Posterior Approach to Acetabulum

Aims

To expose the posterior aspect of the acetabulum

Indications

Posterior lip & column acetabular fractures
Simple transverse fractures

Position

Lateral
If necessary skeletal traction can be used
- Skeletal pin through distal femur
For Transverse fractures
- Use prone position unless strong assistant
- In lateral position gravity causes medialization of femoral head

Landmarks

Greater trochanter
Iliac crest

Incision

Longitudinal incision centred over greater trochanter
Start: just below iliac crest
End: 10 cm below tip of greater trochanter

Internervous Plane

Gluteus maximus split

Superficial Dissection

Deepen the incision through subcutaneous fat
Incise fascia lata in line of skin incision in lower half of wound
Extend this incision superiorly along the anterior border of gluteus maximus
- Being careful to preserve inferior gluteal nerve
Retract the split edges to reveal the piriformis muscle & short ER
- Palpate for sciatic nerve
IR the leg to put the short ER on stretch
Detach these muscles from insertion into femur
- Leaver quadratus femoris intact to protect underlying ascending branch of medial femoral circumflex artery
Exposes hip joint capsule
- Often torn in trauma

Deep Dissection

Posterior lip fractures can now be visualized & fixed
Identify Greater sciatic notch
For further exposure of posterior column
- 1. Elevate gluteus medius & minumus subperiosteally from posterior & lateral ilium
- 2. Perform a osteotomy of greater trochanter
  - Divide GT from posterior to anterior removing a piece of bone 5 cm in size
  - Elevate this bone & attached gluteal muscles anteriorly

Dangers

Nerves
- Sciatic
- Inferior gluteal nerve
Vessels
- Inferior & superior gluteal artery
Heterotropic ossification
- Increased with acetabular fractures & trochanteric osteotomy