Introduction

Patient demand for a less invasive surgical approach reducing the trauma induced to the joint has resulted in the development of Minimally Invasive Surgery (MIS). Although the length of the surgical incision is appealing to patients, the changes are not purely cosmetic. The surgery should not violate the extensor mechanism in any way. Incisions into the quadriceps tendon or into the vastus medialis muscle make the approach less difficult but this violation will slow the recovery and affect the ROM of the knee. In Asian knees, authors found the variation of VMO, which is essential in early functional recovery in TKA patient, is so much, so new clinical test for MIS QS should be needed to show location relationship between the upper pole of the patella and the insertion of VMO itself to avoid unnecessary injury of VMO during TKA.