Hip Arthrodesis

INTRODUCTION

The average age of patients presenting with symptomatic coxarthrosis is decreasing (1). Excellent medium- to long-term results can be predictably achieved in such patients with total hip arthroplasty (THA). The results of THA in young, active patients (less than 50 years old) are less predictable. Failure rates in this group have been reported as higher (2,3), and risks particular to arthroplasty such as dislocation, osteolysis, and soft tissue reactions to wear particles (adverse reaction to metal debris) are genuine concerns. These results are expected to improve with newer techniques and technology.

The surgeon thus needs to consider all available options in this patient population, which would allow return to an active, productive, and independent lifestyle while delaying their need for a THA. Nonsurgical treatment in this group often fails to address the cause of their symptoms and can sentence them to an increasingly dependent and sedentary lifestyle with resultant health and socioeconomic consequences.

When too late for joint-preserving intervention, such as arthroscopy or osteoplasty, the remaining surgical options in this group include arthrodesis, realignment pelvic or femoral osteotomies, and arthroplasty. Arthrodesis has a definite place in the management of this challenging group especially in the teenage or young adult years

(4). It predictably relieves pain, allows return to daily function including manual work, and can be converted to THA at a later date (5,6). Arthrodesis has been shown to significantly improve quality of life and provide high levels of patient satisfaction (7).

One of the more popular techniques used for hip arthrodesis is that proposed by Duncan et al. (the Vancouver technique) (8). This is in the focus of this chapter. It is associated with a high rate of fusion and usually requires no supplementary immobilization such as a hip spica. The Vancouver technique utilizes a laterally placed “cobra” plate (Fig. 10-1), which facilitates excellent exposure, initial rigid fixation, and reattachment of the greater trochanter over the plate with the attached abductors at their normal length and tension. The trochanter can be mobilized easily at a later date during fusion conversion to a replacement arthroplasty.

INDICATIONS FOR HIP ARTHRODESIS

The ideal candidate is a teenage or young adult male patient involved, or likely to be, in heavy manual labor.

CONTRAINDICATIONS

Contraindications to arthrodesis include the following:

Active infection

Lower back pain or evidence of an abnormality that may become painful (e.g., spondylolisthesis) Ipsilateral knee instability or osteoarthritis

Contralateral hip osteoarthritis

Significant bone loss (absent head and neck) or poor quality such that rigid fixation would be challenging

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FIGURE 10-1 Various sizes of cobra plate used for hip arthrodesis.

PREOPERATIVE ASSESSMENT AND SURGICAL PLANNING

Appropriate patient selection is vital. The most common causes for conversion of arthrodesis to THA include progressive pain in the lumbar spine, ipsilateral knee, and contralateral hip (9). As a result, concurrent degenerative disease in these areas needs to be excluded with a thorough history examination and radiographic evaluation. It is important to accurately measure and document leg lengths and to explain that modest shortening of the limb is to be expected after operation. This is in fact desirable because it facilitates swing through of the foot while walking.

RADIOGRAPHIC EVALUATION

Leg lengths, bone quality, and bone stock of the proximal femur and acetabulum need to be carefully assessed in order to predict intraoperative technical challenges. Poor bone stock on either side of the hip can affect the quality of fixation and fusion rates. A dysmorphic femoral head (secondary to trauma, avascular necrosis, or childhood disease) can result in greater shortening of the limb. Any angular or rotational deformity of the proximal femur must be noted as this can affect the final position of the limb after arthrodesis. This influences the decision as to whether a simultaneous osteotomy is also required.

OPERATIVE DETAILS

The Vancouver Technique

Patient Positioning The patient is positioned in the lateral decubitus position with the affected side up (Fig. 10-2), supported with two deflated beanbags. The lower leg is padded at the knee, lateral malleolus, and dependent chest wall.

FIGURE 10-2 Patient position allowing access to the entire limb.

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The extremity is flexed at the hip to reduce lumbar lordosis. The exact position of the pelvis is ascertained by taking a cross-table lateral AP radiograph and adjusting the position of the pelvis so that the symphysis is lying over the midline of the sacrum. The limb is prepped and draped free (as for a THA). The hip is placed in 20 degrees flexion and 10 degrees adduction. This is deliberate as the compression achieved with the cobra plate will bring it into the required position of neutral duction of the limb (within which the femur remains 5 to 10 degrees adducted—its normal alignment).

Surgical Procedure The skin incision is centered on the middle 1/3 of the greater trochanter. It is curved posteriorly in its proximal extent and follows the line of the femur distally (Fig. 10-3). This is deepened through the subcutaneous fat, and the fascia lata is divided in line with the skin incision. The vastus lateralis is incised and reflected anteriorly (Fig. 10-4). The greater trochanter is then osteotomized and reflected proximally with the abductor attachment (Fig. 10-5), being careful to protect the superior gluteal neurovascular bundle.

An anterior capsulectomy is performed and the hip is dislocated anteriorly. The leg is flexed at the hip and knee and placed in a drape bag over the side of the table. The posterior capsule is left intact in order to preserve the blood supply to the femoral head. The proximal femur is now retracted posteriorly and an uninhibited view of the acetabulum achieved (Fig. 10-6).

FIGURE 10-3 The skin incision, which is centered over the tip of the greater trochanter. It is curved posteriorly in its proximal part.

FIGURE 10-4 The vastus lateralis is incised and retracted anteriorly using Hohmann retractors.

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FIGURE 10-5 A,B: A trochanteric osteotomy is performed and the abductors reflected proximally. C: Depicts the plane of the osteotomy.

FIGURE 10-6 The hip is dislocated anteriorly, an anterior capsulectomy performed, and the leg placed over the opposite side of the table leading to an excellent view of the acetabulum.

An acetabular labrectomy is performed, and the acetabulum is prepared using incremental hemispherical reamers. It is deepened to the medial wall. Attention is then turned to the femoral head. Circumferential osteophytes are removed using rongeurs and osteotomes. The ligamentum teres is excised, and the femoral head is contoured and prepared using female reamers (from the hip resurfacing set) (Fig. 10-7). Preparation in this way facilitates a stable, spherically congruent

fit and maximizes the surface area of bony contact between the femoral head and acetabulum (Fig. 10-8).

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FIGURE 10-7 Acetabular and femoral preparation and the instruments used for preparation. A: Various sizes of reamers. B: Male (right) and female (left) reamers used for preparation of the acetabulum and femoral head, respectively. C1 and C2: Acetabular preparation. D1 and D2: Femoral preparation.

The leg position is carefully adjusted at this stage to the required 20 degrees flexion, 5 degrees external rotation, and 10 degrees adduction (with reference to the pelvis). The femur (not the limb) will therefore be in a position of 20 degrees. The cobra plate is now applied and the proximal compression screw inserted into the roof of the acetabulum (Fig. 10-9). Intraoperative imaging can be used at any point to verify screw, pelvis, and joint position. The compression system is next applied, using a uni- or bicortical more distant screw. Compression of this screw and the first compression screw causes the femur to abduct by approximately 10 degrees and move into the final desired position of neutral abduction/adduction of the limb, within which the femur maintains its normal alignment of slight adduction. This is why we deliberately adduct the limb by 10 to 15 degrees prior to plate insertion. A radiograph is taken at this stage to verify the position of the limb and hardware location. Any adjustments in joint position are made at this stage. If the joint position is satisfactory, the remaining proximal compression screws are inserted followed by the distal screws into the femoral shaft. Cancellous acetabular reamings are used as

autograft. Optimal flexion must be ensured prior to insertion of the proximal screws and rotation optimized prior to insertion of the distal screws.

Next, the greater trochanter is reattached to its normal position with two screws going through the plate and medial cortex. This restores abductor length. Preservation of the abductors is extremely important as injury to these or their nerve supply will compromise the stability of the hip and functional outcome if it is converted to a THA in the future. For this reason, we do not advocate techniques that involve using the iliac crest with its attached abductors as a vascularized bone graft.

In patients in whom the abductors are not violated and optimal alignment is achieved, acceptable functional outcomes and quality of life can be predictably achieved in the long-term postarthrodesis as well as after conversion to THA (7,10). After the plate is applied, a final radiograph is obtained and the wound is closed in layers. Deep drains are not routinely used.

FIGURE 10-8 The prepared femoral head (A) and acetabulum (B). Preparation with matching reamers facilitates a spherically congruent fit with tightly apposed cancellous bone surfaces.

FIGURE 10-9 Application of the cobra plate (A) and the compression device (B).

POSTOPERATIVE CARE

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Feather weight-bearing mobilization is started on day 1 postsurgery. If a drain is used, this is removed 24 to 48 hours post-op.

Partial weight bearing commences at 6 weeks and full weight bearing at 3 months post surgery. Patients are usually discharged at 3 to 5 days. They are placed on an oral anticoagulant for 35 days.

Radiologic signs of bone union are usually seen at 3 to 4 months. A visible joint space, radiolucent lines around the screws, and pain at 6 months or more suggest a nonunion.

If the optimal leg position is achieved and union proceeds without complications, patients can expect complete relief of pain and return to activities of daily living. Patients usually return to work at 6 to 12 months post surgery. Postoperative radiographs several years after successful fusion has been achieved are shown in Figure 10-10.

FIGURE 10-10 Radiographs showing successful fusion.

COMPLICATIONS

Complications occur in 15% to 50% of patients having hip arthrodesis. These include malposition, nonunion, leg length discrepancy, failure to relieve pain, and patient dissatisfaction.

Malposition and nonunion can be minimized by careful preoperative planning and adherence to the surgical technique as well as careful patient selection and preoperative optimization, for example, cessation of smoking.

The later issues can be minimized by clear communication with patients, patient education, and management of their expectations. It is ideal, if possible, for the patient to meet previous patients who have had the procedure and returned to work and daily life.

REFERENCES

1. http://www.njrcentre.org.uk/NjrCentre/Portals/0/Documents/England/Reports/NJR_AR_1.pdf. Accessed

   June 20, 2014.

    

    

2. Sullivan P, MacKenzie J, Callaghan J, et al.: Total hip arthroplasty with cement in patients who are less than 50 years old. J Bone Joint Surg Am 76: 863-872, 1994.

    

    

3. Crawford RW, Murray DW: Total hip replacement: indications for surgery and risk factors for failure. Ann Rheum Dis 56(8): 455-457, 1997.

    

    

4. Duncan CP, Spangehl M, Beauchamp CP, et al.: Hip arthrodesis: an important option for advanced disease in the young adult. Can J Surg 38(Suppl 1): 39-45, 1995.

    

    

5. Villanueva M, Sobrón FB, Parra J, et al.: Conversion of arthrodesis to total hip arthroplasty: clinical outcome, complications, and prognostic factors of 21 consecutive cases. HSS J 9(2): 138-144, 2013.

    

    

6. Richards C, Duncan C: Conversion of hip Arthrodesis to total hip arthroplasty: survivorship and clinical outcome. J Arthroplasty 26(3): 409-413, 2011.

    

    

7. Fernandez-Fairen M, Murcia-Mazón A, Torres A, et al.: Is total hip arthroplasty after hip arthrodesis as good as primary arthroplasty? Clin Orthop Relat Res 469(7): 1971-1983, 2011.

    

    

8. Beauchamp CP, Duncan CP, McGraw RW: Don't throw away the reamers-a new technique of hip arthrodesis. J Bone Joint Surg Br 67(2): 330, 1985.

    

    

9. Jain S, Giannoudis PV: Arthrodesis of the hip and conversion to total hip arthroplasty: a systematic review.

   J Arthroplasty 28(9): 1596-1602, 2013.

    

    

10. Schafroth MU, Blokzijl RJ, Haverkamp D, et al.: The long-term fate of the hip arthrodesis: does it remain a valid procedure for selected cases in the 21st century? Int Orthop 34(6): 805-810, 2010.