A primer on skeletal dysplasias.

Skeletal dysplasia encompasses a heterogeneous group of over 400 genetic disorders. They are individually rare, but collectively rather common with an approximate incidence of 1/5000. Thus, radiologists occasionally encounter skeletal dysplasias in their daily practices, and the topic is commonly brought up in radiology board examinations across the world. However, many radiologists and trainees struggle with this issue because of the lack of proper resources. The radiological diagnosis of skeletal dysplasias primarily rests on pattern recognition-a method that is often called the "Aunt Minnie" approach. Most skeletal dysplasias have an identifiable pattern of skeletal changes composed of unique findings and even pathognomonic findings. Thus, skeletal dysplasias are the best example to which the Aunt Minnie approach is readily applicable.

Non-infectious thoracic discitis: A diagnostic and management dilemma. A report of two cases with review of the literature.

Discitis/ Osteomyelitis is an inflammatory process involving an intervertebral disc and the adjacent vertebral bodies. Infection is the most common cause of discitis, which is often spontaneous and hematogenous in origin. However, many noninfectious processes affecting the spine such as pseudarthrosis in ankylosing spondylitis, amyloidosis, destructive spondyloarthropathy of hemodialysis, Modic changes type 1, neuropathic arthropathy, calcium pyrophosphate dehydrate (CPPD) spondyloarthropathy and gout can mimic infectious discitis/ osteomyelitis. To determine whether a particular patient's spinal process is due to an infectious versus non-infectious cause can be challenging. Although clinical findings and laboratory studies including erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) can be helpful in the diagnosis of bacterial discitis/osteomyelitis due to their high sensitivity; however, their specificity is low. Moreover, both the infectious and non-infectious discitis can appear quite similar on the imaging studies. We present two cases of thoracic discitis with adjacent vertebral osteomyelitis of probable non-infectious etiology. Both were managed with instrumented fusion for stabilization. We also discuss a range of noninfectious causes of discitis/spondylitis and their radiological features which can help differentiate from infectious processes.

Sex Difference in Contusion of the Medial Femoral Condyle Rim-Association with MRI Occult Meniscal Tears in the ACL Deficient Knee.

Background: Meniscal tears, specifically lateral meniscal tears, have a larger than expected un-derdiagnosis rate in the presence of an ACL tear. The purpose of our study was to search for an MRI bone contusion pattern associated with MRI occult meniscal tears in patients with an ACL tear, specifically a contusion of the rim of the medial femoral condyle (RMFC). Our hypothesis was that there would be a significant association between RMFC contusions and MRI occult meniscal tears in patients with an ACL tear. We also searched for a difference between sexes with respect to the presence of the RMFC contusion in the setting of an occult meniscal tear. We also categorized the type, size, and location of these occult meniscal tears in the setting of an ACL tear. Methods: This was a retrospective study that examined characteristics of occult meniscal tears and their association with a RMFC bone contusion. IRB approval was obtained. The date range of the study was June 2009 through December 2015. 6392 consecutive knee MRI reports in patients with an ACL deficient knee were reviewed. The study group included 22 patients with MRI occult meniscal tears, the control group included 110 patients. Relevant statistical values were calculated. Results: The most common type of occult meniscal tears were small radial and small longitudinal tears of the lateral meniscus. Occult meniscal tears were associated with an RMFC contusion in the study group (p=0.0457), particularly in males (p = 0.0003). In males with a torn ACL, the sensitivity of an RMFC contusion for an occult meniscal tear was 80%. Conclusion: In males with an ACL tear, there was a significant association between a contusion of the RMFC and an occult meniscal tear (commonly small radial or small peripheral partial-thickness longitudinal tears). RMFC contusions were reliably identified by radiologists in this study.Level of Evidence: II.

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.

Diagnostic accuracy of 3D color volume-rendered CT images for peroneal tendon dislocation in patients with acute calcaneal fractures.

BACKGROUND: Use of three-dimensional (3D) color volume-rendered (VR) images has been reported to be more time-efficient compared to that of cross-sectional computed tomography (CT) images for the diagnosis of peroneal tendon dislocation. However, the diagnostic performance of this technique has not been studied. PURPOSE: To test diagnostic accuracy of 3D color VR CT images of ankle for peroneal tendon dislocation in patients with acute calcaneal fractures. MATERIAL AND METHODS: The study consisted of 121 ankle CT studies from 105 consecutive patients (85 men, 20 women; mean age, 42 years; age range, 16-75 years) with acute calcaneal fractures. Peroneal tendon dislocation was diagnosed on multiplanar CT images by consensus of two experienced musculoskeletal radiologists, which served as the reference standard. Three other musculoskeletal radiologists independently reviewed 3D images alone on a workstation. The readers determined whether or not there was peroneal tendon dislocation using three degrees of certainty (definite, probable, and possible). Diagnostic performance of 3D images for peroneal tendon dislocation was evaluated by calculating the sensitivities, specificities, and area under the receiver-operating characteristic (ROC) curves. RESULTS: Forty-eight (40%) out of 121 studies showed peroneal tendon dislocation based on the expert readings using multiplanar reformatted images. Sensitivities/specificities of 3D images measured 0.92/0.81, 0.88/0.90, and 0.81/0.92 for three readers, respectively. The area under the proper binormal ROC curve based on all three readers (0.93, 0.94, and 0.92) measured 0.93 with a 95% confidence interval of 0.89-0.98. CONCLUSION: Diagnostic accuracy of 3D images is comparable to, but not as good as that of MPR images for the diagnosis of peroneal tendon dislocation in patients with acute calcaneal fractures.

Radiographic sizing for meniscal transplantation using 3-D CT reconstruction.

In meniscus transplantation, allograft size mismatch causes increased contact pressures and early degeneration of the knee. The purpose of this study is to compare the accuracy and reliability of sizing the tibial plateau using three-dimensional (3-D) computed tomography (CT) scans versus plain radiographs (XR). Anteroposterior (AP) and lateral XR as well as CT with 3-D reconstructions were performed on 16 cadaveric knees. Sagittal and coronal dimensions of the hemiplateaus were measured on each imaging modality and then on the disarticulated specimens. CT estimates of plateau size were closer to anatomic measurements compared with radiographic estimates in all dimensions and these differences were statistically significant (p < 0.0001). CT scan fell within 5 mm of anatomic measurements 100% of the time versus 76.5% for XR and within 2 mm 71.9% of the time versus 34.4%. The proportion of CT measurements within 2 mm of actual values was significantly higher for CT for the lateral meniscus on AP (p = 0.0011) and lateral (p = 0.0039) views. 3-D CT has less error in measurement of the tibial plateau than XR and estimates were more likely to be within 2 and 5 mm of actual size. This may decrease the likelihood of allograft size mismatch.

ACR appropriateness criteria(®) acute trauma to the knee.

There are more than 1 million visits to the ER annually in the United States for acute knee trauma. Many of these are twisting injuries in young patients who can walk and bear weight, and emergent radiography is not required. Several clinical decision rules have been devised that can considerably reduce the number of radiographic studies ordered without missing a clinically significant fracture. Although fractures are seen on only 5% of emergency department knee radiographs, 86% of knee fractures result from blunt trauma. In patients with falls or twisting injuries who have focal tenderness, effusion, or inability to bear weight, radiography should be the first imaging study performed. If radiography shows no fracture, MRI is best for evaluating for a suspected meniscal or ligament tear or patellar dislocation. Patients with knee dislocation should undergo radiography and MRI, as well as fluoroscopic angiography, CT angiography, or MR angiography. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Osteonecrosis of the distal tibia metaphysis after a Salter-Harris I injury: a case report.

Posttraumatic osteonecrosis has been well described as a common phenomenon seen in fractures of the femoral neck, talus, and scaphoid. In the following case, we describe posttraumatic osteonecrosis in a rare location: the distal tibia. Our report details a child who sustained a distal tibia physeal injury and subsequently developed radiographic findings consistent with aseptic necrosis. Besides a traumatic incident, the patient did not have any of the risk factors known to cause osteonecrosis. Awareness of this complication after Salter-Harris I fractures will help reduce time to diagnosis and optimize treatment.

ACR Appropriateness Criteria® on acute shoulder pain.

The shoulder joint is a complex array of muscles, tendons, and capsuloligamentous structures that has the greatest freedom of motion of any joint in the body. Acute (<2 weeks) shoulder pain can be attributable to structures related to the glenohumeral articulation and joint capsule, rotator cuff, acromioclavicular joint, and scapula. The foundation for investigation of acute shoulder pain is radiography. Magnetic resonance imaging is the procedure of choice for the evaluation of occult fractures and the shoulder soft tissues. Ultrasound, with appropriate local expertise, is an excellent evaluation of the rotator cuff, long head of the biceps tendon, and interventional procedures. Fluoroscopy is an excellent modality to guide interventional procedures. Computed tomography is an excellent modality for characterizing complex shoulder fractures. Computed tomographic arthrography or fluoroscopic arthrography may be alternatives in patients for whom MR arthrography is contraindicated. A multimodal approach may be required to accurately assess shoulder pathology. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

The role of the radiologist when encountering osteoporosis in women.

OBJECTIVE: This article describes the extent and potentially devastating consequences of osteoporosis in adult women. There is discussion of the importance of radiologists in the correct diagnosis and reporting of probable osteoporotic vertebral fractures on medical imaging studies. CONCLUSION: The Genant semiquantitative method for diagnosing osteoporotic vertebral fractures is presented. The importance of dual-energy x-ray absorptiometry reproducibility is also briefly discussed.

ACR appropriateness criteria on metastatic bone disease.

Appropriate imaging modalities for screening, staging, and surveillance of patients with suspected and documented metastatic disease to bone include (99m)Tc bone scanning, MRI, CT, radiography, and 2-[(18)F]fluoro-2-deoxyglucose-PET. Clinical scenarios reviewed include asymptomatic stage 1 breast carcinoma, symptomatic stage 2 breast carcinoma, abnormal bone scan results with breast carcinoma, pathologic fracture with known metastatic breast carcinoma, asymptomatic well-differentiated and poorly differentiated prostate carcinoma, vertebral fracture with history of malignancy, non-small-cell lung carcinoma staging, symptomatic multiple myeloma, osteosarcoma staging and surveillance, and suspected bone metastasis in a pregnant patient. No single imaging modality is consistently best for the assessment of metastatic bone disease across all tumor types and clinical situations. In some cases, no imaging is indicated. The recommendations contained herein are the result of evidence-based consensus by the ACR Appropriateness Criteria((R)) Expert Panel on Musculoskeletal Radiology.

Patient-physician communication: informed consent for imaging-guided spinal injections.

PURPOSE: Historically, informed-consent forms have been developed for the purpose of educating patients. However, informed-consent forms can be very difficult to understand. The hypothesis of this study was that a method using diagrams would improve patient-physician communication without increasing the time required to obtain informed consent over the teach-the-teacher method, as well as over current standard informed-consent protocol. METHODS: Ninety-nine of 109 patients undergoing spinal injections agreed to participate and completed this prospective, randomized, controlled study. The patients were randomly assigned to the control group (informed consent obtained in the customary manner at the investigators' institution, with 12 key points of consent and home care discussed conversationally), the teach-the-teacher group (patients had to repeat the 12 key points to the physicians before informed consent was complete), and the diagram group (patients viewed a set of diagrams illustrating the 12 key points before signing the informed-consent form). After the procedure, the patients completed a survey to test knowledge recall, anxiety, and pain during the procedure. RESULTS: Statistically significant results included a lower survey score for the control group, longer time required for the teach-the-teacher group than the control group, and a negative correlation between age and survey score in the teach-the-teacher group. CONCLUSIONS: The diagram method required less time than the teach-the-teacher method, had no negative correlation in survey score results with age, and had improved patient-physician communication over the control group.

Long-term results of reconstruction for treatment of a flexible cavovarus foot in Charcot-Marie-Tooth disease.

BACKGROUND: Cavovarus foot deformity is common in patients with Charcot-Marie-Tooth disease. Multiple surgical reconstructive procedures have been described, but few authors have reported long-term results. The purpose of this study was to evaluate the long-term results of an algorithmic approach to reconstruction for the treatment of a cavovarus foot in these patients. METHODS: We evaluated twenty-five consecutive patients with Charcot-Marie-Tooth disease and cavovarus foot deformity (forty-one feet) who had undergone, between 1970 and 1994, a reconstruction consisting of dorsiflexion osteotomy of the first metatarsal, transfer of the peroneus longus to the peroneus brevis, plantar fascia release, transfer of the extensor hallucis longus to the neck of the first metatarsal, and in selected cases transfer of the tibialis anterior tendon to the lateral cuneiform. Each patient completed standardized outcome questionnaires (the Short Form-36 [SF-36] and Foot Function Index [FFI]). Radiographs were evaluated to assess alignment and degenerative arthritis, and gait analysis was performed. The mean age at the time of follow-up was 41.5 years, and the mean duration of follow-up was 26.1 years. RESULTS: Correction of the cavus deformity was well maintained, although most patients had some recurrence of hindfoot varus as seen on radiographic examination. The patients had a lower mean SF-36 physical component score than age-matched norms, and the women had a lower mean SF-36 physical component score than the men, although this difference was not significant. Smokers had lower mean SF-36 scores and significantly higher mean FFI pain, disability, and activity limitation subscores (p < 0.0001). Seven patients (eight feet) underwent a total of eleven subsequent foot or ankle operations, but no patient required a triple arthrodesis. Moderate-to-severe osteoarthritis was observed in eleven feet. With the numbers studied, the age at surgery, age at the time of follow-up, and body mass index were not noted to have a significant correlation with the SF-36 or FFI scores. CONCLUSIONS: Use of the described soft-tissue procedures and first metatarsal osteotomy to correct cavovarus foot deformity results in lower rates of degenerative changes and reoperations as compared with those reported at the time of long-term follow-up of patients treated with triple arthrodesis.

ACR Appropriateness Criteria on suspected osteomyelitis in patients with diabetes mellitus.

Imaging of the diabetic foot is among the most challenging areas of radiology. The authors present a consensus of the suggested tests in several clinical scenarios, such as early neuropathy, soft-tissue swelling, skin ulcer, and suspected osteomyelitis. In most of these situations, magnetic resonance imaging (MRI) with or without contrast is the examination of choice. Most other imaging tests have complementary roles. For soft-tissue swelling or an ulcer, radiography and MRI with or without contrast are suggested. Bone scintigraphy with white blood cell scanning is used when MRI is contraindicated. In patients with diabetes without ulcers, radiography and MRI with or without contrast are suggested; bone scanning may be used when MRI is contraindicated.

Lumbar spine MRI in the elite-level female gymnast with low back pain.

OBJECTIVE: Previous studies have shown increased degenerative disk changes and spine injuries in the competitive female gymnast. However, it has also been shown that many of these findings are found in asymptomatic athletic people of the same age. Previous magnetic resonance imaging (MRI) studies evaluating the gymnastic spine have not made a distinction between symptomatic and asymptomatic athletes. Our hypothesis is that MRI will demonstrate the same types of abnormalities in both the symptomatic and asymptomatic gymnasts. DESIGN: Olympic-level female gymnasts received prospectively an MRI exam of the lumbar spine. Each of the gymnasts underwent a physical exam by a sports medicine physician just prior to the MRI for documentation of low back pain. Each MRI exam was evaluated for anterior apophyseal ring avulsion injury, compression deformity of the vertebral body, spondylolysis, spondylolisthesis, degenerative disease, focal disk protrusion/extrusion, muscle strain, epidural mass, and bone-marrow edema. PATIENTS: Nineteen Olympic-level female gymnasts (age 12-20 years) were evaluated prospectively in this study. All of these gymnasts were evaluated while attending a specific training camp. RESULTS: Anterior ring apophyseal injuries (9/19) and degenerative disk disease (12/19) were common. Spondylolysis (3/19) and spondylolisthesis (3/19) were found. Focal bone-marrow edema was found in both L3 pedicles in one gymnast. History and physical exam revealed four gymnasts with current low back pain at the time of imaging. There were findings confined to those athletes with current low back pain: spondylolisthesis, spondylolysis, bilateral pedicle bone-marrow edema, and muscle strain. CONCLUSIONS: Our initial hypothesis was not confirmed, in that there were findings that were confined to the symptomatic group of elite-level female gymnasts.

Orthopedic hardware complications diagnosed with multi-detector row CT.

PURPOSE: To retrospectively evaluate multi-detector row computed tomography (CT) for the depiction of orthopedic hardware complications in the spine and appendicular skeleton. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; patient informed consent was not required. Results of 114 multi-detector row CT studies performed because of possible hardware complications in 109 patients (57 men, 52 women; mean age, 44 years; age range, 12-82 years) were available for analysis. The CT studies were retrospectively reviewed and compared with clinical or surgical outcomes, which were used as the reference standard. In another experiment, detection of hardware complications on radiographs and multi-detector row CT images was compared between two readers for selected cases (18 positive and 26 negative) by using receiver operating characteristic (ROC) methods. RESULTS: For 91 (80%) of 114 multi-detector row CT studies, the complication status could be determined on the basis of clinical or surgical outcomes. Twenty-three multi-detector row CT studies were confirmed to be positive (revealing 10 cases of nonunion, five cases of hardware malplacement, three cases of hardware loosening, three perihardware fractures, and two chronic infections), and 57 were confirmed to be negative. There were three false-positive and eight false-negative multi-detector row CT studies. With clinical or surgical outcomes as the reference standard, the sensitivity, specificity, and positive and negative predictive values of multi-detector row CT were 74% (23 of 31 studies), 95% (57 of 60 studies), 88% (23 of 26 studies), and 88% (57 of 65 studies), respectively. Results of ROC analysis indicated that detection of hardware complications was much lower with radiography than with multi-detector row CT (area under ROC curve, 0.84 vs 1.00; F = 4.69, df = 1, 43; P < .05). CONCLUSION: Multi-detector row CT is an effective tool for depicting orthopedic hardware complications.

Patellar fractures after total knee replacement.

OBJECTIVE: The objective of our study was to describe the patterns of patellar fracture after total knee replacement and assess their clinical significance. MATERIALS AND METHODS: A retrospective review of patellar fractures after total knee replacement was performed. Seventeen cases were identified over a 10-year period. Radiographs, radiology reports, medical records, and operative notes were reviewed and analyzed. The clinical analysis included the time to fracture, the patient's symptoms and signs, whether the extensor mechanism was disrupted, and the treatment administered for the fracture. The radiographic analysis included fracture pattern, displacement, patellar position, presence of patellar osteonecrosis, and presence of soft-tissue abnormality. RESULTS: The incidence of patellar fractures after total knee replacement was 1.14%. The mean time from total knee replacement to patellar fracture was 17.5 months. Nine fractures were asymptomatic and identified on routine follow-up radiographs. The patterns of fracture were diverse: Transverse (n = 6), comminuted (n = 2), vertical (n = 5), and avulsion (n =4) fractures were seen. Thirteen fractures were displaced. Patellar osteonecrosis was suspected in four fractures, and three fractures were associated with disruption of the quadriceps tendons. Thirteen fractures were treated nonoperatively, and four were treated surgically. CONCLUSION: Patellar fractures are an uncommon, but important, complication after total knee replacement. Radiologists should be familiar with the imaging features of these fractures and their clinical significance.