Accurate Osteotomy Research Articles

Expert Consensus for the Treatment Algorithm for Navigationassisted Reconstruction of Maxillofacial Deformities.

Deformities of the maxillofacial region following trauma and ablative surgery are devastating and not uncommon. Reconstruction of such defects is a surgically challenging procedure. Conventionally, reconstruction of dental arch defects lacks preoperative customised planning and relies heavily on the surgeon experience to ensure optimum surgical outcomes. The restoration of the dental arch shape and function has taken precedence after an extensive tumour resection surgery, especially in the current age of technological advancement. Thus, personalised and accurate reconstruction of dental arch defects has become a new goal. Computer-assisted surgery, especially navigation-assisted surgery, has gained popularity of late, in reconstructing deformities and restoring facial symmetry, appearance and function in the maxillofacial region. This technology provides a clearer three-dimensional visualisation of the area of interest and its relationship with the adjacent vital structures. Together with preoperative virtual surgical planning, it allows more specific and accurate osteotomies, thus reducing the ischemia and total operating times substantially. The risk of complications is also minimised whilst improving the final surgical outcomes. The use of the intraoperative navigation system and other computer-assisted surgical techniques during surgery can significantly improve the precision of the reconstruction of dental arch deformities, and achieve personalised and functional reconstructive goals while enhancing the quality of life of patients postoperatively. The Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association provides the present professional perspective and treatment protocol for navigation-guided reconstruction of dental arch defects, to allow standardisation of the technique while promoting its application among oral and maxillofacial surgeons.

Guidelines for the Use of Resection Guides for Subperiosteal Maxillary Implants in Cases of Terminal Dentition - A Novel Approach.

Introduction:We described our rationale and experiences with the use of cutting jigs for vertical ostectomy in cases of terminal maxillary dentition when edentulation and an additively manufactured subperiosteal jaw implant (AMSJI®) are planned.Material and Methods:Our experience covers 15 patients treated by four clinicians. We tabulated our criteria for planning and manufacturing vertical and horizontal ostectomy guides.Results:In order to guarantee accurate osteotomy, titanium guides are preferable to guides made of polymer. The most important consideration is to avoid acute angles in the buccal arms of the AMSJI®. It is up to the surgeon whether to screw-fix the ostectomy guides or to use handles to maintain their position.Discussion:Guided ostectomy has the potential to extend the use of AMSJI® to cases where teeth have yet to be removed or where the contours of the residual bone are not favorable. The use of guided ostectomy in such cases lessens the time between edentulation and implantation and improves the design of the implants.

3D-printed pelvis model is an efficient method of osteotomy simulation for the treatment of developmental dysplasia of the hip.

Developmental dysplasia of the hip (DDH) is a congenital or developmental deformation of the hip joint, which may require a high number of surgical interventions. It has been indicated that 3D printing may be used to simulate a fractured pelvis to facilitate the fixation of plates during the surgical procedure. In the present double-blinded randomized clinical trial, the utility of the 3D-printed pelvis model, comprising 3D reconstruction, reverse engineering and rapid prototyping, in the treatment of DDH was evaluated with 3D CT as control. The value of the 3D-printed pelvis model in the surgical management and development of a strategy for an individualized operation for DDH using osteotomy simulation was also assessed. The results indicated that use of the 3D-printed pelvis model increased the success rate of the operation with a shortened surgery time and post-operative recovery time for DDH patients. In addition, the application of the 3D-printed pelvis model allowed for more efficient surgical management of DDH than 3D CT and promoted post-operative recovery of the DDH patients. Pre-operative planning using the 3D-printed pelvis model was feasible for DDH patients. Furthermore, few patients exhibited delayed incision healing, wound infection or nonunion in the DDH group with osteotomy simulation using the 3D-printed pelvis model or 3D-CT. In conclusion, the present study indicated that the 3D-printed pelvis model, including 3D reconstruction, reverse engineering and rapid prototyping, constitutes an efficient tool for pelvic osteotomy simulation, which improves personalized pre-operative planning by providing a visual and accurate osteotomy model for patients with DDH (Chinese Trial Registry No. KCT0012374).

Guidelines for the Execution of True Spherical Osteotomies Using a Modified Dome Blade Design.

The purpose of this study was to explore the trigonometric principles of the spherical osteotomy, establish guidelines for its application and test the guidelines on bone models using a new blade design. We propose a new rule of osteotomies incorporating the outlined geometric principles, and applicable to the use of spherical cuts in veterinary orthopaedic surgery. The trigonometric principles for the execution of neutral, closing and opening spherical osteotomies were explored in silico. A modification of the existing commercially available dome blade was designed and manufactured such that it facilitated the performance of spherical osteotomy with a minimized blade radius. A pilot study was performed whereby the modified dome blade was used to create spherical osteotomy in canine radial bone models. The surfaces of the osteotomy models were laser-scanned using a three-dimensional (3D) scanner; the resultant scans were imported into and analysed using a commercial 3D analysis software. The accuracy of osteotomy execution was measured as the distance between the targeted centre of osteotomy and the actual centre of osteotomy as found on the 3D scans. By utilizing the geometric principles of spherical osteotomy, an accurate osteotomy position was achieved. The centre of the spherical cut performed on bone models was confirmed to be within 5% tolerance of the location as planned in silico demonstrating the accurate and relevant clinical application of geometric principles. The trigonometric guidelines for the execution of spherical osteotomy can be applied in a pre-clinical environment with accuracy. The new guidelines combined with the proposed new rule for spherical osteotomy utilizing the new blade design are translatable into clinical application, permitting the surgeon to accurately plan osteotomy application while mitigating the significant loss of bone-to-bone contact during correction of torsional deformities inherent in the principles of dome osteotomy use.

Efficacy evaluation of three-dimensional printing assisted osteotomy guide plate in accurate osteotomy of adolescent cubitus varus deformity

BackgroundThis present study is aimed to retrospectively assess the efficacy of three-dimensional (3D) printing assisted osteotomy guide plate in accurate osteotomy of adolescent cubitus varus deformity.Material and methodsTwenty-five patients (15 males and 10 females) with the cubitus varus deformity from June 2014 to December 2017 were included in this study and were enrolled into the conventional group (n = 11) and 3D printing group (n = 14) according to the different surgical approaches. The operation time, intraoperative blood loss, osteotomy degrees, osteotomy end union time, and postoperative complications between the two groups were observed and recorded.ResultsCompared with the conventional group, the 3D printing group has the advantages of shorter operation time, less intraoperative blood loss, higher rate of excellent correction, and higher rate of the parents’ excellent satisfaction with appearance after deformity correction (P < 0.001, P < 0.001, P = 0.019, P = 0.023). Nevertheless, no significant difference was presented in postoperative carrying angle of the deformed side and total complication rate between the two groups (P = 0.626, P = 0.371).ConclusionsThe operation assisted by 3D printing osteotomy guide plate to correct the adolescent cubitus varus deformity is feasible and effective, which might be an optional approach to promote the accurate osteotomy and optimize the efficacy.

Expert consensus on techniques of navigation-guided reconstruction of jaw defect

Deformities of the maxillofacial region following trauma and ablative surgery are devastating and not uncommon. Reconstruction of such defects is a surgically challenging procedure. Conventionally, reconstruction of the jaw defects lacks pre-operative customized planning and relies heavily on surgeons' experiences to ensure optimum surgical outcomes. The restoration of jaw shape and function has taken precedence after an extensive tumor resection surgery, especially in the current age of technological advancement. Thus, personalized and accurate reconstruction of jaw defects has become a new goal. Computer-assisted surgery especially navigation-assisted surgery has gained popularity of late, in reconstructing deformities and restoring facial symmetry, appearance and function in the maxillofacial region. This technology provides a clearer three-dimensional visualization of the area of interest and its relationship with the adjacent vital structures. With pre-operative virtual surgical planning, it allows more specific and accurate osteotomies, thus reducing the ischemia and total operating times substantially. The risk of complications is also minimized whilst improving the final surgical outcomes. The use of intra-operative navigation system and other computer-assisted surgical techniques in the surgery can significantly improve the precision of the reconstruction of jaw deformities and achieve personalized and functional reconstructive goals while enhancing the patients' quality of life post-operatively. The Society of Oral and Maxillofacial Surgery, Chinese Stomatological Association provides this professional perspective and present treatment protocol for navigation-guided reconstruction of jaw defect to allow standardization of the techniques while promoting its application among the oral and maxillofacial surgeons.

Design of a Three-Dimensional-Printed Surgical Glove for Minimal-Incision Podiatric Surgery.

Precision in minimal-incision surgery allows surgeons to achieve accurate osteotomies and patients to avoid risks. Herein, a surgical guide for the foot is designed and validated in vitro using resin foot models for hallux abducto valgus surgery. Three individuals with different experience levels (an undergraduate student, a master's student, and an experienced podiatric physician) performed an Akin osteotomy, a Reverdin osteotomy, and a basal osteotomy of the first metatarsal. The average measurements of each osteotomy and the angle of the basal osteotomy do not reveal significant differences among the three surgeons. A shorter deviation from the planned measurements has been observed in variables corresponding to the Akin osteotomy (the maximum deviation in the measurement of the distance from the proximal medial end of the Akin osteotomy to the first metatarsophalangeal joint interline was 1.67 mm, and the maximum deviation from the proximal lateral end of the Akin osteotomy to the first metatarsophalangeal joint interline was 1.00 mm). As for the Reverdin osteotomies, the maximum deviations in the measurement of the distance from the proximal medial end of the osteotomy to the first metatarsophalangeal joint interline were 3.60 and 3.53 mm in the expert and undergraduate surgeons, respectively. All of the osteotomies were precise among the groups, reducing the learning curve to the maximum. The three-dimensional-printed prototype has been proven effective in guiding surgeons to perform different types of osteotomies. Minimal deviations from the predefined osteotomies were found among the three surgeons.

Using 3D models in orthopedic oncology: presenting personalized advantages in surgical planning and intraoperative outcomes

BackgroundThree Dimensional (3D) printed models can aid in effective pre-operative planning by defining the geometry of tumor mass, bone loss, and nearby vessels to help determine the most accurate osteotomy site and the most appropriate prosthesis, especially in the case of complex acetabular deficiency, resulting in decreased operative time and decreased blood loss.MethodsFour complicated cases were selected, reconstructed and printed. These 4 cases were divided in 3 groups of 3D printed models. Group 1 consisted of anatomical models with major vascular considerations during surgery. Group 2 consisted of an anatomical model showing a bone defect, which was intended to be used for substantial instrumentation, pre-operatively. Group 3 consisted of an extra-compartmental bone tumor which displayed a deteriorated cortical outline; thus, using CT and MRI fused images to reconstruct the model accurately. An orthopedic surgeon created the 3D models of groups 1 and 2 using standard segmentation techniques. Because group 3 required complex techniques, an engineer assisted during digital model construction.ResultsThese models helped to guide the orthopedic surgeon in creating a personalized pre-operative plan and a physical simulation. The models proved to be beneficial and assisted with all 4 cases, by decreasing blood loss, operative time and surgical incision length, and helped to select the appropriate acetabular supporting ring in complex acetabular deficiency, pre-operatively.ConclusionQualitatively, using 3D printing in tumor cases, provides personalized advantages regarding the various characteristics of each skeletal tumor.

Computer-aided modification of Reverdin osteotomy template for hallux valgus

Objective To provide a method to modify accurately the Reverdin osteotomy template for hallux valgus using 3D reconstruction and printing. Methods From June 2015 to June 2016, 11 patients (16 feet) with hallux valgus at our departments underwent weight-bearing X-ray examination and continuous spiral CT scanning of the feet. The outer turning angle of hallux averaged 33.50°±6.80°, the first intermetatarsal angle 12.20°±2.90° and the distal metatarsal articular angle 15.20°±2.60°. Their imaging Dicom data were imported into Materialise Mimics Innovation Suite v16.0 software for generation of 3D models of the pelvis which were then stored in stereolithography format and imported into Imageware 12 software. After optimal templates were reversely rebuilt to have the best angles and range for Reverdin osteotomy in the 3D models, they were manufactured by a rapid prototyping machine. The osteotomy templates were used in surgery to guide the osteotomy of hallux valgus. Correction of hallux valgus, bone union at the osteotomy sites and weight-bearing walk were observed postoperatively. Results Accurate angles of osteotomy were confirmed by postoperative radiography in all the 16 feet. Follow-ups for 6 to 12 months showed in the 16 feet a mean outer turning angle of hallux of 7.31°±0.33° (from 5° to 11°) and a mean correction of 21.92°±4.8° (from 13° to 24°). Bone union was fine at the osteotomy sites and no pain was reported during weight-bearing walk. Conclusion 3D reconstruction and printing can produce a patient-specific template for accurate Reverdin osteotomy for hallux valgus, leading to increased contact area and fine union of the osteotomy ends. Key words: Imaging, three-dimensional; Rapid prototyping; Clubfoot; Anatomy

Evaluation of Accuracy of a Three-Dimensional Printed Model in Open-Wedge High Tibial Osteotomy.

The purpose of this study was to evaluate the usefulness of a three-dimensional (3D) printed model for open-wedge high tibial osteotomy (HTO). This study retrospectively evaluated 20 patients with medial knee osteoarthritis and varus deformity. Between October 2015 and July 2016, the patients underwent open-wedge HTO using a 3D printed model. The mean age of patients was 55.2 years (range, 51-60 years). The mean preoperative mechanical femorotibial angle (mFTA) was varus 7.8 degrees (range, varus 4.7-11.6 degrees). After measuring the target angle using full-length lower limb weight-bearing radiography, the osteotomy was simulated using 3D images obtained from computed tomography (CT) with the 3D Slicer program. On the basis of the simulated osteotomy section and the target angle, the model was then designed and printed. Open-wedge HTO was then performed by applying the 3D printed model to the opening gap. The accuracy of osteotomy and the change in posterior tibial slope (PTS) angle were evaluated. The weight-bearing line on the tibial plateau was corrected from a preoperative mean of 19.5 ± 9.8% to a postoperative mean of 63.1 ± 6.1% (p < 0.001). The postoperative values were not statistically significantly different from the preoperative target points (p = 0.688). The mFTA was corrected to a postoperative mean of valgus 3.8 ± 1.4 degrees. The PTS angle showed no significant change (p = 0.256). A 3D printed model using CT may be useful for preoperative planning of open-wedge HTO. Satisfactory correction can be obtained without a change in the PTS.

The Design of Deformed Femur Osteotomy System

In order to achieve more accurate deformity femoral osteotomy, a software system for deformity femoral osteotomy was designed to facilitate the clinical preoperative simulation. First, 3D modeling was simulated using Mimics17.0 and saved as STL file. Then, MFC and OpenGL was utilized to build the deformed femur osteotomy system, the accurate osteotome position and osteotomy angle were obtained by fitting the axis of the deformed femoral shaft and the geometric center of the greater trochanter of femoral head. Finally, mock splicing was performed to determine the postoperative neck angle. A case of abnormal femoral STL model was introduced into the osteotomy system and whose collodiaphyseal angle was measured as 57.7 °, input osteotomy angle was 60 °, and the postoperative collodiaphyseal angle was measured to be 102.3 ° after completing the osteotomy simulation. The experimental results show that the system can quickly provide doctors with a more accurate osteotomy program, as well as preoperative surgical simulation, which will save the doctor's clinical diagnosis time and increase the accuracy of osteotomy.

Accuracy of Virtual Surgical Planning in Treatment of Temporomandibular Joint Ankylosis Using Distraction Osteogenesis: Comparison of Planned and Actual Results

This study evaluated the accuracy of virtual surgical planning and 3-dimensional (3D) printed templates to guide osteotomy and distraction osteogenesis (DO) in the treatment of temporomandibular joint (TMJ) ankylosis and secondary mandibular deformity. Seven consecutive patients diagnosed with TMJ ankylosis and mandibular deformities were included. A composite skull model was obtained with data from spiral computed tomography (CT) and laser scanning of the dental arch. A virtual surgical simulation was performed using Dolphin Imaging 11.7 Premium (Dolphin Imaging and Management Solutions, Chatsworth, CA). Then, the virtual plan was transferred to the operation using 2 surgical templates. These templates were designed by 3D printing using data from the virtual surgical simulation for guiding the osteotomy and the DO, respectively. The preoperative measurement and differences between the actual mandibular position and the virtual plan were analyzed. Postoperative radiographs, CT images, and quantitative analysis showed a clinically acceptable precision for the position of the mandible. The mean length of the mandible and the vertical height of the DO were 79.1 and 14.9mm, respectively. With the 3D superimposition and linear measurement, the mean difference between the virtual plan and the actual results ranged from 0.64±0.20 to 1.90±0.85mm. Allpatients obtained satisfactory changes in the facial profile and marked improvement in postoperative pharyngeal airway space and mouth opening. The results of this study showed that virtual surgical planning and 3D printed guiding templates facilitated treatment planning, an accurate osteotomy, repositioning of bony segments, and contouring of the mandibular border in the treatment of TMJ ankylosis and secondary mandibular deformity.

Surgical treatment for shepherd's crook deformity in fibrous dysplasia: THERE IS NO BEST, ONLY BETTER.

The optimal strategy for shepherd's crook deformity correction remains technically challenging. In particular, it is difficult to performan accurate osteotomy based on the pre-operative correction plan. Moreover, the choice of ideal hardware remains unclear. In addition, when combined with the deformity of knee joint, the sequence of deformity correction is another overlooked factor when making a correction strategy. From February 2012 to March 2014, we retrospectively examined a cases series in our department involving the creation of three-dimensional (3D) printing osteotomy templates and inner fixation for shepherd's crook deformity in fibrous dysplasia. A total of ten patients of shepherd's crook deformity were enrolled in this study. The neck shaft angle was corrected from a mean value of 88.1° (range, 73-105°) pre-operatively to a mean value of 128.5° (range, 120-135°) post-operatively; no marked loss in the value was observed (mean, 123.7°; range, 115-130°) at the final follow-up. In addition, compared with patients using dynamic hip screw (DHS), longer operation time and additional blood loss were recorded in patients using intramedullary nail (IN). Moreover, after correction of shepherd's crook deformity, two patients were observed more predominant on their pre-existing valgus knee deformity. 3D printing osteotomy templates facilitate the correction of shepherd's crook deformity. Dynamic hip screw (DHS), combined with polymethylmethacrylate (PMMA) augmentation, yields excellent outcomes and ensures easy placement and non-intramedullary manipulation, lower bleeding volume, and reduced operation time. Prior to the correction of shepherd's crook deformity, the mechanical axis of the lower limb should be carefully examined, and any evidence of valgus knee deformity should be addressed in advance.

Intraoperative O-arm-navigated resection in musculoskeletal tumors

BackgroundAlthough emerging evidence has suggested that computer-assisted navigation allows surgeons to plan the optimal level of resection without compromising the surgical margins, the precise accuracy of the procedures has been unclear. The aim of this study was to investigate the accuracy and safety of the musculoskeletal tumor resection using O-arm/Stealth intraoperative navigation assistance. MethodsA retrospective study of six patients with bone and soft tissue tumors who underwent surgical resection using O-arm/Stealth navigation system was performed. The histological diagnosis was osteosarcoma, metastatic bone tumor, leiomyosarcoma, undifferentiated sarcoma, and synovial sarcoma, respectively. Tumor resection was performed according to planned osteotomy planes determined on O-arm/Stealth three-dimensional intraoperative images. The resection accuracy, length of time for the procedures, surgical margins, and perioperative complications were evaluated. ResultsThe distances between the entry and exit points for the planned and actual cuts were 1.5 ± 0.3 mm and 2.3 ± 0.3 mm, respectively, and the mean discrepancy of the osteotomy angle was 2.8 ± 1.2°. The mean length of time required for navigation was 14 min. A histological examination revealed clear margins in all patients. There were no complications related to navigation, and no patients developed local recurrence during a mean follow-up of 30.6 months. ConclusionsThe O-arm/Stealth intraoperative CT navigation system provides safe and accurate osteotomy in musculoskeletal tumor resections. However, surgeons should keep in mind and be careful of minimal errors during osteotomy, which are around 2 mm from the planned line.

Augmented Reality Guided Osteotomy in Hallux Valgus Surgery

Category: Bunion Introduction/Purpose: An optimal osteotomy angle can avoid shortening of the first metatarsal bone after hallux valgus surgery and therefore reduce the risk of transfer-metatarsalgia. Up to date the osteotomy is performed free-hand without guidance and is therefore prone to unwanted variability in accuracy. The purpose of the present ex-vivo study was to investigate whether overlaying a hologram (augmented reality, AR) would improve accuracy of the distal osteotomy during hallux valgus surgery. Methods: A polyamide foot skeleton was constructed based a CT scan of a cadaveric foot and covered with medical silicon soft tissue. Three different polyamide first metatarsals were inserted to simulate a light, moderate and severe hallux valgus deformity. Distal Osteotomies of the first metatarsals were performed by two surgeons with different levels of surgical experience each with (AR, n=15x2) or without (controls, n=15x2) overlay of a hologram depicting an angle of osteotomy perpendicular to the second metatarsal in the transverse plane. Subsequently, the deviation to the plumb line of the second metatarsal in the transverse plane of all 60 osteotomies angles were optically measured and statistically analyzed. Results: Overall, the AR-guided osteotomies were more accurate (4.9 ± 4.2°) compared to the freehand cuts (6.7± 6.1°) by tendency (p=0.2). However, while the inexperienced surgeon performed more accurate osteotomies with AR with a mean angle of 6.4± 3.5° compared to freehand 10.5 ± 5.5° (p=0.02), no significant difference was noticed for the experienced surgeon with an osteotomy angle of around 3° in both cases. Conclusion: This pilot-study suggests that augmented reality guided osteotomies can potentially improve accuracy during hallux valgus surgery, particularly for less experienced surgeons. However, clinical studies are needed to investigate the clinical benefit of augmented reality in hallux valgus surgery.

Clinical significance of three-dimensional skeleton-arterial model in the management of delayed reconstruction of acetabular fractures

BackgroundDelayed reconstruction of acetabular fractures remains a challenging task for orthopedists because of malunion, fracture line absorption, and scar formation. Accurate osteotomy, interfragmentary release, and proper adaptation of plates are keys to successful surgery. Prevention of superior gluteal artery (SGA) injury induced by cleaning of the osteotylus and reduction of the sciatic notch is also important. Therefore, sufficient preoperative planning is essential. However, traditional planning methods do not readily provide direct visual and tactile feedback to surgeons. Rapid prototyping (RP) models have provided new opportunities in the preoperative planning of delayed reconstruction of acetabular fractures. We hypothesized that a three-dimensional (3D) skeleton-arterial model would improve both preoperative planning in the management of fractures and arteries and intraoperative assistance during delayed reconstruction of complex acetabular fractures.MethodsEight patients were enrolled in this study. Data on the skeleton and arteries were obtained from computed tomography and angiography scans and used to produce RP models. Preoperative surgical planning and intraoperative assistance were performed using these models as references.ResultsAll 3D skeleton-arterial models were extremely accurate. Reduction and fixation were performed programmatically and smoothly, and management of the SGA was reliably executed according to a thorough preoperative plan. The mean surgical time and intraoperative blood loss were 224.4 min and 1250 ml, respectively. Among the eight patients, four underwent anatomic reduction and five had excellent functional outcomes at the final follow-up. No significant complications occurred.ConclusionsThis 3D skeleton-arterial model is helpful for orthopedists in preoperative planning and intraoperative assistance.

Accuracy of osteotomy using patient specific instrumentation in total knee arthroplasty with minimally invasive surgery

Accuracy of osteotomy using patient specific instrumentation in total knee arthroplasty with minimally invasive surgery

Navigation-Assisted Nasal Bone Osteotomy for Malunited Fracture.

Nasal bone osteotomy subjectively judges the position for osteotomy by visual inspection and by manual feel using the fingertip. Therefore, the outcome depends on the surgeon's experience and mastery of the procedure is technically challenging. The authors applied a navigation system for the intraoperative evaluation of the osteotomy line and reduction position in 5 patients with malunited nasal bone fracture. The authors performed the operation with a temporal bone post developed for otologic surgery using Stealth Station S7 System (Medtronic, Minneapolis, MN). The suretrack is attached to the bone chisel. The authors performed the osteotomies while visualizing the tip of the chisel on the monitor.In addition, evaluation of the reduction position was performed by insertion of a 23G needle syringe with the suretrack to the nasal bone surface. The tip of the bone chisel was visible on the monitor, and the authors could perform osteotomies while confirming the position and direction of osteotomy. In addition, the reduction position could be visualized clearly on the monitor. Navigation systems can confirm the 3-dimensional spatial relationship around the fracture site in real time, requiring only comparatively simple preoperative preparation and intraoperative operation without radiation exposure. Therefore, the advantage is that even an inexperienced surgeon can perform an accurate evaluation. This would be useful as a guide for young doctors and medical students as it would be possible to perform safe and accurate osteotomy for old nasal bone fractures.

Clinical Outcome of Total Knee Arthroplasty Performed Using Patient-Specific Cutting Guides.

BackgroundPatient-specific instruments have recently gained attention for ensuring the accuracy of osteotomy and correct alignment in total knee arthroplasty (TKA). We aimed to report our experience with TKA performed by using CT-based 3D model of cutting guides in our clinic.Material/MethodsA total of 36 patients (mean age, 67.58±8.46 years; 24 females, 12 males) who underwent TKA with 3D patient-specific cutting guides in our clinic were included in the study. Differences between preoperatively planned bone resections and actual bone resections were calculated. Femoral and tibial component angles were measured on radiographs of the knee. The change in knee pain was evaluated by patients on a 10-point visual analog scale (VAS). Patients were followed up for 6 months postoperatively.ResultsThe actual bone resection was 0.5–1.5 mm higher than the planned resection for all sides, being statistically significant for posterior lateral and distal medial sides (1.1±1.3 mm and 1.5±0.9 mm, respectively; p<0.05). On postoperative radiographs, coronal tibial component angle was 88.8°±0.9° and coronal femoral component angle was 95.2°±1.6°, showing good postoperative alignment. The VAS pain score of patients significantly decreased from preoperative 3.9±0.8 to 1.1±0.9 at 6 months after the operation. One patient developed superficial tissue infection on postoperative follow-up, which was effectively treated. No other pathology was detected in the postoperative period.ConclusionsPatient-specific cutting guides can provide intraoperative guidance for better placement of the implant in TKA and increase the accuracy of osteotomy and postoperative alignment.

Application of 3D printing osteotomy plate in osteotomy for correction of cubitus varus in children

Objective To study the application value of 3D printing osteotomy plate technique in the correction of cubitus varus deformity in children. Methods From July 2014 to December 2015, 7 patients with cubitus varus deformity were treated with wedge-shaped osteotomy of lateral humeral supracondylar. Before surgery thin-section CT scan and elbow joint three-dimensional reconstruction were performed. According to the cubitus varus situation, the best osteotomy angle was designed and then a guide plate was established which was anatomically consistent with the osteotomy range. Three-dimensional data model of the guide plate were input into 3D printer for producing guide plate. During the operation, the established guide plate of osteotomy was matched with the part of humeral osteotomy. After osteotomy along the plate, the osteotomy gap was slowly closed and fixed by plate. Results The osteotomy angle was satisfactory in 7 cases after operation. Postoperative follow-up time ranged from 3 to 6 months with an average of 4 months. The elbow function was evaluated according to the Mayo elbow function score. The results were excellent in 5 cases, good in 1 case and fair in 1 case. Conclusion The osteotomy plate which is 3D printed can provide a personalized and accurate osteotomy for correction of cubitus varus deformity in children. Key words: Elbow joint; Osteotomy; Cubitus varus; 3D printing