A visible notable difference in the length of the lower or upper limbs is called Limb length discrepancy (LLD).
Within the physiological limits, a very minor difference in limb lengths does not affect lifestyle but difference more than the physiological limit can affect gait, posture and cause associated musculoskeletal anomalies.
More than 20 mm of limb length discrepancy can cause muscular compensatory measures in the body, leading to muscular strains and joint pains if not addressed.
LLD causes improper foot biomechanics, thereby affecting the kinetic chain of lower limb joints right from the ankle upto the hip joint and the sacroiliac joint.
The hip, knee and spine have the greatest impact of this LLD, leading to compensatory mechanisms like calcaneum eversion or knee hyperextension or hip rotation in walking, steppage gait, unequal arm swing while walking (one of the LLD indicators).
Other anomalies include decreased stance and stride length in shorter leg, decreased walking or running velocity. This impacts active population like marathon runners or sprinters threefold if the LLD is left uncompensated.
Lower extremity scanogram to determine the exact difference in both the lower limb bone lengths. Or by a physical therapy assessment, wherein a tape is used between two defined bony points (between the ASIS and the medial malleolus) in lying position.
This depends on whether the patient exhibits symptoms or not. Mild (0-30mm), moderate (30-60mm), severe (>60mm).
Mild cases can be treated by adding external heel raises under an orthotic insole or addition of extra sole under the regularly used footwear, in order to compensate for the LLD by a podiatrist/orthotist evaluation, after a lower limb scanogram is done. Physical therapy management will be needed for strengthening and stretching of the affected muscles.
Dr. Janhvi Vayada (Sports Physiotherapist, Mind Your Fitness!)
The team will suggest an integrated plan based on the report.