Abstract
Ankle sprains are very common, and usually tear or partly tear one or more of the ligaments on the outer side of the ankle. The ankle joint is only designed to move up and down, whereas there is another joint immediately below the ankle joint, called the subtalar joint, which is designed to do the tilting in and out movement. If the foot tilts over too far, the subtalar joint reaches the end of its movement and then the ankle ligaments stretch and tear.
It is possible that variations of subtalar range of movement may contribute to ankle sprains or symptoms of weakness or instability. In particular, if the subtalar joint is unusually restricted in its movement, then the foot does not have to tilt far before the lateral ligaments tear.
If on the other hand the subtalar joint is particularly mobile and has excessive movement, then the foot may go right over without actually tearing ligaments and feel insecure or unstable simply as a result of abnormal excessive movement.
Recent studies have demonstrated what we have always suspected, that clinical examination and assessment of subtalar range of movement is highly unreliable. In order to accurately assess whether your subtalar range of movement is unusually restricted or excessive, the only standard and accurate method to date has been to obtain a CT scan.
We are now undertaking a study to establish whether plain xrays with a small metal clamp applied to the heel might not be a simpler, cheaper, quicker and equally reliable method of assessment of subtalar movement.
If you would like to know if your subtalar movement might be a contributing factor to either stiffness or insecurity of your ankle, we invite you to be examined clinically, by plain xrays at SPORTSMED•SA, and by a CT scan at Jones & Partners Radiology at Burnside. The xray and CT investigations would be bulk billed under Medicare so that you would not incur any personal cost and the information could well be helpful in assessing your ankle problem, or at least be reassuring that the subtalar joint has a normal range of movement.
The investigations can be arranged through your treating doctor, physiotherapist or podiatrist or by contacting Dr Roger Paterson, Foot and Ankle Surgeon, or Mr Stephen Landers, his Research Assistant, on Ph: 8362 7788.
The CT scan would be a very limited investigation resulting in minimum radiation exposure, comparable to the normal xrays. Further information on what is involved in having a CT scan is attached.
Neither the CT scan nor the plain xrays should cause any more than minor discomfort as the foot is tilted through its full range of movement, or from the padded pressure of the G clamp.
SPORTSMED•SA remains committed to excellence in treating active people of all ages, and through these investigations, we plan to further enhance the quality of assessment and care of people who suffer ankle problems.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
