A walking boot (CAM walker) is a tall orthopedic device prescribed to immobilize and protect the lower leg, ankle, or foot following injury or surgery. This design elevates the injured limb, creating a significant disparity in leg length compared to the uninjured side. This artificial limb length discrepancy (LLD) disrupts the body’s natural alignment and walking pattern. A shoe lift or leveler worn on the uninjured foot is the standard solution to restore balance and symmetry.
The Biomechanical Necessity of Leg Length Equalization
The height difference created by the walking boot immediately forces the body into an unnatural, compensatory gait pattern. This unevenness causes the pelvis to drop on the side of the shorter, uninjured leg, leading to a lateral bending of the lumbar spine. This misalignment shifts the body’s center of gravity and introduces abnormal forces across the lower kinetic chain.
Research shows that LLD significantly alters lower limb biomechanics, increasing mechanical asymmetry at the hip and knee joints during walking. The hip on the booted side may experience increased flexion and abduction moments, while the knee on the uninjured side takes on uneven loading that can lead to joint strain. Even a discrepancy exceeding one inch, common with a typical walking boot, can cause a noticeable limp and contribute to secondary issues. Equalizing the limb length distributes the load more evenly, helping to prevent pain in the lower back, hip, and knee caused by the uneven stride.
Choosing the Right Shoe Leveler
Selecting the correct device for the uninjured foot is necessary for effective equalization, as the goal is to precisely match the height of the walking boot’s sole. Walking boots vary, but the sole typically adds between 0.5 to 1.5 inches to the limb length. To determine the required lift, measure the height of the boot’s sole at its thickest point, usually the heel.
Commercial shoe levelers, such as adjustable models, are designed to accommodate this range. These devices feature multiple removable layers, allowing for incremental height adjustments to achieve a near-perfect match. The leveler is secured to the outside of the regular shoe and is sized based on the length of the shoe’s sole, not the wearer’s shoe size. If the exact height is between two sizes, choosing a leveler that slightly under-corrects is recommended to ensure the foot is not elevated too high.
Safe Application and Gait Adjustment
The shoe leveler should be worn on a securely fastened, closed-toe athletic shoe on the uninjured foot to provide a stable base. Application involves strapping the leveler firmly over the sole of the shoe, often utilizing Velcro or hook-and-loop fasteners to prevent slippage during ambulation. It is important to ensure all straps are snug so the leveler does not shift, as instability can increase the risk of a fall.
Once the height is equalized, the wearer should consciously adjust their walking pattern, focusing on taking slower, deliberate steps that promote a symmetrical stride. A physical therapist or physician can offer specific guidance on restoring a more natural heel-to-toe gait, especially after a period of walking with the discrepancy. The leveler should be used only when the patient is weight-bearing and ambulating, and should be regularly inspected for signs of wear and tear, such as compromised straps or worn treads, which could affect stability and safety. If hip, knee, or back pain persists despite using the leveler, a medical professional should be consulted to reassess the device’s fit or the underlying gait mechanics.