Acetabular Reconstruction Cage Research Articles

Biomechanical Analysis of a Novel Acetabulum Reconstruction Technique with Acetabulum Reconstruction Cage and Threaded Rods after Type II Pelvic Resections.

Background. Periacetabular resections with reconstruction has high rates of complications due to the complexity of the reconstruction. We have improvised a novel technique of reconstruction for type II and type II + III pelvic resections with the use of a commercially available acetabulum reconstruction cage (gap II, Stryker) and threaded rods. Objectives. The aim of our study is to determine the biomechanical strength of our reconstruction compared to the traditional cemented total hip replacement (THR) designs in normal acetabulum and establish its mode of failure. Methods. Five sets of hemipelvises were biomechanically tested (Instron® 3848, MA, USA). These constructs were subjected to cyclic loading and load to failure. Results. The reconstructed acetabulum was stiffer and required a higher load to failure compared to the intact pelvis with a standard THR. The mean stiffness of the reconstructed pelvis was 1738.6 ± 200.3 Nmm−1 compared to the intact pelvis, which was 911.4 ± 172.7 Nmm−1 (P value = 0.01). The mean load to failure for the standard acetabular cup construct was 3297.3 ± 117.7 N while that of the reconstructed pelvis with the acetabulum cage and threaded rods was 4863.8 ± 7.0 N. Conclusion. Reconstruction of the pelvis with an acetabular reconstruction cage and threaded rods is a biomechanical viable option.

The role of cages in the management of severe acetabular bone defects at revision arthroplasty.

An uncemented hemispherical acetabular component is the mainstay of acetabular revision and gives excellent long-term results. Occasionally, the degree of acetabular bone loss means that a hemispherical component will be unstable when sited in the correct anatomical location or there is minimal bleeding host bone left for biological fixation. On these occasions an alternative method of reconstruction has to be used. A major column structural allograft has been shown to restore the deficient bone stock to some degree, but it needs to be off-loaded with a reconstruction cage to prevent collapse of the graft. The use of porous metal augments is a promising method of overcoming some of the problems associated with structural allograft. If the defect is large, the augment needs to be protected by a cage to allow ingrowth to occur. Cup-cage reconstruction is an effective method of treating chronic pelvic discontinuity and large contained or uncontained bone defects. This paper presents the indications, surgical techniques and outcomes of various methods which use acetabular reconstruction cages for revision total hip arthroplasty.

CORR Insights(®): Custom Acetabular Cages Offer Stable Fixation and Improved Hip Scores for Revision THA With Severe Bone Defects.

T he ideal reconstructive method for the severely deficient acetabulum in revision THA remains unsolved. Severe acetabular deficiencies may be evaluated by the Paprosky et al. [7] grading system from which both the anticipated bony defects and the reconstruction needs may be identified. Fortunately, the incidence of severe acetabular deficiency is low, with a report from the Mayo Clinic finding that Paprosky IIIB defects occurred in only 0.9% of hips (31/3505) undergoing revision acetabular surgery at that tertiary care center between 1969–1995 [1]. Most acetabular reconstructions are performed with a large hemispherical shell with a survivorship range of 94% to 100% at midto long-term followup [2]. For acetabuli with greater bony loss, porous metal augments may be added, allowing the creation of a bony and metal concavity supportive of a hemispherical shell. As the defect worsens, more-elaborate options come into the picture, perhaps including custom acetabular cages (or triflange cups), reconstruction cages, cup-cage constructs, or cup-cup constructs. Surgeons must recognize the high surgical complexity when contemplating using one of these approaches, as complications can be severe, and unrecognized or untreated pelvic discontinuities can result in a high risk of failure. During more than a 10-year period, the authors of the current study reported the surgical treatment of 26 patients (all with Type IIIB defects, four with a pelvic discontinuity) who underwent acetabular reconstruction using a gritblasted titanium custom cage. At a mean followup of 67 months (range, 24 months to 120 months) in 24 patients only one cage was felt to be possibly loose, and the authors reported the appearance of particulate allograft incorporation in 23 of 24 patients. One important caveat of this study is that this was the first revision surgery for all but one patient. We can compare the results in this series to other reports about severe acetabular defects, which used other approaches, namely reconstruction cages, or custom triflange cups. In a single-surgeon series, reconstruction cages failed in 24% of reconstructions at mean 4.6-year followup, with the highest failure rates occurring in 10 hips with American Academy of Orthopaedic Surgeons (AAOS) Type This CORR Insights is a commentary on the article ‘‘Custom Acetabular Cages Offer Stable Fixation and Improved Hip Scores for Revision THA With Severe Bone Defects’’ by Li and colleagues available at: DOI: 10.1007/s11999-015-4587-0. The author certifies that he, or any member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at DOI: 10.1007/s11999015-4587-0.

複合材料製寛骨臼サポートコンポーネントのモデリングと骨-インプラント系への影響評価

複合材料製寛骨臼サポートコンポーネントのモデリングと骨-インプラント系への影響評価

Revision total hip arthroplasty using a reconstruction cage device and a cemented dual mobility cup

The main causes of total hip arthroplasty (THA) revisions are loosening and instability. Dual mobility cups were introduced to prevent instability, but their behavior during revisions with acetabular reconstruction has not been assessed. Use of a dual mobility cup cemented in a acetabular reconstruction cage device limits the risk of instability and does not hinder the acetabular fixation during THA revisions. The objective of this study was to test this hypothesis on a retrospective series of 96 revisions. At a mean follow-up of 41 months (range, 1-101 months), we analyzed a continuous series of 96 revisions using a reconstruction device (70 Kerboull™ cross-plates, six Burch-Schneider™ antiprotrusio cages, 20 custom-fit Novae ARM™ cages associated in all cases with a Novae Stick dual mobility cup cemented into the cage). Fifteen patients died at a mean follow-up of 22 months (range, 1-66 months) and four patients were lost to follow-up at a mean follow-up of 16 months (range, 9-27 months). These were acetabular revisons involving major bone loss, with 62 stage III and 26 stage IV cases on the SOFCOT classification. Eighty-seven patients (87.5%) underwent structural bone allografting. The mean Merle d'Aubigné score increased from 9.6 ± 3.06 (range, 2-16) preoperatively to 15.5 ± 2.32 (range, 7-18) at the follow-up. Ten dislocations (10.4%) occurred, five of which were delayed over three months after the index procedure (5.2%), but there were no intraprosthetic dislocations. At the follow-up, the X-rays showed eight hardware failures, including one cross-plate fracture, one hook fracture, and one flange fracture. Analysis of the radiological position of the cup showed a mean lowering of 15.6mm and a 9.4mm lateralization compared to the preoperative position. One revision for aseptic loosening and another for septic loosening were performed. Taking all-cause acetabular component exchange as a criterion, the survival rate at 8 years was 95.6% (95% CI, 93.3-97.7%) and 99.3% (95% CI, 98.9-99.6%) if the endpoint was aseptic acetabular exchange. This study confirms the advantage of dual mobility cups during acetabular reconstruction cemented in antiprotrusio cages as a way to limit, without eliminating, the risk of dislocation. Therefore cemented fixation of dual mobility cups in cages appears to be a reliable short-term option.

Does a Cemented Cage Improve Revision THA for Severe Acetabular Defects?

BackgroundEvidence suggests a growing incidence of revision total hip arthroplasty (THA) including a subset with large acetabular defects. Revision THA for severe acetabular bone loss is associated with a relatively high rate of mechanical failure.Questions/purposesWe questioned whether cementing a cage to the reconstructed acetabular defect and pelvis would improve the rate of mechanical failure for patients with Type 3 defects (Paprosky et al.) with and without pelvic discontinuity in comparison to historical controls.MethodsWe retrospectively collected data on 33 patients who underwent 35 revision THAs using an acetabular reconstruction cage cemented to morselized allograft and either structural allograft or trabecular metal augmentation for Type 3 defects in the presence (n = 13) and absence (n = 22) of pelvic discontinuity at a mean followup of 59 months (range, 24–92 months). The primary outcome was mechanical failure, defined as revision of the acetabular reconstruction for aseptic loosening.ResultsRevision surgery for mechanical failure occurred in four of the 13 patients with pelvic discontinuity and two of the 22 patients without discontinuity. Radiographic loosening occurred in one patient with and one patient without pelvic discontinuity. Seven of the 35 revisions were subsequently revised for deep infection all in patients who were immunocompromised.ConclusionsCementing the cage to the pelvis can offer an advantage for treating severe acetabular defects. Trabecular metal augmentation appears to provide better initial mechanical stability than a structural allograft, but successful allograft reconstruction may restore bone stock.Level of EvidenceLevel IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Rapid Failure of Cup in Total Hip Arthroplasty

Early failure, of cemented acetabular cup due to cup breakage in Total Hip Arthroplasty is extremely rare. Revision surgery to deal with bone loss, associated with cup failure, is challenging to treat surgically and requires acetabular reconstruction cage & massive bone allografts.

Late Transection of the Sciatic Nerve in Association With an Acetabular Reconstruction Cage

We report a case of a late-onset sciatic nerve palsy that occurred in association with an acetabular reconstruction cage. On surgical exploration, the nerve was found to be completely transected secondary to abrasion over the posterior flange of the reconstruction cage.

The Anatomy of the Acetabulum: What is Normal?

Published studies of the human hip make frequent reference to the normal pelvis and acetabulum. However, other than qualitative descriptions we found no clinically applicable published references describing a normal pelvis and acetabulum; such information is important for designing certain kinds of implants (eg, reconstruction cages). We describe a method to quantify, average, and apply data gathered from normal human specimens to create a standard representation of the ilium and ischium. One hundred healthy hemipelves from 50 human skeletons were evaluated. We measured angles and distances between major anatomic landmarks in the pelvis. The data collected were analyzed for variance and averaged to create a normal topographic map. Finally, we examined several commercially available acetabular reconstruction cages to determine the fit to the anatomically determined normal pelvis. These results provide a representation of true acetabular geometry and may serve as the basis for future acetabular reconstruction cage design.

Morsellized Allograft and Acetabular Reconstruction Cage: Follow-up of 2 to 9 years

We report the outcome of 32 patients who underwent total hip replacement (THR) augmented with morsellized fresh frozen femoral head allografts and acetabular reconstruction cages. Nine patients underwent primary THR and 23 patients underwent revision THR. Follow-up ranged from two to 9 years. Two most common indications for the procedures as reported in literature were rheumatoid arthritis and aseptic loosening of the hip. All but one patient achieved good outcome with radiographs showing full incorporation of bone grafts and no evidence of loosening of the implants. Morsellized bone grafting used with acetabular reinforcement devices is valuable for addressing severe acetabular deficiencies.

Neurovascular Injuries in Acetabular Reconstruction Cage Surgery: An Anatomical Study

Acetabular reconstruction cages are indicated for severe combined segmental and cavitary acetabular bone defects. The purpose of this study was to evaluate the implications of screw placement and drill plunge and the potential insult to anatomical structures when implanting acetabular reconstruction cages. A segmental cavitary defect was reamed into the acetabulum and a cage was implanted in each of the 10 hemipelvises. The relative course of the superior gluteal neurovascular bundle was mapped to assess dissection intervals. When cage screws were placed at least 15 mm longer than needed, 13% and 20% of screws of the superior flange and anterior rim hit the femoral nerve, respectively, and approximately 60% of the screws placed in the posterior rim endangered the obturator nerve. A “safe zone” for screw size may be a 15- and 25-mm screw for the superior flange and posterior rim, respectively.

Fixation using acetabular reconstruction cage and cancellous allografts for intraoperative acetabular fractures associated with cementless acetabular component insertion

Displaced acetabular fractures that occur during insertion of cementless acetabular component are a rare but very serious complication. We report two cases that were treated successfully with the utilization of an acetabular reconstruction cage and morsellized allografts.