When teaching, learning, or understanding how to ambulate with a prosthesis, one must comprehend the “Rule of 5.” The pelvis moves 5 degrees in the frontal, sagittal, and longitudinal planes. In other words, it moves just a little side to side, up and down, as well as rotates. This “little bit” of movement becomes a “big deal” if it is not taught and/or understood by the individual using the prosthesis.
Why? Because it will not allow them to use the prosthesis correctly, resulting in chronic injury/breakdown. To simplify this, we will start with the most important 5 degrees of this rule: the lateral shift. When ambulating, or walking, the pelvis moves five degrees in the frontal plane, or laterally shifts, over each limb as the body progresses through space. In order to obtain the correct shift from an individual, they must be comfortable in the socket and trust the limb enough to put their entire body weight through the device. If this is not taught or understood, the individual will laterally flex the trunk over the limb in order to clear the opposite foot as it swings through the air when walking. This trunk leaning movement will put more torque through the sacroiliac joint and cause increased low back pain over time. Individuals that do not shift the proper five degrees over the prosthesis will limp with the classics “amputee walk” because they do not trust the device and/or understand the mechanics.
For new walkers, this “amputee walk” is NORMAL! Human brains are pretty smart; therefore, they do not want to trust the prosthetic device below them and would rather rely on their own trunk stability to move through space. Fortunately, with the right fitting prosthesis and proper training, this trunk lean can improve. With the right weight shift over the prosthesis, an individual with limb loss can have the same gait pattern as someone with two natural limbs.
Stay tuned to learn training tips and techniques to improve the lateral shift over the prosthesis.