Ankle and Foot 47 - Department of Radiology - University of ...

More documents

Recommendations

Info

2264 VII Imaging of the Musculoskeletal System Figure 47-73. Anderson stage IV osteochondral lesion of the talus—displaced fragment. A, Mortise radiograph; B, mortise coronal CT scan; C, mortise coronal T1-weighted MRI; D, mortise coronal T2- weighted fat-suppressed MRI. All images show the displaced fragment (arrowheads) as well as the talar donor site (short arrows). Long arrows point to marrow edema at the donor site. (Courtesy of Richard Kijowski, MD.) A B C D by joint fluid. In the partially attached fragments, the interface line was more irregular and not as bright as fluid, and at surgery this was found to represent loose granulation tissue. The stable lesions did not have increased T2 signal at their interface (Fig. 47-74). De Smet also found several patients with “focal oval or spherical lesions resembling cysts,” similar to the Anderson stage IIA lesions. These were all at the bases of unstable lesions, although at surgery these were found to be filled with loose granulation tissue rather than fluid. De Smet speculated that “these defects were traumatic cysts that were filled by the reactive tissue forming at the unstable interface.” De Smet also noted that the signal within the fragment, whether high, normal, or low on T2-weighted images, was not useful in distinguishing stable from unstable lesions (Fig. 47-75). These seminal works by Anderson and De Smet and colleagues point out the need for close communication between radiologists and orthopedic surgeons with regard to imaging and managing patients with OLT. Once the diagnosis of OLT has been established, the decision as to whether to treat the patient conservatively or surgically often comes down to determining whether the fracture is stable and has a potential for continued healing, or unstable and at risk of dislocating. • Lateral Process of Talus The lateral process of the talus (LPT) is the pointed anterolateral corner of the posterior facet of the subtalar joint, indicated by the brown arrow on gross Figure 47-4C and on sagittal CT Figure 47-7A. LPT fractures are the result of trauma, often athletic trauma. Snowboarding, in particular, is so often cited that fractures of the LPT are also referred to as snowboarder’s ankle. 48 The LPT fracture lines tend to be transversely oriented (Fig. 47-76), although vertically oriented LPT fractures can occur (Fig. 47-77). LPT fractures are often difficult to see radiographically (Fig. 47-78A) and are best imaged with CT. Because LPT fractures are typically transversely oriented in the axial plane, they are best visualized in the sagittal (Fig. 47-78B) and oblique coronal planes (Fig. 47-78C) to appreciate the size of the fracture fragment as well as the extension of the fracture line into the subtalar joint. Like OLT, LPT fractures are often diagnosed months after injury, and reports in the orthopedic literature state that “40% are missed at initial presentation.” It is incumbent on anyone who looks at radiographs of the ankle to scrutinize the LPT on all views because these fractures can be subtle and sometimes are seen only on frontal views (Fig. 47-79). Text continued on p. 2269 Ch047-A05375.indd 2264 9/9/2008 5:35:03 PM
47 Ankle and Foot 2265 47 Figure 47-74. Osteochondral lesion of the talus (OLT) in a 26-year-old with a remote history of an ankle strain, with diffuse ankle pain for the past year. Anteroposterior (A) and mortise (B) radiographs demonstrate the OLT of the medial talar dome (open arrow). MRI was obtained 1 week later. C, Mortise coronal T1-weighted image demonstrates the OLT of the medial talar dome (open arrow). D, The corresponding mortise coronal T2-weighted fatsuppressed image shows no bright signal around the OLT, indicating that it is stable. A B C D Ch047-A05375.indd 2265 9/9/2008 5:35:05 PM
Page 1 and 2:
Ken L. Schreibman Richard Bruce Ank
Page 3 and 4:
47 Ankle and Foot 2209 47 Figure 47
Page 5 and 6:
47 Ankle and Foot 2211 47 A B C Fig
Page 7 and 8: 47 Ankle and Foot 2213 47 A B C D E
Page 9 and 10: 47 Ankle and Foot 2215 47 A B C Fig
Page 11 and 12: 47 Ankle and Foot 2217 47 Figure 47
Page 13 and 14: 47 Ankle and Foot 2219 47 A B Figur
Page 21 and 22: 47 Ankle and Foot 2227 47 J K L M N
Page 27 and 28: A C E B D F Figure 47-36. Accessory
Page 37 and 38: 47 Ankle and Foot 2243 47 A Ankle/d
Page 39 and 40: 47 Ankle and Foot 2245 47 A Figure
Page 41 and 42: 47 Ankle and Foot 2247 47 ankle ten
Page 49 and 50: 47 Ankle and Foot 2255 47 A B C D F
Page 53 and 54: A B 47 Ankle and Foot 2259 47 Figur
Page 55 and 56: 47 Ankle and Foot 2261 47 A C B D F
Page 57: A B 47 Ankle and Foot 2263 47 Figur
Page 63 and 64: • Calcaneal Fractures 6,18,33 47
Page 65 and 66: 47 Ankle and Foot 2271 47 H J I LPT
Page 67 and 68: 47 Ankle and Foot 2273 47 LPT N APC
Page 69 and 70: 47 Ankle and Foot 2275 47 E F G H F
Page 73 and 74: 47 Ankle and Foot 2279 47 F G H Fig
Page 77 and 78: 47 Ankle and Foot 2283 47 LEFT LEFT
Page 81 and 82: C D 47 Ankle and Foot 2287 47 Figur
Page 85 and 86: 47 Ankle and Foot 2291 47 D E F G F
Page 87 and 88: A C B D 47 Ankle and Foot 2293 47 F
Page 89 and 90: 47 Ankle and Foot 2295 47 Tarsal tu
Page 101 and 102: A B C 47 Ankle and Foot 2307 47 Fig
Page 105 and 106: A B C D E T1 T2fs T1fs IVGd F G H F
Page 109 and 110:
A B 47 Ankle and Foot 2315 47 Figur
show all

Ankle and Foot 47 - Department of Radiology - University of ...

Create successful ePaper yourself

Delete template?

Save as template?