Faculty Bibliography

PURPOSE: To assess the MRI features of growth plate injury at the base of the coracoid process. MATERIALS AND METHODS: Subjects were identified through retrospective search of our department imaging database and teaching files and the teaching files of two outside academic institutions. The coracoid base growth plate was examined with attention to widening, irregularity, abnormal signal intensity of the growth plate, and the presence of adjacent soft tissue edema. The apposing coracoid and scapular bony surfaces were examined for signal intensity and morphology. RESULTS: Shoulder MRIs in eight patients with coracoid base growth plate disturbances were retrospectively reviewed (7 males, 1 female, mean age 15 years). Growth plate injury manifested as widening, irregularity and increased signal, apposing bony marrow edema and hypertrophy, and surrounding soft tissue edema. Five subjects were athletes (football, archery, basketball, swimming, rugby), two had a history of neuromuscular disorders, and one subject presented after a fall. Clinical indications included: rule out labral tear (n = 3), rule out rotator cuff tear or fracture after fall (n = 1), nonspecific pain (n = 1), shoulder subluxation, rule out glenoid pathology (n = 1, patient with underlying neuromuscular disorder), muscular dystrophy with shoulder pain (n = 1), and impingement (n = 1). Coracoid growth plate injury was not suspected clinically in any of the patients. CONCLUSION: Awareness of the imaging appearance of coracoid base growth plate injury can aid in a more accurate diagnosis of shoulder MRI studies in young pediatric athletes. While uncommon, coracoid growth plate injury should be considered when assessing children with shoulder symptomatology.

Purpose: Talocalcaneal coalition and medial ankle accessory muscles can both predispose to tarsal tunnel syndrome due to stretching and extrinsic compression of the posterior tibial nerve and its branches in the tarsal tunnel. We have anecdotally observed a high proportion of medial accessory ankle muscles in patients with talocalcaneal coalitions. The purpose of our study was to assess this previously unrecognized association with the hypothesis that this may be an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition. Materials and Methods: A search of our department imaging database, utilizing the keyword "coalition" yielded 79 cases. Images were retrospectively reviewed by two musculoskeletal (MSK) radiologists for the presence of medial ankle accessory muscles, including: accessory soleus, accessory flexor digitorum longus, and peroneocalcaneus internus. In addition, 30 cases, selected from the final cohort, were reviewed independently by two (MSK) readers to determine interobserver agreement utilizing the kappa coefficient. Results: The final cohort included 67 ankle MRIs in 65 patients, part of a cohort previously published describing the association of talocalcaneal coalitions and soft tissue pathology in the tarsal tunnel, (35 men, 30 women, age range 8-72 years, mean age, 40 years). Overall n = 14 (21%) of patients with talocalcaneal coalition had a medial sided accessory muscle, including accessory flexor digitorum longus muscle in 8 ankles (12% compared to 2-8% reported in the general population), a peroneocalcaneus internus in 4 ankles (6% compared to 1% reported in the general population) and an accessory soleus in 2 ankles (3% compared to 0.7-5.5% of the general population). The kappa coefficient was calculated as 0.61, demonstrating substantial agreement among readers in detecting medial accessory muscles. Conclusion: Medial sided accessory ankle muscles are more common in patients with talocalcaneal coalitions compared to the general population, with the most common muscle being the accessory flexor digitorum longus. It is important for radiologists to be aware of medial accessory muscles as an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition, a cohort already predisposed to compression of soft tissue structures by coalition related bony excrescences and hindfoot valgus deformity

Purpose: Quantification of tendon retraction is paramount in the surgical decision-making algorithm for proximal hamstring avulsion injury. Not only is it used to determine if surgery is indicated, but it may lead the surgeon to change the pre-operative plan from a more aesthetically-appealing gluteal fold incision to a more extensile, longitudinally-based proximal thigh incision. However, the hamstring origin on the ischial tuberosity is broad. Variability in location on the ischial tuberosity used as the proximal landmark and occasional difficulty in locating the proximal tendon stump may lead to differences in perceived retraction, altering the surgical decision making process. We hypothesize there will be substantial variability in the ischial tuberosity location used as the proximal marker, not only between orthopaedists and radiologists, but also amongst radiologists themselves. Materials and Methods: Two surveys were created for the purpose of this study. One survey was sent to members of the Society of Skeletal Radiology (SSR), querying the preferred ischial tuberosity landmark, perceived difficulties in quantifying retraction, and the impact of radiology measurements on clinical decision making. A similar survey, with added questions on the impact of imaging findings in clinical management was approved and posted onto the American Orthopaedic Society for Sports Medicine (AOSSM) website. Results: Two hundred and fifteen SSR members responded to the survey. For cases of complete and partial hamstring avulsion, there was variability among musculoskeletal (MSK) radiologists in the proximal landmark used for quantification of retraction, with n = 100 (47%) using the conjoint tendon origin, n = 84 (39%) using the semimembranosus tendon origin, and n = 31(14%) using the posterior-inferior edge of the ischial tuberosity. Difficulty in determining location of the retracted tendon stump was reported by n = 93(44%) of MSK radiologists. Most MSK radiologists (n = 118, 55%) reported measurements in their dictation and were unsure as to whether or not they are used to guide clinical management. Results of the second survey posted by AOSSM will be subsequently reported when available. Conclusion: Differences in choosing an ischial tuberosity landmark and occasional difficulty in locating the proximal tendon stump may lead to substantial variability in measured tendon retraction among MSK radiologists in cases of proximal hamstring avulsion. Radiologists should consider a standardized approach to measuring tendon retraction or should clearly stipulate the location of the proximal landmark in their reports

Purpose: Determine the frequency and pattern of Chopart joint injury in acute ankle injuries and assess familiarity of the interpreting radiologists with this injury. To the best of our knowledge this clinically difficult diagnosis has barely been reported in the radiology literature, yet may be important for diagnosis and treatment of calcaneocuboid joint instability. Materials and Methods: Normal Chopart joint: 25 MRIs in 25 patients without clinical or MRI evidence of ankle ligamentous pathology were reviewed to establish normal MRI appearance of the calcanocuboid and talonavicular joints, with attention to the dorsal calcaneocuboid, bifurcate, spring, short and long plantar, and talonavicular ligaments. Chopart joint injury: A digital search for ankle MRIs obtained within 8 weeks of clinical history of acute ankle injury was performed (2/2014-8/2016). The studies were retrospectively reviewed for ligamentous and osseous pathology at Chopart joint. Other relevant findings were recorded: Lateral collateral ligament injury, plantar talar marrow edema, and extensor digitorum brevis (E

Purpose: The purpose of this study was to determine if a 5-minute knee magnetic resonance imaging (MRI) protocol is interchangeable with a standard knee MRI protocol for evaluation of internal derangement of the knee. Materials and Methods: 100 consecutive patients, in whom a knee MRI was performed for internal derangement between January 2015 and June 2015, were retrospectively reviewed. All patients were scanned on a single 3 T MRI system (Siemens Verio) with a 15- channel knee coil (Siemens). The standard clinical protocol consisting of 6 2-dimensional fast spin echo (2D FSE) sequences without parallel imaging was performed along with 5 additional fast 2D FSE sequences with parallel imaging (acceleration factor = 2). 3 readers (2 musculoskeletal (MSK) radiologists and 1 MSK radiology fellow) independently reviewed the fast and standard images which were anonymized and separated into 2 different reading sets. Readers evaluated for the presence of meniscal and ligament tears, cartilage defects, and bone abnormalities. Frequency of major findings was measured. Interchangeability of fast and standard MRI was tested by comparing the agreement when 1 reader was using fast MRI and the other reader was using standard MRI (interprotocol agreement) with the agreement when both readers were using the standard MRI (intraprotocol agreement). Fast MRI was considered interchangeable if the interprotocol agreement was not less < 5% of the intraprotocol agreement. Results: The study population consisted of 69 males and 31 females with a mean age of 38.8 years (range 18 - 65). The average time for the fast protocol was 4 minutes 8 seconds compared to 17 minutes 20 seconds for the standard protocol. The most common findings reported on MRI as an aggregate of all readers was as follows: medial meniscal tears (46.7%), high grade partial thickness or full thickness cartilage defects (21.9%), lateral meniscal tears (21.3%), and ACL tears (15.7%). The intraprotocol agreement was very similar to the interprotocol agreement for all structures. The intraprotocol and interprotocol agreement were as follows for individual structures, respectively: Medial Mensicus (89.3% vs. 90.0%); Lateral Meniscus (89.3% vs. 89.0%); ACL (96.0% vs. 95.7%); PCL (98.0% vs. 98.3%); MCL (98.0% vs. 98.3%); LCL (98.7% vs. 98.2%); Cartilage (86.3% vs. 86.2%); Fracture/Contusion (90.7% vs. 93.0%); and Marrow Disease (98.0% vs. 98.0%) . The upper bounds of the 95% CIs for the differences between these two proportions were always <5%, suggesting that fast knee MRI can be interchanged with standard MRI without a significant increase in disagreements between readers. Conclusion: A 5-minute knee MRI consisting of multiplanar 2D FSE sequences using parallel imaging is interchangeable with a standard knee MRI for evaluating internal derangement of the knee

OBJECTIVE: To describe the post-surgical imaging appearance and complications of high tibial osteotomy in patients with the iBalance implant system (iHTO; Arthrex, Naples, FL, USA). MATERIALS AND METHODS: Retrospective, institutional review board-approved, Health Insurance Portability and Accountability Act-compliant review of imaging after 24 iBalance procedures was performed with attention to: correction of varus malalignment, healing at the osteotomy site, resorption of the osteoinductive compound, and complications. RESULTS: Immediate correction of the varus deformity was present in all cases. Lobular radiolucency was present in all cases, more pronounced on the lateral knee radiograph, simulating infection or erosive disease. Four radiographic signs of healing were observed: blurring at the opposing osteotomy bony margins and at the osteoinductive compound and the adjacent bone interface, callus formation, and resorption of the osteoinductive compound. Complications were present in 33 % of cases, including fracture through the lateral tibial cortex (21 %), genu varum recurrence (8 %), painful exuberant bone formation (4 %), persistent pain, requiring total knee arthroplasty (4 %), and non-union (after >6 months' follow-up), with suspected infection (4 %). CONCLUSION: Radiologists should be aware of the normal radiographic appearance following iBalance high tibial osteotomy, which may be confused with infection. Radiologists should also be aware of potential post-operative complications and compare all post-operative radiographs with the immediate post-operative examination to detect collapse of the osteotomy site and recurrence of varus angulation.

OBJECTIVE: To assess, utilizing MRI, tarsal tunnel disease in patients with talocalcaneal coalitions. To the best of our knowledge, this has only anecdotally been described before. MATERIALS AND METHODS: Sixty-seven ankle MRIs with talocalcaneal coalition were retrospectively reviewed for disease of tendons and nerves of the tarsal tunnel. Interobserver variability in diagnosing tendon disease was performed in 30 of the 67 cases. Tarsal tunnel nerves were also evaluated in a control group of 20 consecutive ankle MRIs. RESULTS: Entrapment of the flexor hallucis longus tendon (FHL) by osseous excrescences was seen in 14 of 67 cases (21 %). Attenuation, split tearing, tenosynovitis, or tendinosis of the FHL was present in 26 cases (39 %). Attenuation or tenosynovitis was seen in the flexor digitorum longus tendon (FDL) in 18 cases (27 %). Tenosynovitis or split tearing of the posterior tibial tendon (PT) was present in nine cases (13 %). Interobserver variability ranged from 100 % to slight depending on the tendon and type of disease. Intense increased signal and caliber of the medial plantar nerve (MPN), indicative of neuritis, was seen in 6 of the 67 cases (9 %). Mildly increased T2 signal of the MPN was seen in 15 (22 %) and in 14 (70 %) of the control group. CONCLUSIONS: Talocalcaneal coalitions may be associated with tarsal tunnel soft tissue abnormalities affecting, in decreasing order, the FHL, FDL, and PT tendons, as well as the MPN. This information should be provided to the referring physician in order to guide treatment and improve post-surgical outcome.

Purpose: Examine the accuracy of diagnosing adhesive capsulitis (AC) on MRI, using physical exam and clinical impression of an orthopedic sports clinician as the diagnostic reference standard. Materials and Methods: Retrospective query of our digital database was performed to identify all shoulder MRIs performed at our institution in 2013. The first 100 consecutive subjects aged >40 were included for further review. MRI reports were assessed for the presence of the following information: 1. Thickening of the capsule at the axillary recess (AR), 2. Thickening of the coracohumeral ligament (CHL), 3. Infiltration/ edema of subcoracoid fat, 4. Disproportionate fluid within the proximal biceps tendon sheath, and 5. Imaging impression ofAC. Orthopedic notes were assessed for documented range of shoulder motion and overall clinical impression (10 sports fellowship-trained orthopedic surgeons, 1 shoulder and elbow fellowship-trained orthopedic surgeon, and 1 sports medicine trained primary care physician). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy were calculated. Fisher exact tests were performed to determine whether each imaging finding was predictive of a positive clinical diagnosis of AC, or likely to predispose to a false positive diagnosis of AC. Results: One hundred shoulder MRI reports in 99 patients were analyzed (59men, 40 women;mean age 58, range 40-87). 17 patients were diagnosed with AC based on imaging findings. Of these patients, frequency of imaging findings included: thickening of the AR (11) or the CHL (8), infiltration of subcoracoid fat (13), and disproportionate fluid in the proximal biceps tendon sheath (3). Six patients had a clinical diagnosis of AC. Fifteen MRIs demonstrated false positive results, while false negative results were seen in 4 cases. The overall sensitivity for theMRI diagnosis of AC was 33.3%with a specificity of 84%. The PPV was 11.8 %,NPV 95.2 %, and overall accuracy 81 %. Fisher exact test P values to determine whether each imaging finding was predictive of a reference standard diagnosis of AC ranged from 0.109 to 1.000. P values to determine whether each imaging finding would lead to a false positive MRI diagnosis were <0.001 for subcoracoid fat infiltration, thickening of the AR, and thickening of the CHL, and p = 1.000 for disproportionate fluid in the biceps tendon sheath. Conclusion: The predictive value of the established MRI findings of adhesive capsulitis may not be as strong as previously shown. Radiologists should be aware of potential imaging over diagnosis and should correlate imaging findings with documented physical exam, when available

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: 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