Pelvic Discontinuity Research Articles

Custom triflange revision acetabular components for significant bone defects and pelvic discontinuity: Early UK experience

AimsWe report our early experience in acetabular reconstruction for significant bone loss and pelvic discontinuity using custom triflange acetabular components. Patients and methodsRetrospective consecutive review of all patients treated at our specialist tertiary unit with significant acetabular defects (Paprosky 3A/3B) and pelvic discontinuity who were reconstructed with custom triflange implants. The primary outcomes were radiographic failure and complications. Results17 patients (17 hips) were included; 3 males/14 females with a mean age of 72 years (range 61–83). The average follow-up was 3.6 years (2–7 years). Bony defects were Paprosky 3B in 13/17 hips (76%) with pelvic discontinuity encountered in the majority of cases 15/17 hips (88%) and intra-pelvic failed components in 11/17 (64%). At final follow up, no radiographic failures were observed although three patients developed complications (17.6%); haematoma requiring washout out; intra-operative ilium fracture; and recurrent dislocation in one patient. ConclusionsOur experience suggest that acceptable outcomes can be achieved with custom implants for this group of challenging patients, although longer follow up is needed to monitor future implants’ failure.

Acetabular custom-made implants for severe acetabular bone defect in revision total hip arthroplasty: a systematic review of the literature.

The management of acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). The aim of this systematic review is to summarize and critically analyze indications, complications, clinical and radiological outcomes of custom-made acetabular components in rTHA. A systematic review of English literature was performed on Medline. Retrospective or prospective studies with minimum 2years of follow-up (FU) were included. The PRISMA 2009 flowchart and checklist were considered to edit the review. Rates of intra- or post-operative complications, aseptic loosening (AL), periprosthetic joint infection (PJI), reoperations and re-revisions rates were extrapolated. 18 articles with a level of evidence of IV were included. Six hundred and thirty-four acetabular custom components (627 patients) with a mean FU of 58.6 ± 29.8months were analyzed. The studies showed good clinical and functional outcomes. Custom-made acetabular components allowed a stable fixation with 94.0 ± 5.0% survival rate. The estimated rate of re-operations and re-revisions were 19.3 ± 17.3% and 5.2 ± 4.7%, respectively. The incidence of PJI was 4.0 ± 3.9%. The acetabular custom-made implants represent a reliable solution for pelvic discontinuity and particular cases of bone loss classified as Paprosky Type IIIA-B or type III-IV according to American Academy of Orthopaedic Surgeons system where the feature of the defect cannot be handled with standard implants. This strategy allows to fit the implant to the residual host bone, bypassing the bony deficiency and restoring hip biomechanics. Satisfactory clinical and radiological outcomes at mid-term follow-up are reported in literature.

Reconstruction for pelvic discontinuity and massive acetabular defects

ObjectiveThe acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive series of cases. Material and methodsRetrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary arthroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect mechanical failures and loosening of the implant. ResultsWith a middle follow-up of 45.06 months (12–73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13.63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d’Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16–55) to 72 (40–90) in the latest follow up. ConclusionThe acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.

Mid-term results after revision total hip arthroplasty with custom-made acetabular implants in patients with Paprosky III acetabular bone loss.

Severe acetabular bone loss, both with or without pelvic discontinuity, remains a challenge in revision total hip arthroplasty (RTHA). The goal of our study was to evaluate the mid-term results for consecutive patients with Paprosky III acetabular bone loss with or without pelvic discontinuity who needed RTHA with custom-made acetabular implants and to compare the results to those of other studies. Sixty-eight (68) patients with severe acetabular bone loss (Paprosky Type IIIa and IIIb), who required RTHA, were included in our study. All prostheses were constructed on the basis of thin-layer computed tomography (CT) scans of the pelvis. The visual analogue scale (VAS), Harrison hip score (HHS), and clinical and radiographic follow-up assessments were used to evaluate the outcome. The average follow-up time was 43months (range 1-120months). Implant survival at last follow-up was 75% (51 of 68). Kaplan-Meier survival analysis, with explantation as the endpoint, revealed survival rates of 82.7% (3years) and 77% (5years). Patients with revision of the acetabular component only had a significant higher survival rate (p 0.012). Overall revision rate was 36.7%. Reinfection rate was 34.4%. Complications included 15 (22%) periprosthetic joint infections (PJI), 7 dislocations (10.2%), and 2 aseptic loosenings (2.9%). Mean VAS at last follow-up was 1.45 compared to 3.2 preoperatively, while mean HHS improved from 21.1 points preoperatively to 61 at last follow-up. The change in both scores was thus significant (p < 0.001). Defect reconstruction with custom-made modular acetabular implants can be a good, nevertheless expensive, treatment option with clinically and radiologically satisfying results in comparison to recent studies in the literature. Nevertheless, high postoperative complication rates, especially in terms of PJI, remain a challenge.

Acetabular revision arthroplasty with anovel cementless augment-and-modular-cage system (MRS-C) : Surgical technique and preliminary clinical results

Optimal reconstruction of acetabular anatomy and primarily stable bridging even of large bone defects in hip revision surgery by intraoperative cementless application of highly modular components of the MRS-TITAN Comfort (MRS-C) system according to the augment-and-modular-cage principle. Acetabular defect situations in hip revision surgery, hereditary/acquired acetabular deformities, severe secondary hip osteoarthritis. Extended periacetabular defects of the dorsal pillar, pelvic discontinuities, persisting posttraumatic or periprosthetic infections, lack of intraoperative bony anchorage options. Conventional positioning. Flexible selection of approach (posterolateral, anterolateral or transgluteal) to the hip joint, if possible using aprevious approach. Implant removal, preparation and intraoperative acetabular defect evaluation. Optional impaction bone grafting for biological downsizing. Selection of modular components and augments depending on the defect. Preparation of the obturator foramen for anchorage of the caudal flange. Optional preparation of the os ilium for additional fixation of the cage with flanges. Fixation with polyaxial screws and selection of version/inclination of the cup component. Selection of the inlay (polyethylene/ceramic). Partial weight-bearing with 20 kg body-weight for 6weeks with crutches. Prophylaxis for deep vein thrombosis and heterotopic ossification. Additional adapted antibiotic therapy in cases of infection. Aminimum 1‑year follow-up of 42patients showed significant improvements of Harris Hip Scores (p < 0.0001), adequate reconstruction of the physiologic center of rotation (x-ray controlled in the vertical plane, referenced to the contralateral side), and aclear reduction of preoperative leg length discrepancies. No significant changes in range of motion. No implant-associated complications noted. Based on the short follow-up results, the implant proves as suitable for reconstruction of even large acetabular bone defects.

The mid-long term results of reconstructional cage and morselized allografts combined application for the Paprosky type III acetabular bone defects in revision hip arthroplasty

BackgroundSevere acetabular bone defects is a complex problem in revision hip arthroplasty, cage is one of the reconstruction options. The purpose of this study is to report the mid-long term clinical and radiographic results of Paprosky type III acetabular bone defects revised with reconstructional cage and morselized allogeneic cancellous bone graft without impaction.MethodsWe retrospectively analyzed 28 patients who underwent revision hip arthroplasty with reconstructional cage and allogeneic cancellous bone graft between January 2007 and January 2016. There were 13 Paprosky type IIIA bone defect patients and 15 Paprosky type IIIB bone defect patients and 4 patients of the 15 were also with pelvic discontinuity. Clinical assessment included Harris Hip Score (HHS) and Short Form-12 (SF-12). Radiographic assessment included center of rotation, cage migration, and bone graft incorporation.ResultsAll patients were followed up with a mean follow-up of 79.5 months (range 38–141), HHS improved from 31.4 (13–43) points preoperatively to 84.6 (55–94) points at last follow-up and SF-12 also improved significantly. There was 1 re-revision for the cage loosening and screw breakage at 61 months after surgery, and 2 patients had nonprogressive radiolucency in zone III and the junction of zone II and zone III at the bone implant interface.ConclusionThe reconstructional cage combining with morselized allografts without impaction achieves a good result with a high complete allograft incorporation rate in Paprosky type III acetabular bone defects.

Outcomes of Acetabular Reconstructions for the Management of Chronic Pelvic Discontinuity: A Systematic Review

BackgroundA number of articles have been published reporting on the clinical outcomes of various acetabular reconstructions for the management of chronic pelvic discontinuity (PD). However, no systematic review of the literature has been published to date comparing the outcome and complications of different approaches to reconstruction. MethodsThe US National Library of Medicine (PubMed/MEDLINE) and EMBASE were queried for publications from January 1980 to January 2019 using keywords pertinent to total hip arthroplasty, PD, acetabular dissociation, clinical or functional outcomes, and revision total hip arthroplasty or postoperative complications. ResultsOverall, 18 articles were included in this analysis (569 cases with chronic PD). The overall survival rate of the acetabular components used for the treatment of chronic PD was 84.7% (482 of 569 cases) at mid-term follow-up, whereas the most common reasons for revision were aseptic loosening (54 of 569 hips; 9.5%), dislocations (45 of 569 hips; 7.9%), periprosthetic joint infection (30 of 569 hips; 5.3%), and periprosthetic fractures (11 of 569 hips; 1.9%). Both pelvic distraction technique (combined with highly porous shells) and custom triflanges resulted in less than 5% failure rates (96.2% and 95.8%, respectively) at final follow-up. Also, highly effective in the treatment of PD were cup-cages and highly porous shells with and/or without augments with 92% survivorship free of revision for aseptic loosening for both reconstruction methods. Inferior outcomes were reported for conventional cementless shells combined with acetabular plates (72.7%) as well as ilioischial cages and reconstruction rings (66.7% and 60.6% survivorship, respectively). ConclusionThe current literature contains moderate quality evidence in support of the use of custom triflange implants and pelvic distraction techniques for the treatment of chronic PD, with a less than 5% all-cause revision rate and low complication rates at mean mid-term follow-up. Cup-cages and highly porous shells with or without augments could also be considered for the treatment of PD because both resulted in greater than 90% survival rates. Finally, there is still no consensus regarding the impact of different types of acetabular reconstruction methods on optimizing the healing potential of PD, and further studies are required in this area to better understand the influence of PD healing on construct survivorship and functional outcomes with each reconstruction method.

Triflange acetabular reconstruction for pelvic discontinuity through a direct anterior approach

A 74-year-old female patient presented to our clinic with pelvic discontinuity after multiple revision total hip surgeries requiring custom triflange acetabular reconstruction, which we accomplished through a direct anterior approach to the hip. The direct anterior approach to the hip has grown in popularity but still has the reputation of being a minimally invasive approach without the capacity for extensile exposure in the revision setting. We describe the extensile technique and demonstrate through our case the ability to perform the most challenging cases through this approach and discuss the potential benefits of its utilization.

Reconstrucción acetabular con el sistema Cup-Cage para discontinuidades pélvicas y defectos acetabulares masivos

ObjectiveThe acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive serie of cases. Material and methodsRetrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary artroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect machanical failures and loosening of the implant. ResultsWith a middle follow-up of 45.06 months (12-73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13,63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d’Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16-55) to 72 (40-90) in the latest follow up. ConclusionThe acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.

Surgical Treatment of Pelvic Discontinuity: A Systematic Review and Meta-Analysis.

Pelvic discontinuity is a rare condition that is treated with a range of implant constructs. However, surgical failure rates are high, and outcome data are inconsistent. It is therefore difficult to gain a clear picture of whether recently developed constructs (antiprotrusio cage [APC], cup-cage, custom triflange, and porous metal) provide better outcomes in terms of mechanical failure and complications in the short to long terms. This study investigated the failure and complication rates associated with cage constructs and porous metal technologies. A systematic review and meta-analysis were performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines to evaluate the studies showing pelvic discontinuity in revision total hip arthroplasty. Data retrieved included the intervention performed, length of follow-up, mechanical failure, and other complication rates (dislocation, infection, neurological, loosening, migration). Study quality was assessed with the Methodological Index for Non-Randomized Studies (MINORS) instrument. Pooled mechanical failure and complication rates were calculated using MetaXL 5.3. None of the included 30 articles (n = 585 hips) were of high quality. The meta-analyses revealed a mechanical failure rate of 14% for all constructs combined. Custom triflange (5%) and cup-cage (7%) had the lowest mechanical failure rates compared with the commonly used APC (25%) and porous metal (12%). The overall other complication rate was 28%, with cup-cage lower at 21% compared with APC (34%) and custom triflange (28%). Long-term evidence investigating both interventions and porous metal technology is limited. Mechanical failure rates for cup-cage and custom triflange were lowest. The other complication rate for cup-cage was lower than the pooled average. The study quality was limited, indicating a need for better studies and/or a registry. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Cup-Cage Construct Using Porous Cup with Burch-Schneider Cage in the Management of Complex Acetabular Fractures.

PurposeCup-cage construct technique was developed to address the massive acetabular defects during revision hip arthroplasty. Indications have extended to complex acetabular fractures with pelvic discontinuity necessitating acute total hip arthroplasty. However, its use is constrained in low socioeconomic countries due to non-availability of the original cages from Trabecular Metal Acetabular Revision System and high cost. We used a novel technique using the less expensive Burch-Schneider (BS) cage and Trabecular Metal Revision Shell (TMRS) to address the problem.Materials and MethodsWe reviewed a consecutive series of 8 cases of acetabular fractures reconstructed using a ‘cup-cage construct’ technique using a BS cage along with a TMRS. The mean age of the patients was 61.4 years. Patients were followed up for a mean period of 50.5 months (24 to 72 months). The patients were assessed clinically with Harris Hip Score and radiologically with serial X-rays.ResultsAll the patients were available at the latest follow up. The mean Harris Hip Score was 87.2. There was no radiological evidence of failure. One patient had dislocation two months following the surgery, which was treated by closed reduction and hip abduction brace. One patient developed an infection at 3 weeks necessitating debridement. The same patient had sciatic nerve palsy that recovered after 4 months.ConclusionThis novel technique of the cup-cage construct seems to provide a stable construct at short to midterm follow-up. However, a long-term follow up would be required.

Mid-Term Outcomes of Revision Hip Arthroplasty with Acetabular Augments

Acetabular defects are a major obstacle to achieving good outcomes after revision hip arthroplasty. One way to deal with this problem is to use acetabular augments. We aimed to describe mid-term outcomes of revision hip arthroplasty using acetabular augments.Materials and methods. We analyzed 85 cases (83 patients) of revision hip arthroplasty using acetabular augments performed during 2012-2018 period: 53 women and 30 men with average age of 57±13 years (25-79). Distribution of acetabular defects was: 51 cases — Paprosky IIIA, 17 cases — Paprosky IIIB, 12 cases — Paprosky IIB, 5 cases — Paprosky IIC. 14 patients had chronic pelvic discontinuity. Aseptic loosening was indication for the operation in 83 cases, periprosthetic hip fracture — 1, dislocation — 1. The amount of previously undregone ipsilateral hipsurgeries was 1 in 35 cases, 2 in 25 cases, 3 and more in 25 cases. Average follow-up period was 38±19 months (1-79).Results. The average HHS score improved from 37±7 preoperatively to 73±9 after 3 months and to 80±11 after 12 months postoperatively (p = 0.001). Average VAS score improved from 7±2 preoperatively to 4±1 after 3 months and to 3±1 after 12 months postoperatively (p = 0.001). Stable acetabular fixation was achieved in each case according to X-ray findings at final follow-up. However, radiolucent lines were present around the cup in 10 cases (11.8 %) followed by no clinical evidence of aseptic loosening. Hip center of rotation was restored from 26.40±18.38 mm (4-75) preoperatively to 4.78±5.02 mm (0-20) postoperatively relatively to 0 point. Complications manifested in 9 out of 85 cases (10,6%). Distribution of complications was: periprosthetic joint infection in 6 cases, recurrent dislocation — 2, periprosthetic hip fracture — 1.7 patients required implant removal and exchange.Conclusions. Good mid-term outcomes can be achieved using acetabular augments during hip revision surgery in setting of acetabular defects. Acetabular augments are a reliable option in case of Paprosky IIIB, IIIA defects and chronic pelvic discontinuity, providing good mechanical stability.

Mid-Term Outcomes of Revision Hip Arthroplasty with Acetabular Augments

Acetabular defects are a major obstacle to achieving good outcomes after revision hip arthroplasty. One way to deal with this problem is to use acetabular augments. We aimed to describe mid-term outcomes of revision hip arthroplasty using acetabular augments.Materials and methods. We analyzed 85 cases (83 patients) of revision hip arthroplasty using acetabular augments performed during 2012-2018 period: 53 women and 30 men with average age of 57±13 years (25-79). Distribution of acetabular defects was: 51 cases — Paprosky IIIA, 17 cases — Paprosky IIIB, 12 cases — Paprosky IIB, 5 cases — Paprosky IIC. 14 patients had chronic pelvic discontinuity. Aseptic loosening was indication for the operation in 83 cases, periprosthetic hip fracture — 1, dislocation — 1. The amount of previously undregone ipsilateral hipsurgeries was 1 in 35 cases, 2 in 25 cases, 3 and more in 25 cases. Average follow-up period was 38±19 months (1-79).Results. The average HHS score improved from 37±7 preoperatively to 73±9 after 3 months and to 80±11 after 12 months postoperatively (p = 0.001). Average VAS score improved from 7±2 preoperatively to 4±1 after 3 months and to 3±1 after 12 months postoperatively (p = 0.001). Stable acetabular fixation was achieved in each case according to X-ray findings at final follow-up. However, radiolucent lines were present around the cup in 10 cases (11.8 %) followed by no clinical evidence of aseptic loosening. Hip center of rotation was restored from 26.40±18.38 mm (4-75) preoperatively to 4.78±5.02 mm (0-20) postoperatively relatively to 0 point. Complications manifested in 9 out of 85 cases (10,6%). Distribution of complications was: periprosthetic joint infection in 6 cases, recurrent dislocation — 2, periprosthetic hip fracture — 1.7 patients required implant removal and exchange.Conclusions. Good mid-term outcomes can be achieved using acetabular augments during hip revision surgery in setting of acetabular defects. Acetabular augments are a reliable option in case of Paprosky IIIB, IIIA defects and chronic pelvic discontinuity, providing good mechanical stability.

Reconstruction of massive acetabular bone loss with pelvic discontinuity

Reconstruction of massive acetabular bone loss with pelvic discontinuity

Cup-cage construct for massive acetabular defect in revision hip arthroplasty- A case series with medium to long-term follow-up

ObjectiveCup-cage reconstruction has emerged as a possible solution for managing massive acetabular defects with a few existing studies reporting encouraging results at mid-term follow-up. We present our experience with this unitised construct. MethodSix patients (7 hips) with a mean age of 76 years (73–81) were revised due to catastrophic aseptic failure of a primary cup implanted 10–19 years previously, having a Paprosky type 3B acetabular defect. ResultsAt a mean follow-up of 72 months (63–140) no cases have required re-revision. Oxford Hip Scores improved from an average of 8 (1–17) preoperatively to an average of 36 (18–45) at the last follow-up. WOMAC scores preoperatively averaged 76 (49–96) and postoperatively averaged 26.5 points (0–69) at the last follow-up. SF-12 scores improved in both components. One patient showed non-progressive osteolysis around the ischial flange and one had less than 5 mm migration of the construct. One patient died of unrelated causes. ConclusionOur study presents one of the longest follow-up of cup-cage construct and supports the previously reported good results; it encourages the use of this construct in reconstruction of massive acetabular defect, with or without pelvic discontinuity.

Multivariate analysis of risk factors for re-dislocation after revision for dislocation after total hip arthroplasty.

The treatment for recurrent dislocation of a total hip arthroplasty is surgical using varied techniques and technologies to reduce the chances of re-dislocation and re-revision. The goal of this study is to compare operative techniques to reduce re-dislocation and re-revision in revision hip arthroplasty due to recurrent dislocations. A retrospective study of revision hip arthroplasties done due to recurrent dislocation prior to 01 January 2014. Electronic physician and provincial health records were used to collect patients' initial and follow-up data. Treatment failure was defined as either aseptic re-revision or re-dislocation without revision. Time to event was considered as the re-revision date or the date of second dislocation when the latter endpoint was used. Of 379 operations, 88 (23.2%) had aseptic repeat revision or recurrent dislocation. Of these: 66 (75.0%) due to dislocation with re-revision; 10 (11.4%) due to dislocation with no re-revision surgery; 5 (5.7%) due to aseptic loosening of components; 3 (3.4%) due to osteolysis; 3 (3.4%) due to pseudotumour; and 1 (1.1%) due to periprosthetic fracture. The following factors increase risk of failure: the use of augmented-liners (lipped, oblique and high-offset liners; HR = 1.68, 95% CI, 1.05-2.69), periprosthetic femur fracture (HR = 2.80, 95% CI, 1.39-8.21) and pelvic discontinuity (HR = 3.69, 95% CI, 1.66-8.21). Femur head sizes 36-40 mm are protective (HR = 0.54, 95% CI, 0.31-0.86). In abductor dysfunction the use of focal constrained liners decreases the risk of failure (HR = 0.13, 95% CI, 0.018-0.973). Larger head sizes and focal constrained liners (abductors dysfunction) should be used and fully constrained liners and augmented-liners should be avoided in a revision hip arthroplasty due to recurrent dislocations.

Reconstruction of acetabular defects with porous tantalum shells and augments in revision total hip arthroplasty at ten-year follow-up.

The use of trabecular metal (TM) shells supported by augments has provided good mid-term results after revision total hip arthroplasty (THA) in patients with a bony defect of the acetabulum. The aim of this study was to assess the long-term implant survivorship and radiological and clinical outcomes after acetabular revision using this technique. Between 2006 and 2010, 60 patients (62 hips) underwent acetabular revision using a combination of a TM shell and augment. A total of 51 patients (53 hips) had complete follow-up at a minimum of seven years and were included in the study. Of these patients, 15 were men (29.4%) and 36 were women (70.6%). Their mean age at the time of revision THA was 64.6 years (28 to 85). Three patients (5.2%) had a Paprosky IIA defect, 13 (24.5%) had a type IIB defect, six (11.3%) had a type IIC defect, 22 (41.5%) had a type IIIA defect, and nine (17%) had a type IIIB defect. Five patients (9.4%) also had pelvic discontinuity. The overall survival of the acetabular component at a mean of ten years postoperatively was 92.5%. Three hips (5.6%) required further revision due to aseptic loosening, and one (1.9%) required revision for infection. Three hips with aseptic loosening failed, due to insufficient screw fixation of the shell in two and pelvic discontinuity in one. The mean Harris Hip Score improved significantly from 55 (35 to 68) preoperatively to 81 points (68 to 99) at the latest follow-up (p < 0.001). The reconstruction of acetabular defects with TM shells and augments showed excellent long-term results. Supplementary screw fixation of the shell should be performed in every patient. Alternative techniques should be considered to address pelvic disconinuity. Cite this article: Bone Joint J 2019;101-B:311-316.

Management of pelvic discontinuity in revision arthroplasty : Cementless acetabular cup with iliac stem and cranial strap.

Pelvic discontinuity causes severe destruction of the acetabular bony walls and is particularly difficult to manage. This article reports the short-term results and complications encountered in the management of loosening of the acetabular cup with pelvic discontinuity using an acetabular cup with an intramedullary iliac stem combined with an extramedullary iliac plate. As part of this monocentric retrospective case analysis all patients who underwent acetabular revision surgery after THR due to loosening of the acetabular cup with pelvic discontinuity in this clinic from January 2016 to June 2017 were identified (n = 16). All patients underwent routine clinical and radiological follow-up. In addition, the Harris hip score (HHS) and the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) were evaluated as part of a1-year follow-up. All patients were treated with an acetabular revision cup of appropriate size with intramedullary iliac stem combined with an anatomical extramedullary iliac plate. On clinical follow-up at 1 year (median follow-up time 14.5 ± 3.3months), the average HHS was 69.3 ± 14.1 and the average WOMAC was 79.3 ± 11.7. Complications were registered in 7 out of the 16patients whereby 1 showed aseptic loosening of the revision cup, dislocations were reported in 4cases and infections in 2cases. In the case of the two patients with infections aGirdlestone resection arthroplasty had to be performed. The overall complications and postoperative outcome in revision surgery after THR reported in the literature were compared to the results of this study. Compared to the results of salvage procedures using large or bipolar heads and Girdlestone resection arthroplasty, satisfactory results were obtained using the acetabular cup with an intramedullary iliac stem combined with an extramedullary iliac plate.

The use of pararectus approach for Type 3B Paprosky acetabular defect with intrapelvic cup migration. Case report.

Case: A case of Type 3B Paprosky acetabular defect with intrapelvic cup migration where anterior column plating and cup extraction was done through an abdominal pararectus approach.A male patient 63 years old reported progressive pain and walking disability after five years of cementless THR for right hip AVN.CT pelvis showed loose intrapelvic migrated cup, extensive osteolytic acetabular defects, and pelvic discontinuity.Pararectus approach was used to remove the cup and the head with concomitant plating of the anterior column Conclusion: The pararectus approach is a valid option for intrapelvic cup extraction and pelvic discontinuity fixation.

The augment-and-modular-cage revision system for reconstruction of severe acetabular defects-two-year clinical and radiographic results.

Acetabular revision of failed total hip arthroplasty (THA) is often associated with severe bone loss. Therefore, a variety of revision implant systems has been developed during recent years, with the augment-and-modular-cage system being one of the newest additions to this portfolio. Together with biologic downsizing by means of impaction bone grafting, this uncemented system promises a high modularity and versatility to treat all acetabular defects up to Paprosky types IIIa and IIIb without pelvic discontinuity. The aim of the present study was to evaluate first short-term results of its clinical application, both clinical functional and patient-reported as well as radiographic. Forty-four patients (28 female, 16 male, mean age 70.9 ± 11.5years) could be followed for a mean of 26 ± 10months after acetabular revision with a novel augment-and-modular-cage system. Indications for revision included aseptic loosening (68%), septic loosening (16%), or others (16%) with bone loss Paprosky IIa up to IIIb without discontinuity. The modified Harris Hip Score (mHHS) served as a primary outcome parameter. In addition, a number of patient-reported outcome measurements (PROMs) were collected including the Short Form 36 (SF-36), Hip disability and Osteoarthritis Outcome Score (HOOS), and Visual Analogue Scale for Hip Pain (VAS Hip) as well as overall satisfaction. Radiographic changes between the pre- and postoperative center of rotation (COR) and various criteria of implant failure served as secondary outcome parameters. No patients were lost to follow-up. Two implant-associated complications (partial flange breakage) without a need for revision surgery were detected, which represent a failure rate of 4.5%. Functional outcome as measured by mHHS increased from 49.4 ± 2.9 pre-operatively to 74.4 ± 3.1 at the latest follow-up (p < 0.001). PROMs showed significant improvements in all pain-related categories, while other quality-of-life measurements only exhibited positive tendencies towards improvement. VAS Hip significantly improved from 6.5 ± 0.7 pre-operatively to 2.2 ± 0.6 at the latest follow-up (p < 0.001). Radiographic evaluation showed that reconstruction of the COR was possible, referenced to the contralateral side. The COR could be lateralized by 5.0mm (n.s.) and caudalized by 10.3mm (p < 0.001) comparing pre-operative and post-operative states, with complete osseointegration in 95% of the cases. Treatment with the augment-and-modular-cage system significantly improved clinical functional and patient-reported outcomes in cases of acetabular revision after failed THA. In addition, a good reconstruction of the COR could also be achieved. Therefore, this highly modular system can be considered as an effective treatment option in almost all cases of acetabular bone loss except for those of pelvic discontinuity. It offers the unique possibility of intra-operative implant customization according to the existing bone defect and host bone quality.