Posterior Tibial Tendon Dislocation

The tibialis posterior tendon originates from the interosseous membrane and posterior portion of the tibia and fibula and inserts on multiple locations including the navicular,  cuneiform, cuboid, and second, third, and fourth metatarsal base (1). On its course distal, the posterior tibialis tendon will be the most superficial structure at the level of the posterior medial malleolus (3). The tendon will travel through a fibro-osseous tunnel that lies deep to the flexor retinaculum (3). During an ankle injury, the tunnel and flexor retinaculum can become torn, allowing the tendon to travel anteriorly (3). These injuries are categorized as either a type 1 injury, which is a dislocation due to anterior retinaculum flexor rupture, or type 2, which involves subperiosteal dislocation with tibialis posterior flap (3).

Image on the left is normal tendon anatomy, middle image is subcutaneous dislocation, and image on the right shows subperiosteal dislocation (6) 

Traumatic dislocation of the tibialis posterior tendon is not commonly seen and can be difficult to diagnose. It is more commonly seen in younger adults (7). Patients will typically complain of an injury where they had an inverted foot that was plantarflexed or dorsiflexed and then experienced a strong posterior tibial tendon contraction (4). It is not uncommon for the patient to have felt a “pop” in the ankle or to experience recurrent “snapping” after the injury (5). The diagnosis may be missed initially and patients will present with prolonged medial ankle pain after ankle injury (4). Having a shallow retromalleolar groove is a risk factor for tendon dislocation (5).

Physical examination of the ankle will sometimes show a palpable tendon overlying the anterior portion of the tibia (3). There may also be medial ankle edema and ecchymosis (7). Standard radiographs are typically normal (4). However, dynamic ultrasound can also be done to try and provoke the tendon dislocation (3). The tendon will dislocate anteriorly from the retromalleolar groove of the medial malleolus (6).

Ultrasound image shows the asterisk where the tibia posterior tendon should be in the groove (6)

MRI will also assist in diagnosis of a posterior tibia tendon dislocation (7). The MRI may show a tear of the flexor retinaculum and can also assess whether the tendon is located in the retromalleolar groove (7).

A medial and anterior dislocated posterior tibia tendon on MRI (7)

Surgery is typically the mainstay treatment for a tibialis posterior tendon dislocation (3). This could involve repair of the retinaculum and possible groove deepening (3). There is not significant data regarding the non-operative care for these injuries (5).

Dislocations of the posterior tibial tendon are not commonly seen and frequently misdiagnosed. Ultrasound and MRI can assist providers in a successful diagnosis. Non-operative treatment typically fails and surgery is done in most cases.

By Gregory Rubin, DO
rubinsportsmed.com

– More Ankle Pain @ Sports Med Reviewhttps://www.sportsmedreview.com/by-joint/ankle/

– More Posterior Tibial Tendon Dislocation @ Wiki Sports Medicine: https://wikism.org/Posterior_Tibial_Tendon_Dislocation

References

1)      Hansen, John T.,, et al. Netter’s Clinical Anatomy. 4th edition. Philadelphia, PA, Elsevier, 2019

2)      Matsui, Tomohiro, et al. “Recurrent Dislocation of the Tibialis Posterior Tendon Treated With Suture Tape: A Case Report of an Innovative Operative Procedure.” The Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons, vol. 57, no. 6, 2018, pp. 1267–71. PubMed, https://doi.org/10.1053/j.jfas.2018.03.046.

3)      Al Khudairy, A., et al. “The Unexpected With Ankle Fracture: Traumatic Tibialis Posterior Tendon Dislocation: A Case Report and Literature Review.” Foot & Ankle Specialist, vol. 6, no. 6, Dec. 2013, pp. 482–89. DOI.org (Crossref), https://doi.org/10.1177/1938640013502726.

4)      Goucher, Nicholas R., et al. “Dislocation of the Posterior Tibial Tendon: A Literature Review and Presentation of Two Cases.” The Iowa Orthopaedic Journal, vol. 26, 2006, pp. 122–26. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1888604/.

5)      Lohrer H, Nauck T. Posterior tibial tendon dislocation: a systematic review of the literature and presentation of a caseBritish Journal of Sports Medicine 2010;44:398-406.

6)      Prato, Nicoló, et al. “Sonography of Posterior Tibialis Tendon Dislocation.” Journal of Ultrasound in Medicine, vol. 23, no. 5, May 2004, pp. 701–05. DOI.org (Crossref), https://doi.org/10.7863/jum.2004.23.5.701.

 

7)      Bencardino, J., et al. “MR Imaging of Dislocation of the Posterior Tibial Tendon.” American Journal of Roentgenology, vol. 169, no. 4, Oct. 1997, pp. 1109–12. DOI.org (Crossref), https://doi.org/10.2214/ajr.169.4.9308473.