Limb Reconstruction
Dr Uglow is an expert surgeon in limb reconstruction techniques and established the limb reconstruction service at Southampton.
There are many reasons for a difference in length of the legs to occur. Many people have a minor difference and if this is less than 1 cm it is very unusual for it to be a problem. If minor symptoms occur on the leg or back then this can be adjusted by adding a small lift to the shoe.
As the difference increases it will inevitably cause problems and will need treatment. Large differences are caused by many congenital and developmental conditions. The sequelae of infection and trauma can also cause a difference in leg length or an angular deformity. Sometimes a change in angle of the leg can be more troublesome than a pure length difference.
The following is an outline of the treatments available:
Leg Length Correction
This image shows an X-ray of a leg length deformity prior to correction.
The equalisation of differences in length of the legs can be achieved by three ways:
stopping the growth of the long leg
shortening of the long leg
lengthening of the short leg
Limb length deformity
Epiphyseodesis
This is the term to describe stopping a growth plate (the growing part of a bone). When one leg is shorter than the other this operation will be used to stop the growth of the longer leg. The timing is crucial and is calculated to allow the shorter leg to ‘catch up’ by the time that growth stops. This method can be used to correct differences up to 5cm.
Acute Shortening
This is the least used method as an epiphyseodesis is more minor and usually very successful. If there is not enough growth left to achieve the desired correction, the long leg can be shortened by removing a segment of bone. This is acceptable for the femur but rarely the tibia and can work for 2-3 cm differences but not more. The bone needs to be fixed, usually with an intramedullary nail but a plate and screws can be used.
Precice Intramedullary Lengthening Nails
The latest technology has revolutionised leg lengthening and can be used for differences up to 8 cm but usually 5cm is achieved at any one episode. Multiple episodes may be required through childhood in severe cases. These nails have a motor inside them which is driven by an external electromagnet device which is placed against the leg for several minutes 3 or 4 times each day until the length required has been achieved. This is now the gold standard device for use in bone lengthening.
A femur being lengthened from inside using the new generation Precice IM nail
External Fixator Frame Correction
This has been the mainstay method for bone lengthening using special external fixator frames. The bone is divided and then by turning components on the frame the length and any deformity is corrected over a period of several weeks. This treatment is highly specialised and time consuming but excellent results can be achieved. The main complications relate to pin infections which do not occur with the new nails. Frames will still have a role in younger children who are too small to be fitted with a lengthening nail.
A femur undergoing lengthening using an external fixator over an intramedullary nail.
A circular external fixator being used to correct deformities at two places in a tibia, simultaneously.
Bone Deformity Correction
Guided growth
A guided growth plate is used to control angular growth of long bones. A metal plate and 2 screws are applied across the growth plate of the affected bone and with time due to growth the angle will change and straighten the deformity. The plate can then be removed and the bone will continue to grow straight.
Acute correction
Surgery is used to divide the bone at the site of a deformity and correct the angulation in one step. Metal such as wires, pins or plates are used to stabilise the bone until healing occurs. Plaster casts may be required as well.
External frame correction
For more complex deformities the correction is achieved gradually using special external fixator frames and can be used for lengthening at the same time as described above.