Leg Length Discrepancy
For the efficient movement of the human body, there must be a well-aligned musculoskeletal system, in order to achieve effective movement and normal energy expenditure avoiding stress and fatigue. Unfortunately, most of us are not functionally or structurally symmetrical and so this can cause many symptoms within the body due to uneven leg lengths. Many of these symptoms are treatable if the cause and type of LLD are recognised early on.
Leg length discrepancy is a common occurrence in the pediatric and adult population with statistics showing that between 90-95.5% of the population is affected. A survey conducted at the Children’s Hospital in Boston showed that 93% had a leg length discrepancy. A leg length discrepancy can have a profound effect on the locomotor system affecting the spine, sacroiliac and hip joints as well as the foot. A difference of greater than 1cm affects normal body alignment, but in a sedentary person a small difference may have little to no effect until they may increase his/her level of exercise then symptoms may arise.
There are 2 types of LLD: Structural and Functional.
1. Structural: is due to the actual difference in length of femur/tibia. The cause may be congenital, post-surgical or trauma e.g. knee replacement or fracture.
2. Functional: bony components equal in length but function asymmetrical. This asymmetry in function may be from hip flexion contractures, previous injury, excessive unilateral foot pronation/supination, pelvic/anomaly (scoliosis), hyperextension of knee/ankle and knee varum/valgum.
Sometimes it is difficult to differentiate which type as it is not unusual to have both arise together.
Symptoms are worse on the LONGer side, due to increase stance time and over-pronation on the limb.
Potential compensations at certain joints in the lower extremity:
- Subtalar joint: pronation (flattened arch) of the longer leg, supination ( raised arch) of the shorter leg
- Ankle joint: plantarflexion of the shorter leg (pointing towards the ground)
- Knee joint: hyperextension of the long leg or knee flexed more long side
- Uneven arm swing or shoulder tilt
Signs and symptoms of LLD:
- Low back pain
- Hip pain/OA
- Pronation of Subtalar joint
- The tendency for body weight to be shifted to the longer side
- Asymmetric pelvic rotation
- Achilles tendonitis
- Early heel lift
- Varus/valgus knee
Parents are usually the first to detect there is an issue with leg length or their secondary symptoms, follower by teachers or when a child goes through a spinal screening programme at school.
To check for LLD the Podiatrist will conduct a thorough physical examination and use specific tests to confirm or diagnosis a discrepancy in length.
This entails tape measurements from the Anterior Superior iliac spine (front of Hip) to the medial malleolus (inner ankle) several times and taking an average length can provide dependable clinical data says Beattie et al, 1990. The presence of a leg length discrepancy can be observed during a Podiatrist’s gait analysis in the clinic, these can include signs of shoulder tilt, unequal arm swing, pelvic tilt, excessive knee flexion or excessive high/low arch of the foot on one side. TIP > So this can be an observation that you can look out for that may be indicating that =there is a leg length discrepancy present and further examination by a specialist is needed.
X-rays are a useful tool used to determine leg length structurally, information on the bone quality of the limbs and any anatomical anomalies. This provides accurate and quantitative data on leg length assessment.
Treatment for LLD includes:
- Heel lifts within customized orthotics
- Shoe modifications
- Stretching contracted muscle groups
- Surgical procedures