Lengthening Nails

For different reasons, lengthening of a long bone such as the femur (thigh bone) or tibia (shin bone) can become necessary. Shortening of a bone is often the result of a fracture but can be congenital (developing since birth) or idiopathic (present for an unknown reason). Additionally, various metabolic and syndromic disorders present with limb-length discrepancy or severe limb shortening.

Limb lengthening using an internal lengthening nail (Precice; NuVasive, Inc., San Diego, California, USA) entails certain steps. During surgery, the nail is placed within the cavity of the bone and the bone is cut. The nail is fixed to the bone with two screws at the upper end and two screws at the lower end. Approximately 1 week after surgery, the nail is lengthened using magnetic external remote control and the bone is distracted approximately 1 mm per day. This is done at home in four sessions of 0.25 mm of distraction per session. Because the process is so slow, the patient does not usually experience pain. Physical therapy is essential to keep the joints fully flexible and strong. When the desired length is achieved, lengthening is stopped.

The duration of treatment depends on the amount of lengthening necessary. After lengthening approximately 1 mm per day, it takes double to triple that time for the bone to heal.

Precice Verlängerunsnagel Beinverlängerung 1
Phase 1: Insertion of the lengthening nail and osteotomy (bone cut) (red circle) (image: OSS)
Precice Verlängerunsnagel Beinverlängerung 2
Phase 2: Gradual distraction and new bone formation (image: OSS)
Precice Verlängerunsnagel Beinverlängerung 3
Phase 3: New bone consolidates and remodels (image: OSS)
Precice Verlängerunsnagel Beinverlängerung 4
Phase 4: Bone has completely healed, and nail has been removed (image: OSS)

Touch-down partial weight-bearing is possible during the distraction (lengthening) phase of treatment. The newest generation of lengthening nails is especially stable and allows for early full weight-bearing without crutches. The nail is removed approximately 1 year after the end of treatment.

Oberschenkel Bein verkürzt Orthopädie
Shortened femur (thigh bone) before treatment
Verlängerungsmarknagel Precice Oberschenkel 1
Femur with Precice lengthening nail at end of distraction
Verlängerungsmarknagel Precice Oberschenkel 1
Bone has fully healed around nail and has remodeled; nail can be removed

Lengthening nails allow gentle and comfortable correction of limb-length discrepancy and limb shortening. Simultaneous correction of a malalignment (bowlegs, knock-knees) is possible using advanced fixator-assisted techniques.

The use of lengthening nails in children is limited by the presence of the growth plate. In the femur (thigh bone), lengthening with an intramedullary (IM) nail is possible through an approach at the hip from the age of 8 to 10 years. Lengthening of the femur using an approach through the knee and lengthening of the tibia (shin bone) can be done only when the growth plates are closed or nearly closed. The growth plates of the femur and tibia usually close at the age of 14 years in girls and 16 years in boys. If a growth plate has been injured and closed by a fracture or infection, nail lengthening is possible.

In cases of mild shortening, it is an option to wait until the growth plates are closed and then perform IM nail lengthening. In cases of more severe shortening and limb-length discrepancy for which waiting is not a good option, lengthening can be performed using external fixation.

Because of my extensive experience with lengthening nails and the high number of cases I treat every year, I can safely and expertly treat even the most complex cases, including congenital and metabolic shortening with and without additional deformities.