Surgical Technique for Intertrochanteric Osteotomy

A standard lateral approach is used for all intertrochanteric osteotomies. The vastus lateralis is exposed by incising the fascia lata and reflected with Hohmann retractors to visualize the lateral femur (Figure 32-1, A). The vastus lateralis is sharply removed in the avascular plane from the vastus ridge. The vastus lateralis is detached from the intermuscular septum by blunt dissection, which allows for a wide inspection of the upper femur. Several perforating branches of the profunda femoral artery traverse the vastus lateralis and should be ligated correctly to avoid a postoperative hematoma; care should be taken so that the blunt dissection does not damage these vessels (see Figure 32-1, B). If it is necessary to inspect the hip joint, the approach can be extended proximally (i.e., the Watson-Jones approach), and the joint capsule can be opened to inspect the joint. The joint capsule is not routinely opened but rather only opened when indicated (e.g., for hump resection in a post-SCFE deformity). The linea aspera is decorticated. The seating chisel is inserted in the correct position, and the rotation is marked by placing a K-wire on each side of the planned osteotomy. Before this osteotomy is made, the seating chisel should be pulled back approximately 1 cm. An osteotomy parallel to the seating chisel is then made just proximal to the lesser trochanter (see Figure 32-1, C). Depending on the desired correction, a full or half wedge is removed to allow for the calculated varus–valgus or flexion–extension correction. During the osteotomy, blunt Hohmann retractors are placed around the femur to protect the femoral vessels and the femoral nerve. The definitive fixation is performed under compression with the classic AO (arbeitsgemeinschaft fur osteosynthesefragen) 90-degree or 100-degree blade plate, with different offsets that range from 10 mm to 20 mm. For cases in which extreme valgization is needed (e.g., for the treatment of femoral neck nonunions), a double-angled 120-degree or 130-degree blade plate can be used. For specific cases (e.g., intertrochanteric lengthening), a condylar plate is the preferred option. For all of our intertrochanteric osteotomies that involve the use of more or less right-angled blade plates, we performed the fixation under compression with the use of the AO compression device (see Figure 32-1, D and E). With the use of lateral compression, even open-wedge osteotomies heal without problems.

Figure 32–1 Preoperative pictures that illustrate the surgical technique of a classic intertrochanteric osteotomy. A, A standard lateral approach with an exposed vastus lateralis. B, Perforating branch of the profunda femoral artery is visible. C, After inserting the seating chisel and marking the rotation, a transverse osteotomy is made. D, Compression of the osteotomy with an AO compression device. E, After compression final fixation of the blade plate is performed.

Potential Pitfalls and Considerations for Intertrochanteric Osteotomy

Most of the described complications of intertrochanteric osteotomies can be avoided with the use of a good surgical technique. The incidence of a delayed union or nonunion can be greatly reduced with the proper use of an AO compression device. The anatomy of the intertrochanteric region is ideal for osteotomies, because the shape of this region allows for corrections in all planes while leaving large contact areas. Another advantage is the relatively good healing capacity of the metaphyseal bone.

In addition, the placement of the seating chisel or blade plate can cause problems. The occurrence of AVN caused by the osteotomy is a worry. The vascular supply of the femoral head is provided by branches of the dorsal circumflex artery, which can be damaged in the intertrochanteric fossa if the femoral neck is perforated by the seating chisel. This can be avoided with the correct placement of the seating chisel (Figure 32-2).

Figure 32–2 A, Schematic drawing of the vascular and surgical anatomy of the proximal femur. B, Surgical anatomy of the proximal femur with proper blade placement.

When flexion or extension is added to the osteotomy, the position of the femur after the osteotomy should be anticipated when planning the placement of the blade plate. For example, a seating chisel that is inserted too far anteriorly cannot be fixed properly to the femur after a flexion osteotomy (Figure 32-3).

Figure 32–3 Schematic drawing of the possible faulty placement of a blade plate in an flexion osteotomy.

Especially after a varus osteotomy, a long-lasting Trendelenburg gait can occur as a result of the relaxation of the gluteal muscles caused by the created femoral shortening. A good varisation should show a situation in which the tip of the major trochanter is not positioned higher than the center of the femoral head. If the center of the femoral head is positioned lower than the level of the tip of the major trochanter, the Trendelenburg gait could be permanent. If it is necessary to perform so much varisation that this occurs, a distalization of the major trochanter should be considered.

Surgical Technique for Shelf Plasty

We developed a special technique for adding superolateral bone grafts to the acetabulum in combination with an intertrochanteric osteotomy. In our clinic, 4% of all osteotomies performed involved patients with femoral head deformities and secondary osteoarthritis who required an additional shelf plasty.

For every procedure, an anterolateral approach was used that was similar to that used with a regular intertrochanteric osteotomy. The gluteal muscles are released with the use of an extracapsular osteotomy of the major trochanter. A cancellous–cortical bone graft is harvested from the ipsilateral interior iliac crest; this graft is bent into two or three blocks and predrilled for screw fixation. The joint capsule remains intact, but it is thinned on the superolateral side until head motion is visible. The supra-acetabular iliac bone is decorticated, and the prepared bone graft is fixated with 3.5-mm or 4.5-mm lag screws, with the patient’s leg in the calculated adduction or abduction position. When the function is tested in adduction, the graft should show plastic deformity. Some cancellous bone is pressed between the thinned joint capsule and the bone graft. A temporary screw fixation of the major trochanter is performed, if necessary, in combination with a distalization procedure (Figure 32-4). We performed distalization when the tip of the major trochanter was positioned higher than the center of rotation of the femoral head after correction. An intertrochanteric osteotomy is then performed in accordance with the standard AO technique; this technique is described earlier in this chapter.

Figure 32–4 Schematic drawing of the surgical technique of acetabular shelf plasty.

Potential Pitfalls and Considerations for Shelf Plasty

Two major pitfalls exist when creating a shelf plasty. First, care must be taken that the joint capsule is thinned enough to avoid a too-high position of the shelf plasty. Alternatively, the joint capsule should remain intact. If the joint capsule is too thick, the shelf plasty that is placed too high has no biomechanical function and is therefore useless.

The second major pitfall in our technique is a possible fracture of the major trochanter. Techniques in which the trochanter is reduced by the seating chisel cause, in our opinion, a higher risk of fracturing the trochanter, which could prove to be a disastrous complication. Temporary screw fixation can be performed quickly and safely, and it protects the patient from severe complications.

Surgical Technique for Intertrochanteric Lengthening

In many posttraumatic cases, a shortening of the affected leg is present. In these cases, lengthening can be achieved during the intertrochanteric correction. Correction at the intertrochanteric level can also correct a malrotation, if present, at the same time that corrections are performed in the other two planes.

When an adequate correction is obtained with the use of the previously described technique for an intertrochanteric osteotomy, the blade plate is temporarily held in place by a Verbrugge clamp. A laminar bone spreader is inserted into the osteotomy and opened until the desired lengthening is achieved. The blade plate glides beneath the Verbrugge clamp, thus allowing for lengthening but maintaining the correction. Instead of a laminar bone spreader, it is also possible to use an AO femoral distractor to achieve lengthening. Lengthening up to 3.5 cm can be safely performed without overstretching the nerves. The gap that is created at the intertrochanteric level is filled with corticocancellous bone graft from the iliac crest in combination with cancellous grafts along the decorticated linea aspera. After fixing the blade plate with 4.5-mm cortical screws, one or two of the distal screws are directed cephalad and should be fixated in the proximal fragment, thus creating extra stability (Figure 32-5).

Figure 32–5 Schematic drawing of the surgical technique of intertrochanteric lengthening. A, insertion of the seating chisel in the planned correction. B, placement of the blade plate. C, Correction of osteotomy is made. D, Rotatonial correction is obtained if desired. E, Lengthening can be performed with a laminar spreader. F, The gap is filled with corticocancellous grafts from the iliac crest.

Potential Pitfalls and Considerations for Intertrochanteric Lengthening

When a varus osteotomy is performed in combination with lengthening, the proximal fragment should be contoured with a chisel to avoid abutment with and the eventual fracturing of the lesser trochanter.

As with all surgical interventions, preoperative planning is important. When planning lengthening in combination with other intertrochanteric corrections, the leg-length alteration created by angular correction alone should be taken into account.

Lengthening in the intertrochanteric region is a difficult procedure. Make sure that the blade plate is completely inserted during the lengthening to avoid a completely unstable situation.

Coxa Valga (Antetorta) and Dysplasia

Deformities such as coxa valga (antetorta) and acetabular dysplasia often coexist. For hips in which the main deformity is on the acetabular side, an acetabulum realigning procedure should be the first choice, and, if necessary, it can be combined with a femoral osteotomy. In these cases, there is a relatively shallow and steep acetabulum that results in a decreased contact surface between the acetabulum and the femoral head (Figure 32-6). Isolated correction of the femoral side cannot solve this problem of containment fully and will fail to eliminate the dislocation force present. Thus, the osteotomy is doomed to fail. However, with some hip deformities, the main deformity lies on the femoral side, with only a mild acetabular dysplasia; the acetabulum might be shallow but not too steep. A varus osteotomy may improve the contact area between the femoral head and the acetabulum in these types of hips and possibly eliminate the dislocating force that is present. Good and long-lasting results may occur. This will not be the case if a fixed subluxation is present, because the weight-bearing surface and the dislocating forces are not altered, thus making the expected results of an intertrochanteric osteotomy poor. The improvement of containment can be judged preoperatively from an abduction correction view. However, currently no objective measurements exist to decide whether an acetabular realigning osteotomy or an intertrochanteric osteotomy is the preferred treatment for specific patients.

Figure 32–6 A 35-year-old female patient with symptomatic osteoarthritis as a result of coxa valga and mild dysplasia. A varus intertrochanteric osteotomy was performed. After 21 years, this patient was still free from complaints. A, Preoperative x-ray. B, Direct postoperative x-ray. C, X-ray after 21 years’ follow up.

The femoral antetorsion should be taken into account, because many of these patients have an increased femoral antetorsion that also needs to be corrected. A second consideration is that, after the varus osteotomy, the position of the tip of the major trochanter should not exceed the center of the femoral head to avoid a long-lasting Trendelenburg gait. If necessary, this can be addressed by performing a distalization of the major trochanter.

Slipped Capital Femoral Epiphysis

Not all patients who suffer from SCFE develop osteoarthritis during adulthood. However, this patient population has an increased risk of developing the condition. The pathophysiology behind these arthritic changes consists of acetabulofemoral impingement that is present in an insufficient or uncorrected SCFE or in unnoticed subclinical cases. A prominent part of the anterior metaphyseal femoral neck contacts the anterior part of the acetabulum during flexion. On the basis of the cause of this disorder, a valgus or flexion osteotomy with or without resection of the hump is the best solution. Because the disorder is only present on the femoral side, there is no role for acetabular realigning procedures in these pathologic changes. Early intervention appears to produce better results for this type of disorder. If, after the osteotomy, there is still some impingement present, the approach can be extended (i.e., the Watson-Jones approach) to perform an arthrotomy and to resect the hump with the use of osteoplasty.

Legg-Calvé-Perthes Disease

Not all patients who suffer from Legg-Calvé-Perthes disease during childhood develop osteoarthritis during adulthood, although, in many of these patients, a deformed hip joint is present. This deformity consists mainly of a broad and flattened femoral head with a short femoral neck in the varus position. In most cases, the acetabular side is also more or less abnormal, probably as a result of an adaptation of the developing acetabulum to the deformed femoral head.

Osteoarthritic changes develop in adulthood in 50% of patients with these hip deformities. It is most likely that these arthritic changes are caused by an acetabulofemoral incongruency. The origin of this incongruency lies in the fact that the deformed femoral head does not completely fit into the acetabulum. The aim of surgical intervention should be the early correction of this incongruency. The main theory that explains the development of osteoarthritis in these hips is the hinging of the femoral head on the edge of the acetabulum. The best known is the “hinge on abduction,” in which the lateral part of the femoral head hinges on the lateral part of the acetabulum. In these types of hips, a valgus extension osteotomy should be the preferred treatment to eliminate both the causative factor and the contractures that are present by realigning the leg. In hips, after Legg-Calvé-Perthes disease, in which the containment of the femoral head is not complete after osteotomy, adding an acetabular shelf plasty can produce excellent results (Figure 32-7). In some cases, valgization alone is not sufficient to restore the function of the abductors as a result of the relatively high position of the major trochanter. In these cases, a simultaneous distalization of the major trochanter is advised.

Figure 32–7 A, A 22-year-old male patient with a symptomatic hip deformity after Legg-Calvé-Perthes disease of both hips. A valgus osteotomy was performed with an acetabular roof plasty for both hips with 2 years in between. B, The radiographic result after 12 years is shown.

Posttraumatic Deformities

Posttraumatic deformities can be subdivided into deformities after acetabular fractures and malunions after proximal femoral fractures. Femoral neck malunion is a rare complication. If a malunion is present, it can cause an impingement between the femoral neck and the acetabulum, which causes early osteoarthritic degeneration. An early correction is required to avoid these osteoarthritic changes. In these posttraumatic deformities, a shortening of the affected leg is often present. Correcting the malunion with an intertrochanteric osteotomy also allows for simultaneous intertrochanteric lengthening. The direction of the deformity that is present in these malunions is mostly varus/extension; this means that the correction required is a valgus/flexion intertrochanteric osteotomy. The resection of the hump can be performed if partial impingement persists after the osteotomy.

Incongruency and osteoarthritis are common problems after acetabular fractures. With these fractures, cartilage damage occurs during the initial trauma, which makes the area susceptible to the development of osteoarthritis. If a malunited acetabular fracture that causes functional limitations coexists with an increased risk of the development of osteoarthritis, it seems logical to correct the acetabular side, where the deformity is located. However, these corrections are generally too complicated or even impossible. Therefore, it could be justifiable to adjust the normal femoral side to the abnormal acetabular side by aiming the largest part of the unaffected femoral head to the largest part of the unaffected acetabulum, thereby restoring normal joint motion and lowering the risk of osteoarthritic degeneration. In younger patients with more advanced osteoarthritic degeneration and in whom contractures are present, a palliative osteotomy could be considered. We have been able to document good outcomes in this patient group. This is probably the result of eliminating the contractures (i.e., realignment), and it could be caused by the biologic osteotomy effect as well.

Because of the average age of the patient with AVN, this seems like an ideal group for which to consider joint-saving surgery. This is also reflected in the large number of publications about this subject. The main thought behind intertrochanteric osteotomies in AVN is that the affected part of the femoral head is rotated away from the weight-bearing part of the joint, thus preventing collapse. This can be achieved because during intertrochanteric osteotomies corrections in all three dimensions are possible.

The literature shows no evidence of good outcomes in idiopathic AVN treated with intertrochanteric osteotomy. The benefit of intertrochanteric osteotomy is doubtful in this patient group. Most retrospective reports concern patients with atraumatic AVN, but some studies also include traumatic AVN, which demonstrates a better outcome. However, for these young patients, the outcome of intertrochanteric osteotomy remains unpredictable.

A special group of younger patients are those with a deformed femoral head after posttraumatic AVN, which is similar to a deformity that occurs after Legg-Calvé-Perthes disease. These patients may benefit from a valgus intertrochanteric osteotomy in combination with an acetabular shelf plasty.