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Problem/Intro: Epidemiological data of injuries and illnesses in equestrian athletes are limited. The objective of this study was to describe the incidence, prevalence, and severity of health problems among a cohort of elite riders.Methods: We conducted a prospective cohort study with 38 elite equestrian athletes over a two-year follow-up period. Health problems were recorded weekly with the Oslo Sports Trauma Research Center Questionnaire on health problems and subsequently categorized into illnesses and injuries according to the recently published International Olympic Committee guidelines. Based on the athletes weekly responses, we calculated health problem prevalence, incidence and severity.Results: A total of 93 health problems were reported including 30 illnesses and 63 injuries resulting in a weekly prevalence of 12.1% (95% CI: 10.5-13.7) for all health problems. For acute injuries, the chest, lumbosacral region, and neck were the most commonly reported body locations. The lumbosacral region was the most commonly reported repetitive injury mechanism body region. Illnesses most often affected the upper respiratory and gastrointestinal body systems.Conclusion: There was a low prevalence of injuries among this cohort of elite athletes. Future efforts that further improve athlete safety should focus on repetitive mechanism injuries and implementation and scale-up of preventive equipment to the broader equestrian population.Key Words: Epidemiology, Acute Injury, Repetitive Injury, Injury Mechanism

Problem: Epidemiological data of injuries and illnesses in water polo athletes are limited. This studys objective was to describe the incidence, prevalence, and severity of health problems among a cohort of elite Players.Methods: We conducted a prospective cohort study with 24 elite waterpolo athletes over 2.5 years. Health problems were recorded weekly with the Oslo Sports Trauma Research Center Questionnaire on health problems and subsequently categorized into illnesses and injuries according to the recently published International Olympic Committee guidelines. Based on the athletes weekly responses, we calculated health problem prevalence, incidence and severity.Results: A total of 288 health problems were reported, including 76 illnesses and 212 injuries resulting in a weekly prevalence of 30.3% (95% CI: 28.2-32.4) for all health problems. Of these, 115 (39.9%) were categorized as substantial, of which 76 were illnesses, and 39 were injuries. The overall acute injury incidence rate was 1.66 injuries (95% CI: 1.23-2.09) per 1,000 sports exposure hours. The training and competition acute injury incidence rates were, respectively, 1.20 (95%CI: 0.81 1.59) per 1,000 training hours and 5.38 (95% CI: 3.18 7.58) per 1,000 competition hours.Conclusion: There was a high prevalence of injuries among this cohort of elite water polo athletes. Future efforts that further improve athlete safety should focus on both acute and repetitive mechanism injuries.Key Words: Epidemiology, Acute Injury, Repetitive Injury, Injury Mechanism

Background: Arthroscopic surgery of the hip is being increasingly used to diagnose and treat various abnormalities, including acetabular labral tears. Magnetic resonance arthrography has been suggested as the imaging test of choice for the evaluation of the acetabular labrum. There is substantial variability in the previously reported accuracy of magnetic resonance arthrography for diagnosing labral lesions. Interobserver reliability has not been established previously. The purpose of this study was to establish the interobserver reliability and the validity of magnetic resonance arthrography for detecting lesions of the acetabular labrum in a retrospective case series.Methods: Two radiologists independently assessed the acetabular labrum on magnetic resonance arthrograms of ninety-five hips in ninety-three patients who underwent hip arthroscopy for a suspected acetabular labral lesion. Magnetic resonance arthrography findings were compared with the gold standard, which was defined as the assessment of the labrum during the hip arthroscopy.Results: At arthroscopy, ninety-one labral lesions were identified in the ninety-five hips. The interobserver reliability of detecting labral lesions with magnetic resonance arthrography was fair (kappa=0.268). Magnetic resonance arthrography, as interpreted by observers A and B, showed a sensitivity of 86% and 86%, specificity of 75% and 50%, negative predictive value of 19% and 13%, and positive predictive value of 99% and 98%, respectively.Conclusions: Because of its limited reliability and the high prevalence of labral lesions, magnetic resonance arthrography provides a limited complementary benefit in the detection of labral lesions in patients with a high clinical suspicion of labral pathology. When there is a high clinical suspicion of a labral lesion, magnetic resonance arthrography has a poor negative predictive value and cannot be used to rule out a labral lesion. Physicians should critically consider whether the findings on a magnetic resonance arthrogram will alter the treatment strategy for an individual patient with a clinical suspicion of labral pathology. [ABSTRACT FROM AUTHOR]

Objective The purpose of this study was to describe the results of two treatment regimens for medial tibial stress syndrome (MTSS); a graded running programme and the same running programme with additional shockwave therapy (extracorporeal shockwave therapy; ESWT). Design A prospective observational controlled trial. Setting Two different sports medicine departments. Participants 42 athletes with MTSS were included. Intervention Patients from one hospital were treated with a graded running programme, while patients from the other hospital were treated with the same graded running programme and focused ESWT (five sessions in 9 weeks). Main Outcome Measures Time to full recovery (the endpoint was being able to run 18 min consecutively without pain at a fixed intensity). Results The time to full recovery was significantly faster in the ESWT group compared with the patients who only performed a graded running programme, respectively 59.7±25.8 and 91.6±43.0 days (p=0.008). Conclusions This prospective observational study showed that MTSS patients may benefit from ESWT in addition to a graded running programme. ESWT as an additional treatment warrants further investigation in a prospective controlled trial with the addition of randomisation and double blinding. [ABSTRACT FROM AUTHOR]

Background Despite the high rate of hamstring injuries, there is no consensus on their management, with a large number of different interventions being used. Recently several new injection therapies have been introduced. Objective To systematically review the literature on the effectiveness of therapeutic interventions for acute hamstring injuries. Data sources The databases of PubMed, EMBASE, Web of Science, Cochrane Library, CINAHL and SPORTDiscus were searched in May 2011. Study eligibility criteria Prospective studies comparing the effect of an intervention with another intervention or a control group without intervention in subjects with acute hamstring injuries were included. Data analysis Two authors independently screened the search results and assessed risk of bias. Quality assessment of the included studies was performed using the Physiotherapy Evidence Database score. A best evidence synthesis was used to identify the level of evidence. Main results Six studies were included in this systematic review. There is limited evidence for a positive effect of stretching, agility and trunk stability exercises, intramuscular actovegin injections or slump stretching in the management of acute hamstring injuries. Limited evidence was found that there is no effect of non-steroidal anti-inflammatory drugs or manipulation of the sacroiliac joint. Conclusions There is a lack of high quality studies on the treatment of acute hamstring injuries. Only limited evidence was found to support the use of stretching, agility and trunk stability exercises, intramuscular actovegin injections or slump stretching. Further research is needed using an appropriate control group, randomisation and blinding. [ABSTRACT FROM AUTHOR]

Medial tibial stress syndrome (MTSS) is one of the most common leg injuries in athletes and soldiers. The incidence of MTSS is reported as being between 4% and 35% in military personnel and athletes. The name given to this condition refers to pain on the posteromedial tibial border during exercise, with pain on palpation of the tibia over a length of at least 5 cm. Histological studies fail to provide evidence that MTSS is caused by periostitis as a result of traction. It is caused by bony resorption that outpaces bone formation of the tibial cortex. Evidence for this overloaded adaptation of the cortex is found in several studies describing MTSS findings on bone scan, magnetic resonance imaging (MRI), high-resolution computed tomography (CT) scan and dual energy x-ray absorptiometry. The diagnosis is made based on physical examination, although only one study has been conducted on this subject. Additional imaging such as bone, CT and MRI scans has been well studied but is of limited value. The prevalence of abnormal findings in asymptomatic subjects means that results should be interpreted with caution. Excessive pronation of the foot while standing and female sex were found to be intrinsic risk factors in multiple prospective studies. Other intrinsic risk factors found in single prospective studies are higher body mass index, greater internal and external ranges of hip motion, and calf girth. Previous history of MTSS was shown to be an extrinsic risk factor. The treatment of MTSS has been examined in three randomized controlled studies. In these studies rest is equal to any intervention. The use of neoprene or semi-rigid orthotics may help prevent MTSS, as evidenced by two large prospective studies. [ABSTRACT FROM AUTHOR]

Objective: To establish the prevalence of mental health symptoms (MHSs ) among Dutch elite athletes and their coaches, to examine the association between potential contributing factors and MHS among Dutch elite athletes and their coaches and to explore the view and needs of Dutch elite athletes and their coaches regarding mental health resources and support., Methods: A cross-sectional study was conducted by distributing an electronic questionnaire based on validated screening questionnaires for the assessment of MHS., Results: In total, 156 athletes (55 % female) and 95 coaches (79 % male) across various sports participated in this study. The most prevalent MHS among athletes and coaches were distress (73 % and 41 %) and alcohol misuse (52 % and 53 %). Adverse life events showed an association with anxiety, depression, sleep disturbance, alcohol misuse and disordered eating while severe injuries showed an association with distress and sleep disturbance in elite athletes. Among coaches, no significant associations were found between potential contributing factors and MHS. 60 % of the athletes and 60 % of the coaches (totally) agreed that they could openly address their mental health issues within their sport while 53 % of the athletes and 41 % of the coaches (totally) agreed a need for increased attention regarding mental health/guidance in their sport., Conclusions: MHSs are prevalent among Dutch elite athletes and coaches. Recent adverse life events and severe injuries have a potential intersection with MHS in elite athletes. There is a need for increased attention regarding mental health/guidance among Dutch elite athletes and coaches within their sport so that subsequent treatment/support can be provided., Competing Interests: None declared., (Copyright © Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Studies identifying clinical and MRI reinjury risk factors are limited by relatively small sample sizes. This study aimed to examine the association between baseline clinical and MRI findings with the incidence of hamstring reinjuries using a large multicentre dataset., Methods: We merged data from four prospective studies (three randomised controlled trials and one ongoing prospective case series) from Qatar and the Netherlands. Inclusion criteria included patients with MRI-confirmed acute hamstring injuries (<7 days). We performed multivariable modified Poisson regression analysis to assess the association of baseline clinical and MRI data with hamstring reinjury incidence within 2 months and 12 months of follow-up., Results: 330 and 308 patients were included in 2 months (31 (9%) reinjuries) and 12 months (52 (17%) reinjuries) analyses, respectively. In the 2-month analysis, the presence of discomfort during the active knee extension test was associated with reinjury risk (adjusted risk ratio (ARR) 3.38; 95% CI 1.19 to 9.64). In the 12 months analysis, the time to return to play (RTP) (ARR 0.99; 95% CI 0.97 to 1.00), straight leg raise angle on the injured leg (ARR 0.98; 95% CI 0.96 to 1.00), the presence of discomfort during active knee extension test (ARR 2.52; 95% CI 1.10 to 5.78), the extent of oedema anteroposterior on MRI (ARR 0.74; 95% CI 0.57 to 0.96) and myotendinous junction (MTJ) involvement on MRI (ARR 3.10; 95% CI 1.39 to 6.93) were independently associated with hamstring reinjury., Conclusions: Two clinical findings (the presence of discomfort during active knee extension test, lower straight leg raise angle on the injured leg), two MRI findings (less anteroposterior oedema, MTJ involvement) and shorter time to RTP were independently associated with increased hamstring reinjury risk. These findings may assist the clinician to identify patients at increased reinjury risk following acute hamstring injury., Trial Registration Numbers: NCT01812564; NCT02104258; NL2643; NL55671.018.16., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Objective: Longitudinal consequences and potential interactions of COVID-19 and elite-level sports and exercise are unclear. Therefore, we determined the long-term detrimental cardiac effects of the interaction between SARS-CoV-2 infection and the highest level of sports and exercise., Methods: This prospective controlled study included elite athletes from the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise cohort. Athletes infected with SARS-CoV-2were offered structured, additional cardiovascular screenings, including cardiovascular MRI (CMR). We compared ventricular volumes and function, late gadolinium enhancement (LGE) and T1 relaxation times, between infected and non-infected elite athletes, and collected follow-up data on cardiac adverse events, ventricular arrhythmia burden and the cessation of sports careers., Results: We included 259 elite athletes (mean age 26±5 years; 40% women), of whom 123 were infected (9% cardiovascular symptoms) and 136 were controls. We found no differences in function and volumetric CMR parameters. Four infected athletes (3%) demonstrated LGE (one reversible), compared with none of the controls. During the 26.7 (±5.8) months follow-up, all four athletes resumed elite-level sports, without an increase in ventricular arrhythmias or adverse cardiac remodelling. None of the infected athletes reported new cardiac symptoms or events. The majority (n=118; 96%) still participated in elite-level sports; no sports careers were terminated due to SARS-CoV-2., Conclusions: This prospective study demonstrates the safety of resuming elite-level sports after SARS-CoV-2 infection. The medium-term risks associated with SARS-CoV-2 infection and elite-level sports appear low, as the resumption of elite sports did not lead to detrimental cardiac effects or increases in clinical events, even in the four elite athletes with SARS-CoV-2 associated myocardial involvement., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Ankle osteoarthritis is debilitating and usually affects relatively young people, often as a result of previous ankle traumas, frequently occurring in sports. Platelet-rich plasma (PRP) injections for ankle osteoarthritis have shown no evidence of benefit over the course of 26 weeks. Previous studies on PRP for knee osteoarthritis showed that clinically significant improvements with PRP occurred between 6 to 12 months in the absence of initial benefit. No studies have evaluated the effect of PRP from 6 to 12 months in ankle osteoarthritis., Purpose: To assess the efficacy of PRP injections in ankle osteoarthritis over the course of 52 weeks., Study Design: Randomized controlled trial; Level of evidence, 1., Methods: In this 52-week follow-up trial, 100 patients with ankle osteoarthritis were randomized to a PRP group or placebo (saline) group. Patients received 2 intra-articular talocrural injections: at inclusion and after 6 weeks. Patient-reported outcome measures were used to assess pain, function, quality of life, and indirect costs over 52 weeks., Results: Two patients (2%) were lost to follow-up. The adjusted between-group difference for the patient-reported American Orthopaedic Foot & Ankle Society score over 52 weeks was -2 points (95% CI, -5 to 2; P = .31) in favor of the placebo group. No significant between-group differences were observed for any of the secondary outcome measures., Conclusion: For patients with ankle osteoarthritis, PRP injections did not improve ankle symptoms and function over 52 weeks compared with placebo injections., Registration: NTR7261 (Netherlands Trial Register).

Introduction: The cardiovascular benefits of physical exercise are well-known. However, vigorous exercise has also been associated with adverse cardiac effects. To improve our understanding of cardiovascular adaptation to exercise versus maladaptation and pathology, the limits of adaptation should be firmly established using state-of-the-art diagnostic modalities. We therefore initiated the Evaluation of Lifetime participation in Intensive Top-level sports and Exercise (ELITE) cohort to investigate the longitudinal (beneficial and pathological) cardiovascular effects of intensive elite sports and exercise., Methods and Analysis: ELITE is a prospective, multicentre, longitudinal cohort study. Elite athletes, from the age of sixteen, are recruited in The Netherlands. The primary objective is to determine the association between elite sports and exercise-induced cardiac remodelling, cardiac pathology, and health benefits over time. Secondary objectives include determining and identifying genetic profiles of elite athletes, and how these are associated with cardiac indices. ELITE will collect data from consultations, electrocardiography, echocardiography and cardiac magnetic resonance imaging, and training- and injury data. ELITE will also collect blood for biobanking and cardiogenetics. Follow-up will take place at intervals of two to five years, and after the elite athletes' professional careers have ended. In addition, a subcohort of ELITE has been established to investigate cardiac sequelae following infections associated with myocardial involvement, including SARS-CoV-2. ELITE is a prospective observational study; therefore, analyses will be primarily explorative., Ethics and Dissemination: This study has been approved by the Medical Ethics Review Board of the Amsterdam University Medical Centers (NL71682.018.19). The results of the study will be disseminated by publication in peer-reviewed journals (Netherlands Trial Register number: NL9328)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Our aim was to assess the effects of adding arch-support foot-orthoses (ASFO) to a multimodal therapeutic intervention on the perception of pain and improvement of recovery from medial tibial stress syndrome (MTSS) in recreational runners., Design: A prospective randomized controlled trial., Setting: Sport training and medical centers., Participants: Fifty female recreational runners with MTSS were randomized into 2 groups., Interventions: Runners either received ASFO or sham flat noncontoured orthoses. Both groups received a multimodal therapeutic intervention, including ice massage, ankle muscle exercises, and extracorporeal shockwave therapy., Main Outcome Measures: Pain during bone pressure using a numerical Likert scale (0-10), MTSS severity using an MTSS scale, perceived treatment effect using the global rating of change scale, and quality of life using the short Form-36 questionnaire were determined at week 6, 12, and 18., Results: Pain intensity and MTSS severity were lower, and the perceived treatment effect and physical function were better in the ASFO than in the sham flat noncontoured orthoses group at week 6 and week 12. Cohen's dz effect size for between-group differences showed a medium difference. However, arch-support foot-orthoses did not add to the benefits of multimodal therapeutic intervention on pain, MTSS severity and perceived treatment effect at week 18., Conclusions: Adding ASFO to a therapeutic intervention leads to an earlier diminishment of pain and MTSS severity, and improved PF and perceived therapeutic effects., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: To prospectively evaluate 1-year clinical and radiological outcomes after operative and non-operative treatment of proximal hamstring tendon avulsions., Methods: Patients with an MRI-confirmed proximal hamstring tendon avulsion were included. Operative or non-operative treatment was selected by a shared decision-making process. The primary outcome was the Perth Hamstring Assessment Tool (PHAT) score. Secondary outcome scores were Proximal Hamstring Injury Questionnaire, EQ-5D-3L, Tegner Activity Scale, return to sports, hamstring flexibility, isometric hamstring strength and MRI findings including proximal continuity., Results: Twenty-six operative and 33 non-operative patients with a median age of 51 (IQR: 37-57) and 49 (IQR: 45-56) years were included. Median time between injury and initial visit was 12 (IQR 6-19) days for operative and 21 (IQR 12-48) days for non-operative patients (p=0.004). Baseline PHAT scores were significantly lower in the operative group (32±16 vs 45±17, p=0.003). There was no difference in mean PHAT score between groups at 1 year follow-up (80±19 vs 80±17, p=0.97). Mean PHAT score improved by 47 (95% CI 39 to 55, p<0.001) after operative and 34 (95% CI 27 to 41, p<0.001) after non-operative treatment. There were no relevant differences in secondary clinical outcome measures. Proximal continuity on MRI was present in 20 (95%, 1 recurrence) operative and 14 (52%, no recurrences) non-operative patients (p=0.008)., Conclusion: In a shared decision-making model of care, both operative and non-operative treatment of proximal hamstring tendon avulsions resulted in comparable clinical outcome at 1-year follow-up. Operative patients had lower pretreatment PHAT scores but improved substantially to reach comparable PHAT scores as non-operative patients. We recommend using this shared decision model of care until evidence-based indications in favour of either treatment option are available from high-level clinical trials., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Ureteric injury is a rare but serious, iatrogenic complication of hysterectomy. The risk depends on indication for surgery, predisposing risk factors, and peroperative conditions. Our aims were to evaluate and learn from compensation claims to The Norwegian System of Patient Injury Compensation (NPE) for ureteric injury occurring during hysterectomies to predict risk factors, time of identification, symptoms, and consequences, and to relate these cases to injuries registered in The Norwegian Patient Registry., Material and Methods: A retrospective study of ureteric injuries occurring during hysterectomies, reported to NPE and the Norwegian Patient Registry from 2009 through 2019., Results: During the study period, 53 096 hysterectomies were registered in The Norwegian Patient Registry, of which ureteric injury was documented in 643 (1.2%). More ureteric injuries were registered in large hospital trusts than in small trusts (1.3% vs. 0.7%, p < 0.05). NPE received 69 claims due to ureteric injury occurring during hysterectomy, comprising 11% of all injuries in the study period. Compensation was approved for 15%. Women who claimed compensation were younger (48.1 ± 8.9 years vs. 55.1 ± 13.6 years, p < 0.01), more likely to have had a benign diagnosis (89.9% vs. 52.1%, p < 0.01), and more likely to have had the ureteric injury recognized after discharge (58.0% vs. 33.0%, p < 0.001) compared with non-complainants. Identification of the ureters during the hysterectomy was documented in 30% of the NPE patient files. Additional information for the NPE cases included the following. The most common symptoms of unidentified injury were pain (77%), fever (12%), urinary leakage (13%), and anuria (8%). Re-operation was necessary in 77% of the cases, and 10% of the women lost one kidney. Long-term consequences after repair, such as loss of a kidney or persistent pain, were seen in 17%. No women died because of the injury., Conclusions: The incidence of ureteric injury occurring during hysterectomy in Norway was 1.2%; 11% involved a claim for compensation, and 15% of these had their case approved. Most ureteric injuries were not recognized during the hysterectomy. Documentation of peroperative identification of the ureters during hysterectomy was often missing. Vigilance to pain as a postoperative symptom of peroperative unrecognized ureteric injury may result in earlier diagnosis and treatment., (© 2021 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

Importance: Approximately 3.4% of adults have ankle (tibiotalar) osteoarthritis and, among younger patients, ankle osteoarthritis is more common than knee and hip osteoarthritis. Few effective nonsurgical interventions exist, but platelet-rich plasma (PRP) injections are widely used, with some evidence of efficacy in knee osteoarthritis., Objective: To determine the effect of PRP injections on symptoms and function in patients with ankle osteoarthritis., Design, Setting, and Participants: A multicenter, block-randomized, double-blinded, placebo-controlled clinical trial performed at 6 sites in the Netherlands that included 100 patients with pain greater than 40 on a visual analog scale (range, 0-100) and tibiotalar joint space narrowing. Enrollment began on August 24, 2018, and follow-up was completed on December 3, 2020., Interventions: Patients were randomly assigned (1:1) to receive 2 ultrasonography-guided intra-articular injections of either PRP (n = 48) or placebo (saline; n = 52)., Main Outcomes and Measures: The primary outcome was the validated American Orthopaedic Foot and Ankle Society score (range, 0-100; higher scores indicate less pain and better function; minimal clinically important difference, 12 points) over 26 weeks., Results: Among 100 randomized patients (mean age, 56 years; 45 [45%] women), no patients were lost to follow-up for the primary outcome. Compared with baseline values, the mean American Orthopaedic Foot and Ankle Society score improved by 10 points in the PRP group (from 63 to 73 points [95% CI, 6-14]; P < .001) and 11 points in the placebo group (from 64 to 75 points [95% CI, 7-15]; P < .001). The adjusted between-group difference over 26 weeks was -1 ([95% CI, -6 to 3]; P = .56). One serious adverse event was reported in the placebo group, which was unrelated to the intervention; there were 13 other adverse events in the PRP group and 8 in the placebo group., Conclusions and Relevance: Among patients with ankle osteoarthritis, intra-articular PRP injections, compared with placebo injections, did not significantly improve ankle symptoms and function over 26 weeks. The results of this study do not support the use of PRP injections for ankle osteoarthritis., Trial Registration: Netherlands Trial Register: NTR7261.

Objective: Stem cell therapy is increasingly used for knee osteoarthritis (KOA). We aimed to review the evidence of autologous mesenchymal stem cell therapy on pain, function and severity on imaging in KOA., Design: Systematic review of randomised controlled trials (RCTs)., Eligibility Criteria: RCTs evaluating autologous mesenchymal stem cell (MSC) therapy on patient-reported outcome measures and disease severity., Data Sources: Seven databases were searched until 31 December 2020., Risk of Bias and Data Synthesis: Risk of bias was assessed using the ROB V.2. We used Grading of Recommendations Assessment, Development and Evaluation to appraise the certainty of the evidence. Data were synthesised descriptively., Results: Fourteen RCTs were included. A total of 408 patients with KOA received MSC therapy derived from bone marrow, adipose tissue or activated peripheral blood. After 1 year, 19 of 26 (73%) clinical outcome measures improved with MSCs compared with control. In the MSC group, patients improved by 1.8-4.4 points on the Visual Analogue Scale (0-10) and 18-32 points of the Knee Osteoarthritis Outcome Score (0-100). Four studies showed better disease severity on imaging after MSC compared with control at 1 year. Ten of 14 (71%) RCTs were at high risk of bias on all outcomes. No serious adverse events were reported after MSC therapy during a maximum of 4 years follow-up., Conclusion: We found a positive effect of autologous MSC therapy compared with control treatments on patient-reported outcome measures, and disease severity. The certainty of this evidence was low to very low., Prospero Registration Number: CRD42019120506., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Previous studies have shown low to moderate evidence for a variety of magnetic resonance imaging (MRI) features as prognostic factors in athletes with hamstring injuries. Short-tau inversion recovery (STIR) signal intensity has not yet been investigated for assessing the prognosis of acute muscle injuries. Our aim was to explore the relationship between MRI STIR signal intensity and time to return to play (RTP) and to investigate the association between MRI STIR and reinjury risk in athletes with acute hamstring injuries., Study Design: Case-control study., Methods: We used MRI STIR to measure intramuscular signal intensity in patients with clinically diagnosed hamstring injuries at two time points: at injury and RTP. At injury, we calculated the association of MRI STIR signal intensity with the time to RTP and reinjury risk. At RTP, the association of MRI STIR signal intensity and reinjury risk and the change in MRI STIR signal intensity over time on reinjury risk was evaluated., Results: 51 patients were included. We found increased MRI STIR signal intensity: (1) at time of injury not to be associated with time to RTP, (2) at time of injury to be associated with a slightly lower risk for reinjury: odds 0.986 (0.975-0.998, p=0.02) and (3) at RTP not to be associated with reinjury risk. (4) We found no association between the change in MRI STIR signal intensity over time and reinjury risk., Conclusion: Increased MRI STIR signal intensity at injury has no value in time to RTP prognosis, but is associated with a reduced reinjury risk., (Copyright © 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The environmental conditions during the Tokyo Olympic and Paralympic Games are expected to be challenging, which increases the risk for participating athletes to develop heat-related illnesses and experience performance loss. To allow safe and optimal exercise performance of Dutch elite athletes, the Thermo Tokyo study aimed to determine thermoregulatory responses and performance loss among elite athletes during exercise in the heat, and to identify personal, sports-related, and environmental factors that contribute to the magnitude of these outcomes. For this purpose, Dutch Olympic and Paralympic athletes performed two personalized incremental exercise tests in simulated control (15°C, relative humidity (RH) 50%) and Tokyo (32°C, RH 75%) conditions, during which exercise performance and (thermo)physiological parameters were obtained. Thereafter, athletes were invited for an additional visit to conduct anthropometric, dual-energy X-ray absorptiometry (DXA), and 3D scan measurements. Collected data also served as input for a thermophysiological computer simulation model to estimate the impact of a wider range of environmental conditions on thermoregulatory responses. Findings of this study can be used to inform elite athletes and their coaches on how heat impacts their individual (thermo)physiological responses and, based on these data, advise which personalized countermeasures (i.e. heat acclimation, cooling interventions, rehydration plan) can be taken to allow safe and maximal performance in the challenging environmental conditions of the Tokyo 2020 Olympic and Paralympic Games., (© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Objective: To estimate the incidence and recurrence rates of acute hamstring injuries in all levels of soccer., Design: Epidemiology systematic review., Literature Search: We searched the PubMed (including MEDLINE), CINAHL, SPORTDiscus, Embase, and Cochrane Central Register of Controlled Trials electronic databases., Study Selection Criteria: We included prospective studies of all levels of adult soccer players that registered acute hamstring injuries and provided a description of incidence of acute hamstring injuries per 1000 playing hours (or available data to calculate this)., Data Synthesis: Due to heterogeneity, we synthesized the data descriptively., Results: Thirteen studies including 3868 players met the inclusion criteria. Two of 13 included studies reported on hamstring injuries in women, and all reported the same in men. The incidence of acute hamstring injury ranged from 0.3 to 0.5 per 1000 exposure hours in women and 0.3 to 1.9 per 1000 exposure hours in men. Hamstring injuries accounted for 5% to 15% of all soccer-related injuries. Hamstring injury recurrence rates ranged from 4% to 68%, depending on the injury definition. Certainty of evidence ranged from moderate to very low., Conclusion: The incidence of acute hamstring injury in soccer was 0.3 to 1.9 per 1000 exposure hours. The recurrence rate was 4% to 68%. The strength of the evidence was limited by a lack of methodological rigor, the use of varying definitions for acute hamstring injury, and heterogeneous methods of reporting on acute hamstring injuries. J Orthop Sports Phys Ther 2021;51(1):27-36. Epub 11 Dec 2020. doi:10.2519/jospt.2021.9305 .

Despite an elevated recovery need, research indicates that athletes often exhibit relatively poor sleep. Timing and consolidation of sleep is driven by the circadian system, which requires periodic light-dark exposure for stable entrainment to the 24-hour day, but is often disturbed due to underexposure to light in the morning (e.g. low-level indoor lighting) and overexposure to light in the evening (e.g. environmental and screen-light). This study examined whether combining fixed sleep schedules with light regulation leads to more consolidated sleep. Morning light exposure was increased using light-emitting goggles, whereas evening light exposure was reduced using amber-lens glasses. Using a within-subject crossover design, twenty-six athletes (14 female, 12 male) were randomly assigned to start the intervention with the light-regulation-week or the no light-regulation-week. Sleep was monitored by means of sleep diaries and actigraphy. Due to low protocol adherence regarding the fixed sleep-wake schedules, two datasets were constructed; one including athletes who kept a strict sleep-wake schedule ( N  = 8), and one that also included athletes with a more lenient sleep-wake schedule ( N  = 25). In case of a lenient sleep-wake schedule, light regulation improved self-reported sleep onset latency (Δ SOL = 8 min). This effect was stronger (Δ SOL = 17 min) and complemented by enhanced subjective sleep quality in case of a strict sleep-wake schedule. None of the actigraphy-based estimates differed significantly between conditions. To conclude, light regulation may be considered a potentially effective strategy to improve subjective sleep, but less obtrusive methods should be explored to increase protocol compliance.

To assess the impact of lower-leg muscle activity during the stance phase of running on the development of medial tibial stress syndrome (MTSS), in 123 healthy participants (18.2 ± 0.8 years), dynamic and static foot posture, and soleus and tibialis anterior muscle activity during the stance phase of running were measured before a 17-week track- and field-course. After the course, MTSS was identified in 20.5% of the participants. MTSS participants had a higher body mass (ES = 1.13), body mass index (BMI) (ES = 1.31), lower previous vigorous physical activity level (ES = 0.84) and VO 2max (ES = 0.61), greater dynamic foot pronation (ES = 0.66), higher soleus peak EMG amplitude during the absorption (ES = 0.60) and propulsion phases (ES = 0.56) of running, and a history of MTSS (OR = 6.38) ( p < 0.05). Stepwise logistic regression showed BMI, dynamic foot index, soleus peak EMG amplitude during propulsion, MTSS history and previous vigorous physical activity were predictors of MTSS. The model predicted 96.6% of the healthy participants and 56.5% of the MTSS participants and correctly classified 88.4% of overall cases. Coaches and sports-medicine professionals that screen for injury risk should consider adopting a comprehensive evaluation that includes these parameters.

Background: Despite reported injury rates of up to 3 per 1000 hours exposure, there are no evidence-based prevention programmes in tennis., Purpose: To evaluate the effectiveness of an e-health prevention programme for reducing tennis injury prevalence., Study Design: Two-arm, researcher-blinded randomised controlled trial., Methods: Adult tennis players of all playing levels were randomised in an unsupervised programme lasting 12 weeks (TennisReady group or control group). The primary outcome was the overall injury prevalence over a 16-week period, measured at 2 weekly intervals with the Oslo Sports and Trauma Research Centre questionnaire. Estimates for the primary outcome and associated 95% CIs were obtained using generalised estimating equation models. Secondary outcome scores included prevalence of substantial injuries, overall incidence, adherence and time-loss injuries., Results: A total of 579 (83%) (TennisReady n=286, control n=293) participants were included in the primary analysis. The mean injury prevalence was 37% (95% CI 33% to 42%) in the TennisReady vs 38% (95% CI 34% to 42%) in the control group (adjusted p-value 0.93). The prevalence of substantial injuries was 11% (95% CI 9% to 14%) in the TennisReady vs 12% (95% CI 9% to 15%) in the control group (p value of 0.79). Analysis of the secondary outcome scores showed no difference between groups. The mean prevalence rates between high (8%) and low (92%) adherent groups were 32% (95% CI 23% to 44%) and 37% (95% CI 33% to 42%), respectively (p value 0.36)., Conclusion: Providing an unsupervised e-health tennis-specific exercise programme did not reduce the injury rates and should not be implemented., Trial Registration Number: NTR6443., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

About 40% of postmenopausal women have decreased sexual desire, causing distress. Estrogen therapy attenuates vaginal complaints but has no effect on sexual desire. Although sexual function has been linked to testosterone, there is no clear relation between sexual desire and circulating levels of testosterone. Nevertheless, treatment with transdermal (patch) testosterone improved sexual function in several randomized controlled trials. Women with hypoactive sexual desire disorder who were treated with testosterone reported more satisfying sexual episodes and sexual desire compared with the placebo group. Adverse effects were mild. However, there is no testosterone drug designed for women available on the European market. Consequently, women who opt for testosterone treatment have to use preparations made for men with a high drug concentration. Adequate dosage for women is therefore challenging. A trial of 5 mg transdermal testosterone (gel or cream) daily or less has been suggested, followed by close monitoring of side effects and hormone level., (© 2020 Nordic Federation of Societies of Obstetrics and Gynecology.)

Background: Stem cell therapy is an emerging treatment for tendon disorders., Purpose: To systematically review the efficacy of stem cell therapy for patients with tendon disorders., Study Design: Systematic review; Level of evidence, 4., Methods: MEDLINE/PubMed, EMBASE, CINAHL, CENTRAL, PEDro, and SPORTDiscus; trial registers; and gray literature were searched to identify randomized controlled trials (RCTs) and non-RCTs, cohort studies, and case series with 5 or more cases. Studies investigating any type of stem cell therapy for patients with tendon disorders were eligible if they included patient-reported outcome measures or assessed tendon healing. Risk of bias was assessed through use of the Cochrane risk of bias tools., Results: This review included 8 trials (289 patients). All trials had moderate to high risk of bias (level 3 or 4 evidence). In Achilles tendon disorders, 1 trial found that allogenic-derived stem cells led to a faster recovery compared with platelet-rich plasma. Another study found no retears after bone marrow-derived stem cell therapy was used in addition to surgical treatment. There were 4 trials that studied the efficacy of bone marrow-derived stem cell therapy for rotator cuff tears. The controlled trials reported superior patient-reported outcomes and better tendon healing. A further 2 case series found that stem cell therapy improved patient-reported outcomes in patients with patellar tendinopathy and elbow tendinopathy., Conclusion: Level 3 evidence is available to support the efficacy of stem cell therapy for tendon disorders. The findings of available studies are at considerable risk of bias, and evidence-based recommendations for the use of stem cell therapy for tendon disorders in clinical practice cannot be made at this time. Stem cell injections should not be used in clinical practice given the lack of knowledge about potentially serious adverse effects., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This systematic review was supported by the Dutch National Olympic Committee. However, this funding had no influence on the collection, analysis, interpretation, and writing of the current manuscript. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Introduction: Platelet-rich plasma (PRP) is a potentially efficacious treatment for ankle osteoarthritis (OA), but its use has not been examined in high-quality studies. Systematic reviews show that PRP injections significantly decrease pain and improve function in patients with knee OA. Ankle OA is more common than hip or knee OA in the young active population; with a prevalence of 3.4%.PRP injections in ankle OA are shown to be safe and improve quality of life over time, but no randomised controlled trial has been conducted. Our randomised controlled trial will evaluate the efficacy of PRP injections for symptom reduction and functional improvement, compared with placebo, in the treatment of ankle (talocrural) OA., Methods and Analysis: We will conduct the Platelet-Rich plasma Injection Management for Ankle OA study: a multicentre, randomised, placebo-controlled trial. One hundred patients suffering from ankle OA will be randomised into two treatment groups: PRP injection or placebo (saline) injection. Both groups will receive two injections of PRP or placebo at an interval of 6 weeks. Primary outcome is the American Orthopaedic Foot and Ankle Society score at 26 weeks. Secondary outcomes determined at several follow-up moments up to 5 years, include Ankle Osteoarthritis Score, Foot and Ankle Outcome Score, pain subscale of (0-40), Visual Analogue Scale score (0-100), Ankle Activity Score (0-10), subjective patient satisfaction Short Form Health Survey-36, Global Attainment Scaling and the EuroQol-5 dimensions-3 levels utility score. A cost-effectiveness analysis will be performed at 1 year., Ethics and Dissemination: The study is approved by the Medical Ethics Review Committee Amsterdam Medical Center, the Netherlands (ABR 2018-042, approved 23 July 2018) and registered in the Netherlands trial register (NTR7261). Results and new knowledge will be disseminated through the Dutch Arthritis Association (ReumaNederland), Dutch patient federation, conferences and published in a scientific peer-reviewed journal., Trial Registration Number: NTR7261., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.)

The pathology of medial tibial stress syndrome (MTSS) is unknown. Studies suggest that MTSS is a bony overload injury, but histological evidence is sparse. The presence of microdamage, and its potential association with targeted remodeling, could provide evidence for the pathogenesis of MTSS. Understanding the pathology underlying MTSS could contribute to effective preventative and therapeutic interventions for MTSS. Our aim was to retrospectively evaluate biopsies, previously taken from the painful area in athletes with MTSS, for the presence of linear microcracks, diffuse microdamage and remodeling. Biopsies, previously taken from athletes with MTSS, were evaluated at the Department of Anatomy and Cell Biology at the Indiana University. After preparing the specimens by en bloc staining, one investigator evaluated the presence of linear microcracks, diffuse microdamage and remodeling in the specimens. A total of six biopsies were evaluated for the presence of microdamage and remodeling. Linear microcracks were found in 4 out of 6 biopsies. Cracking in one of these specimens was artefactual due to the biopsy procedure. No diffuse microdamage was seen in any of the specimens, and only one potential remodeling front in association with the microcracks. We found only linear microcracks in vivo in biopsies taken from the painful area in 50% of the athletes with MTSS, consistent with the relationship between linear cracks and fatigue-associated overloading of bone. The nearly universal absence of a repair reaction was notable. This suggests that unrepaired microdamage accumulation may underlie the pathophysiological basis for MTSS in athletes.

Objectives: Elite athletes are at high risk for poor oral health. A screening program to assess oral health and create dental awareness can improve oral health among elite athletes but has not been performed in the Netherlands before. We summarize the first results from such a screening conducted in Dutch elite athletes of the Nederlands Olympisch Committee*Nederlandse Sport Federatie (NOC*NSF, Dutch Olympic Committee)., Methods: In this cross-sectional study, 800 Dutch athletes eligible for the Olympic and Paralympic Games in Rio de Janeiro 2016 were invited to a costless and voluntary oral examination. The decayed, missing, and filled teeth-index (DMFT), the basic erosive wear examination (BEWE) and the Dutch Periodontal Screening-index (DPSI) were used to evaluate athlete's oral health. Information on sociodemographic variables and sport performance were collected in questionnaires., Results: In total, 116 Dutch elite athletes were included in the study. The median (90%-range) DMFT-score was 3.0 (0.0-16.0), the median BEWE-score was 2.0 (0.0-10.0), and the mean± SD DPSI-score was 2.0 ± 0.73. Oral health-related quality of life was generally high, although only 28.2% of the athletes reported never having problems with their dentition or mouth. In 43% of the athlete's clinical findings were reported which needed a direct referral to the general dentist., Conclusion: Oral health in this subsample of Dutch elite athletes was surprisingly affected as almost half of them needed dental treatment. Further research is needed to allow conclusions about oral health in Dutch elite athletes more broadly. However, regular screening of oral health incorporated into the general preventive health care of elite athletes is necessary to ensure athletes are fully healthy during competitions like the Olympic and Paralympic Games.

Performance capacity in athletes depends on the ability to recover from past exercise. While evidence suggests that athletic performance decreases following (partial) sleep deprivation and increases following sleep extension, it is unclear to which extent natural variation in sleep impacts performance. Sleep quantity and, for the first time, sleep stages were assessed among 98 elite athletes on three non-consecutive nights within a 7-day monitoring period, along with performance tests that were taken on standardized times each following morning. Performance assessment included psychomotor performance (10-minute psychomotor vigilance task) and sport-specific tests of fine (e.g., accuracy) and gross motor skills (e.g., endurance, power). Mixed-effects models were employed to assess the effect of sleep quantity (total sleep time (TST), sleep onset latency (SOL), wake after sleep onset, sleep efficiency) and sleep stage duration (light, deep, REM) on performance. Average TST was 7:30 ± 1:05 hours, with a mean variation of 57 minutes across days. Longer TSTs were associated with faster reaction times (p = 0.04). Analyses indicated small and inconsistent effects of sleep quantity (TST, SOL) and sleep staging (light sleep) on gross motor performance, and no effects on fine motor skill performance. Results indicate that natural variation in sleep quantity impacts psychomotor vigilance to a greater extent than athletic performance. Small or absent effects can be a consequence of the rather small variation in non-manipulated sleep. It is suggested that one night of compromised sleep may not be immediately problematic, but that more extreme sleep loss or accumulated sleep debt may have more severe consequences.

Background: Acute hamstring injury that includes intramuscular tendon injury has been suggested to be associated with increased reinjury risk. These observations were based on a relatively small number of retrospectively analysed cases., Objective: To determine whether intramuscular tendon injury is associated with higher reinjury rates in acute hamstring injury., Methods: MRIs of 165 athletes with an acute hamstring injury were obtained within 5 days of injury. Treatment consisted of a standardised criteria-based rehabilitation programme. Standardised MRI parameters and intramuscular tendon injury, the latter subdivided into tendon disruption and waviness, were scored. We prospectively recorded reinjuries, defined as acute onset of posterior thigh pain in the same leg within 12 months after return to play., Results: Participants were predominantly football players (72%). Sixty-four of 165 (39%) participants had an index injury with intramuscular hamstring tendon disruption, and waviness was present in 37 (22%). In total, there were 32 (19%) reinjuries. There was no significant difference (HR: 1.05, 95% CI 0.52 to 2.12, P=0.898) in reinjury rate between index injuries with intramuscular tendon disruption (n=13, 20%) and without tendon disruption (n=19, 20%). There was no significant difference in reinjury rate (X²(1)=0.031, P=0.861) between index injuries with presence of waviness (n=7, 19%) and without presence of waviness (n=25, 20%)., Conclusion: In athletes with an acute hamstring injury, intramuscular tendon injury was not associated with an increased reinjury rate within 12 months after return to play., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: The majority of sporting injuries are clinically diagnosed using history and physical examination as the cornerstone. There are no studies supporting the reliability of making a clinical diagnosis of medial tibial stress syndrome (MTSS)., Aim: Our aim was to assess if MTSS can be diagnosed reliably, using history and physical examination. We also investigated if clinicians were able to reliably identify concurrent lower leg injuries., Methods: A clinical reliability study was performed at multiple sports medicine sites in The Netherlands. Athletes with non-traumatic lower leg pain were assessed for having MTSS by two clinicians, who were blinded to each others' diagnoses. We calculated the prevalence, percentage of agreement, observed percentage of positive agreement (Ppos), observed percentage of negative agreement (Pneg) and Kappa-statistic with 95%CI., Results: Forty-nine athletes participated in this study, of whom 46 completed both assessments. The prevalence of MTSS was 74%. The percentage of agreement was 96%, with Ppos and Pneg of 97% and 92%, respectively. The inter-rater reliability was almost perfect; k=0.89 (95% CI 0.74 to 1.00), p<0.000001. Of the 34 athletes with MTSS, 11 (32%) had a concurrent lower leg injury, which was reliably noted by our clinicians, k=0.73, 95% CI 0.48 to 0.98, p<0.0001., Conclusion: Our findings show that MTSS can be reliably diagnosed clinically using history and physical examination, in clinical practice and research settings. We also found that concurrent lower leg injuries are common in athletes with MTSS., Competing Interests: Competing interests: MW received a small grant from The Dutch National Olympic Committee during the course of this study for the performance of a prospective cohort study in athletes at risk for medial tibial stress syndrome (MTSS), investigating the relation between local tibial bone changes and MTSS., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objectives: Sleep is essential for recovery and performance in elite athletes. While it is generally assumed that exercise benefits sleep, high training load may jeopardize sleep and hence limit adequate recovery. To examine this, the current study assessed objective sleep quantity and sleep stage distributions in elite athletes and calculated their association with perceived training load., Design: Mixed-methods., Methods: Perceived training load, actigraphy and one-channel EEG recordings were collected among 98 elite athletes during 7 consecutive days of regular training., Results: Actigraphy revealed total sleep durations of 7:50±1:08h, sleep onset latencies of 13±15min, wake after sleep onset of 33±17min and sleep efficiencies of 88±5%. Distribution of sleep stages indicated 51±9% light sleep, 21±8% deep sleep, and 27±7% REM sleep. On average, perceived training load was 5.40±2.50 (scale 1-10), showing large daily variability. Mixed-effects models revealed no alteration in sleep quantity or sleep stage distributions as a function of day-to-day variation in preceding training load (all p's>.05)., Conclusions: Results indicate healthy sleep durations, but elevated wake after sleep onset, suggesting a potential need for sleep optimization. Large proportions of deep sleep potentially reflect an elevated recovery need. With sleep quantity and sleep stage distributions remaining irresponsive to variations in perceived training load, it is questionable whether athletes' current sleep provides sufficient recovery after strenuous exercise., (Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Treatment of total ruptures of adductor longus is challenging in professional sports. Time for return to pre-injury level as well as re-injury rates are of concern and surgical and conservative treatment approaches are debated; yet no consensus approach described for professional athletes. We present a case of a professional soccer player who experienced a rupture in his left adductor longus proximal tendon during a game and was treated conservatively. This case was followed-up during clinical assessment, imaging and strength testing until and after return to play. Primary outcome measure was the return to standard play condition at his pre-injury level without any functional deficits, measured by isokinetic testing. Second outcome measure was the recurrence. No recurrence was observed during the first year of follow-up. Total ruptures are very challenging for both the physician and the player to make a quick decision due to minimal or lack of pain. Functional outcomes are almost identical although operative treatments need longer time to return to play. This case report adds another example to the literature of a successful return to play after non-operative treatment of adductor longus rupture at elite level soccer.

Background: Involvement of the intramuscular (central) tendon in acute hamstring injuries, as detected on magnetic resonance imaging (MRI), may prolong recovery times. To date, it is unclear whether hamstring injuries exhibiting intramuscular tendon involvement can be identified though routine clinical examinations that assess flexibility and strength., Purpose: To test whether MRI-detected intramuscular tendon involvement could be identified by a clinical assessment of muscle strength and flexibility., Study Design: Case-control study; Level of evidence, 3., Methods: Participants were drawn from a multicenter randomized controlled trial on the effect of platelet-rich plasma in acute hamstring injuries. Clinical parameters assessed within 5 days of injury were active knee extension and passive straight-leg raise for hamstring flexibility and isometric knee flexion force with 15° and 90° of knee flexion. Also, 1.5-T MRI of the thigh was performed within 5 days of injury and was evaluated for the presence of different types of intramuscular tendon involvement. One-way analysis of variance was used to determine whether clinical parameters could discriminate injuries with intramuscular tendon involvement from those without such involvement., Results: A total of 74 acute hamstring injuries were included, with 52 (70.3%) injuries affecting the myotendinous junction. Injuries exhibiting intramuscular tendon discontinuity on MRI had an increased mean absolute flexibility deficit for active knee extension (20.4° ± 14.9° vs 10.7° ± 9.0°, respectively; P = .006) and decreased mean strength at 15° (62.2 ± 26.7 N vs 76.6 ± 22.5 N, respectively; P = .05) compared with injuries without intramuscular tendon discontinuity. Flexibility and strength showed major overlap and variance among injuries with and without intramuscular tendon involvement., Conclusion: Hamstring flexibility and strength cannot be used to discriminate the presence of intramuscular tendon involvement., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study was supported by the Royal Dutch Football Association and Arthrex Medizinische Instrumente. ††References 3, 4, 7, 8, 14, 17, 24, 28, 33, 35.

Background: A challenge for sports physicians is to estimate the risk of a hamstring re-injury, but the current evidence for MRI variables as a risk factor is unknown., Objective: To systematically review the literature on the prognostic value of MRI findings at index injury and/or return to play for acute hamstring re-injuries., Data Sources: Databases of PubMed, Embase, MEDLINE, Scopus, CINAHL, Google Scholar, Web of Science, LILACS, SciELO, ScienceDirect, ProQuest, SPORTDiscus and Cochrane Library were searched until 20 June 2016., Study Eligibility Criteria: Studies evaluating MRI as a prognostic tool for determining the risk of re-injury for athletes with acute hamstring injuries were eligible for inclusion., Data Analysis: Two authors independently screened the search results and assessed risk of bias using standardised criteria from a consensus statement. A best-evidence synthesis was used to identify the level of evidence. Post hoc analysis included correction for insufficient sample size., Results: Of the 11 studies included, 7 had a low and 4 had a high risk of bias. No strong evidence for any MRI finding as a risk factor for hamstring re-injury was found. There was moderate evidence that intratendinous injuries were associated with increased re-injury risk. Post hoc analysis showed moderate evidence that injury to the biceps femoris was a moderate to strong risk factor for re-injury., Conclusion: There is currently no strong evidence for any MRI finding in predicting hamstring re-injury risk. Intratendinous injuries and biceps femoris injuries showed moderate evidence for association with a higher re-injury risk., Systematic Review Registration: Registration in the PROSPERO International prospective register of systematic reviews was performed prior to study initiation (registration number CRD42015024620)., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: Stem cell injection for knee osteoarthritis (KOA) is an emerging new therapy, and we aimed to review its evidence of efficacy., Design: Systematic review., Eligibility Criteria: Criteria for eligibility were randomised controlled trials (RCTs) and non-RCT on the efficacy of stem cell injections in KOA. All references were checked for missed articles., Data Sources: MEDLINE, EMBASE, CINAHL, Web of Science, Cochrane Library, PEDro and SPORTDiscus were searched. A grey literature search was performed. No restrictions were imposed to our search strategy., Risk of Bias and Data Synthesis: Risk of bias was assessed using the Cochrane risk of bias tool. Descriptive synthesis was performed using the levels of evidence according to the Oxford Levels of Evidence., Results: Five RCTs and one non-RCT were found. Bone-marrow-derived stem cells, adipose-derived mesenchymal stem cells and peripheral blood stem cells were used. All trials were at high risk of bias, resulting in level-3 evidence. All five RCTs reported superior efficacy for patient-reported outcomes (Visual Analogue Scale, Western Ontario and McMaster Universities Arthritis Index, Tegner, Lysolm, International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score, Lequesne) compared with controls at final follow-up (range 24-48 months). Superior radiological outcomes were found favouring stem cell injection. Superior histological outcomes and/or improved arthroscopically scored healing rates were reported in two trials. No serious adverse events were reported., Conclusion: Six trials with high risk of bias showed level-3 or level-4 evidence in favour of stem cell injections in KOA. In the absence of high-level evidence, we do not recommend stem cell therapy for KOA., Competing Interests: Competing interests: HP received a grant from the Dutch National Olympic Committee and the Sports Physicians Group, Department of Sports Medicine, OLVG West, Amsterdam for the realisation of this review. The Dutch National Olympic Committee and the Sports Physicians Group had no influence in the performance of this review. HP and MW report receiving grants from the Dutch National Olympic Committee outside the submitted work., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Introduction: Stem cells have emerged as a new treatment option for tendon disorders. We systematically reviewed the current evidence for stem cell therapy in tendon disorders., Methods: Randomised and non-randomised controlled trials, cohort studies and case series with a minimum of 5 cases were searched in MEDLINE, CENTRAL, EMBASE, CINAHL, PEDro and SPORTDiscus. In addition, we searched grey literature databases and trial registers. Only human studies were included and no time or language restrictions were applied to our search. All references of included trials were checked for possibly eligible trials. Risk of bias assessment was performed using the Cochrane risk of bias tool for controlled trials and the Newcastle-Ottawa scale for case series. Levels of evidence were assigned according to the Oxford levels of evidence., Results: 4 published and three unpublished/pending trials were found with a total of 79 patients. No unpublished data were available. Two trials evaluated bone marrow-derived stem cells in rotator cuff repair surgery and found lower retear rates compared with historical controls or the literature. One trial used allogenic adipose-derived stem cells to treat lateral epicondylar tendinopathy. Improved Mayo Elbow Performance Index, Visual Analogue Pain scale and ultrasound findings after 1-year follow-up compared with baseline were found. Bone marrow-derived stem cell-treated patellar tendinopathy showed improved International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score subscales and Tegner scores after 5-year follow-up. One trial reported adverse events and found them to be mild (eg, swelling, effusion). All trials were at high risk of bias and only level 4 evidence was available., Conclusions: No evidence (level 4) was found for the therapeutic use of stem cells for tendon disorders. The use of stem cell therapy for tendon disorders in clinical practice is currently not advised., Competing Interests: Competing interests: HP and MW received a grant from the Dutch National Olympic Committee for the realisation of this review. HP reports receiving grants from the Dutch National Olympic Committee and the Sports Physician group, Department of Sports Medicine, OLVG West, Amsterdam, outside the submitted work., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Objective: To evaluate the effectiveness of a combined treatment of focused shockwave therapy (ESWT) and eccentric training compared with sham-shockwave therapy (placebo) and eccentric training in participants with patellar tendinopathy (PT) after 24 weeks., Design: Randomized controlled trial., Setting: Sports medicine departments of a university hospital and a general hospital in the Netherlands., Participants: Fifty-two physically active male and female participants with a clinical diagnosis of PT (mean age: 28.6 years; range, 18-45) were randomly allocated to the ESWT (n = 22) or sham shockwave (n = 30)., Interventions: Extracorporeal shockwave therapy and sham shockwave were applied in 3 sessions at 1-week intervals with a piezoelectric device. All participants were instructed to perform eccentric exercises (3 sets of 15 repetitions twice a day) for 3 months on a decline board at home., Main Outcome Measures: The Victorian Institute of Sport Assessment-Patella (VISA-P) scores (primary), pain scores during functional knee loading tests, and Likert score (secondary) were registered at baseline and at 6, 12, and 24 weeks after the start with the ESWT or sham-shockwave treatment., Results: No significant differences for the primary and secondary outcome measures were found between the groups. In the ESWT/eccentric group, the VISA-P increased from 54.5 ± 15.4 to 70.9 ± 17.8, whereas the VISA-P in the sham-shockwave/eccentric group increased from 58.9 ± 14.6 to 78.2 ± 15.8 (between-group change in VISA-P at 24 weeks -4.8; 95% confidence interval, -12.7 to 3.0, P = 0.150)., Conclusions: This study showed no additional effect of 3 sessions ESWT in participants with PT treated with eccentric exercises. The results should be interpreted with caution because of small sample size and considerable loss to follow-up, particularly in the ESWT group.

Objectives: Medial tibial stress syndrome (MTSS) is one of the most common sporting injuries. As of yet, the development of effective therapeutic interventions to treat MTSS is hindered by the fact that its pathology is unknown. Our aim was to explore the pathology of MTSS, by assessing whether the presence of MTSS is related to periosteal, bony or tendinous abnormalities in the lower leg., Design: Case-control study., Methods: Participants with MTSS and athletic control participants were recruited from the same (high-risk) base population. Musculoskeletal ultrasonography was performed on the posteromedial tibial border and deep plantar flexor muscles by an experienced radiological specialist who was blinded to group membership. Associations between MTSS and tissue abnormalities were expressed in odds ratios (OR)., Results: A total of 42 participants, 15 MTSS cases and 27 control athletes completed the study. Overall, periosteal and tendinous abnormalities were common in cases with and without MTSS. Periosteal edema was present in 8 (53.3%) MTSS cases and in 10 (37.0%) control athletes, in specific painful spots in the distal 2/3 of the posteromedial tibial border OR=1.9 (95% CI 0.54-6.99, p=0.35). Also, tendinous abnormalities in the tibialis posterior muscle were frequently seen in MTSS cases (N=7, 46.7%) and in control athletes (N=13, 48.1%) (OR=0.97, 95% CI 0.27-3.51, p=0.96). No bone abnormalities were observed in either group., Conclusions: Periosteal and tendinous findings seem to be common in both athletes with and without MTSS, and consequently are not associated with MTSS., (Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Introduction: No reports have been published on the results of corticosteroid injections for medial tibial stress syndrome (MTSS)., Case Presentation: The authors present 2 cases of women with MTSS who showed atrophy and depigmentation of the skin after pretibial corticosteroid injections. Case 1 is an 18-y-old woman presenting with pain in her lower leg for 12 mo. No improvement was noticed after conservative treatment, so she received local injections with corticosteroids. Five months later physical examination showed tissue atrophy and depigmentation around the injection sites. Case 2 is a 22-y-old woman who presented with pain in both lower legs for 24 mo. Several conservative treatment options failed, so she received local injections with corticosteroids. Physical examination revealed tissue atrophy and depigmentation around the injection sites., Conclusion: No positive effect of injections with corticosteroids was found in 2 cases of MTSS. Furthermore, considerable tissue atrophy and hypopigmentation of the skin was observed.