Quantitative Skeletal Imaging and Image-Based Modeling in Pediatric Orthopaedics.

PURPOSE OF REVIEW: Musculoskeletal imaging serves a critical role in clinical care and orthopaedic research. Image-based modeling is also gaining traction as a useful tool in understanding skeletal morphology and mechanics. However, there are fewer studies on advanced imaging and modeling in pediatric populations. The purpose of this review is to provide an overview of recent literature on skeletal imaging modalities and modeling techniques with a special emphasis on current and future uses in pediatric research and clinical care. RECENT FINDINGS: While many principles of imaging and 3D modeling are relevant across the lifespan, there are special considerations for pediatric musculoskeletal imaging and fewer studies of 3D skeletal modeling in pediatric populations. Improved understanding of bone morphology and growth during childhood in healthy and pathologic patients may provide new insight into the pathophysiology of pediatric-onset skeletal diseases and the biomechanics of bone development. Clinical translation of 3D modeling tools developed in orthopaedic research is limited by the requirement for manual image segmentation and the resources needed for segmentation, modeling, and analysis. This paper highlights the current and future uses of common musculoskeletal imaging modalities and 3D modeling techniques in pediatric orthopaedic clinical care and research.

MmCMS: mouse models' consensus molecular subtypes of colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) primary tumours are molecularly classified into four consensus molecular subtypes (CMS1-4). Genetically engineered mouse models aim to faithfully mimic the complexity of human cancers and, when appropriately aligned, represent ideal pre-clinical systems to test new drug treatments. Despite its importance, dual-species classification has been limited by the lack of a reliable approach. Here we utilise, develop and test a set of options for human-to-mouse CMS classifications of CRC tissue. METHODS: Using transcriptional data from established collections of CRC tumours, including human (TCGA cohort; n = 577) and mouse (n = 57 across n = 8 genotypes) tumours with combinations of random forest and nearest template prediction algorithms, alongside gene ontology collections, we comprehensively assess the performance of a suite of new dual-species classifiers. RESULTS: We developed three approaches: MmCMS-A; a gene-level classifier, MmCMS-B; an ontology-level approach and MmCMS-C; a combined pathway system encompassing multiple biological and histological signalling cascades. Although all options could identify tumours associated with stromal-rich CMS4-like biology, MmCMS-A was unable to accurately classify the biology underpinning epithelial-like subtypes (CMS2/3) in mouse tumours. CONCLUSIONS: When applying human-based transcriptional classifiers to mouse tumour data, a pathway-level classifier, rather than an individual gene-level system, is optimal. Our R package enables researchers to select suitable mouse models of human CRC subtype for their experimental testing.

Genicular nerve radiofrequency ablation for the treatment of chronic knee joint pain: a real-world cohort study with evaluation of prognostic factors.

BACKGROUND: Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain. However, there has been minimal investigation of real-world, long-term outcomes and factors that predict treatment success after GNRFA. OBJECTIVES: To evaluate the effectiveness of GNRFA for chronic knee pain in a real-world population and identify predictive factors. METHODS: Consecutive patients who underwent GNRFA at a tertiary academic center were identified. Demographic, clinical, and procedural characteristics were collected from the medical record. Outcome data were numeric rating scale (NRS) pain reduction and Patient Global Impression of Change (PGIC). Data were collected by standardized telephone survey. Predictors of success were evaluated with logistic and Poisson regression analyses. RESULTS: Of the 226 total patients identified, 134 (65.6 ± 12.7; 59.7% female) were successfully contacted and analyzed, with a mean follow-up time of 23.3 ± 11.0 months. Of those, 47.8% (n = 64; 95% CI: 39.5%-56.2%) and 61.2% (n = 82; 95% CI: 52.7%-69.0%) reported ≥50% NRS score reduction and ≥2-point NRS score reduction, respectively, and 59.0% (n = 79; 95% CI: 50.5%-66.9%) reported "much improved" on the PGIC questionnaire. Factors associated with a greater likelihood of treatment success (P < .05) were higher Kellgren-Lawrence osteoarthritis grade (2-4 vs 0-1); no baseline opioid, antidepressant, or anxiolytic medication use; and >3 nerves targeted. CONCLUSION: In this real-world cohort, approximately half of the participants experienced clinically meaningful improvements in knee pain after GNRFA at an average follow-up time of nearly 2 years. Factors associated with higher likelihood of treatment success were more advanced osteoarthritis (Kellgren-Lawrence Grade 2-4); no opioid, antidepressant, or anxiolytic medication use; and >3 nerves targeted.

Beyond schwannomas and neurofibromas: a radiological and histopathological review of lesser-known benign lesions that arise in association with peripheral nerves.

Peripheral nerve sheath tumors comprise a significant percentage of both benign and malignant soft tissue tumors. The vast majority of these lesions are schwannomas and neurofibromas, which most radiologists are familiar with including the well-described multimodality imaging features. However, numerous additional often under-recognized benign entities associated with nerves exist. These rarer entities are becoming increasingly encountered with the proliferation of cross-sectional imaging, particularly magnetic resonance imaging (MRI). It is important for the radiologist to have a basic understanding of these entities as many have near-pathognomonic MR imaging features as well as specific clinical presentations that when interpreted in concert, often allows for a limited differential or single best diagnosis. The ability to provide a prospective, pre-intervention diagnosis based solely on imaging and clinical presentation is crucial as several of these entities are "do not touch" lesions, for which even a biopsy may have deleterious consequences. To our knowledge, the majority of these benign entities associated with nerves have only been described in scattered case reports or small case series. Therefore, the aim of this article is to provide a radiopathologic comprehensive review of these benign entities that arise in association with nerves with a focus on characteristic MRI features, unique histopathologic findings, and entity specific clinical exam findings/presentation.

Concepts in Musculoskeletal Bone and Soft Tissue Biopsy.

Imaging-guided needle biopsy of musculoskeletal lesions is a high-yield and low-risk procedure that can be used for definitive characterization of indeterminate bone and soft tissue lesions. Familiarity with the preprocedural, technical, and postprocedural steps is vital for the appropriate management of these cases. Biopsy request triage requires an awareness of definitively benign conditions and other tumor mimics. A complete clinical, laboratory, and imaging work-up is essential for procedural planning and determining pathologic concordance. Consultation with an orthopaedic oncologist is a requisite step to ensure maximizing biopsy yield and to avoid interference with any future limb-sparing surgical intervention. Knowledge of the equipment, pertinent medications, and appropriate biopsy technique can minimize the risk of periprocedural complications. Finally, the radiologist may be required to discuss the concordance of histopathology with preprocedure imaging, perform repeat image-guided biopsy, and carefully interpret sarcoma surveillance imaging examinations.

Percutaneous image-guided sternal biopsy: a cross-institutional retrospective review of diagnostic yield and safety in 50 cases.

OBJECTIVE: Image-guided sternal biopsy may be technically daunting given the immediately subjacent critical structures. There is a paucity of literature describing technique, safety, and efficacy. This study aims to quantify the diagnostic yield and safety of image-guided sternal biopsies. Secondary aims include (1) describing the preferred approach/technique and (2) identifying imaging features and disease entities associated with higher and lower diagnostic yields. MATERIALS AND METHODS: A retrospective review of 50 image-guided sternal biopsies performed at two quaternary care centers from 2000 to 2019 was performed. Recorded lesion-related variables included as follows: location, density, extraosseous extension, and size. Recorded variables from electronic medical records included as follows: patient demographics, histologic or microbiological diagnosis, and complications. Recorded technique-related variables included as follows: needle obliquity, type, and gauge; biopsy core number and length; and modality. RESULTS: Of the 50 biopsies, 88.0% resulted in a definitive histologic diagnosis. Six biopsies were non-diagnostic. The majority of biopsies were performed under computed tomography (88.0%), followed by ultrasound (12.0%). Tumor was the most common biopsy indication (90.0%), followed by infection (10.0%). Of the diagnostic biopsies indicated for tumor, 88.9% were malignant. Seventy-four percent of the lesions were predominantly lytic. Fifty percent of lesions had extraosseous extension. Lesion locations were as follows: manubrium (48.0%), sternal body (48.0%), and sternomanubrial joint (4.0%). No minor or major, acute, or delayed procedure-related complications were encountered. CONCLUSION: Image-guided sternal biopsy is an efficacious and safe method of obtaining a definitive histologic diagnosis regardless of lesion-specific features or location.

[Unstable injuries of the deltoid ligament complex in ankle fractures : How to diagnose, how to treat?] / Instabile Verletzungen des Deltabandkomplexes bei Sprunggelenkfrakturen : Wie erkennen, wie behandeln?

Unstable injuries of the deltoid ligament complex can have a substantial negative effect on the prognosis and treatment of ankle injuries. Lesions of the deltoid ligament are often overlooked at the initial presentation, both as isolated ruptures and in combination with more complex injuries of the ankle. Neglected unstable injuries of medial ankle ligaments may result in chronic instability, especially following correct treatment of fractures and lateral ligament injuries. These are accompanied by reduced ankle mobility, persisting pain, reduced load bearing and osteoarthritis. Despite the possible subsequent damage, the need for surgical repair of the deltoid ligament in patients with ankle fractures is controversially discussed. Although in most cases of ligament injuries of the upper ankle joint conservative treatment leads to very good results, there is increased interest in acute surgical treatment particularly for unstable injuries in order to avoid secondary instability and the associated sequelae. When surgical treatment should be given priority over conservative treatment has not yet been sufficiently clarified. This article gives an overview of the diagnosis and treatment of injuries of the deltoid ligament complex in patients with ankle fractures based on the current literature.

Perspectives Among Canadian Physicians on Factors Influencing Implementation of Mifepristone Medical Abortion: A National Qualitative Study.

PURPOSE: Access to family planning health services in Canada has been historically inadequate and inequitable. A potential solution appeared when Health Canada approved mifepristone, the gold standard for medical abortion, in July 2015. We sought to investigate the factors that influence successful initiation and ongoing provision of medical abortion services among Canadian health professionals and how these factors relate to abortion policies, systems, and service access throughout Canada. METHODS: We conducted 1-on-1 semistructured interviews with a national sample of abortion-providing and nonproviding physicians and health system stakeholders in Canadian health care settings. Our data collection, thematic analysis, and interpretation were guided by Diffusion of Innovation theory. RESULTS: We conducted interviews with 90 participants including rural practitioners and those with no previous abortion experience. In the course of our study, Health Canada removed mifepristone restrictions. Our results suggest that Health Canada's initial restrictions discouraged physicians from providing mifepristone and were inconsistent with provincial licensing standards, thereby limiting patient access. Once deregulated, remaining factors were primarily related to local and regional implementation processes. Participants held strong perceptions that mifepristone was the new standard of care for medical abortion in Canada and within the scope of primary care practice. CONCLUSION: Health Canada's removal of mifepristone restrictions facilitated the implementation of abortion care in the primary care setting. Our results are unique because Canada is the first country to facilitate provision of medical abortion in primary care via evidence-based deregulation of mifepristone.

Septic Arthritis: An Evidence-Based Review of Diagnosis and Image-Guided Aspiration.

OBJECTIVE. The purpose of this evidence-based review is to equip radiologists to discuss and interpret findings obtained with various imaging modalities, guide patient selection for percutaneous aspiration, and safely perform arthrocentesis to assess for infection in both native and prosthetic joints. CONCLUSION. Septic arthritis is an emergency that can lead to rapidly progressive, irreversible joint damage. Despite the urgency associated with this diagnosis, there remains a lack of consensus regarding many aspects of the management of native and periprosthetic joint infections.

Avulsion Injuries of the Hand and Wrist.

Injuries of the hand and wrist are frequently encountered in radiology. Avulsions of the hand and wrist are a heterogeneous group of injuries, but they often have a characteristic imaging appearance that relates to the intricate bone and soft-tissue anatomy and the mechanism of injury. The imaging appearance and this intricate form and function dictate treatment of hand and wrist avulsions. This article reviews frequently and infrequently encountered avulsion injuries and describes abnormalities that may mimic the imaging appearance of avulsions. Specifically discussed entities include the Bennett and reverse Bennett fracture, ulnar collateral ligament avulsion, radial and ulnar styloid process avulsion, triquetral avulsion, mallet and jersey finger, central slip avulsion, and acute and chronic volar plate avulsion injuries. Uncommon avulsion injuries are also described and include avulsions of the scapholunate ligament, extensor carpi radialis longus and brevis tendons, trapeziometacarpal ligament, radial collateral ligament, and flexor digitorum profundus tendon. Emphasis is placed on the relevant anatomy and typical imaging findings for each diagnosis, with pertinent clinical history, pathophysiologic evaluation, and treatment discussed briefly. Understanding the anatomy and expected imaging findings can aid the radiologist in recognizing and characterizing these injuries.©RSNA, 2020.

Pearls and Pitfalls for Soft-Tissue and Bone Biopsies: A Cross-Institutional Review.

Management of soft-tissue and bone neoplasms depends on a definitive histologic diagnosis. Percutaneous image-guided biopsy of bone and soft-tissue tumors is a cost-effective and accurate method to obtain a histopathologic diagnosis. Biopsy requests must be approached thoughtfully to avoid numerous potential pitfalls. Hasty biopsy planning places the patient at increased risk for misdiagnosis, delayed therapy, repeated invasive procedures, and substantial morbidity. Biopsy planning begins with a thorough review of the relevant clinical history and pertinent imaging. The biopsy route must be planned in concert with the referring orthopedic oncologist to preserve limb-sparing options. Carefully selecting the most appropriate imaging modality to guide the biopsy increases the chances of reaching a definitive diagnosis. It is also critical to identify and target with expertise the part of the lesion that is most likely to yield an accurate diagnosis. Percutaneous biopsy is a safe procedure, and familiarity with preprocedural laboratory testing parameters, anticoagulation guidelines, and commonly used sedation medications minimizes the risk of complications while ensuring patient comfort. Nondiagnostic biopsy results are not infrequent and may still have value in guiding patient treatment. Awareness of the imaging manifestations of tumor recurrence is also important. The aim of this article is to provide a comprehensive review of pertinent preprocedural, periprocedural, and postprocedural considerations for bone and soft-tissue musculoskeletal biopsies.The online slide presentation from the RSNA Annual Meeting is available for this article.©RSNA, 2020.

Asymmetric lambda sign of the second tarsometatarsal joint on axial weight-bearing cone-beam CT scans of the foot: preliminary investigation for diagnosis of subtle ligamentous Lisfranc injuries in a cadaveric model.

BACKGROUND: Subtle Lisfranc joint injuries remain challenging to diagnose. Although of questionable accuracy, the current gold standard to assess these injuries is through bilateral weight-bearing radiography. However, weight-bearing cone beam-computed tomography (CBCT), providing clearer visualization of bony landmarks, can also be utilized for evaluation. This study aims to establish the hypothesis that a specific weight-bearing CBCT finding (asymmetric lambda sign) can serve as an independent indicator of a subtle Lisfranc injury. METHODS: Weight-bearing CBCT images of 24 match-paired cadaveric legs were acquired, initially intact, and then following sequential dissection of each aspect (dorsal, interosseous, and plantar ligaments, respectively) of the Lisfranc ligamentous complex (LLC). All scans were taken in non- (NWB, 0 kg), partial- (PWB, 40 kg), and full-weight-bearing (FWB, 80 kg) manners. The lambda sign was then inspected axially for asymmetry (positive sign) by identifying three symmetrical joint spaces created between the medial cuneiform and the second metatarsal base (C1-M2), the medial and middle cuneiform (C1-C2), and the second metatarsal base and middle cuneiform (M2-C2). RESULTS: A positive sign was observed in 25.6% (221/864) of all studies. Most notably, the fully dissected specimens demonstrated an asymmetric lambda sign in 33.3%, 72.2%, and 83.3% in NWB, PWB, and FWB conditions, respectively. The inter- and intra-observer reliability kappa value was calculated to be 0.843 and 0.912. CONCLUSION: An asymmetric lambda sign is a simple and useful indicator for a complete LLC injury in PWB and FWB conditions using a cadaver model.

Imaging in Lisfranc injury: a systematic literature review.

OBJECTIVES: To systematically review current diagnostic imaging options for assessment of the Lisfranc joint. MATERIALS AND METHODS: PubMed and ScienceDirect were systematically searched. Thirty articles were subdivided by imaging modality: conventional radiography (17 articles), ultrasonography (six articles), computed tomography (CT) (four articles), and magnetic resonance imaging (MRI) (11 articles). Some articles discussed multiple modalities. The following data were extracted: imaging modality, measurement methods, participant number, sensitivity, specificity, and measurement technique accuracy. Methodological quality was assessed by the QUADAS-2 tool. RESULTS: Conventional radiography commonly assesses Lisfranc injuries by evaluating the distance between either the first and second metatarsal base (M1-M2) or the medial cuneiform and second metatarsal base (C1-M2) and the congruence between each metatarsal base and its connecting tarsal bone. For ultrasonography, C1-M2 distance and dorsal Lisfranc ligament (DLL) length and thickness are evaluated. CT clarifies tarsometatarsal (TMT) joint alignment and occult fractures obscured on radiographs. Most MRI studies assessed Lisfranc ligament integrity. Overall, included studies show low bias for all domains except patient selection and are applicable to daily practice. CONCLUSIONS: While conventional radiography can demonstrate frank diastasis at the TMT joints; applying weightbearing can improve the viewer's capacity to detect subtle Lisfranc injury by radiography. Although ultrasonography can evaluate the DLL, its accuracy for diagnosing Lisfranc instability remains unproven. CT is more beneficial than radiography for detecting non-displaced fractures and minimal osseous subluxation. MRI is clearly the best for detecting ligament abnormalities; however, its utility for detecting subtle Lisfranc instability needs further investigation. Overall, the available studies' methodological quality was satisfactory.

Naviculocuneiform and Second and Third Tarsometatarsal Articulations: Underappreciated Normal Anatomy and How It May Affect Fluoroscopy-Guided Injections.

OBJECTIVE: Because the second and third tarsometatarsal (TMT) and naviculocuneiform joints normally communicate, the least arthritic or technically most straightforward joint was injected when a fluoroscopically guided therapeutic injection was ordered for one or both joints. We hypothesized that pain relief would be equivalent regardless of the joint injected and would result in less radiation and a lower steroid dose compared with patients who had both articulations injected. MATERIALS AND METHODS: Seventy-eight patients were divided into four joint groups: naviculocuneiform requested and injected (n = 15), nonrequested naviculocuneiform or second and third TMT injected (n = 25), both injected (n = 23), and TMT requested and injected (n = 15). Variables recorded included patient age and sex, fluoroscopy time, steroid dose, pre- and postprocedural pain, osteoarthrosis (OA) grade, and confidence of intraarticular injection. Statistical analysis compared mean pain level change before and after injection, mean fluoroscopy time, and mean steroid dose between groups. The mean OA grade of the nonrequested joint was compared with that of the requested joint in patients whose injected and requested joints did not match (group 2). RESULTS: Pre- and postinjection pain reduction (p = 0.630) and postinjection pain (p = 0.935) were not significantly different. Mean steroid dose (p < 0.001) and fluoroscopy time (p = 0.0001) were significantly increased for the both joint injection group. Within the nonrequested naviculocuneiform or second and third TMT injection group, there was a significant difference in OA grade between injected (least arthritic) and requested joints (p = 0.001). CONCLUSION: When faced with challenging naviculocuneiform or second and third TMT joint injections, choosing the technically most straightforward joint may result in less radiation and steroid dose without compromising quality of care or pain reduction.

Pearls and pitfalls of fluoroscopic-guided foot and ankle injections: what the radiologist needs to know.

OBJECTIVE: This article provides a comprehensive, joint-by-joint review of fluoroscopic-guided foot and ankle injections and emphasizes pre-procedural planning, relevant anatomy, appropriate technique, troubleshooting the difficult procedure, and the importance of communicating unexpected findings with the referring clinician. The interrogation of pain generators including variant ossicles, fractures, and post-surgical/traumatic findings is also described. CONCLUSIONS: Even the most challenging foot and ankle injections may be successfully completed with a solid anatomical understanding and thoughtful approach.

Currently used imaging options cannot accurately predict subtalar joint instability.

PURPOSE: To give a systematic overview of current diagnostic imaging options and surgical treatment for chronic subtalar joint instability. METHODS: A systematic literature search across the following sources was performed: PubMed, ScienceDirect, and SpringerLink. Twenty-three imaging studies and 19 outcome studies were included. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2) tool was used to assess the methodologic quality of the imaging articles, while the modified Coleman Score was used to assess the methodologic quality of the outcome studies. RESULTS: Conventional radiographs were most frequently used to assess chronic subtalar joint instability. Talar tilt, anterior talar translation, and subtalar tilt were the three most commonly used measurement methods. Surgery often included calcaneofibular ligament reconstruction. CONCLUSION: Current imaging options do not reliably predict subtalar joint instability. Distinction between chronic lateral ankle instability and subtalar joint instability remains challenging. Recognition of subtalar joint instability as an identifiable and treatable cause of ankle pain requires vigilant clinical investigation. LEVEL OF EVIDENCE: Systematic Review of Level III and Level IV Studies, Level IV.

Lymphangiomatosis: a rare entity presenting with involvement of the sacral plexus.

Lymphangiomatosis is an uncommon disease process characterized by multisystem lymphatic malformations that can involve numerous body systems, including organs, muscles, soft tissues, and bones. Involvement of the nervous system is rare and has even been previously described as a site of sparing. We present a case of a 24-year-old female with known lymphangiomatosis, presenting with acute onset of lower extremity paresthesias, weakness, and new urinary retention. MRI of the pelvis revealed lymphangiomatosis of the sacral plexus, which has not been previously reported. We will review the clinical and imaging manifestations of lymphangiomatosis and provide a differential diagnosis for masses of the lumbosacral plexus. Although lower extremity pain and weakness encountered in the emergency department or outpatient setting is most frequently caused by lumbar spine pathology, occasionally, abnormalities of the lumbosacral plexus may prove to be the cause. While peripheral nerve sheath tumors lead the differential diagnosis of tumor or tumor-like entities involving the lumbosacral plexus, lymphangiomatosis is a rare differential consideration.

Imaging in syndesmotic injury: a systematic literature review.

OBJECTIVES: To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis. MATERIALS AND METHODS: A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality. RESULTS: The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice. CONCLUSIONS: Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

Postoperative Imaging in the Setting of Hip Preservation Surgery.

Osteoarthritis of the hip remains a prevalent disease condition that influences ever-changing treatment options. Procedures performed to correct anatomic variations, and, in turn, prevent or slow the progression of osteoarthritis, are aptly referred to as types of hip preservation surgery (HPS). Conditions that predispose individuals to femoroacetabular impingement (FAI), including pincer- and cam-type morphology, and hip dysplasia are specifically targeted in HPS. Common surgical interventions include acetabuloplasty, osteochondroplasty, periacetabular osteotomy (PAO), and derotational femoral osteotomy (DFO). The radiologist's understanding of the surgical approach, pre- and postoperative imaging findings, and common complications of HPS are paramount to providing value to the patient and surgeon. Acetabuloplasty and osteochondroplasty are performed to address pincer- and cam-type morphology in patients with FAI. With both of these HPS techniques, the goal is to restore the normal morphology by resecting excess bone in the acetabulum or femoral head or neck. As a result, a frequently encountered complication is incomplete or excessive resection. Excessive resection can predispose the patient to dislocation in the case of acetabuloplasty and fracture in the case of osteochondroplasty. Iatrogenic injury to adjacent structures such as the ischiofemoral ligament and acetabular cartilage also may occur. Although rare, especially when an arthroscopic approach is used, avascular necrosis remains a risk. Femoral head undercoverage in hip dysplasia is corrected by using PAO, which may be performed as the sole procedure or in conjunction with DFO. Incomplete or excessive rotation during surgery can result in postprocedural complications. As with any orthopedic procedure involving osteotomy, nonhealing is a risk. Iatrogenic injury in the form of fracture or hardware failure also may be seen. ©RSNA, 2016.

Cubonavicular Coalition: Magnetic Resonance Imaging Findings and Associated Pathology of a Rarely Reported Condition in 27 Patients.

RATIONALE AND OBJECTIVES: (1) Describe multimodality imaging of cubonavicular coalition (CNC) with magnetic resonance imaging (MRI) focus, (2) evaluate CNC associated foot and ankle pathology, (3) examine clinical presentation/symptoms associated with CNC, (4) record CNC treatment. MATERIALS AND METHODS: Retrospective Institutional Review Board (IRB) approved study. Picture Archiving and Communication System (PACS) databases searched for CNC. Final study population: 34 cases in 27 patients. Each CNC was reviewed for: coalition type (osseous versus non-osseous- cartilaginous versus fibrous), tendon and ligament pathology, bone marrow edema at CNC and adjacent joints, presence and severity of degenerative changes at CNC and adjacent joints, fractures, additional coalitions, laterality, and pes planus. MRI planes and radiographic views on which coalitions were best identified were recorded. Each CNC EMR was reviewed for: symptoms, trauma, management, patient demographics. Inter-reader reliability was performed for type of non-osseous coalition. RESULTS: Final cohort included 34 cases in 27 patients (average age: 34.7, range: 10-76; 71% female). No CNC was completely osseous. On MRI, 89.5% of coalitions were non-osseous and 5.3% were partially osseous. 76.5% of patients had referable symptoms including pain, limited motion, inability to bear weight. 23.5% of patients were surgically managed/pathologically proven. On MRI, 36.8% of patients had tendon pathology, 52.6% had ligamentous pathology, 100% had bone marrow edema-like signal abnormality about the CNC, and 88.2% had CNC degenerative changes. There was bone marrow edema-like signal abnormality at bones adjacent to the CNC in 52.6% and adjacent joint degenerative disease present in 50%. CNC was best identified on oblique radiographs and axial MRI. Inter-reader reliability for non-osseous coalition type was poor, Cronbach's alpha 0.554. CONCLUSION: CNC is subtle and findings of osteoarthritis or bone marrow edema-like about the cubonavicular articulation should raise suspicion for underlying coalition.