Endopelvic zones and constant fragment mapping in acetabular fractures

This study aims to characterize the constant fragment (CF) in acetabular fractures and to provide a novel nomenclature of anatomic zones from the vantage point of the endopelvic approach.

Retrospective clinical study SETTING: Urban Level I trauma center, Patients/participants: One hundred and eleven consecutive acetabular fractures eligible for an AIP approach and treated surgically.

3D mapping of the CF line of fractures using a novel endopelvic anatomical zoning system.

Correlation of Letournel's fracture types to the size of the CF and its location based on precise anatomical nomenclature.

The average age of patients was 47 years (range, 12 to 88 years), predominantly comprising male patients (78 %, n = 87) and female patients (22 %, n = 24). Fractures were grouped into 3 categories based on the size of the CF and its location from anterior to posterior. Group 1 included AC fractures which demonstrated the largest CF. The CF nearly always spared Zone 4. Group 2 included transverse fractures, T-Type fractures, and T-Type with posterior wall fractures. The CF was of intermediate size, and it often spared Zone 4. Group 3 included anterior column posterior hemitransverse fractures and associated both column fractures. The CF was the smallest of all categories and rarely spared Zone 4.

Our analysis suggests consistent and repeatable patterns and sizes of constant fragments. These findings can serve as an endopelvic roadmap for the AIP approach based on fracture types, guiding placement of reduction clamps, vectors of reduction and hardware position.