[2] Injury to the patellar tendon generally requires a significant force such as falling directly on the knee or jumping from a height.

[1] Risk factors include patellar tendinitis, kidney failure, diabetes, and steroid or fluoroquinolone use.

When rupture occurs, the patella loses support from the tibia and moves toward the hip when the quadriceps muscle contracts, hindering the leg's ability to extend.

[citation needed] Patellar tendon rupture can usually be diagnosed by physical examination.

With a tourniquet applied, the tendon is exposed through a midline longitudinal incision extending from the upper patellar pole to the tibial tuberosity.

The usual risks of surgery are involved, including: infection, stiffness, death, suture reaction, failure of satisfactory healing, risks of anesthesia, phlebitis, pulmonary embolus, and persistent pain or weakness after the injury and repair.

[6] In 2010, a clinical study proved that mechanical loading of the tendon callus during the remodelling phase leads to healing by regeneration.