Young, active individuals who undergo anterior cruciate ligament (ACL) reconstruction (ACLR) after an ACL injury often experience suboptimal outcomes, including high risk of second ACL injury. Coupling angle variability has been used previously to investigate the interactions between joints and their relative coordination, but it has not yet been used to investigate future risk of subsequent ACL injury during dynamic tasks post-ACLR. As such, the purpose of this work was to examine the relationship between coordination variability and second ACL injury outcomes in young athletes after primary ACLR along with uninjured controls. This work represents a secondary analysis from a larger parent study that included motion capture data at the time of return to sport (RTS) and second ACL injury incidences over a two-year period after RTS in young athletes post-ACLR. We utilized kinematic data during landing to calculate coordination variability with a modified vector coding technique. For this analysis, coordination variability during the landing phase of a single leg landing task was compared among three groups: uninjured control participants (CTRL), participants with ACLR that did not sustain a subsequent second ACL injury (ACL1), and participants with ACLR that sustained a second ACL injury (ACL2). On the uninvolved limb, CTRL demonstrated lower coordination variability compared to ACL1 and ACL2. On the involved limb, CTRL demonstrated the lowest coordination variability and ACL2 demonstrated the highest coordination variability of the three groups. The higher coordination variability seen in the ACLR groups suggests lower consistency of movement strategies. Additional research is needed to further investigate how coordination variability may impact subsequent injury risk after primary ACLR.

This systematic review aimed to comprehensively assess the epidemiological profile of anterior cruciate ligament (ACL) injuries among volleyball athletes, focusing on incidence, prevalence, injury mechanisms, and athlete characteristics such as sex, age, and court position. Following PRISMA-S guidelines, a thorough search was performed in PubMed, Web of Science, and SCOPUS, covering publications until December 26, 2024. Eligible studies included peer-reviewed cohort research reporting the incidence or prevalence of ACL injuries specifically in volleyball players. The methodological quality of these studies was critically evaluated using the adapted STROBE checklist. From an initial pool of 1,491 titles, 15 studies met the inclusion criteria, encompassing data from 3,313,248 athletes aged 10–70 years. The analysis revealed a substantial variation in ACL injury rates, largely influenced by factors such as exposure time, competition level, and injury mechanism. Notably, non-contact mechanisms were the most frequent cause of ACL injuries, predominantly occurring during spike landings in competitive settings. Female athletes, particularly high school players and those in the outside hitter position, exhibited the highest incidence of ACL injuries. These findings underscore the significant impact of athlete sex, playing level, and positional role on ACL injury risk in volleyball. The predominance of non-contact injuries highlights a critical need for sport-specific, targeted prevention strategies, especially among high-risk groups, such as adolescent female athletes and outside hitters. By identifying these key risk factors, this review provides a foundational understanding to inform tailored interventions, ultimately enhancing athlete safety and performance.

Return to performance (RTPerf) after anterior cruciate ligament (ACL) surgery remains difficult to predict in elite alpine skiers, as general criteria may not fully apply. This study aimed to identify determinants and the time needed to achieve RTPerf at the same competitive level. A prospective cohort of 71 elite alpine skiers (mean age: 23.6 ± 5.2 years; height: 173.0 ± 7.8 cm; weight: 72.0 ± 12.1 kg) who underwent ACL surgery was analysed. Demographic and contextual variables, including sex, age, world ranking and type of injury, were collected. Isokinetic knee muscle strength was assessed six months postsurgery. RTPerf (YES/NO) and time to return were evaluated 2 years postoperatively using the International Ski and Snowboard Federation points system. Associations with categorical and quantitative variables were assessed using χ2 and t- or Mann-Whitney U tests. Variables with p < 0.2 were included in multivariable logistic regression. Predictors of return time were analysed using Cox regression and receiving operating characteristic (ROC) curves. Statistical significance was set at p < 0.05. Seventy-nine percent of skiers returned to preinjury performance within 2 years. Primary ACL injury (vs. revision) (odds ratio [OR]: 6.6; 95% confidence interval [CI]: 1.85-23.6; p = 0.004) and isolated injury (vs. complex) (OR: 5.35; 95% CI: 1.39-20.48; p = 0.014) were significant predictors. Average return time was 348 ± 51.6 days. Greater relative knee extensor strength was associated with earlier return. Limb symmetry in knee extension at 60°/s predicted return within 1 year, while the hamstring-to-quadriceps functional ratio at 90°/s predicted later return (area under the curve [AUC]: 0.78; p < 0.01). Primary and isolated ACL injuries were linked to higher RTPerf rates, while greater knee extensor isokinetic strength was associated with shorter time to RTPerf in elite alpine skiers. Level II.

To investigate whether the treatment method of a concomitant lateral meniscus (LM) injury during primary anterior cruciate ligament (ACL) reconstruction (ACLR) affects ACL revision rates in football (soccer) players, nonfootball pivoting athletes and nonpivoting patients differentially, when compared to controls. Data from the Swedish Knee Ligament Registry (SKLR) from 2005 to 2022 were used in univariate and multivariate logistic regression. The study compared two groups: patients with isolated ACLR and patients with ACLR and concomitant LM injury. These groups were further divided into activity type during injury (football, nonfootball pivoting and nonpivoting), as well as meniscal treatment type (repair, resection and left in situ). The outcome of interest was the ipsilateral ACL revision rate at 5 and 10 years after primary ACLR, when comparing the LM treatments among different activities at the time of injury. Five-year data were available for 21,848 patients, and 10-year data were available for 10,827 patients. Football players had higher odds of revision ACLR at 5 (odds ratio [OR]: 1.51 [1.34-1.72]; p < 0.0001) and 10 years (OR: 1.51 [1.27-1.79]; p < 0.0001). When compared to isolated ACLR in nonfootball pivoting athletes, nonfootball pivoting athletes with concomitant LM injury left in situ had higher odds of revision ACLR at 5 years (OR: 1.87 [1.07-3.30]; p = 0.0029) and 10 years (OR: 2.50 [1.18-5.29]; p = 0.017). Additionally, nonpivoting patients with concomitant LM injury left in situ had higher odds of revision ACLR at 10 years (OR: 2.34 [1.03-5.34]; p = 0.043) compared to nonpivoting patients undergoing isolated ACLR. Repair or resection of LM injuries were not associated with increased rates of revision ACLR in any of the study groups (p > 0.05). LM tears left untreated increased the odds of revision ACLR in nonfootball playing patients in the current study. However, in football players, who were observed to have increased odds of failure, there were no significant associations between LM management and revision ACLR. Level III.

The posterior tibial slope (PTS) is the inclination of the tibial plateau in the sagittal plane and is an important factor for knee joint biomechanics. Anormal PTS lies between 6 and 12°. Deviations, such as asteeper slope (> 12°) or aflatter slope (< 5°), are associated with characteristic biomechanical changes. This paper addresses the clinical significance of sagittal alignment and its effects on the risk of injury to cruciate ligaments, menisci, and cartilage. Furthermore, common radiological measurement methods and surgical corrections for pathological PTS values are investigated. The work summarizes findings from numerous biomechanical and clinical studies. The radiological determination of the PTS, as well as the surgical correction options, are presented in detail. An increased PTS is asignificant risk factor for ACL (anterior cruciate ligament) ruptures and graft failure after reconstruction. Avalue of > 12° has emerged as astatistical threshold in many studies, above which the risk increases significantly. Increased slope values are also associated with an elevated risk of meniscal root and ramp lesions. The evidence for an association with cartilage damage is still low. Conversely, aflatter slope (< 5°) increases the risk for PCL (posterior cruciate ligament) ruptures and re-ruptures. The correction of the PTS through aclosed-wedge osteotomy is frequently discussed in the literature for values > 12° and appears to reduce the risk of arenewed ACL rupture. The strong correlation between sagittal alignment and ligament instability underscores the central importance of the PTS in knee joint biomechanics. Consequently, PTS must be systematically included in the diagnostic workup as aprimary risk factor. In cases of ACL or PCL graft failure combined with apathological slope, operative correction should be discussed as acausal therapeutic option to minimize graft strain. However, high-quality prospective studies are necessary to conclusively prove the long-term superiority of this combined approach.

ObjectiveArtificial intelligence offers opportunities for timesaving assessments of multiple pathologies in large magnetic resonance imaging (MRI) data sets in knee osteoarthritis (KOA). This study evaluated their prevalence within pre-defined clinical phenotypes and their predictive value for knee replacement (KR).DesignBaseline MRIs (n = 8,667) from the Osteoarthritis Initiative were analyzed using a machine-learning (ML) algorithm. The presence of pathologies (menisci, anterior cruciate, medial collateral ligaments, cartilage, etc.) was assessed in previously identified phenotypic clusters (a post-traumatic, metabolic, and age-defined phenotype). The value of both, cluster allocation and joint pathology for KR prediction was evaluated using supervised ML models and time-dependent receiver operating characteristic curves.ResultsCompared to the population average, the metabolic cluster had a higher prevalence of cartilage lesions, while the post-traumatic one had more medial meniscal damage. Random forest models showed the best prediction (area under the curve 0.837, test set at 2 years). The top predictors for KR were meniscal position (relative to the border of the tibial plateau), severe joint effusion, medial femorotibial cartilage lesions, and metabolic phenotype. These features defined patients at high risk of KR with an estimated KR rate at 5 years of 10% vs 3% in the high- and low-risk groups based on a predictive risk score including all analyzed structures.ConclusionsThis ML-enabled assessment of multiple MRI pathologies in a large KOA data set highlights the importance of meniscal pathologies and markers of inflammation, in addition to cartilage assessments and clinical information for patient stratification and improved prediction of KOA progression to KR.

Background Anterior cruciate ligament (ACL) injuries in paraplegic patients are rare and pose unique challenges in treatment planning. Functional knee stability is critical for rehabilitation, especially in those regaining partial mobility. Case presentation A 26-year-old female with flaccid paraplegia following polytrauma developed symptomatic right knee instability. MRI (1.5 T) confirmed a complete ACL rupture. She underwent ACL reconstruction using an 8.5 mm graft combining ipsilateral hamstring and contralateral semitendinosus tendons. Arthroscopic reconstruction was performed via an anteromedial portal, with femoral suspensory fixation and tibial bioabsorbable screw. A tailored rehabilitation program incorporating neuromuscular stimulation led to progressive improvement in quadriceps strength (MRC Grade 2–4) and gait function. Conclusion ACL reconstruction can be a viable option in selected paraplegic patients with partial mobility recovery when mechanical instability impedes functional progress. This case underscores the importance of individualized surgical and rehabilitation strategies in this complex population.

Combine anterior cruciate ligament reconstruction and unicompartmental knee arthroplasty with image-based robotic surgery: a current surgical technique.

As female participation in sports, traditionally dominated by males continues to grow, a notable trend has emerged: female athletes are disproportionately affected by soft tissue injuries, with anterior cruciate ligament (ACL) injury having an incidence rate up to 9 times more frequently than in their male counterparts. The burden of soft tissue injuries in female athletes such as hamstring injury, ankle sprain, and ACL injury is exacerbated by the underrepresentation of elite female athletes in sports medicine, and therefore suboptimal prevention and rehabilitative methods. This manuscript delves into the anatomical, hormonal, and training-related factors that contribute to this disparity. It examines common injury patterns including knee, ankle, and hamstring injuries, elucidating the pathophysiological mechanisms involved. The severe impact of these injuries can jeopardise the careers of elite sportswomen and prompt the need for a paradigm shift in sports medicine. This paper provides a current overview of injury management and discusses essential changes in prevention and rehabilitation strategies to improve outcomes for female athletes. By examining the existing body of knowledge, this review focuses on proposing future interventions and prevention strategies that are tailored to the unique needs of female athletes.

Anterior cruciate ligament (ACL) injuries are common among physically active individuals, yet regional data from the Middle East remain limited. This study aimed to evaluate the clinical characteristics, surgical management, and early outcomes of ACL reconstruction in Jordan. We conducted a cross-sectional study of 350 patients who underwent ACL reconstruction at multiple tertiary centers in Jordan. Data on demographics, injury mechanisms, clinical findings, surgical techniques, and postoperative outcomes were collected and analyzed using descriptive statistics. Among 350 patients (median age 25; 91.4% male), injuries were due to sports (53.7%) or twisting (46.3%). Instability (87.4%), pain (83.4%), and effusion (76.5%) were common. Medial meniscus injuries occurred in 50.6%, lateral meniscus in 27.4%, and MCL in 8.9%. Hamstring grafts were used in 84.0% of cases. Return to sport was achieved in 82.6%. Complications included infection (1.7%), persistent pain (6.2%), instability (6.0%), and revision (0.6%). Most patients regained full extension and flexion (median 130°), with low follow-up pain and disability scores. This study highlights the clinical patterns and favorable outcomes of ACL reconstruction in a Jordanian population. The findings align with global benchmarks and emphasize the need for broader regional data to inform best practices in the Middle East.

Functional Outcomes Following Arthroscopic Anterior Cruciate Ligament Reconstruction (ACLR) With and Without Internal Bracing: A Prospective Study

Introduction Quadriceps lag, an inability to fully extend the knee actively, is a common issue following anterior cruciate ligament reconstruction (ACLR) surgery, often leading to prolonged rehabilitation and suboptimal recovery. This pilot study aimed to assess the effectiveness of incorporating a real-time visual biofeedback device into rehabilitation programs to improve quadriceps lag in ACLR patients. Subjects and Methods In this non-randomised, controlled pilot trial, twelve participants (mean age = 31.3 ± 6.4 years; 7 males, 5 females) with quadriceps lag post-ACLR were assigned to an experimental group (&lt;i&gt;n&lt;/i&gt; = 6) receiving biofeedback, and a control group (&lt;i&gt;n&lt;/i&gt; = 6) undergoing standard rehabilitation. The experimental group performed 10 repetitions per set, 3 sets per session, daily for 2 weeks. The control group received range of motion and strengthening exercises. Quadriceps lag was assessed using a real-time biofeedback device on days 1 and 10. Statistical analysis included the Shapiro–Wilk test for normality, Levene’s test for homoscedasticity, Wilcoxon Signed-Ranks for within-group comparisons, and Mann–Whitney U for between-group comparisons (&lt;i&gt;p&lt;/i&gt; &lt; 0.05). Results The biofeedback group’s quadriceps lag decreased from 15.5° (&lt;i&gt;SD&lt;/i&gt; = 2.8) to 1.83° (&lt;i&gt;SD&lt;/i&gt; = 1.3); the control group decreased from 14.5° (&lt;i&gt;SD&lt;/i&gt; = 1.3) to 6.0° (&lt;i&gt;SD&lt;/i&gt; = 1.8). The improvement in the biofeedback group was significantly larger (&lt;i&gt;p&lt;/i&gt; = 0.043), with large effect sizes (3.67 experimental, 3.19 control). Conclusions Real-time biofeedback significantly reduces quadriceps lag in ACLR patients. Further research with larger samples is needed. Integrating biofeedback into ACLR protocols could aid clinicians in monitoring and reducing quadriceps lag.

Lateral extra-articular tenodesis protects high-risk patients from the risk of re-rupture and improves patient-reported outcomes after primary anterior cruciate ligament repair: A retrospective cohort study with ≥2-year follow up.

Abstract Background:&amp;#xD;Conventional anterior cruciate ligament reconstruction (ACLR) offers a limited visual field, often causing inaccurate bone tunnel positioning and affecting surgical outcomes. To improve the accuracy of bone tunnel positioning, a Mixed Reality Navigation System for ACLR (MRNS-ACLR) is proposed.&amp;#xD;Method:&amp;#xD;An Electrode Marker Detection Network (EMDNet) is first proposed to achieve sub-pixel automatic marker localization in medical images, effectively reducing errors caused by manual selection in traditional methods. Building upon this, Adaptive Rigid Body Clustering via Encoding (ARBC-E) is developed to perform real-time classification and ordering of detected markers, laying a foundation for subsequent registration. To address intraoperative leg pose variations, the Dynamic Dual-Bone Registration Framework (DDRF) enables automatic alignment of virtual anatomical structures with the patient by dynamically registering the femur and tibia separately. Finally, a series of experiments validate the system’s registration accuracy and navigation stability.&amp;#xD;Results:&amp;#xD;Experimental results indicate that the EMDNet achieves a recall rate of 100%, a precision of 97.56%, and root mean square error (RMSE) of 0.42 mm. Phantom studies report an average target registration error (TRE) of 0.54 mm. Non-interventional human experiments yield an average TRE of 0.82 mm and registration time of 1.58 minutes, meeting the clinical standards.&amp;#xD;Conclusion:&amp;#xD;By utilizing high-precision automated alignment and real-time stereoscopic guidance, the proposed MRNS-ACLR helps physicians perform precise execution of bone tunnels with reduced intraoperative errors. Experimental results confirm the high accuracy and strong potential of this system for clinical applications.&amp;#xD;

Background:While the rate of anterior cruciate ligament (ACL) injuries and reconstruction procedures in children and adolescents is increasing, evidence of long-term outcomes after ACL reconstruction in skeletally immature patients is still lacking.Purpose:To assess the long-term survivorship from revision and reoperations and to analyze the functional results and patient-reported outcomes (PROs) in skeletally immature patients (with an open physis present at magnetic resonance imaging evaluation) who underwent ACL reconstruction with hamstrings tendon with an over-the-top (OTT) technique and a lateral extra-articular tenodesis (LET).Study Design:Case series; Level of evidence, 4.Methods:The database of a single institution was retrospectively searched for skeletally immature patients who underwent ACL reconstruction. Ipsilateral and/or contralateral reoperations were recorded. Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm, and Tegner Activity Level scores were collected at final follow-up. Survivorship was inspected through Kaplan-Maier method with ipsilateral ACL revision as endpoint. Differences in demographics and PROs were assessed through Student t test.Results:A total of 43 patients (mean age at surgery, 13.3 ± 1.6 years), all of whom underwent an OTT technique associated with a LET, at mean follow-up of 11.0 ± 2.7 years were included. Four patients (9%) underwent revision ACL in the ipsilateral knee at a mean of 5.3 ± 2.4 years after surgery, with a revision rate of 5% at 5-year and 10% at 10- and 15-year follow-ups. Four patients (9%) underwent arthroscopy for a new meniscal tear, and a further 5 patients (12%) underwent staple removal because of local discomfort. A total of 11 patients (26%) underwent ≥1 reoperation in the ipsilateral knee after a mean of 3.0 ± 2.1 years; and 8 patients (19%) underwent contralateral ACL reconstruction after a mean of 3.7 ± 3.0 years after surgery. Mean KOOS subscales were all above the Patient Acceptable Symptom State. Patients <13 years old at surgery showed worse Lysholm (82.0 vs 94.6; P = .025) and KOOS–Activities of Daily Living (96.7 vs 99.9; P = .025) compared with those ≥13 years.Conclusion:Patients showed high survivorship (90% of cases) from ACL revision at long-term follow-up. Still, more than one-quarter (26%) of skeletally immature patients who underwent physeal-sparing OTT plus LET technique needed a further operation in the ipsilateral knee. Higher rate of hardware removal procedures and lower functional reported outcomes were detected in patients aged <13.

Anterior cruciate ligament (ACL) injuries are common in sports and significantly affect athletes' health and performance. Integrating knee adduction moment (KAM) biofeedback into ACL injury prevention training has been shown to effectively reduce injury risk and enable athletes to safely engage in high-risk activities. However, current motion capture-based monitoring methods are impractical for on-field use due to their bulky setups and limited coverage. While Inertial Motion Unit (IMU)-based methods address some of these issues, their poor performance during high-risk tasks limits their applicability in real-world scenarios. This paper presents ACLGuard, a novel physics-aware KAM monitoring system designed for out-of-lab ACL injury prevention training. ACLGuard utilizes a combination of continuous monitoring with a set of IMUs and a one-time body capture with RGB-D camera. We identify key limitations in existing approaches, including insufficient body information and inadequate encoding of biomechanical principles. To overcome these challenges, we introduce a one-time RGB-D registration scheme to capture comprehensive body information and develop an inverse dynamics (ID)-guided modeling algorithm to incorporate biomechanical principles into the system. However, extracting kinematic features under high-risk conditions and obtaining representative body features with respect to ID principle are challenging. Even worse, these extracted imperfect features increase the ID-guided modeling difficulty for KAM estimation. To derive meaningful physical features, we propose a hybrid deep learning model referring to motion patterns and physical priors. For ID-guided modeling, we introduce an attention-enhanced multi-task learning framework to establish hidden physical mappings from imperfect features to KAM. We collect a dataset from 10 athletes and 9 non-athlete subjects, containing four main high-risk tasks in real-world ACL injury prevention. Evaluations show that ACLGuard achieves an average root mean square error of 0.176 Nm/kg and a normalized root mean square error of 11.5% in KAM estimation, comparable to existing markerless motion capture solutions but offers an on-field monitoring potential with a significantly simpler setup.

Are joint line convergence angle and tibial slope related to bucket handle medial meniscal tear in chronic anterior cruciate ligament insufficiency?

Anterior cruciate ligament injury is rarely the last dance for professional basketball players: High return to play with longer recovery times. A systematic review and meta-analysis.

Anterior cruciate ligament (ACL) injury among professional footballers represents a career-threatening injury with a high burden for athletes and teams. Debated issues in professional footballers after ACL reconstruction (ACLR) include time to return to play (RTP), level of play after surgery, and incidence and timing of sustaining a second ACL injury. To analyze RTP and performance 2 seasons after surgery of professional footballers who underwent ACLR, to evaluate factors influencing the timing of RTP and second injury risk, and to assess the level of RTP and performance after surgery. Case series; Level of evidence, 4. All professional male footballers who underwent ACLR using a hamstrings graft with or without a lateral extra-articular procedure at a single institution between 2002 and 2013 were retrospectively included. Demographic and intraoperative findings were extracted from the medical records. Data regarding the number of matches played in 5 seasons (injury season, the 2 seasons before, and the 2 seasons after the injury), the level of play in those 5 seasons, the time to return to the first official match, and reinjuries were extracted from publicly available databases, and patients were contacted to confirm. Univariate and multivariate analyses were conducted to identify factors influencing RTP and risk factors for second ACL injury. A total of 58 primary ACLRs were included; 20 (34.5%) participated in the first division (Serie A). RTP was 96.6% (56/58) after a mean of 6.4 ± 2.3 months, and return to match occurred after a mean of 7.5 ± 3.3 months. Patients without meniscal injury had a faster RTP (5.6 ± 1.6 months; P = .0016), while athletes with cartilage injury showed a longer time to RTP (10.2 ± 3.7 months; P = .0001) and resulted as a predictor for longer RTP (+4.4 months; P = .0047).In the second season after an ACL injury, 23% of footballers participated in a lower division with respect to the injury season, playing a mean of 20 ± 11 matches, with 65% of them participating in >20 games. The second injury rate was 15.8% (9 patients). The ipsilateral reoperation rate, including ACL revisions, was 28.1%. Additionally, returning to competitive play within 5 months of surgery was a significant predictor of a second ACL injury. Almost all patients returned to play after ACLR using hamstrings graft with over-the-top techniques, typically regaining preinjury performance by the second season after the injury. RTP time was shorter for isolated ACL injuries and longer when associated with meniscal or cartilage injury. Given the high risk of a second ACL injury on either knee and the high reoperation rate, RTP before 5 months should be discouraged, particularly in athletes <21 years.

Inadequate long-term outcomes are common following both surgical and non-surgical management of anterior cruciate ligament (ACL) rupture. Emerging evidence suggests that a bracing protocol may facilitate ligamentous healing; however, a period of immobilisation can induce muscle atrophy. This study aims to investigate the potential benefits of adding blood flow restriction (BFR) training to the conservative treatment of ACL rehabilitation. This is a double-blinded, two-arm randomised clinical trial. Participants in the intervention group will follow an exercise protocol using BFR training, while participants in the control group will follow the same protocol with sham-BFR. Both groups will follow the same bracing protocol. Individuals aged between 18 and 40years with an acute or subacute complete ACL tear confirmed by imaging will be eligible to participate. Emerging evidence suggests that a conservative period of joint immobilisation, in which positioning the knee reduces the distance between the two torn ligament ends, may promote ACL healing after a complete rupture. However, the use of a brace can result in muscle atrophy. BFR exercises may play an important role during this period of immobilisation and restricted movement. Positive results of exercise under BFR, in combination with a brace, could serve as an alternative treatment for participants with acute or subacute complete ACL tears, potentially reducing recovery time or even avoiding surgery. Trial registration This protocol was approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2024/70) and registered on ClinicalTrials.gov (Registration number: NCT06727344).