Closed Reduction of "Irreducible" Posterolateral Knee Dislocation - A Case Report.

INTRODUCTION: Posterolateral rotary knee dislocation is a rare orthopedic injury that is considered to be irreducible by closed reduction because of soft tissue incarceration. Here, we present a case of posterolateral rotary knee dislocation, which was reduced by closed manipulation.

CASE REPORT: The patientwas a 33-year-old man who sustained a twisting injury to his right knee that was diagnosed as posterolateral rotary knee dislocation by plain radiographs and the characteristic physical finding known as a dimple sign. Under general anesthesia, the knee dislocation was reduced by closed manipulation with internal rotation of the lower leg at knee flexion and reproduced by valgus and external rotation stress. There were was complete tear of posterior cruciate ligament, and partial tear of the anterior cruciate ligament which were not reconstructed. The medial collateral ligament that was detached from the femoral footprint was repaired. One year postoperatively, the range of motion was 0-145°. There was no knee symptom and no ligament instability.

CONCLUSION: This is the first report of a successful closed reduction for posterolateral knee dislocation. The mechanism of dislocation was considered valgus and external rotation stress during knee flexion.