Dr. Kristaps Keggi described the standard trochanteric osteotomy in 1979 for the DAA.⁵ Today, indications for this osteotomy are limited to rare cases in which extensile acetabular exposure is required, such as during complex acetabular revision or in patients with laxity of the abductors and concomitant global instability.

The standard osteotomy starts by preparing the anterior aspect of the femur. No muscles have to be detached because the origin of the abductor and vastus lateralis muscle is located posteriorly and laterally. A blunt retractor is then inserted behind the greater trochanter. An oscillating saw or an osteotome is used to make the osteotomy from anterior to posterior at an angle <45° to the femoral diaphysis. The osteotomy is then freed of tethering soft tissue attachments, and the fragment can be reflected laterally or proximally. Without the greater trochanter attachment, the femur can be readily mobilized, and the in-line approach to the femoral canal becomes easy. However, the extra exposure for the acetabulum is limited. For other approaches, several modifications, such as the chevron osteotomy, have been described.⁶ This biplane osteotomy should provide anteroposterior and rotational stability. Some authors use two to four monofilament wires⁷ with different techniques of tunnels in a vertical and horizontal plane through the osteotomized fragment. Claw plates, cables, or standard plates can also be used for fixation of the fragment.

Nonunion rates of 0.5% to 38% with trochanter pain, abductor insufficiency, and hip instability have been reported.⁶ Therefore, we believe the indications for this osteotomy are limited.

Indications for the trochanteric slide osteotomy are rare and similar to those for a standard osteotomy.⁸ The proposed advantage is an intact vastus lateralis and gluteus medius attachment, which compresses the fragment with a medially directed force. This prevents proximal migration of the fragment.

The osteotomy is initiated anteriorly with an oscillating saw and is taken in a posterior direction. The caudal extent of the osteotomy is just distal to the vastus ridge. The fragment is usually fixed with monofilament wires or cables passed medially around the proximal femur and around the trochanteric fragment. Alternatively, a cable grip system, cables alone, or a plate system can be used. Cable grip systems have better radiologic outcomes compared with other fixation systems.⁹

High rates of nonunion from 1.5% to 38% have been reported.^10,11 More recent data showed lower nonunion rates (4%) compared with a standard trochanteric osteotomy (15%-20%).¹²

The ETO was first described by Younger et al¹² as an alternative method to the anterior trochanteric osteotomy described by Wagner.¹³ The ETO is frequently used in revision THA for the removal of a well-fixed femoral component or cement removal from the femoral diaphysis. The ETO has also been described for difficult primary THAs (eg, proximal femoral deformity and hip dysplasia). Note that the ETO should not be performed in patients with severe osteolysis of the proximal femur.

Most authors recommend a lazy S extension of the approach for the technique of an ETO.⁴ This is described in Chapter 23. In brief, the ETO is performed on the lateral aspect of the femur and carried out distally from the greater trochanter. The aim is to maintain an intact muscle-osseous sleeve, which is composed mainly of the gluteus medius, greater trochanter, vastus lateralis, and femoral diaphysis fragment.¹² The length of the osteotomy should be measured preoperatively so that the femoral stem can be easily removed and adequate fixation can be provided. The femoral osteotomy is performed anteriorly to open the femur fragment posteriorly, which is opposite to that described by Younger et al.¹² Multiple drill holes in regular intervals might avoid creating a potential stress riser at the junction of the vertical and horizontal cuts. A saw is used to cut the anterior lateral aspect of the cortical bone, lateral to the femoral component into the femoral canal. Then, the osteotomy can be completed posteriorly. A distal transverse cut is completed up to the implant with a saw or an osteotome. Then, a posterior
hinge is created, and the osteotomy is opened using two osteotomes against each other. Usually, the mean length of the osteotomy is 12 to 14 cm^14,15 (Figure 31.1).

Reduction and fixation of the fragment begin by placing the leg in slight internal rotation and neutral abduction. The authors recommend implanting the revision stem before reattaching the osteotomy. This ensures proper distal diaphyseal fixation of the implant because there is no proximal interference from the fragment or the osteotomy. In addition, this provides direct visualization of the distal implant fit, which ensures proper implant sizing. The ETO fragment can be reduced with a clamp.