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Normal skeletal development in the pediatric ankle is dynamic and often produces variable imaging appearances that are subject to misinterpretation. Radiologists must understand the underlying developmental phenomena, such as endochondral and membranous ossification and physeal fusion, and be familiar with their common and uncommon imaging manifestations unique to the pediatric ankle. This is especially true as the use of MRI in the evaluation of musculoskeletal trauma expands among younger populations. The authors focus on MRI evaluation of the skeletally maturing pediatric ankle and present pearls for accurately distinguishing normal findings and imaging pitfalls from true pathologic findings. The normal but often variable imaging findings of preossification, secondary ossification, and multiple ossification centers, as well as the range of bone marrow signal intensities that can be visualized within ossification centers, are described, along with tips to help differentiate these from true pathologic findings such as contusion, fracture, or tumor. The authors also review dynamic periosteal and physeal contributions to bone growth to highlight helpful distinguishing features and avoid misdiagnosis of common subperiosteal and periphyseal abnormalities. For example, the normal trilaminar appearance of the immature cortex and periosteum should not be mistaken for periosteal reaction, traumatic stripping, or subperiosteal hematoma. In addition, the physis can have several confusing but normal appearances, including normal physeal undulations (eg, Kump bump) or focal periphyseal edema, which should not be mistaken for pathologic findings such as physeal fracture, infection, or bar. ©RSNA, 2020.

BackgroundCompressive osseointegration is a promising modality for limb salvage in distal femoral oncologic tumors. However, few studies have explored short-term survival rates in a large patient cohort of distal femur compressive endoprostheses or highlighted the risk factors for spindle failures.Questions/purposesWe asked: (1) What is the frequency of compressive osseointegration spindle failure in distal femoral reconstructions? (2) What are the characteristics of rotational failure cases with distal femur compressive osseointegration endoprostheses? (3) What are the risk factors for mechanical and rotational failure of distal femur compressive osseointegration implantation? (4) What are other modalities of failure or causes of revision surgery, which affect patients undergoing distal femur compressive osseointegration implantation for oncologic reconstruction?MethodsBetween 1996 and 2013, 127 distal femoral reconstructions with the Compress(®) prosthesis were performed in 121 patients. During that time, 116 Compress(®) prostheses were implanted for aggressive primary tumors of the distal femur and/or failure of previous oncologic reconstruction. This approach represented approximately 91% of the distal femoral reconstructions performed during that time. Of the patients with prostheses implanted, four patients (four of 116, 3%) had died, and 37 (37 of 116, 32%) were lost to followup before 24 months. The median followup was 84 months (range, 24-198 months), and 71 patients (66% of all patients) were seen within the last 3 years. A retrospective chart review was performed to determine failure modality as defined by radiographs, clinical history, and intraoperative findings. Risk factors including age, sex, BMI, resection length, and perioperative chemotherapy were analyzed to determine effect on spindle and rotational failure rates. Survival analysis was determined using the Kaplan-Meier estimator. Differences in survival between groups were analyzed using the log rank test. Risk factors were determined using Cox proportional hazard modeling.ResultsSpindle survival at 5 and 10 years was 91% (95% CI, 82%-95%). Survival rates from rotational failure at 5 and 10 years were 92% (95% CI, 83%-96%); the majority of failures occurred within the first 2 years postoperatively and were the result of a twisting mechanism of injury. With the numbers available, none of the potential risk factors examined were associated with mechanical failure. The 5-year and 10-year all-cause revision-free survival rates were 57% (95% CI, 44%-67%) and 50% (95% CI, 36%-61%), respectively.ConclusionsDistal femur compressive osseointegration is a viable method for endoprosthetic reconstruction. Rotational failure is rare with the majority occurring early. No variables were found to correlate with increased risk of mechanical failure. More research is needed to evaluate methods of preventing mechanical and rotational failures in addition to other common causes of revision such as infection in these massive endoprosthetic reconstructions.Level of evidenceLevel IV, therapeutic study.

BACKGROUND: Previous studies have suggested suboptimal use of cardiac medications for secondary prevention after myocardial infarction (MI) and atrial fibrillation (AF), especially among older people. OBJECTIVE: To determine whether patients older than 75 years are less likely than those aged 65 to 74 to be prescribed medications with evidence-based indications, including angiotensin-converting enzyme (ACE) inhibitors for left ventricular dysfunction (LVD) and/or diabetes mellitus (DM), aspirin and/or β-blockers for those with a history of MI, and warfarin for chronic AF. DESIGN: A retrospective cohort study. SETTING: Twenty-nine hospitals, predominantly tertiary-care institutions. PARTICIPANTS: A total of 407 patients randomized to ventricular or dual-chamber pacing from February 26, 1993, to September 30, 1994, in the Pacemaker Selection in the Elderly (PASE) trial. MEASUREMENTS: A review of the patient's medical history and a physical exam at study enrollment, three follow-up timepoints, and a study closeout. RESULTS: Patients older than 75 years with LVD and/or DM were less likely to be prescribed ACE inhibitors (OR = .56 (0.31-1.00)); patients older than 75 with a history of MI were less likely to be taking aspirin (OR = .43 (0.19-.95)), and patients older than 75 with AF were less likely to be prescribed warfarin (OR = .18 (0.05-.61)). Patients older than 75 years of age with any or all of the conditions studied were less likely to be prescribed indicated medications than those ages 65 to 74 (OR = .35 (0.18-.70)), after controlling for between-group differences in comorbidity, gender, and number of noncardiac medications. CONCLUSION: Older age is a significant independent negative correlate of evidence-based cardiac medication use in this cohort. Causes for this finding need to be explored. J Am Geriatr Soc 47:145–150, 1999.