The 'anterior interval' is the region of the knee between the fat pad and the front of the tibia bone (anterior tibial plateau) and the patellar tendon.
The anterior interval is one of those areas of the knee that can become locked up with adhesions, resulting in a stiff knee.
This is a condition where scarring occurs in the space behind the patellar tendon - the 'anterior interval' - eventually contracting down and pulling the patella into an abnormally low and painful position, and limiting the knee's range of motion.
Dr Peter Millett discusses why knee surgeons need to be aware that arthrofibrotic scarring can occur in this area because of the position of their arthroscopic portals (cuts).