Functional Leg-Length Discrepancy


Every person?s body is unique and will show different symptoms due to a short leg. Athletes are able to distinguish the negative effects of a leg length that is just 3 mm shorter then the other. A whole host of negative effects can occur to the body that can create chronic pain and may necessitate surgical interventions. The effect of a short leg can be seen almost everywhere in the body.Leg Length Discrepancy


A number of causes may lead to leg length discrepancy in children. Differences in leg length frequently follow fractures in the lower extremities in children due to over or under stimulation of the growth plates in the broken leg. Leg length discrepancy may also be caused by a congenital abnormality associated with a condition called hemihypertrophy. Or it may result from neuromuscular diseases such as polio and cerebral palsy. Many times, no cause can be identified. A small leg length discrepancy of a quarter of an inch or less is quite common in the general population and of no clinical significance. Larger leg length discrepancies become more significant. The long-term consequences of a short leg may include knee pain, back pain, and abnormal gait or limp.


The effects of a short leg depend upon the individual and the extent of discrepancy. The most common manifestation if a lateral deviation of the lumbar spine toward the short side with compensatory curves up the spine that can extend into the neck and even impacts the TMJ. Studies have shown that anterior and posterior curve abnormalities also can result.


Leg length discrepancy may be diagnosed during infancy or later in childhood, depending on the cause. Conditions such as hemihypertrophy or hemiatrophy are often diagnosed following standard newborn or infant examinations by a pediatrician, or anatomical asymmetries may be noticed by a child's parents. For young children with hemihypertophy as the cause of their LLD, it is important that they receive an abdominal ultrasound of the kidneys to insure that Wilm's tumor, which can lead to hypertrophy in the leg on the same side, is not present. In older children, LLD is frequently first suspected due to the emergence of a progressive limp, warranting a referral to a pediatric orthopaedic surgeon. The standard workup for LLD is a thorough physical examination, including a series of measurements of the different portions of the lower extremities with the child in various positions, such as sitting and standing. The orthopaedic surgeon will observe the child while walking and performing other simple movements or tasks, such as stepping onto a block. In addition, a number of x-rays of the legs will be taken, so as to make a definitive diagnosis and to assist with identification of the possible etiology (cause) of LLD. Orthopaedic surgeons will compare x-rays of the two legs to the child's age, so as to assess his/her skeletal age and to obtain a baseline for the possibility of excessive growth rate as a cause. A growth chart, which compares leg length to skeletal age, is a simple but essential tool used over time to track the progress of the condition, both before and after treatment. Occasionally, a CT scan or MRI is required to further investigate suspected causes or to get more sophisticated radiological pictures of bone or soft tissue.

Non Surgical Treatment

Internal heel lifts: Putting a simple heel lift inside the shoe or onto a foot orthotic has the advantage of being transferable to many pairs of shoes. It is also aesthetically more pleasing as the lift remains hidden from view. However, there is a limit as to how high the lift can be before affecting shoe fit. Dress shoes will usually only accommodate small lifts (1/8"1/4") before the heel starts to piston out of the shoe. Sneakers and workboots may allow higher lifts, e.g., up to 1/2", before heel slippage problems arise. External heel lifts: If a lift of greater than 1/2" is required, you should consider adding to the outsole of the shoe. In this way, the shoe fit remains good. Although some patients may worry about the cosmetics of the shoe, it does ensure better overall function. Nowadays with the development of synthetic foams and crepes, such lifts do not have to be as heavy as the cork buildups of the past. External buildups are not transferable and they will wear down over time, so the patient will need to be vigilant in having them repaired. On ladies' high-heel shoes, it may be possible to lower one heel and thereby correct the imbalance.

LLL Shoe Insoles

shoe lift inserts

Surgical Treatment

Large leg length inequalities can be treated by staged lengthenings or by simultaneous ipsilateral femoral and tibial lengthenings. Additionally, lengthenings can be combined with appropriately timed epiphysiodesis in an effort to produce leg length equality. Staged lengthenings are often used for congenital deficiencies such as fibular hemimelia, in which 15 cm or more may be needed to produce leg length equality. We typically plan for the final lengthening to be completed by age 13 or 14 years, and allow at least 3 years between lengthenings. Lengthening of both the tibia and femur simultaneously requires aggressive therapy and treatment of soft tissue contractures. Curran et al[57] reported the need for surgical release of soft tissue contractures in 3 of 8 patients treated with simultaneous ipsilateral femoral and tibial lengthenings. Lengthening over an IM nail can be done in an effort to decrease the amount of time the fixator needs to be worn and to prevent angular malalignment. This technique requires that the patient be skeletally mature and it carries a higher risk of osteomyelitis (up to 15%). Additionally, if premature consolidation occurs, a repeat corticotomy is more difficult.