KNEEissues and Clinical Casebook

This case presentation is that of a gentleman who suffered severe bow-leg deformity from a non-union of a tibial plateau fracture. Limb realignment using an external fixator allowed almost total correction of the deformity without requiring open surgery.

The patient is a 66 year old farmer who suffered a tibial plateau fracture (break) into his right knee. The fragments were originally only minimally displaced (see arrows on the left hand X-ray). Two screws were surgically inserted to hold the upper fragments together, but the lower fracture was not fixed (arrow - right hand X-ray). (Click pictures to enlarge)

The gentleman was very busy with his farm, and kept on working. However, gradually the leg bowed until he was really disabled, and unable to get around without crutches.

The ‘good’ leg (his left), in which he had already had a knee replacement for arthritis, was having to take all the strain. The bones were unhealed and the top section had collapsed onto the bottom part (see arrows). The patient was referred for specialist opinion.

The specialist applied a circular external fixator to the upper tibia, initially bridging the knee (not allowing movement in the joint). It was attached to the bone using a combination of percutaneous (through the skin, with no open incisions [cuts]) wires and screws.

The patient went home walking with crutches.

He gradually corrected his deformity by using a 6mm Allen key on a distraction unit on one side of the fixator, to stretch the bone gradually on one side at the rate of 1 mm a day. This allowed the patient to form his own bone very slowly, by a process called ‘callus distraction’, until the mechanical axis was shown to be fully corrected on his X-rays.

The top ring was then removed, which allowed the knee to move and he could take weight on his leg. He continued to carry out his farming activities including driving his tractor on a daily basis.

With the mechanical axis fully corrected, the patient was able to take full weight, and the weight going through the fracture site encouraged full healing of the bone in a good position.

The patient went home walking with crutches. Note that there was absolutely no open surgery involved. The procedure harnesses the body’s own biology to allow healing, with no bone grafting required. This procedure is not excessively painful, and only tiny wounds are made through the skin. No plaster is worn.  The patient sleeps with the device on and participates in the process in making the daily screw adjustments according to the surgeon’s orders.

As it is minimally invasive, this procedure seldom has complications other than pin site infections, which are easily managed.

This type of specialist procedure offers hope for patients with severe deformity and/or non union, not only of the tibial plateau.