Anterior interval arthrofibrosis is a condition where scarring occurs in the knee region known as the anterior interval - the gap that normally exists behind the patellar tendon and in front of the tibia bone.

If such scarring occurs it may contract down and pull the patella into an abnormally low and painful position - known as patella infera (or patella baja) - where it can no longer effectively act as a fulcrum for the quadriceps muscle, and limiting the knee's range of motion.


The circle shows the area of the anterior interval as it contracts up with scar tissue.

normal anterior interval scarring beginning in the anterior interval patella pulled down with arthrofibrosis


Arthrofibrosis and Patella Infera

Patella infera (baja) can be a difficult problem to manage, and surgery may involve the procedure of anterior interval release.