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.

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.

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.

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.

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.

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.

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.

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.