Posterior ankle impingement syndrome is a clinical disorder characterized by posterior ankle pain that occurs in forced plantar flexion. The pain may be acute as a result of trauma or chronic from repetitive stress. It can take up to 12 weeks to fully recover from posterior ankle impingement – whether you have surgical or non-surgical treatment.
Posterior ankle impingement results from compression of structures posterior to the tibiotalar and talocalcaneal articulations during terminal plantar flexion. Pain is caused by mechanical obstruction due to osteophytes and/or entrapment of various soft tissue structures due to inflammation, scarring, or hypermobility.
Posterior ankle impingement syndrome is a clinical disorder characterized by posterior ankle pain that occurs in forced plantar flexion. The pain may be acute as a result of trauma or chronic from repetitive stress. Pathology of the os trigonum-talar process is the most common cause of this syndrome, but it also may result from flexor hallucis longus tenosynovitis, ankle osteochondritis, subtalar joint disease, and fracture. Patients usually report chronic or recurrent posterior ankle pain caused or exacerbated by forced plantarflexion or push-off maneuvers, such as may occur during dancing, kicking, or downhill running. Diagnosis of posterior ankle impingement syndrome is based primarily on the clinical history and physical examination. Radiography, scintigraphy, computed tomography, and magnetic resonance imaging depict associated bone and soft-tissue abnormalities. Symptoms typically improve with nonsurgical management, but surgery may be required in refractory cases.
Other Names
- Posterior Ankle Impingement Syndrome (PAIS)
- Posterior block of the ankle
- Posterior triangle pain
- Talar compression syndrome
- Os trigonum syndrome
- Os trigonum impingement
- Posterior tibiotalar impingement syndrome
- Nutcracker-type syndrome
Pathophysiology
- Definition
- There is a lack of consensus regarding the definition of PAIS
- Generally considered to be the clinical disorder characterized by posterior ankle pain in forced plantar flexion.
- It has been referred to as “soft tissue impingement” or “bony impingement” occurring within the anatomic interval between the posterior tibial articular surface and the calcaneus
- Diagnosis
- Challenging due to the wide variety of causes of posterior ankle pain
- Anatomic structures are deeply positioned, which makes physical exam limited
- Must consider age, sex, mechanism, prior treatments, associated conditions
Causes
Osseous Lesions
- Steeda process
- Os trigonum
- Osteoarthritis with osteophytes
- Osteochondral lesion
- Can occur in the tibiotalar space or subtalar space
- Often missed or delayed in up to 81% of unexplained chronic ankle pain (need reference)
- Patients often complain of swelling, pain, and mechanical symptoms including locking, catching
- Loose bodies
- Chondromatosis
- Subtalar coalition
- Synchondrosis injury to Os Trigonum
- Prominent Calcaneus posterior process
Soft Tissue Lesions
- Flexor Hallucis Longus Tenosynovitis
- Seen in runners, tennis players, and those involved in repetitive push-off maneuvers, such as ballet dancers
- Typically begins insidiously
- Pain at the posteromedial ankle can radiate along with the worse, worse with manipulation of hallux
- Synovitis
- Impingement of the joint capsule
- Posterior capsuloligamentous injury
- Impingement of the anomalous muscles
- Calcified inflammatory tissue
Pathoanatomy
- Posterior region of ankle
- Includes soft tissue structures between Ankle Joint (Tibiotalar Joint) and Calcaneus
- Superior border: horizontal line 4 cm above the tip of the malleolus
- Inferior border: curved line 4 cm below the lateral malleolus
- Achilles Tendon is the central axis
- Os Trigonum
- Secondary ossification center of the Talus
- Mineralizes between age 7 and 13, fuses within 1 year, forms the Steida process
- Remains separate ossicle in 7-14% of patients, often bilaterally
Risk Factors
- Sports
- Ballet Dancers
- Soccer
- Downhill running
Differential Diagnosis
- Fractures & Dislocations
- Distal Tibia Fracture
- Distal Fibular Fracture
- Talus Fracture
- Calcaneus Fracture
- Subtalar Dislocation
- Ankle Fracture (& Dislocation)
- Peroneal Subluxation
- Muscle and Tendon Injuries
- Peroneal Tendon Injuries
- Achilles Tendonitis
- Achilles Tendon Rupture
- Posterior Tibial Tendon Dysfunction
- Flexor Hallucis Longus Tendinopathy
- Ligament Injuries
- Lateral Ankle Sprain
- Medial Ankle Sprain
- Syndesmotic Sprain
- Chronic Ankle Instability
- Intersection Syndrome Foot
- Bursopathies
- Retrocalcaneal Bursitis
- Nerve Injuries
- Peroneal Nerve Injury
- Tarsal Tunnel Syndrome
- Arthropathies
- Osteoarthritis of the Ankle
- Osteochondral Defect Talus
- Pediatrics
- Fifth Metatarsal Apophysitis (Iselin’s Disease)
- Calcaneal Apophysitis (Sever’s Disease)
- Other
- Haglund’s Deformity
- Posterior Ankle Impingement Syndrome
- Sinus Tarsi Syndrome
Diagnosis
- History
- Typically chronic or recurrent posterior ankle pain
- Exacerbated by push-off activities, forced plantar flexion
- Offending activities include dancing, kicking, downhill running, sliding, high heels
- History can be traumatic (acute or chronic), or overuse
- Pain is described as consistent, sharp, dull, and radiating
- Patients have a hard time pinpointing the exact location of pain
- Physical Exam: Physical Exam Ankle
- Inspect for Pes Planus, Pes Cavus
- Pain or tenderness deep to the Achilles tendon
- Pain is worse with plantar flexion
- Special Tests
- Plantar Flexion Test: Hindfoot pain aggravated by plantar flexion of the ankle
Radiographs
- Standard Radiographs Ankle
- Lateral view is most helpful observe osseous lesions of hindfoot
- Posterior impingement (PIM) view
- Recommended instead of a conventional lateral view for symptomatic hindfoot pain
- lateral, 25-degree external rotation, oblique view of the ankle
- Significant superior diagnostic accuracy compared with the lateral view in the detection of os trigonum[6]
- Potential findings
- May show acute or chronic fracture of Trigonal Process
- Presence of Os Trigonum
- Impingement on a dynamic view
- Posterior ankle calcified tissue
CT
- Can be useful to clarify osseous dysfunction
- Provides fine detail regarding the size, location, and number of anatomical bony abnormalities
- May not differentiate between old fracture and os trigonous
Bone Scintigraphy
- Can help clarify the acuity of fracture of the trigonal process
MRI
- Imaging study of choice in patients with PAIS[9]
- Potential findings
- Bone contusion
- Pseudarthrosis
- Fragmentation
- FHL Tenosynovitis
- Identify anomalous muscles
- Can exclude other causes of posterior ankle pain
Diagnostic Injection
- Can be performed with local anesthetic to confirm the suspected diagnosis
- Generally under ultrasound guidance
Treatment
Nonoperative
- General
- Approach is generally driven by etiology
- Maquirriain proposed a treatment algorithm
- Indications
- Trigonal process disease
- FHL tenosynovitis
- Relative rest and activity modification
- PAIS often improves with rest alone
- Avoidance of forced plantar flexion
- Ice Therapy
- NSAIDS
- Immobilization
- Occasionally, casting for 4 to 6 weeks for trigonal process disease
- Physical Therapy
- Progressive resistive exercises and strengthening
- Orthotics
- For FHL tenosynovitis, consider strapping of the foot, and longitudinal arch supports placed in firm-sole shoes
- Corticosteroid Injection
- Can be performed for FHL tenosynovitis
Operative
- Indications
- Failure of non-surgical approach after 3 months
- Prominent calcaneus posterior process
- Severe stenosis of the fibro-osseous tunnel
- Posterior osteochondral ankle lesions
- Technique
- surgical excision of the fractured trigonal process or os trigonum
- Resection of prominent calcaneus posterior process
