Limb Length Discrepancy
A limb length discrepancy is a condition that occurs when one leg is shorter than the other. The discrepancy can either be structural, functional or a combination of both and can vary anywhere between 4mm to 60mm. Limb length discrepancies 20mm or more are usually problematic resulting in compensatory posture and walking patterns.
Structural (actual) discrepancy occurs when:
- Either the upper (femur) or lower (tibia) bone in one leg is actually shorter than that of the other leg.
Structural discrepancies can result from a growth plate injury during childhood or adolescence, fractures, or genetic and acquired conditions that affect bone growth. Some fractures can lead to overgrowth of bone during the healing process, resulting in longer than normal bone. Knee or hip replacement can result in a leg length discrepancy.
Functional (apparent) discrepancy usually occurs as a result of:
- Muscular weakness or inflexibility, at the pelvis or foot and ankle.
Over a number of years, one side of the spine, and muscle structure supporting it, may develop more strongly than the other resulting in scoliosis. Overuse of one side such as sleeping or carrying items on one side; or lifting suitcases or carrying children to one side.
- Head tilt and shoulder drop, often toward longer leg.
- Iliotibial band friction syndrome (pain on the outside or lateral part of the knee).
- Piriformis syndrome (buttock pain that pain runs down the back of the leg).
- Asymmetrical arm swing.
- One leg is obviously shorter than the other.
- Pelvis higher on the longer side.
- Gait problems, such as limping, toe-walking, or rotation of the leg.
- A knee that’s chronically hyper extended on the short side and flexed on the long side.
- Pain in the back hip, knee, foot, and/or ankle.
- Symptoms affecting the lower limb that has a structural discrepancy usually appear first on the long leg side and include buttock pain, arthritis of the knee or hip, patellar tendonitis, patellofemoral pain syndrome, plantar fasciitis, medial tibial stress syndrome or metatarsalgia.
- Symptoms of the short leg include iliotibial band friction syndrome with lateral knee pain, trochanteric bursitis, sacroiliac discomfort, Achilles tendonitis and cuboid syndrome.
- If the patient just has a functional Leg Length Discrepancy, the symptoms will usually appear on the short side first and include plantar fasciitis, medial tibial stress syndrome, patellofemoral pain syndrome, iliotibial band syndrome, ipsilateral sacroiliac discomfort with contralateral low back pain, and secondary psoasitis.
At Mint Foot Care Podiatry, we diagnose this condition by taking a comprehensive history, performing a leg measurement, biomechanical assessment and video gait analysis. The podiatrist may prescribe diagnostic imaging such as X-Rays and/or a CT scan.
Based on the findings a combination of treatment options may be prescribed including:
- Proper fitting and supportive footwear recommendations with an external heel raise if the discrepancy is greater than 20mm.
- Custom made orthotic therapy – orthotics may be prescribed to address any biomechanical factors such as over pronation.
- Heel lifts.
- Prescribed stretching and strengthening exercises.