AJR 2003; 181:551-559
© American Roentgen Ray Society
MR Imaging of Ankle Impingement Syndromes
Luis Cerezal1,
Faustino Abascal1,
Ana Canga1,
Teresa Pereda1,
Roberto García-Valtuille1,
Luis Pérez-Carro2 and
Antonio Cruz3
1 Department of Radiology, Instituto Radiológico Cántabro,
Hospital Mompía, Mompía (Cantabria) 39108, Spain.
2 Department of Orthopaedics, Hospital de Laredo, Laredo (Cantabria) 39120,
Spain.
3 Department of Orthopaedics, Hospital Mutua Montañesa, Santander
(Cantabria) 39008, Spain.
Received September 23, 2002;
accepted after revision December 24, 2002.
Address correspondence to L. Cerezal.
Introduction
Ankle impingement syndromes are painful conditions caused by the friction
of joint tissues, which is both the cause and the effect of altered joint
biomechanics. The leading causes of impingement lesions are posttraumatic
ankle injuries, usually ankle sprains, resulting in chronic ankle pain
[1].
From anatomic and clinical viewpoints, these syndromes are classified as
anterolateral, anterior, anteromedial, posteromedial, and posterior
[1,
2].
Careful analyses of patient history and signs and symptoms at physical
examination can suggest a specific diagnosis in most patients. MR imaging and
MR arthrography are the most useful imaging methods for detecting the osseous
and soft-tissue abnormalities present in these syndromes and for ruling out
other potential causes of chronic ankle pain
[1–3].
Treatment of all impinging lesions is the same regardless of the cause. The
initial treatment is conservative, but when this fails, arthroscopic
examination is indicated to identify and resect the impinging lesion
[1,
2].
The purpose of this article is to describe the clinical, MR imaging, and MR
arthrography features of ankle impingement syndromes.
Anterolateral Impingement Syndrome
Anterolateral impingement of the ankle is a relatively uncommon cause of
chronic lateral ankle pain produced by entrapment of abnormal soft tissue in
the anterolateral gutter of the ankle
[2–4]
(Fig. 1). Anterolateral
impingement is thought to occur subsequent to relatively minor inversion
injuries of the ankle. It is estimated that approximately 3% of ankle sprains
may lead to anterolateral impingement
[1]. Such trauma may result in
tearing of the anterolateral soft tissues and ligaments without substantial
associated mechanical instability. Repeated microtrauma can result in
hypertrophied synovial tissue and fibrosis in the anterolateral gutter of the
ankle (Fig. 2A,
2B,
2C), causing pain and
mechanical impingement
[2–4].
In advanced cases, mechanical impingement may mold the tissue into a
hyalinized meniscoid lesion, which was originally described by Wolin et al.
[5].
View larger version (77K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2A. —22-year-old male soccer player with anterolateral impingement. Axial
(A and sagittal (B) T1-weighted spin-echo MR arthrograms of left
ankle show irregular soft-tissue thickening in anterolateral gutter
(arrows).
|
|
View larger version (79K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2B. —22-year-old male soccer player with anterolateral impingement. Axial
(A and sagittal (B) T1-weighted spin-echo MR arthrograms of left
ankle show irregular soft-tissue thickening in anterolateral gutter
(arrows).
|
|
Other contributing factors are thought to include hypertrophy of an
accessory fascicle of the anterior tibiofibular ligament and osseous
osteophytes
[2–4].
The accessory fascicle of the anterior tibiofibular ligament is a common
variant (Fig. 3) that was first
described by Bassett et al.
[6]. This ligament may
hypertrophy after repeated trauma, resulting in anterolateral impingement
(Fig. 4A,
4B), particularly when other
anterolateral supporting structures are compromised
[2–4,
6].
View larger version (118K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4A. —26-year-old man with anterolateral impingement syndrome. Axial
T1-weighted spin-echo MR image of right ankle shows nodular fibrous thickening
of accessory fascicle of anterior tibiofibular ligament in superior aspect of
anterolateral gutter (arrow).
|
|
View larger version (111K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4B. —26-year-old man with anterolateral impingement syndrome.
Arthroscopic image confirms diagnosis of anterolateral impingement syndrome
caused by hypertrophy of accessory fascicle of anterior tibiofibular ligament
(asterisk). L = lateral malleolus, T = talus.
|
|
The clinical diagnosis of anterolateral impingement can be established on
the basis of the combined presence of anterolateral ankle tenderness,
swelling, and pain exacerbated by single leg squatting, ankle eversion, or
dorsiflexion. However, the clinical diagnosis of anterolateral impingement is
one of exclusion
[1–4].
The MR findings of an abnormal soft-tissue mass or fibrous band in the
anterolateral ankle gutter, distinct from the anterior talofibular ligament,
suggest the diagnosis of anterolateral impingement
[2,
3]. Controversies exist about
the accuracy of MR imaging in the diagnosis of anterolateral impingement. Most
authors believe that assessment of the anterolateral recess with conventional
MR imaging is accurate only when a substantial joint effusion is present
[1–4].
MR arthrography has been proven to be an accurate technique for assessing the
presence of soft-tissue scarring in the anterolateral recess of the ankle and
elucidating its extent in patients with anterolateral impingement before
arthroscopy [2,
3] (Fig.
2A,
2B,
2C). Another MR arthrography
finding of anterolateral impingement is the absence of a recess of fluid
between the anterolateral soft tissues and the anterior surface of the fibula.
This absence may be due to the presence of adhesions and scar tissue that
prevent fluid entering the normal recess between the fibula and the joint
capsule [2,
3].
Anterior Impingement Syndrome
Anterior impingement is a relatively common cause of chronic pain in the
ankle, especially in athletes subjected to repeated stress in ankle
dorsiflexion, which is typical in soccer players
[1,
2]. This condition involves a
beaklike prominence at the anterior rim of the tibial plafond, usually
associated with a corresponding area over the opposed margin of the talus
proximal to the talar neck, well within the anterior ankle joint capsule
(Fig. 5). These osteophytes can
impinge on each other, especially with ankle dorsiflexion, and soft tissues
can become entrapped. Anterior impingement syndrome may actually limit motion
[1,
2].
View larger version (85K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5. —Drawing shows abnormal conditions that characterize anterior ankle
impingement including chondral fraying, anterior tibial and talar osteophytes
(arrows), synovitis in anterior capsular recess (asterisk),
reduction of joint space, and osteochondral loose bodies
(arrowhead).
|
|
The cause and origin of anterior impingement are uncertain, and many
factors are probably involved. It has been suggested that forced dorsiflexion
results in repeated microtraumas on the tibia and talus, leading to
microfractures of trabecular bone or periosteal hemorrhage that then heals
with the formation of new bone. Another mechanism suggested in the etiology of
these lesions is forced plantar flexion trauma that causes capsular avulsion
injury [1,
2].
Radiographs most often show anterior osteophytes, and lateral stress
radiographs obtained in maximum dorsiflexion may show physical impingement of
the osteophytes [1,
2].
MR imaging is useful in assessing the degree of cartilage damage and in
detecting bone marrow edema and synovitis in the anterior capsular recess
[2] (Fig.
6A,
6B,
6C,
6D).
View larger version (135K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6B. —25-year-old male professional soccer player with anterior
impingement. Sagittal fat-suppressed T1-weighted spin-echo MR arthrogram of
left ankle shows chondral fraying in anterior margin of tibia
(arrowhead) and anterior tibial and talar osteophytes ("kissing
lesion") (arrows) and synovitis in anterior capsular recess
(asterisk).
|
|
View larger version (98K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6C. —25-year-old male professional soccer player with anterior
impingement. Axial fat-suppressed T1-weighted spin-echo MR arthrogram reveals
dorsal talar osteophyte and focal synovitis in anterior capsular recess of
tibiotalar joint (arrow).
|
|
View larger version (97K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6D. —25-year-old male professional soccer player with anterior
impingement. Arthroscopic image shows dorsal talar neck osteophyte
(asterisk) and synovitis in anterior capsular recess of tibiotalar
joint (arrowheads). T = talus.
|
|
Anteromedial Impingement
Anteromedial impingement is an uncommon cause of chronic ankle pain that
can be a result of a meniscoid lesion, which is represented by a soft-tissue
thickening anterior to the tibiotalar ligaments
[2,
7]. The anteromedial meniscoid
lesion can appear isolated or arising from a partially torn deep deltoid
ligament. Another reported cause of anteromedial impingement is a thickened
anterior tibiotalar ligament
[1,
2,
7]. This thickened ligament or
a meniscoid lesion impinges on the anteromedial corner of the talus during
dorsiflexion of the ankle, resulting in osteophyte formation, a chondral
lesion, or both [1,
2,
7]
(Fig. 7).
View larger version (67K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7. —Drawing illustrates findings encountered in anteromedial ankle
impingement: anteromedial meniscoid lesion (arrowhead), thickened
anterior tibiotalar ligament, and chondral damage or osteophyte in
anteromedial corner of articular surface of talus (arrow).
|
|
Anteromedial impingement is rarely an isolated condition but is most
commonly associated with an inversion mechanism of injury with lateral and
medial ligamentous injury [1,
2,
7].
Conventional MR imaging has not yet been proven useful in detecting medial
impingement syndromes. MR arthrography is the imaging method of choice,
clearly defining the medial meniscoid lesion (Fig.
8A,
8B), the thickened anterior
tibiotalar ligament, and any chondral or osteochondral associated lesions
[2,
7].
View larger version (95K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8A. —35-year-old woman with anteromedial impingement syndrome confirmed
at arthroscopy. Axial T1-weighted spin-echo MR arthrogram of left ankle
reveals subtle nodular contour of anteromedial capsule (arrows). Note
normal intermediate signal adjacent to posterior tibial and flexor digitorum
tendons that corresponds to deep deltoid ligament (asterisk).
|
|
View larger version (113K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8B. —35-year-old woman with anteromedial impingement syndrome confirmed
at arthroscopy. Arthroscopic image depicts hypertrophic soft-tissue lesion in
medial talomalleolar space (arrow). M = medial malleolus, T =
talus.
|
|
Posteromedial Impingement
Posteromedial impingement is an uncommon cause of posteromedial ankle pain
after a severe ankle inversion injury in which the deep posterior fibers of
the medial deltoid ligament become crushed between the medial wall of the
talus and the medial malleolus
[8]. Initially, posteromedial
symptoms do not predominate compared with the symptoms of the lateral ligament
disruption, and they usually resolve without specific treatment. However,
inadequate healing of the contused deep posterior deltoid ligament fibers may
lead to chronic inflammation and hypertrophic fibrosis and metaplasia. In such
cases, this disorganized fibrotic scar tissue may impinge between the medial
wall of the talus and the posterior margin of the medial malleolus
[8]
(Fig. 9).
MR imaging can show the lesion, thickened soft tissues, and evidence of
bone marrow edema of both the medial talus and medial malleolus
[8] (Fig.
10A,
10B,
10C).
View larger version (151K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10A. —28-year-old man with symptoms of posteromedial impingement. Axial
T1-weighted spin-echo MR image of right ankle shows subtle hypertrophic
fibrotic tissue (arrow) deep relative to tibial posterior tendon.
|
|
View larger version (138K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10B. —28-year-old man with symptoms of posteromedial impingement. Coronal
fat-suppressed proton density–weighted MR image reveals nodular
hypointense thickening in posteromedial aspect of ankle (arrow).
|
|
Posterior Impingement
Posterior ankle impingement syndrome refers to a group of abnormal entities
that result from repetitive or acute forced plantar flexion of the foot
[9]. Different names have been
given to posterior ankle impingement syndrome, including the os trigonum
syndrome, talar compression syndrome, and posterior block of the ankle. The
mechanisms of injury have been likened to a nut in a nutcracker because the
posterior talus and surrounding soft tissues are compressed between the tibia
and the calcaneus during plantar flexion of the foot
[2,
9]
(Fig. 11). This syndrome has
been extensively described in classical ballet dancers, but it also has been
recognized in individuals who are active in sports
[2,
9].
The anatomy of the posterior aspect of the ankle is a key factor in the
occurrence of posterior ankle impingement syndrome. The more common causes are
osseous in nature, such as the os trigonum (an accessory ossicle of the
lateral tubercle of the talus that may persist unfused into adulthood in 7% of
individuals), an elongated lateral tubercle of the talus termed
"Stieda's process," a downward sloping posterior lip of the tibia,
the prominent posterior process of the calcaneus, and loose bodies
[2,
9]
(Fig. 12). Soft-tissue causes
of impingement encompass synovitis of the flexor hallucis longus tendon
sheath, the posterior synovial recess of the subtalar and tibiotalar joints,
and the posterior intermalleolar ligament.
View larger version (108K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12. —Diagrams show osseous anatomic structures involved in posterior
impingement: 1 = Stieda's process (arrows), 2 = os trigonum
(arrows), 3 = fractured lateral tubercle of talus (arrows),
4 = prominent down slope in posterior tibial articular surface
(arrowhead), 5 = calcified inflammatory tissue (arrowhead),
and 6 = prominent superior surface of calcaneal tuberosity
(arrowheads).
|
|
Posterior ankle impingement syndrome may manifest as inflammation of the
soft tissues of the posterior ankle, an osseous injury, or both (Fig.
13A,
13B,
13C). The osseous injuries
include fracture, fragmentation, and pseudoarthrosis of the os trigonum or
lateral talar tubercle. As such, posterior ankle and subtalar synovitis as
well as flexor hallucis longus tenosynovitis are soft-tissue changes
associated with posterior ankle impingement syndrome
[2,
9].
View larger version (136K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13A. —22-year-old male basketball player with posterior impingement. Axial
(A) and sagittal (B) fat-suppressed proton
density–weighted MR images of right ankle show abnormal high signal
intensity in posterior aspect of talus and in os trigonum (arrows).
Note joint effusion in posterior synovial recess of tibiotalar and subtalar
joints.
|
|
View larger version (179K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13B. —22-year-old male basketball player with posterior impingement. Axial
(A) and sagittal (B) fat-suppressed proton
density–weighted MR images of right ankle show abnormal high signal
intensity in posterior aspect of talus and in os trigonum (arrows).
Note joint effusion in posterior synovial recess of tibiotalar and subtalar
joints.
|
|
MR imaging is useful in establishing the diagnosis of posterior ankle
impingement syndrome. This modality shows abnormal signal intensity in the
lateral talar tubercle, the os trigonum, or both, consistent with bone marrow
edema that is believed to be the result of bone impaction and thus represents
bone contusions or occult fractures
[2,
9] (Figs.
14 and
15A,
15B). MR imaging also depicts
inflammatory changes in the soft tissues of the posterior ankle—namely,
the posterior synovial recess of the subtalar and tibiotalar joints and the
flexor hallucis longus tendon sheath (Fig.
14). The combined presence of bone marrow edema and posterior
ankle synovitis may suggest the diagnosis of posterior ankle impingement
[2,
9].
View larger version (135K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14. —42-year-old man with posterior impingement. Sagittal fat-suppressed
proton density–weighted MR image of right ankle shows abnormal high
signal intensity in os trigonum and posterior aspect of talus with associated
tenosynovitis of flexor hallucis longus (asterisks).
|
|
View larger version (198K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15A. —34-year-old man with posterior impingement. Sagittal T1-weighted MR
image of left ankle shows prominent lateral tubercle of talus (Stieda's
process) with low signal intensity (arrow).
|
|
View larger version (156K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15B. —34-year-old man with posterior impingement. Sagittal fat-suppressed
proton density–weighted MR image shows bone marrow high signal intensity
in Stieda's process (arrow) and in dorsal aspect of calcaneus
(arrowheads). Associated inflammation in adjacent soft tissues is
present.
|
|
Detection of an abnormal posterior intermalleolar ligament on MR imaging
requires a thickened posterior intermalleolar ligament that can readily be
separated from the surrounding posterior talofibular ligament and the
transverse inferior tibiofibular ligament
[10] (Figs.
16 and
17A,
17B).
View larger version (153K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 17A. —21-year-old woman with symptoms of posterior ankle impingement.
Coronal fat-suppressed proton density–weighted MR image of right ankle
shows poorly defined posterior intermalleolar ligament (arrow).
|
|
View larger version (124K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 17B. —21-year-old woman with symptoms of posterior ankle impingement.
Arthroscopic image of ankle reveals frayed posterior intermalleolar ligament
(asterisk). Débridement of ligament resulted in relief of
symptoms. PITF = posteroinferior tibiofibular ligament, IML = posterior
intermalleolar ligament.
|
|
Conclusion
In the appropriate clinical settings, MR imaging and MR arthrography are
useful techniques for assessing the soft-tissue and osseous disorders present
in the impingement syndromes of the ankle and for detecting other potential
causes of ankle pain.
References
- Umans H. Ankle impingement syndromes. Semin
Musculoskelet Radiol 2002;6:133
–139[Medline]
- Robinson P, White LM. Soft-tissue and osseous impingement syndromes
of the ankle: role of imaging in diagnosis and management. Radio-
Graphics 2002;22:1457
–1469[Abstract/Free Full Text]
- Robinson P, White LM, Salonen DC, Daniels TR, Ogilvie-Harris D.
Anterolateral ankle impingement: MR arthrographic assessment of the
anterolateral recess. Radiology2001; 221:186
–190[Abstract/Free Full Text]
- Rubin DA, Tishkoff NW, Britton CA, Conti SF, Towers JD.
Anterolateral soft-tissue impingement in the ankle: diagnosis using MR
imaging. AJR1997; 169:829
–835[Abstract/Free Full Text]
- Wolin I, Glassman F, Sideman S, Levinthal DH. Internal derangement
of the talofibular component of the ankle. Surg Gynecol
Obstet 1950;91:193
–200
- Bassett FH III, Gates HS III, Billys JB, Morris HB, Nikolaou PK.
Talar impingement by the anteroinferior tibiofibular ligament: a cause of
chronic pain in the ankle after inversion sprain. J Bone Joint Surg
Am 1990;72:55
–59[Abstract/Free Full Text]
- Robinson P, White LM, Salonen D, Ogilvie-Harris D. Anteromedial
impingement of the ankle: using MR arthrography to assess the anteromedial
recess. AJR2002; 178:601
–604[Abstract/Free Full Text]
- Paterson RS, Brown JN. The posteromedial impingement lesion of the
ankle: a series of six cases. Am J Sports Med2001; 29:550
–557[Abstract/Free Full Text]
- Bureau NJ, Cardinal E, Hobden R, Aubin B. Posterior ankle
impingement syndrome: MR imaging findings in seven patients.
Radiology2000; 215:497
–503[Abstract/Free Full Text]
- Fiorella D, Helms CA, Nunley JA. The MR imaging features of the
posterior intermalleolar ligament in patients with posterior impingement
syndrome of the ankle. Skeletal Radiol1999; 28:573
–576[Medline]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Introduction
Anterolateral Impingement...
