Local and Systemic Side Effects of Corticosteroid Injections for Musculoskeletal Indications.

Corticosteroid injections can be associated with a range of potential side effects, which may be classified as local or systemic and further stratified as immediate or delayed in onset. Radiologists performing image-guided musculoskeletal injections should recognize the potential side effects of corticosteroid medication when counseling patients before injection and consider such side effects in planning individual injections. This Review summarizes the available evidence regarding the local and systemic side effects of corticosteroid injections performed for musculoskeletal indications. Local side effects include postinjection flare, skin hypopigmentation and atrophy, infection, tendon rupture, accelerated progression of osteoarthritis, and osseous injury. Systemic side effects include adrenal suppression or insufficiency, facial flushing, hypertension, hyperglycemia, and osteoporosis. Additional targeted counseling is warranted regarding side effects that are specific to certain patient populations (i.e., premenopausal women, patients with diabetes, athletes, and pediatric patients). Corticosteroid injections are contraindicated in the presence of superficial or deep infection, fracture, or a prosthetic joint. Guidelines on the frequency, duration, and maximal lifetime use of corticosteroid injections are currently lacking. Further research is needed regarding the long-term complications of continuous corticosteroid use, particularly with regard to osseous effects.

MRI of patellar stabilizers: Anatomic visibility, inter-reader reliability, and intra-reader reproducibility of primary and secondary ligament anatomy.

OBJECTIVE: To compare MRI features of medial and lateral patellar stabilizers in patients with and without patellar instability. METHODS: Retrospective study of 196 patients (mean age, 33.1 ± 18.5 years; 119 women) after diagnosis of patellar instability (cohort-1, acute patellar dislocation; cohort-2, chronic patellar maltracking) or no patellar instability (cohort-3, acute ACL rupture; cohort-4, chronic medial meniscus tear). On MRI, four medial and four lateral stabilizers were evaluated for visibility and injury by three readers independently. Inter- and intra-reader agreement was determined. RESULTS: Medial and lateral patellofemoral ligaments (MPFL and LPFL) were mostly or fully visualized in all cases (100%). Of the secondary patellar stabilizers, the medial patellotibial ligament was mostly or fully visualized in 166 cases (84.7%). Other secondary stabilizers were mostly or fully visualized in only a minority of cases (range, 0.5-32.1%). Injury scores for all four medial stabilizers were higher in patients with acute patellar dislocation than the other 3 cohorts (p < .05). Visibility inter- and intra-reader agreement was good for medial stabilizers (κ 0.61-0.78) and moderate-to-good for lateral stabilizers (κ 0.40-0.72). Injury inter- and intra-reader agreement was moderate-to-excellent for medial stabilizers (κ 0.43-0.90) and poor-to-moderate for lateral stabilizers (κ 0-0.50). CONCLUSION: The MPFL and LPFL were well visualized on MRI while the secondary stabilizers were less frequently visualized. The secondary stabilizers were more frequently visualized medially than laterally, and patellotibial ligaments were more frequently visualized compared to the other secondary stabilizers. Injury to the medial stabilizers was more common with acute patellar dislocation than with chronic patellar maltracking or other knee injuries.

Knee MRI: Meniscus Roots, Ramps, Repairs, and Repercussions.

Menisci play an essential role in maintaining normal pain-free function of the knee. While there are decades of MRI literature on the tears involving the meniscus body and horns, there is now a surge in knowledge regarding injuries at the meniscus roots and periphery. The authors briefly highlight new insights into meniscus anatomy and then summarize recent developments in the understanding of meniscus injuries that matter, emphasizing meniscus injuries at the root and peripheral (eg, ramp) regions that may be missed easily at MRI and arthroscopy. Root and ramp tears are important to diagnose because they may be amenable to repair. However, if these tears are left untreated, ongoing pain and accelerated cartilage degeneration may ensue. The posterior roots of the medial and lateral menisci are most commonly affected by injury, and each of these injuries is associated with distinctive clinical profiles, MRI findings, and tear patterns. Specific diagnostic pitfalls can make the roots challenging to evaluate, including MRI artifacts and anatomic variations. As with root tears, MRI interpretation and orthopedic treatment have important differences for injuries at the medial versus lateral meniscus (LM) periphery (located at or near the meniscocapsular junction). Medially, ramp lesions typically occur in the setting of an anterior cruciate ligament rupture and are generally classified into five patterns. Laterally, the meniscocapsular junction may be injured in association with tibial plateau fractures, but disruption of the popliteomeniscal fascicles may also result in a hypermobile LM. Updated knowledge of the meniscus root and ramp tears is crucial in optimizing diagnostic imaging before repair and understanding the clinical repercussions. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available in the Online Learning Center.

Patellar Tracking: An Old Problem with New Insights.

Patellofemoral pain and instability are common indications for imaging that are encountered in everyday practice. The authors comprehensively review key aspects of patellofemoral instability pertinent to radiologists that can be seen before the onset of osteoarthritis, highlighting the anatomy, clinical evaluation, diagnostic imaging, and treatment. Regarding the anatomy, the medial patellofemoral ligament (MPFL) is the primary static soft-tissue restraint to lateral patellar displacement and is commonly reconstructed surgically in patients with MPFL dysfunction and patellar instability. Osteoarticular abnormalities that predispose individuals to patellar instability include patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Clinically, patients with patellar instability may be divided into two broad groups with imaging findings that sometimes overlap: patients with a history of overt patellar instability after a traumatic event (eg, dislocation, subluxation) and patients without such a history. In terms of imaging, radiography is generally the initial examination of choice, and MRI is the most common cross-sectional examination performed preoperatively. For all imaging techniques, there has been a proliferation of published radiologic measurement methods. The authors summarize the most common validated measurements for patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Given that static imaging is inherently limited in the evaluation of patellar motion, dynamic imaging with US, CT, or MRI may be requested by some surgeons. The primary treatment strategy for patellofemoral pain is conservative. Surgical treatment options include MPFL reconstruction with or without osseous corrections such as trochleoplasty and tibial tubercle osteotomy. Postoperative complications evaluated at imaging include patellar fracture, graft failure, graft malposition, and medial patellar subluxation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Patterns of ankle injury in soccer: MRI clues to traumatic mechanism.

Understanding the traumatic mechanisms of ankle injuries in soccer is crucial for an accurate and complete MRI diagnosis. Many ankle injuries share universal mechanisms seen in other athletic activities, but certain patterns are found to be more specific and relatively unique to soccer. Ankle impingement syndromes encountered in soccer encompass a spectrum of disorders that include anterior and posterior impingement categories, with anterior impingement representing pathology relatively specific to soccer. Lateral ligamentous sprains are one of the most common injuries; however, there is a higher rate of injuries to the medial structures in soccer as compared to other sports. Ankle fractures are uncommon in soccer while bone contusions and chondral and osteochondral injuries frequently accompany ligamentous sprains. Tendon abnormalities in soccer most commonly result from overuse injuries and typically affect peroneal tendons, posterior and anterior tibialis tendons, and Achilles tendon. Acute Achilles tendon ruptures occur in both recreational players and elite soccer athletes. Tibialis anterior friction syndrome may mimic tibial stress fractures. Long-term sequelae of acute traumatic and chronic overuse ankle injuries in professional soccer players manifest as ankle osteoarthritis that is more prevalent compared to not only the general population, but also to former elite athletes from other sports. This article examines the most common and specific injuries in soccer in order of their frequency.

Slow-growing buttock mass after failure of incorporation of autologous fat transfer for gluteal augmentation: ultrasound and MRI features.

Gluteal augmentation procedures are gaining popularity and encompass a variety of surgical techniques and methods of graft preparation. While surgical history remains essential for diagnosis, the radiologist must avoid pitfalls and rely on imaging features to recognize both the expected appearance and complications of gluteal augmentation procedures. We report a case of a slowly growing buttock mass after gluteal augmentation with autologous fat transfer 1 year after surgery. The potential diagnostic imaging pitfalls and characteristics on ultrasound and contrast-enhanced MRI are discussed. Multiplicity of fat-containing lesions depicted on large field-of-view images and granulated appearance of the intralesional fat on MRI should allow the radiologist to recognize the appearance of failed fat graft incorporation that can present as a slowly growing encapsulated collection with layered fat and fluid contents.

Magnetic resonance imaging of the ankle and foot.

This article reviews the magnetic resonance imaging (MRI) findings of the normal anatomy and various pathologic conditions of the ankle and foot commonly encountered in clinical practice. The spectrum of entities discussed includes osseous and osteochondral injuries, ligamentous injuries, common traumatic and degenerative tendon pathology, abnormalities of transverse tarsal joint (Chopart) and tarsometatarsal joint (Lisfranc) complexes, pathological conditions affecting capsuloligamentous structures of the great toe and lesser toes, as well as pedal infection, with a focus on diabetic osteomyelitis and neuropathic osteoarthropathy.

Magnetic resonance imaging of the elbow.

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

Nomenclature of Subchondral Nonneoplastic Bone Lesions.

OBJECTIVE. The purpose of this article is to summarize the nomenclature of nonneoplastic conditions affecting subchondral bone through a review of the medical literature and expert opinion of the Society of Skeletal Radiology Subchondral Bone Nomenclature Committee. CONCLUSION. This consensus statement summarizes current understanding of the pathophysiologic characteristics and imaging findings of subchondral nonneoplastic bone lesions and proposes nomenclature to improve effective communication across clinical specialties and help avoid diagnostic errors that could affect patient care.

Added value of MRI to X-ray in guiding the extent of surgical resection in diabetic forefoot osteomyelitis: a review of pathologically proven, surgically treated cases.

OBJECTIVE: This study retrospectively evaluated the added value of MRI over X-ray in guiding the extent of amputation in a cohort of patients with surgically treated, pathologically proven osteomyelitis. MATERIALS AND METHODS: A database search revealed 32 cases of pathology-proven diabetic forefoot osteomyelitis between 2006 and 2016, in which X-ray, MRI, and surgery occurred within 30 days. Data collection included extent of osteomyelitis reported on imaging and extent of subsequent amputation using a point system. Added value of MRI over X-ray in guiding surgical resection was stated if the X-ray was negative, MRI was positive, and there was MRI-surgical concordance; if both modalities were positive, X-ray was discordant whereas the MRI was concordant; or if MRI detected an abscess. Two-tailed Fisher's exact test compared proportions. RESULTS: In 9 cases that were positive on both modalities, MRI identified an average of 1.2 additional bone segments of disease. There was surgical agreement with X-ray in 3 out of 31 cases (9.7%, 95%CI 0-20.1) and with MRI in 17 out of 31 cases (55%, 37.3-72.4; p < 0.0001). There was an added value of MRI over X-ray in guiding surgical treatment in 64.5% of cases (95% CI 47.7%-81.4%). MRI added value in 5 out of 9 X-rays positive for osteomyelitis and in 15 out of 22 negative (p value was not significant). CONCLUSION: Magnetic resonance imaging demonstrated added value over X-ray in guiding surgical management in both X-ray-negative and -positive cases. Although multiple factors are involved in determining the degree of surgical excision, MRI is a clinically useful component of the diagnostic algorithm in patients who undergo surgical treatment.

Osteochondral Lesions of the Knee: Differentiating the Most Common Entities at MRI.

Several pathologic conditions may manifest as an osteochondral lesion of the knee that consists of a localized abnormality involving subchondral marrow, subchondral bone, and articular cartilage. Although understanding of these conditions has evolved substantially with the use of high-spatial-resolution MRI and histologic correlation, it is impeded by inconsistent terminology and ambiguous abbreviations. Common entities include acute traumatic osteochondral injuries, subchondral insufficiency fracture, so-called spontaneous osteonecrosis of the knee, avascular necrosis, osteochondritis dissecans, and localized osteochondral abnormalities in osteoarthritis. Patient demographics, the clinical presentation, and the role of trauma are critical for differential diagnosis. A localized osteochondral defect can be created acutely or can develop as an end result of several chronic conditions. MRI features that aid in diagnosis include the location and extent of bone marrow edema, the presence of a fracture line, a hypointense area immediately subjacent to the subchondral bone plate, and deformity of the subchondral bone plate. These findings are essential in diagnosis of acute traumatic injuries, subchondral insufficiency fracture, and its potentially irreversible form, spontaneous osteonecrosis of the knee. If the lesion consists of a subchondral region demarcated from the surrounding bone, the demarcation should be examined for completeness and the presence of a "double-line sign" that is seen in avascular necrosis or findings of instability, which are important for proper evaluation of osteochondritis dissecans. Subchondral bone plate collapse, demonstrated by the presence of a depression or a fluid-filled cleft, can be seen in advanced stages of both avascular necrosis and subchondral insufficiency fracture, indicating irreversibility. Once the diagnosis is established, it is important to report pertinent MRI findings that may guide treatment of each condition. ©RSNA, 2018 An earlier incorrect version of this article appeared online. This article was corrected on August 23, 2018.

Plantar talar head contusions and osteochondral fractures: associated findings on ankle MRI and proposed mechanism of injury.

OBJECTIVE: To evaluate the significance of plantar talar head injury (PTHI) in predicting osseous and soft tissue injuries on ankle MRI. MATERIALS AND METHODS: The IRB approved this HIPAA-compliant retrospective study. The study group consisted of 41 ankle MRIs with PTHI that occurred at our institution over a 5 ½ year period. Eighty MRIs with bone injuries in other locations matched for age, time interval since injury, and gender formed a control group. Injuries to the following structures were recorded: medial malleolus, lateral malleolus/distal fibula, posterior malleolus, talus, calcaneus, navicular, cuboid, lateral, medial and syndesmotic ligaments, spring ligament complex, and extensor digitorum brevis (EDB) muscle. Twenty separate logistic regressions determined which injuries PTHI predicted, using the Holm procedure to control for family-wise alpha at 0.05. RESULTS: PTHI strongly predicted the occurrence of injuries involving the anterior process of the calcaneus [24 % of cases, odds ratio (OR) 12.66], plantar components of the spring ligament (27 %, OR 9.43), calcaneal origin of the EDB and attachment of the dorsolateral calcaneocuboid ligament (22 %, OR 7.22), cuboid (51 %, OR 6.58), EDB (27 %, OR 5.49), anteromedial talus (66 %, OR 4.78), and posteromedial talus (49 %, OR 4.48). PTHI strongly predicted lack of occurrence of syndesmotic ligament injury (OR 19.6). The PTHI group had a high incidence of lateral ligamentous injury (78 %), but not significantly different from the control group (53 %). CONCLUSIONS: PTHI is strongly associated with injury involving the transverse tarsal joint complex. We hypothesize it results from talo-cuboid and/or talo-calcaneal impaction from a supination injury of the foot and ankle.

Unstable osteochondral fragment of the lateral femoral condyle containing the popliteus tendon origin. Report of three cases.

We report a series of three cases of unusual locations of chronic osteochondral fragments arising from the posterolateral aspect of the lateral femoral condyle, presenting acutely in young adults, in which the unstable fragment contained the origin of the popliteus tendon, with MRI and arthroscopic correlation. Although atypical, we hypothesize that these cases represent adult osteochondritis dissecans with extension to a popliteus tendon origin. Preoperative diagnosis of popliteus tendon involvement may influence clinical management in patients with an unstable osteochondral fragment in this location.

Inverted verrucous carcinoma of the buttock mimicking abscess and gossypiboma: MR and pathologic correlation.

Verrucous carcinoma (VC) is an uncommon, low-grade variant of squamous cell carcinoma. Its benign histologic appearance and indolent course may lead to a delayed diagnosis. We report a rare case of an inverted verrucous carcinoma of the buttock presenting as a slow-growing subcutaneous lesion with a draining sinus and no exophytic component, clinically mimicking abscess and gossypiboma, with magnetic resonance imaging (MRI) and pathologic correlation. Biopsy of the lesional base is mandatory for accurate diagnosis. An enhancement pattern with a convoluted undulating appearance in a subcutaneous lesion displayed on MRI should raise a consideration of inverted VC in the differential diagnosis.

Complete Bilateral Ankle Fusion: A Rare Complication of Ankylosing Spondylitis.

Ankylosing spondylitis (AS) is a chronic inflammatory disorder primarily affecting the axial skeleton and is strongly associated with a positive human leukocyte antigen B27 (HLA-B27) genotype. Patients typically present with chronic low back pain that typically starts before the age of 40 years. Common initial clinical features include lower back, hip, and joint pain with stiffness that is worse in the morning and with inactivity. As the disease progresses over a prolonged period, it leads to fusion of sacroiliac joints and ankylosis of the vertebrae with the iconic "bamboo spine" on imaging. Joint fusion or ankylosis is the sequela of either undiagnosed or untreated AS. We report a case of a 69-year-old male with complete fusion of the ankle joint, hindfoot, and midfoot of both feet in the clinical context of an incidental finding of an ankylosed spine on computed tomography (CT) imaging. The ankle joint is a very uncommon site for fusion in ankylosing spondylitis. We would like to suggest the terminology "boot sign" for this rare radiographic finding of complete ankle and subtalar fusion given the appearance of a boot. "Boot sign" is associated with either inability to ambulate or a steppage gait from loss of ankle dorsiflexion as a result of ankle and hindfoot fusion with or without fusion of forefoot and midfoot.

Imaging and Treatment of Posttraumatic Ankle and Hindfoot Osteoarthritis.

Posttraumatic osteoarthritis of the ankle and hindfoot is a common and frequently debilitating disorder. 70% to 90% of ankle osteoarthritis is related to prior trauma that encompasses a spectrum of disorders including fractures and ligamentous injuries that either disrupt the articular surface or result in instability of the joint. In addition to clinical evaluation, imaging plays a substantial role in the treatment planning of posttraumatic ankle and hindfoot osteoarthritis. Imaging evaluation must be tailored to specific clinical scenarios and includes weight bearing radiography that utilizes standard and specialty views, computed tomography which can be performed with a standard or a weight bearing technique, magnetic resonance imaging, and ultrasound evaluation. This review article aims to familiarize the reader with treatment rationale, to provide a brief review of surgical techniques and to illustrate expected imaging appearances of common operative procedures performed in the setting of posttraumatic ankle and hindfoot osteoarthritis, such as joint-preserving procedures, ankle fusion, subtalar fusion, tibiotalarcalcaneal fusion and ankle arthroplasty. Preoperative findings will be discussed along with the expected postoperative appearance of various procedures in order to improve detection of their complications on imaging and to provide optimal patient care.

Imaging and Laboratory Workup for Hand Infections.

Hand infections can lead to significant morbidity if not treated promptly. Most of these infections, such as abscesses, tenosynovitis, cellulitis, and necrotizing fasciitis, can be diagnosed clinically. Laboratory values, such as white blood cell count, erythrocyte sedimentation rate, C-reactive protein, and recently, procalcitonin and interleukin-6, are helpful in supporting the diagnosis and trending disease progression. Radiographs should be obtained in all cases of infection. Ultrasound is a dynamic study that can provide quick evaluation of deeper structures but is operator dependent. Computed tomographic and MRI studies are useful for evaluating deep space or bony infections and preoperative surgical planning.

ACR Appropriateness Criteria® Acute Trauma to the Ankle.

Acute injuries to the ankle are frequently encountered in the setting of the emergency room, sport, and general practice. This ACR Appropriateness Criteria defines best practices for imaging evaluation for several variants of patients presenting with acute ankle trauma. The variants include scenarios when Ottawa Rules can be evaluated, when there are exclusionary criteria, when Ottawa Rules cannot be evaluated, as well as specific injuries. Clinical scenarios are followed by the imaging choices and their appropriateness with an accompanying narrative explanation to help physicians to order the most appropriate imaging test. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.