From January 2010 to December 2017, a total of 191 children with pelvic fractures were admitted to our hospital. Among them, 24 children(12.57%) with acetabular fractures, 15 children(7.85%) with Triradiate cartilage injuries. These children with TCI, only 8 cases were diagnosed at the first admission, four cases were diagnosed during follow-up, and 3 cases were found during the review. Among the 15 children, 10 were males, and 5 were females, ranging from 1.4 to 9.8 years old, with an average of 5.6 years old. Among them, 4 cases were under three years old, 5 cases were 3 to 6 years old, and 7 cases were over six years old. There were 12 cases of traffic accident injuries, 2 cases of crush injuries, and 1 case of fall injuries. Among the 15 children, 3 cases involved bilateral triradiate cartilage, and 12 cases of unilateral injury, totalling 18 hips. One hip with type I injury, nine hips with type II injury, and one hip with type V injury. Seven hips cannot be classified according to the Bucholz classification, of which two hips are fracture lines that entirely through the triradiate cartilage and involve the metaphyses on both sides, similar to type IV epiphyseal injuries of Salter Herris classification, so we supplement the classification as type IV; The other 5 hips did not show any triradiate cartilage involved at first X-ray and CT examination, only the fracture of the proximal suprapubic branch could be found, but in the later follow-up, it was found that the bone bridge was formed medial to inside the triradiate cartilage, we tentatively determined it as a type VI injury. There were 7 cases with severe joint dislocation, including 3 cases with pubic symphysis diastasis(PSD), 4 cases with sacroiliac joint dislocation(SIJD), and 1 case with PSD and SIJD. 8 patients with TCI were treated conservatively, including bed rest, external brace fixation, lower extremity skin traction, and then gradually bearing weight. Seven children with severe pelvic fractures were treated with closed reduction and external orthofix fixation or open reduction and internal fixation(ORIF).
During the follow-up, two children’s parents were unwilling to cooperate with the follow-up for their children had undergone high amputation due to severe damage to their lower limbs, and one child lost to follow-up. A total of 12 children were followed up completely. The follow-up time was 1.5 to 7.8 years, with an average of 5 years. The general information on admission of the children is shown in Table 1. The hip function of children was based on HHS (excellent 91–100; good 81–90; fair 71–80; poor 70 or less). Among the 12 children followed up, 8 cases were excellent, and 4 cases were good. The follow-up results are shown in Table 2. The AI, D/W, and AHI were measured by pelvic X-rays to assess the development of the acetabulum and the subluxation of the femoral head. Eight cases had bone bridges formed around triradiate cartilage, and 5 cases had triradiate cartilage premature closure, 2 cases had acetabular dysplasia, and 4 cases had femoral head subluxation.
Table 1
General data of 12 children with Triradiate cartilage injury.
case
|
sex
|
Age
|
side
|
type
|
location
|
complications
|
treatment
|
A
|
F
|
6y
|
L/R
|
II/I
|
Left iliopubic branch, Right pubis
|
PSD
|
Closed reduction and external stent fixation
|
B
|
M
|
6.2y
|
L
|
VI
|
Suprapubic branch
|
SIJD
|
Closed reduction and external stent fixation
|
C
|
M
|
1.4y
|
R
|
VI
|
Suprapubic branch
|
No
|
External brace fixation
|
D
|
F
|
3y
|
L/R
|
VI/VI
|
Suprapubic branch
|
No
|
Lower limb traction + External brace fixation
|
E
|
M
|
5.1y
|
R
|
IV
|
Iliosciatic branch
|
No
|
Lower limb traction + External brace fixation
|
F
|
F
|
2.3y
|
L/R
|
II/II
|
Bilateral ischiopubicbranch
|
PSD
|
Closed reduction and external stent fixation
|
G
|
M
|
4y
|
L
|
V
|
Left iliosciaticbranch
|
No
|
External brace fixation
|
H
|
M
|
5y
|
L
|
II
|
ischiopubicbranch
|
SIJD
|
Closed reduction and external stent fixation
|
I
|
M
|
2.2y
|
R
|
II
|
ischiopubicbranch
|
PSD
|
Closed reduction and external stent fixation
|
J
|
M
|
8.5y
|
R
|
II
|
ischiopubicbranch
|
No
|
Lower limb traction + External brace fixation
|
K
|
F
|
8.8y
|
L
|
II
|
Iliosciatic
branch
|
PSD/SIJD
|
ORIF of L sacroiliac joint and symphysis pubis
|
L
|
F
|
7.8y
|
R
|
II
|
Iliopubic branch
|
No
|
External brace fixation
|
M
|
M
|
5.4y
|
R
|
II
|
ischiopubicbranch
|
No
|
External brace fixation
|
N
|
M
|
7.9y
|
L
|
VI
|
Suprapubic branch
|
No
|
Open reduction and external stent fixation + amputation
|
O
|
M
|
9.8y
|
L
|
IV
|
ischiopubicbranch
|
SIJD
|
External brace fixation + Open reduction and external stent fixation + amputation of pelvic fracture
|
ORIF, open reduction and internal fixation; PSD, Pubic Symphysis Diastasis; SIJD, Sacroiliac Joint Dislocation; L, left; R, right; M, male; F, female; |
Table 2
fallow-up of 12 children with Triradiate cartilage injury.
case
|
Follow-up(mo)
|
Bone bridge
|
Premature closure
|
Acetabular
dysplasia
|
Femoral head subluxation
|
HHS
|
AI(°)(L/R)
|
D/W(L/R)
|
AHI(L/R)
|
A
|
17
|
yes
|
yes
|
no
|
no
|
excellet
|
16/10
|
0.324/0.38
|
1/1
|
B
|
66
|
yes
|
no
|
no
|
no
|
excellet
|
8/22
|
0.359/0.319
|
0.93/0.96
|
C
|
77
|
yes
|
no
|
yes
|
yes
|
excellet
|
19/12
|
0.3/0.216
|
0.856/0.695
|
D
|
32
|
yes
|
no
|
no
|
no
|
excellet
|
27/25
|
0.266/0.288
|
0.795/0.81
|
E
|
56
|
no
|
no
|
yes
|
no
|
good
|
15/20
|
0.281/0.247
|
1/1
|
F
|
94
|
no
|
no
|
no
|
no
|
excellet
|
21/21
|
0.286/0.288
|
1/1
|
G
|
71
|
yes
|
yes
|
yes
|
yes
|
good
|
27/21
|
0.214/0.26
|
0.62/0.844
|
H
|
34
|
yes
|
yes
|
no
|
yes
|
excellet
|
23/13
|
0.336/0.294
|
0.64/1
|
I
|
80
|
no
|
no
|
no
|
no
|
excellet
|
24/19
|
0.323/0.332
|
1/1
|
J
|
78
|
yes
|
yes
|
no
|
yes
|
good
|
17/19
|
0.3/0.26*
|
0.77/0.67
|
K
|
80
|
yes
|
yes
|
no
|
no
|
good
|
8/18
|
0.344/0.327
|
0.871/0.755
|
L
|
36
|
no
|
no
|
no
|
no
|
excellet
|
22/14
|
0.306/0.313
|
1/1
|
AI, Acetabular Index; D/W, the Depth-to-Width ratio; AHI, Acetabular Index; |
Typical cases
Case 1 (patient A)
A 6-year-old girl suffered a pelvic fracture after being hit by a car. CT examination showed multiple fractures of the pelvis, bilateral acetabular fractures, separation of the pubic symphysis, and sacral fractures. Triradiate cartilage on the right is a type I injury, and the left is type II injury(Fig. 2A). Closed reduction and external orthofix fixation were performed after the vital signs were stable(Fig. 2B). Two months after the operation, the pelvis gradually bears weight. Follow-up 17 months after the operation, the child had mild claudication, no hip joint pain, and the HHS evaluation was excellent. X-rays of the pelvis showed that the pelvis was slightly tilted and the triradiate cartilage was partially closed, although the acetabulum and femoral head contained a good relationship so far (Fig. 2C), the dysplasia of the aceetabulum should be closely observed in the future.
Case 2 (patient C)
A 1.4-year-old boy was hit by a car, resulting in a fractured pelvis, a fractured femur, and an abdominal injury. X-ray and CT examination of the pelvis revealed fractures of the upper and lower branches of the right pubis and the right ischia, noting the formation of a giant hematoma immediately adjacent to the medial Y-cartilage at the fracture of the superior ramus of the pubis(Fig. 3A-B). Treatment includes bed rest, brace fixation of the lower limbs and pelvis. Five months later, the X-ray showed the formation of a bone bridge across the medial edge of the triradiate cartilage at the hematoma site(Fig. 3C). one year later, the original bone bridge was found to be broken(Fig. 3D). We believe that the fracture of the bone bridge will not further affect the development of the acetabulum, so we choose to continue conservative treatment. Seven years later, the child had mild pain in the right hip, no claudication, and an excellent HHS score. An X-ray showed that the bone bridge was broken, the inner wall of the right acetabulum became thick, the acetabulum became shallow, and the femoral head shifted to the outside(AI 12°, D/W 0.216, AHI 0.683)(Fig. 3E).
Case 3 (patient D)
A 3-year-old girl was crushed by a car and caused a pelvic fracture involving bilateral suprapubic ramus, left inferior pubic ramus, and bilateral ischial ramus fractures, and a fracture of the left femur. CT examination did not show Y-type cartilage damage(Fig. 4A-B). After the essential condition is stable, the left femur was performed ORIF and pelvis was performed external fixation. An X-ray of the pelvis in 4 months after the operation showed the formation of small bone bridges at the right triradiate cartilage and (Fig. 4C). Eleven months after the operation, the X-ray showed that the bone bridge broke spontaneously(Fig. 4D). At the latest follow-up, the child had no pain and claudication in the hip, and the HHS score was excellent. X-rays showed that the acetabulum is well developed(Fig. 4E).