| Calcaneal is one of the largest weight-bearing foot bones in human, which plays a very important role in the process of standing and the normal walking. Calcaneal fractures is a common foot fracture, it accounts for about 2% of the whole body bone fracture and 60% of the tarsal bone fractures, also it would achieve as high as 75% at intra-articular fractures. Most Calcaneal fracture is always related to a injury as mature men working by a accidently falling down from high. If calcaneal fractures wouldn’t have a correct treatment, especially intra-articular calcaneal fractures, it may prone to a lot complications what may give patients have long-term foot dysfunction and pain, the morbidity of calcaneal fractures is as high as 30%.While calcaneal fractures is not a high incidence of the whole body fracture, but its high morbidity tends to bring patients and their families a huge pain and burden of life. The last one hundred years, numerous orthopedic surgeons is exploring the treatment of calcaneal fractures, but controversy still exists until today. The value of open reduction and internal fixation have be almost recognized in the treatment of the closed intra-articular displaced calcaneal fractures, but the treatment remains controversial for pen calcaneal fractures. The open calcaneal fracture is accounted for about 4.8% of the total calcaneal fractures in our hospital epidemiology survey. Open calcaneal fractures are related to a high-energy damage, whose treatment purpose is to make a maximize recovery for the foot function, and prevent infection and reduce complications. Along with the development of science and technology, the rising incidence of open calcaneal fractures has also been paid more and more attention by scholars. In recent years, many literatures have reported the prognosis and treatment of open calcaneal fractures at home and abroad, which all shows a characteristic of the high incidence of complications. In many related factors, we couldn’t exactly find that which factors may determine the outcome of open calcaneal fractures, it still remains controversial. We have conducted a large sample retrospective study in order to find the key factor affected outcome of open calcaneal fractures. We make the soft tissue damage degree, the position of open wound, and the fixed way as the related factors which may affect the outcome of open fracture, and we make the statistical analysis from incidence of complications and function of foot by scoring, purposing to find the related factors which do the most profound effect on the prognosis of open calcaneal fractures.Calcaneal and its surrounding tissue anatomy characteristic have determined the high related complications accompanied with the incision whatever we chose, and this problem is still troubling the orthopedic surgeons all around the world. In order to avoid the high risk of complications related to the operative treatment of calcaneal fractures, many scholars are advocating the minimally invasive surgery in the treatment of calcaneal fractures. Minimally invasive treatment of calcaneal fractures has a long history, the earliest can be dated back to 1943, a German doctor first introduced percutaneous prying reduction with Kirschner in sagittal to treat calcaneal fractures, and it is the beginning of minimally invasive treatment. in the following decades, with the development of science and technology, the rapid development of minimally invasive treatment. In recent years, clinical appear a variety of minimally invasive surgery in the treatment of calcaneal fractures. It is mainly consisted of closed reduction and percutaneous screw fixation, small incision micro plate internal fixation, external fixation frame open external fixation, subtalar arthroscopy assisted reduction, percutaneous balloon dilatation and so on. Minimally invasive technology has an obvious advantage in the treatment of calcaneal fractures, not only enriched the treatment, but also reduced the incidence of complications of calcaneal fractures. It has improved the clinical curative effect. We have chosen closed reduction and hollow screw fixation for the treatment of 30 cases Sanders II type and Sanders III type calcaneal fractures, and they all have obtained satisfactory clinical effect. Our research has made a statistical analysis on reduction, waiting time of operation, operation time and postoperative hind foot score after surgery and other respects, and this method is confirmed effective in the treatment of specific calcaneal fracture.The lateral and axial X-ray image, as an fractures diagnostic imaging technology of calcaneus, are commonly used in the diagnosis of calcaneal fractures, surgery reduction and the postoperative curative effect evaluation. B?hler angle and Gissane angle of calcaneus has been widely applied to evaluate the severity of the fracture and the prognosis of calcaneal fracture by orthopedics doctors. Especially in the operation of calcaneus fracture reduction and evaluation, it plays an important role in the operation process. In the operation reduction process, we need to restore the calcaneus length, wid- th, smooth joint surface, B?hler angle and Gissane angle at the same time. Furthermore, we should also pay attention to avoid the calcaneal varus or valgus deformity. There is no study show that the normal calcaneal varus angle range and how to assess calcaneal varus or valgus deformity. We alw- ays judged calcaneal varus or valgus by calcaneal axial X-ray imaging but there is no explicit criterion in current time. We propose a method to measure calcaneal varus angle through standard calcaneus axial X-rayim- age. By this method, we have measured 164 volunteers calcaneal normal varus angle, and the range of normal calcaneal varus angle was obtained, which provide a theoretical basis for clinical work.Finite element analysis is a kind of numerical computation method which carried out by means of computer, and is application and development of matrix method in the field of structural mechanics and elasticity. In the 1970 s, Finite element analysis began to be used in orthopedic biomechanics analysis field. In 1993, Yattram and Camilleri reported Three-dimensional finite element analysis of calcaneus for the first time. With the rapid development of the finite element analysis in decades,it has been widely applied in areas of orthopedics. In our study, we establish the regular Three-dimensional finite element mode of calcaneus and use a program to change the varus angle to establish the modes with different varus angle. With the simulation of 100 N axial pressure respectively, we focus on the pressure distribution on the posterior calcaneal facet. In conclusion, the correlation between the varus angle and the pressure distribution on the posterior calcaneal facet should be discussed to ascertain the range of reduction of varus angle. Part 1 Correlation analysis of the factors effecting outcome of opencalcaneal fracturesObjective: To discuss the effect of soft tissue injury, fixation and the wound location on the outcome and the incidence of complications in open calcaneal fractures, and to identify which factors is the key to the outcome of open calcaneal fractures.Methods: The 101 patients with open calcaneal fractures had been treated in the Third Hospital of Hebei Medical University from 2007 January to 2013 May. All patients had signed the informed consent, and the study had been approved by certification of the ethics committee in our hospital. All open calcaneal fractures were classified according to Gustilo classification: there are 4 cases in Gustilo I, 47 cases in Gustilo II, 50 cases in Gustilo Ⅲtype fractures. According to the different internal fixation methods, all fractures were divided into 4 group: Kirschner wire group(74 cases), open reduction and internal fixation(15 cases), hollow screw group( 7 cases), and casting group(5 cases). All patients were treated with emergency operations. Kirschner wire, hollow screw or plate were used to fix Gustilo type I and II fractures with medial wound in. Gustilo III type fractures were treated with Kirschner wires or hollow screw. The Kirschner wires or hollow screws were used for the fractures with lateral wound but not plate fixation. Three experienced orthopedics doctors were in charge of checking hind foot function and making the questionnaire surveys for the 101 patients at the last follow-up. We evaluate the postoperative function of the patients according to the AOFAS. We need observe and record that wound change, such as infection(superficial infection or deep infection), whether need the second operation to make skin grafting or flap to cover the wound or not. By this way, we can evaluate the incidence of complications.Results: All open calcaneal fractures of 101 patients were followed up for average 38.4months(8-78 months). The overall infection rate was 22%. According to AOFAS, 16 cases were excellent(15.8%), 42 cases were good(41.6%), 31 cases were medium(30.7%) and 12 cases were poor(11.9%).The functional score between the different internal fixation group was no statistically significant difference(P>0.05). The incidence of complications between the different fixation group was no statistically significant difference too(P > 0.05).However, the complication rates between the different Gustilo groups had a significant difference(P <0.05).All through there was no statistically significant difference between Gustilo type I group and Gustilo type II group in the AOFAS score, but between the Gustilo I group and Gustilo III group, Gustilo II group and Gustilo III group, there are significant different in score of ankle and hind foot(P <0.05). There is no significant difference between the medial wound group and the lateral wound group in e complication rates and score of ankle and hind foot(P > 0.05).Conclusion: The outcome of the open calcaneal fractures depends on the degree of the soft tissue injury but not the fracture fixation method. There is no significant correlation between outcome and wound location. The early completely soft tissue debridement and timely reasonable fracture fixation are the key to reduce the incidence of complications and improve the clinical effect. So emergency debridement accompanied with fracture fixation is an effective method for the treatment of open calcaneal fractures. Part 2 Clinical study of closed reduction and cannulated screw fixationfor Sanders II and Sanders III type fracturesObjective: The aim of this study was to evaluate the efficacy of closed percutaneous poking reduction by Kirschner wire and cannulated screw fixation for treatment of Sanders II and III type calcaneal fractures with no severe widened deformity in clinical.Methods: Thirty patients who matched the criteria of entering the group of calcaneal fractures had been managed in trauma emergency center of our Hospital(This study has been approved by the Ethics Committee of the Third Hospital of Hebei Medical University). There are 24 cases in Sanders type II group and 6 cases in Sanders type III group. All patients were treated with closed reduction and cannulated screw fixation. All patients received follow-up by imaging and functional evaluation.Results: All patients received 3 months(6-12 months) follow-up. No deep infection or nonunion or delayed wound healing happened according to follow-up, only two cases accompanied with the Kirschner tail irritation, the symptoms disappeared after the removal of Kirschner; The average operative waiting time was 3.9 days(1-6 days), and the average operating time was 34.8 minutes(25-49 minutes).The average B?hler angle was 14.7 degrees preoperative, and 33.0 degrees postoperative, there was an statistically significant differences(P<0.05) between the preoperative and the postoperative in B?hler angle. The average Gissane angle was 102.4 degrees preoperative, and 118.8 degrees postoperative, there was an statistically significant differences(P<0.05) between the preoperative and postoperative in Gissane angle. In the subjective AOFAS score of All patients, 18 cases were excellent(60%), and 12 cases were good(40%). The dorsiflexion and plantar flexion activity of ankle in fracture side has no significant difference compared with the healthy side(P <0.05).Conclusion: For the treatment of the intra-articular calcaneal fractures of the Sanders II and Sanders III type, especially tongue-shaped fractures, closed reduction and cannulated screw fixation have a lot advantages, such as less trauma; not stripping soft tissue around calcaneal, which may reduce the incidence of complications of calcaneal fracture; simple and easy; short waiting time before the operation and operation time; good postoperative recovery and so on. So it is a more appropriate choice for treatment of some specific calcaneal fracture. Part 3 Measuring of the normal calcaneal varus angle and three-dimensional finite element analysisObjective: to measure the normal calcaneal varus Angle and analysis equivalent stress changes of calcaneal posterior joint surface when calcaneal varus Angle changed by use of three-dimensional finite element technology, to discuss the clinical significance of calcaneal varus Angle. Methods: Standard calcaneal axial X-ray images of 165 volunteers were imported to the computer, to measure the size of the normal calcaneal varus Angle by use of Photoshop software. Measurement method: Draw vertical of calcaneal posterior joint surface through the narrowest place of inside wall, the joint surface intersection point marked as point A, the narrowest point of calcaneal medial wall marked as point B, and the most medial point of posterior calcaneal marked as point C, The intersection Angle of line AB and line AC is the calcaneal varus angle. Calcaneal CT images of 1 volunteers was imported to Mimics 14.0 software for preparation of model, and Creo 2.0 three dimensional modelling software was used for preparation of calcaneal models with different varus angle. All models were simulated calcaneal in the neutral position, so calcaneal head and the bottom of the calcaneal were set as constraint boundary conditions. Axial power(the Z axis load) loaded on joint surface of the model, and joint surface was endued same material properties with compact bone. So, load power was exerted on joint surface more uniform. 100 N force loaded on the calcaneal posterior joint surface, and images of equivalent stress distribution calcaneal models with different varus angle were obtained.Results: The average normal calcaneal varus Angle is 3.99 degrees in our study. Images of equivalent stress distribution calcaneal models with different varus angle after simulation load show: 100 N loading on calcaneal model in neutral position, stress distribution on the calcaneal posterior articular surface is uniform, stress concentration area appears in the anterior lateral articular surface, and maximum of stress value is 11.46 Mpa; In the model of varus angle increased 2 degrees, stress distribution appeared in anterior and lateral of articular surface, there are several stress concentration areas in anterior and lateral, and the maximum stress value is 4.9 Mpa; When varus angle increase 4 degrees, stress distribution located in medial of articular surface, the stress concentration area appears in the center of articular surface anterior, and the maximum stress value of 7.6 Mpa; stress distribution and maximum stress location in model of varus angle increasing 6 degrees are same to that in model of varus angle increasing 4 degrees, but the maximum stress value is 8.0 Mpa; When varus angle reduce 2 degrees, stress distribute in anterior medial of articular surface, the stress concentration area appears in the center of articular surface anterior, and the maximum stress value is 5.7 Mpa; In model of varus angle reducing 4 degrees, stress distribute in anterior medial of articular surface, the stress concentration area appears in posterior medial of articular surface, and the maximum stress value is 106.3 Mpa; When varus angle reduce 6 degrees, stress distribute in medial of articular surface, the stress concentration area appears in anterior medial and posterior medial of the articular surfaces, and the maximum stress value is121.6 Mpa.Conclusion: In the surgical treatment of intra-articular calcaneal fractures process clinically, we not only need to restore the calcaneus length, width, joint surface smooth, B?hler angle and Gissane angle, but also restore the calcaneal varus angle. We suggest that the calcaneal varus angle should not decrease more than 2 degree, if varus angle become too small, the stress distribution on the calcaneal posterior joint surface will change significantly, and subtalar arthritis and other complications may occur later period. |
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