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.

After anterior cruciate ligament reconstruction (ACLR), a progressive process is followed from rehabilitation to the return to sport including a crucial step known as the return to running. Return to running (RTR) can be predicted by an isokinetic knee strength assessment at 4 months post-surgery. All patients who had primarily undergone ACLR with a hamstring autograft procedure between 2010 and 2020 were included in this study. Four months after surgery, patients were evaluated using an isokinetic knee strength test. Patients were monitored until the 6th month post-surgery to see if they had returned to running. Comparisons were carried out between the two groups—the RTR and the no-RTR. A multivariate logistic regression analysis was used to predict the RTR status from explicative parameters. Receiver Operating Characteristic (ROC) curves were established to identify cutoffs with their characteristics. A total of 413 patients were included and 63.2% returned to running at 4 months post-surgery. The mean Lysholm score, knee complication rate, and isokinetic parameters were statistically different between both groups. Using a multivariate logistic regression model and ROC curves, the best isokinetic parameter to assist with the decision to allow an RTR was the quadriceps limb symmetry index at 60°/s with a cutoff of 65%. The hamstring LSI at 180°/s could be added (cutoff of 80%) to slightly increase the prediction of an RTR. Quadriceps strength normalized to body weight at 60°/s is a useful parameter (cutoff: 1.60 Nm/kg) but measurements on both sides are necessary. Isokinetic parameters are objective parameters to allow a return to running at 4 months after ACLR with a hamstring procedure.

Periprosthetic joint infections (PJI) occur in 0.5 to 2.8% of total knee arthroplasties (TKA) and expose them to an increase of morbidity and mortality. TKA are mainly performed after failure of non-surgical management of knee osteoarthritis, which frequently includes intra-articular injections of corticosteroids or hyaluronic acid. Concerning the potential impact of intra-articular injections on TKA infection, literature provides a low level of evidence because of the retrospective design of the studies and their contradictory results. In this prospective cohort study, we included patients after a total knee arthroplasty, at the time of their admission in a rehabilitation center, and we excluded patients with any prior knee surgery. 304 patients were included. Mean follow-up was 24.9 months, and incidence proportion of PJI was 2.6%. After multivariate logistic regression, male was the only significant risk factor of PJI (OR = 19.6; p = 0.006). The incidence of PJI did not differ between patients who received prior intra-articular injections and others, especially regarding injections in the last 6 months before surgery. The use of intra-articular injection remains a valid therapeutic option in the management of knee osteoarthritis, and a TKA could still be discussed.

The COVID-19 pandemic required local confinement measures reducing sport practice with possible consequences on the athletes’ performances. Furthermore, anaerobic detraining was underestimated and poorly known in adolescents. This article aimed to assess the effects of SARS-CoV-2 infection and 1-month COVID-19 confinement on jump testing in young elite soccer players despite a 1-month multimodal training program followed by a 1-month soccer retraining period. Thirty-one elite soccer players aged 14 were included; 16 were infected by the SARS-CoV-2 and compared with 15 non-infected elite soccer players before and after 1 month of COVID-19 confinement, and after 1 month of a soccer retraining period. Squat jumps (SJ), countermovement jumps with (CMJs) and without arm swinging (CMJ) and multiple consecutive jumps (stiffness) were used to explore the anaerobic performances. Analysis of variance for repeated measures was used to compare the positive and negative SARS-CoV-2 groups, taking into account the confinement period (low training) and the retraining soccer period. The jump tests were not altered in the positive SARS-CoV-2 group compared to the negative SARS-CoV-2 group after confinement (SJ: 31.6 ± 5.6 vs. 32.7 ± 3.7; CMJ: 34.1 ± 6.9 vs. 34.2 ± 2.6; CMJs: 38.6 ± 6.8 vs. 40.3 ± 3.9; stiffness: 28.5 ± 4.3 vs. 29.1 ± 3.7) and at 1 month of this period (SJ: 33.8 ± 5.5 vs. 36.2 ± 4.6; CMJ: 34.7 ± 5.5 vs. 36.4 ± 3.5; CMJs: 40.4 ± 6.7 vs. 42.7 ± 5.5; stiffness: 32.6 ± 4.7 vs. 34.0 ± 4.3). The SARS-CoV-2 infection had no consequence on anaerobic performances assessed by jump tests in adolescent soccer players. The adolescents’ growth could explain the absence of alteration of jump performances during the COVID-19 confinement. These results can be useful to manage the recovery of the anaerobic fitness after SARS-CoV-2 infection occurring in adolescent athletes.

Background and objectives: Muscle knee strength is a major parameter that allows return to running. Isokinetic strength parameters may predict return to running 4 months after ACLR using the bone–patellar–tendon–bone procedure. Materials and methods: The isokinetic knee strength of 216 patients (24.5 ± 5 years) was measured 4 months after surgery, and progressive return to running was allowed. The effectiveness of return to running was reported at 6 months. Return to running prediction was established using multivariate logistic regression. Predictive parameters were presented with a ROC curve area to define the best cut-off, with sensibility (Se) and specificity (Sp). Results: A model was established, including the limb symmetry index (LSI), and 103 patients (47.6%) were able to run between the fourth and the sixth month after surgery. These patients presented significantly fewer knee complications, a better Lysholm score, a better Quadriceps and Hamstring LSI and better quadriceps strength reported for body weight on the operated limb. The best model was established including the Quadriceps and Hamstring LSI at 60°/s and the Lysholm score. The cut-off for Quadriceps LSI was 60% (ROC curve area: 0.847; Se: 77.5%; Sp: 77%), for Hamstring LSI 90% (ROC curve area: 0.716; Se: 65.7%; Sp: 60.2%) and for Lyshom score 97 points (ROC curve area: 0.691; Se: 65%; Sp: 66%). Conclusion: Four months after ACLR using a bone–patellar–tendon–bone procedure, the Quadriceps and Hamstring LSI associated to the Lysholm score could help make the decision to allow return to running.

Therapeutic education aims to help patients acquire skills and knowledge, and to improve psychosocial aspects to manage chronic disease. After anterior cruciate ligament reconstruction (ACLR), only 35 to 60% of the patients are able to go back to their previous sport. Return to sport depends on the motivation of the patient. No therapeutic education has already been proposed. We aimed to evaluate the effect of therapeutic education sessions on knowledge improvement during inpatient rehabilitation after ACLR, compared to patients operated with the same surgical technic, but who had no therapeutic education because of outpatient rehabilitation. Sessions were performed by a multidisciplinary team. The evaluation of the knowledge was performed with a true or false 12-items self-report questionnaire. Fifty-four patients were studied and compared to 54 patients with no therapeutic education. The educated and the non-educated groups were comparable. The number of correct answers increased from 73% before therapeutic education to 95% at the end of the hospitalization (p < 0.001). This improvement persisted over time with 91.5% of correct answers at four months (p = 0.94). The non-educated group had 70% of correct answers. This was significantly lower than the results obtained from the educated group at four months (p < 0.001). It was comparable to the result obtained before therapeutic education (p = 0.91). Therapeutic patient education performed during hospitalization for rehabilitation enables patients to have a better knowledge of the stages from rehabilitation to return to sport and the risks of complication after ACLR.