A novel anatomically pre-contoured side-specific titanium plate versus the reconstruction plate for quadrilateral plate fractures of the acetabulum: a propensity-matched cohort study

Biomechanical simulation of bed turning post-acetabular fracture fixation

Before patients begin out-of-bed exercises following internal fixation surgery for acetabular fractures, turning over in bed serves as a crucial intervention to mitigate complications associated with prolonged bed rest. However, data on the safety of this maneuver post-surgery are limited, and the biomechanical evidence remains unclear. This study aims to introduce a novel loading protocol designed to preliminarily simulate the action of turning over in bed and to compare the biomechanical properties of two fixation methods for acetabular fractures under this new protocol. A RNJ-500 microcomputer-controlled electronic torsion tester was utilized to simulate the action of turning over in bed and to conduct a dynamic torsion loading test. Initially, the torque values and torsional stiffness of six intact pelvis specimens (Group A) were measured. A double-column acetabular fracture model was then created and stabilized using two different fixation methods: the Dynamic Anterior Plate-Screw System for the Quadrilateral plate (DAPSQ, Group B) and the traditional anterior reconstruction titanium plate plus a 1/3 tubular buttress plate (Group C). All specimens underwent cyclic torsion loading ranging from 2° to 8°. The medial displacement and strain values of the quadrilateral plate were recorded and analyzed. As the torsion angles increased from 2° to 8°, Groups A and B exhibited significantly higher torque values compared to Group C (all P < 0.05). Group C demonstrated notably lower torsional stiffness (1.51 ± 0.20) relative to Group A (2.33 ± 0.25, P < 0.05) and Group B (2.21 ± 0.29, P < 0.05). Additionally, the medial displacement of the quadrilateral plate was significantly reduced in Group B compared to Group C at all measured time points (P < 0.05). And Group C exhibited significantly higher maximum tensile and compressive strain than Group B (all P < 0.05). The DAPSQ plate with quadrilateral screws provides superior anti-rotational stability in a double-column acetabular fracture model under the newly established torsion loading protocol.

Quadrilateral plate fractures

During the last two decades, extended scientific interest focused on quadrilateral plate (QLP) fractures as part of common acetabular fractures. The QLP corresponds to the medial wall of the acetabulum, and different fracture pattern of Letournel´s fracture types are associated with concomitant QLP fractures. Except anterior and posterior wall fractures, all other fracture types may be associated with QLP fractures. QLP fracture features include simple fracture lines up to highly comminuted fractures. A detailed preoperative analysis of these fractures is important to get a better understanding of intraoperative decision making. No consensus exists regarding the optimal classification and treatment of QLP fractures. Various operative approaches and treatment concepts exists depending on the specific QLP fracture type and the acetabular fracture type. Several new implants were development for optimal but often individual stabilization concepts. The gold-standard is still some medial buttressing during internal fixation predominantly using plates, but also screw fixation is considered an option. Additional dome impactions must be considered as an integral part in any QLP fracture analysis and stabilization.

Inclined angles of acetabular quadrilateral plate: digital measurement and clinical application of the new anatomical concept

PURPOSE

Matta scoring standard is one of the most frequently used postoperative imaging evaluations for acetabular fracture reduction, but has obvious shortcomings. This study, for the first time, proposed the concept of inclined angles of acetabular quadrilateral plate. The purpose of this study was to investigate the normal range of the inclined angles in adults by digital measurement and explore the feasibility of using them to evaluate the reduction quality of acetabular quadrilateral fractures after surgery.

METHODS

Firstly, the pelvic CT three-dimensional reconstruction data of 40 healthy adults including 20 males and 20 females were collected. The normal range of the anterior, middle, and posterior inclined angles were measured via Mimics software. Secondly, a modified Matta criteria that combined the classic Matta criteria and evaluation criteria of the inclined angles was proposed. And we classified modified Matta criteria into three grades including excellent, good and poor. Finally, a total of 125 cases with quadrilateral plate fractures was included and the postoperative CT data were analyzed by using both the classic Matta criteria and our modified Matta criteria. Then, the accuracy and consistency of both criteria to evaluate postoperative hip function was investigated.

RESULTS

The average anterior inclined angle: male (97.11° ± 2.59°), female (90.63° ± 2.09°); middle inclined angle: male (105.57° ± 1.93°), female (100.64° ± 2.46°); and posterior inclined angle: male (112.62° ± 2.54), female (106.37° ± 2.53°). Whether in males or in females, the anterior, middle, and posterior inclined angles showed a progressively increasing trend. All the three inclined angles in males were all significantly larger than those in females (p < 0.05). Among 125 cases with quadrilateral plate fractures, 101 cases (80.8%) were graded as excellent, 18 cases (14.4%) as good, and 6 cases (4.8%) as poor according to the classic Matta criteria. While based on modified Matta criteria, there were excellent in 37 cases (29.6%), good in 76 cases (60.8%), and poor in 12 cases (9.6%). According to the Harris hip score system, the functional outcomes were excellent in 59 cases (47.2%), good in 26 cases (20.8%), fair in 24 cases (19.2%), and poor in 16 cases (12.8%). Our results showed that among the cases evaluated as excellent according to the classic Matta criteria and modified Matta criteria, the excellent-to-good rates of hip function were 70.3% and 78.4%, respectively. And among the cases evaluated as poor according to the modified Matta criteria, the fair-to-poor rate of hip function was 75%, while this value was 50% for classic Matta criteria. Both differences were statistically significant (p < 0.05).

CONCLUSION

Inclined angles of the quadrilateral plate could be used to assess the quality of fracture reduction and provide a basis for evaluating the rotational displacement of fracture blocks in the quadrilateral plate, which compensates the shortage of classic Matta criteria.

A systematic review of follow-up results of additively manufactured customized implants for the pelvic area

INTRODUCTION

While 3D printing of bone models for preoperative planning or customized surgical templating has been successfully implemented, the use of patient-specific additively manufactured (AM) implants is a newer application not yet well established. To fully evaluate the advantages and shortcomings of such implants, their follow-up results need to be evaluated.

AREA COVERED

This systematic review provides a survey of the reported follow-ups on AM implants used for oncologic reconstruction, total hip arthroplasty both primary and revision, acetabular fracture, and sacrum defects.

EXPERT OPINION

The review shows that Titanium alloy (Ti4AL6V) is the most common type of material system used due to its excellent biomechanical properties. Electron beam melting (EBM) is the predominant AM process for manufacturing implants. In almost all cases, porosity at the contact surface is implemented through the design of lattice or porous structures to enhance osseointegration. The follow-up evaluations show promising results, with only a small number of patients suffering from aseptic loosening, wear, or malalignment. The longest reported follow-up length was 120 months for acetabular cages and 96 months for acetabular cups. The AM implants have proven to serve as an excellent option to restore premorbid skeletal anatomy of the pelvis.

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

AIMS

With relatively thinner cortical thickness, the management of acetabulum osteoporotic fractures in elderly patients is difficult. The aim of the research was to compare and present the morphological characteristics of the quadrilateral plate in young and elderly age groups, such as the area, and position distribution of the thin cortical thickness region, fracture lines maps, and propose a revised design plate for elderly patients based on these anatomic information.

METHODS

As a retrospective research, acetabular fracture with one normal hemipelvises, including 110 men and 39 women, were collected to present the morphological characteristics of the quadrilateral region. The subjects were divided into three different age groups: Group I = 18-40 years (31.3 ± 6.6 years), Group II = 41-60 years (49.9 ± 5.3 years), and Group III ≥ 61 years (68.7 ± 6.8 years). The area of the quadrilateral surface, the area and position distribution of the thin cortical thickness region, the ratio and fracture lines maps were calculated and compared with Mimics in different groups.

RESULTS

The thin cortical thickness/width region area (TCWRA) was significantly increased in Group III compared with Group I and Group II. The ratio of TCWRA accounted for in the quadrilateral region was also significantly increased in Group III (≥ 61 years) compared with Group I (P = 0.01) and Group II (P = 0.011). None of the subjects had a component involving the "A" zone, thirty-three thin cortical thickness regions were located in the "B" zone, and one hundred and sixteen involved both zones of the quadrilateral plate ("A + B" zone). Furthermore, there were a significant differences in the fracture line distributions in three age groups. More fracture lines of elderly patients were located at anterior part (B zone) compared with Group I and Group II.

CONCLUSIONS

It was identified the area of thin cortical thickness region increased as age grown, and fracture lines were inclined to be more distributed in "B" zone in elderly patients. To meet the demands of acetabular fixation in different age groups, cortical thickness changes in young and elderly individuals should be given special attention when the quadrilateral surface plate is designed. Level of evidence Level IV, observational study.

Quadrilateral plate fractures of the acetabulum: Classification, approach, implant therapy and related research progress

The quadrilateral plate (QP) is an essential structure of the inner wall of the acetabulum, an important weight-bearing joint of the human body, which is often involved in acetabular fractures. The operative exposure, reduction and fixation of QP fractures have always been the difficulties in orthopedics due to the special morphological structure and anatomical features of the QP. Fortunately, there have been many effective methods and instruments developed for QP exposure, reduction and fixation by virtue of the combined efforts of numerous orthopedists. At the same time, each method presents with its own advantages and disadvantages, resulting in different prognoses. It is necessary to have a thorough understanding of the anatomy, radiology and fixation techniques of the QP in terms of patient prognosis optimization. In this paper, the anatomical features, definition and classification of QP, operative approach selection, implant internal fixation methods and efficacy were reviewed.

Double column acetabular fractures fixation using a novel dynamic anterior plate-screw system: A biomechanical analysis

BACKGROUND

According to the classification of Judet and Letournel, all double column acetabular fractures will certainly involve the disruption of the quadrilateral plate (QLP). Accurate reduction and reliable fixation of QLP is the key to obtain a normal congruent hip joint and avoid postoperative arthritis. The aims of this study were to assess the biomechanical properties of a novel dynamic anterior plate-screw system (named DAPSQ) and to compare its biomechanical stability with buttress-plate construct.

METHODS

Double column acetabular fractures involving the QLP were created on cadaveric pelvic specimens and subsequently stabilized with (1) a pre-contoured side-specific DAPSQ titanium plate and 4 quadrilateral screws (Group A) or a 12-hole suprapectineal pelvic reconstruction plate combined with a 9-hole 1/3 tube buttress plate (Group B). These constructs were mechanically loaded on ZwickZ 100 testing machine. Construct stiffness and displacement amounts of the two fixation methods in the condition of dynamic axial loading conditions were measured.

RESULTS

As the axial loading force increased from 200 N to 800 N, the longitudinal displacement of each pelvic specimen increased linearly and Group B was found to have significantly higher displacement than Group A (p<0.05). In the 600 N physiological loading, the construct stiffness values of Groups A and B were 139.4 ± 37.4 N/mm and 101±18.3 N/mm, respectively. Group A is 27% stiffer than Group B(p<0.05).

CONCLUSIONS

In this in vitro biomechanical study, DAPSQ plate and quadrilateral screws fixation of a double column acetabular fracture involving the QLP resulted in a better fixation construct than the traditional suprapectineal pelvic reconstruction plate and 1/3 tube buttress plate fixation.

Open reduction and internal fixation of quadrilateral plate fractures in the elderly: association between initial fracture pattern and outcomes

Background

Acetabular fractures with medial displacement of the quadrilateral plate (QLP) are common in the elderly. The presence of QLP fractures greatly increase the surgical difficulty of acetabular fractures. This study aims to evaluate the clinical radiological outcomes of open reduction and internal fixation (ORIF) in QLP fractures in elderly patients and to investigate factors potentially affecting the result.

Methods

We conducted a retrospective study. A series of 37 consecutive patients with acetabular fracture involving the QLP aged 60 years and older who received ORIF between January 2010 and May 2019 were included. QLP fractures were classified according to Walid’s classification system. Radiological outcomes were evaluated using Matta criteria and functional outcomes were assessed using the modified Merle d’Aubigné score. The relationships between Walid’s classification and radiological or functional outcomes were analyzed.

Results

According to Walid’s classification, 18, 13, 6 were classified as QLP1, QLP2 and QLP3, respectively. The average follow-up was 35.5 ± 10.7 months. We obtained anatomic reduction in 48.6 % (18/37) of cases, imperfect reduction in 40.5 % (15/37) of cases, and poor reduction in 10.8 % (4/37) of cases. Excellent-good functional scores were found in 83.7 % (modified Merle d’Aubigné). There were no cases of screw entering the hip, pull-out and loosening or implant failure during the follow-up. Walid’s classification was positively correlated with radiological outcomes of reduction (r = 0.661; P < 0.001), and functional outcomes (r = 0.478; P = 0.003). Unsatisfactory reduction was demonstrated a correlation with the development of post-traumatic arthritis (r =-0.410; P = 0.012).

Conclusions

ORIF may be suggested for quadrilateral plate fractures in the elderly. Walid’s classification system is associated with the reduction quality and functional recovery.