LLD can be due to many causes. These are divided into three groups: congenital (from birth), developmental (from a childhood disease or injury that slows or damages the growth plates), and posttraumatic (from a fracture that leads to shortening of the bone ends). There are three ways to equalize the LLD: use a shoe lift, shorten the long leg, lengthen the short leg. Most patients do not like wearing a lift greater than 2 cm (3/4 in). For discrepancies greater than 2 cm but less than 5 cm (2 in), shortening of the long leg can be considered, especially for tall persons. For growing children, this can be easily accomplished with a small, minimally invasive, uncomplicated procedure called epiphysiodesis.
This means surgically closing one or more of the growth plates. Because children have one growth plate at each end of the femur and tibia and fibula, this does not stop all the growth of the leg. It simply slows down the growth of the long leg by a predictable amount, allowing the short leg to catch up. If this procedure is performed at too early or too late an age, too much or too little correction, respectively, will result. Therefore, it is essential to calculate the age that is best for epiphysiodesis as accurately as possible.
A recent publication by Drs. Paley and Herzenberg describes a new more accurate method for calculating this prediction: the multiplier method. In adults, the growth plates are already closed, so epiphysiodesis is not an option. To shorten the lower limb in an adult, a segment of bone has to be surgically removed. This is most often done in the femur (thigh bone), and the bone is fixed with an intramedullary nail. The biggest advantage of this method is that it immediately equalizes the LLD in cases in which the discrepancy is less than 5 cm. The primary disadvantage of both epiphysiodesis and shortening is that the patient's height is reduced by the amount of shortening. Because we do not recommend shortening by more than 5 cm (2 in), the height loss is never greater than 5 cm (2 in). For patients who do not want to undergo shortening or epiphysiodesis for discrepancies less than 5 cm and in cases in which the discrepancy is greater than 5 cm, limb lengthening is the procedure of choice to achieve leg length equalization. Epiphysiodesis and shortening can be combined with lengthening to decrease the need for one additional lengthening or to decrease the amount of one of the lengthenings. Patients must keep in mind that epiphysiodesis is a much more minor procedure than lengthening.
Cases of congenital LLD often present the most challenging and difficult lengthenings to perform and should be treated only by experts in the field who have significant experience with lengthening of developmental and posttraumatic LLD. Not only is the amount of LLD frequently large, it progressively and proportionally increases with time. Currently, there is no known way to accelerate the growth rate of the short leg. In addition to problems concerning the bone, the soft tissues are unusually thickened and contracted, which makes them resist stretching and growing from the lengthening process. The hip, knee, and/or ankle may also be underdeveloped, deformed, and/or unstable. All of these factors must be considered and addressed to avoid irreversible damage to joints, nerves, muscles, etc.
At the ICLL, we have perhaps the world's largest experience and most successful results in reconstruction and lengthening of the congenitally short femur and tibia. This is called lengthening reconstruction surgery (LRS). Congenital shortening of the femur is often referred to as proximal femoral focal deficiency (PFFD). A better name for this is congenital femoral deficiency (CFD). Congenital shortening of the tibia is often associated with partial or complete absence of the smaller adjacent fibula bone. This is called fibular hemimelia. Tibial hemimelia is a congenital shortening of the leg segment with which part of or all the tibia is missing. Other types of congenital shortening that affect the tibia and femur are called hemihypertrophy and hemiatrophy. Patients with these conditions usually have a milder amount of shortening. Posteromedial bowing of the tibia is another type of congenital shortening of the tibia associated with characteristic tibial and foot deformities. Each of these types of congenital shortening requires a different approach to lengthening reconstruction surgery.
At the ICLL, we have treated all the above mentioned types of congenital LLD. We start by accurately predicting the amount of LLD that will be present when the child reaches the end of growth (skeletal maturity). We identify all the deformities and joint instabilities present and, based on this information, we organize a treatment strategy for reconstructing the limb, which may include reconstruction of the hip, knee, and/or ankle and foot as the first step. Lengthening reconstruction surgery may involve one or more operations. Most cases of congenital LLD can be treated with lengthening and reconstruction. In many cases, we prefer to start the lengthening and reconstruction surgery process before the patient reaches the age of 4 years, often by the age of 2 years.
Alternative methods of treatment are operations designed to modify or amputate the limb so that it can be more easily fitted into a prosthesis, whereby the prosthesis can be lengthened to equalize the LLD as the child grows. We call this prosthetic reconstruction surgery (PRS), and it includes operations such as Syme amputation and Van Ness rotationplasty. Although this may be the best treatment option in the most severely deficient cases in which one or more joints are missing, in our opinion, it is not the best option for the majority of patients. Our lengthening reconstruction surgery results for both the femur and the tibia, and even for very large LLD, are excellent and provide excellent function after treatment with preservation and often improvement in joint function.
This includes LLD caused by conditions such as growth plate injury and growth arrest, Ollier's disease, multiple osteochondromas, polio, infection, radiation, cerebral palsy, spina bifida, clubfoot, etc. This LLD group often has associated deformities. Most cases can be treated by one or two lengthenings. If deformity is present, it can be corrected at the same time as the lengthening. In some special cases, such as neonatal sepsis of the hip with which the hip joint is destroyed by infection in the first year of life, we not only lengthen the leg but also reconstruct the hip with a special technique called pelvic support osteotomy. This allows us to recreate nearly normal hip function in an otherwise absent or destroyed hip joint.
Posttraumatic LLD (Malunion)
This is the LLD that remains after a fracture heals in a shortened position. Most of these cases occur in adults, and most can be corrected with only one lengthening. Associated deformity can also be corrected at the same time. Many of these patients can be treated by the lengthening over nail or fully implantable nail method.