Review of the Sinus Tarsi Syndrome
The sinus tarsi is a poorly understood area and a common source of lateral hindfoot pain. The sinus tarsi’s bony borders include the neck of the talus and the most anterior superior portion of the calcaneus (1). Within the sinus tarsi there are five ligaments and a section of adipose tissue (1). The primary ligament structures include the cervical ligament (CL), the interosseous talocalcaneal ligament (ITCL), and the extensor retinaculum. The sinus tarsi is considered a region of the subtalar joint (2). The primary role of the sinus tarsi is stabilize the hindfoot in inversion and eversion (1). Etiologies of pain within the sinus tarsi region are not well understood, but typically occur after trauma that leads to tearing of the CL and ITCL. After tearing of the intrinsic ligaments of the subtalar joint, which include the CL and ITCL, the subtalar joint will have excess inversion and eversion (5). The excess motion leads to subtalar joint fibrosis and synovitis (5).
Providers typically consider sinus tarsi syndrome as a source of pain when there is lateral hindfoot pain to palpation in the area of the sinus tarsi (3). After ankle trauma, a patient can tear the ITCL, which may lead hindfoot instability (4). On physical exam, reproduction of excessive medial shift of the calcaneus can also aid in diagnosis of sinus tarsi syndrome (5).
Diagnosis is difficult, as plain film radiographs cannot make the diagnosis alone. MRI can help aid in making the diagnosis. MRI findings that are consistent with sinus tarsi syndrome are tearing of the interosseous talocalcaneal ligament, cervical ligament, synovial thickening, and sinus tarsi fat signal change (3). However, MRI misses a portion of interosseous talocalcaneal ligament tears and an arthroscopy may be more accurate in making the diagnosis (3). Fibrosis of the sinus tarsi fat on MRI can also be a sign of previous damage to the sinus tarsi ligaments (3)
Treatment of the sinus tarsi syndrome typically involves conservative treatments first line. Conservative treatments include a period of immobilization, followed by physical therapy (4). If pain remains persistent, a corticosteroid injection can be done within the sinus tarsi (4). Foot orthoses with a medial heel wedge or arch support can also be used to help stabilize the subtalar joint (5, 7). Arthroscopic surgery can be considered in those patients who fail conservative treatment (4).
Sinus tarsi syndrome is a vague and sometimes confusing term that typically involves lateral hindfoot pain and the feeling of ankle instability. Pain within the lateral hindfoot is suggestive of sinus tarsi syndrome and the diagnosis can be aided by an MRI. Conservative treatments are first line and arthroscopy surgery can be considered for persistent pain.
By: Gregory Rubin, DO
1) Arshad, Zaki, and Maneesh Bhatia. “Current Concepts in Sinus Tarsi Syndrome: A Scoping Review.” Foot and Ankle Surgery: Official Journal of the European Society of Foot and Ankle Surgeons, vol. 27, no. 6, Aug. 2021, pp. 615–21. PubMed, https://doi.org/10.1016/j.fas.2020.08.013.
2) Frey, C., et al. “Arthroscopic Evaluation of the Subtalar Joint: Does Sinus Tarsi Syndrome Exist?” Foot & Ankle International, vol. 20, no. 3, Mar. 1999, pp. 185–91. PubMed, https://doi.org/10.1177/107110079902000309.
3) Lee, Keun-Bae, et al. “Efficacy of MRI versus Arthroscopy for Evaluation of Sinus Tarsi Syndrome.” Foot & Ankle International, vol. 29, no. 11, Nov. 2008, pp. 1111–16. PubMed, https://doi.org/10.3113/FAI.2008.1111.
4) Lauf, Kenny, et al. “Six out of Ten Patients with Sinus Tarsi Syndrome Returned to Pre-Injury Type of Sport after Subtalar Arthroscopy.” Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA, vol. 29, no. 8, Aug. 2021, pp. 2485–94. PubMed, https://doi.org/10.1007/s00167-020-06385-8.
5) Helgeson, Kevin. “Examination and Intervention for Sinus Tarsi Syndrome.” North American Journal of Sports Physical Therapy: NAJSPT, vol. 4, no. 1, Feb. 2009, pp. 29–37.
6) Helms, Clyde. “Magnetic Resonance Imaging of the Foot and Ankle.” Fundamentals of Skeletal Radiology.
7) Taylor, Michael. “Impingement Syndromes of the Ankle.” Baxter’s The Foot And Ankle in Sport.