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Purpose Medial closing-wedge distal femoral osteotomy (MCWDFO) was used to treat valgus knee malalignment combined with lateral compartment disease. The clinical outcome of the osteotomy depends on the accurate correction of valgus malalignment. The aim of this study was to evaluate the accuracy of a MCWDFO assisted by three-dimensional (3D)-printed cutting guides and locking guides. Patients and methods Thirty-three consecutive patients (33 knees) were operated on using the same MCWDFO. 3D-printed cutting guides and locking guides were used to locate the osteotomy cut plane and to facilitate closing the wedge in 12 patients (3D-guide group). Another 21 patients (conventional group) underwent MCWDFO following the conventional technique. The desired correction was defined as a weight-bearing line (WBL) coordinate 50% of the width of the tibial plateau from the medial tibial margin. The deviation between the planned and executed WBL coordinate, surgical time and fluoroscopic time were compared. Results The mean deviation between the planned and executed WBL coordinate was 4.9% in the 3D-guide group and 7.6% in the conventional group ( P  = 0.024). Shorter surgical time was found in the 3D-guide group (mean, 77.7 minutes vs. mean, 96.5 minutes; P  < 0.001), while the mean number of intra-operative fluoroscopic images was 6.1, compared with 34.7 in the conventional group ( P  < 0.001). Conclusion The use of 3D-printed cutting guides and locking guides can increase the precision of the MCWDFO in patients with lateral compartment disease and valgus deformity, making our surgery more efficiency and occupying less fluoroscopic time.

PurposeUtilization of 3D-printed patient-specific surgical guides is a promising navigation approach for orthopedic surgery. However, navigation errors can arise if the guide is not correctly positioned at the planned bone location, compromising the surgical outcome. Quantitative measurements of guide positioning errors are rarely reported and have never been related to guide design and underlying bone anatomy. In this study, the positioning accuracy of a standard and an extended guide design with lateral extension is evaluated at different fitting locations (distal, mid-shaft and proximal) on the volar side of the radius.MethodsFour operators placed the surgical guides on 3D-printed radius models obtained from the CT scans of six patients. For each radius model, every operator positioned two guide designs on the three fitting locations. The residual positioning error was quantified with a CT-based image analysis method in terms of the mean target registration error (mTRE), total translation error ( ΔT ) and total rotation error ( ΔR ) by comparing the actual guide position with the preoperatively planned position. Three generalized linear regression models were constructed to evaluate if the fitting location and the guide design affected mTRE, ΔT and ΔR .ResultsmTRE, ΔT and ΔR were significantly higher for mid-shaft guides ( p=0.0001,p=0.0001andp=0.001 ) compared to distal guides. The guide extension significantly improved the target registration and translational accuracy in all the volar radius locations ( p=0.001 ). However, in the mid-shaft region, the guide extension yielded an increased total rotational error ( p=0.0001 ).ConclusionOur study demonstrates that positioning accuracy depends on the fitting location and on the guide design. In distal and proximal radial regions, the accuracy of guides with lateral extension is higher than standard guides and is therefore recommended for future use.

Background This study validates the intra-hospital design and 3D printing process of personalized surgical guides to enhance the accuracy of pedicle screw insertion in patients with thoracic scoliotic deformities. It introduces a novel collaborative paradigm between surgeons and engineers, aiming to improve efficiency and reduce errors in the manufacturing of patient-specific instruments (PSIs). Methods The process began with the generation of 3D biomodels of vertebrae from computed tomography scans. Surgical guides were then created using two 3D printing techniques: Fused Filament Fabrication (FFF) with polylactic acid (PLA) and Stereolithography (SLA) with photopolymer resin. Three different prototypes were compared based on multifactorial indicators, including economic cost, macroscopic surface finish, and mechanical stability. The mechanical performance of the guides was evaluated under loads generated during pedicle screw penetration and threading. Results and discussions PLA models printed using FFF were found to be cheaper and simpler to manufacture than SLA resin models. Despite differences observed under a microscope, PLA models exhibited a macroscopic surface f inish comparable to that of SLA resin models. Both materials demonstrated similar mechanical properties, although their values were lower than those reported in the manufacturer’s datasheet. Importantly, both types of guides successfully withstood the mechanical loads generated during surgical procedures. The intra-hospital collaboration between engineers and surgeons was identified as a key factor in improving outcomes and reducing error risks, showcasing the benefits of interdisciplinary teamwork. Conclusions 3D-printed PSIs made from PLA using FFF are more cost-effective and quicker to produce compared to SLA resin models, while achieving similar results in surface finish and mechanical stability. The implementation of a collaborative approach between engineers and surgeons within hospital settings enhances the efficiency and accuracy of patient-specific surgical guide manufacturing, offering a promising solution for improving surgical outcomes in thoracic scoliotic deformities.

Purpose Surgical removal of intra-bony calcific benign lesions is technically challenging regarding its accessibility, proximity to vital structures, and deteriorating effect on the remaining bony structures. Methods Computer-guided buccal cortical plate separation was performed for ten patients using patient-specific osteotomy locating guides and pre-bent plates. The guide was designed to outline the osteotomy, the buccal cortical plate was separated, the lesion was removed, and finally, the pre-bent plates were used to fix the separated cortex. Results Surgical procedures were uneventful for all patients, operation time was 39.5 ± 13.01 min, postoperative pain decreased within the follow-up time intervals, and there was a statistical significant difference between the time intervals ( P value < 0.001). Edema and trismus were acceptable. One case showed nerve affection which resolved after 4 weeks. Conclusion Computer-guided buccal cortical plate separation for removal of intra-bony calcified benign lesions provides a promising approach, especially for inexperienced surgeons. Trial registration ClinicalTrials.gov NCT05329974 . Registered on 6 April 2022—retrospectively registered.

Background: Scaphoid reconstruction after an established non- or malunion is challenging and recent developments have shown the feasibility to reconstruct it with 3D-planned and -printed patient-specific instrumentation. Methods: Our study compared the clinical outcome of computer assisted 3D-reconstructions of the scaphoid using patient-specific guides for primary and revision reconstructions of scaphoid nonunion regarding clinical outcome. Therefore, 39 patients with primary scaphoid nonunion or malunion and 15 patients with nonunion or malunion after a previous operative treatment were treated with patient-specific guides and followed up for a mean of 10.5 months. The consolidation was assessed with a CT-scan, and the time to consolidation was recorded. Pain level, satisfaction, wrist range of motion, and grip strength were measured and compared. Results: The wrist range of motion and grip strength of the two groups were similar, except for the wrist extension, which was significantly reduced in the revision group. Consolidation was observed in 36/39 patients (92%) in the primary group and in 13/15 patients (87%) in the revision group. Our results showed similar clinical results postoperatively between primary reconstructions and revision surgery. Conclusions: The use of 3D-planned and -printed patient-specific instrumentation proves to be similarly effective in revision surgeries for the reconstruction of the scaphoid as it is in primary surgeries.

Additive manufacturing also known as three-dimensional printing (3D printing), provided the ability to produce precise three-dimensional structures, representing a rapidly growing field in Orthopaedics. Its clinical value has been attributed to the ability to create complex three dimensional objects with relative ease and at low cost. However, the available evidence regarding its applications in trauma was heterogeneous. This narrative review aimed to analyze the clinical applications of 3D printing in traumatology. Additionally, the research gaps that emerged in our literature search were underscored. Four application domains were selected based on their prevalence in the screened literature and relative level of clinical implementation within orthopaedic traumatology, including (1) 3D-printed anatomical models, (2) patient-specific surgical guides (PSSGs), (3) 3D-printed implants, and (4) temporary 3D-printed external fixation devices. 3D-printed anatomical models were found to help in reducing operative time, estimated blood loss, and the intraoperative radiation exposure. The use of PSSGs was shown to improve intraoperative accuracy and to provide a basis for consistent, accurate, and reproducible outcomes. However, their implementation was hindered by preparation time, the need for stable anatomical landmarks, and reduced accuracy due to potential soft-tissue injury and swelling. In contrast, 3D-printed implants and external fixation devices constituted promising but less extensively studied applications of 3D printing in trauma. The production of customized implants and external fixators, as suggested by the studies available, was deemed feasible, with comparable mechanical properties and significantly lower cost. Larger multicenter studies are required to support and validate these findings. Overall, based on the available evidence, 3D-printed anatomical models and patient-specific surgical guides demonstrate the highest level of clinical applicability, primarily in preoperative planning and intraoperative guidance.

The purpose of this meta‐analysis was to identify if patient‐specific instrumentation (PSI) could increase the accuracy of the correction in high tibial osteotomy (HTO) and to explore the assessment indices and the necessity of using a PSI in HTO. A systematic search was carried out using online databases. A total of 466 patients were included in 11 papers that matched the inclusion criteria. To evaluate the accuracy of PSI‐assisted HTO, the weight bearing line ratio (WBL%), hip‐knee‐ankle angle (HKA), mechanical medial proximal tibial angle (mMPTA), and posterior tibial slope angle (PTSA) were measured preoperatively and postoperatively and compared to the designed target values. Statistical analysis was performed after strict data extraction with Review Manager (version 5.4). Significant differences were detected in WBL% (MD = −36.41; 95% CI: −42.30 to −30.53; p < 0.00001), HKA (MD = −9.95; 95% CI: –11.65 to –8.25; p < 0.00001), and mMPTA (MD = –8.40; 95% CI:−10.27 to −6.53; p < 0.00001) but not in PTSA (MD = 0.34; 95% CI: −0.59 to 1.27; p = 0.47) between preoperative and postoperative measurements. There was no significant difference between the designed target values and the postoperative correction values of HKA (MD = 0.14; 95% CI: −0.19 to 0.47; p = 0.41) or mMPTA (MD = 0.11; 95% CI −0.34 to 0.55; p = 0.64). The data show that 3D‐based planning of PSI for HTO is both accurate and safe. WBL%, HKA, and mMPTA were the optimal evaluation indicators of coronal plane correction. Sagittal correction is best evaluated by the PTSA. The present study reports that PSI is accurate but not necessary in typical HTO.

Background Sarcomas are associated with a relatively high local recurrence rate of around 30 % in the pelvis. Inadequate surgical margins are the most important reason. However, obtaining adequate margins is particularly difficult in this anatomically demanding region. Recently, three-dimensional (3-D) planning, printed models, and patient-specific instruments (PSI) with cutting blocks have been introduced to improve the precision during surgical tumor resection. This case series illustrates these modern 3-D tools in pelvic tumor surgery. Methods The first consecutive patients with 3-D-planned tumor resection around the pelvis were included in this retrospective study at a University Hospital in 2015. Detailed information about the clinical presentation, imaging techniques, preoperative planning, intraoperative surgical procedures, and postoperative evaluation is provided for each case. The primary outcome was tumor-free resection margins as assessed by a postoperative computed tomography (CT) scan of the specimen. The secondary outcomes were precision of preoperative planning and complications. Results Four patients with pelvic sarcomas were included in this study. The mean follow-up was 7.8 (range, 6.0–9.0) months. The combined use of preoperative planning with 3-D techniques, 3-D-printed models, and PSI for osteotomies led to higher precision (maximal (max) error of 0.4 centimeters (cm)) than conventional 3-D planning and freehand osteotomies (max error of 2.8 cm). Tumor-free margins were obtained where measurable ( n  = 3; margins were not assessable in a patient with curettage). Two insufficiency fractures were noted postoperatively. Conclusions Three-dimensional planning as well as the intraoperative use of 3-D-printed models and PSI are valuable for complex sarcoma resection at the pelvis. Three-dimensionally printed models of the patient anatomy may help visualization and precision. PSI with cutting blocks help perform very precise osteotomies for adequate resection margins.

Purpose For the new generation of mandibular reconstruction, patient-specific mandible reconstruction plates (PSMPs) have been developed which are milled from titanium after preoperative computer planning using CAD/CAM procedures. Resection margins and plate position are determined by surgical guides. In addition, length and shape of the plate and the number and angulation of the screw holes can be planned. Methods 30 patients received such PSMP. Indication ranged from stabilization osteosynthesis, single alloplastic stand-alone reconstruction to microvascular reconstructions. Time for planning, fit of surgical guides and plates, pre-/postoperative occlusion, radiological position of the temporo mandibular joint and complications were recorded.Results The median time for online planning was 35 min. The results concerning fit and handling of the PSMP and the surgical guides were mainly very positive. In six cases, the plan had to be adapted to the intraoperative clinical needs. The postoperative position of the condyles in the temporo mandibular fossae was regular in 28 cases. The evaluation of the occlusion was not representative due to not clearly identifiable occlusion in 2/3 of the cases. Nevertheless, complications like postoperative extraoral plate exposure, infection, graft and flap necrosis or difficulties to position the guides or the plate during surgery occurred.Conclusions Mandibular reconstruction with PSMP offers a broad range of opportunities and benefits compared with standard procedures and can be recommended for all kind of mandibular reconstructions. It is not yet foreseeable whether PSMP will in future become routine clinical practice for mandibular reconstruction or will be confined to selected isolated cases.

Purpose Patients-specific instruments (PSI) for implantation of total knee arthroplasty (TKA) can be used to predict the implant size for both the femur and the tibia component. This study aims to determine the impact of approval of the PSI planning for TKA on the frequency of, and reason for intraoperative changes of implant sizes. Methods The clinical records of 293 patients operated with MRI- (90.4 %) and CT-based (9.6 %) PSI were reviewed for actual used implant size. Preoperative default planning from the technician and approved planning by the operating surgeon were compared with the intraoperative implanted component size for both the femur and tibia. Intraoperative reason for not following the default sizes was outdated. Furthermore, MRI- and CT-based PSI were compared for these outcomes. Results In 93.9 and 91.1 % for, respectively, the femur and tibia (n.s.), the surgeon planned size was implanted during surgery. The predicted size of the femur ( p  < 0.00) and the tibia ( p  < 0.00) component planned by a technician differed from the implanted component sizes in 62 (21.2 %) and 51 (17.4 %) patients, respectively. In 17 cases, the femoral component size was adapted intraoperative based on the expert opinion of the operating surgeon. In 26 cases, the tibia component was changed during the surgery because of a mediolateral overhang, sclerotic bone, medial or lateral release, limited extension and/or fixed varus deformity. The results between the MRI- and CT-based PSI did not differ (n.s.). Conclusions PSI is a tool to help the surgeon to achieve the best possible results during TKA. The planning made by a technician should always be validated and approved by the operating surgeon who has the ultimate responsibility regarding the operation. With PSI, the operating surgeon is able to minimize intraoperative implant size errors in advance to improve operating room efficiency with possible lowering hospital costs per procedure. Levels of evidence III.