The "Inside-Out" Anterior Osteotomy of the Proximal Femur via the Direct Anterior Approach in Revision Hip Arthroplasty

Abstract

Osteotomy techniques used for wide exposure during femoral component revision include the extended trochanteric osteotomy and its modifications. We describe an anterior proximal femur osteotomy technique starting from the inside of the femoral canal at the bone-implant interface and heading outward. The technique is used in conjunction with the extended direct anterior approach and allows direct access to and visualization of the anterior, medial, and lateral bone-implant interfaces. This technique is most useful for the removal of collared, fully hydroxyapatite-coated double-tapered femoral stems, in which bone-implant interfaces need to be accessed for removal of a well-osseointegrated hip arthroplasty implant.

Keywords: Direct anterior osteotomy; Femur osteotomy technique; Revision hip osteotomy.

Appendix Figure 1

Lateral radiograph of the femur demonstrating the plane of osteotomy on the anterior aspect of the component. The distal extent of the osteotomy can be measured from the proximal aspect of the stem.

Appendix Figure 2

A round burr (a) is used to clear trochanteric bone overlying the lateral shoulder (b) of the implant, creating a path for eventual removal.

Appendix Figure 3

Specialized proximal femoral osteotomes with modular handle (Exodus). (a) Flat, beveled osteotome for anterior and posterior interfaces (b) Lateral interface osteotome (c) Medial interface osteotome as it (d) advances along medial bone-implant interface.

Appendix Figure 4

Synthetic bone model demonstration of the path of osteotomes used to divide the proximal bone-implant interface (as seen from anterior view point). The anterior wall fragment is removed to demonstrate the location of the osteotomy.

Appendix Figure 5

Double-sided reciprocating saw is introduced along the anterior bone-prosthesis interface as distal as possible. Video 1: Click here.

Appendix Figure 6

(a) After formation of lateral and medial limbs of osteotomy with the reciprocating saw from proximally in ‘inside-out’ fashion, the tip of the saw is pushed through lateral cortex and digitally palpated. (b) The leg is then internally rotated, the vastus lateralis is elevated and retracted anteriorly. The saw tip is visualized, and the osteotomy is completed from ‘outside-in,’ following the plane of the proximal portion of the osteotomy.

Appendix Figure 7

Multiple osteotomes are introduced laterally in a sequential manner to free and open the anterior osteotomized fragment. Video 2: Click here.

Appendix Figure 8

Synthetic bone model demonstration of the 3 limbs of the osteotomy with fragment hinged medially.

Appendix Figure 9

Cadaveric dissection demonstrating visualization of the femoral component after mobilization of the osteotomy fragment. Proximally, a longitudinal separation of the interval between the gluteus minimus (attached to the trochanteric portion of the anterior osteotomized fragment) and gluteus medius (attached to the greater trochanter) allows full visualization of the medial bone-implant interface below the collar of the femoral component. Video 3: After wedging the osteotomized fragment open, the pencil-tip burr is used to divide the medial and lateral bone-implant interfaces. Click here.

Appendix Figure 10

Retrograde, axially-based component extraction demonstrating minimal proximal femoral bone loss.

Appendix Figure 11

Postoperative anteroposterior radiograph of the hip demonstrating revision stem placement and fixation of the osteotomy site.