Patellar straps, occasionally just called knee straps, are applied just under the knee cap. The idea is to press on the patellar tendon and tighten up the knee mechanism, providing support to the knee cap so that it is not constantly thumping against the femur. The effort not only helps to ease the discomfort of patella-femoral pain syndrome, but it keeps the cartilage that would normally prevent contact from degenerating any further.