Unequal leg length

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Unequal leg length
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A girl with a congenital, structural difference in leg lengths is walking in a clinic.
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Unequal leg length (also termed leg length inequality, LLI or leg length discrepancy, LLD) is where the legs are either different lengths or appear to be different lengths because of misalignment. The condition has been estimated to affect between 40% and 70% of the population, with at least 0.1% having a difference greater than 20 mm. [1]



There are two main types of leg length inequalities:

Diagnosis and workup

X-rays for leg length measurement. Leg length measurement on X-ray.jpg
X-rays for leg length measurement.

Unequal leg length in children is frequently first suspected by parents noticing a limp that appears to be getting worse. [3] The standard workup in children is a thorough physical examination, including observing the child while walking and running. [3] Also, at least in United States, standard workup in children also includes X-rays to quantify actual length of the bones of the legs. [3]

On X-rays, there is generally measurement of both the femur and the tibia, as well as both combined. [4] Various measuring points for these have been suggested, but a functional method is to measure the distances between joint surfaces: [4]

A leg length difference can result from a pelvic torsion.

Abnormal (gravity drive) pronation will drive the innominate bones forward (anteriorly). The forward rotation of the innominate will shorten the leg (See Rothbart 2006). The more pronated foot will have the more forwardly rotated innominate bone. And will be the side with the functionally short leg.


The most common treatment for discrepancies in leg length is the use of a simple heel lift, which can be placed within the shoe. In cases where the length discrepancy is moderate, an external build up to the shoe is usually more comfortable. In severe cases, surgery can be used to make the longer leg shorter (or impede its growth), and/or make the shorter leg longer via limb lengthening.

Measurement challenges

Although prone "functional leg length" is a widely used chiropractic tool in their Activator technique, it is not a recognized anthropometric technique, since legs are usually of unequal length, and measurements in the prone position are not entirely valid estimates of standing X-ray differences. [5] Measurements in the standing position are far more reliable. [6] Another confounding factor is that simply moving the two legs held together and leaning them imperceptibly to one side or the other pr

    oduces different results. [7]

    Clinical measurement of leg length conventionally uses the distance from the anterior superior iliac spine to the medial malleolus. [8] Projectional radiographic measurements of leg length have two main variants: [9]

    On X-rays, the length of the lower limb can be measured from the proximal end of femoral head to the center of the plafond of the distal tibia. [10]

    Related Research Articles

    Human leg lower extremity or limb of the human body (foot, lower leg, thigh and hip)

    The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh and even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle, also known as the crus. Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person's mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males.

    Femur most proximal bone of the leg for tetrapode vertebrates, longest bone for humans

    The femur, or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates and of the human thigh. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the tibia and kneecap forming the knee joint. By most measures the femur is the strongest bone in the body. The femur is also the longest bone in the human body.

    Knee region around the kneecap

    In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.

    Tibia larger of the two bones of the leg below the knee for vertebrates

    The tibia, also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates, and it connects the knee with the ankle bones. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane or centre-line. The tibia is connected to the fibula by the interosseous membrane of the leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute tibia. It is the second largest bone in the human body next to the femur. The leg bones are the strongest long bones as they support the rest of the body.

    Ankle Region where the foot and the leg meet

    The ankle, or the talocrural region, is the region where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" can refer broadly to the region or specifically to the talocrural joint.

    An osteotomy is a surgical operation whereby a bone is cut to shorten or lengthen it or to change its alignment. It is sometimes performed to correct a hallux valgus, or to straighten a bone that has healed crookedly following a fracture. It is also used to correct a coxa vara, genu valgum, and genu varum. The operation is done under a general anaesthetic.

    Coxa vara Hip deformity in which the femoral neck leans forward resulting in a decrease in the angle between femoral neck and its shaft. It may be congenital often syndromic, acquired, or developmental.

    Coxa vara is a deformity of the hip, whereby the angle between the head and the shaft of the femur is reduced to less than 120 degrees. This results in the leg being shortened and the development of a limp. It may be congenital and is commonly caused by injury, such as a fracture. It can also occur when the bone tissue in the neck of the femur is softer than normal, causing it to bend under the weight of the body. This may either be congenital or the result of a bone disorder. The most common cause of coxa vara is either congenital or developmental. Other common causes include metabolic bone diseases, post-Perthes deformity, osteomyelitis, and post traumatic. Shepherd's Crook deformity is a severe form of coxa vara where the proximal femur is severely deformed with a reduction in the neck shaft angle beyond 90 degrees. It is most commonly a sequela of osteogenesis imperfecta, Pagets disease, osteomyelitis, tumour and tumour-like conditions.

    Posterior cruciate ligament One of four major ligaments of the knee

    The posterior cruciate ligament is one of the four major ligaments of the knee. It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.

    Anterior cruciate ligament type of cruciate ligament in the human knee

    The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments in the human knee. The 2 ligaments are also called cruciform ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint, based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an “X”. It is composed of strong fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 degrees and 90 degrees of knee flexion. The ACL is the most injured ligament of the four located in the knee.

    Genu varum O-knees

    Genu varum , is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward (medially) in relation to the thigh's axis, giving the limb overall the appearance of an archer's bow. Usually medial angulation of both lower limb bones is involved.

    Popliteal artery

    The popliteal artery is a deeply placed continuation of the femoral artery opening in the distal portion of the adductor magnus muscle. It courses through the popliteal fossa and ends at the lower border of the popliteus muscle, where it branches into the anterior and posterior tibial arteries.

    Shin splints injury or pain in the lower tibia

    A shin splint is pain along the inside edge of the shinbone (tibia) due to inflammation of tissue in the area. Generally this is between the middle of the lower leg to the ankle. The pain may be dull or sharp and is generally brought on by exercise. It generally resolves during periods of rest. Complications may include stress fractures.

    Tarsus (skeleton) bones of the foot

    The tarsus is a cluster of seven articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. It is made up of the midfoot and hindfoot.

    Hip anatomical region

    In vertebrate anatomy, hip refers to either an anatomical region or a joint.

    Stifle joint

    The stifle joint is a complex joint in the hind limbs of quadruped mammals such as the sheep, horse or dog. It is the equivalent of the human knee and is often the largest synovial joint in the animal's body. The stifle joint joins three bones: the femur, patella, and tibia. The joint consists of three smaller ones: the femoropatellar joint, medial femorotibial joint, and lateral femorotibial joint.

    Patellar network Network of blood vessels around the knee

    The patellar network is an intricate network of blood vessels around and above the patella, and on the contiguous ends of the femur and tibia, forming a superficial and a deep plexus.

    Pigeon toe, also known as in-toeing, is a condition which causes the toes to point inward when walking. It is most common in infants and children under two years of age and, when not the result of simple muscle weakness, normally arises from underlying conditions, such as a twisted shin bone or an excessive anteversion resulting in the twisting of the thigh bone when the front part of a person's foot is turned in.

    Tibial plateau fracture

    A tibial plateau fracture is a break of the upper part of the tibia (shinbone) that involves the knee joint. Symptoms include pain, swelling, and a decreased ability to move the knee. People are generally unable to walk. Complication may include injury to the artery or nerve, arthritis, and compartment syndrome.

    Medial knee injuries

    Medial knee injuries are the most common type of knee injury. The medial ligament complex of the knee is composed of the superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL), and the posterior oblique ligament (POL). These ligaments have also been called the medial collateral ligament (MCL), tibial collateral ligament, mid-third capsular ligament, and oblique fibers of the sMCL, respectively. This complex is the major stabilizer of the medial knee. Injuries to the medial side of the knee are most commonly isolated to these ligaments. A thorough understanding of the anatomy and function of the medial knee structures, along with a detailed history and physical exam, are imperative to diagnosing and treating these injuries.

    Bone malrotation refers to the situation that results when a bone heals out of rotational alignment from another bone, or part of bone. It often occurs as the result of a surgical complication after a fracture where intramedullary nailing (IMN) occurs, especially in the femur and tibial bones, but can also occur genetically at birth. The severity of this complication is often neglected due to its complexity to detect and treat, yet if left untreated, bone malrotation can significantly impact regular bodily functioning, and even lead to severe arthritis. Detection throughout history has become more advanced and accurate, ranging from clinical assessment to ultrasounds to CT scans. Treatment can include an osteotomy, a major surgical procedure where bones are cut and realigned correctly, or compensatory methods, where individuals learn to externally or internally rotate their limb to compensate for the rotation. Further research is currently being examined in this area to reduce occurrences of malrotation, including detailed computer navigation to improve visual accuracy during surgery.


    1. Gurney, Burke (2002-04-01). "Leg length discrepancy". Gait & Posture. 15 (2): 195–206. doi:10.1016/S0966-6362(01)00148-5. ISSN   0966-6362. LLD is a relatively common problem found in as many as 40 [1] to 70% [2] of the population. In a retrospective study, it was found that LLD of greater than 20 mm affects at least one in every 1000 people [3].
    2. Knutson G. A. (2005). "Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part II, the functional or unloaded leg-length asymmetry". Chiropractic & Osteopathy. 13 (12): 12. doi:10.1186/1746-1340-13-12. PMC   1198238 . PMID   16080787.
    3. 1 2 3 "Leg Length Discrepancy (Pediatric)". Columbia University . Retrieved 2019-02-14.
    4. 1 2 Sabharwal, Sanjeev; Kumar, Ajay (2008). "Methods for Assessing Leg Length Discrepancy". Clinical Orthopaedics and Related Research. 466 (12): 2910–2922. doi:10.1007/s11999-008-0524-9. ISSN   0009-921X. PMC   2628227 . PMID   18836788.
    5. D W Rhodes, E R Mansfield, P A Bishop, J F Smith. The validity of the prone leg check as an estimate of standing leg length inequality measured by X-ray. J Manipulative Physiol Ther.; 18 (6):343-6
    6. Hanada E, Kirby RL, Mitchell M, Swuste JM (Jul 2001). "Measuring leg-length discrepancy by the "iliac crest palpation and book correction" method: reliability and validity". Arch Phys Med Rehabil. 82 (7): 938–42. doi:10.1053/apmr.2001.22622. PMID   11441382.
    7. "Adjusting the Joints, on season 12, episode 10". Scientific American Frontiers . Chedd-Angier Production Company. 2001–2002. PBS. Archived from the original on 2006.. Video discusses Activator technique and leg length
    8. Page 305 in: M. Lynn Palmer, Marcia E. Epler, Marcia F. Epler (1998). Fundamentals of Musculoskeletal Assessment Techniques. Lippincott Williams & Wilkins. ISBN   9780781710077.CS1 maint: multiple names: authors list (link)
    9. Page 269 in: Dror Paley (2002). Principles of Deformity Correction, Volume 1. Springer Science & Business Media. ISBN   9783540416654.
    10. Sabharwal, Sanjeev; Zhao, Caixia; McKeon, John; Melaghari, Todd; Blacksin, Marcia; Wenekor, Cornelia (2007). "Reliability Analysis for Radiographic Measurement of Limb Length Discrepancy". Journal of Pediatric Orthopaedics. 27 (1): 46–50. doi:10.1097/01.bpo.0000242444.26929.9f. ISSN   0271-6798.

    Rothbart BA 2006. Relationship of Functional Leg-Length Discrepancy to Abnormal Pronation. Journal American Podiatric Medical Association;96(6):499-507