We used a three-dimensional rigid body spring model (RBSM) to compare the contact force distributions on the acetabular surface of the infant hip joint that are produced by three orthopedic treatments for developmental dysplasia of the hip (DDH). We analyzed treatments using a Pavlik harness, a generic rigid splint, and a spica cast. The joint geometry was modeled from tomography images of a 1-year-old female. The articular cartilage was modeled as linear springs connecting the surfaces of the acetabulum and the femoral head, whereas the femur and the hip bone were considered as rigid bodies. The hip muscles were modeled as tensile-only preloaded springs. The treatments with the Pavlik harness and the generic rigid splint were modeled for an infant in supine position with a hip flexion angle of 90 deg. Also, since rigid splints are often recommended when children are initiating their gait phase, we modeled the treatment with the infant in standing position. For the spica cast, we only considered the infant in standing position with a flexion angle of 0 deg, and the fixation bar at two heights: at the ankle and at the knee. In order to analyze the effect of the hip abduction angle over the contact force distribution, different abduction angles were used for all the treatments modeled. We have found that the treatments with the infant in supine position, with a flexion angle of 90 deg and abduction angles between 60 deg and 80 deg, produce a more homogenous contact force distribution compared to those obtained for the treatments with the infant in standing position.

In-silico models applied to bone remodeling are widely used to investigate bone mechanics, bone diseases, bone-implant interactions, and also the effect of treatments of bone pathologies. This article proposes a new methodology to solve the bone remodeling problem using one-dimensional (1D) elements to discretize trabecular structures more efficiently for 2D and 3D domains. An Euler integration scheme is coupled with the momentum equations to obtain the evolution of material density at each step. For the simulations, the equations were solved by using the finite element method, and two benchmark tests were solved varying mesh parameters. Proximal femur and calcaneus bone were selected as study cases given the vast research available on the topology of these bones, and compared with the anatomical features of trabecular bone reported in the literature. The presented methodology has proven to be efficient in optimizing topologies of lattice structures; It can predict the trend of formation patterns of the main trabecular groups from two different cancellous bones (femur and calcaneus) using domains set up by discrete elements as a starting point. Preliminary results confirm that the proposed approach is suitable and useful in bone remodeling problems leading to a considerable computational cost reduction. Characteristics similar to those encountered in topological optimization algorithms were identified in the benchmark tests as well, showing the viability of the proposed approach in other applications such as bio-inspired design.

Leg kicks are fundamental techniques in combat sports based on a proximal-distal sequence involving several factors that can affect mechanical efficiency and injury risk. However, there is a lack of comprehensive reviews that integrate biomechanical and epidemiological evidence on injuries in an interdisciplinary context. Background/Objectives: This narrative review synthesizes current evidence to explore the relationship between mechanical efficiency and injury risk in kick-based combat sports. Methods: The search was conducted across Web of Science and Scopus (January 2000–March 2025) or studies investigating the biomechanics and injury risk factors associated with leg kicks in Taekwondo, Karate, Muay Thai, Kickboxing, and MMA. Results: Analysis of 23 studies identified three primary technical determinants of efficiency: stance mechanics, hip rotation, and striking-surface selection. High-impact force is consistently associated with a pivoted support leg stance and proximal-to-distal coordination. However, these same mechanics create specific “load concentrations” that align with documented injury profiles: pivoted stances increase rotational stress on the support leg knee (ACL/meniscal strain), while striking-surface choice (shin vs. instep) dictates the trade-off between tibial stress and metatarsal/ankle trauma. Conclusions: This review proposes an Integrated mechanical efficiency–injury model that suggests that performance optimization and injury awareness are two sides of the same biomechanical process. Future research should fill the gaps relating to the subject’s age and gender parity, as well as direct comparisons between different sports.