Surgical dislocation of the hip was described by Ganz et al. over a decade ago for the treatment of femoroacetabular impingement (FAI) (see also Technique 8 ). The surgery is designed to allow full access to the acetabulum and the femoral head–neck junction while preserving the blood supply to the femoral head. The approach protects the deep branch of the medial circumflex artery as it supplies the posterolateral retinacular vessels to the femoral head. The major advantage of the approach is its extensile nature with full access to the acetabular rim, the labrum, and the femoral head–neck junction without the limitations of arthroscopy and limited anterior approaches. Surgical dislocation of the hip also has been used for open treatment of slipped capital femoral epiphysis and Pipkin fractures of the femoral head. The shortcoming of the approach also relates to its extensile nature, which requires trochanteric osteotomy with a more prolonged recovery compared with more limited exposures.
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With the patient in the lateral decubitus position, make a Kocher-Langenbeck incision and split the fascia lata accordingly ( Figure 6-1 ). Alternatively, make a Gibson approach and retract the gluteus maximus posteriorly.
Figure 6-1
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Internally rotate the leg and identify the posterior border of the gluteus medius. Do not mobilize the gluteus medius or attempt to expose the piriformis tendon.
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Make an incision from the posterosuperior edge of the greater trochanter extending distally to the posterior border of the ridge of the vastus lateralis.
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Use an oscillating saw to make a trochanteric osteotomy with a maximal thickness of 1.5 cm along this line. At its proximal limit, the osteotomy should exit just anterior to the most posterior insertion of the gluteus medius. This preserves and protects the profundus branch of the medial femoral circumflex artery ( Figure 6-2 ).
Figure 6-2
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Release the greater trochanteric fragment along its posterior border to about the middle of the tendon of the gluteus maximus and mobilize it anteriorly with its attached vastus lateralis.
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Release the most posterior fibers of the gluteus medius from the remaining trochanteric base. The osteotomy is correct when only part of the fibers of the tendon of the piriformis have to be released from the trochanteric fragment for further mobilization.
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With the patient’s leg flexed and slightly rotated externally, elevate the vastus lateralis and intermedius from the lateral and anterior aspects of the proximal femur.
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Carefully retract the posterior border of the gluteus medius anterosuperiorly to expose the piriformis tendon.
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Separate the inferior border of the gluteus minimus from the relaxed piriformis and the underlying capsule. Take care to avoid injury to the sciatic nerve, which passes inferior to the piriformis muscle into the pelvis.
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Retract the entire flap, including the gluteus minimus, anteriorly and superiorly to expose the superior capsule. Further flexion and external rotation of the hip makes this step easier ( Figure 6-3 ).
