Acetabular Exposure and Preparation for Reaming     

- see acetabular component

- Discussion:
    - it is essential to have optimal acetabular exposure;
    - once acetabular exposure is achieved, then note native acetabular anteversion;

- Exposure:
    - for hips w/ severe osteoarthritis (or w/ heavily scarred hips) it may be necessary to fully release the quadratus femoris, and a
           portion of the gluteal sling;
           - because the majority of the maximus inserts into the IT band, there is little consequence of releasing the gluteal sling;
           - amount of gluteus tendon released is dependent upon how easy it is to retract proximal femur anteriorly; 
    - protect the sciatic nerve: 
           - note that hip flexion and knee extension will place the sciatic nerve under tension, and
                     will risk a traction palsy with posterior retraction;
           - hence keep the hip in only slight flexion, and make sure the knee is flexed 90 deg throughout;

- Capsule:

    - see: anterior capsule:
    - it is important to leave the superior half of the anterior capsule intact, inorder to avoid anterior instability;
    - insert a bone hook around the greater trochanter and retract it anteriorly and laterally, which puts
             the anterior capsule on stretch;
    - use heavy Mayo scissors to incise the inferior half of the capsule off of its attachment to the femur;
    - alternatively, use large Kelly clamp to "puncture" and "spread" through the anterior capsule, right off of
             the anterior edge of the acetabulum;
    - only incise enough capsule to allow sufficient anterior translation of the proximal femur so that the acetabulum is exposed;

- Retractors:
    - anterior retractor:
         - place acetabular retractor underneath the "elevated" anterior capsule (and underneath the psoas major tendon,  and on top of the
                  pelvic brim to pull stump of neck anteriorly; 
                  - more proximal placement of the retractor may help avoid injury to the iliac artery (due to protection of the psoas muscle);
         - care must be taken at this stage to avoid vascular injuries;
         - references:
                  - Common femoral artery intimal injury following total hip replacement. A case report and literature review. 
                  - Motor-Evoked Potential Analysis of Femoral Nerve Status During Direct Anterior Approach for Total Hip Arthroplasty

    - postero-inferior rectration:
         - a "sciatic nerve retractor" or a sharp Homan retractor is placed just inferior to the posterior 1/3 of the
                 transverse acetabular ligament;
                 - hence the retractor comes to rest at the posterior ischial surface and superior to the obturator externus groove;
         - in some cases, a second retractor needs to be placed directly inferior to the transverse acetabular ligament;
         - retractors may be placed beneath the Charnley retractor and secured w/ a clamp, which then allows the assistant
                 to handle anterior retractor;
         - if retractor is placed too anteriorly, the retractor may injure the obturator artery;
         - if retractor is placed to posteriorly, the retractor may injure the sciatic nerve;
    - superior rectraction:
         - glutei medius and minimus are distracted anteriorly;
         - they may be restrained by inserting steinmann pin into ilium, 2 cm superior to superior margin of the acetabular labrum;

- Labrum and Transverse Acetabular Ligament:
    - expose bony margins of the rim of acetabulum around it entire circumference to facilitate proper placement of acetabular reaming;
           - anterior osteophytes are removed with a rongeur;
           - superior osteophytes dont require removal because they rarely cause impingement & can augment acetabular coverage of cup;
    - excise the acetabular labrum circumferentially;
    - draw soft tissues into acetabulum and divide them immediately adjacent to acetabular rim (keep knife blade within acetabulum);
    - transverse acetabular ligament:
           - some surgeon will use the perpendicular from the ligament to help align optimal cup anteversion;
           - often hypertrophied or calcified & requires at least partial removal (generally the inner half is release;
           - branches of obturator artery may bleed in this area 
           - if transverse acetabular lig needs transection, then release it in posterior half, so to avoid bleeding from  obturator artery; 
           - dividing the ligament will permit reaming to start inferiorly, which avoids the tendency of the reamer to migrate superiorly;
           - references:
                 - The Transverse Acetabular Ligament: Optimizing Version
                 - The transverse acetabular ligament: an aid to orientation of the acetabular component during primary total hip replacement: a preliminary study of 1000 cases investigating postoperative stability.
                 - The role of the transverse acetabular ligament for acetabular component orientation in total hip replacement: an analysis of acetabular component position and range of movement using navigation software.
                 - Acetabular component positioning using the transverse acetabular ligament: can you find it and does it help?

Extensile triradiate approach for complex acetabular reconstruction in total hip arthroplasty.

False aneurysm of the common femoral artery after total hip arthroplasty. A case report.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, May 16, 2018 9:59 am