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Tips and Pearls

The Transtrochanteric Approach to the Total Femur Replacement: A Novel Technique

Pennington, Jake DO*; Riggle, Patrick K. DO*; Brazier, Brett G. DO; Cochran, Jason M. DO

Author Information
Techniques in Orthopaedics: March 2020 - Volume 35 - Issue 1 - p 45-48
doi: 10.1097/BTO.0000000000000342
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Abstract

Total femur replacement (TFR) has historically been utilized as a limb salvage technique. Indications for this procedure include primary neoplasm of the femur, extensive metastatic disease, end-stage cases of failed orthopedic implants, failed internal fixation, and severe acute fractures with poor bone stock.1 Initially, the first total femur prostheses were associated with poor outcomes secondary to a high failure rate. These prostheses were equipped without a rotating platform and had a fixed hinge design. With the introduction of modularity in the 1980s, however, more patient-specific implants became available that allowed for a larger range of implant adaptations and improved outcomes.2 Even with the more advanced options in terms of implants and adaptations, it is currently a relatively rare procedure. Because of this, there is still much to be learned with regard to providing good long-term outcomes especially with the increase in total knee arthroplasty which will ultimately lead to more periprosthetic fractures and ultimately more TFR’s.3

In oncological TFR cases, it has been advocated that the surgical technique should be dictated by the anatomy of the tumor.1 In the case of nononcologic TFR secondary to periprosthetic fractures, aseptic loosening or infection, however, there have been many options provided for a surgical approach. These include a direct lateral incision with an anterolateral incision proximally and a separate midline incision distally or a single anterolateral incision.4 Although this patient group has had better outcomes at the 10-year time point,5 there have still been many complications that have been associated with this procedure. Because of the high complication rate, it is important to examine different surgical techniques that allow for a shorter operative time while at the same time limiting complications and providing good long-term outcomes. This is demonstrated by multiple reports of isolated cases examining different surgical techniques.6 The following technique report examines the use of a transtrochanteric approach for a TFR secondary to periprosthetic fracture which yielded no postoperative complications and has had a good outcome 2 years following surgery. The authors of this report realize, however, that this is only one case and that one good outcome cannot necessarily be extrapolated upon. Even with this in mind, because of the rarity and challenge of this procedure, we feel that this successful outcome without complications is a valuable contribution to the discussion on improving the TFR success rate.

TECHNIQUE

The authors of the following technique report have had the patient consent to her data being submitted for publication. In this case, the patient is a 69-year-old woman with a body mass index of 26.7, who had previously undergone a distal femur replacement for a periprosthetic fracture surrounding a revision total knee arthroplasty. The patient subsequently had subsidence of the proximal stem of the distal femur replacement with inadequate bone stock leading to a TFR as the salvage option available (Fig. 1).

FIGURE 1
FIGURE 1:
A, AP radiograph demonstrating a well-fixed distal femur replacement 1-year postoperatively. B, AP radiograph demonstrating implant subsidence and loosening around the cement mantle 3 years postoperatively. AP indicates anteroposterior.

The patient was informed of the complexity of the procedure and after a discussion of the risks and benefits of surgery, the patient elected to proceed with the operation. The patient was taken to the operating room and placed under spinal anesthesia. She was positioned in the lateral position on a standard operating room table with a peg board holder. The left leg was prepped and draped in the standard sterile manner with chlorhexidine scrub. A standard extensile lateral skin incision was made for an adequate approach to the proximal femur as well as to remove the distal femoral implant from the femoral shaft. Dissection was made down through the IT band. When the greater trochanter was encountered, a direct lateral transtrochanteric osteotomy was performed. The osteotomy was vertical in nature and in the coronal plane, leaving adequate bone stock anteriorly and posteriorly to later be repaired. In addition, the anterior and posterior capsular and muscular attachments were maintained to both greater trochanter pieces. The extensile lateral dissection was then continued distally, incising the vastus lateralis and continuing with a standard subvastus exposure.

FIGURE 2
FIGURE 2:
Intraoperative image of the proximal femur removed with the modular component remaining intact in the distal aspect.
FIGURE 3
FIGURE 3:
Intraoperative image of the total femur hemiarthroplasty reduced through the transtrochanteric approach with anterior half of greater trochanter (*) keeping the anterior soft tissue attachments intact and the posterior half of greater trochanter (#) with the abductors and short external rotators intact.

The taper breaker was then utilized to break the taper between the distal femoral replacement and the stem. After a superior capsular arthrotomy, the distal femoral stem along with the proximal femur were removed in its entirety. The proximal femur bone was taken to the back table and templated for trial components (Fig. 2). Using a stryker Global Modular Replacement System (GMRS; Stryker, Kalamazoo, MI), a size of 40-mm head with −4 mm offset, and size 80 metal to metal adaptor was trialed with good stability throughout the range of motion.

These final implants were implanted in the patient without difficulty. The hip was reduced without complications (Fig. 3). The hip and implant were irrigated copiously. The transtrochanteric osteotomy was repaired with three 18-g cerclage cables (Fig. 4). Following this, we proceed to close the IT band, the subcutaneous tissue, and superficial skin. An incisional wound vacuum-assisted closure (VAC) was used to aid in wound healing and reduce perioperative edema.

FIGURE 4
FIGURE 4:
Intraoperative picture showing the application of the cerclage cables to fixate the transtrochanteric osteotomy to the prosthesis.

Postoperative x-rays taken demonstrated no immediate complications. The patient was allowed to weight bear as tolerated on postoperative day 1 and worked with physical therapy twice daily. The patient was discharged home from the hospital on postoperative day 3.

DISCUSSION

As the number of total hip and knee replacements increases every year, so does the burden of revision surgery.5 Because of this increase, thorough knowledge of salvage procedures, such as a revision to TFR, is of increasing importance. Although TFR for oncologic indications is well described and discussed in the literature, the use of TFR for revision surgery is not.

The major pitfalls or complications commonly associated with TFR include instability, gait pattern abnormalities, infection, blood loss, and leg length discrepancy.1–7 Although historically there are many complications associated with this procedure, we are providing pearls for a new transtrochanteric approach to TFR which has yielded a good clinical outcome without any complication.

Pearl 1

The use of the transtrochanteric osteotomy and superior capsulotomy helps maintain the anterior and posterior structures which are critical to the stability of the hip. Other approaches, specifically those for nononcologic TFR, describe the use of an anterolateral approach where the abductors are dissected off their attachment to the greater trochanter. This leaves unreliable tissue reattached to the proximal femur which can cause weakness and gait abnormality. Eventually, with the anterolateral approach, the short external rotators (SERs) and all proximal femur muscular and capsular attachments must be dissected off during the removal of the remaining femur. Amanatullah et al,7 in their retrospective review of 20 TFR in nononcologic patients, revealed that 25% of their patients had issues with instability following TFR surgery. To add to this, 10% were related to primary instability. Our technique, however, maintains the native entheses of the abductors and SERs as well as the capsule to the anterior and posterior greater trochanter pieces that are created when making the vertical osteotomy through the trochanter in the coronal plane. This allows for the potential of bony ingrowth of the greater trochanter pieces onto the grit blasted coating of the proximal femoral segment. If bony ongrowth is obtained, it can potentially instill long-term stability and prevent a trendelenburg gait commonly associated with the traditional anterolateral approach to the hip (Fig. 5).

FIGURE 5
FIGURE 5:
Postoperative anteroposterior radiograph demonstrating the greater trochanteric pieces being reduced by cerclage cables.

Pearl 2

The use of a modular system for revision total knee and hip arthroplasties can be beneficial when converting to TFR. The modularity of the GMRS allowed us to retain distal femur and tibial components, which were well fixed and would have been challenging to remove. This allowed us to perform the revision through a smaller incision which resulted in shorter operative time, less blood loss, and a less extensive dissection. In a minireview of the literature by Ramanathan et al,4 they reported that increased operative time and a more extensive surgical incision are associated with an increased risk of infection, greater blood loss, and more postoperative complications. The modular system, also, allowed for better control of the leg length and easier adjustments intraoperatively to correct for discrepancies that were not accounted for preoperatively.

Pearl 3

A total femur hemiarthroplasty is an option. Historically, a lack of control of femoral anteversion has been thought to increase the risk of hip dislocation leading most surgeons to place an acetabular component with a constrained liner to maintain stability. Our technique, however, demonstrates that you can maintain stability without the use of a constrained liner. Hemiarthroplasties have historically conferred better stability when compared with THA in similar patient populations. With proper technique and maintenance of the entheses of the SERs and abductors, we believe this to be true when performing TFR as well. This also decreases the total surface area of the prosthesis, which has been demonstrated to be an additional risk factor for prosthetic joint infection and further limits TFR complications.4

Pearl 4

VAC systems are helpful to prevent postoperative edema and seroma formation. They seal the incision faster and help prevent the risk of prolonged drainage. It also reduces the need for dressing changes and maintains the sterile environment which aids in healing and helps to prevent complications. We feel that the use of VAC systems are invaluable and are especially useful in the patient population that typically undergoes a revision to a TFR. In our case, we utilized a wound VAC and had no problems associated with wound healing.

CONCLUSIONS

Revision to TFR is a rare surgery and it is fraught with complications. We believe that the pearls presented in this report with regard to our novel technique will help to prevent or, at a minimum, decrease the risk for the most common pitfalls of TFR surgery. Our case shows that you can have a good functional outcome without complication at 2 year follow-up when utilizing the pearls presented in this report.

REFERENCES

1. Ghert MA, Harrelson JM, Scully SP, et al. Total femoral replacement. Operative Tech Orthop. 1999;9:121–127.
2. Kotz R. Megaprothesen: KMFTR® bis GMRS® Megaprostheses: KMFTR to GMRS. Der Orthopäde. 2010;39:922–930.
3. Windhager R, Schreiner M, Staats K, et al. Megaprostheses in the treatment of periprosthetic fractures of the knee joint: indication, technique, results and review of literature. Int Orthop. 2016;40:935–943.
4. Ramanathan D, Siqueira MB, Klika AK, et al. Current concepts in total femoral replacement. World J Orthop. 2015;6:919–926.
5. Clement ND, MacDonald D, Ahmed I, et al. Total femoral replacement for salvage of periprosthetic fractures. Orthopedics. 2014;37:e789–e795.
6. Agrawal A, Agrawal V, Yadav S, et al. A case report of dual incision technique for total femur arthroplasty as a salvage procedure in infected non-unions. J Orthop Case Rep. 2017;7:44–47.
7. Amanatullah DF, Trousdale RT, Hanssen AD, et al. Non-oncologic total femoral arthroplasty: retrospective review. J Arthroplasty. 2014;29:2013–2015.
Keywords:

TFR; transtrochanteric approach; nononcologic TFR

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