Objective To conduct a comparative analysis of the epidemic characteristics of hemorrhagic fever with renal syndrome (HFRS) in Northeast and Southwest China from 2005 to 2020, and to provide a reference for developing regional prevention and control strategies. Methods Descriptive epidemiological methods were used to analyze the epidemiological characteristics of HFRS outbreaks. The Joinpoint regression model was employed to calculate the annual percentage change (APC) and average annual percentage change (AAPC), thereby analyzing the trends in HFRS incidence. Results From 2005 to 2020, 63 878 HFRS cases were reported in Northeast China (average annual incidence: 3.58/100,000), showing a significant downward trend (AAPC=-13.08%, P<0.05). In Southwest China, 5 313 cases were reported (average annual incidence: 0.168/100 000) with stable overall incidence (AAPC=2.73%, P>0.05) but obvious inter-provincial differences. Northeast had a primary autumn-winter peak (Nov-Dec) and a secondary spring-summer peak (Apr-Jun), while Southwest showed the opposite seasonal pattern. For population distribution, both regions had males (Northeast: 45.01/100 000; Southwest: 1.76/100 000) and farmers aged 20-60 as the main high-risk groups, but differed in the second largest group: household workers/unemployed in the Northeast and students in the Southwest. Incidence presented an inverted ^”U^”-shape with age, peaking in the 40-50 years group. Geographically, high-incidence areas were widely distributed across multiple prefectures (e.g., Shuangyashan) in the Northeast, while in the Southwest, the distribution was highly concentrated, clustered only in a few ethnic minority autonomous prefectures such as Dali and Chuxiong in Yunnan. Conclusion The incidence of HFRS in Northeast China continues to decline, while it remains generally stable but shows localized increases in Southwest China, exhibiting regional differences in seasonal characteristics and geographical distribution. The differences in epidemic patterns across different regions may be related to climate and host species. Differentiated prevention and control strategies should be developed based on the specific epidemic characteristics of each region.

Objective:To evaluate the radiological and functional outcomes of moderate to severe hallux valgus patients with enlarged distal metatarsal articular angle (DMAA) underwent modified Chevron osteotomy.Methods:The clinical data of patients with moderate and severe hallux valgus with increased distal metatarsal joint angle who accepted surgery operation in the Department of Foot and Ankle Surgery of Yantaishan Hospital from October 2020 to December 2022 were retrospectively analyzed. All patients underwent modified Chevron osteotomy. Taking the proximal end of the metatarsal head centre as the osteotomy apex, the vertical arm osteotomy line in the sagittal plane made an angle of ≤80° with the metatarsal stem, the horizontal plane was inclined to the lateral distal end of the metatarsal head by about 10°, and the sagittal plane metatarsal arm osteotomy line made an angle of ≥90° with the vertical arm osteotomy line; at the proximal osteotomy surface, another cuneiform bone with its base on the medial and its apex on the lateral was resected. The deformity correction was insufficient and Akin osteotomy was performed in combination. Weil osteotomy was performed in combination with metatarsalgia. Radiological assessment including the hallux valgus angle (HVA), intermetatarsal angle (IMA), DMAA, the joint congruity angle (JCA), forefoot bone width and soft tissue width was performed preoperatively and at last follow-up postoperatively. American Orthopedic Foot and Ankle Society/hallux metatarsophalangeal-interphalangeal scale (AOFAS/HMIS) was used for clinical and functional evaluation, total score from 0 to 100, with higher scores indicating better function.Visual analogue scale (VAS) was used for pain valuation, total score from 0 to 10, with higher scores indicating more pain. A questionnaire survey on patient satisfaction was conducted at the last follow-up. Shapiro-Wilk test was used for normal distribution test, and measurement data following normal distribution were represented as Mean±SD. Paired t-test was used for comparison before and after operation. Other indicators conformed to non-normal distribution were denoted by M( Q1, Q3) and were tested by Wilcoxon signed-rank test. P<0.05 was considered statistically significant. Results:Fifty-two feet of 48 patients (5 males, 43 females; mean age (52.4±14.9) years; range, 24 to 78 years) were enrolled. Before the operation, 8 feet combined with metatarsalgia, among them, 7 feet underwent modified Chevron+ Akin+ Weil osteotomy, and 1 foot underwent modified Chevron+ Weil osteotomy. Among the 44 feet without metatarsalgia, 11 feet underwent modified Chevron osteotomy and 33 feet underwent modified Chevron+ Akin osteotomy. The mean follow-up time was 17.8 months (12-24 months). The HVA angle decreased from 38.30°±7.59° before surgery to 10.00°±5.73° at the last follow-up; the IMA angle decreased from 16.08°(12.89°, 18.24°) to 4.81°(3.62°, 7.57°); the DMAA angle decreased from 18.35°(13.03°, 27.47°) to 4.52°(2.68°, 7.09°); JCA decreased significantly from 15.93°(10.25°, 23.06°) to 3.56°(1.71°, 6.98°); forefoot bone width decreased from (90.05±6.12) mm to (82.75±5.01) mm; forefoot soft tissue width decrease from 102.25(96.77, 107.15) mm to 98.08(91.01, 100.60) mm; the VAS decreased from 6(5.5, 7) points to 0(0, 0) points; the score according to the AOFAS/HMIS forefoot was increased from 49(42, 52.5) points to 90(83.5, 95) points; which were statistically significant compared with that before the operation (all P<0.01). There was no statistically significant difference in the first metatarsal length before the operation and at the last follow-up [54.60(52.86, 56.42) mm vs. 54.29(51.85, 56.35) mm, P>0.05]. In the post-operative period, there were 8 feet had limited metatarsophalangeal joint movement, 3 feet had limited interphalangeal joint movement, 5 feet had limited movement in both joints, which did not affect walking and function; 3 feet of partial recurrence of hallux valgus, 2 feet of screw irritation pain, 1 foot of cystic degeneration of the first metatarsal head, and no complications such as metastatic metatarsalgia. The satisfaction survey showed that the satisfaction rate of patients with the orthopedic effect was 90.4% (47/52). Conclusion:The modified Chevron osteotomy is effective in the treatment of moderate to severe hallux valgus with enlarged DMAA. Careful intraoperative operation and standardized postoperative rehabilitation training can reduce complications.

Objective:To evaluate the radiological and functional outcomes of moderate to severe hallux valgus patients with enlarged distal metatarsal articular angle (DMAA) underwent modified Chevron osteotomy.Methods:The clinical data of patients with moderate and severe hallux valgus with increased distal metatarsal joint angle who accepted surgery operation in the Department of Foot and Ankle Surgery of Yantaishan Hospital from October 2020 to December 2022 were retrospectively analyzed. All patients underwent modified Chevron osteotomy. Taking the proximal end of the metatarsal head centre as the osteotomy apex, the vertical arm osteotomy line in the sagittal plane made an angle of ≤80° with the metatarsal stem, the horizontal plane was inclined to the lateral distal end of the metatarsal head by about 10°, and the sagittal plane metatarsal arm osteotomy line made an angle of ≥90° with the vertical arm osteotomy line; at the proximal osteotomy surface, another cuneiform bone with its base on the medial and its apex on the lateral was resected. The deformity correction was insufficient and Akin osteotomy was performed in combination. Weil osteotomy was performed in combination with metatarsalgia. Radiological assessment including the hallux valgus angle (HVA), intermetatarsal angle (IMA), DMAA, the joint congruity angle (JCA), forefoot bone width and soft tissue width was performed preoperatively and at last follow-up postoperatively. American Orthopedic Foot and Ankle Society/hallux metatarsophalangeal-interphalangeal scale (AOFAS/HMIS) was used for clinical and functional evaluation, total score from 0 to 100, with higher scores indicating better function.Visual analogue scale (VAS) was used for pain valuation, total score from 0 to 10, with higher scores indicating more pain. A questionnaire survey on patient satisfaction was conducted at the last follow-up. Shapiro-Wilk test was used for normal distribution test, and measurement data following normal distribution were represented as Mean±SD. Paired t-test was used for comparison before and after operation. Other indicators conformed to non-normal distribution were denoted by M( Q1, Q3) and were tested by Wilcoxon signed-rank test. P<0.05 was considered statistically significant. Results:Fifty-two feet of 48 patients (5 males, 43 females; mean age (52.4±14.9) years; range, 24 to 78 years) were enrolled. Before the operation, 8 feet combined with metatarsalgia, among them, 7 feet underwent modified Chevron+ Akin+ Weil osteotomy, and 1 foot underwent modified Chevron+ Weil osteotomy. Among the 44 feet without metatarsalgia, 11 feet underwent modified Chevron osteotomy and 33 feet underwent modified Chevron+ Akin osteotomy. The mean follow-up time was 17.8 months (12-24 months). The HVA angle decreased from 38.30°±7.59° before surgery to 10.00°±5.73° at the last follow-up; the IMA angle decreased from 16.08°(12.89°, 18.24°) to 4.81°(3.62°, 7.57°); the DMAA angle decreased from 18.35°(13.03°, 27.47°) to 4.52°(2.68°, 7.09°); JCA decreased significantly from 15.93°(10.25°, 23.06°) to 3.56°(1.71°, 6.98°); forefoot bone width decreased from (90.05±6.12) mm to (82.75±5.01) mm; forefoot soft tissue width decrease from 102.25(96.77, 107.15) mm to 98.08(91.01, 100.60) mm; the VAS decreased from 6(5.5, 7) points to 0(0, 0) points; the score according to the AOFAS/HMIS forefoot was increased from 49(42, 52.5) points to 90(83.5, 95) points; which were statistically significant compared with that before the operation (all P<0.01). There was no statistically significant difference in the first metatarsal length before the operation and at the last follow-up [54.60(52.86, 56.42) mm vs. 54.29(51.85, 56.35) mm, P>0.05]. In the post-operative period, there were 8 feet had limited metatarsophalangeal joint movement, 3 feet had limited interphalangeal joint movement, 5 feet had limited movement in both joints, which did not affect walking and function; 3 feet of partial recurrence of hallux valgus, 2 feet of screw irritation pain, 1 foot of cystic degeneration of the first metatarsal head, and no complications such as metastatic metatarsalgia. The satisfaction survey showed that the satisfaction rate of patients with the orthopedic effect was 90.4% (47/52). Conclusion:The modified Chevron osteotomy is effective in the treatment of moderate to severe hallux valgus with enlarged DMAA. Careful intraoperative operation and standardized postoperative rehabilitation training can reduce complications.