Abstract/Text: Imaging procedures are routinely used to evaluate patients suspected of having musculoskeletal infection. Radiographs should be performed whenever musculoskeletal infection is suspected. Even when not diagnostic, radiographs are useful. They provide an anatomic overview of the region of interest, including pre-existing conditions that could influence the selection and interpretation of subsequent procedures. Magnetic resonance imaging (MRI) is sensitive, provides superb anatomic detail, does not use ionizing radiation, and is rapidly completed. This technique is especially valuable for septic arthritis, spinal osteomyelitis, and diabetic foot infections. Among the radionuclide procedures, three-phase bone imaging is readily available, and very accurate in unviolated bone. Labeled leukocyte imaging should be used in cases of 'complicating osteomyelitis' such as prosthetic joint infections. This test is also useful in unsuspected diabetic pedal osteomyelitis and the neuropathic joint. Gallium imaging is a useful adjunct to MIR in spinal infection. 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) will likely play an important role, especially in the evaluation of spinal infection.

Abstract/Text: Up to 25% of the diabetic population is at risk for developing a pedal ulcer. These ulcers serve as a portal of entry for osteomyelitis and overlie more than 90% of diabetic pedal osteomyelitis cases. The diagnosis of osteomyelitis often is overlooked, and imaging studies are an essential part of the evaluation. The most commonly performed radionuclide tests are bone and labeled leukocyte imaging. Focal hyperperfusion, focal hyperemia, and focal bony uptake on the 3-phase bone scan comprise the usual presentation of osteomyelitis. Many conditions to which the diabetic population with foot problems is prone, however, mimic osteomyelitis, and the test is sensitive but not specific. Consequently, the bone scan often is used as a screening test or to facilitate localization of activity on labeled leukocyte images. Because of its high sensitivity and prevalence of positive results, its value as a screening test is questionable. Investigations comparing labeled leukocyte imaging alone to labeled leukocyte plus bone imaging, demonstrate only marginal improvement for the combined study. Thus, it is time to reevaluate the role of the bone scan in diabetic foot infections. Labeled leukocyte imaging is the radionuclide procedure of choice for evaluating diabetic pedal osteomyelitis. Sensitivity and specificity range between 72% and 100%, and 67% and 98%, respectively. Although intraindividual comparisons are few, the accuracy of the test is similar, whether the leukocytes are labeled with (99m)Tc or (111)In. Labeled leukocytes accumulate in uninfected neuropathic joints, and marrow scintigraphy may be needed to determine whether infection is present. Alternatives to labeled leukocyte imaging include in vivo methods of labeling leukocytes, radiolabeled polyclonal IgG, and radiolabeled antibiotics. The results obtained have been variable and none of these agents is available in the United States. There are few data available on single-photon emission computed tomography/computed tomography. It probably will be useful in the mid and hind foot; in the distal forefoot, given the small size of the structures, its value is less certain. Data on (18)F-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography are limited and inconclusive, and further investigation is needed.

Abstract/Text: Bone and joint infections are painful for patients and frustrating for both them and their doctors. The high success rates of antimicrobial therapy in most infectious diseases have not yet been achieved in bone and joint infections owing to the physiological and anatomical characteristics of bone. The key to successful management is early diagnosis, including bone sampling for microbiological and pathological examination to allow targeted and long-lasting antimicrobial therapy. The various types of osteomyelitis require differing medical and surgical therapeutic strategies. These types include, in order of decreasing frequency: osteomyelitis secondary to a contiguous focus of infection (after trauma, surgery, or insertion of a joint prosthesis); that secondary to vascular insufficiency (in diabetic foot infections); or that of haematogenous origin. Chronic osteomyelitis is associated with avascular necrosis of bone and formation of sequestrum (dead bone), and surgical debridement is necessary for cure in addition to antibiotic therapy. By contrast, acute osteomyelitis can respond to antibiotics alone. Generally, a multidisciplinary approach is required for success, involving expertise in orthopaedic surgery, infectious diseases, and plastic surgery, as well as vascular surgery, particularly for complex cases with soft-tissue loss.

Abstract/Text: Adult osteomyelitis remains difficult to treat, with considerable morbidity and costs to the health care system. Bacteria reach bone through the bloodstream, from a contiguous focus of infection, from penetrating trauma, or from operative intervention. Bone necrosis begins early, limiting the possibility of eradicating the pathogens, and leading to a chronic condition. Appropriate treatment includes culture-directed antibiotic therapy and operative debridement of all necrotic bone and soft tissue. Treatment often involves a combination of antibiotics. Operative treatment is often staged and includes debridement, dead space management, soft tissue coverage, restoration of blood supply, and stabilization. Clinicians and patients must share a clear understanding of the goals of treatment and the difficulties that may persist after the initial course of therapy or surgical intervention. Chronic pain and recurrence of infection still remain possible even when the acute symptoms of adult osteomyelitis have resolved.

Abstract/Text: Osteomyelitis is an important cause of morbidity and mortality in children and adults. Imaging plays a crucial role in establishing a timely diagnosis and guiding early management, with the aim of reducing long-term complications. Recognition of the imaging features of osteomyelitis requires a good understanding of its pathogenesis. In this review, the key imaging findings in osteomyelitis are correlated with the underlying pathological processes. There is a particular emphasis on magnetic resonance imaging (MRI), which is the best available imaging modality owing to its high sensitivity for detecting early osteomyelitis, excellent anatomical detail and superior soft tissue resolution. However, other modalities such as nuclear medicine and computed tomography (CT) are also useful in many clinical contexts, and will also be described in this review.