The aim of the present study was to quantify joint kinematics through a wearable sensor system in multidirectional high-speed complex movements used in a protocol for rehabilitation and return to sport assessment after Anterior Cruciate Ligament (ACL) injury, and to validate it against a gold standard optoelectronic marker-based system. Thirty-four healthy athletes were evaluated through a full-body wearable sensor (MTw Awinda, Xsens) and a marker-based optoelectronic (Vicon Nexus, Vicon) system during the execution of three tasks: drop jump, forward sprint, and 90° change of direction. Clinically relevant joint angles of lower limbs and trunk were compared through Pearson’s correlation coefficient (r), and the Coefficient of Multiple Correlation (CMC). An excellent agreement (r > 0.94, CMC > 0.96) was found for knee and hip sagittal plane kinematics in all the movements. A fair-to-excellent agreement was found for frontal (r 0.55–0.96, CMC 0.63–0.96) and transverse (r 0.45–0.84, CMC 0.59–0.90) plane kinematics. Movement complexity slightly affected the agreement between the systems. The system based on wearable sensors showed fair-to-excellent concurrent validity in the evaluation of the specific joint parameters commonly used in rehabilitation and return to sport assessment after ACL injury for complex movements. The ACL professionals could benefit from full-body wearable technology in the on-field rehabilitation of athletes.

Modifiable (biomechanical and neuromuscular) anterior cruciate ligament (ACL) injury risk factors have been identified in laboratory settings. These risk factors were subsequently used in ACL injury prevention measures. Due to the lack of ecological validity, the use of on‐field data in the ACL injury risk screening is increasingly advocated. Though, the kinematic differences between laboratory and on‐field settings have never been investigated. The aim of the present study was to investigate the lower‐limb kinematics of female footballers during agility movements performed both in laboratory and football field environments. Twenty‐eight healthy young female talented football (soccer) players (14.9 ± 0.9 years) participated. Lower‐limb joint kinematics was collected through wearable inertial sensors (Xsens Link) in three conditions: (1) laboratory setting during unanticipated sidestep cutting at 40‐50°; on the football pitch (2) football‐specific exercises (F‐EX) and (3) football games (F‐GAME). A hierarchical two‐level random effect model in Statistical Parametric Mapping was used to compare joint kinematics among the conditions. Waveform consistency was investigated through Pearson's correlation coefficient and standardized z‐score vector. In‐lab kinematics differed from the on‐field ones, while the latter were similar in overall shape and peaks. Lower sagittal plane range of motion, greater ankle eversion, and pelvic rotation were found for on‐field kinematics (p < 0.044). The largest differences were found during landing and weight acceptance. The biomechanical differences between lab and field settings suggest the application of context‐related adaptations in female footballers and have implications in ACL injury prevention strategies.Highlights Talented youth female football players showed kinematical differences between the lab condition and the on‐field ones, thus adopting a context‐related motor strategy. Lower sagittal plane range of motion, greater ankle eversion, and pelvic rotation were found on the field. Such differences pertain to the ACL injury mechanism and prevention strategies. Preventative training should support the adoption of non‐linear motor learning to stimulate greater self‐organization and adaptability. It is recommended to test football players in an ecological environment to improve subsequent primary ACL injury prevention programmes.

Purpose: Abnormal joint biomechanics and poor neuromuscular control are modifiable risk factors for Anterior Cruciate Ligament (ACL) injury. Although 3D motion capture is the gold standard for the biomechanical evaluation of high‐speed multidirectional movements, 2D video analysis is a growing‐interest alternative because of its higher cost‐effectiveness and interpretability. The aim of the present study was to explore the possible association between a 2D evaluation of a 90° change of direction (COD) and the KAM measured with gold standard 3D motion analysis.Methods: Thirty‐four competitive football (soccer) players (age 22.8 ± 4.1, 18 male and 16 females) were enrolled. Each athlete performed a series of pre‐planned 90° COD at the maximum speed possible in a laboratory equipped with artificial turf. 3D motion analysis was recorded using 10 stereophotogrammetric cameras, a force platform, and three high‐speed cameras. The 2D evaluation was performed through a scoring system based on the video analysis of frontal and sagittal plane joint kinematics. Five scoring criteria were adopted: limb stability (LS), pelvis stability (PS), trunk stability (TS), shock absorption (SA), and movement strategy (MS). For each criterion, a sub‐score of 0/2 (non‐adequate), 1/2 (partially adequate), or 2/2 (adequate) was attributed to the movement, based on objective measurements. The intra‐rater and inter‐rater reliability were calculated for each criterion and the total score. The Knee Abduction Moment (KAM) was extracted from the 3D motion analysis and grouped according to the results of the 2D evaluation.Results: Excellent intra‐rater reliability (ICC > 0.88) and good‐to‐excellent inter‐rater reliability (ICC 0.68–0.92) were found. Significantly higher KAM was found for athletes obtaining a 0/2 score compared to those obtaining a 2/2 score in all the sub‐criteria and the total score (20–47% higher, p < 0.05). The total score and the LS score showed the best discriminative power between the three groups.Conclusion: The 2D video‐analysis scoring system here described was a simple and effective tool to discriminate athletes with high and low KAM in the assessment of a 90° COD and could be a potential method to identify athletes at high risk of non‐contact ACL injury.Level of evidence: IV.

Radiofrequency (RF) is a minimally invasive procedure used to interrupt or alter nociceptive pathways for treating musculoskeletal pain. It seems a useful tool to relieve chronic pain syndromes, even if, to date, solid evidence is still needed about the effectiveness of this therapy. By this systematic review and meta-analysis, we aimed to evaluate the efficacy of RF in treating musculoskeletal pain. PubMed, Medline, Cochrane, and PEDro databases were searched to identify randomized controlled trials (RCTs) presenting the following: patients with chronic musculoskeletal pain as participants; RF as intervention; placebo, anesthetic injection, corticosteroid injection, prolotherapy, conservative treatment, physiotherapy, and transcutaneous electrical nerve stimulation as comparisons; and pain and functioning as outcomes. Continuous random-effect models with standardized mean difference (SMD) were used to compare the clinical outcomes. Overall, 26 RCTs were eligible and included in the systematic review. All of them analyzed the efficacy of RF in four different regions: cervical and lumbar spine, knee, sacroiliac (SI) joint, shoulder. The outcomes measures were pain, disability, and quality of life. A medium and large effect in favor of the RF treatment group (SMD < 0) was found for the shoulder according to the Visual Analogical Scale and for the SI joint according to the Oswestry Disability Index. A small effect in favor of the RF treatment group (SMD > 0) was found for the spine according to the 36-item Short Form Survey. Non-significant SMD was found for the other outcomes. RF represents a promising therapy for the treatment of chronic musculoskeletal pain, especially when other approaches are ineffective or not practicable. Further studies are warranted to better deepen the effectiveness of RF for pain and joint function for each anatomical region of common application.

Importance Meniscal tears are frequently associated with anterior cruciate ligament (ACL) injury and the correct management of this kind of lesion during ACL-reconstruction procedure is critical for the restoration of knee kinematics. Although the importance of meniscus in knee biomechanics is generally accepted, the influence of medial and lateral meniscus in stability of ACL-deficient knee is still unclear. Objective The aim of this study was to review literature, which analysed effects in cadaveric specimens of meniscal tear and meniscectomy of medial and lateral meniscus on laxity in the ACL-deficient knee. Evidence review Authors performed a systematic search for cadaveric studies analysing the effect of medial and lateral meniscus tears or resection on kinematics of ACL-deficient knee. Extracted data included year of publications, number of human cadaver knee specimens, description of apparatus testing and instrumented kinematic evaluation, testing protocol and results. Findings Authors identified 18 studies that met inclusion and exclusion criteria of current review. The major finding of the review was that the works included reported a difference role of medial and lateral meniscus in restraining ACL-deficient knee laxity. Medial meniscus tear or resection resulted in a significant increase of anterior tibial displacement. Lateral meniscus lesions or meniscectomy on the other hand significantly increased rotation and translation under a coupled valgus stress and internal-rotation torque/pivot shift test. Conclusions Medial and lateral meniscus have a different role in stabilising the ACL-deficient knee: while the medial meniscus functions as a critical secondary stabilisers of anterior tibial translation under an anterior/posterior load, lateral meniscus appears to be a more important restraint of rotational and dynamic laxity. Level of evidence Level IV, systematic review of level I–IV studies.