Limb lengthening is a two-stage surgical procedure to correct the problems associated with having legs of different lengths. Having one leg shorter than another may occur as the result of an accident or due to a medical condition and it can cause pain and mobility problems. The limb lengthening procedure encourages the growth of new bone, causing the limb to lengthen. It is often carried out at the same time as surgery to correct lower limb deformities.
Limb lengthening is a surgical procedure carried out under general anaesthetic, followed by a period of consolidation, strengthening and healing. During surgery, the bone of the affected limb is cut and separated using either an internal or an external fixator. Internal fixators contain a telescopic rod that is implanted inside the centre of the bone. Over time the rod is gradually lengthened using an external remote control until the required length is reached. An external fixator is a type of frame that is used to support the separated bones. Over a period of time it is gradually adjusted to pull the bones and tissues apart, resulting in new bone growth. Bones typically grow at around a millimetre a day.
There are two phases to the limb lengthening process:
- Distraction – this is when the bone and soft tissue are cut and slowly pulled apart to encourage new growth.
- Consolidation – this is when the correct bone length has been achieved. The new bone is given time to harden and the tissues time to heal. As the bone hardens, you will slowly be able to use the limb more.
Prior to surgery you will undergo screening to check for levels of Vitamin D and to rule out infection and other problems that may affect the outcome of surgery.
You might need this type of surgery if you have had an accident or injury that has resulted in shortening of the limb. Limb lengthening surgery may be offered to children who have conditions such as:
- Hemihypertrophy which causes the sides of the body to grow at different rates.
- Neurofibromatosis which is a rare condition that causes overgrowth in one leg and sometimes also curvature of the spine and skin conditions.
- Overgrowth after a fracture.
You will normally remain in hospital for a few days after the procedure. The day after surgery you will be seen by a physiotherapist who will develop a programme of daily exercises that are a vital part of the procedure. New bone will normally begin growing a few days after surgery. This is called the latency period. You will be shown how to lengthen the bone each day using the fixator.
Once the bone has reached the required length, you will be able to stop using the fixator to adjust bone length but it will remain in situ while the bones harden. For each additional 1cm of bone that you have grown, the fixator will need to remain in place for 60 days. So, if you have gained an additional 4cm of leg length the fixator will stay in place for eight months. Throughout this period you will undergo regular X-rays to check that the new bone is healing correctly before the fixator is removed.
Limb lengthening surgery produces good results providing the correct procedures are followed during the consolidation process. If the gap between the bone is increased too fast the new bone may not grow sufficiently which could result in long-term nerve and tissue damage. If the gap is increased too slowly the bones may join up too quickly, preventing further limb lengthening. It is particularly important to avoid smoking or taking anti-inflammatories as these can slow the healing process.