Reliability of Radiologic Assessments of Clinically Relevant Growth Remaining in Knee MRI of Children and Adolescents With Patellofemoral Instability: Data From the JUPITER Cohort.

BACKGROUND: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on a patient's skeletal maturity. To be clinically useful, radiologic assessments of skeletal maturity must demonstrate acceptable interrater reliability and accuracy. PURPOSE: The purpose of this study was to examine the interrater reliability among surgeons of varying experience levels and specialty training backgrounds when evaluating the skeletal maturity of the distal femur and proximal tibia of children and adolescents with patellofemoral instability. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: Six fellowship-trained orthopaedic surgeons (3 pediatric orthopaedic, 2 sports medicine, and 1 with both) who perform a high volume of patellofemoral instability surgery examined 20 blinded knee radiographs and magnetic resonance images in random order. They assessed these images for clinically relevant growth (open physis) or clinically insignificant growth (closing/closed physis) remaining in the distal femoral and proximal tibial physes. Fleiss' kappa was calculated for each measurement. After initial ratings, raters discussed consensus methods to improve reliability and assessed the images again to determine if training and new criteria improved interrater reliability. RESULTS: Reliability for initial assessments of distal femoral and proximal tibial physeal patency was poor (kappa range, 0.01-0.58). After consensus building, all assessments demonstrated almost-perfect interrater reliability (kappa, 0.99 for all measurements). CONCLUSION: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on radiologic assessment of skeletal maturity. This study found that initial interrater reliability of physeal patency and clinical decision making was unacceptably low. However, with the addition of new criteria, a consensus-building process, and training, these variables became highly reliable.

The corona mortis: is it a rare and dangerous anomaly in adolescents undergoing periacteabular osteotomy?

The corona mortis (CM) is a vascular connection between the obturator and external iliac or internal epigastric vessels that has historically been identified as a source of hemorrhage in pelvic surgery. However, its frequency, location, proximity to the osteotomies performed, vascular contributions and impact on blood loss in patients undergoing periacetabular osteotomy (PAO) are unknown. We sought to identify the frequency, origin, location relative to osteotomies performed during surgery and impact on blood loss of the CM. Preoperative magnetic resonance imaging (MRI) of the hips of 28 adolescent patients (56 hips) undergoing PAO was retrospectively reviewed for the presence of a CM. When identifiable, the size, nature (arterial or venous), orientation, position relative to the iliopectineal eminence (IPE) and associated estimated blood loss (EBL) were recorded. 75% (21/28) of patients possessed an identifiable, ipsilateral CM to the site of PAO, 90% of which were venous and 10% arterial. The vessel was typically 8.3 ± 3.8 mm medial and 11.1 ± 5.3 mm caudal from the anterosuperomedial edge of the IPE. There was no significant difference in the amount of EBL (519 ± 260 versus 694 ± 369 ml) or need for post-op transfusions (1/21 versus 0/7) between patients who possessed a CM and those who did not, respectively (P = 0.21). CM was more prevalent in this study than previously reported. However, the presence of an ipsilateral CM was not associated with an increase in EBL or transfusion during routine PAO surgery using modern surgical techniques.

A Newborn With Abdominal Pain.

A previously healthy 3-week-old boy presented with 5 hours of marked fussiness, abdominal distention, and poor feeding. He was afebrile and well perfused. His examination was remarkable for localized abdominal tenderness and distention. He was referred to the emergency department in which an abdominal radiograph revealed gaseous distention of the bowel with a paucity of gas in the pelvis. Complete blood cell count and urinalysis were unremarkable. His ongoing fussiness and abnormal physical examination prompted consultation with surgery and radiology. Our combined efforts ultimately established an unexpected diagnosis.

Diffuse phalangeal signal abnormality on magnetic resonance imaging: phalangeal microgeodic disease.

BACKGROUND: Phalangeal microgeodic disease is a rare and benign self-limited condition involving the phalanges, often in the setting of cold exposure, with characteristic MR imaging abnormalities. Radiographic case descriptions are predominantly from Asia and Europe, with only seven cases using MR to characterize phalangeal microgeodic disease. OBJECTIVE: In this study we describe the MR imaging appearance of unusual and striking phalangeal signal abnormality compatible with phalangeal microgeodic disease at our institution in North America. MATERIALS AND METHODS: We retrospectively reviewed cases presenting at our institution with unusual or unexplained phalangeal signal abnormalities between 2001 and 2014. We reviewed the MR imaging appearances in conjunction with radiographs and any other available imaging investigations. RESULTS: Of 189 examinations reviewed during the study period, 8 imaging studies in 6 patients met the study inclusion criteria. Signal abnormality was present in 57 of 112 phalanges (51%), frequently involving the distal phalanges (70%, 28 of 40), followed by the middle phalanges (56%, 18 of 32) and the proximal phalanges (28%, 11 of 40). The pattern of involvement was most commonly diaphysis (38%), followed by metaphysis (32%) and epiphysis (30%). The extent of MR signal abnormality was greater than that suspected based on clinical presentation or on radiographs. CONCLUSION: The presence of unexplained diffuse characteristic marrow involvement of multiple painful phalanges on MR images, often in the setting of cold exposure, should raise the possibility of phalangeal microgeodic disease. Consideration of this diagnosis based on MR findings would lead to a more conservative management and avoid unnecessary invasive diagnostic procedures.

Pediatric elbow fractures: a new angle on an old topic.

BACKGROUND: The three most common elbow fractures classically reported in pediatric orthopedic literature are supracondylar (50-70%), lateral condylar (17-34%), and medial epicondylar fractures (10%), with fractures of the proximal radius (including but not limited to fractures of the radial neck) being relatively uncommon (5-10%). Our experience at a large children's hospital suggests a different distribution. OBJECTIVE: Our goals were (1) to ascertain the frequency of different elbow fracture types in a large pediatric population, and (2) to determine which fracture types were occult on initial radiographs but detected on follow-up. MATERIALS AND METHODS: Review of medical records identified 462 children, median age 6 years and interquartile range for age of 4-8 years (range 0.8-18 years), who were diagnosed with elbow fractures at our institution over a 10-month period. Initial and follow-up radiographs were reviewed in blinded fashion independently by two experienced pediatric musculoskeletal radiologists to identify fracture types on initial and follow-up radiographs. RESULTS: The most common fractures included supracondylar (n = 258, 56%), radial neck (n = 80, 17%), and lateral condylar (n = 69, 15%). Additional fractures were seen on follow-up exams in 32 children. Of these, 25 had a different fracture type than was identified on initial radiographs. The most common follow-up fractures were olecranon (n = 23, 72%), coronoid process (n = 4, 13%) and supracondylar (n = 3, 9%). Olecranon fractures were significantly more common on follow-up radiographs than they were on initial radiographs (n = 33, 7%; P < .0001). Twenty-six children had more than one fracture type on the initial radiograph. The most common fracture combinations were radial neck with olecranon (n = 9) and supracondylar with lateral condylar (n = 9). CONCLUSION: Supracondylar fractures are the most frequent elbow fracture seen initially, followed by radial neck, lateral condylar, and olecranon fractures in a distribution different from what has been historically described. The relatively high frequency of olecranon fractures detected on follow-up speaks to their potentially occult nature. Careful attention to these areas is warranted in children with initially normal radiographs.

Rotator cuff tears in children and adolescents: experience at a large pediatric hospital.

BACKGROUND: Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation. OBJECTIVE: The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes. MATERIALS AND METHODS: We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available. RESULTS: Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between rotator cuff tears and physeal patency (P > 0.05). Most patients were athletes (76%). Five tears were confirmed at surgery. Poor clinical follow-up limited evaluation of patient outcomes. CONCLUSION: Rotator cuff tears can be identified during MRI examination of symptomatic child and adolescent shoulders and often consist of tear patterns associated with repetitive microtrauma in overhead athletic activities or with single traumatic events. Rotator cuff tears are seen throughout the range of skeletal maturity, often coexist with labral tears and typically are found in athletes.

Tibial nerve intraneural ganglion cyst in a 10-year-old boy.

Intraneural ganglion cysts are uncommon cystic lesions of peripheral nerves that are typically encountered in adults. In the lower extremity, the peroneal nerve is most frequently affected with involvement of the tibial nerve much less common. This article describes a tibial intraneural ganglion cyst in a 10-year-old boy. Although extremely rare, intraneural ganglion cysts of the tibial nerve should be considered when a nonenhancing cystic structure with intra-articular extension is identified along the course of the nerve. This report also details the unsuccessful attempt at percutaneous treatment with US-guided cyst aspiration and steroid injection, an option recently reported as a viable alternative to open surgical resection.

Elbow plica syndrome: presenting with elbow locking in a pediatric patient.

This case report is of a symptomatic posterior-lateral elbow plica in a child who presented with elbow locking. MR images demonstrated thickening of a posterior-lateral plica between the radius and capitellum of the elbow. Surgery confirmed a thickened and inflamed posterior-lateral plica, which was resected with subsequent improvement of the child's symptoms. This case shows the clinical importance of identifying thickening of posterior-lateral plicae in children and suggesting the diagnosis of plica syndrome, an entity that has not been previously reported in children in the radiologic literature.

Juvenile dermatomyositis: correlation of MRI at presentation with clinical outcome.

OBJECTIVE: The clinical course of juvenile dermatomyositis (JDMS) is unpredictable. MRI is used to determine muscle biopsy site and to monitor disease activity. It is unknown whether soft-tissue features on MRI obtained at diagnosis correlate with clinical outcome. The purpose of our study is to determine whether initial MRI findings in the pelvis and thighs in children with JDMS can predict clinical disease course. MATERIALS AND METHODS: Forty-five children (31 girls and 14 boys; median age, 6 years; range, 1-18 years) with clinically diagnosed biopsy-proven JDMS and at least 24 months of clinical follow-up were included. Clinical outcome was categorized as limited or chronic disease, according to the established Crowe clinical classification scheme. Pretreatment MRI examinations of the pelvis and thighs were evaluated for signal abnormalities of muscle and fascia and reticulated signal changes in subcutaneous fat; associations with clinical outcome were examined. RESULTS: Twenty-two patients had limited disease and 23 had chronic disease. Signal intensity ranged from normal (n = 3) to floridly increased in all muscle compartments (n = 17). Muscle and fascial involvement were not associated with clinical outcome. Controlling for duration of symptoms, the adjusted odds of progressing to chronic disease were higher for patients with abnormal subcutaneous fat signal than for those with normal fat signal (odds ratio, 9.0; 95% CI, 1.5-53.5; p < 0.02). CONCLUSION: MRI findings of muscle or fascia involvement do not predict clinical outcome in children with newly diagnosed JDMS. Abnormal subcutaneous fat signal appears to have a significant association with a more aggressive chronic disease course.

MR findings of synovial disease in children and young adults: Part 2.

Synovium is the thin membranous lining of a joint. It produces synovial fluid, which lubricates and nourishes the cartilage and bone in the joint capsule. Synovial diseases in children can be classified as normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts), noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), infectious synovial proliferation (pyogenic arthritis, tuberculous arthritis), deposition disease (gouty arthropathy), vascular malformation, malignancy (metastasis) and intra-/periarticular cysts and cyst-like structures. Other intra-articular neoplasms, such as intra-articular synovial sarcoma, can mimic synovial disease in children.

MR findings of synovial disease in children and young adults: Part 1.

Synovial diseases in children can be classified into normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts); noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), and infectious synovial proliferation, deposition disease, vascular malformations, malignancy (including metastasis) and intra-articular/periarticular cysts and cyst-like structures (ganglia). Familiarity with characteristic MR imaging findings of synovial diseases in children and young adults will enable a more confident diagnosis for earlier intervention and directed therapy. The first part of this paper will cover potential pathology of normal synovial structures as well as noninfectious synovial proliferation.

MR findings of primary bone lymphoma in a 15-year-old girl: emphasis on diffusion-weighted imaging.

We report a case of primary bone lymphoma (PBL) in a 15-year-old girl assessed by MR imaging with diffusion-weighted imaging (DWI). DWI has been shown to help characterize the cellularity of solid tumors and this case correlates well with previous data.

Medial collateral ligament of the knee on magnetic resonance imaging: does the site of the femoral origin change at different patient ages in children and young adults?

BACKGROUND: The medial patellofemoral ligament (MPFL), a chief medial restraint preventing lateral patellar dislocation, often is reconstructed in children with recurrent dislocation. The femoral MPFL attachment can be difficult to delineate at surgery. Therefore, the origin of the medial collateral ligament (MCL) frequently is used to approximate the reattachment site. The purpose of our study was to compile normative data from MR imaging examinations over different patient ages, to determine the effect of growth on the relationship of the MCL origin site to the distal femoral physis and medial femoral condyle (MFC). SUBJECTS AND METHODS: This HIPAA-compliant study was IRB approved. Informed consent requirement was waived. Three hundred knee MR imaging examinations (143 boys, 157 girls, 0-20 y) were evaluated. MCL origin to femoral physis distance, MFC height, and MCL origin-physis distance: MFC height ratio (MCL:MFC ratio) were calculated. Relationships between these values and age, gender, and physeal patency were assessed using linear regression models. RESULTS: With physeal patency, MCL origin-physis distance was significantly associated with increasing age in boys (P=0.0394), and trended toward significance in girls (P=0.0557). Distance increased 0.01 cm/y in both genders. MFC height increased 0.15 cm/y in boys and 0.13 cm/y in girls (P<0.0001). MCL:MFC ratio decreased 0.01/y (P<0.0001). With physeal closure, no significant change was measured for any variable. CONCLUSIONS: During growth, there are statistically significant, albeit minimal, changes of the MCL origin-physis distance and MFC height. As these changes are essentially negligible, no adjustment for age is needed during restorative MPFL surgery in growing children. CLINICAL RELEVANCE: As there is neglible change in location of the origin of the MCL relative to the distal femoral physis during skeletal growth in both boys and girls, no adjustment for patient age is necessary when using the origin of the MCL as a landmark to locate the site of femoral reattachment of a disrupted MPFL.

Cross-sectional imaging of pediatric biliary disorders.

The liver is the largest organ in the abdomen taking up a relatively greater area in infants and young children. It is a unique organ with a dual blood supply and amazing regenerative capacity. The liver has a number of important functions with regard metabolism, detoxification, and immune function. The internal anatomy of this organ is orderly and highly structured around the basic functional unit--the hepatic lobule and portal triad. Numerous pathologic conditions can involve the liver. In this article, we will focus on etiologic, clinical, and cross-sectional imaging features of several childhood congenital and acquired disorders of one component of the portal triad--the biliary system.

Bare spot of the glenoid fossa in children: incidence and MRI features.

BACKGROUND: The bare spot of the glenoid fossa is a normal cartilage defect seen frequently in adults. It has been used on arthroscopy as a landmark for the center of the glenoid fossa. There are no reports of this variant in children, but we have noted it on some pediatric clinical shoulder MRI studies. OBJECTIVE: Our main purpose is to evaluate the incidence of the bare spot in children and define location and MRI features. MATERIALS AND METHODS: Shoulder MRI studies (total 570) from 2004 to 2008 were reviewed. Children were divided into two age groups: group 1, 0-10 years (n = 200), group 2, 11-20 years (n = 370). RESULTS: A total of 12 bare spots (2.1%) were identified; all were seen in group 2. Eight (67%) were central and four were eccentric in the glenoid fossa. All showed a well-marginated focal cartilage defect containing hyperintense joint fluid or contrast agent. Three also had air. CONCLUSION: The bare spot is seen in children. The absence in children younger than 10 years and the low incidence in the second decade support the proposed acquired nature. Familiarity with this finding is important so as not to misinterpret it as a pathologic condition.

MR imaging in congenital and acquired disorders of the pediatric upper extremity.

Various congenital and acquired disorders can affect the upper extremity in pediatric and adolescent patients. MR imaging can provide unique anatomic and diagnostic information in the evaluation of many of these disorders, including inflammatory, infectious, neoplastic, and arthritic conditions. This article rounds out the issue on pediatric musculoskeletal MR imaging. It focuses on the evaluation of more common congenital disorders, and mainly sports-related injuries of the shoulder, elbow, and wrist in children. MR imaging can be more challenging in diagnosis of some of these disorders. Features of overuse injuries in skeletally immature athletes are a unifying theme throughout the article.

The healing potential of stable juvenile osteochondritis dissecans knee lesions.

BACKGROUND: The purpose of the present study was to determine if patient age, lesion size, lesion location, presenting knee symptoms, and sex predict the healing status after six months of a standard protocol of nonoperative treatment for stable juvenile osteochondritis dissecans of the knee. METHODS: Forty-two skeletally immature patients (forty-seven knees) who presented with a stable osteochondritis dissecans lesion were included in the present study. All patients were managed with temporary immobilization followed by knee bracing and activity restriction. The primary outcome measure of progressive lesion reossification was determined from serial radiographs every six weeks, for up to six months of nonoperative treatment. A multivariable logistic regression model was used to determine potential predictors of healing status from the listed independent variables. RESULTS: After six months of nonoperative treatment, sixteen (34%) of forty-seven stable lesions had failed to progress toward healing. The mean surface area (and standard deviation) of the lesions that showed progression toward healing (208.7 +/- 135.4 mm(2)) was significantly smaller than that of the lesions that failed to show progression toward healing (288.0 +/- 102.6 mm(2)) (p = 0.05). A logistic regression model that included patient age, normalized lesion size (relative to the femoral condyle), and presenting symptoms (giving-way, swelling, locking, or clicking) was predictive of healing status. Age was not a significant contributor to the predictive model (p = 0.25). CONCLUSIONS: In two-thirds of immature patients, six months of nonoperative treatment that includes activity modification and immobilization results in progressive healing of stable osteochondritis dissecans lesions. Lesions with an increased size and associated swelling and/or mechanical symptoms at presentation are less likely to heal.

Postoperative pelvic MRI of anorectal malformations.

OBJECTIVE: Patients operated on for anorectal malformations can experience technical complications related to the initial corrective surgery. Many of these complications may necessitate reoperation. Pelvic MRI is part of the evaluation to assess the position of the pulled-through bowel, the sphincter muscles, and the critical area of the posterior urethra. This article reviews the various pelvic MRI findings in these patients. CONCLUSION: Pelvic MRI is a valuable tool in the assessment of postoperative anorectal malformations that may necessitate additional surgery.

MRI appearance of chronic stress injury of the iliac crest apophysis in adolescent athletes.

OBJECTIVE: The objective of our study was to describe the MRI appearance of chronic repetitive stress injury of the iliac crest apophysis in adolescent athletes. CONCLUSION: Increased signal intensity on water-sensitive sequences and mild widening of the physis, often with adjacent bone marrow and muscle edema, are characteristic of chronic stress injury of the iliac apophysis in adolescent athletes who may present with hip, pelvic, or back pain.