MRI of Sports Injuries in Children and Adolescents: What’s Different from Adults

Imaging of Disease and Normal Variant Patterns in Pediatric Hips

The pediatric hip undergoes significant changes from infancy through adolescence. Proper maturation is crucial for the development of a stable and functional hip joint. Imaging interpretation of the pediatric hip requires distinguishing normal variants and maturation patterns from pathology. We review femoral ossification centers, variants, and conditions that affect the proximal femur, such as Legg-Calvé-Perthes disease; the acetabulum, such as developmental hip dysplasia; the acetabular labrum, such as femoroacetabular impingement; and synovial pathology in children through adolescence. Understanding the spectrum of hip conditions and using advanced imaging techniques are essential for the accurate diagnosis and effective management of pediatric hip disorders.

Should isolated superolateral Hoffa's fat pad edema identified by MRI be reported or ignored in adolescent patients?

BACKGROUND AND OBJECTIVE

The presence of superolateral Hoffa's fat pad (SHFP) edema is associated with several morphometric measurements related to patellar alignment and trochlear morphology. Our aim is to evaluate management implications in adolescent patients with isolated superolateral Hoffa's fat pad edema on MRI.

MATERIALS AND METHODS

Retrospective review of 117 adolescents with knee MRI (mean 14.8 years old) with isolated superolateral Hoffa's fat pad edema. Patients with edema were separated into two groups based on the number of MRI axial slices involved with edema: group 1 (G1) of 27 patients with 1 slice vs group 2 (G2) of 90 patients with 2 or more slices. A comparison control group was used (45 patients who had normal MRI knees). Data points included % referral for physical therapy (PT) or surgery, Hoffa's fat pad edema, tibial tubercle-trochlear groove (TT-TG) distance and lateral trochlear inclination (LTI) angle. Fisher's exact and independent t-tests, ANOVA and regression models were used for statistical analysis.

RESULTS

There is statistically significant difference between Hoffa's fat pad edema patients and control regarding PT referral with G1: 70%, G2: 76%, and control: 53% (p = 0.03). There is statistically significant difference between these groups regarding TT-TG measurements with higher values in edema groups; G1: 11.9 mm±4.1, G2 13 mm ±4.1, and control 8.7 mm±3.6, (p = 0.001). There was a statistically significant association between edema and increased TT-TG distance (p = 0.001) but not LTI angle (p = 0.2).

CONCLUSION

MRI identification of isolated superolateral Hoffa's fat pad edema is positively associated with TT-TG distance and its presence is associated with higher referral rates to physical therapy for patella maltracking.

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.

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.

Acetabular Labral Tear with a Missed Posterior Wall Fracture in an Adolescent Athlete: A Case Report

CASE

We present an adolescent contact-sport athlete presenting with hip pain after a traumatic in-play event. After delayed clinical improvement, a magnetic resonance arthrogram (MRA) revealed a posterior acetabular labral tear and the patient was referred for arthroscopic repair. However, subsequent critical interpretation of the MRA demonstrated a missed concomitant posterior acetabular wall fracture, which was later confirmed with computed tomography.

CONCLUSION

Despite the low incidence of acetabular fractures in adolescents, this case report highlights the importance of maintaining clinical suspicion in young athletes after a traumatic injury, recognizing the association with labral tears, and acknowledging the limitations of certain imaging modalities.

Pediatric Sports Injuries

Pediatric sports injuries are becoming more prevalent as children participate in sports. This has resulted in more imaging of pediatric injuries. The growing skeleton has features that result in unique injury patterns and radiologic findings. The article discusses the special features of bones including the growth plate, apophyses, cortex, and periosteum. Pediatric-specific sports injuries and conditions in the most common joints are then reviewed including the elbow, hip, and knee. The imaging appearances of these entities will be described with a multimodality approach including radiographs, CT, ultrasound, and MRI. The most important radiologic findings to identify will be highlighted throughout the article.

The Importance of the Deep Deltoid Ligament Repair in Treating Supination-External Rotation Stage IV Ankle Fracture: A Comparative Retrospective Cohort Study

Background

The necessity of the deep deltoid ligament repair in the treatment of supination-external rotation (SER) ankle stage IV fracture with deltoid ligament rupture is highly debated. We conducted this retrospective research aimed at exploring the curative effect of the deep deltoid ligament repair in treating SER fracture.

Methods

Sixty-three patients with closed SER stage IV fractures received open reduction and internal fixation (ORIF), using either deep deltoid ligament repair (the DDLR group, 31 patients) or nondeep deltoid ligament repair (the NDDLR group, 32 patients). The radiographic parameters examined include the talocrural angle (TA), fibular length (FL), tibiomedial malleolar angle (TMMA), medial clear space (MCS), and tibiofibular clear space (TFCS). The functional performance parameters examined in the study were visual analog scale (VAS) pain score, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scales, and range of motion of bilateral ankles (RMBA). Complications, including bone nonunion, infection, and fragment displacement, were also recorded and compared.

Results

Similar basic characteristics were found in both cohorts. All patients completed follow-up ranging from 12 to 22 months (mean time: 12.41 ± 4.21 months). The DDLR group had significantly reduced VAS score (p < 0.05), with markedly increased RMBA (p < 0.05) compared to the NDDLR group. The two cohorts showed similar follow-up performance at 3 months (p > 0.05), 6 months (p > 0.05), and 12 months (p > 0.05), in terms of parameters including TA, FL, TMMA, MCS, TCS, and AOFAS ankle-hindfoot scales.

Conclusion

Although similar radiographic performances were achieved in both cohorts, the DDLR group displayed enhanced functional outcome postsurgery, indicating that DDLR may be a better potential for the treatment of SER stage IV fracture with deltoid ligament rupture.

Clinical experiences of focal periphyseal edema zones in adolescent knees: case reports

Focal periphyseal edema (FOPE) zones were first described in 2011. The aim of this report was to investigate the clinical course of patients with FOPE zones. Three adolescent patients with a FOPE zone in the knee were treated and observed for a maximum of 2 years. No symptoms or leg-length discrepancy developed at the final follow-up after conservative therapies. This is the first report on the follow-up of FOPE zones with a maximum of 2 years. The results suggest that observation of FOPE zones may be sufficient without invasive examinations and treatment.

Unusual Presentations of Focal Periphyseal Edema Zones: A Report of Bilateral Symmetric Presentation and Partial Physeal Closure

Focal periphyseal edema (FOPE) zones are areas of periphyseal edema seen near the time of physeal closure which are believed to be a physiologic phenomenon related to changes in distribution of forces around the physis as it closes. Since the original case series describing these areas of periphyseal edema, there has been little published in regard to FOPE zone outside of review articles. We present a set of three patients identified with focal periphyseal edema zones around the knee and compare our findings with the initial case series. We include a patient presenting with bilateral, nearly symmetric, focal periphyseal edema zones of the proximal tibia physis and a patient with partial closure of the physis at time of presentation, which were not reported in the original case series.