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Comparison of three fixations for tibial plateau fractures by biomechanical study and radiographic observation
International Journal of Surgery 13 (2015) 292e296
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Comparison of three fixations for tibial plateau fractures by biomechanical study and radiographic observation Hong-wei Chen a, Guo-dong Liu b, *, Shan Ou c, *, Xie-yuan Jiang d, Jun Fei e, Li-jun Wu f a
Department of Orthopedics, Central Hospital of Yiwu City, Yiwu, Zhejiang Province 322000, China Department 8, Institute of Research Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China c Department of Anesthesiology, General Hospital of Chengdu Military Command, Chengdu, Sichuan 610083, China d Department of Orthopedics, Jishuitan Hospital of Beijing, Beijing 100000, China e Traumatic Center, Institute of Research Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China f Institute of Digitized Medicine, Wenzhou Medical College, Wenzhou 325035, China b
h i g h l i g h t s Effects of three fixation devices for tibial plateau fracture were compared. Axial controlled intramedullary nail had better biomechanical properties. Intramedullary nail resulted in shorter healing time than plate and external fixator.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 6 January 2014 Received in revised form 11 November 2014 Accepted 12 November 2014 Available online 18 November 2014
Aim: The aim of this study was to compare the fixation effects of three fixation devices for tibial plateau fracture (AO/OTA classification 41 A1). Methods: Sixteen human cadaver tibial specimens were randomly divided into four groups. An A1 fracture model was established. The fractures were subsequently fixed by axial controlled intramedullary nail, external fixation and steel plate fixation. Each specimen was subjected to axial compression, torsion test and three-point bending test. Then a rat model was used to evaluate the therapeutic effect of these three fixations by evaluation of callus formation time and healing time. Results: It was found that the axial controlled intramedullary nail group obtained superior biomechanical properties of resistance ability of bending, torsional and axial compressive, compared with external fixation and steel plate group. In animal experiments, the axial controlled intramedullary nail group had a significant shorter callus occurrence and healing time than steel plate and external fixator group. Conclusion: The axial controlled intramedullary nail fixation has a superior biomechanical characteristic and fixation effect for tibial plateau fractures than steel plate and external fixator. © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Keywords: Axial controlled intramedullary nail External fixation Steel plate fixation
1. Introduction A tibial plateau fracture (TPF) involves the articular surface of the proximal tibia that supports the opposing femoral condyle [1]. TPF is often occurred in an elderly population for osteoporosis, and also in a young population increasingly for practicing high-risk sports and using two-wheeled vehicles [2]. TPF can lead to knee instability and knee degeneration in advanced stage if not managed
* Corresponding authors. E-mail address: [email protected] (G.-d. Liu). http://dx.doi.org/10.1016/j.ijsu.2014.11.013 1743-9191/© 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
properly [3]. Proper reduction and mechanical properties of fixation techniques are essential for the tibia functional rehabilitation. The objective of TPF treatment is precise reconstruction of the articular surfaces, stable fragment fixation for early motion, and repair of all concomitant lesions [4,5]. Treatment of TPF includes nonsurgical treatment, and surgical approaches, open reduction and internal fixation, arthroscopy and percutaneous fixation, external fixation, bone grafting [1]. Among which, axial controlled intramedullary nail, external fixator and steel plate fixation are popular recently. Steel plate has attracted sufficient attention due to its fewer trauma and fewer complications [6]. Internal and external fixation devices fixed tibial fractures
H.-w. Chen et al. / International Journal of Surgery 13 (2015) 292e296
have achieved a clinically proven good therapeutic effect. However, in clinical practice, phenomenons of plate broken, intramedullary nail breakage and nails drop happen occasionally which result in inadequate fixation and produces complications such as malunion or nonunion [7], wound infection, skin incision, flap necrosis, and bone compartment syndrome [8,9]. In recent years, aplenty of biomechanical comparative analysis of various fixation methods have been reported for TPF treatment [9e18]. However, controversial opinions still exist concerning the ideal method for TPF and the comparison of healing effect among these fixation devices is lack. The process of fracture healing is a complex sequence of inflammatory reaction, callus formation, tissue differentiation within the callus, and callus resorption and finally bone modeling [19]. Callus formation occurred in the secondary phase (reparative phase) of fracture healing within one or two weeks after injury [20], and it is sensitive to mechanical conditions and influences the course of healing [21]. Therefore, in our experiment we compared the biomechanical behaviors of three different techniques of axial controlled intramedullary nail, external fixator and steel plate fixation on an adult cadavers simulated A1 tibial plateau fracture pattern according to AO/OAT classification [1,22]. Additionally, we evaluated the fixation effects of these methods in a rat tibial fractures model by X-ray radiography to compare the bone callus formation and fracture healing time. 2. Materials and methods All protocols have been approved by Central Hospital of Yiwu City Ethics Committee and performed in accordance with the ethical standards. 2.1. Materials Axial controlled intramedullary nailing of tibia (GK nail, 8 mm/ 240 mm, Shanghai Puwei Medical Instrument Co., Ltd., China); steel tibial fracture plates (YJBL03,length: 123 mm/155 mm/187 mm, Changzhou Huasen medical appliance Co., Ltd., China); tibia external fixator (Ø11 mm, Shimadzu, Japan); electronic universal testing machine (AG-10TA, Shimadzu, Japan); polymethylmethacrylate (denture powder, Shanghai dental materials Factory, China); fixture (Shanghai mechanical experiment Center, China). 2.2. Biomechanical experiments 2.2.1. Specimens preparation A total of 16 pairs of fresh frozen human cadaveric tibias (Department of Anatomy, Shanghai Medical University, China) were randomly divided into four groups, intramedullary nail group, steel plate group, external fixator group, and control group. Excepting control group, the tibia specimens of the rest three groups were sawed off by a wire saw to make a tibial plateau fracture model (AO/OTA classification 41 A1). The fractures were fixed by axial controlled intramedullary nail, steel plate and external fixator, respectively. Then the two ends of specimen were embedded with dentures powder for biomechanical test. The remaining four complete tibias were performed as control group. 2.2.2. Measurement of the bone mineral density A Dual-energy X-ray absorptiometry (DXA, Hologic Inc., Bedford, MA, USA) was used to determine the bone mineral density of the cadaveric specimens in each group. The values of bone mineral density is represented by T-score which is the most significant
293
index reflecting the severity of osteoporosis. The T-score is the SD of which comparing the measured bone mineral density value with that of healthy people aged 30e35 years old. T > 1.0 means normal bone; 2.5 T 1.0 indicates osteopenia; T < 2.5 suggests osteoporosis. 2.2.3. Biomechanical testing StresseStrain indicators of the tibias in control group were tested to determine the instrument parameters. The parameters were set as: the vertical compressive stress 0e1000 N, torsion angle 0e3 , three-point bending stress 0e400 N. The day before biomechanical testing, the specimens were rewarmed in saline at 37 C, and square fixing pads were made by denture powder in both ends of the specimens. An electronic universal testing machine (HegewaldePeschke, Nossen, Germany) was used to perform the biomechanical testing. Axial compression, torsion and three-point bending tests were conducted on each specimen. 2.2.3.1. Axial compression test. Tibia fracture model was embedded on the biomechanical testing machine. The probe (transferring the strain value to a computer) was installed in the both ends of fracture line. The applied vertical load was gradually increased from 0 N to a maximum load of 1000 N with a loading rate of 1 mm/s. The vertical strain and lateral strain values were outputted automatically by a computer data acquisition system. A set of data was recorded in each 100 N (totally 10 sets) for statistical analysis. 2.2.3.2. Torsion test. The specimens of the model groups were clamped on both ends at the middle of biomechanical testing machine axle. A left and right direction torsional stiffness test was conducted with a torsion rate of 2 /s, and the torsion angle was 3 . The torsion value was recorded with a computer data acquisition system. The data at intervals of 0.3 (totally 10 sets) was collected for statistical analysis. 2.2.3.3. Three-point bending test. The three-point bending test was conducted with a similar procedure as the axial compression. A continuous tibial front loading stress of 0e400 N was applied with a loading rate of 1 mm/s. A vertical direction stress value of every 50 N (totally 8 sets) was selected for statistical analysis. 2.3. Animal experiments 2.3.1. Animal and modeling A total of 30 Wistar rats (body weight 280 ± 30 g, 15 males and 15 females) were used for modeling of tibia plateau fractures in this study. The protocol was in accordance with the principles of the Guide for the Care and Use of Laboratory Animals [23]. Sodium pentobarbital (1%) were administrated to rats by intraperitoneal injection at the dose of 3 mg/100 g for anesthesia. The rat limbs were fixed on the operating table. After preoperative hair removal with barium sulfide, a 1 cm straight incision was made on the skin of front side of hind limb into deep fascia. The tibia was exposed after separating the abductor hallucis longus and the musculus extensor carpi radialis longus. A hand surgery saw was used to make a tibial plateau fracture model by sawing in the bilateral tibia, resulting in a 1-mm wide single fracture. Postoperative wound suture was performed without dressing or fixation. The rats were marked with picric acid in back. After waking up, the rates were fed ad libitum in the cage. In the first 3 days after modeling, each rat received an intramuscular injection of penicillin 40,000 U/d to prevent infection. During the process of modeling, 3 rats died because of inflammation. The fixation was performed after the soft tissue swelling subsided, if any (about 3e5 days).
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2.3.2. Grouping and fixation The remaining 27 rats were divided into four groups (9 rats in each group), steel plate fixation group, external fixation group, intramedullary nail group. Rats in intramedullary nailing group received traction and reduction under photoscope. Two intramedullary nailing were inserted into the in guidance of sighting device proximal tibia and distal tibia, respectively. After callus formation (about two months), the two distal nails were replaced by dynamic fixation. Steel plate fixation was performed by fixing the fracture with internal fixation plate under direct vision in a tibialis anterior lateral arc-shaped incision. External fixation, closed pin reduction and fixation under photoscope, for some severe comminuted fracture displacement, a limited open pin reduction and fixation was conducted. Seven weeks later, all rats were sacrificed by decapitation and the tibias were taken out for observation of the fracture healing. The clinical criteria of facture healing were (1) no local tenderness, nor longitudinal percussion pain; (2) no local abnormal activity; (3) X-ray showed blurry fracture lines and continuous bone callus through the fracture line; (4) the fracture is not deformed within two weeks, then the first days of observation is the clinical healing date. 2.3.3. Radiographic observation X-ray film of bilateral tibia was taken the day and every 2days after modeling for observation of the healing process. 2.4. Statistical analysis Data was expressed as mean ± standard deviation. Statistics were performed by SPSS 12.0 software (SPSS Inc, Chicago, IL). P < 0.05 was considered to be statistically significant. 3. Results 3.1. Biomechanical experiments The biomechanical results of the individual groups are displayed in Table 1. The results showed that there was no significant difference among the four groups in bone mineral density. The T-scores in all groups were more than 1.0, indicating that all the bones were normal. 3.1.1. Axial compression test The vertical strain values in steel plate, intramedullary nail, external fixator group were 0.449 ± 0.241, 0.093 ± 0.003, 0.139 ± 0.005, respectively. The vertical compression strain in intramedullary nail group was statistically lower than the steel plat group and external fixation group (P < 0.01). The lateral strain values of steel plate, intramedullary nail, external fixator group were respectively 0.1200 ± 0.0004,0.1275 ± 0.0100, 0.2370 ± 0.0006, with a significant difference among steel plate group, external fixator group and intramedullary nail group (P < 0.01), but no difference between steel plates group and intramedullary nail group (P > 0.05).
Fig. 1. The tibia X-Ray film before and after fixation of internal steel plate (A), external fixator (B) and intramedullary nail (C).
3.1.2. Torsion test The torsion values of steel plate, intramedullary nail, external fixator group were (5.066 ± 2.715) 103, (4.171 ± 2.527) 103,
Table 1 The results of biomechanical testing of the human cadaveric tibias in different groups. Group
Vertical compression
Steel plate (n ¼ 4) External fixator (n ¼ 4) Intramedullary nail (n ¼ 4) Control (n ¼ 4)
0.449 0.139 0.093 0.0569
± ± ± ±
**P < 0.01 vs. intramedullary nail group;
0.241** 0.005## 0.003 0.005 ##
Lateral compression 0.1200 0.2370 0.1275 0.1055
± ± ± ±
0.0004 0.0006## 0.0100xx 0.0004
Torsion 103 Nm 5.066 4.570 4.171 4.066
± ± ± ±
2.715** 2.228## 2.527xx 2.215
Three-point bending 0.049 0.062 0.039 0.024
± ± ± ±
0.009** 0.009## 0.017xx 0.007
P < 0.01 vs. steel plate group; xxP < 0.01 vs. external fixation group.
T-score of bone mineral density measurement 0.052 0.067 0.072 0.052
± ± ± ±
0.012 0.015 0.0008 0.012
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(4.570 ± 2.228) 103 Nm, and differences between any two groups were statistically significant (P < 0.01). 3.1.3. Three-point bending test The strain of three-point bending test were different significantly among the test groups (P < 0.01), external fixator group > steel plate group > intramedullary nail group. 3.2. Healing effect in animal model Among the 27 model rats, 3 died during the process of healing: one rat died in intramedullary nail group; one died due to inflammation in steel plate internal fixation group; and one died due to inflammation in external fixation group. Thus, there were 8 cases in each group. The tibia X-Ray films before and after reduction of three fixation devices were displayed in Fig. 1. The results showed that all the three kinds of devices achieved a required three-dimensional fixation effects. In addition, the strength and stability of the tibia have reached normal level. After destruction of the specimen, no morphological changes or screws bent, and the tibia in region of internal fixation device placed was not damaged. Callus occurrence time and fracture healing time are shown in Table 2. It can be seen that within seven weeks after surgery, fractures in the three groups were all healed. The callus occurrence time and fracture healing time of intramedullary nail group are shorter than internal fixation and external fixation (P < 0.05). This indicated that intramedullary nail have a superior ability for tibial plateau fractures rehabilitation. 4. Discussion In this study, the biomechanical characteristics of three fixation devices (plate, external fixator, and intramedullary nail) in human cadaver simulated TPF model were tested. Moreover, the callus formation and the fracture healing time in rat model fixed by three devices were compared. The results showed that intramedullary nail group had a superior biomechanical properties and shorter callus occurrence time and fracture healing time than steel plate and external fixator group. The most frequent reasons for TPF injuries are falls, traffic accidents and sports trauma [1,24]. TPF is associated to the meniscus and ligaments injuries. Approximately half of plateau fractures were found to have meniscal injuries that were amenable to surgical treatment [25]. One third of fractures were accompanied by ligament injuries [26]. Therefore, maximal preservation of the meniscus and surface congruity are crucial to a lasting satisfactory outcome after a fracture of the tibial plateau [1]. The aggressiveness of treatment should be matched by the reduction and stabilization needs of the fracture pattern using the least invasive ways to achieve a congruent and level articular surface with stability sufficient to allow early motion [1]. Plate stabilization had been widely employed for TPF treatment and achieved a high-success rate [5,17,27]. However, the disadvantages of plate of stress shielding, great damage to the blood
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supply of fracture, fracture healing delays have increasingly attracted widespread attention [28e30]. In this study, we found that fracture healing time is longer compared with external fixation and intramedullary nail group. External fixation plays an important role in some simple fixation or in patients with severe soft tissue injury, but the fixing strength is insufficient [7,31,32]. External fixators must be maintained until healing has occurred, which can be problematic due to pin or wire site complications [33]. Additionally, other disadvantages, such as fixed needle loosening, pin tract infection, needle around oppressive skin necrosis also limited its widespread use [34]. Our study indicated that the biomechanical characteristics of external fixation are weaker and healing time is longer significantly than intramedullary nailing. The benefits of intramedullary nailing include load sharing, sparing of the extraosseous blood supply, and avoidance of additional soft-tissue dissection, thereby minimizing the risk of postoperative complications [35]. Recently, increasing researchers have begun to focus on intramedullary nailing for TPF. Morandi et al. [36] reported that the lateral percutaneous suprapatellar intramedullary nailing approach in a semi-extended position is an excellent approach for tibial fractures. Feng et al. [10] indicated that intramedullary nailing has good mechanical properties compared with dynamic compression plate, locking compress ion plate and external fixation. Hogel et al. [14] found that locked intramedullary nailing of proximal tibia fractures leads to a stiffer implant-bone construct than plating and no adverse effects were found after nailing. Therefore, they proposed nailing to be a good alternative to plating for tibial plateau fractures, especially in patients with soft tissue problems. In our study, it was confirmed that intramedullary nail had superior biomechanical characteristics of resistance ability of bending, torsional and axial compressive. Moreover, in the present study, callus occurrence and healing time for TPF treatment were shorter than steel plate and external fixator. This is because intramedullary nail is an elastic fixation without compression around the fracture, and slight passive or active physical activity was existed in fracture site, which is conducive to callus formation [37,38]. However, intramedullary nail technique has negative effects of causing infection. In the present study, one case died due to inflammation, which was equal to the other two groups. In conclusion, intramedullary nail has superior biomechanical characteristics in human adults cadaver tibia model of A1 tibial plateau fracture, additionally, better clinical effects in animal experiment than steel plate and external fixator. However, tibial plateau fractures often have a spiral or comminuted component and findings from the A1 model may not address these. Thus, additional plate buttressing may be recommended for stability. More clinical trials are necessary for widespread use of intramedullary nail fixation for tibial plateau fractures treatment. Ethical approval All animal studies have been approved by Central Hospital of Yiwu City Ethics Committee and performed in accordance with the ethical standards. Author contribution
Table 2 Callus appeared time and fracture healing time of rats tibia fixed by three fixation methods (n ¼ 8). Group
Callus appeared time (d)
Healing time (d)
Steel plate External fixator Intramedullary nail
14 ± 1.92** 18 ± 2.47## 12 ± 1.1xx
39 ± 4.73** 48 ± 4.46## 32 ± 3.73xx
**P < 0.01 vs. intramedullary nail group; ## P < 0.01 vs. steel plate group.
xx
P < 0.01 vs. external fixator group;
Hong-wei Chen: study design, data analysis, writing. Guo-dong Liu: study design, data analysis, writing and final approval of the manuscript. Xie-yuan Jiang: data collection, statistical process and photo precess. Jun Fei: data collections, writing statistical process. Li-jun Wu: data collections, writing. All authors have read and approved the manuscript.
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Conflicts of interest None. Acknowledgment This study was supported by the grants from Project of Zhejiang Science and Technology Department (2013C33216), and Zhejiang Wenzhou Medical College Scientific Development Foundation of China (QTJ06012). References [1] J.S. Reid, Fractures of the Tibial Plateau, in: Orthopaedic Knowledge Update Trauma Rosemont, American Academy of Orthopaedic Surgeons, 1996, pp. 159e169. [2] T. Vendeuvre, D. Babusiaux, C. Breque, et al., Tuberoplasty: minimally invasive osteosynthesis technique for tibial plateau fractures, Orthop. Traumatol. Surg. Res. e OTSR 99 (2013) S267eS272. [3] D.P. Weigel, J.L. Marsh, High-energy fractures of the tibial plateau knee function after longer follow-up, J. Bone Jt. Surg. 84 (2002) 1541e1551. [4] B.K. Markhardt, J.M. Gross, J. Monu, Schatzker classification of tibial plateau fractures: use of CT and MR imaging improves assessment, Radiographics 29 (2009) 585e597. [5] H. Tscherne, P. Lobenhoffer, Tibial plateau fractures: management and expected results, Clin. Orthop. Relat. Res. 292 (1993) 87e100. [6] A. Foux, A.J. Yeadon, H.K. Uhthoff, Improved fracture healing with less rigid plates: a biomechanical study in dogs, Clin. Orthop. Relat. Res. 339 (1997) 232e245. [7] U. Alfahd, S.E. Roth, D. Stephen, C.M. Whyne, Biomechanical comparison of intramedullary nail and blade plate fixation for tibiotalocalcaneal arthrodesis, J. Orthop. Trauma 19 (2005) 703e708. [8] J. Verbruggen, J. Stapert, Failure of reamed nailing in humeral non-union: an analysis of 26 patients, Injury 36 (2005) 430e438. [9] C. Wu, C. Tai, A biomechanical comparison of unlocked or locked reamed intramedullary nails in the treatment of mid-third simple transverse femoral shaft fractures, Chang Gung Med. J. 29 (2006) 275. [10] W. Feng, L. Fu, J. Liu, X. Qi, D. Li, C. Yang, Biomechanical evaluation of various fixation methods for proximal extra-articular tibial fractures, J. Surg. Res. 178 (2012) 722e727. [11] F. Zhim, G.Y. Laflamme, H. Viens, K. Saidane, L.H. Yahia, Biomechanical stability of high tibial opening wedge osteotomy: internal fixation versus external fixation, Clin. Biomech. 20 (2005) 871e876. [12] A.M. Ali, M. Saleh, S. Bolongaro, L. Yang, Experimental model of tibial plateau fracture for biomechanical testing, J. Biomech. 39 (2006) 1355e1360. [13] H. Cift, O. Cetik, B. Kalaycioglu, M.H. Dirikoglu, K. Ozkan, F. Eksioglu, Biomechanical comparison of plate-screw and screw fixation in medial tibial plateau fractures (Schatzker 4). A model study, Orthop. Traumatol. Surg. Res. : OTSR 96 (2010) 263e267. [14] F. Hogel, S. Hoffmann, S. Panzer, J. Wimber, V. Buhren, P. Augat, Biomechanical comparison of intramedullar versus extramedullar stabilization of intraarticular tibial plateau fractures, Arch. Orthop. Trauma Surg. 133 (2013) 59e64. [15] M.A. Karunakar, K.A. Egol, R. Peindl, M.E. Harrow, M.J. Bosse, J.F. Kellam, Split depression tibial plateau fractures: a biomechanical study, J. Orthop. Trauma 16 (2002) 172e177.
[16] N.G. Lasanianos, C. Garnavos, E. Magnisalis, S. Kourkoulis, G.C. Babis, A comparative biomechanical study for complex tibial plateau fractures: nailing and compression bolts versus modern and traditional plating, Injury 44 (10) (2013) 1333e1339. [17] C.C. Wu, C.L. Tai, Plating treatment for tibial plateau fractures: a biomechanical comparison of buttress and tension band positions, Arch. Orthop. Trauma Surg. 127 (2007) 19e24. [18] W. Zhang, C.F. Luo, S. Putnis, H. Sun, Z.M. Zeng, B.F. Zeng, Biomechanical analysis of four different fixations for the posterolateral shearing tibial plateau fracture, Knee 19 (2012) 94e98. [19] D. Lacroix, P. Prendergast, A mechano-regulation model for tissue differentiation during fracture healing: analysis of gap size and loading, J. Biomech. 35 (2002) 1163e1171. [20] A. Phillips, Overview of the fracture healing cascade, Injury 36 (2005) S5eS7. [21] P. Klein, H. Schell, F. Streitparth, et al., The initial phase of fracture healing is specifically sensitive to mechanical conditions, J. Orthop. Res. 21 (2003) 662e669. [22] M. Muller, S. Nazarian, P. Koch, Classification AO des fractures, Springer, 1987. [23] Resources IoLA, Guide for the Care and Use of Laboratory Animals, National Academies Press, 1996. [24] A. Weimann, T. Heinkele, M. Herbort, B. Schliemann, W. Petersen, M.J. Raschke, Minimally invasive reconstruction of lateral tibial plateau fractures using the jail technique: a biomechanical study, BMC Musculoskelet. Disord. 14 (2013) 120. [25] C. Vangsness, B. Ghaderi, M. Hohl, T.M. Moore, Arthroscopy of meniscal injuries with tibial plateau fractures, J. Bone Jt. Surg. Br. Vol. 76 (1994) 488e490. [26] W.F. Bennett, B. Browner, Tibial plateau fractures: a study of associated soft tissue injuries, J. Orthop. Trauma 8 (1994) 183e188. €tzli, Treatment of tibial plateau fractures with [27] F.T. Ballmer, R. Hertel, H.P. No small fragment internal fixation: a preliminary report, J. Orthop. Trauma 14 (2000) 467. [28] U. Heim, K.M. Pfeiffer, J. Brennwald, A. für Osteosynthesefragen, Internal Fixation of Small Fractures: Technique Recommended by the AO-ASIF Group, Springer-Verlag, 1988. [29] H. Willenegger, 104. 20 Jahre Arbeitsgemeinschaft für Osteosynthesefragen (AO), Langenbecks Arch. Chir. 352 (1980) 357e364. [30] P. Reber, H. Ris, R. Inderbitzi, B. Stark, B. Nachbur, Osteosynthesis of the injured chest wall; use of the AO (Arbeitsgemeinschaft für Osteosynthese) technique, Scand. Cardiovasc. J. 27 (1993) 137e142. [31] A.M. Ali, M. Burton, M. Hashmi, M. Saleh, Treatment of displaced bicondylar tibial plateau fractures (OTA-41C2&3) in patients older than 60 years of age, J. Orthop. Trauma 17 (2003) 346e352. [32] E. Hasenboehler, W.R. Smith, L. Laudicina, G.C. Philips, P.F. Stahel, S.J. Morgan, J. Orthop. Surg. Res. 1 (2006) 16. [33] R.D. Zura, J.A. Browne, M.D. Black, S.A. Olson, Current management of highenergy tibial plateau fractures, Curr. Orthop. 21 (2007) 229e235. [34] C.C. Edwards, S.C. Simmons, B.D. Browner, M.C. Weigel, Results treating 202 injuries with external fixation, Clin. Orthop. Relat. Res. 230 (1988) 98e115. [35] T.G. Hiesterman, B.X. Shafiq, P.A. Cole, Intramedullary nailing of extraarticular proximal tibia fractures, J. Am. Acad. Orthop. Surg. 19 (2011) 690e700. [36] M. Morandi, T. Banka, G.P. Gaiarsa, et al., Intramedullary nailing of tibial fractures: review of surgical techniques and description of a percutaneous lateral suprapatellar approach, Orthopedics 33 (2010) 172e179. [37] T. Yamaji, K. Ando, O. Washimi, N. Terada, H. Yamada, T. Seki, Callus formation after intramedullary nailing for femoral fracture e a comparison study between interlocked and ender nailing, J. Bone Jt. Surg. Br. Vol. 85-B (28) (2003). [38] V. Smrkolj, Physiological Principles of Intramedullary Nailing, 2007.
Contents lists available at ScienceDirect
International Journal of Surgery journal homepage: www.journal-surgery.net
Original research
Comparison of three fixations for tibial plateau fractures by biomechanical study and radiographic observation Hong-wei Chen a, Guo-dong Liu b, *, Shan Ou c, *, Xie-yuan Jiang d, Jun Fei e, Li-jun Wu f a
Department of Orthopedics, Central Hospital of Yiwu City, Yiwu, Zhejiang Province 322000, China Department 8, Institute of Research Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China c Department of Anesthesiology, General Hospital of Chengdu Military Command, Chengdu, Sichuan 610083, China d Department of Orthopedics, Jishuitan Hospital of Beijing, Beijing 100000, China e Traumatic Center, Institute of Research Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China f Institute of Digitized Medicine, Wenzhou Medical College, Wenzhou 325035, China b
h i g h l i g h t s Effects of three fixation devices for tibial plateau fracture were compared. Axial controlled intramedullary nail had better biomechanical properties. Intramedullary nail resulted in shorter healing time than plate and external fixator.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 6 January 2014 Received in revised form 11 November 2014 Accepted 12 November 2014 Available online 18 November 2014
Aim: The aim of this study was to compare the fixation effects of three fixation devices for tibial plateau fracture (AO/OTA classification 41 A1). Methods: Sixteen human cadaver tibial specimens were randomly divided into four groups. An A1 fracture model was established. The fractures were subsequently fixed by axial controlled intramedullary nail, external fixation and steel plate fixation. Each specimen was subjected to axial compression, torsion test and three-point bending test. Then a rat model was used to evaluate the therapeutic effect of these three fixations by evaluation of callus formation time and healing time. Results: It was found that the axial controlled intramedullary nail group obtained superior biomechanical properties of resistance ability of bending, torsional and axial compressive, compared with external fixation and steel plate group. In animal experiments, the axial controlled intramedullary nail group had a significant shorter callus occurrence and healing time than steel plate and external fixator group. Conclusion: The axial controlled intramedullary nail fixation has a superior biomechanical characteristic and fixation effect for tibial plateau fractures than steel plate and external fixator. © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
Keywords: Axial controlled intramedullary nail External fixation Steel plate fixation
1. Introduction A tibial plateau fracture (TPF) involves the articular surface of the proximal tibia that supports the opposing femoral condyle [1]. TPF is often occurred in an elderly population for osteoporosis, and also in a young population increasingly for practicing high-risk sports and using two-wheeled vehicles [2]. TPF can lead to knee instability and knee degeneration in advanced stage if not managed
* Corresponding authors. E-mail address: [email protected] (G.-d. Liu). http://dx.doi.org/10.1016/j.ijsu.2014.11.013 1743-9191/© 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.
properly [3]. Proper reduction and mechanical properties of fixation techniques are essential for the tibia functional rehabilitation. The objective of TPF treatment is precise reconstruction of the articular surfaces, stable fragment fixation for early motion, and repair of all concomitant lesions [4,5]. Treatment of TPF includes nonsurgical treatment, and surgical approaches, open reduction and internal fixation, arthroscopy and percutaneous fixation, external fixation, bone grafting [1]. Among which, axial controlled intramedullary nail, external fixator and steel plate fixation are popular recently. Steel plate has attracted sufficient attention due to its fewer trauma and fewer complications [6]. Internal and external fixation devices fixed tibial fractures
H.-w. Chen et al. / International Journal of Surgery 13 (2015) 292e296
have achieved a clinically proven good therapeutic effect. However, in clinical practice, phenomenons of plate broken, intramedullary nail breakage and nails drop happen occasionally which result in inadequate fixation and produces complications such as malunion or nonunion [7], wound infection, skin incision, flap necrosis, and bone compartment syndrome [8,9]. In recent years, aplenty of biomechanical comparative analysis of various fixation methods have been reported for TPF treatment [9e18]. However, controversial opinions still exist concerning the ideal method for TPF and the comparison of healing effect among these fixation devices is lack. The process of fracture healing is a complex sequence of inflammatory reaction, callus formation, tissue differentiation within the callus, and callus resorption and finally bone modeling [19]. Callus formation occurred in the secondary phase (reparative phase) of fracture healing within one or two weeks after injury [20], and it is sensitive to mechanical conditions and influences the course of healing [21]. Therefore, in our experiment we compared the biomechanical behaviors of three different techniques of axial controlled intramedullary nail, external fixator and steel plate fixation on an adult cadavers simulated A1 tibial plateau fracture pattern according to AO/OAT classification [1,22]. Additionally, we evaluated the fixation effects of these methods in a rat tibial fractures model by X-ray radiography to compare the bone callus formation and fracture healing time. 2. Materials and methods All protocols have been approved by Central Hospital of Yiwu City Ethics Committee and performed in accordance with the ethical standards. 2.1. Materials Axial controlled intramedullary nailing of tibia (GK nail, 8 mm/ 240 mm, Shanghai Puwei Medical Instrument Co., Ltd., China); steel tibial fracture plates (YJBL03,length: 123 mm/155 mm/187 mm, Changzhou Huasen medical appliance Co., Ltd., China); tibia external fixator (Ø11 mm, Shimadzu, Japan); electronic universal testing machine (AG-10TA, Shimadzu, Japan); polymethylmethacrylate (denture powder, Shanghai dental materials Factory, China); fixture (Shanghai mechanical experiment Center, China). 2.2. Biomechanical experiments 2.2.1. Specimens preparation A total of 16 pairs of fresh frozen human cadaveric tibias (Department of Anatomy, Shanghai Medical University, China) were randomly divided into four groups, intramedullary nail group, steel plate group, external fixator group, and control group. Excepting control group, the tibia specimens of the rest three groups were sawed off by a wire saw to make a tibial plateau fracture model (AO/OTA classification 41 A1). The fractures were fixed by axial controlled intramedullary nail, steel plate and external fixator, respectively. Then the two ends of specimen were embedded with dentures powder for biomechanical test. The remaining four complete tibias were performed as control group. 2.2.2. Measurement of the bone mineral density A Dual-energy X-ray absorptiometry (DXA, Hologic Inc., Bedford, MA, USA) was used to determine the bone mineral density of the cadaveric specimens in each group. The values of bone mineral density is represented by T-score which is the most significant
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index reflecting the severity of osteoporosis. The T-score is the SD of which comparing the measured bone mineral density value with that of healthy people aged 30e35 years old. T > 1.0 means normal bone; 2.5 T 1.0 indicates osteopenia; T < 2.5 suggests osteoporosis. 2.2.3. Biomechanical testing StresseStrain indicators of the tibias in control group were tested to determine the instrument parameters. The parameters were set as: the vertical compressive stress 0e1000 N, torsion angle 0e3 , three-point bending stress 0e400 N. The day before biomechanical testing, the specimens were rewarmed in saline at 37 C, and square fixing pads were made by denture powder in both ends of the specimens. An electronic universal testing machine (HegewaldePeschke, Nossen, Germany) was used to perform the biomechanical testing. Axial compression, torsion and three-point bending tests were conducted on each specimen. 2.2.3.1. Axial compression test. Tibia fracture model was embedded on the biomechanical testing machine. The probe (transferring the strain value to a computer) was installed in the both ends of fracture line. The applied vertical load was gradually increased from 0 N to a maximum load of 1000 N with a loading rate of 1 mm/s. The vertical strain and lateral strain values were outputted automatically by a computer data acquisition system. A set of data was recorded in each 100 N (totally 10 sets) for statistical analysis. 2.2.3.2. Torsion test. The specimens of the model groups were clamped on both ends at the middle of biomechanical testing machine axle. A left and right direction torsional stiffness test was conducted with a torsion rate of 2 /s, and the torsion angle was 3 . The torsion value was recorded with a computer data acquisition system. The data at intervals of 0.3 (totally 10 sets) was collected for statistical analysis. 2.2.3.3. Three-point bending test. The three-point bending test was conducted with a similar procedure as the axial compression. A continuous tibial front loading stress of 0e400 N was applied with a loading rate of 1 mm/s. A vertical direction stress value of every 50 N (totally 8 sets) was selected for statistical analysis. 2.3. Animal experiments 2.3.1. Animal and modeling A total of 30 Wistar rats (body weight 280 ± 30 g, 15 males and 15 females) were used for modeling of tibia plateau fractures in this study. The protocol was in accordance with the principles of the Guide for the Care and Use of Laboratory Animals [23]. Sodium pentobarbital (1%) were administrated to rats by intraperitoneal injection at the dose of 3 mg/100 g for anesthesia. The rat limbs were fixed on the operating table. After preoperative hair removal with barium sulfide, a 1 cm straight incision was made on the skin of front side of hind limb into deep fascia. The tibia was exposed after separating the abductor hallucis longus and the musculus extensor carpi radialis longus. A hand surgery saw was used to make a tibial plateau fracture model by sawing in the bilateral tibia, resulting in a 1-mm wide single fracture. Postoperative wound suture was performed without dressing or fixation. The rats were marked with picric acid in back. After waking up, the rates were fed ad libitum in the cage. In the first 3 days after modeling, each rat received an intramuscular injection of penicillin 40,000 U/d to prevent infection. During the process of modeling, 3 rats died because of inflammation. The fixation was performed after the soft tissue swelling subsided, if any (about 3e5 days).
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2.3.2. Grouping and fixation The remaining 27 rats were divided into four groups (9 rats in each group), steel plate fixation group, external fixation group, intramedullary nail group. Rats in intramedullary nailing group received traction and reduction under photoscope. Two intramedullary nailing were inserted into the in guidance of sighting device proximal tibia and distal tibia, respectively. After callus formation (about two months), the two distal nails were replaced by dynamic fixation. Steel plate fixation was performed by fixing the fracture with internal fixation plate under direct vision in a tibialis anterior lateral arc-shaped incision. External fixation, closed pin reduction and fixation under photoscope, for some severe comminuted fracture displacement, a limited open pin reduction and fixation was conducted. Seven weeks later, all rats were sacrificed by decapitation and the tibias were taken out for observation of the fracture healing. The clinical criteria of facture healing were (1) no local tenderness, nor longitudinal percussion pain; (2) no local abnormal activity; (3) X-ray showed blurry fracture lines and continuous bone callus through the fracture line; (4) the fracture is not deformed within two weeks, then the first days of observation is the clinical healing date. 2.3.3. Radiographic observation X-ray film of bilateral tibia was taken the day and every 2days after modeling for observation of the healing process. 2.4. Statistical analysis Data was expressed as mean ± standard deviation. Statistics were performed by SPSS 12.0 software (SPSS Inc, Chicago, IL). P < 0.05 was considered to be statistically significant. 3. Results 3.1. Biomechanical experiments The biomechanical results of the individual groups are displayed in Table 1. The results showed that there was no significant difference among the four groups in bone mineral density. The T-scores in all groups were more than 1.0, indicating that all the bones were normal. 3.1.1. Axial compression test The vertical strain values in steel plate, intramedullary nail, external fixator group were 0.449 ± 0.241, 0.093 ± 0.003, 0.139 ± 0.005, respectively. The vertical compression strain in intramedullary nail group was statistically lower than the steel plat group and external fixation group (P < 0.01). The lateral strain values of steel plate, intramedullary nail, external fixator group were respectively 0.1200 ± 0.0004,0.1275 ± 0.0100, 0.2370 ± 0.0006, with a significant difference among steel plate group, external fixator group and intramedullary nail group (P < 0.01), but no difference between steel plates group and intramedullary nail group (P > 0.05).
Fig. 1. The tibia X-Ray film before and after fixation of internal steel plate (A), external fixator (B) and intramedullary nail (C).
3.1.2. Torsion test The torsion values of steel plate, intramedullary nail, external fixator group were (5.066 ± 2.715) 103, (4.171 ± 2.527) 103,
Table 1 The results of biomechanical testing of the human cadaveric tibias in different groups. Group
Vertical compression
Steel plate (n ¼ 4) External fixator (n ¼ 4) Intramedullary nail (n ¼ 4) Control (n ¼ 4)
0.449 0.139 0.093 0.0569
± ± ± ±
**P < 0.01 vs. intramedullary nail group;
0.241** 0.005## 0.003 0.005 ##
Lateral compression 0.1200 0.2370 0.1275 0.1055
± ± ± ±
0.0004 0.0006## 0.0100xx 0.0004
Torsion 103 Nm 5.066 4.570 4.171 4.066
± ± ± ±
2.715** 2.228## 2.527xx 2.215
Three-point bending 0.049 0.062 0.039 0.024
± ± ± ±
0.009** 0.009## 0.017xx 0.007
P < 0.01 vs. steel plate group; xxP < 0.01 vs. external fixation group.
T-score of bone mineral density measurement 0.052 0.067 0.072 0.052
± ± ± ±
0.012 0.015 0.0008 0.012
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(4.570 ± 2.228) 103 Nm, and differences between any two groups were statistically significant (P < 0.01). 3.1.3. Three-point bending test The strain of three-point bending test were different significantly among the test groups (P < 0.01), external fixator group > steel plate group > intramedullary nail group. 3.2. Healing effect in animal model Among the 27 model rats, 3 died during the process of healing: one rat died in intramedullary nail group; one died due to inflammation in steel plate internal fixation group; and one died due to inflammation in external fixation group. Thus, there were 8 cases in each group. The tibia X-Ray films before and after reduction of three fixation devices were displayed in Fig. 1. The results showed that all the three kinds of devices achieved a required three-dimensional fixation effects. In addition, the strength and stability of the tibia have reached normal level. After destruction of the specimen, no morphological changes or screws bent, and the tibia in region of internal fixation device placed was not damaged. Callus occurrence time and fracture healing time are shown in Table 2. It can be seen that within seven weeks after surgery, fractures in the three groups were all healed. The callus occurrence time and fracture healing time of intramedullary nail group are shorter than internal fixation and external fixation (P < 0.05). This indicated that intramedullary nail have a superior ability for tibial plateau fractures rehabilitation. 4. Discussion In this study, the biomechanical characteristics of three fixation devices (plate, external fixator, and intramedullary nail) in human cadaver simulated TPF model were tested. Moreover, the callus formation and the fracture healing time in rat model fixed by three devices were compared. The results showed that intramedullary nail group had a superior biomechanical properties and shorter callus occurrence time and fracture healing time than steel plate and external fixator group. The most frequent reasons for TPF injuries are falls, traffic accidents and sports trauma [1,24]. TPF is associated to the meniscus and ligaments injuries. Approximately half of plateau fractures were found to have meniscal injuries that were amenable to surgical treatment [25]. One third of fractures were accompanied by ligament injuries [26]. Therefore, maximal preservation of the meniscus and surface congruity are crucial to a lasting satisfactory outcome after a fracture of the tibial plateau [1]. The aggressiveness of treatment should be matched by the reduction and stabilization needs of the fracture pattern using the least invasive ways to achieve a congruent and level articular surface with stability sufficient to allow early motion [1]. Plate stabilization had been widely employed for TPF treatment and achieved a high-success rate [5,17,27]. However, the disadvantages of plate of stress shielding, great damage to the blood
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supply of fracture, fracture healing delays have increasingly attracted widespread attention [28e30]. In this study, we found that fracture healing time is longer compared with external fixation and intramedullary nail group. External fixation plays an important role in some simple fixation or in patients with severe soft tissue injury, but the fixing strength is insufficient [7,31,32]. External fixators must be maintained until healing has occurred, which can be problematic due to pin or wire site complications [33]. Additionally, other disadvantages, such as fixed needle loosening, pin tract infection, needle around oppressive skin necrosis also limited its widespread use [34]. Our study indicated that the biomechanical characteristics of external fixation are weaker and healing time is longer significantly than intramedullary nailing. The benefits of intramedullary nailing include load sharing, sparing of the extraosseous blood supply, and avoidance of additional soft-tissue dissection, thereby minimizing the risk of postoperative complications [35]. Recently, increasing researchers have begun to focus on intramedullary nailing for TPF. Morandi et al. [36] reported that the lateral percutaneous suprapatellar intramedullary nailing approach in a semi-extended position is an excellent approach for tibial fractures. Feng et al. [10] indicated that intramedullary nailing has good mechanical properties compared with dynamic compression plate, locking compress ion plate and external fixation. Hogel et al. [14] found that locked intramedullary nailing of proximal tibia fractures leads to a stiffer implant-bone construct than plating and no adverse effects were found after nailing. Therefore, they proposed nailing to be a good alternative to plating for tibial plateau fractures, especially in patients with soft tissue problems. In our study, it was confirmed that intramedullary nail had superior biomechanical characteristics of resistance ability of bending, torsional and axial compressive. Moreover, in the present study, callus occurrence and healing time for TPF treatment were shorter than steel plate and external fixator. This is because intramedullary nail is an elastic fixation without compression around the fracture, and slight passive or active physical activity was existed in fracture site, which is conducive to callus formation [37,38]. However, intramedullary nail technique has negative effects of causing infection. In the present study, one case died due to inflammation, which was equal to the other two groups. In conclusion, intramedullary nail has superior biomechanical characteristics in human adults cadaver tibia model of A1 tibial plateau fracture, additionally, better clinical effects in animal experiment than steel plate and external fixator. However, tibial plateau fractures often have a spiral or comminuted component and findings from the A1 model may not address these. Thus, additional plate buttressing may be recommended for stability. More clinical trials are necessary for widespread use of intramedullary nail fixation for tibial plateau fractures treatment. Ethical approval All animal studies have been approved by Central Hospital of Yiwu City Ethics Committee and performed in accordance with the ethical standards. Author contribution
Table 2 Callus appeared time and fracture healing time of rats tibia fixed by three fixation methods (n ¼ 8). Group
Callus appeared time (d)
Healing time (d)
Steel plate External fixator Intramedullary nail
14 ± 1.92** 18 ± 2.47## 12 ± 1.1xx
39 ± 4.73** 48 ± 4.46## 32 ± 3.73xx
**P < 0.01 vs. intramedullary nail group; ## P < 0.01 vs. steel plate group.
xx
P < 0.01 vs. external fixator group;
Hong-wei Chen: study design, data analysis, writing. Guo-dong Liu: study design, data analysis, writing and final approval of the manuscript. Xie-yuan Jiang: data collection, statistical process and photo precess. Jun Fei: data collections, writing statistical process. Li-jun Wu: data collections, writing. All authors have read and approved the manuscript.
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