Doo-Hyung Lee

Objective: This study aimed to investigate the incidence and potential predictors of delayed displacement in minimally displaced clavicle fractures associated with polytrauma. It was hypothesized that polytrauma-related factors may reduce the risk of delayed displacement by limiting early patient mobilization. Methods: Between 2018 and 2021, a cohort study was conducted on 79 patients with minimally displaced clavicle fractures who had an injury severity score (ISS) of 16 or greater and were initially treated conservatively. The patients underwent regular radiographic examinations and those who exhibited displacement of more than 100% during follow-up were classified as having delayed displacement and subsequently underwent surgical intervention. Univariate and multivariate logistic regression analyses were used for statistical analysis to evaluate the risk factors for delayed displacement. The factors included polytrauma-related factors, such as the ISS, accompanying upper extremity injury, scapular fracture, rib fracture, level of consciousness, traumatic central nervous system injury, intensive care unit admission, use of a ventilator, duration of intubation, and fracture-specific factors, which were the location of the fracture and the presence of comminution. Results: Overall, 31 patients (39.2%) had delayed displacement. The univariate and multivariate logistic regression analyses showed that the statistically significant risk factors for delayed displacement of clavicle fractures were the presence of comminuted fractures and fractures located in the middle third of the clavicle shaft (odds ratio = 5.954 and 4.423, respectively; P = .003 and .018, respectively), while polytrauma-related factors were not associated. Conclusion: Polytrauma-related factors were not significantly associated with delayed displacement in minimally displaced clavicle fractures accompanied by polytrauma. Instead, fracture-specific characteristics, such as midshaft location and comminution, emerged as important predictors of delayed displacement, even when the initial displacement was minimal. These findings highlight the need for regular radiographic monitoring for at least 5 weeks in patients with polytrauma, particularly when such fracture characteristics are present. Cite this article as: Lee D, Han K, Park YU, Cho W, Koh J, Choi W. Delayed displacement of minimally displaced clavicle fractures in polytrauma patients: a retrospective cohort study. Acta Orthop Traumatol Turc., 2026; 60(3), 0511, doi: 10.5152/j.aott.2026.25511.

This study investigates the reintroduction and ecological adaptation of the endangered dung beetle, Gymnopleurus mopsus, in South Korea, a region from which it has been absent since the 1970s. To facilitate this, we imported genetically identical populations of G. mopsus from Mongolia and embarked on a comprehensive restoration research project. A key focus of this endeavor was to evaluate the adaptability of these beetles to the local environment, an essential aspect of successful reintegration of species from foreign ecosystems. Under meticulously controlled field cage conditions, we conducted an in-depth monitoring of the life history traits of G. mopsus. This monitoring revealed that the adult beetles, which entered hibernation in September 2019, began emerging in stages from late April to May 2020. Following hibernation, we observed that the adults engaged in reproductive activities from late-May until early-August, with the emergence of the first-generation (F1) adults occurring from late-July to mid-September. This led to a notable tripling in population size, increasing from 34 to 109 individuals. The successful survival and reproductive behaviors of these Mongolian dung beetles in the climatic conditions of Korea suggest a promising potential for their adaptation when reintroduced into native habitats. We are now directing our efforts towards long-term monitoring, focusing on the survival and reproductive efficacy of these new generations, to further validate the success of this ecological restoration project.

This study investigates the reintroduction and ecological adaptation of the endangered dung beetle, Gymnopleurus mopsus, in South Korea, a region from which it has been absent since the 1970s. To facilitate this, we imported genetically identical populations of G. mopsus from Mongolia and embarked on a comprehensive restoration research project. A key focus of this endeavor was to evaluate the adaptability of these beetles to the local environment, an essential aspect of successful reintegration of species from foreign ecosystems. Under meticulously controlled field cage conditions, we conducted an in-depth monitoring of the life history traits of G. mopsus. This monitoring revealed that the adult beetles, which entered hibernation in September 2019, began emerging in stages from late April to May 2020. Following hibernation, we observed that the adults engaged in reproductive activities from late May until early August, with the emergence of the first-generation (F1) adults occurring from late July to mid-September. This led to a notable tripling in population size, increasing from 34 to 109 individuals. The successful survival and reproductive behaviors of these Mongolian dung beetles in the climatic conditions of Korea suggest a promising potential for their adaptation when reintroduced into native habitats. We are now directing our efforts towards long-term monitoring, focusing on the survival and reproductive efficacy of these new generations, to further validate the success of this ecological restoration project.

This study aimed to investigate the effects of symbiosis on the life history of host insects and address their implications at the host population level. We evaluated the effects of symbiotic bacteria Caballeronia insecticola on its host Riptortus pedestris (Fabricus) (Hemiptera: Alydidae) from cohorts for nymphal development, adult survivorship, and female reproduction. Then, life table parameters were compared between symbiotic and apo-symbiotic groups, and the effects of symbiosis on the abundance of R. pedestris were simulated for varying proportions of symbiotic individuals in host populations. We found that symbiosis significantly accelerated the nymphal development and reproductive maturation of females. However, symbiosis incurred survival cost on adult females, reducing their longevity by 28.6%. Nonetheless, symbiotic females laid significantly greater numbers of eggs than the apo-symbiotic during early adult ages. This early reproductive investment negated the adverse effect of their reduced longevity, resulting in the mean lifetime fecundity to not significantly differ between the 2 groups. Indeed, total cohort fecundity of the symbiotic group was 1.3-fold greater than that of the apo-symbiotic group. Life table analysis demonstrated shorter generation time and greater population growth rate in the symbiotic population. Finally, the simulation model results indicate that an increase in the proportion of symbiotic R. pedestris favored the population growth, increasing the population size by 1.9 times for every 25% increase in the proportion of symbiotic individuals. Our study demonstrates that symbiont-mediated changes in the life history parameters of host individuals favor the host population growth, despite substantial reduction in the female longevity.

Tracking of soil-dwelling insects poses greater challenges compared to aboveground-dwelling animals in terrestrial systems. A metal detector system consisting of a commercially available detector and aluminum tags was developed for detecting dung beetle, Copris ochus Motschulsky (Coleoptera: Scarabaeidae). First, detection efficacy of the system was evaluated by varying volumes of aluminum tags attached on a plastic model of the insect and also by varying angles. Then, detection efficacy was evaluated by varying depths of aluminum-tagged models under soil in 2 vegetation types. Finally, the effects of tag attachment on C. ochus adults were assessed for survivorship, burrowing depth, and horizontal movement. Generally, an increase in tag volume resulted in greater detection distance in semi-field conditions. Maximum detection distance of aluminum tag increased up to 17 cm below soil surface as the tag size (0.5 × 1.0 cm [width × length]) and thickness (16 layers) were maximized, resulting in a tag weight of 31.4 mg, comprising ca. 9% of average weight of C. ochus adult. Furthermore, the detection efficacy did not vary among angles except for 90°. In the field, metal detectors successfully detected 5 aluminum-tagged models in 20 × 10 m (W × L) arena within 10 min with detection rates ≥85% for up to depth of 10 cm and 45%–60% at depth of 20 cm. Finally, aluminum tagging did not significantly affect survivorship and behaviors of C. ochus. Our study indicates the potential of metal detector system for tracking C. ochus under soil.

Population dynamics of hard ticks and their harboring rates of fatal severe fever with thrombocytopenia syndrome (SFTS) were monitored from 2021 to 2022 in Gyeonggi-do, South Korea. Hard ticks were surveyed monthly using CO₂-bait traps in four vegetation types, including grassland, grave, mountain trail, and shrub. From the 2-year monitoring, totals of 5,737 and 14,298 hard ticks were collected in 2021 and 2022, respectively, all of which belonged to the genus Haemaphysalis. Of these collected ticks, 97.9 and 98.3% of adults and nymphs were identified as Haemaphysalis longicornis. Generally, density peaks of H. longicornis nymphs and adults were observed from April to May and from June to July, respectively. For Haemaphysalis flava, adults showed density peaks in September, whereas no obvious seasonal patterns were observed for nymphs. The density peak of Haemaphysalis larvae was observed in August and September, followed by a density peak of adults. There was a large variation in the number of hard ticks collected among the four vegetation types, yielding no significant difference among them over the 2-year monitoring. Half of the collected ticks from each vegetation type were pooled into groups by species and developmental stage and subjected to analysis of SFTS virus harboring rates, which yielded no SFTS positive pool detected over the 2-year monitoring.