Family doctor

Introduction

I think I've got shin splints - how can I get rid of them quickly?

How often do I hear this opening line from a patient? Very often! What are shin splints? That's the worry - shin splints is not a diagnosis. Its a catch-all "basket" phrase which is indiscriminatelyused to describe anything and everything that's sore between the knee and the ankle!

It will most likely be a muscle/tendon overuse problem, a muscle compartment problem, or a stress fracture, or a combination of all three.

Why has it occurred?

This will have a lot to do with the sport involved, the patient's lower limb and foot mechanics, their muscle balance (or more aptly imbalances), often the type of footwear used relative to the foot type, and the individual's training programme leading up to an event.

All too often the hurry to build up training, especially the "miles under the belt", will result in the "too much too soon" phenomenon with breakdown of components of the musculoskeletal system that can't accommodate change in mileage, intensity, and duration of activity as quickly as most mere mortals would like them too!

Most of us will only tolerate about a 10% increase in weekly training time, load, run duration, and frequency of training a week without risking injury.

Why do some sports seem to cause more shin pain than others?

Obviously the nature of a sport means that certain bones and muscles have the potential for stress from overuse and in this case sports involving repetitive and high impact lower limb activity like running, and jumping, will show a high incidence of shin problems.

Poor foot mechanics are found in a lot of sports people and this means that some athletes will develop shin problems after only modest amounts of activity. Others seem to last huge training mileages often breaking all the rules of training rules and get away with it - these individuals will usually have been endowed with lower limbs which absorb shock better than most, are better muscle balanced and don't overpronate. This excessive foot pronation means that their ankles/feet roll in too far after landing and before toe-off. This inevitably involves stress at the muscle attachments on the shinbones, particularly along the inside border of the tibia (inside shinbone). The bone will be sore to touch over a length of 10 cm or more. This is usually called "medial tibial stress syndrome".

What is the treatment?

Treatment needs to involve seeing a good sports podiatrist who will probably analyse your gait on a treadmill while running or walking, then assess your lower limb anatomy in great detail. They may then advise you to invest in a pair of shoes that are better suited to your particular foot mechanics and will help control usually excessive pronation, or fit you out in a pair of orthotics (footwear modifications) that will do this more effectively.

You also need to have a good physio do a muscle balance assessment, as often exacerbating the bad foot mechanics is weakness in some of the key stabilising muscles starting right up at the top of the lower limb kinetic chain - the pelvis. You've all heard of gluteus maximus (the largest buttock muscle) but more important in assessment of lower limb injury patients is testing for firing and strength of gluteus medius. This muscle is hugely important in normal gait - if it is not working for you properly, you certainly won't be running as efficiently as you could be. Because it stabilises the pelvis during gait, if it is weak there's a lot more hip-sway and lateral movement - wasted energy if you're thinking about your running times!

Now if the area of tenderness is much more localised and only involves a few centimetres of bone length in the tibia, and that area is sore on impact (e.g. hopping on that leg is sore in that spot), you may well have a stress fracture in the tibia bone.

You do need to have an x-ray, mainly to exclude other diagnoses. The plain x-ray hardly ever shows up a stress fracture in the tibia bone - even later on. But very occasionally, bone tumors, infections etc. present themselves with a very similar history of onset with similar examination findings, and need to be ruled out.

If there's any doubt, then you should have a bone scan which is almost 100% sensitive for a stress fracture. It involves having an injection of radioactive dye into your vein which then travels around the bloodstream and gets taken up by active bone cells. It will show up a "hot spot" at the site of injury. This will necessitate some rest (likely 6-8 weeks) from provocative activity but you can maintain your fitness with cycling, and water running. In the case of medial tibial stress syndrome discussed above, the bone scan will show up a much more lengthy area of increased uptake along the medial tibial border.

The other shin pain presentation where a bone scan may help diagnosis is compartment syndrome where the increased tissue tension caused by tight muscle in a relatively inelastic compartment causes pain due to ischaemia - lack of blood supply. It is really akin to angina - chest pain which occurs due to poor blood supply to the heart muscle which might be due to blood vessel narrowing, or spasm compartment syndrome. This typically comes on after a certain amount of exercise and is associated with a feeling of tightness, (sometimes described as woody hardness), and occasionally pins and needles, and poor circulation in the foot if the nerves and blood vessels supplying the foot are also being compressed in the tight muscle compartments.

There are some subtle signs on a bone scan which suggest compartment syndrome but the diagnostic test is really to have the "compartment pressures" measured. This involves having needle catheters attached to a pressure monitor inserted into the particular muscle compartment before and after exercise to measure the resting pressure and exercise pressures. Abnormally high pressures indicate that surgery "may" be indicated to slit the sheath around the compartment in order to reduce the pressure within.

Getting help

Hopefully you aren't currently suffering from any of these types of shin pain - if you are, make sure you don't accept a diagnosis of "shin splints" because it isn't a diagnosis! Depending on the actual cause of your shin pain, there may be totally different treatment regimes indicated. They'll all get better if you rest the shins but that's not the answer either - as soon as you return to the same activity, it'll come back to haunt you as the causative problems will probably still be there in your foot mechanics and muscle imbalances.