Patellofemoral Instability in Children: Correlation Between Risk Factors, Injury Patterns, and Severity of Cartilage Damage.

OBJECTIVE: The purpose of this study was to compare MRI findings between groups with and without patellofemoral instability and to correlate the MRI findings with the severity of patellar cartilage damage. MATERIALS AND METHODS: Fifty-three children with patellofemoral instability and 53 age- and sex-matched children without patellofemoral instability (15.9 ± 2.4 years) were included. Knee MRI with T2-weighted mapping was performed. On MR images, femoral trochlear dysplasia, patellofemoral malalignment, medial retinaculum injury, and bone marrow edema were documented. The degree of patellar cartilage damage was evaluated on MR images by use of a morphologic grading scale (0-4) and on T2 maps with mean T2 values at the medial, central, and lateral facets. MRI findings were compared between the two groups. In cases of patellofemoral instability, MRI findings were correlated with the severity of cartilage damage at each region. RESULTS: Trochlear structure and alignment were significantly different between the two groups (Wilcoxon p < 0.0001). In patellofemoral instability, a high-riding patella was associated with central patellar cartilage damage with a higher morphologic grade and T2 value (Spearman p < 0.05). The severity of medial retinacular injury and presence of bone marrow edema at either the medial patella or the lateral femoral condyle were associated with a higher grade of medial patellar cartilage damage (Wilcoxon p < 0.05). None of the other findings correlated with the severity of patellar cartilage damage. CONCLUSION: Patients with patellofemoral instability have significantly different trochlear structure and alignment than those who do not, and these differences are known risk factors for patellofemoral instability. However, the only risk factors or injury patterns that directly correlated with the severity of patellar cartilage damage were patella alta, medial stabilizer injury, and bone marrow edema.

Patellofemoral instability in children: T2 relaxation times of the patellar cartilage in patients with and without patellofemoral instability and correlation with morphological grading of cartilage damage.

BACKGROUND: Patellofemoral instability is one of the most common causes of cartilage damage in teenagers. OBJECTIVE: To quantitatively evaluate the patellar cartilage in patients with patellofemoral instability using T2 relaxation time maps (T2 maps), compare the values to those in patients without patellofemoral instability and correlate them with morphological grades in patients with patellofemoral instability. MATERIALS AND METHODS: Fifty-three patients with patellofemoral instability (mean age: 15.9 ± 2.4 years) and 53 age- and gender-matched patients without patellofemoral instability were included. Knee MR with axial T2 map was performed. Mean T2 relaxation times were obtained at the medial, central and lateral zones of the patellar cartilage and compared between the two groups. In the patellofemoral instability group, morphological grading of the patellar cartilage (0-4) was performed and correlated with T2 relaxation times. RESULTS: Mean T2 relaxation times were significantly longer in the group with patellofemoral instability as compared to those of the control group across the patellar cartilage (Student's t-test, P<0.05) with the longest time at the central area. Positive correlation was seen between mean T2 relaxation time and morphological grading (Pearson correlation coefficiency, P<0.001). T2 increased with severity of morphological grading from 0 to 3 (mixed model, P<0.001), but no statistical difference was seen between grades 3 and 4. CONCLUSION: In patellofemoral instability, patellar cartilage damage occurs across the entire cartilage with the highest T2 values at the apex. T2 relaxation times directly reflect the severity in low-grade cartilage damage, which implies an important role for T2 maps in differentiating between normal and low-grade cartilage damage.

Spatial variation of T2 relaxation times of patellar cartilage and physeal patency: an in vivo study in children and young adults.

OBJECTIVE: The purpose of this study was to determine whether the T2 spatial variation of patellar cartilage is different between children and young adults with open and closed physes. MATERIALS AND METHODS: Fifty-two subjects in two age ranges were included; 13 girls and 13 boys from 5 to 11 years old, and 13 female young adults and 13 male young adults from 17 to 22 years old. T2 maps of patellar cartilage were generated at 1.5 T. Physeal patency and mean T2 relaxation times as a function of normalized distance (T2 spatial variation) were evaluated in each group and sex. RESULTS: All the subjects from 5 to 11 years old had open physes and all the subjects from 17 to 22 years old had closed physes. Mean T2 relaxation times of patellar cartilage in the open physis group were significantly longer than in the closed physis group throughout all normalized distances across patellar cartilage (p<0.05). There were significant differences in T2 spatial variation between the two groups (p<0.05). The open physis group had longer mean T2 relaxation times at the osteochondral area and articular cartilage than in the central portion. The closed physis group had shorter mean T2 relaxation times in the osteochondral area, with a gradual increase to longer values at the articular surface. Differences in T2 spatial variation were greatest at the osteochondral junction (p<0.05). There was no statistically significant sex difference in T2 spatial variation in either group. CONCLUSION: T2 spatial variation is different between skeletally immature and mature patellar cartilage. This difference is most prominent at the osteochondral junction and likely relates to the presence or absence of ongoing endochondral ossification.

Age and sex dependency of cartilage T2 relaxation time mapping in MRI of children and adolescents.

OBJECTIVE: T2 relaxation times on MRI are sensitive to the configuration of cartilage collagen and continually increase during aging in adults. In children, T2 relaxation times increase as a result of cartilage microstructure changes in early inflammatory arthritis. The purpose of this study was to determine age- and sex-related differences in T2 mapping of the patellar cartilage in children and adolescents during normal skeletal maturation. MATERIALS AND METHODS: Ninety-seven subjects (age range, 5-22 years; 51 females and 46 males; mean age, 14.3 and 13.7 years, respectively) without patellofemoral instability or inflammatory arthritis were included. All subjects underwent 1.5-T knee MRI with T2 mapping. The mean T2 relaxation time and thickness of the patellar cartilage were documented for each MRI examination. Skeletal maturation was determined by physeal patency (open; or closed or closing) on MRI. The associations between T2 relaxation times, cartilage thickness, sex, age, and physeal patency were assessed using Wilcoxon rank sum test and least-squares means regression models. RESULTS: T2 relaxation times and thickness of the patellar cartilage significantly decreased (p<0.0001) with increasing chronologic age. T2 relaxation times and cartilage thickness in the open physis group were found to be greater than in the closed or closing physis group (p<0.0001). T2 relaxation times and cartilage thickness were greater in males than in females (p<0.05). CONCLUSION: In contrast to senescent changes in adults, skeletal maturation in children results in a sequential decrease in T2 relaxation times that are age- and sex-dependent. Similar to cartilage in adults, cartilage in children gets progressively thinner during skeletal maturation.

The patellofemoral joint: do age and gender affect skeletal maturation of the osseous morphology in children?

BACKGROUND: The osseous morphology of the patellofemoral joint is an independent factor that affects the biomechanics of patellofemoral instability. OBJECTIVE: The purpose of this study is to determine age- and gender-related differences in the osseous morphology of the patellofemoral joint in children during skeletal maturation. MATERIALS AND METHODS: This study was approved by the institutional review board and was HIPAA-compliant. We included 97 children and young adults (age range 5-22 years; 51 girls and 46 boys, mean ages 14.3 years and 13.7 years, respectively). We studied 1.5-T knee MR exams, measuring the osseous morphology of the patellofemoral joint (lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, patellar height ratio, tibial tubercle-trochlear groove distance, and lateral patellofemoral angle) for each MR exam. We compared measurements to published values for patellofemoral instability. Physeal patency (open or closing/closed) was determined on MR. We assessed the associations between MR osseous measurements and gender, age and physeal patency using Wilcoxon rank sum test and least square means regression models. RESULTS: The osseous patellofemoral joint morphology measurements were all within a normal range. There were no significant correlations between MR osseous measurements and age, gender or physeal patency. CONCLUSION: During skeletal maturation, age and gender do not affect the osseous morphology or congruency of the patellofemoral joint.

Analysis of fatty infiltration and inflammation of the pelvic and thigh muscles in boys with Duchenne muscular dystrophy (DMD): grading of disease involvement on MR imaging and correlation with clinical assessments.

BACKGROUND: Prior reports focus primarily on muscle fatty infiltration in Duchenne muscular dystrophy (DMD). However, the significance of muscle edema is uncertain. OBJECTIVE: To evaluate the frequency and degree of muscle fat and edema, and correlate these with clinical function. MATERIALS AND METHODS: Forty-two boys (ages 5-19 years) with DMD underwent pelvic MRI. Axial T1- and fat-suppressed T2-weighted images were evaluated to grade muscle fatty infiltration (0-4) and edema (0-3), respectively. Degree and frequency of disease involvement were compared to clinical evaluations. RESULTS: Gluteus maximus had the greatest mean fatty infiltration score, followed by adductor magnus and gluteus medius muscles, and had the most frequent and greatest degree of fatty infiltration. Gluteus maximus also had the greatest mean edema score, followed by vastus lateralis and gluteus medius muscles. These muscles had the most frequent edema, although the greatest degree of edema was seen in other muscles. There was correlation between cumulative scores of fatty infiltration and all clinical evaluations (P < 0.05). CONCLUSION: In DMD, the muscles with the most frequent fatty infiltration had the greatest degree of fatty infiltration and correlated with patient function. However, the muscles with the most frequent edema were different from those with the greatest degree of edema. Thus, edema may not predict patient functional status.

Segmental Testicular Infarction, an Underdiagnosed Entity: Case Report with Histopathologic Correlation and Review of the Diagnostic Features.

A 30-year-old male presented with a 1-day history of left scrotal pain and a tender left testicle and epididymis on physical exam. Scrotal ultrasound showed an avascular, heterogeneous, hypoechoic lesion in the superior left testis suggestive of infarction or neoplasm. The patient was managed conservatively; however, his pain continued and follow-up ultrasound 6 days later showed interval increase in the size of the mass. Left radical orchiectomy was done and pathology result showed segmental infarction of the left testis.

The debate is still open; benign or malignant: a case report of a multifocal epithelioid haemangioma of fibula.

In this case, we report an epithelioid haemangioma (EH) of the fibula with ill-defined multifocal lesions and a resultant pathologic fracture. Based on radiographic appearance, these lesions were initially thought to represent a malignant process, such as primary malignant bone tumour, metastases or multiple myeloma. Osseous EHs are rare. Although they can present as multifocal lesions, the majority of bony EHs are solitary and arise in the diaphysis or metaphysis of long tubular bones, with a predilection for the lower extremity. Non-specific radiological findings, debatable cytological appearance and unpredictable clinical growth patterns commonly cause misdiagnosis of malignancy. To the best of our knowledge, a case of EH with multiple growing lesions of the fibula has not yet been reported in the literature.

Congenital Medial Meniscus Hypoplasia.

An 18-year-old man with no prior surgical history presented with left knee pain after sustaining a basketball injury and was diagnosed with transient patellar dislocation. Magnetic resonance imaging was ordered to further assess the extent of injury.