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

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

BACKGROUND

A 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.

METHODS

The 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.

RESULTS

Overall, 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).

CONCLUSION

The 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.

Acetabular defect classification and management : Revision arthroplasty of the acetabular cup based on 3-point fixation

BACKGROUND

The purpose of this study was to provide a practicable and contemporary classification system that is reliable and pragmatic with respect to perioperative evaluation, planning, scientific comparison and analysis.

MATERIAL AND METHODS

This was a retrospective study of 160 patients who underwent acetabular revision surgery after THR due to loosening of the acetabular cup. The assessment of the acetabular defect was based on intraoperative description of the bony configuration of the acetabulum as well as on standardized preoperative planning images (pelvic overview and axial view of the hip joint). Preoperative computed tomography (CT) was carried out in individual cases.

RESULTS

Acetabular bone defects were classified into 4 types based on whether or not a 3-point fixation of the acetabular cup within the boundaries of the acetabular cavity was possible. Minor segmental defects or cup loosening without bone loss can be treated with standard hemispherical acetabular components. Bone loss can be filled with bone grafts and/or treated by the appropriate acetabular component in order to ensure stable anchorage. When conventional revision cups are no longer suitable a custom made partial pelvic replacement can be used.

CONCLUSION

The proposed classification mainly relies on intraoperative findings which were confirmed by preoperative imaging in 154 cases out of 160 (96.25%); however, meticulous preoperative planning based on X‑ray radiographs must be carried out. In addition, a CT scan must be performed whenever type III or type IV defects are anticipated. Compared to the existing classification systems, we can state that our classification system is practicable and pragmatic and simplifies the assessment of bone defects.

Acetabular defects in revision hip arthroplasty: a therapy-oriented classification

INTRODUCTION

The treatment of severe acetabular bone loss remains a difficult challenge. No classification system is available that combines intuitive use, structured design and offers a therapeutic recommendation according to the current literature and modern state of the art treatment options. The goal of this study is to introduce an intuitive, reproducible and reliable guideline for the evaluation and treatment of acetabular defects.

METHODS

The proposed Acetabular Defect Classification (ADC) is based on the integrity of the acetabular rim and supporting structures. It consists of 4 main types of defects ascending in severity and subdivisions narrowing down-defect location. Type 1 presents an intact acetabular rim, type 2 includes a noncontained defect of the acetabular rim ≤ 10 mm, in type 3 the rim defect exceeds 10 mm and type 4 includes different kinds of pelvic discontinuity. A collective of 207 preoperative radiographs were graded according to ADC and correlated with intraoperative findings. Additionally, a randomized sample of 80 patients was graded according to ADC by 5 observers to account for inter- and intra-rater reliability.

RESULTS

We evaluated the agreement of preoperative, radiographic grading and intraoperative findings presenting with a k value of 0.74. Interobserver agreement presented with a k value of 0.62 and intraobserver at a k value of 0.78.

CONCLUSION

The ADC offers an intuitive, reliable and reproducible classification system. It guides the surgeon pre- and intraoperatively through a complex field of practice.