Imaging of Total Ankle Arthroplasty: Normal Imaging Findings and Hardware Complications.

End-stage ankle osteoarthritis often significantly impacts patients' quality of life. This can be managed surgically either by ankle arthrodesis or total ankle arthroplasty (TAA). Although ankle arthrodesis is considered by some as the standard-of-care surgical option for this condition, it restricts range of motion and may lead to accelerated osteoarthritis of neighboring joints. Better understanding of ankle biomechanics, the biological effects of orthopaedic devices, and new surgical techniques have led to significant improvements in the designs of TAAs, and over the last several decades TAA has been used increasingly to treat patients with end-stage tibiotalar osteoarthritis. However, complication and ultimate failure rates remain greater than those seen with total knee and hip arthroplasty, and imaging is often critical in determining whether a prosthesis is beginning to fail. As a result, imagers should be familiar with the basic types of TAAs in clinical use, the normal radiographic appearances, as well as the common complications seen with this procedure.

Correction to: Sonographic evaluation of uncommonly assessed upper extremity peripheral nerves: anatomy, technique, and clinical syndromes.

The original version of this article unfortunately contained mistake. Fig. 13a (Anatomy of the Ulnar Digital nerve of the Thumb) as originally published erroneously depicts the ulnar digital nerve of the thumb as a branch of the ulnar nerve.

Initial experience with dual-energy computed tomography-guided bone biopsies of bone lesions that are occult on monoenergetic CT.

OBJECTIVE: Our purpose was to determine whether dual-energy CT (DECT), specifically the bone marrow setting of the virtual noncalcium (VNCa) algorithm, could be used to identify and accurately biopsy suspected bone malignancies that were visible on magnetic resonance imaging (MRI), nuclear bone scintigraphy, or positron-emission tomography/computed tomography (PET/CT), but occult on monoenergetic computed tomography (CT) by virtue of being either isodense or nearly isodense to surrounding normal bone. MATERIALS AND METHODS: We present 4 cases in which DECT was used to detect various malignant bone lesions and was successfully used to direct percutaneous DECT-guided bone biopsies. RESULTS: Two of the lesions were solid tumor metastases (breast and prostate carcinoma), whereas two others were hematological malignancies (leukemia and lymphoma). This technique enabled us to confidently and accurately direct the biopsy needle into the target lesion. CONCLUSION: The authors demonstrate that the DECT VNCa bone marrow algorithm may be helpful in identifying isodense bone lesions of various histologies and may be used to guide percutaneous bone biopsies. This technique may help to maximize diagnostic yield, minimize the number of passes into the region of concern, and prevent patients from undergoing repeat biopsy.

Sonographic evaluation of uncommonly assessed upper extremity peripheral nerves: anatomy, technique, and clinical syndromes.

Targeted ultrasound of the median, ulnar, and radial nerves is a well-established technique for suspected upper extremity peripheral neuropathy. However, sonographic imaging of the brachial plexus and smaller peripheral nerve branches is more technically difficult and the anatomy is less familiar to many radiologists. As imaging techniques improve, many clinicians refer patients for imaging of previously less-familiar structures. In addition, some patients may present with injuries that could involve local neurovascular structures. Finally, patients presenting with isolated peripheral neuropathies may be referred for perineural injections with local anesthetic for diagnostic purposes, or steroid for therapeutic reasons. This requires sonologists to have a firm understanding of the courses of these nerves and the surrounding anatomic landmarks that can be used to accurately identify and characterize them. We discuss clinical syndromes referable to specific peripheral nerve branches in the upper extremity, the relevant anatomy, and sonographic technique.

Gonadal steroid-dependent effects on bone turnover and bone mineral density in men.

BACKGROUND: Severe gonadal steroid deficiency induces bone loss in adult men; however, the specific roles of androgen and estrogen deficiency in hypogonadal bone loss are unclear. Additionally, the threshold levels of testosterone and estradiol that initiate bone loss are uncertain. METHODS: One hundred ninety-eight healthy men, ages 20-50, received goserelin acetate, which suppresses endogenous gonadal steroid production, and were randomized to treatment with 0, 1.25, 2.5, 5, or 10 grams of testosterone gel daily for 16 weeks. An additional cohort of 202 men was randomized to receive these treatments plus anastrozole, which suppresses conversion of androgens to estrogens. Thirty-seven men served as controls and received placebos for goserelin and testosterone. Changes in bone turnover markers, bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA), and BMD by quantitative computed tomography (QCT) were assessed in all men. Bone microarchitecture was assessed in 100 men. RESULTS: As testosterone dosage decreased, the percent change in C-telopeptide increased. These increases were considerably greater when aromatization of testosterone to estradiol was also suppressed, suggesting effects of both testosterone and estradiol deficiency. Decreases in DXA BMD were observed when aromatization was suppressed but were modest in most groups. QCT spine BMD fell substantially in all testosterone-dose groups in which aromatization was also suppressed, and this decline was independent of testosterone dose. Estradiol deficiency disrupted cortical microarchitecture at peripheral sites. Estradiol levels above 10 pg/ml and testosterone levels above 200 ng/dl were generally sufficient to prevent increases in bone resorption and decreases in BMD in men. CONCLUSIONS: Estrogens primarily regulate bone homeostasis in adult men, and testosterone and estradiol levels must decline substantially to impact the skeleton. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00114114. FUNDING: AbbVie Inc., AstraZeneca Pharmaceuticals LP, NIH.