Introduction Provides exposure to acetabulum proximal femur Indications THA hip hemiarthroplasty removal of loose bodies dependant drainage of septic hip pedicle bone grafting Associated approaches Kocher-Langenbeck more extensile exposure used for complicated acetabular work same interval as posterior approach to hip incision slightly more anterior over greater trochanter Planes Internervous plane no internervous plane Intermuscular plane gluteus maximus innervated by inferior gluteal nerve muscle split is stopped when first nerve branch to upper part of muscle is encountered Vascular plane superior gluteal artsupplies proximal 1/3 of muscle inferior gluteal artery supplies distal 2/3 of muscle line of fat on surface of gluteus maximus marks interval Preparation Anesthesia general most common Position lateral position indications hip arthroplasty position of choice posterior wall and lip fractures skeletal traction may be used in lateral position advantages allows for femoral head dislocation allows buttock tissue to "fall away" from the field prone position indications transverse fractures of acetabulum Approach Incision make 10 to 15 cm curved incision one inch posterior to posterior edge of greater trochanter (GT) begin 7 cm above and posterior to GT curve posterior to the GT and continue down shaft of femur mini-incision approach shows no long-term benefits to hip function Superficial dissection incise fascia lata to uncover vastus lateralis distally lengthen fascial incision in line with skin incision split fibers of gluteus maximus in proximal incision cauterize vessels during split to avoid excessive blood loss Deep dissection internally rotate the hip to place the short external rotators on stretch place stay suture in piriformis and obturator internus tendon (short external rotators) detach piriformis and obturator internus close to femoral insertion reflect backwards to protect sciatic nerve incise capsule with longitudinal or T-shaped incision dislocate hip with internal rotation after capsulotomy Proximal extension may extend proximal incision towards iliac crest for exposure of ilium Distal extension extend incision distally down line of femur down to level of knee vastus lateralis may either be split or elevated from lateral intermuscular septum Dangers Sciatic nerve location initially located along posterior surface of quadratus femoris muscle quadratus femorus anatomy is constant; rarely damaged in setting of fracture prevention extend hip and flex knee to prevent injury use proper gentle retraction and release short external rotators (obturator internus) posteriorly to protect the sciatic nerve from traction treatment of injury treat injury with observation and use of ankle-foot orthosis prognosis recovery of tibial division is good despite severe initial damage recovery of peroneal division is dependent on severity of initial injury Inferior gluteal artery location leaves pelvis below piriformis treatment of injury if cut and retracts into pelvis, flip patient, open abdomen, and tie off internal iliac artery First perforating branch of profunda femoris at risk during release of gluteus maximus insertion Femoral vessels at risk with failure to protect anterior aspect of the acetabulum with placement of retractors anterior to the iliopsoas muscle Superior gluteal artery and nerve location leaves the pelvis above the piriformis and enters the deep surface of the gluteus medius. Quadratus femoris excessive retraction and injury must be avoided to prevent damage to medial circumflex artery Heterotopic ossification (HO) debride necrotic gluteus minimus muscle to decrease incidence of HO