Ankle Pain and……the Neck! (Part 1)
A couple of weeks ago a patient was referred to me with sinus tarsi syndrome. The sinus tarsi is a small boney canal under the talus, the bone below your two shin bones. Sinus tarsi syndrome is considered by some to be an inaccurate diagnosis in that it can be further refined (Frey et al 1999). For example the term ‘sinus tarsi syndrome’ is diagnosed on the basis of pain in the sinus tarsi. This can be further diagnosed by checking pain during movement or whether injection of an aesthetic to the sinus tarsi eliminates the symptoms. However the diagnosis essentially means ‘pain there’. It doesn’t explain the condition the patient is experiencing much better. It’s analogous to a diagnosis of crepitus I once saw. A patient came in with cracking in their knees, the physiotherapist conducted their assessment and then described to the patient that they had ‘crepitus’ in their knee which essentially means cracking in the knees. In the physiotherapists defence they then gave the patient some excellent advice.
In the case of sinus tarsi syndrome the condition can be more accurately diagnosed normally as either;
- interosseous talocalcaneal ligament tears
- subtalar instability
- osteochondral injuries of the subtalar joint
- arthrofibrosis of the subtalar joint
- degenerative disease of the subtalar joint
- fibrous tarsal coalition
- chronic inflammatory changes in the sinus tarsi connective tissue
In this case it sounded like his MRI had shown degenerative changes in the subtalar (below the talus) joint, specifically the region known as the sinus tarsi. (I am still awaiting his MRI, so this is still to be confirmed). Although in some cases the specifics of the diagnosis do not alter the management in most cases it should.
Degenerative conditions can often be better understood when viewing them in terms of cumulative micro-trauma. Over time small amounts of aberrant loading cause small amounts of trauma which over time wear out a tissue. In this case the sinus tarsi region of the subtalar joint is often overused due to excessive pronation (foot flattening out). This results in ‘overuse’ of the subtalar joint and more wear and tear than the body can repair, thus degeneration occurs. As the patient was a triathlete he was putting a very significant repetitive load through his sinus tarsi.
The question is then, why is their excessive pronation? Is it an orthotic deficiency? (I mean this only tongue and cheek, orthotics can be excellent for improving pronation when properly prescribed!). This patient had been to a foot doctor office multiple times to see an excellent podiatrist who had assessed his foot mechanics and found excessive pronation in the left foot and also a longer left leg. The foot doctor had provided an orthotic and some excellent advice regarding PRICE and a graded return to marathon training.
When completing my assessment I found that indeed there was an increased pronation in the left foot and also a longer leg when he lay on his back. However when he sat up the left leg was then shorter than the right. This occurred because he had an anteriorly rotated pelvis on his left side which creates a functionally longer left leg. When he sits up the pelvis rotates more posteriorly on the left side relative to the right thus the right leg then appears longer when he is sat up. In standing this anteriorly rotated pelvis creates pronation of the left foot. Try it now, stand up, ACTUALLY DO THIS!, now tip your pelvis forward, so the distance between your ribs and belly button increases, watch what happens to your feet and feel it. You’ll find your feet will flatten out as you tip the pelvis forward and as you return to normal the feet will regain their arch.
In part 2 I will discuss why he had an anteriorly rotated left pelvis and why getting his neck adjusted may be needed.
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Frey C, Feder KS, DiGiovanni C. Arthroscopic evaluation of the subtalar joint: does sinus tarsi syndrome exist?. Foot Ankle Int. 1999 20(3):185-191