The Accuracy of 3D Printed Carpal Bones Generated from Cadaveric Specimens.

BACKGROUND: Computer assisted three-dimensional (3D) printing of anatomic models using advanced imaging has wide applications within orthopaedics. The purpose of this study is to evaluate the 3D printing accuracy of carpal bones. METHODS: Seven cadaveric wrists underwent CT scanning, after which select carpal bones (scaphoid, capitate, lunate, and trapezium) were dissected in toto. Dimensions including length, circumference, and volume were measured directly from the cadaver bones. The CT images were converted into 3D printable stereolithography (STL) files. The STL files were converted into solid prints using a commercially available 3D printer. The 3D printed models' dimensions were measured and compared to those of the cadaver bones. A paired t-test was performed to determine if a statistically significant difference existed between the mean measurements of the cadavers and 3D printed models. The intraclass correlation coefficients (ICC) between the two groups were calculated to measure the degree of agreement. RESULTS: On average, the length and circumference of the 3D printed models were within 2.3 mm and 2.2 mm, respectively, of the cadaveric bones. There was a larger discrepancy in the volume measured, which on average was within 0.65 cc (15.9%) of the cadaveric bones. These differences were not statistically significant (P > 0.05). There was strong agreement between all measurements except the capitate's length and lunate's volume. CONCLUSION: 3D printing can add value to patient care and improve outcomes. This study demonstrates that 3D printing can both accurately and reproducibly fabricate boney models that closely resemble the corresponding cadaveric anatomy.

Primary leiomyosarcoma of the distal tibia: A case report.

The authors present an unusual case of a leiomyosarcoma of the distal tibia. Leiomyosarcoma tumors typically originate from smooth muscle tissue. It is rare for it to derive from bone and even rarer to be found in a bone of the lower limb. Given this extreme rarity in addition to nonspecific findings on plain film radiographs and magnetic resonance imaging (MRI), biopsy was needed in this case. It was only through immunochemistry staining that a definitive diagnosis was made. As such, this case is an illustrative example of an aggressive, though rare, primary lesion of the bone which should be considered in the differential diagnosis of a lytic intramedullary lesion. This case also highlights the need for careful evaluation of imaging features suggesting a potentially aggressive lesion requiring appropriate work up in a timely fashion.

Extra-articular synovial chondromatosis of the ankle: Unusual case with radiologic-pathologic correlation.

Extra-articular synovial chondromatosis is a rare entity in the foot and ankle. We present a case of a 49-year-old female who presented for evaluation of a palpable concern following trauma; which was found to represent synovial chondromatosis. This case demonstrates the multimodality imaging findings, including ultrasound and MRI, with histopathologic correlation.

ThoraSite: A device to improve accuracy of lateral decompression needle and chest tube placement.

BACKGROUND: Multiple reports have detailed an unacceptably high error rate in the siting of decompression needles and tubes and describe associated iatrogenic injuries. The objective of the current study was to measure the accuracy of the novel ThoraSite template for identifying an acceptable intercostal space (ICS) for lateral needle or tube thoracostomy. METHODS: Two trained operators used the ThoraSite to place radiopaque needles in the left and right lateral chests of 12 cadavers. An independent radiologist reviewed fluoroscopy images to determine the primary outcome: the ICS in which each needle was placed. Secondary outcomes were ICS's palpable through ThoraSite's Safe Zone; needle placement relative to the anterior axillary line (AAL) and midaxillary line (MAL); and percent correct placement (defined as the third, fourth, or fifth ICS from 1 cm anterior to the AAL to 1 cm posterior to the MAL). RESULTS: The six female and six male cadavers spanned 4 ft and 11 inches (150 cm) to 6 ft and 7 inches (201 cm), 80 lb (36 kg) to 350 lb (159 kg), and 16 kg/m to 42 kg/m body mass index. All 24 needles were placed in either the third (4 [17%] of 24 needles), fourth (10 [42%] of 24 needles), or fifth ICS (10 [42%] of 24 needles). In 10 (42%) of 24 assessments, two ICSs were palpable in ThoraSite's Safe Zone. All palpable ICSs were either the third (8 [24%] of 34), fourth (15 [44%] of 34); or fifth ICS (11 [32%] of 34). Twenty-three (96%) of 24 needles were inserted from 1 cm anterior to the AAL to 1 cm posterior to the MAL. Twenty-three (96%) of 24 needle placements were correct. CONCLUSION: ThoraSite use was associated with needle placement in the third, fourth, or fifth ICS in an area roughly spanning the AAL to MAL in anatomically diverse cadavers. By facilitating appropriate needle/tube placement, ThoraSite use may decrease iatrogenic injuries. Future study involving representative users may be useful to further evaluate ThoraSite accuracy. LEVEL OF EVIDENCE: Therapeutic and care management, level IV.

Flexor pollicis longus (FPL) tendon hypoplasia: A case report and literature review.

An 18-year-old female presented with long-standing inability to flex her left thumb. MRI of the left thumb revealed flexor pollicus longus (FPL) tendon hypoplasia, and subsequent ultrasound of the bilateral thumbs confirmed a left-sided hypoplastic FPL tendon. Structural integrity of the left FPL tendon was confirmed during surgical examination under anesthesia. Multiple congenital anomalies of the FPL have been described, but FPL tendon hypoplasia and its appearance on imaging are rarely reported. This case demonstrates the diagnosis of FPL tendon hypoplasia on MRI, ultrasound, and surgical examination under anesthesia; and demonstrates the importance of including this entity in the differential diagnosis for impaired thumb flexion.

Spontaneous Fracture of the Os Peroneum With Rupture of the Peroneus Longus Tendon.

Rupture of the peroneus longus tendon with or without an associated os peroneum fracture is rare and uncommonly encountered in the published data. Owing to the infrequent nature, a high index of suspicion is required. Otherwise, the opportunity for the injury to result in a delayed or missed diagnosis is increased. We report the case of a 39-year-old male with spontaneous rupture of the peroneus longus tendon and associated fracture of the os peroneum. The spontaneous rupture and fracture were diagnosed from the history, physical examination, and imaging findings. The patient elected to undergo operative repair, with excellent results, full recovery, and full return to normal function.

Resident Perspectives of an Interactive Case Review Following Independent Didactic Study as a Method of Teaching a Pediatric Imaging Curriculum.

PURPOSE: The ABR has recently changed the format of the board examination, in which the oral examination was replaced by a computer based multiple-choice test. The purpose of this study was to determine resident's perceptions of a new conference resembling the new ABR format. METHODS: Residents were requested to review a series of didactic pediatric imaging presentations prior to attending case conference. During conference, unknown cases reflecting the subject matter from the didactic presentations were presented along with multiple-choice questions. We then surveyed resident perspectives after each case conference. RESULTS: Between 14 and 18 residents were surveyed at the end of each subspecialty case review presentation. About 94% of resident respondents felt that the independent didactic study followed by an interactive case review session would better prepare them for the ABR certification exams, compared to didactic lectures alone. Furthermore, 95% of the respondents indicated that they preferred the independent didactic review followed by interactive case review versus didactic lecture alone. Most the respondents (85%) felt that combining independent didactic review with interactive unknown case sessions made the material more interesting and provided greater understanding of the material. There was no statistically significant difference in the distribution of answers across the subspecialty sessions (p > .05). CONCLUSION: Radiology residents favorably reviewed the combination of independent review of didactic material prior to interactive case review. Material presented in this fashion is felt to be more interesting and is thought to result in enhanced understanding of pediatric radiology material.

Limitations of radiographs in evaluating non-displaced osteochondral lesions of the talus.

OBJECTIVE: To evaluate what limitations, if any, radiographs have in detecting and characterizing the morphology of non-displaced OCLTs (size, cystic change, fragmentation, and avascular necrosis [AVN]). MATERIALS AND METHODS: Thirty-three OCLTs in 32 patients were reviewed in consensus by a board-certified, fellowship-trained musculoskeletal radiologist and orthopedic surgeon, on radiographs and MRI examinations performed within 15 days of one another. Location, dimensions, and characteristics of the OCLT (fragmentation, bone marrow edema, cystic change, and necrosis) were documented on the radiographs and MRI examinations. RESULTS: There was an average of 7.5 days (range: 1-15 days) between the MRIs and radiographs. Eighteen (55%) medial and 15 (45%) lateral OCLTs were found; none was displaced. OCLTs were categorized into three groups: Group 1-initially diagnosed with radiographs (4/33; 12%), Group 2-diagnosed with radiographs only after MRI correlation (20/33; 61%), and Group 3-not identifiable on radiographs despite MRI correlation (9/33; 27%). The dimensions of all of the lesions in Groups 1 and 2 were underestimated on radiographs. Only 1 of the 4 (25%) lesions in Group 1 and 1 of the 20 (5%) lesions in Group 2 could be measured in the anteroposterior (AP) dimension (using a lateral radiograph). The most common radiographic appearance of non-displaced OCLTs was an "ill-defined" lucency at the talar dome (20/33; 61%). Across all three groups, fragmentation, cystic change, and AVN were radiographically apparent in 3/10 (30%), 4/19 (21%), and 1/6 (17%) cases respectively. CONCLUSION: Compared with MRI, radiographs are limited in their evaluation of the size (particularly the AP dimension) and characteristics (fragmentation, cystic change, and AVN) of non-displaced OCLTs. The most common appearance of non-displaced OCLTs is an "ill-defined" lucency at the talar dome. When this appearance is also considered, the estimated retrospective sensitivity of radiographs improves considerably.

Clavicular avulsion of the costoclavicular (rhomboid) ligament: MRI findings.

Sprain of the costoclavicular (rhomboid) ligament is an uncommon but symptomatic traumatic injury. To date, there is no report of the MRI findings of isolated, traumatic, rhomboid ligament injury. We report a case of traumatic rhomboid ligament avulsion from the clavicular insertion diagnosed by MRI. Radiologists and treating physicians alike may find this information useful in their clinical practice.

Prediction of midfoot instability in the subtle Lisfranc injury. Comparison of magnetic resonance imaging with intraoperative findings.

BACKGROUND: The objective of the present study was to assess the utility of magnetic resonance imaging for the diagnosis of an injury to the Lisfranc and adjacent ligaments and to determine whether conventional magnetic resonance imaging is a reliable diagnostic tool, with manual stress radiographic evaluation with the patient under anesthesia and surgical findings being used as a reference standard. METHODS: Magnetic resonance images of twenty-one feet in twenty patients (ten women and ten men with a mean age of 33.6 years [range, twenty to fifty-six years]) were evaluated with regard to the integrity of the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal-metatarsal ligaments, and the medial-middle cuneiform ligament. Furthermore, the presence of fluid along the first metatarsal base and the presence of fractures also were evaluated. Radiographic observations were compared with intraoperative findings with respect to the stability of the Lisfranc joint, and logistic regression was used to find the best predictors of Lisfranc joint instability. RESULTS: Intraoperatively, seventeen unstable and four stable Lisfranc joints were identified. The strongest predictor of instability was disruption of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals (the pC1-M2M3 ligament), with a sensitivity, specificity, and positive predictive value of 94%, 75%, and 94%, respectively. Nineteen (90%) of the twenty-one Lisfranc joint complexes were correctly classified on magnetic resonance imaging; in one case an intraoperatively stable Lisfranc joint complex was interpreted as unstable on magnetic resonance imaging, and in another case an intraoperatively unstable Lisfranc joint complex was interpreted as stable on magnetic resonance imaging. The majority (eighteen) of the twenty-one feet demonstrated disruption of the second plantar tarsal-metatarsal ligament, which had little clinical correlation with instability. CONCLUSIONS: Magnetic resonance imaging is accurate for detecting traumatic injury of the Lisfranc ligament and for predicting Lisfranc joint complex instability when the plantar Lisfranc ligament bundle is used as a predictor. Rupture or grade-2 sprain of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals is highly suggestive of an unstable midfoot, for which surgical stabilization has been recommended. The appearance of a normal ligament is suggestive of a stable midfoot, and documentation of its integrity may obviate the need for a manual stress radiographic evaluation under anesthesia for a patient with equivocal clinical and radiographic examinations.

Magnetic resonance imaging findings in bipartite medial cuneiform - a potential pitfall in diagnosis of midfoot injuries: a case series.

INTRODUCTION: The bipartite medial cuneiform is an uncommon developmental osseous variant in the midfoot. To our knowledge, Magnetic Resonance Imaging (MRI) characteristics of a non-symptomatic bipartite medial cuneiform have not been described in the orthopaedic literature. It is important for orthopaedic foot and ankle surgeons, musculoskeletal radiologists, and for podiatrists to identify this osseous variant as it may be mistakenly diagnosed as a fracture or not recognized as a source of non-traumatic or traumatic foot pain, which may sometimes even require surgical treatment. CASE PRESENTATIONS: In this report, we describe the characteristics of three cases of bipartite medial cuneiform on Magnetic Resonance Imaging and contrast its appearance to that of a medial cuneiform fracture. CONCLUSION: A bipartite medial cuneiform is a rare developmental anomaly of the midfoot and may be the source of midfoot pain. Knowledge about its characteristic appearance on magnetic resonance imaging is important because it is a potential pitfall in diagnosis of midfoot injuries.

Retroperitoneal hematoma caused by a ruptured pelvic varix in a patient with iliac vein compression syndrome.

May-Thurner syndrome, or iliac vein compression syndrome (IVCS), is a rare but well-described entity. It refers to the formation of venous thrombus caused by compression of the left iliac vein, most commonly between the right iliac artery and lumbar vertebrae. Several variants of IVCS have been described, including unusual presenting symptoms, etiologies, and complications. The authors describe an unusual case of IVCS in which the patient presented with a left-sided retroperitoneal hematoma arising from a ruptured collateral venous varix shortly after the development of symptomatic left lower-extremity deep vein thrombosis.