Leg Length Difference

Introduction

Many people have one leg that is longer or shorter than the other. A study in the US and Sweden discovered that about one-third of people have a difference in the length of their legs that is equal to or greater than 0.4 inches. These small differences usually do not cause issues. However, for a few people with a leg length difference of more than 0.8 inches, this difference in length can impact how they feel and the quality of their life. A study from France is currently the only study available on this topic. It was discovered that for every 1000 people, one person had orthopedic treatment for a difference in leg length of more than 0.8 inches.

What Is Leg Length Difference or Discrepancy?

Lower limb or leg length discrepancy is also known as anisomelia or short-leg syndrome. This is a condition in which the individual has legs that are noticeably in different or unequal lengths. Differences in leg length can either come from birth or be acquired later. When a leg gets shorter, it can happen because the bone is lost or because the growth plate is injured in young patients due to trauma or infection. One leg grows slower in people with congenital or idiopathic leg length differences.

What Are the Types and Causes of Leg Length Discrepancy?

Leg Length Discrepancy (LLD) can be categorized into two main types based on the underlying cause:

Structural Leg Length Discrepancy:

Structural LLD or anatomical leg length difference is primarily due to variations in bone length between the two legs. This can be caused by to:

• Certain congenital conditions.

• Growth plate injuries during childhood or adolescence.

• Fractures or other significant injuries, mainly near the growth plate.

• Surgeries involving bones, such as joint replacement or corrective procedures, may inadvertently cause a leg length discrepancy.

Functional Leg Length Discrepancy:

Functional LLD occurs when there is no actual difference in bone length, but an alignment issue or muscular imbalance creates the appearance of a leg length difference. Causes include:

• Weakness or tightness in some muscles around the hips, knees, or ankles can affect leg alignment and lead to LLD.

• Limitations in joint mobility or stiff joints can result in an uneven gait and apparent leg length differences.

• Abnormal curvature of the spine may lead to uneven hip and leg positioning.

What Are the Conditions and Risks Associated With Lower Limb Length Discrepancy?

A difference in leg lengths can lead to problems that can last for a long time. It is important to consider the risks to the spine, hip joints, and knee joints, as well as painful imbalances in muscle chains.

• Scoliosis - Severe leg length discrepancy or asymmetry in leg positioning can contribute to the development or worsening of scoliosis, an abnormal lateral curvature of the spine.

• Gait Abnormalities - LLD can lead to an uneven walking pattern or gait, resulting in limping, favoring one side, or an abnormal stride.

• Back Pain - The body's attempt to compensate for the discrepancy by altering posture and spine alignment can cause strain on the back muscles and spine, leading to back pain and discomfort.

• Osteoarthritis - Uneven joint loading can accelerate wear and tear in the affected joints, potentially leading to the early onset of osteoarthritis.

• Uneven Muscle Development - LLD can cause differences in how strong and developed the muscles are in each leg. This can make it harder to balance and move properly.

• Problems with Posture - When the body tries to adjust to having legs of different lengths, it can cause an uneven stance, leading to issues with the muscles and bones in other parts of the body.

• Foot Problems - LLD can make feet carry weight unevenly, which can cause issues like plantar fasciitis, foot pain, or other foot-related problems.

• Reduced Abilities - A severe leg length discrepancy can make it difficult for them to do everyday activities, play sports, or exercise.

How Is Leg Length Difference Diagnosed?

Diagnosing leg length discrepancy involves a comprehensive evaluation by an orthopedic surgeon, podiatrist, or physical therapist.

• The diagnostic procedure starts with a detailed medical history, including any past injuries, surgeries, or medical conditions relevant to the leg length difference.

• A physical examination will assess the patient's gait, posture, and alignment. The leg lengths are measured to identify the extent of the discrepancy.

• The gait pattern is assessed to identify any abnormal movements or limping.

• X-rays are commonly used to obtain accurate measurements of the leg bones and to differentiate between structural and functional leg length discrepancies. X-rays can also reveal any other potential underlying bone or joint issues.

• The patient may be evaluated while standing to observe their posture, hip alignment, and any compensatory movements or imbalances.

• Diagnostic tests, like MRI or CT scans, may be done to get a more detailed view of the bones and soft tissues.

How Are Leg Length Differences Treated?

The way to treat leg length differences depends on how bad it is and what is causing it. Treatment aims to lessen symptoms, enhance walking ability, and restore muscle and bone balance. In children who are still growing, measuring the difference in leg length only shows what is happening right now. The treatment choices are mainly made depending on the difference in leg lengths once a person's bones have stopped growing.

Conservative Treatment Approaches

• Shoe Lifts or Insoles - In mild cases, wearing a shoe lift or heel raise on the shorter leg can help equalize the leg lengths and improve gait. Using heel wedge insoles can help fix a leg length difference of up to 0.8 inches. By wearing closed shoes, differences up to 2 inches can be corrected using a sole lift.

• Orthotic Devices - Custom-made orthotics can provide additional support and help correct alignment issues.

• Physiotherapy - Physical therapy uses specific exercises and stretches to fix muscle imbalances, increase flexibility, and strengthen the affected leg.

Surgical Treatment Approaches

• Epiphysiodesis: A surgical procedure called epiphysiodesis may be performed in growing children and adolescents with a significant LLD. It involves partial closure of the growth plate on the longer leg, allowing the shorter leg to catch up in length over time.

• Epiphyseal Stapling: Similar to epiphysiodesis, this surgical technique involves placing staples across the growth plate to slow down the growth of the longer leg and equalize the leg lengths.

• Limb Lengthening: Limb lengthening surgery may be considered in severe structural cases. It involves cutting and gradually pulling the bone apart using an external or internal fixation device to stimulate new bone growth. Over time, the bone regenerates, lengthening the shorter leg.

Conclusion

New medical technology and knowledge about LLD have continuously helped improve how this condition is treated. This brings hope for better results and improved quality of life for people with LLD. People with different leg lengths can live better without discomfort if they get the right diagnosis and care.