Randomised controlled trials (RCTs) in sports injury research: authors-please report the compliance with the intervention.

BACKGROUND: In randomised controlled trials (RCTs) of interventions that aim to prevent sports injuries, the intention-to-treat principle is a recommended analysis method and one emphasised in the Consolidated Standards of Reporting Trials (CONSORT) statement that guides quality reporting of such trials. However, an important element of injury prevention trials-compliance with the intervention-is not always well-reported. The purpose of the present educational review was to describe the compliance during follow-up in eight large-scale sports injury trials and address compliance issues that surfaced. Then, we discuss how readers and researchers might consider interpreting results from intention-to-treat analyses depending on the observed compliance with the intervention. METHODS: Data from seven different randomised trials and one experimental study were included in the present educational review. In the trials that used training programme as an intervention, we defined full compliance as having completed the programme within ±10% of the prescribed running distance (ProjectRun21 (PR21), RUNCLEVER, Start 2 Run) or time-spent-running in minutes (Groningen Novice Running (GRONORUN)) for each planned training session. In the trials using running shoes as the intervention, full compliance was defined as wearing the prescribed running shoe in all running sessions the participants completed during follow-up. RESULTS: In the trials that used a running programme intervention, the number of participants who had been fully compliant was 0 of 839 (0%) at 24-week follow-up in RUNCLEVER, 0 of 612 (0%) at 14-week follow-up in PR21, 12 of 56 (21%) at 4-week follow-up in Start 2 Run and 8 of 532 (1%) at 8-week follow-up in GRONORUN. In the trials using a shoe-related intervention, the numbers of participants who had been fully compliant at the end of follow-up were 207 of 304 (68%) in the 21 week trial, and 322 of 423 (76%), 521 of 577 (90%), 753 of 874 (86%) after 24-week follow-up in the other three trials, respectively. CONCLUSION: The proportion of runners compliant at the end of follow-up ranged from 0% to 21% in the trials using running programme as intervention and from 68% to 90% in the trials using running shoes as intervention. We encourage sports injury researchers to carefully assess and report the compliance with intervention in their articles, use appropriate analytical approaches and take compliance into account when drawing study conclusions. In studies with low compliance, G-estimation may be a useful analytical tool provided certain assumptions are met.

Time-to-event analysis for sports injury research part 1: time-varying exposures.

BACKGROUND: 'How much change in training load is too much before injury is sustained, among different athletes?' is a key question in sports medicine and sports science. To address this question the investigator/practitioner must analyse exposure variables that change over time, such as change in training load. Very few studies have included time-varying exposures (eg, training load) and time-varying effect-measure modifiers (eg, previous injury, biomechanics, sleep/stress) when studying sports injury aetiology. AIM: To discuss advanced statistical methods suitable for the complex analysis of time-varying exposures such as changes in training load and injury-related outcomes. CONTENT: Time-varying exposures and time-varying effect-measure modifiers can be used in time-to-event models to investigate sport injury aetiology. We address four key-questions (i) Does time-to-event modelling allow change in training load to be included as a time-varying exposure for sport injury development? (ii) Why is time-to-event analysis superior to other analytical concepts when analysing training-load related data that changes status over time? (iii) How can researchers include change in training load in a time-to-event analysis? and, (iv) Are researchers able to include other time-varying variables into time-to-event analyses? We emphasise that cleaning datasets, setting up the data, performing analyses with time-varying variables and interpreting the results is time-consuming, and requires dedication. It may need you to ask for assistance from methodological peers as the analytical approaches presented this paper require specialist knowledge and well-honed statistical skills. CONCLUSION: To increase knowledge about the association between changes in training load and injury, we encourage sports injury researchers to collaborate with statisticians and/or methodological epidemiologists to carefully consider applying time-to-event models to prospective sports injury data. This will ensure appropriate interpretation of time-to-event data.

Time-to-event analysis for sports injury research part 2: time-varying outcomes.

BACKGROUND: Time-to-event modelling is underutilised in sports injury research. Still, sports injury researchers have been encouraged to consider time-to-event analyses as a powerful alternative to other statistical methods. Therefore, it is important to shed light on statistical approaches suitable for analysing training load related key-questions within the sports injury domain. CONTENT: In the present article, we illuminate: (i) the possibilities of including time-varying outcomes in time-to-event analyses, (ii) how to deal with a situation where different types of sports injuries are included in the analyses (ie, competing risks), and (iii) how to deal with the situation where multiple subsequent injuries occur in the same athlete. CONCLUSION: Time-to-event analyses can handle time-varying outcomes, competing risk and multiple subsequent injuries. Although powerful, time-to-event has important requirements: researchers are encouraged to carefully consider prior to any data collection that five injuries per exposure state or transition is needed to avoid conducting statistical analyses on time-to-event data leading to biased results. This requirement becomes particularly difficult to accommodate when a stratified analysis is required as the number of variables increases exponentially for each additional strata included. In future sports injury research, we need stratified analyses if the target of our research is to respond to the question: 'how much change in training load is too much before injury is sustained, among athletes with different characteristics?' Responding to this question using multiple time-varying exposures (and outcomes) requires millions of injuries. This should not be a barrier for future research, but collaborations across borders to collecting the amount of data needed seems to be an important step forward.

Physical activity promotion in primary care: a Utopian quest?

The health benefits of physical activity (PA) are acknowledged and promoted by the scientific community, especially within primary care. However, there is little evidence that such promotion is provided in any consistent or comprehensive format. Brief interventions (i.e. discussion, negotiation or encouragement) and exercise referral schemes (i.e. patients being formally referred to a PA professional) are the two dominant approaches within primary care. These cost-effective interventions can generate positive changes in health outcomes and PA levels in inactive patients who are at increased risk for non-communicable diseases. Their success relies on the acceptability and efficiency of primary care professionals to deliver PA counselling. To this end, appropriate training and financial support are crucial. Similarly, human resourcing and synergy between the different stakeholders must be addressed. To obtain maximum adherence, specific populations should be targeted and interventions adapted to their needs. Key enablers include motivational interviewing, social support and multi-disciplinary approaches. Leadership and lines of accountability must be clearly delineated to ensure the success of the initiatives promoting PA in primary care. The synergic and multisectoral action of several stakeholders, especially healthcare professionals, will help overcome physical inactivity in a sustainable way.

Correction to: Rotational profile alterations after anatomic posterolateral corner reconstructions in multiligament injured knees.

The original article can be found online.

Non-coding RNAs and exercise: pathophysiological role and clinical application in the cardiovascular system.

There is overwhelming evidence that regular exercise training is protective against cardiovascular disease (CVD), the main cause of death worldwide. Despite the benefits of exercise, the intricacies of their underlying molecular mechanisms remain largely unknown. Non-coding RNAs (ncRNAs) have been recognized as a major regulatory network governing gene expression in several physiological processes and appeared as pivotal modulators in a myriad of cardiovascular processes under physiological and pathological conditions. However, little is known about ncRNA expression and role in response to exercise. Revealing the molecular components and mechanisms of the link between exercise and health outcomes will catalyse discoveries of new biomarkers and therapeutic targets. Here we review the current understanding of the ncRNA role in exercise-induced adaptations focused on the cardiovascular system and address their potential role in clinical applications for CVD. Finally, considerations and perspectives for future studies will be proposed.

Side-to-side asymmetries in landing mechanics from a drop vertical jump test are not related to asymmetries in knee joint laxity following anterior cruciate ligament reconstruction.

PURPOSE: Asymmetries in knee joint biomechanics and increased knee joint laxity in patients following anterior cruciate ligament reconstruction (ACLR) are considered risk factors for re-tear or early onset of osteoarthritis. Nevertheless, the relationship between these factors has not been established. The aim of the study was to compare knee mechanics during landing from a bilateral drop vertical jump in patients following ACLR and control participants and to study the relationship between side-to-side asymmetries in landing mechanics and knee joint laxity. METHODS: Seventeen patients following ACLR were evaluated and compared to 28 healthy controls. Knee sagittal and frontal plane kinematics and kinetics were evaluated using three-dimensional motion capture (200 Hz) and two synchronized force platforms (1000 Hz). Static anterior and internal rotation knee laxities were measured for both groups and legs using dedicated arthrometers. Group and leg differences were investigated using a mixed model analysis of variance. The relationship between side-to-side differences in sagittal knee power/energy absorption and knee joint laxities was evaluated using univariate linear regression. RESULTS: A significant group-by-leg interaction (p = 0.010) was found for knee sagittal plane energy absorption, with patients having 25% lower values in their involved compared to their non-involved leg (1.22 ± 0.39 vs. 1.62 ± 0.40 J kg-1). Furthermore, knee sagittal plane energy absorption was 18% lower at their involved leg compared to controls (p = 0.018). Concomitantly, patients demonstrated a 27% higher anterior laxity of the involved knee compared to the non-involved knee, with an average side-to-side difference of 1.2 mm (p < 0.001). Laxity of the involved knee was also 30% higher than that of controls (p < 0.001) (leg-by-group interaction: p = 0.002). No relationship was found between sagittal plane energy absorption and knee laxity. CONCLUSIONS: Nine months following surgery, ACLR patients were shown to employ a knee unloading strategy of their involved leg during bilateral landing. However, this strategy was unrelated to their increased anterior knee laxity. Side-to-side asymmetries during simple bilateral landing tasks may put ACLR patients at increased risk of second ACL injury or early-onset osteoarthritis development. Detecting and correcting asymmetric landing strategies is highly relevant in the framework of personalized rehabilitation, which calls for complex biomechanical analyses to be applied in clinical routine. LEVEL OF EVIDENCE: III.

Ramp lesions associated with ACL injuries are more likely to be present in contact injuries and complete ACL tears.

PURPOSE: The purpose of this study was to analyse patient and injury characteristics as well as arthroscopic findings in a prospective cohort of ACL-injured patients with or without an associated ramp lesion. METHODS: Two hundred and twenty-four patients undergoing a primary (n = 196) or revision (n = 28) ACL reconstruction were included. The presence of a ramp lesion was determined by a systematic arthroscopic inspection of the posteromedial compartment. Chi-square tests were used to compare the population of ACL-injured patients with and without a ramp lesion regarding sex, age, body mass index, previous ACL injuries, sport before injury, and injury characteristics. Significance was set at p < 0.05. RESULTS: Fifty-three out of 224 patients had a ramp lesion (24%). The presence of the latter was not related to any of the analysed patient characteristics. The prevalence of the lesion was higher in contact injuries (n = 19; 41%) compared with non-contact injures (n = 34; 19%; p < 0.001). It was higher in patients with complete ACL ruptures (n = 49; 27%) as opposed to partial ruptures (n = 1; 4%; p = 0.01). A patient was 2.98 [95% CI 1.49-5.98] times more likely to have a ramp lesion if the ACL injury was declared to have been caused by direct contact and 8.71 [95% CI 1.15-66.12] times more likely if the ACL tear was complete. CONCLUSION: Ramp lesions may be anticipated in almost one out of four patients undergoing ACL reconstruction, especially if a patient sustained a contact injury and in the presence of a complete ACL tear. LEVEL OF EVIDENCE: III.

Injury risk in runners using standard or motion control shoes: a randomised controlled trial with participant and assessor blinding.

BACKGROUND/AIM: This randomised controlled trial investigated if the usage of running shoes with a motion control system modifies injury risk in regular leisure-time runners compared to standard shoes, and if this influence depends on foot morphology. METHODS: Recreational runners (n=372) were given either the motion control or the standard version of a regular running shoe model and were followed up for 6 months regarding running activity and injury. Foot morphology was analysed using the Foot Posture Index method. Cox regression analyses were used to compare injury risk between the two groups, based on HRs and their 95% CIs, controlling for potential confounders. Stratified analyses were conducted to evaluate the effect of motion control system in runners with supinated, neutral and pronated feet. RESULTS: The overall injury risk was lower among the participants who had received motion control shoes (HR=0.55; 95% CI 0.36 to 0.85) compared to those receiving standard shoes. This positive effect was only observed in the stratum of runners with pronated feet (n=94; HR=0.34; 95% CI 0.13 to 0.84); there was no difference in runners with neutral (n=218; HR=0.78; 95% CI 0.44 to 1.37) or supinated feet (n=60; HR=0.59; 95% CI 0.20 to 1.73). Runners with pronated feet using standard shoes had a higher injury risk compared to those with neutral feet (HR=1.80; 95% CI 1.01 to 3.22). CONCLUSIONS: The overall injury risk was lower in participants who had received motion control shoes. Based on secondary analysis, those with pronated feet may benefit most from this shoe type.

A new quantitative measure for radiologic osteoarthritis of the lateral knee compartment distinguishes patients with longstanding lateral meniscectomy from non-pathological knees.

PURPOSE: Common radiologic scores to evaluate knee osteoarthritis (OA) have been widely used but are descriptive and may lack objectivity. The aim of this study was to develop a quantitative and objective radiologic measure for the evaluation of lateral knee compartment OA. Furthermore, we tested the reliability of this new measure and its correlation to well-accepted radiologic scores. METHODS: This retrospective study was performed within the context of a multi-centre long-term follow-up (15-25 years) of a patient cohort after partial or total lateral meniscectomy (n = 36 knees). In addition, 99 radiographs of clinically and radiologically normal knees were obtained from a control group. Anteroposterior weight-bearing views (0°) and Schuss (45°) views were analysed. The joint height of the lateral knee compartment was measured on the lateral border (lateral joint space height) and in the centre (central joint space height, CJSH) and normalized with respect to the width of the lateral compartment (X). All measurements were taken independently by two observers, allowing for inter- and intra-observer reliability assessments. The results of the two groups were compared using an analysis of covariance. Finally, the correlations between the results and the Fairbank and Kellgren & Lawrence scores were determined using a Spearman ρ rank order correlation. RESULTS: The normalized joint space height in the centre of the compartment on the Schuss view (CJSH/X) showed the highest intra- (ICC = 0.980) and inter-observer reliability (ICC = 0.982). There was a significant difference in CJSH/X between the control (0.19 ± 0.05) and the meniscectomized knees (0.08 ± 0.07) (p < 0.001). CJSH/X showed a significant decline of 11 % per 10 years in the meniscectomy group. A negative correlation could be found between CJSH/X and the Fairbank (ρ = -0.751; p < 0.001) and Kellgren & Lawrence scores (ρ = -0.712; p < 0.001). A cut-off value of 0.14 of CJSH/X was defined-representing one standard deviation below the mean of the control group-from which measurements were considered as pathologic. CONCLUSION: The normalized joint space height measured in the centre of the lateral knee compartment from a Schuss view, CJSH/X, was highly reproducible and showed a significant correlation to established radiologic scores. This new measure has the advantage of being objective and dimensionless and thus independent of the size of the radiograph. The normative values provided by our healthy control knees are useful to help establish an early diagnosis of radiologic lateral knee compartment OA. LEVEL OF EVIDENCE: Retrospective diagnostic study, Level III.

Tracer kinetic modeling in myocardial perfusion quantification using MRI.

PURPOSE: To investigate and compare several quantification methods of myocardial perfusion measurements, paying special attention to the relation between the techniques and the required measurement duration. METHODS: Seven patients underwent contrast-enhanced rest and stress cardiac perfusion measurements at 3T. Three slices were acquired in each patient and were divided into 16 segments, leading to 112 rest and stress data curves, which were analyzed using various tracer kinetic models as well as a model-free deconvolution. Plasma flow, plasma volume, and myocardial perfusion reserve were analyzed for the complete acquisition as well as for the first pass data only. RESULTS: Deconvolution analysis yielded stable results for both rest and stress analysis, while Fermi and one compartment models agree well for first pass data (rest measurements only) and prolonged data acquisition (stress measurements only). More complex models do not yield satisfactory results for the short measurement times investigated in this study. CONCLUSIONS: When performing MRI-based quantification of myocardial perfusion, care must be taken that the method used is appropriate for the time frame under investigation. When a numerical deconvolution is used instead of tracer kinetic models, more stable results are obtained.

Towards new response criteria in neuroendocrine tumors: which changes in MRI parameters are associated with longer progression-free survival after radioembolization of liver metastases?

PURPOSE: To evaluate the association of therapy-related changes in imaging parameters with progression-free survival (PFS) of patients with unresectable liver metastases from neuroendocrine tumors (NETLMs). MATERIALS AND METHODS: Forty-five radioembolized patients (median age: 62 years; range: 43-75) received a pre- and 3 months posttherapeutic magnetic resonance imaging (MRI) examination. The latter were evaluated for tumor size, arterial enhancement, and necrosis pattern. Influences of therapy-related changes on PFS were analyzed. Statistical analysis included Student's t-test, Wilcoxon test, Cox regression analysis, and Kaplan-Meier curves. RESULTS: The median percentage decrease in sum of diameters was 9.7% (range: 43.9% decrease to 15.4% increase). Twenty-one patients (47%) showed increased necrosis. Three parameters were associated with significantly longer PFS: a decrease of diameter (hazard ratio [HR]: 0.206; 95% confidence interval [CI]: 0.058-0.725; P = 0.0139), a decrease in tumor arterial enhancement (HR: 0.143; 95% CI: 0.029-0.696; P = 0.0160), and an increase in necrosis after 3 months (HR: 0.321; 95% CI: 0.104-0.990; P = 0.0480). Multivariate analysis revealed that changes in diameter and arterial enhancement have complementary information and are associated independently with long PFS. CONCLUSION: A decrease both in sum of diameters and arterial enhancement of metastases, as well as an increase in necrosis, are associated with significantly longer PFS after radioembolization.

Understanding 3D TSE Sequences: Advantages, Disadvantages, and Application in MSK Imaging.

Three-dimensional (3D) turbo-spin echo (TSE) sequences have outgrown the stage of mere sequence optimization and by now are clinically applicable. Image blurring and acquisition times have been reduced, and contrast for T1-, T2-, and moderately T2-weighted (or intermediate-weighted) fat-suppressed variants has been optimized. Data on sound-to-noise ratio efficiency and contrast are available for moderately T2-weighted fat-saturated sequence protocols. The 3-T MRI scanners help to better exploit isotropic spatial resolution and multiplanar reformatting. Imaging times range from 5 to 10 minutes, and they are shorter than the cumulative acquisition times of three separate orthogonal two-dimensional (2D) sequences. Recent suggestions go beyond secondary reformations by using online 3D rendering for image evaluation. Comparative clinical studies indicate that the diagnostic performance of 3D TSE for imaging of internal derangements of joints is at least comparable with conventional 2D TSE with potential advantages of 3D TSE for small highly curved structures. But such studies, especially those with direct arthroscopic correlation, are still sparse. Whether 3D TSE will succeed in entering clinical routine imaging on a broader scale will depend on further published clinical evidence, on further reduction of imaging time, and on improvement of its integration into daily practice.

Combined anterior and rotational laxity measurements allow characterizing personal knee laxity profiles in healthy individuals.

PURPOSE: The aim of this study was to quantify sagittal and rotational knee laxity profiles taking into account individual influencing factors. METHODS: Linear regression models were used to determine which individual characteristics (age, height, body mass and sex) influenced the outcome in a group of 104 healthy subjects. The standardized residuals were used as individualized (corrected) laxity scores and were combined to determine knee laxity profiles. RESULTS: Anterior knee laxity was not influenced by individual characteristics. Rotational knee laxity was higher in females and inversely related to body mass. The correlation between anterior laxity and internal rotation scores was weak (r = 0.24, p = 0.02). The proportion of knees concerned by increased laxity scores (scores >1) was similar for anterior displacement, internal and external rotation (15 %). Only 32 % of the tested subjects showed a normal profile (score >-1 and <1) for all three directions, 33 % were concerned by hyperlaxity, 40 % by hypolaxity and 5 % by both. CONCLUSIONS: The diversity of laxity profiles found here highlights that the interpretation of multidirectional knee laxity is complex and suggests the necessity for individualized care of knee diseases and injuries. These results contribute to the understanding of knee laxity and throw the basis for prevention strategies and improvement of treatment outcomes in injuries and diseases. LEVEL OF EVIDENCE: Case series with no comparison groups, Level IV.

Hepatic steatosis: effect on hepatocyte enhancement with gadoxetate disodium-enhanced liver MR imaging.

PURPOSE: To investigate the effect of hepatic steatosis on enhancement of liver parenchyma with gadoxetate disodium-enhanced MR imaging. MATERIALS AND METHODS: Gadoxetate disodium-enhanced MR images of 166 patients were analyzed. Liver-spleen contrast and liver-spleen relative enhancement ratio on three-dimensional gradient echo T1-weighted images with fat suppression 20 minutes after injection of gadoxetate disodium were evaluated in correlation with fat signal fraction using the Pearson correlation coefficient and also compared between patients with normal liver parenchyma (n = 115) and with liver steatosis (n = 51) using the Student t-test. RESULTS: The liver-spleen contrast at hepatobiliary phase showed inverse correlations with the fat signal fraction (r = -0.36; P < 0.01), while the liver-spleen relative enhancement ratio showed no statistical correlation with the fat signal fraction (P = 0.80). The liver-spleen contrast in the group with steatotic liver was significantly lower than that in the group with normal livers (P < 0.001). There was no significant difference in the relative enhancement ratio between the two groups (P = 0.85). CONCLUSION: Our results may suggest that hepatic steatosis does not affect the uptake of gadoxetate disodium into hepatocytes and are considered crucial as background knowledge in extending the use of gadoxetate disodium-enhanced MR imaging to quantitate liver function.

Diffusion-weighted MRI of the prostate: advantages of Zoomed EPI with parallel-transmit-accelerated 2D-selective excitation imaging.

OBJECTIVES: The purpose of our study was to evaluate the use of 2D-selective, parallel-transmit excitation magnetic resonance imaging (MRI) for diffusion-weighted echo-planar imaging (pTX-EPI) of the prostate, and to compare it to conventional, single-shot EPI (c-EPI). METHODS: The MRI examinations of 35 patients were evaluated in this prospective study. PTX-EPI was performed with a TX-acceleration factor of 1.7 and a field of view (FOV) of 150 × 90 mm(2), whereas c-EPI used a full FOV of 380 × 297 mm(2). Two readers evaluated three different aspects of image quality on 5-point Likert scales. To quantify distortion artefacts, maximum diameters and prostate volume were determined for both techniques and compared to T2-weighted imaging. RESULTS: The zoomed pTX-EPI was superior to c-EPI with respect to overall image quality (3.39 ± 0.62 vs 2.45 ± 0.67) and anatomic differentiability (3.29 ± 0.65 vs 2.41 ± 0.65), each with p < 0.0001. Artefacts were significantly less severe in pTX-EPI (0.93 ± 0.73 vs 1.49 ± 1.08), p < 0.001. The quantitative analysis yielded a higher agreement of pTX-EPI with T2-weighted imaging than c-EPI with respect to coronal (ICCs: 0.95 vs 0.93) and sagittal (0.86 vs 0.73) diameters as well as prostate volume (0.94 vs 0.92). Apparent diffusion coefficient (ADC) values did not differ significantly between the two techniques (p > 0.05). CONCLUSIONS: Zoomed pTX-EPI leads to substantial improvements in diffusion-weighted imaging (DWI) of the prostate with respect to different aspects of image quality and severity of artefacts. KEY POINTS: Recent technical developments in MRI allow the use of accelerated, spatially-selective excitation (parallel-transmit, pTX). pTX can be used for zoomed echo-planar prostate imaging (pTX-EPI). pTX-EPI improves different aspects of image quality in prostate MRI. Distortion artefacts are reduced by the use of pTX-EPI in prostate MRI. Further studies should aim at assessing the diagnostic accuracy of pTX-EPI.

Influence of midsole hardness of standard cushioned shoes on running-related injury risk.

BACKGROUND: In this double-blind randomised controlled trial, we tested if leisure-time runners using shoes with less compliant midsoles have a higher running-related injury (RRI) risk. METHOD: We provided 247 runners with standard running shoes having either a soft study shoes (soft-SS) or a hard study shoes (hard-SS) midsole and followed them prospectively for 5 months regarding RRI. All information about sports practice and injuries was uploaded on a dedicated internet platform and checked for consistency and completeness. RRI was defined as any first-time pain sustained during or as a result of running practice and impeding normal running activity for at least 1 day. Cox proportional hazards regressions were used to identify RRI risk factors. RESULT: The type of study shoes used for running was not associated with RRIs (HR=0.92; 95% CI 0.57 to 1.48). The hard-SS had a 15% greater overall stiffness in the heel region. The two study groups were similar regarding personal and sports participation characteristics, except for years of running experience, which was higher (p<0.05) in the hard-SS group. Global RRI incidence was 12.1 RRI/1000 h of running. No between-group differences were found regarding injury location, type, severity or category. Nevertheless, the adjusted regression model revealed positive associations with RRI risk for body mass index (HR=1.126; 95% CI 1.033 to 1.227), previous injury (HR=1.735; 95% CI 1.037 to 2.902) and mean session intensity (HR=1.396; 95% CI 1.040 to 1.874). Protective factors were previous regular running activity (HR=0.422; 95% CI 0.228 to 0.779) and weekly volume of other sports activities (HR=0.702; 95% CI 0.561 to 0.879). CONCLUSIONS: Midsole hardness of modern cushioned running shoes does not seem to influence RRI risk.

Rotational profile alterations after anatomic posterolateral corner reconstructions in multiligament injured knees.

PURPOSE: Injuries of the posterolateral corner (PLC) are rare and severe knee injuries, resulting in posterolateral rotatory instability and an increase in external rotation. Surgical reconstruction techniques reproducing the normal anatomy showed promising results. In vivo evaluations of static rotational knee laxity at 30° of knee flexion have not been reported so far. The purpose of this study was to evaluate static rotational knee laxity after anatomic PLC reconstructions. METHODS: This is a retrospective clinical cohort study. Twenty patients with PLC reconstructions with an average follow-up time of 39 ± 22 months and no history of knee trauma or surgery of the contralateral knee were included in the study. They underwent a routine clinical examination and static rotational laxity measurements at 30° of knee flexion in the prone position. Side-to-side differences were recorded and compared to a group of matched controls. RESULTS: The postoperative IKDC score was graded A for 8 patients, B for 16, C for 6 and D for one patient. The primary goal of the surgical procedure which consists in reducing excessive external tibiofemoral rotation could be reached in 18 of the 20 patients (90%). Anatomic PLC reconstructions yielded a comparable rotational profile in operated and healthy knees in 7 patients (35%). Thirteen patients (65%) presented a significantly altered rotational profile in comparison with a healthy control group. Unexpected increases in internal rotation were found in 8 patients (40%). CONCLUSION: Anatomic PLC reconstructions reduced excessive external tibiofemoral rotation in a vast majority of patients. Static rotational laxity measurements allowed for a determination of the patients' individual rotational profile after PLC reconstructions. This profile was normalised in only one-third of the patients. The understanding of this finding needs further investigation as well as the clinical impact of rotational profile alterations on knee function. LEVEL OF EVIDENCE: Diagnostic studies, Level III.

Moderate to severe injuries in football: a one-year prospective study of twenty-four female and male amateur teams.

This study aimed to realize a prospective follow-up of the injuries occurring in female and male football players involved in the highest league in the Grand-Duchy of Luxembourg. Data concerning anthropometric characteristics and football activities were gathered in 125 female and 243 male football players via questionnaires at the beginning of the study. Then, a follow-up of moderate to severe injuries (> 15 days of interruption in football practice) was performed throughout the season 2013-2014. Sixteen injuries (injury incidence = 0.7 injuries/1000 h of exposure) were observed in 13 female football players (10.4%). These injuries concerned mainly the knee (n = 7; 43.7%), with capsules and ligaments being the most often concerned tissues (n = 7; 43.7%). In male football players, 41 severe injuries (injury incidence = 0.6 injuries/1000 h of exposure) were observed in 36 players (14.8%). These injuries concerned mainly the thighs (n = 12; 29.3%) and the muscles and tendons were the most often concerned tissues (n = 18; 43.9%). Injuries in football are predominantly located at the lower limbs, particularly the knees in female football players. The predominant muscle and tendon lesions of the thighs occurring in males could reveal that physical preparation is insufficient or inadequate for a number of players. Regarding these results, it is necessary to implement an injury prevention strategy. The "FIFA 11+" programme could be used as the basic method, but should be personalized according to sex. The injury collection methodology could be optimized with the use of an electronic database, such as the Training and Injury Prevention Platform for Sports (TIPPS). Beside the systematic recording of injury data (as well as the training load) by the players or the medical staff, this system allows to share of important information between stakeholders, follow-up the players, provide risk factor warnings and increase the awareness of the injury problem.

Gait asymmetry in spatiotemporal and kinetic variables does not increase running-related injury risk in lower limbs: a secondary analysis of a randomised trial including 800+ recreational runners.

Objective: To investigate asymmetry in spatiotemporal and kinetic variables in 800+ recreational runners, identify determinants of asymmetry, investigate if asymmetry is related to greater running injury risk and compare spatiotemporal and kinetic variables between the involved and uninvolved limb at baseline in runners having sustained an injury during follow-up. Methods: 836 healthy recreational runners (38.6% women) were tested on an instrumented treadmill at their preferred running speed at baseline and followed up for 6 months. From ground reaction force recordings, spatiotemporal and kinetic variables were derived for each lower limb. The Symmetry Index was computed for each variable. Correlations and multiple regression analyses were performed to identify potential determinants of asymmetry. Cox regression analyses investigated the association between asymmetry and injury risk. Analysis of variance for repeated measures was used to compare the involved and uninvolved limbs in runners who had sustained injuries during follow-up. Results: 107 participants reported at least one running-related injury. Leg length discrepancy and fat mass were the most common determinants of asymmetry, but all correlation coefficients were negligible (0.01-0.13) and explained variance was very low (multivariable-adjusted R2<0.01-0.03). Greater asymmetry for flight time and peak breaking force was associated with lower injury risk (HR (95% CI): 0.80 (0.64 to 0.99) and 0.96 (0.93 to 0.98), respectively). No between-limb differences were observed in runners having sustained an injury. Conclusion: Gait asymmetry was not associated with higher injury risk for investigated spatiotemporal and kinetic variables. Trial registration number: NCT03115437.