What are Shin Splints?
The term ‘shin splints’ is often said as the layman’s term for Medial Tibial Stress Syndrome (MTSS) which is pain on the tibia (shin bone). However, shin splints is more of an umbrella term for pain felt on the front of the leg between the knee and the ankle.
The World Health Organisation would like us health professionals to stop using vague terminology. It is best to use terms that are related to the injured anatomy and that outline the diagnosis.
There are 3 main types of shin splints pain are:
- Medial Tibial Stress Syndrome (MTSS)
- Tibial Stress Fracture
- Chronic Exertional Compartment Syndrome (CECS)
This article will describe the above 3 shin pains. These three conditions can co-exist, so more than more type can be present at a time.
Causes and factors contributing to the development of these shin splints will be discussed. Short and long term treatment and preventative steps are also outlined.
There are other causes of pain at the front of the leg, the muscular part of the front of leg can cause pain too. These injuries and conditions will be discussed in separate article about exercise-induced leg pain.
‘Shin splints’ is an umbrella terms for many conditions that cause pain in the shin.
What’s the Anatomy Involved?
The tibia and fibula are the two lower leg bones. The tibia is the inside bone and is the larger of the two bones. It forms the knee joint with the femur and the ankle joint with the fibula and talus.
The tibia has many muscle attachments, these muscles move the knee, ankle and foot joints. Therefore, the tibia assists with movements such as walking, running, jumping, standing all while supporting body weight.
Muscles are surrounded by a thin, cling-film like coat called, fascia. Muscles are then grouped together and surrounded by more fascia. The lower leg has 4 groups or ‘compartments’. The muscles at the front of the leg form the anterior compartment. This compartment contains the tibialis posterior, flexor hallucis longus and flexor digitorum longus muscles.
The tibia bone’s outer most layer is the periosteum. This is a very thin layer that transports the bone’s blood and nutrient supply.
Medial Tibial Stress Syndrome (MTSS)
Signs and Symptoms
Also known as Medial Tibial Traction Periostitis, this condition is an overuse injury due to exercise and physical activity. Pain is felt along the front and bony side of the shin bone, above the ankle and usually occurs in the lower 2/3 of the leg. This site can be very painful to touch and may present with mild swelling.
The pain is usually present at the beginning of activity and decreases with warming up and stretching. Pain can returns gradually after exercise and is more painful the morning after activity. Chronic cases may see pain with continued exercise.
The site of pain is typically spread over a minimum of 5cm (1). MTSS can be reliability diagnosed with clinical history taking and physical examination (4).
What Causes MTSS Shin Pain?
The term syndrome does imply that the exact disease process isn’t known. Several theories exist to explain the cause of the pain.
As the secondary name implies, Medial Tibial Traction Periostitis, is a traction on the tibia bone from the muscles that attach onto the bone. The muscles that start their bony attachment on the tibia in this general region include the tibialis posterior, flexor digitorum longus and soleus. Deep fascia also attached to the same location.
When the repeated traction from these muscles/fascia reaches the bone’s limit, the outer layer of bone, the periosteum can be inflamed. Unfortunately for this theory, the cadaver studies find that the muscles don’t originate from the usual area of pain, but the deep fascia does, so perhaps the fascia acts likes a pulley for this traction.
The second theory doesn’t consider the condition to be a completely inflammatory process but rather an over stimulation of bone.
When exercising, the tibia bone has bending forces applied to it. Seeing that a wider bone can handle these forces better, the reasonably narrow tibia widens itself to cope with these forces. Widening occurs through bone cells creating more bone. If the bone cells can’t keep up the bone growth during increased physical activity and loading, micro-damage occurs. This damage causes pain and inflammation. The bending force in the tibia is at its highest in the area that MTSS is felt.
What are the Contributing Factors?
-Malalignment of the tibia, rearfoot or forefoot e.g. bowed legs
-Excessive pronation/flat feet and a low medial longitudinal arch
-Wearing worn out shoes or unsupportive shoes
-Training errors such as a rapid increase in frequency, intensity or duration of activity
-Exercising on hard, uneven ground or sloping surfaces
-Physical activity with high loading forces in the tibia region e.g. running, football, soccer, netball, basketball and dancing
– Muscle weaknesses or imbalances
-Poor flexibility
-Elevated body mass >30 BMI
-Osteoporosis
-Smoking
Having bowed legs can increase your risk of MTSS
Treatment for MTSS Shin Splints
Avoid painful activity for 7-10 days. Be careful and potentially avoid stretching and strengthening while the muscles are sore.
Gradual return to high impact activity, in the meantime, cycling and pool running are great exercises to maintain cardiovascular fitness.
See preventative actions at the end of this article for more helpful hints.
Tibial Stress Fracture
Signs and Symptoms
This type of stress fracture is a small incomplete crack in the tibia bone. This overuse bone injury is worse with high impact which doesn’t warm up with activity. Pain may be constant and felt when resting. Pain in often described as sharp and may be so painful that exercise is voluntarily stopped. There may be associated swelling.
The site of pain is more focal than MTSS, with a more localised area of tenderness of 2-3cm (2,3). It is usually more in the middle of the tibia.
A clinical diagnosis can be made through history taking and physical examination. This diagnosis is confirmed though imaging such a x-ray, bone scan, MRI or CT scan.
A diagnostic and treatment protocol for stress fractures (5).
There is more than one place on the tibia that a stress fracture can occur. One type of fracture is called an anterior tibia cortex stress fracture. This type of fracture is much less common than the typical stress fracture which occurs in the distal third of the posteromedial cortex. A fracture in the tibia cortex is at higher risk to extremely slow healing and may require surgery.
What’s Causes a Tibial Stress Fracture?
A tibial stress fracture is micro crack in the tibia caused by repeated forces. A similar cause to MTSS, in that, the bone cells can’t keep up the bone growth during increased physical activity.
Compared with MTSS, it is possible in stress fractures that there is even more bone remodelling occurring. During remodelling, the bone can be weaker than usual, making it more susceptible to injury. Tibia stress fractures can occur after MTSS if the activity level is sustained or increased.
What are the Contributing Factors?
-High-intensity training with repetitive movements such as running or jumping sports
-Inadequate rest periods
-Training errors such as a rapid increase in frequency, intensity or duration of activity
-Hard, unforgiving surfaces
-A limb length difference
-High arched, rigid foot type that is poor a shock absorbing
-Excessive pronation/flat feet
-Wearing worn out shoes or unsupportive shoes
-Poor nutrition, low vitamin D (5) and possibly calcium and protein
-Female athlete triad (eating disorders, amenorrhea, osteoporosis) (5)
-Reduced bone density in females with athletic amenorrhea
-Consuming more than 10 alcoholic drinks per week before increasing training load (5)
-Smoking (5)
Treatment
Treatment is similar to MTSS in that rest is important. A longer rest period is required, usually 4-8 weeks. Avoiding high impact and painful activities may be sufficient to rest the tibia, other cases may require a moon boot or crutches. There is some evidence that moon boots with pressure pumps may speed up the recovery of tibial stress fracture (6).
Health professionals should assess your diet, hormones and bone density for insufficiencies and abnormalities.
Some researchers have queried whether anti-inflammatory (non-steroidal) medication can delay bone healing in stress fractures (7). If pain relief tablets are required consider paracetamol instead.
A fracture in the tibia cortex is at higher risk to extremely slow healing and may require surgery.
Chronic Exertional Compartment Syndrome (CECS)
What’s Causes CECS?
As discussed above, the muscles at the front of the leg form the anterior compartment and each muscle is surrounded by fascia. During weight bearing exercise more blood and oxygen must reach the muscle. Increased blood flow increases the size of the muscles within the compartment. An increase in size increases the pressure within the compartment. If the muscle’s surrounding fascia doesn’t stretch enough for this expansion, adequate blood flow is prevented. A lack of blood means a lack of vital oxygen to the muscle. Muscles that aren’t getting enough oxygen tell you about it in the form of pain messages.
Nerves can be squished by the lack of space in and around the compartment, causing neural symptoms.
Each muscle is surrounded by fascia.
Signs and Symptoms
When exercising the pain usually takes 15-30 minutes to start and slowly increases with more exercise. The pain usually resolves with stopping activity but an ache may be felt for 15 – 30 minutes.
Due to the consistent nature of the pain, someone with extended history of CECS will know how much time, distance or intensity it takes for the pain to start.
Reported symptoms can include a deep ache with a sense of fullness and cramplike sensation. The compressed nerves can cause numbness and pins and needles. There may be associated weakness of the muscles. Just like nerves, arteries can be compressed causing a foot pulse to be absent.
A thorough history taking can indicate a CECS diagnosis. A compartment pressure test confirms the diagnosis.
Treatment for Chronic Exertional Compartment Syndrome
In the short term, rest and leg elevation. In the long term, surgery to release the compartment from its fascia.
Shin Splint Prevention
Prevention of shin splints is easier than treating it. Don’t ignore the early signs and symptoms, the recovery time for MTSS ranges significantly from 1-18 months (8). Early assessment and treatment of the early symptoms can also reduce recovery time.
Unfortunately, there aren’t any proven preventative strategies for CECS but several options exist for MTSS and stress fractures, including:
-Gradually increase training intensity and duration.
-Allow rest periods between high intensity training sessions, usually 48-72 hours.
-Wear appropriate footwear for your foot type, training surface and activity.
-Replace worn out shoes.
-Maintain leg strength, agility level, ankle flexibility and proprioception (balance) skill level required for your chosen activity.
-Perform pre exercise warm up activities such as stretching and dynamic range of motion movements.
-Consume adequate calcium in your diet.
-Shock absorbing innersole for high impact activities (6).
Replacing your worn shoes can reduce your risk of shin pain.
Podiatry and Shin Splints
Addressing underlying biomechanical factors contributing to shin splints may also be required to prevent the pain. Podiatrists perform biomechanical musculoskeletal assessments to identify contributing factors. An individualised management plan is provided and may include:
-Specific ankle stretching and strengthening exercises
-Proprioception (balance) exercises
-Training load plan
-Footwear changes
-Low impact cross training activity prescription e.g. swimming and cycling
-Pain reduction modalities such as massage, mobilisation and dry needling
-Heel raise to treat a limb length difference
-Orthotic therapy to address foot type and function
Time to get some balance in your life. It may prevent shin splints!
Get in Touch with Canberra’s Preferred Podiatrists Today
New Step Podiatry is here to assist you with the foot, ankle and leg issues that you may be experiencing. We have years of experience treating those in Belconnen, Canberra and surrounding areas, and will always put your health and comfort as our top priority.
For any questions, give us a call on 02 6198 4818 or easily book an appointment online to see the Podiatrists at our clinic.
