Leg length discrepancies can be classified as a structural leg length discrepancy or a functional leg length discrepancy. A structural leg length discrepancy is a hereditary circumstance that one leg is simply longer than the other leg. This is determined if the patient’s pelvis and sacroiliac joints are symmetrical and the leg length is simply due to one leg truly being longer than the other.
Functional leg length discrepancy is diagnosed when there is a torsion or pelvic rotation/ obliquity, commonly a sacroiliac joint dysfunction, which causes one leg to function as though it is longer or shorter than the other. In order to determine if a true structural discrepancy exists, the physical therapist must treat the pelvis and return it to a neutral position before measuring for the leg length discrepancy. Once the pelvis is symmetrical it is determined if the leg length discrepancy remains or if it goes away, if it goes away it is classified as functional. If it remains and has a measurable difference, it is a structural leg length discrepancy.
Leg length discrepancies can be caused by poor alignment of the pelvis or simply because one leg is structurally longer than the other. Regardless of the reason, your body wants to be symmetrical and will do its best to compensate for the length difference. The greater the leg length difference, the earlier the symptoms will present themselves to the patient. Specific diagnoses that coincide with leg length discrepancy include: scoliosis, lumbar herniated discs, sacroiliitis, pelvic obliquity, greater trochanteric bursitis, hip arthritis, piriformis syndrome, patellofemoral syndrome and foot pronation. Other potential causes could be due to an injury (such as a fracture), bone disease, bone tumors, congenital problems (present at birth) or from a neuromuscular problem.
Signs & Symptoms
- An obvious observance of one leg being longer than the other
- Affected posture
- Problems with gait (manner of walking)
- Pain in the lower back, hip, ankle or knee