Possible consequences of a leg length difference

The pelvis is the pivotal point of all movements involving walking and standing. It anchors the legs to the trunk and is firmly connected to the lumbar and sacral spine, providing stability in the middle of the body. If one leg is longer than the other and a permanent tilting of the pelvis occurs, this has an effect on normal posture.

By trying to compensate for the difference through the muscles, tension is created in the cervical or lumbar spine, which can even result in headache or jaw pain. The incorrect posture in the spinal column results in pain as well as faster wear and tear of the vertebral joints and intervertebral discs. In the worst case, the curvature of the spine can progress to scoliosis.

Frequently, those affected compensate unconsciously. In the gait pattern, a greater load on the toes of the shorter leg can then be observed. The longer the difference in leg length persists, the more a functional limitation of leg and hip mobility can be observed.

Since the cartilages of the joints are also loaded differently due to the different load, an unequal wear and tear of the cartilage occurs. As a long-term consequence, arthrosis may be possible. At the hip joint, depending on the leg length difference, an inequality in the femoral head canopy results.

On the side of the shorter leg, the femoral head is more strongly covered by the acetabulum, which results in an increase in the angle between the femoral shaft and the neck of the femur. This can be made visible when measuring the leg length difference. This relieves the hip on this side.

An additional relief of the hip joint on the side of the shorter leg is achieved by the fact that when the limp is shortened, the upper body is shifted more to the side of the shorter leg, thus shortening the lever arm of the body’s centre of gravity, or the load arm. On the longer side, a functional change in the angle of the hip joint (coxa valga) occurs due to a reduction in the angle between the femoral shaft and the neck of the femur, with increased load and increased risk of arthrosis. More muscle work must be done by the hip abductors because of the increased distance between the origin and insertion of the muscles.

This can lead to chronic bursitis (bursitis), as the pelvic tibial tendon plate (tractus iliotibialis) presses more on the greater trochanter major. The musculature is influenced by differences in leg length. Electromyographic (electromyography) measurements show that even a slight difference in leg length of one to two centimetres leads to increased asymmetrical muscle activity in the various muscle groups on the trunk and lower extremities.

Subjectively, muscle fatigue pain can be felt. A slight difference in leg length rarely causes pain, as it is well compensated for. A slight pelvic obliquity is usually hardly noticeable.

However, it can also cause a shortening limp and a balancing spinal curvature (scoloiosis). An individual insole fitting is advisable. Approximately 66% of the population have a leg length difference of less than one centimetre.

A larger leg length difference can have serious consequences for the muscular and skeletal system. This is followed by pelvic obliquity and a curvature of the lumbar spine (lumbar scoliosis) to compensate. This can be followed in later stages by a countercurvature of the thoracic and cervical spine (cervicothoracic scoliosis).

In 90% of all cases, these false curvatures of the spinal column (scoliosis) become fixed and remain in place. To compensate for the difference in leg length, an arched foot position is created on the shorter side and the knee on the longer side is bent. The consequences of the leg length difference are incorrect loading of the spine and the hip joint. Especially in the lumbar spine, there is increased wear and tear of the intervertebral discs, increased formation of bone mass (osteophyte formation) and arthrosis of the small vertebral joints (spondylarthrosis).