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Posterior Approach for Acetabular Frx: (Kocher Langenbach)

 - See: Posterior Approach for Pelvic Frx

- Indications for Use:
    - isolated posterior wall & posterior column frxs;
            - allows access to posterior column and posterior wall only, but exposure is limited proximally by
                     superior gluteal vessels and greater trochanter; 
    - isolated transverse frx (as well as associated transverse frxs and posterior wall frx);
    - T shaped fractures (may also use extended iliofemoral approach);

- PreOp Planning:
    - foley catheter;
    - distal femoral traction pin;
    - consider use of EMG w/ needles placed in TA and P longus (asseses peroneal div of
           sciatic nerve) and needles placed in A hallucis and FHL muscles (which are innervated
           by the posterior tibial nerve); 
           - spontaneous EMG allows real time monitoring of potenital sciatic palsy;

- Positioning:
    - options include prone positioning, lateral positioning, or lateral positioning on the fracture table;
    - some surgeons prefer the lateral position for posterior wall fractures and prone position for
              posterior column fractures; 
    - avoid injury to the sciatic nerve;
           - to protect the nerve the knee must be in flexion at all times  

- Exposure:

    - mark out PSIS, sciatic notch, and greater trochanter;
    - incision:
           - incision begins lateral to PSIS, crosses most anterior portion of notch, and subsequently crosses
                  posterior 1/3 of greater tuberosity;
           - incise the skin, subQ tissues, and tensor fascia lata & blunting split the fibers of the maximus;
                  - excessive proximal spliting of the maximus may injure the inferior gluteal nerve;
                  - release a portion of gluteal sling for additional exposure (noting that the major insertion of the maximus is to IT band);
           - trochanteric bursa is incised from distal to proximal, which helps to identify the posterior edge of  gluteus medius and places
                  surgeon at correct plane for identifying the sciatic nerve;
    - sciatic nerve is identified: (see protection of sciatic nerve in THR)
           - at this point, identify: piriformis, quadratus femoris, & sciatic nerve;
           - sciatic nerve is identified on the superficial surface of the quadratus muscle;
           - note any contussions or discolorations of the nerve;
           - to protect the nerve the knee must be in flexion at all times;
           - carefully mobilize the sciatic nerve from its bed of areolar tissue and pass a penrose drain around it for identification;
           - a nerve stimulator may be used to ensure that both divisions of the nerve are contained in the penrose drain;
           - the hip remains extended and the knee flexed through out the procedure inorder to protect the nerve;
    - gluteus maximus split:
           - maximus has dual blood supply which is therefore tolerant of dissection;
           - innervation is derived from inferior gluteal nerve and hence no internervous plane;
           - hence muscle fibers are split up until the first nerve branch to the upper part of the muscle is seen;
           - partially release the release of the gluteus maximus insertion into the femur, which allows adequate posteromedial
                    retraction of the maximus without stretching of the inferior gluteal nerve
    - superior elevation of the medius:
           - identify the interval between the gluteus medius and the piriformis;
           - elevate the gluteus medius (off the pelvis) and retract it superiorly;
           - then drive a large Steiman pin into the ilium at a point well above the acetabulum, which will keep medius retracted
                    superiorly throughout the case;
    - reflect short external rotators:
           - develop plane between the external rotators and underlying hip capsule (w/ periosteal elevator inserted just above
                     piriformis and directed distally);
           - piriformis and the conjoined tendon (gemelli and the obturator internus) are tagged for later repair;
           - be careful not to dissect around or injury the quadratus so as to avoid injury to the MFCA;
           - incise external rotators about 1.5 cm from their insertion points into the greater trochanter inorder to avoid MFCA;
           - reflect short external rotators off of their insertion and reflect them posteriorly inorder to protect the nerve;
           - note that in some cases the external rotators can be partially avulsed from their origin;
    - greater sciatic and lesser sciatic notch:
           - identify the greater and lesser sciatic notch;
           - injury to superior gluteal artery & nerve must be avoided;
           - they can be visualized exiting from greater sciatic notch;
    - exposure of the ilium;
           - exposure of ilium will be limited because superior gluteal artery & nerve enter medius and minimus
                  limiting upward mobilization;
           - elevate the gluteus medius and minimus muscle origins from the external surface of the ilium
           - once the greater sciatic notch is adequately exposed, insert a curved homan retractor;
                  - the reflected external rotators should protect the sciatic nerve from the Homan;
           - a second homan rectrator is placed into the lesser sciatic notch, just below the ischial spine;
                  - take care not to injure the pudenal artery;
                  - this will help retract the conjoined muscles and the sciatic nerve posteriorly;
    - greater trochanteric osteotomy:
           - patients undergoing osteotomy may be at greater risk for heterotopic ossification;
           - sliding osteotomy may be procedure of choice;
                  - this type of osteotomy facilitates visualization of the superior aspect of the hip capsule;
                  - performed correctly, this type of osteotomy should not interfere w/ MFCA and blood supply to the hip;
                  - distal end of trochanter is left attached to the vastus lateralis and the proximal end attached to the
                           gluteus medius and minimus;
           - references:
                  - Osteotomy of the Trochanter in Open Reduction and Internal Fixation of Acetabular Fractures.
                  - Direct complications of trochanteric osteotomy in open reduction and internal fixation of acetabular fractures
                  - Trochanteric flip osteotomy for cranial extension and muscle protection in acetabular fracture fixation using a Kocher-Langenbeck approach
                 - The role of trochanteric flip osteotomy in fixation of certain acetabular fractures.

    - other measures to improve exposure:
           - origin of the hamstrings can be elevated from the ischial tuberosity to expose the lower posterior column;
           - hip capsule can be released from the intact portion of the acetabular rim (perimeter of the labrum);
           - these measures may allow for visualization of the femoral head (after hip dislocation), femoral head debridemont, and
                    management of associated fractures (such as transverse fracture or posterior wall fractures);

- Deep Exposure:
    - exposure of posterior column:
         - entire posterior column of the acetabulum is exposed; using blunt dissection, elevate medius from outer side of ilium;
         - consider femoral distractor:
         - consider trochanteric osteotomy:
                - if visualization of superior dome and anterior column is needed;
                - for difficult transverse or T type frxs;
    - exposure of the posterior wall: (see: posterior wall)
         - determine whether there is any pre-existing posterior capsular stripping;
         - posterior capsulotomy is performed by detaching it from its acetabular origin;
                - detachment from the femoral origin may disrupt the blood supply to the femoral head, which could lead to AVN;
    - quadrilateral surface:
         - may be palpated through the greater or lesser sciatic notch;
    - dislocation of hip:
         - indicated for interposed intra-articular fragments;
         - consider sliding trochanteric osteotomy for easier dislocation;
         - consider intra operative drilling of the femoral head inorder to demonstrate perfusion; 
    - reference:
         - Surgical dislocation of the hip for the fixation of acetabular fractures

- Complications:
    - sciatic nerve palsy:
           - most common cause of palsy is retraction of sciatic nerve;
           - to avoid palsy, keep patient's knee flexed at least 60 deg & hip extended;
           - if sciatic nerve palsy occurs, it is treated initially with an AFO,
           - there may be improvement in the palsy for up to 3 years

Femoral artery thrombosis after open reduction of an acetabular fracture.

Fractures of the Acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury

Gluteus minimus necrotic muscle debridement diminishes heterotopic ossification after acetabular fracture fixation.

Trochanteric Flip Osteotomy for Cranial Extension and Muscle Protection in Acetabular Fracture Fixation Using a Kocher-Langenbeck Approach.

Long-term results in surgically treated acetabular fractures through the posterior approaches.

Surgically treated acetabular fractures via a single posterior approach with a follow-up of 2-10 years.