Limb lengthening may be needed if a child has a discrepancy in their leg lengths.

Limb Lengthening

What is limb lengthening?

There are certain conditions that can mean limbs need lengthening. For example, some children have legs of two different lengths and the discrepancy can cause issues such as a limp, pain or even arthritis as an adult. In order to address these problems, limbs can be lengthened slowly over a period of time to reduce the discrepancy. 

Precice Nail surgery


There are a small number of surgeons who can carry out Precice Nail surgery and Mr Crompton is one of these. A precice nail is a device that is placed within the bone during an operation. It is used to grow new bone and change the length of the limb. The nail contains a magnet and a gear system, which can lengthen or shorten the nail. In order to activate it, an external handset is placed on the limb. 

The operation

During the surgery, the nail is inserted into the centre of the bone and secured with screws. The bone is then divided in a specific place. You can expect to see surgical wounds where the nail and screws are inserted and also in the area where the bone has been divided.

The lengthening process

Around 5-7days after the surgery, the lengthening process should begin. Instructions will be given on how to use the handset and you will be supported until you are confident to carry out the adjustment on your child yourself. To do the lengthening, you will need to place the handset in a specific place on the limb – this will be marked for you to ensure you know where to put it. This will also need to be done around three times a day. 

As the handset contains a strong magnet, it is important that before it is activated any metal objects such as watches, phones or credit cards should not be placed near the device. Furthermore, anyone with a heart pacemaker should not be within a close distance.

How does it work?

As bone is slowly pulled apart using the precice nail, new bone starts to form in the gap and soft tissues also get stretched. At the same time, nerves are stretched. This can cause some stiffness in the muscles so it is important to do exercises to prevent this from being permanent. 

Bone is usually lengthed around 1mm per day, but this does vary with each child. The bone needs to harden but after this, the nail can be removed. During the lengthening process, it is not possible to weight bear on the limb and crutches will be used. However, it is important to maintain movement. I work closely with specialist physios to help with this.

During the lengthening process, you will need to bring your child to a clinic regularly to have x-rays to see how the new bone is forming. This will help inform any decisions around adjustments to the precice nail.

Helpful resources

A patient's story


"We as parents have complete confidence in all that you do, and have done for us, and appreciate your commitment to McKenzie. Your attention is both professional, personal and fills us with confidence and it is much appreciated."

McKenzie's Dad

Where we work

We are based at The Royal Alexandra Children’s Hospital in Brighton and also see children at The Portland hospital, London and Spire Gatwick Park Hospital, Horley. We offer a range of clinics, so can see your child at a time that is convenient for you.

Furthermore, you can book an appointment with me through Top Doctors or the Orthopaedic Specialists Clinic.




The Royal Alexandra Children's Hospital

Eastern Road



The Portland Hospital

2nd floor, 215 Great Portland Street



Spire Gatwick Park Hospital

Hookwood, Horley


The Cromwell Hospital

164-178 Cromwell Road