Evaluation and management of knee pain in young athletes: overuse injuries of the knee

Gymnastics Medicine: A New Subspecialty in Sports Medicine

ABSTRACT

Despite popularity of gymnastics, there is no independent medical organization/subspecialty group to investigate injuries and prevention, and to make the sport safer for all. Thus, a new sports medicine subspecialty is proposed: Gymnastics Medicine. Gymnastics injury rates are higher compared to other sports. Common injuries occurring in gymnastics include gymnast wrist, grip lock, osteochondritis dissecans of the elbow, knee, and ankle, shoulder overuse injuries, mechanical low back pain, spondylolysis, pelvic apophysitis, anterior cruciate ligament tears, ankle instability/ankle sprains, symptomatic accessory navicular, os trigonum/posterior ankle impingement, and calcaneal apophysitis. Gymnastics Medicine will help medical clinicians understand injury patterns, return to play protocols, nutritional needs, and the mental aspects of gymnastics. Gymnastics Medicine is a needed subspecialty. There are many medical subspecialties involved with the care of gymnasts who would benefit from a concentrated field, and this field allows those clinicians to collaborate, enhance research, and most importantly, improve the safety and health of athletes in gymnastics.

Knee Effusion-Synovitis Is Not Associated With Self-Reported Knee Pain in Division I Female Athletes

BACKGROUND

Recent research indicates a potential link between effusion-synovitis and knee pain in athletes. This study investigates the association of knee effusion-synovitis with self-reported knee pain in elite female athletes, leveraging ultrasound imaging for effusion-synovitis assessment.

HYPOTHESIS

Presence of knee effusion-synovitis is associated with increased self-reported knee pain in Division I female athletes.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 53 NCAA Division I female athletes underwent bilateral knee ultrasound to identify effusion-synovitis. The Knee Injury and Osteoarthritis Outcome Survey (KOOS) Pain subscale assessed knee pain. A 1-way analysis of variance compared KOOS pain, symptoms, activities during daily living (ADL), and quality of life (QoL) scores across groups with no, unilateral, and bilateral effusion-synovitis.

RESULTS

Among the athletes, 49.1% showed no effusion-synovitis, 26.4% had unilateral, and 24.5% had bilateral effusion-synovitis. There were no differences in self-reported pain scores (F = 0.027; P = 0.97), ADL (F = 0.256; P = 0.78), or QoL (F = 0.120; P = 0.88) between any groups. In addition, the frequency of effusion-synovitis was as follows: for the right limb, Grade 0 = 35 (66%), Grade 1 = 15 (28%), Grade 2 = 1 (2%), and Grade 3 = 2 (4%); for the left limb, Grade 0 = 31 (58%), Grade 1 = 19 (36%), Grade 2 = 3 (6%), and Grade 3 = 0 (0%).

CONCLUSION

The presence of effusion-synovitis, irrespective of being unilateral or bilateral, was not associated with self-reported knee pain in elite female athletes. This suggests that lower grades of effusion-synovitis may not significantly impact knee pain.

CLINICAL RELEVANCE

The findings of this study challenge existing assumptions about the impact of effusion-synovitis on knee pain in athletes, contributing to the nuanced understanding of knee joint health in sports medicine.

Prevalence and associated factors of non-traumatic knee pain in high school volleyball players: a cross-sectional study

OBJECTIVES

This study aimed to determine the prevalence of knee pain among high school volleyball attackers, identify associated factors, and explore the relationship between knee pain and lower back pain (LBP).

METHODS

A cross-sectional study involving 82 high school volleyball attackers (15-17 years) used questionnaires, interviews, and field-based assessments to collect data on demographics, volleyball-specific factors, flexibility, and jumping ability. Logistic regression analysis was used to identify factors associated with knee pain.

RESULTS

The prevalence of knee pain was 19.5%. Factors significantly associated with knee pain were a history of LBP (OR, 4.64; 95% CI, 1.28 to 16.8; p = 0.019) and flexibility determined by the absolute difference in heel-buttock distance (OR, 1.37; 95% CI, 1.02 to 1.83; p = 0.037). Participants with knee pain had more volleyball experience and a higher proportion of players who competed as starters in the previous year. Both groups reported approximately 18 hours of practice per week during the school year and around 27 hours during school holidays, with no significant difference observed.

CONCLUSION

Factors associated with knee pain include a history of LBP and reduced flexibility on the heel-buttock distance test. The study highlights the need for a comprehensive approach, considering the coexistence of LBP and focusing on improving anterior thigh flexibility.

Postoperative pain control for shoulder arthroplasty

Since its inception in 1893, shoulder arthroplasty has become an increasingly common surgical procedure. Between 1998 and 2008, shoulder arthroplasty procedures increased by nearly 28,000 cases per year in the United States alone and is the fastest growing joint replacement surgery among all joint. Despite its advantages, shoulder arthroplasty is often accompanied by significant postoperative pain. Pain control continues to be a major concern in patient management, as it impacts operative costs, postoperative mobility, length of hospital stay, patient satisfaction, and overall surgical outcomes. This review aims to provide an overview of drugs such as opioids and regional anesthetics, as well as methods such as local wound infiltration, nerve block, brachial plexus infiltration, cryotherapy and multimodal approaches employed in postoperative shoulder arthroplasty pain control.

Osgood-Schlatter Disease: Ossicle Resection and Patellar Tendon Repair in a Symptomatic Adult

Chronic Osgood-Schlatter disease can cause significant knee pain and can result in severe functional deficits. For large, painful Osgood-Schlatter disease ossicles refractory to conservative management, surgical ossicle excision can provide resolution of symptoms. After diagnostic arthroscopy and intra-articular debridement, our preferred excision technique uses an open incision for direct visualization and removal of intratendinous ossicles, followed by distal patellar tendon repair and subsequent fixation with FiberTape sutures and knotless anchors to the tibial tubercle.

Evaluation of posterior tibial slope relationship with common knee pathologies in pediatric and adolescent age groups in the Turkish population

Anterior cruciate ligament rupture (ACLR), tibial eminence fracture (TEF), and Osgood-Schlatter disease (OSD) have been linked to a steep posterior tibial slope (PTS) in children and adolescents. This study aims to examine and compare these associations. 418 patients aged 8-18, 237 males and 181 females with knee pain between 2010 and 2019 were included and the patients belonged to the Turkish population. They consisted of ACLR (n = 47), TEF (n = 22), OSD (n = 51), and a control group (n = 298). The study and control groups were compared for PTS, sex, and age, with ACLR, TEF, OSD, retrospectively. The ACLR, OSD, and TEF groups had higher PTS values than the control group ( P < 0.001). There was no significant difference in ACLR-OSD, ACLR-TEF, and OSD-TEF comparisons ( P = 0.22, P = 0.99, and P = 0.99, respectively). PTS increase was linked to ACLR, TEF, and OSD in the multinomial regression analysis, ( P < 0.001). Increase in PTS was associated with ACLR, TEF, and OSD for both males and females (independently of other factors; ACLR: P < 0.001, P < 0.001, OR: 1.59, OR: 2.63, TEF: P = 0.001, P < 0.001, OR: 1.98, OR: 1.44; OSD: P = 0.001, P < 0.001, OR: 1.49, OR: 1.28 for males and females respectively). ACLR, TEF, and OSD are associated with increased PTS in the pediatric and adolescent age groups, and there are differences between these pathologies in terms of the amount of PTS increase, age, and sex. Consideration of age and gender in pediatric and adolescent patients with increased PTS may be useful in predicting pathologies associated with increased PTS. Level of evidence: III retrospective comparative study.

Development of interprofessional educational module for understanding the musculoskeletal basis of sports injury

Context

Interprofessional education (IPE) is crucial in promoting a better understanding of collaborative practices within the healthcare system. Unfortunately, healthcare professionals are still working in isolation. To address this issue, a study was conducted to develop a module-based teaching and learning activity focusing on sports injuries and to promote IPE.

Aims

The aim of the study was to develop, implement, and evaluate an IPE module.

Settings and Design

An educational mixed-method study was conducted on 25 facilitators and 108 students.

Methods Materials and Statistical Analysis

The facilitators were interviewed for an assessment of the need for the IPE module. Qualitative analysis was done on the interview data. An interprofessional team was created to develop the sports injury prevention module (SIPM). The SIPM consisting of 11 objectives was developed and validated by experts. After the implementation of SIPM students' performance was analysed with the help of pre and post-tests. The perception of students and facilitators about IP SIPM were recorded with the help of questionnaires.

Results

Need assessment data showed that the facilitators were not very familiar with the concept of IPE. There was a significant increase in students' performance with a P value ≤ 0.05 after learning with SIPM. Both facilitators and students agreed that module-based IPE increases students' attentiveness and learning.

Conclusions

For effective interprofessional educational collaboration for training students of the healthcare profession, there is a need for an interprofessional educational module. SIPM can enhance the learning of musculoskeletal anatomy and create awareness about sports injuries among students.

Multipartite patella: A review of diagnostic techniques and management of the symptomatic patient

Multipartite patella is an anatomical variant classified by the fragmentation of the main patellar body. The cause of this variant is due to failure in fusion of the patellar ossification centers. It is commonly misdiagnosed as a fracture of the patella in clinical practice, leading to unnecessary treatment measures. The aim of this review is to provide an overview of the development and classification of this variation, diagnostic imaging techniques, and assess the optimal management technique for the symptomatic patient. Multiple radiographic methods are used to identify this variant, with recent studies highlighting high sensitivity rates for nonradiative methods (ultrasound). In terms of symptomatic management, accessory fragment excision and vastus lateralis release provide the greatest alleviation of symptoms, with screw fixation being less favorable.

Sinding-Larsen-Johansson disease. Clinical features, imaging findings, conservative treatments and research perspectives: a scoping review

Objective

This review aims to consolidate existing research on the pathogenesis, clinical diagnosis, imaging outcomes, and conservative treatments of Sinding-Larsen-Johansson disease (SLJD), identifying literature gaps.

Design

Scoping Review.

Methods

A comprehensive literature search was conducted across databases including PubMed, Scopus, Medline OVID, Embase, Web of Science, and Grey literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. The quality of included studies was assessed using the Joanna Briggs Institute (JBI) checklist.

Results

The body of evidence on SLJD, primarily derived from case studies, reveals limited and often conflicting data. Key findings include: (1) SLJD commonly presents as localized knee pain in physically active adolescents, particularly males, (2) ultrasound and MRI are the most effective diagnostic tools, (3) conservative treatment, which mainly focuses on activity limitation, yields positive outcomes within two to eight months.

Conclusions

Our review shows that SLJD mainly affects physically active adolescents aged 9-17 years. The authors recommend conservative treatment, rest and/or cryotherapy, passive mobilization, muscle restraint, isometric exercise, and NSAIDs. Further cohort studies are necessary to refine the management and application of the SLJD treatment database.

Biomechanical effectiveness of controlled ankle motion boots: A systematic review and narrative synthesis

INTRODUCTION

Controlled ankle motion (CAM) boots are a below-knee orthotic device prescribed for the management of foot and ankle injuries to reduce ankle range of motion (RoM) and offload the foot and ankle whilst allowing continued ambulation during recovery. There is a lack of clarity within the current literature surrounding the biomechanical understanding and effectiveness of CAM boots.

AIMS

To summarise the biomechanical effects of CAM boot wear as an orthotic for restricting ankle RoM and offloading the foot.

METHODS

A systematic literature review was conducted in accordance with the PRISMA 2020 guidelines. All papers were independently screened by two authors for inclusion. Methodological quality was appraised using Joanna Briggs Critical Appraisal checklists. A narrative synthesis of all eligible papers was produced.

RESULTS

Thirteen studies involving 197 participants (113 male and 84 female) were included. All studies were quasi-randomised and employed a within-study design, of which 12 studies included a control group and a range of CAM boots were investigated. CAM boots can be seen to restrict ankle RoM, however, neighboring joints such as the knee and hip do have kinetic and kinematic compensatory alterations. Plantar pressure of the forefoot is effectively redistributed to the hindfoot by CAM boots.

CONCLUSION

The compensatory mechanisms at the hip and knee joint during CAM boot wear could explain the secondary site pain often reported in patients, specifically at the ipsilateral knee and contralateral hip. Although CAM boots can be used to restrict ankle motion, this review has highlighted a lack of in-boot kinematic analyses during CAM boot use, where tracking markers are placed on the anatomical structure rather than on the boot, or through video fluoroscopy, urging the need for a more robust methodological approach to achieve this. There is a need for studies to assess the biomechanical alterations caused by CAM boots in populations living with foot and ankle pathologies. Future research, adopting a longitudinal study design, is required to fully understand the effectiveness of CAM boots for rehabilitation.

The Effects of Different Myofascial Release Techniques on Pain, Range of Motion, and Muscle Strength in Athletes With Iliotibial Band Tightness: A Randomized Controlled Study

CONTEXT

We designed this study to investigate the effects of 2 myofascial release techniques, Instrument-Assisted Soft Tissue Mobilization (IASTM) and Foam Roller (FR), on pain, joint range of motion, and muscle strength in athletes suffering from iliotibial band (ITB) tightness.

DESIGN

A total of 39 male soccer players were enrolled in this randomized controlled trial, aged between 18 and 23 years who were divided into 3 groups: Only Exercise, IASTM, and FR.

METHODS

All participants performed daily strengthening and stretching exercises, while 1 group added IASTM, and the other added FR to the exercise program. We evaluated ITB tightness with the Ober test and an inclinometer, pressure pain threshold, using an algometer, and we evaluated muscle strength with the Cybex Norm Isokinetic device.

RESULTS

We found that all 3 groups exhibited an increase in the Ober inclination angle after the interventions (P = .001), but the increase was greater for participants in the IASTM and FR groups, compared with exercise alone. Additionally, both the IASTM and FR groups displayed an increased pressure pain threshold (P = .001), whereas there was no change in the control group. Moreover, while all 3 groups experienced an increase in hip muscle strength (P = .001), the IASTM and FR groups exhibited a greater increase compared with exercise alone (P = .001).

CONCLUSIONS

Based on these findings, exercise improves pain, range of motion, and muscle strength in athletes with ITB tightness, and IASTM, and FR techniques enhanced exercise effects but did not differ from one another. While our study demonstrated that both IASTM and FR techniques significantly enhance the benefits of exercise for athletes with ITB tightness, further research could delve into the long-term effects of these interventions.

Imaging of the Pediatric Knee

During normal development, imaging findings in the immature knee joint may mimic pathology or indicate transient sites of weakness, prone to injury. This article reviews the development of the knee joint, age- and maturation-dependent imaging considerations, and various developmental variants that can be encountered, subdivided into those that involve the tibiofemoral and patellofemoral compartments, soft tissues, and osseous components. The tibiofemoral compartment section reviews the focal periphyseal edema zone (FOPE), ossification variants of the femoral condyles, distal femoral metaphyseal cortical irregularity from periosteal traction, and the metaphyseal subperiosteal stripe, which should be distinguished from pathologic mimickers such as endochondral ossification dysfunction, osteochondritis dissecans (OCD), fibroosseous lesion, periosteal and subcortical pathologies. The patellofemoral compartment section includes a review of partite patella, dorsolateral defect, variant trochlear morphology, and maturation-dependent sites of transient weakness that are prone to injury from repetitive overuse (Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease) and avulsion fractures (patellar sleeve and tibial tubercle avulsions). Finally, soft tissue (discoid lateral meniscus, meniscal flounce, anterior cruciate ligament variants) and osseous components (meniscal ossicle, fabella, and cyamella) are reviewed.

The Role of MRI Scan in Sports-Related Anterior Cruciate Ligament Injuries: A Case Report-Based Literature Review

Sports-related knee injuries are a common presentation in general practice in Australia among patients of the adolescent age group. A complete understanding of the anatomy, mechanism of injury, history, focused clinical examination of the knee joint, and proper investigations can help make a proper diagnosis. Injuries can be prejudicial to ligaments, tendons, muscles, and bones. Here, we present a case of rupture of the anterior cruciate ligament (ACL) following a fall while playing football. The patient visited the emergency department where an initial radiography was performed, which was unremarkable, and was consequently discharged from the emergency department on painkillers. Later, he presented with swelling and worsening pain in general practice, and magnetic resonance imaging (MRI) confirmed a diagnosis of ACL rupture. Therefore, he was referred to an orthopedic surgeon for further treatment and management. The patient was managed conservatively and underwent physiotherapy.

Superolateral Hoffa fat pad edema in adolescent competitive alpine skiers: temporal evolution over 4 years and risk factors

OBJECTIVES

To longitudinally assess and correlate the prevalence of superolateral Hoffa fat pad (SHFP) edema with changes in features of the knee extensor mechanism in adolescent competitive alpine skiers over 48 months.

METHODS

Competitive alpine skiers were prospectively enrolled in 2018 and underwent bilateral knee MRI at baseline and after 48 months. MRI was assessed for the prevalence of SHFP edema. Features of the knee extensor mechanism were assessed by measuring the trochlear sulcus angle and depth, lateral and medial trochlear inclination, trochlear angle, patella tilt, Insall‒Salvati ratio (ISR), and patellar ligament to lateral trochlear facet (PL-T) distance. Separate logistic regression models were used to calculate the odds ratios between each measurement and the presence of SHFP edema at both time points.

RESULTS

Sixty-three athletes were included in the study (mean age 15.3 ± 1.3 years, 25 women). At baseline, 23 knees had SHFP edema, increasing to 34 knees at the 48-month follow-up. At baseline, knees with measurements in the highest quartile for ISR and lowest quartile for trochlear depth and PL-T were 9.3, 5.1, and 7.7 times more likely to show SHFP edema, respectively. At follow-up, these correlations were confirmed and additionally, knees with measurements in the highest quartile for trochlear sulcus angle and the lowest quartile for lateral trochlear inclination were 4.1 and 3.4 times more likely to show SHFP edema.

CONCLUSION

An increased prevalence of SHFP edema in competitive alpine skiers during adolescence was associated with persistent high-riding patella, reduced patellar ligament to trochlear distance, and flattened lateral trochlear facet.

CRITICAL RELEVANCE STATEMENT

In clinical routine, assessment of the mechanical properties of the knee extensor mechanism, together with anatomical developments during adolescence, may improve the understanding and management of patellofemoral instability.

KEY POINTS

• Superolateral Hoffa fat pad (SHFP) edema is a frequent cause of anterolateral knee pain but the role of predisposing factors is still debated. • A higher prevalence of SHFP edema was associated with high-riding patella, reduced patellar ligament to trochlear distance, and flattened lateral trochlear facet. • Understanding of the mechanical interaction and the anatomical development of the knee during adolescence provides further insight into the development of SHFP edema.

An Innovative Topical Medical Device with Hyaluronic Acid and Polypeptides in Patients with Reduced Knee Function

A topical medical device, AI500®, constituted of a single-chain polypeptide embedded in hyaluronic acid, was tested and evaluated in patients with reduced knee function due to osteoarthritis and other knee conditions. A total of 35 participants with reduced knee function assessed by the WOMAC Physical Function score were recruited. Four study visits were planned, from the first application at V0 to 1 week follow up at V3. Patient symptomatology was evaluated after 24 h (V1) and after 48 h (V2) through phone contact, and after 1 week from V0, on site (V3). The overall duration of the follow up was one week. An amelioration of 40% in WOMAC Physical Functional scores after 1 week of treatment was recorded, thus achieving the primary endpoint of 20%. Furthermore, a reduction of 29% in Physical Functional scores and of 28% in total WOMAC scores between V0-V2 was registered, together with a decrease of 39% between V0 and V3. The NRS scale showed a 29% and 37% reduction in pain between V0-V1 and V0-V2, respectively. Product safety was confirmed by the very low rate of adverse effects, non-device related, observed in only 2 patients out of 35, resolved spontaneously within 24-48 h. No safety concerns or risks associated with the use of the device were highlighted. There are few the studies on the topical use of HA-based gels for the treatment of knee problems. Compared to invasive intra-articular injections and oral pharmacological therapies used in cases of knee pain, the topical application of AI500® is non-invasive, safe, and appreciated by patients. Good results in terms of functional improvement and symptoms resolution were obtained in less than 1 week.

Prevalence of lower limb pain and disability in football, hockey, and floorball players

BACKGROUND

Currently there are not enough studies that compared frequent types of collective sports with regard to the prevalence of pain and disability of the lower limb.

OBJECTIVE

To determine the prevalence of lower limb pain and disability in team sports players.

METHODS

388 athletes with average age 27.26 ± 4.69, from sports clubs at the national level were included in the study. The Oxford Hip Score was used to determine the prevalence of hip pain. The International Knee Documentation Committee was used to determine the prevalence of knee pain. The Foot and Ankle Disability Index was used to determine the prevalence of ankle pain.

RESULTS

Hockey players had a prevalence of hip pain of 97.2% and a 14.3 times higher risk of developing hip pain compared with football and floorball players. Floorball players had a 81.9% prevalence of knee pain, with a 3.8 times higher the risk of knee pain compared with football and hockey. Floorball players had a 62.3% prevalence of ankle pain and a 1.8 times higher the risk of developing ankle pain compared with football and hockey players.

CONCLUSIONS

The highest percentage of knee 81.9% and ankle 62.3% pain, as well as the greatest risk of pain, was found among floorball players. Hockey players had the highest prevalence (97.2%) and risk of developing hip pain.

S.P.O.R.R.T.-A Comprehensive Approach to the Assessment and Non-Operative Management of Overuse Knee Conditions in Youth Athletes

PURPOSE OF REVIEW

The evaluation of a young athlete with an overuse injury to the knee involves a comprehensive approach. There are a number of elements to consider including assessments of skeletal maturity (biologic maturation), workload (training load + competition load), sport specialization status, and biomechanics. The type of injury and treatment, as well as future prognosis, may be influenced by these and other factors.

RECENT FINDINGS

Calculating the percentage of predicted adult height (PPAH) is a valuable tool in assessing overuse injury patterns and diagnoses in youth athletes. Modifiable and non-modifiable overuse injury risk factors require monitoring from clinicians as young athletes mature and develop over time. Training and rehabilitation programs should be adapted to account for these. In this manuscript, we seek to introduce a novel, comprehensive approach: S.P.O.R.R.T. (Skeletal Maturity, Prior Injury Risk, One Sport Specialization, Rehabilitation, Return to Play, Training Recommendations) (Fig. 1). Overuse, non-traumatic injuries to the knee in youth athletes will be presented in a case-based and evidence-based model to provide a framework for a comprehensive approach to the assessment and treatment of youth athletes with overuse injuries.

Comparison of Single and Combined Treatment with Exercise Therapy and Collagen Supplementation on Early Knee Arthritis among Athletes-A Quasi-Randomized Trial

Athletic injuries are commonly implicated in the development of early osteoarthritic (EOA) changes in the knee. These changes have a significant impact on athletic performance, and therefore the early detection of EOA is paramount. The objective of the study is to assess the impact of different interventions on individuals with EOA, particularly focusing on recreational athletes. The study aims to evaluate the effectiveness of three treatment groups in improving various aspects related to knee EOA, including pain, range of motion, strength, and function. A study was undertaken with 48 recreational athletes with EOA who were assigned to one of three groups by the referring orthopedic surgeon: collagen (Col), exercise (Ex), or collagen and exercise (ColEx) groups. All the participants received their respective group-based intervention for 12 weeks. Visual analog scale (VAS), knee flexion range of motion (ROM) knee flexors and extensors strength, and KOOS were assessed at baseline, and after 4 weeks, 8 weeks, and 12 weeks of intervention. VAS for activity improved in all treatment groups, with no difference between groups. The between-group analysis for knee ROM revealed a significant difference (p = 0.022) in the Col vs. Ex group at 12 weeks. The knee flexor and extensor strength and the KOOS scores improved considerably in the Ex and the ColEx group (p < 0.05) at 12 weeks. Exercise therapy improved pain, strength and function in subjects with EOA, whereas the association of collagen seems to have accentuated the effects of exercise in bringing about clinical improvements.

Medial Knee Joint Space in Relation to Joint Function and Early Knee Pain in 20-45-Year Adults: A Cross Sectional Study

Background

Anterior knee pain is very common in the young and active age groups but there are no significant studies on the normal population. Therefore, the objective of the study was to understand the relation between medial knee joint space to the development of knee pain and functional disability with special reference to the 20-45-year age group.

Materials and methods

250 cases with mean age of 36.36 years presenting with knee pain for at least 1 month were included in this prospective study (July 2021 and June 2022) and were asked to self-complete questionnaires on knee pain which included KNEST, AKPQ, VAS and IPAQ. Patients underwent X-rays of bilateral knees in AP view with weight bearing and then medial and lateral knee joint spaces were calculated.

Results

There was a higher incidence of knee pain in women compared to men. The average medial and lateral joint space widths (MJSW and LJSW) of the right knee were 4.22 mm and 4.57 mm, respectively. For the left knee it was 4.19 mm and 4.42 mm, respectively. There is a decrease in MJSW with increasing age, level of pain and BMI. Also, with an increase in physical activity, there was a higher incidence of knee pain.

Conclusion

Overuse injuries are the main cause of knee pain in this age group. There is a significant association between medial joint space width and age, gender, level of pain, and BMI. Rising BMI patterns at a young age, leads to an increase in physical activity, which in turn leads to early knee pain and also predisposes to osteoarthritis.

[Musculoskeletal multibody dynamics investigation for the different medial-lateral installation position of the femoral component in unicompartmental knee arthroplasty]

The surgical installation accuracy of the components in unicompartmental knee arthroplasty (UKA) is an important factor affecting the joint function and the implant life. Taking the ratio of the medial-lateral position of the femoral component relative to the tibial insert (a/A) as a parameter, and considering nine installation conditions of the femoral component, this study established the musculoskeletal multibody dynamics models of UKA to simulate the patients' walking gait, and investigated the influences of the medial-lateral installation positions of the femoral component in UKA on the contact force, joint motion and ligament force of the knee joint. The results showed that, with the increase of a/A ratio, the medial contact force of the UKA implant was decreased and the lateral contact force of the cartilage was increased; the varus rotation, external rotation and posterior translation of the knee joint were increased; and the anterior cruciate ligament force, posterior cruciate ligament force and medial collateral ligament force were decreased. The medial-lateral installation positions of the femoral component in UKA had little effect on knee flexion-extension movement and lateral collateral ligament force. When the a/A ratio was less than or equalled to 0.375, the femoral component collided with the tibia. In order to prevent the overload on the medial implant and lateral cartilage, the excessive ligament force, and the collision between the femoral component and the tibia, it is suggested that the a/A ratio should be controlled within the range of 0.427-0.688 when the femoral component is installed in UKA. This study provides a reference for the accurate installation of the femoral component in UKA.

Overuse-Related Injuries of the Knee

Overuse-related injuries of the knee joint and periarticular soft tissues include a heterogenous group of sports and nonsports-related injuries. These conditions include friction and impingement syndromes, bone stress injuries, bursitis, and tendon-related pathology such as tendinopathy and snapping. Traction apophysitis are also discussed as commonly seen in the pediatric population. Although multiple imaging modalities can be used, this review focuses on MR imaging, which is the most common and, often, the only modality used.

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.

Morphometric Parameters and MRI Morphological Changes of the Knee and Patella in Physically Active Adolescents

Background and Objectives: The immature skeleton in a pediatric population exposed to frequent physical activity might be extremely prone to injuries, with possible consequences later in adulthood. The main aim of this study is to present specific morphometric parameters and magnetic resonance imaging (MRI) morphological changes of the knee and patella in a physically active pediatric population. Additionally, we wanted to investigate the morphological risk factors for patellar instability. Materials and Methods: The study included the MRI findings of 193 physically active pediatric patients with knee pain. The participants underwent sports activities for 5 to 8 h per week. Two divisions were performed: by age and by patellar type. We evaluated three age groups: group 1 (age 11-14), group 2 (age 15-17), and group 3 (age 18-21 years). In addition, participants were divided by the patellar type (according to Wiberg) into three groups. The following morphometric parameters were calculated: lateral trochlear inclination (LTI), the tibial tubercle-trochlear groove distance (TT-TG), trochlear facet asymmetry (TFA), Insall-Salvati index, modified Insall-Salvati index, Caton-Deschamps index, articular overlap, morphology ratio and contact surface ratio. Results: We found a statistically significant association between patellar type groups in LTI (p < 0.001), TFA (p < 0.001), Insal-Salvati (p = 0.001) index, and Caton-Deschamps index (p = 0.018). According to age groups, we found statistical significance in the Caton-Deschamps index (p = 0.039). The most frequent knee injury parameter, according to Wiberg, in physically active pediatric patients was patella type 2 in boys and type 3 in girls. Conclusions: The MRI morphometric parameters observed in our study might be factors of prediction of knee injury in physically active children. In addition, it might be very useful in sports programs to improve the biomechanics of the knee in order to reduce the injury rate in sports-active children.

Stiffness of Muscles and Tendons of the Lower Limb of Professional and Semiprofessional Athletes Using Shear Wave Elastography

OBJECTIVE

Shear wave elastography (SWE) allows assessment of muscle and tendon stiffness and can be used to diagnose soft tissue pathologies such as tendinopathies. In sports medicine, SWE may have the potential to uncover structural changes early on before they lead to functional impairment. To systematically analyze possible differences in tendon and muscle stiffness of the lower limb between professional (PG) and semiprofessional female athletes (SG) using SWE and to compile reference values for developing preventive medicine approaches for professional athletes.

METHODS

Standardized SWE of both lower limb tendons and muscles (Achilles tendon [AT], soleus muscle insertion [SM], patellar tendon [PT], quadriceps tendon [QT], vastus medialis muscle [VM]) in the longitudinal plane was performed with the tendons in relaxed position in 24 healthy professional female athletes (PG) in comparison with 24 healthy semiprofessional female athletes (SG).

RESULTS

Median tendon and muscle stiffness was significantly higher in professional athletes (AT:PG, 11.12 m/s vs SG, 7.33 m/s, P < .001; SM: 1.77 m/s vs 1.14 m/s, P < .001; VM: 1.63 m/s vs 0.87 m/s, P < .001; QT: 3.31 m/s vs 2.61 m/s, P < .05). There was no significant difference in patellar tendon stiffness between PG and SG (PT: 2.57 m/s vs 3.21, P = .25).

CONCLUSION

Professional female athletes have higher stiffness values than semiprofessional female athletes in lower limb muscles and tendons, except for the patellar tendon. Knowledge of such differences is necessary for diagnosing tendinopathy and injuries. Musculoskeletal SWE could offer great benefits in sports medicine as well as in rehabilitation and preventive medicine.

Is There a Correlation Between Reported Knee Pain and Fluid at the Distal Insertion of the Iliotibial Band in Runners?

Objective

To determine whether there is a correlation between pain and the amount of fluid present at the distal insertion of the iliotibial band (ITB) in runners, as measured by USG.

Method

Our retrospective cross-sectional study evaluated 100 male and female runners prior to the start of a race. A valid and reliable questionnaire collected demographic, pain, and training data. If a runner reported knee pain, a numeric pain rating scale was used to record the degree of pain. Participants then underwent USG on both knees to determine the presence or absence of fluid at the distal insertion of the ITB.

Result

We found no statistically significant correlations of fluid measurements with pain score, running experience in years, or age. In addition, we found no other differences in fluid measurements between those with and without knee pain or between the sexes.

Conclusions

Our findings indicate that the presence or absence of fluid at the distal insertion of the ITB does not correlate with knee pain in runners, regardless of age, running experience, or sex.

The Magnetic Resonance Imaging Pattern of the Lesions Caused by Knee Overuse in the Pediatric Population

Background and Objectives: Excessive use of the knee in patients with immature locomotor systems leads to a whole spectrum of morphological changes with possible consequences in adulthood. This study aimed to examine the morphological pattern in magnetic resonance imaging (MRI) that is associated with recurrent pain due to increased physical activity in children. Materials and Methods: This was a retrospective study conducted among pediatric patients treated at the University Children’s Hospital in Belgrade in 2018 and 2019. MRI findings of patients who reported recurrent pain in the knee joint during physical activity and who were without any pathological findings on both clinical examination and knee radiographs were included in the study. Results: MRI findings of 168 patients (73 boys and 95 girls, mean age 14.07 ± 3.34 years) were assessed. Meniscus and cartilage lesions were the most commonly detected morphological findings: meniscus lesions in 49.4%, cartilage ruptures in 44.6%, and cartilage edema in 26.2% of patients. The medial meniscus was more often injured in girls (p = 0.030), while boys were more prone to other joint injuries (p = 0.016), re-injury of the same joint (p = 0.036), bone bruises (p < 0.001), and ligament injuries (p = 0.001). In children older than 15 years, tibial plateau cartilage edema (p = 0.016), chondromalacia patellae (p = 0.005), and retropatellar effusion (p = 0.011) were detected more frequently compared to younger children. Conclusions: Children reporting recurrent knee pain due to increased physical activity, without any detected pathological findings on clinical examination and knee radiography, may have morphological changes that can be detected on MRI. Timely diagnosis of joint lesions should play a significant role in preventing permanent joint dysfunction in the pediatric population as well as in preventing the development of musculoskeletal diseases in adulthood.

The influence of COVID-19 pandemic on the incidence of knee pain and physical activity level in children and adolescents in Japan: A prospective observation study

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had a profound impact on children's lifestyles. Some studies have reported psychological changes in children after the pandemic, but information on musculoskeletal problems is scarce. This study aimed to investigate the incidence of knee pain and changes in physical activity after the spread of COVID-19 among elementary and junior high school students in Japan.

METHODS

Knee pain and amount of physical activity were recorded on a monthly basis between August 2019 and February 2021 in children aged 8-14 years using a self-administered questionnaire. The amount of physical activity was scored using the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS). The period until February 2020 was defined as "Before pandemic," and the period from March 2020 was defined as "After pandemic." The incidences of knee pain and HSS Pedi-FABS scores before and after the COVID-19 pandemic were compared. Additionally, we compared the prevalence of knee pain and HSS Pedi-FABS scores according to sex and age.

RESULTS

We enrolled 886 and 881 participants before and after the pandemic, respectively. The prevalence of knee pain among the participants before and after the pandemic was 6.7% and 7.9%, respectively (p = 0.032). The mean HSS Pedi-FABS scores before and after the pandemic were 14.8 and 14.5, respectively (p = 0.005). Participants aged 14 years had a significantly lower incidence of knee pain (p = 0.013) and significantly higher HSS Pedi-FABS scores (p < 0.001) after the spread of COVID-19.

CONCLUSIONS

In elementary and junior high school students, increase in the incidence of knee pain and decrease in the amount of physical activity after the spread of COVID-19 were observed.

A Clinical Study to Evaluate the Safety and Efficacy of Oral Administration of Microscopic Dose Gold Nanoparticle (AuNP) on Knee Joint Health and Function in Arthritis Patients

The purpose of this clinical study was to determine whether gold nanoparticle (AuNP) supplementation at a dosage of 0.34 mg elemental gold per day can improve knee joint health, function, and quality of life for arthritis patients. A total of 51 participants (24 male and 27 female, age 62.1 ± 13.1) were followed for 20 weeks through a three-phase longitudinal study. Both subjective and objective parameters were used to measure changes in joint health and function, as well as quality of life. The study found patients' Knee injury and Osteoarthritis Outcome Score (KOOS) improved with statistical significance. It was reported that 71.42% of the cohort experienced improvements in their perceived knee pain and 61.22% with improvements in knee stiffness. Majority of objective measurements such as pain with range of motion and specific exercises requiring proper knee health and function did not show statistically significant improvement but did show a positive improving trend in support of AuNP supplement. Study cohort showed statistically significant improvements in two specific exercises: sit-to-stand and single-leg squat. By the end of the study, 70% of the study cohort indicated that they would continue to take the supplement even after the study concluded. Though the study has limitations and is not definitely conclusive, it was the first clinical study to show that oral micro-dosage of AuNP as low as 0.34 mg daily is safe and effective for both rheumatoid arthritis and osteoarthritis patients. This study opened way for the use of AuNP in both clinical and daily settings to improve joint health and function for both average and athletic users.

Risk factors for the occurrence and protraction of patellar and patellar tendon pain in children and adolescents: a prospective cohort study of 3 years

Background

Patellar and patellar tendon pain is a common limitation to children’s participation in social and physical activities. Some factors have been implicated in the occurrence and protraction of knee pain, but the causal relationship is unknown. The purpose of this study was to investigate whether participants’ physical characteristics and activity level are risk factors for the occurrence and protraction of patellar and patellar tendon pain in children and adolescents.

Methods

A three-year prospective cohort study was conducted with healthy students who were aged 8–14 years old, in Japan. Height, weight, heel-buttock distance, straight leg raising angle, and dorsiflexion angle of the ankle joint were collected as individual physical factors at the beginning of each year. The presence of self-reported patellar and patellar tendon pain and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) was collected every month. Protraction was defined as either (1) pain lasting for more than three continuous months or (2) recurrent pain after more than three months of complete recovery. Participants who did not have any pain at the beginning of the observation period were included in the analysis. We analyzed the odds ratio (OR) of pain occurrence within a year of registration and protraction throughout the study period for all physical factors and HSS Pedi-FABS.

Results

We included 1133 participants in the analysis and 252 participants developed knee pain within a year. 34.8% of participants with pain experienced protraction during the follow-up period. A high HSS Pedi-FABS significantly predicted knee pain occurrence (OR 1.03, 95% confidence interval [CI] 1.01–1.05) and protraction (OR 1.03, 95% CI 1.00–1.05). In addition, younger children and girls were at a significantly higher risk of patellar and patellar tendon pain protraction (age, OR 0.81, 95% CI, 0.73–0.90; sex, OR 1.69, 95% CI, 1.09–2.64). Other physical factors did not significantly predict the occurrence or protraction of knee pain.

Conclusions

This study showed that a greater physical activity level was a risk factor for the occurrence and protraction of patellar and patellar tendon pain in childhood. In addition, younger age and female sex predicted higher risk of protraction of pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05349-y.

Effect of soft tissue manipulation of popliteus muscle on quadriceps muscle activity and torque production in athletes with anterior knee pain

Study aim: Popliteus is majorly associated with posterior knee pain; however, this muscle can also have an impact on anterior knee pain. The purpose of this study was to determine the effect of soft tissue manipulation of popliteus muscle on non-traumatic anterior knee pain in athletes; as the relationship between popliteus and Quadriceps muscle has not been studied/explored much.

Materials and methods: In this experimental study, 15 subjects presenting with non-traumatic anterior knee pain were selected. Quadriceps muscle activity, torque production and knee pain were assessed. Followed by a single session of popliteus manipulation all the above parameters were re-assessed immediately and at 24 hours after intervention.

Results: Significant reduction in pain (P < 0.005) at 24 hours was observed. There was a significant increase in muscle activity of Vastus Medialis (P < 0.05) and Vastus Lateralis (P < 0.005) immediately after the intervention but not after 24 hours. No significant change was found in the activity of Rectus femoris and Peak torque of Quadriceps immediately after the intervention and at 24 hours.

Conclusion: Soft tissue manipulation decreased knee pain and improved muscle activity. Therefore, incorporating popliteus manipulation can be effective in treatment of anterior knee pain.

Alternatives to Knee Braces

Knee braces continue to be a widely utilized piece of medical equipment, ranging from simple over the counter sleeves to more complex functional braces, with the ability to provide electrical stimulation to muscle groups. Despite their popularity, alternatives to knee braces exist for patients who find braces to be ineffective, uncomfortable, cumbersome, or overly expensive. While high-quality studies are lacking for modalities such as neoprene sleeves, compression stockings, and kinesiotaping, there is promising evidence that these interventions can confer an element of stability and pain relief for a variety of knee pathologies both with regard to acute and chronic injuries as well as in the postoperative rehabilitation period. While no "holy grail" exists for the ideal brace, or bracing alternative, it is important for providers to be aware of the options available to patients as well as the current evidence for these various modalities, so that the provider can best guide musculoskeletal care.

Do Individuals with History of Patellofemoral Pain Walk and Squat Similarly to Healthy Controls? A 3D Kinematic Analysis During Pain Remission Phase

BACKGROUND

Patellofemoral pain (PFP) is typically accompanied by changes in movement pattern. However, it is unclear if these changes persist in the remission phase of symptoms. Investigating movement patterns in individuals in remission phase of PFP may help to further guide the rehabilitation process and to understand whether changes are due to high levels of pain or related to other factors.

PURPOSE

To compare 3D kinematics during walking and the single leg squat (SLS) between individuals with history of PFP in remission phase and a control group without history of lower limb injuries and PFP.

STUDY DESIGN

Cross-sectional case-control study.

METHODS

Individuals with onset of PFP for at least one year and in phase of remission of symptoms (experimental group [EG]; n=13, 30±8 years) were compared to a control group (CG, n=13, 28±7 years). A 10-camera motion analysis system (Vicon-Nexus®) was used to record 3D ankle, knee, hip and trunk angles during walking and SLS.

RESULTS

The EG presented less ankle dorsiflexion, knee and hip flexion during the stance phase of walking compared to the CG (p=0.005, large effect size ηp2 = 0.141). During the SLS, no between-group differences were observed for the ankle, knee and hip angles at the peak of knee flexion (p>0.05). A trend for increased trunk range of movement in the EG compared to the CG was observed (p=0.075, medium effect size ηp2 = 0.127).

CONCLUSION

The results of this study indicate less movement in the sagittal plane during walking, and a trend towards more movement of the trunk during SLS in the EG compared to the CG. The participants of the EG had minimal symptoms, to the point of not classifying them as pathological. However, the between-group differences suggest that even in the remission phase, kinematic differences persist for some reason and may contribute to the recurring pain in PFP individuals.

LEVEL OF EVIDENCE

Level 3.

Post-Run T2 Mapping Changes in Knees of Adolescent Basketball Players

OBJECTIVE

While articular cartilage defects are common incidental findings among adult athletes, the effect of running on the cartilage of adolescent athletes have rarely been assessed. This study aims to assess the variations in the articular cartilage of the knees in healthy adolescent basketball players using quantitative T₂ MRI (magnetic resonance imaging).

DESIGN

Fifteen adolescent basketball players were recruited (13.8 ± 0.5 years old). Girls were excluded to avoid potential gender-related confounding effects. Players underwent a pre-run MRI scan of both knees. All participants performed a 30-minute run on a treadmill. Within 15 minutes after completion of their run, players underwent a second, post-run MRI scan. Quantitative T₂ maps were generated using the echo modulation curve (EMC) algorithm. Pre-run scans and post-run scans were compared using paired t test.

RESULTS

Participants finished their 30-minute run with a mean running distance of 5.77 ± 0.42 km. Pre-run scans analysis found statistically significant (P < 0.05) changes in 3 regions of the knee lateral compartment representing the cartilaginous tissue. No differences were found in the knee medial compartment. Post-run analysis showed lower T₂ values in the medial compartment compared to the pre-run scans in several weight-bearing regions: femoral condyle central (pre/post mean values of 33.9/32.2 ms, P = 0.020); femoral condyle posterior (38.1/36.8 ms, P = 0.038); and tibial plateau posterior (34.1/31.0 ms, P < 0.001). The lateral regions did not show any significant changes.

CONCLUSIONS

Running leads to microstructural changes in the articular cartilage in several weight-bearing areas of the medial compartment, both in the femoral and the tibial cartilage.

Low Back Pain in Young Sports Players: A Cross-sectional Study in Japan

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

The purpose of this large cohort study was to assess the prevalence of low back pain (LBP) among young players participating in several types of sports.

SUMMARY OF BACKGROUND DATA

LBP is a significant problem among young sports players. Sport discipline among young players is thought to be associated with LBP. However, similar previous studies did not specifically analyze LBP by age and sex.

METHODS

A cross-sectional study was conducted with young sports players (ages 6-15 years, n = 7277) using a self-reported questionnaire. The prevalence of LBP was assessed using the variables of age, sex, and sport discipline.

RESULTS

The point prevalence of LBP among young sports players was 5.0%. The participants between 6 and 8 years' old had the lowest prevalence of LBP (0.4%-1.3%), which increased with aging and reached the highest proportion of 13.5% to 14.8% at 13 to 14 years. Furthermore, female players had significantly higher proportions of LBP than male players (8.1% vs. 3.7%). Regarding sport discipline, the prevalence of LBP was higher in basketball, handball, and volleyball.

CONCLUSION

The prevalence of LBP among young sports players was different for age, sex, and sport discipline. Further studies are needed to clarify the association of sport-specific movements to LBP in each sport discipline. This may assist in developing programs or strategies for preventing LBP among young sports players.Level of Evidence: 3.

Physeal injury in a skeletally immature male athlete

A 12-year-old skeletally immature male athlete presented for evaluation with acute bilateral knee pain. Initial radiographs revealed subtle lucency of the medial proximal tibial physis and MRI was recommended. On MRI, broad-based intravasation of the physis into the proximal femoral and tibial physes was observed. This represented physeal widening, a phenomenon that has been observed in skeletally immature athletes presenting for acute knee pain. While such changes to the physis may be quite prominent on MRI, conventional radiographic findings may be much more subtle. As many causes of chronic knee pain in this population are managed with active rehabilitation, a high index of suspicion for this diagnosis in the presence of physeal abnormalities may warrant evaluation with MRI. The literature suggests this pathology will resolve with rest, but, if weight-bearing activities are continued, there is a risk for significant growth abnormalities.

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.

Imaging of Pediatric Lower Limb Sports Injuries

The importance of physical activity during childhood and adolescence has come to light, with an increase in sports-related acute traumatic and overuse injuries as a major disadvantage. A solid understanding of the physiology of the growing skeleton, together with knowledge about age- and sex-related differences in the occurrence of acute traumatic and overuse injuries is necessary. Every musculoskeletal radiologist should also be familiar with the appearances of these injuries on different imaging modalities. This review focuses on all these aspects concerning acute traumatic and overuse injuries among children and adolescents.

Overuse Knee Pain in the Pediatric and Adolescent Athlete

Overuse knee pain is common in young athletes. There are many potential overuse injuries which present with insidious onset of pain that can challenge sports medicine providers, including Osgood-Schlatter's disease, patellofemoral syndrome, osteochondritis dissecans, and stress fractures. The differential diagnosis of insidious onset knee pain also includes malignancies, infections, and rheumatologic issues. A thorough history and physical examination can guide the treating provider in making a diagnosis and appropriate treatment plan. Although not always necessary, imaging is often helpful in overuse knee pain, and laboratory workup may be necessary. Conservative treatment is often the first recommendation in the management of overuse knee pain in young athletes, and this may include activity modification, ice, anti-inflammatory medications, bracing, and physical therapy. This review summarizes common overuse knee injuries seen in pediatric and adolescent athletes.

Comparison of Trunk Flexion Proprioception Between Healthy Athletes and Athletes With Patellofemoral Pain

OBJECTIVE

Patellofemoral pain (PFP) is the most commonly reported musculoskeletal overuse injury in active individuals, such as athletes, and is a multifactorial problem with no definite cause identified to date. Some studies have shown a relationship between impaired core and trunk sensorimotor control and knee disorders, especially PFP. The aim of this study was to evaluate trunk flexion proprioception by comparing the repositioning error between healthy athletes and athletes with PFP.

DESIGN

Cross-sectional case-control study.

SETTING

Rehabilitation sciences research center.

PARTICIPANTS

Twenty healthy athletes and 20 athletes with PFP.

MAIN OUTCOME MEASURES

To examine proprioception of trunk flexors, the absolute active and passive repositioning error at 30° and 60° trunk flexion were evaluated with isokinetic dynamometry. The results were compared between the two groups.

RESULTS

In the PFP group, the active trunk repositioning error at 30° flexion was significantly greater than in the healthy individuals (P < .001). The mean absolute active repositioning error at 30° flexion was 3.04° (1.37°) in the PFP group and 1.50° (0.70°) in the control group. There was no significant difference between groups in the active trunk repositioning error at 60° flexion (P = .066). The mean absolute active repositioning error at 60° flexion was 2.96° (1.26°) in the PFP group and 2.18° (0.99°) in the control group. The passive trunk repositioning error at 30° and 60° flexion was significantly greater in the PFP group (P = .013 and P = .004, respectively). The mean absolute passive repositioning error at 30° and 60° flexion in the PFP group was 2.94° (0.80°) and 3.13° (1.19°), respectively, and was 2.08° (1.08°) and 1.96° (0.71°), respectively, in the control group. The calculated eta-squared value showed that joint repositioning errors had large effect sizes (0.15-0.32).

CONCLUSION

Trunk proprioception in the flexion direction may be impaired in patients with PFP. This finding suggests that trunk proprioception training may be important in rehabilitation for athletes with PFP.

Management of suprapatellar synovial plica, a common cause of anterior knee pain: a clinical review

BACKGROUND AND AIM OF THE WORK

Suprapatellar synovial plica is caused by a congenital thickening of the synovial membrane and is generally asymptomatic. In the literature, suprapatellar plicae are described as one of the causes of anterior knee pain however, their real role in determining symptoms is controversial. The aim of the current paper is to describe the anatomy, classifications, pathophysiology, symptoms and management of suprapatellar plica syndrome, as well as the differential diagnosis from other causes of anterior knee pain.

METHOD

Via a search within the MEDLINE/PubMed database, a current review was conducted, and the results summarized.

RESULTS

Due to idiopathic, traumatic or inflammatory conditions, plicae can become pathological, causing anterior knee pain with possible knee clicking, swelling, giving way and locking after prolonged flexion of the knee. The diagnosis should be formulated based on an accurate medical history and clinical examination, followed by an appropriate imaging study. However, arthroscopy remains the "golden standard" for detecting all synovial plica.

CONCLUSIONS

In patients with anterior knee pain, where doubt is present in the imaging investigation for intraarticular or periarticular lesions, pathological suprapatellar synovial plica must be suspected. The treatment should initially be conservative, but in cases where symptoms persist, patients should undergo arthroscopy to confirm diagnosis and to determine a suitable treatment. In the presence of pathological plica associated with cartilage damage of the femoral condyle or patella at the time of diagnostic arthroscopy, plicae excision leads to favourable results in a high number of cases.

Three-Dimensional Quantitative Magnetic Resonance Imaging of Epiphyseal Cartilage Vascularity Using Vessel Image Features: New Insights into Juvenile Osteochondritis Dissecans

We introduce a quantitative measure of epiphyseal cartilage vascularity and examine vessel networks during human skeletal maturation. Understanding early morphological changes in the distal femoral condyle is expected to provide information on the pathogenesis of developmental diseases such as juvenile osteochondritis dissecans.

Methods

Twenty-two cadaveric knees from donors ranging from 1 month to 10 years of age were included in the study. Images of bone, cartilage, and vascularity were acquired simultaneously with a 3-dimensional gradient-recalled-echo magnetic resonance imaging (MRI) sequence. The secondary ossification center volume and total epiphysis cartilage volume ratio and articular-epiphyseal cartilage complex and epiphyseal cartilage widths were measured. Epiphyseal cartilage vascularity was visualized for 9 data sets with quantitative susceptibility mapping and vessel filtering, resulting in 3-dimensional data to inform vessel network segmentation and to calculate vascular density.

Results

Three distinct, non-anastomosing vascular networks (2 peripheral and 1 central) supply the distal femoral epiphyseal cartilage. The central network begins regression as early as 3 months and is absent by 4 years. From 1 month to 3 years, the ratio of central to peripheral vascular area density decreased from 1.0 to 0.5, and the ratio of central to peripheral vascular skeletal density decreased from 0.9 to 0.6. A narrow, peripheral vascular rim was present at 8 years but had disappeared by 10 years. The secondary ossification center progressively acquires the shape of the articular-epiphyseal cartilage complex by 8 years of age, and the central areas of the medial and lateral femoral condyles are the last to ossify.

Conclusions

Using cadaveric pediatric knees, we provide quantitative, 3-dimensional measures of epiphyseal cartilage vascular regression during skeletal development using vessel image features. Central areas with both early vascular regression and delayed ossification correspond to predilection sites of juvenile osteochondritis dissecans in this limited case series. Our findings highlight specific vascular vulnerabilities that may lead to improved understanding of the pathogenesis and better-informed clinical management decisions in developmental skeletal diseases.

Clinical Relevance

This paradigm shift in understanding of juvenile osteochondritis dissecans etiology and disease progression may critically impact future patient management. Our findings highlight specific vascular vulnerabilities during skeletal maturation in a group of active young patients seen primarily by orthopaedic surgeons and sports medicine professionals.

Eccentric Resistance Training in Youth: Perspectives for Long-Term Athletic Development

The purpose of this narrative review is to discuss the role of eccentric resistance training in youth and how this training modality can be utilized within long-term physical development. Current literature on responses to eccentric exercise in youth has demonstrated that potential concerns, such as fatigue and muscle damage, compared to adults are not supported. Considering the importance of resistance training for youth athletes and the benefits of eccentric training in enhancing strength, power, speed, and resistance to injury, its inclusion throughout youth may be warranted. In this review we provide a brief overview of the physiological responses to exercise in youth with specific reference to the different responses to eccentric resistance training between children, adolescents, and adults. Thereafter, we discuss the importance of ensuring that force absorption qualities are trained throughout youth and how these may be influenced by growth and maturation. In particular, we propose practical methods on how eccentric resistance training methods can be implemented in youth via the inclusion of efficient landing mechanics, eccentric hamstrings strengthening and flywheel inertia training. This article proposes that the use of eccentric resistance training in youth should be considered a necessity to help develop both physical qualities that underpin sporting performance, as well as reducing injury risk. However, as with any other training modality implemented within youth, careful consideration should be given in accordance with an individual's maturity status, training history and technical competency as well as being underpinned by current long-term physical development guidelines.

Age and Sex Differences in Overuse Injuries Presenting to Pediatric Sports Medicine Clinics

Pediatric overuse injuries present with a gradual mechanism of onset and an underlying pathogenesis of microtrauma. We evaluated the clinical presentation of pediatric sports injuries to determine if differences exist between age and sex. A retrospective chart review was performed over a 6-year period; 6593 overuse injuries were included with the mean age of 13.4 years. Males presented with a greater proportion of apophysis, physis, and articular cartilage injuries ( P < .01). Females presented with greater bone, tendon, and "other" injuries ( P < .01). Children <9 years of age demonstrated apophysis and physis injuries. Conversely, children older than 15 years of age presented with tendon, bone, bursa, and other ( P < .01) overuse injuries. A significant number of pediatric athletes in this cohort reported playing through pain prior to clinical evaluation. Injury prevention programs need to educate children, and a red flag should be raised when pediatric athletes are participating with pain.

Ruptured Appendicitis and Retrocecal Abscess Masquerading as Knee Pain in a Pediatric Patient: A Case Report

BACKGROUND

Knee pain has a variety of etiologies in the pediatric population, including septic arthritis, osteomyelitis, fracture, ligamentous injury, and neoplasms. Extrinsic sources of knee pain may also be intra-abdominal, although abdominal pathology is much more likely to manifest as hip or proximal thigh musculature pain.

CASE REPORT

A 5-year-old healthy male presented with atraumatic right knee pain, discomfort with weightbearing, fever, and elevated inflammatory laboratory markers. Physical examination and magnetic resonance imaging findings of the knee were benign, leading to low clinical suspicion for knee septic arthritis. Blood cultures were positive for a gastrointestinal organism, Granulicatella adiacens, suggesting abdominal pathology leading to referred pain. Ultrasound evaluation and computed tomography (CT) of the abdomen revealed a large abscess secondary to perforated appendicitis, which was treated with CT-guided drainage and i.v. antibiotics. The patient's musculoskeletal pain subsided with treatment of the appendicitis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Acute appendicitis may present as knee pain, with other signs and symptoms mimicking septic arthritis, such as fever, inability to bear weight, and elevated inflammatory markers. Considering an array of differential diagnoses in pediatric patients with apparent knee septic arthritis is crucial to prevent delay in diagnosis of alternative infectious sources.

Limb symmetry index in competitive alpine ski racers: Reference values and injury risk identification according to age-related performance levels

PURPOSE

The aims of this study were to assess differences of limb symmetry index (LSI) in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.

METHODS

The study (Study 1) included 285 high-level competitive ski racers (125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth (10-14 years, secondary modern school), 107 adolescent (15-19 years, grammar school), and 83 elite athletes (20-34 years). To investigate the second aim (Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests (strength related: one-leg counter movement jump (OL-CMJ) and one-leg isometric/isokinetic press strength test (OL-ILS); coordination related: one-leg stability test (OL-ST) and one-leg speedy jump test (OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.

RESULTS

There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ (χ²(2, 285) = 9.09; p = 0.01) and the OL-ILS (χ²(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers (Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.

CONCLUSION

Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks (strength vs. coordination related) rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.

Anterior knee pain and its intrinsic risk factors among runners in under-resourced communities in Ekurhuleni, Gauteng

Background

Anterior knee pain (AKP) is the most common injury among runners, especially in females and young runners. Because of a deficit of rehabilitation services in under-resourced communities, runners train and compete with injuries, resulting in further complications.

Objectives

This study aimed to determine the prevalence and modifiable intrinsic risk factors for AKP among runners in under-resourced communities in Ekurhuleni, Gauteng Province.

Method

This cross-sectional study included a population of 347 runners from six running clubs. Convenience sampling was used to recruit 183 participants aged between 13 and 55. A standardised questionnaire determined AKP prevalence, and 12 physical tests screened for modifiable intrinsic risk factors. Descriptive and inferential statistical tests were used to analyse the data.

Results

AKP was present in 40% of participants, particularly in males (57.9%) and young runners (57.9%) with 3–5 years of running experience (31.1%). Anterior knee pain was significantly associated with age (chi-square [χ²] = 6.484, p = 0.039) and running experience (χ² = 8.389, p = 0.036). The modifiable intrinsic risk factors found to have contributed significantly to AKP were: tight hamstrings (odds ratio [OR] = 1.021; p = 0.051); tight iliotibial band (OR = 1.1; p = 0.046); weak quadriceps (OR = 0.15; p = 0.040); weak hip muscles (OR = 1.13; p = 0.004) and patellar tilt abnormalities (OR = 1.33; p = 0.015).

Conclusion

Anterior knee pain and various modifiable intrinsic risk factors were found among these runners. These findings suggest that management of AKP should take into consideration the effect of these identified modifiable risk factors to improve management outcomes. A community-based rehabilitation approach should be considered, given the lack of resources in low socio-economic communities.

Clinical implications

The results from this study make explicit the risk factors associated with AKP, particularly in runners from under-resourced communities. These are important considerations in the development of rehabilitation programmes to manage AKP.