Monday, July 20, 2009
It takes a lot of effort to support 7 feet 6 inches and the two tons of force generated when Yao Ming walks or jumps. That cushioning rests on two feet and the joints, ligaments and muscles that absorb the shock that 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 helps support the arch of the foot and is a bridge between the ankle bones and those of the toes. The bony arch is help by the plantar fascia, the thick band of tissue that connects the heel to the toes and together, 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 and the potential start of a stress fracture occurs.
A stress fracture can be thought of as a repetitive or overuse injury of bone. Normally, we think of a fracture or broken bone happening because of one specific event, but with stress fractures, the damage occurs a step or a jump at a time.
Bone is constantly evolving to meet the needs of the body. If a bone isn’t used, calcium leeches out of it and it becomes osteoporotic. If it is challenged, more calcium is laid down to protect it and the bone becomes denser. With a stress fracture, the bone loses its ability to recuperate in time to withstand the next small trauma. And if enough micro fractures merge together, the bone can become damaged.
Yao Ming had the misfortune of damaging the navicular bone. 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 has a design flaw and its blood supply isn’t very good. Even with standard treatment of rest and no weight bearing, the potential is high that the navicular won’t heal and a non-union will occur.
Non–unions are on the complications of any fracture and is especially the case in bones where the ability of the body to deliver blood’s nutrients. The consequence is an operation to fix the fracture. It may include a bone graft, cleaning out the bone that didn’t heal and packing it with healthy bone.
The time to heal is measured in months and not weeks like a “routine” stress fracture. That may seem like a long time but for a pro athlete, it will feel like forever and perhaps 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 and the no pain, no gain mantra may do significant harm. Ultimately, knowing one’s body is the best way of telling the difference.
For Yao Ming, the weeks of rest have not healed his fracture and his surgery will cost him months of healing and rehabilitation. It seems that it takes more than too feet to be able to support a gentle giant.