ORIF Acetabulum, 1

ORIF Acetabulum, Triradiate approach

50 year old gentleman with multiple right lower extremity injuries from a motorcycle vs truck MVA. We fixed his tibia first supine, then flipped him into the lateral position and fixed his distal femur, then approached his acetabulum. He had a complex 2 column injury that looked initially like a T type fracture because it looked as if part of his ilium was still connected to the acetabulum. Intra-operatively it appeared as if this was not the case.

Surgeon: O’Brien

Positioning: Lateral on Jackson table to allow C-arm access


The triradiate approach is centered on the GT – the Kocher Langenbach approach is posterior, and O’Brien makes his anterior incision almost horizontal at the level of the GT, and then curves it up to the ASIS, rather than cutting straight at the ASIS from the GT. The posterior approach is as for the Kocher Langenbach. The fascia overlying the G. Max is incised, and the G.max is split – not too high, as this dennervates it. The abductors are revealed. The fascia lata is split longitudinally and the dissection is carried bluntly via fingers posteriorly to get into the fat around the sciatic nerve. The nerve is then identified. The piriformis is then identified superior to the nerve. It is followed to its insertion and the tendon is tagged then cut. Then the superior and inferior gemelli muscles are identified. They are identified by looking for the rectangular quadratus femoris, and going proximal to it. The obturator internus tendon lies beneath the gemelli, and is identified by directing your finger down from above the superior gemelli, and up from below the inferior gemelli – you can feel the tendon deep beneath the muscles. This tendon is similarly tagged then cut. The obturator internus is the key to the deep dissection of the posterior column.

The anterior incision is carried through the subcutaneous tissue to the fascia overlying tensor fascia lata. The reason O’Brien carries his incision quite horizontally from the GT is that the incision through the TFL is then more distal and therefore less of the muscle is denervated. The fascia overlying TFL is incised with a knife, and the TFL muscle is then incised with cautery. Make sure you make the fascial incision clean with a knife because it is these edges that are repaired in the end – the muscle does not hold suture.

The fascia deep to TFL is then examined. Look for the ascending branch of the lateral femoral circumflex vessel in this area, between rectus and gluteus medius. The anterior border of gluteus medius must be identified and dissected out so that the abductors may be taken up off the capsule once the trochanter is osteotomized. Watch for bleeding in this area.

The trochanter is osteotomized by making stabs into the soft tissue with the cautery, and directing a 3.2 mm drill through to the medial side to exit just at the level of the lesser trochanter. The holes are drilled parallel to one another and tapped for 6.5 mm cancellous screws. The final step in preparing to take off the trochanter is to go posteriorly and dissect the g.minimus off the capsule. This can be done with mets. Once this layer has been dissected off, a lauer is delivered from posterior to anterior and a Gigli saw is passed. The trochanter is then osteotomized.

With the trochanter off, the abductors are then reflected superiorly. Subperiosteal dissection is carried out to lift the abductors off the outer table of the pelvis. This can be done all the way anteriorly to the ASIS. Similarly, the posterior dissection can be brought right down onto the ischium.

Technical tricks to reduction:

A large hook can be used to pull on the femoral head and apply traction to the head/capsule. An incision can be made in the capsule to look inside the joint and visualize the intra-articular derangement.

If there is a fracture through the iliac wing, screws applied to each side can be inserted and a reduction clamp applied to the screws –

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