Part 2: Bone related shin splints: A right pain in the……SHIN!

Medial tibial stress syndrome pretty much covers most of the bony component of shin splints. It commonly affects the lower two thirds of the inside border of the tibia. The stress to the bone initially causes periostitis at first, which is inflammation in the lining of the bone. An escalation of this takes it to oedema of the bone marrow inside the bone. The bone gradually weakens and the final stage is a stress fracture.

Incidence:

Medial tibial stress syndrome in runners has an incidence ranging from 13.6% to 20.0% (Lopes  et al 2012) but other sports such as dancing and football can also get Shin splints. Interestingly stress fracture risk is between 1.5 to 3.5 times more in women than in men (Dugan & Weber 2007). This is thought to be related to bone density being lower in females.

How long does it take to resolve?

Overall medial tibial stress syndrome took 72 days on average to recovery in novice runners according to Nielsen et al (2014). More specifically Periostitis will recover quickly (2-4 weeks) as the injury is still minor, however if you continue to overload the bone then you move onto bone marrow oedema, which takes a little longer, 3-6 weeks on average.

Now if you have a medial tibial stress fracture then it can heal relatively quickly as it has a great blood supply. This means on average it normally takes 4-8 weeks for the pain to resolve so you could be back to full sport within 8-12 weeks if you progressively build back up.

The bad news:

It is possible to get an anterior tibial stress fracture but this is much less common, which is just as well, as the bone here, has poor blood supply so the healing time can be between 4- 6 months!

Diagnosis:

Now everyone is thinking X-ray, right?

Strangely X-rays are inaccurate in diagnosing a stress fracture until after 4 weeks!

An MRI is the most sensitive radiological examination for bone related shin splints. It has been found to be 88% sensitive and 100% specific, which means it is very accurate (Gaeta et al 2005).

Obviously an MRI is hard to come by so a quick way to get a good idea of bone related shin splints is to palpate the area. Typically periostitis and bone marrow oedema tend to be painful and tender over a wider area, whereas stress fracture is more localised to a smaller area.

Another test commonly used is the single leg hop test, which is likely to cause pain if you have a stress fracture.

Interestingly Romani et al (2000) found that pain brought on with 1 MHz continuous ultrasound isn't sensitive enough for identifying tibial stress fractures. Which is a shame as this would be very useful due to the low cost and ease of access of ultrasound compared to MRI’s.

Symptoms:

Generally pain is located on the inside lower two thirds of the tibia bone for a Medial tibial stress syndrome. Pain is usually a bit more spread out for Periostitis and Bone Marrow oedema and more localised for stress fracture. For an anterior tibial stress fracture the pain is more on the front of the shin but remember this is not as common.

Causes:

This is the complicated part because everyone is different, with different risk factors, so not all of these things below will be right for everyone but they are the most common.

Poor training methods:

Doing too much – High mileage (20 miles or more a week) has been found to be a risk factor (Korpelainen et al 2001), which was also supported by Wilder & Sethi (2004).

Not doing enough then doing too much – Under loading of the structure causes weakness of the tissues, which exposes the structure making it easier to overload.

Poor fitness:

Jones et al (2002) found that lower aerobic fitness is a risk factor for stress fracture in the lower limb. This is likely due to fatigue affecting technique and form.

Not having enough recovery between sessions:

Ristolainen (2014) found that athletes with less than 2 rest days per week have a 5.2 times higher risk of injury!

Incorrect training surfaces:

Hard surfaces obviously don’t shock absorb well and cambered and uneven surfaces too, can be an issue, as this will alter the stress to the body (Dugan & Weber 2007).

Muscle dysfunction/inflexibility:

Tibialis Anterior, which attaches to the front of the tibia and in some cases the Soleus physically pull onto their attachment to the bone and this causes the periosteum to become inflamed. So if these muscles are overused or inflexible then this will increase the risk.

Also Tibialis Posterior is commonly at fault in people who have poor pronation control. This then transmits the force onto the bone itself (Beck 1998).

Athletes with calf muscle weakness and poor endurance are more likely to fatigue, which leads to altered running mechanics, and strain on the tibia (Beck 1998).

Niemuth et al (2005), found that poor core and hip strength/control contributed to overuse injury in the lower limb, in particular the Gluteus medius muscle causes knock on effects such as internal rotation and pronation forces, which could lead to shin splints.

Shoe design:

Barefoot & minimal footwear had significantly greater eversion & tibial internal rotation in running, which causes more strain to the tissues that attach to the bone (Sinclair et al 2013).

Shock absorption can be an issue especially for the over supinator and Thacker et al (2002) found that good shock absorbing trainers helps to reduce the risk.

Biomechanics:

A high longitudinal arch and an excessive forefoot varus, which are associated with excessive supination can cause impaired shock absorption, which increases force ‘spikes’ that damages tissues directly (Korpelainen et al 2001).

Running with a rear foot strike has significantly higher rates of repetitive stress injury than a forefoot strike (Daoud et al 2012). This being said, Glauberman  and Cavanagh (2014) found the opposite: Forefoot striking had higher loads in the tibia compared to rearfoot striking. Remember everyone is different!

Korpelainen et al (2001) found that leg length inequality potentially causes an increased risk factor.

Weight:

If you are heavier, then this too can increase the risk of shin splints (Hamstra-Wright et al 2014).

Treatments:

Here is a list of common advice and treatment:

In the first 72 hours of symptoms or in the first 72 hours after irritating the injury use P.O.L.I.C.E:

PROTECT from aggravating activities such as running but this will be anything that causes pain to increase during, after or the next day.

OPTIMAL LOADING: Don’t completely rest though. It may be possible to train in other ways for example elliptical training uses less medial hamstring, gastrocnemius, soleus & tibialis anterior muscles compared to walking (Burnfield et al 2010). Obviously swimming and cycling should be okay too due to the lower forces and loads.

ICE: Apply ice in a damp tea towel over the area for 20 minutes and you can re-apply every 2 hours.

COMPRESSION: use something to compress the area, such as tubigrip but make sure it is not too tight.

ELEVATE: In between activity elevate the leg.

You can train the other leg:

Strength training the non-fractured limb improved strength & movement in the fractured limb (Magnus et al 2013).

Acupuncture:

Acupuncture may be beneficial in the early treatment of persistent fracture pain (Edmondson 2013). Basically this would only work for pain but if you aren’t continuing to overload the injury then you shouldn’t technically be in pain so this treatment would be unnecessary.

Non Steroidal Anti-inflammatories (NSAID's):

NSAID's can help to settle the acute inflammation.

After things have settled down then the following can help:

Orthotics:

Semi rigid orthoses reduced shin splints in military conscripts (Larsen et al 2002).

Custom-made biomechanical insoles may be more effective than no insoles for reducing shin splints (Yeung et al 2011).

The use of shock absorbing insoles reduces stress fractures in athletes & the military (Gillespie & Grant (2000).

Ultrasound:

Ultrasound works best for: Ligament, Tendon, Fascia, Joint capsules & Scar tissue as they absorb it the most (Sparrow et al 2005). Basically the denser the soft tissue the better, which generally doesn’t include bone. However Busse et al (2002) found that low intensity pulsed ultrasound reduced fracture healing time and the mean difference in healing time was 64 days when compared to the control group.

Strengthening the weak muscles:

Now just because a muscle is ‘strong’ on a resisted test, doesn’t mean that it works well in function. This can make it difficult to fully evaluate what to target. If the muscle is weak on a resisted test then it is likely to be weak in function, in this case, you should target the muscle. However, if it is the other way around, then you need to look at how they move and then try to understand if the abnormal motion is caused by weakness or something else. This being said, Niemuth et al (2005) found it beneficial to strengthen around the hip. They looked at hip abductors mostly but found adductor and flexor strengthening was also helpful.

Stretching the tight muscles:

Obviously this will differ in each person so you need to see what structures are tight and stretch them. Common areas tend to be the calf and the hamstrings (Wilder & Sethi 2004).

Gait/ Running re-training:

Gait analysis can be important because it can highlight any technique issues and see abnormal movements. This can then be targeted by gait and running training and drill work to rectify the issues and lower the risks (Beck 1998).

Footwear:

You should change running shoes every 250–500 miles, because trainers can lose up to 40% of their shock absorption and support after this point (Cook et al 1985).

So hopefully this gives you a little insight into the bone related part of shin splints. Remember that everyone is different so you should get assessed for your individual problem otherwise you could be barking up the wrong tree.

Stay tuned for the next installment of the shin splints blog series coming soon.

If you need any further information or would like to book an appointment then call Hawkes Physiotherapy on 01782 771861 or 07866195914

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