Irreducible posterolateral knee dislocation resulting from a low-energy trauma.

A small amount of knee dislocations is included in the irreducible knee dislocations group. In such instance, medial femoral condyle is buttonholed through the gap formed by medial retinacular and capsular structures and this prevents reduction. In this study, we present two cases in which there were irreducible posterolateral knee dislocations resulting from a low-energy trauma. In both cases, dimple sign produced by the invagination of the medial retinacular structures and capsule and ecchymosis medially were noted. Soft tissue invaginated between the trochlea and intercondylar notch was extracted by open reduction.