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Background: Ruptures of the anterior cruciate ligament (ACL) are common injuries. Reconstruction using autologous grafts is recommended to prevent further damage and functional impairment. Grafts are usually prepared with stabilizing sutures. The aim of this study was to evaluate if a 4-strand semitendinosus autograft preparation technique is non-inferior to conventional preparation techniques with regard to maximum tensile strength threshold. Methods: Fresh porcine flexor tendons were used as specimens in this study. Four different preparation techniques for quadruple-folded tendons were compared. Group 1 three suture FiberWire® (n = 20) and Group 2 one suture FiberWire® (n = 20) using Krakow stitches, Group 3 (n = 10) using SPEEDTRAP® and piercing the autograft and 4 (n = 9) using SPEEDTRAP® without piercing the autograft for preparation. Biomechanical tensile testing included 50 sinusoidal cycles of preloading between 50 and 150 N at 1 Hz and load-to-failure was measured at 20 mm/min. Results: Failure at the maximum load occurred at the filament for all samples, whereas failure of the suture/tendon interface was not observed. Load-to-failure was significantly higher in Group 1 (711 ± 91 N) than in all other groups. When comparing groups 2–4 load-to-failure was significantly higher in Group 2 (347 ± 24 N) than in Group 3 (258 ± 25 N, p < 0.02) but not than in Group 4 (325 ± 26N). Conclusion: In all 4 Groups the load to failure was higher than the maximum tension force on the construct that will be applied by hand (182N). Therefore, the needleless preparation technique seems to be a valuable alternative to conventional techniques for the insertion of the graft into the joint during joint-near tibial fixation technique. [ABSTRACT FROM AUTHOR]

Background: The use of a tourniquet is common during anterior cruciate ligament (ACL) reconstruction, offering convenience for the surgical procedure. However, the potential adverse effects of tourniquet use have gained increasing attention from clinical researchers. We conducted this systematic review and meta-analysis to compare the clinical outcomes of tourniquet application versus non-tourniquet approach during arthroscopic ACL reconstruction. Methods: A comprehensive search of PubMed, Web of Science, Embase, and Cochrane Library databases, was performed through March 2023 to identify controlled clinical trials. The main outcomes assessed included post-operative drain output, post-operative pain using a visual analogue scale (VAS), operation time, calf girth, and thigh girth. A random-effects meta-analysis was performed to account for heterogeneity, with weighted mean difference (WMD) and 95% confidence intervals (CI) used as pooled estimates for clinical outcomes. Results: Of the nine potentially related studies, seven eligible studies (sufficient quantitative data) were included in the meta-analysis. Postoperative drain output in the tourniquet group was on average 100 ml higher than in the non-tourniquet group (95% CI: 36 to 168). Pain, measured by the VAS at 24 h postoperatively, was 0.42 points higher in the tourniquet group (95% CI: 0.08 to 0.76), with the increase persisting at 48 h, averaging 0.40 points (95% CI: 0.12 to 0.69). Thigh girth in the tourniquet group was reduced by 1.8 cm (95% CI: -2.7 to -0.94). No significant differences were observed for calf girth and the operation time. Conclusion: Our meta-analysis indicates that tourniquet use during arthroscopic ACL reconstruction is associated with higher pain levels, increased postoperative drain output, and reduced thigh girth. However, performing the surgery without a tourniquet does not significantly extend the operation time. Trial registration: The protocol was registered in the International Prospective Register of Systematic Reviews, PROSPERO (CRD42023417604). [ABSTRACT FROM AUTHOR]

Background: The optimal treatment for anterior cruciate ligament (ACL) injuries with early-stage symptomless osteoarthritis (OA) remains unclear. This study aimed to compare the clinical outcomes of ACL reconstruction (ACLR) in patients with ACL injury in the presence and absence of early-stage symptomless OA. Methods: Medical records of patients with early-stage symptomless OA who sustained ACL injury and underwent ACLR from January 2018 to December 2020 at a single institution were retrospectively reviewed. Radiography and magnetic resonance imaging were performed preoperatively to identify ACL injury and OA. Patients with ACL injury and early-stage symptomless OA (combined group, n = 14) were matched at a 1:2 ratio with patients with ACL injury (isolated group, n = 32). Data on demographic characteristics, pain and functional outcomes (visual analogue scale, Tegner, Lysholm, and International Knee Documentation Committee scores and range of motion), and imaging outcomes were collected. Complications were recorded, and outcomes were compared between the groups. Results: Forty-six patients (26 males, 20 females) were included in this study, among whom 14 had ACL injury and early-stage symptomless OA, whereas 32 sustained isolated ACL injury (average follow-up duration: 3.4 ± 1.0 years). At the final follow-up, pain and functional outcomes similar to those in patients with isolated ACL-deficient knees were achieved in the combined group; acute-stage ACLR resulted in significantly better outcomes (p < 0.05). No significant radiographic progression of OA or complications were observed. Conclusions: Knee function in patients with ACL injuries and early-stage symptomless OA who underwent ACLR was the same as that in patients with isolated ACL-deficient knees. Furthermore, ACLR had a beneficial effect on knee outcomes. The subgroup analysis revealed that acute-stage ACLR could lead to better outcomes in patients with ACL injuries and early-stage symptomless OA. [ABSTRACT FROM AUTHOR]

Background: The literature does not clearly convey the relationship between eminential morphometry and non-contact anterior cruciate ligament (ACL) ruptures. This study attempts to reveal whether there is a relationship between non-contact ACL ruptures and eminential morphometry. Methods: Knee magnetic resonance images (MRIs) taken for the various indications between January 2022 and June 2023 were retrospectively scanned. The patients were categorized into 2 groups: those with an ACL rupture and those with an intact ACL. For each patient, eminential angle 1, eminential angle 2, medial eminential height, lateral eminential height, total eminential height, eminential width, and the ratio of tibial plateau width and eminential width to the tibial plateau width were measured by 2 different orthopedists. Patients whose MRIs were used for measurement were evaluated and grouped according to their age, sex, and injury side. Results: In total, 400 MRIs of 400 patients were included in the study. While 200 patients had an ACL rupture, 200 had an intact ACL. The total eminential height in the ACL rupture group was measured at 16.1 ± 2.6 mm and 15.5 ± 2.7 mm (p = 0.035) in the ACL intact group. Eminental width in the ACL rupture group was measured at 12.1 ± 1.9 mm and 13.0 ± 2.0 mm in the ACL intact group (p = 0.0001). The tibial plateau width was 75.4 ± 15.7 mm in the ACL rupture group and 73.6 ± 5.8 mm in the ACL intact group (p = 0.002). According to the logistic regression analysis, the p-value for males was 0.0001, and for eminential width, the p-value was 0.0001. Conclusions: A significant difference was found between the ACL rupture and the ACL intact groups regarding eminential height, eminential width, and tibial plateau width parameters. Being male and having a low eminential width were identified as independent risk factors for non-contact ACL. Trial registration: Not applicable. [ABSTRACT FROM AUTHOR]

Abstract Background The use of a tourniquet is common during anterior cruciate ligament (ACL) reconstruction, offering convenience for the surgical procedure. However, the potential adverse effects of tourniquet use have gained increasing attention from clinical researchers. We conducted this systematic review and meta-analysis to compare the clinical outcomes of tourniquet application versus non-tourniquet approach during arthroscopic ACL reconstruction. Methods A comprehensive search of PubMed, Web of Science, Embase, and Cochrane Library databases, was performed through March 2023 to identify controlled clinical trials. The main outcomes assessed included post-operative drain output, post-operative pain using a visual analogue scale (VAS), operation time, calf girth, and thigh girth. A random-effects meta-analysis was performed to account for heterogeneity, with weighted mean difference (WMD) and 95% confidence intervals (CI) used as pooled estimates for clinical outcomes. Results Of the nine potentially related studies, seven eligible studies (sufficient quantitative data) were included in the meta-analysis. Postoperative drain output in the tourniquet group was on average 100 ml higher than in the non-tourniquet group (95% CI: 36 to 168). Pain, measured by the VAS at 24 h postoperatively, was 0.42 points higher in the tourniquet group (95% CI: 0.08 to 0.76), with the increase persisting at 48 h, averaging 0.40 points (95% CI: 0.12 to 0.69). Thigh girth in the tourniquet group was reduced by 1.8 cm (95% CI: -2.7 to -0.94). No significant differences were observed for calf girth and the operation time. Conclusion Our meta-analysis indicates that tourniquet use during arthroscopic ACL reconstruction is associated with higher pain levels, increased postoperative drain output, and reduced thigh girth. However, performing the surgery without a tourniquet does not significantly extend the operation time. Trial registration The protocol was registered in the International Prospective Register of Systematic Reviews, PROSPERO (CRD42023417604).

Abstract Background The optimal treatment for anterior cruciate ligament (ACL) injuries with early-stage symptomless osteoarthritis (OA) remains unclear. This study aimed to compare the clinical outcomes of ACL reconstruction (ACLR) in patients with ACL injury in the presence and absence of early-stage symptomless OA. Methods Medical records of patients with early-stage symptomless OA who sustained ACL injury and underwent ACLR from January 2018 to December 2020 at a single institution were retrospectively reviewed. Radiography and magnetic resonance imaging were performed preoperatively to identify ACL injury and OA. Patients with ACL injury and early-stage symptomless OA (combined group, n = 14) were matched at a 1:2 ratio with patients with ACL injury (isolated group, n = 32). Data on demographic characteristics, pain and functional outcomes (visual analogue scale, Tegner, Lysholm, and International Knee Documentation Committee scores and range of motion), and imaging outcomes were collected. Complications were recorded, and outcomes were compared between the groups. Results Forty-six patients (26 males, 20 females) were included in this study, among whom 14 had ACL injury and early-stage symptomless OA, whereas 32 sustained isolated ACL injury (average follow-up duration: 3.4 ± 1.0 years). At the final follow-up, pain and functional outcomes similar to those in patients with isolated ACL-deficient knees were achieved in the combined group; acute-stage ACLR resulted in significantly better outcomes (p

Abstract Background The desire to return to sports (RTS) and return to performance at preinjury level (RTSP) is a common motivator for athletes undergoing anterior cruciate ligament (ACL) reconstructive surgery. However, for non-elite athletes little is known about the patient and surgical variables influencing RTS/RTSP. Purpose was to determine which patient or surgical variables had an effect on RTS/RTSP in non-elite athletes. We also analyzed whether patients that RTS and RTSP have more confidence in the knee and less difficulty pivoting. Methods A single-centre retrospective cohort study. All patients who had undergone primary hamstring ACL reconstruction within a 5-year period were included. Patients were asked about their pre- and postoperative sports participation using the Tegner Activity Score (TAS) as well as about their RTS/RTSP. Confidence in the knee and difficulty with pivoting were asked about. To determine the potential adverse effect of patient variables at the time of surgery (sex, age, height, weight, TAS preop) and surgical variables (graft diameter, surgical technique, concomitant injury) influencing RTS/RTSP, univariate and multivariate logistic regression analysis were used. Results 370 ACL reconstructions were included. Average follow-up was 4.6 years (SD 1.4). RTS rate was 65% and RTSP 43%. Median preinjury TAS was 7 (Q1:6, Q3:8)), postoperative 6 (Q1:4, Q3:7). Multivariate analysis showed that women were more likely to RTS (OR 2.40, 1.16–4.97). A lower preinjury TAS (OR 0.80, 0.67–0.95) resulted in higher RTSP levels. None of the surgical variables had a significant influence on RTS or RTSP. Patients who returned to sports or to preinjury-level performance displayed significantly more confidence in the operated knee and less difficulty pivoting than non-returning patients. Conclusion Our study shows that 65% of non-elite athletes with an ACL reconstruction returned to sports, 43% at preinjury level. Women were over twice more likely to RTS than men. Preinjury TAS significantly influences RTSP, with a lower preinjury TAS leading to a higher percentage of RTSP. Patients returning to both scored better in their self-reported confidence in the knee and difficulty pivoting than non-returning patients. Level of evidence Retrospective cohort III.

Abstract Background The positioning error of femoral tunnel was the key factor leading to the failure of anterior cruciate ligament (ACL) reconstruction. This study aimed to propose a new femoral tunnel classification to guide revision ACL reconstruction. Methods Totals of 150 patients with ACL reconstruction failure from 2017 to 2023 were enrolled in this retrospective study. According to the tunnel diameter, shape, posterior wall and the positioning relationship with the Lateral Intercondylar Ridge on the three-dimensional CT imaging, we divided the femoral tunnels into four types: Type I off-target type, Type II straddled type, Type III anatomical type, and Type IV irregular type. Finally, explored the inter-observer reliability within two groups of doctors (Group A, 12 high seniorities; Group B, 12 low seniorities), and evaluated the intra-observer reliability within 6 doctors after two months. Clinical evaluation was performed using the Lysholm score, Tenger activity score, Pivot Shift and anterior knee laxity measurements. Results Among 150 cases of femoral tunnel three-dimensional CT reconstructed imaging, 144 cases were successfully included in the classification system, and 6 cases were confirmed as uncertain type. We measured the Kappa (κ) coefficient of group A was significantly higher than that of group B (κ 0.72 VS 0.68), and the κ coefficient of group A was still higher than group B (κ 0.69 VS 0.62) after further dividing Type III anatomical type into three subtypes. In addition, the κ coefficients of intra-observer reliability were all exceeded 0.73. Clinical follow-up showed that 9 patients had good knee joint motor function and stability after operation. Conclusion The new femoral tunnel classification was reliable and had clinical guiding significance based on three-dimensional CT imaging. Level of evidence Level III.

Background: The positioning error of femoral tunnel was the key factor leading to the failure of anterior cruciate ligament (ACL) reconstruction. This study aimed to propose a new femoral tunnel classification to guide revision ACL reconstruction. Methods: Totals of 150 patients with ACL reconstruction failure from 2017 to 2023 were enrolled in this retrospective study. According to the tunnel diameter, shape, posterior wall and the positioning relationship with the Lateral Intercondylar Ridge on the three-dimensional CT imaging, we divided the femoral tunnels into four types: Type I off-target type, Type II straddled type, Type III anatomical type, and Type IV irregular type. Finally, explored the inter-observer reliability within two groups of doctors (Group A, 12 high seniorities; Group B, 12 low seniorities), and evaluated the intra-observer reliability within 6 doctors after two months. Clinical evaluation was performed using the Lysholm score, Tenger activity score, Pivot Shift and anterior knee laxity measurements. Results: Among 150 cases of femoral tunnel three-dimensional CT reconstructed imaging, 144 cases were successfully included in the classification system, and 6 cases were confirmed as uncertain type. We measured the Kappa (κ) coefficient of group A was significantly higher than that of group B (κ 0.72 VS 0.68), and the κ coefficient of group A was still higher than group B (κ 0.69 VS 0.62) after further dividing Type III anatomical type into three subtypes. In addition, the κ coefficients of intra-observer reliability were all exceeded 0.73. Clinical follow-up showed that 9 patients had good knee joint motor function and stability after operation. Conclusion: The new femoral tunnel classification was reliable and had clinical guiding significance based on three-dimensional CT imaging. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Background: The desire to return to sports (RTS) and return to performance at preinjury level (RTSP) is a common motivator for athletes undergoing anterior cruciate ligament (ACL) reconstructive surgery. However, for non-elite athletes little is known about the patient and surgical variables influencing RTS/RTSP. Purpose was to determine which patient or surgical variables had an effect on RTS/RTSP in non-elite athletes. We also analyzed whether patients that RTS and RTSP have more confidence in the knee and less difficulty pivoting. Methods: A single-centre retrospective cohort study. All patients who had undergone primary hamstring ACL reconstruction within a 5-year period were included. Patients were asked about their pre- and postoperative sports participation using the Tegner Activity Score (TAS) as well as about their RTS/RTSP. Confidence in the knee and difficulty with pivoting were asked about. To determine the potential adverse effect of patient variables at the time of surgery (sex, age, height, weight, TAS preop) and surgical variables (graft diameter, surgical technique, concomitant injury) influencing RTS/RTSP, univariate and multivariate logistic regression analysis were used. Results: 370 ACL reconstructions were included. Average follow-up was 4.6 years (SD 1.4). RTS rate was 65% and RTSP 43%. Median preinjury TAS was 7 (Q1:6, Q3:8)), postoperative 6 (Q1:4, Q3:7). Multivariate analysis showed that women were more likely to RTS (OR 2.40, 1.16–4.97). A lower preinjury TAS (OR 0.80, 0.67–0.95) resulted in higher RTSP levels. None of the surgical variables had a significant influence on RTS or RTSP. Patients who returned to sports or to preinjury-level performance displayed significantly more confidence in the operated knee and less difficulty pivoting than non-returning patients. Conclusion: Our study shows that 65% of non-elite athletes with an ACL reconstruction returned to sports, 43% at preinjury level. Women were over twice more likely to RTS than men. Preinjury TAS significantly influences RTSP, with a lower preinjury TAS leading to a higher percentage of RTSP. Patients returning to both scored better in their self-reported confidence in the knee and difficulty pivoting than non-returning patients. Level of evidence: Retrospective cohort III. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) graft failure is influenced by factors such as meniscal tears and tibial plateau slope. Combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction has reduced failure rates; however, its efficacy in high-risk patients remains unclear. This study hypothesized that combined ACL and ALL reconstruction would yield similar clinical outcomes in patients with varying risks of ACL failure. Patients and methods: A total of 76 patients who underwent primary single-bundle ACL reconstruction combined with ALL reconstruction between June 2018 and June 2021 were included. The medial tibial slope (MTS), lateral tibial slope (LTS), and anterior tibial translation (ATT) were measured using magnetic resonance imaging and plain radiography of the knee joint. The meniscal lesions were assessed during surgery. Preoperative clinical assessments and final follow-up were conducted using patient-reported outcome measurements (PROMs), including the International Knee Documentation Committee (IKDC) evaluation, Lysholm knee scoring scale, and Tegner Activity scale. PROMs were collected at least two years postoperatively. Results: The average follow-up was 32.5 ± 7.4 months. There were no significant differences in postoperative IKDC score, Lysholm score, or Tegner activity score between patients with or without medial meniscus injury (p = 0.155, 0.914, and 0.042, respectively), with or without lateral meniscus injury (p = 0.737, 0.569, and 0.942, respectively), medial tibial slope > 12° or ≤ 12° (p = 0.290, 0.496, and 0.988, respectively), or lateral tibial slope > 7.4° or ≤ 7.4° (p = 0.213, 0.625, and 0.922, respectively). No significant correlations were found between anterior tibial translation and postoperative IKDC (R = -0.058, p = 0.365), Lysholm (R = -0.017, p = 0.459), or Tegner activity scores (R = -0.147, p = 0.189). Conclusion: Our study demonstrates that single-bundle ACL reconstruction combined with ALL reconstruction provides reliable and comparable clinical outcomes in patients with high-risk factors for ACL graft failure, such as increased tibial slope or meniscal injury. Our results suggest that the indications for ALL reconstruction may be expanded to include patients with a high tibial slope or meniscal injury, because these factors have been shown to contribute to increased rotational instability and high rates of ACL graft failure. Future prospective randomized controlled trials with large patient cohorts and long follow-up periods are needed to validate these findings and establish clear guidelines for patient selection and surgical decision-making. Level of evidence: Level 3. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to investigate the initial stability of different screw placements in arthroscopic anterior cruciate ligament (ACL) tibial avulsion fracture fixation. Methods: A three-dimensional knee model at 90° flexion was utilized to simulate type III ACL tibial avulsion fracture and arthroscopic screw fixation through different portals, namely the central transpatellar tendon portal (CTP), anterolateral portal (ALP), anteromedial portal (AMP), lateral parapatellar portal (LPP), medial parapatellar portal (MPP), lateral suprapatellar portal (LSP), medial suprapatellar portal (MSP). A shear force of 450 N was applied to the finite element models at 30° flexion to simulate the failure condition. The displacement of the bony fragment and the volume of the bone above 25,000 µ-strain (damaged bone volume) were calculated around the screw path. Results: When the screw was implanted through CTP, the displacement of the bony fragment reached the maximum displacement which was 1.10 mm and the maximum damaged bone volume around the screw path was 148.70 mm3. On the other hand, the minimum displacement of the bony fragment was 0.45 mm when the screw was implanted through LSP and MSP. The minimum damaged bone volume was 14.54 mm3 around the screw path when the screw was implanted through MSP. Conclusion: Screws implanted through a higher medial portal generated less displacement of the bony fragment and a minimum detrimental strain around the screw path. The findings are clinically relevant as they provide biomechanical evidence on optimizing screw placement in arthroscopic ACL tibial avulsion fracture fixation. [ABSTRACT FROM AUTHOR]

Abstract Introduction Anterior cruciate ligament (ACL) ruptures are common injuries that typically affect young, physically active individuals and may require surgical reconstruction. Studies have shown that the long time success of ACL reconstruction depends on the surgical technique and the postoperative rehabilitation strategy. However, there is still no consensus on the content of rehabilitation programs. Hence, additional research is required to elucidate the significance of early weight-bearing in the rehabilitation process following ACL reconstruction. The aim of this article is to examine the impact of weight-bearing on the clinical results of ACL reconstruction. Materials and methods We retrospectively reviewed patient records who had undergone arthroscopic reconstruction using a semitendinosus-gracilis tendon graft for anterior cruciate ligament rupture between January 2018 and December 2020. The study included the data of 110 patients. The patients were split into two groups: Group 1 underwent early weight-bearing, while Group 2 followed a non-weight-bearing regimen for three weeks. We assessed the patients using the anterior drawer test, Lachman test, range of motion, Lysholm knee scale, Cincinnati scale, Tegner scale, International Knee Documentation Committee (IKDC) form and clinical records. Analytical tests were conducted to compare the results. Results The complication rates did not show a significant difference between the groups. Group 1 had higher frequencies of positive anterior drawer and Lachman tests. The Lysholm and Cincinnati knee scores of patients in Group 1 were notably lower than those of patients in Group 2. Additionally, the Tegner activity scores and IKDC scores of patients in Group 1 were also meaningfully lower than those of patients in Group 2. In Group 1 patients, there was no notable relationship observed between body mass index (BMI) and the results of the anterior drawer test (ADT) or Lachman test. However, patients with a BMI of 25 or higher in Group 1 showed a decrease in postoperative IKDC scores. In Group 2 patients, no significant relationship was identified between BMI and either the ADT or the Lachman test outcome. Conclusion Based on current literature and current rehabilitation guidelines following ACL reconstruction, the decision to initiate early weight-bearing is based on a limited number of studies with low levels of evidence. In our study, we found that patients who followed a non-weight-bearing regimen for 3 weeks after surgery had better mid-term results than those who were allowed to bear weight early. It appears that further prospective studies on this topic are needed to update rehabilitation guidelines in the next.

Abstract Background An isokinetic moment curve (IMC) pattern-damaged structure prediction model may be of considerable value in assisting the diagnosis of knee injuries in clinical scenarios. This study aimed to explore the association between irregular IMC patterns and specific structural damages in the knee, including anterior cruciate ligament (ACL) rupture, meniscus (MS) injury, and patellofemoral joint (PFJ) lesions, and to develop an IMC pattern-damaged structure prediction model. Methods A total of 94 subjects were enrolled in this study and underwent isokinetic testing of the knee joint (5 consecutive flexion-extension movements within the range of motion of 90°-10°, 60°/s). Qualitative analysis of the IMCs for all subjects was completed by two blinded examiners. A multinomial logistic regression analysis was used to investigate whether a specific abnormal curve pattern was associated with specific knee structural injuries and to test the predictive effectiveness of IMC patterns for specific structural damage in the knee. Results The results of the multinomial logistic regression revealed a significant association between the irregular IMC patterns of the knee extensors and specific structural damages (“Valley” - ACL, PFJ, and ACL + MS, “Drop” - ACL, and ACL + MS, “Shaking” - ACL, MS, PFJ, and ACL + MS). The accuracy and Macro-averaged F1 score of the predicting model were 56.1% and 0.426, respectively. Conclusion The associations between irregular IMC patterns and specific knee structural injuries were identified. However, the accuracy and Macro-averaged F1 score of the established predictive model indicated its relatively low predictive efficacy. For the development of a more accurate predictive model, it may be essential to incorporate angle-specific and/or speed-specific analyses of qualitative and quantitative data in isokinetic testing. Furthermore, the utilization of artificial intelligence image recognition technology may prove beneficial for analyzing large datasets in the future.

Background: The present study evaluated whether the lack of histone deacetylase 4 (HDAC4) increases endoplasmic reticulum stress-induced chondrocyte apoptosis by releasing activating transcription factor 4 (ATF4) in human osteoarthritis (OA) cartilage degeneration. Methods: Articular cartilage from the tibial plateau was obtained from patients with OA during total knee replacement. Cartilage extracted from severely damaged regions was classified as degraded cartilage, and cartilage extracted from a relatively smooth region was classified as preserved cartilage. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining was used to detect chondrocyte apoptosis. HDAC4, ATF4, and C/EBP homologous protein (CHOP) expression levels were measured using immunohistochemistry staining and real-time quantitative PCR. Chondrocytes were transfected with HDAC4 or HDAC4 siRNA for 24 h and stimulated with 300 µM H2O2 for 12 h. The chondrocyte apoptosis was measured using flow cytometry. ATF4, CHOP, and caspase 12 expression levels were measured using real-time quantitative PCR and western blotting. Male Sprague-Dawley rats (n = 15) were randomly divided into three groups and transduced with different vectors: ACLT + Ad-GFP, ACLT + Ad-HDAC4-GFP, and sham + Ad-GFP. All rats received intra-articular injections 48 h after the operation and every three weeks thereafter. Cartilage damage was assessed using Safranin O staining and quantified using the Osteoarthritis Research Society International score. ATF4, CHOP, and collagen II expression were detected using immunohistochemistry, and chondrocyte apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Results: The chondrocyte apoptosis was higher in degraded cartilage than in preserved cartilage. HDAC4 expression was lower in degraded cartilage than in preserved cartilage. ATF4 and CHOP expression was increased in degraded cartilage. Upregulation of HDAC4 in chondrocytes decreased the expression of ATF4, while the expression of ATF4 was increased after downregulation of HDAC4. Upregulation of HDAC4 decreased the chondrocyte apoptosis under endoplasmic reticulum stress, and chondrocyte apoptosis was increased after downregulation of HDAC4. In a rat anterior cruciate ligament transection OA model, adenovirus-mediated transduction of HDAC4 was administered by intra-articular injection. We detected a stronger Safranin O staining with lower Osteoarthritis Research Society International scores, lower ATF4 and CHOP production, stronger collagen II expression, and lower chondrocyte apoptosis in rats treated with Ad-HDAC4. Conclusion: The lack of HDAC4 expression partially contributes to increased ATF4, CHOP, and endoplasmic reticulum stress-induced chondrocyte apoptosis in OA pathogenesis. HDAC4 attenuates cartilage damage by repressing ATF4-CHOP signaling-induced chondrocyte apoptosis in a rat model of OA. [ABSTRACT FROM AUTHOR]

Introduction: Anterior cruciate ligament (ACL) ruptures are common injuries that typically affect young, physically active individuals and may require surgical reconstruction. Studies have shown that the long time success of ACL reconstruction depends on the surgical technique and the postoperative rehabilitation strategy. However, there is still no consensus on the content of rehabilitation programs. Hence, additional research is required to elucidate the significance of early weight-bearing in the rehabilitation process following ACL reconstruction. The aim of this article is to examine the impact of weight-bearing on the clinical results of ACL reconstruction. Materials and methods: We retrospectively reviewed patient records who had undergone arthroscopic reconstruction using a semitendinosus-gracilis tendon graft for anterior cruciate ligament rupture between January 2018 and December 2020. The study included the data of 110 patients. The patients were split into two groups: Group 1 underwent early weight-bearing, while Group 2 followed a non-weight-bearing regimen for three weeks. We assessed the patients using the anterior drawer test, Lachman test, range of motion, Lysholm knee scale, Cincinnati scale, Tegner scale, International Knee Documentation Committee (IKDC) form and clinical records. Analytical tests were conducted to compare the results. Results: The complication rates did not show a significant difference between the groups. Group 1 had higher frequencies of positive anterior drawer and Lachman tests. The Lysholm and Cincinnati knee scores of patients in Group 1 were notably lower than those of patients in Group 2. Additionally, the Tegner activity scores and IKDC scores of patients in Group 1 were also meaningfully lower than those of patients in Group 2. In Group 1 patients, there was no notable relationship observed between body mass index (BMI) and the results of the anterior drawer test (ADT) or Lachman test. However, patients with a BMI of 25 or higher in Group 1 showed a decrease in postoperative IKDC scores. In Group 2 patients, no significant relationship was identified between BMI and either the ADT or the Lachman test outcome. Conclusion: Based on current literature and current rehabilitation guidelines following ACL reconstruction, the decision to initiate early weight-bearing is based on a limited number of studies with low levels of evidence. In our study, we found that patients who followed a non-weight-bearing regimen for 3 weeks after surgery had better mid-term results than those who were allowed to bear weight early. It appears that further prospective studies on this topic are needed to update rehabilitation guidelines in the next. [ABSTRACT FROM AUTHOR]

Background: An isokinetic moment curve (IMC) pattern-damaged structure prediction model may be of considerable value in assisting the diagnosis of knee injuries in clinical scenarios. This study aimed to explore the association between irregular IMC patterns and specific structural damages in the knee, including anterior cruciate ligament (ACL) rupture, meniscus (MS) injury, and patellofemoral joint (PFJ) lesions, and to develop an IMC pattern-damaged structure prediction model. Methods: A total of 94 subjects were enrolled in this study and underwent isokinetic testing of the knee joint (5 consecutive flexion-extension movements within the range of motion of 90°-10°, 60°/s). Qualitative analysis of the IMCs for all subjects was completed by two blinded examiners. A multinomial logistic regression analysis was used to investigate whether a specific abnormal curve pattern was associated with specific knee structural injuries and to test the predictive effectiveness of IMC patterns for specific structural damage in the knee. Results: The results of the multinomial logistic regression revealed a significant association between the irregular IMC patterns of the knee extensors and specific structural damages ("Valley" - ACL, PFJ, and ACL + MS, "Drop" - ACL, and ACL + MS, "Shaking" - ACL, MS, PFJ, and ACL + MS). The accuracy and Macro-averaged F1 score of the predicting model were 56.1% and 0.426, respectively. Conclusion: The associations between irregular IMC patterns and specific knee structural injuries were identified. However, the accuracy and Macro-averaged F1 score of the established predictive model indicated its relatively low predictive efficacy. For the development of a more accurate predictive model, it may be essential to incorporate angle-specific and/or speed-specific analyses of qualitative and quantitative data in isokinetic testing. Furthermore, the utilization of artificial intelligence image recognition technology may prove beneficial for analyzing large datasets in the future. [ABSTRACT FROM AUTHOR]

Abstract Objective Evaluation of the accuracy and effectiveness of 3D printed guides to assist femoral tunnel preparation in individualised reconstruction of the anterior cruciate ligament. Methods Sixty patients who attended the Affiliated Hospital of Binzhou Medical College for autologous hamstring single bundle reconstruction of the anterior cruciate ligament from October 2018 to October 2020 were selected and randomly divided into two groups, including 31 cases in the 3D printing group (14 males and 17 females, mean age 41.94 ± 10.15 years) and 29 cases in the control group (13 males and 16 females, mean age 37.76 ± 10.34 years). Patients in both groups were assessed for intraoperative femoral tunnel accuracy, the number of intraoperative positioning and the time taken to prepare the femoral tunnel, the length of the anteromedial approach incision, the pre-planned bone tunnel length and intraoperative bone tunnel length in the 3D printed group, IKDC score and Lysholm score preoperatively and at 3, 6 and 12 months postoperatively, the Lachman、pivot-shift test preoperatively and at 6 months postoperatively, gait analysis to assess internal and external rotation in flexion of the knee at 12 months postoperatively and postoperative complications in both groups. Results There was no statistical difference in functional knee scores and anteromedial approach incision length between the 3D printed and control groups (p > 0.05), while there was a statistical difference in the accuracy of tunnel positioning, the time taken to prepare the femoral bone tunnel and the degree of external rotation of the knee in flexion between the two groups (p 0.05). Complications: One case in the 3D printing group developed intermuscular vein thrombosis in the affected lower limb after surgery, which disappeared after treatment, while three cases in the control group developed intermuscular vein thrombosis in the affected lower limb. No complications such as bone tunnel rupture, deep vein thrombosis in the lower limb and infection occurred in either group. Conclusion 3D printed guides assisted with individualized ACL reconstruction may improve the accuracy of femoral tunnel positioning, which is safe and effective, while reducing the operative time and the number of intraoperative positioning, without increasing the length of incision, and may obtain higher functional scores and rotational stability of the knee joint, which is in line with the concept of individualized ACL reconstruction.

Abstract Background Anterior cruciate ligament (ACL) rupture is a common orthopedic injury, occurring in roughly 68.6 per 100,000 persons annually, with the primary treatment option being ACL reconstruction. However, debate remains about the appropriate graft type for restoring the native biomechanical properties of the knee. Furthermore, plastic graft elongation may promote increased knee laxity and instability without rupture. This study aims to investigate the plastic properties of common ACL-R graft options. Methods Patellar tendon (PT), hamstring tendon (HT), and quadriceps tendon (QT) grafts were harvested from 11 cadaveric knees (6 male and 5 female) with a mean age of 71(range 55–81). All grafts were mechanically tested under uniaxial tension until failure to determine each graft’s elastic and plastic biomechanical properties. Results Mechanically, the QT graft was the weakest, exhibiting the lowest failure force and the lowest failure stress (QT QT, p = 0.0002) and Young’s modulus (PT > QT, p = 0.001; PT > HT, p = 0.041). The HT graft had the highest plastic elongation at 4.01 ± 1.32 mm (HT > PT, p = 0.002). The post-yield behavior of the HT tendon shows increased energy storage capabilities with the highest plastic energy storage (HT > QT, p = 0.012) and the highest toughness (HT > QT, p = 0.032). Conclusion Our study agrees with prior studies indicating that the failure load of all grafts is above the requirements for everyday activities. However, grafts may be susceptible to yielding before failure during daily activities. This may result in the eventual loss of functionality for the neo-ACL, resulting in increased knee laxity and instability.

Abstract Background There is no clear consensus regarding the superiority of a combined anterior cruciate ligament reconstruction (ACLR) with anterolateral ligament reconstruction (ALLR) versus an isolated ACLR. In this study, we compared the postoperative stability profile, complications, and patient-reported outcomes of these procedures. Methods Twenty-one patients with an anterior cruciate ligament (ACL) tear who were either treated by an isolated all-inside ACLR (n = 21) or a combined all-inside ACLR and ALLR (n = 20) were included. The outcomes were evaluated in the last follow-up and included the postoperative stability profile evaluated by the Lachman test, pivot shift test, and KT-1000 side-to-side difference, postoperative complications, and patient-reported outcomes evaluated by the International Knee Documentation Committee (IKDC) score and Lysholm knee scale. Results The baseline characteristics of the two groups were not significantly different. The residual Lachman and pivot shift were not significantly different between the two groups (P = 0.41 and P = 0.18, respectively). The mean KT-1000 side-to-side difference was 1.93 ± 1.9 mm in the isolated and 1.635 ± 0.91 mm in the combined group (P = 0.01). The mean improvement of the IKDC score was not significantly different between the isolated and combined groups (24.7 vs. 25.2, P = 0.28). The mean improvement of the Lysholm scale was not significantly different between the isolated and combined groups (33.5 vs. 34.1, P = 0.19). ACL re-rupture occurred in three patients of the isolated group and no patient of the combined group. Conclusion The outcomes of patients in the present study support performing a combined ALL and ACL reconstruction.

Background: Magnetic resonance imaging (MRI) and manual tests remain the standard for diagnosing anterior cruciate ligament (ACL) rupture. Furthermore, the passive knee displacement, also described as anterior tibial translation (ATT), is used in order to make decisions about surgery or to assess rehabilitation outcomes. Unfortunately, these manual tests are limited to passive situations, and their application to assess knee stability in loaded, weight-bearing positions are missing. Therefore, a new device with high-performance sensors and a new sensor setting was developed. The aim of this exploratory cross-sectional study was to assess the test-retest reliability of this new device in a first step and the concurrent validity in a second step. Methods: A total of 20 healthy volunteers were measured. Measurement consistency of the new device was assessed on the basis of reliability during Lachman test setting and in loaded position by artificial knee perturbation in a test-retest procedure. In a second step, the concurrent validity was evaluated with the Lachmeter® as a reference instrument. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), the minimal detectable change (MDC) and Bland-Altman analysis were evaluated to assess the quality criteria. Results: The measurements with the new device during the Lachman test provided a mean ATT of 5.46±2.22mm. The SEM ranged from 0.60 to 0.69mm resulting in an MDC between 1.67 and 1.93mm for the new device. In the loaded test situation, the mean ATT was 2.11±1.20mm, with test-retest reliability also showing good correlation (r>0.83). The comparison of the two measurement methods with an ICC of (r>0.89) showed good correlation, which also underlines the reasonable agreement of the Bland-Altman analysis. Conclusions: The evaluation of the test-retest reliability of the new device during the knee stability testing in passive situation as well as in a functional, loaded situation presented good reliability. In addition, the new device demonstrated good agreement with the reference device and therefore good validity. Furthermore, the quality criteria demonstrated the ability of the new device to detect the cut-off value (3-5mm) described in the literature for the diagnosis of ACL-deficient knees, which underlines the clinical relevance of this new device as a reliable and valid tool. [ABSTRACT FROM AUTHOR]

Abstract Background Augmentation of the biologic graft with nonabsorbable suture material during anterior cruciate ligament reconstruction (ACLR) is a relatively new technique to enhance its biomechanical properties and add additional support to the critical process of healing. We aimed to compare the short-term functional patient-reported outcome measures (PROMs) and complication rates of patients treated with either standard single-bundle four-strand hamstring ACLR or added suture augmentation (SA). Methods Patients undergoing arthroscopic ACLR between February 2015-January 2017 and in the standard ACLR group, and between February 2017-September 2019 in the SA-ACLR group operated by adding a no.5 FiberWire® (Arthrex, Naples, FL, USA) braided suture to the hamstring autograft, were retrospectively reviewed and the PROMs were compared. Patients were followed up for a 24-month period and PROMs were assessed by the International Knee Documentation Committee (IKDC) Subjective Knee Form and Tegner-Lysholm knee score. Patients’ demographic and clinical characteristics, and postoperative complications including graft retear requiring revision surgery, deep vein thrombois, and surgical site infection were recorded and analyzed. Results We included 79 patients with mean age of 31.6 ± 8.3 years in the standard ACLR group, and 90 patients with mean oge of 30.5 ± 7.6 in the SA-ACLR group. There was no statistically significant difference between the two groups in terms of age, sex, body mass index, and medical comorbidities. The values of the IKDC scores increased to 75.8 ± 18.9 in the standard ACLR group, and 85.6 ± 12.6 in the SA-ACLR group, 24 months after the operation (P < 0.05). The 24-month postoperative Tegner-Lysholm scores escalated to 79.3 ± 21.0 in the standard ACLR group and 91.0 ± 13.7 in the SA-ACLR group (P < 0.05). Four (5.1%) patients in the standard ACLR group and 4 (4.4%) in the SA-ACLR group experienced graft retear requiring revision surgery (P > 0.05). Incidence of surgical site infection and deep vein thrombosis showed no significant differences between the two groups, 24 months after ACLR. Conclusion SA-ACLR is associated with improved short-term functional PROMs compared to the standard hamstring ACLR. Although SA did not reduce the retear rate, and infection and DVT rates did not differ between study groups, superior improvement of PROMs in SA approach, leverages this method for ACLR.

Abstract Background An appropriate method for comparing knee function and activity level between patients with primary and revision anterior cruciate ligament reconstruction (ACLR) is to perform a matched-group analysis. The aim was to assess and compare knee function, knee-related quality of life and activity level between patients with revision ACLR and primary ACLR at a minimum of 5 years of follow-up. Methods Patients aged ≤ 40 years old who underwent revision ACLR between 2010 and 2015 and a matched control group (primary ACLR) (1:1) with age ± 2 years, year of ACLR, sex, and pre-injury sport and Tegner Activity Scale (TAS) were retrospectively identified in our clinic database. The preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) and surgical data were extracted and analyzed. Patients were mailed KOOS and EQ-5D questionnaires at a minimum of 5-years after revision ACLR. Study-specific questions about knee function, limitation in sport, satisfaction, and activity level according to the TAS (all scales of 1–10, 10 best) were also asked by telephone. Results Seventy-eight patients with a revision ACLR (mean age ± SD, 29.9 ± 6.0 years) matched with seventy-eight patients with a primary ACLR (30.2 ± 5.8 years) were included. The follow-up for the revision ACLR group was 7.0 ± 1.5 years and for the primary ACLR group 7.7 ± 1.6 years. The revision ACLR group reported poorer KOOS scores in all subscales (p

Abstract Background Little is known about knee mechanics and muscle control after augmented ACL repair. Our aim was to compare knee biomechanics and leg muscle activity during walking between the legs of patients 2 years after InternalBraceTM-augmented anterior cruciate ligament repair (ACL-IB) and between patients after ACL-IB and ACL reconstruction (ACL-R), and controls. Methods Twenty-nine ACL-IB, 27 sex- and age-matched ACL-R (hamstring tendon autograft) and 29 matched controls completed an instrumented gait analysis. Knee joint angles, moments, power, and leg muscle activity were compared between the involved and uninvolved leg in ACL-IB (paired t-tests), and between the involved legs in ACL patients and the non-dominant leg in controls (analysis of variance and posthoc Bonferroni tests) using statistical parametric mapping (SPM, P uninvolved) and maximum knee flexion moment during stance (-0.07Nm/kg, CI [-0.13;-0.00]; involved ACL-R). Compared to controls, ACL-IB (SPM: 0–3%GC, P = 0.015; 98–100%, P = 0.016; DP: -6.3 mm, CI [-11.7;-0.8]) and ACL-R (DP: -6.0 mm, CI [-11.4;-0.2]) had lower (maximum) anterior tibia position around heel strike. ACL-R also had lower maximum knee extension moment (DP: -0.13Nm/kg, CI [-0.23;-0.02]) and internal knee rotation moment (SPM: 34–41%GC, P

Abstract Background Different types of grafts can be used for anterior cruciate ligament reconstruction (ACLR). There is little published data regarding skeletally immature patients. The purpose of this systematic review was to assess the clinical outcomes and complications for different autograft types used in all-epiphyseal, transphyseal and partial epiphyseal/hybrid ACLR in skeletally immature children and adolescents. Methods PubMed, Embase and Cochrane databases were systematically searched for literature regarding ACLR using hamstrings, quadriceps or bone-patellar-tendon-bone (BPTB) autografts in skeletally immature patients. Studies were included if they examined at least one of the following outcomes: graft failure, return to sport(s), growth disturbance, arthrofibrosis or patient reported outcomes and had a minimum follow-up of 1 year. Case reports, conference abstracts and studies examining allografts and extra-articular or over-the-top ACL reconstruction techniques were excluded. Graft failure rates were pooled for each graft type using the quality effects model of MetaXL. A qualitative synthesis of secondary outcomes was performed. Results The database search identified 242 studies. In total 31 studies were included in this review, comprising of 1358 patients. Most patients (81%) were treated using hamstring autograft. The most common used surgical technique was transphyseal. The weighted, pooled failure rate for each graft type was 12% for hamstring tendon autografts, 8% for quadriceps tendon autografts and 6% for BPTB autografts. Confidence intervals were overlapping. The variability in time to graft failure was high. The qualitative analysis of the secondary outcomes showed similar results with good clinical outcomes and low complication rates across all graft types. Conclusions Based on this review it is not possible to determine a superior graft type for ACLR in skeletally immature. Of the included studies, the most common graft type used was the hamstring tendon. Overall, graft failure rates are low, and most studies show good clinical outcomes with high return to sports rates.

Background: Augmentation of the biologic graft with nonabsorbable suture material during anterior cruciate ligament reconstruction (ACLR) is a relatively new technique to enhance its biomechanical properties and add additional support to the critical process of healing. We aimed to compare the short-term functional patient-reported outcome measures (PROMs) and complication rates of patients treated with either standard single-bundle four-strand hamstring ACLR or added suture augmentation (SA). Methods: Patients undergoing arthroscopic ACLR between February 2015-January 2017 and in the standard ACLR group, and between February 2017-September 2019 in the SA-ACLR group operated by adding a no.5 FiberWire® (Arthrex, Naples, FL, USA) braided suture to the hamstring autograft, were retrospectively reviewed and the PROMs were compared. Patients were followed up for a 24-month period and PROMs were assessed by the International Knee Documentation Committee (IKDC) Subjective Knee Form and Tegner-Lysholm knee score. Patients' demographic and clinical characteristics, and postoperative complications including graft retear requiring revision surgery, deep vein thrombois, and surgical site infection were recorded and analyzed. Results: We included 79 patients with mean age of 31.6 ± 8.3 years in the standard ACLR group, and 90 patients with mean oge of 30.5 ± 7.6 in the SA-ACLR group. There was no statistically significant difference between the two groups in terms of age, sex, body mass index, and medical comorbidities. The values of the IKDC scores increased to 75.8 ± 18.9 in the standard ACLR group, and 85.6 ± 12.6 in the SA-ACLR group, 24 months after the operation (P < 0.05). The 24-month postoperative Tegner-Lysholm scores escalated to 79.3 ± 21.0 in the standard ACLR group and 91.0 ± 13.7 in the SA-ACLR group (P < 0.05). Four (5.1%) patients in the standard ACLR group and 4 (4.4%) in the SA-ACLR group experienced graft retear requiring revision surgery (P > 0.05). Incidence of surgical site infection and deep vein thrombosis showed no significant differences between the two groups, 24 months after ACLR. Conclusion: SA-ACLR is associated with improved short-term functional PROMs compared to the standard hamstring ACLR. Although SA did not reduce the retear rate, and infection and DVT rates did not differ between study groups, superior improvement of PROMs in SA approach, leverages this method for ACLR. [ABSTRACT FROM AUTHOR]

Background: Bicruciate-retaining (BCR) prosthesis has been introduced to recreate normal knee movement by preserving both the anterior and posterior cruciate ligaments. However, the use of BCR total knee arthroplasty (TKA) is still debatable because of several disappointing reports. We have been performing BCR TKAs with personalized alignment (PA). This study aimed to reveal the limb alignment and soft tissue balance of FA-BCR TKAs and compare the clinical outcomes of FA-BCR TKAs with those of unicompartmental knee arthroplasty (UKA). Methods: Fifty BCR TKAs and 58 UKAs were included in this study. The joint component gaps of BCR TKA were evaluated intraoperatively and the postoperative hip–knee–ankle (HKA) angle, medial proximal tibial angle (MPTA), and lateral distal femoral angle (LDFA) were measured using full-length standing radiography. The short-term clinical outcomes of BCR TKAs were compared with those of UKA using the scoring system of 2011 Knee Society Scoring (KSS) and the knee injury and osteoarthritis outcome score (KOOS) at an average of 2 years postoperatively (1-4yeras). Results: The coronal alignment values of PA-BCR TKA were as follows: HKA angle, 177.9° ± 2.3°; MPTA, 85.4° ± 1.9°; and LDFA, 87.5° ± 1.9°. The joint component gaps at flexion angles of 10°, 30°, 60°, and 90° were 11.1 ± 1.2, 10.9 ± 1.4, 10.7 ± 1.3, and 11.2 ± 1.4 mm for the medial compartment and 12.9 ± 1.5, 12.6 ± 1.8, 12.5 ± 1.8 and 12.5 ± 1.7 mm for the lateral compartment, respectively. The patient expectation score and maximum extension angle of PA-BCR TKA were significantly better than those of UKAs. Conclusions: The short-term clinical outcomes of PA-BCR TKA were comparable or a slightly superior to those of UKAs. [ABSTRACT FROM AUTHOR]

Background: Patients with anterior cruciate ligament (ACL) deficiency (ACLD) tend to have altered lower extremity dynamics. Little is known about the changes in dynamic function and activation during jogging in patients with ACLD. Methods: Twenty patients with an injured ACL before ACL reconstruction (ACLD group) and nine healthy male volunteers (control group) were recruited. Each volunteer repeated the jogging experiment five times. Based on the experimental data measured, a musculoskeletal multibody dynamics model was employed to simulate the tibiofemoral joint dynamics during jogging. Eighteen muscles were used for analysis. The obtained dynamics data were used for clustering and curve difference analysis. Results: The 18 muscles studied were divided into 3 categories. All the quadriceps, the soleus, the gastrocnemius, and the popliteus were classified as label 1. All the hamstrings were classified as label 2, and the sartorius muscles were classified as label 3. Among them, the classification of the short head of the biceps femoris was significantly different between the two groups (P < 0.001). The force curves of all 18 muscles and the between-group differences were studied according to clustered categories. Most muscle force in label 1 was approaching zero in the terminal stance phase, which was significantly lower than that in the control group (P < 0.05). The muscle force in label 2 had areas with significant differences in the stance phase. Muscle force in label 3 was significantly lower than that in the control group in the pre-swing phase. Conclusions: This study showed that there are various changes of muscle function and activation in patients with ACLD. Through clustering and curve analysis, the joint reactions and changes of different muscle forces in the gait cycle between the ACLD and control groups could be further clarified. [ABSTRACT FROM AUTHOR]

Background: An appropriate method for comparing knee function and activity level between patients with primary and revision anterior cruciate ligament reconstruction (ACLR) is to perform a matched-group analysis. The aim was to assess and compare knee function, knee-related quality of life and activity level between patients with revision ACLR and primary ACLR at a minimum of 5 years of follow-up. Methods: Patients aged ≤ 40 years old who underwent revision ACLR between 2010 and 2015 and a matched control group (primary ACLR) (1:1) with age ± 2 years, year of ACLR, sex, and pre-injury sport and Tegner Activity Scale (TAS) were retrospectively identified in our clinic database. The preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) and surgical data were extracted and analyzed. Patients were mailed KOOS and EQ-5D questionnaires at a minimum of 5-years after revision ACLR. Study-specific questions about knee function, limitation in sport, satisfaction, and activity level according to the TAS (all scales of 1–10, 10 best) were also asked by telephone. Results: Seventy-eight patients with a revision ACLR (mean age ± SD, 29.9 ± 6.0 years) matched with seventy-eight patients with a primary ACLR (30.2 ± 5.8 years) were included. The follow-up for the revision ACLR group was 7.0 ± 1.5 years and for the primary ACLR group 7.7 ± 1.6 years. The revision ACLR group reported poorer KOOS scores in all subscales (p < 0.05) except the Symptoms subscale, poorer EQ-5D VAS (mean 79.2 ± 20.1 vs 86.0 ± 20.1, p = 0.012), and less satisfaction with current knee function (median 7 (6–8) vs 8 (7–9), p < 0.001). Patients with revision ACLR also experienced greater limitation in sports (median 7 (4–8) vs 8 (6–9), p < 0.001). There were no significant differences in the EQ-5D (mean 0.86 ± 0.17 vs 0.89 ± 0.11, p = 0.427), activity level (median 2 (2–5) vs 4 (2–7), p = 0.229), or satisfaction with activity level (median 8 (5–9) vs 8 (6–10), p = 0.281) between the groups. Conclusions: At a minimum 5-year follow-up, the revision ACLR group reported poorer knee function and quality of life, less satisfaction with knee function and a greater limitation in sports but no differences in activity level and satisfaction with activity level compared with the primary ACLR group. [ABSTRACT FROM AUTHOR]

Background: Little is known about knee mechanics and muscle control after augmented ACL repair. Our aim was to compare knee biomechanics and leg muscle activity during walking between the legs of patients 2 years after InternalBraceTM-augmented anterior cruciate ligament repair (ACL-IB) and between patients after ACL-IB and ACL reconstruction (ACL-R), and controls. Methods: Twenty-nine ACL-IB, 27 sex- and age-matched ACL-R (hamstring tendon autograft) and 29 matched controls completed an instrumented gait analysis. Knee joint angles, moments, power, and leg muscle activity were compared between the involved and uninvolved leg in ACL-IB (paired t-tests), and between the involved legs in ACL patients and the non-dominant leg in controls (analysis of variance and posthoc Bonferroni tests) using statistical parametric mapping (SPM, P < 0.05). Means and 95% confidence intervals (CI) of differences in discrete parameters (DP; i.e., maximum/minimum) were calculated. Results: Significant differences were observed in ACL-IB only in minimum knee flexion angle (DP: 2.4°, CI [-4.4;-0.5]; involved > uninvolved) and maximum knee flexion moment during stance (-0.07Nm/kg, CI [-0.13;-0.00]; involved < uninvolved), and differences between ACL-IB and ACL-R only in maximum knee flexion during swing (DP: 3.6°, CI [0.5;7.0]; ACL-IB > ACL-R). Compared to controls, ACL-IB (SPM: 0–3%GC, P = 0.015; 98–100%, P = 0.016; DP: -6.3 mm, CI [-11.7;-0.8]) and ACL-R (DP: -6.0 mm, CI [-11.4;-0.2]) had lower (maximum) anterior tibia position around heel strike. ACL-R also had lower maximum knee extension moment (DP: -0.13Nm/kg, CI [-0.23;-0.02]) and internal knee rotation moment (SPM: 34–41%GC, P < 0.001; DP: -0.03Nm/kg, CI [-0.06;-0.00]) during stance, and greater maximum semitendinosus activity before heel strike (DP: 11.2%maximum voluntary contraction, CI [0.1;21.3]) than controls. Conclusion: Our results suggest comparable ambulatory knee function 2 years after ACL-IB and ACL-R, with ACL-IB showing only small differences between legs. However, the differences between both ACL groups and controls suggest that function in the involved leg is not fully recovered and that ACL tear is not only a mechanical disruption but also affects the sensorimotor integrity, which may not be restored after surgery. The trend toward fewer abnormalities in knee moments and semitendinosus muscle function during walking after ACL-IB warrants further investigation and may underscore the importance of preserving the hamstring muscles as ACL agonists. Level of evidence: Level III, case-control study. Trial registration: clinicaltrials.gov, NCT04429165 (12/06/2020). [ABSTRACT FROM AUTHOR]

Abstract Background Rates of return to physical activity after anterior cruciate ligament reconstruction surgery are sub-optimal. Optimising presurgical treatment may improve return rates. The purpose of this systematic review was to identify modifiable preoperative predictors for return to physical activity after anterior cruciate ligament reconstruction. Methods Seven electronic databases (CINAHL, MEDLINE and SPORTDiscus via EBSCOhost, AMED, PsycINFO and EMBASE via OVID and Web of Science) were searched from inception to 31 March 2023. The population of focus was adults aged 18–65 who had undergone primary anterior cruciate ligament reconstruction. Studies needed to identify at least one potential modifiable preoperative predictor variable and the relationship between the predictor(s) and return to physical activity. All time-points of assessment and study designs were included. Data extraction was completed by one reviewer and verified by a second reviewer. Two reviewers completed the risk of bias assessment using the Quality in Prognostic Studies tool and Grading of Recommendations Assessment, Development and Evaluation system. Results The search identified 2281 studies, eight met the inclusion criteria. Five studies scored ‘high’, and three studies scored ‘moderate’ risk-of-bias. All preoperative predictors were of very low-quality evidence. Five different outcome measures were used to assess return to physical activity including Tegner, Marx, Physical Activity Scale, return to play at the elite level and return to preinjury level (undefined). This was measured between 1- and 10-years post-surgery. Nine preoperative physical, six psychosocial and five demographic/clinical factors were assessed and four were found to be predictive. These included quadriceps strength, psychological profile, patient estimated ability to return and graft type (patella tendon, BPTB). Conclusion Very-low level evidence suggests that increasing quadriceps strength, managing patient expectations of their treatment outcomes, improving motivation to resume preinjury activity levels and considering the use of a BPTB graft will support return to physical activity after ACLR. Trial registration This study was prospectively registered in PROSPERO: CRD 42020222567.

Background: Different types of grafts can be used for anterior cruciate ligament reconstruction (ACLR). There is little published data regarding skeletally immature patients. The purpose of this systematic review was to assess the clinical outcomes and complications for different autograft types used in all-epiphyseal, transphyseal and partial epiphyseal/hybrid ACLR in skeletally immature children and adolescents. Methods: PubMed, Embase and Cochrane databases were systematically searched for literature regarding ACLR using hamstrings, quadriceps or bone-patellar-tendon-bone (BPTB) autografts in skeletally immature patients. Studies were included if they examined at least one of the following outcomes: graft failure, return to sport(s), growth disturbance, arthrofibrosis or patient reported outcomes and had a minimum follow-up of 1 year. Case reports, conference abstracts and studies examining allografts and extra-articular or over-the-top ACL reconstruction techniques were excluded. Graft failure rates were pooled for each graft type using the quality effects model of MetaXL. A qualitative synthesis of secondary outcomes was performed. Results: The database search identified 242 studies. In total 31 studies were included in this review, comprising of 1358 patients. Most patients (81%) were treated using hamstring autograft. The most common used surgical technique was transphyseal. The weighted, pooled failure rate for each graft type was 12% for hamstring tendon autografts, 8% for quadriceps tendon autografts and 6% for BPTB autografts. Confidence intervals were overlapping. The variability in time to graft failure was high. The qualitative analysis of the secondary outcomes showed similar results with good clinical outcomes and low complication rates across all graft types. Conclusions: Based on this review it is not possible to determine a superior graft type for ACLR in skeletally immature. Of the included studies, the most common graft type used was the hamstring tendon. Overall, graft failure rates are low, and most studies show good clinical outcomes with high return to sports rates. [ABSTRACT FROM AUTHOR]

Abstract Background 3D printing technology has become a research hotspot in the field of scientific research because of its personalized customization, maneuverability and the ability to achieve multiple material fabrications. The focus of this study is to use 3D printing technology to customize personalized poly L-lactic acid (PLLA) porous screws in orthopedic plants and to explore its effect on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction. Methods Preparation of PLLA porous screws with good orthogonal pore structure by 3D printer. The hydroxyapatite (HA) was adsorbed on porous screws by electrostatic layer-by-layer self-assembly (ELSA) technology, and PLLA-HA porous screws were prepared. The surface and spatial morphology of the modified screws were observed by scanning electron microscopy (SEM). The porosity of porous screw was measured by liquid displacement method. Thirty New Zealand male white rabbits were divided into two groups according to simple randomization. Autologous tendon was used for right ACL reconstruction, and porous screws were inserted into the femoral tunnel to fix the transplanted tendon. PLLA group was fixed with porous screws, PLLA-HA group was fixed with HA modified porous screws. At 6 weeks and 12 weeks after surgery, 5 animals in each group were sacrificed randomly for histological examination. The remaining 5 animals in each group underwent Micro-CT and biomechanical tests. Results The pores of PLLA porous screws prepared by 3D printer were uniformly distributed and connected with each other, which meet the experimental requirements. HA was evenly distributed in the porous screw by ELSA technique. Histology showed that compared with PLLA group, mature bone trabeculae were integrated with grafted tendons in PLLA-HA group. Micro-CT showed that the bone formation index of PLLA-HA group was better than that of PLLA group. The new bone was uniformly distributed in the bone tunnel along the screw channel. Biomechanical experiments showed that the failure load and stiffness of PLLA-HA group were significantly higher than those of PLLA group. Conclusions The 3D printed PLLA porous screw modified by HA can not only fix the grafted tendons, but also increase the inductivity of bone, promote bone growth in the bone tunnel and promote bone integration at the tendon-bone interface. The PLLA-HA porous screw is likely to be used in clinic in the future.

Abstract Background To investigate the clinical application of modified Crain classification in anterior cruciate ligament (ACL) reconstruction (ACLR) with remnant preservation. Methods The subjects were 70 patients with ACL injury who underwent ACLR from May 2016 to June 2018, and their general data were recorded. They were randomly divided into modified remnant-preserved ACLR group (group M, n = 35) and non remnant-preserved ACLR group (group N, n = 35). ACLR program with remnant preservation was designed based on modified Crain classification in group M, while ACL remnants were completely cleaned during ACLR in group N. Subsequently, the two groups were compared in terms of operation time, complications, as well as Lysholm score, international knee documentation committee (IKDC) score and positive rate of Lachman test of knee joint before operation and at 3, 6 and 12 months after operation. Results Both the groups showed good postoperative efficacy, and none had complications like limited knee extension or cyclops lesion. The comparison results found that group M (72.49 ± 7.64 min) required longer operation time than group N (66.06 ± 6.37 min) (P

Background: Rates of return to physical activity after anterior cruciate ligament reconstruction surgery are sub-optimal. Optimising presurgical treatment may improve return rates. The purpose of this systematic review was to identify modifiable preoperative predictors for return to physical activity after anterior cruciate ligament reconstruction. Methods: Seven electronic databases (CINAHL, MEDLINE and SPORTDiscus via EBSCOhost, AMED, PsycINFO and EMBASE via OVID and Web of Science) were searched from inception to 31 March 2023. The population of focus was adults aged 18–65 who had undergone primary anterior cruciate ligament reconstruction. Studies needed to identify at least one potential modifiable preoperative predictor variable and the relationship between the predictor(s) and return to physical activity. All time-points of assessment and study designs were included. Data extraction was completed by one reviewer and verified by a second reviewer. Two reviewers completed the risk of bias assessment using the Quality in Prognostic Studies tool and Grading of Recommendations Assessment, Development and Evaluation system. Results: The search identified 2281 studies, eight met the inclusion criteria. Five studies scored 'high', and three studies scored 'moderate' risk-of-bias. All preoperative predictors were of very low-quality evidence. Five different outcome measures were used to assess return to physical activity including Tegner, Marx, Physical Activity Scale, return to play at the elite level and return to preinjury level (undefined). This was measured between 1- and 10-years post-surgery. Nine preoperative physical, six psychosocial and five demographic/clinical factors were assessed and four were found to be predictive. These included quadriceps strength, psychological profile, patient estimated ability to return and graft type (patella tendon, BPTB). Conclusion: Very-low level evidence suggests that increasing quadriceps strength, managing patient expectations of their treatment outcomes, improving motivation to resume preinjury activity levels and considering the use of a BPTB graft will support return to physical activity after ACLR. Trial registration: This study was prospectively registered in PROSPERO: CRD 42020222567. [ABSTRACT FROM AUTHOR]

Abstract Background The number of studies with a large cohort of patients that primarily focus on patient-reported outcomes after ACL reconstruction in children and adolescents is limited. The purpose of the present study was to determine whether patient age affects the proportion of patients that achieve a patient-acceptable symptom state (PASS) on the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales one, two, five and 10 years after an ACL reconstruction. Methods The patient data in the present study were extracted from the Swedish National Knee Ligament Register (SNKLR). Patients aged between five and 35 years that underwent a primary ACL reconstruction between 1 January 2005 and 31 December 2017 and had completed the KOOS questionnaire at the one-, two-, five- or 10-year follow-up were included. A total of 2,848 patients met the inclusion criteria and were included in the study; 47 paediatric patients (females 5–13, males 5–15 years), 522 adolescents (females 14–19, males 16–19 years) and 2,279 young adults (females 20–35, males 20–35 years). The results from the KOOS were presented as the mean and 95% confidence interval (CI) for the mean. For comparisons between groups, the chi-square test was used for non-ordered categorical variables. For pairwise comparisons between groups, Fisher’s exact test (2-sided) was used for dichotomous variables. All the statistical analyses was set at 5%. Results Adolescents reported a significantly lower score than young adults on the KOOS4 at the two- (68.4 vs. 72.1; P

Abstract Background Despite anterior cruciate ligament (ACL) re-ruptures being common, research on patient experiences after knee trauma has primarily focused on the time after primary ACL reconstruction. Integrating qualitative research and patient experiences can facilitate researchers and clinicians in understanding the burden of an ACL re-rupture. The aim of the study was to explore the experiences of an ACL re-rupture journey in young active females aiming to return to knee-strenuous sports after primary ACL reconstruction. Method Fifteen young (19[range 16–23] years old) active females who suffered an ACL re-rupture were interviewed with semi-structured interviews. Qualitative content analysis using deductive approach based on Wiese-Bjornstal’s ‘integrated model of response to sport injury’ was used. Results The results are presented in two timelines 1) from first ACL injury to ACL re-rupture, and 2) from ACL re-rupture to present day, and further stratified according to the domains of the ‘integrated model of psychological response to injury’. Results in the first timeline are summarised into seven categories: Finding hope for the journey; Accepting my ACL injury; I succeeded; What matters now? Who am I?; Where will this end? What is going to happen? In the second timeline, eight categories were identified: Fighting spirit; A helping hand; Working hard; I am a new me; I am destroyed; Loneliness; Painful changes; and, I could have made it to the pro´s. Conclusion Young active females who suffered an ACL re-rupture did not express any positive experience following their first ACL injury, however, in contrast, expressed positive experiences and personal growth after going through the ACL re-rupture journey, characterized by a lot of struggling, and ultimately led to the experience of becoming a new, stronger person.

Abstract Background Osteopetrosis is an uncommon inherited disease marked with elevated bone density and frequent bone fractures owing to flawed osteoclast activity. Autosomal dominant osteopetrosis type 2 (ADO-2), a benign form of osteopetrosis, is also known as Albers-Schonberg disease. Case presentation We report the first successful anterior cruciate ligament (ACL) reconstruction surgery for ACL rupture treatment in a 30-year-old female with ADO-2, who carried a heterozygous missense mutation c.2227C > T (p.Arg743Trp) in exon 23 of the chloride channel 7 (CLCN7) gene. Histopathological analysis of the ruptured ACL sample revealed massive calcium salt deposition in the ligament tissue. A ligament advanced reinforcement system (LARS) artificial ligament was employed in her ACL reconstruction surgery. At her final 16 month’s follow-up, she reported no knee instability symptoms and other complications. The range of motion of the affected knee was good. The side-to-side difference in knee laxity, as evidenced by a KT-1000 arthrometer was 0.9 mm. The Lysholm score improved from 45 before operation to 83 after operation. The Tegner activity score improved from 1 before operation to 4 after operation. Conclusions Our findings further confirmed that the newly identified mutated locus (p.Arg743Trp) may lead to acid secretion disorders at different sites (including calcified ACL in our case). In terms of clinical treatment, ligament reconstruction surgery in patients with Albers-Schonberg disease presents a unique challenge to orthopedic surgeons and requires further preparation and time.

Background: 3D printing technology has become a research hotspot in the field of scientific research because of its personalized customization, maneuverability and the ability to achieve multiple material fabrications. The focus of this study is to use 3D printing technology to customize personalized poly L-lactic acid (PLLA) porous screws in orthopedic plants and to explore its effect on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction. Methods: Preparation of PLLA porous screws with good orthogonal pore structure by 3D printer. The hydroxyapatite (HA) was adsorbed on porous screws by electrostatic layer-by-layer self-assembly (ELSA) technology, and PLLA-HA porous screws were prepared. The surface and spatial morphology of the modified screws were observed by scanning electron microscopy (SEM). The porosity of porous screw was measured by liquid displacement method. Thirty New Zealand male white rabbits were divided into two groups according to simple randomization. Autologous tendon was used for right ACL reconstruction, and porous screws were inserted into the femoral tunnel to fix the transplanted tendon. PLLA group was fixed with porous screws, PLLA-HA group was fixed with HA modified porous screws. At 6 weeks and 12 weeks after surgery, 5 animals in each group were sacrificed randomly for histological examination. The remaining 5 animals in each group underwent Micro-CT and biomechanical tests. Results: The pores of PLLA porous screws prepared by 3D printer were uniformly distributed and connected with each other, which meet the experimental requirements. HA was evenly distributed in the porous screw by ELSA technique. Histology showed that compared with PLLA group, mature bone trabeculae were integrated with grafted tendons in PLLA-HA group. Micro-CT showed that the bone formation index of PLLA-HA group was better than that of PLLA group. The new bone was uniformly distributed in the bone tunnel along the screw channel. Biomechanical experiments showed that the failure load and stiffness of PLLA-HA group were significantly higher than those of PLLA group. Conclusions: The 3D printed PLLA porous screw modified by HA can not only fix the grafted tendons, but also increase the inductivity of bone, promote bone growth in the bone tunnel and promote bone integration at the tendon-bone interface. The PLLA-HA porous screw is likely to be used in clinic in the future. [ABSTRACT FROM AUTHOR]

Abstract Background Sports related injuries are the leading cause of Anterior Cruciate Ligament (ACL) tear in the Western world. Although professional and recreational sporting activities are increasing in Nepal, they are not as common and prevalent in comparison to western world. In contrast, Road Traffic Accident (RTA) is a very common cause of knee injuries in Nepal. Although there are some studies from Nepal mentioning Road Traffic Accidents (RTAs) as the most common cause of ACL injury, no specific studies have primarily investigated the epidemiological and demographic profile of ACL injured patients from this region. we aimed to understand the epidemiological and demographic profile of ACL injured patients and evaluate the mode of injury in a tertiary referral trauma center of Nepal. Methods This was a retrospective descriptive study of a hospital cohort conducted from February 2018 to January 2020. Electronic details were retrieved, telephone interviews conducted and data analysis was done using descriptive analysis on the patients from the fore mentioned dates to complete demographic and epidemiological information. Results A total of 237 patients were enrolled in this study. Among these, 120 patients (50.6%) fell into the age group of 15–30 years with a male to female ratio of 2.7:1. A RTA was the most common cause of ACL injury (38.8%), followed by sports-related injuries in 33.3% and falls in 16.5% of patients. The most common mode of RTA was a two-wheeler accident, and football was the most common sport causing ACL injuries. Sports injury was more common in patients below 30 years of age (OR = 3.5, 95% CI [2.2, 5.7]), whereas RTA was more common in patients above 30 years of age. Sports was the cause of ACL injury in 55.5% of students and RTAs was the commonest cause of ACL injury in office workers. Conclusion Overall males were more frequently injured than females. Road traffic accidents were the most common cause of ACL injury in our subset of patients. Two-wheeler riders were the most commonly injured patients. Sport was the commonest cause of ACL injury in patients below 30 years, and RTA was common in patients above 30 years of age. Sports were the commonest cause of ACL injury in students, while RTA was the most common cause in office workers.

Abstract Background The development of computer-assisted technologies to diagnose anterior cruciate ligament (ACL) injury by analyzing knee magnetic resonance images (MRI) would be beneficial, and convolutional neural network (CNN)-based deep learning approaches may offer a solution. This study aimed to evaluate the accuracy of a CNN system in diagnosing ACL ruptures by a single slice from a knee MRI and to compare the results with that of experienced human readers. Methods One hundred sagittal MR images from patients with and without ACL injuries, confirmed by arthroscopy, were cropped and used for the CNN training. The final decision by the CNN for intact or torn ACL was based on the probability of ACL tear on a single MRI slice. Twelve board-certified physicians reviewed the same images used by CNN. Results The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the CNN classification was 91.0%, 86.0%, 88.5%, 87.0%, and 91.0%, respectively. The overall values of the physicians’ readings were similar, but the specificity was lower than the CNN classification for some of the physicians, thus resulting in lower accuracy for the human readers. Conclusions The trained CNN automatically detected the ACL tears with acceptable accuracy comparable to that of human readers.

Abstract Purpose To determine the repair of LMPR lesions would improve the ACL graft maturation. Method A total of 49 patients underwent ACL reconstruction were included in this study. Patients were furtherly sub-grouped according to the status of LMPR: intact (17), repair (16) and resected (16). Assessments performed pre- and 2 years post-operatively included patients-reported scores and arthrometer side-to-side difference. Magnetic resonance imaging was used 2 years after the surgery to compare the lateral meniscal extrusion (LME), anterior tibial subluxation of the medial compartment (ATSMC), anterior tibial subluxation of the lateral compartment (ATSLC), the difference of ATSMC and ATSLC, and signal/noise quotient (SNQ) of ACL graft. Results In LMPR resected group, it showed greater post-operative ATSMC-ATSLC difference when compared with pre-operatively (P = 0.006) and with the other 2 groups (intact: P = 0.031; repair: P = 0.048). SNQ of ACL graft was higher in LMPR resected group than those in LMPR intact (P = 0.004) and repair group (P = 0.002). The LMPR repair group showed significant reduction in LME post-operatively (P = 0.001). Post-operative measures on ATSLC-ATSMC difference (β = 0.304, P = 0.049) and LME (β = 0.492, P = 0.003) showed significant association with graft SNQ. Conclusions Transtibial repair of LMPR concomitant with ACL reconstruction restored translational stability, reduced meniscus extrusion, making it beneficial for ACL graft maturation.

Abstract Background Measurement of the posterior tibial slope (PTS) angle has important applications in total knee replacement surgery, high tibial osteotomy, and anterior cruciate ligament reconstruction. This study aimed to determine the mean PTS of knee joints in healthy Chinese adults, and provide data to guide knee surgery in China. Methods A retrospective analysis of 1257 (n = 1233, 50.4% male) plain X-ray films of participants aged 25–59 years was performed. The picture archiving and communication system was used for PTS measurement. The PTS was defined as the angle between the vertical line of the tangent of the anterior tibial cortex of the proximal tibia, and the tangent line of the tibial cortex. Two imaging physicians conducted the PTS measurements independently, and both the inter- and intraclass correlation coefficients (ICCs) were calculated. Results The mean PTS value was 7.68 ± 3.84° (range: 0–21°). The left PTS was significantly smaller in males than in females (7.22 ± 3.89 vs 8.05 ± 3.60; P = 0.005). Additionally, the PTS in participants aged 25–29 years was significantly larger than that in the other age groups (Left side: 8.64 ± 3.73 vs 6.92 ± 3.42, 7.42 ± 3.75, 7.53 ± 3.98; P

Abstract Background Risk for non-contact anterior cruciate ligament (ACL) injury can be assessed based on drop vertical jump (DVJ). However, biomechanics of DVJ may differ with various sporting activities. The purpose of the present study was to clarify whether biomechanical features of DVJ are different among various sporting activities in female athletes. Methods A total of 42 female athletes, including 25 basketball, 8 soccer and 9 volleyball players, participated in the current investigation. DVJ was done for each female athlete using a three-dimensional motion analysis system which consisted of six cameras, two force plates and 46 retro-reflective markers. Kinematic and kinetic data were recorded for both limbs in each athlete. Simultaneously, frontal and sagittal plane views of the DVJ were recorded using two different high-resolution video cameras to evaluate Landing Error Scoring System (LESS) score. Three-dimensional biomechanical parameters at the knee joint and LESS were compared among three different sporting activities using ANOVA or Kruskal–Wallis test after confirming normality assumption. Thereafter post hoc Tukey or Steel–Dwass was utilized for multiple comparison. Results Soccer players had better LESS score, and peak knee flexion angle was significantly larger in soccer players compared to the other sports. In addition, knee abduction angle at initial contact (IC), peak knee abduction angle, knee internal rotation angle, and knee abduction moment within 40 ms from IC were significantly smaller in soccer players, compared to basketball players. In terms of volleyball players, knee abduction angle at IC and knee internal rotation angle at IC were significantly larger than soccer players, whereas no significant biomechanical differences were found between basketball and volleyball players. Conclusions From the present study, female basketball and volleyball players have worse LESS score, smaller peak knee flexion angle, greater knee abduction angle at IC and greater knee internal rotation angle at IC, compared to female soccer players. Thus, female basketball and volleyball players may have an increased risk of non-contact ACL injury during the jump-landing task, compared to soccer players. Biomechanics of DVJ depends on characteristics of the athlete's primary sport.

Abstract Background Studies have shown a significant association between the radiographically measured lateral femoral condyle ratio (LFCR) and anterior cruciate ligament (ACL) injury. However, it is unclear whether LFCR measured by magnetic resonance imaging (MRI) is associated with a higher risk of noncontact ACL injury. Objective To investigate the effect of LFCR on the risk of noncontact ACL injury by MRI. 2 to investigate the association of LFCR measured by MRI with multiple bone morphological risk factors and evaluate the most sensitive risk predictors of noncontact ACL injury. Methods A total of 116 patients, including 58 subjects with noncontact ACL injury and 58 age-matched and sex-matched controls with only meniscus injury, were included in this retrospective case-control study. LFCR, lateral tibial slope (LTS), lateral tibial height (LTH), medial tibial slope (MTS), and medial tibial depth (MTD) were measured on MRI. The differences in each index between the two groups were compared, and risk factors were screened by single-factor logistic regression analysis. Indicators with P values 2.35 mm), the diagnostic performance was improved. The AUC was 0.85 (95% CI, 0.78-0.92), the sensitivity was 0.83, and the specificity was 0.76. Conclusion This study shows that an increased LFCR is related to an increased risk of noncontact ACL injury as determined by MRI. LFCR and LTH are sensitive risk factors for noncontact ACL injury and may help clinicians identify individuals prone to ACL injury, allowing prevention and intervention measures to be applied.

Abstract Background The Norwegian Knee Ligament Register was founded in 2004 to provide representative and reliable data on cruciate ligament surgery. The aim of this study was to evaluate the validity of key variables in the Norwegian Knee Ligament Register to reveal and prevent systematic errors or incompleteness, which can lead to biased reports and study conclusions. Method We included a stratified cluster sample of 83 patients that had undergone both primary and revision anterior cruciate ligament surgery. A total of 166 medical records were reviewed and compared with their corresponding data in the database of the Norwegian Knee Ligament Register. We assessed the validity of a selection of key variables using medical records as a reference standard to compute the positive predictive values of the register data for the variables. Results The positive predictive values for the variables of primary and revision surgery ranged from 92 to 100% and from 39 to 100% with a mean positive predictive value of 99% and 88% respectively. Data on intraoperative findings and surgical details had high positive predictive values, ranging from 91 to 100% for both primary and revision surgery. The positive predictive value for the variable “date of injury” was 92% for primary surgeries but only 39% for revision surgeries. The positive predictive value for “activity at the time of injury” was 99% for primary surgeries and 52% for revisions. Conclusion Overall, the data quality of the key variables examined in the Norwegian Knee Ligament Register was high, making the register a valid source for research.

Abstract Background Meniscus root tear is an uncommon but detrimental injury of the knee. Hoop stress is lost during meniscus root tear, which can lead to excessive tibiofemoral contact pressure and early development of osteoarthritis. Posterolateral meniscus root tears (PLRT) are more commonly associated with anterior cruciate ligament (ACL) tears. As the lateral compartment is less congruent than the medial compartment, it is more susceptible to a shearing force, which is increased in the ACL-deficient knee. In accordance with the compressive axial load, the increase in the tibial slope would generate a greater shearing force. The additional lateral compartment mobility caused by ACL tear should be reduced after ACL reconstruction (ACLR). However, there is a lack of evidence to conclude that ACLR can sufficiently limit the effect of large tibial slope (LTS) on the healing after PLRT repair. This study aimed to evaluate whether a steep LTS would be a risk factor for poorer clinical outcomes after PLRT repair concomitant with ACLR. Methods In this retrospective study, a chart review was conducted to identify patients with concomitant unilateral primary ACLR and PLRT repair. Patients with a partial tear or healed tear were excluded. Postoperative MRI and clinical assessments were performed at a mean follow up of 35 months. MRI data was used to measure the LTS, medial tibial slope (MTS), coronal tibial slope (CTS), the lateral-to-medial slope difference (LTS-MTS) and meniscus healing and extrusion. Functional outcomes were evaluated by patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Tegner scores) and KT-1000 arthrometer assessment. Interobserver reproducibility was assessed by two reviewers. Results Twenty-five patients were identified for the analysis. Patients with larger LTS and larger LTS-MTS differences were shown to be correlated with poorer IKDC scores after surgery (R = -0.472, p = 0.017 and R = -0.429, p = 0.032, respectively). Herein, patients with LTS ≥ 6° or LTS-MTS ≥ 3° demonstrated poorer IKDC scores. Conclusion A large LTS (≥ 6°) and a large difference of LTS-MTS (≥ 3°) were shown to be risk factors for poorer functional and radiological outcomes for PLRT repair in patients after ACLR. Clinically, closer monitoring and a more stringent rehabilitation plan for patients with LTS ≥ 6° or LTS-MTS ≥ 3° would be recommended.