Eur J Orthop Surg Traumatol DOI 10.1007/s00590-015-1614-5
ORIGINAL ARTICLE • KNEE - ARTHROPLASTY
The distinct prediction standards for radiological assessments associated with soft tissue injuries in the acute tibial plateau fracture Jun Wang1,2 • Jie Wei1 • Manyi Wang1
Received: 15 October 2014 / Accepted: 3 February 2015 Springer-Verlag France 2015
Abstract The goal of this study was to assess the incidence of soft tissue injury in the tibial plateau fracture by magnetic resonance image (MRI) and reveal the relationship between the articular widening/depression and the risk of meniscus and ligament disorder. A total of 54 patients with tibial plateau fracture were indicated for operative intervention. Soft tissue injuries were assessed by MRI. Meniscus, anterior/posterior cruciate ligaments and medial/ lateral collateral ligaments injuries on MRI were evaluated. The articular widening/depression was measured in picture archiving and communication systems. Schatzker classification of fracture types was not significantly associated with soft tissue injuries. The rates of soft tissue injury in types IV and II (respectively, 85.7 and 74.1 %) were higher than those in other types. The meniscus injury was the most common soft tissue damage, and the incidence of meniscus injury was 55.6 %. When LPDCT and LPWCT were, respectively, about 7.6 mm and 10.1 mm and LPDX-ray and LPWX-ray, respectively, 5.6 and 7.4 mm, more attention should be paid on the collateral and cruciate ligament injuries in types I, II and III. Furthermore, when LPWCT and LPWX-ray were, respectively, about 10.3 and 8.6 mm, the collateral and cruciate ligaments were susceptible to injury in types IV and V. In conclusion, tibial plateau fracture can
& Manyi Wang [email protected] Jun Wang [email protected] 1
Traumatology Department, Beijing Jishuitan Hospital, No. 31 East Street of Xin Jie Kou, Beijing 100035, People’s Republic of China
2
Medical Center Tsinghua University, No. 30 Shuangqing Rd, Haidian District, Beijing 100084, People’s Republic of China
occur high morbidity of soft tissue injury, including meniscus and ligament disorder. X-ray and CT scan had different predicting standards for soft tissue injury, and the articular widening/depression in the tibial plateau was associated with meniscus and ligament injuries. Keywords Tibial plateau fracture Soft tissue Radiological assessment Articular depression/widening Abbreviation MDCT Multidetector computed tomography LPW Lateral plateau widening LPD Lateral plateau depression MRI Magnetic resonance imaging ACL/PCL Anterior/posterior cruciate ligament MCL/LCL Medial/lateral collateral ligament
Introduction Tibial plateau fracture is among the most challenging of intra-articular fractures to treat. They are commonly classified by the Schatzker system, which is based on the appearance on the anteroposterior radiograph [1, 2]. It has been reported that tibial plateau fracture is accompanied with the meniscus and ligament disorders and associated soft tissue lesions may influence the knee stability [3–5]. Although the effect of primary treatment of concomitant ligament is unclear, stabilizing the injured soft tissue structures with tibial plateau fracture may have a significant effect on postoperative morbidity and functional recovery. Thus, the preoperative diagnosis of related soft tissue injuries in the acute tibial plateau fracture is significant.
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It has been reported that soft tissue injury occurs more frequently with increasing bony displacement of the tibial plateau [6, 7]. Spiro et al. [8] reported that articular depression was a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture and enhancement of articular depression by 9.0 mm increased the absolute number of soft tissue injuries. Durakbasa et al. [6] reported that a plain anteroposterior radiograph depicting a lateral plateau depression ]14 mm and/or a lateral plateau widening ]10 mm was associated with a significantly high risk of meniscal injury in Schatzker type II tibial plateau fracture. Thus, our study aimed to assess the incidence of soft tissue injury in the tibial plateau fracture by MR image and reveal the relationship between the assessment of articular widening/depression by different radiological methods and the risk of soft tissue disorder.
Materials and methods A prospective study of patient files as well as imaging evaluation was conducted at the Traumatology Department. A total of 54 patients with acute tibial plateau fracture were admitted to the department between October 2013 and March 2014 (35 males and 19 females). Average patient age was 48.3 ± 11.2 with a range from 27 to 69 years. Plain radiographs, multidetector computed tomography (MDCT) scans and MR images were obtained for analysis of each patient. MDCT was indicated for detailed evaluation of the fracture morphology and determination of Schatzker classification. MRI provided information with regard to specific soft tissue injuries (Figs. 1, 2). The mechanism of injury was motor vehicle accident in 22 patients, fall from height in 12 and fall onto the ground in 20. The patients who had a history of previously known knee pain or dysfunction of knee were excluded. All patients were operated with open reduction and internal fixation, and direct visualization and evaluation of the meniscus and ligament injuries were obtained during the operation. Radiographic measurements All fractures were classified according to the Schatzker classification [2]. The Schatzker classification divides tibial plateau fractures into six types: split fracture of the lateral plateau without depression (I), split depression fracture of the lateral plateau (II), pure depression fracture of the lateral or central plateau (III), medial plateau fracture (IV), bicondylar plateau fracture (V) and plateau fracture with meta-diaphyseal discontinuity (VI). However, in our
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trauma center, the type VI fracture was operated with the stainless steel external fixation in the emergency, and they cannot be examined by the MR image. Thus, we excluded the type VI tibial plateau fractures. The plain AP radiographs and coronal images of MDCT (16-slice multidetector computed tomography, Toshiba) were evaluated to measure following parameters: the lateral plateau depression (LPD) and the lateral plateau widening (LPW) for low-energy associated fracture (types I, II and III) and lateral plateau depression (LPD) for highenergy associated fracture (types IV and V) [6]. The LPD was calculated in millimeters by the difference between a reference line drawn from the extension of the medial plateau parallel to the joint line (b) and a line parallel to the reference line drawn from the maximum lateral plateau depression (b0 ). The LPW was calculated in millimeters between a tangential line to the lateral femoral epicondyle (a0 ) which was perpendicular to b and a line drawn from the most lateral part of the lateral tibial plateau (a) which was parallel to a0 . All measurements were made by three doctors, and the mean values were used for the final analysis. MR image acquisition For MRI evaluation, a 1.5 T (Siemens) was used to examine the soft tissue disorder associated with tibial plateau fracture. All patients were placed in the supine position. After removing any splint, the knee was scanned with a dedicated receive coil (SENSE-knee-8, Philips, Best, The Netherlands). MRI provided detailed change with regard to specific soft tissue injuries. MRIs were evaluated by the same experienced musculoskeletal radiologist for crucial and collateral ligament injury and meniscal tears. Statistical methods Statistical analysis was performed with the use of a v2 test for discrete variables (Tables 1, 3, 4); Comparisons of the two data sets were analyzed by t tests (Tables 5, 6). Effect of depression and widening of tibial plateau on the probability of meniscus and ligament injuries was estimated by logistic regression. Descriptive statistics are reported as percentage or mean ± SD (SD, standard deviation). For all tests, significance was considered P \ 0.05.
Results Schatzker classification identified 3 type I (split), 27 type II (split and depression), 3 type III (depression), 14 type IV (medial plateau) and 7 type V (bicondylar) fractures. Table 1 summarizes the incidences of associated soft tissue injuries for each type of fracture. Out of 54 patients, 41
Eur J Orthop Surg Traumatol Fig. 1 a–c Case 1, 55-year-old man presented with a right tibial plateau fracture. a Anteroposterior radiograph of the injured knee (LPDX-ray, 5.62 mm; LPWX-ray, 4.81 mm); b CT demonstrated a Schatzker type II fracture with maximum articular depression and widening (LPDCT, 7.88 mm; LPWCT, 5.92 mm); c MRI revealed lateral meniscus tears. d–f Case 2, 46-year-old man presented with a left tibial plateau fracture. d Anteroposterior radiograph of the injured knee (LPDX-ray, 0.65 mm; LPWX-ray, 0.99 mm); b CT scan (LPDCT, 1.1 mm; LPWCT, 1.23 mm); f MRI revealed no meniscus and ligament injury
with tibial plateau fractures (75.9 %) had some associated soft tissue injury in our study. For the details, we found that the fracture of Schatzker type was not significantly associated with soft tissue injuries (P [ 0.05). However, the soft tissue injury rates of types IV and II (respectively, 85.7 and 74.1 %) were higher than those of other types. For ACL injury, the rate of type IV was statistically higher than that of other types (P \ 0.05) (Table 1). Table 1 lists the incidence of meniscal injury for each fracture type, and Table 2 summarizes the form of meniscal injury and its incidence. The meniscus injury was the most common soft tissue damage associated with the Schatzker types, and the incidence of meniscus injury was 55.6 %. The main form of meniscus injury was the peripheral tear (lateral meniscus, 25.9 %; medial meniscus, 11.1 %) (Table 2). The incidence of PCL tear was lower than that of other soft tissue injury, and PCL tear was mainly caused by the high-energy force inducing the tibial stirring to the rear. Thirteen patients had multiple soft tissue injuries of the 54 occurrences of fracture in this study. There was no significant difference for the multiple soft tissue injuries among the fractures (P [ 0.05). The result illustrated that the multiple soft tissue injuries were not associated with the Schatzker type. However, the frequency of multiple lesions was higher in types II, IV and V (respectively, 25.9, 28.6 and 28.6 %) than that in types I and III
(Table 3). Furthermore, we calculated the frequency of multiple lesions between the low- and high-energy fractures (LEF/HEF). LEF and HEF groups, respectively, included types I, II and III and types IV and V. The frequency of multiple lesions in the HEF group was higher than that in the LEF group, but not statistically (P [ 0.05) (Table 4). Statistical analyses were performed to determine whether the amount of articular depression and plateau widening was associated with soft tissue injuries including the meniscus, collateral ligament and cruciate ligament injuries. Table 5 shows that for the level of tibial plateau depression and widening resulting from the low-energy trauma, there was significant difference between the injured and non-injured ligament including the collateral and cruciate ligaments (P \ 0.05). It illustrated that patients with a large amount of depression and widening tibial plateau were vulnerable to collateral and cruciate ligament injuries. Meanwhile, LPD and LPW of injured meniscus were higher than those of non-injured, but not significantly (P [ 0.05). Furthermore, LPD and LPW of MDCT scan were larger than those of X-ray. Thus, when LPDCT and LPWCT were, respectively, 7.6 and 10.1 mm and LPDX-ray and LPWX-ray, respectively, 5.6 and 7.4 mm, more attention should be paid on the collateral and cruciate ligament injuries in types I, II and III.
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Fig. 2 a–d Case 1, 48-year-old man presented with a left tibial plateau fracture, Schatzker IV fracture. a Anteroposterior radiograph of the injured knee (LPWX-ray, 8.56 mm); b CT demonstrated a Schatzker type IV fracture with maximum tibial plateau widening (LPWCT, 9.87 mm); c, d MRI revealed anterior cruciate and medial
Table 1 Data from 54 patients: Schatzker classification of fracture types and associated soft tissue injuries
collateral ligament injury, showing different intensity in the MR image. e–h Case 2, 48-year-old man presented with a right tibial plateau fracture, resulting from fall injury. e Anteroposterior radiograph of the injured knee (LPWX-ray, 2.43 mm); f CT scan (LPWCT, 3.44 mm); g, h MRI revealed no meniscus and ligament injury
Type
Meniscus
ACL
PCL (%)
MCL (%)
LCL (%)
I (n = 3)
1 (33.3 %)
0 (0)
0 (0)
0 (0)
0 (0)
II (n = 27)
18 (66.7 %)
1 (3.7 %)
1 (3.7 %)
0 (0)
3 (11.1 %)
III (n = 3)
1 (33.3 %)
0 (0)
0 (0)
0 (0)
0 (0)
IV (n = 14)
6 (42.9 %)
7 (50 %)
0 (0)
3 (21.4 %)
1 (7.1 %)
V (n = 7)
4 (57.1 %)
1 (14.3 %)
1 (14.3 %)
2 (28.6 %)
1 (14.3 %)
Total (n = 54)
30 (55.6 %)
9 (16.7 %)
2 (3.7 %)
5 (9.3 %)
5 (9.3 %)
P value
NS
0.003
NS
NS
NS
ACL anterior cruciate ligament, PCL posterior cruciate ligament, MCL medial collateral ligament, LCL lateral collateral ligament, NS not significantly
Table 6 shows that a large amount of widening tibial plateau was prone to cause the collateral and cruciate ligament injuries for patients with high-energy type IV and V fractures. For LPWCT, there was significant difference between injured and non-injured collateral and cruciate ligaments in the type IV and V fractures (P \ 0.05). However, the result showed that LPWCT and LPWX-ray were not related to the meniscus injury. LPWCT and LPWX-ray of patients with non-injured meniscus were smaller than those of ones with injured meniscus, but not statistically (P [ 0.05). Furthermore, for LPWX-ray, there was significant difference between injured and non-injured collateral ligament in the type IV and V fractures
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(P \ 0.05), but not significantly for the cruciate ligament injury (P [ 0.05). Thus, when LPWCT and LPWX-ray were, respectively, 10.3 and 8.6 mm, the collateral and cruciate ligaments were susceptible to injury in types IV and V. Further logistic regression was performed to determine whether the amount of LPW and LPD correlates with the incidence and number of soft tissue injuries in tibial plateau fractures. Table 7 shows that, for the tibial plateau fracture caused by low-energy trauma, logistic regression results showed a significant impact of increasing LPWCT/X-ray and LPDCT on the incidence of collateral ligament injury (P \ 0.05). Meanwhile, LPWCT/X-ray and LPDCT/X-ray were associated with the cruciate ligament injury (P \ 0.05).
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Table 8 shows a statistical correlation existed between LPWCT/X-ray and collateral ligament injury (P \ 0.05). LPWCT was significantly related to the cruciate ligament injury. However, LPW and LPD were not related to the meniscus injury in the patients with tibial plateau fracture caused by low- or high-energy trauma (P [ 0.05).
Table 2 Detail of soft tissue injury incidence Associated soft tissue injuries (n = 54)
Number of injuries (%)
Menisci Lateral meniscus peripheral tear
14 (25.9 %)
Lateral meniscus horn tear
12 (22.2 %)
Medial meniscus peripheral tear
6 (11.1 %)
Medial meniscus horn tear
1 (1.9 %)
Discussion
Collateral ligaments LCL tear
5 (9.3 %)
MCL tear
5 (9.3 %)
Tibial plateau fracture is one of the most complex intraarticular injuries in trauma surgery that are associated with a variety of fracture patterns, including lateral and medial plateau split, articular depression, comminution and soft tissue disorders including ligament and meniscus injuries
Cruciate ligaments ACL tear
14 (25.9 %)
PCL tear
2 (3.7 %)
Table 3 Relationship between fracture type and multiple soft tissue injuries
Type
Associated multiple soft tissue injuries 2 Lesions
Frequency of multiple lesions
3 Lesions
I (n = 3)
0
0
0 % (0/2)
II (n = 27)
6
1
25.9 % (7/27)
III (n = 3)
0
0
0 % (0/3)
IV (n = 14)
3
1
28.6 % (4/14)
V (n = 7)
2
0
28.6 % (2/7)
P value
NS
Total (n = 54)
11
2
24.1 % (13/54)
NS not significantly
Table 4 Relationship between low-/high-energy associated fracture type and multiple soft tissue injuries
Type
Associated multiple soft tissue injuries
Frequency of multiple lesions
2 Lesions
3 Lesions
LEF
6
1
21.2 % (7/33)
HEF
5
1
28.6 % (6/21)
P value
NS
LEF low-energy fracture, HEF high-energy fracture, NS not significantly
Table 5 Depression and widening of tibial plateau resulting from low-energy trauma for soft tissue injury
Meniscus No
Yes
Collateral ligament
Cruciate ligament
No
No
Yes
Yes
Associated soft tissue injury 2.2 ± 2 1 3.5 ± 1.7 LPDX-ray
2.6 ± 1.7
5.6 ± 1.5*
2.5 ± 1.8
5.0 ± 1.4*
LPDCT
2.8 ± 2.7
4.2 ± 1.9
3.1 ± 1.8
7.6 ± 2.0*
3.1 ± 2.2
5.9 ± 1.3*
LPWX-ray
2.9 ± 2.6
4.0 ± 1.8
3.1 ± 1.5
7.4 ± 2.7*
3.0 ± 1.8
6.3 ± 1.4*
LPWCT
3.7 ± 3.2
5.1 ± 2.4
3.8 ± 1.6
10.1 ± 3.4*
3.7 ± 2.1
8.2 ± 2.7*
LPWX-ray and LPWCT, the lateral plateau widening by X-ray and MDCT scan; LPDX-ray and LPDCT, the lateral plateau depression by X-ray and MDCT scan * P \ 0.05, compared with non-injured soft tissue
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Eur J Orthop Surg Traumatol Table 6 Widening of tibial plateau resulting from highenergy trauma for soft tissue injury
Meniscus No
Collateral ligament
Cruciate ligament
Yes
No
No
Yes
Yes
Associated soft tissue injury LPWX-ray
7.2 ± 1.8
6.6 ± 3.4
5.1 ± 2.0
8.6 ± 2.6*
5.4 ± 2.4
7.4 ± 2.8
LPWCT
8.4 ± 1.8
8.1 ± 4.7
6.1 ± 2.1
10.3 ± 4.3*
6.2 ± 2.4
9.3 ± 4.2*
LPWX-ray and LPWCT, the lateral plateau widening by X-ray and MDCT scan * P \ 0.05, compared with non-injured soft tissue
Table 7 Logistic regression analysis for the correlation between LPWCT/X-ray/LPDCT/X-ray and soft tissue injuries associated with tibial plateau fracture caused by low-energy trauma
Associated soft tissue injuries
Parameters
OR
95 % CI
P value
Meniscus
LPDCT
1.37
0.79–2.40
0.27
LPDX-ray
1.45
0.78–2.69
0.24
LPWCT
1.02
0.63–1.65
0.92
LPWX-ray
1.04
0.59–1.84
0.902
LPDCT
1.13
0.44–2.92
0.015
LPDX-ray
1.13
0.42–3.03
0.063
LPWCT
1.51
0.78–2.94
0.002
LPWX-ray
1.49
0.69–3.23
0.019
LPDCT LPDX-ray
1.14 1.50
0.68–3.25 0.78–3.94
0.002 0.001
LPWCT
1.27
0.58–2.94
0.003
LPWX-ray
1.27
0.48–2.74
0.003
Collateral ligament
Cruciate ligament
Table 8 Logistic regression analysis for the correlation between LPWCT/X-ray and soft tissue injuries associated with tibial plateau fracture caused by high-energy trauma
Associated soft tissue injuries Meniscus Collateral ligament Cruciate ligament
[2, 3, 9, 10]. The adequate treatment is challenging and has a significant impact on functional outcome. Non-anatomic reduction in the joint surface, malalignment and associated soft tissue lesions may promote the post-traumatic arthritis in these patients [6, 11, 12]. The use of magnetic resonance imaging in diagnosing soft tissue pathology in the knee disorder has been well described [7, 9, 13]. MRI provides sufficient information with regard to specific ligamentous and meniscal injuries. Gardner et al. [9] evaluated 103 operative tibial plateau fractures by the magnetic resonance imaging analysis and reported that 99 % of cases showed evidence of derangement of soft tissue structure around the knee, 77 % complete cruciate or collateral rupture, 74 % lateral meniscus tears, 83 % lateral capsular separations and 44 % medial meniscal tears. Bennett et al. [14] assessed 30 tibial plateau fractures by the pre- and postfixation stress testing and
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Parameters
Odds ratio
95 % CI
P value
LPWCT
1.41
0.47–4.27
0.428
LPWX-ray
0.74
0.2–2.78
0.514
LPWCT
1.48
0.08–2.83
0.01
LPWX-ray
5.76
0.47–4.9
0.004
LPWCT
1.18
0.98–1.83
0.044
LPWX-ray
1.28
0.78–1.83
0.086
diagnostic arthroscopy and illustrated that there was a 56 % frequency of associated soft tissue injuries, including 20 % medial collateral ligament injury, 3 % lateral collateral ligament injury and 20 % meniscus tears. By the arthroscopic testing, Abdel-Hamid et al. [10] reported that the frequency of soft tissue injury in their study was 71 %, 57 % meniscus injury, 25 and 5 %, respectively, for the anterior and posterior cruciate ligament and 3 and 3 %, respectively, for the medial and lateral collateral ligament. In our study, the results showed 55.6 % meniscus injury, 16.7 % ACL injury, 3.7 % PCL injury, 9.3 % MCL injury and 9.3 % LCL injury. The incidence of meniscus injury (55.6 %, 30/54) was higher than that of other soft tissue injury form. Furthermore, most of ACL injury occurred in the type IV and there was significant difference between the five types. These results were similar to the previous studies [8, 9, 14].
Eur J Orthop Surg Traumatol
In our trauma center, patients with type VI tibial plateau fracture are operated with stainless steel external fixator in the emergency, and MRI evaluation is not used for them. Thus, only patients with Schatzker I–V tibial plateau fracture were included in our study. It has been reported that articular depression was a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture. They demonstrated a significant impact of increasing tibial plateau fracture depression on the incidence of meniscus lateralis tears. However, our results showed that the meniscal injury was not significantly associated with articular depression and widening. Due to the axial load and varus/valgus force, less plateau depression or widening probably results in the meniscus peripheral tear, accounting for 37 % (20/54) in our study [1, 2, 6, 12]. Thus, the correlation between the articular depression/ widening and meniscal injury was not significant in this study. Furthermore, the present study revealed that meniscus injury was the main type of soft tissue injury in the patients with acute tibial plateau fracture. It has been reported that the anterior cruciate ligament injury is common in the acute type IV tibial plateau, and the results of our study also support this phenomenon [6, 8, 9, 14]. A debilitating outcome of ACL injury is severe knee instability, which can lead to osteoarthritis [15–20]. The ACL is usually surgically reconstructed to restore knee stability [21–23]. The ACL is known to be a restraint against anterior tibial loads by limiting anterior tibial translations [21, 24, 25]. The Schatzker type IV fracture also results from the complex varus/valgus violence and axial load. The previous study illustrated that excessive axial compression load would cause relative displacement and rotation of the tibial with respect to the femur and result in isolated injury to the ACL when the knee was fixed to 60, 90 and 120 [26]. This could explain the phenomenon that type IV fracture is accompanied by the ACL injury. The percentage of soft tissue injuries in type IV is the highest among the all types in our study. This type is common in the high-energy tibial plateau fractures. Meanwhile, in this type, the medial plateau is either split off as a wedge fragment or depressed and comminuted [2]. Some authors proposed that type IV could also be called fracture-dislocation type, which is characterized of lateral column dislocation, and also associated with soft tissue injuries [27]. Schatzker et al. [2] reported that cruciate ligament disruption frequently occurs in association with medial condylar fracture. In the literature, it has been reported that types II and V were also related to the incidence of soft tissue injuries due to the articular depression and dislocation [6–9, 27]. Our result was similar to the studies in the literature. Based on the trauma violence, the Schatzker classification of tibial plateau fracture could be divided into two categories, including types I, II and III for
low-energy trauma and types IV, V and VI for high-energy trauma [28]. Fractures caused by the high-energy trauma are theoretically coupled with multiple soft tissue injuries, and some reports support this idea. Abdel-Hamid et al. [10] reported that the rates of multiple soft tissue injuries in the Schatzker types IV, V and VI were, respectively, 32, 25 and 25 % by the arthroscopic evaluation. In our study, the rates of multiple soft tissue injuries in the low- and highenergy fracture were, respectively, 21.2 and 28.6 %. Furthermore, the multiple soft tissue injuries were common in the type II. This may be related to the case of type VI missing and a small number of cases. The parameters tested by different radiological methods differed greater in our study. It has been reported that a plain anteroposterior radiograph depicting a lateral plateau depression ]14 mm and/or a lateral plateau widening ]10 mm was associated with a significantly increased risk of meniscal injury in Schatzker type II tibial plateau fractures [6]. Many investigators have found that surgical plans based on plain radiographic findings were modified after preoperative computed tomography or magnetic resonance imaging [13, 29]. Schatzker II fractures with depression or widening approaching 5 mm deserve heightened vigilance in diagnosing the soft tissue injuries [7]. In our study, we found that for low-energy trauma, when LPDX-ray ] 5 mm, LPWX-ray ] 6 mm, LPDCT ] 6 mm and/or LPWCT ] 8 mm, we should be aware of the associated soft tissue injuries. Meanwhile, for high-energy trauma, when LPWX-ray ] 7 mm and/or LPWCT ] 9 mm, more attention should be paid on the accompanied soft tissue injuries. The fracture of Schatzker type IV is mainly characterized by the fact that the medial plateau either is split off as a wedge fragment or depressed and comminuted. The Schatzker V fracture line often has the appearance of an inverted Y, not mainly articular depression. Thus, the articular depression was not assessed for patients with type IV and V fractures in our study, based on the characteristics of the two types. There are some limitations for our study. Firstly, the cases were not included the Schatzker VI, and this may exert greater influence on the results. Secondly, although all measurements were made by three authors and the mean values were used for the final analysis, subjective deviation still existed in our study. Furthermore, meniscus injury could be easily observed during the operation, but the cruciate and collateral ligament could not visualized in the operation, influencing by the surgical approach, extent of damage and treatment plan. Thus, we could not make a verification for MRI results. From this perspective, arthroscopic evaluation is better than MRI assessment, but the former one is invasive. In addition, there is a large disadvantage of our study. Namely, due to the less cases, we did not distinguish different injury forms of meniscus
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and ligament, such as tear injury and partial/complete ruptures in our study. Our further study is processing. More cases will be included, and more exact details will be emerged in the future. In conclusion, acute tibial plateau fracture is often associated with the soft tissue injuries, and different radiological methods, such as plain and CT scan, have distinct prediction standards for ligament injuries accompanied with tibial plateau fracture. For low-energy trauma, when LPDX-ray ] 5 mm, LPWX-ray ] 6 mm, LPDCT ] 6 mm and/or LPWCT ] 8 mm, we should be aware of the associated soft tissue injuries. Meanwhile, for high-energy trauma, when LPWX-ray ] 7 mm and/or LPWCT ] 9 mm, more attention should be paid on the accompanied soft tissue injuries. Thus, a plain anteroposterior radiograph and MDCT scan could predict the occurence of soft tissue disorders with tibial plateau fracture.
Conflict of interest of interest.
The authors declare that there are no conflicts
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10. Abdel-Hamid MZ, Chang CH, Chan YS, Lo YP, Huang JW, Hsu KY, Wang CJ (2006) Arthroscopic evaluation of soft tissue injuries in tibial plateau fractures: retrospective analysis of 98 cases. Arthroscopy 22:669–675 11. Sun H, Luo C-F, Yang G, Shi H-P, Zeng B-F (2012) Anatomical evaluation of the modified posterolateral approach for posterolateral tibial plateau fracture. Eur J Orthop Surg Traumatol 23:809–818 12. Tscherne H, Lobenhoffer P (1993) Tibial plateau fractures. Management and expected results. Clin Orthop Relat Res 292:87–100 13. Mui LW, Engelsohn E, Umans H (2007) Comparison of CT and MRI in patients with tibial plateau fracture: can CT findings predict ligament tear or meniscal injury? Skeletal Radiol 36:145–151 14. Bennett WF, Browner B (1994) Tibial plateau fracture: a study of associated soft tissue injuries. J Orthop Trauma 8:183–188 15. Solomon LB, Boopalan PR, Chakrabarty A, Callary SA (2014) Can tibial plateau fractures be reduced and stabilised through an angiosome-sparing antero-lateral approach? Injury 45:766–774 16. Berber R, Lewis CP, Copas D, Forward DP, Moran CG (2014) Postero-medial approach for complex tibial plateau injuries with a postero-medial or postero-lateral shear fragment. Injury 45:757–765 17. Lasanianos NG, Garnavos C, Magnisalis E, Kourkoulis S, Babis GC (2013) A comparative biomechanical study for complex tibial plateau fractures: nailing and compression bolts versus modern and traditional plating. Injury 44:1333–1339 18. Weaver MJ, Harris MB, Strom AC, Smith RM, Lhowe D, Zurakowski D, Vrahas MS (2012) Fracture pattern and fixation type related to loss of reduction in bicondylar tibial plateau fractures. Injury 43:864–869 19. Cift H, Cetik O, Kalaycioglu B, Dirikoglu MH, Ozkan K, Eksioglu F (2010) Biomechanical comparison of plate-screw and screw fixation in medial tibial plateau fractures (Schatzker 4). A model study. Orthop Traumatol Surg Res 96:263–267 20. Mehin R, O’Brien P, Broekhuyse H, Blachut P, Guy P (2012) Endstage arthritis following tibia plateau fractures: average 10-year follow-up. Can J Surg 55:87–94 21. Lebel B, Hulet C, Galaud B, Burdin G, Locker B, Vielpeau C (2008) Arthroscopic reconstruction of the anterior cruciate ligament using bone-patellar tendon-bone autograft: a minimum 10-year follow-up. Am J Sports Med 36:1275–1282 22. Khoshnoodi P, Tehranzadeh AD, Dunn JM, Tehranzadeh J (2014) Semimembranosus tendon avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament tear and capsular rupture. Skeletal Radiol 43:239–242 23. Yoon JR, Jeong HI, Wang JH, Jang KM, Yang JH (2013) Tibial plateau fracture after single bundle anterior cruciate ligament reconstruction using post-tie washer-screw fixation. J Orthop Sci 20:205–208 24. Gabriel MT, Wong EK, Woo SL, Yagi M, Debski RE (2004) Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loads. J Orthop Res 22:85–89 25. Fu FH, Karlsson J (2010) A long journey to be anatomic. Knee Surgery Sports Traumatol Arthrosc 18:1151–1153 26. Meyer EG, Haut RC (2005) Excessive compression of the human tibio-femoral joint causes ACL rupture. J Biomech 38:2311–2316 27. Stannard JP, Lopez R, Volgas D (2010) Soft tissue injury of the knee after tibial plateau fractures. J Knee Surg 23:187–192 28. Agnew S (1999) Tibial plateau fractures. Oper Tech Orthop 9:197–205 29. Markhardt BK, Gross JM, Monu J (2009) Schatzker classification of tibial plateau fractures: use of CT and MR imaging improves assessment. Radiographics 29:585–597
ORIGINAL ARTICLE • KNEE - ARTHROPLASTY
The distinct prediction standards for radiological assessments associated with soft tissue injuries in the acute tibial plateau fracture Jun Wang1,2 • Jie Wei1 • Manyi Wang1
Received: 15 October 2014 / Accepted: 3 February 2015 Springer-Verlag France 2015
Abstract The goal of this study was to assess the incidence of soft tissue injury in the tibial plateau fracture by magnetic resonance image (MRI) and reveal the relationship between the articular widening/depression and the risk of meniscus and ligament disorder. A total of 54 patients with tibial plateau fracture were indicated for operative intervention. Soft tissue injuries were assessed by MRI. Meniscus, anterior/posterior cruciate ligaments and medial/ lateral collateral ligaments injuries on MRI were evaluated. The articular widening/depression was measured in picture archiving and communication systems. Schatzker classification of fracture types was not significantly associated with soft tissue injuries. The rates of soft tissue injury in types IV and II (respectively, 85.7 and 74.1 %) were higher than those in other types. The meniscus injury was the most common soft tissue damage, and the incidence of meniscus injury was 55.6 %. When LPDCT and LPWCT were, respectively, about 7.6 mm and 10.1 mm and LPDX-ray and LPWX-ray, respectively, 5.6 and 7.4 mm, more attention should be paid on the collateral and cruciate ligament injuries in types I, II and III. Furthermore, when LPWCT and LPWX-ray were, respectively, about 10.3 and 8.6 mm, the collateral and cruciate ligaments were susceptible to injury in types IV and V. In conclusion, tibial plateau fracture can
& Manyi Wang [email protected] Jun Wang [email protected] 1
Traumatology Department, Beijing Jishuitan Hospital, No. 31 East Street of Xin Jie Kou, Beijing 100035, People’s Republic of China
2
Medical Center Tsinghua University, No. 30 Shuangqing Rd, Haidian District, Beijing 100084, People’s Republic of China
occur high morbidity of soft tissue injury, including meniscus and ligament disorder. X-ray and CT scan had different predicting standards for soft tissue injury, and the articular widening/depression in the tibial plateau was associated with meniscus and ligament injuries. Keywords Tibial plateau fracture Soft tissue Radiological assessment Articular depression/widening Abbreviation MDCT Multidetector computed tomography LPW Lateral plateau widening LPD Lateral plateau depression MRI Magnetic resonance imaging ACL/PCL Anterior/posterior cruciate ligament MCL/LCL Medial/lateral collateral ligament
Introduction Tibial plateau fracture is among the most challenging of intra-articular fractures to treat. They are commonly classified by the Schatzker system, which is based on the appearance on the anteroposterior radiograph [1, 2]. It has been reported that tibial plateau fracture is accompanied with the meniscus and ligament disorders and associated soft tissue lesions may influence the knee stability [3–5]. Although the effect of primary treatment of concomitant ligament is unclear, stabilizing the injured soft tissue structures with tibial plateau fracture may have a significant effect on postoperative morbidity and functional recovery. Thus, the preoperative diagnosis of related soft tissue injuries in the acute tibial plateau fracture is significant.
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It has been reported that soft tissue injury occurs more frequently with increasing bony displacement of the tibial plateau [6, 7]. Spiro et al. [8] reported that articular depression was a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture and enhancement of articular depression by 9.0 mm increased the absolute number of soft tissue injuries. Durakbasa et al. [6] reported that a plain anteroposterior radiograph depicting a lateral plateau depression ]14 mm and/or a lateral plateau widening ]10 mm was associated with a significantly high risk of meniscal injury in Schatzker type II tibial plateau fracture. Thus, our study aimed to assess the incidence of soft tissue injury in the tibial plateau fracture by MR image and reveal the relationship between the assessment of articular widening/depression by different radiological methods and the risk of soft tissue disorder.
Materials and methods A prospective study of patient files as well as imaging evaluation was conducted at the Traumatology Department. A total of 54 patients with acute tibial plateau fracture were admitted to the department between October 2013 and March 2014 (35 males and 19 females). Average patient age was 48.3 ± 11.2 with a range from 27 to 69 years. Plain radiographs, multidetector computed tomography (MDCT) scans and MR images were obtained for analysis of each patient. MDCT was indicated for detailed evaluation of the fracture morphology and determination of Schatzker classification. MRI provided information with regard to specific soft tissue injuries (Figs. 1, 2). The mechanism of injury was motor vehicle accident in 22 patients, fall from height in 12 and fall onto the ground in 20. The patients who had a history of previously known knee pain or dysfunction of knee were excluded. All patients were operated with open reduction and internal fixation, and direct visualization and evaluation of the meniscus and ligament injuries were obtained during the operation. Radiographic measurements All fractures were classified according to the Schatzker classification [2]. The Schatzker classification divides tibial plateau fractures into six types: split fracture of the lateral plateau without depression (I), split depression fracture of the lateral plateau (II), pure depression fracture of the lateral or central plateau (III), medial plateau fracture (IV), bicondylar plateau fracture (V) and plateau fracture with meta-diaphyseal discontinuity (VI). However, in our
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trauma center, the type VI fracture was operated with the stainless steel external fixation in the emergency, and they cannot be examined by the MR image. Thus, we excluded the type VI tibial plateau fractures. The plain AP radiographs and coronal images of MDCT (16-slice multidetector computed tomography, Toshiba) were evaluated to measure following parameters: the lateral plateau depression (LPD) and the lateral plateau widening (LPW) for low-energy associated fracture (types I, II and III) and lateral plateau depression (LPD) for highenergy associated fracture (types IV and V) [6]. The LPD was calculated in millimeters by the difference between a reference line drawn from the extension of the medial plateau parallel to the joint line (b) and a line parallel to the reference line drawn from the maximum lateral plateau depression (b0 ). The LPW was calculated in millimeters between a tangential line to the lateral femoral epicondyle (a0 ) which was perpendicular to b and a line drawn from the most lateral part of the lateral tibial plateau (a) which was parallel to a0 . All measurements were made by three doctors, and the mean values were used for the final analysis. MR image acquisition For MRI evaluation, a 1.5 T (Siemens) was used to examine the soft tissue disorder associated with tibial plateau fracture. All patients were placed in the supine position. After removing any splint, the knee was scanned with a dedicated receive coil (SENSE-knee-8, Philips, Best, The Netherlands). MRI provided detailed change with regard to specific soft tissue injuries. MRIs were evaluated by the same experienced musculoskeletal radiologist for crucial and collateral ligament injury and meniscal tears. Statistical methods Statistical analysis was performed with the use of a v2 test for discrete variables (Tables 1, 3, 4); Comparisons of the two data sets were analyzed by t tests (Tables 5, 6). Effect of depression and widening of tibial plateau on the probability of meniscus and ligament injuries was estimated by logistic regression. Descriptive statistics are reported as percentage or mean ± SD (SD, standard deviation). For all tests, significance was considered P \ 0.05.
Results Schatzker classification identified 3 type I (split), 27 type II (split and depression), 3 type III (depression), 14 type IV (medial plateau) and 7 type V (bicondylar) fractures. Table 1 summarizes the incidences of associated soft tissue injuries for each type of fracture. Out of 54 patients, 41
Eur J Orthop Surg Traumatol Fig. 1 a–c Case 1, 55-year-old man presented with a right tibial plateau fracture. a Anteroposterior radiograph of the injured knee (LPDX-ray, 5.62 mm; LPWX-ray, 4.81 mm); b CT demonstrated a Schatzker type II fracture with maximum articular depression and widening (LPDCT, 7.88 mm; LPWCT, 5.92 mm); c MRI revealed lateral meniscus tears. d–f Case 2, 46-year-old man presented with a left tibial plateau fracture. d Anteroposterior radiograph of the injured knee (LPDX-ray, 0.65 mm; LPWX-ray, 0.99 mm); b CT scan (LPDCT, 1.1 mm; LPWCT, 1.23 mm); f MRI revealed no meniscus and ligament injury
with tibial plateau fractures (75.9 %) had some associated soft tissue injury in our study. For the details, we found that the fracture of Schatzker type was not significantly associated with soft tissue injuries (P [ 0.05). However, the soft tissue injury rates of types IV and II (respectively, 85.7 and 74.1 %) were higher than those of other types. For ACL injury, the rate of type IV was statistically higher than that of other types (P \ 0.05) (Table 1). Table 1 lists the incidence of meniscal injury for each fracture type, and Table 2 summarizes the form of meniscal injury and its incidence. The meniscus injury was the most common soft tissue damage associated with the Schatzker types, and the incidence of meniscus injury was 55.6 %. The main form of meniscus injury was the peripheral tear (lateral meniscus, 25.9 %; medial meniscus, 11.1 %) (Table 2). The incidence of PCL tear was lower than that of other soft tissue injury, and PCL tear was mainly caused by the high-energy force inducing the tibial stirring to the rear. Thirteen patients had multiple soft tissue injuries of the 54 occurrences of fracture in this study. There was no significant difference for the multiple soft tissue injuries among the fractures (P [ 0.05). The result illustrated that the multiple soft tissue injuries were not associated with the Schatzker type. However, the frequency of multiple lesions was higher in types II, IV and V (respectively, 25.9, 28.6 and 28.6 %) than that in types I and III
(Table 3). Furthermore, we calculated the frequency of multiple lesions between the low- and high-energy fractures (LEF/HEF). LEF and HEF groups, respectively, included types I, II and III and types IV and V. The frequency of multiple lesions in the HEF group was higher than that in the LEF group, but not statistically (P [ 0.05) (Table 4). Statistical analyses were performed to determine whether the amount of articular depression and plateau widening was associated with soft tissue injuries including the meniscus, collateral ligament and cruciate ligament injuries. Table 5 shows that for the level of tibial plateau depression and widening resulting from the low-energy trauma, there was significant difference between the injured and non-injured ligament including the collateral and cruciate ligaments (P \ 0.05). It illustrated that patients with a large amount of depression and widening tibial plateau were vulnerable to collateral and cruciate ligament injuries. Meanwhile, LPD and LPW of injured meniscus were higher than those of non-injured, but not significantly (P [ 0.05). Furthermore, LPD and LPW of MDCT scan were larger than those of X-ray. Thus, when LPDCT and LPWCT were, respectively, 7.6 and 10.1 mm and LPDX-ray and LPWX-ray, respectively, 5.6 and 7.4 mm, more attention should be paid on the collateral and cruciate ligament injuries in types I, II and III.
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Fig. 2 a–d Case 1, 48-year-old man presented with a left tibial plateau fracture, Schatzker IV fracture. a Anteroposterior radiograph of the injured knee (LPWX-ray, 8.56 mm); b CT demonstrated a Schatzker type IV fracture with maximum tibial plateau widening (LPWCT, 9.87 mm); c, d MRI revealed anterior cruciate and medial
Table 1 Data from 54 patients: Schatzker classification of fracture types and associated soft tissue injuries
collateral ligament injury, showing different intensity in the MR image. e–h Case 2, 48-year-old man presented with a right tibial plateau fracture, resulting from fall injury. e Anteroposterior radiograph of the injured knee (LPWX-ray, 2.43 mm); f CT scan (LPWCT, 3.44 mm); g, h MRI revealed no meniscus and ligament injury
Type
Meniscus
ACL
PCL (%)
MCL (%)
LCL (%)
I (n = 3)
1 (33.3 %)
0 (0)
0 (0)
0 (0)
0 (0)
II (n = 27)
18 (66.7 %)
1 (3.7 %)
1 (3.7 %)
0 (0)
3 (11.1 %)
III (n = 3)
1 (33.3 %)
0 (0)
0 (0)
0 (0)
0 (0)
IV (n = 14)
6 (42.9 %)
7 (50 %)
0 (0)
3 (21.4 %)
1 (7.1 %)
V (n = 7)
4 (57.1 %)
1 (14.3 %)
1 (14.3 %)
2 (28.6 %)
1 (14.3 %)
Total (n = 54)
30 (55.6 %)
9 (16.7 %)
2 (3.7 %)
5 (9.3 %)
5 (9.3 %)
P value
NS
0.003
NS
NS
NS
ACL anterior cruciate ligament, PCL posterior cruciate ligament, MCL medial collateral ligament, LCL lateral collateral ligament, NS not significantly
Table 6 shows that a large amount of widening tibial plateau was prone to cause the collateral and cruciate ligament injuries for patients with high-energy type IV and V fractures. For LPWCT, there was significant difference between injured and non-injured collateral and cruciate ligaments in the type IV and V fractures (P \ 0.05). However, the result showed that LPWCT and LPWX-ray were not related to the meniscus injury. LPWCT and LPWX-ray of patients with non-injured meniscus were smaller than those of ones with injured meniscus, but not statistically (P [ 0.05). Furthermore, for LPWX-ray, there was significant difference between injured and non-injured collateral ligament in the type IV and V fractures
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(P \ 0.05), but not significantly for the cruciate ligament injury (P [ 0.05). Thus, when LPWCT and LPWX-ray were, respectively, 10.3 and 8.6 mm, the collateral and cruciate ligaments were susceptible to injury in types IV and V. Further logistic regression was performed to determine whether the amount of LPW and LPD correlates with the incidence and number of soft tissue injuries in tibial plateau fractures. Table 7 shows that, for the tibial plateau fracture caused by low-energy trauma, logistic regression results showed a significant impact of increasing LPWCT/X-ray and LPDCT on the incidence of collateral ligament injury (P \ 0.05). Meanwhile, LPWCT/X-ray and LPDCT/X-ray were associated with the cruciate ligament injury (P \ 0.05).
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Table 8 shows a statistical correlation existed between LPWCT/X-ray and collateral ligament injury (P \ 0.05). LPWCT was significantly related to the cruciate ligament injury. However, LPW and LPD were not related to the meniscus injury in the patients with tibial plateau fracture caused by low- or high-energy trauma (P [ 0.05).
Table 2 Detail of soft tissue injury incidence Associated soft tissue injuries (n = 54)
Number of injuries (%)
Menisci Lateral meniscus peripheral tear
14 (25.9 %)
Lateral meniscus horn tear
12 (22.2 %)
Medial meniscus peripheral tear
6 (11.1 %)
Medial meniscus horn tear
1 (1.9 %)
Discussion
Collateral ligaments LCL tear
5 (9.3 %)
MCL tear
5 (9.3 %)
Tibial plateau fracture is one of the most complex intraarticular injuries in trauma surgery that are associated with a variety of fracture patterns, including lateral and medial plateau split, articular depression, comminution and soft tissue disorders including ligament and meniscus injuries
Cruciate ligaments ACL tear
14 (25.9 %)
PCL tear
2 (3.7 %)
Table 3 Relationship between fracture type and multiple soft tissue injuries
Type
Associated multiple soft tissue injuries 2 Lesions
Frequency of multiple lesions
3 Lesions
I (n = 3)
0
0
0 % (0/2)
II (n = 27)
6
1
25.9 % (7/27)
III (n = 3)
0
0
0 % (0/3)
IV (n = 14)
3
1
28.6 % (4/14)
V (n = 7)
2
0
28.6 % (2/7)
P value
NS
Total (n = 54)
11
2
24.1 % (13/54)
NS not significantly
Table 4 Relationship between low-/high-energy associated fracture type and multiple soft tissue injuries
Type
Associated multiple soft tissue injuries
Frequency of multiple lesions
2 Lesions
3 Lesions
LEF
6
1
21.2 % (7/33)
HEF
5
1
28.6 % (6/21)
P value
NS
LEF low-energy fracture, HEF high-energy fracture, NS not significantly
Table 5 Depression and widening of tibial plateau resulting from low-energy trauma for soft tissue injury
Meniscus No
Yes
Collateral ligament
Cruciate ligament
No
No
Yes
Yes
Associated soft tissue injury 2.2 ± 2 1 3.5 ± 1.7 LPDX-ray
2.6 ± 1.7
5.6 ± 1.5*
2.5 ± 1.8
5.0 ± 1.4*
LPDCT
2.8 ± 2.7
4.2 ± 1.9
3.1 ± 1.8
7.6 ± 2.0*
3.1 ± 2.2
5.9 ± 1.3*
LPWX-ray
2.9 ± 2.6
4.0 ± 1.8
3.1 ± 1.5
7.4 ± 2.7*
3.0 ± 1.8
6.3 ± 1.4*
LPWCT
3.7 ± 3.2
5.1 ± 2.4
3.8 ± 1.6
10.1 ± 3.4*
3.7 ± 2.1
8.2 ± 2.7*
LPWX-ray and LPWCT, the lateral plateau widening by X-ray and MDCT scan; LPDX-ray and LPDCT, the lateral plateau depression by X-ray and MDCT scan * P \ 0.05, compared with non-injured soft tissue
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Eur J Orthop Surg Traumatol Table 6 Widening of tibial plateau resulting from highenergy trauma for soft tissue injury
Meniscus No
Collateral ligament
Cruciate ligament
Yes
No
No
Yes
Yes
Associated soft tissue injury LPWX-ray
7.2 ± 1.8
6.6 ± 3.4
5.1 ± 2.0
8.6 ± 2.6*
5.4 ± 2.4
7.4 ± 2.8
LPWCT
8.4 ± 1.8
8.1 ± 4.7
6.1 ± 2.1
10.3 ± 4.3*
6.2 ± 2.4
9.3 ± 4.2*
LPWX-ray and LPWCT, the lateral plateau widening by X-ray and MDCT scan * P \ 0.05, compared with non-injured soft tissue
Table 7 Logistic regression analysis for the correlation between LPWCT/X-ray/LPDCT/X-ray and soft tissue injuries associated with tibial plateau fracture caused by low-energy trauma
Associated soft tissue injuries
Parameters
OR
95 % CI
P value
Meniscus
LPDCT
1.37
0.79–2.40
0.27
LPDX-ray
1.45
0.78–2.69
0.24
LPWCT
1.02
0.63–1.65
0.92
LPWX-ray
1.04
0.59–1.84
0.902
LPDCT
1.13
0.44–2.92
0.015
LPDX-ray
1.13
0.42–3.03
0.063
LPWCT
1.51
0.78–2.94
0.002
LPWX-ray
1.49
0.69–3.23
0.019
LPDCT LPDX-ray
1.14 1.50
0.68–3.25 0.78–3.94
0.002 0.001
LPWCT
1.27
0.58–2.94
0.003
LPWX-ray
1.27
0.48–2.74
0.003
Collateral ligament
Cruciate ligament
Table 8 Logistic regression analysis for the correlation between LPWCT/X-ray and soft tissue injuries associated with tibial plateau fracture caused by high-energy trauma
Associated soft tissue injuries Meniscus Collateral ligament Cruciate ligament
[2, 3, 9, 10]. The adequate treatment is challenging and has a significant impact on functional outcome. Non-anatomic reduction in the joint surface, malalignment and associated soft tissue lesions may promote the post-traumatic arthritis in these patients [6, 11, 12]. The use of magnetic resonance imaging in diagnosing soft tissue pathology in the knee disorder has been well described [7, 9, 13]. MRI provides sufficient information with regard to specific ligamentous and meniscal injuries. Gardner et al. [9] evaluated 103 operative tibial plateau fractures by the magnetic resonance imaging analysis and reported that 99 % of cases showed evidence of derangement of soft tissue structure around the knee, 77 % complete cruciate or collateral rupture, 74 % lateral meniscus tears, 83 % lateral capsular separations and 44 % medial meniscal tears. Bennett et al. [14] assessed 30 tibial plateau fractures by the pre- and postfixation stress testing and
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Parameters
Odds ratio
95 % CI
P value
LPWCT
1.41
0.47–4.27
0.428
LPWX-ray
0.74
0.2–2.78
0.514
LPWCT
1.48
0.08–2.83
0.01
LPWX-ray
5.76
0.47–4.9
0.004
LPWCT
1.18
0.98–1.83
0.044
LPWX-ray
1.28
0.78–1.83
0.086
diagnostic arthroscopy and illustrated that there was a 56 % frequency of associated soft tissue injuries, including 20 % medial collateral ligament injury, 3 % lateral collateral ligament injury and 20 % meniscus tears. By the arthroscopic testing, Abdel-Hamid et al. [10] reported that the frequency of soft tissue injury in their study was 71 %, 57 % meniscus injury, 25 and 5 %, respectively, for the anterior and posterior cruciate ligament and 3 and 3 %, respectively, for the medial and lateral collateral ligament. In our study, the results showed 55.6 % meniscus injury, 16.7 % ACL injury, 3.7 % PCL injury, 9.3 % MCL injury and 9.3 % LCL injury. The incidence of meniscus injury (55.6 %, 30/54) was higher than that of other soft tissue injury form. Furthermore, most of ACL injury occurred in the type IV and there was significant difference between the five types. These results were similar to the previous studies [8, 9, 14].
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In our trauma center, patients with type VI tibial plateau fracture are operated with stainless steel external fixator in the emergency, and MRI evaluation is not used for them. Thus, only patients with Schatzker I–V tibial plateau fracture were included in our study. It has been reported that articular depression was a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture. They demonstrated a significant impact of increasing tibial plateau fracture depression on the incidence of meniscus lateralis tears. However, our results showed that the meniscal injury was not significantly associated with articular depression and widening. Due to the axial load and varus/valgus force, less plateau depression or widening probably results in the meniscus peripheral tear, accounting for 37 % (20/54) in our study [1, 2, 6, 12]. Thus, the correlation between the articular depression/ widening and meniscal injury was not significant in this study. Furthermore, the present study revealed that meniscus injury was the main type of soft tissue injury in the patients with acute tibial plateau fracture. It has been reported that the anterior cruciate ligament injury is common in the acute type IV tibial plateau, and the results of our study also support this phenomenon [6, 8, 9, 14]. A debilitating outcome of ACL injury is severe knee instability, which can lead to osteoarthritis [15–20]. The ACL is usually surgically reconstructed to restore knee stability [21–23]. The ACL is known to be a restraint against anterior tibial loads by limiting anterior tibial translations [21, 24, 25]. The Schatzker type IV fracture also results from the complex varus/valgus violence and axial load. The previous study illustrated that excessive axial compression load would cause relative displacement and rotation of the tibial with respect to the femur and result in isolated injury to the ACL when the knee was fixed to 60, 90 and 120 [26]. This could explain the phenomenon that type IV fracture is accompanied by the ACL injury. The percentage of soft tissue injuries in type IV is the highest among the all types in our study. This type is common in the high-energy tibial plateau fractures. Meanwhile, in this type, the medial plateau is either split off as a wedge fragment or depressed and comminuted [2]. Some authors proposed that type IV could also be called fracture-dislocation type, which is characterized of lateral column dislocation, and also associated with soft tissue injuries [27]. Schatzker et al. [2] reported that cruciate ligament disruption frequently occurs in association with medial condylar fracture. In the literature, it has been reported that types II and V were also related to the incidence of soft tissue injuries due to the articular depression and dislocation [6–9, 27]. Our result was similar to the studies in the literature. Based on the trauma violence, the Schatzker classification of tibial plateau fracture could be divided into two categories, including types I, II and III for
low-energy trauma and types IV, V and VI for high-energy trauma [28]. Fractures caused by the high-energy trauma are theoretically coupled with multiple soft tissue injuries, and some reports support this idea. Abdel-Hamid et al. [10] reported that the rates of multiple soft tissue injuries in the Schatzker types IV, V and VI were, respectively, 32, 25 and 25 % by the arthroscopic evaluation. In our study, the rates of multiple soft tissue injuries in the low- and highenergy fracture were, respectively, 21.2 and 28.6 %. Furthermore, the multiple soft tissue injuries were common in the type II. This may be related to the case of type VI missing and a small number of cases. The parameters tested by different radiological methods differed greater in our study. It has been reported that a plain anteroposterior radiograph depicting a lateral plateau depression ]14 mm and/or a lateral plateau widening ]10 mm was associated with a significantly increased risk of meniscal injury in Schatzker type II tibial plateau fractures [6]. Many investigators have found that surgical plans based on plain radiographic findings were modified after preoperative computed tomography or magnetic resonance imaging [13, 29]. Schatzker II fractures with depression or widening approaching 5 mm deserve heightened vigilance in diagnosing the soft tissue injuries [7]. In our study, we found that for low-energy trauma, when LPDX-ray ] 5 mm, LPWX-ray ] 6 mm, LPDCT ] 6 mm and/or LPWCT ] 8 mm, we should be aware of the associated soft tissue injuries. Meanwhile, for high-energy trauma, when LPWX-ray ] 7 mm and/or LPWCT ] 9 mm, more attention should be paid on the accompanied soft tissue injuries. The fracture of Schatzker type IV is mainly characterized by the fact that the medial plateau either is split off as a wedge fragment or depressed and comminuted. The Schatzker V fracture line often has the appearance of an inverted Y, not mainly articular depression. Thus, the articular depression was not assessed for patients with type IV and V fractures in our study, based on the characteristics of the two types. There are some limitations for our study. Firstly, the cases were not included the Schatzker VI, and this may exert greater influence on the results. Secondly, although all measurements were made by three authors and the mean values were used for the final analysis, subjective deviation still existed in our study. Furthermore, meniscus injury could be easily observed during the operation, but the cruciate and collateral ligament could not visualized in the operation, influencing by the surgical approach, extent of damage and treatment plan. Thus, we could not make a verification for MRI results. From this perspective, arthroscopic evaluation is better than MRI assessment, but the former one is invasive. In addition, there is a large disadvantage of our study. Namely, due to the less cases, we did not distinguish different injury forms of meniscus
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and ligament, such as tear injury and partial/complete ruptures in our study. Our further study is processing. More cases will be included, and more exact details will be emerged in the future. In conclusion, acute tibial plateau fracture is often associated with the soft tissue injuries, and different radiological methods, such as plain and CT scan, have distinct prediction standards for ligament injuries accompanied with tibial plateau fracture. For low-energy trauma, when LPDX-ray ] 5 mm, LPWX-ray ] 6 mm, LPDCT ] 6 mm and/or LPWCT ] 8 mm, we should be aware of the associated soft tissue injuries. Meanwhile, for high-energy trauma, when LPWX-ray ] 7 mm and/or LPWCT ] 9 mm, more attention should be paid on the accompanied soft tissue injuries. Thus, a plain anteroposterior radiograph and MDCT scan could predict the occurence of soft tissue disorders with tibial plateau fracture.
Conflict of interest of interest.
The authors declare that there are no conflicts
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