Introduction
- Charles P. Hannon, BS
- Niall A. Smyth, MD
- Christopher D. Murawski, BS
- John G. Kennedy, MD, FRCS
- Niall A. Smyth, MD
Epidemiology
- •
Ankle impingement is one of the more common challenges faced by the orthopedic foot and ankle surgeon.
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Ankle impingement is a pathology defined as the entrapment of osseous and/or soft tissue overgrowth that leads to pain and decreased range of motion.
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Although the exact incidence of ankle impingement syndromes is unknown, it is commonly associated with overuse injuries and can also present with chronic ankle sprains.
- •
Current literature on ankle impingement is described by its location in three anatomically distinct regions: anterolateral, anteromedial, and posterior. This chapter introduces each of the three ankle impingement syndromes.
Anterior Ankle Impingement: Anteromedial and Anterolateral
- •
Anterior ankle impingement is a common condition seen in many athletes, particularly soccer players, dancers, gymnasts, and cross-country runners.
- •
Ballet dancers are prone to anterior ankle impingement with repetitive microtrauma in the forced dorsiflexion position while in the plié or demi-plié positions.
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It is also commonly found in patients who suffer recurring trauma to the anterolateral aspect of the ankle either as a result of inversion injuries or repetitive dorsiflexion.
- •
Anterior ankle impingement is further discussed in the literature by its location: anteromedial and anterolateral.
Posterior Ankle Impingement
- •
Posterior ankle impingement is a relatively common syndrome found in many athletes, particularly dancers, downhill runners, and soccer players.
- •
It is typically identified as a chronic injury owing to forced plantarflexion that can result in one of several pathologies.
- •
It may be described as os trigonum syndrome, posterior block, or talar compression syndrome.
Pathophysiology
Intrinsic Factors
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In general, any intrinsic factors that are associated with ankle sprains may predispose to ankle impingement. These include:
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Increased body weight
- •
Preexisting ankle ligament laxity
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Ankle flexion strength asymmetry
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Poor proprioception
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Decreased physical conditioning
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Younger age
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Previous ankle sprain
- •
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The most common form of posterior impingement is related to the os trigonum.
- •
The os trigonum is a congenital anomaly that forms where the talar body and lateral tubercle (Stieda process) does not fuse, and is found in 2.3% of the population.
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The presence of an os trigonum predisposes a patient to posterior ankle impingement.
Extrinsic Factors
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In general, any extrinsic factors that are associated with ankle sprains may contribute to ankle impingement. These include:
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Increase in shoe heel height.
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Participation in athletic activity.
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Regarding athletic activity, participation in competitive play leads to increased risk versus noncompetitive training.
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Participation in contact sports versus non-contact sports
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Use of nonbreakaway bases in baseball and softball
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Traumatic Factors
Anteromedial Ankle Impingement
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The exact cause of anteromedial ankle impingement is currently undefined, but several theories have been proposed including:
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Repetitive capsular traction during hyperplantarflexion movements.
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Inversion ankle sprain, including the entrapment and/or tearing of the anteromedial joint capsule and impaction between the medial malleolus and medial facet of the talus.
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Repetitive dorsiflexion.
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Anterolateral Ankle Impingement
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Commonly associated with an ankle inversion injury with concurrent damage to the lateral ligament complex.
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Recurrent instability and associated microtrauma may cause soft tissue and intra-articular hemorrhage, reactive hyperplasia, and scarring.
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Symptoms of anterolateral ankle impingement may be reproduced with compression of the abnormal anterolateral soft tissue during eversion or dorsiflexion.
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In severe cases, the soft tissue may be molded within the anterolateral recess to form a reactive hyalinized connective tissue mass termed the meniscoid lesion.
Posterior Ankle Impingement
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Posterior ankle impingement is commonly associated with repetitive traumatic injuries to the ankle.
- •
During plantarflexion pain is caused by either the compression of bony anomalies and/or soft tissue such as scar tissue, posterior ankle ligaments or posterior joint capsule between the posterior aspect of the distal tibia and calcaneal bone or a microenvironment of the os trigonum or an avulsion fracture fragment.
- •
Loose bodies or avulsion fractures of the posterior tibiotalar ligament (Cedell fracture) have been described as a cause of posterior impingement syndrome.
Classic Pathological Findings
Anteromedial Ankle Impingement
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Arthroscopic evaluation may reveal soft tissue synovial hyperplasia at the anteromedial aspect of the ankle ( Figure 40-1 ).
FIGURE 40-1
Soft tissue synovial hyperplasia at the anteromedial aspect of the ankle.
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A majority of patients also have anteromedial tibial osteophytes and/or anteromedial talar osteophytes.
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In some cases, superficial fibers of the deltoid ligament may also be impinged during arthroscopic examination.
Anterolateral Ankle Impingement
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Arthroscopic evaluation demonstrates that patients may have hypertrophied, inflamed synovium that is hemorrhagic with a firm elastic consistency.
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Anterior tibial and/or talar osteophytes may also be evident.
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Evaluation of the cartilage may note degenerative and fibrotic changes.
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Patients may also present with adhesive bands of scar tissue similar to meniscoid lesions in the lateral gutter.
Posterior Ankle Impingement
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During arthroscopic evaluation, the patient should be placed in plantarflexion to view the impingement.
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In plantarflexion the patient may have compression of bony anomalies and/or soft tissue such as scar tissue, posterior ankle ligaments or posterior joint capsule between the posterior aspect of the distal tibia and calcaneal bone.
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An os trigonum or avulsion fractures may also be evident on arthroscopic evaluation.
Clinical Presentation
History
Anteromedial Ankle Impingement
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Patients with anteromedial ankle impingement often present with chronic ankle pain localized to the anteromedial aspect of the joint that is often exacerbated by activity or dorsiflexion motions such as running, jumping, or kicking a ball.
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Pain can typically be replicated with forced dorsiflexion of the ankle and pressing in the soft spot just medial to the anterior tibial tendon.
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Patients may also present with a history of ankle inversion injuries or ankle trauma.
Anterolateral Ankle Impingement
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Patients typically present with a history of anterolateral ankle pain and swelling exacerbated by activity.
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Patients may describe a history of ankle inversion injuries or ankle trauma.
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Patients may complain of a popping or snapping sensation in the joint during activity.
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Symptoms are often exacerbated by activity, such as running, jumping, or kicking a ball.
Posterior Ankle Impingement
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Patients with posterior ankle impingement often present with chronic ankle pain in the posterior aspect of their ankle that is exacerbated by activity, such as running or jumping, and plantarflexing the ankle.
- •
Patients often describe a history of a hyperplantarflexion ankle injury.
Physical Examination
Abnormal Findings: Anteromedial Ankle Impingement
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Patients often present with restricted dorsiflexion and inversion associated with soft tissue thickening of the anteromedial compartment.
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Palpation over the anteromedial ankle joint and dorsiflexing the ankle may reproduce symptoms.
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Anteromedial bony spurs may be palpable.
Abnormal Findings: Anterolateral Ankle Impingement
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Patients are typically tender upon palpation along the anterolateral aspect of the ankle.
- •
This pain is often reproduced at extreme passive dorsiflexion.
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A painful mass may be palpable in the region of the anterolateral gutter.
- •
Exacerbation of symptoms may be caused by single leg squatting and ankle eversion or dorsiflexion.
Abnormal Findings: Posterior Ankle Impingement
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Patients are typically tender upon palpation along the posterior aspect of the ankle, classically medial to the Achilles tendon.
- •
Patients’ pain is worsened when placed in forced plantarflexion.
Pertinent Normal Findings
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When evaluating ankle impingement it is important to assess for functional and mechanical ankle stability by evaluating the integrity of the ligamentous structures of the ankle such as the anterior talofibular ligament, calcaneofibular ligament, and deltoid ligament for pathology.
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It is also important to rule out fractures of the ankle as well as any cartilage defects such as osteochondral lesions of the talus or tibia.
Imaging
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For ankle impingement both osseous and soft tissue pathology should be suspected.
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AP and lateral weight-bearing radiographs are useful images for assessing bony abnormalities such as os trigonum in posterior ankle impingement.
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Computed tomography allows for further delineation of osseous abnormalities with greater detail.
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However, to view soft tissue pathologies, magnetic resonance imaging is the most appropriate modality and should be used in all patients with suspected soft tissue impingement.
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Studies have suggested that MR arthrography has the greatest sensitivity and specificity for evaluating ankle impingement, but this is less preferred because of its invasive nature.
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Clinical association with imaging findings is essential because imaging features may also be seen without symptoms of ankle impingent.
Anteromedial Ankle Impingement
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The use of standard lateral and AP radiographs are often unremarkable when assessing anteromedial ankle impingement.
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An oblique anteromedial impingement view described by van Dijk et al. allows visualization of medial osteophytes at the talotibial articulation.
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The AMI view is an oblique 45° craniocaudal radiograph with 30° of external rotation of the leg ( Figure 40-2 ).
FIGURE 40-2
Oblique anteromedial impingement view.
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MRI should also be used to evaluate the extent of soft tissue hyperplasia, swelling, and impingement.
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It is important to obtain a MRI to also rule out any other potential medial ankle pathologies (discussed in the following).
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A diagnostic injection of local anesthetic may also be given into the anteromedial joint capsule and soft tissue. If symptoms are resolved with the injection, this is considered a positive test for anteromedial impingement.
Anterolateral Ankle Impingement
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AP and lateral weight-bearing radiographs are nonspecific for anterolateral ankle impingement, but should be obtained to rule out potential osseous causes of the patients symptoms (e.g., fracture).
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Axial T1-weighted or proton density–weighted images combined with sagittal T1-weighted images are the most accurate for identifying soft tissue anterolateral impingement.
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MRI findings associated with anterolateral impingement include a focal mass within the gutter or hypertrophy of soft tissue and/or synovium in the lateral gutter.
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Abnormalities of the lateral ligament complex may also be visualized.
Posterior Ankle Impingement
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In patients with posterior impingement, an anteroposterior radiograph is unlikely to show abnormalities.
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Lateral radiographs may show a prominent talar process or an os trigonum ( Figures 40-3 ). However, an os trigonum may be superimposed on the medial talar tubercle on lateral radiographs and therefore difficult to identify.
FIGURE 40-3
Prominent talar process.
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Lateral radiographs with the foot in 25° of external rotation in relation to the standard lateral radiographs may assist in viewing an os trigonum.
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CT imaging may be useful to determine the dimension, exact location, and anatomical relationship of the os trigonum or other osseous structures present.
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MRI is also important for assessing the position of the os trigonum and the presence of any other soft tissue structures that may be causing pain.
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MRI with the foot in plantarflexion may yield additional information regarding the mobility of the os trigonum and the site of impingement.
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MRI may also show whether the os trigonum has a fibrous, fibrocartilaginous or cartilaginous attachment to the talus.
Differential Diagnosis
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There are several conditions that may cause similar symptoms to anterior and posterior ankle impingement.
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Listed in the following are several pathologies that should be included in the differential diagnosis when suspecting ankle impingement.
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A thorough history, a complete physical examination, and imaging are all important modalities to confirm the diagnosis of ankle impingement.
Anteromedial Ankle Impingement
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Osteochondral lesion of the ankle
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Stress fractures
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Injuries to deltoid ligament, spring ligament, or posterior tibial tendon
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Equinus contracture
Anterolateral Ankle Impingement
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Peroneal tendon pathology
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Sinus tarsi syndrome
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Stress fractures
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Chronic ankle instability
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ATFL, CFL pathology
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Intra-articular loose bodies
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Equinus contracture
Posterior Ankle Impingement
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Achilles tendinosis
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Flexor hallucis longus tendinosis
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Tibialis posterior tendonitis
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Deltoid ligament, posterior tibial tendon pathology
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Haglund’s deformity
Treatment
Nonoperative Management
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Nonsurgical treatment for ankle impingement includes rest, cryocompression, and elevation.
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Analgesics such as nonsteroidal anti-inflammatories may also be used to reduce pain. Activities that exacerbate pain should be avoided.
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Physical therapy is also an additional nonsurgical treatment option available, to improve range of motion, proprioception, and strength.
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Physical therapy may also work to correct any motions that may contribute to the pathogenesis of the ankle impingement, such as overpronation in ballet dancers with anterior ankle impingement.
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Injections of steroids and/or local anesthetic may also be appropriate for some patients to reduce inflammation and pain.
Guidelines for Choosing Among Nonoperative Treatments
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Rest, cryocompression and elevation should be advised for all patients with ankle impingement.
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For athletes, both recreational and professional, physical therapy may be appropriate to help assist in the recovery phase and quicken the recovery time period.
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Local anesthetic and steroidal injections are intended for those patients who are limited in their activities of daily living or athletes who are unable to return to sport.
Surgical Indications
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The surgical treatment options for ankle impingement include open surgery, arthroscopy using the standard anteromedial and anterolateral portals or hindfoot arthroscopy using posterolateral and posteromedial portals.
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The indication for surgical treatment is continued pain following 4 to 6 weeks of conservative management.
Aspects of History, Demographics, or Exam Findings that Affect Choice of Treatment
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The choice to pursue surgical treatment of ankle impingement is complex and must be individualized to each patient.
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Patients who are most appropriate for surgical treatment are those who have failed conservative management, and athletes who require a rapid return to sport.
Aspects of Clinical Decision Making When Surgery Is Indicated
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When surgery is indicated, the surgeon must decide between open surgery and arthroscopy.
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It is recommended that anterior or posterior arthroscopy be utilized for treatment of ankle impingement as it has comparative outcomes to open surgical treatment with fewer complications (e.g., infection and nerve damage).
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Of note, if a particularly large osteophyte or os trigonum needs to be removed, the arthroscopic portal may need to be enlarged or converted to open.
Evidence
Multiple Choice Questions
- QUESTION 1.
What approach should be taken remove a pathological os trigonum?
- A.
Open surgery
- B.
Ankle arthroscopy using anteromedial and anterolateral portals
- C.
Ankle arthroscopy using posterolateral and anterolateral portals
- D.
Ankle arthroscopy using posterolateral and posteromedial portals.
- A.
- QUESTION 2.
Which of the following imaging modalities is most sensitive and specific for diagnosing ankle impingement, but not commonly used because of its invasiveness?
- A.
Radiographs
- B.
Computed tomography
- C.
Magnetic resonance imaging
- D.
Magnetic resonance arthrography
- A.
- QUESTION 3.
What imaging modality provides the best view for osseous causes of anteromedial ankle impingement?
- A.
Anteroposterior radiograph
- B.
Lateral radiograph
- C.
45° craniocaudal radiograph with 30° external rotation of the leg
- D.
None of the above
- A.
- QUESTION 4.
Anterior ankle impingement is most commonly found in which of these sports?
- A.
Soccer
- B.
Skiing
- C.
Hockey
- D.
Basketball
- A.
- QUESTION 5.
Which of the following should not be included in a differential diagnosis of posterior ankle impingement?
- A.
Achilles tendinosis
- B.
Flexor hallices longus tendinosis
- C.
Tibialis posterior tendinosis
- D.
Anterior tibialis tendinosis pathology
- A.
Answer Key
- QUESTION 1.
Correct answer: D (See Treatment )
- QUESTION 2.
Correct answer: D (see Imaging )
- QUESTION 3.
Correct answer: C (see anteromedial imaging)
- QUESTION 4.
Correct answer: A (see Anterior Ankle Impingement Etiology)
- QUESTION 5.
Correct answer: D (see Posterior Ankle Impingement Differential Diagnosis)
Related posts:
Epiphyseolysis and Osteochondritis
Cervical Spine Disc Injuries
Midfoot Strains and Sprains and Lisfranc Injuries
Triangular Fibrocartilage Complex Injuries
Leg Pain in the Athlete: Stress Fractures, Medial Tibial Stress Syndrome, and External Compartment Syndromes
Ulnar Collateral Ligament Injuries
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