Exploring flatfeet morphology in children aged 6-12 years: relationships with body mass and body height through footprints and three-dimensional measurements.

The aim of the study was to determine the relationship between flatfoot morphology and body mass and height in children aged 6-12 years. A total of 6471 Chinese children (mean age 9.0 ± 1.9 years, 41% female) were assessed for foot morphometry, body height, and body mass index. Foot morphology, including foot length, width, girth, arch height, hallux valgus angle, and rearfoot valgus angle, was measured using a 3D laser scanner. Flatfoot evaluations were conducted using the Sztriter-Godunov index (KY) from footprints. All measurements were analyzed by age and sex using the mean values of the left and right sides. Comparisons were performed between flatfoot groups, between body mass index (BMI) groups, and between body height groups. The study revealed a significant decrease in the incidence of bipedal flatfoot with age (p < 0.001), whereas the prevalence of obesity remained consistent (p > 0.05). Bipedal flatfoot was associated with distinct morphological changes, including lower arches, reduced instep height, diminished ankle heights and a greater rearfoot valgus angle (p < 0.05). When comparing the BMI groups, overweight children had larger and thicker feet (p < 0.05), but no differences were found in arch height and ankle height (p > 0.05). When comparing the body height groups, short-statured children had a shorter feet girth, shorter arches, and shorter ankle height (p < 0.05), but no differences were found in the rearfoot valgus angle (p > 0.05). CONCLUSION: The main characteristics of flat feet include lower arches and instep heights and ankle heights but higher rearfoot valgus angles. In general, overweight children's feet do not have the common features of flat feet. In contrast, short children had similar features of flatfoot except for rearfoot valgus. Assessment of posture, such as rearfoot valgus, can be critical in identifying children with flat feet. WHAT IS KNOWN: • The morphology of children's feet is associated with body growth, but the relationship between flatfeet and body mass and height remains controversial. WHAT IS NEW: • Three-dimensional foot measurement shows that body mass is generally not associated with flatfeet, while short children have lower arches but no rearfoot valgus.

Sustentaculum tali in Chinese population: anatomy and clinical significance.

BACKGROUND: Previous studies lacked adequate quantitative data on sustentaculum tali (ST), especially in Chinese population. The aims of this study are to explore the quantitative morphology of ST in dried bone specimens, and to discuss its implications related to ST screw fixation, talar articular facet variation, as well as subtalar coalitions. METHODS: A total of 965 dried intact calcanei from Chinese adult donors were evaluated. All linear parameters were measured by two observers with a digital sliding vernier caliper. RESULTS: Most parts of ST body can accommodate a commonly-used 4-mm-diameter screw, but the minimum height of anterior ST is only 4.02 mm. The shapes of the STs are slightly affected by left-right, subtalar facet, but the subtalar coalition may potentially increase the sizes of STs. The incidence of tarsal coalition is 14.09%. Among the osseous connection, there are 58.8% of type A articular surface and 76.5% of middle and posterior talar facet (MTF and PTF) involvement. ROC curve shows that subtalar coalition will be detected when ST length is greater than 16.815 mm. CONCLUSIONS: Theoretically, all the STs can accommodate 4 mm diameter screw, but a 3.5 mm diameter screw is recommended to be placed in the middle or posterior of the small ST for safety. The shapes of the STs are greatly influenced by the subtalar coalition, while they are less affected by left-right, subtalar facet. The osseous connection is common in type A articular surface and always involved in the MTF and PTF. The cut-off value of the length of STs was confirmed as 16.815 mm for predicting subtalar coalition.

Anatomical parameters of sustentaculum Tali screw placement in the Asian population: A retrospective radio-anatomical study.

Purpose: This study aimed to determine the anatomical parameters of successful Sustentaculum Tali (ST) screw placement in the Asian population. Method: CT scans of unilateral feet of 110 participants were reviewed, retrospectively. The 3 D reconstruction of the calcaneus and morphometric measurements were performed by Mimics Research 19.0 and 3-Matic Research 11.0. Finally, six cadaveric feet were used for verification of the accuracy of the measurements. Results: We discovered a method to help place ST screw successfully: (1) The entry point located at the middle section of the lateral wall of posterior talar articular surface (PTAS), and the perpendicular distance from the entry point to the lateral edge of PTAS (PDEL) was 10.78 mm, (2) Screw was perpendicular to the z-axis, 66.98° to the y-axis (the longitudinal axis of the foot), (3) The length of the ST screw should be approximately 44.74 mm in male and 41.14 mm in female, and (4) The diameter of the ST screw should be approximately 4.0 mm in male and 3.5 mm in female. With this new method, all screws in six cadaveric feet were placed successfully into the middle of ST. Conclusions: In this study, we discovered a general approach to safely place ST screws in the Asian population, which may potentially help surgeons improve their success rate in surgical practice.

Impact of multi-leaf collimator positioning accuracy on quality control of volumetric modulation arc therapy plan for cervical cancer treated with Elekta linear accelerator / 南方医科大学学报

OBJECTIVE@#To investigate the influence of positioning accuracy of the multi-leaf collimators (MLC) on the passing rate of the plan dose verification for volumetric modulation arc therapy (VMAT) of cervical cancer using an Elekta linear accelerator.@*METHODS@#The dose distributions were measured using Sun Nuclear's Mapcheck and Arccheck semiconductors matrix before and after MLC calibration in30 cervical cancer patients undergoing VMAT. Dosimetric comparisons were performed with 2D and 3D gamma passing rates of 3%, 3 mm and 2%, and 2 mm. The 3D gamma distribution was reconstructed with respect to the patient's anatomy using 3DVH software to evaluate the possible influence of MLC positioning accuracy.@*RESULTS@#Before and after MLC calibration, the gamma passing rates of Mapcheck were (88.80±1.81)% and (99.25 ± 0.53)% under 3% and 3 mm standard, respectively, with an average increase of 10.45%. The corresponding gamma passing rates of Arccheck were (87.61±1.98)% and (98.13±0.99)%, respectively, with an average increase of 10.52%. The gamma passing rates of 3DVH were (89.87±2.28)% and (98.3±1.15)%, respectively, with an average increase of 8.43%.@*CONCLUSION@#The MLC positioning accuracy is one of the main factors influencing dosimetric accuracy of VMAT for cervical cancer. The application of Autocal software facilitates MLC calibration and improves the accuracy and safety of VMAT delivery for cervical cancer.