Stress Fractures in the Lower Extremity

In this second installment from my book, The Runner’s Guide to Healthy Feet and Ankles, we will discuss the diagnosis and general treatment of stress fractures in the lower extremity.

The Runner’s Guide to Healthy Feet and Ankles:
Simple Steps to Prevent Injury and Run Stronger

by Dr. Brian W. Fullem et al.

Diagnosis of Stress Fractures

If you have pain that gets worse as your run progresses, then a visit to the podiatrist should be the next step. Remember, stress fractures are often the opposite of soft-tissue injuries, which typically hurt more at the start of a run.

Successful conservative treatment of a stress fracture is extremely dependent on the timely diagnosis and initiation of treatment. Palpation of the injured area and careful documentation of the injury history are key components of making a proper diagnosis. One diagnostic test that works well is having the patient hop on the injured side. This may produce sharp, pinpoint pain if a fracture is present. One may also use the hop test to help determine if the bone is healed enough to return to activity.

Most physicians have radiographs readily available. With the advent of digital X-ray equipment, it’s possible to pick up a stress fracture earlier than ever. It’s important to keep in mind that negative radiographs should almost never rule out a stress fracture. I’ve treated patients with a stress fracture diagnosed via an MRI and/or bone scan where the fracture never revealed itself in a plain radiograph. In the following two images, the patient had pain and swelling but no signs of a fracture in the first X-ray. While the second X-ray of the same patient four weeks later shows the fracture, by this point most of the patient’s pain had disappeared.

Figure 5-2 Figure 5-3
Xrays of feet showing metatarsal stress fracture – before and after

Note almost no change in third metatarsal in the photo on the left. The patient had pain and swelling on top of the foot. In the photo on the right, 4 week later the stress fracture of the third metatarsal is clearly evident. Note the prior surgery on the big toe joint (performed by another Doctor) leading to more stress on the other metatarsals. At the time of the 2nd X-ray most of the pain and swelling was gone. It’s important not to use the results of an X-ray or other test as the only determining factor in regards to healing.

Some bones, such as the navicular or cuboid, may never exhibit radiographic changes in the presence of a stress fracture. While metatarsal stress fractures can sometimes be seen on X-ray, it’s sometimes not until symptoms have subsided that there’s radiographic evidence of bone healing.

If initial radiographs are negative and further testing is required, then the physician can choose among diagnostic ultrasound, MRI, bone scan, CT scanning, or some combination. There’s some debate as to whether MRI or bone scan are better for diagnosing a stress fracture. One study showed that a bone scan is much more sensitive, whereas MRI can be more specific for detecting the exact location for the injury.

One must use caution in interpreting MRI results as bone marrow edema, which is commonly associated with a stress reaction or stress fracture, can also be seen in asymptomatic individuals. A colleague once had a patient who was being evaluated for a sesamoid injury via MRI of the feet and legs as a screening prior to signing a professional soccer contract. The athlete had spent the morning practicing with a lot of ball strikes, and the MRI was read as multiple stress fractures of the metatarsals despite the fact that the patient had no symptoms in that area.

Some doctors have diagnostic ultrasound available in their office. It can be a great way to evaluate soft tissue pathology and can also detect a stress fracture much earlier than a regular X-ray. The value of readings from the units are very much dependent on the expertise of the user.

Figure 5-4

Diagnostic ultrasound of a second metatarsal stress fracture. Image courtesy of Dr. Matt Werd.

A CT scan is a much better option for some bones, such as the navicular or cuboid, and when an MRI is inconclusive and shows an increase of bone marrow edema. Computerized tomography visualizes the cortex of bone much better than MRI.

A variant of the CT scan is the SPECT-CT, which combines nuclear medicine similar to a bone scan with a CT scan. SPECT images are obtained following an injection of a radiopharmaceutical that’s used for bone scans. The injected medication travels to areas where the bone is fractured and will high- light the injured area. The radiopharmaceutical is detected by a gamma camera. The camera or cameras rotate over a 360- degree arc around the patient, allowing for reconstruction of an image in three dimensions.

Figure 5-5

Stress fracture of the medial ankle bone revealed on SPECT-CT. Image courtesy of Dr. Amol Saxena.

General Treatment of Stress Fractures

Stress fractures are one of the few athletic injuries that can require an almost complete cessation of weight-bearing exercise. A good general rule of thumb to guide treatment is that anything that causes pain should be avoided. One exception to this rule has been created with the AlterG treadmill, which creates a vacuum around the runner and allows running at a reduced body weight.

Figure 5-6

Photo courtesy of Dr. Amol Saxena

Bone healing of a fracture generally takes four to six weeks, but there are many factors that influence that time frame. The most important factor is which bone is injured and the location within the bone. For example, a stress fracture in the middle of the second, third and fourth metatarsals can heal and allow a return to running within four weeks. In contrast, a navicular stress fracture requires up to eight weeks of non-weight bearing in a cast, and on average takes at least three months to return to full training. While you’re waiting for a stress fracture to heal, make sure your diet includes a good amount of foods high in calcium and vitamin D.

Return to running is based on the complete absence of pain when pressing on the fracture spot as well as being able to hop on one foot. Run on softer surfaces such as grass if possible and include one to two days off after each run for the first couple of weeks. You might notice some aching in the site of the stress fracture and occasionally pain after a run, which can linger for months after the fracture heals. Be sure to back off if pain increases during a run or if the pain feels similar to the original pain of the stress fracture. My golden rule: If you have a limp when you run, then you shouldn’t be running, as you may end up with a different injury due to compensation.

Extracorporeal Shock Wave Therapy (ESWT) shows promise in reducing healing times for stress fractures. One study examined five athletes who had delayed or non-unions of stress fractures. Once treated with ESWT, each injury showed signicant improvements, leading the study authors to opine that ESWT promotes the formation of new bone and helped these athletes heal faster. ESWT is a noninvasive and effective treatment for resistant stress fractures. Similar to the use of bone stimulation, there are no known negative effects for the use of shock wave therapy for stress fractures. Most physicians do not have a focused shockwave device necessary to treat fractures, almost all portable devices in physicians offices use radial shockwave, which works as well as focused units for almost every other application in the lower extremity.  I have a focused device and hope to publish some literature in the future on stress fractures.

In the next installment we will look in detail at the most common sites of stress fractures in runners and how best to approach treatment.

Dr. Brian Fullem practices at Elite Sports Podiatry in Clearwater, FL. He ran 14:25 for 5K while at Bucknell University. This is the continuation in a series of articles by Dr. Fullem, educating us about injury care, injury prevention & other health topics for athletes at all levels of performance. The following article is the first in a 3-part series of exerpts from Dr. Fullem’s recently published book, The Runner’s Guide to Healthy Feet and Ankles.

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