In the normal knee, loads that are 2-4 times body weight are imposed on the tibiofemoral joint. 60% of the load passes through the medial compartment. In a uni-compartmental OA, the altered limb alignment causes the load to be distributed more on the affected compartment, which may accelerate degenerative process and cause pain; Osteotomy redistributes the loads to the uninvolved compartment.
Any person below 60yrs of age having unicompartmental (medial or latertal compartment) osteoarthritis of the knee, is well suited for this procedure.
» Pre-requisites to get an HTO done :
- Physiological age below 60yrs.
- Physically active in a demanding proffesion eg: athelete, gardener (need to kneel).
- Less than 15 degrees of fixed varus or 12 degrees of fixed valgus deformity.
- Patient should have minimum of 90 degree of flexion.
» Results :
The success rates at 10yrs following osteotomy are produced when there have been an overcorrection of the varus deformity by 3 to 10 degrees. Progressive osteoarthritis seems to be the reason for the deterioration of functional outcomes.
» Factors associated with late failures of high tibial osteotomy :
Older age at the time of the surgery
* Less constitutional preopera-tive tibial varus (<5°)
* Advanced femorotibial osteoarthritis of the medial compartment with more than 50% reduction in the jointspace - severe limitation of motion before surgery.