BACKGROUND:Degenerative medial meniscal tears (DMMTs) pose challenges in surgical management, with varying repair outcomes. This study aimed to identify preoperative factors associated with early clinical failure after isolated arthroscopic meniscal repair of DMMTs. METHODS:This study retrospectively reviewed data from patients (mean age, 49.0 ± 9.1 years) who underwent isolated all-inside medial meniscal repair at two institutions (2018-2025). The evaluated potential predictors included patient characteristics (demographics, symptom duration), radiographic alignment measures (Kellgren-Lawrence grade, percentage of the mechanical axis [%MA] as a continuous variable, and %MA<30 % as a categorical cutoff, medial proximal tibial angle), magnetic resonance imaging findings (joint effusion, defined by an effusion-synovitis score of ≥1 based on the magnetic resonance imaging Osteoarthritis Knee Score; cartilage damage; bone marrow lesions), and meniscal tear features (location, morphology). Significant variables identified through univariate analysis were included in the multivariate logistic regression. RESULTS:Forty-three knees were analyzed (23 successes [54 %], 20 failures [46 %]). The Kellgren-Lawrence grade based on preoperative radiographs was distributed as follows: 0/1/2 = 9/26/8. On preoperative MRI, cartilage damage was observed for 14 knees (32.6 %). Failures had a higher prevalence of preoperative effusion (85.0 % vs 30.4 %, p = 0.001) and lower mean %MA (36.8 ± 12.3 vs 44.7 ± 12.0, p = 0.036). %MA<30 % was more frequent among failures (40.0 % vs 8.7 %, p = 0.028). Multivariate analysis identified preoperative effusion (odds ratio [OR]: 17.7, 95 % confidence interval [CI]: 3.6-178.0, p < 0.001) and %MA<30 % (OR: 12.4, 95 % CI: 1.8-166.6, p = 0.008) as independent predictors of failure. CONCLUSIONS:Preoperative joint effusion and varus malalignment (%MA<30 %) were significant predictors of early clinical failure 6 months after isolated arthroscopic meniscal repair for DMMTs.

Background:The quadriceps tendon (QT) has recently gained attention as a graft tendon for anterior cruciate ligament (ACL) reconstruction due to its high strength from a larger ultrastructural collagen fibril diameter in children than that of the semitendinosus tendon. While QT collagen fibril diameter increases with growth, changes in older adults remain unclear. This study investigated age-related changes in QT collagen fibril diameter. Methods:Twenty-four patients who had undergone ACL reconstruction using the QT or other knee surgeries were included. QT tissues collected during surgery were analyzed using transmission electron microscopy. Collagen fibril diameter was measured in four groups: Immature (11-13 years), Young (15-17 years), Adult (21-50 years), and Older (61-81 years). The average fibril diameter was calculated for each sample. At least four slides (one slide = one digital electron micrographs of the ultrathin section) were evaluated for each specimen, with at least 200 collagen fibrils on each slide. The average number of collagen fibrils measured per specimen was 812 ± 10. Data of the four groups were analyzed using one-way analysis of variance and Tukey's test. Results:The mean collagen fibril diameters were 89.7 ± 14.4, 94.8 ± 16.4, 107.2 ± 12.1, and 73.0 ± 9.7 nm in the Immature, Young, Adult, and Older groups, respectively. Although no significant difference was observed between the Immature and Young groups, fibril diameter was significantly larger in the Adult group than in the Young group and significantly smaller in the Older group than in the other groups. Conclusions:The average QT collagen fibril diameter increased with growth but was lower in the Older group, suggesting a decrease with aging.

BACKGROUND:A lateral meniscal posterior root tear (LMPRT) is a known complication of anterior cruciate ligament (ACL) injury. Complete repair of meniscal posterior root tears is essential for preventing degenerative changes in the knee that may result from meniscal extrusion and rotational instability. This study aimed to assess the relationship between LMPRT morphology and preoperative lateral meniscal extrusion (LME) and to determine the cutoff value for complete LMPRT based on preoperative LME measurements. METHODS:We retrospectively analyzed 403 patients who underwent ACL reconstruction at our hospital between 2011 and 2021. The study finally included 35 patients with LMPRT and 20 with an intact lateral meniscus (LM) as controls. Based on the arthroscopic findings during ACL reconstruction, the 35 patients were divided into two groups: partial (type 1) and complete (types 2-5) LMPRT, in accordance with the LaPrade Classification. The degree of LME was measured using magnetic resonance imaging (MRI). RESULTS:The partial LMPRT group comprised 17 knees (10 male and 7 female patients), and the complete LMPRT group comprised 18 knees (9 male and 9 female patients). MRI revealed notably greater preoperative LME measurements in cases of complete LMPRT than in cases of both partial LMPRT and intact LM. Receiver operating curve analysis established the optimal cutoff threshold of 2.2 mm for a preoperative LME, with a sensitivity of 78 % and specificity of 71 % for predicting complete LMPRT. CONCLUSIONS:The findings of this study indicate a higher degree of LME in complete LMPRT than in partial LMPRT in knees with ACL injury. Additionally, in patients with ACL injuries, a preoperative MRI measurement of LME ≥2.2 mm suggests a greater likelihood of complete LMPRT.

Purpose:Medial meniscal extrusion is a key factor in accelerating knee osteoarthritis. Medial joint line obliquity causes increased contact pressure on the medial meniscus, which potentially induces medial meniscal extrusion. Our hypothesis was that medial joint line obliquity contributes to an increase in medial meniscal extrusion in both supine and upright position during early-stage knee osteoarthritis (KOA). Methods:We analysed 124 knees with early-stage KOA. Medial joint line obliquity (knee joint line obliquity ≤ - 3°) and posterior tibial slope ( ≥ 6°) were assessed using standing full-length lower extremity radiography and magnetic resonance imaging, respectively. Medial meniscal extrusion was measured using ultrasonography in the supine and upright positions. Cases with excessive posterior tibial slope were excluded to minimise the influence of the posterior tibial slope, and the remaining 89 knees were divided into medial joint line obliquity (n = 45; age = 58.3 ± 10.5 years) and control groups (n = 44; age = 59.8 ± 11.9 years). Each measurement was compared between the two groups using t-test or chi-square test. Multiple regression analysis was performed to determine the independent factor for medial meniscal extrusion. Results:The medial joint line obliquity group showed significantly higher medial meniscal extrusion than the control group (supine, 3.0 ± 1.0 vs. 2.4 ± 0.9 mm, p = 0.004; upright, 3.7 ± 1.0 vs. 3.2 ± 1.1 mm, p = 0.023). Meniscal tear was present in 75.6% and 75% of the medial joint line obliquity and control groups, respectively, with no significant difference in tear type distribution (p = 0.999). Medial joint line obliquity and medial meniscus tear were independent factors for increased medial meniscal extrusion in both the supine (p = 0.002 and p = 0.003, respectively) and upright positions (p = 0.017 and p = 0.001, respectively). Conclusion:Medial joint line obliquity and medial meniscus tear may be risk factors for medial meniscal extrusion in both the supine and upright positions in early-stage KOA. Level of Evidence:Level IV.

BACKGROUND:Evaluating the correlation between degenerative meniscus tears and medial meniscus extrusion is necessary to determine the appropriate treatment plan for early-stage knee osteoarthritis. This study evaluated the relationship between degenerative meniscal tears and medial meniscus extrusion in early-stage knee osteoarthritis by using ultrasonography. METHODS:A total of 132 knees from 123 patients with early-stage knee osteoarthritis were evaluated retrospectively. Medial meniscus extrusion at knee flexion angles of 0° and 90°, and meniscal degenerative tears, were evaluated using ultrasonography and magnetic resonance imaging. Medial meniscus extrusion was classified into four grades, while degenerative meniscal tears were categorized into five types as follows: type 0, no tear or only degenerative changes; type 1, horizontal tear only in the posterior segment of the medial meniscus; type 2, horizontal tear shown in both the posterior and middle segments of the medial meniscus; type 3, flap tear or maceration of the medial meniscus; type 4, medial meniscus posterior root tear or radial tear. Correlations between the type of meniscal tear and the medial meniscus extrusion grade in each meniscal tear group were evaluated. RESULTS:The meniscal tear type was significantly correlated with the medial meniscus extrusion grade (r = 0.518, p = 0.001). The percentages of cases with medial meniscus extrusion grade 2 or 3 (i.e., medial meniscus extrusion >3 mm at knee flexion angle of 0°) were 23.8 %, 50.0 %, 86.8 %, 94.1 %, and 92.3 % for types 0-4, respectively. The percentages of cases with medial meniscus extrusion >3 mm at knee flexion angles of 0° and 90° were 0 %, 20.0 %, 52.6 %, 70.6 %, and 50.0 % for types 0-4, respectively. CONCLUSION:The more severe the meniscal degenerative tear, the greater the medial meniscus extrusion and the more abnormal the dynamics in early-stage knee osteoarthritis.

PURPOSE:Medial meniscus posterior root tear (MMPRT) is a critical condition leading to knee osteoarthritis. Although MRI is the standard diagnostic tool, its availability and cost can be limiting. This study aimed to identify characteristic ultrasound (US) findings of MMPRT and determine the criteria for recommending MRI. METHODS:This multicenter prospective study included 100 patients (101 knees, mean age 58.3 ± 11.2 years, 58 males and 42 females) with medial knee joint pain. All patients underwent US and MRI evaluations. US findings included joint effusion, synovial hypertrophy, and medial meniscus extrusion (MME) in the supine, 90° flexion, and standing positions. Color Doppler evaluation of Doppler signals (DSs) in the bursa and through the femur and tibia were performed. Statistical analysis compared US findings between MMPRT and non-MMPRT groups. RESULTS:The MMPRT group showed significantly higher rates of joint effusion (p = 0.028) and increased MME in all positions (p < 0.001). MME changed from 0° to 90° knee flexion (p = 0.003). Color Doppler evaluations revealed DSs through the femur (p = 0.008) and tibia (p = 0.013). Horizontal meniscal tears were more frequent in the non-MMPRT group (p < 0.001). For three or more positive parameters, sensitivity and specificity were 80% and 82.7%, respectively. CONCLUSION:Five key US findings-joint effusion, increased MME, smaller MME change in knee flexion, fewer horizontal meniscal tears, and increased DSs through the femur and tibia-are characteristic of MMPRT. These suggest that US can effectively identify patients requiring MRI, facilitating early management.

Lettuce (Lactuca sativa L.) is an economically important leafy vegetable crop around the world. Recently, transgenic lettuce has been developed to improve agronomic traits. Although plant regeneration is a key step in plant genetic transformation, it depends strongly on the cultivar. In this study, shoot regeneration efficiency was measured by using two leaf lettuce cultivars, Chima-sanchi, white seed cultivar, and Chirimen-chisya, brown seed cultivar, a basal salt mixture, and a combination of the cytokinin, 6-benzylaminopurine (BAP), and an auxin, 1-naphthaleneacetic acid (NAA). Efficient shoot regeneration in Chima-sanchi was thus obtained on 1 x Murashige and Skoog medium (MS) with 0.05 mg L-1 BAP and 0.1 mg L-1 NAA. However, the highest efficiency was obtained in Chirimen-chisya on 1 x MS with 0.5 mg L-1 BAP and 0.1 mg L-1 NAA. Therefore, the BAP concentration for efficient shoot regeneration differs significantly between the two cultivars. These cultivars also have different seed coat colors. Due to the similar results obtained from analyzing 4 additional cultivars, 2 white seed cultivars and 2 brown seed cultivars, we demonstrated a strong correlation between the BAP concentration for efficient shoot regeneration and the seed coat color in leaf lettuce. ### Competing Interest Statement The authors have declared no competing interest.

BACKGROUND: Foot rock-paper-scissors and towel-gathering exercises are widely used for isometric strengthening of intrinsic foot muscles. An initial trial demonstrated that foot rock-paper-scissors and towel-gathering exercises affected skeletal muscles associated with the medial longitudinal arch and toe pressure force, respectively. However, no quantitative reports of interosseous muscle activity after continuous training exist. We aimed to quantitatively assess and compare the impact of foot rock-paper-scissors and towel-gathering exercises on skeletal muscle activity in university athletes over a 3-month period using FDG-PET 3 imaging. METHODS: This randomized controlled clinical trial was conducted in a university hospital with pre- and post-training PET measurements of muscle activity changes. Eight healthy university athletes were subjected to two 3-month-long exercise regimens: foot rock-paper-scissors and towel-gathering. Skeletal muscle activity changes were quantitatively evaluated using FDG-PET imaging. We defined regions of interest across 25 specific muscles and conducted measurements of toe pressure strength and vertical jump height. RESULTS: The foot rock-paper-scissors exercise initially impacted medial muscles and later intrinsic foot muscles, including lateral longitudinal arch muscles. The towel-gathering exercise improved toe pressure force and vertical jump. Therefore, each exercise targets specific muscle groups differently. CONCLUSIONS: Foot rock-paper-scissors and towel-gathering exercises have distinct effects on skeletal muscle activity. The former primarily enhances medial intrinsic muscles, while the latter improves toe pressure force and vertical jump ability. This highlights the importance of selecting specific exercises for targeted muscle training in athletic and rehabilitation settings. Further research is suggested to extend these findings to broader athletic populations and clinical applications.

Objective: This prospective study aimed to investigate the relationship between preoperative psychological competitive ability and preoperative and 6 months postoperative subjective knee function in patients undergoing anterior cruciate ligament (ACL) reconstruction. Methods: Eighty-four patients who underwent ACL reconstruction and had a Tegner Activity Scale score of 6 or more were included in this study. Preoperatively, all patients were administered the Diagnostic Inventory of Psychological Competitive Ability for Athletes (DIPCA.3) for psychological competitive ability assessment and the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form for subjective knee function assessment. The IKDC subjective score was re-evaluated 6 months postoperatively. We evaluated the associations of volition for competition, mental stability and concentration, confidence, strategic ability, and cooperation (DIPCA.3 factors) with the IKDC subjective score preoperatively and 6 months postoperatively. Furthermore, patients were classified into two groups according to whether they could return to participate in the entire practice and compared the DIPCA.3 total score and IKDC subjective score. Results: The DIPCA.3 confidence score negatively correlated with the preoperative IKDC subjective score (beta = -0.34, p = 0.04). However, there was no association between the DIPCA.3 score for all variables and IKDC subjective score at 6 months after ACL reconstruction. Moreover, the DIPCA.3 total score was not related to return to participate in the entire practice 6 months after ACL reconstruction. Conclusion: Psychological competitive ability is not associated with a return to participate in the entire practice, and a low preoperative IKDC subjective score should not be viewed too negatively.

Background Psychological state has been reported as one of the factors strongly related to a return to sports after anterior cruciate ligament (ACL) reconstruction. However, its relationship with the emotional state remains unclear. The aim of this study was to investigate whether patients who have undergone ACL reconstruction and have a higher preoperative psychological competitive ability have a better emotional status preoperatively and six months postoperatively. Methods Patients with a Tegner activity score of ≥6 who underwent ACL reconstruction between 2015 and 2020 were divided into two groups according to their grades on the Diagnostic Inventory of Psychological Competitive Ability for Athletes (DIPCA.3). The emotional states preoperatively and at six months postoperatively were assessed using the Profile of Mood States Second Edition (POMS2) and compared between the two groups. Furthermore, the possibility of returning to sports was compared between the groups based on participation in the entire practice at six months postoperatively. Results Eighty-four patients were included and divided into the high (DIPCA.3 grades ≥4, n = 23) and low (DIPCA.3 <4, n = 61) groups. Vigor-activity and friendliness were significantly higher in the high group than in the low group preoperatively. The difference was even greater at six months after ACL reconstruction. In addition, the high group showed significantly better results postoperatively for fatigue-inertia and total mood disturbance. Rates of return to sports did not differ significantly between the high and low groups (56.5% vs. 54.1%). Conclusions Those with a higher preoperative psychological competitive ability were in a positive emotional state preoperatively and six months after ACL reconstruction. However, the psychological competitive ability did not affect the rate of participation in the entire practice at six months postoperatively.

Intracellular delivery of biomolecules is a prerequisite for genetic techniques such as recombinant engineering and genome editing. Realizing the full potential of this technology requires the development of safe and effective methods for delivering protein tools into cells. In this study, we demonstrated the spontaneous internalization of exogenous proteins into intact cells and root tissue of whole plants of Arabidopsis thaliana. We termed this internalization phenomenon as protein Delivery Independent of Vehicles or Equipment (DIVE), which efficiently delivered genome engineering proteins including Cre recombinase and zinc-finger nucleases (ZFN) into plant cells. Using protein DIVE, we achieved less toxic protein delivery than electroporation with up to 94% efficiency in Arabidopsis cell culture and 19% genome modification in Arabidopsis plants that was maintained in regenerated tissue. This work illustrates the potential of protein DIVE for a wide range of applications, including genome engineering in plants.

PurposeWe aimed to explore the applicability and validity of ultrasonography for diagnosing chronic posterior cruciate ligament (PCL) injuries.MethodsPCL thickness was measured at 2 cm proximal to the tibia insertion site. Using the same ultrasonography image, the angle tangent to the PCL from the tibia insertion site was also measured. These data were analyzed by plotting the receiver operating curve (ROC), and the sensitivity and specificity were calculated according to the optimal cut-off point. Ultrasonography data from the PCLinjured knee were compared with those from the contralateral uninjured knee of the same patient.ResultsTwelve men and six women, with a mean age of 28.8 +/- 14.0 years, were included in this study. The mean time from injury to medical examination was 10.0 +/- 6.7 months. The mean thickness of the PCL was 8.1 +/- 1.9 mm on the affected side and 5.8 +/- 1.2 mm on the uninjured side, with the affected side being significantly thicker. ROC analysis revealed that the optimal cut-off value for the thickness of chronic PCL injuries was 6.5 mm (sensitivity 83.3%, specificity 77.8%, area under the curve [AUC] = 0.87). The optimal cut-off value for the angle was 20 degrees (sensitivity 88.9%, specificity 94.4%, AUC = 0.96).ConclusionUltrasonography is useful as a screening tool for chronic PCL injuries. The optimal cut-off point was 6.5 mm for thickness and 20 degrees for angle.Level of evidenceIV.

Blood flow signals (BFSs) through the bone cortex on ultrasonography (US) and bone marrow lesions (BMLs) detected on magnetic resonance imaging (MRI) can be used to assess bone lesions; however, no studies have reported their relationship. Therefore, this study aimed to assess whether BFSs through the bone cortex on US can serve as a screening test for detecting BMLs on MRI in patients with early knee osteoarthritis (OA). This study enrolled patients with knee joint pain who were diagnosed with early knee OA between January 2018 and January 2024. We targeted 77 patients who underwent MRI and in whom the presence or absence of BFSs through the bone cortex was confirmed on US. The association between BFSs and BMLs was evaluated using the chi-square test, and the sensitivity and specificity of BFSs for detecting BMLs on MRI were calculated. The chi-square test showed that BFSs and BMLs were significantly associated in the femur and tibia (femur: χ2 [1] = 52.9, p < 0.001; Tibia: χ2 [1] = 44.8, p < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of BFSs for detecting BMLs on MRI were 85.0

Similar functional outcome but impaired health related quality of life with bilateral ACL surgery.Data: Introduction: A patient with an ACL-reconstructed knee (ACLR), has a great risk of sustaining a new ACL injury in either knee.Paterno et al. reported that in an active, young population who returned to pivoting activities that 25.4% sustained a new ACL injury.75% of these injuries were to the contralateral knee.Data from the Swedish Knee Ligament Registry report a contralateral ACLR rate of close to 5% at a 5-year follow-up after primary ACLR.The purpose of this study was to 1, identify pre-, intra-and postoperative risk factors associated with contralateral ACLR 2, compare knee laxity and functional knee outcome between primary and contralateral ACLR and 3, compare activity level, patient-reported knee function at a minimum of 5 years follow-up.Methods: 1, Primary ACLR, 2005-2014 (n¼ 5393) and occurrence of a contralateral ACLR within 5 years.Regression analysis [age, gender, body mass index, time from injury to surgery, pre-injury Tegner], intraoperative [graft type, meniscus injury, cartilage injury] and postoperative [limb symmetry index (LSI) for quadriceps and hamstring strength and single-leg-hop test performance] as risk factors for a contralateral ACLR.2, Same patients who underwent primary and contralateral ACLR (n¼ 326).The KT-1000 for knee laxity and KOOS for subjective outcome.3, Bilateral ACLR, ¼ 40 years.KOOS, EQ-5D and EQ-VAS and study-specific questions regarding activity level and knee function at a minimum 5-year follow-up.For every patient with a bilateral ACLR, a control matched for age AE 2 years, gender, year of ACLR and pre-injury activity level or sport at the time of injury was identified.Results: 1, The overall incidence of a contralateral ACLR within 5 years was 4.7%.Multivariable analysis revealed that the risk of contralateral ACLR was significantly affected by age (OR 0.40; 95% CI 0.28 -0.58; P < 0.001), time from injury to surgery (OR 0.48; 95% CI 0.30 -0.75; P ¼ 0.001) and singleleg-hop test (OR 1.56; 95% CI 1.04 -2.34; P ¼ 0.03).2, The mean preoperative and postoperative anterior tibial translation (ATT) and ATT reduction were not different between primary and contralateral ACLR.No significant differences were found for any of the five KOOS subscales at 2 years.3, A total of 98 patients (mean age ?SD, 33.3 ?7.3) with a bilateral ACLR and 98 patients with unilateral ACLR (mean age ?SD, 33.1 ?7.7) were included.The mean postoperative followup was 7.6 AE 1.8 years.Patients with a bilateral ACLR reported lower scores on all KOOS subscales, the EQ-5D and the EQ-VAS at follow-up (P < .05).There was no difference in activity level between the groups at the follow-up, but patients with a bilateral ACLR were less satisfied with their activity level and knee function (P < .05).Conclusion: The 5-year incidence of contralateral ACLR was 4,7%.Most important risk factors were good functional outcome at 6 months follow-up.Knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR but long term patient-reported knee function and health-related quality of life were inferior in patients with a bilateral ACLR compared to patients with a unilateral ACLR.

To compare the biomechanical strength of different fixation configurations using a suspensory button in a soft-tissue quadriceps tendon graft for Anterior Cruciate Ligament (ACL) reconstruction. Thirty fresh-frozen bovine Achilles tendons (10 mm wide, 50 mm long, and 4 mm thick) were used in this study. Tendons were assigned to three groups (n = 10 per group) with different suture configurations using adjustable loops with a suspensory button: group A, with the threads of an adjustable loop fixed by crossing at the tip of the loop and the entire loop; group B, continuous loops with hanging buttons were directly sutured to the tendon with eight simple sutures; group C, fixation was performed using the speed whip ripstop technique. Tensile tests with five cycles of preloading were performed at 50 N, held at 50 N for 1 min, and load-to-failure testing was conducted until rupture at 5 mm/min. The difference in the elongation and the maximum load-to-failure force were measured. The average elongation was significantly larger in group B (16.6 ± 2.2 mm) than in groups A (10.3 ± 2.4 mm) and C (10.0 ± 1.0 mm), (p < 0.001). The average load-to-failure force varied significantly between the three groups, 157.5 ± 33.4 N in group A, 253.4 ± 45.5 N in group B, and 337.7 ± 21.0 N in group C, (p < 0.001). Fixation using the speed whip ripstop technique to fix the suspensory button and soft-tissue transplant tendon resulted in minimal elongation and higher fixation strength. Simple devices that use this method have already been developed. Since it can be fixed using a relatively simple method, speed whip ripstop technique was shown to be advantageous for femoral fixation in ACL reconstruction using soft-tissue quadriceps tendon. The findings of this study could help surgeons reduce graft re-tear rates in ACL reconstruction using quadriceps tendons. N/A, laboratory control study.

A centrifugation-assisted peptide-mediated gene transfer (CAPT) method was recently developed as an efficient system for gene delivery into plant cells. However, the gene transfer efficiency of CAPT into plant cells was not entirely satisfactory for detecting transient expression of a transgene driven into mitochondria. Here, we report a new gene delivery system using a method called particle bombardment-assisted peptide-mediated gene transfer (PBPT). We investigated various parameters of the PBPT method to increase transient gene expression efficiency in Brassica campestris. The optimal conditions for PBPT were a single bombardment with gold particles coated with a DNA‒peptide complex (6 µg of DNA and 2 µg of peptide) at an acceleration pressure of 5 kg/cm2 and a target distance of 12.5 cm. Moreover, bombardment under the optimal conditions successfully transferred the transgene into the cells of other plant species, namely B. juncea and tomato. Thus, we developed a PBPT method for highly efficient delivery of a DNA‒peptide complex into plant mitochondria.

and the highest levels of alpine sports.The data was later linked to the database from the main Swedish insurance company of injuries for organized licensed and elite athletes, for additional injury information in future studies .Professional athletes, 15-40 years of age, who sustained an anterior cruciate ligament (ACL) injury and later underwent ACL-R during seasons 2005-2020 while playing in the two highest divisions in team sports or participating in official International Ski and Snowboard Federations were included.Outcomes were evaluated based on athletes sex, age, and division.The IR of ACL-R was calculated as injuries per 1000 athlete events (AE) and as injuries per 100000 athlete-seasons .Results Preliminary results identified a total of 1014 ACL-R in 932 athletes during the study period.Female basketball athletes had 5.6 times higher IR of ACL-R than male basketball athletes (IR 1.238 vs 0.221 per 1000 AE, incidence rate ratio [IRR] 5.595, 95% CI 3.370-9.289,p<0.001).In soccer, handball, floorball, and alpine sports the IR of ACL-R per 1000 AE was 2 to 3 times higher for females than for males.In professional ice hockey however, there was no significant difference in the IR of ACL-R between females and males (IR 0.080 vs 0.081 per 1000 AE, IRR 0.982, 95% CI 0.388-2.485,p¼0.844).The IR of ACL-R per 1000 AE in soccer was significantly higher compared to floorball, ice hockey, and alpine sports in both females and males.There was a significant higher IR of ACL-R in female handball athletes compared to female soccer athletes (IR 1.705 vs 1.161 per 1000 AE, IRR 1.469, 95% CI 1.163-1.857,p¼0.001).Conclusion This is the first nationwide study looking at the total IR of ACL-R in six different kneestrenuous sports during a same study period.The IR of ACL-R per 1000 AE in handball, soccer, basketball, floorball, and alpine sports were significantly higher in female athletes compared to male athletes.However, there was no significant difference in IR of ACL-R per 1000 AE in elite ice hockey between females and males.It seems necessary to continue to study and understand the IR of ACL-R in different sports to improve preventive measures for ACL injuries in the right sports and in the right individuals.

Background: The purpose of this study was to investigate the effect of growth on the ultra -structural characteristics of the quadriceps tendon (QT).Methods: Eighteen included patients were classified into three groups based on age and epiphyseal plate condition: the 'immature group' consisted of patients with open epiphy-seal plates (11.5 +/- 1.6 years old; mean +/- standard deviation), the 'young group' consisted of patients aged <20 years with closed epiphyseal plates (15.8 +/- 1.0 years), and the 'adult group' consisted of all patients aged >20 years (29.8 +/- 11.3 years) irrespective of epiphyseal plate condition. Tendon tissue samples were used for ultrastructural analysis by transmis-sion electron microscopy. Minimum collagen fibril diameters were measured from the cross sections of collagen fibril images using Image J software. The average number of col-lagen fibers per sample was 797 +/- 109, and the average collagen fibril diameter of each sample was compared using one-way analysis of variance.Results: The mean collagen fibril diameter was 89.7 +/- 14.4 nm in the immature group, 94. 8 +/- 16.4 nm in the young group, and 107.2 +/- 12.1 nm in the adult group, with significant differences between the immature and adult groups, and between the young and adult groups (P = 0.001 and P = 0.021, respectively); however, no significant differences were observed between the immature and young adult groups (P = 0.49).Conclusions: The collagen fibril diameter of the QT was found to have increased with growth. The study provided insights into graft selection. (c) 2023 Elsevier B.V. All rights reserved.

Background: The training environment for handball, particularly for young athletes, was affected by the COVID-19 pandemic in 2019 and 2020. Objectives: This study aimed to investigate the training sessions, injury incidence, and injury prevention program participation of youth handball teams during the COVID-19 pandemic and assess the barriers and factors influencing the motivation to perform such programs. Methods: This retrospective questionnaire-based cohort study included participants in the national handball championship in Japan in March 2021. The respondents included 48 coaches and 745 players from 66 teams. The coaches were asked questions about changes in the training time and intensity during the pandemic. The players were asked questions about barriers and motivational factors for performing the prevention exercises. Results: We found that 66.7% of the teams reduced their training time during the pandemic, while 45.8% reduced their training intensity. Owing to the COVID-19 pandemic, 91.7% of all teams experienced game cancellations, and player contact decreased in 33.3% of the teams. The main reason for not performing these exercises was a lack of knowledge on how to perform them correctly, as reported by 52.1% of the respondents. The main motivational factors were handball movement-related exercises (51.7%) and improved physical fitness (32.7%). Conclusions: The COVID-19 pandemic influenced the training sessions of Japanese youth handball teams in many ways. Education on correctly performing injury prevention program exercises is a key factor in maximizing the adoption of such programs. In addition, injury prevention exercises must be handball-specific to ensure that players are motivated to keep performing such exercises.

The foot exercises “rock-paper-scissors” and “towel gathering” are widely used in patients with lower limb disorders; however, there are no detailed reports on muscle activity during such training. We quantitatively evaluated the difference in skeletal muscle activity between the two exercises using positron emission tomography. Eight university student athletes were included. Four participants each were assigned to the foot rock-paper-scissors and towel gathering groups. Participants in each group underwent continuous training for 15 min, and received an intravenous injection of 18F-fluorodeoxyglucose. After retraining for 15 min, participants rested for 45 min. Regions of interest were defined in 25 muscles. The standardized uptake value (SUV) in the trained limb was compared with that in the non-trained control limb. SUVs increased in four skeletal muscles (tibialis anterior, peroneus brevis, extensor hallucis brevis, and abductor hallucis) in the rock-paper-scissors group, and in four muscles (flexor digitorum longus, extensor hallucis brevis, extensor digitorum brevis, and quadratus plantae) in the towel gathering group. Thus, foot rock-paper-scissors and towel gathering involved skeletal muscles related to the medial longitudinal arch and toe grip strength, respectively. Given that the two exercises target different skeletal muscles, they should be taught and implemented according to their respective purposes.