The Validity and Accuracy of 3D-printed Patient-specific Instruments for High Tibial Osteotomy: A Cadaveric Study

Objective High tibial osteotomy (HTO) has been used for the treatment of patients with knee osteoarthritis. However, the successful implementation of HTO requires precise intraoperative positioning, which places greater requirements on the surgeon. In this study, we aimed to design a new kind of 3D-printed patient-specific instrument (PSI) for HTO, including a positioning device and an angle bracing spacer, and verify its effectiveness using cadaveric specimens.Methods This study included ten fresh human lower limb cadaveric specimens. Computed Tomography(CT) and X-ray examinations were performed to make preoperative plans. PSI was designed and 3D-printed according to the preoperative plan. Then, the PSI was used to guide HTO. Finally, we performed X-ray and CT after the operation to verify its validity and accuracy.Results The PSI use process was adjusted according to the pre-experimental procedure in 1 case. Hinge fracture occurred in 1 case. According to X-rays of the remaining 8 cadaveric specimens, no statistically significant difference was noted between the preoperative planning medial proximal tibial angle (MPTA) and postoperative MPTA (P > 0.05) or the preoperative and postoperative posterior slope angle (PSA) (P > 0.05). According to the CT of 10 cadaveric specimens, no statistically significant difference was noted between the design angle and actual angle, which was measured according to the angle between the osteotomized line and the cross-section (P > 0.05). The gap between the designed osteotomy line and the actual osteotomy line was 2.09(0.8~3.44) mm in the coronal plane and 1.58(0.7~2.85) mm in the sagittal plane.Conclusion This 3D-printed PSI of HTO accurately achieves the angle and position of the preoperative plan without increasing the stripping area. However, its use still requires a certain degree of proficiency to avoid complications, such as hinge fracture.

HURWA Robotic-Assisted TKA System is Suitable for a Variety of Prosthesis Types

Background Total knee arthroplasty (TKA) is an effective and also mature surgical interventions that improves life quality and provides pain relief. Accurate bone cuts are important to prevent TKA malalignment and it requires cautious preoperative plan and precise bone resection. Recently, robotic-assisted TKA techniques have been used to improve the accuracy of bone resection and implantation. However, the system described above suits for only one prosthesis type. Methods Five types (MicroPort_CS, Smith& Nephew_GII, Johnson&Johnson_PFC_PS, kingnow _VLQX_PS and Akmedical_A3GT_PS) implants were included in our study and three Sawbones models were used for each implant. Procedures were performed by experienced joint replacement surgeons using HURWA robotic-assisted TKA system. Results our study indicated that the bone resection error of HURWA robotic-assisted system was below 0.5 mm (with SDs below 0.3 mm), and all of the bone resection angles were below 0.5° (with SDs below 0.3°). The bone resection angles and levels deviation of different brand prosthesis types were below 0.5 mm (with SDs below 0.3 mm) and below 0.5° (with SDs below 0.3°) respectively. Conclusion It suggested that our system may be suitable for different prosthesis types.

Current Concepts in Humeral Component Design for Anatomic and Reverse Shoulder Arthroplasty

The history of humeral component design has evolved from prostheses with relatively long stems and limited anatomic head options to a contemporary platform with short stems and stemless implants with shared instrumentation and the ability to provide optimal shoulder reconstruction for both anatomic and reverse configurations. Contemporary humeral components aim to preserve the bone, but they are potentially subject to malalignment. Modern components are expected to favorably load the humerus and minimize adverse bone reactions. Although there will likely continue to be further refinements in humeral component design, the next frontiers in primary shoulder arthroplasty will revolve around designing an optimal plan, including adequate soft tissue tension and providing computer-assisted tools for the accurate execution of the preoperative plan in the operating room.

Preoperative considerations for peripheral nerve stimulation of the sacroiliac joint

This chapter reviews preoperative factors to be considered before performing peripheral nerve stimulation of the sacroiliac joint. When designing a preoperative plan, it is important to consider the type of anesthesia to be administered, anticoagulation management, infection risk, and other relevant medical comorbidities that may complicate the procedure. These factors vary depending on the patient, and in many cases coordination with other specialists is required. Optimization of patient comorbidities, appropriate management of anticoagulation, and planning strategies to minimize infection risk (including the use of perioperative antibiotics) are paramount to ensure the best possible outcomes for the patient undergoing this procedure.

An image fusion system for corrective osteotomy of distal radius malunion

Background To provide surgical support for corrective osteotomy, we developed an image fusion system for three-dimensional (3D) preoperative planning and fluoroscopy. To assess the utility of this image fusion system, we evaluated the reproducibility of preoperative planning for corrective osteotomy of dorsally angulated distal radius malunion using the system and compared reproducibility without using the system. Methods Ten wrists from 10 distal radius malunion patients who underwent corrective osteotomy were evaluated. 3D preoperative planning and the image fusion system were used for the image fusion group (n = 5). Only 3D preoperative planning was used for the control group (n = 5). 3D preoperative planning was performed for both groups in order to assess reduction, placement, and the choice of implants. In the image fusion group, the outline of the planned image was displayed on a monitor and overlapped with fluoroscopy images during surgery. Reproducibility was evaluated using preoperative plan and postoperative 3D images. Images were compared with the 3D coordinates of the radial styloid process (1), the volar and dorsal edges of the sigmoid notch (2) (3), and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points. Results The distances between preoperative planning and postoperative reduction in the image fusion group were 2.1 ± 1.1 mm, 1.8 ± 0.7 mm, 1.9 ± 0.9 mm, and 1.4 ± 0.7 mm for reference points (1), (2), (3), and the barycenter, respectively. The distances between preoperative planning and postoperative reduction in the control group were 3.7 ± 1.0 mm, 2.8 ± 2.0 mm, 1.7 ± 0.8 mm, and 1.8 ± 1.2 mm for reference points (1), (2), (3), and the barycenter, respectively. The difference in reference point (1) was significantly smaller in the image fusion group than in the control group (P < 0.05). Conclusion Corrective osteotomy using an image fusion system will become a new surgical support method for fracture malunion. Trial registration Registered as NCT03764501 at ClinicalTrials.gov.

Failure of Internal Fixation of The Anterior Ring For Unstable Pelvic Fractures, The Experience of A Single Institute

Background: This study aimed to share our experience of anterior ring fixation failure for unstable pelvic fractures and propose corresponding treatment strategies. Materials: From January 2009 to December 2018, 93 patients with pelvic fractures were retrospectively reviewed. Patients with failure of the anterior ring internal fixation within 3 months after initial surgery were analyzed. Quality of reduction was evaluated using the Majeed scoring system.Results: According to the Tile classification of fracture, there were 23 cases of type B1, 17 cases of type B2, 11 cases of type B3, 28 cases of type C1, 6 cases of type C2, and 8 cases of type C3. The duration from injury to pelvic internal fixation ranged from 5-28 days. Seven out of 93 patients experienced failure of internal fixation of the anterior pelvic ring within 3 months, including 2 patients fixed with an external fixator and 5 patients were fixed with a plate. Five patients undergoing revision surgery were followed up for 6-36 months with an average of 18 months. According to Majeedscore at the last follow-up, there were 2 cases of excellent, 2 cases of good, 1 case of fair, and the excellent and good rate reached 80%.Conclusion: The treatment of complicated unstable pelvic fractures requires early multidisciplinary cooperation, proper management of hemodynamic stability and other comorbidities, and performing internal fixation surgery within 2 weeks. It is necessary to make a preoperative plan and stabilize the posterior ring first, avoiding a single steel plate crossing the pubic symphysis.

Quantitative and individualized assessment of the learning curve in preoperative planning of the acetabular cup size in primary total hip arthroplasty

Introduction The aim of the present study was to investigate the learning curves of 2 trainees with different experience levels to reach proficiency in preoperative planning of the cup size based on learning curve cumulative summation (LC-CUSUM) statistics and a cumulative summation (CUSUM) test. Materials and methods One-hundred-twenty patients who had undergone primary total hip arthroplasty with a cementless cup were selected. Preoperative planning was performed by an experienced orthopedic surgeon. Trainee 1 (student) and trainee 2 (resident) planned the cup size. The trainees were blinded to the preoperative plan and the definitive cup size. Only after a cup size was chosen, the trainees were unblinded to the preoperative plan of the surgeon. LC-CUSUM was applied to both trainees to determine when proficiency in determining the appropriate cup size was reached. A CUSUM test was applied to ensure retention of proficiency. Results With reference to the preoperative plan of the surgeon, LC-CUSUM indicated proficiency after 94 planning attempts for trainee 1 and proficiency after 66 attempts for trainee 2, respectively. Trainee 1 and 2 maintained proficiency thereafter. With reference to the definitive cup size, LC-CUSUM did not signal competency within the first 120 planning attempts for trainee 1. Trainee 2 was declared competent after 103 attempts and retained competency thereafter. Conclusions LC-CUSUM/CUSUM allow for an individualized, quantitative and continuous assessment of planning quality. Based on LC-CUSUM statistics, the two trainees of this study gain proficiency in planning of the acetabular cup size after 50–100 attempts when an immediate feedback is provided. Previous experience positively influences the performance. The study serves as basis for the medical education of students and residents in joint replacement procedures.

Using 3D Printing for Pre-planning of Orthopedic Surgeries, a Review

Background: Recent developments in 3D printing have gave orthopedic surgeons among a novel technology that has the ability to revolutionize preoperative planning. The appearance of 3D printing technology (3DPT) enables the digital preoperative plan & simulation to move from the virtual phase to the reality phase. Numerous fields of medicine are lately benefiting from the operate of 3D printing, including the arising part of 3D printing in orthopedic surgery. Methods: We searched on PubMed and Google Scholar databases in January 2020 to find papers and studies about using 3D printing in orthopedy for aim of preplanning. The key words for search were (“3D printing” OR “3D-printed Model” OR “three-dimensional Printer”) AND (“Orthopedy” OR “Orthopedics” OR “Orthopedics”) AND (“Surgery” OR “Operation”) AND (“Pre-planning” OR “Plan”) AND (“Fracture” OR “Trauma”) that we used compound. We exclude the papers which their titles or abstracts were not relevant. At last, we select the most related papers to use in this article. Results: The search on PubMed found 80 Papers and on Google Scholar found 104 papers. After excluding similar and unrelated papers, 44 papers were selected for this review article. Conclusion: Almost all studies have shown us that using a 3D model can have a very positive effect on the surgical process and its outcomes, as well as patient and surgeon satisfaction. Therefore, we anticipate that this technology will be used in many orthopedic surgeries in the near future.

Three-dimensional evaluations of preoperative planning reproducibility for the osteosynthesis of distal radius fractures

Background Three-dimensional preoperative planning was applied for the osteosynthesis of distal radius fractures. The objective of this study was to evaluate the reproducibility of three-dimensional preoperative planning for the osteosynthesis of distal radius fractures with three-dimensional reference points. Methods Sixty-three wrists of 63 distal radius fracture patients who underwent osteosynthesis with three-dimensional preoperative planning were evaluated. After taking preoperative CT scans of the injured wrists, 3D images of the distal radius were created. Fracture reduction, implants choices, and placements simulation were performed based on the 3D images. One month after the surgery, postoperative CT images were taken. The reproducibility was evaluated with preoperative plan and postoperative 3D images. The images were compared with the three-dimensional coordinates of radial styloid process, volar and dorsal edges of sigmoid notch, and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points. The reproducibility of radial inclination and volar tilt on three-dimensional images were evaluated by intra-class correlation coefficient (ICC). Results The distances between the preoperative plan and the postoperative reduction for each reference point were (1) 2.1±1.3 mm, (2) 1.9±1.2 mm, and (3) 1.9±1.2 mm, respectively. The distance between the preoperative plan and postoperative reduction for the barycentric coordinate was 1.3±0.8 mm. ICCs were 0.54 and 0.54 for the volar tilt and radial inclination, respectively (P<0.01). Conclusions Three-dimensional preoperative planning for the osteosynthesis of distal radius fracture was reproducible with an error of about 2 mm for each reference point and the correlations of reduction shapes were moderate. The analysis method and reference points may be helpful to understand the accuracy of reductions for the three-dimensional preoperative planning in the osteosynthesis of distal radius fractures. Trial registration Registered as NCT02909647 at ClinicalTrials.gov

Puncture and Dose Accuracies of Navigation-Assisted 3D-Printing Templates Combined with Computed Tomography Guided Radioactive Iodine-125 Seed Implantation in the Treatment of Malignant Tumors

Objective: To preliminarily verify the accuracy of navigation-assisted seed implantation by comparing preoperative and actual differences in puncture characteristics and dosimetry in computed tomography-guided, navigation-assisted radioactive iodine-125 seed implantation using 3D-printed templates for the treatment of malignant tumors. Methods: A total of 27 tumor patients who were treated with seed implantation under combination guidance in our hospital between December 2018 to December 2019 were enrolled in this study. Navigation needles (n=1–3) were placed in each patient to obtain preoperative and intraoperative puncture information, including angle, depth, insertion point, and tip position; we also investigated the dosimetry parameters in the preoperative and postoperative plans, including D90, V100, V150, V200, minimum peripheral dose (MPD), conformal index, external index, and homogeneity index of the target area. The t-tests and nonparametric correlation tests were used for analysis (P<0.05 was considered significant). Results: The means errors of the angle, depth, insertion point, and tip position were 0.47 ± 0.521°, 0.35 ± 0.238 cm, 1.7 ± 0.99 mm, and 3.1 ± 1.75 mm, respectively. There were no significant differences between the intraoperative and preoperative angles (P = 0.271), but there was a significant difference in depth (P = 0.002). Errors of the angle, depth, and insertion point were larger for the pelvic/retroperitoneal area than for the head and neck/chest wall (P < 0.05). With the exception of MPD, there was no significant difference in dosimetry indices between the postoperative and preoperative plans (P > 0.05). The MPD in the postoperative plan was higher than that in the preoperative plan (mean: 72.1 Gy and 63.8 Gy, respectively; P < 0.05). Conclusion: Seed implantation under combination guidance showed good accuracy, and the actual intraoperative puncture information and postoperative doses were in good agreement with those in the preoperative plan, thereby demonstrating promising prospects for further development.