Infrapatellar contracture syndrome is a condition of excessive scarring behind the patellar tendon, in the infrapatellar area.
Page updated September 2023 by Dr Sheila Strover (Clinical Editor)
Normal tissues below the patella and the patella in a normal position.
Infrapatellar contracture syndrome with the tissues scarred below the patella and the patella pulled down.
What causes the scarring?
This condition is likely to have followed a traumatic or surgical incident to the knee, where the joint was full of blood or joint fluid, or both. With healing, the body gradually absorbs the fluids, with the residual fluid becoming thicker and stickier and forming 'adhesions', which can stretch from wall to wall.
When these adhesions are still soft, the strands can be broken with physiotherapy procedures such as patellar mobilisations and massage around the patellar tendon. But if this is not done, the body will allow repair cells to migrate into the space and to turn the adhesions into proper scar tissue, which then contracts and pulls the walls of the space tightly together. At this stage it is too late for physiotherapy, and surgery becomes indicated to remove the scar tissue, probably using an arthroscopic radiofrequency wand, which disrupts the structure of the scar tissue..
Patella infera or baja
Gradually, the contracting scar tissue may pull the patella itself into an abnormally low position, which is called 'patella infera' or 'patella baja'. This may lead to chronic pain from increased pressure on the upper surface of the patella.
The fat pad can also become involved in the scarring process.
- possible patella baja
Patients with early patella baja compare notes.
"[Infrapatellar contracture syndrome] involves a complex interaction between quadriceps dysfunction, immobilization, and inflammation leading to infrapatellar scarring and adhesions....associated with fractures about the knee and ....surgical procedures such as anterior cruciate ligament (ACL) reconstruction,....high tibial osteotomies (HTOs), tibial tubercle osteotomies (TTOs), and total knee arthroplasties (TKAs)....Allografts and autografts can be utilized to augment tendon lengthening or reconstructive procedures."
Citation: Barth KA, Strickland SM. Surgical Treatment of Iatrogenic Patella Baja. Curr Rev Musculoskelet Med. 2022 Dec;15(6):673-679. doi: 10.1007/s12178-022-09806-y. Epub 2022 Nov 29. PMID: 36445621; PMCID: PMC9789255.