Comparative study of the 3D morphological differences in associated both-column acetabular fractures between elderly and young adults

Abstract

Introduction: The occurrence of associated both-column acetabular fractures (ABC-AFs) is common in the elderly, yet their morphological characteristics compared to younger adults remain unclear.

Materials and methods: This retrospective study analyzed 123 cases of ABC-AFs: elderly patients (≥ 65 years, n = 47, group A) and younger adults (< 65 years, n = 76, group B). Using Mimics and 3-matic, fracture line (FL) distributions in the anterior column (AC), quadrilateral plate (QP), and posterior wall (PW) fragments were examined. Comparisons focused on the articular surface, ilium, QP area, and retro-acetabular surface (RAS). Harris hip scores (HHS) were recorded and compared one-year post-surgery.

Results: The distribution of FLs of the AC fragment on the anteroinferior wall, acetabulum, inner and outer sides of the ilium was similar between groups A and B except that group A had sparser FL distribution on the posterosuperior rim and fewer FLs extending into the sacroiliac joint. A comparable pattern of FLs of the QP fragments on the QP area and the RAS was also confirmed. On the RAS, group A exhibited fewer cranial transverse lines (8.5% vs. 25.0%) and more inverse lines (44.7% vs. 23.7%) than group B (p = 0.011). A higher incidence of PW fragments was identified in group A (72.3% vs. 53.9%, p = 0.042). The number of intra-articular fragments was higher in group A than group B (3.8 vs. 3.4, p = 0.031), but the composition of the articular surface was similar. The average HHS was 77.6 in group A and 83.0 in group B (p = 0.007), with excellent/good ratios of 59.5% and 74.7% (p < 0.001), respectively.

Conclusions: The similar morphological patterns of ABC-AFs and favorable functional outcomes suggest that surgical principles for younger patients could be applicable to elderly patients, with careful considerations for osteoporosis and co-morbidities.

Keywords: Anterior column; Associated both-column acetabular fractures; Fracture lines; Fracture mapping; Posterior column; Posterior wall; Quadrilateral plate.