Articular cartilage (AC) plays an important role in the biomechanics of synovial joints. Its task is to enable smooth movement and transfer of mechanical loads with minimised friction. AC is characterised by unique mechanical properties resulting from its complex structure, in which the dominant components are type II collagen, proteoglycans and water. Healthy articular cartilage shows elasticity in compression, viscoelastic properties, and the ability to relax stresses under the influence of cyclic loads. In response to different loading modes, it shows anisotropic and non-uniform behaviour, which translates into its cushioning and protective function for the subchondral bone. Significant changes occur in the structure and mechanical properties of cartilage with age as a result of mechanical overload or degenerative diseases, such as osteoarthritis. This results in a deterioration of the cushioning and mechanical function, which leads to progressive degradation of joint tissues. Understanding the mechanical properties of AC is crucial for developing effective diagnostic methods. Analysis of changes in mechanical properties contributes to the early detection of pathological changes. The aim of this paper is to review the current state of knowledge regarding the structure and biomechanical properties of articular cartilage, and to analyse conventional and alternative diagnostic methods in the context of their suitability for assessing the state of AC, particularly in the early stages of degenerative processes.

Three-dimensional (3D) printing has gained substantial interest among scientists and surgeons over the past decade due to its broad potential in medical applications. Its clinical utility has been increasingly recognized, demonstrating promising outcomes for patient care. Currently, 3D printing technology enables surgeons to enhance operative precision by facilitating the creation of patient-specific anatomical models, customized implants, biological tissues, and even surgical instruments. This personalization contributes to improved surgical outcomes, reduced operative times, and shorter postoperative recovery periods. Furthermore, 3D printing significantly aids in the customization of prostheses to conform closely to individual anatomical structures. Beyond therapeutic applications, 3D printing serves as a valuable educational tool in medical training. It enhances case-specific visualization, elucidates fracture mechanisms, and provides tangible models for simulation-based practice. Although the use of 3D printing might be seen as useful mostly in orthopedics, it has expanded into multiple medical specialties, including plastic surgery, dentistry, and emergency medicine. Presently, 3D-printed constructs are routinely employed for preoperative planning, prosthetic development, fracture management, and the fabrication of patient-specific surgical tools. Futuristically, the integration of 3D printing into clinical practice is expected to play a pivotal role in the advancement of personalized medicine, offering substantial benefits for both healthcare providers and patients.

Proper joint function has a significant impact on people’s quality of life. Joints are the point of connection between two or more bones and consist of at least three elements: joint surfaces, the joint capsule, and the joint cavity. Joint diseases are a serious social problem. Risk factors for the development of these diseases include overweight and obesity, gender, and intestinal microbiome disorders. Another factor that is considered to influence joint diseases is trace elements. Under normal conditions, elements such as iron (Fe), copper (Cu), cobalt (Co), iodine (I), manganese (Mn), zinc (Zn), silver (Ag), cadmium (Cd), mercury (Hg), lead (Pb), nickel (Ni) selenium (Se), boron (B), and silicon (Si) are part of enzymes involved in reactions that determine the proper functioning of cells, regulate redox metabolism, and determine the maturation of cells that build joint components. However, when the normal concentration of the above-mentioned elements is disturbed and toxic elements are present, dangerous joint diseases can develop. In this article, we focus on the role of trace elements in joint function. We describe the molecular mechanisms that explain their interaction with chondrocytes, osteocytes, osteoblasts, osteoclasts, and synoviocytes, as well as their proliferation, apoptosis, and extracellular matrix synthesis. We also focus on the role of these trace elements in the pathogenesis of joint diseases: rheumatoid arthritis (RA), osteoarthritis (OA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), and systemic lupus erythematosus (SLE). We describe the roles of increased or decreased concentrations of individual elements in the pathogenesis and development of joint diseases and their impact on inflammation and disease progression, referring to molecular mechanisms. We also discuss their potential application in the treatment of joint diseases.

Background: Free fatal falls (FFF) are a frequent occurrence in forensic medicine. Many variables, such as the victim’s sex, BMI, intoxication, height of the fall, and mental illness, can influence injury patterns. Previous studies identified fracture patterns and frequencies mostly with general anatomical detail, focusing on broad areas. As specific fractures might be roots for new statistical connections, this leaves a gap in our understanding. Using postmortem computed tomography, we aim to establish fracture frequencies and identify possible new statistical connections. Methods: In total, we retrospectively analyzed seventy-nine cases of confirmed deaths due to falls using the database of the Department and Institute of Forensic Medicine in Lublin. Our inclusion criteria were death due to free fall onto hard, non-deformable surfaces. We excluded cases of ground-level falls. All victims must have undergone postmortem computed tomography. Furthermore, each analyzed case documented individual intrinsic variables (sex, age, body mass, height, pre-existing mental conditions, and drug or alcohol use) and extrinsic variables (fall height, landing surface, time between the fall and death, and known cause of the fall). Results: Injuries in free fatal falls tend to focus on the axial skeleton. Suicides experience more severe, bilateral fractures, often involving the pelvis and limbs, while accidents tend to have unilateral injuries with rare limb involvement. We established new correlations with the height of the fall for the maxilla, mandible, anterior and posterior regions of the occipital bone, and the temporal bone. Moreover, our research confirmed previously noted correlations between the height of the fall and fractures of the limbs (and their individual bones), the lumbar vertebrae, and the chest. Conclusions: Our findings highlight that free fatal falls are characterized by distinct skeletal injury patterns that differ between accidents and suicides, with bilateral pelvic and limb fractures being particularly indicative of intentional falls. The integration of PMCT with autopsy improves the detection of these patterns. It provides valuable diagnostic and medico-legal insights, supporting a more precise determination of the cause and manner of death.