Abstract
OBJECTIVE:
The acetabular buttress-plate has been widely used in treating difficult cases with satisfying clinical results. However, the biomechanical properties of a postoperative acetabular fracture fixed by the buttress-plate are not clear. The purpose of this study was to evaluate the biomechanical properties of stability after the anterior tube buttress-plate fixation of complex acetabular fractures in the quadrilateral area.
METHODS:
A construct was proposed based on anterior construct plate - 1/3 tube buttress plate fixation for acetabular both-column fractures. Two groups of six formalin-preserved cadaveric pelvises were analyzed: (1) group A, the normal pelvis and (2) group B, anterior construct plate-1/3 tube buttress plate with quadrilateral area fixation. The displacements were measured, and cyclical loads were applied in both standing and sitting simulations.
RESULTS:
As the load was added, the displacements were A<B, increasing in line. In the 600 N physiological loading, the differences were significant (standing position: p = 0.013; sitting position: p = 0.009) between groups A and B.
CONCLUSION:
The anterior construct plate - 1/3 tube buttress plate fixation provided a better stable construct for early sitting. The standing mode yielded more significant differences between the groups. Placing a 1/3 tube buttress-plate via an anterior approach is a novel method of providing quadrilateral area support in this setting.
Acetabular Fractures; Quadrilateral Area; Articular Comminution; Internal Fixation; Biomechanics
INTRODUCTION
Treating acetabular fractures in the quadrilateral area is one of the most challenging problems
in the orthopedic trauma department because such fractures often belong to the group of articular
comminuted fractures. The bone in the quadrilateral area is thin, and the anatomical site is deep.
The most difficult part of these bony deficits is that the screw can easily penetrate into the hip
(11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
). Acetabular both-column fractures are the most common
fracture in the quadrilateral area (11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
,22. Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results
in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am.
1996;78(11):1632-45.). We often select a multi-approach (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.) or
modified ilioinguinal approach (11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
) to expose this fracture
during the operation. Due to the presence of many postoperative complications, the reduction and
internal fixation of acetabular both-column fractures though a single anterior approach has been a
direction sought by many orthopedic doctors (44. El-khadrawe TA, Hammad AS, Hassaan AE. Indicators of outcome after internal
fixation of complex acetabular fractures. Alexandria Journal of Medicine. 2012;2(48):99-107,
http://dx.doi.org/10.1016/j.ajme.2011.12.005,
http://dx.doi.org/10.1016/j.ajme.2011.12.005.
http://dx.doi.org/10.1016/j.ajme.2011.12...
,55. Jeffcoat DM, Carroll EA, Huber FG, Goldman AT, Miller AN, Lorich DG, et al.
Operative treatment of acetabular fractures in an older population through a limited ilioinguinal
approach. J Orthop Trauma. 2012;26(5):284-9, http://dx.doi.org/10.1097/BOT.0b013e31821e10a2,
http://dx.doi.org/10.1097/BOT.0b013e31821e10a2.
http://dx.doi.org/10.1097/BOT.0b013e3182...
).
The main problem is the difficulty involved in fixing the posterior column fracture block
(quadrilateral area) through a single anterior approach. The lag screw through the anterior column
to the posterior column would produce a certain clinical result (11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
,66. Lin HH, Hung SH, Su YP, Chiu FY, Liu CL. Cerclage wiring in displaced associated
anterior column and posterior hemi-transverse acetabular fractures. Injury. 2012;43(6):917-20,
http://dx.doi.org/10.1016/j.injury.2012.01.016,
http://dx.doi.org/10.1016/j.injury.2012.01.016.
http://dx.doi.org/10.1016/j.injury.2012....
), but its fixation is eccentric (partial
posterior) and requires the fracture blocks of the anterior and posterior columns to not be crushed
(66. Lin HH, Hung SH, Su YP, Chiu FY, Liu CL. Cerclage wiring in displaced associated
anterior column and posterior hemi-transverse acetabular fractures. Injury. 2012;43(6):917-20,
http://dx.doi.org/10.1016/j.injury.2012.01.016,
http://dx.doi.org/10.1016/j.injury.2012.01.016.
http://dx.doi.org/10.1016/j.injury.2012....
,77. Vanderschot P. Treatment options of pelvic and acetabular fractures in patients
with osteoporotic bone. Injury. 2007;38(4):497-508, http://dx.doi.org/10.1016/j.injury.2007.01.021,
http://dx.doi.org/10.1016/j.injury.2007.01.021.
http://dx.doi.org/10.1016/j.injury.2007....
). The cerclage
wires also produce some good results (88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
). However, more
complex hardware combinations necessitate larger exposures, which are often associated with higher
rates of infection and overall complications (99. Gililland JM, Anderson LA, Henninger HB, Kubiak EN, Peters CL. Biomechanical
analysis of acetabular revision constructs: Is pelvic discontinuity best treated with bicolumnar or
traditional unicolumnar fixation?. J Arthroplasty. 2013;28(1):178-86,
http://dx.doi.org/10.1016/j.arth.2012.04.031,
http://dx.doi.org/10.1016/j.arth.2012.04.031.
http://dx.doi.org/10.1016/j.arth.2012.04...
).
Given these issues, the fixation technology of the bone surface (buttress-plate) was used to fix
the posterior column fracture block. A titanium plate combined with 1/3 tube buttress-plate has been
widely used and produces a better therapeutic effect (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.,44. El-khadrawe TA, Hammad AS, Hassaan AE. Indicators of outcome after internal
fixation of complex acetabular fractures. Alexandria Journal of Medicine. 2012;2(48):99-107,
http://dx.doi.org/10.1016/j.ajme.2011.12.005,
http://dx.doi.org/10.1016/j.ajme.2011.12.005.
http://dx.doi.org/10.1016/j.ajme.2011.12...
). The stability of elastic fixation to the quadrilateral area by
the tube buttress-plate has always been controversial (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.,88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
). Stability is essential because an ingrowth
component can only be successful if it is adequately stabilized against the host bone to allow host
bone ingrowth to occur (99. Gililland JM, Anderson LA, Henninger HB, Kubiak EN, Peters CL. Biomechanical
analysis of acetabular revision constructs: Is pelvic discontinuity best treated with bicolumnar or
traditional unicolumnar fixation?. J Arthroplasty. 2013;28(1):178-86,
http://dx.doi.org/10.1016/j.arth.2012.04.031,
http://dx.doi.org/10.1016/j.arth.2012.04.031.
http://dx.doi.org/10.1016/j.arth.2012.04...
). There are currently no
biomechanical evaluations in the literature comparing buttress-plate for the treatment of complex
acetabular fractures. Therefore, this study evaluated the biomechanics of a tube buttress-plate in
both standing (11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
) and sitting (1010. Gao YC, Guo Z, Fu J, Tian WJ. Three-dimensional finite element analysis of the
pelvis in sitting stance. Journal of Clinical Rehabilitative Tissue Engineering Research.
2011;22(15):3997-4001.) simulations.
METHODS
Specimens
We selected six formalin-preserved cadaveric pelvises for this investigation. Six normal human specimens that included the fourth lumbar vertebra and proximal 1/3 of the femoral shaft were obtained from the Department of Anatomy of Southern Medical University. These specimens had no known metabolic bone disease or tumors. The trabecular appearance and bony quality were examined, and bone abnormalities were ruled out by a standard anteroposterior X-ray. The soft tissue was removed, except the sacrum, sacroiliac joint, hip joint capsule, ligaments of the sacral spine, sacral tubercle and obturator internus (Figure 1). Only one hip was used for testing for each hip surgery. We selected the reconstruction plate, 1/3 tube and titanium screws (3.5 mm) of AO, and ZWICKZ100 material machine (Germany ZWICKZ, a precision of 0.1%, Department of Mechanical Room of the Wuhan University of Technology).
Displacement measurement
The specimen was fixed in the position of standing or sitting (Figure 2) on the pelvis as previously described by Pierannunzii L (11. Pierannunzii L, Fischer F, Tagliabue L, Calori GM, d'Imporzano M. Acetabular
both-column fractures: essentials of operative management. Injury. 2010;41(11):1145-9,
http://dx.doi.org/10.1016/j.injury.2010.08.011,
http://dx.doi.org/10.1016/j.injury.2010.08.011.
http://dx.doi.org/10.1016/j.injury.2010....
) and Gao YC (1010. Gao YC, Guo Z, Fu J, Tian WJ. Three-dimensional finite element analysis of the
pelvis in sitting stance. Journal of Clinical Rehabilitative Tissue Engineering Research.
2011;22(15):3997-4001.). Then, the specimen was
treated repeatedly with loads from 400 to 700 Newtons. In the standing position, the lateral
displacement of the posterior column fracture in the inner wall and the longitudinal displacement of
the anterior inferior iliac spine were measured with a multifunctional digital dial gauge (Beijing
Deli love Monitoring Technology, Beijing, China). In the sitting position, the lateral displacement
of the posterior column fracture in the inner wall was measured with a multifunctional digital dial
gauge, and the overall axial displacement of the pelvis was measured with the beam sensor of the
ZwickZ100 electronic universal testing machine. The stiffness of the specimens was calculated.
First, we tested the six normal human pelvises in both the standing and sitting simulations as the
control group. Then, we produced high both-column fractures using a wire saw on one hip (Figure 3) and fixed the fracture using anterior construct plate -1/3
tube buttress-plate fixation (group B, Figure 4). We tested
the fractured pelvic again in the standing and sitting positions consecutively.
The anterior construct plate-1/3 tube buttress-plate fixed the specimen. (A. General view, B. CT reconstruction, C. X-rays scan).
Analysis
According to the matta standard (22. Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am. 1996;78(11):1632-45.), the displacement of a fracture after internal fixation of less than 1 mm indicated anatomic reduction; if the lateral displacement of the posterior column wall was greater than 1 mm, the femoral head would appear central dislocation; and if the longitudinal displacement of the anterior inferior iliac spine was greater than 1 mm, the femoral head would appear upward dislocation.
The “Paired-Sample T Test” was used to assess the significance of the differences between the groups for each index of measurement. Initially, all conditions were considered together; subsequently, the tests were conducted separately for each position by the “2-Repeating Factor of ANOVA”. An alpha-level of 0.05 was used for each test to test the differences between the simulations.
All data were expressed as the means±SE unless otherwise stated, and the statistical analysis was performed with SPSS 13.0 statistics software for Windows (SPSS, Chicago, IL).
RESULTS
The fracture blocks of the anterior and posterior columns in the specimens after internal fixation were firmly fixed immediately, resulting in anatomic reduction. The soft tissue (the sacrotuberous ligament, sacrospinous ligament and obturator internus) was taut. The screws and plates did not crack during the testing process. The maximum separation was less than 2 mm. After the removal of the load, the acetabular plate and fixation returned to their initial form or state.
The relationship between load and displacement
As the load was added, the displacements were A<B, increasing in line. In the standing position, the displacement of the specimens in group B under the 400 N load was greater than 1 mm, indicating that the dislocation of the femoral head began to appear under the 400 N load. In the inner wall, horizontal displacement of more than 1 mm appeared at the following loads: 400 N in 1 case, 500 N in 1 case, 600 N in 1 case, and 700 N in 2 cases. In the anterior wall, longitudinal displacement of more than 1 mm appeared at the following loads: 400 N in 1 case, 500 N in 2 cases, 600 N in 3 cases, and 700 N in 3 cases. The statistical analysis showed that there was a significant difference between the horizontal and vertical displacements (p<0.05) in group A to group B (Tables 1) and 2).
In the sitting position, the lateral displacement of the posterior column-inner wall in group B was absolutely within 0.5(mm and thus was without dislocation. The statistical analysis showed that although the numerical value of the lateral displacement of the posterior column-inner wall in group B was greater than that in group A, there was no significant difference (p>0.05) (Table 3). The axial stiffness of the pelvis in group A was significantly larger than that in group B (p<0.01) (Table 4).
Quantitative analysis of the test results on the physiological load (600 N)
In the standing position, the longitudinal stiffness of the anterior wall was 2883.9±1901.2 N/mm in group A and 1015.5±365.3 N/mm in group B. We analyzed the two measuring indices (the lateral displacement of the inner wall and the longitudinal stiffness of the anterior) comprehensively using the statistical method of "2 Repeating Factor Of ANOVA ", which showed a significant difference (F = 14.3, p = 0.013) between groups A and B. In the sitting position, we analyzed the two measuring indices (the lateral displacement of the inner wall and the axial stiffness of the pelvis) comprehensively, which showed a significant difference (F = 16.9, p = 0.009) between groups A and B.
DISCUSSION
The acetabulum represents a basin-like anatomic structure that bears the body's weight,
receives the resultant force from the ground, and accommodates ambulatory activity and hip joint
mobility (1111. Kubota M, Uchida K, Kokubo Y, Shimada S, Matsuo H, Yayama T, et al. Changes in
gait pattern and hip muscle strength after open reduction and internal fixation of acetabular
fracture. Arch Phys Med Rehabil. 2012;93(11):2015-21, http://dx.doi.org/10.1016/j.apmr.2012.01.016,
http://dx.doi.org/10.1016/j.apmr.2012.01.016.
http://dx.doi.org/10.1016/j.apmr.2012.01...
). Open anatomic reduction of the articular
surface combined with rigid internal fixation and early mobilization is the standard current
treatment for injuries to this region (1111. Kubota M, Uchida K, Kokubo Y, Shimada S, Matsuo H, Yayama T, et al. Changes in
gait pattern and hip muscle strength after open reduction and internal fixation of acetabular
fracture. Arch Phys Med Rehabil. 2012;93(11):2015-21, http://dx.doi.org/10.1016/j.apmr.2012.01.016,
http://dx.doi.org/10.1016/j.apmr.2012.01.016.
http://dx.doi.org/10.1016/j.apmr.2012.01...
,1212. Briffa N, Pearce R, Hill AM, Bircher M. Outcomes of acetabular fracture fixation
with ten years' follow-up. J Bone Joint Surg Br. 2011;93(2):229-36,
http://dx.doi.org/10.1302/0301-620X.93B2.24056,
http://dx.doi.org/10.1302/0301-620X.93B2.24056.
http://dx.doi.org/10.1302/0301-620X.93B2...
). Maintaining stability of the joint is very important (99. Gililland JM, Anderson LA, Henninger HB, Kubiak EN, Peters CL. Biomechanical
analysis of acetabular revision constructs: Is pelvic discontinuity best treated with bicolumnar or
traditional unicolumnar fixation?. J Arthroplasty. 2013;28(1):178-86,
http://dx.doi.org/10.1016/j.arth.2012.04.031,
http://dx.doi.org/10.1016/j.arth.2012.04.031.
http://dx.doi.org/10.1016/j.arth.2012.04...
). The stability of the hip mainly depends on the blocking effect
of the acetabular bone. The quadrilateral area (square area) is located in the inner side of the
acetabular posterior column. Comminuted fractures are likely caused by strong violence to the
longitudinal femoral neck. The femoral head with the fracture blocks would transpose to the
intrapelvic direction (88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
,1313. Laflamme GY, Hebert-Davies J, Rouleau D, Benoit B, Leduc S. Internal fixation of
osteopenic acetabular fractures involving the quadrilateral plate. Injury. 2011;42(10):1130-4,
http://dx.doi.org/10.1016/j.injury.2010.11.060,
http://dx.doi.org/10.1016/j.injury.2010.11.060.
http://dx.doi.org/10.1016/j.injury.2010....
). The bone in the quadrilateral area and the iliopectineal bulge of the anterior column
are thin and close to the joint (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.), limiting the types of
fixation that can be used in this area. The blocking effect of the bone block in the quadrilateral
area is often neglected. The existing classification of acetabular fractures does not list
quadrilateral area fractures separately, although except for simple fractures, all other fractures
involve this area according to the classification of Letournel and Judet. As society ages, the
number of osteoporosis fractures of the quadrilateral area is increasing. Effectively fixing such
fractures is becoming an urgent issue. To avoid the risk area, the current treatment basically only
involves no fixation or indirect fixation. When the screw is away from the acetabular fracture, the
reliable degree of fixation decreases by approximately 50% (1414. Shazar N, Brumback RJ, Novak VP, Belkoff SM. Biomechanical evaluation of
transverse acetabular fracture fixation. Clin Orthop Relat Res. 1998;(352):215-22.), and the stability of the acetabulum decreases (1515. Harnroongroj T, Asavamongkolkul A, Chareancholvanich K. Reconstruction of the
pelvic brim and its role in the reduction accuracy of displaced T-shaped acetabular fracture.
J Med Assoc Thai. 2000;83(5):483-93.,1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.). In general, only the anterior reconstruction
titanium plate-screw system shows difficulty in fully achieving reliable fixation (88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
,1414. Shazar N, Brumback RJ, Novak VP, Belkoff SM. Biomechanical evaluation of
transverse acetabular fracture fixation. Clin Orthop Relat Res. 1998;(352):215-22.,1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.). The plate of the anterior column or posterior column only played a supporting
role. Palliative care is only a prelude to joint replacement.
Historically, hip biomechanics suggested that the bearing force of the acetabulum could be
divided into two components in the horizontal and vertical directions of the coronal plane (1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.,1717. Mao BY. Biomechanical analysis of surgical revision in artificial hip joint.
Orthopedic J China. 2003;11(10):700-2.). The shear stress in
the horizontal direction often promoted the fracture block to emerge as a transverse separation
(88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
,1313. Laflamme GY, Hebert-Davies J, Rouleau D, Benoit B, Leduc S. Internal fixation of
osteopenic acetabular fractures involving the quadrilateral plate. Injury. 2011;42(10):1130-4,
http://dx.doi.org/10.1016/j.injury.2010.11.060,
http://dx.doi.org/10.1016/j.injury.2010.11.060.
http://dx.doi.org/10.1016/j.injury.2010....
,1818. Ferguson TA, Patel R, Bhandari M, Matta JM. Fractures of the acetabulum in
patients aged 60 years and older: an epidemiological and radiological study. J Bone Joint Surg
Br. 2010;92(2):250-7, http://dx.doi.org/10.1302/0301-620X.92B2.22488,
http://dx.doi.org/10.1302/0301-620X.92B2.22488.
http://dx.doi.org/10.1302/0301-620X.92B2...
,1919. Cole JD, Bolhofner BR. Acetabular fracture fixation via a modified Stoppa
limited intrapelvic approach. Description of operative technique and preliminary treatment results.
Clin Orthop Relat Res. 1994;(305):112-23.). We should emphasize
the reduction and stability of the quadrilateral area in the operation, not only paying attention to
reducing and fixing the surface fracture of the posterior column (1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.). The lag screw fixation was eccentric and could play a certain role in fixation.
However, not all acetabular fractures are amenable to the placement of an interfragmentary lag screw
(66. Lin HH, Hung SH, Su YP, Chiu FY, Liu CL. Cerclage wiring in displaced associated
anterior column and posterior hemi-transverse acetabular fractures. Injury. 2012;43(6):917-20,
http://dx.doi.org/10.1016/j.injury.2012.01.016,
http://dx.doi.org/10.1016/j.injury.2012.01.016.
http://dx.doi.org/10.1016/j.injury.2012....
,77. Vanderschot P. Treatment options of pelvic and acetabular fractures in patients
with osteoporotic bone. Injury. 2007;38(4):497-508, http://dx.doi.org/10.1016/j.injury.2007.01.021,
http://dx.doi.org/10.1016/j.injury.2007.01.021.
http://dx.doi.org/10.1016/j.injury.2007....
,2020. Mehin R, Jones B, Zhu Q, Broekhuyse H. A biomechanical study of conventional
acetabular internal fracture versus locking plate fixation. Can J Surg.
2009;52(3):221-8.), and the fracture may be displaced during tightening of the
interfragmentary lag screw (2020. Mehin R, Jones B, Zhu Q, Broekhuyse H. A biomechanical study of conventional
acetabular internal fracture versus locking plate fixation. Can J Surg.
2009;52(3):221-8.).
Given the characteristics of the anatomy and acetabulum biomechanics, a reconstruction titanium
plate-1/3 tube type elastic buttress-plate, which is typically used as the fixation technology of
the bone surface, is an ideal internal fixation. It has the advantage of a simple application during
the operation. The routine method is almost unable to achieve fixation to the acetabular fossa and
quadrilateral area as well as the 1/3 tube (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.,44. El-khadrawe TA, Hammad AS, Hassaan AE. Indicators of outcome after internal
fixation of complex acetabular fractures. Alexandria Journal of Medicine. 2012;2(48):99-107,
http://dx.doi.org/10.1016/j.ajme.2011.12.005,
http://dx.doi.org/10.1016/j.ajme.2011.12.005.
http://dx.doi.org/10.1016/j.ajme.2011.12...
,1212. Briffa N, Pearce R, Hill AM, Bircher M. Outcomes of acetabular fracture fixation
with ten years' follow-up. J Bone Joint Surg Br. 2011;93(2):229-36,
http://dx.doi.org/10.1302/0301-620X.93B2.24056,
http://dx.doi.org/10.1302/0301-620X.93B2.24056.
http://dx.doi.org/10.1302/0301-620X.93B2...
).
Cole (1919. Cole JD, Bolhofner BR. Acetabular fracture fixation via a modified Stoppa
limited intrapelvic approach. Description of operative technique and preliminary treatment results.
Clin Orthop Relat Res. 1994;(305):112-23.) first reported the use of elastic buttress-plate
fixation to resist the shear stress of the inner wall. The proximal end of the plate was fixed to
the iliac bone. He highlighted that an excessive correction plate, which is similar to a spring, was
used to hold the pieces of a medial wall fracture downward in the pelvic side wall. A recent
clinical study showed that elastic plate stability was reduced by postoperative turning during
nursing care and that the plate was remodeled easily, resulting in the loss of its fixation role
after fatigue. It also has the potential to cut pelvic organs. Farid (88. Farid YR. Cerclage wire-plate composite for fixation of quadrilateral plate
fractures of the acetabulum:a checkrein and pulley technique. J Orthop Trauma.
2010;24(5):323-8, http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe,
http://dx.doi.org/10.1097/BOT.0b013e3181c90bbe.
http://dx.doi.org/10.1097/BOT.0b013e3181...
) made some improvements with the addition of cerclage wire in the elastic steel
plate to strengthen the fixation. To provide adequate pressure, the wire needed to be thread through
the greater sciatic notch, and stripping during the operation was significant. All of these factors
can easily injure the sciatic nerve and peripheral vascular system. Pan (33. Pan ZJ, Chen HX. Clinical department of orthopedics trauma diseases.Beijing,
Scientific And Technical Documentation Press. 2010;345-7.) added the 1/3 tubular plate under the anterior column reconstruction titanium
plate and attempted to rely on the extrusion of the titanium plate to reinforce the elastomeric
tube, thereby fixing the bone block. Laflamme (1313. Laflamme GY, Hebert-Davies J, Rouleau D, Benoit B, Leduc S. Internal fixation of
osteopenic acetabular fractures involving the quadrilateral plate. Injury. 2011;42(10):1130-4,
http://dx.doi.org/10.1016/j.injury.2010.11.060,
http://dx.doi.org/10.1016/j.injury.2010.11.060.
http://dx.doi.org/10.1016/j.injury.2010....
) performed
a follow-up study over 4.2 years in elderly people using a buttress-plate to fix fracture blocks in
the quadrilateral area and found that the anatomical reduction rate was 90.5%. There are currently
no biomechanical evaluations in the literature comparing buttress-plate for the treatment of complex
acetabular fractures. Therefore, this study evaluated the tube buttress-plate.
The horizontal displacement in the posterior column wall reflects the shear resistance of the internal fixator after the operation. Upward or slip displacements, which are produced by the push of the femoral head-acetabular roof, reflect the overall standing stability of the hip. The longitudinal displacement of the sacroiliac joint mainly comprises the longitudinal stiffness of the complete pelvis. However, the stiffness of the entire pelvis is not equivalent to the stiffness of the sacroiliac joint (2121. Wang F, Liu R, Wang QG, Shi DF, Yang Q, Chen B, et al. Testing of axial stiffness of human pelvis under gradient vertical loads. J Med Biomechanics. 2011;1(26):57-61.). The stability of the hip also produces axial stiffness in the pelvis. In the same pelvis, the difference in the axial stiffness reflects the stability of the fixation. We selected cadaveric specimens to create a high both-column fracture model. According to the stress distribution of the hip after loading in the coronal plane, the results showed the following: 1. as the load increased from 400 N to 700 N, the displacement increased, which was consistent with the law of conventional dynamics; and 2. in the standing position, the displacements in group B were larger. When the load exceeded 400 N, dislocation of the femoral head began to appear. Compared with the normal acetabulum, there was a significant difference in group B (Tables 1) and 2). In the sitting position, the overall axial stiffness of the pelvis was reduced (Tables 3) and 4). The lateral displacement of the inner wall in the posterior column was within 0.5 mm, with no dislocation, which was not significantly different (Table 3).
The patients are in a wheelchair for 2-6 weeks after the operation. This stage is the critical period for fracture repair and creation of the articular surface as well as for further functional exercise. Standing early is vital to reduce the long-term complications of bed rest and recover the patient's confidence. However, if functional exercises are started too early, the loss outweighs the gain. At home and abroad, there are few reports that note that patients need to take care of the physiological conditions of fracture reduction after the operation (1010. Gao YC, Guo Z, Fu J, Tian WJ. Three-dimensional finite element analysis of the pelvis in sitting stance. Journal of Clinical Rehabilitative Tissue Engineering Research. 2011;22(15):3997-4001.). We tested the positions of sitting and standing in this experiment, retaining portions of the soft tissue. We also fully simulated the postoperative physiological status of the patients, which was close to the clinical status. In group B, the experimental results showed that the hip was prone to instability in the standing position. The shear force of the 1/3 tube type titanium plate was poor. Although the axial stiffness of the pelvis in the sitting position was poorer than that of the normal pelvis, acetabulum fractures showed a satisfactory reduction on physiological load. Thus, sitting early is safe.
In general, as long as the patient's condition allows it, the operation of the acetabular fracture should be performed 3-7 days and no more than 2 weeks after the injury. Otherwise, the difficulty of the operation would increase (2222. Cai XH, Chen ZH, Xu YN, Huang JF, Xu F, Liu XM, et al. Relevancy factor analysis on the choice of operative approaches for different acetabular fractures. Orthopedic J China. 2006;20(14):1526-8.). Thus, because the healing rate of acetabular fractures is very rapid, the fractures will tend to be stable after 2 or 3 weeks because they can easily form a localized scab. Along with the process of fracture healing, the fixation stability of an acetabular fracture will be enhanced, that is, the inner fixation would bear weight-stress for a short time only. Its main contribution of share the weight is going on in the initial 2 weeks. All of these factors may explain why single-point elasticity fixation (1/3 tube type titanium plate) can obtain satisfactory results in the fixing portion of the posterior column fracture.
In addition, the proper selection of the operation approach will reduce the degree of difficulty
and improve the quality of the reduction (2323. Yu LX, Wang L, Liu QP, Zhang H. Surgical therapy of displaced complex acetabular
fractures and analysis of influence factors in 40 patients. Orthopedic J China.
2012;8(20):685-7.). In the
reduction of both column acetabular fractures, we often adopt the combination approach, which needs
a wide range of stripping and a long operation time. Postoperative heterotopic ossification also
occurs at a high rate. We selected a single ilioinguinal approach in the fixation of an anterior
construct plate-1/3 tube buttress plate, fully utilizing the advantages of the anterior approach,
which are essential to maximize the union rates and minimize the complications in these difficult
cases (2424. Qin XD, Li X, LV TR, Song LJ, Zhang N, Fan WM. The subinguinal approach for
treatment of acetabular fractures. Chin J Orthop Traumatol.
2010;10(12):936-9.). The ilioinguinal approach also could be able to
fix most complex fractures of the acetabulum(2525. Ma WH, Xu RM, Xue B, Feng JX. Surgical treatment of severe comminuted acetabular
fractures. J Bone Joint Injury. 2003;2(18):88-90.). Therefore,
the reduction and internal fixation of both-column fractures using a single anterior approach has
been the direction taken by many orthopedic doctors (44. El-khadrawe TA, Hammad AS, Hassaan AE. Indicators of outcome after internal
fixation of complex acetabular fractures. Alexandria Journal of Medicine. 2012;2(48):99-107,
http://dx.doi.org/10.1016/j.ajme.2011.12.005,
http://dx.doi.org/10.1016/j.ajme.2011.12.005.
http://dx.doi.org/10.1016/j.ajme.2011.12...
,55. Jeffcoat DM, Carroll EA, Huber FG, Goldman AT, Miller AN, Lorich DG, et al.
Operative treatment of acetabular fractures in an older population through a limited ilioinguinal
approach. J Orthop Trauma. 2012;26(5):284-9, http://dx.doi.org/10.1097/BOT.0b013e31821e10a2,
http://dx.doi.org/10.1097/BOT.0b013e31821e10a2.
http://dx.doi.org/10.1097/BOT.0b013e3182...
). However, the main problem is that the block posterior column
and the quadrilateral area are difficult to fix. The 1/3 tube plate had better results than
palliative care (no fixation or indirect fixation) in weakening the shear stress on the inner wall
but is poorer to prevent separation of the distal bone block. More work is needed to search for a
suitable fixator.
A few points should be noted. First, we only used six specimens as representatives because human
pelvis specimens are very precious. Second, we elected to pursue a repeated measures design rather
than a matched pair design for this investigation. Six specimens were tested four successive times.
To reduce the effect of the repeated test impacts, the experiments were performed randomly in the
simulated positions. At the same time, the maximum load (700 N) was within the yielding point of the
pelvises (2626. Liu Y, Chen FZ, Mei HJ, You H, Yang Q, Wang Z, et al. Biomechanical studies of
normal pelvis in static standing position . Clin Med Eng. 2010;17(6):7-12.). The mechanical strength had no obvious effect
on the elastic deformation. Third, although there are individual differences among the experimental
samples, the experimental load was selected based on the characteristics of each specimen (1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.,2020. Mehin R, Jones B, Zhu Q, Broekhuyse H. A biomechanical study of conventional
acetabular internal fracture versus locking plate fixation. Can J Surg.
2009;52(3):221-8.). Therefore, we
selected a large observation range, from 400 to 700 N, and did not perform the analysis one by one,
but rather only focused on the analysis of the 600 N physiological weight (1010. Gao YC, Guo Z, Fu J, Tian WJ. Three-dimensional finite element analysis of the
pelvis in sitting stance. Journal of Clinical Rehabilitative Tissue Engineering Research.
2011;22(15):3997-4001.,1616. Wu XB, Zhang Q, Guo MK, Zhang YZ. Biomechanical comparison of 4 plateinternal
fixation methods for simulated fractures of acetabular posterior column. Acta Acad Med Militaris
Tertiae. 2010;7(32):665-8.). In addition, Vailas (2727. Vailas JC, Hurwitz S, Wiesel SW. Posterior acetabular fracture-dislocations:
fragment size, joint capsule, and stability. J Trauma. 1989;29(11):1494-6.) highlighted that the function of the soft tissue could not be
ignored. The integrity of the articular capsule determined the stability of the hip joint. To be
close to the actual clinical state, we retained the important ligaments and muscles for convenient
measurements in this experiment, which was different from previous studies (99. Gililland JM, Anderson LA, Henninger HB, Kubiak EN, Peters CL. Biomechanical
analysis of acetabular revision constructs: Is pelvic discontinuity best treated with bicolumnar or
traditional unicolumnar fixation?. J Arthroplasty. 2013;28(1):178-86,
http://dx.doi.org/10.1016/j.arth.2012.04.031,
http://dx.doi.org/10.1016/j.arth.2012.04.031.
http://dx.doi.org/10.1016/j.arth.2012.04...
,2020. Mehin R, Jones B, Zhu Q, Broekhuyse H. A biomechanical study of conventional
acetabular internal fracture versus locking plate fixation. Can J Surg.
2009;52(3):221-8.).
The authors wish to thank Zhu Jian (Department of Thoracic Cardiovascular Surgery, Wuhan General Hospital of Guangzhou Command, Wuhan, People's Republic of China) for his careful revision of the manuscript and excellent technical assistance.
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-
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Publication Dates
-
Publication in this collection
July 2013
History
-
Received
25 Jan 2013 -
Reviewed
17 Mar 2013 -
Accepted
17 Mar 2013