Dynamic Anterior Plate-screw System Research Articles

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.

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

BackgroundAccording 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. MethodsDouble 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. ResultsAs 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). ConclusionsIn 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.

ObjectiveTo 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.MethodsThis 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.ResultsA 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.ConclusionUse 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.

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

BackgroundSurgical treatment of acetabular fractures involving a quadrilateral plate is a challenge to orthopedic surgeons. We have developed a novel fixation technique using a specially shaped reconstruction plate combined with several buttress screws of a quadrilateral plate which was also called a dynamic anterior plate-screw system for quadrilateral plate (DAPSQ) to treat acetabular fractures involving quadrilateral plate since 2005 (RP group). And the long-term follow-up results have confirmed the effectiveness and safety of this technique. After 2016, standardized titanium plate (STP group) of DAPSQ have been designed and applied. The aim of the study was to compare the clinical efficacy of anatomical plate and the reconstruction plate of DAPSQ in the treatment of quadrilateral plate fractures.MethodsWe led a propensity-matched cohort study of quadrilateral plate fractures. Twenty-two patients were included in the STP group during the inclusion period (2016–2018) and were matched to 22 cases in our database of the RP group (2008–2016). The primary outcome measures were the quality of reduction and functional outcomes. Intraoperative conditions were also compared.ResultsOf these 22 consecutive patients in the STP group, the mean age was 46.7 years and the most common fracture pattern was a both-column fracture (12 cases, 54.5%) according to Letournel-Judet classification. The mean follow-up period was 23.1 months (range 12–37). There were no significant differences between the two groups with regard to the quality of reduction using the Matta radiological criteria and functional outcomes evaluated by the modified Merle d’Aubigné score (P > 0.05). Compared with the RP group, the STP group had a shorter operation time (245.1 min vs. 286.8 min, P = 0.020), less intraoperative blood loss (1136.4 mL vs. 1777.3 mL, P = 0.014), and transfusion (780.9 vs. 1256.8 mL, P = 0.035). The complication rate was 18.2% in the STP group, and there was no significant difference compared with the RP group (36.4%) (P > 0.05). None of the cases in the two groups had quadrilateral screws entering the hip or implant failure.ConclusionsThe fixation of standardized titanium plate in quadrilateral plate fractures showed a similar result to the reconstruction plate, in terms of quality of reduction and functional outcome. The standardized titanium plate of DAPSQ has the advantages of a short operation time, less intraoperative bleeding, and blood transfusion, and it is worth further promotion and research.

Single Ilioinguinal Approach to Treat Complex Acetabular Fractures with Quadrilateral Plate Involvement: Outcomes Using a Novel Dynamic Anterior Plate-Screw System.

ObjectivesTo evaluate the efficacy and safety of a novel fixation technique referred to as the dynamic anterior plate–screw system for quadrilateral plate (DAPSQ) for complex acetabular fractures with quadrilateral plate involvement through the single ilioinguinal approach.MethodsA total of 32 patients with acetabular fractures, selected between January 2009 and March 2016, were managed by DAPSQ with “quadrilateral screws” through single ilioinguinal approach. The primary outcomes measure was the reduction quality evaluated according to the Matta radiological criteria, and the functional outcomes were evaluated by the modified Merle d'Aubigné score at the last follow‐up. Secondary outcomes were postoperative complications and intraoperative conditions included, for instance, operation time and blood loss.ResultsOf these 32 consecutive patients, 19, 9, and 4 were classified as both columns, anterior column posterior hemi‐transverse, and T‐shaped fractures, respectively, and with an average of 47 months’ follow‐up. Anatomic reduction was obtained in 19 cases (59%), imperfect reduction in 9 cases (28%), and poor reduction in 4 cases (13%). The modified Merle d'Aubigné scores were excellent in 15 cases (47%), good in 13 cases (41%), fair in 2 cases (6%), and poor in 2 cases (6%). Three cases sustained temporary lateral femoral cutaneous nerve injuries. One patient had a superficial wound infection that resolved after debridement. Five patients had posttraumatic arthritis; one of them underwent total hip arthroplasty at 46 months. No cases had quadrilateral screws entering the hip joint.ConclusionThe use of DAPSQ with quadrilateral screws is an effective and safe choice for complex acetabular fractures with quadrilateral plate involvement through the single ilioinguinal approach.

Application of dynamic anterior titanium plate-screw system assisted by preoperative digital design in treatment of acetabular bi-column fractures

Objective To investigate the clinical efficacy of dynamic anterior plate-screw system (DAPSQ) assisted by preoperative digital design in the treatment of acetabular bi-column fractures. Methods A retrospective case-control study was conducted to analyze the clinical data of 34 patients with acetabular bi-column fractures admitted to the General Hospital of Central Theater Command from January 2012 to January 2018. There were 24 males and 10 females, aged 21-65 years[(43.0±14.2)years]. According to the treatment method, the patients were divided into Group A treated with DAPSQ assisted by preoperative digital design and Group B treated with conventional DAPSQ.Group A was consisted of 17 patients, including 11 males and six females aged 22-64 years [(42.7±12.4)years]. Group B consisted of 17 patients, including 13 males and four females aged 21-65 years[(43.2±14.6)years]. The operation time, intraoperative blood loss, hospitalization time, fracture healing time, Matta radiological standard score of fracture reduction, Merle d'Aubignre-Postel score and complications were recorded and compared between the two groups. Results All patients were followed up for 12-62 months [(32.8±9.1)months]. The operation time [(160.8±38.5)minutes] and intraoperative bleeding [(455.6±190.4)ml] in Group A were significantly less than those in Group B [(216.9±59.5)minutes] and [(780.2±211.6)ml] (P 0.05). In Group A, four patients had traumatic arthritis, with one patient receiving total hip replacement. In Group B, three patients were found with traumatic arthritis, and one with avascular necrosis of femoral head who underwent total hip replacement. None of the two groups had complications such as screws' entry into articular cavity, failure of internal fixation, and incision infection. Conclusions For acetabular bi-column fractures, DAPSQ can effectively maintain the stability of the fracture, without the risk of screws entering the joint cavity, and obtain satisfactory clinical effect. Compared with conventional DAPSQ, preoperative digital design can significantly shorten the operation time and reduce intraoperative bleeding. Key words: Acetabulum; Imaging, three-dimensional; Surgery, computer-assisted; Fracture fixation, internal

Treatment of complex quadrilateral surface fractures of the acetabulum by internal fixation with dynamic anterior plate-screw system

Objective To explore the clinical efficacy of internal fixation with dynamic anterior plate-screw system for quadrilateral area(DAPSQ) in the treatment of complex acetabular fractures involving the quadrilateral surface. Methods Between January 2005 and January 2017, a series of 143 patients with complex quadrilateral surface fracture of the acetabulum were treated at Department of Orthopaedics, General Hospital of Central Theater Command. They were 86 males 57 females, with a mean age 46.6 years (range, from 19 to 77 years). By the Letournel-Judet classification, there were 38 anterior column plus posterior hemitransverse fractures, 26 T-shaped fractures and 79 double column fractures. They were all closed. The delay from injury to surgery averaged 9.6 days(range, from 3 to 21 days). All the cases were treated with DAPSQ internal fixation via the ilioinguinal approach. Their operation time, intraoperative bleeding volume, quality of fracture reduction, hip function and complications were recorded. Results The operation time for this series ranged from 2.5 to 5.0 hours, averaging 3.8 hours. The intraoperative blood bleeding ranged from 400 to 2,500 mL, with an average of 680 mL. By the Matta criteria for fracture reduction, 76 cases were rated as excellent, 51 as good and 16 as poor, giving an excellent and good rate of 88.8%. The 143 patients were followed up from 4 months to 10 years (mean, 4.1 years). The clinical fracture union was achieved after 2 to 4 months (mean, 3 months). By the modified Merle d’Aubigne & Postel criteria, the affected hips scored 9 to 18 points (mean, 16.3 points) at the final follow-ups, with 64 excellent, 52 good, 19 fair and 8 poor cases, giving an excellent and good rate of 81.1%. The postoperative complications included lesion of lateral femoral cutaneous nerve in 7 cases, urinary tract infection in 15 ones, traumatic osteoarthritis in 20 ones 5 of whom had to receive total hip arthroplasty, and heterotopic ossification (Brooker Grade Ⅰ) in 5 ones. Conclusion Internal fixation with DAPSQ is safe and effective for the treatment of complex acetabular fractures involving the quadrilateral surface. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Bone plates; Bone nails

Treatment of elderly patients with acetabular fracture involving medial displacement of the quadri-lateral surface using internal fixation with dynamic anterior plate-screw system for quadrilateral area

Objective To investigate the clinical efficacy of open reduction and internal fixation with dynamic anterior plate-screw system for quadrilateral area (DAPSQ) in the treatment of elderly patients with acetabular fracture involving medial displacement of the quadrilateral surface. Methods Between January 2007 and December 2014, a series of 18 senile patients with acetabular fractures involving medial displace-ment of the quadrilateral surface were treated at our department. They were 13 men 5 women, with a mean age 67.8 years (range, from 61 to 78 years). By the Judet-Letournel classification, there were 4 anterior column fractures, 5 anterior column plus posterior hemitransverse fractures, 8 double column fractures and one T-shaped fracture. The delay from injury to surgery averaged 6.5 days. All were treated with the technique of DAPSQ. Screw internal fixation of the quadrilateral area followed plate moulding via a single ilioinguinal ap-proach. Fixation with lag screws for the posterior column was added if necessary. Results The 18 pa-tients were followed up for 12 to 35 months (mean, 26 months). By the Matta criteria for fracture reduction, 9 cases were rated as excellent, 6 as good and 3 as poor. Bone healing was achieved within 2 to 4 months (mean, 3.5 months). By the modified Merle d’Aubigne & Postel criteria, the affected hips scored 9 to 18 points (mean, 16.3 points) at the final follow-ups, giving 7 excellent, 7 good, 2 fair and 2 poor cases. By the Harris evaluation, the affected hips scored 58 to 98 points (mean, 87.6 points), giving 7 excellent, 8 good, one fair and 2 poor cases. The postoperative complications included urinary tract infection in one, lesion of lateral femoral cutaneous nerve in one, heterotopic ossification (Brooker Grade Ⅰ ) in one, and traumatic osteoarthritis in 5 cases 2 of whom had to receive total hip arthroplasty. Conclusion The technique of DAPSQ is suitable for the treatment of acetabular fractures involving medial displacement of the quadrilateral surface in elderly patients, because it can provide and maintain stable fixation of the fracture in the quadri-lateral area and preserve hip joint function, leading to fine outcomes. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Bone plates; Aged

The influence in anterior column with posterior hemi-transverse fractures of the acetabulum fixed by DPASQ which caused by the stability of the contralateral pelvic ring:a finite element analysis

Objective To study the influence of sitting position in anterior column with the hemi-transverse fractures of the acetabulum fixed by dynamic anterior plate-screw system for quadrilateral area(DAPSQ) which caused by the the stability of the contralateral pelvic ring. Methods Using the finite element analysis method to build the pelvis model of right high anterior column with posterior hemi-transverse lesion fractures of the acetabulum, and fixing the right side of the acetabulum fractures by DAPSQ, we construct three sets of internal fixation models individually: keep the contralateral pelvic ring in its integrity(A), complete for superior and inferior ramus of pubis fracture internal fixation(B)and keep the contralateral superior and inferior ramus of pubis fractures unfixed(C), finally contract the displacement and stress distribution on the right side of the fracture between groups under load 600 N of physiological load imitating sitting position. Results It has no significant sense in the differences of longitudinal displacement of the dome region of acetabulum between the three internal fixation models of group A, group B and group C. The lateral displacements of posterior column inner lining were(0. 903±0. 034),(0. 910±0. 038),(1. 117± 0. 380) mm, the force on DASPQ square area screw shows that A> B> C and the differences are significant. Conclusion The biomechanical stability of anterior column with posterior hemi-transverse fractures of acetabulum fixed by DAPSQ is well, under the premise that the contralateral pelvic ring is stable. Key words: Pelvis; Acetabulum; Fracture; Biomechanics; Internal fixation; Finite element analysis

Finite element analysis of standing position in both-column with posterior hemi-transverse lesion fractures of the acetabulum fixed by dynamic anterior plate-screw system for quadrilateral area

Objective To explore biomechanical stability of fractures of the acetabulum fixed by dynamic anterior plate-screw system for quadrilateral area(DAPSQ) when pelvic ring was unstable. Methods To prepare right side of the anterior column with posterior hemi-transverse lesion fractures of the acetabulum(pelvis)by finite element analysis, DAPSQ(A), building on the left side of the superior ramus of pubis fracture and inferior ramus of pubis model on the basis of A model, prepare two kinds of model of the left side of the superior ramus fractures of pubis with fixed(B)and titanium plate fixation(C).Then, the same physiological load was exerted on different model respectively. At the end, the none-line solution was analyzed, analysis of the stress and displacement in model. Results After fracture fixation through the lateral and longitudinal displacement and the stress nephogram found after analysis and comparison, the transverse and longitudinal displacement is small with DAPSQ internal fixation when the stability of pelvic ring, accord with standard of reset, uniform stress distribution, no obvious phenomenon of highly concentrated, fixed intensity bigger, fixed the pelvis after more stable.But when accompanied by unstable pelvic ring road ahead for DAPSQ fracture line of vertical and horizontal displacement of the present B> C> A,A, B, C stations, the longitudinal displacement respectively(1. 315±0. 171),(1. 490±0. 247),(1. 334±0. 160) mm, lateral displacement of stations respectively(1. 185±0. 700),(1. 337±0. 080),(1. 198±0. 103)mm. Conclusion The pelvic ring must be stable when treatment of anterior column with posterior hemitransverse lesion fixed by DAPSQ. Key words: Pelvic ring; Acetabular; Fracture; Biomechanics; Finite element analysis

The Influence of Pelvic Ramus Fracture on the Stability of Fixed Pelvic Complex Fracture.

This study aims to evaluate the biomechanical mechanism of pelvic ring injury for the stability of pelvis using the finite element (FE) method. Complex pelvic fracture (i.e., anterior column with posterior hemitransverse lesion) combined with pelvic ramus fracture was used to evaluate the biomechanics stability of the pelvis. Three FE fracture models (i.e., Dynamic Anterior Plate-Screw System for Quadrilateral Area (DAPSQ) for complex pelvic fracture with intact pubic ramus, DAPSQ for complex pelvic fracture with pubic ramus fracture, and DAPSQ for complex pelvic fracture with fixed pubic ramus fracture) were established to explore the biomechanics stability of the pelvis. The pubic ramus fracture leads to an unsymmetrical situation and an unstable situation of the pelvis. The fixed pubic ramus fracture did well in reducing the stress levels of the pelvic bone and fixation system, as well as displacement difference in the pubic symphysis, and it could change the unstable situation back to a certain extent. The pelvic ring integrity was the prerequisite of the pelvic stability and should be in a stable condition when the complex fracture is treated.