MR imaging of deltoid ligament pathologic findings and associated impingement syndromes

Abstract

Injuries of the deltoid ligament of the ankle are increasingly recognized with the widespread use of magnetic resonance (MR) imaging. The use of higher magnetic field strengths requires familiarity with the anatomic substructure of the deltoid ligament to better localize and characterize pathologic findings. Specifically, improved image resolution allows components of the superficial (tibiocalcaneal, tibionavicular, posterior superficial tibiotalar, and tibiospring ligaments) and deep (anterior tibiotalar and posterior deep tibiotalar ligaments) portions of the ligament to be evaluated separately. Awareness of the deltoid ligament substructure and associated injury patterns can guide the radiologist in defining underlying mechanical derangement, such as that seen in various impingement disorders. In this review article, the MR imaging technique for the deltoid ligament is summarized, and the normal and abnormal MR imaging appearances of various components of the deltoid ligament and associated impingement syndromes are presented.

Figure 1a

Normal deltoid ligament. (a) Coronal T1-weighted MR image shows a normal PDTL (arrow) with a striated appearance. (b) Coronal T1-weighted MR image shows a normal ATTL (thin arrow), tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), and superomedial oblique band (arrowhead). (c) Axial T1-weighted MR image shows the normal ATTL (arrow) and PDTL (arrowhead).

Figure 1b

Normal deltoid ligament. (a) Coronal T1-weighted MR image shows a normal PDTL (arrow) with a striated appearance. (b) Coronal T1-weighted MR image shows a normal ATTL (thin arrow), tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), and superomedial oblique band (arrowhead). (c) Axial T1-weighted MR image shows the normal ATTL (arrow) and PDTL (arrowhead).

Figure 1c

Normal deltoid ligament. (a) Coronal T1-weighted MR image shows a normal PDTL (arrow) with a striated appearance. (b) Coronal T1-weighted MR image shows a normal ATTL (thin arrow), tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), and superomedial oblique band (arrowhead). (c) Axial T1-weighted MR image shows the normal ATTL (arrow) and PDTL (arrowhead).

Figure 2a

Normal deltoid ligament. (a) Coronal intermediate-weighted fat-saturated MR image shows a normal ATTL with a minimal striated appearance caused by fat suppression (straight arrow), tibiocalcaneal ligament (curved arrow), and flexor retinaculum (arrowhead). (b) Coronal intermediate-weighted fat-saturated MR image shows a normal PDTL (arrow) with a striated appearance and the flexor retinaculum (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image shows the tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), superomedial oblique band (arrowhead), and fibrocartilaginous gliding zone (thin arrow).

Figure 2b

Normal deltoid ligament. (a) Coronal intermediate-weighted fat-saturated MR image shows a normal ATTL with a minimal striated appearance caused by fat suppression (straight arrow), tibiocalcaneal ligament (curved arrow), and flexor retinaculum (arrowhead). (b) Coronal intermediate-weighted fat-saturated MR image shows a normal PDTL (arrow) with a striated appearance and the flexor retinaculum (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image shows the tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), superomedial oblique band (arrowhead), and fibrocartilaginous gliding zone (thin arrow).

Figure 2c

Normal deltoid ligament. (a) Coronal intermediate-weighted fat-saturated MR image shows a normal ATTL with a minimal striated appearance caused by fat suppression (straight arrow), tibiocalcaneal ligament (curved arrow), and flexor retinaculum (arrowhead). (b) Coronal intermediate-weighted fat-saturated MR image shows a normal PDTL (arrow) with a striated appearance and the flexor retinaculum (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image shows the tibiospring ligament (*), flexor retinaculum (curved arrow), tibialis posterior tendon (thick arrow), superomedial oblique band (arrowhead), and fibrocartilaginous gliding zone (thin arrow).

Figure 3a

Acute left ankle injury and medial pain in a 45-year-old man. (a) Coronal intermediate-weighted MR image shows loss of fatty striations of the PDTL (arrow), consistent with a grade I sprain injury. (b) Coronal intermediate-weighted fat-saturated MR image shows a medial malleolar contusion and minimal hyperintensity of the PDTL (arrow). Note the grade I/II sprained tibiocalcaneal ligament (arrowhead). (c) Axial intermediate-weighted MR image shows amorphous signal intensity of both the ATTL (arrowhead) and the PDTL (arrow), in keeping with a grade I sprain.

Figure 3b

Acute left ankle injury and medial pain in a 45-year-old man. (a) Coronal intermediate-weighted MR image shows loss of fatty striations of the PDTL (arrow), consistent with a grade I sprain injury. (b) Coronal intermediate-weighted fat-saturated MR image shows a medial malleolar contusion and minimal hyperintensity of the PDTL (arrow). Note the grade I/II sprained tibiocalcaneal ligament (arrowhead). (c) Axial intermediate-weighted MR image shows amorphous signal intensity of both the ATTL (arrowhead) and the PDTL (arrow), in keeping with a grade I sprain.

Figure 3c

Acute left ankle injury and medial pain in a 45-year-old man. (a) Coronal intermediate-weighted MR image shows loss of fatty striations of the PDTL (arrow), consistent with a grade I sprain injury. (b) Coronal intermediate-weighted fat-saturated MR image shows a medial malleolar contusion and minimal hyperintensity of the PDTL (arrow). Note the grade I/II sprained tibiocalcaneal ligament (arrowhead). (c) Axial intermediate-weighted MR image shows amorphous signal intensity of both the ATTL (arrowhead) and the PDTL (arrow), in keeping with a grade I sprain.

Figure 4a

Images of a 55-year-old woman with a history of subacute ankle injury. (a) Coronal T2-weighted fat-saturated MR image shows a small osteochondral lesion of the lateral talar dome (arrow) and a grade I/II sprain of the PDTL (arrowhead). (b) Sagittal T2-weighted fat-saturated MR image shows abnormal high signal intensity in the PDTL (arrow).

Figure 4b

Images of a 55-year-old woman with a history of subacute ankle injury. (a) Coronal T2-weighted fat-saturated MR image shows a small osteochondral lesion of the lateral talar dome (arrow) and a grade I/II sprain of the PDTL (arrowhead). (b) Sagittal T2-weighted fat-saturated MR image shows abnormal high signal intensity in the PDTL (arrow).

Figure 5a

Acute ankle injury. (a) Coronal T1-weighted MR image shows amorphous signal intensity in the ATTL (curved arrow) and subcutaneous edema, most prominent medially (straight arrow). (b) Coronal T2-weighted fat-saturated MR image again shows subcutaneous edema (straight arrow), a grade I sprain of the ATTL (curved arrow), and a grade II sprained hypointense tibiospring ligament (arrowhead).

Figure 5b

Acute ankle injury. (a) Coronal T1-weighted MR image shows amorphous signal intensity in the ATTL (curved arrow) and subcutaneous edema, most prominent medially (straight arrow). (b) Coronal T2-weighted fat-saturated MR image again shows subcutaneous edema (straight arrow), a grade I sprain of the ATTL (curved arrow), and a grade II sprained hypointense tibiospring ligament (arrowhead).

Figure 6a

Images of a 37-year-old man with ankle pain. (a) Coronal T2-weighted fat-saturated MR image shows a hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (b) Coronal T1-weighted MR image shows the hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (c) Axial T2-weighted fat-saturated MR image shows the hypointense tibiospring ligament (arrow).

Figure 6b

Images of a 37-year-old man with ankle pain. (a) Coronal T2-weighted fat-saturated MR image shows a hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (b) Coronal T1-weighted MR image shows the hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (c) Axial T2-weighted fat-saturated MR image shows the hypointense tibiospring ligament (arrow).

Figure 6c

Images of a 37-year-old man with ankle pain. (a) Coronal T2-weighted fat-saturated MR image shows a hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (b) Coronal T1-weighted MR image shows the hypointense tibiospring ligament (arrow) and superomedial oblique band (arrowhead). (c) Axial T2-weighted fat-saturated MR image shows the hypointense tibiospring ligament (arrow).

Figure 7a

Acute left ankle injury with grade II deltoid ligament sprain. (a) Coronal T1-weighted MR image shows loss of normal striations in the deep deltoid ligament (arrow). (b) Coronal T2-weighted fat-saturated MR image helps confirm a grade II tear of the ATTL (short thin arrow), calcaneofibular ligament tear (thick straight arrow), anterior talofibular ligament tear (arrowhead), medial malleolar contusion (long thin arrow), and talar contusion (curved arrow). (c) Axial T1-weighted MR image shows thickening and loss of striations of the deep deltoid ligament (arrow). (d) Axial T2-weighted fat-saturated MR image shows a grade II deep deltoid ligament tear (arrow) and anterior talofibular ligament tear (arrowhead).

Figure 7b

Acute left ankle injury with grade II deltoid ligament sprain. (a) Coronal T1-weighted MR image shows loss of normal striations in the deep deltoid ligament (arrow). (b) Coronal T2-weighted fat-saturated MR image helps confirm a grade II tear of the ATTL (short thin arrow), calcaneofibular ligament tear (thick straight arrow), anterior talofibular ligament tear (arrowhead), medial malleolar contusion (long thin arrow), and talar contusion (curved arrow). (c) Axial T1-weighted MR image shows thickening and loss of striations of the deep deltoid ligament (arrow). (d) Axial T2-weighted fat-saturated MR image shows a grade II deep deltoid ligament tear (arrow) and anterior talofibular ligament tear (arrowhead).

Figure 7c

Acute left ankle injury with grade II deltoid ligament sprain. (a) Coronal T1-weighted MR image shows loss of normal striations in the deep deltoid ligament (arrow). (b) Coronal T2-weighted fat-saturated MR image helps confirm a grade II tear of the ATTL (short thin arrow), calcaneofibular ligament tear (thick straight arrow), anterior talofibular ligament tear (arrowhead), medial malleolar contusion (long thin arrow), and talar contusion (curved arrow). (c) Axial T1-weighted MR image shows thickening and loss of striations of the deep deltoid ligament (arrow). (d) Axial T2-weighted fat-saturated MR image shows a grade II deep deltoid ligament tear (arrow) and anterior talofibular ligament tear (arrowhead).

Figure 7d

Acute left ankle injury with grade II deltoid ligament sprain. (a) Coronal T1-weighted MR image shows loss of normal striations in the deep deltoid ligament (arrow). (b) Coronal T2-weighted fat-saturated MR image helps confirm a grade II tear of the ATTL (short thin arrow), calcaneofibular ligament tear (thick straight arrow), anterior talofibular ligament tear (arrowhead), medial malleolar contusion (long thin arrow), and talar contusion (curved arrow). (c) Axial T1-weighted MR image shows thickening and loss of striations of the deep deltoid ligament (arrow). (d) Axial T2-weighted fat-saturated MR image shows a grade II deep deltoid ligament tear (arrow) and anterior talofibular ligament tear (arrowhead).

Figure 8a

Images of a 55-year-old man with chronic ankle pain. (a) Coronal intermediate-weighted MR image shows posterolateral talar subluxation and tilt, with tibiotalar spurs in the medial clear space (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows tibiotalar osteoarthritis with subchondral edema (circled area). Also note amorphous signal intensity of the ATTL (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image obtained posterior to b shows thickened and remodeled tibiocalcaneal ligament (arrow) related to the chronic/old injury.

Figure 8b

Images of a 55-year-old man with chronic ankle pain. (a) Coronal intermediate-weighted MR image shows posterolateral talar subluxation and tilt, with tibiotalar spurs in the medial clear space (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows tibiotalar osteoarthritis with subchondral edema (circled area). Also note amorphous signal intensity of the ATTL (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image obtained posterior to b shows thickened and remodeled tibiocalcaneal ligament (arrow) related to the chronic/old injury.

Figure 8c

Images of a 55-year-old man with chronic ankle pain. (a) Coronal intermediate-weighted MR image shows posterolateral talar subluxation and tilt, with tibiotalar spurs in the medial clear space (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows tibiotalar osteoarthritis with subchondral edema (circled area). Also note amorphous signal intensity of the ATTL (arrowhead). (c) Coronal intermediate-weighted fat-saturated MR image obtained posterior to b shows thickened and remodeled tibiocalcaneal ligament (arrow) related to the chronic/old injury.

Figure 9a

Images of a 45-year-old woman with medial ankle pain and findings of an old partial tear of the deltoid ligament and tibialis posterior dysfunction. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity of the ATTL (straight arrow) and a mildly thickened tibiospring ligament (curved arrow) and superomedial oblique band (arrowhead). (c) Sagittal intermediate-weighted MR image shows amorphous signal intensity of the ATTL (arrow) and PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows a thickened tibialis posterior tendon with mild tenosynovitis (arrowhead) and a hypointense anterior talofibular ligament related to an old partial tear (arrow).

Figure 9b

Images of a 45-year-old woman with medial ankle pain and findings of an old partial tear of the deltoid ligament and tibialis posterior dysfunction. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity of the ATTL (straight arrow) and a mildly thickened tibiospring ligament (curved arrow) and superomedial oblique band (arrowhead). (c) Sagittal intermediate-weighted MR image shows amorphous signal intensity of the ATTL (arrow) and PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows a thickened tibialis posterior tendon with mild tenosynovitis (arrowhead) and a hypointense anterior talofibular ligament related to an old partial tear (arrow).

Figure 9c

Images of a 45-year-old woman with medial ankle pain and findings of an old partial tear of the deltoid ligament and tibialis posterior dysfunction. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity of the ATTL (straight arrow) and a mildly thickened tibiospring ligament (curved arrow) and superomedial oblique band (arrowhead). (c) Sagittal intermediate-weighted MR image shows amorphous signal intensity of the ATTL (arrow) and PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows a thickened tibialis posterior tendon with mild tenosynovitis (arrowhead) and a hypointense anterior talofibular ligament related to an old partial tear (arrow).

Figure 9d

Images of a 45-year-old woman with medial ankle pain and findings of an old partial tear of the deltoid ligament and tibialis posterior dysfunction. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity of the ATTL (straight arrow) and a mildly thickened tibiospring ligament (curved arrow) and superomedial oblique band (arrowhead). (c) Sagittal intermediate-weighted MR image shows amorphous signal intensity of the ATTL (arrow) and PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows a thickened tibialis posterior tendon with mild tenosynovitis (arrowhead) and a hypointense anterior talofibular ligament related to an old partial tear (arrow).

Figure 10a

Anteromedial ankle impingement in a 55-year-old woman with previous ankle injuries and recurrent medial ankle pain. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL with heterotopic bone formation (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the ATTL and heterotopic bone formation (arrow). (c) Axial T1-weighted MR image helps confirm involvement of the ATTL (arrow) and shows a normal-appearing PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows fibrosis and synovial proliferation of the ATTL (arrow).

Figure 10b

Anteromedial ankle impingement in a 55-year-old woman with previous ankle injuries and recurrent medial ankle pain. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL with heterotopic bone formation (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the ATTL and heterotopic bone formation (arrow). (c) Axial T1-weighted MR image helps confirm involvement of the ATTL (arrow) and shows a normal-appearing PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows fibrosis and synovial proliferation of the ATTL (arrow).

Figure 10c

Anteromedial ankle impingement in a 55-year-old woman with previous ankle injuries and recurrent medial ankle pain. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL with heterotopic bone formation (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the ATTL and heterotopic bone formation (arrow). (c) Axial T1-weighted MR image helps confirm involvement of the ATTL (arrow) and shows a normal-appearing PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows fibrosis and synovial proliferation of the ATTL (arrow).

Figure 10d

Anteromedial ankle impingement in a 55-year-old woman with previous ankle injuries and recurrent medial ankle pain. (a) Coronal intermediate-weighted MR image shows amorphous signal intensity in the ATTL with heterotopic bone formation (arrow). (b) Coronal intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the ATTL and heterotopic bone formation (arrow). (c) Axial T1-weighted MR image helps confirm involvement of the ATTL (arrow) and shows a normal-appearing PDTL (arrowhead). (d) Axial intermediate-weighted fat-saturated MR image shows fibrosis and synovial proliferation of the ATTL (arrow).

Figure 11a

Predominantly anteromedial impingement in a 39-year-old man with recalcitrant medial ankle pain and instability. (a) Anteroposterior radiograph of the ankle shows heterotopic bone formation (arrow) in the medial tibiotalar space. (b) Coronal intermediate-weighted MR image shows heterotopic bone formation in relation to the ATTL (arrow), with amorphous signal intensity. (c) Coronal T2-weighted fat-saturated MR image shows abnormal high signal intensity (arrow) in the region of the ATTL that is due to synovial proliferation and fibrosis. (d) Axial intermediate-weighted MR image shows amorphous signal intensity in both the ATTL and the PDTL, with heterotopic bone formation (arrow) in relation to the ATTL.

Figure 11b

Predominantly anteromedial impingement in a 39-year-old man with recalcitrant medial ankle pain and instability. (a) Anteroposterior radiograph of the ankle shows heterotopic bone formation (arrow) in the medial tibiotalar space. (b) Coronal intermediate-weighted MR image shows heterotopic bone formation in relation to the ATTL (arrow), with amorphous signal intensity. (c) Coronal T2-weighted fat-saturated MR image shows abnormal high signal intensity (arrow) in the region of the ATTL that is due to synovial proliferation and fibrosis. (d) Axial intermediate-weighted MR image shows amorphous signal intensity in both the ATTL and the PDTL, with heterotopic bone formation (arrow) in relation to the ATTL.

Figure 11c

Predominantly anteromedial impingement in a 39-year-old man with recalcitrant medial ankle pain and instability. (a) Anteroposterior radiograph of the ankle shows heterotopic bone formation (arrow) in the medial tibiotalar space. (b) Coronal intermediate-weighted MR image shows heterotopic bone formation in relation to the ATTL (arrow), with amorphous signal intensity. (c) Coronal T2-weighted fat-saturated MR image shows abnormal high signal intensity (arrow) in the region of the ATTL that is due to synovial proliferation and fibrosis. (d) Axial intermediate-weighted MR image shows amorphous signal intensity in both the ATTL and the PDTL, with heterotopic bone formation (arrow) in relation to the ATTL.

Figure 11d

Predominantly anteromedial impingement in a 39-year-old man with recalcitrant medial ankle pain and instability. (a) Anteroposterior radiograph of the ankle shows heterotopic bone formation (arrow) in the medial tibiotalar space. (b) Coronal intermediate-weighted MR image shows heterotopic bone formation in relation to the ATTL (arrow), with amorphous signal intensity. (c) Coronal T2-weighted fat-saturated MR image shows abnormal high signal intensity (arrow) in the region of the ATTL that is due to synovial proliferation and fibrosis. (d) Axial intermediate-weighted MR image shows amorphous signal intensity in both the ATTL and the PDTL, with heterotopic bone formation (arrow) in relation to the ATTL.

Figure 12a

Posteromedial impingement in a 46-year-old man with previous ankle injury and posteromedial pain. (a) Coronal intermediate-weighted MR image shows a normal striated appearance of the ATTL (arrow). (b) Axial intermediate-weighted MR image shows amorphous signal intensity in the PDTL, with heterotopic bone formation in the posterior and central medial clear space (thin arrow). Also note the osteochondral lesion of the posterior medial talus (thick arrow). (c) Axial intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the PDTL (thin arrow) and the osteochondral lesion of the posterior medial talus (thick arrow). (d) Axial intermediate-weighted MR image obtained caudad to b shows similar findings: amorphous signal intensity in the PDTL and heterotopic bone formation in the medial clear space (arrow). (e) Axial intermediate-weighted fat-saturated MR image obtained caudad to c shows abnormal high signal intensity in the PDTL (arrow), resulting from synovial proliferation and fibrocartilaginous metaplasia.

Figure 12b

Posteromedial impingement in a 46-year-old man with previous ankle injury and posteromedial pain. (a) Coronal intermediate-weighted MR image shows a normal striated appearance of the ATTL (arrow). (b) Axial intermediate-weighted MR image shows amorphous signal intensity in the PDTL, with heterotopic bone formation in the posterior and central medial clear space (thin arrow). Also note the osteochondral lesion of the posterior medial talus (thick arrow). (c) Axial intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the PDTL (thin arrow) and the osteochondral lesion of the posterior medial talus (thick arrow). (d) Axial intermediate-weighted MR image obtained caudad to b shows similar findings: amorphous signal intensity in the PDTL and heterotopic bone formation in the medial clear space (arrow). (e) Axial intermediate-weighted fat-saturated MR image obtained caudad to c shows abnormal high signal intensity in the PDTL (arrow), resulting from synovial proliferation and fibrocartilaginous metaplasia.

Figure 12c

Posteromedial impingement in a 46-year-old man with previous ankle injury and posteromedial pain. (a) Coronal intermediate-weighted MR image shows a normal striated appearance of the ATTL (arrow). (b) Axial intermediate-weighted MR image shows amorphous signal intensity in the PDTL, with heterotopic bone formation in the posterior and central medial clear space (thin arrow). Also note the osteochondral lesion of the posterior medial talus (thick arrow). (c) Axial intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the PDTL (thin arrow) and the osteochondral lesion of the posterior medial talus (thick arrow). (d) Axial intermediate-weighted MR image obtained caudad to b shows similar findings: amorphous signal intensity in the PDTL and heterotopic bone formation in the medial clear space (arrow). (e) Axial intermediate-weighted fat-saturated MR image obtained caudad to c shows abnormal high signal intensity in the PDTL (arrow), resulting from synovial proliferation and fibrocartilaginous metaplasia.

Figure 12d

Posteromedial impingement in a 46-year-old man with previous ankle injury and posteromedial pain. (a) Coronal intermediate-weighted MR image shows a normal striated appearance of the ATTL (arrow). (b) Axial intermediate-weighted MR image shows amorphous signal intensity in the PDTL, with heterotopic bone formation in the posterior and central medial clear space (thin arrow). Also note the osteochondral lesion of the posterior medial talus (thick arrow). (c) Axial intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the PDTL (thin arrow) and the osteochondral lesion of the posterior medial talus (thick arrow). (d) Axial intermediate-weighted MR image obtained caudad to b shows similar findings: amorphous signal intensity in the PDTL and heterotopic bone formation in the medial clear space (arrow). (e) Axial intermediate-weighted fat-saturated MR image obtained caudad to c shows abnormal high signal intensity in the PDTL (arrow), resulting from synovial proliferation and fibrocartilaginous metaplasia.

Figure 12e

Posteromedial impingement in a 46-year-old man with previous ankle injury and posteromedial pain. (a) Coronal intermediate-weighted MR image shows a normal striated appearance of the ATTL (arrow). (b) Axial intermediate-weighted MR image shows amorphous signal intensity in the PDTL, with heterotopic bone formation in the posterior and central medial clear space (thin arrow). Also note the osteochondral lesion of the posterior medial talus (thick arrow). (c) Axial intermediate-weighted fat-saturated MR image shows amorphous signal intensity in the PDTL (thin arrow) and the osteochondral lesion of the posterior medial talus (thick arrow). (d) Axial intermediate-weighted MR image obtained caudad to b shows similar findings: amorphous signal intensity in the PDTL and heterotopic bone formation in the medial clear space (arrow). (e) Axial intermediate-weighted fat-saturated MR image obtained caudad to c shows abnormal high signal intensity in the PDTL (arrow), resulting from synovial proliferation and fibrocartilaginous metaplasia.