Direct Lateral Approach to the Hip




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Chapter Synopsis


The direct lateral or transgluteal approach for total hip arthroplasty (THA) is used by clinicians worldwide. Clinical outcomes and potential complications are similar to those for other surgical approaches to the hip joint.


Important Points





  • Primary and straightforward revision THAs can be accomplished with a direct lateral approach.



Clinical/Surgical Pearls





  • Surgery may be performed with the patient in the supine or lateral position.



  • The posterior capsular tissues are usually preserved.



Clinical/Surgical Pitfalls





  • Limp, heterotopic ossification, and superior gluteal nerve injury are not more common with the direct lateral approach if the soft tissues are handled carefully, the vastus-gluteal flap is firmly reattached, and dissection proximal to the greater trochanter is minimized.





Introduction


The direct lateral approach is a commonly used, versatile surgical approach to the hip joint that has many variations. It was originally described by Bauer and colleagues at the University of Innsbruck and reported in 1979 as the transgluteal approach to the hip joint. It was popularized by Kevin Hardinge of Wrightington Hospital in 1982 as an alternative to Sir John Charnley’s approach for total hip arthroplasty (THA), which used a trochanteric osteotomy. The latter procedure necessitated replacing or advancing the greater trochanter to a suitable bone bed with wires or other devices. Trochanteric osteotomy occasionally leads to complications, including fragmentation of the bone, lateral trochanteric pain, trochanteric migration producing a lurching (Trendelenburg) gait, and instability or dislocation. Many of these complications can be avoided with a meticulously performed direct lateral approach to the hip joint.


The direct lateral approach identifies the anterior hip capsule through a continuous, longitudinal, vastus-gluteal musculotendinous flap that is developed on the anterior aspect of the greater trochanter ( Fig. 50.1 ). Modifications of this surgical approach vary according to how anterior or posterior the surgeon develops the flap in the vastus and gluteal musculature and how much of the greater trochanter is taken (i.e., none, small wafer, or larger chunk) in the midportion to thicken the vastus-gluteal flap ( Fig. 50.2 ).




FIGURE 50.1


An anterior vastus-gluteal musculotendinous flap is developed at the junction of the anterior and middle third of the gluteus medius and vastus lateralis, where they insert onto the greater trochanter. The anterior flap may be composed of soft tissue alone, or small fragments of bone can be taken with the tendon using an osteotome to obtain a thicker flap for later bone-to-bone healing. The superior aspect of the flap should not extend more than 5 cm proximal to the superior tip of the greater trochanter to avoid injuring the superior gluteal nerve.



FIGURE 50.2


The vastus-gluteal musculotendinous flap has been developed further. The hip joint is visualized after opening the anterior hip capsule.




Indications and Contraindications


The direct lateral approach is commonly used for uncomplicated primary THA. This approach can also be used for more straightforward revision THAs (e.g., acetabular liner exchange), in which large exposures of the pelvic wing, acetabular columns, or femoral shaft are unnecessary. In the latter case, a more extensile approach with or without a Charnley-type, sliding, or extended femoral osteotomy is indicated.


The direct lateral approach is particularly useful for reconstructing the hip with mild to moderate acetabular dysplasia and excessive femoral anteversion. In this condition, the femoral head is often subluxated anteriorly already and dislocates easily with mild flexion, external rotation, and adduction.


Contraindications to the direct lateral approach for THA include prior incisions around the hip that make use of the direct lateral approach extremely difficult (e.g., very posterior incision) and the need for a more extensile approach to visualize the acetabular columns or femoral shaft. One group introduced distal extension to this approach through a trochanteric osteotomy for a more extensile exposure.




Equipment


No special equipment is necessary.




Surgical Technique


Several modifications of the direct lateral approach vary in the amount of gluteus medius and vastus musculature that is taken anteriorly with the trochanteric flap and whether only soft tissue, bony spicules, or a more substantial bone wafer is included. If the tendinous insertion or periosteum of the these muscles is thin over the greater trochanter, many surgeons thicken the flap by taking some portion of the anterior bony prominence of the greater trochanter with it.


Anatomy


Several important anatomic points need to be considered when performing this surgical approach. First, the approach should be developed parallel to rather than across muscle fibers to limit injury. Proximal and distal muscle should be gently parted rather than transected. Second, the superior gluteal nerve is at risk if the dissection is carried too far proximally. Although some have described “safe zones” for sparing the superior gluteal nerve while performing the direct lateral approach, every patient has unique anatomy. Most surgeons try to limit the abductor incision to 3 to 5 cm above the superior pole of the greater trochanter. No difference in gait mechanics at 6 weeks postoperatively were reported after THA using the anterolateral, direct lateral, and posterior surgical approaches or at 3 months compared with a minimally invasive anterolateral approach and a standard transgluteal approach. This suggests that commonly used surgical approaches to the hip all have the potential to damage muscle and place traction on the superior gluteal nerve. Third, if the distal end of the dissection is carried deeply and anteriorly, the transverse branch of the lateral femoral circumflex artery can be transected and should be cauterized.


Procedure


The direct lateral approach can be performed with the patient in the supine or lateral decubitus position. The supine position facilitates correct orientation of the acetabular component because the pelvis lies flat on the table. However, the assistant on the opposite side of the operating table across from the surgeon has no view of the surgical procedure. If the patient is in the lateral position, all participants have an excellent view of the operation. However, the pelvis should be secured to the operative table with kidney rests, a peg board, or another stabilizing device.


The longitudinal lateral incision is usually slightly anterior to the midportion of the greater trochanter and slightly oblique, located more posterior proximally and more anterior distally. The fascia lata is incised in the same direction. I place one small Hohmann retractor through the gluteus medius tendon just anterior to the superior pole of the greater trochanter and a second Hohmann retractor just distal to the greater trochanter through the anterior vastus musculature. Electrocautery is used to connect the positions of the two retractors, making a shallow U outlining the anterior tubercle of the greater trochanter. If the conjoint tendon over the anterior tubercle is thick, sharp dissection is performed to join the superior and inferior portions of the flap. If this tendon or periosteal insertion is very thin, I use an osteotome to thicken this layer with thin flakes of bone, much like decorticating a bony surface.


The dissection proceeds from either end of the flap into the middle portion. The pericapsular fat is visualized, at which point a knife frees the flap from the capsule, proceeding distally to proximally. Occasionally, the anterior fibers of the gluteus minimus are released. Hohmann retractors are placed over the anterior lip of the acetabulum and above and below the femoral neck.


The capsule and labrum are usually excised, and the hip is dislocated with a bone hook. Flexing, adducting, and externally rotating the leg facilitates this maneuver. The limb is placed in a sterile bag attached to the front of the table. The hip replacement is performed in routine fashion. After reduction of the final components, the vastus-gluteal flap is reapproximated or may be advanced as necessary to tighten the tissues. I sew the distal soft tissue portion of the flap first with size 1 resorbable suture. The bone portion is reapproximated using drill holes through the remaining greater trochanter using size 2 resorbable suture, as is the proximal abductor tendon but not the abductor muscle. Other methods of closure of this layer have been used, including suture anchors and wires. The remainder of the closure is routine.


The overall approach can be miniaturized to fit the patient’s body habitus. However, clear visualization of bony landmarks for appropriate implant positioning and careful soft tissue protection without excessive retraction are essential.

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May 29, 2019 | Posted by in ORTHOPEDIC | Comments Off on Direct Lateral Approach to the Hip
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