Difference of Knee Strength Recovery Between Revision and Primary ACL Reconstruction.

Different grafting procedures are available to restore knee stability after revision anterior cruciate ligament (ACL) reconstruction. We compared knee strength recovery between ACL revision surgery and primary reconstruction. One hundred and ten patients with ACL revision surgery were matched with 110 patients with primary reconstruction based on the graft procedure. The isokinetic knee strength had been assessed for the first 9 months post-surgery. Knee laxity, function, and activity score were also evaluated. Limb symmetry index for knee extensor and flexor strength was not different at 4-, 6- and 9-months post-surgery between revision surgery and primary reconstruction. These results depended on ipsilateral or contralateral graft choice. Ipsilateral hamstring tendon (HT) and contralateral bone-patellar-tendon-bone (BPTB) graft procedures were similar for a revision of a BPTB graft failure. Contralateral HT procedure was better than ipsilateral BPTB procedure for a revision of a HT graft failure. The early recovery of isokinetic knee strength after ACL revision surgery regardless of the HT or BPTB procedures, was similar to the recovery after primary ACL reconstruction with the same graft technique. These results apparently depended on a temporary quadriceps arthrogenic muscle inhibition and on a persistent donor site morbidity, concerning the new and the previous grafts, respectively.

Enlightenment on Knee Flexors Strength Loss in Cases of Posterior Knee Pain After Anterior Cruciate Ligament Reconstruction.

CONTEXT: The persistence and the recurrence of posterior medial knee pain (PKP) after anterior cruciate ligament reconstruction (ACLR) using hamstring tendon graft are often overlooked during rehabilitation. DESIGN: Cross-sectional observational study. METHODS: The study aimed (1) to evaluate the prevalence of these types of PKP before 4 months post-ACLR, (2) to measure their consequences on the knee flexors strength, and (3) to evaluate the role of the type of ACLR. From a cohort of patients operated on with hamstring tendon procedures, the persistent and the recurrent PKP were sought at 4 months post-ACLR. The evolution of isokinetic muscle strength recovery in PKP subjects was compared with those of nonpainful subjects. The functional deficit was measured at 6/7 months post-ACLR by a hop test. RESULTS: Three hundred seventeen subjects (25.8 [6.0] y) were included. At 4 months post-ACLR, 2 populations were identified based on the recurrent onset of PKP (PKP+, n = 40) or the absence of knee pain (PKP-, n = 277). The prevalence of PKP was 8.3%. At the fourth month post-ACLR, the PKP+ group had a higher flexor strength deficit compared with the PKP- group (limb symmetry index at 60°/s: 67.2% [12.4%] vs 84.3% [12.6%]; P < .05). At 6/7 months, the loss of strength persisted (limb symmetry index at 60°/s: 82.3% [13.4%] vs 87.7% [12.8%]; P < .05). The hop test deficit was comparable, and no difference was shown according to the type of graft. CONCLUSIONS: Persistent and recurrent PKP during the rehabilitation period were not uncommon and were associated with a worsening of flexors strength loss on the ACLR side.

Artistic Swimming Injuries in Young Elite Athletes: An 11-year Follow-Up.

OBJECTIVE: Artistic swimming is a highly challenging discipline, requiring physical skills and creativity. There are almost no published data on trauma. We aimed to assess the incidence and the nature of injuries in artistic swimmers. DESIGN: An 11-year retrospective single-center cohort study. SETTING: Department of Sport Medicine of a University Hospital. PATIENTS: One hundred and twenty-four elite female artistic swimmers aged 12.9 ± 1.6 years. INTERVENTIONS: The cohort was divided into 3 groups according to the competition categories (from 9 to 12 years old called "future", 12-15 years old called "youth", 15-19 years old called "junior"). MAIN OUTCOME MEASURES: Injury rate per season and per athlete was assessed. RESULTS: The injury rate was 0.95 injuries/season/athlete and 1.05 injuries/1000 hours of practice. The most frequent injuries were rotator cuff tendinopathy (13.6%), acute low back pain (13.6%), and patellofemoral syndrome (11.9%). Swimmers in the youth and junior categories had significantly more injuries than those in the future category (P = 0.009), possibly because of more training hours (P < 0.001). Twelve major injuries occurred, all in the same group of youth swimmers. CONCLUSION: This is the first study investigating trauma during artistic swimming practice. A better knowledge of the main injuries is necessary for the physician to provide optimal care for athletes and to develop prevention. Attention should be particularly paid to the swimmers' shoulders and knees.

Consequences of Patellar Tendinopathy on Isokinetic Knee Strength and Jumps in Professional Volleyball Players.

Patellar tendinopathy (PT) in professional volleyball players can have an impact on their careers. We evaluated the impact of this pathology in this specific population in terms of isokinetic strength and jumping performances. Thirty-six professional male volleyball players (mean age: 24.8 ± 5.2) performed isokinetic knee assessments, single-leg countermovement jumps and one leg hop test. They filled out the Victorian Institute of Sport Assessment-Patella (VISA-P) score. Two groups were assessed: "PT group" (n = 15) and "control group" (n = 21). The VISA-P score was lower in the PT group (p < 0.0001). No difference was found between the isokinetic strength limb symmetry index and the jump performance limb symmetry index. The healthy legs of the control group were compared with the affected (PT+) and the unaffected legs (PT−) of the PT group. Compared with the healthy legs, both PT+ and PT− legs showed decreased values of quadriceps and hamstring strengths. Only PT+ legs scored lower than healthy legs in countermovement jumps and hop tests. No differences were found between PT+ and PT− legs for muscle strengths and jumps. A low correlation existed between quadriceps strength and jumping performances (r > 0.3; p < 0.001). Volleyball players with PT showed a decrease in the isokinetic knee strength. This strength deficit was found both on the symptomatic legs and the asymptomatic ones. Jumps were only significantly altered on the pathological legs. Highlighting that the unaffected limbs were also impaired in addition to the affected limbs may help provide a better adaptation of the rehabilitation management.

Isokinetic knee strength deficit in patients with moderate haemophilia.

INTRODUCTION: Knee joint bleedings are responsible for quadriceps atrophy and strength deficit in patients with severe haemophilia. Little is known about patients with moderate haemophilia (PWMH). AIM: To evaluate isokinetic quadriceps and hamstrings strength in PWMH and to assess correlation with radiological and clinical parameter. METHODS: 18 PWMH aged 37.1 ± 11.4 and 18 healthy age-, weight- and height-matched controls performed a knee isokinetic test at 180°/s to assess quadriceps and hamstrings strength. In the PWMH group, knee Pettersson's score was pursued and Haemophilia Joint Health Score 2.1 (HJHS) was performed to determine unaffected knees (knee HJHS = 0) and affected ones (knee HJHS >0). RESULTS: Affected knees had a decrease of quadriceps strength compared to controls, 1.26 ± 0.47 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.60 ± 0.29 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). Unaffected knees also had a decrease of quadriceps strength compared to controls, 1.36 ± 0.31 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.69 ± 0.18 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). The conventional hamstring-to-quadriceps ratio was significantly decreased in affected knees compared to controls, 0.46 ± 0.15 vs 0.64 ± 0.13 (P < 0.001) but also in unaffected knees, 0.53 ± 0.16 vs 0.64 ± 0.13 (P = 0.02).No correlation was found between strength and HJHS or Pettersson's score. CONCLUSION: PWMH have a significant knee strength deficit, both on the quadriceps and the hamstrings, which is responsible for an important muscle imbalance.

A Comparison of Two Models Predicting the Presence of Chronic Exertional Compartment Syndrome.

Clinical history and physical examination are usually not sufficient to diagnose leg chronic exertional compartment syndrome (CECS). Two predictive clinical models have been proposed. The first model by De Bruijn et al. is displayed as a nomogram that predicts the probability of CECS according to a risk score. The second model by Fouasson-Chailloux et al. combines two signs (post-effort muscle hardness on palpation or hernia). To evaluate those models, we performed a prospective study on patients who were referred for possible CECS. 201 patients underwent intra-compartmental pressure at 1-min post-exercise (CECS if ≥ 30 mmHg) - 115 had CECS. For the De Bruijn et al. model, the risk score was 7.5±2.2 in the CECS group and 4.6±1.7 in the non-CECS group (p<0.001) with an area under the ROC curve of 0.85. The model accuracy was 80% with a sensitivity of 82% and a specificity of 78%. Concerning Fouasson-Chailloux et al. model, the accuracy was 86%; the sensitivity and the specificity were 75 and 98%, respectively. The De Bruijn et al. model was a good collective model but less efficient in individual application. In patients having both muscle hardness and hernia, we could clinically make the diagnosis of CECS.

Impact of Patellar Tendinopathy on Isokinetic Knee Strength and Jumps in Professional Basketball Players.

Patellar tendinopathy is characterized by tendon pain which may reduce the level of performance. This study's main aim was to compare isokinetic knee strength and jump performances at the start of the sport season between players with patellar tendinopathy and those without. Secondary aims were to assess the relationship between knee strength and jump function. Sixty-two professional basketball players were enrolled (mean age: 25.0 ± 4.0). All players performed knee isokinetic measurements, single leg countermovement jumps, and one leg hop tests. Correlations between knee strength and jump performances were examined. Twenty-four players declared a patellar tendinopathy and were compared to the 38 players without tendinopathy. The isokinetic quadriceps strength was lower in cases of patellar tendinopathy, and a camel's back curve was observed in 58% of the cases of patellar tendinopathy. However, jump performances were preserved. No link was found between quadriceps and hamstring limb symmetry indexes at 60 and 180°/s with jumps. This preseason screening enabled us to identify the absence of consequences of patellar tendinopathy in professional basketball players. Jump performances were not altered, possibly due to compensatory strategies.

Hamstring Muscle Injury Prediction by Isokinetic Ratios Depends on the Method Used.

OBJECTIVES: Hamstring muscle injury prediction by isokinetic strength ratios is low but could result from the method-depending either on the use of the limbs or of the sportsmen as references. We aimed to establish a predictive model including unilateral and bilateral ratios calculated from the dominant, nondominant, right, and left limb in injured and uninjured professional soccer players. DESIGN: Cohort study. SETTING: Soccer team of the French Professional Premier League. PATIENTS: Ninety-one professional soccer players. INTERVENTIONS: Isokinetic muscle strength was prospectively measured at the beginning of 5 consecutive seasons (2009-2014). MAIN OUTCOME MEASURES: Several bilateral, conventional, and functional ratios were calculated from isokinetic measurements at different angular speeds (60 and 240 degrees/s in concentric mode and 30 degrees/s in eccentric mode). Thirty-one soccer players had a hamstring injury during the seasons and were compared with 60 uninjured players. Four models were tested to predict the occurrence of hamstring injury from isokinetic ratios calculated in accordance with the dominant, nondominant, right, and left limb. RESULTS: No predictive model was found when ratios were calculated from the dominant or the right limb. Two models of prediction were found when ratios were calculated from the nondominant or the left limb. In these 2 models, only the bilateral concentric hamstring-to-hamstring ratio at 60 degrees/s was predictive. The best prediction was found with the left limb. CONCLUSIONS: We identified 2 low predictive models for hamstring muscle injuries depending on the limbs studied. Because of a low prediction, the consensual method used to predict hamstring muscle injury must be defined in future studies.

Jumper's knee mechanical consequences in professional basketball players: the "Camel's Back curve".

PURPOSE: Jumper's knee is characterized by an anterior knee pain during tendon palpation and can be classified in overuse pathologies, secondary to repetitive jumps. The prevalence is high in professional basketball players. It is responsible for an alteration of the motor control inducing a strength deficit of the quadriceps. We aimed to describe an isokinetic curve anomaly, a double-humped curve called "Camel's Back curve", consequence of a jumper's knee history. METHODS: 170 Professional basketball players were enrolled (24.8 ± 4.6 years; 91.8 ± 12.0 kg, 194 ± 9.0 cm). All players performed isokinetic tests of the knee extensors on a concentric mode at the angular speed of 60°/s and 180°/s. RESULTS: 43 players had a jumper's knee history and 35 (81%) had a "Camel's Back curve" at 60°/s. The sensitivity and the specificity of this curve were 81.3% and 100%, respectively. The minimum torque of strength was decreased from 12 to 18% compared to the 2 maximal peaks. Yet, the strength measured every 5° of ROM was significantly different between the players with "Camel's Back curve" and those with normal curve. CONCLUSIONS: "Camel's Back curve" had never been described in that context. It may be secondary to a protective inhibitory mechanism which could alter jumping. The presence of a "Camel's Back curve" would enable clinicians to adapt physical preparation, knee rehabilitation, and trainings to improve players performances.

Diagnostic criteria of forearm Chronic Exertional Compartment Syndrome: A systematic review.

BACKGROUND: Chronic Exertional Compartment Syndrome (CECS) of the forearm is characterized by an increase of the pressure in the forearm compartments during repeated activities. Its diagnosis is challenging because of the lack of clearly established diagnostic criteria. PURPOSE: We aimed to provide a comprehensive description of the diagnostic methods used for CECS of the forearm, to assess if a more effective diagnosis strategy could be identified. METHODS: We used PubMed, Google Scholar, Cochrane Library and Science Direct databases to search articles. We carried out multiple searches using the mesh terms ("Chronic Exertional Compartment Syndrome" OR "Chronic compartment syndrome" OR "Exertional compartment") AND ("forearm" OR "upper limb"). Inclusion criteria were prospective or retrospective studies on CECS of the forearm including case reports. We used PRISMA guidelines. The included studies were critically appraised using GRADE approach. RESULTS: A total of 625 articles were screened and 33 studies were included. It represented 590 patients (505 men and 85 women), with a mean age of 26.6 years old. Among them, 282 competed at an elite level. Motorcycling and motocross were the most frequent sports (66%). Six diagnostic methods were employed. Intra-compartmental pressure (ICP) measurement was the most frequently used method in 26 studies. Magnetic resonance imaging was performed in 9 studies, while electromyography was employed in only 2 studies. One study reported the measurement of grip strength using a manual dynamometer, one study compared forearm circumference before and after effort, and one used myotonometry. Various exercise protocols were observed. Stress-testing using a hand-grip was the most common protocol in 14 studies. Exercise duration varied from 2 min to 60 min. CONCLUSION: Existing data do not provide sufficient evidence to favor an alternative diagnostic method over ICP measurements that should be used cautiously given the absence of formal validation. Non-invasive methods might be easier to use, but should be subjected to further research. LEVEL OF EVIDENCE: III.

Prolonged Physiotherapy after Anterior Cruciate Ligament Reconstruction Does Not Improve Muscular Strength and Function.

Background: After the rupture of the anterior cruciate ligament (ACL), surgery is proposed in the case of knee instability or for athletes who want to return to a pivotal and/or contact sport. The current trend is to extend physiotherapy sessions until a patient's return to sport. We aimed to assess the interest in prolonging the physiotherapy sessions up to 4 postoperative months to restore muscle knee strength and function. Methods: From a historical cohort, 470 patients (24.3 ± 8.7 years) were included; 312 (66%) were males. They all had undergone a primary ACL reconstruction with a hamstring procedure. The number of physiotherapy sessions was established at 4 postoperative months. The main study parameters to assess the benefit of prolonged physiotherapy were the isokinetic limb symmetry index (LSI) for the quadriceps and the hamstrings as well as the Lysholm score. Results: At 4 postoperative months, 148 patients (31.4%) still had physiotherapy sessions. This group had performed 49 ± 14 physiotherapy sessions at the time of evaluation compared to 33 ± 9 sessions performed by the group that stopped physiotherapy at 3 months post-ACL reconstruction. The isokinetic knee LSI and the Lysholm score were not different between the two groups. Continued physiotherapy sessions were associated with female gender, previous high sport level, meniscal repair, lateral tenodesis and outpatient rehabilitation at the beginning of the rehabilitation management, while knee pain complications were not associated. Conclusions: No significant correlation was found between the number of physiotherapy sessions and the knee strength LSI or the Lysholm score. Prolonging patient physiotherapy sessions after 3 months post-ACL reconstruction seems ineffective in improving knee strength recovery and function.

Arthrofibrosis risk factors after anterior cruciate ligament reconstruction.

Introduction: Knee arthrofibrosis is a disabling complication after anterior cruciate ligament reconstruction (ACLr). Different risk factors have been studied but are still controversial because of a diagnosis made only during reoperations for the treatment of the stiffness, which underestimates the occurrence rate. We aimed to confirm risk factors of arthrofibrosis after ACLr in case of clinically made diagnoses. Methods: Ninety-two athletes with clinically diagnosed arthrofibrosis, complicating a primary ACLr, were compared to 482 athletes with ACLr without any complications. Usually considered risk factors were studied: age under 18, female, Body Mass Index (BMI ≥ 25), high sport level, time from ACL injury to ACLr < 1 month, Bone-Patella-Tendon-Bone surgical procedure (BPTB), meniscal repair, and intensive rehabilitation. Binary logistic regression was carried out to confirm or refute these risk factors. Results: Female, time from ACL injury to ACLr < 1 month, BPTB procedure, meniscal repair, and BMI ≥ 25 were not confirmed as risk factors. Previous competitive sport level assessed by Tegner score was the only risk factor identified, OR: 3.56 (95%IC: 2.20-5.75; p = 0.0001). Age < 18, OR: 0.40 (95%IC: 0.19-0.84; p = 0.015) and inpatient rehabilitation program, OR: 0.28 (95%IC: 0.17-0.47; p = 0.0001), were protective factors. Discussion: Competitive athletes are at risk of arthrofibrosis after ACLr and should benefit from protective inpatient rehabilitation program.

Consequences of anterior knee pain after anterior cruciate ligament reconstruction: A 2015-2020 cohort study.

Anterior cruciate ligament reconstruction (ACLR) using hamstring tendon (HT) graft aims to stabilise the knee, but it may bring some complications like anterior knee (AKP) pain that can have consequences on the functional aspect of this surgery. The aim of this study was to compare isokinetic knee strength and functional outcomes between patients with and without AKP following an ACLR using HT graft during the first-year post-surgery. Three hundred and thirty subjects operated by ACLR using hamstring tendon graft were included in our retrospective cohort and divided into two groups: a group with AKP (AKP+ group) and one without AKP (AKP-group). In our population, 14.8% of the patients had AKP. At 4 post-operative months, subjects with pain had lower isokinetic strength limb symmetry index (LSI) for knee flexors and extensors, and a lower Lysholm score than subjects without pain (p < 0.0001). These differences did not persist at 7 post-operative months, and there was no difference in the one-leg hop test. After multivariate analysis, we highlighted the impact of time on the evolution of these parameters. Yet, the exact definition of AKP after ACLR remains to be clearly defined since an imprecise diagnosis may lead to inappropriate management. Pre-operative information about this type of complication, which evolves favourably with time, could be useful for patients. Indeed, AKP can occur after ACLR, even if a HT graft has been used, compared to other surgical procedures using the knee extensor apparatus as patellar tendon graft (AKP is associated with the donor site morbidity). In case of AKP after ACLR, monitoring the muscle inhibition by isokinetic tests may enable clinicians to adapt the retraining and the return to sport.

Congenital anomalous origin of a single coronary artery and high-level sporting competition.

Using a single clinical case of a professional soccer player presenting an anomalous origin of the right coronary artery, cardiac screening and surgical treatment are described taking into account the recommendations of cardiac and sports societies.

Lower-Limb Arthropathies and Walking: The Use of 3D Gait Analysis as a Relevant Tool in Clinical Practice.

Arthropathy refers to the notion of joint diseases [...].

Arthrogenic muscle inhibition and return to sport after arthrofibrosis complicating anterior cruciate ligament surgery.

Arthrofibrosis is a devastating complication after Anterior Cruciate Ligament reconstruction (ACLr) characterized by a muscle weakness secondary to an arthrogenic muscle inhibition process. The loss of knee isokinetic strength due to arthrogenic muscle inhibition may be more important after arthrofibrosis, compared to an ACLr population with no complication. The isokinetic strength deficit [Limb Symmetry Index (LSI) at 60 and 180°/s of angular speed] was measured at 4, 7 and 12 post-operative months. Knee function, return to running and return to sport were evaluated. A comparison of the Quadriceps and the Hamstring LSI between patients with arthrofibrosis and those without post-operative complication was performed according to time and taking into consideration the type of surgical procedure. 539 primary ACLr patients were assessed. The arthrofibrosis group presented at 4, 7 and 12 post-operative months a Quadriceps LSI significantly lower compared to the control group, without influence of the graft procedure (LSI: 38, 53, 68% vs 63, 73, 85% at 60°/s, respectively). The Hamstring LSI was significantly lower at 4 and 7 post-operative months, but comparable at 12 months with an influence of the Hamstring procedure. Knee function was significantly lower at 4 and 7 post-operative months. Few arthrofibrosis ACLr patients returned to running at 7 post-operative months (6.8% vs 69.9%; p < .0001). An important and durable Quadriceps muscle weakness occurred after arthrofibrosis, whatever the type of graft procedure. This is explained by an Arthrogenic muscle inhibition which compromised the return to sport at the same level until 12 post-operative months.HighlightsAn important and durable quadriceps muscle weakness occurred after arthrofibrosis.The arthrogenic muscle inhibition was significant on the operated side independently of the type of the graft procedure.Arthrogenic muscle inhibition compromised the return to sport at the same level until 12 post-operative months.

Social Media in Health Studies: A Systematic Review of Comparative Learning Methods.

Learning modifications particularly increased due to the SARS-CoV-2 pandemic, which made it necessary to offer distance health education for many months. Social media allows students to have interactive activities such as discussing specific subjects or sharing data with each other, and also to have interactions with their teachers and tutors. So, we aimed to compare the effects of the use of social media on knowledge, skills and perceptions in health students compared to other methods. We performed a systematic review on PubMed, ScienceDirect and Embase about comparative learning methods using social media. The search followed PRISMA guidelines, and the quality assessment of the studies was performed using the Medical Education Research Quality instrument (MERSQI). Eight studies were analyzed including 1014 participants. Mean age ranged from 19.9 to 23.4 years, and 70% were females. About 54.4% of the participants were medical students and 20.9% were dental students. The mean MERSQI was 11.7 ± 2.6. Various subjects were included-anatomy, cultural competences, sterile surgical techniques, radiology, arthrocentesis, medical pathologies and cariology. As far as knowledge evaluation was concerned, we found that the use of social media may have had a positive effect from a short-term point of view but results concerning skills were less consistent across studies. Students usually had a positive perception of the use of social media as a complementary method but not as a complete alternative so it is not excluded that this effect might result from an increase in working time. The impact on patient care should also be assessed in future studies.

Isokinetic quadriceps symmetry helps in the decision to return to running after anterior cruciate ligament reconstruction.

BACKGROUND: After anterior cruciate ligament reconstruction (ACLR), the decision to allow a return to running is empirical, and the post-operative delay is the most-used criterion. The Quadriceps isokinetic-strength Limb Symmetry Index (Quadriceps LSI), with a cutoff of 60%, could be a useful criterion. OBJECTIVE: To determine the association between a Quadriceps LSI≥60% and return to running after ACLR. METHODS: Over a 10-year period, we retrospectively included 470 patients who underwent ACLR. Four months after ACLR, participants performed an isokinetic test; quadriceps concentric peak torque was used to calculate the Quadriceps LSI at 60̊/s. With a Quadriceps LSI≥60%, a return to running was suggested. At 6 months after ACLR, participants were clinically evaluated for a return to sport and post-operative middle-term complications. A multivariable predictive model was built to assess the efficiency diagnosis of this cutoff in order to consider cofounding factors. Quadriceps LSI cutoff≥60% was assessed with sensitivity, specificity and the area under the receiver operating characteristic curve (AUC). RESULTS: According to our decision-making process with the 60% Quadriceps LSI cutoff at 60̊/s, 285 patients were authorized to return to running at 4 months after ACLR and 185 were not, but 21% (n=59) and 24% (n=45), respectively, were not compliant with the recommendation. No iterative autograft rupture or meniscus pathology occurred at 6 months of follow-up. On multivariable logistic regression analysis, a return to running by using the 60% Quadriceps LSI cutoff was associated with undergoing the hamstring strand procedure (odds ratio 2.60, 95% confidence interval [CI] 1.75-3.84; P<0.0001) and the absence of knee complications (1.18, 1.07-1.29; P=0.001) at 4 months. The sensitivity and specificity of the 60% Quadriceps LSI cutoff were 83% and 70%, respectively. The AUC was 0.840 (95% CI 0.803-0.877). CONCLUSIONS: Using the 60% cutoff of the isokinetic Quadriceps LSI at 4 months after ACLR could help in the decision to allow a return to running.

Anatomical and Neuromuscular Factors Associated to Non-Contact Anterior Cruciate Ligament Injury.

The majority of anterior cruciate ligament (ACL) injuries occur during non-contact mechanisms. Knowledge of the risk factors would be relevant to help prevent athletes' injuries. We aimed to study risk factors associated with non-contact ACL injuries in a population of athletes after ACL reconstruction. From a cohort of 307 athletes, two populations were compared according to the non-contact or contact mechanism of ACL injury. Gender, age and body mass index (BMI) were reported. Passive knee alignment (valgus and extension), knee laxity (KT-1000 test), and isokinetic knee strength were measured on the non-injured limb. The relationship between these factors and the non-contact sport mechanism was established with models using logistic regression analysis for the population and after selection of gender and cut-offs of age, BMI and knee laxity calculated from Receiver Operating Characteristics curve area and Youden index. Age, BMI, antero-posterior laxity, isokinetic knee strength, passive knee valgus and passive knee extension were associated with non-contact ACL injury. According to the multivariate model, a non-contact ACL injury was associated with non-modifiable factors, age (OR: 1.05; p = 0.001), passive knee extension (OR: 1.14; p = 0.001), and with one modifiable factor (Hamstring strength: OR: 0.27; p = 0.01). For women, only passive knee valgus was reported (OR: 1.27; p = 0.01). Age, passive knee extension and weak Hamstring strength were associated with a non-contact ACL injury. Hamstring strengthening could be proposed to prevent ACL injury in young male athletes or in case of knee laxity.