Leg length discrepancy (LLD) is a condition where one leg is measurably shorter than the other or appears shorter due to other body issues. Even slight differences can influence movement and body mechanics. Significant LLD can lead to physical challenges. This article overviews LLD, from recognition to management.
Understanding Leg Length Discrepancy
LLD is categorized into structural and functional types. Structural LLD (anatomical LLD) refers to an actual difference in femur (thigh bone) or tibia (shin bone) length. It can arise from congenital conditions, growth plate injuries, or fractures that heal with bone shortening.
Functional LLD occurs when bones are equal length, but other factors make one leg appear shorter. This can stem from pelvic tilt, scoliosis, muscle imbalances, joint contractures, or excessive foot pronation. This distinction guides diagnosis and management.
Identifying the Discrepancy
Recognizing LLD often begins with subtle signs. Common indicators include a noticeable limp or uneven gait, where one side of the body dips lower. Individuals might also observe uneven shoulders or hips, or experience persistent pain in the lower back, hips, or knees. Imbalance or constantly shifting weight can also suggest a discrepancy.
Professional diagnosis determines LLD presence and type. A healthcare professional conducts a physical examination, including visual inspection of posture and symmetry. Measuring tape methods provide an initial estimate. For precise measurements, imaging techniques like full-length standing X-rays (scanograms) commonly measure bone lengths and identify the exact discrepancy.
Why Addressing It Is Important
Leaving significant LLD unaddressed can lead to biomechanical issues. The body compensates for unevenness, often resulting in chronic pain and musculoskeletal dysfunction. Discomfort may occur in the lower back, hips, knees, and ankles as these joints bear uneven loads.
Altered biomechanics can affect walking patterns, leading to gait abnormalities. This results in an inefficient or unbalanced stride, increasing energy expenditure and potentially causing fatigue. Ongoing compensation can lead to postural problems, including scoliosis or pelvic obliquity. Uncorrected LLD can also increase joint wear, potentially accelerating degenerative conditions like osteoarthritis in the hip or knee due to abnormal loading.
Non-Surgical Approaches
For many with LLD, non-surgical approaches are primary and effective. One common method involves shoe lifts or orthotics, external or internal inserts designed to equalize leg length. External shoe lifts are added to the shoe sole; internal inserts are placed inside for subtle elevation. The type and height of the lift depend on the discrepancy, with lifts up to 1 cm often placed inside, and larger lifts added underneath the shoe.
Physical therapy plays a role, particularly for functional LLD or to address compensatory issues from structural discrepancies. Therapists design programs including exercises to strengthen weakened and stretch tight muscles, improving flexibility and reducing imbalances. Gait training helps re-educate walking patterns, promoting efficient and balanced stride. Posture correction exercises alleviate strain and improve body alignment.
Lifestyle adjustments can contribute to managing symptoms and preventing complications. This might involve ergonomic considerations, such as adjusting workstation setups for balanced posture, or modifying activities that exacerbate discomfort. Avoiding prolonged standing or activities that put uneven stress on the legs can be beneficial. These non-surgical methods are typically recommended for smaller discrepancies (under 2 centimeters) or as the initial management strategy.
Surgical Options
For significant LLD, or when non-surgical methods haven’t provided adequate relief, surgical interventions may be considered. Surgery is generally reserved for discrepancies over 2 to 2.5 centimeters, especially if they cause substantial functional impairment or pain. Surgical choice depends on patient age, discrepancy magnitude, and growth plate status.
One common surgical approach for children with open growth plates is epiphysiodesis. This procedure involves surgically slowing or stopping the longer leg’s growth plate, allowing the shorter leg to catch up as the child grows. For adults or children whose growth plates have closed, limb lengthening is a procedure where the shorter bone is gradually extended, typically using external fixators or internal rods adjusted to stimulate new bone formation.
Conversely, limb shortening is an option for cases where the longer leg is longer, though less common than lengthening. This involves removing a section of bone from the longer limb to reduce the discrepancy. All surgical options require a significant recovery, often involving physical therapy, and carry potential risks such as infection, nerve damage, blood clots, or bone healing issues. The decision for surgery is made after careful consideration and discussion with a medical professional.