STRESS FRACTURES

A stress fracture results from repeated ongoing physical stress to a bone. They are usually the result of overtraining, or too much sport. Stress fractures are a common injury among sports people, especially runners. Stress fractures can occur in virtually any bone in the body but are more commonly found in the pelvis, lower leg and foot bones.

Patients usually complain of local pain and tenderness over the region and sometimes night pain. X–ray can confirm stress fractures if the stress fracture has been present for some time. However, a more sensitive Bone Scan investigation can detect an early onset of bone trauma, indicating either a stress reaction or a more progressed stress fracture.

What is a bone scan?

In the early stages of a stress fracture, an X-Ray may not detect the subtle changes in the bone. Bone scans are used as they detect changes in bone metabolism and are thus more sensitive to bone abnormalities. The patient is injected a couple of hours before the scan with a liquid containing tracers. These little tracers, or markers, flow through the blood stream and are temporarily absorbed by bone they come into contact with. Usually, the markers distribute evenly throughout the bone. However if a stress fracture is present, there may be a large collection of these markers in the one spot (a hot spot), or a reduced number present (a cold spot).

This indicates that there are bone abnormalities in this region. The scan itself is painless, and although scanning the whole body may take up to 30 minutes, smaller areas generally require much less time. Over the following 2-3 days, the markers are naturally released from the body. Although side affects are not common, a rash, swelling or allergic response may occur in rare cases. Also of note is that bone scans are not advised for pregnant women and breast feeding mothers as a precaution due to the radioactive nature of the markers used.

How is a stress fracture treated?

For many stress fractures, treatment may be as simple as a period of rest from the aggravating activity, depending on the site and severity of the fracture. Icing the area for 10 minutes, 3-4 times daily may help to relieve pain and swelling. Following the rest, your physiotherapist will gradually introduce weight bearing exercises aimed at return to your activity of choice.

They are also likely to correct any abnormalities of your movement that may have caused excessive stress through the bone in the first place. Recommendations on your choice of footwear may be appropriate to ensure adequate support and shock absorption. Some stress fractures may require a more aggressive approach such as the use of crutches to prevent weight bearing, or even a cast or surgical fixation if the fracture is thought to be unstable. In the past, the use of ultrasound around fractures was uncommon as people believed it yielded negative results, however recent research is showing that low intensity pulsed ultrasound can significantly improve healing rates. Its use is therefore likely to become common place for stress fracture healing in the near future.

Return to running programs: how to return to running – pain free!

Return to sport programs must be tailored to each individual, and will depend on factors such as the sport played, the level at which it is played, the severity and location of the stress fracture, and the age of the individual. However the concept that the intensity of the exercise must be increased in a gradual manner never changes. Below is an example of a program suitable for a mid to long distance runner.

Phase I: Walking

Walking should be restricted by any pain or apprehension. The intensity gradually increases until an aggressive speed of about 8.5km/hr can be achieved.

Phase II: Plyometrics

This begins with two legged ankle hops/small jumps. Progressions include changing the direction to the side or backwards, and then performing each leg separately. A kilometre run would generally consist of 1000 foot contacts, 500 per foot. Therefore successfully completing a routine of 500 polymeric exercises per foot would be a good indicator the athlete is ready to run for up to a kilometre.

Phase III: Walk/Jog

To progress to this stage, it is important to be pain free, even when pressing on the injured area. The activity duration generally remains constant at 30 minutes; however the ratio of jogging to walking is very low initially. The athlete gradually increased the time spent jogging and subsequently decreases walking duration. Eventually, the aim is to run for the majority of the session, with only a small warm up at the start and cool down at the end.

If any pain presents during or after the session, a return to the level of activity that is pain free is essential. It is also very important to note the location of the pain, the severity, when it presents, and how it feels throughout the course of the day.

Phase IV: Running

This is the final phase of the program where the goal is to return to the previous level of function. It involves gradually increasing the duration and/or the intensity of the training. A general rule however is to only increase the weekly mileage by 10% of the previous week to prevent overloading. Throughout this time, it is important to maintain a stretching program and to keep note of any periods of aggravation.

The most common stress fractures – What are they?

Stress fractures may occur in virtually any bone in the body. The most commonly affected bones are the tibia (shin bone), metatarsals (small bones in the forefoot), fibula, navicular (small bone in the midfoot), femur (thigh bone) and pelvis.

Stress fractures vs. compartment syndrome vs. shin splints

Unlike stress fractures, compartment syndrome due to overuse differs in its clinical presentation. Chronic Compartment syndrome is pain that commences during activity and ceases with rest. It involves an increase in pressure within the compartment of the leg or forearm. The muscles are divided into a number of compartments by fascial sheaths, which are relatively inelastic thickenings of cartilaginous tissue. The increase in pressure may cause local muscle swelling and accumulation of fluid. This impairs the blood supply and causes pain with exertion.

The term ‘shin splints’ has been used to describe pain along the inside border of the tibia (shin bone) commonly experienced by runners. It is now thought that shin splints are a generic term that encompasses many types of pathological disorders. Shin pain generally involves one or more of three processes.

1. Bone stress – A continuum of increased bone damage exists from Bone strain to stress reaction to stress fracture.

2. Inflammation – develops at the insertion of muscles attaching to the shin bones

3. Raised intracompartment pressure - as discussed above.

These three abnormalities can usually be distinguished on the basis of history, examination and investigations. It is important to note that two or all three of these conditions may exist at any one time.

To accurately assess and diagnose your ‘shin pain’ contact us at Beleura Sports and Spinal and book an appointment to see one of our qualified physiotherapists for an accurate diagnosis and further management.

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