Jill Murphy, DPT, LAT, CSCS
Stress fractures are THE dreaded injury for many sporting populations and in military recruits, but the highest incidence of stress fractures occur in distance runners who have a reported 15% incidence of stress fractures. While there are many gadgets, gizmos, and special training programs intended to reduce stress fractures, the topic is actually much more complex than that.
What is a stress fracture? Our bones consist of living structures called cells. There is a constant turn-over of our old bone by special bone-eating cells called osteocytes. The job of these cells is to destroy old bone tissue that is then replaced by new, healthy bone cells formed by osteoclasts. In normal, health bones, there is a local balance of the bone destroying and bone building cells in the bone remodeling process.
When a stress fracture occurs, the delicate balance between these bone cells has been altered by too much micro (mini) trauma typically over an extended period of time. The remodeling process becomes accelerated, and the osteoblasts tasked with building new bone simply cannot keep up with the osteoclasts’ activity, and the bone becomes weakened in the outer edges of the bone. Eventually a crack in the bone cortex occurs and becomes a source of gradually increasing pain. At times pain can be felt from over-doing a work-out on one day. If there is a pin-point area of pain after doing an unusual amount of running or even walking on your feet to which your bone is not accustomed, you need to rest for several days and ice the area until the tenderness and swelling is gone. If you do not rest and you continue your advanced work-out activities, this area of bony sensitivity may develop very quickly into an actual bone fracture or fissure, necessitating more aggressive care like a walking boot and complete cessation of activity on your feet. Because stress fractures occur from excess time in weight bearing, they tend to occur in long bones of the lower leg like the tibia or fibula, in small bones in the foot (metatarsals), and can more rarely occur in other areas of weight bearing like the pelvis, femur, sacrum and spine. Stress fractures statistically tend to occur a bit more often in females than males participating in the same sporting or military training activities. Caucasians also show a slightly higher risk of stress fractures compared with African American and Hispanic military recruits, believed to be due to a lower overall bone density in Caucasians. There are also reported cases of bone insufficiency creating stress fractures in the pelvis for patients undergoing radiation for cancer treatment, as the bone becomes weakened from the effects of focused, repetitive radiation.
The treatment for stress fractures is to take at least three weeks off and rest to allow the normal bone balance to be restored, for the fissure to be bridged and later closed through normal bone cell activity. If the area is not protected and rested, a true fracture can occur along the fissure lines. Sometimes there are multiple fissures present, and the bone can actually shatter into pieces if weight bearing activity is aggressively continued, require surgical fixation for appropriate healing. Some ways to expedite healing other than non-weight bearing include ice and elevation, bone stimulators, calcium and vitamin D supplementation, and physical therapy to address any other issues like muscle tightness, weakness, biomechanical flaws in running mechanics, or pain in adjacent areas. Alternative, non-weight bearing activities may be continued, such as swimming, treading water, underwater jogging, and biking, unless complete rest is indicated.
There are some ways other than simply avoiding overuse in weight bearing to reduce the risk of stress fractures. For women, addressing any irregularities with the menstrual cycle can impact bone health and increase risk of fracture. Combine this problem with women who put in lots of repetitive training time may have the silent problem of osteopenia or osteoporosis, with already weakened bone ripe for a stress fracture.
Ensuring adequate intake of calcium and vitamin D in the diet is also a great way to prevent stress fractures. Vegans and vegetarians are at a high risk of inadequate calcium intake, leading to bones that are weaker and more susceptible to fracture. Note that some common medications such as omeprazole reduce the body’s ability to absorb calcium, leading to weaker bones and an increased risk of stress fractures as well. Avoiding and/or treating any eating disorders is also very important, as a link has been shown between eating disorders and low muscle mass to osteopenia with weakened bones increasing the risk of stress fractures.
Physical therapy is an excellent idea for people at a higher risk of stress fractures, as well as those with poor running or marching gait mechanics, flat feet, or any other foot abnormalities that may be improved with the help of custom foot orthotics and special exercises to improve strength and flexibility in the lower leg and hip. Physical therapists can work to improve running mechanics, assist with specific footwear selection based on the patient’s individual characteristics, gait pattern, and foot type, and also treat shin splints and bony hot spots before they become full blown stress fractures. Sports medicine professionals like physical therapists and athletic trainers serve as excellent guides in returning patients back to activity in a slow, step-wise fashion, and help modify training programs and substitute non-weight bearing activities for the current weight bearing training program.
The best way to prevent stress fractures is to follow reasonable training programs that follow the laws of common sense. Limiting increases in distance or intensity of weight bearing activities by 10% each week (increasing only one variable at a time) and having a solid running base before participating in a competitive school sport season or marathon training program. Cross training to avoid weight bearing activities for more than 4 days per week is also recommended, especially for people who have suffered from stress fractures in the past. There are no wraps, sleeves, or other devices that can prevent a stress fracture. Be careful with hill training, and running on road bevels. Avoid hard training surfaces; try to modify the training surface, running on the shoulder of the road, a pebble path, or grass when possible to reduce bony impact. If you are concerned you may be at risk or have a stress fracture, seek medical assistance as soon as possible to guide you in a treatment plan to minimize the impact to your bone health AND to your training schedule.
Runners are not the only athletes who tend to experience stress fractures. Those training in the military, gymnists, dancers, and even basketball and volleyball players- any activities requiring high volume of repetitive activity can lead to bone stress in the lower extremities and in the spine. Golfers are at risk of stress fractures in the ribs, while tennis players may also suffer from stress fractures to the spine. Signs and symptoms are pin-point areas of pain in bone that are constant, increasing with the activity or movement (like spine extension or back-bending) that first created the bone stress. The key is to pay attention to the pain right away, ice, and modify activity (rest!) to reduce bone stress to prevent the stress fracture to begin with. If the pain continues and a stress fracture appears (remember it takes 3 weeks for a plain Xray to show a stress fracture, but bone scans can demonstrate hot spots much earlier), seek medical attention, with possible boot, splints, or braces applied to rest and protect the stress fracture to allow full healing.
Early identification of these injuries and early treatment and activity modification are the key to reducing playing time lost from stress fractures. MotionWorks Physical Therapy always has free injury screenings available by appointment with our physical therapists and athletic trainers and we can check for these types of injuries and guide athletes in the next steps to address their injury. Call 920-215-2050 to schedule your appointment today.
References
• Romani, WA et al. Mechanisms and management of stress fractures in physical active persons. J Athletic Training. 2002; 37 (3): 306-314.
• Chan S, et al. Pelvic insufficiency fractures in women following radiation treatment: a case series. Ann Palliat Med. 2016 May 27 (Epub ahead of print).