Acetabular Reinforcement Ring Research Articles

Use of a custom‐made acetabular cage to treat aseptic loosening following cemented total hip replacement in a giant breed dog

AbstractA 7‐year‐old, female, spayed Dogo Argentino was presented with right hindlimb lameness 9 months following right total hip replacement. Investigations identified loosening of the acetabular cup and significant loss of bone stock, including defects of the dorsal acetabular rim and caudal pillar. A custom‐made acetabular cage inspired from the human acetabular reinforcement ring was implanted and fixed into the ilium and the acetabular rim with screws. Improvement in right hindlimb function was delayed by the occurrence of a right cranial cruciate ligament rupture; however, radiography 6 months following the surgery demonstrated osseointegration despite loosening of a single screw. Three years postoperatively, the dog showed no resentment on manipulation of the right hip and the owners reported a return to normal activity including off‐lead running. Aseptic cup loosening associated with acetabular medial wall and caudal pillar defect were ameliorated using a custom‐made acetabular cage in a giant breed dog.

Revision Total Hip Arthroplasty Utilizing an Acetabular Reinforcement Ring with a Metal Augment: A Minimum Eight-Year Follow-Up Study.

Background and Objectives: An acetabular reinforcement ring (ARR) with a structural allograft is conventionally used to treat large acetabular bone defects or discontinuity during revision hip arthroplasty. However, ARR is prone to failure due to bone resorption and lack of incorporation. Here, we investigated the surgical outcomes of the patients who underwent revision total hip arthroplasty (THA) using ARR combined with a metal augment (MA). Materials and Methods: We retrospectively reviewed data from 10 consecutive patients who had a minimum 8-year follow-up after revision hip arthroplasty using ARR with MA in Paprosky type III acetabular defect. We collected patient demographics, surgical details, clinical scores (including Harris Hip Score (HHS)), postoperative complications, and 8-year survival rates. Results: Six male and four female patients were included. The mean age was 64.3 years, and the mean follow-up duration was 104.3 months (96.0-112.0 months). Trauma-related diagnosis was the most common reason for index surgery. Three patients underwent all component revision, and seven underwent cup revision. Six were confirmed as Paprosky type IIIA and four as type IIIB. The mean HHS at the final follow-up was 81.5 (72-91). One patient was diagnosed with prosthetic joint infection at the 3-month follow-up; therefore, the minimum 8-year survival rate with our technique was 90.0% (95% confidence interval, 90.3-118.5%). Conclusions: The satisfactory mid- to long-term results of revision THA suggest that ARR combined with tantalum MA is a viable revision option for treating severe acetabular defects with pelvic discontinuity.

The Ganz acetabular reinforcement ring shows excellent long-term results when used as a primary implant: a retrospective analysis of two hundred and forty primary total hip arthroplasties with a minimum follow-up of twentyyears.

The acetabular reinforcement ring with a hook (ARRH) has been designed for acetabular total hip arthroplasty (THA) revision. Additionally, the ARRH offers several advantages when used as a primary implant especially in cases with altered acetabular morphology. The implant facilitates anatomic positioning by placing the hook around the teardrop and provides a homogenous base for cementing the polyethylene cup. Therefore, the implant has been widely used in primary total hip arthroplasty at our institution. The present study reports the long-term outcome of the ARRH after a minimum follow-up of 20years. Two hundredand ten patients with 240 primary THAs performed between April 1987 and December 1991 using the ARRH were retrospectively reviewed after a minimum follow-up of 20years. Twenty-three of 240 hips were lost to follow-up, 110 patients with 124 THAs had deceased without having a revision surgery performed. This left 93 hips for final evaluation. Of those, 75 hips were assessed clinically and radiographically after a mean follow-up of 23.1years (range 21.1-26.1years). In 18 cases, clinical and radiographic assessment was omitted because implant revision had been performed prior to the follow-up investigation. The primary endpoint was defined as revision for aseptic loosening. Out of the 93 hips available for final evaluation, 14 hips were revised for aseptic loosening; another four were revised for other reasons (deep infection n= 2, recurrent dislocation n= 2). The survival probability of the cup was 0.96 (95% confidence interval 0.93-0.99) after 20years with aseptic loosening as endpoint. Radiographic analysis of the surviving 75 hips showed at least one sign of radiographic loosening in 24 hips. The mean Merle d'Aubigne score increased from 8 points pre-operatively to 15 points at final follow-up (7.5 ± 1.8 vs 15.0 ± 2.3, p< 0.001). The mean HHS was 85 ± 14 at final follow-up. Radiographic loosening did not correlate with the clinical outcome. The long-term results of the ARRH in primary THA are comparable to results with standard cemented cups and modern cementless cups. We believe that the ARRH is a versatile implant for primary THA, especially in cases with limited acetabular coverage and altered acetabular bone stock where the ARRH provides sufficient structural support for a cemented cup.

Outcome of cages in revision arthroplasty of the acetabulum: a systematic review.

Background and aim of the work: To investigate the clinical, radiological and functional outcomes of acetabular revisions with acetabular reinforcement rings and cages. Methods: A comprehensive literature study of international databases was performed. Inclusion criteria were cementless revisions, use of reinforcement rings, radiological and clinical follow-up, availability of full text in English, publication between January 1990 and July 2018. In a second further analysis, we selected only studies describing patients with more severe acetabular defects (AAOS 3, AAOS 4, Paprosky III). Data extracted included mean follow-up period, radiographic follow-up, functional scores, implant failures and survival rate. Results: We included in our review 1327 acetabular revisions described in 28 articles. The most commonly used reinforcement rings were Burch-Schneider ring, the Muller ring and the Ganz ring. Mean follow-up for all patients together was 8.8 years. Clinical or radiological signs of loosening were reported in 191 patients, 83 patients needed further acetabular revision for aseptic loosening and 41 patients received additional surgeries for septic loosening. The mean value of the Harris Hip Score reported at the last follow-up was 76.3. Nineteen articles fulfilled the criteria for further analysis about high-grade acetabular bone defects. We analyzed 649 revisions with mean follow-up period of 8.2 years. Clinical or radiological loosening was reported in 90 patients, additional acetabular revision was performed in 39 patients and 25 patients needed further surgeries for deep infection. Conclusion: Acetabular revisions with cages are characterized by good survival rates and functional scores with a mean follow-up period of 8 years. (www.actabiomedica.it)

Acetabular reinforcement ring with additional hook improves stability in three-dimensional finite element analyses of dysplastic hip arthroplasty

BackgroundThe stability of acetabulum reconstructions using reinforcement rings and hooks is important for successful replacement surgery. The objective of this study was to biomechanically determine the effects of the hook on stress and the related micromotions of the acetabular reinforcement ring during the immediate postoperative period.MethodsAcetabular reinforcement ring models were developed using a nonlinear, three-dimensional, finite element method. Using a pre-prepared template, we constructed without-hook and bone graft models of varying volumes and material properties.ResultsThe stress on the inferior margin of the acetabulum was higher in the with-hook model than in the without-hook model, especially with increased bone graft volumes, and the stiffness of the bone graft material was decreased. Relative micromotions in the without-hook model were higher than in the with-hook models. The highest relative micromotion was observed in the model with increased bone graft volume and lower stiffness of bone graft material.ConclusionsIn biomechanical analyses, the hook effectively dispersed stress and improved the initial fixation strength of the acetabular reinforcement ring.

Long-term results of isolated acetabular revisions with reinforcement rings: a 10- to 15-year follow-up.

The management of severe acetabular bone deficiency and a stable femoral stem can be a challenging problem in revision hip surgery. Replacement of both the acetabular and femoral component in elderly patients can increase perioperative risks without the certainty of a better functional outcome. We report the long-term outcome of reinforcement rings in isolated acetabular revision to determine whether this procedure allows hip function restoration and implant longevity. A retrospective study was conducted to evaluate the long-term results of isolated acetabular revision in thirty patients with a mean age of 70.6 years. 16 patients (16 hips) received an acetabular reinforcement ring, and 14 patients received a reconstruction cage. Acetabular defects were classified as Paprosky Type II in 16 cases and Type III in 14 cases. The mean follow-up was 11.3 years (range 10-15 years). Radiographic signs of loosening were found in 9 cases (30%). 4 cases (13.3%) with severe osteolysis and implant migration underwent further revision surgery. All 30 unrevised femoral stems were considered stable. 1 (3%) early dislocation, was conservatively treated. Clinical assessment showed a significantly improved mean Harris Hip Score from 45.1 points preoperatively to 85.4 at the latest follow-up (p < 0.05). The 15-year survival rate was 86.7%. Our long-term results showed that in selected patients, isolated acetabular revision with rings or antiprotrusio cages represents a reasonable surgical technique for the management of severe acetabular bone loss. However, concerns about the high radiographic loosening rates are possibly related to low bone ingrowth compared to new porous implants.

Acetabular reinforcement rings associated with allograft for severe acetabular defects.

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.

Long-Term Results of Acetabular Reconstruction Using Ganz Acetabular Rings

BackgroundOur study examines the long-term results of acetabular reconstruction using the Ganz acetabular reinforcement ring (GRR) in total hip arthroplasty. MethodsBetween 1998 and 2001, 135 hips (119 revision and 16 primary arthroplasties) were consecutively implanted with a GRR at our hospital. The average age was 65 years (range, 26-90). Clinical and radiographic evaluations were carried out. Long-term survivorship was estimated using a competing risks analysis, and multivariate survivorship using Cox regression model was used to identify risk factors for implant failure. ResultsAt a mean follow-up of 16 years (range, 15-18), 3 patients were lost to follow-up and 19 had implant failure: 4 aseptic loosenings without re-revision, 4 septic, and 11 aseptic re-revisions. Survival was estimated at 86% after 16 years (95% confidence interval [CI], 78.5%-90.9%) using radiographic loosening or revision for any reason as the end point. Using aseptic loosening as the end point, the survival was estimated at 91.2% after 16 years (95% CI, 84.5%-95.0%). Multivariate analysis revealed that age at surgery was a significant risk factor for failure of the GRR. With acetabular revision or loosening as the end point, patients ≤60 years had 71.6% (95% CI, 53%-82.8%) and older patients had 92.2% (95% CI, 84%-96.2%) probability of implant survival after a mean 16-year follow-up. The median Harris Hip Scores and Western Ontario and McMaster Universities Osteoarthritis Index scores were 77 and 64.5, respectively, and mean Numerical Pain Rating Scale score was 1.6 at final follow-up. ConclusionOur long-term study showed acceptable survival and functional results using the GRR in older patients, while young patients had less favorable survival.

Application of acetabular reinforcement ring with hook for correction of segmental acetabular rim defects during total hip arthroplasty revision

This study investigated the biomechanical micro-motion associated with the application of acetabular reinforcement ring with hook (Ganz ring) for the correction of segmental acetabular rim defects, by finite element analysis. The objective was to determine whether the Ganz ring is suitable for correcting segmental acetabular rim defects at different regions during total hip arthroplasty revision as well as the number of screws required to fix the Ganz ring. A finite element model of the hip joint was generated to simulate and evaluate the insertion and fixation of the Ganz ring and acetabular cup in the context of segmental rim defects in the anterior column, superior portion, and posterior column. Micro-motion was the greatest in the posterior column defect and the least in the anterior column defect. However, the peak stress distribution on the remaining portion of the acetabular rim was the highest in the superior portion defect, following the posterior column defect and anterior column defect. Increasing the number of fixations of the Ganz ring did not decrease the micro-motion. We found that the Ganz ring effectively provided biomechanical stability during the reconstruction of the segmental rim defect as long as the screws fixed the Ganz ring well to the host bone.

Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision

Background and purpose — The original Müller acetabular reinforcement ring (ARR) was developed to be used for acetabular revisions with small cavitary and/or segmental defects or poor acetabular bone quality. Long-term data for this device are scarce. We therefore investigated long-term survival and radiographic outcome for revision total hip arthroplasty using the ARR.Patients and methods — Between October 1984 and December 2005, 259 primary acetabular revisions using an ARR were performed in 245 patients (259 hips). The mean follow-up time was 10 (0–27) years; 8 hips were lost to follow-up. The cumulative incidence for revision was calculated using a competing risk model. Radiographic assessment was performed for 90 hips with minimum 10 years’ follow-up. It included evaluation of osteolysis, migration and loosening.Results — 16 ARRs were re-revised: 8 for aseptic loosening, 6 for infection, 1 for suspected infection, and 1 due to malpositioning of the cup. The cumulative re-revision rate for aseptic loosening of the ARR at 20 years was 3.7% (95% CI 1.7–6.8%). Assuming all patients lost to follow-up were revised for aseptic loosening, the re-revision rate at 20 years was 6.9% (95% CI 4.1–11%). The overall re-revision rate of the ARR for any reason at 20 years was 7.0% (95% CI 4.1–11%). 21 (23%) of the 90 radiographically examined ARR had radiographic changes: 12 showed isolated signs of osteolysis but were not loose; 9 were determined loose on follow-up, of which 5 were revised.Interpretation — Our data suggest that the long-term survival and radiographic results of the ARR in primary acetabular revision are excellent.

Isolated acetabular revision with femoral stem retention after bipolar hip arthroplasty.

In bipolar hemiarthroplasty, migration of the outer cup component into the acetabular cup, with evidence of severe osteolysis in the acetabulum, commonly occurs without loosening of the femoral component. The merits of retaining the stable femoral component in these cases have been debated. Our study aimed to determine whether revision of the acetabular component in isolation could be successfully performed. The data of 54 patients (61 hips), 44 women, and 10 men, aged 67.7 (range 47-86) years at the time of the index revision, were analyzed. The average time from primary operation to revision surgery was 14.9 (range 1.0-27.0) years, with an average follow-up time after revision of 5.2 (range, 1.0-18.7) years. Indications for acetabular revision included migration of the outer cup component (N = 55), disassembly of the bipolar cup (N = 4), and recurrent dislocation (N = 2). Fixation of the femoral stem was cementless in 49 hips and cemented in 12. Bone grafting for osteolysis of the proximal femur around the stem was performed in six hips. An acetabular reinforcement ring with a cemented cup was used in 31 hips, with cementless cup fixation in 29 hips, and cemented cup in one case. On average, the Harris hip score improved from 57.0 ± 21.6 to 87.4 ± 6.40 points after revision. Two cases of femoral periprosthetic fracture were treated with osteosynthesis 3year post-revision. There was no evidence of loosening of the femoral stem or subsidence, with a non-progressive radiolucent line <2mm identified in one case. There was no incidence of dislocation or deep infection, and all components were judged to be stable at the final follow-up. Isolated acetabular revision can be reliably performed in cases of failed bipolar hemiarthroplasty with a well-fixed femoral component.

Mid-term outcomes of revision hip arthroplasty for severe acetabular bone defects

Objective To evaluate the mid-term clinical and radiographic outcomes of acetabular revision for Paprosky IIIA or IIIB acetabular bone defects. Methods Thirty consecutive acetabular revisions were conducted with allograft bone transplant, metal augment or reinforcement combined with cement or cementless cup in 29 patients with a severe Paprosky III acetabular bone defects from January 2002 to June 2012. There were 17 males and 12 females with average age 64.7±2.9 years. Eleven hips had acetabular reconstruction using cementless cup and augment, nineteen hips were revised using allograft bone transplant, acetabular reinforcement ring and cement cup. Hip function of patient was evaluated by Harris score at pre- and post operation. The outcomes of acetabular prostheses and bone grafts were assessed by radiographic analysis. The 10-years components survival rate was assessed by Kaplan-Meier survivorship analysis. Results Twenty-seven patients (28 hips) had a minimum 4-year follow-up, ranged from 4.4 to 11.8 years (6.8 years on the average). The average Harris score improved from pre-operative 31.4±5.7 to 88.3±3.9 at the final follow-up (t=6.392, P <0.001). The leg discrepancy was improved from preoperative 28.4±10.2 mm to postoperative 1.4±2.8 mm (t=7.391, P <0.001). The hip rotation center was reconstructed from preoperative 35.3±6.4 mm to postoperative 3.2±5.8 mm (t=9.427, P <0.001) lateral-toward dislocation to inside Ranawat triangle. The allograft bone was incorporated with the host bone during 6 months to 2 years postoperatively. Radiographic analysis of all 28 hips showed that there was no component loosening, and among of them, 5 hips had a non-progressive radiolucent line. No screw or cement fracture and no cage displacement occurred. There was no moderate or severe bone absorption at the final follow-up. Kaplan-Meier analysis demonstrated that a ten-year component survival rate was 100% (95%CI: 0.95, 1.00). Conclusion In hip revision surgery, most of Paprosky IIIA acetabular bone defects are characterized by continuous acetabulum and relative intact of anterior and posterior column, which is suitable to take metal augment and cement cup to reconstruct. Most of Paprosky IIIB acetabular bone defects have discontinuous acetabulum and severe destruction of anterior/posterior column. Restoration hip rotating center and satisfied midterm outcomes benefit from allograft bone transplant combined with acetabular reinforcement ring and cement cup. Key words: Arthroplasty, replacement, hip; Reoperation; Acetabulum; Osteolysis; Bone transplantation; Tantalum

Revision Total Hip Arthroplasty Using an Acetabular Reinforcement Ring With a Hook: A Precise Follow-Up, at Average 11.4 Years, of a Previous Report

BackgroundThis study aims at determining the average long-term result of revision total hip arthroplasty (THA) using the acetabular reinforcement ring with a hook (ARRH) and bone grafting in severe acetabular bony defect. Expected 15-year survival of ARRH in revision THA is included in the study. MethodsRetrospective review of 48 patients (48 hips) with follow-up duration of average 11.4 years (range, 6.1-21.4 years) was conducted. At each follow-up, Harris hip score was used to assess functional outcome, and radiographic acetabular component osteolysis was measured by DeLee and Charnley classification. Bone defects were assessed preoperatively and intraoperatively using American academy of orthopedic surgeons and Paprosky classification. The common modes of ARRH failures were evaluated. Bone consolidation, presence of heterotopic ossification, and complications such as infection and dislocation were recorded. ResultsThe bone defects were varied and included cavitary, segmental, and combined defects without any pelvic discontinuity. Mean Harris hip score improved from 52.6 points preoperatively to 82.0 points postoperatively. Nine acetabular revisions and 3 stem revisions (2 concurrent with acetabular revisions and 1 isolated stem revision) were performed. There were 5 infected cases and 1 patient with recurrent dislocation. The 11.4-year survival of revision THA with ARRH was 71% as the end point for acetabular revision surgery for any reason. The expected 15-year survival of revision THA with ARRH was 60%. The most common failure mode of ARRH was superomedial migration followed by lateral migration. ConclusionARRH combined with bone grafting produces relatively good average long-term clinical results.

Excellent long-term results of the Müller acetabular reinforcement ring in primary total hip arthroplasty

Background and purpose — The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure.Patients and methods — Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0–25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening.Results — 12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10–22), while for the ARR only it was 7% (95% CI: 4–12) for any reason and 3.4% (95% CI: 1–9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised.Interpretation — Our data suggest that the long-term survival of the ARR is excellent.

One-stage revision of infected hip arthroplasty: outcome of 39 consecutive hips

There are various options for treating periprosthetic joint infection (PJI). Two-stage exchange has traditionally been the gold standard. However, if the appropriate surgical intervention is chosen according to a rational algorithm, the outcome is similar when using all types of interventions. In an observational cohort study, the outcome of patients with PJI after hip replacement treated with one-stage revision was analysed. All patients fulfilling all criteria for one-stage exchange according to the Infectious Diseases Society of America (IDSA) guidelines and six without preoperative identification of a microorganism were included. Implant removal, debridement and cemented or uncemented reimplantations were performed in a single intervention. If a cemented device was implanted, commercially available gentamicin cement was used in all cases. Antibiotic treatment was administered intravenously for at least 2weeks, followed by oral therapy for a total duration of 3months. Patients had standardised clinical and radiological follow-up visits. Between 1996 and 2011, 38 patients (39 hips) were treated with a one-stage procedure and followed for at least 2years. Coagulase-negative staphylococci were the most frequent pathogens, and polymicrobial infection was observed in five cases. In 25 hips, an uncemented revision stem was implanted, and 37 hips received an acetabular reinforcement ring. The mean follow-up was 6.6 (2.0-15.1) years. No patient had persistent, recurrent or new infection. There were four stem revisions for aseptic loosening. The mean Harris Hip Score was 81 points (26-99) at the final follow-up. Excellent cure rate and function seen in our study suggest that one-stage exchange is a safe procedure, even without local antibiotic treatment, provided that the patient has no sinus tract or severe soft tissue damage, no major bone grafting is required and the microorganism is susceptible to orally administered agents with high bioavailability.

Acetabular Reconstruction with Reinforcement Ring and Morsellised Graft: Technique and Medium-term Result: 以髖臼加強環及切碎骨來重建髖臼 - 技術及中期結果

BackgroundAcetabular bone defects are commonly seen in both primary and secondary total hip arthroplasty, creating difficulties in restoring anatomical hip centres, which results in high mechanical failure rate. MethodsTotal hip arthroplasty with acetabular reinforcement rings were performed in 18 hips in 18 patients from 1996 to 2011 in United Christian Hospital. Both clinical and radiographical assessment were performed during follow-up. ResultsEight patients died of unrelated diseases with average follow-up of 30.5 months. At the latest follow-up, none of them showed radiographic signs of loosening or migration of implants and none of them required revision surgery. The remaining 10 patients with mean age of 77.9 years (range, 65–88) at the time of operation were followed-up for an average of 67.4 months (range, 11–121). The average Harris hip score was 78.3 (range, 58.5–87). The average vertical and horizontal difference of hip centres was 1.5 mm superiorly (p = 0.431) and 0.4 mm medially (p = 0.619) respectively when postoperative hip centres were compared to their contralateral hips. The average inclination of the polyethylene cup was 47.8 degrees (range, 42–58). There was no evidence of radiographic loosening during our follow-up and none of them required revision surgery. ConclusionAcetabular reconstruction with the use of acetabular reinforcement rings and morsellised bone grafts showed satisfactory clinical and radiographic results at a medium-term follow-up.

10-Year Survival of Acetabular Reinforcement Rings/Cages for Complex Hip Arthroplasty.

Introduction : Acetabular reinforcement rings/ cages (AR) are commonly used for reconstruction of bone defects in complex hip arthroplasty. The aim of this study was to retrospectively investigate the 10-year survival rate of Ganz reinforcement rings and Burch-Schneider cages used in a single institution.Material and Methods : Between September 1999 and June 2002 all ARs, implanted in one institution, were identified. All patients had regular clinical and radiographic follow-up and were included in this study. Their prospectively collected clinical and radiographic data was retrospectively analyzed. In case of death before the 10-year follow-up examination, patient’s families or their general practitioner was contacted by telephone. The main outcome measures were survival of the ARs and kind of revision surgery.Results : The 10-year survival rate was 77.7%. At 10-year follow-up, 5/60 (8,3%) patients could not be located and had to be excluded therefore. 27/55 (49,1%) were dead, whereof 22 had no revision of the ARs before death (after a mean of 66 months; range: 0 - 123). Of the remaining 28/55 (50,9%) patients, 23 patients (24 ARs) had no revision of the ARs.Conclusion : Despite the high mortality rate of this study’s collective, ARs for complex primary or revision total hip arthroplasty provided predictable long term results.Level of Evidence : Clinical investigation.

Reconstruction of advanced periacetabular metastatic lesions with modified Harrington procedure.

The purpose of this study was to assess the outcomes of patients who had been treated by a modified Harrington procedure for advanced periacetabular metastases. Between 2006 and 2013, 16 patients with a mean age of 57 years (range: 28-73 years) were treated using a modified Harrington technique. Extensive (class II/III) periacetabular defects were due to metastatic carcinoma or multiple myeloma. Surgical procedure included total hip replacement and acetabular reconstruction using threaded pins, cemented acetabular reinforcement ring, and/or polyethylene cup. All patients improved in regard to pain and walking ability. Mean preoperative and postoperative Musculoskeletal Tumour Society (MSTS) functional scores were 52.8% (range: 33.3-73.3%) and 72% (range: 56.6-90%), respectively (p<0.05). There were 5 (31%) early or late complications requiring additional surgery. Implant survival was 75% and 37.5% at 12 and 18 months, respectively. Mean survival of the patients was 21 months (range: <1-6 years). Six remained alive, with a mean survival of 27 months (range: 18 months to 5 years). This modified Harrington procedure can be used for reconstruction of advanced periacetabular metastatic lesions.

Acetabular Fractures in the Elderly Treated With a Primary Burch–Schneider Reinforcement Ring, Autologous Bone Graft, and a Total Hip Arthroplasty

To investigate the clinical and radiologic outcomes in elderly patients suffering from an acetabular fracture operated with an acute primary acetabular reinforcement ring, autologous bone graft, and a total hip arthroplasty (THA). Prospective cohort study. Tertiary care university hospital. Fifteen elderly patients (7 women) with a mean age of 76 years and a displaced acetabular fracture after a low-energy trauma were included. The fractures involved the anterior column, but no patients with associated both column fractures were included. All the patients were able to walk independently before the fracture occurred. Primary operation with a Burch-Schneider reinforcement ring, autologous bone graft, and a THA. The patients were reviewed at 4, 12, 24, and 48 months after the fracture occurred. The outcome assessments included complications, reoperations, activity of daily living function, functional scores (Harris hip score and short musculoskeletal function assessment), health-related quality of life [EuroQol (EQ-5D) index score], and radiologic evaluation. There were no prosthetic dislocations, periprosthetic fractures, deep infections, or other adverse events. There were no radiologic signs of loosening of the reinforcement ring or the prosthesis components at any of the follow up sessions, and the autologous bone graft was well incorporated in all the patients at the final follow-up. At 48 months, the mean Harris hip score was 88, the mean short musculoskeletal function assessment dysfunction score was 30, the bother score was 25, and the mean EQ-5D index score was 0.65. All the patients were able to walk independently at the final follow-up. Treatment of displaced anterior column, anterior column posterior hemitransverse and transverse acetabular fractures in elderly patients using a primary reinforcement ring, autologous bone graft, and a THA seems to be a safe option with good functional and radiologic outcomes. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Effect of Acetabular Reinforcement Ring With Hook for Acetabular Dysplasia Clarified by Three-Dimensional Finite Element Analysis

The objective of this study was to biomechanically determine the effect of the severity of acetabular dysplasia, number and positions of screws and type of bone graft material used on the initial fixation strength of the acetabular reinforcement ring with hook (Ganz ring) using the finite element method. Relative micromotion increased as the severity of acetabular dysplasia increased and tended to decrease as the number of screws increased, but varied according to screw placement position. Increased strength of the bone graft material led to decreased relative micromotion. Biomechanically, the Ganz ring can be placed securely using 3 screws in patients with Crowe 1 dysplasia. However, in patients with Crowe 2 or higher dysplasia, it is necessary to spread at least 4 screws across an area of good host bone.