Risk Factors for Knee Injuries in Children 8 to 15 Years

Youth sport participation, injury history, and current physical activity among young adults

Objective: To examine the interaction between high school (HS) sports participation and injury history with current moderate-to-vigorous physical activity (MVPA) among young adults. Participants: Participants (N = 236) were 18-25 years old, not currently injured, and reported no physical activity limitations. Methods: Participants completed online demographic, injury history, and physical activity surveys. A two-way analysis of covariance was used to test the interaction between HS athlete status and previous injury severity on current self-reported MVPA. Results: Participants were 22.2 ± 2.1 years, primarily White (81.8%) or Asian (6.4%), and female (77.5%). After including body mass index and race as covariates, there was a statistically significant interaction between HS athlete status and previous injury history such that current MVPA was higher among former HS athletes compared to HS recreational/nonathletes when individuals reported no injuries or mild injury severity. MVPA was similar across athlete status groups when participants reported high levels of injury severity. Conclusions: Future studies should examine whether young adults who have experienced multiple and/or severe injuries as competitive HS athletes have unique physical activity barriers.

Development of a tool to support general practitioners to help adolescents with knee pain: an analysis using the Theoretical Domains Framework

AIM

Using the Theoretical Domains Framework (TDF) and COM-B model, this study aimed to determine the facilitators to a support tool for adolescent non-traumatic knee pain in general practice.

BACKGROUND

Many children and adolescents with non-traumatic knee pain consult their general practice. Currently, there are no tools to support general practitioners in the diagnosis and management of this group. There is a need to identify behavioural targets that would facilitate further development and implementation of such a tool.

METHODS

This study was designed as a qualitative study using focus group interviews with 12 medical doctors working in general practice. The semi-structured focus group interviews conducted online and followed an interview guide based on the TDF and COM-B model. Data were analysed via thematic text analysis.

FINDINGS

One of the biggest challenges from the general practitioner's perspective was how to manage and guide adolescents with non-traumatic knee pain. The doctors had doubts in their capability to diagnose knee pain and saw opportunity to help structure the consultation. The doctors felt motivated to use a tool but considered access a potential barrier. Increasing opportunity and motivation by creating access in the community among general practitioners was considered important. We identified several barriers and facilitators for a support tool for the management of adolescent non-traumatic knee pain in general practice. To align with user needs, future tools should support diagnostic workup, structure the consultation and be easily available among doctors working in general practice.

Knee pain in young sports players aged 6-15 years: a cross-sectional study in Japan

BACKGROUND

Knee is the most commonly injured part of the body in young athletes. Knee pain in several studies have been seen to be more prevalent in active adolescents compared to inactive, although common in both groups. Nevertheless, few studies with large sample size have been published reporting the difference of the prevalence of knee pain for each sport among young sports players. This study investigated the point prevalence of knee pain among young sports players aged 6-15 years old according to age, sex, and sports discipline. Furthermore, this study investigated the association between knee pain and sports discipline among young sports players.

METHODS

A cross-sectional study was conducted using a self-reported questionnaire on young sports players aged 6-15 years from the Miyagi Amateur Sports Association. Multivariable logistic regression models were used to examine the association between knee pain and sports discipline and were adjusted for age, sex, body mass index (BMI), training days per week, and training hours per weekday and weekend.

RESULTS

A total of 7234 young sports players were included. The point prevalence of knee pain was 10.9%. Females (13.3%) had more knee pain than males (9.8%). Young, 13-year-old sports players had the highest prevalence of knee pain (19.1%). The multivariable analysis showed that the highest odds ratio [95% confidence interval] was observed for handball players (2.42 [1.01-5.81]). In addition, hand ball, mini-basketball (odds ratio 1.85; 95% CI 1.38-2.47), and basketball (odds ratio 1.66; 95% CI 1.23-2.26) were significantly associated with knee pain, compared with football. The lowest odds ratio was observed for swimming (0.34 [0.05-2.54]), followed by karate (odds ratio 0.38; 95% CI 0.16-0.89) and baseball (odds ratio 0.47; 95% CI 0.35-0.64).

CONCLUSION

The prevalence of knee pain among young athletes differed according to age, sex, and sports discipline. Their parents and clinicians should recognize this information to manage knee pain among young sports players.

Association of sports sampling and training frequency with injury among school-age athletes in Japan

BACKGROUND

This study evaluated the status of sports participation and training frequency during school years to identify related factors for injuries in the general Japanese population.

METHODS

A total of 1,533 adult participants (762 males, 771 females) retrospectively completed a questionnaire assessing sports participation (single/multisport), training frequency (weekly days of sports participation), and injury history (acute and overuse) at each stage of school (elementary, junior high, and high school).

RESULTS

In total, 41.1% of participants reported playing multiple sports in elementary school; this rate decreased to 17.4% in junior high school and 8.9% in high school. Weekly days of sports participation were associated with almost all injuries at each age. Participants who still played multiple sports in junior high school had fewer overuse injuries in junior high school and high school (P = 0.017; odds ratio (OR) = 0.69; 95% confidence interval (CI) = 0.51-0.94; P = 0.006, OR = 0.66, 95% CI, 0.49-0.89, respectively). The ratio for sports sampling differed between elementary school and older ages. This trend was associated with the prevalence of overuse injuries.

CONCLUSION

Promoting sports sampling through junior high school ages and controlling the training frequency may decrease the occurrence of injuries in young athletes.

Development and validation of the Sorting non-trauMatIc adoLescent knEe pain (SMILE) tool - a development and initial validation study

BACKGROUND

Despite the commonality of adolescent knee pain, there are no tools to support medical doctors to correctly diagnose knee pain. This study aimed to develop and evaluate a support tool for diagnosing the most common types of non-traumatic adolescent knee pain.

METHOD

A systematic search on Medline identified the literature on clinical tests and diagnoses of adolescent knee pain. The search was supplemented by textbooks and transformed into a diagnostic flowchart based on onset, symptoms, and pain localisation. This tool was revised based on feedback from general practitioners and experts in sports medicine. The tool was evaluated on two separate days with blinded assessors. Overall, 27 participants (aged 10-17 years) with non-traumatic knee pain were included. All participants were diagnosed by medical doctors or medical students, without and with the use of the tool. Diagnoses were compared to a gold standard (expert clinician). An interview to inform optimisations of the tool was performed with the assessors. Percentage agreement with the gold standard, and Kappa statistic for interrater reliability were calculated.

RESULTS

The final tool improved diagnostic agreement with the gold standard from 22.7% (95% CI 10.3-35.1) to 77.3% (95% CI 64.9-89.7). Inter-rater reliability increased from poor agreement k = - 0.04 (95% CI, - 0.12-0.04) to moderate agreement k = 0.56 (95% CI, 0.40-0.72).

CONCLUSION

This simple diagnostic tool is quick to use and may assist doctors in diagnosing non-traumatic knee pain in adolescents.

Prognostic factors for adolescent knee pain: an individual participant data meta-analysis of 1281 patients

ABSTRACT

Adolescent knee pain has a propensity for chronicity, impacting physical activity and health into adulthood. The aim of this study is to investigate prognostic factors in adolescents with knee pain using individual participant data (IPD) meta-analysis. Studies were identified through a systematic search and a collaborative group. We included IPD from prospective studies of adolescents (age 10-19 years) with nontraumatic knee pain (13 studies and 1516 adolescents with 1281 unique participants). Primary outcomes were pain intensity and function (Knee Injury and Osteoarthritis Outcome Score "Sport/Rec" subscale). Primary endpoint was 12 months. Risk of bias was appraised with Quality in Prognosis Studies tool. Harmonised IPD was analysed by multilevel modelling. Fifty-one percent reported knee pain after 12-months. Lower baseline pain frequency was associated with lower pain intensity at 12 months ("less than weekly"; 12 (95% confidence interval [CI] 7-17) and "monthly"; 15 (95% CI 9-22) points lower on a 100-point pain scale, compared with "almost daily pain"). Other factors most strongly associated with 1-year pain prognosis were lower quality of life (30, 95% CI 19-42 points per unit change in the EQ5D index score), female sex (8 points, 95% CI 4-12 higher compared with males), and bilateral pain (7, 95% CI 1-13 points higher pain). Similar factors were associated with function. Body mass index, pain sensitivity, and knee strength were not associated with prognosis of pain or function. Adolescent knee pain is associated with clinically relevant long-term pain and functional deficits. Self-reported characteristics may help identify those at risk of poor prognosis.

Statement on methods in sport injury research from the 1st METHODS MATTER Meeting, Copenhagen, 2019

High quality sports injury research can facilitate sports injury prevention and treatment. There is scope to improve how our field applies best practice methods—methods matter (greatly!). The 1st METHODS MATTER Meeting, held in January 2019 in Copenhagen, Denmark, was the forum for an international group of researchers with expertise in research methods to discuss sports injury methods. We discussed important epidemiological and statistical topics within the field of sports injury research. With this opinion document, we provide the main take-home messages that emerged from the meeting.

Statement on Methods in Sport Injury Research From the First METHODS MATTER Meeting, Copenhagen, 2019

High-quality sports injury research can facilitate sports injury prevention and treatment. There is scope to improve how our field applies best-practice methods-methods matter (greatly!). The first METHODS MATTER meeting, held in January 2019 in Copenhagen, Denmark, was the forum for an international group of researchers with expertise in research methods to discuss sports injury methods. We discussed important epidemiological and statistical topics within the field of sports injury research. With this opinion document, we provide the main take-home messages that emerged from the meeting. Meeting participants agreed that the definition of sport injury depends on the research question and context. It was considered essential to be explicit about the goal of the research effort and to use frameworks to illustrate the assumptions that underpin measurement and the analytical strategy. Complex systems were discussed to illustrate how potential risk factors can interact in a nonlinear way. This approach is often a useful alternative to identifying single risk factors. Investigating changes in exposure status over time is important when analyzing sport injury etiology, and analyzing recurrent injury, subsequent injury, or injury exacerbation remains challenging. The choice of statistical model should consider the research question, injury measure (eg, prevalence, incidence), type and granularity of injury data (categorical or continuous), and study design. Multidisciplinary collaboration will be a cornerstone for future high-quality sport injury research. Working outside professional silos in a diverse, multidisciplinary team benefits the research process, from the formulation of research questions and designs to the statistical analyses and dissemination of study results in implementation contexts. This article has been copublished in the British Journal of Sports Medicine and the Journal of Orthopaedic & Sports Physical Therapy. J Orthop Sports Phys Ther 2020;50(5):226-233. doi:10.2519/jospt.2020.9876.

Associations between sport participation and knee symptoms: a cross-sectional study involving 3053 undergraduate students

Background

While a number of studies have investigated knee symptoms among elite athletes, few have directly compared the association between engagement in different sports and knee symptoms among young adults in the general population. The current study aimed to investigate the relation between sports participation hours, type/ number of sports engaged, self-rated competitiveness and knee symptoms among undergraduates.

Methods

Undergraduates were invited to participate in a self-administered online survey through invitation emails. Respondents were instructed to provide demographic information (e.g., age, gender, sports participation hours, types of engaged sports, self-rated competitiveness in sports and anxiety level etc.) and to report knee symptoms (current, the last 7 days, the last 12 months, and lifetime). Multiple logistic regressions were conducted to investigate the association between sports participation and current knee symptoms.

Results

Of 17,552 invitees, 3744 responded to the survey. Valid data from 3053 respondents was used for analysis. Forty-four percent of the respondents engaged in sports regularly (≥once per week). Running, cross-training and swimming were the most frequently participated sports among the respondents. The current prevalence rate of knee symptoms was 6.4%. Hours spent participating in combat sports, soccer, yoga, and basketball participation hours were significantly associated with current knee symptoms. Respondents who rated themselves as “competitive” demonstrated a higher risk of having current knee symptoms than “recreational” players. Number of engaged sports was not associated with current knee symptoms among undergraduates.

Conclusions

Certain sports types were associated with current knee symptoms. Compared to self-rated “recreational” players, self-rated “competitive” players were more likely to have current knee symptoms. Students should take preventive measures to minimize their risk of developing knee symptoms, especially when participating in combat sports, soccer, yoga, and basketball, or engaging in sports at a highly competitive level.

Juvenile Osteochondritis Dissecans of the Trochlea: A Cohort Study of 34 Trochlear Lesions Associated With Sporting Activities That Load the Patellofemoral Joint

BACKGROUND

Juvenile osteochondritis dissecans (JOCD) lesions are rarely located in the trochlea and few studies have focused on the causes and outcomes of JOCD lesions in this part of the knee. The purpose of this study is to (1) evaluate the clinical characteristics and outcomes of patients who undergo surgery for JOCD in this unusual location as well as (2) assess the association between trochlear JOCD and participation in sporting activities that load the patellofemoral joint.

METHODS

We conducted a retrospective cohort study of 34 trochlear JOCD lesions in 30 patients. Cases that involved traumatic cartilage shear or patella instability were excluded. Preoperative and postoperative magnetic resonance images and x-rays were evaluated and demographic data, sports played, comorbidities, surgical procedures, and clinical data were extracted from medical records. A case-control cohort of 102 femoral condyle lesions was used to assess the correlation between sports played and lesion location.

RESULTS

The cohort comprised 34 consecutive trochlear JOCD lesions in 30 patients (26 males, 4 females). Average age at surgery was 13.8 years (9.3 to 18.0 y). In total, 27 (90%) patients were active, and of these active patients, soccer and basketball were the most common sports played. In the case-control comparison, the correlation between playing either basketball or soccer and the presence of a trochlear JOCD lesion was statistically significant (P=0.017). In total, 21 knees (62%) received operative treatment. Sixteen of the surgical patients underwent repair and fixation with bioabsorbable nails. The average length of clinical and radiographic follow-up was 21.1 months. All patients who underwent fixation showed radiographic and/or clinical indications of healing at most recent follow-up. Thirteen of the patients who underwent fixation were active, and all of these patients reported successful return to sports. Thirteen knees underwent nonoperative treatment, and the majority of these patients had limited follow-up.

CONCLUSIONS

We report a significant association between pediatric athletes who play basketball and soccer and the development of trochlear JOCD, suggesting that repetitive loading of the patellofemoral joint may play a role in the development of JOCD lesions. Patients with trochlear JOCD lesions were likely to undergo surgery, and repair and fixation of the lesions produced good outcomes at short-term follow-up.

LEVEL OF EVIDENCE

Level III-case-control study.

Generalised joint hypermobility increases ACL injury risk and is associated with inferior outcome after ACL reconstruction: a systematic review

Objectives

To investigate the association between generalised joint hypermobility (GJH) and ACL injury risk. Secondary aims involved evaluating associations between GJH and postoperative outcome (including graft-failure risk, knee laxity and patient-reported outcome). Furthermore, we aimed to compare the performance of different grafts in patients with GJH.

Methods

Databases MEDLINE/PubMed, EMBASE and the Cochrane Library were searched, including 2760 studies. Two reviewers independently screened studies for eligibility. A modified version of the MINORS score was applied for quality appraisal. Studies assessing GJH while reporting the risk of ACL injury and/or postoperative outcome were included.

Results

Twenty studies were included, using several different methods to determine GJH. There was consistent evidence showing that GJH is a risk factor for unilateral ACL injury in males, while in females, the results were conflicting. There was limited evidence associating GJH with increased knee laxity 5 years postoperatively. There was consistent evidence of inferior postoperative patient-reported outcome in patients with GJH. Moreover, there was limited yet consistent evidence indicating that patellar-tendon autografts are superior to hamstring-tendon autografts in patients with GJH in terms of knee laxity and patient-reported outcome. There was insufficient evidence to draw conclusions regarding the outcomes of bilateral ACL injury and graft failure.

Conclusions

In men, GJH was associated with an increased risk of unilateral ACL injury. Moreover, GJH was associated with greater postoperative knee laxity and inferior patient-reported outcome. Based on the available evidence, a patellar-tendon autograft appears to be superior to a hamstring-tendon autograft in patients with GJH. However, the included studies were heterogeneous and there is a need for consensus in the assessment of GJH within sports medicine.

Frequency and associated factors of poor knee alignment in young Brazilian volleyball players

Objectives: Poor knee alignment during the deceleration phase of closed kinetic chain movements, such as landings, is a relevant risk factor for injuries in sports. This study assessed the knee alignment and possible associated factors in young Brazilian volleyball athletes Methods: One hundred and seventeen athletes of both genders (9-19 years old) were assessed during a drop jump for the observation of knee alignment. Chi-square test was used to describe the association between poor knee alignment and: gender, age category (≤14 years and ≥15 years), sports experience, participation in competitions, the presence of knee pain during training, and history of lower limb injury Results: Seventy percent of athletes presented poor knee alignment, which was slightly associated with a sports experience lower than one year. Conclusion: Thus, considering the high number of volleyball practitioners and its strong presence in physical education classes, preventive measures should be adopted for young volleyball athletes of both genders, especially in the sports initiation phase.

Screening of the Maturity Status of the Tibial Tuberosity by Ultrasonography in Higher Elementary School Grade Schoolchildren

This study aimed to obtain screening data on the maturity status of the tibial tuberosity in schoolchildren of higher elementary school grades for risk management of Osgood-Schlatter disease (OSD). The maturity stages and cartilage thicknesses at the tibial tuberosity were determined by ultrasonography on the occasion of a school-based musculoskeletal examination for 124 grade 5-6 elementary schoolchildren, and their associations with the students' demographic characteristics and OSD were examined. The time-dependent changes of the maturity status of the tibial tuberosity were also examined in grade 5 students (n = 26) by a longitudinal survey. The cross-sectional survey showed that the epiphyseal stage was reached in 89% of girls and 35% of boys. The girls who had experienced menarche (n = 28) were all in the epiphyseal stage and had a decreased cartilage thickness (p = 0.004, after adjusting maturity stages). Students with OSD (n = 5) were all girls in the epiphyseal stage, and only two of them had an increased cartilage thickness. During the longitudinal survey, a marked increase in cartilage thickness from the previous measurement was observed in three boys (without clinical symptoms) and a girl who newly developed OSD. Two students with OSD without chronic pain had thin cartilage. In conclusion, for schoolchildren of higher elementary school grades, the risk of OSD is higher among girls with the epiphyseal stage. Cartilage thickness may not contribute to the diagnosis of OSD, since thick cartilage is not very common in OSD. However, cartilage thickness may reflect the status of OSD.

Overuse injuries are prevalent in children's competitive football: a prospective study using the OSTRC Overuse Injury Questionnaire

OBJECTIVES

To investigate the prevalence and burden of overuse injuries in children's football as well as player characteristics and their association with overuse injury risk.

METHODS

This investigation is based on the control arm (10 clubs) of a randomised controlled trial investigating prevention of injuries in youth football. We conducted a prospective 20-week follow-up study on overuse injuries among Finnish football players (n=733, aged 9-14 years). Each week, we sent a text message to players' parents to ask if the player had sustained any injury during the past week. Players with overuse problem were interviewed over the phone using an overuse injury questionnaire. The main outcome measures were prevalence of all overuse injuries and substantial overuse injuries (those leading to moderate or severe reductions in participation or performance) and injury severity.

RESULTS

The average response rate was 95%. In total, 343 players (46.8%) reported an overuse problem while in the study. The average weekly prevalence of all overuse problems and substantial overuse problems was 12.8% and 6.0%, respectively. Injuries affecting the knee had the highest weekly prevalence (5.7% and 2.4% for all and substantial knee problems, respectively). Girls had a higher likelihood of knee problems (OR 2.70; 95% CI 1.69 to 4.17), whereas boys had a higher likelihood of heel problems (OR 2.82; 95% CI 1.07 to 7.44). The likelihood of reporting an overuse problem increased with age (OR 1.21; 95% CI 1.00 to 1.47).

CONCLUSION

Overuse injuries are prevalent in children's competitive football. Knee overuse injuries represent the greatest burden on participation and performance.

TRIAL REGISTRATION NUMBER

ISRCTN14046021.

Association between trunk pain and lower extremity pain among youth soccer players: a cross-sectional study

Background

Soccer is a high-intensity sport with a high injury rate. Among youth soccer players, lower extremity pain is a major problem that could be associated with trunk function. This study investigated the association between lower extremity pain and trunk pain among youth soccer players.

Methods

A cross-sectional study involving youth soccer players participating in the Miyagi Amateur Sports Association was conducted using a self-reported questionnaire. A multiple logistic regression analysis was used to examine the association between trunk pain and lower extremity pain. Covariates were sex, age, body mass index, height increase, number of days of training per week, practice time per day on weekdays or weekends, competition levels, frequency of participation in games, and previous injuries.

Results

The final study population comprised 1139 youth soccer players (age, 6-15 years; male, 94.2%). Lower extremity pain with concomitant trunk pain occurred in 61.8% (42/68). Trunk pain was significantly associated with lower extremity pain (adjusted odds ratio [OR], 6.82; 95% confidence interval [CI], 3.99-11.67). Back pain and hip pain were significantly associated with knee pain (adjusted OR [95% CI]: 7.63 [3.70-15.76] and 3.84 [1.89-7.83], respectively), ankle pain (adjusted OR [95% CI]: 9.03 [4.42-18.44] and 5.43 [2.77-10.62], respectively), and both knee and ankle pain (adjusted OR [95% CI]: 13.67 [6.01-31.09] and 5.98 [2.56-13.97], respectively).

Conclusions

Trunk pain was associated with lower extremity pain among youth soccer players. Clinicians and coaches should consider comorbidities while treating those players.

The 'Sequence of Prevention' for musculoskeletal injuries among recreational basketballers: a systematic review of the scientific literature

OBJECTIVE

Currently, there is no overview of the incidence and (basketball-specific) risk factors of musculoskeletal injuries among recreational basketball players, nor any insight into the effect of preventive measures on the incidence of basketball injuries. This study aimed to gather systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures for musculoskeletal injuries among recreational basketball players.

METHODS

Highly sensitive search strategies were built based on three groups of keywords (and related search terms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost.

RESULTS

The incidence of musculoskeletal injuries among recreational basketball players ranged from 0.0047 injuries per 1,000 athlete-exposures (AE) for dental injuries to 10.1 injuries per 1000 AE for overall injuries during match play. Significant risk factors for injuries were defending, postural sway, high vertical ground reaction force during jumping and weight >75 kg. All prevention studies have shown to have a significant effect on reducing the risk of injury ranging from an odds ratio (95% confidence interval (CI)) of 0.175 (0.049-0.626) for training injuries and a relative risk (95% CI) of 0.83 (0.57-1.19) achieved with FIFA 11+ prevention exercises and sport-specific balance training, relatively.

CONCLUSION

In order to gain insight in the aetiology of basketball-specific injuries and consequently facilitate the development of preventive strategies, more high quality basketball-specific and injury-specific studies among recreational basketball players are needed.

Risk Factors for Lower Extremity Overuse Injuries in Female Youth Soccer Players

Background:

Youth soccer injuries are common and of increasing concern, with sport specialization occurring at younger ages. Limited research is available regarding overuse injuries and risk factors in young female athletes.

Purpose:

To identify the number and rate of overuse injuries in female soccer players (ages 12-15 years), describe the anatomic location and type of injury, and evaluate contributing risk factors.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 351 female youth soccer players, ages 12 to 15 years, from Washington State were evaluated from 2008 to 2012. Players with lower extremity overuse injuries were identified through weekly emails and were interviewed by telephone to obtain data on injury type and body region. We evaluated the association between overuse injuries and preseason risk factors, including joint hypermobility, hip and knee muscle strength, and jump biomechanics, using Poisson regression to estimate relative risk (RR) and 95% CIs.

Results:

The incidence rate for first-time lower extremity overuse injuries was 1.7 per 1000 athlete-exposure hours (AEH; 95% CI, 1.4-2.2), and that for repeat injuries was 3.4 per 1000 AEH (95% CI, 2.1-5.6). Knee injuries accounted for 47% of overuse injuries. Increased valgus was associated with a 3.2-fold increased risk (95% CI, 1.52-6.71) for knee injury. A 1–standard deviation (SD) increase in hamstring strength was associated with a 35% decreased risk (RR, 0.65; 95% CI, 0.46-0.91) for overuse knee injuries, and a 1-SD increase in quadriceps strength was associated with a 30% decreased risk (RR, 0.70; 95% CI, 0.50-0.98). A 1-SD increase in hip flexor strength was associated with a 28% decreased risk (RR, 0.72; 95% CI, 0.51-1.00) for overuse knee injuries, and a 1-SD increase in external rotation strength was associated with a 35% decreased risk (RR, 0.65; 95% CI, 0.46-0.91). Playing on more than 1 soccer team was associated with a 2.5-fold increased risk (95% CI, 1.08-5.35) for overuse knee injuries, and participating in other physical activities was associated with a 61% decreased risk (odds ratio, 0.39; 95% CI, 0.15-0.81).

Conclusion:

In this study, lower extremity overuse injuries in female youth soccer players affected primarily the knee. Lower knee separation distance, decreased lower extremity strength, and playing on more than 1 soccer team increased injury risk.

Bilateral Anterior Knee Pain in a High School Cross-Country Runner: An Atypical Etiology

Anterior knee pain is a common complaint found in distance runners, and can be the end result of a variety of benign processes. A 17-year-old female cross-country runner presented to a sports medicine clinic with insidious onset of bilateral patellofemoral pain (PFP). In the workup of the significant quadriceps weakness discovered on her initial examination, a principal contributing cause of her PFP, she was found to have a form of spinal muscular atrophy, an uncommon neurodegenerative disease that typically requires multidisciplinary medical care. Her case provides a good example for clinicians to consider, at times, an in-depth assessment of the root causes of benign conditions.

Screening for musculoskeletal problems in Japanese schoolchildren: a cross-sectional study nested in a cohort

OBJECTIVES

To clarify the frequency of musculoskeletal problems in public elementary and junior high school children and to determine the advantages and problems of musculoskeletal examinations.

STUDY DESIGN

School-based cross-sectional study nested in a cohort.

METHODS

We examined 41,376 public elementary and junior high school children (aged 6-15 years) in Miyazaki, Japan, from 2008 to 2014. Participation was voluntary. Participants received an in-school primary musculoskeletal examination (clinical examination with check items and a questionnaire) and a secondary examination at an orthopaedic outpatient clinic as indicated. Estimated prevalence rates for musculoskeletal problems were calculated from the results of both examinations.

RESULTS

The total estimated prevalence of musculoskeletal problems was 8.6%. Prevalence by school grade ranged from 3.2% to 13.7%. Estimated prevalence rates increased as grade increased and were higher in junior high school students than in elementary school students. The secondary examination identified musculoskeletal problems on the back (65.4%), knee (8.1%), ankle or feet (7.3%) and elbow (5.4%). Of those referred for a secondary examination, 44.4% had not reported musculoskeletal complaints on the initial questionnaire. Overall, 69.8% of problems diagnosed in the secondary examination were previously undiagnosed.

CONCLUSIONS

School-based musculoskeletal examination enables early detection of abnormal growth and disorders of the locomotive organs and is expected to support children's musculoskeletal growth and development. We recommend musculoskeletal examinations as part of school check-ups in Japan. Our findings suggest musculoskeletal examinations should be conducted for students in higher elementary school grades and for all junior high school students. Evaluation should include both direct clinical examination and questionnaires.