fixation. Inability to achieve primary stability has been reported as high as 18% and therefore its usefulness in revision THA is questionable. Proponents of the dual-mobility liner cite improved wear characteristics over conventional THA; however, few studies support this proposition. Retrieval studies have reported that the dual-mobility liner does not avoid wear or osteolysis. Theoretically, it is inconceivable that wear would be diminished with an additional articulation with a huge surface area, where the differential hardness has been reversed to a soft-on-hard bearing.