Tibial realignment by oblique wedge osteotomy. A new method based on accurate measurement.

A new method for calculating the angle of correction in upper tibial osteotomies is described. The wedge differs from the current techniques in being oblique. The apex is sited on the medial cortex to lie level with the tibial tubercle. The wedge is coned downwards at an angle of 45 degrees, based laterally. This keeps clear of the bifurcation of the popliteal artery, whilst still being contained in the cancellous zone. The method of accurately determining the angle of the wedge and the width of the base using logarithmic calculations is outlined. Being oblique, on removal of the wedge, the cut surfaces match as they meet. Two screws are inserted to lie at right angles to the plane of osteotomy. A long leg plaster cast is worn for six weeks. Thereafter a cast brace is substituted to permit knee and ankle movements. The osteotomy unites rapidly across the large oblique contact surfaces. Pain relief has been substantial and lasting in every patient. The range of flexion returned to the level elicited under anaesthesia immediately prior to the operation.