Knee deformities are common reason for a patient to see the doctor. This may be for reason of cosmesis, or pain as a result of maltraking on a crooked knee. Mostly these result from abnormality in growth of the knee, where unequal growth occurs at inner and outer side of the knee. This unequal growth results in either bow legs (genu varum) or knock knees (genu valgum). Such growth related deformities are usually on both the sides. Often, only one knee may develop a problem which affects the growth of the bones around the knee, and produce varus or valgus deformity. Mismanaged fractures around the knee also result in deformity of the knee. In early stages deformities are merely cosmetic problems and give rise to limp. In later stages, these may result in wearing away of the knee, called osteoarthritis. Most deformities can be successfully treated by surgical correction. This involves making a cut in the bone and then re-aligning the bones in correct position till they heal (osteotomy). Fixation of the bones after cutting, is also required in most cases.
Genu varum (bow legs): These are corrective by surgery. The bone just below the knee (tibia) is cut , re-aligned and fixed with a special plate called Tomofix. This permits early mobility and predictable correction of the deformity. Both legs can be operated at the same time. The operation is performed under control of a special video x-ray machine (image intensifier) in the OT, by which one can see the position of the bones while performing the surgery. With this, the surgeon is sure about the correction achieved, right in the operation theatre.
Genu valgum (knock knees): The principle of correction remains the same, i.e, corrective osteotomy (cutting the bone) and realigning. Conventionally, this involves open surgery via a 10 cm cut, and fixation of the cut bones with steel plates and screws. The plates and screws need subsequent removal. Though the deformity can be very well corrected, the surgery leaves a scar. Since this deformity commonly occurs in adolescent girls, and is corrected mostly for cosmetic reason, the resultant scar becomes a cosmetic issue.
There is a special technique of corrective surgery for knock knees which is practiced at our centre, in which corrective surgery is done without open surgery. This is called closed osteotomy, and is performed thorugh a 1 cm cut. The bone is weakened at the desired site by internally cracking it, and brought in corrected position by plastic deformation. Once the desired correction is achieved, plaster cast is applied for 4 weeks. In this technique, there is no steel implant inside the body, and there is a barely visible 1 cm scar on the leg.
Other deformities of the knee are the knee bent in front (flexion deformity) or to the back (recurvatum deformity). These may be treated with physiotherapy in the initial phase, but need corrective surgery later. The surgery may involve cutting the tight tissues or cutting the bone.