Extended Greater Trochanteric Osteotomies

Key Concepts

Extended greater trochanteric osteotomies provide wide access to the femoral canal and hip joint. The most common indications are in revision total hip arthroplasty (THA) procedures with well-fixed or broken femoral implants that require removal, extensive bone cement that requires removal, or bone deformity limiting safe longitudinal access to the femoral canal (Figure 23.1A-F).
Most commonly extended greater trochanteric osteotomies are used to facilitate removal of well-fixed cemented or uncemented femoral components. Additional indications include access to the femoral canal when the greater trochanter overhangs the implant or circumstances in which an osteotomy is needed to correct proximal femoral deformity.
There are two main categories of extended trochanteric osteotomies (ETOs): those that elevate the lateral one-third of the circumference of the femur and those that elevate the anterior one-third of the circumference of the femur (Figures 23.2 and 23.3).
For all types of ETO, to maximize healing potential, preserve the blood supply of the ETO fragment by retaining muscle (abductor and vastus lateralis) attachments to most of the fragment.
Preoperative templating is critical. Plan the length of osteotomy and account for any proximal femoral deformity. Make sure the osteotomy is long enough to gain enough exposure to remove implant or cement mantle and yet leave sufficient diaphysis to allow for solid fixation of a the planned revision femoral component.
If the patient has a notable anterior bow of the femur or if you are planning insertion of a very long straight stem, consider an anterior osteotomy as this will allow straight access to the femoral canal and minimize risk of distal anterior perforation

Sterile Instruments and Implants

Thin oscillating saw
Broad osteotomes and narrow osteotomes
Power burr with fine side cutting tip
Cerclage cables and wires
Bennett retractors

Surgical Approaches

The type of surgical approach is dictated by the type of ETO.

Figure 23.1 ▪ Indications for extended trochanteric osteotomy (ETO). Distal cement mantle (A). Proximal femoral deformity (B). Stem subsidence with overhanging greater trochanter (C). Well-fixed uncemented stem requiring removal (D). Well-fixed cemented stem requiring removal (E). Broken femoral stem (F).

Preoperative Planning

Template choice of stem, typically a long uncemented stem, either fluted tapered or fully porous coated.
Plan the length of the osteotomy and measure the distance from the tip of greater trochanter (usually 12-18 cm) for intraoperative reference. Make sure the osteotomy is long enough to allow safe removal of the stem or cement mantle but also leaves enough diaphyseal bone to allow for solid implant fixation. If an extensively porous-coated cylindrical stem is being removed, it is important to extend the planned osteotomy to a point where the stem is cylindrical to allow for trephines to pass over the stem for easier removal.

Figure 23.2 ▪ Laterally based extended trochanteric osteotomy (ETO). A, Femur with well-fixed stem requiring removal. B, Osteotomes used to open the osteotomy. C, Exposure of the femoral implant after osteotomy. (Used with permission of Mayo Foundation for Medical Education and Research. All rights reserved.)

Bone, Implant, and Soft Tissue Techniques

Lateral Extended Trochanteric Osteotomy

Position patient in a lateral decubitus position and perform posterior approach to the hip up to but not including opening the pseudocapsule.
If the proximal canal is not filled by the implant, the posterior hip capsule can be kept intact (thereby optimizing hip stability) and the hip dislocated anteriorly. To use this technique there must be sufficient space between the implant and lateral femur (Figure 23.4A and B) to perform the proximal anterior longitudinal limb of the osteotomy by sliding a saw from posterior to anterior. If there is not sufficient lateral bone to allow this technique (Figure 23.5A and B), complete a formal posterior approach to the hip and dislocate the hip posteriorly.

Identify the vastus lateralis and divide the posterior portion of the vastus lateralis longitudinally just anterior to the linea aspera. There will often be deep perforating vessels coming through the septum posteriorly. These vessels should be ligated or cauterized to minimize excessive bleeding. Use a ruler to mark the level of the transverse limb of the osteotomy by measuring the distance from the tip of the greater trochanter. The length of the osteotomy is usually at least 12 cm and rarely more than 16 cm. At this level, elevate a small amount of vastus lateralis (about 2-3 cm wide) from the lateral

femur working posterior to anterior. This will be the level of the distal and transverse aspect of the osteotomy. Once the vastus lateralis is elevated in this small section, a blunt retractor (such as a Bennett retractor) can be placed to retract the vastus lateralis anteriorly (Figure 23.6).

Figure 23.3 ▪ Anteriorly based extended trochanteric osteotomy (ETO). A, Line of muscle splitting. B, Osteotomes used to open the osteotomy. C, Exposure of femoral implant after osteotomy. (Used with permission of Mayo Foundation for Medical Education and Research. All rights reserved.)

Figure 23.4 ▪ A, Preoperative radiograph of patient with well-fixed dual modular neck femoral stem requiring removal. There is sufficient thickness of lateral bone to allow the proximal anterior longitudinal osteotomy to be made with a saw from posterior to anterior without first dislocating the hip. B, Postoperative radiographs after revision with laterally based extended trochanteric osteotomy (ETO).

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