What Are Stress Fractures?
It takes a lot of effort to support 7 feet 6 inches and the two tons of force generated when NBA basketball star Yao Ming walks or jumps. The cushioning that absorbs the shock of his weight rests on two feet and their joints, ligaments, and muscles. The force of that weight during running can multiply a person's weight by more than12 times. Unfortunately for the Houston Rocket basketball player, his bones couldn't withstand the constant pounding and he developed a stress fracture of the navicular bone of his foot.
The navicular bone helps support the arch of the foot and is a bridge between the bones of the ankle and those of the toes. The bony arch is also supported by the plantar fascia, the thick band of tissue that connects the heel to the front of the foot. The solid bones and the pliable ligaments flex the foot to disperse the forces generated with walking, running, and jumping. But if the force placed on the bone is greater than its ability to withstand it, small micro fractures can occur in the bones that can develop into a stress fracture.
What Causes a Stress Fracture?
A stress fracture is commonly a repetitive or overuse injury of bone. Normally, we think of a fracture or broken bone occurring because of one specific event, but with stress fractures, the damage frequently occurs one step or a jump at a time.
Yao Ming had the misfortune of damaging the navicular bone, which is a unique bone in the foot. Had it been a metatarsal bone, one of the long bones that reach to the toes, the potential for healing is very good. But the navicular bone has a design flaw, poor blood supply. Even with standard treatment of rest and no weight bearing activities, the potential for the navicular bone to heal adequately is poor. In this situation, an operation may be necessary to correct the fracture; which may include a bone graft, cleaning out the bone that didn't heal properly and packing it with healthy bone.
How Long Does a Stress Fracture Take to Heal?
The time to heal a navicular bone fracture is measured in months, not weeks like a "routine" stress fracture. For a professional athlete this can seem like forever. Moreover, it can be career ending.
Athletes are prone to stress fractures as are military personnel. Both groups are highly motivated to ignore pain and continue their training regimen. Unfortunately, the first and sometimes only symptom of a stress fracture is pain. The "no pain, no gain" mantra may do significant harm to the injury. It is critical that athletes and individuals who are at risk for stress fractures listen to changes in their bodies in order to detect physical problems early for optimal healing.
For Yao Ming, the weeks of rest have not healed his navicular fracture and his surgery will require months of healing and rehabilitation. Unfortunately, it seems that it takes more than two feet to support this basketball giant.
Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery
"Overview of stress fractures"