Digital Preoperative Planning Research Articles

Accurate Preoperative Digital Planning: The First Mandatory Step to Success in Complex and Unusual Total Hip Arthroplasties: Commentary on an article by Babar Kayani, MBBS, BSc, FRCS(Tr&Orth), PhD, et al.: "The Wagner Cone Stem for Atypical Femoral Anatomy in Total Hip Arthroplasty. A Report of 320 Cases with Minimum 5-Year Follow-up".

Accurate Preoperative Digital Planning: The First Mandatory Step to Success in Complex and Unusual Total Hip Arthroplasties: Commentary on an article by Babar Kayani, MBBS, BSc, FRCS(Tr&Orth), PhD, et al.: "The Wagner Cone Stem for Atypical Femoral Anatomy in Total Hip Arthroplasty. A Report of 320 Cases with Minimum 5-Year Follow-up".

Validation of mediCAD® software for fully digital preoperative planning of total hip arthroplasty: a retrospective study

IntroductionThe planning step that precedes a total hip arthroplasty (THA) procedure is crucial. Digital planning software programs are being increasingly used, although few studies have reported on the reliability of such tools. Furthermore, no studies have been conducted on the mediCAD® software, despite it being widely used in France. This led us to conduct a retrospective study to: (1) assess the accuracy of this planning software, (2) determine the intra- and inter-rater reliability, (3) determine how obesity affects the accuracy of planning. HypothesisTHA planning is accurate and reliable when using the mediCAD® software. Patients and methodsThis was a single center, retrospective study. One hundred one consecutive cases performed by a single experienced surgeon were planned retrospectively by two blinded surgeons on two separate occasions. The acetabular cup was cemented in 90 hips (89%), cementless in 11 hips (11%). A dual mobility cup was used in 21 hips (21%). The femoral stem was cemented in 60 hips (59%). The endpoint was the number of exact plans, defined as the same size as the actual implants. An acceptable match was defined as a difference of one size. The match was unacceptable if the planned and implanted size differed by more than 2 for the acetabular cup or by more than 1 size for the femoral stem. The intra-rater and inter-rater reliability were calculated using the intraclass correlation coefficient (ICC) with 95% confidence intervals (CI). ResultsExact agreement was found by the first rater for 15 planned acetabular cups (15%) and for 45 planned femoral stems (45%) relative to the implants used. The second rater reached exact agreement for 20 planned acetabular cups (20%) and 50 planned femoral stems (50%). The intra-rater reliability for the acetabular cup was average (ICC = 0.57; 95%CI [0.43–0.69]) and poor (ICC = 0.38 95%CI [0.20–054]) for the 1st and 2nd rater, respectively. The intra-rater reliability for the femoral stem was poor for the 1st rater (ICC = 0.47 95%CI [0.30–0.61]) and the 2nd rater (ICC = 0.45 95%CI [0.29–0.60]). The interobserver reliability was low for the planned acetabular cup (ICC = 0.39 95%CI [0.21–0.54]) and the planned femoral stem (ICC = 0.42 95%CI [0.24–0.57]). Overall, when combining the two raters, exact prediction of the acetabular cup was achieved in 31 hips (19%) in non-obese patients and in 7 hips (21%) in obese patients (p = 0.62). DiscussionThis study found acceptable reliability of the mediCAD® software. Experience level, radiograph magnification affected the planning outcome in this study, but obesity did not. We currently do not have the ability to incorporate a reliable radiological scale for two-dimensional templating. Some surgeons prefer using a CT scan, but this costs more than conventional radiographs and exposes the patient to more radiation. This study shows that the mediCAD® software can provide satisfactory output for the preoperative planning of THA. Level of evidenceIII; retrospective, diagnostic, comparative study

Surgeon's Experience and Accuracy of Preoperative Digital Templating in Primary Total Hip Arthroplasty.

Preoperative planning has become essential in performance of total hip arthroplasty (THA). However, data regarding the effect of the planner's experience on the accuracy of digital preoperative planning is limited. The objective of this study was to assess the accuracy of digital templating in THA based on the surgeon's experience. A retrospective study was conducted. An analysis of 98 anteroposterior pelvic radiographs, which were individually templated by four surgeons (two hip surgeons and two orthopaedic residents) using TraumaCad® digital planning, was performed. A comparison of preoperatively planned sizes with implanted sizes was performed to evaluate the accuracy of predicting component size. The results of preoperative planning performed by hip surgeons and orthopaedic residents were compared for testing of the planner's experience. Femoral stem was precisely predicted in 32.4% of cases, acetabular component in 40.3%, and femoral offset in 76.7%. Prediction of cup size showed greater accuracy than femoral size among all observers. No differences in any variable were observed among the four groups (acetabular cup P=0.07, femoral stem P=0.82, femoral offset P=0.06). All measurements showed good reliability (intraclass correlation coefficient [ICC] acetabular cup: 0.76, ICC femoral stem: 0.79). The results of this study might suggest that even though a surgeon's experience supports improved precision during the planning stage, it should not be restricted only to surgeons with a high level of experience. We consider preoperative planning an essential part of the surgery, which should be included in training for orthopaedics residents.

Junior surgeon learning curve for performing digital planning of a first-line uncemented total hip prothesis.

Preoperative digital planning of total hip arthroplasty (THA) anticipates difficulties while increasing implant survival. The objective was to establish the learning curve to produce a reliable and reproducible preoperative planning for THA. We hypothesize that a learning curve exists for planning, and we want to determine the number of procedures required to accomplish it. This prospective study included patients for THA from 02/11/2019 to 01/11/2022. Ten junior (Juniors) and senior surgeons (Seniors) had received dedicated training in the use of the software. Modeling was done blindly by Juniors and Senior before surgery on a standardized front pelvis X-ray (mediCAD 2D Classic Hospital software). Statistical analyses to establish the learning curve were done to compare the Juniors and Seniors. 60% of the Juniors achieved competence after 31.5 ± 12.9 [14-54] planning sessions for the acetabular implant, and 80% after 30.3 ± 8.3 [17-40] planning sessions for the femoral implant. Femoral neck size was achieved by all ten Juniors after 23.1 ± 6.8 [17-38] planning. The offset was correctly restored on the plan by 30% of the Juniors after 33.5 ± 11.6 [18-46] planning. There is a learning curve for 2D planning of uncemented THA. The different planning items seem to have different learning curves. Compared to Seniors, the completion of 75 planning sessions is not sufficient in totality. The competence of the Juniors for the acetabular implant, the length of the neck and the size of the femoral stem are mostly acquired before 75 sessions. Prospective study-Level II.

Robotic-assisted total knee arthroplasty is not associated with improved accuracy in implant position and alignment compared to conventional instrumentation in the execution of a preoperative digital plan.

The primary objective of the present study was to evaluate if robotic-assisted total knee arthroplasty (RO-TKA) results in improved accuracy compared to conventional TKA (CO-TKA) with respect to alignment and component positioning executing a preoperative digital plan. The secondary objective was to compare patient-reported outcome measures (PROMs) between the two groups at 6 months of follow-up (FU). Patients who underwent primary TKA using the concept of constitutional alignment were identified from the database. Each patient underwent preoperative digital planning as well as postoperative evaluation of the preoperative plan (alignment and component position) using mediCAD® software (Hectec GmbH). Two groups were formed: (i) The RO-TKA group (n = 30) consisted of patients who underwent TKA with a robotic surgical system (ROSA®, Zimmer Biomet)and (ii) the CO-TKA group (n = 67) consisted of patients who underwent TKA with conventional instrumentation. To assess accuracy, all qualitative variables were analysed using the χ 2 test. Tegner activity scale, Oxford Knee Score and visual analogue scale were assessed preop and at 6-month FU. To assess differences between the two groups, a 2 × 2 repeated measures analysis of variance was performed. There was no significant (p > 0.05) difference in the accuracy of alignment as well as tibial and femoral component position between the two groups. At the 6-month FU, there was no significant (p > 0.05) difference in PROMs between the two groups. While robotic TKA may have some potential advantages, no significant difference was found between robotic and conventional TKA with respect to limb alignment, clinical outcomes and component positioning. Level III.

PREOPERATIVE PLANNING USING MEDICAD SOFTWARE (GERMANY)

Preoperative planning is an important step in preparing for total hip arthroplasty. Digital preoperative planning allows the surgeon to select templates and overlay them electronically on the image. This way, the necessary measurements of the dimensions of the implants, the position of the implants, and the restoration of the biomechanics are carried out. Digital templating is becoming the preferred method for preoperative planning in total hip arthroplasty (THA). New technologies reduce inconsistencies and errors can be minimized. Our experience with the MediCAD software has shown that its accuracy is within +/- 1 size in 85% of acetabular component placements and 82% of femoral component placements. These results are comparable to those reported in the literature to date.

Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

Analog-digital workflow for complex rehabilitation of severe maxillary atrophy with zygomatic implants: a clinical case

Patients with a complete lack of teeth, severe maxillary atrophy and midface deformity create the most unfavorable conditions for their rehabilitation according to traditional protocols, including bone grafting, sinus lifting and implantation, which forms a complex clinical challenge. Today, zygomatic implants are successfully used as an alternative option for rehabilitation of patients with severe upper jaw atrophy, allowing to reduce the volume of surgical interventions, as well as to shorten the rehabilitation period. Until now, the question of finding an optimal treatment protocol with the use of zygomatic implants remains relevant.
 We proposed an integrated protocol of rehabilitation of patients with severe maxillary atrophy, based on the use of analogue-digital diagnostic tools and treatment outcome planning, as well as including the stages of surgical and prosthetic treatment using the developed technology of zygomatic implant placement and immediate loading with prosthetic jaw prosthesis constructions.
 This work presents a clinical case of the patient (62 years old), whose rehabilitation was performed in accordance with her own protocol: preoperative digital planning according to computer tomography data (Blue Sky Bio Plan., USA), virtual modeling and manufacturing of surgical template for positioning four zygomatic implants (Nobel Biocare, USA), installation of zygomatic implants and immediate fixation of temporary dental prosthesis. Based on the results of follow-up examinations, including X-ray assessment of the zygomatic bones over a period of 6 years no complications were detected.

A deep learning-based automatic segmentation of zygomatic bones from cone-beam computed tomography images: A proof of concept

ObjectivesTo investigate the efficiency and accuracy of a deep learning-based automatic segmentation method for zygomatic bones from cone-beam computed tomography (CBCT) images. MethodsOne hundred thirty CBCT scans were included and randomly divided into three subsets (training, validation, and test) in a 6:2:2 ratio. A deep learning-based model was developed, and it included a classification network and a segmentation network, where an edge supervision module was added to increase the attention of the edges of zygomatic bones. Attention maps were generated by the Grad-CAM and Guided Grad-CAM algorithms to improve the interpretability of the model. The performance of the model was then compared with that of four dentists on 10 CBCT scans from the test dataset. A p value <0.05 was considered statistically significant. ResultsThe accuracy of the classification network was 99.64%. The Dice coefficient (Dice) of the deep learning-based model for the test dataset was 92.34 ± 2.04%, the average surface distance (ASD) was 0.1 ± 0.15 mm, and the 95% Hausdorff distance (HD) was 0.98 ± 0.42 mm. The model required 17.03 s on average to segment zygomatic bones, whereas this task took 49.3 min for dentists to complete. The Dice score of the model for the 10 CBCT scans was 93.2 ± 1.3%, while that of the dentists was 90.37 ± 3.32%. ConclusionsThe proposed deep learning-based model could segment zygomatic bones with high accuracy and efficiency compared with those of dentists. Clinical significanceThe proposed automatic segmentation model for zygomatic bone could generate an accurate 3D model for the preoperative digital planning of zygoma reconstruction, orbital surgery, zygomatic implant surgery, and orthodontics.

Clinical Application of Personalized Digital Surgical Planning and Precise Execution for Severe and Complex Adult Spinal Deformity Correction Utilizing 3D Printing Techniques.

(1) Background: The three-dimensional printing (3DP) technique has been reported to be of great utility in spine surgery. The purpose of this study is to report the clinical application of personalized preoperative digital planning and a 3DP guidance template in the treatment of severe and complex adult spinal deformity. (2) Methods: eight adult patients with severe rigid kyphoscoliosis were given personalized surgical simulation based on the preoperative radiological data. Guidance templates for screw insertion and osteotomy were designed and manufactured according to the planning protocol and used during the correction surgery. The perioperative, and radiological parameters and complications, including surgery duration, estimated blood loss, pre- and post-operative cobb angle, trunk balance, and precision of osteotomy operation with screw implantation were collected retrospectively and analyzed to evaluate the clinical efficacy and safety of this technique. (3) Results: Of the eight patients, the primary pathology of scoliosis included two adult idiopathic scoliosis (ADIS), four congenital scoliosis (CS), one ankylosing spondylitis (AS), and one tuberculosis (TB). Two patients had a previous history of spinal surgery. Three pedicle subtraction osteotomies (PSOs) and five vertebral column resection (VCR) osteotomies were successfully performed with the application of the guide templates. The main cobb angle was corrected from 99.33° to 34.17°, and the kyphosis was corrected from 110.00° to 42.00°. The ratio of osteotomy execution and simulation was 97.02%. In the cohort, the average screw accuracy was 93.04%. (4) Conclusions: The clinical application of personalized digital surgical planning and precise execution via 3D printing guidance templates in the treatment of severe adult rigid deformity is feasible, effective, and easily generalizable. The preoperative osteotomy simulation was executed with high precision, utilizing personalized designed guidance templates. This technique can be used to reduce the surgical risk and difficulty of screw placement and high-level osteotomy.

Application of SolidWorks software in preoperative planning of high tibial osteotomy.

Open-wedge high tibial osteotomy (HTO) is a common surgical treatment for medial osteoarthritis in young and active patients. The accuracy of osteotomy is closely associated with postoperative efficacy. The accuracy of digital preoperative planning is higher than that of the preoperative manual measurement and several computer software with varying accuracy and convenience are used for digital preoperative planning. This study aimed to use the SolidWorks software for HTO preoperative planning and to determine its accuracy and reliability in HTO preoperative planning. We reviewed the data of 28 patients with 54 with medial compartment knee arthritis who underwent open-wedge HTO preoperative planning using SolidWorks between June 2019 and March 2021. The standard anteroposterior standing whole-leg radiographs were assessed before and 6 weeks after the surgery. The correction angle, weight-bearing line (WBL) ratio, mechanical femorotibial angle (mFTA), and medial proximal tibial angle (MPTA) before and after the surgery were compared. The clinical results were evaluated using the Knee Society score. At 6 weeks after the surgery, the WBL ratio was corrected from 16.8% to 50.5%, mFTA was corrected from 6.4° varus to 1.2° valgus, and MPTA was corrected from 83.4° to 89.3°. No significant difference was observed between the predicted correction angle before the surgery and the correction angle measured 6 weeks after the surgery (t = -1.745, p = 0.087). The knee score and function score of Knee Society increased from 76.4 and 80.7 before surgery to 95.0 and 95.7, respectively. The SolidWorks software showed high accuracy and reliability in preoperative planning of open-wedge HTO in patients with medial compartment knee arthritis.

Tentorial Notch Meningiomas: Innovative Preoperative Management and Literature Review.

BackgroundTentorial meningiomas account for only 3–6% of all intracranial meningiomas. Among them, tentorial incisura (notch) location must be considered as a subgroup with specific surgical anatomy and indications, morbidity, and mortality. In this study, we propose an update on preoperative management in order to reduce postoperative deficits.MethodsWe retrospectively collected adult patients treated for incisural meningioma between January 1992 and December 2016 in two different neurosurgical departments. Demographic, clinical, and neuroradiological preoperative and postoperative data were analyzed. In the most recent subgroup of tumors, a preoperative digital simulation was performed to define a volumetric digital quantification of the tumor resection. A review of the pertinent literature has been also done.ResultsWe included 26 patients. The median age was 58.4 years. Onset neurological signs were cranial nerve deficit in 9 patients, hemiparesis in 7, gait disturbance in 3, and intracranial hypertension in 3 patients. Simpson grade I removal was achieved in 12 patients, II in 10, III in 3, and IV in 1 patient. An overall rate of 23% postoperative complications was observed. The average follow-up duration was 68.5 months. Residual tumor was reported in 8 patients. Five patients underwent gamma knife radiosurgery. In 34.6% of patients, the surgical approach was chosen with preoperative digital planning estimating the potential volume of postoperative residual tumor, the target for radiosurgical treatment.ConclusionsA multidisciplinary approach to plan incisural meningiomas management is important. To lower postoperative morbidity and mortality, a careful preoperative case analysis is useful. A planned residual tumor, supported by preoperative simulation imaging, could be safely treated with radiosurgery.

Anatomic Total Shoulder Arthroplasty: Component Size Prediction with 3-Dimensional Pre-Operative Digital Planning.

BackgroundThe rate, complexity, and cost of total shoulder arthroplasty (TSA) continues to grow. Technology has advanced pre-operative templating. Reducing cost of TSA has positive impact for the patient, manufacturer, and hospital. The aim of this study was to evaluate the accuracy of implant size selection based on 3-D templating. Our hypothesis was that pre-operative templating would enable accurate implant prediction within one size.MethodsMulticenter retrospective study of anatomic TSAs templated utilizing 3-D virtual planning technology. This program uses computed tomography (CT) scans allowing the surgeon to predict component sizes of the glenoid and humeral head and stem. Pre-operative templated implant size were compared to actual implant size at the time of surgery. Primary data analysis utilized unweighted Cohen's Kappa test.Results111 TSAs were analyzed from five surgeons. Pre-operative templated glenoid sizes were within one size of actual implant in 99% and exactly matched in 89%. For patients requiring a posterior glenoid augment (n = 14), 100% of implants were within one size of the template and 93% matched exactly. For stemless humeral components (n = 87) implanted, 98% matched the pre-operative template within one size with 79% exactly matched. For stemmed components (n = 24), 88% of cases were within one size of the preoperative plan and exactly matching in 83%. Humeral head diameter matched within one size of the pre-operative template in 84% of cases and exactly matched in 72%.ConclusionPre-operative 3-D templating for TSAs can accurately predict glenoid and humeral component size. This study sets the groundwork for utilization of pre-operative 3-D templating as a potential method to reduce overall TSA costs by managing cost of implants, reducing inventory needs, and improving surgical efficiency.

Computer-assisted implant placement and full-arch immediate loading with digitally prefabricated provisional prostheses without cast: a prospective pilot cohort study

BackgroundImmediate loading of implant-supported full-arch rehabilitations has become routine practice when treating edentulous patients. The combination of static computer-aided implant surgery (s-CAIS) and digital prosthetic workflow could eliminate several treatment steps and facilitate prostheses delivery.The aim of this study is to evaluate the 1-year results of digitally prefabricated polymethyl methacrylate (PMMA) provisional prostheses without a cast for full-arch computer-assisted immediate loading.Materials and methodsA digital pre-operative treatment planning was realized for all patients: dental implants and screw-retained abutments were selected in the planning software and two surgical templates were fabricated for each patient. The first template was mucosa or teeth-supported to drill the holes for fixating pins, while the second template was placed after raising a full-thickness flap and was supported by pins as well as soft or hard tissue distal support. Furthermore, based on the surgical planning, interim prostheses were digitally designed and milled of PMMA resin blocks with subsequent pink resin veneering. Osteotomies and implant placement were performed through the surgical guides and all implants were immediately loaded with prefabricated full-arch interim prostheses directly connected to titanium copings with a flowable resin.ResultsA total of 55 dental implants were placed in ten patients. In all cases, interim prostheses allowed the insertion of titanium copings without the need of access hole enlargement or adaptation. All the prostheses had 1 year of functional loading to simulate the long provisional phase. No screw loosening occurred at the first removal of the prostheses after implant osseointegration. No fracture occurred during the whole period. After 1 year, the mean marginal bone loss level was 0.37 ± 0.06 mm, while the implant survival rate was 98.18% (n=54/55), with just one implant failing but not affecting final prosthesis delivery to the patient.ConclusionsWithin the limitations of the present study, the authors concluded that digitally prefabricated provisional prostheses for full-arch immediate loading with s-CAIS could be a valid alternative treatment modality. Milled PMMA restorations proved to be durable enough during the long provisional phase, without prosthetic complications.

Forehead Flap Templates for Nasal Reconstruction Digitally Developed From 2D and 3D Images.

The forehead flap is the gold standard procedure for nasal reconstruction to address a partial or complete rhinectomy. Traditionally, the three-dimensional (3D) nasal defect is manually templated intraoperatively to design the two-dimensional (2D) flap shape on intact morphology. In this clinical study, digital preoperative planning is used to template with computer-assisted design and manufacturing. Preoperative digital templates were implemented for 3 representative patients (1 in Supplementary Digital Content, http://links.lww.com/SCS/D60). This includes designs for a hemi-rhinectomy case from 3D mirroring, a partial total rhinectomy case generated from a 3D scan, and a total rhinectomy case generated from a 3D morphable model based on a prepathology 2D photo. Digital unwrapping flattened the patient's 3D nasal geometry designs to 2D skin flap shapes. Finally, the 2D designs were printed as traceable intraoperative templates at a 1:1 scale. This clinical study demonstrates the application of digital 3D preoperative templating to improve workflow for nasal reconstruction.

Особенности предоперационного планирования эндопротезирования тазобедренного сустава

Relevance. Preoperative planning is an integral stage of hip replacement surgery, which reduces the number of complications and improves the accuracy of the installation of endoprosthesis components. Goal. Assess the accuracy of digital preoperative planning using mediCAD® v.6. Material and methods. The study included data from 276 patients with idiopathic coxarthrosis who were treated at the orthopedic department of the Center of Traumatology and Orthopedics of the Main Military Clinical Hospital named after N.N. Burdenko in the period from 2018 to 2020.The patients had X-rays of the pelvis and hip joint in two projections. All patients underwent total hip arthroplasty with cementless endoprostheses. Before surgery, all patients underwent preoperative planning using the mediCAD® v.6 software. After the operation, a control X-ray was performed, followed by an assessment of the obtained images in the same software. The planning accuracy was evaluated by comparing the parameters that were calculated in the program before the operation with the parameters of the installed implants. The results. The conducted study demonstrated the high accuracy of digital preoperative planning. The coincidence of the planned sizes of the acetabular component of the endoprosthesis and a deviation within +/- one size was observed in 93% of patients, femoral — in 84% of patients. Conclusion. Preoperative planning is an integral stage of hip replacement surgery, which allows you to perform the necessary preparation for the intervention. Digital planning allows you to simplify and speed up the process of preparing for an operation and improve the quality of its execution.

Computer‐guided core needle biopsy of the jaws: A technical report

AbstractObjectiveThe aim of the present work is to communicate the use of cone beam‐computed tomography (CBCT) and digital surgery planning software for the fabrication of high‐precision surgical guides to perform core needle biopsy of intraosseous lesions in the jaws.MethodsDigital preoperative surgical planning software originally designed for dental implant surgery and CBCT images were used to fabricate a patient‐specific stereolithographic surgical guide to perform a core needle biopsy of a mixed osteolytic lesion in the mandible in a 20‐year‐old patient. The core needle biopsy was performed in an outpatient setting under local anaesthesia.ResultsThe surgical guide for core needle biopsy fabricated using CBCT images and dental implant software allowed obtaining a tissue sample of an intraosseous lesion, while providing control of the positioning, angulation, and depth of the needle, and minimizing the risk of damaging neighboring structures.ConclusionsCBCT and digital preoperative surgical planning software are useful to fabricate high precision surgical guides to perform core needle biopsy, and they allow correcting errors and solving problems that may arise during the surgery. It is necessary to perform the procedure on a cohort of patients in order to validate the method.

Effects of surgeon experience and patient characteristics on accuracy of digital pre-operative planning in total hip arthroplasty.

The effect of surgeon experience on accuracy of digital pre-operative planning for total hip arthroplasty (THA) remains unclear. The aims of our study were to compare pre-operative planning accuracy between fellow-trained orthopaedic surgeons and residents and to explore whether surgery indication effects the prediction accuracy. We prospectively reviewed 101 patients who underwent pre-operative digital templating for THA in our center from January 2019 to January 2020 with King Mark device. Extracted data included baseline characteristics and indication for primary arthroplasty. Pre-operative digital templating was performed separately by both a fellow-trained surgeon and a resident. Accuracy of each group was compared with the implanted components. The overall adequate pre-operative planning of the acetabular cup (exact or +/-1 size match) by the fellow-trained group was higher compared with the resident's group (77.2 and 64.3% respectively, p = 0.037), whereas the overall adequate pre-operative planning of the femoral stem (exact or +/-1 size match) was higher in the resident's group compared with the fellow-trained group (83.2 and 61.4% respectively, p < =0.001). The fellow-trained group showed better pre-operative planning of complex cases (developmental dysplasia of the hip and avascular necrosis of femoral head) than the resident's group. The experience of the planner does not significantly affect the accuracy of correctly predicting component sizes. However, in complex cases, fellow-trained surgeons should assist residents in digital pre-operative templating for THA.

Development of three-dimensional preoperative planning system for the osteosynthesis of distal humerus fractures

BackgroundTo reproduce anatomical reduction and appropriate implant placement/choices during osteosynthesis for elbow fractures, we developed a 3D preoperative planning system. To assess the utility of 3D digital preoperative planning for the osteosynthesis of distal humerus fractures, we evaluated the reproducibility of implant reduction shapes and placements in patients with distal humerus fractures.MethodsTwelve patients with distal humerus fractures who underwent osteosynthesis using 3D preoperative planning were evaluated. Reduction shapes were evaluated by the angle between the diaphysis axis and a line connecting the vertices of the medial epicondyle and the lateral epicondyle (epicondyle angle), and the angle between the diaphysis axis and the articular surface (joint angle) in the coronal plane, and the distance between the anterior diaphysis and the anterior articular surface in the sagittal plane (anterior distance) based on 3D images of the distal humerus. In addition, the implant positions were evaluated by the positions of the proximal and posterior edge of the plate, and the angle of the plate to the epicondyle line. The reproducibility was evaluated by intra-class correlation coefficients of the parameters between pre- and postoperative images.ResultsThe intra-class correlation coefficients were 0.545, 0.802, and 0.372 for the epicondyle angle, joint angle, and anterior distance, respectively. The differences in the measurements between the preoperative plan and postoperative reduction were 2.1 ± 2.1 degrees, 2.3 ± 1.8 degrees, and 2.8 ± 2.0 mm, for the epicondyle angle, joint angle, and anterior distance, respectively. The intra-class correlation coefficients were 0.983, 0.661, and 0.653 for the proximal and posterior plate positions, and the angle to the epicondyle, respectively. The differences in the measurements between the preoperative plan and postoperative reduction were 3.3 ± 2.1 mm, 2.7 ± 1.7 mm and 9.7 ± 9.8 degrees, for the plate positions of proximal and posterior edge, and the angle of the plate to the epicondyle line, respectively. There were significant correlations for the epicondyle angle, joint angle, and plate positions.Conclusions3D preoperative planning for osteosynthesis of distal humerus fracture was reproducible for the reduction shape of the coronal view and the plate positions. It may be helpful for acquiring practical images of osteosynthesis in distal humerus fractures.Level of evidenceLevel III, a case–control study.

Accuracy of Computer-Aided Design/Computer-Aided Manufacturing Surgical Template for Guidance of Dental Implant Distraction in Mandibular Reconstruction With Free Fibula Flaps.

The direction and orientation of the osteotomized upper segments in dental implant distractor (DID) can be compromised due to an unpredicted vector of distraction. The present study aimed to evaluate the accuracy of computer-aided design/computer-aided manufacturing (CAD/CAM) surgical templates to precisely guide the distraction process in lengthening of the alveolar height for functional mandibular reconstruction. This retrospective study included all consecutive patients who underwent digitally designed mandibular reconstruction using the fibular flap and DID with the help of CAD/CAM designed surgical templates in a single-stage procedure from 2011 to 2014. First, the preoperative digital planning was performed on 3-dimensional models. Afterward, simulation of the distraction process was made on the virtual model and the resulting new height of the fibula was evaluated. The preoperative simulation was applied to accurately define the exact location and path of the DID device to achieve the suitable vertical height. The preoperative digital planning was used to help the design of the CAD/CAM surgical template, which was then fabricated by means of the 3-dimensional printing technology. The manufactured surgical template-assisted both horizontal and vertical osteotomies of the fibular segments and defining the DID path to lead the distractor into the accurate position. The outcome evaluation was achieved through comparing both preoperative virtual planning with postoperative actual outcomes. This study included 14 subjects, 8 were males and 6 were females. The mean age at time of surgery was 31.07 years (range 18-47). All fibular flaps showed 100% success rate. The mean vertical bone height attained with the DID device was 11.35 mm. The vertical and horizontal osteotomies of the fibular segments were completed, then the DID devices were successfully positioned guided by the template. The mean values of the linear and angular deviations for the distractor position and upper segments were calculated and recorded. The maximum linear deviation between the virtual and the postoperative actual distractors was 0.93 mm in the anteroposterior direction, and the greatest in the horizontal plane was 4.64°. CAD/CAM surgical templates can accurately guide the direction and orientation of the DID device for functional mandibular reconstruction; therefore, helping to improve the outcomes by accurately transferring the preoperative virtual plan to real surgical procedure.