Importance of Post-Reduction CT Scans in Posterior and Transverse Posterior Wall Acetabular Fracture-Dislocations.

Objectives: To report the frequency of patients with pre- and post-reduction computed tomography (CT) scans associated with acetabular fracture-dislocations and the change of associated intra-articular fragments occurring with joint reduction.

Methods: Design: Retrospective case series.

Setting: Regional Level 1 trauma center.

Patient selection criteria: Patients who sustained an OTA/AO 62A1 and 62B1 posterior wall or transverse posterior wall acetabular fracture-dislocations with pre- and post-reduction CT imaging from February 2020 until July 2023.

Outcome measures and comparisons: Intra-articular fragments were identified and change in position (fossa to cranial, intra-articular to extra-articular, etc.) noted from pre- to post-reduction scans. Operative reports and post-operative CT scans were reviewed to determine the frequency of fragment retrieval.

Results: 119 out of 394 (30.2%) patients meeting fracture pattern inclusion received a CT scan prior to hip reduction. Of the 394 patients, 100 (25.9%) had pre- and post-reduction CT scans and were studied (average age of 35.5 years (range 16 - 87 years), 59 male). 45 of 100 patients (45%) had pre-reduction CT imaging demonstrating the presence of intra-articular fragment(s). 30 of 45 patients with a pre-reduction intra-articular fragment (66.7%) had an intra-articular fragment location change during the reduction. Of the 55 patients who did not have an intra-articular fragment on pre-reduction imaging, 28 of 55 (50.9%) had at least 1 intra-articular fragment on the post-reduction CT. Complete fragment retrieval was performed in 71.4% of patients.

Conclusions: The study demonstrated 30.2% of patients with posterior wall and transverse posterior wall acetabular fracture-dislocations received a CT scan prior to hip reduction. It was common to find intra-articular fragments on the post-reduction CT in patients who did not have them on the pre-reduction CT. Obtaining and scrutinizing the post-reduction CT scan provided accurate knowledge of the location of all osseous fragments associated with the fracture-dislocations which facilitated thorough preoperative planning, intraoperative implementation, and hopeful long-term patient outcomes.

Level of evidence: Prognostic Level IV.