Third-Generation Dynamic Anterior Plate-Screw System for Quadrilateral Fractures: Digital Design Based on 834 Pelvic Measurements.

Background and Objectives: To investigate the digital measurement method for the plate trajectory of dynamic anterior plate-screw system for quadrilateral plate (DAPSQ), and then design a third-generation DAPSQ plate that conforms to the needs of the Chinese population through collating a large sample anatomical data. Materials and Methods: Firstly, the length of the pubic region, quadrilateral region, iliac region, and the total length of the DAPSQ trajectory were measured by a digital measurement approach in 22 complete pelvic specimens. Then, the results were compared with the direct measurement of pelvic specimens to verify the reliability of the digital measurement method. Secondly, 504 cases (834 hemilateral pelvis) of adult pelvic CT images were collected from four medical centers in China. The four DAPSQ trajectory parameters were obtained with the digital measurement method. Finally, the third-generation DAPSQ plate was designed, and its applicability was verified. Results: There was no statistically significant difference in the four trajectory parameters when comparing the direct measurement method with the digital measurement method (p > 0.05). The average lengths of the pubic region, quadrilateral region, iliac region, and the total length in Chinese population were (60.96 ± 5.39) mm, (69.11 ± 5.28) mm, (84.40 ± 6.41) mm, and (214.46 ± 10.15) mm, respectively. Based on the measurement results, six models of the DAPSQ plate including small size (A1,A2), medium size (B1,B2), and the large size (C1,C2) were designed. The verification experiment showed that all these six type plates could meet the requirement of 94.36% cases. Conclusions: A reliable computerized method for measuring irregular pelvic structure was proposed, which not only provided an anatomical basis for the design of the third-generation DAPSQ plate, but also provided a reference for the design of other pelvic fixation devices.

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.

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.

Personalized Three-Dimensional Printed Anterior Titanium Plate to Treat Double-Column Acetabular Fractures: A Retrospective Case-Control Study.

OBJECTIVE: To compare the clinical efficacy and safety of a personalized three-dimensional (3D) printed dynamic anterior plate-screw system for the quadrilateral area (DAPSQ) titanium plate and a traditional DAPSQ reconstruction plate in the treatment of double-column acetabular fractures. METHODS: This was a retrospective case-control study. From May 2014 to January 2018, 43 patients with double-column acetabular fractures underwent open reduction and internal fixation. Among these, 20 cases were fixed with a 3D printed DAPSQ plate (3D printed group) and 23 cases were fixed with a DAPSQ reconstruction plate (control group). The 3D printed group comprised 15 men and 5 women, with an average age of 50.1 ± 8.2 years. The control group comprised 16 men and 7 women, with an average age of 51.0 ± 8.6 years. The evaluation index included the surgical data (i.e. blood loss, operating time, duration of hospital stay, and intraoperative and postoperative complications), position and length of implants, reduction quality, hip function, and related complications. The reduction quality was evaluated using the Matta scoring standard and hip function was evaluated using the modified Merle d'Aubigné score. RESULTS: A total of 43 patients met the inclusion criteria. The mean postoperative follow up was 35.2 months in the 3D printed group and 36.9 months in the control group. There were no significant group differences in demographic data between the two groups. The position and length of the 3D printed implants were generally in accord with preoperative planning using a 3D pelvic model. Patients in the 3D printed group had significantly shorter operation time (223.2 vs 260.5 min, P < 0.05) and less intraoperative blood loss (930.4 vs 1426.1 mL, P < 0.05) compared to the control group. Anatomic, imperfect, and poor reduction was obtained in 13, 5, and 2 cases in the 3D printed group, respectively, and was obtained in 12, 8, and 3 cases in the control group. The modified Merle d'Aubigné scores were excellent in 11 cases, good in seven cases, and fair in two cases in the 3D printed group. They were excellent in 11 cases, good in eight cases, fair in three cases, and poor in one case in the control group. The reduction quality and hip function did not differ within the groups (P > 0.05). The general complication rate in the 3D printed group and the control group was 15% and 26.1%, respectively, but the difference between the two groups was not statistically significant. CONCLUSION: Use of a personalized 3D printed DAPSQ plate has potential advantages in reducing the operation time and blood loss during the treatment of double-column acetabular fractures.