Extensile medial approach to the femur.

A proposed extensile medial approach to the medial surface of the shaft of the femur was studied on 30 cadaver thighs. The incision is made along a line extending from the mid inguinal point to a point one-third the distance from the adductor tubercle to the medial side of the patella. After mobilizing the sartorius muscle posteromedially, the medial femur is exposed by a three-step technique. Step I involves bluntly defining the internervous plane distally between the vastus medialis muscle and the adductor magnus tendon until limited proximally by the distal end of the vastoadductor membrane at an average of 9 cm from the adductor tubercle. In step II blunt dissection between the vastus medialis and the adductor longus muscles is carried from proximal to distal until limited by the proximal end of the vastoadductor membrane. Now the well-defined vastoadductor membrane area ("danger zone") measuring 6 cm in length on average is safely dealt with (step III) and the medial femur is exposed. Distal extension can be made to expose the knee joint. The approach can be extended proximally to the lesser trochanter between the vastus medialis and both the adductor brevis and pectineus muscles. Anatomic measurements in relation to the adductor tubercle and cross-sections of the thigh were made to better describe anatomic constants and variables in this rather unfamiliar medial thigh area.