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Lateral Compression Type II Injury / AO Type B2.2

- Discussion: Anterior Lesion:
    - lateral compression injury, contralateral type (Bucket Handle):
    - bucket handle type of injury is usually caused by direct blow to pelvis;
    - anterior fracture may be on the opposite side to the posterior lesion (contralateral type) or all four rami may fracture anteriorly;
    - anterior lesion may involve disruption of only one contra-lateral pubic ramus, all 4 rami or two contra-lateral rami & symphysis pubis;
           - another combination is symphysis disruption with two rami frx;
    - affected hemipelvis rotates anteriorly & superiorly like handle of bucket;
    - affected hemi pelvis rotates internally upto 40 deg;
    - this particlar type may cause a rotatory deformity of the hemipelvis as well as a leg length descrepancy;

- Posterior Lesion:
  - lateral compressive force applied to ilium results in anterior SI complex injury (or sacral frx) one side & displacement of anterior hemipelvis on opposite side;
  - hemipelvis rotates internally, but vertical displacement is prevented by intact sacrospinous and sacrotuberous ligaments;

- Management:
    - reduction requires derotation of hemipelvis rather than traction in vertical plane;
    - this frx remains stable, esp to external rotation & vertical movement, because sacrotuberous and sacrospinous ligaments remain intact;
    - because pelvis is pushed inward, instability is in internal rotation;
           - to overcome this, hemipelvis must be placed in external rotation;
           - since tension bands are intact, reduction will not be overcorrected;
     - closed reduction of a lateral compession type injury is performed by external rotation of the hip with the knee flexed and direct pressure on the hemipelvis using flouroscopy;
     - surgical stabilization is rarely indicated, unless reduction is necessary to correct leg length discrepancy of greater than 2.5 cm;
           - external fixation may be indicated in this case;

- Post Op Care:
    - external fixation frame is left on until union is seen in about three months;
    - wt bearing is commenced on uninvolved posterior side once pt is comfortable;
    - on involved side, weight bearing should be limited for six weeks