Non weight bearing or nil weight bearing or simply NWB is not putting weight on a particular part of the body. Since, weight of the body is primarily born by our legs, the restriction of non weight bearing is generally applied after leg injuries or surgeries. Non weight bearing is more important than any other treatment for proper recovery from leg and knee injuries. Failure to understand the significance of this simple restriction, can lead to disastrous outcomes from even simple fractures or surgeries on the leg. Hence, it is very important to understand what is non weight bearing and follow it religiously to prevent complications.
Non Weight Bearing Types
Although, non weight bearing simply means, not to touch the foot on ground while walking. There are grades of non weight bearing where some degree of contact with the ground is permissible.
- Strict non weight bearing means absolutely no contact between foot and ground. This can only be feasible with the help of Crutches (Video 1) or a Walker (Picture 1). Simple leg injuries, like an ankle sprain or fibula fracture, which seem pretty trivial, benefit greatly with strict non weight bearing and can complicate if this is not followed properly. Strict non weight bearing is generally applied for the first 4-6 weeks after any knee injury or sprain involving the leg.
Picture 1: Non Weight Bearing Walker
(Source: Lumex Folding Walker)
- Partial weight bearing allows some degree of contact between the foot and the ground, but not for bearing the weight of the body. After 4-6 weeks of strict non weight bearing, partial weight bearing is applied to get unused muscles and bones ready to bear the weight of the body. During this stage the process of bone healing after injury or surgery is not fully complete. Hence, a couple of weeks of partial weight bearing helps the newly formed bone to gradually adjust to the stresses of weight bearing.
- Full weight bearing is when a previously injured person, is asked to put his normal weight on the involved leg. Non weight bearing with Crutches or a Walker beyond 8 weeks out of fear, pain, or anxiety, is completely useless and leads to thinning of leg muscles and increased inability to walk without support. Hence, it is strongly advised to follow weight bearing instructions of a qualified orthopedic doctor or physical therapist, without any fear or apprehension.
Video 1: Non Weight Bearing Crutches
(Source: Youtube )
Non Weight Bearing Exercises
It is frequently observed that during non weight bearing, people tend to not use the entire leg and thigh with fear of causing re-injury. Though, some parts need strict immobilization and a generally put into a non weight bearing cast or non weight bearing boot as per the type and extent of injury. Being cautious always prevents most of the complications like displacements or loosening of bone screws. However, the part of leg outside the non weight bearing cast unnecessarily suffers from the consequences of inactivity. Inactivity of leg muscles during the non weight bearing period causes thinning of the leg muscles due to non use (disuse atrophy). Non weight bearing leg exercises (Video 2) are simple bedside exercises, which help to keep the leg muscles active and prevent thinning of leg muscles during this period. There are 2 types of non weight bearing leg exercises,
- Isotonic non weight bearing exercises where the muscles are used for the complete range of movement that is permissible depending on the injury (Normal section of Video 2). These exercises help in maintaining the length of the muscles and preventing contractures (muscle shortening causing joint stiffness).
- Isometric non weight bearing exercises where the muscles are made taut and then relaxed in a repetitive manner (Advanced section of Video 2). These exercises help in maintaining the strength of the leg muscles and preventing weakness.
Video 2: Non Weight Bearing Knee Exercises
(Normal = Isotonic & Advanced = Isometric)
(Source: Youtube )
Yoga with non weight bearing leg or non weight bearing aerobic activity can also form an important part of non weight bearing exercise regime during the period of non weight bearing.
Non Weight Bearing Exercises Pain
Pain while performing non weight bearing exercises has to be dealt with very carefully. Mild discomfort while performing these exercises is natural because of the stretching of the stiff muscles and soft tissues. But pain at the surgical site or at the site of injury, is an alarming sign and demands prompt discontinuation of the exercise. Continued pain despite adequate rest after a particular non weight bearing exercise session can be a sign of re-injury. Hence, it should be followed by an evaluation by your orthopedist to check the current status of the area of surgery or injury.
Non weight bearing exercises are an excellent way to protect the legs from stiffness, contractures, and weakness, after the immobilization following an injury or surgery. Yet a proper guidance of a physical therapist is essential for preventing re-injury and other complications.