The Direct Anterior Approach to Hip Reconstruction

SECTION VI Outpatient Arthroplasty and Case Efficiency Using the Direct Anterior Approach 374

one must be careful not to damage the immediately deep iliopsoas tendon. Furthermore, there are vessels just adja cent to the transverse acetabular ligament that if cut tend to retract out of view. Any remaining acetabular labrum and soft tissue in the cotyloid fossa are sharply removed. Acetabular Preparation and Cup Placement The initial reamer is performed with a reamer one size smaller than the templated cup size. This technique improves operating room efficiency and reduces unnec essary dulling and cleaning of reamers. Reaming is then performed under fluoroscopic guidance to allow for appropriate cup depth and position ( Figure 44.7 ). The reamer size can be increased if necessary for better fix ation. Using fluoroscopic guidance, the corresponding sized cup is impacted into place at the desired compo nent alignment. It is important to have a well-centered anteroposterior pelvis image because errors in tilt and rotation will alter your perceived abduction and antever sion of the acetabular component. Screws may be placed in the cup for additional fixation. The final polyethylene liner is then impacted into the cup. Femoral Exposure The femoral hook attachment for the table-mounted femoral elevator is placed around the femur, from lateral to medial, and proximal to the gluteus maximus sling. The nonoperative leg is placed on a padded Mayo stand while the foot of the table is lowered to approximately 45° combined with 15° of Trendelenburg to allow for appropriate hip extension. FIGURE 44.5 The TFL is retracted laterally while the rectus is retracted medially using right-angle retractors. The circumflex ves sels are identified by piercing the deep fascia distally with a tonsil and using blunt finger dissection to split the fascia proximally until resistance is encountered at the level of the circumflex vessels. The vessels are coagulated or ligated. The remaining deep fascia is then divided using electrocautery.

before resection and the blade is positioned directly per pendicular to the neck. The tendency is to drop one’s hand laterally, leaving a residual high posterior neck cut level. Furthermore, ensure the lateral Hohmann retractor is pro tecting the TFL because of the risk of damage from the saw blade excursion during the osteotomy. Once the neck resection level is confirmed, the first of two osteotomies is completed. The low neck cut is performed first because this is the more critical cut, especially at the medial calcar. A second, more proximal osteotomy is then made, and the intervening “napkin ring” of bone is removed using a threaded Steinmann pin. This step allows the head to be removed more easily. The remaining femoral head is then removed using the same technique. Care must be taken to protect the TFL muscle belly both from the retractors during exposure and from the sharp bone edges on the cut surface of the femoral head during extraction. Acetabular Exposure With the femoral head and neck removed, the cobra retractor is placed over the anterior wall of the acetabu lum between the labrum and remaining capsule, retract ing the rectus femoris muscle. The Hohmann retractor is placed superolaterally on the ilium, whereas the two pronged Mueller acetabular retractor is placed inferiorly behind the posterior wall of the acetabulum. The inferior capsule may now be incised to enhance exposure, but FIGURE 44.4 The incision is carried down through the subcutane ous tissue to the fascia covering the TFL, which has a distinguish ing purple hue due to the underlying muscle, as opposed to the whiter fascia covering the sartorius medially. The fascia is incised in line with the incision using blunt finger dissection to separate the muscle from the fascia.

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