Varus intertrochanteric osteotomy involves the reorientation of the proximal femur in order to improve femoral head coverage and joint congruency. It may serve either as a reconstruction or salvage operation. Varus intertrochanteric osteotomy may be beneficial in treating the following conditions^1,2:

   Developmental dysplasia of the hip. Although it is most commonly used in conjunction with a pelvic osteotomy, it has also been reported as an isolated procedure.

   Femoral head osteonecrosis. The osteotomy can remove a circumscribed necrotic lesion from the weight-bearing area.

   Coxa valga, in particular when the fovea lies within the weight-bearing zone

   Mild epiphyseal dysplasia of the femoral head with the lateral part of the head intact

   Posttraumatic joint incongruence

   Osteochondritis dissecans of the femoral head

   The ability to improve or maintain an adequate hip joint congruency is key to obtain satisfactory surgical results.

   Variations of the technique can be used for correction of the proximal femur in the coronal and sagittal plane,³ as well as to improve the rotational alignment.

ANATOMY

   The hip joint is an enarthrodial, polyaxial joint between the pelvis and the femoral head. Adequate joint congruency is crucial for well-functioning and normal load transmission across the hip joint.

   The acetabular labrum increases the femoral head coverage and participates in normal load transmission. Considering the labrum, more than half of the femoral head fits within the acetabulum.

   The femoral head is covered with articular cartilage except for the fovea.

   The central and inferior part of the acetabulum, the acetabular fossa, does not participate physiologically in load transmission.

   The medial circumflex femoral artery is the main blood supply of the femoral head. It is mandatory to protect it during hip preservation procedures.

PATHOGENESIS

   Diverse pathologies, including congenital and acquired hip conditions, can alter joint congruency.

   Abnormal hip joint congruency produces high-contact stress on the articular cartilage, predisposing the patient to end-stage osteoarthritis.

NATURAL HISTORY

   If load transmission forces across the hip joint constantly exceed the physiologic limits of the articular cartilage, degenerative changes are inevitable. If untreated, this condition results in progressive osteoarthritis.

PATIENT HISTORY AND PHYSICAL FINDINGS

   A complete medical history should be taken. Groin pain is the most important symptom in hip-related disorders. The severity and duration of pain, stiffness, and altered physical function should be asked. Previous trauma, childhood hip disorders, and the use of corticosteroids must be inquired about as part of the relevant medical history.

   General examination of the hip should always include active and passive range of motion as well as gait inspection and leg length comparison.

   Specific physical examination also includes the following:

   Anterior impingement test. The test is positive if passive movement provokes groin pain, relating to femoroacetabular impingement at the anterior wall or a labral tear.

   Apprehension test. The test is positive if the patient complains of imminent joint luxation, which indicates insufficient coverage of the femoral head.

IMAGING AND OTHER DIAGNOSTIC STUDIES

   A plain, anteroposterior (AP) radiograph of the entire pelvis is needed to determine the type of pathology in the femoral head or the femoral neck. The patient is positioned with 15 degrees of internal rotation of the hip to compensate for the femoral anteversion.

   Other helpful projections are (1) an axial view, (2) the false-profile view as a true lateral projection of the acetabulum, and (3) an oblique view on the acetabulum tangential to its superoanteromedial edge (FIG 1).

   An AP radiograph of the hip in maximal abduction also may be helpful to determine the optimal degree of correction.

   It simulates the postoperative position of the femoral head and the expected joint congruency.

   Pelvic magnetic resonance imaging or computed tomography scans are optional. They may offer additional information on accompanying lesions on labrum or cartilage or the extent and stage of femoral head necrosis.

   A postoperative AP pelvis view as well as a cross-table view of the hip are useful to evaluate the surgical correction (FIG 2).

SURGICAL MANAGEMENT

Preoperative Planning

   A preoperative drawing is mandatory. It serves to determine the level and localization of the osteotomy, as well as the entry point and direction of the implant in relation to reference points that can be identified intraoperatively.

   Because a preoperative drawing is a crucial part of the operative technique, it is described in the Techniques section.

Positioning

   A lateral decubitus position on the contralateral side is preferred, allowing unimpeded access to the operation field and free movement of the afflicted leg (FIG 3). However, some surgeons prefer the supine position.

   Intraoperative fluoroscopy is strongly recommended. Therefore, a radiolucent operating table must be used, and the position of the C-arm and image intensifier should be checked before draping.

Approach

   The standard procedure uses a lateral approach with an L-shaped detachment of the vastus lateralis muscle, thus increasing the gap medial to the abductors.

   Optionally, a transgluteal approach also can be used. It allows better visualization of the anterior joint capsule. However, this approach is not recommended when an osteotomy of the greater trochanter is planned.

TECHNIQUES

   Preoperative Drawing

   Outlines of the femur and pelvis are transferred from the radiograph to drawing paper. Alternatively, some software allow preoperative planning directly on digital images. Magnification of the images should be considered when transferring the planning to the actual surgery. It applies for the measured distances and not for the angles.

   The drawing should focus on the following (TECH FIG 1):

   Identification of the innominate tubercle as the most lateral, intraoperatively detectable point of reference

   Drawing of the planned osteotomy perpendicular to the femoral shaft axis. The level of the osteotomy is determined by aiming at the cranial extension of the lesser trochanter.

   Measurement of the distance between the osteotomy and the innominate tubercle

   Determination of the point within dense bone trabeculae for optimal blade placement

   Blade position is now determined by that point and the designated correction angle relative to the planned osteotomy.

   The intersection point of the outlined blade position and the lateral cortex marks the entry point of the blade. Its distance to the innominate tubercle is measured so it can be reproduced intraoperatively.

   An additional trochanteric osteotomy is recommended in those cases with an intertrochanteric correction angle of more than 25 degrees.

   The osteotomized trochanter should be at least 10 mm thick. The angle of the resected wedge should be equal to the resection angle to allow an accurate apposition of the trochanter fragment.

   Approach

   The approach begins with identification and marking of the greater trochanter as an anatomic landmark.

   A longitudinal skin incision of 20 to 30 cm is made centered over the greater trochanter, starting 3 to 4 cm cranial to the tip of the greater trochanter (TECH FIG 2).

   Subcutaneous tissue, fascia lata, and the trochanteric bursa are split longitudinally to expose the insertion of the gluteus medius and the origin of the vastus lateralis.

   To facilitate the exposure, the leg can be abducted to release the fascia lata.

   If the incision is placed too anteriorly, it may sever the tensor fasciae latae muscle. If placed too far posteriorly, the cranial part of the gluteus maximus may be erroneously incised.

   The vastus lateralis is detached at its origin in an L-shape, thus increasing the gap medial to the abductor muscles.

   The muscle is detached from the fascia at the posterior border with a knife and broad periosteal elevator until the entire lateral aspect of the femur is exposed.

   The mobilized muscle is retracted anteriorly to expose the lateral aspect of the femur up to the first perforating arteries, which are usually found 8 to 10 cm distal to the innominate tubercle. The vessels are ligated.

   A transgluteal approach may be used as an alternative.

   Here, the anterior part of the gluteus medius and the anterior insertion of the gluteus minimus are detached, and the incision is continued into the vastus lateralis.

   A step is cut in the posterior direction between the two muscles, allowing continuity to be maintained between both glutei and the vastus lateralis.

   During splitting of the gluteus medius, attention must be paid to the nerve branch supplying the tensor fasciae latae, which crosses 3 to 5 cm cranial to the insertion.

   Blade Channel Placement

   The anterior capsulotomy is performed in line with the femoral neck and extended to the labrum, which is preserved (TECH FIG 3).

   This approach does not affect blood supply to the femoral head.

   Capsulotomy and exposure of the femoral neck and head are facilitated by insertion of as many as three 8-mm Hohmann retractors, which are inserted on the acetabular rim just proximal to the labrum with the hip in a slightly flexed position.

   At this time, if the leg is externally rotated, direct visualization of the femoral anteversion and part of the articular cartilage is possible.

   At the level of the blade entry point, which was determined on the preoperative drawing in relation to the innominate tubercle, a cortical window measuring 15 × 5 mm is made.

   It lies almost completely anterior to an imaginary line dividing the lateral aspect of the greater trochanter into two equal parts.

   Previous marking of the window with a scalpel or an osteotome is recommended.

   The direction of the blade, which was also determined by the preoperative drawing, can now be measured with quadrangular positioning plates and marked with a K-wire inserted into the trochanter cranial to the cortical window.

   An additional K-wire is placed along the femoral neck and pushed into the femoral head to indicate the anteversion of the neck.

   Measurement should not be done too close to the origin of the vastus lateralis because the diameter of the femur decreases significantly over a distance of 2 to 3 cm.

   The U-shaped seating chisel is inserted into the cortical windows with the direction defined by the two K-wires.

   It is recommended that the chisel be introduced only after it has obtained some purchase.

   The position is then checked in all planes and the chisel readjusted if necessary.

   The seating chisel is advanced under continuous control of all three alignments into the femoral neck and head until the desired depth has been reached (generally 50 to 60 mm).

   Before the osteotomy is performed, the chisel is withdrawn slightly to make it easier to remove it later.

   Osteotomy

   The level of the osteotomy is identified in relation to the innominate tubercle, according to the preoperative drawing.

   An exact drawing obviates the need for palpation of the lesser trochanter.

   Two K-wires are placed into the femur in an anteroposterior direction, one proximal and one distal to the planned osteotomy to allow later rotational realignment (TECH FIG 4).

   The osteotomy is performed perpendicular to the long axis of the femur under continuous irrigation.

   The surrounding soft tissues, in particular posteriorly, must be protected with blunt retractors.

   The medial femoral circumflex artery runs approximately 15 mm proximal to the lesser trochanter, close to the bone, and can be easily injured.

   If an additional trochanteric osteotomy is performed, anastomoses from the internal iliac artery may be severed, invariably causing necrosis of the femoral head.

   Therefore, it is recommended that the anterior cortex be osteotomized first and the osteotomy completed posteriorly thereafter.

   A broad chisel (20 mm) is inserted to spread the osteotomy gap.

   The chisel and the patient’s foot are used as levers to mobilize the fragments in opposite directions.

   Manipulation with the seating chisel in the femoral neck must be avoided because this could lead to loosening.

   Blade Insertion

   Before the seating chisel is withdrawn, the blade plate must be readily mounted on the inserter. The blade and inserter must be in line with each other.

   For the first 2 to 3 cm, the blade is advanced manually with repeated pushes (TECH FIG 5).

   As long as the blade follows the channel, easy advancement should be possible.

   If the force necessary for insertion of the blade increases dramatically, the plate should be removed, the seating chisel should be reintroduced, the direction should be checked, and the plate insertion repeated.

   Hammer blows to advance the plate are allowed only after the direction of the blade has been confirmed. Otherwise, the blade can be pushed in the wrong direction or even perforate the femoral neck.

   During blade insertion, contact of the plate with soft tissue or the femoral shaft must be avoided because this might change the direction of the blade.

   Such contact is best prevented by positioning the thigh in adduction until three-fourths of the blade has been introduced.

   Once the distance between offset of the plate and bone has reached 1 cm, the inserter is removed and the blade is further advanced with the impactor until full contact with the bone is achieved.

   If an additional trochanteric osteotomy has been performed, the trochanter fragment is flipped over the blade through an already prepared window. The blade with the trochanter is then pushed into the femoral neck.

   Care must be taken not to split the trochanter fragment.

   Correction and Plate Placement

   Achievement of the desired approximation between plate and lateral cortex of the femoral shaft can be facilitated by manipulation of the leg. For rotational realignment, the previously inserted K-wires are used as references.

   After the plate is positioned, it is held against the bone with a reduction forceps (Verbrugge forceps; TECH FIG 6).

   Fixation of the plate to the distal fragment can be achieved in three ways:

   Without interfragmentary compression

   With interfragmentary compression obtained by use of the gliding holes

   With interfragmentary compression obtained with a plate tensioner

   The amount of compression depends on the degree of optimal stability as well as the surgeon’s preference.

   When using a plate tensioner, compression must be applied judiciously because strong compression may cause a loss of correction, especially in cases of reduced bone quality.

   If no trochanteric osteotomy is performed, the use of gliding holes is recommended.

   If further stability is needed, an additional screw can be inserted through the hole in the offset and engaged into the proximal fragment.

   While the screws are being tightened, rotational alignment of the fragments must be closely observed.

   External malrotation may occur when only the posterior rim of the plate is in contact with bone.

   The stability of the fixation is checked once the first screw has been tightened and the reduction forceps is still in place.

   The hip is put through a full range of motion, with the hip in 90 degrees of flexion.

   If the fixation proves to be stable, the second screw is inserted.

   With good bone stock, two bicortical screws are sufficient.

   In cases in which an additional intertrochanteric osteotomy is performed, the removed bone wedge is inserted into the lateral gap between the two main fragments.

   The use of a plate tensioner is preferable because its use reduces the risk of revalgization.

POSTOPERATIVE CARE

   The leg is positioned on a splint with the hip and knee in slight flexion.

   The patient is taken off bed rest on day 1 or 2, with partial weight bearing (15 kg) for 8 weeks.

   Non–weight bearing, which necessitates that the operated hip be held in flexion, leading to increased strain on the osteotomy, should be avoided.

   Physical therapy is required only for gait training using canes.

   Indomethacin (75 mg once daily) is given for 3 weeks for the prevention of heterotopic ossification.

   Radiographic follow-up is done after 6 weeks.

   At 6 weeks after the operation, strengthening exercises of the abductor muscles can be started.

   Final radiographic follow-up is done 1 year after surgery.

   The implant is removed only in case of symptoms such as soft tissue irritation or trochanteric bursitis and not before 1 year postoperatively.

OUTCOMES

   Published studies after intertrochanteric osteotomy for the treatment of hip dysplasia have reported good long-term outcomes, ranging from 63% to 87% after 21 to 26 years.¹

   Treatment of femoral head osteonecrosis with an intertrochanteric osteotomy can be expected to achieve good results in 65% to 90% of cases, depending on the radiographic stage.

   Data are limited on patients with osteochondritis dissecans treated with an intertrochanteric osteotomy.

COMPLICATIONS

   Unsatisfactory correction

   Incorrect blade placement

   Malrotation

   Femoral head necrosis

   Delayed or nonunion

   Heterotopic ossification

   Femoral or sciatic nerve injury

REFERENCES

1.   Santore RF, Kantor SR. Intertrochanteric femoral osteotomies for developmental and posttraumatic conditions. Instr Course Lect 2005;54:157–167.

2.   Siebenrock KA, Ekkernkamp A, Ganz R. The corrective intertrochanteric adduction osteotomy without removal of a wedge. Oper Orthop Traumatol 2000;8:1–13.

3.   Turgeon TR, Phillips W, Kantor SR, et al. The role of acetabular and femoral osteotomies in reconstructive surgery of the hip: 2005 and beyond. Clin Orthop Relat Res 2005;441:188–199.