In 1992 van Mechelen et al published a “sequence of prevention model” based on a four-step process. This model has been widely used to implement preventive measures in response to sports injuries. However, the execution of this model has been shown to lack validity in determining the success of a preventive measure. A modified model has therefore been proposed which incorporates additional steps that enable the inclusion of external factors with a significant effect on the outcome of a prevention intervention. This expansion of van Mechelen’s model leads to a more global model in which the compliance level and risk-taking behaviour of the individual and the assessment of efficiency of the stakeholders have a key influence on the preventive measure. This model gives a better insight into the different processes in injury prevention that can be used by clinicians, coaches and managers to decide whether to implement a preventive measure programme.

Delayed onset of vastus medialis obliquus activity has been described in patellofemoral pain patients. No prospective study investigating the development of patellofemoral pain has tested the onset timing of electromyographic activity of the vastus medialis obliquus and vastus lateralis muscles during a functional task. Before the development of patellofemoral pain, subjects demonstrate an altered firing order of the vastus medialis obliquus and vastus lateralis muscles compared with healthy subjects during a functional task. Cohort study; Level of evidence, 2. The onset of vastus medialis obliquus and vastus lateralis activity was measured with surface electromyography during a functional task (rocking back on the heels) in 79 healthy subjects subsequently submitted to a 6-week strenuous basic military training. Afterward, these subjects were reassessed. Thirty-two percent of the recruits developed patellofemoral pain during training. Patellofemoral pain subjects demonstrated a significant delay of onset of vastus medialis obliquus electromyographic activity compared with the healthy controls (P = .023), even before basic military training. In healthy subjects, no significant differences in electromyographic activity onset of the vastus medialis obliquus compared with the vastus lateralis could be identified before and after basic military training. A significant (P < .001) delay could be demonstrated in the patellofemoral pain group after basic military training. A binary logistic regression could be constructed wherein the onset of the electromyographic activity of the vastus medialis obliquus and vastus lateralis was withheld in the model. The most optimal cutoff value, which is based on the receiver operating characteristic curve, is a timing difference of −0.67 milliseconds (vastus medialis obliquus – vastus lateralis). The area under the receiver operating characteristic curve is considered as fair (0.68). Delayed onset of electromyographic activity of the vastus medialis obliquus–vastus lateralis is one of the contributing risk factors to the development of patellofemoral pain.

Objectives: To explore the role of muscular strength and imbalance as predisposing factors in the development of anterior knee pain syndrome(AKPS). Methods: 96 male military recruits without history of knee pain volunteered for the study. Each volunteer underwent an isokinetic test prior to the start of a strenuous training program (approximately 8 to 12 hours/day for 6 weeks). The isokinetic test consisted of concentric contractions of the knee flexors and extensors at 60°/s and 240°/s. A detailed history and clinical examination of the patellofemoral joint was performed on each recruit. Independent sample t-tests were used to compare the isokinetic muscle parameters in recruits who developed AKPS during the training (pathological group) and in those who did not (control group). Binary logistic regression analysis was used to define the predictive outcome of anthropometrics and the isokinetic parameters for the development of AKPS. Results: 31 recruits developed AKPS. Absolute and bodyweight normalized peak extensor torque at 60°/s was significantly lower in the pathological group in comparison to the control group. Significant lower peak torque/BMI (Body Mass Index) were also indicated at both velocities. Recruits who developed AKPS had a shorter stature. No regression model could be set up to give any predictive value to the analyzed parameters. Conclusions: Recruits with shorter stature and lower quadriceps strength are more prone to develop AKPS during BMT. However, as the etiology of AKPS is multifactorial these parameters alone may not suffice to predict the occurrence of this pathology. On the other hand, the results of this study emphasize the importance of the reinforcement of quadriceps strength in the treatment and prevention of AKPS.

This study aims to measure and compare spatiotemporal gait parameters in nineteen subjects using a full wearable inertial mocap system Xsens (MVN Awinda, Netherlands) and a photoelectronic system one-meter OptoGait^TM (Microgait, Italy) on a treadmill imposing a walking speed of 5 km/h. A total of eleven steps were considered for each subject constituting a dataset of 209 samples from which spatiotemporal parameters (SPT) were calculated. The step length measurement was determined using two methods. The first one considers the calculation of step length based on the inverted pendulum model, while the second considers an anthropometric approach that correlates the stature with an anthropometric coefficient. Although the absolute agreement and consistency were found for the calculation of the stance phase, cadence and gait cycle, from our study, differences in SPT were found between the two systems. Mean square error (MSE) calculation of their speed (m/s) with respect to the imposed speed on a treadmill reveals a smaller error (MSE = 0.0008) using the OptoGait^TM. Overall, our results indicate that the accurate detection of heel strike and toe-off have an influence on phases and sub-phases for the entire acquisition. Future study in this domain should investigate how to design and integrate better products and algorithms aiming to solve the problematic issues already identified in this study without limiting the user’s need and performance in a different environment.

Background: The current gold standard for the treatment of an anterior cruciate ligament (ACL) rupture is reconstruction with tendon graft. Recently, two surgical ACL repair techniques have been developed for treating an acute ACL rupture: Dynamic Intraligamentary Stabilization (DIS, Ligamys®) and Internal Brace Ligament Augmentation (IBLA,InternalBrace™). We will conduct a single-blind, multi-center, randomized controlled trial which compares DIS, IBLA and reconstruction for relative clinical efficacy and economic benefit.Methods: Subjects, aged 18–50 years, with a proximal, primary and repairable ACL rupture will be included. DIS is preferably performed within 4 weeks post-rupture, IBLA within 12 weeks and reconstruction after 4 weeks post-rupture. Patients are included in study 1 if they present within 0–4 weeks post-rupture and surgery is feasible within 4 weeks post-rupture. Patients of study 1 will be randomized to either DIS or IBLA. Patients are included in study 2 if they present after 4 weeks post-rupture and surgery is feasible between 5 and 12 weeks post-rupture. Patients of study 2 will be randomized to either IBLA or reconstruction. A total of 96 patients will be included, with 48 patients per study and 24 patients per study arm. Patients will be followed-up for 2 years. The primary outcome is change from baseline (pre-rupture) in International Knee Documentation Committee score to 6 months post-operatively. The main secondary outcomes are the EQ-5D-5 L, Tegner score, Lysholm score, Lachman test, isokinetic and proprioceptive measurements, magnetic resonance imaging outcome, return to work and sports, and re-rupture/failure rates. The statistical analysis will be based on the intention-to-treat principle. The economic impact of the surgery techniques will be evaluated by the cost-utility analysis. The LIBRƎ study is to be conducted between 2018 and 2022.Discussion: This LIBRƎ study protocol is the first study to compare DIS, IBLA and ACL reconstruction for relative clinical efficacy and economic benefit. The outcomes of this study will provide data which could aid orthopaedic surgeons to choose between the different treatment options for the surgical treatment of an acute ACL rupture.Trial registration: This study is registered at ClinicalTrials.gov;NCT03441295. Date registered 13.02.2018.

It has been shown that muscle fatigue has a negative influence on proprioception. Several studies already have demonstrated improvement of proprioception by using knee sleeves. Neoprene knee sleeves have different effects on the joint position sense in locally fatigued subjects with good or poor proprioceptive acuity. A true experimental design with random assignment to intervention and control limbs. Military hospital, department of physical medicine and rehabilitation. Sixty-four healthy subjects. All subjects underwent four consecutive assessments of the same active joint-repositioning test under different conditions (braced, nonbraced, fatigued, and nonfatigued). A three-way analysis of variance with repeated-measures design was conducted to investigate the effects of side (braced versus control side), assessment sequence (one to four), and proprioceptive acuity ("good" versus "poor"), and their interactive effect on the joint position sense. Post hoc analysis revealed that only subjects with "poor" proprioceptive acuity benefit from the braced condition before the isokinetic fatigue protocol (P < 0.001). In contrast, all subjects benefit from the braced condition after the fatigue test. Bracing is helpful in individuals with a poor baseline proprioceptive acuity in both fatigued and nonfatigued states. Subjects with a good joint position sense benefit from bracing only when in a fatigued state. The present findings suggest a rationale for using neoprene knee sleeves as a preventative measure or treatment in subjects and patients to enhance proprioceptive acuity in a fatigued state. Classification into "poor" and "good" proprioceptive acuity is only relevant in the nonfatigued condition.