Extended Trochanteric Osteotomy

 

 

 

BACKGROUND

P. Maxwell Courtney Wayne G. Paprosky

Removal of well-fixed femoral components has long been a challenge for the orthopedic surgeon in revision total hip arthroplasty (THA). Disrupting the bone-implant interface using standard techniques can be time consuming and potentially result in damage to the proximal femur. Wagner (1) first described in 1989 an anterior trochanteric osteotomy to facilitate removal of the femoral component. His reported technique involved making an extended anterior osteotomy of the greater trochanter, reflecting the anterior half of the abductors in continuity with the anterior aspect of the proximal femur. A modification of this technique, popularized by Younger and Paprosky, involved making a lateral trochanteric osteotomy and reflecting the abductors and vastus lateralis soft tissue attachments as a single continuous sleeve with the proximal lateral third of the femur (2). The extended trochanteric osteotomy (ETO) has become the workhorse for providing adequate surgical exposure for both revision and complex primary THA (3,4,5).

 

INDICATIONS

The ETO results in a controlled fracture of the proximal femur. The most common indication for utilization of the ETO is to facilitate removal of a well-fixed, extensively porous coated or diaphyseal fitting stem. The ETO is also a useful adjunct for removing a well-fixed proximal fitting stem when disruption of the bone-implant interface cannot be achieved adequately from the shoulder of the prosthesis or the calcar region adjacent to the prosthesis. Occasionally, proximal fitting prostheses may also exhibit bone ongrowth onto the distal titanium portion of the stem, making removal very challenging without the use of an ETO.

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FIGURE 5-1 Anteroposterior (AP) hip radiographs of a 58-year-old female with proximal varus femoral remodeling who underwent reimplantation after infected THA. An ETO could have prevented the stem from being placed into a varus position.

Indications also include removal of cement following extraction of a cemented femoral stem, removal of a well-fixed stem in the setting of periprosthetic infection, treatment of periprosthetic femur fractures treated with femoral component revision, and directly accessing the diaphysis for reconstruction in the setting of proximal varus femoral remodeling where stem placement without an ETO may fracture the greater trochanter or result in varus stem position (6,7,8). Figure 5-1 demonstrates the radiographs of a patient who underwent revision THA after periprosthetic infection. Using an ETO could have prevented the revision stem from being placed into varus. When compared with more limited approaches, the ETO has a lower rate of femoral (shaft) fracture, inadvertent femoral perforation, and cement retention (9).

In cases of complex primary THA, the ETO can also be performed prophylactically in cases with significant proximal femoral deformity allowing for protection of the greater trochanter in a controlled manner. In addition, more enhanced acetabular exposure can be obtained in both the primary and revision setting with an ETO (10).

Relative contraindications to use of an ETO include severe osteolysis of the proximal femur and implantation of a cemented stem, whether or not it is in conjunction with impaction grafting. Limited clinical data suggest a higher nonunion rate in patients who undergo impaction grafting after ETO, secondary to cement extrusion at the osteotomy site preventing bony union (11).

 

PREOPERATIVE PLANNING

Preoperative planning is essential for successful outcomes in both the setting of primary and revision THA. The surgeon should include as part of the preoperative plan the likelihood of requiring an ETO and at what step of the procedure it will be performed (before or after hip dislocation). If an osteotomy is planned as part of the

 

operative procedure, the length of the osteotomy must be carefully predetermined. There are conflicting goals to be considered when planning the length of the osteotomy. The goal should be to select an osteotomy length that allows for adequate visualization and performance of the task at the hand (e.g., removal of a well-extensively porous-coated stem) while at the same time leaving enough intact diaphysis for stem fixation. The chosen length of the osteotomy should render at least 4 to 6 cm of isthmic diaphyseal fit for the revision femoral component chosen for reconstruction especially if the revising stem planned is an extensively

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porous-coated cylindrical distal body stem. Tapered distal body revision stems require less diaphysis for fixation

(12). The osteotomy length is usually at least 10 cm long, with most femoral revision osteotomies measuring between 12 and 15 cm in length (13). The length of the osteotomy should be measured from the tip of the greater trochanter. The osteotomized fragment should be long enough to provide enough distance over which two cerclage cables can be utilized for fixation (Fig. 5-2).

While most osteotomies are performed following THA dislocation, patients with periprosthetic fractures, femoral component subsidence, or significant heterotopic ossification about the proximal femur may benefit from undergoing the osteotomy prior to dislocation. The osteotomy can be performed either before or after stem removal. While it is technically most facile to perform the ETO after the stem has been removed, it is often not possible if the component is well fixed.

 

 

 

FIGURE 5-2 A: Preoperative AP hip radiograph of a 59-year-old female with a fractured femoral stem. B: The length of the ETO was planned to be 15 cm preoperatively (C) resulting in greater than 4 cm of diaphyseal fit and allowing for three cerclage cables for osteotomy fixation.

 

 

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SURGICAL TECHNIQUE

Prepping, Draping, and Patient Positioning

Most commonly, preoperative general anesthesia is administered for these procedures since they can be lengthy in nature. A Foley catheter is placed prior to final patient positioning. Patients undergoing an ETO are typically placed in the lateral decubitus position in order to access the hip through a posterior approach. However, an ETO through an anterolateral approach has also been described (14).

A series of positioners are used to maintain the patient's lateral position, making sure to keep the pelvis level, without excessive flexion or extension and without excessive anterior or posterior rotation. Foam padding is placed under the down leg to protect all bony prominences (fibular head and lateral malleolus), and the down leg

should be taped down in order to use the heels and the knees as a reference for leg length following reconstruction (Fig. 5-3). The operative limb is elevated and held in position until it is properly prepped with a soap solution and then with chlorhexidine.

Following sterile prepping, the operative limb is draped in standard fashion using a series of stockinettes, Cobaan, U-drapes, and sterile hip drapes, making sure to leave a widely prepped area to allow for adequate surgical exposure. Iodine-impregnated sheets (Ioban) are typically used to cover the exposed skin of the operative hip making sure to avoid any exposed skin while mobilizing the limb during the procedure.

 

 

 

FIGURE 5-3 Positioning of a patient prior to ETO. The patient should be placed in the lateral decubitus position with the operative side exposed. The contra-lateral leg is taped down to be used for reference for leg length measurements.

 

Surgical Approach—Posterior Approach

 

An incision is marked out over the posterior one-third of the greater trochanter with a slight posterior curve as it extends proximally beyond the tip of the greater trochanter (Fig. 5-4). A previous incision may be incorporated; however, a new incision can be made if necessary without compromising the blood supply to the soft tissue sleeve due to vascular redundancy and robust anastomoses surrounding the hip. Sharp dissection is taken down to the fascia, and a fascial incision is made in line with fibers of the fascia and the underlying gluteus maximus. A Charnley retractor is placed making sure that the posterior blade is not too deep, which may put the sciatic nerve at risk of injury. The gluteus maximus femoral insertion is identified (Fig. 5-5) and recessed in the setting of revision THA to minimize posterior tethering of the femur. A posterior capsular approach is performed following the posterior border of the vastus lateralis and the posterior border of the gluteus medius, along the capsular and short external rotator attachment to the posterior greater trochanter/piriformis fossa (Fig. 5-6). The capsule is tagged with a series of no. 5 caliber suture (e.g., Ethibond). The hip is dislocated in a controlled manner using a bone hook after adequate scar excision has been performed.

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FIGURE 5-4 Posterior incision for exposure prior to an ETO.

 

 

 

FIGURE 5-5 It is necessary to recess the femoral insertion of the gluteus maximus to enhance surgical exposure when performing an ETO and minimize posterior tethering of the femur.

 

 

 

FIGURE 5-6 During the posterior approach to the revision hip, it is important to clearly identify the posterior borders of the vastus lateralis and the abductor complex in order to properly position the capsular incision.

 

 

 

Femoral Exposure

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The leg is placed in an extended and internally rotated position to allow for easy placement of a proximal femoral elevator under the calcar for exposure. The limb is now flexed and internally rotated for visualization of the shoulder of the proximal femur. The skin incision at this time is extended distally to accommodate the length of the preoperatively planned osteotomy. The posterior border of the vastus lateralis is detached from the lateral intermuscular septum, and care is taken to systematically cauterize all perforators of the profunda femoris to minimize blood loss.

Two blunt Hohmann retractors are placed under the vastus lateralis and held against the anterior cortex of the femur. The vastus lateralis attachment is maintained at the vastus ridge along with the proximal abductor complex attachment. It is important to maintain the entire sleeve of tissue in continuity so as to not disrupt the blood supply to the lateral femur.

 

Performing the Extended Trochanteric Osteotomy

 

A ruler is used to mark out the preoperative planned distance of the osteotomy from the tip of the greater trochanter. A pencil-tip burr on a high-speed drill is then used to make the transverse limb of the ETO extending approximately one-third of the diameter of the femoral shaft. The burr is then used to make rounded corners of the osteotomy extending approximately 1 cm at both the anterior and posterior margins of the osteotomy (Fig. 5-7). A microsagittal or standard oscillating saw blade is then used to extend the posterior limb proximally the entire length of the osteotomy (Fig. 5-8).

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Placing the leg in extension and internal rotation, while performing the posterior limb of the osteotomy, will allow for proper visualization of the posterior aspect of the femur.

 

 

 

FIGURE 5-7 A pencil-tip burr is used to start the posterior proximal limb of the osteotomy.

 

 

 

FIGURE 5-8 The posterior limb is extended distally with the use of a microsagittal saw.

 

The limb is then placed in external rotation, and the pseudocapsule at the anterior corner of the greater trochanter is released using electrocautery. Release of this tissue allows adequate visualization to perform the proximal anterior limb of the osteotomy over short distance (1 cm). In addition, release of the tissue allows for the osteotomy fragment to be returned to its original position during repair of the osteotomy. If this tissue is not adequately released, then the limb is typically placed in abduction and excessive internal rotation in order for reduction of the osteotomy fragment, resulting in unnecessary tension and higher risk for fracture or fragmentation of the osteotomy fragment.

Once the entire posterior limb and short segment of the anterior limb of the osteotomy have been achieved, the remainder of the osteotomy can be completed. A series of broad, flat osteotomes are placed from posterior to anterior along the length of the posterior limb of the ETO (Fig. 5-9). The limb should be placed in internal rotation during this portion of the procedure. The osteotomes are used to complete the osteotomy by lifting simultaneously and “cracking” the osteotomy; this results in a controlled greenstick fracture of the remaining anterior limb of the osteotomy. The soft tissue remains attached to the femur throughout the entire procedure.

The Charnley retractor is repositioned at this point to include the osteotomy fragment (Fig. 5-10).

 

 

 

FIGURE 5-9 The ETO is completed using a series of osteotomes to open the osteotomy from the posterior aspect of the femur.

 

 

 

FIGURE 5-10 A completed ETO with the fragment now secured by the anterior blade of the Charnley retractor.

 

 

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FIGURE 5-11 A prophylactic cable should be placed circumferentially around the femoral shaft approximately 1 cm distal to the distal extent of the osteotomy. This cable must be placed prior to any broaching or reaming of the femoral canal.

 

Once the osteotomy has been completed, we place a prophylactic cable circumferentially around the femoral shaft approximately 1 cm distal to the extent of the osteotomy (Fig. 5-11). The cable helps to prevent propagation of the osteotomy into an uncontrolled femoral shaft fracture. The prophylactic cable should be placed prior to any reaming of the distal femoral canal.

 

Repairing the Extended Trochanteric Osteotomy

Once the femoral reconstruction has been completed, the osteotomy fragment can be restored to its original position for repair. The operative limb is placed on a padded mayo stand and placed in a position of neutral abduction and slight internal rotation. Approximately two to three cables are used for repairing the osteotomy. All of the cables are placed circumferentially around the proximal femur using a cable passer; each cable should be

passed deep to the vastus lateralis. A pointed fracture reduction clamp is then used to place the osteotomy fragment in its original position. The reduction does not need to be anatomic, however.

Often, the stem used for femoral reconstruction is too bulky to accommodate the remaining cancellous bone stock of the greater trochanter. Without removal of a portion of this bone stock, adequate reduction of the osteotomy fragment is often not possible. A high-speed burr is used to remove the appropriate amount of cancellous bone from the greater trochanter. This step takes a few iterations in order to adequately debulk the greater trochanter and allow for fragment reduction. Great care must be taken to only remove the bone needed for fragment reduction; excessive bone removal can result in greater trochanter fracture or further fragmentation. If a cement mantle remains from a prior cemented THA, it is not always necessary to remove the cement, as it can strengthen the osteotomy in the setting of proximal femoral osteolysis.

The most distal and most proximal cables are sequentially tightened until the desired tension has been reached. Each cable is then crimped and cut; the middle cable is tensioned and prepared in a similar fashion. It is important to ensure that each cable is placed distal to the lesser trochanter if possible; the lesser trochanter prevents proximal migration of the cable in the event of cable or osteotomy fragment failure. Allograft strut grafts may be used to augment fixation in the osteolytic femurs where the struts help distribute forces with cables. At the conclusion of securing the cables, the femur should move as a single unit.

 

Postoperative Rehabilitation Protocol

Patients are typically placed in a postoperative hip brace with no active abduction for 6 weeks. The use of a brace following revision THA has not been shown to prevent dislocation (15); however, the presence of a brace reminds the patient of his or her precautions as well as alerts staff at a rehabilitation facility to exercise care when treating the patient. Avoiding active abduction is a critical part of the postoperative protocol in order to minimize the risk of ETO fragment migration; due to traction of the abductor insertion, the greater trochanter fragment has a tendency to escape proximally and abduct with anterior rotation.

 

The patient is made touchdown weight bearing for a period of at least 6 weeks in order to minimize joint reaction force across the hip and optimize the mechanical environment for biologic fixation of the femoral stem. Weight-bearing status can usually be advanced at the 6- to 8-week

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point, assuming no interval change in the position of the components based on x-ray evaluation. Figure 5-12 demonstrates a patient with subsidence of the femoral stem and proximal trochanteric escape with associated total hip dislocation.

 

 

 

FIGURE 5-12 A: Postoperative AP hip radiographs of an 84-year-old female following femoral component revision. B: AP hip radiograph demonstrating femoral component subsidence and proximal trochanteric escape resulting in THA dislocation 6 weeks after surgery.

 

Summary of Clinical Results The ETO has been shown to have high union rates with good clinical results in both revision and complex primary THA, with rates of nonunion of less than 2% reported in the literature (2,3,5,16). Union rates are summarized in Table 5-1. Miner et al. (3) reported a nonunion rate of only 1.2% in a large series of 166 revision THAs at minimum of 2-year follow-up. Based on the Merle d'Aubigné and Postel scale, patients' pain and walking scores improved from a mean of 6.5 (range 1 to 10) preoperatively to a mean of 9.8 (range 4 to 12) postoperatively following revision THA with use of an ETO (3). Mardones et al. (16) reported similar results in their series of 74 patients, with only 1 patient going on to nonunion. They did have five cases of less than 5-mm proximal migration of the osteotomy fragment.
	TABLE 5-1 Summary of Published Union Rates following ETO
			Younger et al. (2)	Miner et al. (3)	Chen et al. (5)	Mardones et al. (16)
		No. of patients	20	166	46	74
		Mean followup	18 mo	45 mo	44 mo	24 mo

% Union

100%

98.8%

98%

98.6%

Complications

1 case of

malunion

2 trochanter fractures treated

nonoperatively

5 cases <5-mm

migration

 

 

 

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FIGURE 5-13 AP (A) and lateral (B) preoperative radiographs of a patient who had previously undergone a resection arthroplasty with placement of an articulating antibiotic spacer. C: The patient underwent successful reimplantation of revision THA components with an ETO to address proximal varus femoral remodeling.

ETO also demonstrates predictable postoperative healing and excellent functional outcomes in the setting of periprosthetic fracture. Figure 5-13 demonstrates the preoperative and postoperative radiographs of a patient who underwent successful ETO. Levine et al. (6) reported a series of 14 patients with Vancouver B2/B3 periprosthetic fractures treated with revision THA and ETO at minimum 2-year follow-up. All patients healed the osteotomy site with osseointegration of the femoral component and mean postoperative d'Aubigné and Postel scores of 8.6.

Some surgeons worry about the use of ETO in the setting of periprosthetic infection due to the concern for potential poor osteotomy healing in the setting of infection. Lim et al. published a small comparative series comparing patients who underwent ETO for two-stage revision for infected THA and those revised for

aseptic loosening. There was no difference in postoperative Harris hip scores, union rate, or time to union

between the groups (17). Levine et al. found that 22 out of 23 patients healed their ETO in the setting of stem removal for periprosthetic infection at a mean of 11.5 weeks, with 20 of these patients eradicating the infection. ETO is a useful tool not only for removing well-fixed femoral implants but for management of periprosthetic infections and fractures as well (8).

 

 

 

 

COMPLICATIONS

While the ETO has produced excellent results in achieving union, complications can occur and must be addressed. Intraoperative or postoperative fractures of the osteotomy fragment can occur. Most fractures through an ETO occur at the base of the greater trochanter just proximal to the vastus ridge. Fixation of these fractures typically requires the use of trochanteric claw plate or a series of wires to reduce the fragment and prevent repeat displacement. Although fragment migration is much more common with the standard trochanteric and the trochanteric slide osteotomy, proximal migration of the proximal fragment has been reported with an ETO. Migration of greater than 2 cm can lead to considerable abductor weakness, gait alterations, and construct failure (18,19).

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FIGURE 5-14 A: AP hip radiographs of a patient who underwent fixation of a greater trochanter nonunion with wires following an valgus intertrochanteric osteotomy. B: Follow-up AP hip radiographs demonstrate proximal migration of her trochanteric fragment sustained due to a motor vehicle collision. This was managed conservatively, and the patient is able to ambulate unassisted with the absence of a Trendelenburg gait.

Radiographs of any patient with evidence of construct failure or nonunion should be carefully scrutinized for proximal migration of the osteotomy fragment. In addition to standard posterior hip precautions, patients

should avoid active hip abduction for an additional 6 weeks, but the effectiveness of these “trochanteric

precautions” has yet to be proven. Figure 5-14 demonstrates a patient who had proximal migration of his or her trochanteric nonunion treated with wires and subsequently developed proximal migration of his or her trochanteric fragment. He or she was treated conservatively with no active abduction for 6 weeks. Early migration should be managed with revision fixation with a stronger cable grip construct, especially if THA instability ensues (20). Asymptomatic nonunions without proximal migration can be managed conservatively and followed with serial radiographs. Proximally migrated trochanteric fragments may be treated conservatively if there is an absence of THA instability and the patient exhibits minimal abductor weakness. In these cases, continuity of a robust sleeve of tissue (abductor complex and vastus lateralis) may be sufficient to prevent instability. Surgery should be considered only if the patient becomes symptomatic.

Patients with broken cables may require operative management, even if the osteotomy has healed, since particulate metal debris from the cables can cause polyethylene wear due to third-body wear generation. Prior to repeat surgical treatment, it is imperative to evaluate each individual case and determine the risk/benefit ratio for the intervention, as problems involving the trochanter are difficult to address and may not always render a good clinical outcome.

 

 

REFERENCES

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2. Younger TI, Bradford MS, Magnus RE, et al.: Extended proximal femoral osteotomy: a new technique for femoral revision arthroplasty. J Arthroplasty 10: 329-338, 1995.

    

    

3. Miner TM, Momberger NG, Chong D, et al.: The extended trochanteric osteotomy in revision hip arthroplasty: a critical review of 166 cases at mean 3-year, 9-month follow-up. J Arthroplasty 16(8 Suppl 1): 188-194, 2001.

    

    

4. Della Valle CJ, Berger RA, Rosenberg AG, et al.: Extended trochanteric osteotomy in complex primary total hip arthroplasty: a brief note. J Bone Joint Surg Am 85: 2385-2390, 2003.

    

    

5. Chen WM, McAuley JP, Engh CA, et al.: Extended slide trochanteric osteotomy for revision total hip arthroplasty. J Bone Joint Surg Am 82: 1215-1219, 2000.

    

    

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6. Levine BR, Della Valle CJ, Lewis P, et al.: Extended trochanteric osteotomy for the treatment of Vancouver B2/B3 periprosthetic fractures of the femur. J Arthroplasty 23: 527-533, 2008.

    

    

7. Foran JR, Brown NM, Della Valle CJ, et al.: Prevalence, risk factors, and management of proximal femoral remodeling in revision hip arthroplasty. J Arthroplasty 28(5): 877-881, 2013.

    

    

8. Levine BR, Della Valle CJ, Hamming M, et al.: Use of the extended trochanteric osteotomy in treating prosthetic hip infection. J Arthroplasty 24(1): 49-55, 2009.

    

    

9. Glassman AH: Exposure for revision. Total hip replacement. Clin Orthop Relat Res 420: 39-47, 2004.

    

    

10. Archibeck MJ, Rosenberg AG, Berger RA, et al.: Trochanteric osteotomy and fixation during total hip arthroplasty. J Am Acad Orthop Surg 11: 163-173, 2003.

     

     

11. Hellman EJ, Capello WN, Feinberg JR: Nonunion of extended trochanteric osteotomies in impaction grafting femoral revisions. J Arthroplasty 13: 945-949, 1998.

     

     

12. Weeden SH, Paprosky WG: Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty 17(4 Suppl 1): 134-137, 2002.

     

     

13. Meek RM, Greidanus NV, Garbuz DS, et al.: Extended trochanteric osteotomy: planning, surgical technique, and pitfalls. Instr Course Lect 53: 119-130, 2004.

     

     

14. MacDonald SJ, Cole C, Guerin J, et al.: Extended trochanteric osteotomy via the direct lateral approach in revision hip arthroplasty. Clin Orthop Relat Res 417: 210-216, 2003.

     

     

15. Murray TG, Wetters NG, Moric M, et al.: The use of abduction bracing for the prevention of early postoperative dislocation after revision total hip arthroplasty. J Arthroplasty 27(8 Suppl): 126-129, 2012.

     

     

16. Mardones R, Gonzalez C, Cabanela ME, et al.: Extended femoral osteotomy for revision of hip arthroplasty: results and complications. J Arthroplasty 20: 79-83, 2005.

     

     

17. Lim SJ, Moon YW, Park YS: Is extended trochanteric osteotomy safe for use in 2-stage revision of periprosthetic hip infection? J Arthroplasty 26: 1067-1071, 2011.

     

     

18. Hersh CK, Williams RP, Trick LW, et al.: Comparison of the mechanical performance of trochanteric fixation devices. Clin Orthop Relat Res 329: 317-325, 1996.

     

     

19. Amstutz HC, Maki S: Complications of trochanteric osteotomy in total hip replacement. J Bone Joint Surg Am 60: 214-216, 1978.

     

     

20. Jarit GJ, Sathappan SS, Panchal A, et al.: Fixation systems of greater trochanteric osteotomies: biomechanical and clinical outcomes. J Am Acad Orthop Surg 15(10): 614-624, 2007.