Your knee consists of two halves each designed to carry more or less equal loads. In a perfectly aligned lower limb, a straight line running through the middle of the hip to the middle of the ankle will pass through the middle of the knee. This is called the weight-bearing line of the leg. If a person has bow legs the weight bearing line will not run through the middle of the knee, but through the inside half. This results in an excessive load on that part of the knee (a so-called varus knee). With time this will result in abnormal wear of this part of the joint. This is similar to the wear of a car tyre when the alignment of the wheels is incorrect.
One of the solutions to this localized wear in the joint is to realign the leg with a procedure known as an osteotomy. The principal of an osteotomy is to realign the lower limb so that the weight-bearing line runs through the better halve of the knee.
The exact alignment of the lower limb is measured on a special long X-ray where the hips, knees and ankles can be seen on one view. From these X-rays we can measure the degree of malalignment and plan how much we should realign the leg. The goal is to move the weight-bearing from the damaged to the relatively normal part of the joint. The realignment is performed on the tibia just below the knee.
- Surgery for VARUS KNEE : High tibial osteotomy (HTO)