To further incorporate computer-aided designs to improve preoperative planning in total hip arthroplasty: a cohort study.

Background: Hip replacement surgeries are increasing in demand, requiring rigorous improvements to a mature surgical protocol. Postoperative patient dissatisfaction mainly stems from postoperative complications resulting from the inappropriate selection of prostheses to meet the needs of each patient. This results in prosthesis loosening, hospital-related fractures, and postoperative complex pain, which can all be attributed to inappropriate sizing. In this study, we aimed to further explore the intraoperative and postoperative benefits of incorporating computer-aided design (CAD) in preoperative planning for total hip arthroplasty (THA). Methods: A total of 62 patients requiring total hip replacement surgery from January 2021 to December 2021 were collected and randomly divided into a preoperative computer-aided simulated group and a conventional x-ray interpretation group. The accuracy of implant size selection (femoral and acetabular implant) between the preoperative planning and surgical procedure of the two groups was compared. Patient parameters, perioperative Harris hip scores, operative time (skin-to-skin time), surgical blood loss, and postoperative hospital stay were recorded, and the differences between the two groups were statistically compared using a single sample t-test. Results: All patients in the study were successfully operated on and achieved good postoperative functional recovery. With CAD, the selection of the most suitable-sized prosthesis was significantly more accurate compared to the control group (accuracy of the acetabular component between the CAD/control: 80.6%/61.3%, and accuracy of the femoral component: 83.9%/67.7%). Intraoperative blood loss (177.4/231.0 ml, P = 0.002), operation time (84.2 ± 19.8 min/100.3 ± 25.9 min, P = 0.008), duration of hospital stay (6.5 ± 3/9.1 ± 3.9 days, P = 0.003), and postoperative Harris hip score (81.9 ± 6.5/74.7 ± 11.1, P = 0.003) were compared to the control group and showed statistical significance. Conclusion: Incorporating CAD into the preoperative planning of total hip arthroplasty can effectively guide the selection of the most suitable-sized prosthesis, reduce intraoperative blood loss, and promote short-term functional recovery after THA.

Computer-aided design and 3D printing for a stable construction of segmental bone defect model in Beagles: a short term observation.

OBJECTIVE: Segmental bone defect animal studies require stable fixation which is a continuous experimental challenge. Large animal models are comparable to the human bone, but with obvious drawbacks of housing and costs. Our study aims to utilize CAD and 3D printing in the construction of a stable and reproducible segmental bone defect animal mode. METHODS: CAD-aided 3D printed surgical instruments were incorporated into the construction of the animal model through preoperative surgical emulation. 20 3D printed femurs were divided into either experimental group using 3D surgical instruments or control group. In Vitro surgical time and accuracy of fixation were analysed and compared between the two groups. A mature surgical plan using the surgical instruments was then utilized in the construction of 3 segmental bone defect Beagle models in vivo. The Beagles were postoperatively assessed through limb function and imaging at 1, 2 and 3 months postoperatively. RESULTS: In vitro experiments showed a significant reduction in surgical time from 40.6 ± 14.1 (23-68 min) to 26 ± 4.6 (19-36 min) (n = 10, p < 0.05) and the accuracy of intramedullary fixation placement increased from 71.6 ± 23.6 (33.3-100) % to 98.3 ± 5.37 (83-100) %, (n = 30, p < 0.05) with the use of CAD and 3D printed instruments. All Beagles were load-bearing within 1 week, and postoperative radiographs showed no evidence of implant failure. CONCLUSION: Incorporation of CAD and 3D printing significantly increases stability, while reducing the surgical time in the construction of the animal model, significantly affecting the success of the segmental bone defect model in Beagles.

Synergetic Effects of Nanoscale ALD-HfO2 Coatings and Bionic Microstructures for Antiadhesive Surgical Electrodes: Improved Cutting Performance, Antibacterial Property, and Biocompatibility.

The high temperature induced by surgical electrodes is highly susceptible to severe surface adhesion and thermal damage to adjacent tissues, which is a major challenge in improving the quality of electrosurgery. Herein, we reported a coupled electrode with micro/nano hierarchical structures fabricated by depositing nanoscale hafnium oxide (HfO2) coatings on bionic microstructures (BMs) via laser texturing, acid washing, and atomic layer deposition (ALD) techniques. The synergistic effect of HfO2 coatings and BMs greatly enhanced the hemophobicity of the electrode with a blood contact angle of 162.15 ± 3.16°. Furthermore, the coupled surface was proven to have excellent antiadhesive properties to blood when heated above 100 °C, and the underlying mechanism was discussed. Further experiments showed that the coupled electrode had significant advantages in reducing cutting forces, thermal damage, and tissue adhesion mass. Moreover, the antibacterial rates against Escherichia coli and Staphylococcus aureus were 97.2% and 97.9%, respectively. In addition, the noncytotoxicity levels of HfO2 coatings were verified by cell apoptosis and cycle assays, indirectly endowing the coupled electrode with biocompatibility. Overall, the coupled electrode was shown to have broad potential for application in the field of electrosurgery, and this work could provide new insights into antiadhesion properties under high-temperature conditions.

3D printed strontium-doped calcium phosphate ceramic scaffold enhances early angiogenesis and promotes bone repair through the regulation of macrophage polarization.

The vascularization of bone repair materials is one of the key issues that urgently need to be addressed in the process of bone repair. The changes in macrophage phenotype and function play an important role in the process of vascularization, and endowing bone repair materials with immune regulatory characteristics to enhance angiogenesis is undoubtedly a new strategy to improve the effectiveness of bone repair. In order to improve the effect of tricalcium phosphate (TCP) on vascularization and bone repair, we doped strontium ions (Sr) into TCP (SrTCP) and prepared porous 3D printed SrTCP scaffolds using 3D printing technology, and studied the scaffold mediated macrophage polarization and subsequent vascularization and bone regeneration. The results of the interaction between the scaffold and macrophages showed that the SrTCP scaffold can promote the polarization of macrophages from M1 to M2 and secrete high concentrations of VEGF and PDGF-bb cytokines, which shows excellent angiogenic potential. When human umbilical vein endothelial cells (HUVECs) were co-cultured with macrophage-conditioned medium of SrTCP scaffold, HUVECs exhibited excellent early angiogenesis-promoting effects in terms of scratch healing, angiogenic gene expression, and in vitro tube formation performance. The results of in vivo bone repair experiments showed that the SrTCP scaffold formed a vascular network with high density and quantity in the bone defect area, which could increase the rate of new bone formation and advance the period of bone formation, and finally achieved a better bone repair effect. We observed a cascade effect in which Sr-doped SrTCP scaffold regulate macrophage polarization to enhance angiogenesis and promote bone repair, which may provide a new strategy for the repair of clinical bone defects.

Feasibility of Computer-Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates.

OBJECTIVE: To evaluate the feasibility and utility of computer-aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators. METHODS: In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction-consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T-test. RESULTS: The mean limb lengthening achieved was 6.41 ± 2.54 (range, 3.30-10.54) cm with either varus or valgus correction. The mean operative duration was 151 ± 41.87 (84-217) minutes and mean blood loss was 53.58 ± 22.51(25-87) ml. The mean distraction-consolidation time was 3.67 ± 1.13 (range, 2.5-6.0) months and mean external fixator duration was 11 ± 2.45 (range, 8-14) months. The mean healing index (HI) was 18.11 ± 3.58 (range, 12.8-22.7) days/cm. Mean LEFS scores improved postoperatively from 32.17 ± 8.57 (range, 24-45) to 61.17 ± 6.68 (range, 50-67) with a significant difference (T = -14.26,P < 0.001). CONCLUSIONS: Simultaneous length and angular correction can be achieved by incorporating CAD into the surgical treatment of patients with LLD, without compromising postoperative lower limb function. CAD demonstrates utility in the surgical treatment of LLD by improving the functionality of monorail external fixators.

Preliminary application of 3D-printed individualised guiding templates for total hip arthroplasty in Crowe type IV developmental dysplasia of the hip.

OBJECTIVE: To evaluate the feasibility and accuracy of three-dimensional (3D)-printed individualised guiding templates in total hip arthroplasty (THA) for the treatment of developmental dysplasia of the hip (DDH). METHODS: 12 hips in 12 patients with Crowe type IV DDH were treated with THA. A 3D digital model of the pelvis and lower limbs was reconstructed using the computed tomography data of the patients. Preoperative surgical simulations were performed to determine the most suitable surgical planning, including femoral osteotomy and prosthesis placement. Based on the ideal surgical planning, individualised guiding templates were designed by software, manufactured using a 3D printer, and used in acetabulum reconstruction and femoral osteotomy during surgery. RESULTS: 12 patients were followed up for an average of 72.42 months (range 38-135 months). During surgery, the guiding template for each case was matched to the bony markers of the acetabulum and proximal femur. Preoperative and follow-up Harris Hip Scores were 34.2 ± 3.7 and 85.2 ± 4.2; leg-length discrepancy, 51.5 ± 6.5 mm and 10.2 ± 1.5 mm; and visual analogue scale scores, 6.2 ± 0.8 and 1.3 ± 0.3, respectively, with statistical difference. Shortened deformity and claudication of the affected limb were obviously improved after surgery. However, 1 patient had artificial hip dislocation 2 weeks after surgery, and another patient had sciatic nerve traction injury, both of whom recovered after physical treatment. CONCLUSIONS: Preoperative surgical simulation and 3D-printed individualised guiding templates can fulfil surgeon-specific requirements for the treatment of Crowe type IV DDH. Accurate THA can be achieved using 3D-printed individualised templates, which provide a new personalised surgical plan for the precise positioning and orientation of acetabular reconstruction and femoral osteotomy.

Three-Dimensional Printing Technology for Surgical Correction of Congenital Scoliosis Caused by Hemivertebrae.

OBJECTIVE: This study aimed to explore the clinical application of three-dimensional (3D) printing technology in the surgical treatment of congenital scoliosis caused by hemivertebrae. METHODS: Twenty-four patients (11 in the 3D-printing group and 13 in the conventional group) with scoliosis secondary to a single hemivertebra were retrospectively reviewed. All patients underwent hemivertebrectomy and short-segment fixation. Virtual preoperative planning, operation simulation, and intraoperative application of 3D-printed patient-specific templates were performed in the 3D-printing group. Hemorrhage volume, operation time, transfusion, and complications were noted. Radiographic parameters were evaluated preoperatively, postoperatively, and at final follow-up. RESULTS: All patients had different degrees of successfully corrected scoliosis. There was a similar correction of the Cobb angle postoperatively between the 2 groups. The operation time, blood loss, transfusion, time for the insertion of each screw, accuracy of screw placement, and complication rate in the 3D-printing group were significantly superior to those in the control group. No patient experienced major complications. No significant correction loss or instrument dysfunction was observed during follow-up. CONCLUSIONS: As a viable and effective auxiliary technology, 3D printing makes it possible for surgery to meet both surgeon-specific and patient-specific requirements. 3D-printed individualized templates allow surgery for the correction of congenital scoliosis to enter a new stage of personalized precision surgery.

Controlled degradation of chitosan-coated strontium-doped calcium sulfate hemihydrate composite cement promotes bone defect repair in osteoporosis rats.

Strontium (Sr)-doped calcium sulfate hemihydrate (SrCSH) bioactive materials have been demonstrated to promote osteoporotic bone repair, being associated with the stimulation of bone formation and a reduction in bone resorption. However, the rapid degradation and absorption of SrCSH affects its clinical value. In order to delay the degradation time of SrCSH and improve the utilization of Sr2+, chitosan (CS)-coated SrCSH microspheres (CS-SrCSH) are prepared by electrostatic interaction between CS and SrCSH. X-ray diffraction analysis verifies that SrCSH coated by CS does not alter the phase composition of the SrCSH. It was observed that CS-SrCSH microspheres have uniform particle size. More importantly, the in vivo and in vitro degradation time of CS-SrCSH microspheres is significantly longer than that of SrCSH, and the release rate of Sr2+ is stable, achieving a sustained release effect. Furthermore, CS-SrCSH-based cement is used to repair critical-sized OVX rat tibial defects. The in vivo results reveal that CS-SrCSH exhibits a long-term capability for osteogenesis, angiogenesis and bone metabolism inhibition. In conclusion, the controllable degradation of CS-SrCSH-based cements described here could be beneficial for the repair of bone defects, especially in the osteoporotic bone.

Three-Dimensional-Printed Individualized Guiding Templates for Surgical Correction of Severe Kyphoscoliosis Secondary to Ankylosing Spondylitis: Outcomes of 9 Cases.

OBJECTIVE: To report the outcomes of severe kyphoscoliosis secondary to ankylosing spondylitis (AS) corrected with 3D-printed individualized guiding templates. METHODS: Computed tomography (CT) data of patients with severe kyphoscoliosis secondary to AS were used to reconstruct 3D models of the spine and to develop a surgical plan. An asymmetric wedge pedicle subtraction osteotomy (PSO) was simulated using medical computer design software. Before the actual surgery, continual surgical simulations were performed until the most suitable one was obtained, and personalized guiding templates were manufactured for the anticipated PSO. During operation, the osteotomy plane and trajectories for the pedicle screws were positioned by the designed patient-specific 3D-printed guiding templates. RESULTS: In this study, we reviewed 9 patients who underwent correction of kyphoscoliosis using a 3D-printed individualized guiding template and were followed for a median of 21.4 months (range, 9-36 months). The average correction at the site of osteotomy was 65.9°. No patient experienced severe complications, such as misplaced pedicle screws or neurologic complications. At the last follow-up, no patient exhibited implant dysfunction on radiography. CONCLUSIONS: Preoperative surgical simulation using 3D-printed templates is a viable technique that enables surgery to meet both patient- and surgeon-specific requirements for correction of severe thoracolumbar kyphoscoliosis. These 3D-printed templates can guide the performance of planned PSO to provide functional restoration of severe kyphoscoliosis secondary to AS.

[Precise orthormorphia of tibial angulation deformity and shortening deformity by using digital technology combined with circular external fixator].

Objective: To evaluate the effectiveness of precise orthormorphia of tibial angulation deformity and shortening deformity by using digital technology combined with external fixator. Methods: Twenty-six cases of tibial angulation deformity combined with shortening deformity were treated between June 2012 and August 2016, including 12 males and 14 females aged from 1 to 19 years with an average age of 16.5 years. There were 6 cases of congenital patella pseudoarthrosis, 1 case of fibrous dysplasia of femur and tibia, 3 cases of limb shortening deformity caused by infantile paralysis, 16 cases of fracture malunion. Limb shortening was 1.5-9.5 cm (mean, 6.2 cm) before operation. The deformity from three-dimensional perspective was analysed by digital technology, the surgical procedures of lengthening and osteotomy was simulated, the navigation templates were completed with computer aided design (CAD) and three-dimensional printing, and the external fixator was used to assist the lengthening of the tibia. X-ray films were regularly reviewed after operation to observe the new bone remolding, limb lengthening, load bearing line of lower limb, and recurrences of angulation. Results: All the patients were followed up 14-48 months (mean, 18.8 months). There was only 1 case of superficial pin site infection which was cured with oral antibiotics and pin site care with mild disinfectants, and no complication such as bone nonunion, equines deformity, or vascular nerve injury occurred. The deformity of tibia and load bearing line of lower limb had been completely recovered according to postoperative X-ray films at 1 week. All the cases achieved perfect limb length as with preoperative design. The bone mineralization time was 12-20 weeks (mean, 11.6 weeks), the external fixator removal time was 18-26 weeks (mean, 14.9 weeks), and the healing index was 21-78 d/cm (mean, 63.4 d/cm). The postoperative flexion range of the injured limb was 15° less than the unaffected extremity in 1 case, and the situation was improved significantly after some physical manipulation and exercise, who completed the limb lengthening and achieved the expected effectiveness finally. Conclusion: Precise orthormorphia of tibial deformity by using digital technology, and limb lengthening with the aid of external fixator can achieve good effectiveness with good reliability, invasiveness, and precision.

[Preliminary application of three dimensional printing personalized navigation template in assisting total elbow replacement for patients with elbow tumor].

Objective: To explore the clinical methods of resection of elbow tumor and total elbow replacement with custom personalized prosthesis based on three dimensional (3-D) printing navigation template. Methods: In August 2016, a 63-year-old male patient with left elbow joint tumor was treated, with the discovery of the left distal humerus huge mass over 3 months, with elbow pain, activity limitation of admission. Computer-assisted reduction technique combined with 3-D printing was used to simulate preoperative tumor resection, a customized personal prosthesis was developed; tumor was accurately excised during operation, and the clinical result was evaluated after operation. Results: The time was 46 minutes for tumor resection, and was 95 minutes for personalized implant and allograft bone without fluoroscopy. X-ray and CT examination at 1 week after operation showed good position of artificial elbow joint; the anteversion of ulna prosthesis was 30° and the elbow carrying angle was 15°, which were consistent with the simulated results before surgery. The finger flexion was normal at 1 month after operation; the range of motion was 0-130° for elbow flexion and extension, 80° for forearm pronation, and 80° for forearm supination. The elbow function was able to meet the needs of daily life at 7 months after operation, and no recurrence and metastasis of tumor were observed. Conclusion: For limb salvage of elbow joint, computer aided design can make preoperative surgical simulation; the navigation template can improve surgical precision; and the function of elbow joint can be reconstructed with customized and personlized prosthesis for total elbow replacement.

Pedicle screw fixation with kyphoplasty decreases the fracture risk of the treated and adjacent non-treated vertebral bodies: a finite element analysis.

Adjacent vertebral fractures are common in patients with osteoporotic vertebral compression fractures (OVCFs) after kyphoplasty. This finite element study was to examine whether short segment pedicle screw fixation (PSF) with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae after kyphoplasty for OVCFs. By simulating cement augmentation with or without short segment pedicle screw fixation (PSF), two tridimensional, anatomically detailed finite element models of the T10-L2 functional spinal junction were developed. The insertion of pedicle screws into the intact vertebra apparently decreased the stress distribution of the treated vertebra in vertical compression and other load situations. The stress distribution in the bone structures of the intact vertebra adjacent to the intact-screwed vertebra was much less than that in the one adjacent to the treated vertebra. The insertion of pedicle screws into the intact vertebra greatly decreased the maximum displacement of the cortical bones and cancellous bones of the vertebrae. Our results indicated that short segment PSF with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae in the management of OVCFs.

[PRELIMINARY APPLICATION OF THREE-DIMENSIONAL PRINTING PERSONALIZED EXTERNAL FIXATOR IN SERIOUS TIBIOFIBULA FRACTURES].

OBJECTIVE: To explore a new method of treating serious tibiofibula comminuted fracture by using three-dimensional (3-D) printing personalized external fixator. METHODS: In April 2015, a male patient (aged 18 years with a height of 171 cm and a weight of 67 kg) with left tibiofibula comminuted fracture was included in the study. Computer-assisted reduction technique combined with 3-D printing was used to develop a customised personalized external fixator for fracture reduction. The effectiveness was observed. RESULTS: The operation time was about 10 minutes without fluoroscopy, and successful reduction was obtained. The patient had equal limb length after operation. X-ray films showed that the posterior angulation of distal fracture was corrected 37 degrees, and the eversion angle was corrected 4 degrees. The tibial fractures had good paraposition or alignment, and the lower limb force line was corrected completely. No new fracture displacement occurred. The clinical healing time of fracture was 3.5 months and the bone union was achieved after 8 months. The function of affected limb recovered well after operation. CONCLUSION: A personalized external fixator for serious tibiofibula comminuted fracture reduction made by 3-D printing technique has the merits of easy manipulation, high individuation, accurate reduction, stable fixation, and no need of fluoroscopy.

[Effect of three-dimensional printing navigation templates assisting reconstruction with personalized unrestricted total knee prosthesis for treating maliganant bone tumors around knees].

OBJECTIVE: ?To evaluate the effectiveness of three-dimensional (3D) printing navigation templates assisting reconstruction with personalized unrestricted total knee prosthesis to treat maliganant bone tumors around the knee. METHODS: ?Between March 2007 and September 2014, 43 patients with malignant tumor around the knee were divided into 2 groups: 3D printing navigation templates assisting reconstruction with personalized unrestricted total knee prosthesis were used in 21 cases (trial group), and conventional tumor resection and reconstruction with hinged total knee prosthesis were used in 22 cases (control group). There was no significant difference in age, gender, tumor location, pathological diagnosis, tumor stage, diameter of tumor, disease duration, and preoperative visual analogue scale (VAS) score between 2 groups (P>0.05), which were comparable. Intraoperative length of tumor resection and blood loss were recorded and compared, and the postoperative complications and tumor recurrence were observed. The Musculoskeletal Tumor Society (MSTS) score was used to evaluate knee joint function. RESULTS: ?The operations were completed successfully in the patients of 2 groups and postoperative pathological results were negative in tumor resection margin. All the patients were followed up 12-77 months (mean, 36.7 months). There was no significant difference in the length of tumor resection and blood loss between trial group and control group (t=1.01, P=0.32; t=-0.76, P=0.45). In trial group, the resection range and reconstruction results were consistent with preoperative computer simulation; postoperative complications happened in 2 cases (9.52%); 1 case of immunological rejection and 1 case of infection); 2 cases (9.52%) had recurrence of osteosarcoma and pulmonary metastasis at 1 year after operation. In the control group, complication occurred in 6 cases (27.27%; 2 cases of periprosthetic fractures, 2 cases of infection, 1 case of incision nonunion, and 1 case of common peroneal nerve injury); 4 cases (18.18%) had recurrence of osteosarcoma and metastasis at 1 year after operation. There was no significant difference in postoperative complication and recurrence rate between 2 groups (χ2=2.24, P=0.14; χ2=0.67, P=0.41). At last follow-up, distal femur score of tumor and proximal tibial score of tumor in trial group were significantly better than those in control group (t=4.89, P=0.00; t=3.94, P=0.00). The mean flexion and extension range of motion of the knee joint was (115.45±12.25)° in trial group and was (101.49±11.96)° in control group, showing significant difference (t=3.78, P=0.00). CONCLUSIONS: ?The effectiveness using 3D printing navigation templates assisting reconstruction with personalized unrestricted prosthesis for maliganant bone tumors around the knee is better than conventional tumor resection and reconstruction with hinged total knee prosthesis. It can improve the joint function better and the patients' quality of life.

Computer-aided resection and endoprosthesis design for the management of malignant bone tumors around the knee: outcomes of 12 cases.

BACKGROUND: To report the outcomes of computer-aided resection and endoprosthesis design for the management of malignant bone tumors around the knee. METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) data were input into computer software to produce three-dimensional (3D) models of the tumor extent. Imaging data was then used to create a template for surgical resection, and development of an individualized combined allogeneic bone/endoprosthesis. Surgical simulations were performed prior to the actual surgery. RESULTS: This study included 9 males and 3 females with a mean age of 25.3 years (range, 13 to 40 years). There were 9 tumors in the distal femur and 3 in the proximal tibia. There were no surgical complications. In all cases pathologically confirmed clear surgical margins were obtained. Postoperative radiographs showed the range of tumor resection was in accordance with the preoperative design, and the morphological reconstruction of the bone defect was satisfactory with complete bilateral symmetry. The mean follow-up time was 26.5 months. Two patients died of their disease and the remaining are alive and well without evidence of recurrence. All patients are able to ambulate freely without restrictions. At the last follow-up, the average International Society of Limb Salvage score was 25.8 (range, 18 to 27), and was excellent in 8 cases and good in 4 cases. CONCLUSIONS: Computer-aided design and modeling for the surgical management of bone tumors and subsequent limb reconstruction provides accurate tumor removal with the salvage of a maximal amount of unaffected bone and precise endoprosthesis reconstruction.

[Computer-aided precise resection of pelvic tumor and function reconstruction].

OBJECTIVE: To investigate the value of computer-aided design (CAD) in defining the resection boundary, reconstructing the pelvis and hip in patients with pelvis tumors. METHODS: Between November 2006 and April 2009, 5 cases of pelvis tumors were treated surgically using CAD technology. There were 3 males and 2 females with an average age of 36.4 years (range, 24-62 years). The cause was osteosarcoma, giant cell tumor of bone, and angiosarcoma in 1 case, respectively, and chondrosarcoma in 2 cases. According to the Enneking system for staging benign and malignant musculoskeletal tumors, regions I, I + II, III, IV, and I + IV is in 1 case, respectively. According to the principle of reverse engineering, 5 patients with pelvis tumors were checked with lamellar CT/MRI scanning, whose two-dimensional data were obtained in disease area. The three-dimensional reconstruction of pelvic anatomical model, precise resection boundary of tumor, individual surgical template, individual prosthesis, and surgical simulation were precisely made by computer with CAD software. Based on the proposal of CAD, the bone tumor was resected accurately, and allograft ilium with internal fixation instrument or allogeneic ilium with personalized prosthetic replacement were used to reconstruct the bone defect after tumor was resected. RESULTS: The operation was successfully performed in 5 cases. The average operation time was 7.9 hours, and the average blood loss was 3 125 mL. Hemorrhage and cerebrospinal fluid leakage occurred in 1 case, respectively, and were cured after debridement. Five patients were followed up from 24 to 50 months (mean, 34.5 months). All patients began non-weight bearing walk with double crutches at 4-6 weeks after operation, and began walk at 3-6 months after operation. Local recurrence developed in 2 patients at 18 months after operation, and resection and radiotherapy were performed. According to International Society of Limb Salvage criteria for curative effectiveness of bone tumor limb salvage, the results were excellent in 2 and good in 3. CONCLUSION: The individual surgical template, individual prosthesis, and surgical simulation by CAD ensure the precision and reliability of pelvis tumors resection. The CAD technology promotes pelvis tumor resection and the reconstruction of pelvis to individual treatment stage, and good curative effectiveness can be obtained.

[Research on direct forming of comminuted fracture surgery orienting model by selective laser melting].

In order to simplify the distal femoral comminuted fracture surgery and improve the accuracy of the parts to be reset, a kind of surgery orienting model for the surgery operation was designed according to the scanning data of computer tomography and the three-dimensional reconstruction image. With the use of DiMetal-280 selective laser melting rapid prototyping system, the surgery orienting model of 316L stainless steel was made through orthogonal experiment for processing parameter optimization. The technology of direct manufacturing of surgery orienting model by selective laser melting was noted to have obvious superiority with high speed, precise profile and good accuracy in size when compared with the conventional one. The model was applied in a real surgical operation for thighbone replacement; it worked well. The successful development of the model provides a new method for the automatic manufacture of customized surgery model, thus building a foundation for more clinical applications in the future.

[Clinical analysis of treating 164 cases of tendon and ligament injuries with allograft tendon].

OBJECTIVE: To research the operative method and the clinical efficacy of repairing and reconstructing tendon and ligament with allograft tendon. METHODS: From September 2000 to May 2007, 164 cases with tendon and ligament injuries were treated, including 116 males and 48 females aged 21-47 years old (average 31.5 years old). There were 126 cases of anterior cruciate ligament injury, 18 cases of complete acromioclavicular dislocation, 10 cases of old dislocation of radial head, 4 cases of Achilles tendon rupture, 2 cases of tibialis anterior muscle rupture, 2 cases of patellar tendon rupture, and 2 cases of rectus femoris rupture. Time interval between injury and hospital admission was 4-345 days (average 75 days). Allograft tendon 10-26 cm in length with suture anchor or absorbable interference screw was used to reconstruct the ligament and tendon. RESULTS: All wounds healed by first intention, except one case of rectus femoris rupture. All patients were followed for 10-36 months (average 21 months). The international knee documentation committee and the Lysholm score of patients with anterior cruciate ligament injury 12 months after operation were significantly higher than that of before operation (P < 0.01). According to the Lazzcano and Karlsson score standard, 13 cases of complete acromioclavicular dislocation at 10-12 months after operation were graded as excellent and 5 cases were good. According to Arner Lindholm score standard, 3 cases of Achilles tendon rupture at 8-16 months after operation were graded as excellent and 1 case was good. For the patients with tibialis anterior muscle rupture, at 10-17 months after operation, the limitation of dorsal extension in ankle joint was 5 degrees, and the muscle strength in the anterior tibialis muscle was decreased. For the patients with patellar tendon rupture, one completely restored the motion range of the knee joint 14 months after operation, the other had knee extension limitation of 10 degrees at 13 months after operation. For the patients with rectus femoris rupture, one had 15 degrees of extension limitation at 18 months after operation, the other suffered limitation of both extension and genuflex at 12 months after operation. According to the Broberg-Morrey score standard, 7 cases with old dislocation of radial head were graded as excellent and 3 cases were good at 3-36 months after operation. CONCLUSION: Allograft tendon is a good material for repairing and reconstructing tendon and ligament injuries, but attention should be paid to postoperatively early exercise under appropriate protection and early management of local rejection.

[Preparation of cisplatin-impregnated coral hydroxyapatite drug delivery system].

OBJECTIVE: To prepare a cisplatin-impregnated coral-derived hydroxyapatite (CCHA) drug delivery system (DDS), and evaluate its inhibitory effect on human osteosarcoma cells U-2 OS, human breast cancer and prostatic carcinoma cells PC-3 in vitro. METHODS: The coral-derived hydroxyapatite (CHA) was manufactured by hydrothermal exchange and impregnated with cisplatin by vacuum freeze-drying techniques. The leaching solutions of this DDS was collected at different intervals in a course of 8 weeks and their inhibitory effect on the cells was tested in vitro by MTT assay. RESULTS: Electron microscope showed that cisplatin was distributed homogeneously in the pores of CHA. The inhibition rates of the leaching solution on all the tumor cells exceeded 50% except for PC-3 cells, whose inhibition rate was 29.92% when treated with the solution collected at the eighth week. CONCLUSION: CCHA allows sustained drug release and maintains excellent inhibitory effect on human bone tumor cells within 8 weeks in vitro.

[Recent development of computer-aided tissue engineering].

OBJECTIVE: To introduce the recent advances of the application of computer technology in tissue engineering. METHODS: The recent original articles related to computer technology, medical image technology, computer-aided design, the advanced manufacture technology were summarized and systematically analyzed. RESULTS: Computer-aided tissue engineering is a new field on tissue engineering. It is the future direction of tissue engineering study. This article reviews recent development of medical CT/MRI scanning, three-dimensional reconstruction, anatomical modeling, computer-aided design, computer-aided manufacturing, rapid prototyping, RP manufacturing of tissue engineering scaffolds and computer-aided implantation. CONCLUSION: Computer-aided tissue engineering can be used in scaffolds design and fabrication, computer-aided artificial tissue implantation. It is a new field on tissue engineering.