(See also Introduction to Congenital Craniofacial and Musculoskeletal Disorders Introduction to Congenital Craniofacial and Musculoskeletal Abnormalities Craniofacial and musculoskeletal abnormalities are common among children. They may involve only a single, specific site (eg, cleft lip, cleft palate, clubfoot) or be part of a syndrome of multiple... read more .)
Anterior knee dislocation with hyperextension is rare at birth but requires emergency treatment. It may occur with Larsen syndrome, which consists of multiple congenital dislocations (eg, elbows, hips, knees), clubfoot Talipes Equinovarus (Clubfoot) and Other Foot Abnormalities Talipes equinovarus, sometimes called clubfoot, is characterized by plantar flexion, inward tilting of the heel (from the midline of the leg), and adduction of the forefoot (medial deviation... read more , and characteristic facies (eg, prominent forehead, depressed nasal bridge, wide-spaced eyes), or with arthrogryposis Arthrogryposis Multiplex Congenita Arthrogryposis multiplex congenita refers to a group of rare congenital disorders characterized by multiple joint contractures present at birth. These disorders result from limitation of joint... read more . The dislocation may be related to muscle imbalance (if myelodysplasia or arthrogryposis is present) or intrauterine positioning. Ipsilateral hip dislocation often coexists.
On examination the leg is extended and cannot be flexed more than a few degrees.
Imaging tests, including x-rays, MRI, or CT of the affected area, are often done.
If the infant is otherwise normal, immediate treatment with daily passive flexion movements and splinting in flexion usually results in a functional knee.