Infectious-purulent complications in lower extremity injuries represent an extremely complex and priority problem in modern traumatology and orthopedics, including military field medicine. According to current epidemiological data, postoperative infections in elective surgical interventions are diagnosed on average in 6.5% of patients nationwide, with half of all postoperative fatalities directly associated with purulent-septic processes [1]. In open injuries of bones and soft tissues, the risk of infection increases sharply, ranging from 50 to 65% in gunshot and blast wounds of the extremities [2].

Pathology of the lower extremities accounts for a substantial proportion of the overall injury burden. Open fractures are characterized by prolonged bone fragment union times and high rates of infectious complications, leading to the need for reoperations and reduced functional treatment efficacy. International multicenter studies demonstrate that infection after hospital discharge develops in 3.4% of patients with leg fractures, and the open nature of the injury doubles this probability [3, 4].

The predominant pathogens most commonly are Staphylococcus aureus (including methicillin-resistant strains), various groups of streptococci, gram-negative microorganisms (Escherichia coli, Enterobacteriaceae, Acinetobacter baumannii), and anaerobes [5]. Increasing antimicrobial resistance causes serious concern and contributes to rising complication rates and mortality. Contemporary studies report purulent complications in transosseous osteosynthesis in 44.5% of cases, while osteomyelitis develops in 5 to 22.4% of operated patients with open fractures. Chronic traumatic osteomyelitis develops as a consequence of open fractures in 65% of patients (including up to 43% from gunshot wounds) and following closed trauma treatment in 28% of cases [6].

The Yaroslavl region, being an industrial region with a high proportion of road traffic and occupational injuries, demonstrates a specific profile of trauma admissions. The lack of systematic regional data on the prevalence, structure, and clinical presentation of purulent complications hinders the development of targeted prevention programs and the optimization of diagnostic and treatment algorithms. Analysis of the prevalence and dynamics of purulent complications in the region will not only allow assessment of the effectiveness of preventive and therapeutic measures but also facilitate resource planning for medical institutions and optimization of traumatology and surgical services.

To study the epidemiological patterns and clinical features of purulent complications in patients with lower limb injuries who were treated in medical organizations in the city of Yaroslavl and the Yaroslavl Region.

Study organization. A comprehensive epidemiological analysis was conducted of data on the prevalence of purulent complications associated with lower extremity injuries among patients receiving inpatient treatment in traumatology, orthopedics, and surgical departments of medical organizations in Yaroslavl Oblast. The study was conducted within the framework of a dissertation on "Treatment of purulent complications and prediction of their outcomes in patients with trauma of the mid-distal lower extremity" (excerpt from Protocol No. 11 of the Academic Council of Yaroslavl State Medical University dated 26.06.2024, state registration number: 124071000009-0). The work was approved by the Ethics Committee (excerpt from Protocol No. 68 of the meeting of the Ethics Committee of Yaroslavl State Medical University dated June 14, 2024).

Data source. Statistical data on the prevalence of injuries, trauma sequelae, and complications were obtained from the Ministry of Health of the Yaroslavl Region (response to a data request No. ИХ.19-3350/2025 dated 28.05.2025) for 2016-2025. Clinical data were collected at the N.V. Solovyov Clinical Hospital of Emergency Medical Care (GAUZ YO "KBSMP"). The collected material is presented as a registered database No. 2025626215 dated 17.12.2025 [7].

Study objectives:

The assessment of the dynamics of purulent complication cases over the specified period demonstrates some heterogeneity across years (see Table 1).

Table 1. Dynamics of cases of purulent complications after lower extremity injuries in the Yaroslavl region for 2016-2025.

YearNumber of casesAbsolute increase (to previous year)Growth rate (%)Rate of increase (%)2016822-100.0-2017594-22872.3-27.72018388-20665.3-34.72019904+516232.9+132.92020747-15782.6-17.42021906+159121.3+21.32022561-34561.9-38.12023658+97117.3+17.32024526-13279.9-20.12025172-35432.7-67.3

The mean value was 627.8 cases per year, median — 627.5, standard deviation 241.3 cases, and the coefficient of variation equaled 38.4%, indicating high instability in the indicators. Trend analysis confirms a pronounced downward tendency in recent years: the linear regression coefficient shows an average annual decrease of 62.4 cases (R²=0.42), evidencing a moderately positive dynamic. Particularly noteworthy is the sharp drop in 2025 to a historical minimum, which constitutes only 20.9% of the 2016 level and 19.0% of the 2021 peak (see Fig. 1).

Fig. 1. Graphical distribution based on the results of the time trend analysis

As shown in the figure, three characteristic incidence peaks were observed over the ten-year period: in 2016 (822 cases) as an initial high level, likely due to insufficient effectiveness of preventive measures; then in 2019 (904 cases) with a sharp increase of 132.9% compared to 2018, which may have been caused by changes in complication recording methodology or an unfavorable epidemiological situation; and in 2021 (906 cases) — the absolute maximum for the period, likely associated with the consequences of the COVID-19 pandemic and the redistribution of medical resources. After 2021, a sustained downward trend in case numbers formed, despite a small fluctuation in 2023.

At the next stage, an assessment of complications in the overall structure of traumatic pathology was performed by comparing the identified cases of purulent complications after lower extremity injuries over the study period with overall injury data and nosology accounting (see Table 2).

Table 2. Relative frequencies of complications (% of total injuries) for 2016-2025.

YearTotal injuriesM00; M86 (%)T80-T88 (%)T90-T98 (%)Total complications (%)2016305242.69%1.05%0.07%3.81%2017285232.08%1.20%1.69%4.97%2018309171.25%0.31%1.05%2.61%2019308452.93%0.60%1.29%4.82%2020273042.74%0.95%0.85%4.54%2021281683.22%1.25%2.16%6.63%2022285331.97%0.78%2.82%5.57%2023292242.25%3.19%4.78%10.22%2024302501.74%1.55%2.50%5.79%2025300890.57%1.46%3.01%5.04%

The mean number of infectious complications over 10 years was 627.8 cases per year, with an average frequency of 2.14% of all recorded injuries. Summary statistical indicators for significant nosologies are presented in Table 3.

Table 3. Summary statistical indicators for 2016-2025.

CategoryTotal cases (2016-2025)Annual meanProportion of total injuriesMinimum frequencyMaximum frequencyInjuries S80-S89119,79611,979.641.1%10,870 (2020)12,753 (2018)Injuries S90-S99171,58117,158.158.9%16,434 (2020)18,336 (2019)Total injuries294,37729,437.7100.0%27,304 (2020)30,917 (2018)M00; M866,278627.82.14%0.57% (2025)3.22% (2021)T80-T883,614361.41.23%0.31% (2018)3.19% (2023)T90-T985,928592.82.02%0.07% (2016)4.78% (2023)Total complications15,8201,582.05.39%2.61% (2018)10.22% (2023)

Over the ten-year period, 294,377 cases of lower extremity injuries were registered in the Yaroslavl region, averaging approximately 29.4 thousand cases per year. A predominance of ankle and foot injuries (58.9%) was noted against 41.1% of knee and leg injuries of all injuries. This ratio corresponds to international epidemiological data, where injuries to the distal lower extremities predominate over proximal ones [8, 9].

The obtained data on the dynamics of post-traumatic infectious complications over the ten-year period demonstrate an average frequency of 2.14%, but with a pronounced downward trend from the peak in 2021 (3.22%) to the minimum in 2025 (0.57%). This decrease may be attributed to the improvement of antiseptic protocols, the introduction of prophylactic antibiotic therapy, and improved conditions of medical care; on the other hand, it may be associated with discrepancies in the recording system due to the COVID-19 pandemic [10], which underscores their role as a breakthrough achievement in prevention. The abnormal increase in complications after medical interventions in 2023 by 2% may also be related to registration problems and differentiation of the identified complication [11]. In some countries, artificial intelligence is used for more accurate registration of a given complication case, which automatically analyzes a specific patient in existing databases based on earlier hospitalizations and accordingly determines the current disease status, namely a newly identified complication or its recurrence [12].

The opposite situation is observed in the accounting of trauma sequelae, which can also serve as initial manifestations of subsequent infectious complications, where an extreme increase is noted from 0.07% (2016) to 4.78% in 2023, with sustained growth maintained over the last three years. This trend may indicate both improved registration of long-term effects, an increase in severe injuries and accumulation of chronic pathology, and the desire of medical organizations to "smooth out" statistics on infectious complications [13, 14].

In Yaroslavl and the region, a high epidemiological burden of lower extremity injuries persists, with a predominance of ankle and foot injuries. The overall complication rate reaches 5.39% with an upward trend. The most dynamic increase is observed in the "trauma sequelae" category, emphasizing the need for enhanced rehabilitation care in traumatology. Low and stable rates of infectious complications confirm the effectiveness of prevention, but at the same time, there is a lack of reliable data on the prevalence of all infectious complications and their recurrences after lower extremity injury treatment, such as abscess, suppuration in the osteosynthesis zone, ligature fistulas, postoperative wound necrosis, and migration of metal constructs with skin perforation. Additionally, some complications are lost in purely surgical statistics or are modified at the moment of registration up to a new nosology, for example, post-traumatic osteomyelitis of the foot bones may be registered as "diabetic foot." It is precisely for these reasons that, on the one hand, a multicenter study is required, which will allow seeing the true picture of the problem of purulent complications and enable the necessary measures to improve the quality of medical care, and on the other hand, tracking the maximum possible number of patients from the moment of injury to the completion of treatment of the existing complication or its recurrence within one year of observation.