Congenital patella dislocation

What it is

A rare congenital limb malformation characterized by permanent and manually irreducible lateral dislocation of the kneecap. It typically presents with flexion contracture of the knee, genu valgus, absent or dysplastic trochlear groove of the femur, external rotation of the tibia, and dysfunction of the extensor mechanism. The defect may be unilateral or bilateral and can occur as an isolated malformation, be associated with other malformations of the lower limb, or be part of a polymalformative syndrome.

Key facts

Prevalence

<1 / 1 000 000

Age of onset

Infancy, Neonatal

Classified as

Morphological anomaly

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Cross-references