So you’ve got a bone stress injury (BSI). Perhaps your doctor has given you a timeline for when the bone should be completely healed, at which point you can return to your beloved sport of running.
Certainly a stress fracture or reaction is not “good news” by any stretch of the imagination, but bone stress injuries do have the advantage of having a relatively standard healing timeline, depending upon severity of the injury. Bone is also the only tissue in the body that heals 100%, meaning that the new bone tissue is just as strong post-injury as it was pre-injury. This is not the case with ligaments, muscles, and tendons, which heal back to about 97% when injured.
Far too often I see runners take the time off from running and then return back without ever investigating the “why” behind the injury. This phenomenon does not only occur with stress fractures, but I find it more common since it is a fact that bone heals more predictably than other tissues of the body.Investigating the cause of the injury is important not only in treating the issue at hand, but also to prevent recurrence– of the same injury or a new one.
To better understand why BSI’s occur, I’ll review some basics about bone metabolism. Our bones are constantly remodeling, and there is a balance of bone building and bone breakdown. The rate of breakdown vs. building is determined by nutritional status, vitamin and mineral availability, hormone levels, and stresses placed on the bone. Simply put, if the stress you place on your bones through activity is greater than your body’s ability to repair them, injury occurs. This rings true with all overuse injuries.
I highly recommend that in these situations runners seek out a sports medicine physician, preferably one who specializes in runners, to help put the pieces of the injury puzzle together. All injuries are multifactorial, but BSI’s in particular often have another physiologic or systemic cause. Your doctor will order the tests that he/she feels are appropriate based on your history, symptomology, and experience as a runner. Additionally, they will likely recommend PT (hey, that’s me!) to delve deep into your range of motion, strength, and biomechanics.
Let’s review some of these tests and why they are relevant to the BSI puzzle.
DEXA (Dual-Energy X-Ray Absorptiometry) Scan– This is a special type of X-ray that assesses bone mineral density throughout the body and can provide information of any bones that are more susceptible to injury. This is particularly useful for perimenopausal women, anybody with a history of eating disorder or energy deficiency, and older individuals.
CBC (Complete Blood Count) – While all of the information provided will be meaningful to overall health, here we are most interested in the measures related to iron: hemoglobin, hematocrit, and Ferritin. Iron is a key component to oxygen transport and therefore athletic performance, but also plays a role in Vitamin D metabolism. Low Iron levels can lead to early muscular fatigue, which could place more stress on bony tissue.
Vitamin D– Vitamin D functions to help with calcium absorption and bone mineralization, thus maintaining bone density. Vitamin D also plays a role in muscle function, which again can help support high intensity running.
Hormone Panel–Estrogen levels are closely tied to bone health, and is why many women experience BSI’s during and after the menopausal period. Estrogen is directly responsible for the activity of osteoblasts, which are the cells that produce bone.
Gait Analysis– There are certain landing patterns and patterns of weakness that are observed frequently in individuals with BSI’s. These include, but are not limited to: Crossing midline at initial contact, overstriding with a straight knee at initial contact, poor control of pronation, and poor control of hip rotation. These patterns indicate poor absorption of force through the joints and bones, which can lead to bone breakdown over the miles. There are strength programs and drills that can be recommended based on the information gathered that ultimately can help decrease risk for another BSI.
The value to checking all the boxes prior to returning to training is innumerable. It will be well worth it in the long run (pun intended).
Keep going, you got this!
Dr. Kacy Seynders, PT, DPT, OCS