Total Hip Arthroplasty in Patients with Proximal Femoral Deformity

 

 

 

INTRODUCTION

 

Proximal femoral deformity in the patient needing total hip arthroplasty (THA) presents both intellectual and technical challenges for the surgeon. If not optimally addressed, proximal femoral deformity can compromise a THA in three main ways: (a) the deformity can force the surgeon to put the femoral component in a position that is suboptimal for hip biomechanics or that compromises hip stability (Fig. 20-1); (b) the deformity can make it difficult to gain femoral component fixation; and (c) the deformity can increase the risk of complications during femoral preparation and implantation such as bone fracture, canal perforation, or abductor muscle damage.

 

Thus, the triple goals of managing proximal femoral deformity during THA are to optimize hip biomechanics for good function of the arthroplasty and hip stability by choosing the best implant position, size, and design; gain reliable and durable implant fixation by optimizing the same three parameters; and minimize the risk of complications by choosing techniques that protect key structures such as the abductors, greater trochanter, and femoral canal integrity (Fig. 20-2). Not infrequently, the surgeon may need to make compromises between these three goals. For example, the surgeon may choose an implant that has a very high chance of durable fixation but only partially reproduces hip biomechanics.

P.256

 

 

 

FIGURE 20-1 A: Hip radiograph of patient with preoperative intertrochanteric level valgus deformity of proximal femur from previous osteotomy. B: THA performed with early hip technology did not allow for correction of deformity. Femoral component was placed in valgus position leading to less than normal femoral offset and

abnormal hip biomechanics. The femoral component also eventually developed aseptic loosening.

 

 

 

FIGURE 20-2 A: Hip radiograph of patient with proximal femoral deformity. B: THA performed with modular implant, which allowed successful management of femoral angular and rotational abnormalities.

 

 

P.257

 

INDICATIONS

The indications for THA in the presence of femoral deformity are very similar to those for any THA. The patient must have a combination of sufficient pain and/or disability related to the hip joint, in combination with sufficient radiographic joint damage, to justify the operation. The more severe the proximal deformity and the more complex the anticipated reconstruction, the greater the potential risk of complications or suboptimal outcome of the procedure. The patient and the surgeon must jointly factor these added risks into the pros and cons of the operation before making the ultimate decision about whether or not to perform the surgery. This inevitably means the threshold for surgery in terms of symptoms may be higher than in some patients with less deformity and hence less risk. Also the surgeon should try to give the patient a realistic idea of what functional level may be achieved in the setting of the deformity and in consideration of the constellation of factors that influence outcome such as muscle quality and acetabular bone deformity. This is important because in some cases, the anticipated level of function may not be the same as for patients with hip problems of shorter duration and with relatively minimal anatomic and soft tissue abnormalities.

 

 

CONTRAINDICATIONS

The usual contraindications to any THA apply, such as the presence of active local or distant infection, or insufficient symptoms to justify level of risk. Furthermore, in these sometimes very complex cases (as noted above), a surgery may not be indicated if the integrated risk of a serious complication seems prohibitively

 

high compared to realistic and likely benefit.

 

 

PREOPERATIVE PREPARATION

Almost all THA surgery can benefit from careful preoperative planning, but there are a few circumstances in which it is more important—and in which more can be gained—by a systematic, careful, and thoughtful approach, than in THA in the setting of proximal femoral deformity. Likewise, and importantly, lack of preoperative planning in this setting risks real problems of avoidable complications and unanticipated intraoperative conundrums.

Proximal femoral deformities may be categorized by etiology or anatomically, and both classification system methods are useful (1). Understanding the etiology will provide clues to anticipated anatomic bony and soft tissue challenges and also to other important considerations. Classifying by anatomic geometry and location is the key to choosing an optimal implant and choosing and executing an optimal surgical technique (1).

The main etiologies of proximal femoral deformity are posttraumatic, postsurgical, developmental dysplasia, developmental following an insult to growth (such as Legg-Calve-Perthes disease or childhood sepsis), metabolic bone disease, and genetic abnormalities. Many of these etiologies have typical bone deformity patterns of both the acetabulum and femur and also specific considerations that are important for THA. Full accounting of these factors is beyond the scope of this book chapter, and the reader is referred to detailed discussions of THA for each diagnosis in this book or other sources. Nevertheless, it is worthwhile pointing out a few important considerations about several of these diagnoses. Deformity secondary to trauma or surgery can take on infinite anatomic variations, but in many cases, retained hardware will be present after previous procedures. Considering what hardware needs to be removed, how it will be removed, and what bone deficiency will be present after removal are all important. Ruling out infection after previous operative treatment or a known episode of previous infection also is important. Patients with hip dysplasia and other developmental abnormalities of the femur related to previous vascular injury or sepsis often have abnormalities of femoral version and associated acetabular deformities. Patients with musculoskeletal genetic disorders often have very abnormal bone size and unusual bone shapes. Patients with metabolic bone disease frequently have very abnormal bone density and may be at risk for bone stress fractures.

Anatomic classification of femoral deformity includes deformity of the greater trochanter, femoral neck, intertrochanteric area, subtrochanteric area, and femoral diaphysis. In each area, deformity may be angular, rotational, or one of bone diameter or length. Fully understanding the anatomy of the deformity is the first element in deciding how best to treat the deformity during THA.

 

Greater Trochanteric Deformity

 

When the greater trochanteric is lateralized, specialized treatment is rarely needed. When the greater trochanter overhangs the femoral canal, the surgeon needs to determine whether it is still possible to place a femoral component without severely damaging abductor attachments. If bone preparation for, and placement of, a standard implant will compromise the greater trochanter, the surgeon may use an implant that can be placed with instrumentation that accommodates the deformity. An alternative is to perform a greater trochanteric osteotomy to safely elevate the greater trochanter,

P.258

place the implant, then reattach the greater trochanter (Fig. 20-3). Methods of greater trochanteric osteotomy and reattachment are described in Chapters 4 and 5.

 

 

 

FIGURE 20-3 A: Hip radiograph of patient with complex proximal femoral deformity and greater trochanter overhanging the femoral canal. B: THA performed with extended greater trochanteric osteotomy to allow implantation of femoral component in optimal alignment without damage to abductor mechanism.

 

Femoral Neck Deformity

Minor femoral neck deformities may require a little deviation from standard THA techniques, but substantial deformities often require a change from either the surgeon's standard implant or technique. Notable deformities of femoral neck anteversion, if not optimally managed, can lead the surgeon to place the implant in suboptimal rotation, which can lead to hip instability or suboptimal hip range of motion (e.g., excessive femoral anteversion can lead to an internal rotation gait and compromise hip external rotation). The most common methods of managing abnormal femoral neck anteversion are to (a) use a cemented component that allows adjustment within the confines of the proximal femur; (b) use an uncemented implant that has little metaphyseal flare and gets fixation in the diaphysis thereby bypassing the area of deformity; or (c) using modular uncemented implants that allow the stem to be placed in optimal anteversion even if fixation follows the anatomic shape of the femur (such as with modular proximal sleeves) (Fig. 20-4).

 

Abnormalities in femoral neck length or angle create challenges in reconstituting leg length and offset. First, the surgeon must decide if it is possible—or desirable—to try to reconstruct the hip to fully “normalize” hip biomechanics. This can be determined on preoperative template taking into account factors such as achievable leg length and desirable femoral offset. If the femoral neck is short, the surgeon may wish to gain some leg length and offset to optimize leg length, hip stability, and abductor lever arm. The amount of the increase in leg length and offset may be constrained by the soft tissue compliance and the amount of tension expected in the sciatic nerve.

P.259

 

 

 

FIGURE 20-4 A: Hip radiograph of patient with proximal femoral deformity with excess anteversion and valgus alignment of femoral neck. B: THA performed with modular implant to manage rotational and angular deformity of femoral neck.

 

Intertrochanteric Deformity

 

Intertrochanteric area deformities create two main considerations: (a) how to obtain optimal femoral component fixation while maintaining good implant position and (b) how to manage the greater trochanter if it overhangs the femoral canal. If a cemented implant will be used, the deformity may be ignored or bypassed (Figs. 20-5 and 20-6). If an uncemented implant is used, the surgeon needs to determine if the deformity is sufficient to require the use of a special implant. Minor deformities

P.260

often may be handled with standard tapered implant designs. More notable deformities may be treated with implants that either bypass the deformity and gain fixation in normal diaphysis or provide for enhanced fixation in the metaphyseal area (such as in modular implants). Angular or rotational femoral osteotomies are rarely needed to accommodate intertrochanteric level deformities. Furthermore, osteotomies at this level leave small proximal fragments of bone, which are at risk for devascularization, fracture, and problems with bone fixation.

 

 

 

FIGURE 20-5 A: Hip radiograph of patient with angular intertrochanteric level proximal femoral deformity due to previous fracture. B: THA performed with cemented femoral component to manage deformity. The cemented stem allowed good implant alignment despite bone deformity.

 

 

 

FIGURE 20-6 A: Hip radiograph of patient with predominantly intertrochanteric level proximal femoral deformity due to multiple familial exostoses. B: THA performed with cemented femoral component that allowed for good implant fixation despite the deformity.

 

Subtrochanteric Level Deformity

Deformities in this anatomic location are typically the most difficult to manage: most are too proximal to ignore but

 

too distal to excise or treat solely with a special implant. In certain cases, the surgeon may choose to employ a femoral implant that is fixed proximal to the deformity and does not extend to the deformity. Such implants would include resurfacing implants or very short-stemmed femoral implants. Each of these implants has specific advantages and disadvantages that require detailed consideration beyond this chapter's scope. Minor deformities of this area occasionally may be treated with standard implants with slight compromise in implant size or position. For the remainder of subtrochanteric deformities, a corrective osteotomy—that adjusts angulation, rotation, length, or a combination of these parameters—is the primary remaining viable method (2,3,4,5,6,7,8,9,10) (Fig. 20-7). Modern methods allow successful anatomy correction and implant and osteotomy fixation during THA and are the subject of the Technique section of this chapter.

P.261

 

 

 

FIGURE 20-7 A: Hip radiograph of patient with subtrochanteric level proximal femoral deformity and a retained intramedullary screw. B: THA performed with corrective angular subtrochanteric level osteotomy and implant that provides fixation proximal and distal to osteotomy. The screw was removed with the osteotomy.

 

Diaphyseal Deformity

Diaphyseal deformities well below the subtrochanteric area usually can be ignored in THA so long as there is sufficient diaphysis above them to accommodate a successful femoral component design (Fig. 20-8).

 

 

 

FIGURE 20-8 A: Hip radiograph of patient with femoral diaphyseal deformity due to previous fracture. B: THA performed with uncemented tapered femoral component. The deformity was sufficiently distal to allow use of a standard length implant.

 

 

 

TECHNIQUE

P.262

The techniques available to manage all the types of deformities discussed above are far too diverse to cover fully in one book chapter. The reader is referred to specific methods in this book (or elsewhere) where techniques are described for specific implants or specific diagnoses (1,11,12,13,14).

This section focuses on the technique of corrective subtrochanteric osteotomy to manage subtrochanteric level proximal femoral deformity. Most previous reports of the technique have focused on its use as a means of managing leg length and rotational abnormalities in patients with high hip dislocation (2,3,4,5,6,7,8,9,10). In this chapter, a more general discussion of the method as it relates to all types of deformities will be included.

Careful preoperative planning is the first step in performing a THA with associated subtrochanteric osteotomy (Figs. 20-9 and 20-10). The surgeon should decide on the proposed level of the osteotomy, and the type of correction (angular, rotational, shortening, or a combination of these). The osteotomy level is chosen based on two factors: (a) the location of the deformity and (b) the need to leave sufficient bone above and below the osteotomy for implant fixation. Naturally, the type of implant the surgeon plans to employ will factor into the proposed osteotomy level. An osteotomy that is too proximal can lead to insufficient bone for a good fixation of the proximal implant or good fixation of the proximal bone (which is needed for osteotomy healing). An osteotomy that is too distal can compromise implant or osteotomy fixation or require use of a femoral implant that is longer than needed.

The surgeon also should use the preoperative planning process to choose an implant design and likely implant size range. The implant can be a cemented or uncemented design (2,3,4,5,6,7,8,9,10), but the author typically

prefers uncemented implants in this setting because they avoid cement extrusion, which can compromise osteotomy healing. Also, many patients with these problems are young, and so the durability of successful uncemented fixation is desirable. An implant should be chosen that will facilitate two simultaneous goals: (a) gain sturdy femoral implant fixation that provides a high likelihood of bone ingrowth into the prosthesis (and can be achieved with implants designed to gain bone ingrowth at the metaphyseal level, diaphyseal level, or both) and

 

(b) gain robust fixation of the

P.263

osteotomy rotationally and with respect to length and angular displacement. Achieving these twin goals typically is accomplished by choosing an implant that fills the metaphysis sufficiently to gain rotational and axial stability of the proximal fragment of the osteotomy and also rotational stability of the distal osteotomy fragment. This typically means implants with a proximal metaphyseal flair and a diaphyseal geometry incorporating flutes, distal porous coating (for a scratch fit), or sharp corners.

 

 

 

FIGURE 20-9 A: Hip radiograph of a patient with subtrochanteric level proximal femoral deformity and intramedullary plate from previous surgery. Preoperative planning performed to correct deformity with wedge osteotomy. B: THA performed with simultaneous corrective subtrochanteric osteotomy.

 

 

 

FIGURE 20-10 A: Radiograph of patient with high hip dysplasia and simultaneous proximal femoral angular subtrochanteric level deformity. Preoperative plan was designed to allow correction of angular deformity and shortening of femur with subtrochanteric level osteotomy. B: THA performed with shortening subtrochanteric osteotomy and acetabular reconstruction at anatomic level.

 

The author prefers a roughly transverse osteotomy configuration because this is technically the simplest and allows for easier angular, rotational, and length adjustment intraoperatively. More complex osteotomy configurations have been described, and most provide enhanced inherent osteotomy stability, but they are technically more complex and usually are not needed with modern implant design and techniques. Implant sizing should be chosen to assure implant fixation, bone fixation, and desired restoration of the joint biomechanics.

Finally, the preoperative plan should include decisions about angular and length correction. Angular correction is straightforward to calculate and should be evaluated on both the AP and lateral radiographs. Length correction is calculated based on preoperative leg length, desired leg length, and the amount of elongation the surgeon estimates the sciatic nerve can safely tolerate.

 

Exposure

 

The hip joint is exposed and the hip is dislocated according to the surgeon's preference. Femoral neck osteotomy is performed at a level based on preoperative plan. The acetabulum is prepared at this point, unless exposure is so difficult that the surgeon prefers to first perform the femoral osteotomy (the typical situation in high hip dislocation). If hardware is present, usually, it is removed after the hip has been dislocated once to reduce risk of fracture from high rotational stresses on the femur during the initial dislocation through stress risers in areas of weakness from recently removed hardware. Next, the femur is exposed in the subtrochanteric area at the level of the proposed osteotomy by making a short longitudinal split in the vastus lateralis. Preoperative planning can provide a measured distance distal to the greater trochanter tip to set the osteotomy level.

P.264

Soft tissues are elevated from the femur anteriorly, posteriorly, and medially for only about 1 cm proximal and distal to the proposed osteotomy, and malleable “ribbon” retractors are placed to protect medial soft tissues. A longitudinal electrocautery mark may be made on the femur to mark starting femoral rotation.

 

Osteotomy

After double checking the osteotomy level, a transverse osteotomy is made. This osteotomy typically is transverse relative to the anticipated alignment of the proximal fragment of bone. A provisional corrective osteotomy (for angle and length) can be performed at this stage. The osteotomy correction typically is subtracted from the distal fragment.

The proximal and distal femoral preparations are performed next. The proximal preparation can be difficult because the bone tends to rotate. Sharp tenaculum locking instruments can be used to grip the proximal bone. The distal femur is prepared with appropriate instruments (typically reamers) to the proper size. Firm engagement of the implant will be needed in the femur; therefore, bone preparation to good cortical engagement is essential.

Prophylactic wires or cables may be passed around the proximal and distal fragments of bone at this time. Trial implants are placed and the hip is reduced. The osteotomy cuts are evaluated and trimmed to provide maximal coaptation. At this point, it is important to assure that both implant and bone rotation (at the osteotomy level) are optimized. Typically, proximal bone rotation is set based on optimizing the rotational alignment of the greater trochanter. The hip is reduced and hip stability is tested and optimized. A radiograph is obtained to check implant sizing and position.

 

Implantation of the Components

If the acetabular component has not been implanted, that is done at this time. Next, the femoral implant is impacted into the femur. Great care is taken to make sure that the implant rotation is correct with respect to the distal femur and that the proximal bone rotation is correct with respect to bony anatomy and the proximal femoral implant. As the femoral component engages the distal femur, the osteotomy may distract and counterpressure on the knee will be needed. As the femoral implant is seated, the osteotomy should close and bone apposition should be good. The implants and osteotomy should be perfectly stable after the implants are completely seated. The hip is reduced, stability confirmed, and appropriate modular head affixed.

Cancellous autogenous bone graft reamings from the acetabulum are packed into any small interstices of the femoral osteotomy and along the small amount of exposed bone proximal and distal to the osteotomy. The vastus lateralis is closed and the remainder of wound closure is routine.

PEARLS AND PITFALLS

 

Perform careful preoperative planning. On preoperative radiographs, measure the level of the osteotomy from the tip of the greater trochanter to the osteotomy level accounting for magnification. Use this measurement intraoperatively to judge appropriate level of the osteotomy.

 

Mark the lateral femur with a vertical electrocautery mark that will cross the proposed osteotomy. This provides guidance about the starting femoral rotation for future reference during the procedure.

 

Cool the bone with irrigation during the osteotomy to keep it healthy. Avoid excess soft tissue stripping on either side of the osteotomy to maintain vascularity.

 

When preparing the proximal femur, pay attention to planned rotation of the implant and the proximal bone fragment. If using a nonmodular implant, remember that this preparation step sets rotation between the implant and the proximal bone fragment.

 

Be careful during trialing to avoid repetitive rotation of the proximal fragment against the trial implant. This can lead to metaphyseal bone loss and destabilize the press fit of the proximal flare of the femoral component, which is needed for osteotomy fixation.

 

Bony fracture during implant seating is not uncommon. Most fractures are small cracks but are best avoided if possible. A complete fracture that destabilizes the proximal fragment is difficult to manage. Use prophylactic cables prior to implantation of the definitive femoral component on both the proximal and distal fragment if bone quality is not excellent.

 

If the implant will be very tight in the distal fragment, very slight overreaming of approximately the proximal 1 cm of the canal of the fragment just distal to the osteotomy may reduce risk of a crack.

 

Optimize osteotomy apposition, with bone fragments properly aligned rotationally using trial implants to judge apposition.

 

 

P.265

 

Make sure both the implant and the proximal bone are properly aligned rotationally, during preparation and implant seating. If using a modular body implant, note that rotation of the implant and proximal bone can occur independently and both must be anatomically optimized.

 

Use autogenous bone graft from the acetabulum to stimulate healing of the osteotomy. This bone is cancellous and typically has good osteogenic potential.

 

POSTOPERATIVE MANAGEMENT

Weight bearing typically is restricted to toe touch to avoid high stresses on the implant for the first 8 weeks after operation. Weight bearing usually is advanced to partial at 8 weeks and then to as tolerated in 12 weeks.

Radiographs typically are taken at 8 and 16 weeks postoperatively. At 8 weeks, the osteotomy usually is not fully healed, but by 16 weeks, it typically has healed.

 

COMPLICATIONS

The main complications related to subtrochanteric osteotomy are osteotomy nonunion and femoral implant loosening. Osteotomy nonunion can be minimized by optimizing bone apposition, cooling the bone during osteotomy with irrigation, and minimizing stripping of muscle. Autogenous bone grafting may also help healing to occur. Finally, making sure the osteotomy is rigidly fixed by the implant is very important. Implant fixation can be optimized by choosing optimally sized implants and gaining rigid fixation.

 

 

RESULTS

There are few case series of THA performed in the presence of proximal femoral deformity, perhaps in part because of the heterogenous nature of these deformities with respect to severity, etiology, and location.

Mortazavi et al. (13) from the Rothman group reported on 58 THAs in hips with proximal femoral deformity treated from 1998 to 2006. Fifty-six hips were treated with uncemented implants. Nonprimary THA implants were used in 25% of femurs, and proximal femoral osteotomy was performed in 23% of femurs. Two hips needed reoperation; one for periprosthetic femur fracture and one for associated femoral component loosening. Radiographically, one femoral component was loose (but not revised) and three had stable fibrous fixation (but were not revised). Overall, they reported a 9% mechanical failure rate of femoral fixation, which is considerably higher than would be expected in routine primary THA. Mean WOMAC scores (a better score is lower) demonstrated substantial improvement from preoperatively to

 

 

postoperatively (14 to 6), and mean Harris hip scores improved from 48 to 87.

Papagelopoulos et al. (14) reported the Mayo Clinic results of THA in 20 primary hips with proximal femoral deformity treated with simultaneous femoral osteotomy from 1969 to 1993, an era before sophisticated uncemented implants that facilitate optimal implant and osteotomy fixation were available. Four of twenty primary THAs treated had femoral revisions by last follow-up. Clinical results at last follow-up were rated excellent in 15%, good in 10%, fair in 50%, and poor in 25%. Eskelinen et al. reported on 68 hips treated with THA along with angular and shortening corrective femoral osteotomy after previous Schanz osteotomy (which creates a large subtrochanteric valgus femoral deformity). At 9 to 18 years postoperatively, 6 CDH type femoral components had been revised, reportedly for technical errors.

Treatment of patients with THA and simultaneous shortening subtrochanteric osteotomy now has been reported in a number of series, mostly in patients with high DDH (in which the osteotomy is primarily performed for femoral shortening and anteversion correction). High rates of osteotomy healing (over 90%) and implant fixation (over 90%) have been reported with use of uncemented implants by most authors (3,5,6,7,8,9,10). With cemented femoral implants, the predictability of osteotomy healing has been less in some but not all reports. Akiyama et al. (2) reported 3 of 15 patients needed reoperation for femoral nonunion in one series. In contrast, Howie reported much more favorable results with union in 32 of 33 hips so treated (4).

 

REFERENCES

1. Berry DJ: Total hip arthroplasty in patients with proximal femoral deformity. Clin Orthop 369: 262-272, 1999.

    

    

2. Akiyama H, Kawanabe K, Yamamoto K, et al.: Cemented total hip arthroplasty with subtrochanteric femoral shortening transverse osteotomy for severely displaced dislocated hips: outcome with a 3- to 10-year followup period. J Orthop Sci 16(3): 270-277, 2011.

    

    

3. Eskelinen A, Remes V, Ylinen P, et al.: Cementless total hip arthroplasty in patients with severely dysplastic hips and a previous Schanz osteotomy of the femur: techniques, pitfalls, and long-term outcome. Acta Orthop 80(3): 263-269, 2009.

    

    

   P.266

    

4. Howie CR, Ohly NE, Miller B: Cemented total hip arthroplasty with subtrochanteric osteotomy in dysplastic hips. Clin Orthop 468(12): 3240-3247, 2010.

    

    

5. Kilicoglu OI, Turker M, Akgul T, et al.: Cementless total hip arthroplasty with modified oblique femoral shortening osteotomy in Crowe type IV congenital hip dislocation. J Arthroplasty 28(1): 117-125, 2013.

    

    

6. Krych AJ, Howard JL, Trousdale RT, et al.: Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia. J Bone Joint Surg 91A(9): 2213-2221, 2009.

    

    

7. Krych AJ, Howard JL, Trousdale RT, et al.: Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia: surgical technique. J Bone Joint Surg 92A(Suppl 1 Pt 2): 176-187, 2010.

    

    

8. Nagoya S, Kaya M, Sasaki M, et al.: Cementless total hip replacement with subtrochanteric femoral shortening for severe developmental dysplasia of the hip. J Bone Joint Surg 91B(9): 1142-1147, 2009.

    

    

9. Onodera S, Majima T, Ito H, et al.: Cementless total hip arthroplasty using the modular S-ROM prosthesis combined with corrective proximal femoral osteotomy. J Arthroplasty 21(5): 664-669, 2006.

    

    

10. Reikeras O, Haaland JE, Lereim P: Femoral shortening in total hip arthroplasty for high developmental dysplasia of the hip. Clin Orthop 468(7): 1949-1955, 2010.

     

     

11. Belzile EL, Laflammes GY: Total hip arthroplasty in proximal femoral deformities and retained hardware.

    Semin Arthroplasty. 19(4): 314-322, 2008.

     

     

12. Goldstein WM, Branson JJ: Modular femoral component for conversion of previous hip surgery in total hip arthroplasty. Orthopedics 28(9 Suppl): s1079-s1084, 2005.

     

     

13. Mortazavi SM, Restrepo C, Kim PJ, et al.: Cementless femoral reconstruction in patients with proximal femoral deformity. J Arthroplasty 26(3): 354-359, 2011.

     

     

14. Papagelopoulos PJ, Trousdale RT, Lewallen DG: Total hip arthroplasty with femoral osteotomy for proximal femoral deformity. Clin Orthop 332: 151-162, 1996.