Faculty Bibliography

OBJECTIVE: To evaluate the position of the peroneus longus (PL) tendon relative to the cuboid tuberosity and cuboid tunnel during ankle dorsiflexion and plantarflexion using ultrasound and MRI. MATERIALS AND METHODS: The study population included two groups: 20 feet of 10 asymptomatic volunteers who underwent prospective dynamic ultrasound and 55 ankles found through retrospective review of routine ankle MRI examinations. The location of the PL tendon at the cuboid tuberosity and cuboid tunnel was designated as completely within the tunnel, indeterminate, or subluxed with respect to ankle dorsiflexion and plantarflexion. RESULTS: On dynamic ultrasound, the PL tendon was perched plantar to the cuboid tuberosity in dorsiflexion, and glided to enter the cuboid tunnel distal to the tuberosity in plantarflexion in all 20 feet. On the MRI evaluation, there was a statistically significant difference (p = 0.0006) in the location of the PL tendon between the ankles scanned in dorsiflexion and plantarflexion. CONCLUSION: Based on our findings on ultrasound and MRI, the PL tendon can glide in and out of the cuboid tunnel along the cuboid tuberosity depending on ankle position. Thus, "subluxation" of the tendon as it curves to enter the cuboid tunnel, which to the best of our knowledge has not yet been described, should be recognized as a normal, position-dependent phenomenon and not be reported as pathology.

Osteonecrosis of the hip (Legg-Calve-Perthes) is a common disease, with 10,000-20,000 symptomatic cases annually in the United States. The disorder affects both adults and children and is most frequently associated with trauma and corticosteroid usage. The initial imaging evaluation of suspected hip osteonecrosis is done using radiography. MRI is the most sensitive and specific imaging modality for diagnosis of osteonecrosis of the hip. The clinical significance of hip osteonecrosis is dependent on its potential for articular collapse. The likelihood of articular collapse is significantly increased with involvement of greater than 30%-50% of the femoral head area, which is optimally evaluated by MRI, often in the sagittal plane. Contrast-enhanced MRI may be needed to detect early osteonecrosis of the hip in pediatric patients, revealing hypoperfusion. In patients with a contraindication for MRI, use of either CT or bone scintigraphy with SPECT (single-photon emission CT) are alternative radiologic methods of assessment. Imaging helps guide treatment, which may include core decompression, osteotomy, and ultimately, need for joint replacement. The ACR Appropriateness Criteria((R)) are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Purpose: Assess, utilizing MRI, the normal maturation and stress injury to the coracoid process and bipolar growth plate, at the interface with the underlying scapula. To the best of our knowledge this has not yet been described in the literature. Materials and Methods: The study was divided into 2 parts: (A) Maturation of the coracoid process and bipolar growth plate. Retrospective review of 182 consecutive shoulder MRIs in 160 children without clinical or MRI evidence of coracoid pathology (107 boys, 53 girls, ages 0 to <5, n=36, 5 to <10, n = 25, 10 to <15, n = 67, and 15 to 18, n = 54). The studies were reviewed with special attention to the development and fusion of the coracoid to the scapula, via the bipolar growth plate. (B) Growth plate injuries. Retrospective review of shoulder MRIs with coracoid growth plate disturbance (7 boys, 1 girl, mean age 15). Results: (A)Maturation of the coracoid process and bipolar growth plate. At 0 to <5 years the cartilaginous coracoid precursor conformed to the shape of a mature coracoid process, with a small oval primary ossification center within it. The bony margins at the coracoid-scapular interface transformed from smooth to irregular with advancing age. At 5 to <10 years of age, a more distinct, undulating, bipolar growth plate developed. Complete closure of the bipolar plate was observed as early as 11 years of age and was noted in 41 % of patients by age 14 and in 86 % of 15 to 18 year olds. (B) Growth plate injuries. The 8 patients with growth plate stress injuries included 2 patients with neuromuscular disorders and 6 patients with sports related symptoms. The growth plate demonstrated widening, irregularity, and increased signal, with surrounding soft tissue and opposing bony marrow edema and hypertrophy. Conclusion: MRimaging of normal maturation as well as stress injury of the base of the coracoid is crucial for accurate imaging diagnosis. Injury to the base of the coracoid, while uncommon, should be considered when assessing adolescents with shoulder symptomatology

Purpose: The bare area (BA) is a central, well-circumscribed focal defect in the articular surface of the glenoid, with reported adult incidence of 1- 2 %. The adult literature supports a developmental etiology, however, a recent imaging study, based on a pediatric patient population, suggested a similar incidence of BA but advocated a traumatic origin. The purpose of our study was to reassess the prevalence and MRI appearance of the glenoid bare area in the pediatric population. Materials and Methods: Retrospective review of our digital database from 6/2014 to 10/2015 identified 150 shoulderMRI in children between 10 and 18 years of age. The patients were divided into 2 age groups: group 1, 10-15 years (n = 75) and group 2, 15-18 years (n=75). The bare area was defined as a well marginated, central defect, of increased signal in the articular surface of the glenoid, seen on at least 2 imaging planes, without evidence of underlying glenoid pathology. The presence, location and size of the BAwere documented in each group. Results: A total of 19 BA were identified, 15 (20 %) in group 1 and 4 (5 %) in group 2, with a significantly higher incidence in the younger group (p = 0.007, Chi Square Test). Location was mainly central (12 (80 %) in group 1, 3 (75 %) in group 2). The mean size was 3.44 mm, range, 1.5-7.5 mm in group 1; mean size of 2.47 mm, range, 1.6-3.2 mm in group 2. Conclusion: The incidence of the BA in children ranging from 10 to 15 years of age is significantly higher than in older children and higher than the reported incidence in adults. The BA is also larger in the younger compared to the older pediatric age group. Our findings may be explained by the centripetal pattern of ossification of the glenoid and, thus, give support to the normal developmental theory. Familiarity with the MR appearance of the BA should obviate misinterpreting as a pathologic condition in the pediatric patient population

Purpose: Medial hindfoot coalitions, particularly posterior extra-articular and overlap coalitions, may have large medial and posteromedial osseous excrescences which extend into and produce, in conjunction with flat foot deformity, stretching and mass effect on the tarsal tunnel. Resection of the coalition without addressing pathology of these soft tissue structures can result in surgical failure and continued disability to the patient. Yet, to the best of our knowledge, there is scant information about this topic in the literature. We hypothesize that soft tissue disease in the tarsal tunnel is a frequent phenomenon, in the setting of hindfoot coalitions. Materials and Methods: A search of our ankle MRI data base revealed 88 cases with medial hindfoot coalitions. All cases were independently and retrospectively reviewed by 2 musculoskeletal radiologists for the presence of neuritis, manifested by focally increased nerve caliber and signal, of the posterior tibial nerve and its medial and lateral plantar branches. The posterior tibial (PT), flexor hallucis longus (FHL) and flexor digitorum longus (FDL) were assessed for the presence of tendinosis, tenosynovitis and partial tearing. Results: The final cohort included 68 cases of medial hindfoot (middle, posterior extra-articular and overlap) coalition (37 men, 31 women, average age 40, range 72-8). Neuritis of the posterior tibial nerve and its branches (n = 18, 26 %) was more commonly noted in the medial plantar nerve. Entrapment of FHL by osseous coalition-related posteromedial excrescences was seen in 14 cases (21 %). Other tendon disorders such as flattening and stretching against sharp bony edges, tendinosis, partial tearing and tenosynovitis were noted in the FHL (n = 30, 44 %) and FDL (n = 22, 32 %). PT tendinosis and tearing was less common (n=9, 13%). Conclusion: Medial hindfoot coalitions are commonly associated with tarsal tunnel soft tissue abnormalities affecting the posterior tibial nerve and its branches, the FHL tendon and less commonly FDL and PT tendons. The radiologist should alert the referring physician for the presence of tarsal tunnel abnormalities in the presence of medial hindfoot coalition since these can guide surgical treatment and outcome