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Acetabular Lip Augmentation Devices for the Unstable Total Hip Replacement—A Systematic Review

Open AccessPublished:October 28, 2021DOI:https://doi.org/10.1016/j.artd.2021.09.003

      Abstract

      Background

      The optimal management strategy for instability afte total hip arthroplasty remains unclear. Acetabular lip augmentation devices may offer an operative solution for recurrent instability. This systematic review reports the clinical outcomes of acetabular lip augmentation devices in comparison to other treatment options.

      Methods

      A literature search strategy was performed of Medline, EMBASE, and CENTRAL on September 19, 2020, for all studies reporting outcomes of acetabular lip augmentation devices for recurrent dislocation after total hip arthroplasty. Non-English language articles were excluded. Clinical and survivorship data were collated and analyzed.

      Results

      Thirteen studies describing acetabular augmentation were included for analysis. A total of 644 hips in 636 patients were augmented with a mean age of 75 years (39 to 103). Five different augmentation devices were used. The posterior lip augmentation device (PLAD, DePuy) was the most used (406 hips). Overall, acetabular lip augmentation devices had a 10% postoperative dislocation rate at a mean follow-up of 49 months (0.2 to 132). The PLAD had a 3.9% subsequent dislocation rate with a mean follow-up of 51 months (0.2 to 132). Only one study compared the PLAD to a dual-mobility cup, which demonstrated shorter operative times with the PLAD but higher rates of dislocation and revision surgery.

      Conclusion

      The quality of literature on lip acetabular augmentation devices is poor. In these studies, the postoperative dislocation rate after lip acetabular augmentation was relatively high. The PLAD (DePuy) has the most evidence and may offer a therapeutic option for recurrent instability, in very specific clinical situations.

      Keywords

      Introduction

      Dislocation after primary total hip arthroplasty (THA) has a reported incidence ranging from 0.6% to 4% [
      • Masonis J.L.
      • Bourne R.B.
      Surgical approach, abductor function, and total hip arthroplasty dislocation.
      ]. Of those, 16% to 36% may sustain recurrent THA dislocation [
      • Woo R.Y.
      • Morrey B.F.
      Dislocations after total hip arthroplasty.
      ,
      • Turner R.S.
      Postoperative total hip prosthetic femoral head dislocations. Incidence, etiologic factors, and management.
      ,
      • Joshi A.
      • Lee C.M.
      • Markovic L.
      • Vlatis G.
      • Murphy J.C.
      Prognosis of dislocation after total hip arthroplasty.
      ]. Multiple factors contributing to recurrent instability, including component orientation, femoral head size, impingement, polyethylene wear, patient age, patient gender, and choice of surgical approach, have been described [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Hedlundh U.
      • Karlsson M.
      • Ringsberg K.
      • Besjakov J.
      • Fredin H.
      Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty: a matched controlled study of 65 patients using dual-energy X-ray absorptiometry and postural stability tests.
      ,
      • Jolles B.M.
      • Zangger P.
      • Leyvraz P.F.
      Factors predisposing to dislocation after primary total hip arthroplasty: a multivariate analysis.
      ].
      Numerous management strategies have been reported for recurrent THA dislocations. Previously, conservative treatment with an above-knee spica brace or hip cast-brace was considered appropriate. In 1983, Stewart reported a 73% success rate with a hip cast-brace for recurrent THA instability [
      • Stewart H.D.
      The hip cast-brace for hip prosthesis instability.
      ].
      In the majority of those with recurrent instability, however, operative intervention is required. Revision surgery may be a substantial undertaking in this patient cohort, who are often elderly and frail. Revision surgery has been associated with reported subsequent dislocation rates between 5% and 28% [
      • Berend K.R.
      • Sporer S.M.
      • Sierra R.J.
      • Glassman A.H.
      • Morris M.J.
      Achieving stability and lower-limb length in total hip arthroplasty.
      ,
      • Charissoux J.L.
      • Asloum Y.
      • Marcheix P.S.
      Surgical management of recurrent dislocation after total hip arthroplasty.
      ]. Acetabular lip augmentation devices may be used in this population.
      A lip augmentation device (Fig. 1) consists of a stainless steel backing plate and ultra-high-molecular-weight polyethylene bearing piece which are predrilled to facilitate fixation with 5 screws into the in situ polyethylene cup and contoured for a congruent articulation with the femoral head [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ]. Augmentation devices, of which the posterior lip augmentation device (PLAD; DePuy International Limited, Leeds, United Kingdom) is one, may be fixed in whichever direction the hip has a predilection to dislocate.
      Figure thumbnail gr1
      Figure 1Diagram of a lip augmentation device. A, Femoral stem implant; B, metal backing of device; C, polyethylene component of device; D, acetabular component.
      The aim of this study was to perform a systematic review of the reported clinical outcomes of the acetabular lip augmentation devices for recurrent instability after THA.

      Material and methods

      This was a systematic review of the outcomes of acetabular lip augmentation devices for recurrent instability after THA. The search strategy was designed in accordance with Cochrane guidance [
      Cochrane Effective Practice and Organisation of Care (EPOC)
      How to develop a search strategy for an intervention review.
      ].
      Medline, EMBASE, Cochrane CENTRAL, and Clinicaltrials.gov were searched on September 19, 2020, using the search strategy outlined in Table 1. Google Scholar was used to perform a cited reference search. Grey literature was assessed through www.opengrey.eu.
      Table 1The literature search strategy used for this systematic review.
      NumberSearches
      1(acetabulum∗ or acetabular or hip or hip joint).mp.
      2(posterior lip augmentation device or PLAD or lip augmentation device or lip augmentation ring).mp.
      32 or 3
      Articles that reported clinical outcomes of a lip augmentation device for unstable THA were included. Non-English language articles and studies without full-text results were excluded.
      Database results are outlined in Figure 2. Abstracts were screened by two independent reviewers. Articles were reviewed independently, and consensus met. The senior author acted as mediator for instances of reviewer discordance.
      Figure thumbnail gr2
      Figure 2The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram of the review.

      Results

      Fourteen studies [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ,
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ,
      • Güngör T.
      • Hallin G.
      Cup re-enforcement for recurrent dislocation after hip replacement.
      ,
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ,
      • Madan S.
      • Sekhar S.
      • Fiddian N.J.
      Wroblewski wedge augmentation for recurrent posterior dislocation of the Charnley total hip replacement.
      ,
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ,
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ,
      • Enocson A.G.
      • Minde J.
      • Svensson O.
      Socket wall addition device in the treatment of recurrent hip prosthesis dislocation: good outcome in 12 patients followed for 4.5 (1-9) years.
      ,
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ,
      • Bosker B.H.
      • Ettema H.B.
      • Verheyen C.C.
      • Castelein R.M.
      Acetabular augmentation ring for recurrent dislocation of total hip arthroplasty: 60% stability rate after an average follow-up of 74 months.
      ,
      • Schmidl S.
      • Jakobs O.
      • Guenther D.
      • et al.
      Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device. Archives of Orthopaedic and Trauma Surgery.
      ,
      • Hoggett L.
      • Cross C.
      • Helm T.
      Experience of the posterior lip augmentation device in a regional hip arthroplasty unit as a treatment for recurrent dislocation.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ] met the inclusion criteria for this review. Two articles [
      • Hoggett L.
      • Cross C.
      • Helm T.
      Experience of the posterior lip augmentation device in a regional hip arthroplasty unit as a treatment for recurrent dislocation.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ] presented results from the same study and were thus amalgamated for analysis. Each articles was critically appraised, as outlined in Table 2.
      Table 2Critical appraisal of included studies.
      StudyStrengthsWeaknessesBias and confoundingOverall risk of biasOverall grade of evidence
      Olerud et al. [
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ]
      First article to describe the techniqueFollow-up not specified; small numbers; no controlRetrospective; uncontrolledHighLow
      Güngör and Hallin [
      • Güngör T.
      • Hallin G.
      Cup re-enforcement for recurrent dislocation after hip replacement.
      ]
      First article with specific follow-upLacking clinical data; uncontrolled; small numbers (13)Retrospective; uncontrolledHighLow
      Bradbury et al. [
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ]
      Reasonable follow-up (3 y)Small series (16); no control; 2 different augment types usedRetrospective; uncontrolled; 2 different augment types used (different experimental interventions)HighLow
      Nicholl et al. [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ]
      Reasonable follow-up; adequate data completenessNo control; heterogenous augments; heterogenous implantsRetrospective; uncontrolled; 2 different augment types used (different experimental interventions); heterogenous implants augmentedHighLow
      Charlwood et al. [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ]
      Comparative study; complete data; detailed outcome measuresShort follow-up (2 y); low numbers (n = 20)RetrospectiveHighLow
      Madan et al. [
      • Hedlundh U.
      • Karlsson M.
      • Ringsberg K.
      • Besjakov J.
      • Fredin H.
      Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty: a matched controlled study of 65 patients using dual-energy X-ray absorptiometry and postural stability tests.
      ]
      Relatively large numbers at n = 68; homogenous groupUncontrolled; no specific follow-upRetrospective; uncontrolled; no specific follow-upHighLow
      Bottner et al. [
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ]
      Reasonable follow-upHeterogenous groups; many with multiple previous operations; previous infection in one case; dialysis patient in another—high risk; 6 had proximal femoral replacementsDifferent implants; heterogenous patient group; heterogenous treatment plansHighLow
      Gholve et al. [
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ]
      Comprehensive data; homogenousUncontrolled; short follow-up at 2 yLow numbers; uncontrolledHighLow
      Enocson et al. [
      • Enocson A.G.
      • Minde J.
      • Svensson O.
      Socket wall addition device in the treatment of recurrent hip prosthesis dislocation: good outcome in 12 patients followed for 4.5 (1-9) years.
      ]
      Long follow-up (4.5 y); homogenousUncontrolled; small numbersUncontrolled; small numbersHighLow
      McConway et al. [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ]
      Large study (n = 310); long follow-up; comprehensive data; homogenousUncontrolled; retrospectiveUncontrolled; retrospectiveHighLow
      Bosker et al. [
      • Bosker B.H.
      • Ettema H.B.
      • Verheyen C.C.
      • Castelein R.M.
      Acetabular augmentation ring for recurrent dislocation of total hip arthroplasty: 60% stability rate after an average follow-up of 74 months.
      ]
      Long follow-upSmall; uncontrolled; incomplete dataUncontrolled; retrospectiveHighLow
      Schmidl et al. [
      • Schmidl S.
      • Jakobs O.
      • Guenther D.
      • et al.
      Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device. Archives of Orthopaedic and Trauma Surgery.
      ]
      Long follow upSmall; uncontrolled; incomplete dataUncontrolled; retrospectiveHighLow
      Hoggett et al. [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]
      Comparative; long follow-up (7 y)Retrospective; sparse clinical data; historical control; different durations of follow-up (longer in the PLAD)Retrospective; different durations of follow-up; unmatched comparisonsHighLow
      Five types of acetabular lip augmentation devices were used. The PLAD (DePuy International Limited, Leeds, United Kingdom) was used in four studies and accounted for 406 of 644 cases (64%) [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ,
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ,
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]. Olerud and Karlström’s original sector method was reported in four studies [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ,
      • Güngör T.
      • Hallin G.
      Cup re-enforcement for recurrent dislocation after hip replacement.
      ,
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ]. The other described acetabular augmentation devices were the Wroblewski acetabular stabilizing wedge (DePuy) in three studies [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ,
      • Madan S.
      • Sekhar S.
      • Fiddian N.J.
      Wroblewski wedge augmentation for recurrent posterior dislocation of the Charnley total hip replacement.
      ], the antiluxation ring (Waldemar Link GmbH, Hamburg, Germany) in three studies, the Beck acetabular augmentation ring segment (Erothitan Titanimplantate AG, Schmalkalden, Germany) in one study [
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ], and the PLAD (custom-made; Waldemar Link GmbH, Hamburg, Germany) in one study [
      • Schmidl S.
      • Jakobs O.
      • Guenther D.
      • et al.
      Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device. Archives of Orthopaedic and Trauma Surgery.
      ]. Two studies assessed more than one augment type [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ].
      There were two studies with level III evidence [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ], with the remainder having level IV evidence. All studies demonstrated high risk of bias (Table 2). Funding sources were declared in 6 of 13 articles, of which 5 had no funding source and 1 article was funded by a public research institutional grant. There was no declaration of industry funding in the included studies.
      The patient demographics within each study are outlined in Table 3. A total of 644 acetabular augmentations were performed in the 13 included studies. The Charnley prosthesis was augmented in nine studies, while the four remaining studies included other arthroplasty devices (Table 3). Two studies augmented different acetabular cup types [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ], whereas one study did not specify the acetabular cup in situ [
      • Bosker B.H.
      • Ettema H.B.
      • Verheyen C.C.
      • Castelein R.M.
      Acetabular augmentation ring for recurrent dislocation of total hip arthroplasty: 60% stability rate after an average follow-up of 74 months.
      ].
      Table 3Patient demographics of studies assessing acetabular augmentation devices.
      StudyYearAugment deviceCup in situLevel of evidencePatients, nHips, nMale, nFemale, nMean age, y (range)Mean follow-up, mo (range)
      Olerud et al. [
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ]
      1985Olerud sectorCharnley4662462 (45 to 82)N/A (9 to 36)
      Güngör and Hallin [
      • Güngör T.
      • Hallin G.
      Cup re-enforcement for recurrent dislocation after hip replacement.
      ]
      1990Olerud sectorCharnley413136771 (57 to 81)12 (all 12)
      Bradbury et al. [
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ]
      1994Olerud sector in 3, Wroblewski in 13Charnley4161621473 (45 to 86)36 (12 to 70)
      Nicholl et al. [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ]
      1999Olerud sector in 18

      Wroblewski in 10
      Multiple types
      Multiple types in the study by Nicholl et al.: Stanmore, n = 6; Charnley, n = 5; Howse, n = 4; Ultralock, n = 1; Sheehan, n = 1; Kent, n = 1.
      4272852272 (50 to 99)26 (3 to 108)
      Charlwood et al. [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ]
      2002PLAD (DePuy)Charnley3202041675 (54 to 89)24 (all 24)
      Madan et al. [
      • Hedlundh U.
      • Karlsson M.
      • Ringsberg K.
      • Besjakov J.
      • Fredin H.
      Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty: a matched controlled study of 65 patients using dual-energy X-ray absorptiometry and postural stability tests.
      ]
      2002WroblewskiCharnley46868145479 (74 to 76)35 (24 to 95)
      Bottner et al. [
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ]
      2005BeckMultiple types
      Multiple types in the study by Bottner et al.: Muller Roof Ring, n = 4; LOR oval oversize revision cup, 2; Burch/Schneider cage, n = 1; Allofit press fit cup, n = 1.
      4181871165 (44 to 78)35 (24 to 52)
      Gholve et al. [
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ]
      2006PLAD (DePuy)Charnley4212181376 (62 to 88)23 (12 to 36)
      Enocson et al. [
      • Enocson A.G.
      • Minde J.
      • Svensson O.
      Socket wall addition device in the treatment of recurrent hip prosthesis dislocation: good outcome in 12 patients followed for 4.5 (1-9) years.
      ]
      2006Anti-luxation ringLubius SPII412126669 (58 to 83)54 (12 to 108)
      McConway et al. [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ]
      2007PLAD (DePuy)Charnley43073106724075 (39 to 96)48 (0.2 to 132)
      Bosker et al. [
      • Bosker B.H.
      • Ettema H.B.
      • Verheyen C.C.
      • Castelein R.M.
      Acetabular augmentation ring for recurrent dislocation of total hip arthroplasty: 60% stability rate after an average follow-up of 74 months.
      ]
      2009Antiluxation ringN/A44750123575 (58 to 94)74 (12 to 178)
      Schmidl et al. [
      • Schmidl S.
      • Jakobs O.
      • Guenther D.
      • et al.
      Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device. Archives of Orthopaedic and Trauma Surgery.
      ]
      2016PLAD (Link)EndoMark III/SP242727121582 (70 to 94)69 (30 to 103)
      Hoggett et al. [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]
      2020PLAD (DePuy)Charnley35455114377 (53 to 103)86 (45 to 128)
      OverallAll devices63664415648075 (39 to 103)49 (0.2 to 132)
      PLAD (DePuy)4024069031275 (39 to 103)51 (0.2 to 132)
      N/A, not described in the article.
      a Multiple types in the study by Nicholl et al.: Stanmore, n = 6; Charnley, n = 5; Howse, n = 4; Ultralock, n = 1; Sheehan, n = 1; Kent, n = 1.
      b Multiple types in the study by Bottner et al.: Muller Roof Ring, n = 4; LOR oval oversize revision cup, 2; Burch/Schneider cage, n = 1; Allofit press fit cup, n = 1.
      Eight of the 13 included studies reported the number of prior dislocations, while four studies reported the mean number of operations performed before acetabular augment. Of those, the average number of prior dislocations was 4.2 (range, 0 to 20). Two patients in the study by Nicholl et al. [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ] and one patient in the study by Bottner et al. [
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ] had an acetabular augment inserted during the index procedure for gross on-table instability. The mean number of previous operations was 2.5 (range, 0 to 8) (Table 4). The mean time from the index THA to insertion of the PLAD was 41 months (range, 0 to 270) (Table 4).
      Table 4The clinical outcomes of acetabular augmentation devices in included studies.
      StudyYearAugment deviceHips, nMean prior operations, n (range)Mean preoperative dislocations, n (range)Time to PLAD, mo (range)LOO, min (range)Blood loss, ml (range)Transfusion, meanLOS, d (range)Postoperative dislocation, n (%)Infection,
      Requiring reoperation.
      n (%)
      Repeat PLAD, n (%)Screw breakage, n (%)Aseptic loosening
      Requiring reoperation.
      , n (%)
      Subsequent revision, n (%)
      Olerud et al. [
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ]
      1985Olerud sector63.7 (1 to 8)N/AN/AN/AN/AN/A10 (3 to 18)0 (0)0 (0)0 (0)0 (0)0 (0)0 (0)
      Güngör and Hallin [
      • Güngör T.
      • Hallin G.
      Cup re-enforcement for recurrent dislocation after hip replacement.
      ]
      1990Olerud sector13N/AN/AN/AN/AN/AN/AN/A1 (7.7)0 (0)0 (0)6 (46)N/A0 (0)
      Bradbury et al. [
      • Bradbury N.
      • Milligan G.F.
      Acetabular augmentation for dislocation of the prosthetic hip. A 3 (1-6)-year follow-up of 16 patients.
      ]
      1994Olerud sector in 3, Wroblewski in 13162.7 (1 to 3)N/AN/AN/AN/AN/AN/A3 (19)0 (0)1 (6.3)0 (0)0 (0)2 (13)
      Nicholl et al. [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ]
      1999Olerud sector in 18

      Wroblewski in 10
      281.8 (1 to 5)2.25 (0 to 8)29 (0 to 240)N/AN/AN/AN/A5 (18)0 (0)0 (0)1 (3.6)1 (3.6)5 (18)
      Charlwood et al. [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ]
      2002PLAD (DePuy)20N/A3 (2 to 6)N/A59 (45 to 80)300 (150 to 600)0.77 (5 to 8)0 (0)0 (0)0 (0)0 (0)0 (0)0 (0)
      Madan et al. [
      • Hedlundh U.
      • Karlsson M.
      • Ringsberg K.
      • Besjakov J.
      • Fredin H.
      Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty: a matched controlled study of 65 patients using dual-energy X-ray absorptiometry and postural stability tests.
      ]
      2002Wroblewski68N/A4 (1 to 12)N/AN/AN/AN/AN/A16 (24)3 (4.4)7 (10)3 (4.4)0 (0)1 (1.5)
      Bottner et al. [
      • Bottner F.
      • Steinbeck J.
      • Winkelmann W.
      • Gotze C.
      Acetabular augmentation ring for recurrent dislocations in revision arthroplasty.
      ]
      2005Beck182.9 (2 to 5)4.9 (0 to 20)8.4 (0 to 60)N/AN/AN/AN/A6 (33)3 (17)0 (0)0 (0)4 (22)10 (56)
      Gholve et al. [
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ]
      2006PLAD (DePuy)21N/AN/A72 (12 to 144)N/A130 (80 to 280)04 (3 to 8)2 (9.5)0 (0)2 (9.5)0 (0)0 (0)0 (0)
      Enocson et al. [
      • Enocson A.G.
      • Minde J.
      • Svensson O.
      Socket wall addition device in the treatment of recurrent hip prosthesis dislocation: good outcome in 12 patients followed for 4.5 (1-9) years.
      ]
      2006Antiluxation ring12N/A2.7 (1 to 7)24 (0 to 48)N/AN/AN/AN/A1 (8.3)0 (0)0 (0)0 (0)0 (0)0 (0)
      McConway et al. [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ]
      2007PLAD (DePuy)310N/A5 (1 to 6)46 (0 to 270)N/AN/AN/A12 (2 to 124)5 (1.6)4 (1.3)0 (0)31 (10)1 (0.3)4 (1.3)
      Bosker et al. [
      • Bosker B.H.
      • Ettema H.B.
      • Verheyen C.C.
      • Castelein R.M.
      Acetabular augmentation ring for recurrent dislocation of total hip arthroplasty: 60% stability rate after an average follow-up of 74 months.
      ]
      2009Antiluxation ring50N/A2.5 (2 to 5)N/AN/AN/AN/AN/A15 (30)5 (10)7 (14)15 (30)0 (0)9 (18)
      Schmidl et al. [
      • Schmidl S.
      • Jakobs O.
      • Guenther D.
      • et al.
      Effective prevention of recurrent dislocation following primary cemented Endo-MarkIII/SP2 total hip arthroplasty using a posterior lip augmentation device. Archives of Orthopaedic and Trauma Surgery.
      ]
      2016PLAD (Link)27N/A2.6 (2 to 4)10 (IQR: 13)41 (25 to 60)N/AN/AN/A2 (7.4)0 (0)0 (0)1 (3.7)0 (0)2 (7.4)
      Hoggett et al. [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]
      2020PLAD (DePuy)55N/AN/AN/A43 (21 to 84)N/AN/A15 (3 to 99)9 (16)3 (5.5)0 (0)1 (1.8)1 (1.8)2 (3.6)
      OverallAll devices6442.5 (1 to 8)4.2 (0 to 20)42 (0 to 270)46 (21 to 84)213 (80 to 600)0.34 (0 to 0.7)8 (2 to 124)65 (10)18 (2.8)17 (2.6)58 (9)7 (1.1)35 (5.4)
      PLAD (DePuy)406N/A4.9 (1 to 6)48 (12 to 270)47 (21 to 84)213 (80 to 600)0.34 (0 to 0.7)8 (2 to 124)16 (3.9)7 (1.7)2 (0.49)32 (7.9)2 (0.49)6 (1.5)
      IQR, interquartile range; LOO, length of operation; LOS, length of stay; N/A, not available within the text of the article.
      a Requiring reoperation.
      The mean follow-up for all augment types was 49 months (range, 0.2 to 132) (Table 3). Specifically, the mean follow-up for the PLAD (DePuy) was 51 months (range, 0.2 to 132). The clinical outcomes from acetabular lip augmentation are described in Table 4.
      The overall postoperative dislocation rate after acetabular lip augmentation was 10% (65 of 644). Postoperative dislocation rate varied by augment type (Table 5). The Beck acetabular augmentation ring had the highest dislocation rate at 33% (1 study, 6 of 18 hips). Comparatively, the PLAD from DePuy had the lowest pooled postoperative dislocation rate at 3.9% (4 studies, 16 of 406 hips). Notably, one study reported the dislocation rate as high as 16% (9 of 55 hips) [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ].
      Table 5Postoperative dislocation rate after acetabular lip augmentation.
      AugmentHipsDislocations (%)
      Beck186 (33)
      Waldemar6216 (26)
      Wroblewski6816 (24)
      Mixed
      Mixed: Olerud sector in 21, Wroblewski in 23. No differentiation in dislocation rate by individual device in the original papers.
      448 (18)
      PLAD (LINK)272 (7.4)
      Olerud sector191 (5.3)
      PLAD (DePuy)40616 (3.9)
      Total64465 (10)
      a Mixed: Olerud sector in 21, Wroblewski in 23. No differentiation in dislocation rate by individual device in the original papers.
      Duration of operation was recorded in three studies, with a mean of 46 minutes (range, 21 to 84), while blood loss was recorded in two studies, with a mean of 213 millilitres (range, 80 to 600).
      Five studies reported length of stay, with an overall mean of 11.7 days (range, 3 to 124). There were 18 reported cases (2.8%) of deep-wound infection, which was defined as requiring reoperation. Repeat acetabular lip augmentation was performed in 17 cases (2.6%). There were 8 reported cases (1.3%) of aseptic loosening across 12 studies. Screw breakage occurred in 58 cases (9%). Thirty-five patients (5.4%) across 13 studies ultimately progressed to full revision of the THA (Table 5).
      The PLAD (DePuy) accounted for most of the acetabular lip augmentation devices assessed (406 of 644, 63%). This device demonstrated lower rates of postoperative dislocation (16 patients, 3.6%) and THA revision (6 patients, 1.5%) than other devices (Table 4, Table 5). Two patients (0.49%) in the PLAD (DePuy) subgroup developed aseptic loosening requiring revision (1 femoral stem, 1 acetabular component).
      Two patients in the study by Gholve et al. [
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ] sustained dislocation after PLAD (DePuy) insertion which was attributed to suboptimal device positioning [
      • Gholve P.A.
      • Lovell M.E.
      • Naqui S.Z.
      Minimal surgical approach for recurrent hip dislocation using the posterior lip augmentation device for the Charnley hip arthroplasty.
      ]. In both cases, resiting the device more anteriorly prevented further dislocation. Five patients in the study by McConway et al. sustained a postoperative dislocation [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ], although the authors did not describe the proposed modes of failure. One of the five had broken screws. However, 30 patients in the same study developed broken screws without failure [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ], implying this was not the causative element.

      Discussion

      The pooled postoperative dislocation rate of all acetabular lip augmentation devices was 10% in the thirteen included studies. The PLAD (DePuy), accounting for 64% of cases, had a lower pooled postoperative dislocation rate of 3.9%. Furthermore, the PLAD (DePuy) demonstrated a low complication rate and a low rate of progression to full revision (1.5%).
      The Charnley low-friction arthroplasty, first implanted in 1962, [
      • Charnley J.
      Total hip replacement by low-friction arthroplasty.
      ] was the first widespread total hip replacement. To reduce particulate wear, small head sizes of 22.225 mm were used [
      • Charnley J.
      Total hip replacement by low-friction arthroplasty.
      ]. However, this predisposed the Charnley THA to recurrent instability [
      • Berry D.J.
      • von Knoch M.
      • Schleck C.D.
      • Harmsen W.S.
      The cumulative long-term risk of dislocation after primary Charnley total hip arthroplasty.
      ].
      The postoperative dislocation rate of a hip prosthesis is cumulative over its lifespan [
      • Berry D.J.
      • von Knoch M.
      • Schleck C.D.
      • Harmsen W.S.
      The cumulative long-term risk of dislocation after primary Charnley total hip arthroplasty.
      ]. With survival of nearly 44% at 35 years [
      • Warth L.C.
      • Callaghan J.J.
      • Liu S.S.
      • Klaassen A.L.
      • Goetz D.D.
      • Johnston R.C.
      Thirty-five-year results after Charnley total hip arthroplasty in patients less than fifty years old. A concise follow-up of previous reports.
      ], options for operative management of instability remains important. These options include acetabular augmentation devices or formal revision surgery, including dual-mobility cups.
      Olerud and Karlström first described acetabular augmentation in 1985, augmenting the existing acetabular component with a polyethylene wedge cut from another acetabular component [
      • Olerud S.
      • Karlström G.
      Recurrent dislocation after total hip replacement. Treatment by fixing an additional sector to the acetabular component.
      ]. Subsequently, the PLAD (DePuy International Limited, Leeds, United Kingdom) was developed to constrain the femoral head within the acetabular component [
      • Nicholl J.E.
      • Koka S.R.
      • Bintcliffe I.W.
      • Addison A.K.
      Acetabular augmentation for the treatment of unstable total hip arthroplasties.
      ,
      • Hedlundh U.
      • Karlsson M.
      • Ringsberg K.
      • Besjakov J.
      • Fredin H.
      Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty: a matched controlled study of 65 patients using dual-energy X-ray absorptiometry and postural stability tests.
      ]. These devices differ from constrained acetabular implants as they are attached to the in situ acetabular component and resist femoral head subluxation in a specific direction (Fig. 1).
      McConway et al reported the largest series of acetabular lip augmentation devices [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ]. They described 310 cases of PLAD (DePuy) insertion for THA instability. Their series accounts for 76% of PLAD (DePuy) cases and 48% of all lip augmentation cases described in the literature [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ]. They reported only 5 postoperative dislocations (1.6%) at a mean follow-up of 48 months.
      Dual-mobility acetabular cups offer an increasingly popular solution to the unstable THA [
      • Blakeney W.G.
      • Epinette J.A.
      • Vendittoli P.A.
      Dual mobility total hip arthroplasty: should everyone get one.
      ]. First devised by Bousqet in 1977 to address the problem of postoperative instability with small head sizes [
      • Noyer D.
      • Caton J.H.
      Once upon a time. Dual mobility: history.
      ], the cups incorporate two advantageous elements: a small head to reduce polyethylene wear, and a large, mobile, polyethylene intermediary cup within a metal-backed cup to increase jump distance and thus reduce dislocation [
      • Neri T.
      • Philippot R.
      • Klasan A.
      • et al.
      Dual mobility acetabular cups for total hip arthroplasty: advantages and drawbacks.
      ]. A recent systematic review found a 2.2% postoperative dislocation rate after revision THA at mean 4.1 years of follow-up [
      • Reina N.
      • Pareek A.
      • Krych A.J.
      • Pagnano M.W.
      • Berry D.J.
      • Abdel M.P.
      Dual-mobility constructs in primary and revision total hip arthroplasty: a systematic review of comparative studies.
      ]. The perceived disadvantages of revision to a dual-mobility cup are increased surgical invasiveness, duration of operation, and blood loss [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ].
      Two studies [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ,
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ] compared the PLAD (DePuy) to formal THA revision for postoperative dislocation. Charlwood et al retrospectively compared 20 patients who underwent PLAD to 20 who underwent revision THA [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ]. They found no cases of dislocation in either group and similar Oxford Hip Scores at 2 years of follow-up. However, the PLAD demonstrated shorter operative durations (59 vs 171 min), less blood loss (300 vs 1800 ml), shorter length of stay (7 vs 11 days), and lower rates of wound complications (0 of 20 vs 2 of 20). The authors concluded the PLAD was a valid alternative for this patient cohort [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ].
      In the second comparative study, Hoggett et al. compared a historic cohort of 54 patients who received a PLAD (DePuy) to 28 patients who underwent acetabular revision with a dual-mobility cup for recurrent dislocation after THA [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]. Operative duration was shorter for the PLAD group (43 vs 71 min). The mean length of stay was similar for both groups (15 vs 15 days), but the PLAD had higher rates of deep wound infection (5% vs 0%).
      Hoggett et al. found a higher postoperative dislocation rate (16% vs 0%) and revision rate (25% vs 0%) in the PLAD (DePuy) group (mean follow-up, 86 months) than those in revision with a dual-mobility cup with a shorter follow-up period (mean follow-up, 55 months). However, this study used asynchronous, uncontrolled groups without randomization and with high risk of confounder bias. In addition, this relatively small study accounted for 9 of 16 total PLAD (DePuy) failures reported in the literature.
      Of the 406 hips augmented with the PLAD (DePuy), 16 (3.9%) sustained a postoperative dislocation. Acetabular lip augmentation may offer a less morbid undertaking in this typically-frail cohort, which yields a stable hip joint in 96%. For those who continue to dislocate after a PLAD, a more significant revision procedure still remains an option.
      Lip augmentation devices may only be used where the acetabular component is stable. Their use is contraindicated if component loosening, excess polyethylene wear, or gross malpositioning are present [
      • McConway J.
      • O’Brien S.
      • Doran E.
      • Archbold P.
      • Beverland D.
      The use of a posterior lip augmentation device for a revision of recurrent dislocation after primary cemented Charnley/Charnley Elite total hip replacement: results at a mean follow-up of six years and nine months.
      ].
      This review is significantly limited by the quality of studies in the published literature. All but two studies were noncomparative case series. Of the two comparative cohort studies, one comparison used an unmatched historical cohort. One cohort study supported the PLAD (DePuy), [
      • Charlwood A.P.
      • Thompson N.W.
      • Thompson N.S.
      • Beverland D.E.
      • Nixon J.R.
      Recurrent hip arthroplasty dislocation: good outcome after cup augmentation in 20 patients followed for 2 years.
      ] while the other did not [
      • Hoggett L.
      • Cross C.
      • Helm A.
      Acetabular revision using a dual mobility cup as treatment for dislocation in Charnley total hip arthroplasty.
      ]. All studies in this review had a high risk of bias leading to low quality of evidence. The risk of bias was predominantly driven by the lack of controls and by selection bias on using asynchronous, unmatched controls [
      • Sterne J.A.
      • Hernán M.A.
      • Reeves B.C.
      • et al.
      ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions.
      ]. Randomized, comparative studies with long follow-up are required to determine the optimal management strategy for recurrent THA instability.
      Instability after THA has several contributary factors, most of which are not addressed by a lip augmentation device. With the availability of modular revision implants and dual-mobility cups, lip augmentation devices have been superceded as the operative treatment of instability. Most THA instability cases will be treated with formal THA revision with or without a dual-mobility cup. However, some studies report positive results with lip augmentation devices, particularly with the PLAD (DePuy) implant. Thus, some patient populations, in very specific situations, may be treated with a lip augmentation device.

      Conclusions

      This systematic review describes outcomes of acetabular lip augmentation for recurrent instability after THA. The assessed studies were of low quality with high risk of bias. Of acetabular augmentation devices, the PLAD (DePuy) has the most evidence. Although the majority will require formal THA revision, lip augmentation devices may offer a therapeutic option in very specific circumstances.

      Funding

      This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

      Conflicts of interest

      The authors declare there are no conflicts of interest.

      Supplementary data

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