Endoscopic Treatment of Symptomatic Foot and Ankle Bone Cyst with 3D Printing Application

Carpal bone replacement using personalized 3D printed tantalum prosthesis

Objective: Scaphoid and lunate fractures have a relatively high incidence rate. Traditional carpectomy and carpal arthrodesis in the treatment of carpal osteonecrosis will lead to many complications. Three-dimensional (3D) printed tantalum has good biocompatibility and can be designed to match the patient's personalized anatomical carpal structure. This study aims to investigate carpal function and prosthesis-related conditions after carpal bone replacement using 3D printed tantalum prostheses. Methods: From July 2020 to January 2022 at our center, seven patients with osteonecrosis of the carpus received carpal bone replacement using 3D printed tantalum prosthesis. The Disability of the Arm, Shoulder and Hand (DASH) score and patient satisfaction, as well as the Mayo Wrist Scores (Cooney method, modified Green, and O'Brien wrist score), were used to evaluate the preoperative and postoperative wrist function of patients. The Visual Analog Scale (VAS) pain scores were also recorded before and after surgery. The angles of flexion, dorsiflexion, ulnar deviation, and radial deviation were measured using an arthrometer. The grip strength and pinch strength of the operated hand after carpal bone replacement and the contralateral healthy carpus were measured using a dynamometer. Radiographs were taken to confirm the condition and complications of the tantalum prosthesis. Results: All seven patients were followed for 19.6 ± 2.7 months. At the last follow-up, the grip strength of the operated wrist joint after carpal bone replacement was 33.4 ± 2.3 kg, the pinch strength was 8.9 ± 0.7 kg, the flexion was 54.6° ± 0.8°, the dorsiflexion was 54.7° ± 1.7°, the ulnar deviation was 34.6° ± 1.9°, and the radial deviation was 25.9° ± 0.8°, all of which showed no statistically significant difference with the contralateral healthy carpus (p > 0.05). There were significant differences in the VAS, DASH, and MAYO scores between the preoperative and the last follow-up (p < 0.01). Patients had reduced postoperative pain and improved wrist function and range of motion (ROM), and the tantalum prostheses were stable. Conclusion: The 3D printed tantalum brings us new hope, not only for hip or knee replacement, but also for joint replacement of other complex anatomical structures, and patients with other irregular bone defects such as bone tumors and deformity, which could realize personalized treatment and precise medicine.

An overview of 3D printed metal implants in orthopedic applications: Present and future perspectives

With the ability to produce components with complex and precise structures, additive manufacturing or 3D printing techniques are now widely applied in both industry and consumer markets. The emergence of tissue engineering has facilitated the application of 3D printing in the field of biomedical implants. 3D printed implants with proper structural design can not only eliminate the stress shielding effect but also improve in vivo biocompatibility and functionality. By combining medical images derived from technologies such as X-ray scanning, CT, MRI, or ultrasonic scanning, 3D printing can be used to create patient-specific implants with almost the same anatomical structures as the injured tissues. Numerous clinical trials have already been conducted with customized implants. However, the limited availability of raw materials for printing and a lack of guidance from related regulations or laws may impede the development of 3D printing in medical implants. This review provides information on the current state of 3D printing techniques in orthopedic implant applications. The current challenges and future perspectives are also included.

3D Printing-Assisted Supramalleolar Osteotomy for Ankle Osteoarthritis

Ankle osteoarthritis (OA) is an important factor that causes pain and dysfunction after ankle joint movement. In early and mid-term ankle OA, supramalleolar osteotomy can delay the progression of disease and maximize the preservation of ankle joint function. Three-dimensional printing (3DP) technology has brought us new hope, which can improve the accuracy of osteotomy, reduce the number of fluoroscopy, reduce the amount of blood loss, and achieve personalized and accurate treatment. The data of 16 patients with ankle OA in our center from January 2003 to July 2020 were retrospectively analyzed and divided into the 3DP group and the traditional group according to different treatment methods. Seven patients in the 3DP group used the 3DP personalized osteotomy guide; nine patients were treated by traditional osteotomy. All patients were followed up for 13.9 ± 3.1 months after the operation. The operation time in the 3DP group was 126.4 ± 11.1 min, its intraoperative blood loss was 85.7 ± 24.1 mL, and its intraoperative fluoroscopy time was 2.4 ± 0.2, which were all significantly less than 167.3 ± 12.2 min, 158.3 ± 22.8 mL, and 5.8 ± 0.2 times in the traditional group (P < 0.05), respectively. In the 3DP group, its postoperative tibial anterior surface (TAS) angle was 90.6 ± 0.3° and the talar tilt (TT) angle was 2.2 ± 0.6°, which were all significantly different compared with its preoperative data of 83.4 ± 1.7 and 8.0 ± 1.5°, respectively (P < 0.05). Compared with traditional osteotomy, 3DP-assisted supramalleolar osteotomy for varus and valgus ankle OA can significantly shorten the operation time and reduce intraoperative bleeding and the frequency of intraoperative fluoroscopy; personalized 3DP osteotomy guides and models can assist in the accurate correction of varus deformity during operation, restore the lower limb alignment, and improve the biomechanical status of the lower limbs. In addition, the 3DP of porous tantalum has good histocompatibility, and its interface structure and porosity are more conducive to bone ingrowth. For complex bone defects and revision prostheses, matching implants can be printed individually, which could realize the personalized precise treatment.

Preoperative Planning Using 3D Printing Technology in Orthopedic Surgery

The applications of 3D printing technology in health care, particularly orthopedics, continue to broaden as the technology becomes more advanced, accessible, and affordable worldwide. 3D printed models of computed tomography (CT) and magnetic resonance image (MRI) scans can reproduce a replica of anatomical parts that enable surgeons to get a detailed understanding of the underlying anatomy that he/she experiences intraoperatively. The 3D printed anatomic models are particularly useful for preoperative planning, simulation of complex orthopedic procedures, development of patient-specific instruments, and implants that can be used intraoperatively. This paper reviews the role of 3D printing technology in orthopedic surgery, specifically focusing on the role it plays in assisting surgeons to have a better preoperative evaluation and surgical planning.

Management of Bone Cyst of Talar Body by Endoscopic Curettage, Nanofracture, and Bone Graft Substitute

Large bone cyst of the talar body is frequently associated with an osteochondral lesion. The talar bone cyst can be an incidental radiologic finding. However, when the talus is extensively destroyed, there is a risk of pathologic fracture and damage to the articular cartilage, leading to persistent swelling and pain of the subtalar joint and ankle joint. Open debridement and bone grafting frequently requires extensive soft-tissue dissection or even different types of malleolar osteotomy for proper access to the lesion. The purpose of this Technical Note is to describes the technique of endoscopic curettage, nanofracture, and filling the cyst with injectable bone graft substitute. This minimally invasive approach has minimal disruption of the normal cartilage surface.