11 Posterior Approach to Hip Arthroplasty

10.1055/b-0040-174134

11 Posterior Approach to Hip Arthroplasty

Daniel Kim, Jonathan David Gillig, and G. Daxton Steele

Summary

Performing a total hip arthroplasty can be approached from a variety of surgical planes. The posterior approach has its origins in von Lagenbeck’s description, in 1874, for hip resection and furthermore by Kocher, in 1911, for an approach to the acetabulum. Judet subsequently combined the approaches and later, in 1957, Moore modified the approach for total hip arthroplasties. ¹ Since that modification, the posterior approach to the hip has become the primary workhorse incision for total hip arthroplasty. The posterior approach is now sometimes referred to as the Moore or Southern approach. Its popularity is due to its ease, safety, quick access to the joint, need for only one assistant, and lack of loss of abduction power. Furthermore, this approach provides excellent visualization and is also the most common approach for revision procedures.

11.1 Preop

Preoperative templating for component positioning, size, offset, and bone quality is often performed prior to the date of surgery to ensure proper implants are available.
Lateral positioning on electric or Jackson table. Hold lateral decubitus position with beanbag, pegboard, or Stulberg hip positioner (▶Fig. 11.1).
Axillary roll placed under contralateral axilla to protect the axillary nerve.
Clear positioners or beanbag to allow operative hip flexion to past 90 degrees and full extension for the test of stability interoperatively.
Adequate padding should be placed under shoulders, elbow, knee (peroneal nerve), and ankle. Both hips and knees should be slightly flexed to prevent stretch on sciatic nerve.
Note anterior or posterior roll of pelvis, which can misguide acetabular version if using ground as reference. Lateral iliac wing prominence should be perpendicular to floor.
Spinal anesthesia commonly performed, if used recommend Foley catheter to monitor for urinary retention.

**Fig. 11.1** Patient lateral decubitus positioning options. (a) Patients can be held in position with positioning bed attachments such as the Stulberg positioners. Other options include a pegboard with padded posts or a bean bag. In all positions, an axillary roll is placed to protect contralateral axillary nerve and hips and knees are slightly flexed to reduce sciatic nerve tension with padding of contralateral side. (b) Demonstration of the incision of the posterior approach with the dotted line and the greater trochanter demonstrated by the curved solid line.

11.2 Approach

Mark out the greater trochanter and femoral shaft. The incision should be curvilinear in line with the femur shaft along the posterior 1/3 of its width centered over the greater trochanter. Historically, incisions were 10–15 cm in length; however, new mini-approaches can be smaller. Slightly internally rotate femur 5 degrees, which will help with posterior dissection.
Sharp dissection is made through skin with a scalpel. Bovie or scalpel through subcutaneous fat, using rakes for retraction. Identify iliotibial (IT) band and tensor fascia lata; bovie through IT band longitudinally. More proximally are fibers of gluteus maximus muscle, which can be split bluntly. Beware dissection too far proximal on gluteus maximus, where one can encounter the superior gluteal neurovascular bundle.
A Charnley self-retractor is placed under IT band. Internally rotate the femur by placing foot on elevated padded Mayo stand (or have assistant rotate foot up with knee bent). This will expose the posterior aspect of greater trochanter for further dissection.
Dissect out bursa as needed for visualization. Locate the insertion of gluteus medius on the posterior superior border of the greater trochanter. A tip for identification of this tendon is to palpate the length of the medius distally until a sharp drop off along the insertion on the femur.
Locate piriformis and short external rotators. Piriformis tendon will be most robust of all short external rotators. Beware incisions medial to insertion as sciatic nerve can exit superior, trans, or inferior to piriformis. Bovie the piriformis as close to its insertion as possible while leaving a small cuff of tendon insertion for later repair. Tag the piriformis with a #1 vicryl or other large suture.
Retract the piriformis medially and retract other rotators as necessary to visualize underlying capsule.
Capsulotomy should be performed with bovie, can be done in a variety of fashions. A trap door capsulotomy is done by incising as far anterior as possible along the neck and following the femoral neck and acetabular rim. An H capsulotomy is performed by making an incision anterior to the piriformis minimus internal along the femoral neck followed by anterior and posterior flaps creating an H shape capsulotomy. The posterior flap should be carried along the intertrochanteric line until the lesser trochanter is visualized.
After capsulotomy the hip can be surgically dislocated. The motion for dislocation should be controlled and smooth. The hip is adducted by dropping the operative knee, followed by internal rotation and traction.
A cobra retractor is placed under the femoral neck posteriorly and the femoral neck is cleaned of all soft tissue to allow visualization of the lesser and greater trochanters.
The femoral neck cut is referenced off of greater and lesser trochanters via preoperative planning. The neck should be parallel to the ground prior to sawing which is done by lifting the operative extremity. A saw is used to cut the femoral head and neck. An osteotome, bone hook, or corkscrew can aid removal of the femoral head once cut is completed. Sometimes, the anterior capsule needs to be released to allow this.