Introduction and Objective. Virtual Surgical Planning (VSP) is becoming an increasingly important means of improving skills acquisition, optimizing clinical outcomes, and promoting patient safety in orthopedics and traumatology. Pediatric Orthopedics (PO) often deals with the surgical treatment of congenital or acquired limbs and spine deformities during infancy. The objective is to restore function, improve aesthetics, and ensure proper residual growth of limbs and spine, using osteotomies, bone grafts, age-specific or custom-made hardware and implants. Materials and Methods. Three-dimensional (3D) digital models were generated from Computed Tomography (CT) scans, using free open-source software, and the surgery was planned and simulated starting from the 3D digital model. 3D printed sterilizable models were fabricated using a low-cost 3D printer, and animations of the operation were generated with the aim to accurately explain the operation to parents. All procedures were successfully planned using our VSP method and the 3D printed models were used during the operation, improving the understanding of the severely abnormal bony anatomy. Results. The surgery was precisely reproduced according to VSP and the deformities were successfully corrected in eight cases (3 genu varum in Blount disease, 2 coxa vara in pseudo achondroplasia, 1 SCFE, 1 missed Monteggia lesion and 1 post-traumatic forearm malunion deformity). In one case, a focal fibrocartilaginous dysplasia, the intraoperative intentional undersizing of the bone osteotomy produced an incomplete correction of a congenital forearm deformity. Conclusions. Our study describes the application of a safe, effective, user-friendly, VSP process in PO surgery. We are convinced that our study will stimulate the widespread adoption of this technological innovation in routine clinical practice for the treatment of rare congenital and post-traumatic limb deformities during childhood

Many studies describe the use of the Ilizarov ring fixator for lower limb lengthening and for the management of the 3-dimensional lower limb deformities in achondroplasia, and most confirm the efficacy of this technique. However, long term follow up of these achondroplastic patients is lacking. Most studies have focused on magnitude of lengthening, treatment time required and complications, but no study has analyzed the long term postoperative condition of these patients using an objective, functional method such as gait analysis. Nineteen (19) achondroplastic patients, 12 males and 7 females, aged 19–38 years (mean 27.3 y) who have undergone tibia and femur lengthening, using the Ilizarov method, at the age of 9–19 years (mean 12.6 y), were evaluated 5–19 years (mean 10.1 y) after their last surgery, using 3-dimensional gait analysis. Nineteen (19) normal, height-matched subjects were used as controls. The VICON Nexus 8 Camera System was used to accurately measure spatiotemporal characteristics (walking velocity, stride length, step length, cadence) and kinematics (range of motion) of lower limb joints. Statistical comparison of deformity parameters between achondroplastic patients and normal population was done using the student t- test. A level of p<0.05 was considered statistically significant. Walking velocity, step length and stride length were statistically significantly decreased (p<0.05) in achondroplastic patients compared to normal population values. The achondroplastic group presented with excessive anterior pelvic tilt (mean 21.9. o. ± 7.3), excessive pelvic rotation (range 28.7. o. ±7.8), decreased hip extension (mean 1.8. o. ±10.1) and decreased plantar flexion (mean 17.1. o. ±5.1) when compared to normal controls. There was no statistically significant difference in the knee kinematics between the operated achondroplastic patients and normal controls. The achondroplastic patients present decreased values in their spatiotemporal characteristics compared to the normal subjects because, despite the height gain, their lower limbs remain shorter. Their excessive anterior pelvic tilt is attributed to their lordosis. Their excessive forward pelvic rotation is an attempt to increase stride and step length. The decreased hip extension is due to their anterior pelvic tilt. The correction of these patients genu varum restored knee kinematics to normal. In order to address the hip and pelvis deformities a proximal femoral osteotomy should be considered. The Ilizarov method provides functional height gain and substantially corrects the three-dimensional lower limb deformities of achondroplastic patients especially around the knee joint but more planning needs to be implemented when the system is applied to correct the disease specific deformities of the hip and pelvis. Gait analysis is an objective tool that can be used to address these design issues

Summary Statement. Preoperative bone-marrow-derived cell mobilization by G-CSF is a safe orthopaedic procedure and allows circulation in the blood of high numbers of CD34+ve cells, promoting osseointegration of a bone substitute. Introduction. Granulocyte-colony-stimulating-factor(G-CSF) has been used to improve repair processes in different clinical settings for its role in bone-marrow stem cell(CD34+ and CD34-) mobilization. Recent literature suggests that G-CSF may also play a role in skeletal-tissue repair processes. Aim of the study was to verify the feasibility and safety of preoperative bone-marrow cell (BMC) mobilization by G-CSF in orthopaedic patients and to evaluate G-CSF efficacy in accelerating bone regeneration following opening-wedge high tibial valgus osteotomy(HTVO) for genu varum. Patients/Methods. 24 patients were enrolled in a prospective phase II trial. The osteotomy gap was filled by a hydroxyapatite-tricalciumphosphate bone substitute(HATriC). Patients were randomised to receive (GROUP A) or not receive (GROUP B) preoperatively a daily dose of 10µg/kg of G-CSF for three consecutive days, with an additional dose 4 hours before surgery. BMC-mobilization was monitored by white blood cell (WBC)-count, flow-cytometry analysis of circulating CD34+cells and Colony-forming cell assays. Patients were evaluated by: Lysholm and SF-36 scores preoperatively and at 1, 2, 3, 6, and 12 months after surgery;. X-ray evaluation preoperatively and at 1, 2, 3, 6, and 12 months after surgery, in order to compare the percentage of osseointegration of the bone-graft junction using the semi-quantitative score of Dallari[1]. CT-scan of the host bone-substitute interface at 2 months, in order to estimate the quality of the newly formed bone at the bone-graft junction by a quantitative measure of bone density (by Hounsfield unit) at the proximal and distal bone-graft junctions. Results. All patients completed the treatment program without major side effects; G-CSF was well tolerated. BMC-mobilization occurred in all Group A patients, with median peak values of 110/µL (range 29–256) of circulating CD34+ve cells. Circulating clonogenic progenitors paralleled CD34+ve cell levels. A significant improvement in the SF-36-Role-Physical scale and in the Lysholm score was recorded at follow-up in Group A compared to Group B(p<0.05). At the X-ray-evaluation, there was a significant increase in osseointegration at the bone-graft junction in Group A at 1, 2, 3 and 6 months post-surgery compared to Group B(p<0.05). CT-scans of the grafted area at 2 months post-surgery showed no significant difference in the quality of the newly formed bone between the two Groups. Discussion/Conclusions. These results suggest that G-CSF can be safely administered preoperatively in subjects undergoing HTVO. In addition, the clinical, radiographic and CT monitoring indicate that preoperative G-CSF administration promotes bone graft substitute osseointegration. Enhanced osseointegration might be the result of the direct activity of G-CSF on the host bone or a cellular effect mediated by bone marrow-derived progenitors mobilised by G-CSF, or by a combination of all these factors. This study is a proof-of-principle that preoperative G-CSF might be an alternative treatment option to enhance bone regeneration in the field of bone marrow stem cell therapy and reconstructive orthopaedic surgery