## 1 Introduction
First, the STL file from the CAD model of an object is imported to the slicer software to set up all the necessary printing parameters, such as printing speed, nozzle temperature, layer height and the generation of the G-code for communication with the 3D printer. In FDM, the raw material is pushed out through a nozzle while pressure is applied. In this process, a spool of thermoplastic filament must be melted and extruded through a high-temperature nozzle. The layers used in the additive production process are created by extruding molten material onto the substrate. It is necessary to bind the material with previous material in order to produce a solid component. In the FDM process, different thermoplastic materials (such as acrylonitrile butadiene styrene (ABS), nylon, polylactic acid (PLA) and polycarbonate) can be used [14]. The 3D printing technique not only enables the fabrication of complex structures in a timely and cheap manner but also allows for the manufacture of composites with various combinations of compositions [15]. The literature review of the 3D printing techniques used in medicine is presented below. [PERSON] et al. [16] proposed an innovative clamp design that utilizes fairly recently available technology (i.e., 3D printing) to produce a made-to-measure tendon sleeve that encloses the sample ends and also enables straightforward alignment within the testing equipment. All experiments were carried out using the superficial digital flexor tendons obtained from the hind pig legs. The sleeve was designed in such a way as to reduce slippage by introducing perfectly interlocking serrations. This has the advantage of evenly distributing the pressure on the tendon, thereby reducing the risk of stress concentration. In the paper presented by [PERSON] et al. [17], the authors used quasistatic tensile tests combined with digital image correlation and fatigue trials to characterize the applicability of the current clamping technique using 3D printed clamps. They reported that the 3D printed clamps showed no signs of clamping-related failure during the quasistatic tests and the fatigue tests and that the material slippage was low. A comparison to other clamping techniques shows that the 3D printed clamps ease and expedite specimen handling, are highly adaptable to the varying specimen geometries and are ideal for high-standardization and high-throughput experiments in soft tissue biomechanics. They used a clamp design with 4-sided pyramid structures in a cross-sectional view. For all 3D prints, the parts were produced with 100-micron layers using a 0.4 mm brass nozzle. The clamps were printed in an upright position in order to produce a lateral orientation of the pyramids, allowing for these surface structures to have a very detailed quality. The material used for the clamps' 3D printing was polylactic acid (PLA). Furthermore, in another paper [18] from the same authors, the standardized tensile testing procedure using a 3D printed clamping system used in [17] was presented. In addition, the following examples show that the application of 3D printing technology is not new to medicine and it is not limited to one specific area of interest. However, due to its accessibility, it is significantly useful in helping to understand the human body in general. In [19] it was used for the 3D printing of a titanium periacetabular implant with horseshoe-shaped plates, in [20] to depict organ-tumor relations and even possibly used for control-based 4D printing in medicine in [21]. What follows are some relevant issues related to FDM printing: visible layer lines, poor part strength, nozzle radius limits, high surface roughness, temperature fluctuation issues, support material and structure [14]. The background of this work is dealing with medial patellofemoral ligament (MPFL) injury, classified as a dislocation of the patella. It is emphasized that this injury occurs, on average, for 5.8 per 100,000 persons per year, and that number is growing (it is as high as 29 in 100,000 people between 10 and 17 years of age).