3D printed orthopedic insoles for flatfoot: a systematic review / 中国康复理论与实践

ObjectiveTo review the classification of orthopedic insoles, common techniques of 3D printing orthopedic insoles, common materials and their application for flatfoot. MethodsLiteratures were retrieved from PubMed, Web of Science, CNKI and Wanfang Data from 2012 to 2022, and the relevant contents were summarized. ResultsA total of ten studies were finally included, from 5 countries, involving 290 participants, which published from 2019 to 2022. Orthotic insoles were classified as prefabricated, semi-custom, and custom, while custom ones were classified as traditional custom and 3D printed custom. 3D printed orthotic insoles were often made with selective laser sintering, fused deposition modeling (FDM) and PolyJet printing technologies, and commonly used materials included ethylene-vinyl acetate (EVA), polylactic acid, thermoplastic polyurethane, polyamide, and polypropylene. For flatfoot, 3D printed orthotic insoles could improve plantar pressure, relieve foot pain and the combined use of insole posting could control rearfoot valgus. Conclusion3D printed custom insoles can be made more efficiently and accurately than traditional custom insoles. The printing technologies and materials often chosen for 3D printed orthotic insoles are mainly FDM and EVA. 3D printed orthotic insoles is effective on plantar pressure, comfort and foot movement function of flatfoot.

Topological Structure and Biomechanics of Three-Dimensional Printed Height Increasing Insoles for Leg Length Discrepancy / 医用生物力学

Objective To study topological structure of a new type of three-dimensional (3D) printed height increasing insoles for leg length discrepancy (LLD) and its effect on biomechanics of lower limbs. Methods Topological structure for middle and rear part of the insole was optimized by solid isotropic microstructures with penalization (SIMP), the force was loaded and the boundary conditions were set according to force area of the insole, and the height increasing insole with thermoplastic polyurethanes (TPU) materials was printed by selected laser sintering (SLS). The insoles were used in 9 patients with LLD, visual analogue scale (VAS) and Maryland foot function scores were used to compare pain and foot function changes of patients before and after using the insole, and the 3D gait analysis system was used to compare spatiotemporal parameters and vertical ground reaction force (vGRF) of both lower limbs. Result sAfter the patient wore 3D printed insole, VAS scores decreased, Maryland foot function scores increased, vGRF of both lower limbs decreased, and the difference of cadence, stance phase and swing phase in both lower limbs decreased. Conclusions The 3D printed height increasing insole after topology optimization can improve coordination of lower limb movement, reduce ground impact, relieve pain and improve foot function, thus providing an effective personalized orthopedic plan for LLD treatment in clinic.

Expert Concensus on Triune Personalized Treatment of Pelvic Tumor Based on Three-Dimensional Printing / 医用生物力学

The adjacent anatomy of the pelvis is complicated, with digestive, urinary, reproductive and other organs as well as important blood vessels and nerves. Therefore, accurate resection of pelvic tumors and precise reconstruction of defects after resection are extremely difficult. The development of medical 3D printing technology provides new ideas for precise resection and personalized reconstruction of pelvic tumors. The “triune” application of 3D printing personalized lesion model, osteotomy guide plate and reconstruction prosthesis in pelvic tumor limb salvage reconstruction treatment has achieved good clinical results. However, the current lack of normative guidance standards such as preparation and application of 3D printing personalized lesion model, osteotomy guide plate and reconstruction prosthesis restricts its promotion and application. The formulation of this consensus provides normative guidance for 3D printing personalized pelvic tumor limb salvage reconstruction treatment.

Accuracy evaluation for 3D bone reconstruction based on medical 3D reconstruction software / 中华创伤骨科杂志

Objective@#To investigate the feasibility of an accuracy evaluation method for 3D reconstructed bone model based on 3D reconstruction software Arigin3D Pro.@*Methods@#Pig femurs were used as solid models which were scanned by CT and MRI respectively. The scan data were imported into software Arigin3D Pro for 3D model reconstruction by 3 operators with different reconstruction experience (≤1 year, 2 to 3 years, and ≥4 years, respectively). Each operator reconstructed the femurs 3 times and in each reconstruction measured the diameter of the femoral head, the length of the femur and the width of the knee joint at the distal end of the femur 3 times respectively using software Geomagic Wrap. The above parameters of the solid models were measured using a vernier caliper. The parameter values of reconstructed models and solid models were compared and the differences were analyzed.@*Results@#The measurements by Geomagic Wrap showed deviations between the CT and MRI reconstruction models and the solid models, and the maximum deviation percentages were 1.47% and 1.08%, respectively. The percentages of intra-operater difference ranged from 0.29% to 1.53%; the 3D models reconstructed by operators with different reconstruction experience were not identical.@*Conclusions@#It is a feasible accuracy evaluation method to compare key parameters between the 3D bone model reconstructed by software Arigin3D Pro and the real animal bone. The deviations of 3D reconstructed bone model based on CT and MRI images are acceptable. The accuracy of 3D bone construction is related to the difference in operators.

Accuracy evaluation for 3D bone reconstruction based on medical 3D reconstruction software / 中华创伤骨科杂志

Objective To investigate the feasibility of an accuracy evaluation method for 3D reconstructed bone model based on 3D reconstruction software Arigin3D Pro.Methods Pig femurs were used as solid models which were scanned by CT and MRI respectively.The scan data were imported into software Arigin3D Pro for 3D model reconstruction by 3 operators with different reconstruction experience (≤1 year,2 to 3 years,and ≥4 years,respectively).Each operator reconstructed the femurs 3 times and in each reconstruction measured the diameter of the femoral head,the length of the femur and the width of the knee joint at the distal end of the femur 3 times respectively using software Geomagic Wrap.The above parameters of the solid models were measured using a vernier caliper.The parameter values of reconstructed models and solid models were compared and the differences were analyzed.Results The measurements by Geomagic Wrap showed deviations between the CT and MRI reconstruction models and the solid models,and the maximum deviation percentages were 1.47％ and 1.08％,respectively.The percentages of intra-operater difference ranged from 0.29％ to 1.53％;the 3D models reconstructed by operators with different reconstruction experience were not identical.Conclusions It is a feasible accuracy evaluation method to compare key parameters between the 3D bone model reconstructed by software Arigin3D Pro and the real animal bone.The deviations of 3D reconstructed bone model based on CT and MR1 images are acceptable.The accuracy of 3D bone construction is related to the difference in operators.

Clinical application of intraosseous internal fixation in ankle-foot arthrodesis / 中华创伤骨科杂志

Objective To investigate the short- to medium-term therapeutic effects of a new internal fixation device,intraosseous internal fixation(IO-FIX),in the foot-ankle arthrodesis.Methods From August 2016 to December 2018,32 patients(40 feet) underwent foot-ankle arthrodesis with IO-FIX at Department of Orthopaedic Surgery,The Ninth Peopled Hospital of Shanghai.They were 6 males and 26 females,aged from 23 to 83 years(61.7±15.1 years).There were 28 cases(36 feet) of hallux valgus,2 cases(2 feet) of ankle arthritis,one case(1 foot) of ankle rheumatoid arthritis and one case(1 foot) of naviculocuneiform arthrosis.The therapeutic effects were assessed in terms of imaging evaluation,American Orthopaedic Foot and Ankle Society(AOFAS) score,fusion rate and full weight-bearing time.Results The follow-up ranged from 3.0 to 31.3 months(mean,12.6 months).The total fusion rate was 95.0%(38/40);the total AOFAS score increased significantly from preoperative 41.9±9.5 to postoperative 86.9±4.7(P<0.05).The 28 patients(36 feet) with hallux valgus achieved a successful fusion rate of 97.2%(35/36) and full weight-bearing at 8 weeks after operation.Their fusion time ranged from 45 to 64 days(57.1 days).Their metatarsophalangeal angle was decreased significantly from 52.10±13.50 preoperatively to 13.40±4.90 postoperatively and their 1-2 intermetatarsal angle significantly from 14.5°±2.4°to 8.90±2.4°(P<0.05).Their AOFAS ankle-hindfoot score was improved significantly from 41.8±9.9 to 87.0±4.8(P<0.05).All the 3 cases of ankle arthrodesis achieved good bone union and full weight-bearing within 12 weeks and their AOFAS ankle-hindfoot score was improved significantly from preoperative 43.4±3.5 to 86.3±3.5 at the final follow-up.Conclusion In foot-ankle joint arthrodesis,due to advantages of stable fixation,zero profile,limited soft tissue irritation,reinforced bone bridge and easy reproducibility,10-FIX can lead to satisfactory short- to mid-term therapeutic effects.

Assessment of Gait Stability using Acceleration Signal / 医用生物力学

Objective To analyze human gait stability by acceleration signal at the head and lumbar under different walking conditions, and make comparison with parameters by the traditional COM (center of mass)-COP(center of pressure) method, so as to discuss the reliability of applying wearable sensors to analyze human gait stability. Methods The harmonic ratio (HR) parameter at the head and lumbar based on acceleration signal was applied to analyze gait stability of 18 healthy young adults under 3 walking conditions (footwear normal walking, barefoot normal walking and barefoot walking at different velocities), and the results were compared with the assessment results from the COM-COP method. Results Walking at normal velocity was most stable, with the maximum HR parameter. Compared with footwear walking, HR parameters were significantly decreased (P＜0.05) during barefoot walking, indicating that gait stability was reduced. The results were consistent with the assessment results from the COM-COP method. Considering the factors of walking velocity and footwear, the gait stability parameters obtained by the two methods showed a significant negative linear correlation (R2＞0.50). Lumbar HR parameter and COM-COP parameters showed a stronger linear correlation (R2＞0.65). Conclusions The application of acceleration signal-based analysis algorithm could effectively and reliably evaluate the stability of human gait, and acceleration at the lumbar was more sensitive than the head signal for analyzing gait stability.

Bioactive β-tricalcium phosphate modified by stem cell screen-and-enrich-and-combine circulating system for regeneration of bone defects / 中华创伤骨科杂志

Objective To introduce a new method for preparation of bioactive β-tricalcium phosphate (β-TCP) by rapid stem cell screen-and-enrich-and-combine circulating system (SECCS) and evaluate its efficacy in the treatment of fresh fractures and bone defects.Methods Twenty-two patients with fresh fracture and bone defects were treated with SECCS from July 2013 to April 2016.They were 16 males and 6 females with an average age of 52.2 years (from 27 to 81 years).There were 15 tibial plateau fractures and 7 calcaneal fractures.The average size of bone defects was 12.5 mL.Bioactive β-TCP was prepared by SECCS intraoperatively and implanted back immediately into the bone defects.Radiographic examination,Lysholm knee scoring and Maryland foot scoring were used for assessment of curative efficacy.Results The 22 patients were followed up for an average of 25.7 months (from 12 to 46 months).By SECCS,the enrichment efficiency of bone marrow stromal cells (BMSCs) reached up to 82.4％ and the cell viability was not affected.The tibial plateau fractures were re-transplanted with 13,381.3 BMSCs on average and healed after an average of 8.9 weeks (from 6 to 15 weeks).The Lysholm knee scores at one year postoperatively averaged 93.6 points (from 84 to 100 points),yielding 10 excellent cases,4 good cases and one fair case.The calcaneal fractures were implanted back with 16,677.7 BMSCs on average and healed after an average of 9.4 weeks (from 8 to 13 weeks).The average Maryland foot score at one year after operation was 93.6 points (from 85 to 98 points),yielding 6 excellent cases and one good case.Conclusion Bioactive materials prepared by SECCS are good bone grafts for fresh fractures and bone defects.

Novel bone marrow stem cell Screen-Enrich-Combine(-Biomaterials) Circulating System for limb bone nonunion / 中华创伤骨科杂志

Objective To evaluate the validity and security of our self-designed bone marrow stem cell Screen-Enrich-Combine(-Biomaterials) Circulating System(SECCS) for bone non-union of limbs. Methods From May 2013 to December 2015, 24 patients with limb non-union were treated at our de-partment. They were aged from 20 to 65 years (mean, 42.8 years). Their non-union involved femur in 17 cases, tibia in 4, radius in one, humerus in one and fibula in one. In surgery, 80 mL bone marrow blood was aspirated from the anterior superior iliac spine for rapid preparation of bone substitute(β-TCP)composite with bone marrow stem cells by SECCS which was then implanted at the non-union locations. The bone marrow blood was collected before and after enrichment for stem cell counts. The bone union, clinical union time and related com-plications were evaluated by follow-up X-rays at 1, 3, 6 and 9 months after surgery. Results Each collection of bone marrow blood took 13.5 minutes on average. The enrichment rate of stem cells was 81.2%. 11,751 ± 1,011 stem cells were implanted per patient on average. All the patients were followed up for 9 to 48 months (mean, 19.2 months). Twenty-two patients acquired clinical union 9 months after operation and the other 2 suffered from malunion due to insufficient bone implant, yielding a union rate of 91.6% and an average union time of 6.5 months. No graft infection or internal fixation failure occurred and no severe complications hap-pened at the donor or implant sites.Conclusion The bioactive bone substitute manufactured by our self-designed SECCS can be used as a novel therapy for limb non-union, and this device is moreover charac-terized with convenience, limited invasion and satisfactory osteogenesis so that complications of autologous bone transplantation can be avoided.

Biomechanical properties of cervical traction under neck muscle force / 医用生物力学

Objective To establish a three-dimensional(3D) finite element model of cervical vertebrae (C1-7),and study its biomechanical properties under muscle force by cervical traction,so as to provide references for clinical treatment.Methods On the basis of nonlinear finite element model of normal cervical vertebrae and combined with clinical traction methods,cervical traction at the extension angle of 0°,10°,20°,30°,40° under the same traction weight,was simulated by finite element analysis (FEA) software to obtain and select the joint force and muscle force that were appropriate for FEA on the model.Results In the process of cervical extension by traction,under the muscle force,the average maximum equivalent stress of cervical vertebrae,intervertebral disc and uncovertebral joints increased by 4.86,1.79,0.69 MPa,respectively,and the average maximum relative displacement of cervical vertebrae in sagittal and vertical axis direction increased by 1 1.1,1.26 mm,respectively.The biomechanical properties of cervical traction were similar to the FEA results reported in the literature.Conclusions Neck muscles play an active role in promoting the stress and displacement of cervical vertebrae,intervertebral discs and uncovertebral joints and it should be taken into consideration when performing cervical traction in clinic.In addition,the traction angle should not be too large:0.-20. is generally recommended as a relatively safe angle range at the initial stage.

Biomechanical analysis of a finite element model of rotator cuff / 中华创伤骨科杂志

Objective To establish a finite element model of rotator cuff which can be used to simulate the rotator cuff injury and to evaluate the biomechanical effects of rotator cuff surgery.Methods The Dicom CT images of the right shoulder of a Chinese healthy volunteer were used to establish models of the scapula,humerus and clavicle.The rotator cuff structures were separated and modeled based on the MRI images and anatomical knowledge.After the rotator cuff model was introduced into the finite element analysis software Abaqus 6.12,the anatomical positions were simulated when the shoulder was at 30° internal rotation,30° external rotation,30° abduction,30° adduction,30° flexion and 30° extension.Results When the shoulder was in 30° flexion,the average stress was 52.2 kPa on the supraspinatus,223.0 kPa on the inffaspinatus and the teres minor,and 90.4 kPa on the subscapularis.When the shoulder was in 30° extension,the average stress was 105.0 kPa on the supraspinatus,78.2 kPa on the infraspinatus and the teres minor,and 55.7 kPa on the subscapularis,indicating that the muscle and tendon of the supraspinatus was subjected to greater stress and the humerus and the scapula produced less stress compared with the shoulder in 30° flexion.Conclusion Since our finite element model of the rotator cuff can simulate common activities of the shoulder joint and obtain stress values of the corresponding rotator cuff muscles,it can be used in simulation of rotator cuff injury and its surgery.

Automatic segmentation method for hip joint based on Bayesian Decision Theory / 中国组织工程研究

BACKGROUND:Hip segmentation based on CT image has been widely used in computer-assisted surgery planning, prosthesis design and finite element analysis. OBJECTIVE:To explore application effects of automatic segmentation method for hip joint based on Bayesian Decision Theory in computer-assisted hip surgery. METHODS:An accurate outer surface segmentation and extraction remain chal enging due to deformed shapes and extremely narrow inter-bone regions. In this paper, we present an automatic, fast and accurate approach for segmentation of femoral head and proximal acetabulum. The outline of the femur was segmented and extracted by contrast enhancement, thresholding algorithm and region growth algorithm. The boundaries of the bone regions are further refined based on Bayes decision rule. RESULTS AND CONCLUSION:Automatic segmentation method for hip joint based on Bayesian Decision Theory is an accurate segmentation technique for femoral head and proximal acetabulum and it can be applied in computer-assisted hip surgery and prosthesis design.

Static Balance Evaluated by Maximum Angle of Center of Mass-Center of Pressure in People of Different Ages / 中国康复理论与实践

Objective To compare the difference of static balance ability in different aged people, with the maximum angle of center of mass (COM) and center of pressure (COP). Methods 37 healthy people without cardiovascular and cerebrovascular diseases including 15 young people (18~40 years old), 10 middle age people (41~65 years old) and 12 old people (>65 years old) participated in this study. The maximum angle of COM-COP and the corresponding envelope areas were recorded in 4 standing posture:natural standing, close eyes stand-ing, single leg standing and single leg standing with eyes closed. Results There was no significant difference in the maximum angle of COM-COP among 3 groups in 3 states (nature standing, close eyes standing, single leg standing with eyes closed) (P>0.05), but there was significant difference in the state of single leg standing (P<0.05) between the young and the old, and the middle-aged and the old. Conclu-sion The maximum angle of COM-COP in the state of single leg standing can sensitively detect the deterioration of stability of older people. It may be a new index of static balance in clinic.

Static Balance Evaluated by Maximum Angle of Center of Mass-Center of Pressure in People of Different Ages / 中国康复理论与实践

@#Objective To compare the difference of static balance ability in different aged people, with the maximum angle of center of mass (COM) and center of pressure (COP). Methods 37 healthy people without cardiovascular and cerebrovascular diseases including 15 young people (18~40 years old), 10 middle age people (41~65 years old) and 12 old people (>65 years old) participated in this study. The maximum angle of COM-COP and the corresponding envelope areas were recorded in 4 standing posture: natural standing, close eyes standing, single leg standing and single leg standing with eyes closed. Results There was no significant difference in the maximum angle of COM-COP among 3 groups in 3 states (nature standing, close eyes standing, single leg standing with eyes closed) (P>0.05), but there was significant difference in the state of single leg standing (P<0.05) between the young and the old, and the middle-aged and the old. Conclusion The maximum angle of COM-COP in the state of single leg standing can sensitively detect the deterioration of stability of older people. It may be a new index of static balance in clinic.

The optimum flow shear stress and the mass transport benefiting for construction of the tissue-engineered bone combining computational fluid dynamics / 中华骨科杂志

Objective To explore the optimum flow shear stress and mass transport for the construction of tissue-engineered bone.Methods The β-tricalcium phosphate (β-TCP) scaffolds seeded with human bone marrow-derived mesenchymal stem cells (HBMMSCs) were cultured in perfusion bioreactor.When the same flow rate was applied,the flow shear stress was separately 1×,2× and 3×.When the same flow shear stress was applied,the flow rates were separately 3 ml/min,6 ml/min and 9 ml/min.Cell proliferation was measured by MTT method.The construction of tissue-engineered bone was evaluated by measuring alkaline phosphatase (AKP) activity,secretion of osteopontin (OP) and osteocalcin (OC),and the mineralization of extracellular matrix (ECM).The flow shear stress and the mass transport were obtained using computational fluid dynamics.Results When the flow rate was same,the most cell proliferation was found in 2× group.The AKP activity and secretion of OC was higher in 2× and 3× groups than in those in 1× group.After 28days,the highest amount of mineralization of ECM was found in 3× group.When the flow shear stress was same,the AKP activity was highest in 6 ml/min group.After 28 days,secretion of OC and formation of mineralized ECM was highest in 3 ml/min group.When the flow rate was same,the flow shear stress was separately 0.004-0.007 Pa,0.009-0.013 Pa and 0.013-0.018 Pa.When the flow shear stress was same,the flow rate was separately 0.267-0.384 mm/s,0.521-0.765 mm/s and 0.765-1.177 mm/s.Conclusion When the tissue-engineered bone was constructed,0.013-0.018 Pa flow shear stress and 0.267-0.384 mm/s mass transport velocity could improve the construction of the tissue-engineered bone in vitro.

Proximal femoral nail antirotation for treatment of intertrochanteric fractures: an analysis of 112 patients / 中华创伤杂志

Objective To investigate the clinical value of proximal femoral nail antirotation ( PFNA) in treatment of intertrochanteric fractures.Methods From April 2007 to July 2009,112 patients with intertrochanteric fractures were treated by using PFNA.There were 34 males and 78 females,at mean age of 76 years.Of all,80 patients were with type 31-A2 fracture and 32 with type 31-A3 fractures according to AO classification.According to Singh index classification,there were 4 patients at grade Ⅰ,21 at grade Ⅱ,70 at grade Ⅲ and 15 at grade Ⅳ.The fracture was caused by low-energy injury in 97 patients and by high-energy injury in 15.The Salvati-Wilson score was used to evaluate the hip function postoperatively.Results Ninety patients received 12-24 months follow-up (average 18.6 months).The Salvati-Wilson score was (29.98 ± 5.18 ) points.The result was excellent in 41 patients,good in 40,fair in 6 and poor in 3,with excellenct rate of 90％.The introduction of the nail in operation was difficult in 22 patients,of which 3 patients suffered femoral cortex rupture.Displacement or separation of the fracture segments occurred in 34 patients and distal locking difficulty in nine during the screw blade tapping process.Local complications included hip pain in 21 patients,thigh pain in 4,apparent coxa vara in 2 and delayed healing in 7.There were no cutting-out or femoral shaft fractures no matter what type of Singh index was.The systemic complications included cardiovascular and cerebrovascular disease in one patient,pulmonary infection in four,deep vein embolism in one and perineum congestion or swelling in seventeen.Conclusion PFNA is effective in treating intertrochanteric fractures especially osteoporotic fractures,but delayed healing of the fractures and the mismatch between the intramedullary nail and the proximal femoral morphology remain to be addressed.

Effects of alendronate on adipogenic differentiation of bone marrow stromal cells derived from ovariectomized rats / 中华创伤杂志

Objective To explore the effects of alendronate on adipogenic differentiation of bone marrow stremal cells (BMSCs) and the role of mitogen-activated protein kinases (MAPK) signal pathway in this process. Methods BMSCs were derived from 9-month-old ovariectomized SD rats and exposed to 0.01, 0.1, 1, 10 μmol/L of alendronate for 2 weeks. The number of BMSCs was counted under light microscope after oil red O staining. The expression of peroxisome proliferators activated receptor-γ, 2 (PPAR-γ2) was measured by RT-PCR. The effect of alendronate on MAPK signal pathway was detected by Western blot. Results After two weeks of induction of BMSCs by alendronate, BMSCs with positive oil red O staining significantly decreased as the increase of the concentration of alendronate (P <0.01), so did the expression of PPAR-γ2. The expression level of PPAR 2 increased when exposing BMSCs to ERK1/2 or JNK specific inhibitors, PD98059 and SP600125 for two weeks. However, the expression level of PPAR 2 decreased when exposing BMSCs to SB203580 (an inhibitor of p38) for two weeks. Condusion Alendronate can inhibit adipogenic differentiation of BMSCs derived from ovariectomized rats in a doso-dependent manner by activating ERK1/2 and JNK rather than p38.

Physicians' Attending May Improve Compliance with Community Exercise Therapy in Knee Osteoarthritis Patients / 中国康复理论与实践

@#Objective To investigate if the physician's attending could improve the compliance of knee osteoarthritis patients with community exercise therapy.Methods The Questionnaire of Community Rehabilitation of Musculoskeletal Disorder was developed.The knee osteoarthritis patients with or without physicians' attending were surveyed anonymously 3 month after exercise.Results The incidence of compliance in exercise was 87.65% in patients with the physicians' attending,and 70.37% without attending(P<0.05).Conclusion The physicians' attending may improve the compliance of knee osteoarthritis patients in community exercise therapy.

Micro-particles of bioceramics could cause cell and tissue damage / 生物医学工程学杂志

We conducted studies to confirm the hypothesis that the cellular damage occurring around implanted biphasic bioceramics could be related to a micro-particles release because of an insufficient sintering. An in vitro cytotoxicity study was performed on four biphasic ceramic (BCP) samples. Without the treatment of extraction medium, a cytotoxicity was observed, although after centrifugation this cytotoxicity disappeared in all samples. (2) Micro-particles of HA, beta-TCP and 40%beta-TCP/60%HA mixture were used for a cell inhibition study. A decrease of cell viability was observed with the increase in particles concentration. At 10000 particles/ cell, the viability and proliferation were completely inhibited. (3) HA, beta-TCP and BCP ceramic granules were implanted in rabbit femoral cavities for 12 weeks. No degradation of HA granules was observed. The degradation was higher for beta-TCP (40%) than for BCP (5%). On the other hand, new bone formation was significantly higher for beta-TCP (21%) and HA (18%) than for BCP (12%). Much more micro-particles were formed around BCP granules than around beta-TCP, and were phagocytosed by macrophages. The release of ceramic micro-particles could be related to the sintering process. BCP ceramics have to be sintered at only 1160 degrees C. Consequently, HA microparticles of BCP ceramic are incompletely sintered and easily released after immersion or implantation. The microparticles could be at the origin of local inflammation and cell damage and could perhaps modify osteogenesis. Particular attention must be paid to this problem with regard to BCP ceramics because of the sintering difficulties of this bioceramic.

Computer-aided measurement of medullary cavity of proximal femur / 中国组织工程研究

BACKGROUND: Clinical studies demonstrate that the durable stability of the prosthesis depends on a close geometric fit between the prosthesis and femoral medullary cavity.OBJECTIVE: To study the law of the parameters of medullary canal section shape in proximal femur DESIGN: Repeated measurement observation.SETTING: Department of Orthopaedics, Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University MATERIALS: Ten femoral samples without any damage was obtained from corpse in the Staff Room of Anatomy of the Shanghai Second Medical University METHODS: The experiment was carried out in the Department of Or thopaedics, Ninth People's Hospital between January 2000 and March 2000. Section morphology of medullary cavity of proximal femur was dealt with image-processing, and conus curve fitted parameter mathematical method was proposed; and at the same time, section of medullary cavity of proximal femur of 10 patients was measured manually.MAIN OUTCOME MEASURES: Computer-aided method and manual method were applied to measure the coordination at the end of extrude and the coordinate of link joint RESULTS: 10 femoral samples entered the stage of result analysis. Com puter was used to measure the coordination of the end of extrude of the section medullary cavity of proximal femur (X,Y) and the coordination of the connection point (X,Y).There was no significant difference of the measuring results between computer-aided method and manual CONCLUSION: Computer-aided imaging-processing method not only reduces the error but also can be completed by computer automatically in measuring section morphology of medually cavity in proximal femur. It is suitable for a variety of morphology measurement.