Sinus tarsi syndrome

Last evidence check March 2011


The sinus tarsi is an anatomical space bounded by the talus and calcaneum, the talocalcaneonavicular joint anteriorly and posterior facet of the subtalar joint posteriorly. It is medially continuous with the much narrower tarsal canal. The sinus tarsi contains the cervical ligament and the three roots of the inferior extensor retinaculum. The tarsal canal contains the interosseous talocalcaneal ligament and the deep and intermediate roots of the inferior extensor retinaculum. Both the sinus and the canal contain blood vessels - which are important for the nutrition of the talus - and nerves. The extensor digitorum brevis and bifurcate ligament lie anterior to the sinus tarsi.

The term "sinus tarsi syndrome" was first applied in O’Connor in 1958 to a syndrome of post-traumatic lateral hindfoot pain and instability which was relieved by the injection of local anaesthetic into the sinus tarsi. The same diagnostic criteria seem to have been applied reasonably consistently throughout the literature. The incidence of sinus tarsi syndrome following ankle injury has not been published, but it is not very common. Some authors use the term "sinus tarsi syndrome" to refer to lateral hindfoot pain associated with inflammatory conditions or hindfoot valgus, but we prefer to refer to this as "lateral subtalar impingement".


Pathological examination of tissue removed from patients with sinus tarsi syndrome include chronic inflammatory changes, fat necrosis, fibrosis and synovial cysts.

The cause of pain has been postulated to be vascular engorgement or nerve irritation, both due to fibrosis.

A recent paper by Frey et al suggests (on the basis of arthroscopic examination) that sinus tarsi syndrome is an inaccurate diagnosis which can always be refined by adequate investigation, particularly by subtalar arthroscopy. The following are the commonest underlying abnormalities found in this and other papers:

Clinical assessment

Patients complain of pain in the sinus tarsi region. There is usually a history of ankle injury.

Clinical examination reveals tenderness over the sinus tarsi which is relieved by local anaesthetic injection. Pain may be exacerbated by varus tilting of the heel (unlike the pain of lateral impingement which is worse on valgus tilting of the heel) or walking on uneven ground. A feeling of subtalar opening may be felt on the varus tilt test. Abnormalities in the ankle are common: up to 50% have ankle instability and/or anterolateral synovitis.


Plain radiographs are generally normal, although degenerative arthritis of the subtalar joint may be seen. Stress views of the subtalar joint (lateral or Broden views) may show instability, but this is difficult to demonstrate and the diagnostic criteria are not clear. Subtalar arthrography may show obliteration of the anterior micro-recess but sensitivity is not very high.

MR shows inflammatory and fibrotic changes well. The interosseous talocalcaneal ligament may be shown to be torn but some observers find that non-specific changes make this difficult to visualise. MR also shows damage to the subtalar joint and surrounding structures. Lee (2008) assessed the diagnositic accuracy of MRI using subtalar arthroscopy as the reference standard. MRI had sensitivity of 44% and specificity of 60% for interosseous talocalcaneal ligament tears, 73% and 89% for cervical ligament tears, 71% and 92% for sinus tarsi fat alterations and 86% and 87% for synovial thickening. Complete agreement between MRI and arthroscopy was present in only 10% of patients

Taillard et al described various abnormalities on EMG examination of the peronei in patients with sinus tarsi syndrome compared with normal controls, including:

The abnormalities disappeared after local anaesthetic injection of the sinus tarsi or successful surgery.


Non-surgical management should include:

Two surgical techniques for sinus tarsi syndrome are described in the literature.

Open debridement

Excision of the entire contents of the sinus tarsi, including in some cases the interosseous talocalcaneal ligament was the treatment recommended by O'Connor in the original description of the condition. Results of this are reported very favourably, with most or all patients relieved of pain. Taillard et al summarise results from the literature as showing 88 cases treated surgically (including their own). There were 66 excellent, 16 good and six poor results. Half of these were in O'Connor's original paper and none of the papers describe outcome criteria in any detail.


Arthroscopic examination and debridement of the posterior subtalar joint and sinus tarsi allows diagnosis and treatment with low morbidity. 94% of 49 patients treated by Frey (1999) were improved at 1-7.75 years’ follow-up although half had some residual symptoms. Fey found that 36/49 atients had interosseous talocalcaneal ligament tears, 27 had soft tissue impingement lesions, 7 arthrofibrosis, 4 subtalar OA and 2 talocalcaneal coalitions. This paper leaves open some questions about patient selection and evaluation.

Lee (2008) reported 33 subtalar arthroscopies for sinus tarsi syndrome. 29 patients had ligament tears, 18 synovitis, 8 arthrofibrosis of the posterior subtalar joint and 7 soft tissue impingement. Mean VAS pain score improved from 7.3-2.7/10 and mean AOFAS score from 43-86/100, although several patients still had some pain.

In addition, surgical treatment may be indicated for concomitant ankle synovitis or instability, subtalar instability or foot deformity.