Faculty Bibliography

OBJECTIVE:Injuries at the calcaneocuboid and talonavicular joint have been described as two distinct, unrelated entities in the radiology literature. Our purpose was to assess the coexistence of these injuries using radiography and MRI and to correlate our findings with radiologic and clinical diagnoses. MATERIALS AND METHODS/METHODS:Twenty-one patients with injury at the anterior calcaneal process on radiographs or MR images were retrospectively assessed for concomitant injury at the talonavicular joint. Radiologic and clinical diagnoses and treatment were documented. McNemar and kappa statistics were calculated; p values < 0.05 were considered statistically significant. RESULTS:Radiographic and MRI rates of detection of injuries across the Chopart joint were statistically different. Calcaneocuboid avulsion fractures were evident on 48% of radiographs and 100% of MR images (p = 0.001). Talonavicular joint injuries were evident on 38% of radiographs and 76% of MR images (p = 0.008). Concomitant injury at both joints was evident on 14% of radiographs and 76% of MR images (p < 0.0001). Interrater agreement was 0.488-0.637 and 0.286-0.364 for talonavicular and 0.144-0.538 and 0.976-1 for calcaneocuboid injuries on radiography and MRI, respectively. Sixty percent of calcaneocuboid fractures were prospectively missed on radiography (none on MRI), whereas 38% and 25% of talonavicular findings were missed on radiography and MRI, respectively. Sixty percent of injuries were clinically misdiagnosed as ankle sprains. Chopart joint injury was never mentioned in prospective clinical or imaging diagnoses. CONCLUSION/CONCLUSIONS:Calcaneocuboid and talonavicular injuries commonly coexist. Radiographs underestimate severity of injury; MR images show more subtle abnormalities. Lack of mention of Chopart joint injury clinically and on imaging reports underlies the need for greater familiarity with this entity.

OBJECTIVE: This study determined the frequency and MRI appearance of osseous and ligamentous injuries in midtarsal (Chopart) sprains and their association with ankle sprains after acute ankle injuries. Prospective diagnosis of and interobserver agreement regarding midtarsal injury among musculoskeletal radiologists were also assessed. SUBJECTS AND METHODS: Two cohorts with ankle MRIs were identified via a digital PACS search: patients who had undergone MRI within 8 weeks after ankle injury and control subjects who had not sustained ankle trauma. Studies were retrospectively reviewed in consensus as well as independently, assessing ligamentous and osseous injury to the Chopart joint (calcaneocuboid and talonavicular joints) and associated lateral collateral and deltoid ligamentous injury. Interobserver agreement was calculated, and prospective radiology reports were reviewed to determine the musculoskeletal radiologist's familiarity with Chopart joint injury. RESULTS: MR images of control subjects (n = 16) and patients with ankle injury (n = 47) were reviewed. The normal dorsal calcaneocuboid and calcaneocuboid component of bifurcate ligaments were variably visualized; the remaining normal ligaments were always seen. Eleven patients (23%) had midtarsal ligamentous and osseous injury consistent with midtarsal sprain (eight acute or subacute, one probable, and two old). Six (75%) of eight acute or subacute cases had coexisting lateral collateral ligament injury. Eighty-nine percent of osseous injuries were reported prospectively, but 83% of ligamentous injuries were missed. Substantial interobserver agreement was achieved regarding diagnosis of midtarsal sprain. CONCLUSION: Midtarsal sprains are commonly associated with acute ankle injury and with ankle sprains. Presently, midtarsal sprains may be underrecognized by radiologists; thus, greater familiarity with the MRI spectrum of ligamentous and osseous injuries at the Chopart joint is important for accurate diagnosis and clinical management.

PURPOSE: To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. MATERIALS AND METHODS: One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015-1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. RESULTS: Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0-99.5%), with no excess disagreement (/= 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p < 0.001). Sensitivities (59-100%) and specificities (73-99%) of fast and standard MRI were not significantly different for meniscal and ligament tears (95% CI for difference, -0.08-0.08). For cartilage defects, fast MRI was slightly less sensitive (95% CI for difference, -0.125 to -0.01) but slightly more specific (95% CI for difference, 0.01-0.5) than standard MRI. CONCLUSION: A fast 5-min MRI protocol is interchangeable with and has similar accuracy to a standard knee MRI for evaluating internal derangement of the knee.

OBJECTIVE: The bare spot (BaS) is a central, well-circumscribed focal defect in the glenoid articular surface, with reported adult incidence of 1-2%. We aimed to reassess MRI features of BaS in the pediatric population and determine its etiology. MATERIALS AND METHODS: A retrospective search of our database from June 2014 to October 2015 was performed for shoulder MRI in patients between 5 and 25 years and then subdivided into four groups: group 1, 5-10 years; group 2, 10-15 years; group 3, 15-18 years; group 4, 20-25 years. BaS was defined as a well-marginated, central defect of increased signal in the articular surface of the glenoid, seen on at least two planes, without evidence of underlying glenoid pathology. Presence, location and size along with clinical indications were documented. RESULTS: A final cohort of 253 patients revealed 23 BaS, 3.5% in group 1, 20% in group 2, 5% in group 3 and 4% in group 4. There was a significantly higher incidence in group 2 (p = 0.007) compared to group 3 and p = 0.002 compared to group 4. Location was mainly central. Mean size was significantly bigger in group 2 compared to group 3 and 4. Distribution showed the highest number at 14-15 years of age. Instability was higher in groups 3 and 4. CONCLUSION: Incidence of BaS in group 2 was significantly higher than in other age groups and higher than in adults. BaS was also larger compared to other populations. These findings support a developmental theory, explained by the centripetal ossification of the glenoid.

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: 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

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: 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

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.