Anterior cruciate ligament (ACL) injury is a common sports-related injury, and its occurrence is closely related to various genetic factors. In order to summarize and identify the genetic factors associated with ACL injury and reveal the role of these factors in the etiological mechanism, thereby providing a scientific basis for the prevention of ACL injury, we focused on analyzing the genotypes that are strongly associated with ACL injury. Particular emphasis was placed on collagen genes that are closely related to the structure and function of the ligament, such as COL1A1, COL5A1, COL3A1, COL6A1 and COL12A1. Other key genes, such as matrix metalloproteinase (MMP), with single-nucleotide polymorphisms may also play important roles in the ACL injury process. Polymorphisms in COL1A1, COL3A1, COL5A1, and COL12A1 genes in the collagen family have been shown to correlate with ligament strength and reparative capacity, but there are conflicting results from studies in different populations. Certain genotypes (e.g., COL1A1-specific haplotypes) showed protective effects in European and American athletes, whereas no association was found in Middle Eastern or Asian populations, suggesting the influence of differences in genetic background. Among the extracellular matrix-related genes, polymorphisms in the MMP and proteoglycan genes are involved in the mechanism of injury by regulating the balance between extracellular matrix degradation and synthesis. Some of these variants (e.g., MMP3) exhibit sex-specific effects, with significant changes in risk in females carrying specific genotypes. Polymorphisms in apoptosis-regulating genes such as Casp8 and angiogenic pathway genes further emphasize the genetic complexity, and their risk effects vary significantly among different types of sports and mechanisms of injury (e.g., non-contact injuries). The mechanism of ACL injury is complex, and the susceptibility to injury is influenced by a combination of genetic and environmental factors with significant differences between populations and genders.

Objective To investigate whether the geometric triangular relationship between the Blumensaat line and the tibial plateau can serve as an auxiliary diagnostic index for identifying and evaluating anterior cruciate ligament(ACL)injuries,thereby enhancing diagnostic accuracy.Methods A retrospective self-controlled study was conducted involving 64 patients diagnosed with unilateral ACL injury via arthroscopy and treated with ACL reconstruction at Qingdao Municipal Hospital from January to August 2023.Ultimately,40 cases were included in the analysis.Preoperative MRI images of the affected knees and contralateral healthy knees were collected as the ACL injury group and control group,respectively.In the MRI images,point C,point D,and point E were defined as the anterior end,posterior end,and midpoint of the Blumensaat line,respectively;point A and point B were defined as the turning points of the anterior and posterior edges of the tibial plateau,respectively;and point C'was defined as the intersection of the extension line of DC and line AB.Based on these anatomical landmarks,angles ∠DAB,∠CEB,∠DC'B,and ∠CDB were established.The intra-class correlation coefficient(ICC)was calculated to assess measurement consistency and reproducibility.Differences between the aforementioned angles were compared,and the area under the receiver operating characteristic(ROC)curve was computed to evaluate diagnostic performance.Results For ∠CDB,∠DC'B,∠CEB,and ∠DAB,the intra-group and inter-group correlation coefficients all exceeded 0.80,indicating excellent consistency and reproducibility.Compared to the control group,the angles ∠CDB,∠CEB,and ∠DAB in the ACL injury group were significantly reduced(P<0.001).Among these,∠DAB appears to be the most reliable index for diagnosing and evaluating ACL injuries,with an area under the receiver operating characteristic curve(AUC)of 0.829,a cut-off value of 42.2°,a sensitivity of 82.5%,and a specificity of 80.0%.Conclusion The geometric triangular relationship between the Blumensaat line and the tibial plateau in MRI images,particularly the angle ∠DAB,can serve as an auxiliary indicator for diagnosing and evaluating ACL injuries,thereby enhancing diagnostic accuracy.

Objective:To investigate the effect and mechanism of injectable photopolymerizable porous gelatin methacrylate anhydride (Porous GelMA)/methacrylated silk fibroin (SilMA) composite hydrogel (PSE) loaded with human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) in promoting knee joint cartilage regeneration.Methods:The porous GelMA solution (60 g/L) was mixed with SilMA solution (200 g/L) at a volume ratio of 6∶1 . The mixture was ultraviolet-irradiated for 30 seconds to form a cured Porous GelMA/SilMA hydrogel (P/S6). The hUCMSC-Exos was isolated via differential centrifugation coupled with ultrafiltration and then was incorporated into the Porous GelMA/SilMA composite solution at 200 μg/ml, followed by ultraviolet irradiation for 30 seconds to generate Exos-loaded PSE. Primary rat chondrocytes (P1) were divided into control group, P/S6 group, and PSE group to characterize the porosity, compressive strength, and sustained exosome release kinetics of PSE hydrogel. Chondrocytes were allocated to control group, interleukin-1β (IL-1β) group, P/S6 group, and PSE group, among which the last three groups were preconditioned with 10 ng/ml IL-1β for 24 hours, and then cultured in complete medium, P/S6 extract and PSE extract for 3 days, respectively, to establish in vitro cartilage defect models, while the control group remained untreated. Western blot and qRT-PCR analysis were conducted to quantify the expression levels of antibody to aggrecan core protein (ACAN), sex-determining region Y-box transcription factor 9 (SOX9), matrix metalloproteinase-13 (MMP13) and collagen type II (COL II). Murine monocyte-macrophage leukemia cells (RAW264.7) were divided into control group, P/S6 group, and PSE group, which were then cultured in complete medium, PSE extract, and PSE extract medium for 3 days, respectively. qRT-PCR was employed to detect the expression levels of recombinant arginase-1 protein (ARG1), mannose receptor (CD206), and inducible nitric oxide synthase (iNOS). Transcriptomic sequencing was used to identify differentially expressed genes during PSE-mediated chondrocyte regeneration, followed by functional enrichment analysis of key signaling pathways. Twenty-four SD rats were selected to establish cartilage defect models and assigned to injury control group, P/S6 group, and PSE group according to the random number table (8 rats per group). The right knee joints of the rats were surgically exposed, and cylindrical osteochondral defects (a diameter of 2.0 mm× a depth of 1.0 mm) were surgically created in the center of the femoral trochlear groove using a drill bit. The injury control group received phosphate-buffered saline, while the P/S6 group and PSE group were injected with corresponding hydrogels followed by photo-crosslinking. Incisions then were closed in layers. At 6 and 10 weeks after injury, specimens were harvested for HE staining and safranin O-fast green staining to evaluate cartilage regeneration and immunohistochemistry staining to quantify the positive area fractions for COL II, MMP13, ARG1, and CD206 in the defect areas. Results:PSE hydrogel exhibited compressive strength matching native cartilage (0.41 MPa), high porosity (85%), and sustained exosome release capacity (cumulative release rate of approximately 85% over 14 days). In chondrocyte repair experiments, compared to the IL-1β group, the PSE group demonstrated significantly upregulated expression of anabolic markers of cartilage (COL II expression increased by 2.1-fold, ACAN by 1.8-fold, and SOX9 by 1.5-fold) ( P<0.01) as well as significantly suppressed expression of catabolic markers (MMP13 expression decreased by 52%) ( P<0.01). In macrophage polarization assays, the PSE group exhibited ARG1 expression increased by 68% when compared to the control group ( P<0.01), thus promoting M2 polarization of macrophages. Transcriptomic analysis revealed that PSE enhanced extracellular matrix (ECM) synthesis by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway and ECM-receptor interaction pathway, as well as by suppressing inflammation-related gene expression. Histological evaluation in animal experiments revealed regeneration of hyaline cartilage with smooth, continuous surfaces in the defect areas in the PSE group. At 10 weeks after surgery, the neocartilage-positive area in the PSE group was (9.94±0.26)%, significantly larger than (1.67±0.11)% in the injury control group ( P<0.01). Besides, the CD206? M2 macrophage-positive area reached (14.44±0.23)% in the PSE group, significantly larger than (3.41±0.36)% in the injury control group ( P<0.01). Conclusions:The PSE hydrogel successfully engineered in the study can significantly promote regenerative repair of knee cartilage defects through a dual mechanism of enhanced ECM anabolism and remodeled inflammatory microenvironment. The core mechanisms involve specific activation of the PI3K/Akt pathway (boosting chondrocyte proliferation and survival) and ECM-receptor interaction pathway (driving ECM synthesis and assembly) by exosome-loaded PSE, while effectively polarizing macrophages toward an anti-inflammatory M2 phenotype so as to coordinately regulate cartilage ECM metabolism and suppress inflammatory responses.

With the rapid development of competitive sports, the incidence of anterior cruciate ligament (ACL) injury is on the rise. Such injuries may shorten athletes′ career and lead to other long-term adverse consequences. Although athletes generally recover well after ACL reconstruction, many still struggle to return to their pre-injury performance levels. Advances in the understanding of ACL anatomy and injury mechanisms, along with the evolution of surgical techniques and rehabilitation methods, have provided more individualized and tailored options for athletes following ACL injuries. However, there is currently no consensus in China regarding surgical and rehabilitation strategies for competitive athletes aiming to return to sports after ACL injuries. To this end, the Sports Medicine Committee of the Chinese Research Hospital Association and the Editorial Board of the Chinese Journal of Trauma jointly formulated the Expert consensus on surgical treatment and rehabilitation for competitive sports athletes returning to sports after anterior cruciate ligament injury ( version 2025), and presented 14 recommendations covering surgical indications, preoperative rehabilitation, surgical timing, surgical strategies and postoperative rehabilitation strategies, aiming to improve the surgical treatment and rehabilitation system for ACL injuries in competitive athletes and facilitate their return to high-level sports performance after injury.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Acute lateral ankle sprain (ALAS) is one of the most common sport injuries, with high incidence, recurrence and disability rates. Currently, exercise rehabilitation-based non-surgical treatment is the primary management approach for ALAS. However, there remain improper practices such as excessive immobilization or uncontrolled activity, which contribute to recurrent sprains and chronic ankle instability, significantly impairing patients′ athletic function and quality of life. To standardize the non-surgical management of ALAS, improve the cure rates, and reduce the recurrence and disability rates, Chinese Sports Rehabilitation Medicine Training Project of Chinese Medical Association, Foot and Ankle Basics and Orthopedics Group, Orthopedic Branch of Chinese Medical Doctor Association, and Sports Medicine Branch of Jiangsu Medical Association organized relevant experts to formulate Expert consensus on non-surgical treatment for acute lateral ankle sprain ( version 2025), following the principles of scientific vigor, practicality, and innovation. Thirteen recommendations were proposed for standardized treatment protocols across different healing phases, aiming to provide references for standard management of ALAS and improve the therapeutic outcomes.

Objective To investigate whether the geometric triangular relationship between the Blumensaat line and the tibial plateau can serve as an auxiliary diagnostic index for identifying and evaluating anterior cruciate ligament(ACL)injuries,thereby enhancing diagnostic accuracy.Methods A retrospective self-controlled study was conducted involving 64 patients diagnosed with unilateral ACL injury via arthroscopy and treated with ACL reconstruction at Qingdao Municipal Hospital from January to August 2023.Ultimately,40 cases were included in the analysis.Preoperative MRI images of the affected knees and contralateral healthy knees were collected as the ACL injury group and control group,respectively.In the MRI images,point C,point D,and point E were defined as the anterior end,posterior end,and midpoint of the Blumensaat line,respectively;point A and point B were defined as the turning points of the anterior and posterior edges of the tibial plateau,respectively;and point C'was defined as the intersection of the extension line of DC and line AB.Based on these anatomical landmarks,angles ∠DAB,∠CEB,∠DC'B,and ∠CDB were established.The intra-class correlation coefficient(ICC)was calculated to assess measurement consistency and reproducibility.Differences between the aforementioned angles were compared,and the area under the receiver operating characteristic(ROC)curve was computed to evaluate diagnostic performance.Results For ∠CDB,∠DC'B,∠CEB,and ∠DAB,the intra-group and inter-group correlation coefficients all exceeded 0.80,indicating excellent consistency and reproducibility.Compared to the control group,the angles ∠CDB,∠CEB,and ∠DAB in the ACL injury group were significantly reduced(P<0.001).Among these,∠DAB appears to be the most reliable index for diagnosing and evaluating ACL injuries,with an area under the receiver operating characteristic curve(AUC)of 0.829,a cut-off value of 42.2°,a sensitivity of 82.5%,and a specificity of 80.0%.Conclusion The geometric triangular relationship between the Blumensaat line and the tibial plateau in MRI images,particularly the angle ∠DAB,can serve as an auxiliary indicator for diagnosing and evaluating ACL injuries,thereby enhancing diagnostic accuracy.

Anterior cruciate ligament (ACL) injury is a common sports-related injury, and its occurrence is closely related to various genetic factors. In order to summarize and identify the genetic factors associated with ACL injury and reveal the role of these factors in the etiological mechanism, thereby providing a scientific basis for the prevention of ACL injury, we focused on analyzing the genotypes that are strongly associated with ACL injury. Particular emphasis was placed on collagen genes that are closely related to the structure and function of the ligament, such as COL1A1, COL5A1, COL3A1, COL6A1 and COL12A1. Other key genes, such as matrix metalloproteinase (MMP), with single-nucleotide polymorphisms may also play important roles in the ACL injury process. Polymorphisms in COL1A1, COL3A1, COL5A1, and COL12A1 genes in the collagen family have been shown to correlate with ligament strength and reparative capacity, but there are conflicting results from studies in different populations. Certain genotypes (e.g., COL1A1-specific haplotypes) showed protective effects in European and American athletes, whereas no association was found in Middle Eastern or Asian populations, suggesting the influence of differences in genetic background. Among the extracellular matrix-related genes, polymorphisms in the MMP and proteoglycan genes are involved in the mechanism of injury by regulating the balance between extracellular matrix degradation and synthesis. Some of these variants (e.g., MMP3) exhibit sex-specific effects, with significant changes in risk in females carrying specific genotypes. Polymorphisms in apoptosis-regulating genes such as Casp8 and angiogenic pathway genes further emphasize the genetic complexity, and their risk effects vary significantly among different types of sports and mechanisms of injury (e.g., non-contact injuries). The mechanism of ACL injury is complex, and the susceptibility to injury is influenced by a combination of genetic and environmental factors with significant differences between populations and genders.

Objective:To investigate the effect and mechanism of injectable photopolymerizable porous gelatin methacrylate anhydride (Porous GelMA)/methacrylated silk fibroin (SilMA) composite hydrogel (PSE) loaded with human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) in promoting knee joint cartilage regeneration.Methods:The porous GelMA solution (60 g/L) was mixed with SilMA solution (200 g/L) at a volume ratio of 6∶1 . The mixture was ultraviolet-irradiated for 30 seconds to form a cured Porous GelMA/SilMA hydrogel (P/S6). The hUCMSC-Exos was isolated via differential centrifugation coupled with ultrafiltration and then was incorporated into the Porous GelMA/SilMA composite solution at 200 μg/ml, followed by ultraviolet irradiation for 30 seconds to generate Exos-loaded PSE. Primary rat chondrocytes (P1) were divided into control group, P/S6 group, and PSE group to characterize the porosity, compressive strength, and sustained exosome release kinetics of PSE hydrogel. Chondrocytes were allocated to control group, interleukin-1β (IL-1β) group, P/S6 group, and PSE group, among which the last three groups were preconditioned with 10 ng/ml IL-1β for 24 hours, and then cultured in complete medium, P/S6 extract and PSE extract for 3 days, respectively, to establish in vitro cartilage defect models, while the control group remained untreated. Western blot and qRT-PCR analysis were conducted to quantify the expression levels of antibody to aggrecan core protein (ACAN), sex-determining region Y-box transcription factor 9 (SOX9), matrix metalloproteinase-13 (MMP13) and collagen type II (COL II). Murine monocyte-macrophage leukemia cells (RAW264.7) were divided into control group, P/S6 group, and PSE group, which were then cultured in complete medium, PSE extract, and PSE extract medium for 3 days, respectively. qRT-PCR was employed to detect the expression levels of recombinant arginase-1 protein (ARG1), mannose receptor (CD206), and inducible nitric oxide synthase (iNOS). Transcriptomic sequencing was used to identify differentially expressed genes during PSE-mediated chondrocyte regeneration, followed by functional enrichment analysis of key signaling pathways. Twenty-four SD rats were selected to establish cartilage defect models and assigned to injury control group, P/S6 group, and PSE group according to the random number table (8 rats per group). The right knee joints of the rats were surgically exposed, and cylindrical osteochondral defects (a diameter of 2.0 mm× a depth of 1.0 mm) were surgically created in the center of the femoral trochlear groove using a drill bit. The injury control group received phosphate-buffered saline, while the P/S6 group and PSE group were injected with corresponding hydrogels followed by photo-crosslinking. Incisions then were closed in layers. At 6 and 10 weeks after injury, specimens were harvested for HE staining and safranin O-fast green staining to evaluate cartilage regeneration and immunohistochemistry staining to quantify the positive area fractions for COL II, MMP13, ARG1, and CD206 in the defect areas. Results:PSE hydrogel exhibited compressive strength matching native cartilage (0.41 MPa), high porosity (85%), and sustained exosome release capacity (cumulative release rate of approximately 85% over 14 days). In chondrocyte repair experiments, compared to the IL-1β group, the PSE group demonstrated significantly upregulated expression of anabolic markers of cartilage (COL II expression increased by 2.1-fold, ACAN by 1.8-fold, and SOX9 by 1.5-fold) ( P<0.01) as well as significantly suppressed expression of catabolic markers (MMP13 expression decreased by 52%) ( P<0.01). In macrophage polarization assays, the PSE group exhibited ARG1 expression increased by 68% when compared to the control group ( P<0.01), thus promoting M2 polarization of macrophages. Transcriptomic analysis revealed that PSE enhanced extracellular matrix (ECM) synthesis by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway and ECM-receptor interaction pathway, as well as by suppressing inflammation-related gene expression. Histological evaluation in animal experiments revealed regeneration of hyaline cartilage with smooth, continuous surfaces in the defect areas in the PSE group. At 10 weeks after surgery, the neocartilage-positive area in the PSE group was (9.94±0.26)%, significantly larger than (1.67±0.11)% in the injury control group ( P<0.01). Besides, the CD206? M2 macrophage-positive area reached (14.44±0.23)% in the PSE group, significantly larger than (3.41±0.36)% in the injury control group ( P<0.01). Conclusions:The PSE hydrogel successfully engineered in the study can significantly promote regenerative repair of knee cartilage defects through a dual mechanism of enhanced ECM anabolism and remodeled inflammatory microenvironment. The core mechanisms involve specific activation of the PI3K/Akt pathway (boosting chondrocyte proliferation and survival) and ECM-receptor interaction pathway (driving ECM synthesis and assembly) by exosome-loaded PSE, while effectively polarizing macrophages toward an anti-inflammatory M2 phenotype so as to coordinately regulate cartilage ECM metabolism and suppress inflammatory responses.

With the rapid development of competitive sports, the incidence of anterior cruciate ligament (ACL) injury is on the rise. Such injuries may shorten athletes′ career and lead to other long-term adverse consequences. Although athletes generally recover well after ACL reconstruction, many still struggle to return to their pre-injury performance levels. Advances in the understanding of ACL anatomy and injury mechanisms, along with the evolution of surgical techniques and rehabilitation methods, have provided more individualized and tailored options for athletes following ACL injuries. However, there is currently no consensus in China regarding surgical and rehabilitation strategies for competitive athletes aiming to return to sports after ACL injuries. To this end, the Sports Medicine Committee of the Chinese Research Hospital Association and the Editorial Board of the Chinese Journal of Trauma jointly formulated the Expert consensus on surgical treatment and rehabilitation for competitive sports athletes returning to sports after anterior cruciate ligament injury ( version 2025), and presented 14 recommendations covering surgical indications, preoperative rehabilitation, surgical timing, surgical strategies and postoperative rehabilitation strategies, aiming to improve the surgical treatment and rehabilitation system for ACL injuries in competitive athletes and facilitate their return to high-level sports performance after injury.