The Application Of 3D Printing In The Knee Arthroplasty Of The Proximal Tibial Giant Cell Tumor

Objectives:To explore the application of tibial block and knee joint prosthesis in the knee arthroplasty of proximal tibial giant cell tumor of the tibia by 3D printing Methods:Between August 2015 and December 2015,4 patients(1 male and 3 females,aged 35–68 years)with giant cell tumor of the proximal tibia underwent en-block resection of the tumor of the proximal tibia and reconstruction with prosthesis.All 4 cases were diagnosed pathologically with GCT.One case was diagnosed by primary tumor.The other 3 underwent curettage in previous surgery and suffered a local recurrence.One of them(Case 3)underwent internal fixation after curettage.Imaging data of the patient's bilateral knee joints was obtained through 64-slice spiral CT scan(PHILIPS Corporation,Japan)(X-ray Tube Current 232 mA and KVP 120 kV,slice thickness 1 mm,reconstruction interval 1 mm).The DICOM file format obtained by each scan was input into the Materialise's Mimics(version 14.0)software package for 3D reconstruction and editing to eliminate impurities.Results were then saved in the STL file format and imported into the IMAGEWARE software(Imageware V12.1,EDS Corporation,USA)to mimic surgery and design of custom-made proximal tibia block(Figure 3.2)The proximal tibia block was designed through the mirror image of the 3D reconstruction(unaffected side)to ensure the same morphological characters.Then,the length of the block was designed through surgical simulation software according to resection region?After the design was completed,the model was saved as an STL file and then imported into a 3D printing machine.The designed block model,include tibia tray prosthesis with extension stem,was 3D-printed at 1: 1 scale.All these models were made of photosensitive resin.Preoperatively,surgical simulation based on the 3D-printed model was produced to check the accuracy of the model(Figure 3.5).The block combined with proximal tibia prosthesis fitted the tibia precisely during the preoperative surgical simulation through photosensitive resin models.The final product was fabricated by a commercial company(AK MEDICAL Ltd,China),which was certified by China Food and Drug Administration(CFDA).The 3D-printed product was made of titanium alloy(Ti6Al4V)through use of EBM technology.Reticular porous structures were generated on the surface of the block during the process of rapid-prototyping.After post-processing,the block could be used.Results:In this study,the personalized 3D-printed proximal tibia block was successfully applied in treating patients with GCT,acquiring functional results.3D printing technology makes the operation precise and safe,which is beneficial for the patients.The advantage of 3D printing to observe the anatomical structure of the patient is obvious.We use the 3D printing technique to visualize the operation?The use of a 3D print model made of photosensitive resin makes it easier and safer to design the surgical procedure.During the operation,the individualized design of the proximal tibial bone is more convenient for the application of innovative surgical techniques.Benefit from the advantage of 3D printing technology,the block was modified to easily connect the soft tissue of collateral ligaments,which could help reconstruct the knee joint,and is useful in design and manufacture of custom-made orthopedic medical instruments.This new surgical technique could be more widely used because of 3D printing technology 3D printing technology is a kind of additive manufacturing,in which no raw material is wasted,so the cost of 3D printing is lower than in tradition processes.The total cost was about 30% lower than the cost of traditional prosthesis.The time needed to produce a 3D-printed customized prosthesis was also shorter than that required for a traditional prosthesis.Taken together,these facts make this new technology attractive.