Mc Murray’s osteotomy is done for
Mc Murrary's osteotomy is an oblique osteotomy at the intertrochanteric region.
The direction of osteotomy is medially upwards, beginning at the base of the greater trochanter & ending just above the lesser trochanter.
Once osteotomy is made, the distal fragment is displaced medially & is abducted. The position is held by an external support( hip spica) or by internal fixation with plate& screws. 
The osteotomy converts the shearing stresses at the fracture site into compressive forces, thus enhancing fracture union. 
The line of weight bearing after osteotomy passes from the head to the distal fragment. It, therefore, bypasses fracture site. 
By this osteotomy the head is supported by the distal fragment ( armchair effect) This helps the limb in taking weight on walking.
This operation is rarely done nowadays.
Malunited intertrochantric fracture of femur
Nonunion transcervical neck fracture of femur
Nonunion lateral condyle fracture of humerus
Malunited supracondylar fracture of humerus