Purpose: There have been over 40 descriptions of the common developmental variants of the accessory ossicles of the feet. Although predominantly asymptomatic, they sometimes may be linked to painful conditions. One of the most common accessory ossicles in the foot is the accessory navicular bone (AN), located on the medial side of the foot. Our research provides a first meta-analysis on this topic that establishes its frequency by contrasting 39 studies from across the globe. Methods: Up to February 2024, PubMed and Embase databases were thoroughly searched for research on the AN. Eligible data regarding AN prevalence was extracted. This study strictly adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 39 studies, 11,015 patients, and 36,837 feet were analyzed in our study. The pooled prevalence estimate (PPE) of AN was found to be 17.5% (95%CI: 11.5–25.7) and 12.6% (95%CI: 10.1–15.5) in patients and feet analyses, respectively. Accessory navicular occurred bilaterally in 50.0% of patients, with similar distribution in gender-based groups (21.1% of males and 22.0% of females were confirmed with AN). Accessory navicular was most prevalent in the East Asian population (38.4%) and least prevalent in North Americans (8.0%). No significant differences in AN prevalence were found when comparing different imaging modalities (X-ray and cadaver dissection). Conclusion: Accessory navicular is a common finding in imaging studies. Its prevalence depends on the population covered by the study but is not affected by the patient’s gender or the imaging modality utilized for AN assessment.

Os trigonum (OT) is one of the most common accessory ossicles in the foot and ankle region. It is believed that OT was first described by Rosenmuller in 1804, but von Bardeleben is the one who coined the nomenclature for this anatomical variation in 1883. The literature indicates that OT is extremely variable in prevalence, with reported rates ranging from 1.7% to 32.5%. In clinical practice, OT is a considerable factor that may predispose patients to posterior ankle impingement syndrome (PAIS). The aim of this study was to provide comprehensive data on the prevalence and anatomical characteristics of OT. We conducted a comprehensive search of the main electronic databases to find the relevant research. Information concerning geographical origin, prevalence, gender distribution, imaging modality, and morphometry of OT was extracted. The PRISMA guidelines were strictly followed throughout the study. The reliability of the included studies was assessed using the AQUA tool. A total of 41 studies (n = 36,612 feet) were included in this meta-analysis. This meta-analysis showed that OT was present in 9.0% (95% CI: 7.4–10.8) of the feet, and was present bilaterally in 32.7% (95% CI: 23.3–43.7) of cases. Regarding the types of imaging modality used in the evaluation of OT by the included studies, prevalence assessed by X-rays was 8.2% (95% CI: 6.8–9.9), MRI was 24.2% (95% CI: 14.6–37.3), CT was 21.0% (95% CI: 12.8–32.5), and cadaveric dissection was 5.0% (95% CI: 3.4–7.4). OT was most commonly found in East Asia (11.0%, 95% CI: 7.1–16.8). Two studies provided enough data to calculate the odds ratio linking PAIS with OT. The analysis showed that patients with PAIS are almost 16 times more likely to have OT compared to those without PAIS (OR = 15.98, 95% CI = 0.255–1002.8). OT is a very common accessory ossicle and is present in nearly one in 10 feet. The highest prevalence is noted in the East Asian population. MRI and CT show the highest prevalence of OT. It is important to keep in mind the possible presence of OT when a patient is diagnosed with PAIS.

Endoprostheses are prone to tribological wear and biological processes that lead to the release of particles, including aluminum nanoparticles (Al NPs). Those particles can diffuse into circulation. However, the toxic effects of NPs on platelets have not been comprehensively analyzed. The aim of our work was to investigate the impact of Al NPs on human platelet function using a novel quartz crystal microbalance with dissipation (QCM-D) methodology. Moreover, a suite of assays, including light transmission aggregometry, flow cytometry, optical microscopy and transmission electron microscopy, were utilized. All Al NPs caused a significant increase in dissipation (D) and frequency (F), indicating platelet aggregation even at the lowest tested concentration (0.5 µg/mL), except for the largest (80 nm) Al NPs. A size-dependent effect on platelet aggregation was observed for the 5–20 nm NPs and the 30–50 nm NPs, with the larger Al NPs causing smaller increases in D and F; however, this was not observed for the 20–30 nm NPs. In conclusion, our study showed that small (5–50 nm) Al NPs caused platelet aggregation, and larger (80 nm) caused a bridging–penetrating effect in entering platelets, resulting in the formation of heterologous platelet–Al NPs structures. Therefore, physicians should consider monitoring NP serum levels and platelet activation indices in patients with orthopedic implants.

Background: The recurrent artery of Heubner (RAH) is typically the largest medial lenticulostriate branch of the anterior cerebral artery (ACA). Neurosurgical procedures such as aneurysm treatment on the anterior part of the circle of Willis can result in damage of the RAH leading to neurological deficits. The aim of this study was to identify the gaps and provide comprehensive data on the prevalence and anatomical characteristics of the RAH with neurosurgical considerations. Methods: The major electronic databases were thoroughly searched to identify the eligible studies. The information concerning study type, geographical origin, prevalence of the RAH, course and origin of the RAH, symmetry of origin and number of RAHs in each hemisphere, and morphometric data were extracted. The PRISMA guidelines were rigorously followed throughout the study. The AQUA tool was used to evaluate the reliability of included studies. Results: A total of 34 studies (n = 3645 hemispheres) were included in the meta-analysis. The analysis revealed that the RAH was present in 97.5% (95%CI: 95.5–98.6) of the hemispheres, originating most frequently from the A2 segment (42.2%, 95%CI: 35.0–49.7) or the ACoA-ACA junction (41.6%, 95%CI: 34.0–49.6), and coursing anteriorly (47.6%, 95%CI: 38.7–56.6) or superiorly (43.9%, 95%CI: 34.4–53.8) in relation to ACA. Almost a quarter of patients had more than one RAH, which was on average 22.82 mm (SD: 1.35, 95%CI: 20.16–25.47; I² = 99.1%, p < 0.01) long and reached 0.76 mm (SD: 0.05, 95%CI: 0.66–0.85; I² = 99.4%, p < 0.01) in diameter. Conclusions: As the RAH is present in the majority of the population, it is important to be aware of the wide variations in its anatomy. This will help to prevent postoperative neurological deficits by avoiding undesirable complications during surgeries that are performed in close proximity to the anterior segment of the circle of Willis.