What will it look like?
One concern of many patients is what their frame will look like. They often want to know how wide it will be, how long it will be, and if it is going to cross any joints.
Although every circular frame is constructed slightly differently, there are patterns that we use, depending on the effect required. Some of these patterns are shown in the photographs on this page.
The appearance will be different depending on whether the frame has been applied for a broken bone, or to correct a deformity. Often, correcting a deformity requires a frame with pistons connecting two of the rings together. The pistons can be adjusted, and this gradually alters the shape of a bone.
Non Union Frame
This frame has been applied to deal with a non-union. This describes a situation where there has been a fracture of a bone, but it has failed to heal. There is still movement between the two ends of the fracture. This means that there is pain and the bone may be unstable, so that the leg cannot bear weight.
The frame extends above and below the region that the bone has failed to heal. Usually, there are two rings above and two rings below the fracture non-union.
The rings are joined together by rods. The rings are large enough to allow for any calf swelling that might occur. This is a common problem with any frame. The rings are thinner and slightly lighter than those used for changing the alignment of a limb.
High Tibial Osteotomy Frame
This type of frame is used for the correction of a deformity in the upper shin bone. Typically, there are six pistons mounted between two of the rings. The rings are slightly thicker, and have special connections to allow the pistons to be attached.
There may be one or two rings at the top of the shin bone. There will be two rings in the bottom half of the shin bone. A break in the bone is made in order to allow the overall shape of the leg to be changed by gradually moving the bones.
There is enough room around the leg for swelling that is associated with the operation and the break in the bone. This swelling commonly lasts for several months after the frame has been finally removed.
The pistons are gradually altered in length at home by the patient. The pistons have a scale that allows the patient to be sure that the length each day is correct to slowly change the shape of the leg.
Ankle Fusion Frame
This frame is designed to help stiffen the ankle joint permanently. If the ankle joint is damaged in some way, then it may be painful and stiffening it will help to relieve pain.
There are ways to stiffen the ankle joint without an external fixator. However, if there has been an infection, or there is a complicated deformity that needs to be corrected, an external fixator may be required.
The frame crosses the ankle joint. There is one ring around the foot. There are two rings around the shin. These rings are connected with metal rods. The rings are compressed together, and this compressed the bones together at the ankle level. Over a few months, the bones on either side of the ankle joint will fuse together to become one bone.
Low Tibial Osteotomy Frame
This frame is designed to alter the shape of the shin bone just above the ankle. The shin bone has to be broken in order to allow the shape of the bone to be changed. There are pistons between two of the rings, and these allow the shape to be gradually changed.
There are two rings above the break in the bone. As there is not much shin bone below the artificial fracture, the ankle may not be stable. Therefore, a further ring has been applied around the foot. This ensures that the alteration in shape occurs at the site of the break, and not through the ankle joint itself.
The ring on the foot can be removed once the overall shape has been corrected. The other three rings would need to remain until the bone has completely healed up.
Tibial Trauma Frame
This is a common shape of circular frame used for treating fractures. There are generally two rings above the fracture and two rings below the fracture. The rings are joined together by metal rods. These can be adjusted for length if required, but cannot change the shape of the leg otherwise.
The rings leave enough room for swelling of the calf, which is common after a fracture. The swelling may take a year to completely recede.
If the bone is not aligned after the operation, or any adjustments need to be made to the shape of the leg, then the metal rods joining the rings together can be replaced by pistons. These pistons can allow the rings to be moved over each other, and this moves the bones connnected to them. This is not often required, but there is always this facility available, if the shape of the bone is not symmetrical with the bone that has not been injured.
Low Tibial Fracture
If there is a fracture of the shin bone that is very low in the shin, or the fracture extends into the ankle joint and is more complicated, then this type of frame is used.
There is one ring at the level of the ankle joint. There are two rings completely above the level of the fracture. There is a ring around the foot, connected to the ring at the level of the ankle joint.
Often the ring around the foot is removed after six weeks, when the fracture has started to heal. The other three rings will remain in place for at least another six weeks. The ring around the foot means that the patient can walk immediately after surgery without fear of the fracture fragments moving at the ankle joint.
Foot Deformity Frame
This type of frame is used for complicated foot deformities. The foot rings have to be connected to the shin bone to make them stable.
The rings around the foot are connected with a set of pistons. These pistons can be used to gradually rotate the foot or change the overall shape. This is used in conjunction with carefully placed breaks in bones, that allow the bones to move and heal up in the new position.
Patients who have this type of frame have usually had lots of previous operations to correct the position of their foot. It cannot give patients a normal ankle or foot, but it can allow the shape to be altered to make the foot adopt a normal position and for normal shoes to be worn.
Tibial Plateau Fracture Frame
If there is a fracture at the top of the shin bone, and this involves the knee joint, then the frame may span the knee joint and connect to the thigh bone.
Typically there will be three rings over the shin bone, one of these at the level of the knee joint. The other ring is above this, and connects to the thigh bone.
The ring on the thigh bone may be removed after six weeks, to allow the knee to move, as it could get very stiff otherwise. It allows the patient to put their full weight on the leg without fear that the fracture position could be changed by the force of a patients weight. Effectively, the frame by-passes the knee fracture and transmits the weight from the bone above the fracture to the bone below the fracture.