INDICATIONS AND CONTRAINDICATIONS

Theoretically, ITO provides correction of the femoral axis in the frontal, the sagittal, or the transverse plane with or without leg length shortening.^1,³ Historically, the basic rationale for ITO was to reduce or improve the distribution of forces loading the hip, and numerous indications led surgeons to perform this procedure (Table 7-1). Nevertheless, total hip arthroplasty has supplanted ITO for several reasons, including difficult definition of the indications, the demanding nature of the intraoperative technique for ITO, and the unpredictability of its results. Presently, ITO should be considered only when the correction provides improvement in coverage, containment of a normal head portion, leg alignment, or congruency.

TABLE 7-1 INDICATIONS FOR DIFFERENT TYPES OF INTERTROCHANTERIC OSTEOTOMIES

Frontal Plane
Valgus osteotomy	Femoral neck pseudarthrosis
	Marked post-traumatic varus deformities
	Circumscribed anterolateral necrosis of the femoral head or epiphyseal dysplasia with intact medial part of head
	Equivalent of improved hip joint congruency on functional radiographs (or fluoroscopy) in adduction, in particular when accompanied by an adduction contracture
	≥15 degrees of passive adduction with pain relieved in adduction (with or without flexion)
Varus osteotomy	Marked coxa valga with a neck-shaft angle >140-150 degrees
	Valgus head, in particular when the fovea lies in the weight-bearing zone of the acetabulum
	Circumscribed anteromedial necrosis of the femoral head or epiphyseal dysplasia with intact lateral part of head
	Equivalent of improved hip joint congruency on functional radiographs (or fluoroscopy) abduction, in particular when accompanied by an abduction contracture
	Developmental hip dysplasia with concomitant malposition in valgus of the proximal femur, on the condition that a pelvic osteotomy cannot sufficiently restore the femoral coverage
	≥15 degrees of passive abduction with pain relieved in abduction (with or without flexion)
	Osteochondrosis dissecans
Sagittal Plane
Flexion osteotomy	In combination with valgus/varus intertrochanteric osteotomy to rotate altered segments out of the weight-bearing zone
	Slipped capital femoral epiphysis with excessive posterior tilt of the femoral head
Extension osteotomy	Fixed flexion contracture (rare)
Transversal Plane
Rotational osteotomy	In combination with varus osteotomy, eventually acetabuloplasty, persisting marked coxa valga with anteversion exceeding the normal age-related angle of anteversion by 20 degrees

The classic and strongest indication for ITO is post-traumatic deformity or nonunion, particularly of the femoral neck, for which most patients require valgus correction. Today, isolated varus ITO is rarely indicated. A good indication for ITO is a hip with a mild dysplastic acetabulum in combination with a valgus deformity of the neck that eventually leads to excessive antetorsion. In the case of moderate to clear dysplasia, varus ITO is rarely done now because rotational reorientation pelvic osteotomy, which addresses the problem at the acetabular site (the site of the main pathomorphology) has overtaken its role. An exception is the combination of a varus/valgus ITO and an acetabular reorientation procedure to improve the joint congruency further in severe femoral/acetabular dysplasias or after Perthes disease.

Intertrochanteric flexion or extension osteotomy for osteonecrosis has declined in popularity because of its questionable long-term results. This procedure may still be used for treatment of early-stage necrosis, however, with a circumscribed segmental extension of the lesion. A second indication for flexion/abduction osteotomy may be a slipped capital femoral epiphysis with an excessive posterior tilt of the femoral head. Table 7-2 lists absolute and relative contraindications for ITO.

TABLE 7-2 ABSOLUTE AND RELATIVE CONTRAINDICATIONS FOR INTERTROCHANTERIC OSTEOTOMY

Absolute Contraindications

Severe osteoporosis

Advanced osteoarthritis with marginal osteophytes

Marked spasticity or excessively stiff hip

Inflammatory arthritis

Joint incongruency, made worse with adduction if valgus osteotomy or with abduction if varus osteotomy is planned

Relative Contraindications

Obesity (body mass index >30)

Age >60 years

Cigarette smoking

PREOPERATIVE PLANNING

Preoperative workup includes a complete history and physical examination. An anteroposterior pelvic radiograph of the entire pelvis is needed with the legs in slight internal rotation to compensate for femoral antetorsion. Depending on the direction of the correction in the frontal plane, and to ensure joint congruency postoperatively, an anteroposterior radiograph of the hip can be performed in maximal abduction where varus (adduction) osteotomy is indicated or in adduction where valgus (abduction) osteotomy is indicated. CT or MRI can be obtained depending on the circumstances. The latter is helpful in the diagnosis of periarticular soft tissue processes, in the assessment of extent of femoral head necrosis, and in the assessment of labral and chondral damage.

Preoperative drawing and templating is mandatory to determine the surgical steps exactly and to anticipate intraoperative difficulties. The surgeon should take the leg axis into consideration and use reference points for intraoperative identification of the entry point and direction of the implant, the level and direction of osteotomy, and the desired leg length.

A varus osteotomy is planned as follows (Fig. 7-1).

FIGURE 7-1 A-C, Five steps of planning the varus/varus osteotomy. (1) Determination of the innominate tubercle (IT) as a reference. (2) Drawing of the level of the osteotomy aimed at the cranial extension of the lesser trochanter and measurement of distance a. (3) Determination of the point of the dense bone trabeculae (D) approximately 10 mm below the superior cortex of the neck. (4) Drawing of a line through point D with the designated correction alpha angle. (5) The intersection point with the lateral cortex represents the entry point E of the blade with a distance b from the IT. With more than 25 degrees of correction, a trochanteric osteotomy has to be performed with resection of a wedge with the same alpha angle.

1. Determination of the innominate tubercle (IT).

2. Drawing of the level of osteotomy, which should be aimed at the cranial extension of the lesser trochanter. The distance between the innominate tubercle and the line of osteotomy, distance (A), serves as intraoperative reference for the level of osteotomy. There is a magnification factor of approximately 10% between the radiograph and the real anatomy.

3. Determination of the point of dense bone trabecula (D) which lies approximately 10 mm below the superior cortex of the neck and which represents the optimal placement of the blade.

4. Drawing of a line through point D with the designated correction alpha angle relative to the ITO. The intersection (point E) between this line and the lateral femoral cortex represents the entry point for the blade. The vertical distance b between points IT and E can be easily reproduced intraoperatively.

5. A trochanteric osteotomy is necessary in variation osteotomies exceeding 25 degrees. The thickness of the osteotomized trochanter must be at least 1 to 1.5 cm. An additional wedge with the same correction alpha angle has to be resected to guarantee an exact apposition of the osteotomized trochanter fragment.

The first planning step of a valgus osteotomy starts with the determination of the correction angle (Fig. 7-2). In case of a femoral neck pseudarthrosis, the aim is to convert shear stresses into compressive forces, increasing the likelihood of union. The amount of valgization can be determined by subtracting 16 degrees (which represents the normal compression vector force on the hip [Fig. 7-3]) from the Pauwel angle (defined as the angle between the pseudarthrosis and a horizontal line). Next, the site of osteotomy, the innominate tubercle, the distance a, and point D are determined. The virtual blade is overlaid on the anteroposterior radiograph by constructing the planned valgus alpha angle relative to the femoral axis and by caudocranial translation through point D. The distance a between the innominate tubercle and the entry point E of the blade can be used as an intraoperative reference.