Total Hip Arthroplasty in Patients With Severe Chronic Pubic Diastasis

Abstract

Background: Total hip arthroplasty (THA) in patients with severe chronic pubic diastasis from either congenital or acquired causes presents an exceptionally difficult challenge that has rarely been addressed in the arthroplasty literature. The purpose of this paper is to present a series of THAs in patients with severe chronic pubic diastasis, asking the following research questions: (1) What is the survivorship and clinical outcomes after THA in patients with severe chronic pubic diastasis? And (2) What is the rate of complications after THA surgery in this challenging patient population? We additionally describe our algorithm for preoperative planning and rationale for surgical technique and implant position.

Material and methods: We retrospectively queried the prospective arthroplasty database of 2 high-volume referral centers, yielding 6 THA in 4 patients with severe chronic pubic diastasis (minimum 8 cm) with a mean follow-up of 2.7 years. We recorded baseline demographic and intraoperative variables, as well as survivorship, patient-reported outcomes (Hip disability and Osteoarthritis Outcome Score for Joint Replacement score), and incidence of complications.

Results: There were no failures reported (100% survivorship) at a mean follow-up of 2.7 years. Mean Hip disability and Osteoarthritis Outcome Score for Joint Replacement scores improved from 36.0 preoperatively to 82.8 postoperatively. There were no infections, dislocations, fractures, or any major complications in the postoperative period.

Conclusion: THA for patients with severe chronic pubic diastasis remains a rare but challenging reconstructive procedure. Excellent outcomes can be achieved with adequate preparation, particularly regarding the acetabular component position. Understanding the nature of the hemipelvis deformity and meticulous templating using "normalized" views of the hip are important components to a successful preoperative plan.

Keywords: Patient-reported outcomes; Pre-operative planning; Pubic diastasis; Survivorship; Total hip arthroplasty.

Figure 1

Patient with chronic post-traumatic pubic diastasis. The deformity of the hemipelvis positions the acetabulum in an excessively vertical and retroverted position. The red arrow demonstrates the excess anterior wall osteophyte.

Figure 2

For preoperative planning, a standing anteroposterior radiograph is taken with the patient’s pelvis internally rotated 20°-30° to obtain a “normalized” view of the hemipelvis, with more normal-appearing morphology of the obturator foramen (asterisk).

Figure 3

Intraoperatively, the “normalized” view of the standing hemipelvis is re-created using fluoroscopy to navigate the cup position. Note the more normal-appearing morphology of the obturator foramen. In this case, the cup position was reamed under fluoroscopy and lateralized several millimeters to maintain the patient’s native hip offset. Asterisk (∗) denotes the position of the obturator foramen.

Figure 4

The cup appearance on postoperative anteroposterior pelvis film may appear neutral or even slightly retroverted due to the external rotation deformity of the hemipelvis. Note the slightly lateralized position of the right acetabular component to reconstruct the patient’s high offset. A line between the 2 separated ends of the pubic symphysis demonstrates a pubic diastasis of 108 mm.

Figure 5

The “normalized” view of the hip (a) is obtained by internally rotating the patient 20-30° to offset the external rotation deformity of the hemipelvis. Note the difference in morphology of the obturator foramen compared with the standard AP view (b). Asterisk (∗) denotes the position of the obturator foramen.