Patellar Clunk Syndrome

Introduction:

This is a syndrome which occurs when a fibrous nodule forms on the joint capsule, just above the patella. This is a complication of Total Knee Replacement and once this develops the Knee starts making a loud clunk. At about 40 degrees of flexion this lump gets trapped between the anterior flange of the femoral component and hence the clunk.

Causes:

According to the theories there are two causes:

• Design of the implant
• More than average flexion of the Knee

Clinical Findings:

Discomfort and pain in the knee, loud clunk on flexion, blocking of further movement, synovitis, effusion.

Prevention:

With the use of the newer designs of the total knee prosthesis very few cases of patella clunk have been seen. This is because the newer designs offer a much longer and deeper groove for the patella to fall back into the notch of the femur.

Treatment:

Removal of the lump by Arthroscopy of the Knee Joint.