Diagnosis and treatment of foot disease in patients with diabetes is a common clinical-radiologic challenge, particularly the differentiation of neuropathic arthropathy from osteomyelitis. Conventional clinical tests and imaging techniques have limited accuracy for evaluation of the diabetic foot. The introduction of morphologic magnetic resonance (MR) imaging in these patients has provided a qualitative leap in diagnosis. The characteristics of soft-tissue and bone marrow edema and their patterns of distribution throughout the foot allow discrimination between both entities. However, in certain scenarios, the application of MR imaging to this problem is limited because of overlapping features between the two and the coexistence of infection and neuropathic changes. Recent technical advances in MR imaging sequences have increased the capability to add functional quantitative information to structural information. Diffusion-weighted imaging is useful to determine the presence and extension of osteomyelitis. Dynamic contrast-enhanced MR imaging may help to detect differences between the vascularization patterns of neuropathic arthropathy and osteomyelitis. MR angiography (with or without contrast material) is used in clinical practice to identify candidate distal vessels for revascularization. MR neurography, and especially diffusion-tensor imaging, provides quantitative information about neural damage. These new sequences may help in assessment of the different pathophysiologic conditions that occur in the diabetic foot. The physical basis of these techniques, their limitations, and their potential applications for diabetic foot assessment are detailed in this article. The introduction of advanced MR imaging multiparametric protocols, with the aim of enhancing the overall diagnostic accuracy of MR imaging, may help in treatment decision making and lead to improved patient outcomes. © RSNA, 2017.

In the modern treatment of Charcot neuroarthropathy, beam screw fixation is an alternative to plate and screw fixation. Exposure is minimized for implantation, and this technique supports the longitudinal columns of the foot as a rigid load-sharing construct. A published data review identified a paucity of data regarding metatarsal intramedullary canal morphology relevant to beam screw fixation. The purpose of the present study was to describe metatarsal diaphyseal morphology qualitatively and quantitatively in an effort to provide data that can be used by surgeons when selecting axially based intramedullary fixation. Twenty fresh-frozen cadaveric below-the-knee specimens were obtained. The metatarsals were exposed, cleaned of soft tissue, and axially transected at the point of the narrowest external diameter. Next, a digital caliper was used to measure the size and shape of the diaphysis of the first through fourth metatarsals. The diaphyseal canal shape was categorized as round, oval, triangular, or pear. The widest distance between the endosteal cortical surfaces was measured. Triangular endosteal canals were only found in the first metatarsal, and the remainder of the metatarsal canals were largely round or oval. These data help to approximate the size of fixation needed to achieve maximal screw-endosteal purchase.

The objective of the present investigation was to examine the effect of cuboid height on the presence of plantar midfoot ulceration and the relationship of cuboid height to other commonly performed radiographic parameters during evaluation of midfoot Charcot neuroarthropathy. A retrospective analysis was performed of 68 feet in 60 subjects who met the inclusion criteria. We did not observe statistically significant differences in the presence of a plantar midfoot ulceration when considering a cuboid height threshold of 0.0 mm, 2.0 mm, -2.0 mm, or -5.0 mm nor was the cuboid height a robust predictor for the presence of plantar midfoot ulceration when considering the positive predictive value, negative predictive value, sensitivity, or specificity. We observed a significant negative association between a negative cuboid height and the presence of Sanders Type 2 deformities (76.2% of those with negative height versus 50.0% of those with positive height had type 2 deformities; p = .0036), the absence of radiographic visualization of the lateral tarsometatarsal joint (71.4% of those with negative height versus 26.9% of those with positive height had an absence of radiographic visualization; p = .005), and lower calcaneal inclination angles (6.06° versus 15.08°; p < .001). We further observed significant positive correlations between the cuboid height and the calcaneal-fifth metatarsal angle (0.655; p < .000), calcaneal inclination angle (0.591; p < .001), calcaneal-cuboid angle (0.254; p = .038), medial column height (0.264; p = .029), and first metatarsal inclination angle (0.245; p = .047). We also observed negative correlations with Meary's angle (-0.475; p < .001) and the talar declination angle (-0.387; p < .001). These findings showed a general trend toward a decreasing cuboid height and increasing sagittal plane deformity involving both the medial and the lateral columns. The results of the present investigation provide evidence against a single radiographic parameter being associated with the presence of plantar midfoot ulceration.

Bone loss and destruction due to diabetic Charcot neuroarthropathy (CN) and osteomyelitis of the foot and ankle is a challenging clinical condition when lower extremity preservation is considered. Resection and excision of osteomyelitis and associated nonviable soft tissue can lead into large osseous and soft tissue defects that will most likely need the utilization of bone grafting and subsequent arthrodesis for stability and anatomic alignment. In the diabetic population with peripheral neuropathy, osseous instability can lead to subsequent lower extremity deformity, ulceration, infection and/or amputation. This article reviews the surgical approach in the presence of diabetic CN and concomitant osteomyelitis.

Although the effect of lower extremity pathology and surgical intervention on automobile driving function has been a topic of contemporary interest, we are unaware of any analysis of the effect of lower extremity diabetic sensorimotor neuropathy on driving performance. The objective of the present case-control investigation was to assess the mean brake response time in diabetic drivers with lower extremity neuropathy compared with that of a control group and a brake response safety threshold. The driving performances of participants were evaluated using a computerized driving simulator with specific measurement of the mean brake response time and frequency of abnormally delayed brake responses. We analyzed a control group of 25 active drivers with neither diabetes nor lower extremity neuropathy and an experimental group of 25 active drivers with type 2 diabetes and lower extremity neuropathy. The experimental group demonstrated a 37.89% slower mean brake response time (0.757 ± 0.180 versus 0.549 ± 0.076 second; p < .001), with abnormally delayed responses occurring at a greater frequency (57.5% versus 3.5%; p < .001). Independent of a comparative statistical analysis, the observed mean brake response time in the experimental group was slower than the reported safety brake response threshold of 0.70 second. The results of the present investigation provide original data with respect to abnormally delayed brake responses in diabetic patients with lower extremity neuropathy and might raise the potential for impaired driving function in this population.

Milwaukee shoulder syndrome (MSS) is a rare, rapidly destructive arthropathy associated with calcium hydroxyapatite crystal deposition. This condition is a combination of rotator cuff tear, osteoarthritic changes, noninflammatory joint effusion containing crystals, synovial hyperplasia, cartilage and subchondral bone destruction, and multiple osteochondral loose bodies. This article discusses pathophysiology, clinical presentation, differential considerations, and magnetic resonance imaging findings of MSS.