For decades, open reduction and internal fixation performed by an extended extensile lateral approach has been the standard treatment for calcaneal fracture [19]. With this treatment, a certain degree of anatomical reduction is achieved, but the occurrence of serious complications has gained surgeons’ attention and resulted in the development of a minimally invasive approach [20]. In recent years, with the efforts of scholars, minimally invasive surgery has become a more effectively surgical method solve calcaneal fractures. Nosewicz et al [21] reported sufficient exposure of complex calcaneal fractures by application of a minimally invasive sinus tarsi approach for anatomic reduction and stable fixation. Wang et al [22] applied a minimally invasive lateral approach in 156 patients and found that the percutaneous leverage, manual compression, and application of anatomic plates and compression bolts to be effective for displaced intra-articular calcaneal fractures, offering a combination of fewer soft tissue complications and good reduction.
But the classical minimally invasive surgical method for calcaneal fractures still has some disadvantages. The classical method includes fracture reduction, temporary fixation and internal fixation implantation. On the one hand, almost all of the above surgical procedures require a lot of intraoperative fluoroscopy. On the other hand, the surgeons determine the procedure at each step of the operation all depend on the surgeon's experiences and are often not optimal.
The minimally invasive surgery varies according to the fracture pattern. This makes personalized surgical planning important [23]. With the help of CT imaging and a rapidly produced prototype, surgeons can obtain detailed information regarding the fracture and use software to plan a procedure that will result in suitable fixation [24]. More importantly, the surgery can be simulated in vitro. Although preoperative planning is often near-perfect, it is not possible to fully anticipate the surgical challenges of individual cases. The calcaneus fracture type is complex [25], and there is no single treatment protocol that covers the various kinds of calcaneal fracture. The core point of the PSI was to guide the surgery as planned. we digitally reconstructed the calcaneus on the computer so that we could understand the characteristics of the fracture [26], second, simulating the reduction and fixation, then creating a PSI and using it to guide the actual surgery.
Our team intends to optimize the classical calcaneal fracture minimally invasive internal fixation into a more personalized and precision operation method. Therefore, we have creatively designed an optimal surgical procedure through the digital surgical simulation, and then we manage the operation through the assistance of PSI during the whole process. Combined with the cases in this paper, we preliminarily believe this new surgery method is great different from the classical minimally invasive calcaneal fractures surgery.
What is unique about this new case we reported is that the traditional calcaneal fracture minimally invasive internal fixation procedure was changed to: preoperative digital surgical simulation and preparation of PSI, install Schanz pins (or K-wires) by using PSI, adjustment of the relationship between Schanz pins (or K-wires) and PSI according to the surgical plan, internal fixation implantation by using PSI. In fact, we changed the operation procedure from traditional “focusing on internal conditions” to new “focusing on external auxiliary tools”, so as to optimize the surgery into a new surgical method that is more directly, faster and more accurate.
This paper not only shows a new PSI, but also shows an unprecedented new method for calcaneal fracture internal fixation. In other words, the whole process of the operation assisted by PSI, and performed the preoperative plan step-by-step, which is different from the traditional surgery method fundamentally. In fact, The steps of traditional method are improvisational, surgical procedures have some uncertainty. However, our new method of this study is standardized and relatively step-by-step. In addition, our new method is also very different from the traditional PSI method, which only optimizes a part of procedure, while our new method can improve the whole operation process, or even make transformation of the operation. Based on this case, we found that the new operation method was very simple and the surgery process was smooth, the operation time was less than half of the classic operation, and the postoperative effect was also very good. With the assisted by PSI in whole process, the operation was guided at every step, surgical procedures became routine, intraoperative fluoroscopy was no longer required at every step, fracture reduction and internal fixation became relatively perfect. Therefore, it can be preliminarily believed that such a new type of technology will be expected to optimize the traditional surgical scheme greatly.
Strengths and limitations of the study
Still, there are some limitations of this new method. First, designing the PSI is a complex procedure [27, 28]. Though it doesn’t take much time to make it, the surgeon needs a technologist who is skilled at the Mimics software to assist to make the PSI. If the surgeon is good at the software, that won’t be a problem. Second, the system also cannot be used to manage an old fracture. We just use the Schanz pins (or K-wires) to reduce fracture, fresh fracture is easy to reduce while the old fracture can’t be reduced with closed reduction. Typically, we think it is best to conduct the PSI assisted surgery within 8 hours after injured. Third, this is preliminary application with the small number of sample sizes and short period of follow-up. Therefore, further prospective investigations with the large numbers of sample sizes and longer follow-up duration will be necessary to investigate appropriate values for clinical application.