What Are the Options for Managing Pelvic Discontinuity?
Dr. Christopher Melnic and Dr. Scott Sporer answer questions from ICJR about managing patients who present with acute or chronic pelvic discontinuity.
ICJR: How common is pelvic discontinuity in failed total hip arthroplasty (THA) patients, and what causes it?
Christopher M. Melnic, MD: A pelvic discontinuity occurs when there is a separation between the inferior and superior hemipelvis. Fortunately, the incidence of pelvic discontinuity is low, ranging from 1% to 5%. 
Several factors predispose THA patients to pelvic discontinuities: [2,3]
- Prior pelvic radiation
- Female gender
- Diagnosis of rheumatoid arthritis
Pelvic discontinuities can be sub-classified into either acute or chronic, with chronic discontinuities thought of as non-unions. 
ICJR: What are the options for treating pelvic discontinuity in a revision procedure?
Scott M. Sporer, MD: Several options are available to treat this challenging problem when encountered in a revision THA. Most surgeons agree that acute discontinuities should be treated with stabilization of the fracture by means of internal fixation, consisting of plating and then using a jumbo cup with numerous screws to ensure adequate stability. 
Varying options have been proposed to treat chronic discontinuities:
- Acetabular cage
- Acetabular allograft with a cage and cemented liner
- Cup-cage constructs
- Custom triflange
- Tantalum acetabular cup and augment construct
- Acetabular distraction
ICJR: What outcomes can the surgeon expect with these treatment options?
Dr. Melnic: Outcomes have been mixed for the treatment of chronic pelvic discontinuities.
- Acetabular cages lack biologic fixation and have demonstrated unfavorable results (50% to 60% failure rates). [6-8]
- Acetabular allograft with a cage and cemented liner is intended to restore bone stock, and this combination has shown satisfactory results – 72% survival rate at minimum of 10 years.  Historically, it has been preferred for a younger patient population.
- Cup-cage constructs have offered promising results, with recent studies demonstrating survival rates from 85% at 10 years  to 100% at a minimum 5-year follow-up. 
- Custom triflange acetabular components have shown survivorship ranging from 65% at 5 years  to 100% at a mean of 10 years. 
- Tantalum acetabular cups and augment constructs have shown less promising results. At a minimum of 5 years, Jenkins et al  found that 55% of these constructs either failed or were as risk for future failure.
Dr. Sporer: Given these outcomes, we advocate for the acetabular distraction technique with a jumbo cup and porous metal augments, which was first popularized by Paprosky et al  to treat chronic pelvic discontinuities.
Peripheral distraction allows for medial compression, creating the biology needed to heal these non-unions. As previously demonstrated, acetabular distraction provides excellent results with respect to pain and functional scores, and only 1 out of 20 patients require re-revision for aseptic loosening. 
When tackling discontinuities, the treating surgeon must have a clear understanding of the type of discontinuity that is present and then formulate a detailed plan to solve this challenging problem.
- Abdel MP, Trousdale RT, Berry DJ. Pelvic Discontinuity Associated With Total Hip Arthroplasty: Evaluation and Management. The Journal of the American Academy of Orthopaedic Surgeons. 2017 May;25(5):330-8.
- Berry DJ. Identification and management of pelvic discontinuity. Orthopedics. 2001 Sep;24(9):881-2.
- Joglekar SB, Rose PS, Lewallen DG, Sim FH. Tantalum acetabular cups provide secure fixation in THA after pelvic irradiation at minimum 5-year followup. Clinical orthopaedics and related research. 2012 Nov;470(11):3041-7.
- Sheth NP, Melnic CM, Paprosky WG. Acetabular distraction: an alternative for severe acetabular bone loss and chronic pelvic discontinuity. The bone & joint journal. 2014 Nov;96-B(11 Supple A):36-42.
- Petrie J, Sassoon A, Haidukewych GJ. Pelvic discontinuity: current solutions. The bone & joint journal. 2013 Nov;95-B(11 Suppl A):109-13.
- Paprosky W, Sporer S, O’Rourke MR. The treatment of pelvic discontinuity with acetabular cages. Clinical orthopaedics and related research. 2006 Dec;453:183-7.
- Goodman S, Saastamoinen H, Shasha N, Gross A. Complications of ilioischial reconstruction rings in revision total hip arthroplasty. The Journal of arthroplasty. 2004 Jun;19(4):436-46.
- Gross AE, Goodman S. The current role of structural grafts and cages in revision arthroplasty of the hip. Clinical orthopaedics and related research. 2004 Dec(429):193-200.
- Regis D, Sandri A, Bonetti I, Bortolami O, Bartolozzi P. A minimum of 10-year follow-up of the Burch-Schneider cage and bulk allografts for the revision of pelvic discontinuity. The Journal of arthroplasty. 2012 Jun;27(6):1057-63 e1.
- Amenabar T, Rahman WA, Hetaimish BM, Kuzyk PR, Safir OA, Gross AE. Promising Mid-term Results With a Cup-cage Construct for Large Acetabular Defects and Pelvic Discontinuity. Clinical orthopaedics and related research. 2016 Feb;474(2):408-14.
- Martin JR, Barrett I, Sierra RJ, Lewallen DG, Berry DJ. Construct Rigidity: Keystone for Treating Pelvic Discontinuity. The Journal of bone and joint surgery American volume. 2017 May 03;99(9):e43.
- Taunton MJ, Fehring TK, Edwards P, Bernasek T, Holt GE, Christie MJ. Pelvic discontinuity treated with custom triflange component: a reliable option. Clinical orthopaedics and related research. 2012 Feb;470(2):428-34.
- DeBoer DK, Christie MJ, Brinson MF, Morrison JC. Revision total hip arthroplasty for pelvic discontinuity. The Journal of bone and joint surgery American volume. 2007 Apr;89(4):835-40.
- Jenkins DR, Odland AN, Sierra RJ, Hanssen AD, Lewallen DG. Minimum Five-Year Outcomes with Porous Tantalum Acetabular Cup and Augment Construct in Complex Revision Total Hip Arthroplasty. The Journal of bone and joint surgery American volume. 2017 May 17;99(10):e49.
- Sporer SM, Bottros JJ, Hulst JB, Kancherla VK, Moric M, Paprosky WG. Acetabular distraction: an alternative for severe defects with chronic pelvic discontinuity? Clinical orthopaedics and related research. 2012 Nov;470(11):3156-63.
About the Experts
Christopher M. Melnic, MD, is from Massachusetts General Hospital and Harvard Medical School, where he is an instructor of orthopaedic surgery in the Department of Orthopaedic Surgery. Scott M. Sporer, MD, is from Central Dupage Hospital – Northwestern University and Rush University, where he is an associate professor of orthopaedic surgery in the Department of Orthopaedic Surgery.
Dr. Melnic and Dr. Sporer have no disclosures relevant to this article.