MRI findings of growth plate fractures of the knee: are there age- and fracture-dependent differences?

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.

Imaging of sports injuries in adolescents

Musculoskeletal injuries in adolescents tend to occur in particular locations and have distinct characteristics, as they affect an immature skeleton. Increased engagement in sports, extended training and competition periods, and early specialization in specific sports, among other factors, have contributed significantly to the rise in musculoskeletal sports injuries in adolescents. Furthermore, females show a particularly pronounced increase in sports participation, where anatomical and hormonal factors play crucial roles in the development and increased frequency of sports-related injuries. Consequently, there is a growing demand for diagnostic imaging techniques. Musculoskeletal and pediatric radiologists require a comprehensive understanding of intrinsic and extrinsic risk factors and the successive stages of skeletal development that can influence the specific characteristics of sports injuries in adolescents. These aspects are crucial for the diagnostic, prognostic, and therapeutic management of these injuries and for mitigating chronic conditions that could compromise future sports participation. This review analyzes the primary musculoskeletal injuries in adolescent athletes and highlights the pivotal role of different imaging methods in their diagnosis and management.

Pediatric foot fractures on radiographs: distribution and predictors of surgery

PURPOSE

To examine the distribution and characteristics of pediatric foot fractures on radiographs with respect to age and skeletal maturation, and to identify predictors of surgery.

METHODS

This retrospective study included children (≤ 18 years) with foot fractures, who underwent radiographic examinations (2020-2022). Electronic medical records were reviewed to obtain demographic and clinical data. Fracture characteristics, including anatomic location, presence of displacement, angulation, articular involvement, and, if skeletally immature, physeal involvement and Salter-Harris fracture pattern were collected. Logistic regression models were used to identify predictors of surgery.

RESULTS

1,090 (596-boys, 494-girls; mean age, 11.0 ± 4.0 years) patients with 1,325 (59.8% metatarsal, 33.8% phalangeal, and 6.4% tarsal) fractures were included. Fractures of 1st metatarsal were more common among younger children whereas fractures of 2nd-4th and 5th metatarsals were more common among older children (median ages: 5.9 years vs. 10.3 years and 12.4 years, p < 0.001). Intra-articular fractures were more common among maturing and mature than immature bones (25.3% and 20.4% vs. 9.9%, p < 0.001). Physeal involvement was uncommon (162/977, 16.6%) and the most common pattern was Salter-Harris type II (133/162, 82.1%). A minority (47/1090, 4.3%) of patients required surgery and independent predictors of surgery included physeal involvement (OR = 5.12, 95% CI: 2.48-10.39, p < 0.001), multiple fractures (OR = 3.85, 95% CI: 1.67-8.53, p = 0.001), fracture displacement (OR = 9.16, 95% CI:4.43-19.07, p < 0.001), and articular involvement (OR = 2.72, 95% CI:1.27-5.72, p = 0.008). Using these predictors, the likelihood for surgery ranged between 8.0% with 1 and 86.7% with 3 predictors.

CONCLUSION

Pediatric foot fracture patterns differed based on age and regional skeletal maturation. Physeal involvement, multiple fractures, fracture displacement, and articular involvement were independent predictors of surgery in our study group.

Youth soccer players: patterns of injury involving the primary growth plates of epiphyses

Youth soccer (football) is immensely popular internationally. Earlier participation, sport sub-specialization, and year-around practice have led to an increased incidence of injury from both acute trauma and repetitive overuse. The growth plates (physes) of the immature skeleton are particularly vulnerable to injury and delayed diagnosis can lead to future growth disturbance and long-term morbidity. Familiarity with the various components of the growth plate complex necessary for ensuring normal endochondral ossification is fundamental in understanding the various patterns of imaging findings following injury. This review discusses the zonal columnar arrangement of the growth plate proper and the contrasting function of the vasculature within the subjacent epiphysis and metaphysis. This is followed by an evidence-based discussion of the common patterns of injury involving the epiphyseal primary growth plate observed among youth soccer players: subcategorized into physeal fractures (direct injury) and physeal stress injuries (indirect insult to subjacent metaphysis). In this section, the role of imaging and characteristic imaging features will be discussed. While the normal physiologic and pathophysiologic mechanisms can be applied to other growth plates, such as primary growth plates underlying the apophyses and secondary growth plates surrounding the secondary ossificiation centers, which also undergo endochondral ossification, the current review is focused on injuries involving the primary growth plates underlying epiphyses.

Minimally Invasive Percutaneous Leverage Reduction in the Treatment of Pediatric Salter-Harris IV and V Distal Femoral Physeal Fractures

OBJECTIVE

Distal femoral physeal fractures (DFPF) are rare but severe injuries in children, and there is no consensus on treatments for Salter-Harris (S-H) IV and V type of DFPF yet. This study aimed to introduce a minimally invasive technique using percutaneous leverage reduction combined with Kirschner wires fixation in treating pediatric DFPF with S-H IV and V type of injury and evaluate the clinical results.

METHODS

From July 2008 to June 2018, the authors' institute (Union Hospital, Tongji Medical College) retrospectively reviewed all patients diagnosed with pediatric DFPF. They were divided into two groups according to received treatment: children in the minimally invasive technique group were treated with a minimally invasive percutaneous leverage reduction technique, and the traditional technique group included the other children who received the conventional open reduction with internal fixation (ORIF). The surgical and clinical results of the two groups were collected and analyzed. The independent sample t-test analysis and the chi-square test were applied to compare continuous and categorical variables.

RESULTS

A total of 14 pediatric patients were recruited, including five females and nine males with DFEF. All eight patients in the minimally invasive technique group and four of the six patients in the ORIF group were treated successfully. One patient in the minimally invasive technique group opted for conservative treatment due to his good functional recovery, while the other two patients in the ORIF group needed further surgery because of the limb length discrepancy. There was a difference in surgery duration (p < 0.001), intraoperative fluoroscopy numbers (p = 0.006), intraoperative blood loss (p < 0.001), radiological union time (p = 0.003) and knee flexion angle (p < 0.001) between two groups. Patients in the minimally invasive technique group all received total knee society (KSS) scores, while the average scores in the ORIF group were lower (100.00 vs. 97.67).

CONCLUSION

The minimally invasive technique is better than conventional ORIF in terms of surgery duration, intraoperative blood loss, radiological union time, knee flexion angle and average KSS score. This percutaneous leverage reduction technique might be a good alternative for treating S-H IV and V DFPF in children.