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Posterior Ankle Impingement Syndrome
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Contents
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
Background
- This page refers to Posterior Ankle Impingement Syndrome (PAIS)
History
Epidemiology
- True incidence is unknown
- Reported to be 18% in all ankle impingement-type problems in runners[1]
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"[2] or "bony impingement"[3] 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
Etiology
Osseous Lesions
- Stieda 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 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 central axis
- Os Trigonum
Risk Factors
- Sports[5]
- Ballet Dancers
- Soccer
- Downhill running
Differential Diagnosis
- Fractures & Dislocations
- Muscle and Tendon Injuries
- Ligament Injuries
- Bursopathies
- Nerve Injuries
- Arthropathies
- Pediatrics
- Fifth Metatarsal Apophysitis (Iselin's Disease)
- Calcaneal Apophysitis (Sever's Disease)
- Triplane Fracture
- Other
Clinical Features
- 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
Evaluation
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 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[7]
- May not differentiate between old fracture and os trignoum
Bone Scintigraphy
- Can help clarify acuity of fracture of the trigonal process
MRI

Ultrasound guided diagnostic injection of the FHL tendon[8]
- 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
Classification
- Generally classified based on etiology
Management

Proposed treatment algorithm from Maquirriain[10]
Nonoperative
- General
- Approach is generally driven by etiology
- Maquirriain proposed a treatment algorithm[10]
- Indications
- Trigonal process disease
- FHL tenosynovitis
- Relative rest and activity modification
- PAIS often improves with rest alone[11]
- 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
Rehab and Return to Play
Rehabilitation
- Needs to be updated
Return to Play/ Work
- Consider protective dorsiflexion taping
Complications and Prognosis
Prognosis
- Nonsurgical
- Treatment reportedly has been successful in approximately 60% of patients[12]
- Need for surgery
- Approximately 40% patients eventually require surgical intervention due to intractable hindfoot pain (need citation)
- Surgical outcomes
Complications
- Compensatory injuries
- Lateral Ankle Sprain
- Calf Strain
- Plantar Foot Pain
- Toe curling
See Also
- Internal
- External
- Sports Medicine Review Ankle Pain: https://www.sportsmedreview.com/by-joint/ankle/
References
- ↑ McBryde A: Disorders of the ankle and foot, in Brana WA, Kalenak A (eds): Clinical Sports Medicine. Philadelphia, PA: WB Saunders, 1991, pp 466-489.
- ↑ Jaivin, Jonathan S., and Richard D. Ferkel. "Arthroscopy of the foot and ankle." Clinics in sports medicine 13.4 (1994): 761-783.
- ↑ Hamilton, William G., Mark J. Geppert, and Francesca M. Thompson. "Pain in the posterior aspect of the ankle in dancers. Differential diagnosis and operative treatment." JBJS 78.10 (1996): 1491-1500.
- ↑ Lawson, J. P. "Symptomatic radiographic variants in extremities." Radiology 157.3 (1985): 625-631.
- ↑ Smyth NA, Zwiers R, Wiegerinck JI, Hannon CP, Murawski CD, van Dijk CN, Kennedy JG. Posterior hindfoot arthroscopy: a review. Am J Sports Med. 2014;42:225–234.
- ↑ Wiegnerinck JI, Kerkhoffs GMM, Struijs PAA, van Dijk CN. The posterior impingement-view: An alternative conventional projection to detect bony posterior ankle impingement. Arthroscopy. 2014;30:1311–1316
- ↑ Burghardt AJ, Link TM, Majumdar S. High-resolution computed tomography for clinical imaging of bone microarchitecture. Clin Orthop Relat Res. 2011;469:2179–2193.
- ↑ 8.0 8.1 Yasui Y, Hannon CP, Hurley E, Kennedy JG. Posterior ankle impingement syndrome: A systematic four-stage approach. World J Orthop. 2016;7(10):657-663.
- ↑ Wakeley, C. J., D. P. Johnson, and I. Watt. "The value of MR imaging in the diagnosis of the os trigonum syndrome." Skeletal radiology 25.2 (1996): 133-136.
- ↑ 10.0 10.1 Maquirriain, Javier. "Posterior ankle impingement syndrome." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 13.6 (2005): 365-371.
- ↑ Frey C: Injuries to the subtalar joint, in Pfeffer GB (ed): Chronic Ankle Pain in the Athlete. Rosemont, IL: American Academy of Orthopaedic Surgeons, 2000, pp 21-42.
- ↑ Hedrick MR, McBryde AM: Posterior ankle impingement. Foot Ankle 1994; 15:2-8.
- ↑ Zwiers R, Wiegerinck JI, Murawski CD, Smyth NA, Kennedy JG, van Dijk CN. Surgical treatment for posterior ankle impingement. Arthroscopy. 2013;29:1263–1270.