LLD Conditions FAQs
Although there are differing opinions on how to measure leg length, the standard workup for limb length discrepancy is a thorough physical examination, including watching the patient walk and run. Additionally, the surgeon performs a three-joint standing x-ray analysis or an x-ray scanogram to determine the actual length of the legs.
During the x-ray imaging, a long ruler is put in the field of view so an accurate measurement of each leg bone can be taken to determine how big the discrepancy is (or will be if a child is still growing), and this helps determine the best treatment plan.
While a small limb length discrepancy may not cause problems, a significant difference (more than 2 cm) can cause a noticeable limp and will often require treatment. Non-surgical treatment options include the “wait-and-see” approach for children who are still growing, and the shoe lift, which manages the symptoms but does not correct the discrepancy permanently.
There are also surgical methods of treating leg length discrepancy. Each of these techniques produces a permanent correction of the leg lengths. Depending on your condition, you and your surgeon may choose to shorten the long leg or lengthen the short leg.
Surgical treatment options are generally used for larger leg length discrepancies and in cases where the patient wants a permanent solution.
- Bone growth restriction (epiphysiodesis or growth arrest) is often successful when performed at the right time in adolescence, but may cause short stature.
- Bone shortening is more predictable than epiphysiodesis, but has a much longer recovery period.
- Leg lengthening surgery allows patients to achieve their full height potential, but external fixators require continual maintenance. Internal fixators produce comparable results with fewer risks.
Some limb length discrepancies may require special treatment, but you and your surgeon can decide what treatment, if any, is best for you (or your child). Any treatment will be planned with the child’s final height and leg lengths in mind, not the current leg lengths.
Walking, or running, relies on constant shifting from one base of support to the other. Limb length discrepancy, or unequal limb lengths, can increase the amount of energy needed to walk and reduce muscular efficiency, making movement more difficult. Although, there are many people who have a small amount of LLD that do not have any pain or discomfort.
When lower limbs are not the same length, it causes a limp. With a small difference in limb length (less than ¾ inch), a person can hide his/her limp by tilting the pelvis, causing a slight curve of the spine. If the difference between limbs is greater, the limp is worse, which can cause back pain and significant curve of the spine.
Limping causes abnormal pressure on the joints and can lead to painful arthritis of the hip, knee, or ankle, if left untreated. Additionally, unequal limb lengths — of the upper or lower limbs — may cause social problems, especially in children.
Some parents are concerned that a leg length discrepancy may cause or contribute to scoliosis. While someone with a leg length discrepancy can appear to have a curvature of the back, it does not cause permanent spine deformity (scoliosis).
In the standing position, a leg length discrepancy may cause tilting of the pelvis. The spine will try to compensate for this tilt by curving back in the opposite direction. This curvature is usually flexible and goes away in the sitting position. It is possible to have both a leg length discrepancy and scoliosis at the same time but only as two independent diagnoses.
The greater the limb length inequality, and the younger the patient, the more problems can result as the patient grows. Back, hip, and knee problems often occur if the condition is left untreated. The good news is that treatment of LLD often leads to a good outcome, and patients go on to lead healthy, happy lives.
The PRECICE Intramedullary Limb Lengthening (IMLL) System is composed of an implantable intramedullary nail, locking screws, reusable instruments, and a hand-held External Remote Controller (ERC). The PRECICE nail is a sterile single use device that is surgically implanted using the instruments and locking screws. The ERC is used daily after implantation to non-invasively lengthen or shorten the implant to a prescribed length. The PRECICE System is intended for limb lengthening of the femur and tibia. Contraindications include infection or pathologic conditions of bone such as osteopenia which would impair the ability to securely fix the device, metal allergies and sensitivities, patients whose distance from the surface of the treated limb to the intramedullary canal is greater than 51 mm for the 10.7 and 12.5 mm diameter implants or greater than 38 mm for the 8.5 mm diameter implant, patients with an irregular bone diameter that would prevent insertion of the PRECICE nail, patients in which the PRECICE nail would cross joint spaces or open epiphyseal growth plates, patients in which there is an obliterated medullary canal or other conditions that tend to retard healing such as blood supply limitations, peripheral vascular disease or evidence of inadequate vascularity, patients unwilling or incapable of following postoperative care instructions, patients weighing in excess of 114 Kg for the 10.7 and 12.5 mm diameter implants (models A-G, H, J, K, and U) or weighing in excess of 57 Kg for the 8.5 and 10.7 mm diameter implants models (A-G, H, J, K, U, N, M ,P, and Q). The implantable device is only to be used by a trained licensed physician. Please refer to the PRECICE IMLL System instructions for use for complete Important Safety Information. Caution: Federal law restricts this device to sale by or on the order of a physician.