Assistant
Definition
By Gregory R. Waryasz, MD
The patellar ligament/tendon of the musculoskeletal system is characterized by transferring high tensile loads from the inferior pole of the patella to the tibial tubercle. In the literature it is referred to as the patellar ligament or the patellar tendon.
It is part of the knee joint. It consists of fibrous densely packed collagen fibers.
Its unique structural feature is that it is strong and flat. It measures approximately 10cm in length. The patellar ligament/tendon attaches the inferior pole of the patella to the tibial tubercle. It receives fibers from both the medial and the lateral retinacula. The large infrapatellar fat pad lies posterior to the patellar ligament/tendon.
The patellar ligament/tendon as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.
The function of the patellar ligament/tendon is to transfer forces from the inferior pole of the patella to the tibial tubercle. The extensor mechanism provides a mechanical advantage for moving the knee joint.
Common diseases include “jumper’s knee”/patellar tendinopathy, rupture/tear, patellar dislocation/subluxation, Osgood-Schlatter disease, and Sinding-Larsen-Johansen disease.
Sinding-Larsen-Johanssen disease is a condition of pain at the inferior pole of the patella in preteen boys due to traction on the patella by the patellar ligament.
Osgood Schlatter is a condition of juvenile traction osteochondritis where there is partial avulsion of the tibial tuberosity. It tends to be more common in early adolescent boys.
Patella dislocation/subluxation typically occurs laterally due to the stronger lateral restraints. Often the medial patellofemoral ligament is injured.
“Jumper’s knee” refers to a tendinopathy typically in athletes the run or jump frequently.
The patellar ligament/tendon can have tissue harvested for repair of other ligaments including the anterior cruciate ligament.
Commonly used diagnostic procedures include clinical history, physical exam, x-ray, CT-scan, and MRI.
It is usually treated with physical therapy and NSAIDs. Patellar ligament/tendon tears require surgery. Sinding-Larsen-Johanssen and Osgood Schlatter disease are treated non-operatively with quadriceps strengthening exercises and other physical therapy modalities.
References
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.