Congenital dislocation of the knee in a three-year-old-child with Larsen syndrome: Treatment with a hexapod-type external fixator.

Congenital knee dislocation (CDK) is a rare condition, and its treatment is subject to debate. Here, we report on a new treatment for CDK (using a hexapod-type external fixator, HEF) in a three-year-old child with Larsen syndrome and grade III anterior dislocations of both knees. The left knee was treated with serial splints, whereas an HEF was used to treat an irreducible dislocation of the right knee. Two HEF aluminium rings were applied surgically. The procedure involved a distraction of the knee, then tibial posterior translation, and lastly progressive flexion. The clinical and radiological outcomes were good; after four years of follow-up, the right knee had stabilized and had a range of motion of 110°. We conclude that as an innovative, effective option for the management of CDK, the use of an HEF may constitute a relatively advantageous alternative to quadriceps tenotomy.