Philipp Henle, Moritz Tannast, and Klaus A. Siebenrock
DEFINITION
This chapter focuses on the use of intertrochanteric adduction (varus) osteotomy to reorient the proximal femur to improve femoral head coverage and hip joint congruency. Clinical conditions that constitute good indications for this operative technique are:
Mild epiphyseal dysplasia of the femoral head with the lateral part of the head intact
Circumscribed anteromedial necrosis or osteochondritis dissecans of the femoral head
Valgus head, in particular when the fovea lies within the weight-bearing zone of the hip joint
Developmental dysplasia of the hip, when the procedure is performed in conjunction with pelvic osteotomy to obtain better joint congruences
Posttraumatic joint incongruence
The prerequisite for a successful operative treatment is the possibility that the joint incongruence can be improved.
The same operative technique can be used for correction of the proximal femur in abduction, flexion and extension, and rotation, and every combination thereof.
ANATOMY
The hip joint is a strong and stable multiaxial ball-and-socket synovial joint. In the standing position, the entire weight of the upper body is transmitted through the hips to the lower extremities.
Because the depth of the acetabulum is increased by the fibrocartilaginous 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 transmission of weight force.
The main blood supply of the femoral head is from the circumflex femoral arteries, especially the medial circumflex femoral artery, a fact that must be considered when operating in this area.
PATHOGENESIS
A variety of pathologic processes can affect hip joint congruence. The most important of these are listed earlier in this chapter.
Incongruences of the hip joint are associated primarily with a reduced weight-bearing area, which increases the load on the remaining joint surface.
NATURAL HISTORY
If the joint load constantly exceeds the resistibility of the articular cartilage, arthrotic changes begin to develop. If untreated, this condition results inevitably in a progressive destruction of the hip joint.
Current surgical treatment for advanced stages of this degenerative process is dominated by total hip replacement due to the overwhelming success of this intervention.
PATIENT HISTORY AND PHYSICAL FINDINGS
To assess duration and severity of symptoms as well as potential actuating circumstances, a complete history must be taken, including childhood disorders such as developmental hip dysplasia, sustained Perthes disease, or slipped capital femoral epiphysis.
General examination of the hip always should include active and passive range of motion as well as gait inspection and leg length comparison.
Specific physical examination methods include:
Anterior impingement. The test is positive if the passive movement provokes groin pain, which relates to a femoroacetabular impingement at the anterior wall or a labral tear.
Apprehension test. The test is positive if the patient complains about a feeling of imminent joint luxation, which indicates an 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 slight internal rotation of the hip to compensate for the femoral antetorsion.
Other helpful projections are (1) an axial view, (2) the false-profile view as a true lateral projection of the femoral head and neck, 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 MRI or CT scans are optional. They may offer additional information on accompanying lesions on labrum or cartilage or the extent and stage of a femoral head necrosis.
SURGICAL MANAGEMENT
Preoperative Planning
A preoperative drawing is mandatory. It should make it possible to determine the level and localization of the osteotomy, as well as entry point and direction of the implant in relation to reference points that can be identified intraoperatively.
Because preoperative drawing is a crucial part of the operative technique, it is covered fully in the Techniques section.
FIG 1 • Preoperative imaging. Standard AP radiograph of the pelvis (A), axial view (B), and false-profile view (C) of a patient with mild hip dysplasia. D. Radiograph of the pelvis with hips in maximum abduction to determine the optimal degree of varization and to simulate the expected head position and coverage. E. MRI scanning of the hip can provide additional information on the joint cartilage, the labrum, and a possible associated femoral head necrosis.
Positioning
A lateral decubitus position on the contraleral side is preferred, allowing unimpeded access to the operation field and free movement of the afflicted leg (FIG 3).
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 washing and 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, allowing a better view of the anterior joint capsule, but this approach is not recommended when an osteotomy of the greater trochanter is planned.
FIG 2 • A,B. Postoperative radiograph with the desired varus correction of the right hip. An additional distalization of the greater trochanter was performed in this patient.
FIG 3 • A. Patient in lateral decubitus position, stabilized with arm and side rests. A foam pillow is placed between the legs. B. The affected leg is draped separately in a bag to allow free movement of the hip joint. C. View of the prepared operating field, centered over the greater trochanter.
TECHNIQUES
PREOPERATIVE DRAWING
Outlines of the femur and pelvis are transferred from the radiograph to drawing paper. Alternatively, computer programs are available that allow preoperative planning directly on digital images within a PACS (picture archiving and communications systems) viewer on the computer.
The drawing should focus on the following (TECH FIG 1):
Identification of the innominate tubercle as the lateral, intraoperatively detectable reference point
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 angel 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 and can be reproduced intraoperatively.
An additional trochanteric osteotomy is recommended in intertrochanteric osteotomies (ITOs) with a correction angle of more than 25 degrees.
The osteotomized trochanter should be at least 10 mm thick, and the angle of the resected wedge should be equal to the resection angle to allow an accurate apposition of the trochanter fragment.
When transferring the plan to the surgical situs, it must be remembered that radiographs show a magnified projection of the real anatomy.
Therefore, all measured distances (not angles) must be reduced by around 10%.
TECH FIG 1 • A. The osteotomy level is determined in relation to the innominate tubercle (IT), the point of dense bone trabeculae (D), and the blade position with the desired correction angle (α), after which the blade entry point (E) can be determined. The gray area represents the optional trochanteric osteotomy, which is recommended only when the correction angle exceeds 25 degrees. B. Final plate position after intertrochanteric adduction osteotomy without trochanteric osteotomy. C. Final plate position after an additional trochanteric osteotomy.
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, the 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 can be divided erroneously.
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.
TECH FIG 2 • Approach. A. The skin incision is centered over the greater trochanter, starting 3 to 4 cm cranial of the tip of the trochanter and reaching 20 to 30 cm distally along the axis of the femur. B.Intraoperative view of the incision. The greater trochanter is marked as an anatomic landmark. C. The fasciotomy is performed longitudinal to the axis of the femur. D. After retraction of the fascia, the greater trochanter is exposed. E. L-shaped detachment of the vastus lateralis at its origin. F. Transgluteal approach as a variant. G. This approach allows a better view of the anterior capsule.
The mobilized muscle is retracted anteriorly to expose the lateral aspect of the femur up to the first perforating arteries, which usually are 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.
The transgluteal approach allows a better view of the anterior joint capsule, but it is discouraged when a trochanteric osteotomy is planned.
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 Hohmann retractors (8 mm), which are inserted on the acetabular rim just proximal to the labrum with the hip in a slightly flexed position.
At this time direct visual assessment of the femoral anteversion and part of the articular cartilage is possible, if the leg is externally rotated.
At the level of the blade entry point, which was determined on the preoperative drawing in relation to the innominate tubercle, a cortical fenestration 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 also was determined by the preoperative drawing, can now be measured with quadrangular positioning plates and marked with a Kwire 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 until it has obtained some purchase.
The position is than 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.
TECH FIG 3 • Blade channel placement. A. Anterior capsulotomy in line with the femoral neck. After visualization of the anteversion of the femoral neck, a cortical fenestration is made at the blade entry point. B. Placement of two K-wires shows the desired direction of the blade, along which the seating chisel is inserted into the cortical window.
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.
It is recommended, therefore, 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.
TECH FIG 4 • Osteotomy. A. After placing two parallel K-wires proximal and distal of the planned osteotomy for later rotational control, the osteotomy is performed under protection of the surrounding soft tissue. B.Insertion of a broad chisel to spread the osteotomy. The chisel and the patient's foot are used as levers to mobilize the fragments.
BLADE INSERTION
Before the seating chisel is withdrawn, the blade-plate must be readily mounted on the inserter. 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.
TECH FIG 5 • A. Insertion of the blade into the channel formed by the seating chisel. B. For the final 10 mm, the blade is advanced with the impactor.
If the force necessary for insertion of the blade increases dramatically, the plate should be removed, the seating chisel again 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 3⁄4 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 a case 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, in particular of rotation 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.
TECH FIG 6 • Correction and plate placement. A. After the desired correction is reached and full contact of the plate with the lateral femur is achieved, the plate is held in place with a reposition forceps, and the first screw is placed through the plate. B. With good bone quality two screws distal to the osteotomy are sufficient. If bone quality is reduced, another screw can be inserted through the offset of the plate for additional stability.
POSTOPERATIVE CARE
The leg is positioned on a splint with 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 ossifications.
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 since the surgery.
OUTCOMES
Published studies after intertrochanteric adduction osteotomy for the treatment of hip dysplasia have reported good long-term outcomes,1 ranging from 63% to 87% after 21 to 26 years.
Treatment of an avascular necrosis of the femoral head with an ITO can expected to achieve good results in 65% to 90% of cases, depending on the radiographic stage of the AVN.
Data are limited on patients with osteochondritis dissecans treated with an ITO. Radiologic incorporation was achieved in more than two thirds of all patients.
COMPLICATIONS
Unsatisfactory correction
Incorrect blade placement
Malrotation
Femoral head necrosis
Delayed or non-union
Heterotopic ossifications
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.