Chapter 46 discusses joint arthroplasties and prostheses. Replacement of a native joint is often the definitive treatment of joint pain that does not respond to conservative measures. Joint replacement is the next most common orthopedic procedure after fracture reduction and fixation. Joint replacement anatomically may be total, partial, or compartmental. Regarding movement, it may be constrained, semiconstrained, or unconstrained. Radiography is the initial step in imaging evaluation with other modalities, especially CT and MRI, used when radiographs are inconclusive. Radiographs can detect particle disease, however, the damage caused by granulomas or pseudotumors are best evaluated with MRI using metal artifact reduction software (MARS).

This article discusses instrumented spinal surgeries, the radiologic assessment of spinal fixation hardware, and the potential complications of spinal hardware. Radiography is the standard for the postoperative assessment of spinal hardware. Computed tomography and magnetic resonance imaging play a valuable role in the detection of hardware and postsurgical-related complications such as infection, pseudarthrosis, and malpositioned instrumentation. Familiarity with the normal imaging appearance of implanted spinal hardware along with the expected progression of normal postoperative osseous arthrodesis enables recognition of potential complications and helps facilitate appropriate clinical management.

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Physician medical licensure is state based for historical and constitutional reasons. It may also provide the best method for guaranteeing patient protection from unqualified, incompetent, impaired, or unprofessional practitioners of medicine. However, a significant cost for physicians practicing telemedicine is having to obtain multiple state medical licenses. There is reasonable likelihood that model legislation for the practice of telemedicine across state boundaries will be passed in the next few years, providing physicians with a simpler process for license reciprocity in multiple states via interstate licensing compacts. Physicians would have to be licensed in the state in which the patient resides. Patient complaints would still be adjudicated by the medical licensing board in the state where the patient resides according applicable state legislation.

This article reviews the University of Arizona's more than 15 years of experience with teleradiology and provides an overview of university-based teleradiology practice in the United States (U.S.). In the U.S., teleradiology is a major economic enterprise with many private for-profit companies offering national teleradiology services (i.e., professional interpretation of radiologic studies of all types by American Board of Radiology certified radiologists). The initial thrust for teleradiology was for after-hours coverage of radiologic studies, but teleradiology has expanded its venue to include routine full-time or partial coverage for small hospitals, clinics, specialty medical practices, and urgent care centers. It also provides subspecialty radiologic coverage not available at smaller medical centers and clinics. Many U.S. university-based academic departments of radiology provide teleradiology services usually as an additional for-profit business to supplement departmental income. Since academic-based teleradiology providers have to compete in a very demanding marketplace, their success is not guaranteed. They must provide timely, high-quality professional services for a competitive price. Academic practices have the advantage of house officers and fellows who can help with the coverage, and they have excellent subspecialty expertise. The marketplace is constantly shifting, and university-based teleradiology practices have to be nimble and adjust to ever-changing situations.

Commercial teleradiology is well established in the US. There are many factors to consider when engaging a teleradiology provider. One of the basic questions is what do you expect to gain from it? Do you want a final reading from an attending radiologist (known as a consultant radiologist in many countries) or would you be satisfied with a preliminary reading from a teleradiology provider and a final reading from your own in-house radiologist the following day? Do you simply require after-hours coverage or do you need to supplement the coverage provided by your own internal radiologists during normal working hours? Teleradiology is not without its drawbacks. It can add additional costs, particularly for after-hours coverage. Teleradiology rarely provides in-house coverage for procedures, and the interpreting radiologist may sometimes be difficult to contact for consultation. Choosing a teleradiology vendor requires due diligence. When the contracting entity defines its expectations well and chooses its teleradiology vendor with care, the end result will be satisfactory for all concerned, including the patients.

Background: Humeral avulsion of the inferior glenohumeral ligament is a rare injury resulting from hyperabduction and external rotation, and it is most commonly seen with sports-related injuries, including those from volleyball. The anterior band of the inferior glenohumeral ligament is most commonly injured (93%), whereas the posterior band is infrequently injured. The axillary pouch humeral avulsion of the inferior glenohumeral ligament as a result of repetitive microtrauma has not been yet described in the English literature. Hypothesis: Humeral avulsions of the inferior glenohumeral ligaments are identifiable in volleyball players without acute injuries, and they have a unique pathologic pattern in these athletes. Study Design: Case series; Level of evidence, 4. Methods: Four female college volleyball players with pain in their dominant shoulder and with inferior capsular laxity and/or instability—without a known history of trauma or dislocation of the same shoulder—were referred by an experienced sports medicine orthopaedic surgeon for the magnetic resonance arthrogram procedure of the same shoulder. The imaging findings were retrospectively correlated with the initial interpretation and arthroscopic findings. Results: All 4 patients had an axillary pouch humeral avulsion of the inferior glenohumeral ligament. Three had articular surface partial-thickness rotator cuff tear, and 3 had a labral tear. All were outside hitters or middle blockers who consequently performed multiple hitting maneuvers in practice and games. Conclusion: Repetitive microtrauma from overhead hitting in volleyball generates forces on the inferior capsule of the shoulder joint that may cause inferior capsular laxity and subsequent failure of the humeral side of the axillary pouch portion of the inferior glenohumeral ligament.

Teaching physicians are paid by Medicare Part B on a fee-for-service basis, but if a teaching physician does not participate in a given patient service or document this participation properly, the teaching physician cannot legally bill Medicare for these services. In fact, Medicare has severely fined academic practice plans that lacked such documentation [ 1 University of North Carolina HospitalsCoding and compliance. http://www.med.unc.edu/credentialing/OnlineCredentialingRadiology.ppt Google Scholar ]. Such documentation is also felt to be a requirement for other federal and state agencies as well as private insurance companies and other payers, and it is a common practice for academic medical centers across the country to require such documentation from their teaching physicians [ 2 Centers for Medicare and Medicaid ServicesPub 100-04 Medicare claims processing: transmittal 811. http://www.cms.gov/transmittals/downloads/R811CP.pdf Google Scholar , 3 University of North Texas Health Science Center, Office of Regulatory ComplianceClinical documentation & compliance manual: a guide to documentation, coding, and billing of medical services for compliance. http://www.hsc.unt.edu/policies/QuAssure/Clinical%20Documentation&ComplianceManual042704.pdf Google Scholar ].

Retained foreign objects (RFOs) after surgery present considerable risk to both patients and health care organizations. In addition to postprocedural infections and death, RFOs can lead to possible financial burdens and expenses related to frequent follow-up visits [ 1 Joint CommissionResources for managing hospital-acquired conditions. Patient Safety Link e-Zine. 2009; 5 Google Scholar ]. The rate of RFOs seem to range from 1 in 5,500 to 1 in 7,000 [ 2 Cima R.R. Kollengode A. Garnatz J. Storsveen A. Weisbrod C. Deschamps C. Incidence and characteristics of potential and actual retained foreign object events in surgical patients. J Am Coll Surg. 2008; 207: 80-87 Abstract Full Text Full Text PDF PubMed Scopus (174) Google Scholar , 3 Egorova N.N. Moskowitz A. Gelijns A. et al. Managing the prevention of retained surgical instruments: what is the value of counting?. Ann Surg. 2008; 247: 13-18 Crossref PubMed Scopus (124) Google Scholar ]. In a study conducted by Greenberg et al [ 4 Greenberg C.C. Regenbogen S.E. Lipsitz S.R. Diaz-Flores R. Gawande A.A. The frequency and significance of discrepancies in the surgical count. Ann Surg. 2008; 248: 337-341 Crossref PubMed Scopus (88) Google Scholar ], the majority of RFOs involved sponges (45%), with instruments (34%) and needles (21%) also observed.

OBJECTIVES:To determine whether gender variations in imaging and healthcare access are contributing to observed differences in renal cancer, we examine the initial events in the diagnosis of renal masses in a cohort of patients and correlate it with detailed data on imaging patterns over the same period.METHODS:A total of 308 patients diagnosed with a renal mass over 11 years were reviewed. Information on symptoms, imaging, diagnosing physician, demographics, and pathology was gathered. Data on imaging for 1 862 485 patients at our institution over the same period were also collected. The data were analyzed for temporal trends, gender variations, and differences between incidental and nonincidental masses.RESULTS:Females presented with smaller masses (4.8 vs 6.0 cm, P = .0064), and were less likely to have clear cell tumors (58.7% vs 63.4%, P = .049). A total of 66.9% of female and 61.1% of male cases were incidental (not significant). In both males and females, primary care physicians were the most common diagnosing physicians (47.4% and 49.6%, respectively). Gynecologic complaints were an uncommon cause of diagnosis for women (5.3%). Computerized tomography was the most common diagnosing modality for both males and females (69.1% and 63.2%, respectively). Ultrasound as the diagnosing modality did not reach statistical significance between males and females (23.4% and 28.6%, respectively). During the 11- year period, women underwent more imaging studies overall than men (19.7% difference), but the difference was lower when only considering studies that can diagnose renal masses (6.4% difference).CONCLUSIONS:Gender variations in imaging rates and presentation for obstetrics/gynecology concerns by females did not lead to a significant difference in incidental diagnosis and do not appear adequate to explain gender differences in renal cancer presentation.

OBJECTIVE:The educational objectives of this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of the imaging of diffuse idiopathic skeletal hyperostosis (DISH), with emphasis on acute spinal fractures.CONCLUSION:Understanding the pathomechanics of the fractures in the ankylosed spine is important in the differentiation of the acute spinal fractures in DISH and ankylosing spondylitis. This article emphasizes the imaging features of spinal DISH and acute spinal fractures in DISH, distinguishing them specifically from those in ankylosing spondylitis.

Objective. The purpose of this study was to determine the utility of sonography and sonoarthrography in evaluation of dorsal bands of the scapholunate ligament (SLL), lunotriquetral ligament (LTL), and triangular fibrocartilage (TFC) disk in correlation with arthrography and magnetic resonance arthrography (MRA). Methods. High-resolution sonography of the SLL, LTL, and TFC disk was performed on symptomatic wrists in 16 patients referred by a hand surgeon for MRA of the symptomatic wrists. All patients then underwent arthrography and an MRA study of the same wrist. After MRA, sonography was repeated. The imaging findings of these different techniques were then compared. Four patients (25%) underwent surgery of their wrists. In these 4 patients, the surgical and imaging findings were correlated. Results. For the SLL, the results were concordant for all imaging modalities in 15 patients (93.75%) and partially concordant in 1 (6.25%). For the LTL, the results were concordant for all imaging modalities in 12 patients (75%), partially concordant in 3 (18.75%), and discordant in 1 (6.25%). For the TFC disk, the results were concordant for all imaging modalities in 13 patients (81.25%), partially concordant in 2 (12.5%), and discordant in 1 (6.25%). The arthroscopic and imaging findings were concordant for 3 SLLs, 3 LTLs, and 3 TFC disks. Conclusions. Our preliminary results are encouraging. Sonography may be used at least as a screening imaging modality in evaluation of the SLL and TFC disk. Sonoarthrography improves evaluation of the LTL.

This review article provides an update on multimodality imaging characteristics of Ewing sarcoma family tumors. Pathology of this tumor and current trends in medical and surgical treatment are briefly discussed.

Objective To correlate the amount of bone marrow edema (BME) calculated by magnetic resonance imaging(MRI) with clinical findings, histopathology, and radiographic findings, in patients with advanced hip osteoarthritis(OA).Materials and methods The study was approved by The Institutional Human Subject Protection Committee. Coronal MRI of hips was acquired in 19 patients who underwent hip replacement. A spin echo (SE) sequence with four echoes and separate fast spin echo (FSE) proton density (PD)-weighted SE sequences of fat (F) and water (W) were acquired with water and fat suppression, respectively. T2 and water:fat ratio calculations were made for the outlined regions of interest. The calculated MRI values were correlated with the clinical, radiographic, and histopathologic findings.Results Analyses of variance were done on the MRI data for W/(W + F) and for T2 values (total and focal values) for the symptomatic and contralateral hips. The values were significantly higher in the study group. Statistically significant correlations were found between pain and total W/(W + F), pain and focal T2 values, and the number of microfractures and calculated BME for the focal W/(W + F) in the proximal femora. Statistically significant correlations were found between the radiographic findings and MRI values for total W/(W + F), focal W/(W + F) and focal T2 and among the radiographic findings, pain, and hip movement. On histopathology, only a small amount of BME was seen in eight proximal femora.Conclusion The amount of BME in the OA hip, as measured by MRI, correlates with the severity of pain, radiographic findings, and number of microfractures.

This review article provides an update on multimodality imaging characteristics of Ewing sarcoma family tumors. Pathology of this tumor and current trends in medical and surgical treatment are briefly discussed.

Granulocyte colony–stimulating factor (GCSF), often used as an adjunct to chemotherapy, can pose a dilemma in differentiating the associated bone marrow changes from metastatic disease on magnetic resonance imaging. The phenomenon has been previously reported in children undergoing treatment for primary musculoskeletal malignancies [1, 2]. We present a case of GCSF-induced marrow reconversion simulating neuroblastoma metastases on MR imaging. An interesting observation in our case was intense abnormal signal in a pattern of metaphyseal bands, which, to our knowledge, was not previously reported in the English literature to be associated with GCSF-induced marrow reconversion.

On-call and late-evening duties have increased dramatically for radiologists, be they in private practice, at academic medical centers, or at state or federal government health care facilities. Most busy medical centers in North America require around-the-clock radiology interpretations for emergent or urgent patients, particularly if they are level 1 trauma centers. Coverage by attending radiologists around the clock is expensive and difficult to implement. In this study, an e-mail questionnaire was sent to 83 members of the Society of Chairmen of Academic Radiology Departments concerning general radiologists' on-call and after-hours duties. Detailed replies were received from 29 academic medical centers, all of which were university owned or affiliated. There was complex variation on how academic radiology departments approached their after-hours commitments, but only 10% of academic institutions (3 of 29) answering the survey had 24-hour in-house coverage by general radiologists. Coverage by attending radiologists around the clock at academic medical centers is not the current standard of practice at most academic medical centers.