Purpose To assess the ability of volar locked plating to achieve and maintain normal radiographic parameters for articular stepoff, volar tilt, radial inclination, ulnar variance, and radial height in distal radius fractures. Methods We performed a retrospective review of 185 distal radius fractures that underwent volar locked plating with a single plate design over a 5-year period. We reviewed radiographs and recorded measurements for volar tilt, radial inclination, ulnar variance, radial height, and articular stepoff. We used logistic regression to determine the association between return to radiographic standard norms and fracture type. Results At the first and final postoperative follow-up visits, we observed articular congruence less than 2 mm in 92% of fractures at both times. Normal volar tilt (11°) was restored in 46% at the first follow-up and 48% at the final one. Radial inclination (22°) was achieved in 44% at the first follow-up and 43% at the final one, and ulnar variance (01 ± 2 mm) was achieved in 53% at the first follow-up and 53% at the final one. In addition, radial height (14 ± 1mm) was restored in 14% at the first follow-up and 12% at the final one. More complex, intra-articular fractures (AO class B and C and Frykman types 3, 4, 7, and 8) were less likely to be restored to normal radiographic parameters. However, because of the small sample size for some fracture types, it was difficult to discover significant associations between fracture type and radiographic outcome. Conclusions Volar locked plating for distal radius fractures achieved articular stepoff less than 2 mm in most fractures but only restored and maintained normal radiographic measurements for volar tilt, radial inclination, and ulnar variance in 50% of fractures. The ability of volar locked plating to restore and maintain ulnar variance and volar tilt decreased with more complex intra-articular fracture types.

Transarticular spread of tumor is rare; it has only been reported in the sacroiliac joint, intervertebral disk spaces, and facet joints. The anatomic and kinetic characteristics of the sacroiliac joint, as well as the changes the joint undergoes during a lifetime, make it particularly vulnerable to transarticular tumor invasion. Although extremely rare, Ewing sarcoma can extend through the sacroiliac joint and be virtually indistinguishable radiologically from septic arthritis. Furthermore, the clinical presentation of a child with Ewing sarcoma can be similar to that of a child with osteomyelitis. Laboratory values are quite nonspecific and are not always helpful in differentiating between the entities. Therefore, the possibility of sacroiliac joint transarticular Ewing sarcoma should be considered in a child presenting with hip pain, despite clinical, radiological and laboratory findings suggesting an infectious process.

The observation of a bubble of gas at the most non-dependent margin of a lytic bone lesion which has sustained a pathologic fracture implies that the lesion is hollow and can assist the radiologist in making the diagnosis of a unicameral bone cyst. The imaging studies of two patients who sustained pathologic fractures through unicameral bone cysts and exhibited the "rising bubble" sign are shown. The sign's basis, proper utilization, and potential pitfalls are discussed.

Tenosynovial chondromatosis is a benign chondrogenic metaplasia of extra-articular synovial tissue. The most common locations for tenosynovial chondromatosis to develop are the hands and feet. The condition has rarely been reported in children. We present a case of tenosynovial chondromatosis of the flexor hallucis longus in a 17-year-old girl. The presentation was unusual not only due to the location and young age of the patient but also the absence of any palpable mass on physical exam and complete lack of calcification of the cartilage bodies. Initial diagnosis was made by MRI. The patient underwent tenosynovectomy with an excellent postoperative recovery at 6-month follow-up. Histopathology confirmed the diagnosis of tenosynovial chondromatosis.

Shoulder lesions range from tumor-like lesions such as simple bone cysts to aggressive high-grade sarcomas. The clinical presentation is often nonspecific with shoulder pain as the primary complaint, which may lead to a delayed or missed diagnosis. Delayed diagnosis or a poorly planned biopsy of a malignant shoulder lesion can have a detrimental effect on the patient's prognosis and treatment options. Because the initial patient assessment is crucial for successful treatment, knowledge of the key features of common shoulder tumors and tumor-like conditions can help determine the diagnosis and treatment plan. This article reviews the key features and treatment options of the more commonly encountered benign and malignant shoulder bone and soft-tissue tumors and tumor-like conditions.

Presented are two cases of minute amounts of vacuum phenomena within the central portion of the lateral compartments of two knee joints, mimicking torn discoid lateral menisci. In each case, only the gradient echo images were able to correctly characterize the minute quantities of intraarticular gas by demonstrating ''blooming'' magnetic susceptibility artifact. The signal characteristics of the intraarticular gas were identical to those of fibrocartilage on all of the remaining routine, fast spin echo, ''sports protocol'' magnetic resonance imaging sequences.Key Words: vacuum phenomenon; intraarticular gas; discoid meniscus; pitfalls in magnetic resonance imaging of the knee; gradient recalled echo; spin echo J. Magn. Reson. Imaging 2010;31:698-702. V C 2010 Wiley-Liss, Inc.IN OUR PRACTICE, we have traditionally employed 3D gradient recalled echo (GRE) sequences to evaluate the articular cartilage, as well as to assess for postoperative changes (magnetic susceptibility artifact from microscopic metallic debris) and chondrocalcinosis. The exquisite anatomic detail provided by today's fatsaturated proton density-weighted (PDW) fast spin echo sequences has rendered the GRE sequences seemingly redundant in the assessment of the articular cartilage. In fact, on several occasions we have considered eliminating the GRE sequence from our sports knee magnetic resonance imaging (MRI) protocol altogether in order to save 5 minutes of scan time per examination. Occasionally, the ability to see microscopic metallic debris on GRE sequences within or around a meniscus or along a portal track in Hoffa's fat pad can be helpful in the evaluation of the menisci, especially when no clinical information is available and we question the possibility of a prior partial meniscectomy. The cases we present demonstrate another potential role of the GRE sequence in the sports protocol knee MRI exam: its ability to detect minute amounts of intraarticular vacuum or gas. Such tiny volumes of gas were not detectable by the fast spin echo sequences. What appeared to be frayed or torn discoid lateral menisci on the fast spin echo sequences were, in fact, minute amounts of intraarticular gas trapped within the central portion of the lateral compartments of our patients' knees. CASE REPORTS Case OneA 15-year-old male reported a 7-8-month history of right anterior knee pain which began following a roller-skating injury when he fell and struck his knee on the ground. In addition to pain, he described some swelling, limping, and occasional popping sensations while ambulating. He was otherwise healthy, with no significant past medical history.On physical examination, the patient was overweight and was found to have some mild swelling of his right knee, as well as a small joint effusion. He had normal strength, normal gait, and no laxity at the knee. He was tender to palpation over the joint lines, patellar tendon, and patello-femoral joint. A threeview plain radiographic series of the knee obtained on the date of his clinic visit (not pictured) demons...

Chordomas are rare, locally aggressive notochordal tumors, which most frequently occur in the neuraxis. We describe the case of a 74-year-old male with a history of renal cell carcinoma, who presented with a slowly enlarging mass in his left leg. While the clinical history and imaging suggested metastatic renal cell carcinoma, immunohistochemical staining with brachyury ultimately made the diagnosis of extra-axial chordoma. At 74 years of age, our patient is the oldest ever reported with bony extra-axial chordoma objectively confirmed by brachyury staining. A detailed case discussion and a review of the available literature on this rare clinicopathologic entity are provided.

Rationale and Objectives-The aim of this study was to explore the reliability of osteopenia diagnosis based on digital radiographs of appendicular skeleton obtained as part of routine clinical practice as compared with DEXA (Dual energy X-ray absorptiometry) gold standard (Z-score < -1).Materials and Methods-The study was an IRB-approved retrospective study of 58 children (mean age 12 years [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]). Digital radiographs of appendicular skeleton obtained within 6 months of DEXA scanning were presented in a blinded fashion to two musculoskeletal radiologists who were instructed to grade the level of mineralization. Sensitivity and specificity of each reviewer's osteopenia grading were calculated in comparison to lumbar DEXA Z-score values. Interobserver agreement was also calculated and significance evaluated with Bowker's test.Results-The reviewers correctly identified 28% of all patients with severe osteopenia (Z-score ≤ −2.0) as well as 26% of all patients with mild osteopenia (−2 < Z-score < −1). Inter observer agreement for the correct diagnosis of BMD category ranged from 71% for normal BMD (Zscore>-1) to 0 and 25% for mild and severe osteopenia respectively.Conclusions-Visual diagnosis of osteopenia based on digital radiographs of appendicular skeleton has poor sensitivity and interobserver agreement. Clinical features and risk factors of pediatric patients should therefore guide DEXA evaluation and treatment recommendations.