Posterior Hip - Todd Pitts, M.D.
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Posterior Hip

posterior hip

Orthopaedic Surgeon - Todd Pitts, M.D., Abilene, Texas

Orthopaedic surgery residency in San Antonio gave me a vast exposure to the various conditions and treatment methods in orthopaedics. I studied and was taught by the leaders in orthopaedics, literally by the surgeons who write the textbooks that the majority of orthopaedic surgeons in the world use as standards of care.

Overview

The posterior approach to the hip was popularized by Moore in the 1950s.12 A recent survey of surgeons from around the world suggests that the posterior approach is the most common surgical approach used internationally for THAs.4 In Canada, about 36% of arthroplasty surgeons use this approach.14 It provides adequate visualization of both the acetabulum and femur during both reconstructive procedures. The approach spares the abductor muscles during surgical exposure of the acetabulum and femur.12 It also has the benefit of providing an extensile exposure to the femur and acetabulum as required.

Anatomy and technical considerations

Similar to the direct lateral approach, for the posterior approach the patient is placed in the lateral decubitus position. Again, the involved limb is draped freely to facilitate dislocating the hip and to permit maneuverability of the limb to improve visualization throughout the procedure.

The skin incision begins 5 cm distal to the greater trochanter, centred on the femoral diaphysis. The incision continues proximal to the greater trochanter. At that point, it curves toward the posterior superior iliac spine for 6 cm. Alternatively, the incision can continue proximally in line with the femur with the hip flexed to 90° (Fig. 10).

Fig. 10

The skin incision used for a posterior approach to the hip. A curvilinear incision or, alternatively, a straight incision with the hip flexed 90° can be used.

The surgeon then incises the fascia latae overlying the gluteus maximus and bluntly splits the muscle down to the short external rotators (Fig. 11). A Charnley retractor is positioned to retract the gluteus maximus. The sciatic nerve is carefully protected as it travels immediately posterior to the short external rotators. After identification of the piriformis, the short external rotators and piriformis are then tenotomized at their insertion onto the greater trochanter. They are then tagged with a braided suture for identification and repair at the end of the procedure. This will then expose the posterior joint capsule, which is incised to reveal the femoral neck and head. Alternatively, the joint capsule can be incised with the short external rotators in a single layer during tenotomy. The femoral head is then dislocated by internally rotating the hip. A femoral neck osteotomy is then performed using Hohmann retractors anteriorly and posteriorly to protect soft tissues.

Fig. 11

Exposure of the short external rotators during a posterior approach.

Once the osteotomized bone is removed, access is gained to the acetabulum and proximal femur. Careful placement of Hohmann retractors around the acetabulum permits adequate exposure for the reconstruction (Fig. 12). The femur is retracted anteriorly to expose the acetabulum to allow adequate restoration of acetabular anteversion. A posterior retractor or self-retaining retractor can be used to retract the posterior joint capsule to facilitate acetabular visualization. During acetabular preparation, soft tissue landmarks, such as the transverse acetabular ligament, reamer position relative to the floor and cup-positioning guides, are used to verify acetabular version and inclination.

Fig. 12

Retractor placement and acetabular exposure using a posterior approach. The tagging suture helps retract the short external rotators, draping them over the sciatic nerve.

The proximal femur is exposed with the leg internally rotated, flexed and slightly adducted. This places the long axis of the tibia vertically. Blunt bone skids or Hohmann retractors can be used to elevate the femur to improve exposure (Fig. 13). Femoral preparation can then be completed in this position. Following the reconstruction, the short external rotators and posterior capsule are repaired through transosseous bone tunnels in the proximal femur or a direct repair to soft tissues.

Fig. 13

Exposure of the proximal femur using a posterior approach. Note the position of the operative limb, held in position by a surgical assistant. Hohmann retractors or bone skids can help elevate the proximal femur during preparation.
-PubMed.com