Posterior Approach to Acetabulum (Kocher-Langenbeck)

The posterior approach to acetabulum or as called (Kocher-Langenbeck approach) gives access to the posterior wall of the acetabulum and its posterior column.

• It also allows direct visualization of the dorsocranial part of the acetabulum, either through the fracture gap or via a capsulotomy.

• Posterior Approach to Acetabulum is used for:

  1. Total hip arthroplasty THA.
  2. Hip hemiarthroplasty.
  3. Removal of loose bodies.
  4. Dependent drainage of septic hip.
  5. Pedicle bone grafting.
  6. Posterior wall fractures.
  7. Posterior column fractures.
  8. Posterior wall and posterior column fractures.
  9. Simple transverse fractures (patient prone:
     • Fractures must be less than 15 days old.
     • Fractures line located at or below acetabular roof.
     • No major anterior displacement.
• The Kocher-Langenbeck approach is the easiest of all acetabular approaches, and extensive blood loss is not usually encountered.

• Lateral position:
  • Posterior wall and lip fractures (can use skeletal traction when using lateral position).
  • Allows for femoral head dislocation.
  • Position of choice for joint arthroplasty.
  • Allows buttock tissue to “fall away” from the field.
• Prone position:
  • For transverse fractures  (flex the knee to prevent stretching of sciatic nerve).
  • Femoral head is maintained in  reduced position throughout procedure.
  • Improves quadrilateral surface access.
  • Improved access to cranial and anterior aspect of posterior wall fractures.

• Landmarks:
  1. The greater trochanter.
• Incision:
  • Longitudinal incision centered over greater trochanter:
    • Start just below iliac crest, lateral to posterior superior iliac crest PSIS.
    • Extend to 10 cm below tip of greater trochanter.

• There is no true internervous plane in the posterior approach to acetabulum.
• The gluteus maximus that is split in the line of its fibers is not significantly denervated because it receives its nerve supply well proximal to the split.

• Through subcutaneous fat.
• Incise fascia lata in lower half of incision.
• Extend proximally along anterior border of gluteus maximus:
  • Split gluteus maximus muscle along avascular plane.
  • Release portion of gluteal sling to aide in anterior retraction of muscle belly.
• Detach short external rotators after tagging:
  • The piriformis should be tagged and released approximately 1.5cm from the tip of the greater trochanter to avoid damaging the blood supply to the femoral head.
    • The piriformis will provide a landmark leading to the greater sciatic notch:
      • The contents of the greater sciatic notch include:
        1. Piriformis muscle.
        2. Superior and inferior gluteal vessels and nerves.
        3. Sciatic and posterior femoral cutaneous nerves.
        4. Internal pudendal vessels.
        5. Nerves to the obturator internus and quadratus femoris.
  • The obturator internus should be tagged 1.5 cm from the greater trochanter and blunt dissection should be used to follow its origin to the lesser sciatic notch.
    • Posterior retraction will protect the sciatic nerve
• Clear abductors and soft tissue to visualize posterior capsule and posterior wall region

• No further dissection is needed in setting of isolated posterior wall fracture.
• Palpable exposure of quadrilateral plate to assess reduction of posterior column accomplished by elevation of obturator internus elevation:
  • Access can be enlarged by release of sacrospinous ligament.
• Hip joint exposure:
  • Perform marginal capsulotomy.
  • Capsular attachments to posterior wall fragments need to be kept intact to prevent devascularization.
  • Femoral traction can allow visualization of intra-articular surface of hip joint.
• Osteotomy of greater trochanter:
  • Extends access along external surface of anterior column.

• Proximal Extension:
  • The posterior approach to acetabulum (Kocher-Langenbeck approach) can be extended distally down to the level of the knee.
  • Either split the vastus lateralis or elevate it from the lateral intermuscular septum to allow exposure of the lateral surface of the entire shaft of the femur.
    
• Distal Extension:
  • The posterior approach to acetabulum  (Kocher-Langenbeck approach) cannot be usefully extended proximally.

• The structures at risk during posterior approach to acetabulum  (Kocher-Langenbeck approach) includes:
  1. Sciatic nerve:
     • Extend hip and flex knee to prevent injury.
     • Minimize chance of injury by using proper gentle retraction and releasing your short external rotators (obturator internus) posteriorly to protect the sciatic nerve from traction.
  2. Inferior gluteal artery.
  3. First perforating branch of profunda femoris.
  4. Femoral vessels.
  5. Superior gluteal artery and nerve.

• Surgical Exposures in Orthopaedics book - 4th Edition
• Campbel's Operative Orthopaedics book 12th