Patellofemoral pain syndrome in children and adolescents: A cross-sectional study.

OBJECTIVES: To assess the prevalence and associated factors of Patellofemoral Pain Syndrome (PFPS) in children and adolescents. METHOD: A population-based cross-sectional study was conducted with children and adolescents aged 10 to 18 years, who presented a history of peripatellar and/or retropatellar pain, attending elementary or high school in urban public schools in Natal, Brazil. The sample size was calculated based on a minimum outcome prevalence of 22%. RESULTS: A prevalence of 24.7% of PFPS was found. There was a positive association of PFPS with active students (p < 0.01; PR: 2.5; CI: 1.4-4.5), low functional capacity (p < 0.01; PR: 8.0; CI: 5.0-12.8), and those classified as pubertal (p < 0.03; PR: 1.8; CI: 1.0-3.2). CONCLUSION: There was a considerable prevalence of PFPS in children and adolescents, as well as an association between the level of sexual maturation and adjustable determinants, such as the level of physical activity and low functional capacity in this group.

Patellofemoral pain in general practice: the incidence and management.

BACKGROUND: Patellofemoral pain (PFP) is a nontraumatic knee problem primarily observed in physically active adolescents. The objective of this study was to determine the incidence and management of PFP in children and adolescents in general practice. METHODS: A retrospective cohort study was conducted using a regional primary care database containing full electronic health records of over 300,000 patients. Patients with a new PFP diagnosis between the years 2013 and 2019 were extracted using a search algorithm based on International Classification of Primary Health Care coding and search terms in free text. Data on the management of PFP were manually checked and analysed. In addition, a sub-analysis for chronic and nonchronic PFP patients was performed. RESULTS: The mean incidence of PFP over the study period was 3.4 (95% CI 3.2-3.6) per 1,000 person years in the age group of 7-24 years. Girls had a higher incidence rate (4.6 [95% CI 4.3-5.0]) compared to boys (2.3 [95% CI 2.1-2.5]). Peak incidence was at age 13 years for both sexes. The most commonly applied management strategy was advice (55.1%), followed by referral to physiotherapy (28.2%), analgesics prescription (10.4%), and referral to the orthopaedic surgeon (8.9%). No differences were found in age, sex, and treatment between chronic and nonchronic PFP patients. CONCLUSIONS: The average Dutch general practitioner sees approximately 1.4 new child or adolescent with PFP per year. Overall management strategies were in concordance with current Dutch general practice guideline on nontraumatic knee problems. More insight should be gained in the population with chronic complaints.

Patellofemoral Pain Syndrome Is Associated With Chronic Disease and Allergies in 60 997 Distance Runner Race Entrants: SAFER XXX Study.

OBJECTIVE: Patellofemoral pain syndrome (PFPS) is a common running-related injury. Independent risk factors associated with PFPS have not been described in a large cohort of distance runners. DESIGN: Descriptive, cross-sectional study. SETTING: 21.1 and 56 km Two Oceans Marathon races (2012-2015). PARTICIPANTS: 60 997 race entrants. ASSESSMENT OF RISK FACTORS: Participants completed a compulsory prerace medical screening questionnaire (history of PFPS in the past 12 months, n = 362; no injury history, n = 60 635). Selected risk factors associated with a history of PFPS were explored using univariate & multivariate analyses: demographics, training/running variables, history of chronic diseases (composite chronic disease score), and any allergy. MAIN OUTCOME MEASURES: Prevalence ratios (PRs, 95% confidence intervals). RESULTS: Risk factors associated with PFPS (univariate analysis) were increased years of recreational running (PR = 1.09; P = 0.0107), older age (>50 years), and chronic diseases (PR > 2): gastrointestinal disease (PR = 5.06; P < 0.0001), cardiovascular disease (CVD) (PR = 3.28; P < 0.0001), nervous system/psychiatric disease (PR = 3.04; P < 0.0001), cancer (PR = 2.83; P = 0.0005), risk factors for CVD (PR = 2.42; P < 0.0001), symptoms of CVD (PR = 2.38; P = 0.0397), and respiratory disease (PR = 2.00; P < 0.0001). Independent risk factors (multivariate analysis) associated with PFPS (adjusted for age, sex, and race distance) were a higher chronic disease composite score (PR = 2.68 increased risk for every 2 additional chronic diseases; P < 0.0001) and a history of allergies (PR = 2.33; P < 0.0001). CONCLUSIONS: Novel independent risk factors associated with PFPS in distance runners are a history of multiple chronic diseases and a history of allergies. Identification of chronic diseases and allergies should be considered as part of the clinical assessment of a runner presenting with a history of PFPS.

What is the incidence of subsequent adjacent joint injury after patellofemoral pain?

OBJECTIVE: To investigate the incidence of subsequent lumbar spine, hip, and ankle-foot injuries after a diagnosis of patellofemoral pain. DESIGN: Retrospective cohort study. SETTING: Military Health System. PARTICIPANTS: Individuals (n = 92,319) ages 17-60 diagnosed with patellofemoral pain between 2010-2011. INTERVENTIONS: Therapeutic exercise. MAIN OUTCOME MEASURES: Frequency of adjacent joint injuries in the 2-year period after initial patellofemoral pain injury, and hazard ratios (HR) with 95% confidence interval (CI) and Kaplan-Meier survival curves for risk of adjacent joint injury based on receiving therapeutic exercise for the initial injury. RESULTS: After initial patellofemoral pain diagnosis, 42,983 (46.6%) individuals sought care for an adjacent joint injury. Of these, 19,587 (21.2%) were subsequently diagnosed with a lumbar injury, 2837 (3.1%) a hip injury, and 10,166 (11.0%) an ankle-foot injury. One in five (19.5%; n = 17,966) received therapeutic exercise which reduced the risk of having a subsequent lumbar (HR = 0.78, 95% CI 0.76-0.81), hip (HR = 0.93, 95% CI 0.87-0.98) or ankle-foot (HR = 0.86, 95% CI 0.83-0.90) injury. CONCLUSION: The results suggest that a high number of individuals with patellofemoral pain will sustain an adjacent joint injury within 2 years although causal relationships cannot be determined. Receiving therapeutic exercise for the initial knee injury reduced the risk of sustaining an adjacent joint injury. This study helps provide normative data for subsequent injury rates in this population and guide development of future studies designed to understand causal factors.

Exploring overweight and obesity beyond body mass index: A body composition analysis in people with and without patellofemoral pain.

BACKGROUND: We compared body mass index (BMI), body fat, and skeletal muscle mass between (1) a mixed-sex nonathletic cohort of people with patellofemoral pain (PFP) and pain-free people, and (2) a nonathletic cohort of people with PFP and pain-free people subgrouped by sex (i.e., men and women with PFP vs. pain-free men and women). METHODS: This cross-sectional study included 114 people with PFP (71 women, 43 men) and 54 pain-free controls (32 women, 22 men). All participants attended a single testing session to assess body composition measures, which included BMI, percentage of body fat (%BFBioimpedance), and skeletal muscle mass (both assessed by bioelectrical impedance analysis), and percentage of body fat (%BFSkinfold) (assessed by skinfold caliper analysis). A one-way univariate analysis of covariance (age and physical activity levels as covariates) was used to compare body composition measures between groups (i.e., PFP vs. pain-free group; women with PFP vs. pain-free women; men with PFP vs. pain-free men). RESULTS: Women with PFP presented significantly higher BMI, %BFBioimpedance, and %BFSkinfold, and lower skeletal muscle mass compared to pain-free women (p ≤ 0.04; effect size : ‒0.47 to 0.85). Men with PFP and men and women combined had no differences in BMI, %BFBioimpedance, %BFSkinfold, and skeletal muscle mass compared to their respective pain-free groups (p > 0.05). CONCLUSION: Our findings indicate that BMI and body composition measures should be considered as part of the evaluation and management of people with PFP, especially in women, who have demonstrated higher BMI and body fat and lower skeletal muscle mass compared to pain-free controls. Future studies should not assess body composition measures in a mixed-sex population without distinguishing men participants from women participants.

Factors associated with patellofemoral pain in recreational road cyclists: A cross-sectional study in 59953 cyclists - SAFER XXXIII.

OBJECTIVE: Patellofemoral pain (PFP) is a common cycling-related injury, and independent factors need to be identified to enable effective injury prevention strategies. We aim to determine factors associated with PFP in cyclists entering mass community-based events. DESIGN: Cross-sectional study. SETTING: 2016-2020 Cape Town Cycle Tour. PARTICIPANTS: Consenting race entrants. MAIN OUTCOME MEASURES: 62758 consenting race entrants completed a pre-race medical questionnaire, and 323 reported PFP. Selected factors associated with PFP (demographics, cycling experience and training, chronic disease history) were explored using multivariate analyses. RESULTS: Prevalence ratio (PR) of PFP was similar for sex and age groups. Independent factors associated with PFP (adjusted for sex and age) were history of chronic disease [Composite Chronic Disease Score (0-10)(PR = 2.0, p < 0.0001) and any allergies (PR = 2.0, p < 0.0001)]. CONCLUSION: A history of chronic diseases and allergies is associated with PFP in cyclists. Practical clinical recommendations are: 1) that prevention programs for PFP be considered when cycling is prescribed as a physical activity intervention for patients with chronic disease, and 2) that older cyclists presenting with PFP be assessed for the presence of risk factors or existing chronic disease.

Epidemiology of gradual-onset knee injuries in team ball-sports: A systematic review with meta-analysis of prevalence, incidence, and burden by sex, sport, age, and participation level.

OBJECTIVES: To systematically evaluate the literature and estimate the prevalence, incidence, and burden of gradual-onset knee injuries in team ball-sports. DESIGN: Systematic review with meta-analysis. METHODS: Six databases (MEDLINE, EMBASE, Web of Science, CINAHL, SPORTDiscus, SCOPUS) were searched from inception to June 2021. Cohort studies of team ball-sports reporting the number of gradual-onset knee injuries were included. Study quality was assessed using a modified Newcastle-Ottawa scale. Studies were pooled using a Freeman-Tukey Double arcsine transformation (prevalence) and a Poisson random effects regression model (incidence, burden). RESULTS: Forty-nine studies that captured gradual-onset knee injuries (unclassified, patellofemoral pain, tendinopathies, and iliotibial band friction syndrome) across 15 team ball-sports were included. For unclassified gradual-onset knee injuries, prevalence was 4 % (95 % Confidence Interval (CI) 2 % to 7 %, I2 = 96 %), incidence was 0.32 per 1000 player-hours (95 % CI 0.25 to 0.43, I2 = 88 %), and burden was 3.24 days lost per 1000 player-hours (95 % CI 1.95 to 5.37, I2 = 99 %). For patellofemoral pain, prevalence was 6 % (95 % CI 1 % to 13 %, I2 = 93 %), and incidence was 0.07 per 1000 player-hours (95 % CI 0.04 to 0.12, I2 = 67 %). For tendinopathies, prevalence was 1 % (95 % CI 0 % to 2 %, I2 = 68 %), incidence was 0.07 per 1000 player-hours (95 % CI 0.04 to 0.11, I2 = 76 %), and burden was 2.14 days lost per 1000 player-hours (95 % CI 1.23 to 3.71, I2 = 92 %). CONCLUSIONS: Estimates of prevalence, incidence and burden generated from this systematic review quantify the extent of gradual-onset knee injuries in team ball-sports. Further research is required to assess whether age, sport, and participation level are predictors of gradual-onset knee injuries.

Patellofemoral Pain Syndrome Risk Associated with Squats: A Systematic Review.

Patellofemoral pain syndrome (PFPS) is highly prevalent; it can cause severe pain and evolve into progressive functional loss, leading to difficulties performing daily tasks such as climbing and descending stairs and squatting. This systematic review aimed to find evidence, in the literature, of squat movements that can cause or worsen PFPS. This work was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and its protocol was registered in PROSPERO (CRD42019128711). From the 6570 collected records, 37 were included. From these 37 articles, 27 present a causal relationship between knee flexion and PFPS, 8 describe a relationship, considering the greater existence of muscle contractions, and one article did not describe this relationship in its results. The main limitations stem from the fact that different studies used different evaluation parameters to compare the force exerted on the patellofemoral joint. Furthermore, most studies are focused on sports populations. After analysing the included works, it was concluded that all squat exercises can cause tension overload in the knee, especially with a knee flexion between 60° and 90° degrees. The main causal/worsening factors of PFPS symptoms are the knee translocation forward the toes (on the same body side) when flexing the knee, and the muscle imbalance between the thigh muscles.

The prevalence of patellofemoral pain in the Rugby League World Cup (RLWC) 2021 spectators: A protocol of a cross-sectional study.

Patellofemoral pain (PFP) can cause significant pain leading to limitations in societal participation and physical activity. PFP is usually associated with athletes undergoing intensive physical training, or military recruits; but recent evidence shows that PFP is common in the general population. The relationship of PFP with physical activity is not entirely clear. Our aim is to provide a better estimate of the general population prevalence of PFP and to relate this to the level of physical activity, and demographic characteristics. The Survey instrument for Natural history, Aetiology and Prevalence of Patellofemoral pain Studies (SNAPPS) was developed as a PFP screening tool to be used in the community. The electronic version of the SNAPPS (eSNAPPS) has recently been validated and was used to survey attendees at mass-participation running events. We will use an electronic survey to collect data from a sample of 1100 Rugby League World Cup spectators. The survey will have four sections: i) general and demographic; ii) knee pain (eSNAPPS); iii) level of physical activity; and iv) quality of life in relation to knee pain. The primary analytic approach will be descriptive of PFP prevalence. Secondary analyses will explore the relationships of the presence of PFP and the other variables. We will disseminate this work by publication of peer-reviewed papers in scientific journals, presentations at scientific conferences, and on the dedicated SNAPPS website https://www.snappspfp.com/.

Prevalence of Trochlear Dysplasia and Associations with Patellofemoral Pain and Instability in a Skeletally Mature Population.

BACKGROUND: Patellar instability among adolescents has an incidence of 29 to 43 per 100,000 per year. Trochlear dysplasia has been found in up to 85% of those with recurrent patellar instability. The prevalence of trochlear dysplasia in the general population has not yet been defined. The purpose of the present study was to determine the prevalence of trochlear dysplasia as defined by ultrasound in a skeletally mature population and to characterize associations of trochlear dysplasia with a history of patellofemoral instability or pain. METHODS: Skeletally mature adolescents and parents of patients (≤50 years of age) who had presented to orthopaedic clinics were prospectively enrolled from 2019 to 2020. Those presenting with knee pain, open physes, prior intra-articular fracture, total knee arthroplasty, and syndromic ligamentous laxity or neuromuscular disease were excluded. Information regarding a history of anterior knee pain, patellar instability, and/or surgery was obtained, and an abbreviated Anterior Knee Pain Scale (AKPS) was collected. An AKPS score of ≥4 was considered positive. Bilateral ultrasound of the knee was performed, and the osseous sulcus angle of the trochlea and the trochlear depth were measured. Basic descriptive statistics are reported. RESULTS: One hundred and two patients (203 knees) were studied. The mean sulcus angle was 144.1° ± 6.8°, and the mean trochlear depth was 5.5 ± 1.4 mm. High-grade trochlear dysplasia was defined as the 95th percentile and above, which was shown to be a sulcus angle of ≥154° or a trochlear depth of ≤3 mm for female patients and ≤4 mm for male patients. The prevalence of high-grade trochlear dysplasia was 5.4% based on the sulcus angle and 9.9% based on trochlear depth. Knees with high-grade trochlear dysplasia based on the sulcus angle were 11 times more likely to have had previous patellar instability (p = 0.013). CONCLUSIONS: The prevalence of high-grade trochlear dysplasia in the general population is approximately 10%, and there may be an association with patellar instability. The use of ultrasound to diagnose trochlear dysplasia may prove to be a rapid and useful tool for guiding patient education and treatment decisions. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Timing of physical therapy for individuals with patellofemoral pain and the influence on healthcare use, costs and recurrence rates: an observational study.

BACKGROUND: Early physical therapy has been shown to decrease downstream healthcare use, costs and recurrence rates in some musculoskeletal conditions, but it has not been investigated in individuals with patellofemoral pain. The purpose was to evaluate how the use and timing of physical therapy influenced downstream healthcare use, costs, and recurrence rates. METHODS: Seventy-four thousand four hundred eight individuals aged 18 to 50 diagnosed with patellofemoral pain between 2010 and 2011 in the Military Health System were categorized based on use and timing of physical therapy (first, early, or delayed). Healthcare use, costs, and recurrence rates were compared between the groups using descriptive statistics and a binary logit regression. RESULTS: The odds for receiving downstream healthcare use (i.e. imaging, prescription medications, and injections) were lowest in those who saw a physical therapist as the initial contact provider (physical therapy first), and highest in those who had delayed physical therapy (31-90 days after patellofemoral pain diagnosis). Knee-related costs for those receiving physical therapy were lowest in the physical therapy first group ($1,136, 95% CI $1,056, $1,217) and highest in the delayed physical therapy group ($2,283, 95% CI $2,192, $2,374). Recurrence rates were lowest in the physical therapy first group (AOR = 0.55, 95% CI 0.37, 0.79) and highest in the delayed physical therapy group (AOR = 1.78, 95% CI 1.36, 2.33). CONCLUSIONS: For individuals with patellofemoral pain using physical therapy, timing is likely to influence outcomes. Healthcare use and costs and the odds of having a recurrence of knee pain were lower for patients who had physical therapy first or early compared to having delayed physical therapy.

Validation and utilisation of a digital version of the survey instrument for natural history, Aetiology and Prevalence of Patellofemoral pain studies (eSNAPPS).

OBJECTIVE: This study validated the newly adapted electronic SNAPPS (eSNAPPS) against the original paper SNAPPS. Subsequently, the study estimated the prevalence of PFP in running participants and spectators attending three mass-participant running events in the United Kingdom by using the eSNAPPS tool. DESIGN: This study had two parts. Firstly, a validation of the original paper version of the SNAPPS tool. Secondly, if validation was achieved, eSNAPPS was used in a prevalence study. PARTICIPANTS: A convenience sample of running participants and spectators aged 18-40 years attending the mass participation running events. MAIN OUTCOME MEASURE: The 12-month prevalence of PFP. RESULTS: eSNAPPS was valid in identifying those with PFP (ICC 0.99 for Overall agreement, p < 0.0001). In the prevalence study, a total of 1080 running participants and spectators completed the eSNAPPS. The overall prevalence of PFP was 17.4% (95%CI: 15.2%, 19.8%); 20.5% of males (16.5, 24.9) and 15.7% of females (13.1, 18.7) had PFP. Prevalence was 17.4% (15.2, 19.8) in spectators and 16.7% in running participants (14.5, 19.0). CONCLUSION: The overall PFP prevalence in this study was slightly smaller than those previously reported in the literature. Findings also show that there were similar prevalence estimates in spectators and running participants.

Sex and Mental Health Disorder Differences Among Military Service Members With Patellofemoral Syndrome.

BACKGROUND: Mental health disorders are associated with persistent knee pain, but the association between these conditions has had little investigation in the military. The purpose of this study was to identify rates of mental health disorders in patients with patellofemoral pain (PFP) and determine differences by sex and whether mental health copresence influences outcomes. METHODS: Eligible patients with a new PFP diagnosis were categorized according to sex and presence of mental health disorders. Outcomes included odds of mental health disorder before/after initial PFP diagnosis based on sex, and knee-related health care use between patients with/without mental health disorders. RESULTS: In 81,832 individuals with PFP (71.1% men; mean age 33; 91.5% active duty), copresence of any mental health disorders was common (18% men; 28% women). Women had more depression and anxiety; men had more post-traumatic stress disorder and substance abuse disorders. Concurrent mental health disorders after initial PFP diagnosis resulted in higher medical costs and odds of a recurrence (OR 1.24; 95% CI 1.20, 1.28; P < .001). CONCLUSION: Mental health disorders are common in military service members seeking care for patellofemoral pain. Differences in prevalence vary by sex, and presence of mental health disorders adversely affected long-term health care outcomes.

Gender-Specific Risk Factor Profiles for Patellofemoral Pain.

OBJECTIVE: To determine the association between selected biomechanical variables and risk of patellofemoral pain (PFP) in males and females. DESIGN: Prospective cohort. SETTING: US Service Academies. PARTICIPANTS: Four thousand five hundred forty-three cadets (1727 females and 2816 males). ASSESSMENT OF RISK FACTORS: Three-dimensional biomechanics during a jump-landing task, lower-extremity strength, Q-angle, and navicular drop. MAIN OUTCOME MEASURES: Cadets were monitored for diagnosis of PFP during their enrollment in a service academy. Three-dimensional hip and knee kinematic data were determined at initial contact (IC) and at 50% of the stance phase of the jump-landing task. Logistic regression analyses were performed for each risk factor variable in males and females (P < 0.05). RESULTS: Less than 10 degrees of hip abduction at IC [odds ratio (OR) = 1.86, P = 0.03] and greater than 10 degrees of knee internal rotation at 50% of the stance phase (OR = 1.71, P = 0.02) increased the risk of PFP in females. Greater than 20 degrees of knee flexion at IC (OR = 0.47, P < 0.01) and between 0 and 5 degrees of hip external rotation at 50% of the stance phase (OR = 0.52, P = 0.04) decreased the risk of PFP in males. No other variables were associated with risk of developing PFP (P > 0.05). CONCLUSIONS: The results suggest males and females have differing kinematic risk factor profiles for the development of PFP. CLINICAL RELEVANCE: To most effectively reduce the risk of developing PFP, the risk factor variables specific to males (decreased knee flexion and increased hip external rotation) and females (decreased hip abduction and increased knee internal rotation) should be addressed in injury prevention programs.

Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review.

PURPOSE: This systematic review aimed to evaluate the variability of patellofemoral (PF) alignment and trochlear morphology in osteoarthritic knees. METHODS: PF alignment of the knee was defined by the following parameters: the sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle-trochlear groove distance (TT-TG). The electronic databases MEDLINE and EMBASE were searched from database inception to the search date (February 19, 2019) and were screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of osteoarthritic knees in patients over 40 years old were included. Data were extracted and methodological quality was assessed using a 14-item checklist. RESULTS: A total of 8 studies met the inclusion criteria. The studies reported mean values ± SD between 120° and 141.1° ± 7.7 for the SA; 5.8 mm ± 1.4 for the FTD; between - 0.1° ± 3.3 and 10.3° ± 5.7 for the PTA; between 5.8° ± 5.4 and 17° for the LPFA; between 23.2° ± 5.0 and 27.1° ± 4.4 for the LFTI; and 5.8 mm ± 5.4 for the TT-TG. CONCLUSION: PF alignment in the osteoarthritic knee is more variable than expected. This finding should encourage surgeons to consider the individual preoperative PF alignment more precisely with the aim of reducing anterior knee pain (AKP) after TKA. 3D-CT imaging might be of great value to analyse the PF alignment in an appropriate way. LEVEL OF EVIDENCE: Level III.

Can young dancers skip/recover from patellofemoral pain? A two-year follow-up.

Aiming to follow the prevalence of patellofemoral pain (PFP) among young dancers over 2-years, and to assess the prevalence of re-injured/recovered dancers; 67 dancers (aged 12.8 ± 0.5) were screened for PFP at baseline, 65 dancers at 1st follow-up and 51 dancers at 2nd follow-up. All dancers (46) that took part in all the 3 screenings had at least one episode of PFP along the screenings. No dancers recovered in the 1st follow-up, yet 40.5% of the dancers with PFP at the 1st follow-up recovered in the 2nd follow-up. Along the 3 screenings, 23.9%, 34.8%, and 41.3% of the dancers had 1,2 or 3 PFP episodes, respectively. None of the dancers skipped PFP along the 3 screenings. A high prevalence of dancers had sustained PFP along the 2 follow-ups, with low recovery rate. Dancers and teachers should be alert to the need for devising modifications of training and injury prevention strategies from young age.

Unilateral and bilateral patellofemoral pain in young female dancers: Associated factors.

Aiming to evaluate the prevalence of unilateral/bilateral patellofemoral pain (PFP) among young dancers, and to investigate whether different factors are associated with PFP in young dancers, 132 dancers aged 12-14 years were assessed for PFP. Anthropometric parameters, proprioception ability, dynamic postural balance (DPB), and muscle strength were measured. PFP was found in 64.1% of the dancers. No significant differences in the prevalence of dancers with no, unilateral, or bilateral PFP at different ages were found. Significant age effects were found for anthropometric and developmental measurements, and for intensity of training. PFP effect was found for DPB asymmetry, ankle proprioception, and leg-length %height. A higher hip abductor/adductor ratio was associated with PFP in 14-year-old dancers. Binomial logistic regression showed that increased number of hours per day (h/day) and decreased number of hours per week (h/week), low proprioception scores, greater leg length as %height, and more anterior DPB asymmetry were significant predictors of PFP. In conclusion: unilateral/bilateral PFP is common among young dancers. Body morphology, reduced ankle proprioception ability, DPB asymmetry, and increased h/day of practice are associated with PFP. Dance teachers should start monitoring the impact of training and implement injury modification/prevention strategies when their students are at a young age.

Common Medical Concerns of the Female Athlete.

Women are increasingly participating in more and more sporting activities. For years, women athletes have been treated as the "female" equivalent of male athletes, with similar medical approaches but this is changing. The concept that women are unique in their "athletic arena" is further underscored with emerging scientific evidence--from the physiologic details not visible to the eye, to the more overt biomechanical and anatomic differences. We review a handful of conditions active women potentially may encounter: pregnancy, the female athlete triad, patellofemoral pain, potential injuries to the anterior cruciate ligament, and anemia.

Comparison of three different approaches for anterior knee pain after tibia intramedullary nailing.

PURPOSE: The aim of this study was to compare anterior knee pain and functional outcomes in patients who underwent intramedullary tibial nailing using transpatellar, medial parapatellar or suprapatellar nail entry methods. METHODS: We retrospectively reviewed patients who underwent tibial fracture repair in our clinic between January 2010 and March 2017. After applying the exclusion criteria, 58 patients were included in the study. Patients were divided into 3 groups based on the nailing approach: medial parapatellar, transpatellar or suprapatellar. Age, body mass index, follow-up duration, Kujala Score, Lysholm Knee Score, anterior knee pain, length of hospitalization and surgical duration were assessed. RESULTS: Of the 58 patients studied, 21 underwent a transpatellar (TP) approach, 16 a medial parapatellar (MP) approach, and 21 a suprapatellar (SP) approach. The mean Kujala Score of patients who had the TP approach was 80 ± 7.15 (72-93) and the average Lysholm Knee Score was 80.23 ± 8.74 (70-95). There was no statistically significant difference between Kujala Scores (p = 0.38) or Lysholm Knee Scores (p 0.06) among the groups; similarly, no statistically significant difference was found among the three groups in terms of anterior knee pain, length of hospitalization or surgical duration (p > 0.05). CONCLUSION: The suprapatellar tibia nailing method is as safe and reliable as transpatellar and medial parapatellar methods in terms of effect on postoperative anterior knee pain and functional outcomes. LEVEL OF EVIDENCE: Level 3 case-control study.

Prevalence of patellofemoral pain and knee pain in the general population of Chinese young adults: a community-based questionnaire survey.

BACKGROUND: Previous studies that have described the prevalence of patellofemoral pain (PFP) have been limited to samples of military personnel or sporting populations, and convincing data in the general Chinese population are lacking. The present study defined the prevalence of PFP and knee pain in the general population of Chinese young adults and evaluated whether gender, age, or body mass index (BMI) were associated with PFP. METHODS: An anonymous online questionnaire survey was open to the general public in China. A self-report questionnaire was used to specifically identify PFP. The population aged 18-40 years was enrolled in the study and completed the questionnaire. The prevalence of PFP and knee pain in the overall sample and in subgroups stratified by sex, age, and BMI was estimated. Logistic regression analysis was conducted to determine if there was a significant association between PFP and sex, age, or BMI. RESULTS: A total of 1153 participants were enrolled in the study. The prevalence of PFP in the overall sample and among the male and female participants was 20.7, 20.3, and 21.2%, respectively. The prevalence of the knee pain in the overall sample and among the male and female participants was 35.6, 38.2, and 33.7%, respectively. The prevalence of PFP in the subgroups stratified by age and BMI did not differ significantly between the groups. Gender, age, and BMI did not have significant associations with the prevalence of PFP. CONCLUSION: PFP is common in the general Chinese population. Clinicians should direct more attention toward the early diagnosis of and interventions for PFP.