Fixation of Transverse Acetabular Fractures With Precontoured Plates Alone Causes Fracture Malreduction: A Biomechanical Assessment

Abstract

Background: Precontoured quadrilateral surface buttress (PQSB) plates have grown in popularity for acetabular fracture fixation. However, our experience has pushed us to hypothesize that their use as sole means of fixation may cause fracture malreduction. A biomechanical model was created to investigate this theory. Methods: A transverse acetabular fracture was created and reduced anatomically in 18 synthetic hemipelvises. The reduced hemipelvises were fixated using 3 different techniques. Group A fixation included anterior and posterior column screws plus a suprapectineal pelvic reconstruction plate; group B models were fixed using a PQSB plate only; and group C models were fixed with an anterior column screw and a PQSB plate. Acetabular tracking points were placed before final fixation and used to quantify any postfixation displacement. One-way analysis of variance and Tukey HSD testing were used to determine the significant difference (P < 0.05). Results: Models in group B had significant fracture displacement after final fixation when compared with group A and group C models. The average amount of displacement at the anterior column and within the acetabulum was 1.37 mm (95% CI, 1.08–1.65) in group B constructs compared with 0.32 mm (95% CI, 0.22–0.42) and 0.26 mm (95% CI, 0.15–0.38) in groups A and C constructs, respectively. There were no significant differences in displacement after final fixation between group A and group C models. Conclusions: PQSB plates for acetabular fractures cause malreduction when applied in isolation in this biomechanical model. If a PQSB plate is chosen for fixation, we suggest the use of a columnar lag screw at minimum to hold reduction before plate application.

Differences in fixation to young and elderly quadrilateral surfaces with anatomic quadrilateral surface plate (AQSP) based on cortical thickness morphological results

“…Among many methods to fix the quadrilateral region, an increasingly popular one is the anterior intrapelvic approach, which allows access to the anterior column and medial surface of the posterior column for buttress plate fixation of both columns and offers the benefit of less surgical exposure [ 3 ]. However, standard implants such as constructed plates may not be able to obtain satisfactory fixation for displaced quadrilateral regions, so newer preshaped fixation plates have been proposed, with some of these already in use [ 4 ]. We also reported that satisfactory fixation can be obtained by using an ‘anatomic quadrilateral surface plate (AQSP) [ 5 ].…”

Surgical Drill Guide for Insertion of an Infra-Acetabular Screw Based on an Anatomically Precontoured Plate System: A Cadaveric Study

“…Since there is no previous data, this preliminary study was designed as an exploratory pilot study without any a priori sample size calculation based on a primary endpoint. Based on the low variance of values in the previous radiomorphometric study and based on other experimental studies, a sample size of 12 specimens was considered feasible and expected to have enough power [ 16 , 19 ]. Unless otherwise stated, descriptive data are given as mean ± standard deviation.…”

Biomechanical evaluation of a healed acetabulum with internal fixators: finite element analysis

“…Cai et al [ 7 ], Fan et al [ 8 ] and Marmor et al [ 9 ] adopt cadaveric bone for biomechanical testing, which leads to difficulty in obtaining experimental samples. Krappinger et al [ 10 , 11 ], Alfonso et al [ 12 ] and Wu et al [ 13 ] choose synthetic pelvis models, which leads to high cost. Additionally, there is no existing standardized mechanical experimental method [ 1 , 6 ].…”