Baker et al [71] analyzed 31 occult fractures involving the ankle and foot in hockey players, finding five occult fractures in the foot, all of which involved the navicular bone. Pierre-Jerome et al [72] found 79% of cuboid fractures in the diabetic population that were radiographically occult using MRI. MRI is also useful in the detection of occult fractures involving the fifth metatarsal bone (Jones fracture) and the subtalar joint [65,73]. There is no evidence in the literature supporting the routine use of contrast in the diagnosis of occult fractures. MRI has replaced bone scans in the evaluation of symptomatic accessory ossicles. MRI allows optimal visualization of the bone marrow within the ossicle and visualization of the synchondrosis. Accessory ossicles may also be associated with tendon pathology, which is also well assessed on MRI [74]. MRI allows clear demonstration of the findings often associated with posterior ankle impingement syndrome [75]. Contrast administration is not routinely performed when assessing symptomatic accessory ossicles on MRI; however, contrast within a disrupted synchondrosis may be demonstrated on MR arthrography studies [69]. US Foot Although not routinely performed, previous studies have demonstrated the role of US in the detection of occult foot fractures. On US, these can be seen as cortical irregularities and are frequently associated with soft-tissue injury in the acute or subacute setting. Wang et al [76] demonstrated 24 cases of radiographically occult ankle and foot fractures in 268 patients. Of these, foot fractures were found most frequently in the calcaneus and metatarsals, and less frequently in the navicular, cuboid, and cuneiform bones. On US, several findings have been reported in cases of painful accessory ossicles, including patients with posterior ankle impingement syndrome; however, optimal characterization of the synchondrosis is difficult on US [62].
Chronic Foot Pain. Baker et al [71] analyzed 31 occult fractures involving the ankle and foot in hockey players, finding five occult fractures in the foot, all of which involved the navicular bone. Pierre-Jerome et al [72] found 79% of cuboid fractures in the diabetic population that were radiographically occult using MRI. MRI is also useful in the detection of occult fractures involving the fifth metatarsal bone (Jones fracture) and the subtalar joint [65,73]. There is no evidence in the literature supporting the routine use of contrast in the diagnosis of occult fractures. MRI has replaced bone scans in the evaluation of symptomatic accessory ossicles. MRI allows optimal visualization of the bone marrow within the ossicle and visualization of the synchondrosis. Accessory ossicles may also be associated with tendon pathology, which is also well assessed on MRI [74]. MRI allows clear demonstration of the findings often associated with posterior ankle impingement syndrome [75]. Contrast administration is not routinely performed when assessing symptomatic accessory ossicles on MRI; however, contrast within a disrupted synchondrosis may be demonstrated on MR arthrography studies [69]. US Foot Although not routinely performed, previous studies have demonstrated the role of US in the detection of occult foot fractures. On US, these can be seen as cortical irregularities and are frequently associated with soft-tissue injury in the acute or subacute setting. Wang et al [76] demonstrated 24 cases of radiographically occult ankle and foot fractures in 268 patients. Of these, foot fractures were found most frequently in the calcaneus and metatarsals, and less frequently in the navicular, cuboid, and cuneiform bones. On US, several findings have been reported in cases of painful accessory ossicles, including patients with posterior ankle impingement syndrome; however, optimal characterization of the synchondrosis is difficult on US [62].