No acronym strikes as much anxiety into the heart of an orthopedic patient like N.W.B. or Non Weight Bearing. N.W.B. refers to the restriction an orthopedic surgeon places on a patient following surgery. But why do orthopedic surgeons torture their patients with the temporary commandment: thou shalt not set thy foot on the floor?
It comes down to one very simple reason, tissue healing. A variety of tissues benefit from limiting the stress of weight bearing during the healing period. Wounds heal better when they are not stressed by walking. Studies show that patients can benefit greatly by avoiding early weight bearing after Achilles Tendon surgery, one of the most difficult areas to heal.
Most commonly, surgeons limit weight-bearing following fracture repair or foot/ankle fusion surgery. In these surgeries, bone surfaces are squeezed together tightly and held in proper alignment. Once the first cast/splint is placed, and the surgeon leaves the OR to talk to the family, the race is on. Will the bones heal, or will the metal used to hold the bones in place break first? Many factors can be adjusted by the surgeon, including:
- Titanium or Stainless Steel Screws
- Thicker Plates and Screws
- Multiple Plate and Screw Formations
- Locking Screws
- Minimally Invasive Placement
- Bone Graft
- Bone Stimulators
The choices are extensive. But, the most powerful thing that helps to heal is a cooperative patient.
The action of placing the foot on the ground creates a variety of forces going in different directions: UP, DOWN, RIGHT, LEFT, FORWARD, BACKWARD, AND ROTATIONAL. These forces stress a newly fixed interface. If the interface is excessively stressed, the hardware can fail, or the bone can break around the hardware. This causes the bones to lose alignment and the formation of a malunion (bones healing in the wrong place). Sometimes, the bones don’t heal at all. If there is too much motion, the body misinterprets the forces, and instead of healing with bone, it heals the interface with joint-like characteristics. This is known as a nonunion. In either condition, malunion or nonunion, the race is over, and the patient and the surgeon have lost.
As a surgeon, my goal is to find surgical techniques and instrumentation that not only allow early weight-bearing but benefit from controlled, protected weight bearing. Examples include correction of bunions with stable bone cuts that heal faster with walking and ankle fracture repair with minimally invasive and specialized plating techniques that neutralize the weight bearing forces. Regardless of skill, some surgeries cannot be best performed without limiting weight bearing. Triple arthrodesis, Osteoarticular transplantation surgery (otherwise known as cartilage restoration), and Total Ankle Replacement are some examples.
When I have to resort to non weight bearing, I encourage the patient to partner with me in the healing process. I explain why it is essential to avoid walking on their foot, and I am always looking to find ways of making it easier to survive those weeks of N.W.B. Crutches and walkers can only get you so far, and wheelchairs are very limiting. Knee scooters are a great alternative option. They give the patient much more freedom and ease of movement when they are forced to keep weight off a healing foot.
It is true that some patients are their own worst enemy (namely those who don’t follow their doctor’s orders). However, a patient armed with knowledge is always more likely to be an ally in the Amazing Healing Race.