01.12.2015 | Research article | Ausgabe 1/2015 Open Access

Comparison of reconstruction plate screw fixation and percutaneous cannulated screw fixation in treatment of Tile B1 type pubic symphysis diastasis: a finite element analysis and 10-year clinical experience
- Zeitschrift:
- Journal of Orthopaedic Surgery and Research > Ausgabe 1/2015
Competing interests
Authors’ contributions
Introduction
Materials and methods
Part of finite element analysis
Part
|
Nodes
|
Element number
|
---|---|---|
Left ilium
|
63,500
|
322,214
|
Right ilium
|
40,508
|
205,408
|
Left sacroiliac joint
|
78,380
|
399,129
|
Right sacroiliac joint
|
79,319
|
404,146
|
Sacrum
|
72,696
|
375,426
|
Cannulated screw
|
16,145
|
75,674
|
Plate + screw
|
65,354
|
324,089
|
Materials
|
Elastic modulus
|
Poisson ratio
|
Friction coefficient
|
---|---|---|---|
E (MPa)
|
μ
|
f
|
|
Titanium plate
|
110,000
|
0.30
|
0.45
|
Titanium screw
|
110,000
|
0.30
|
–
|
Articular cartilage
|
11.9–0.48
|
0.40
|
0.0024 ~ 0.24
|
Cortical bone
|
17,000
|
0.3
|
0.4
|
Cancellous bone
|
129
|
0.2
|
0.4
|
Ligaments
|
K (N/mm)
|
Number of springs
|
---|---|---|
Anterior sacroiliac
|
1500
|
30
|
Long posterior sacroiliac
|
5000
|
16
|
Short posterior sacroiliac
|
8000
|
25
|
Interspinous
|
4000
|
21
|
Superior pubic
|
250
|
12
|
Arcuate pubic
|
250
|
12
|
Sacrospinous
|
5000
|
16
|
Sacrotuberous
|
9000
|
16
|
Simulation of two operational fixation models for PSD
Contact, constraint, and load of three-dimensional finite element model
Part of clinical comparative study
Surgical technique
Statistical analysis
Results
Finite element analysis
Analysis of the whole stress
Anterior ring
|
Posterior ring
|
|||||
---|---|---|---|---|---|---|
RPSF
|
PCSF
|
(RPSF − PCSF)/RPSF
|
RPSF
|
PCSF
|
(RPSF − PCSF)/RPSF
|
|
The von Mises stress (MPa)
|
[0.212–1.132]
|
[0.336–1.004]
|
−58.49~11.31 %
|
[0.801–3.122]
|
[0.787–1.989]
|
17.48~36.29 %
|
The displacement (mm)
|
[0.051–0.201]
|
[0.047–0.059]
|
7.84~70.65 %
|
[0.031–0.153]
|
[0.056–0.097]
|
−80.6~36.6 %
|
Displacement of the pelvis
Stress analysis of cannulated screw and plate
Clinical and radiographic outcomes
PCSF group
|
RPSF group
|
T
|
P value
|
|
---|---|---|---|---|
Number
|
24
|
27
|
–
|
–
|
Age
|
33.4 ± 9.1
|
34.8 ± 11.7
|
–
|
–
|
Gender
|
15 males, 9 females
|
19 males, 8 females
|
–
|
–
|
Operative time (min)
|
26.3 ± 5.9
|
68.9 ± 13.6
|
−14.771
|
0.000
|
Intra-operative blood loss (ml)
|
9.6 ± 5.7
|
171.9 ± 68.3
|
−12.294
|
0.000
|
Length of skin scar (cm)
|
1.8 ± 0.6
|
8.1 ± 1.1
|
−24.864
|
0.000
|
Pre-operation
|
3 months after operation
|
Final follow-up
|
|
---|---|---|---|
PCSF group
|
47.58 ± 14.24
|
4.63 ± 1.06
*
|
4.84 ± 1.21
**
|
RPSF group
|
43.52 ± 11.31
|
4.55 ± 1.04
***
|
4.53 ± 1.16
****
|
T value
|
1.135
|
0.261
|
0.928
|
P value
|
0.262
|
0.795
|
0.358
|
PCSF group
|
RPSF group
|
P
|
|
---|---|---|---|
(
N = 24)
|
(
N = 27)
|
||
Wound infection
a
|
1
|
2
|
1.000
|
Implant failure
a
|
2
|
2
|
1.000
|
Revision surgery
b
|
1
|
1
|
1.000
|
Excellent
|
Good
|
Fair
|
Poor
|
P
|
|
---|---|---|---|---|---|
(>85)
|
(70–84)
|
(55–69)
|
(<55)
|
||
PCSF group
|
18
|
5
|
1
|
0
|
0.814
|
RPSF group
|
18
|
7
|
2
|
0
|