[Two siblings with bilateral congenital knee dislocations: case report].

Congenital dislocation of the knee and congenital permanent dislocation of the patella are rare disorders usually associated with complex syndromes. Two cases of siblings, girl and boy, who had the same clinical phenotype of this disorder are presented. The diagnosis of Desbuquois dysplasia was made and its autosomal recessive heredity was confirmed by genetic analysis. DNA samples were sent for a molecular genetic analysis of the skeletal dysplasia. The girl was surgically treated for a complete (grade 3) anterior dislocation of the tibia on the femur in the first year of life. Redressing casts had not previously been applied to avoid the risk of damaging the epiphysis. The left knee was operated on by the method, as described by Curtis and Fisher, at the age of six months. The Kirschner wire was removed after one month and a plaster cast was applied to maintain the flexion required. At seven post-operative weeks physiotherapy was started with temporary use of a knee brace. The right knee was managed by a similar procedure at four months after the first surgery. Normal walking was achieved at the age of 21 months. Knee motion was symmetrically restricted, with 5 to 90 degrees of flexion. The boy was first seen at our out-patient department after his sister had achieved full walking ability. He was 10 years old at that time and presented with walking problems due to nearly 30 degrees of bilateral knee contractures. Permanent dislocation of both patellae was treated by the surgical technique described by Stanisavljevic. Revision surgery of the right knee due to patellar lateralization was required two years after the primary surgery; it was performed using the Campbell's technique. A corrective osteotomy of the left proximal tibia because of progressive genu valgum was carried out at four years following the first operation. At the last follow-up, the boy was 16 years old and the knee range of motion bilaterally was 0 to 120 degrees with good alignment of both knees. As a result of surgical treatment the two patients gained ability to walk without problems. Key words: bilateral congenital knee dislocation, patella, Desbuquois dysplasia, siblings, skeletal dysplasia, case report.