Congenital dislocation knee, Paediatric-
Sign, Symptoms & Treatment

What is Congenital dislocation knee:

Congenital dislocation of the knee is a hyperextension deformity of the knee with varying degrees of anterior displacement of the tibia (leg bone) in relation to the femur (thigh bone). It is rare and found in 1 to 2 of 1 lac live birth. More common in female

Associated problem :

CDK can be presented with many other problems like equinovalgus/ congenital vertical talus, club foot, congenital hip dislocation, Forefoot adduction deformity

Grading of congenital knee dislocation:

Grading is based on the possible range of movement at the knee and the reducibility of the joint.
Grade 1: hyperextension of the knee with a possible range of movement at the knee is possible till the 90 degree
Grade 2: knee joint is dislocated, and 30 degrees to 90-degree knee flexion movement is possible with manipulation
Grade 3: irreducible dislocation

What are the causes of Congenital dislocation knee:

Many causes have been given, but it is because of less intrauterine space, fetal malposition, and quadricep fibrosis. It is also associated with genetic diseases like Larsen syndrome, arthrogryposis multiplex congenital &meningomyelocoel

Diagnosis: diagnosis of CDK is clinical examination based:

On examination, skin fold over the knee, posterior aspect of femur condyle is seen behind the tibial condyle and decrease in a knee flexion movement. Etc. X-ray of knee AP& the lateral view is required

What is the treatment available:

Does treatment start after the delivery of the child?
We need to examine the child in detail. If the joint is manually reducible as

In grade 1- then weekly manipulation and plaster are given for few weeks, followed by Pavlik harness.

In grade 2- if with 1 or 2 manipulation joint can be reduced, then weak manipulation and plaster will be given otherwise percutaneous Tenotomy under anesthesia is advised.

In grade 3- we need to see other associated problems. In this grade, most children need surgery. In surgery, lengthening of quadriceps (quadricepplasty) or femoral shortening is necessary.

Prognosis:

Congenital dislocation is present alone without any other problem; the child will have nearly normal knee movement without much laxity or weakness. However, if the child has syndrome-like AMC, Larsen syndrome, the child will need physical therapy for a long duration. Mild; laxity, deformity, and stiffness may present forever. But the child will develop walking capability without support by good rehabilitation.

Reference Links :

• https://posna.org/Physician-Education/Study-Guide/Congenital-Knee-Dislocation
• https://en.wikipedia.org/wiki/Knee_dislocation#:~:text=A%20knee%20dislocation%20is%20an,the%20knee%2C%20or%20compartment%20syndrome.
• https://www.karger.com/Article/FullText/516134
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058203/

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