Generality
The patellar tendon is the band of connective tissue, which runs from the lower part of the patella to a bony prominence of the tibia, called tibial tuberosity.
Also known as the patellar ligament, the patellar tendon is in continuity with the tendons that join the quadriceps femoris muscle to the upper part and to the edges of the patella.
Equipped with good resistance, the patellar tendon is responsible for keeping the patella in the correct position and supporting the femoral quadriceps in the action of extending the knee.
The patellar tendon can be a victim of inflammation or laceration; the inflammations and lacerations of the patellar tendon concern above all the sportsmen.
The patellar tendon is a source of connective tissue useful for the surgical repair of ligaments, which once damaged cannot spontaneously heal (eg: anterior cruciate ligament of the knee).
Short anatomical reference of the knee
The knee is one of the most important synovial joints in the human body.
Less known as an tibiofemoral joint, the knee joins three bones: the femur, the tibia and the patella .
The femur is the bone of the thigh ; participates in the knee joint with its distal end.
The tibia is the bone which, together with the fibula, constitutes the skeleton of the leg ; opposite to the femur, it participates in the knee joint with its proximal end.
Finally, the kneecap is a triangular-shaped bone that, placed in front of the femur and tibia, creates the classic visible protrusion in the front of the knee; the patella is an insertion site for the quadriceps muscle tendons and provides protection to the articular elements of the knee, located behind her.
Thanks to its strategic position and its structural components, the two knees play a fundamental role in supporting the weight of the body and in allowing the movements of the lower limbs, which are at the base of walking, running, jumping, etc.
What is a synovial joint?
The synovial joints, or diarthrosis, are extremely mobile joints, which include various components, including: the articular surfaces and the cartilage that covers them, the joint capsule, the synovial membrane, the synovial bags and a series of ligaments and tendons.
What is the Patellar Tendon?
The patellar tendon, or patellar ligament, is the band of fibrous connective tissue, which joins the patella to the so-called tibial tuberosity, a characteristic bony prominence of the tibia located on the anterior aspect of the latter.
The patellar tendon is a fundamental structural element of the knee joint, in the same way as the anterior cruciate ligaments, posterior cruciate ligament, medial collateral and lateral collateral ligaments, the articular capsule, synovial membrane, synovial bursa, meniscus and articular cartilage .
Tendons and ligaments: definition and differences
A tendon is a band of fibrous connective tissue, with a certain flexibility and a high content of collagen, which combines a skeletal muscle with a bone.
A ligament is something very similar to a tendon, with the difference that it connects two bones or two distinct parts of the same bone.
Anatomy
The patellar tendon is the resistant band of fibrous connective tissue, which originates from the patella and, proceeding downwards, engages a bony prominence of the anterior aspect of the tibia, whose name is, as anticipated, tibial tuberosity.
The patellar tendon is a flat but broad tendon which, on average, measures 4.5 centimeters in the adult human being.
The patellar tendon represents the inferior continuity of the complex of tendons, which joins the quadriceps femoris muscle to the patella.
Patellar tendon and patella: the details
Belonging to the category of sesamoid bones, the patella is a thick bone, individual to the touch and similar in appearance to an inverted triangle (that is, a triangle with the apex turned downwards and the base upwards), whose area of extension measures about 12 cm2 on average.
Coated with cartilage and articulated at the distal end of the femur through its posterior surface, the patella covers three important functions:
- Contributes to the extension of the knee (and therefore of the leg);
- Increase the efficiency of the quadriceps femoris muscle;
- Protects the internal anatomical structures of the knee.
When the topic of the discussion is the patellar tendon, the most interesting patella area is the apex of the ideal triangle that represents this particular sesamoid bone: it is on the margins, on the front face and on the posterior aspect of the apex of the patella, in fact, which finds the initial end (or proximal end) of the patellar ligament.
Brief review of the proximal-distal terms
" Proximal " means "closer to the center of the body" or "closer to the point of origin"; " distal ", instead, means "farther from the center of the body" or "farther from the point of origin.
Examples:
- The femur is proximal to the tibia, which is distal to the femur.
- In the femur, the extremity bordering the trunk is the proximal end, while the extremity bordering the knee is the distal end.
Patellar tendon and Tibial tuberosity: the details
The tibial tuberosity is the bony prominence of the proximal end of the tibia, detectable by touch, which takes place on the front face of this leg bone, just below the two condyles ; the two condyles of the tibia (or tibial condyles) are the characteristic enlarged areas that form the apex of the proximal end of the bone in question.
To understand where the patellar tendon end its path, it is necessary to identify the tibial tuberosity; the latter is the small palpable hard lump a few centimeters lower than the center of the patella.
Patellar tendon, patella and femoral quadriceps: details
Foreword: readers are reminded that the muscles of the human body are endowed with a tendon, which has the task of fixing them to the bones of the human skeleton.
Based in the anterior thigh compartment, the femoral quadriceps is a complex of 4 muscles:
- The vastus lateralis muscle, which partly originates from the large trochanter and, in part, from the so-called sour line of the femur, and ends at the lateral (or external) edge of the patella;
- The intermediate broad muscle, which originates from the anterior and lateral surfaces of the femoral body and ends at the base of the triangle that ideally represents the patella;
- The vastus medialis muscle, which originates, in part, from the anterior intertrochanteric line and, in part, from the already mentioned rough line of the femur, and concludes its own path on the medial (or internal) edge of the patella;
- Finally, the rectus femoris, which originates from the ilium and ends, like the vast intermediate, at the base of the triangle that ideally represents the patella.
Within this framework, the patellar tendon is placed as the anatomical element that groups the tendons of the 4 terminal heads of the femoral quadriceps and also bonds them, as well as on the patella, also on the tibial tuberosity.
The relationship that the patellar tendon establishes with the tendons of the muscles of the quadriceps femoris explains for what reason to this band of fibrous connective tissue disposed between two bones - therefore, according to the definition, to a ligament - the anatomists grant also the denomination of tendon.
The use of the patellar tendon expression, to define the band of fibrous connective tissue that joins the patella to the tibial tuberosity, is accepted in light of the relationship that this band establishes with the tendons of the terminal heads of the quadriceps femoral muscle.
Borders and Reports
Observing the course starting from the patella, the patellar tendon passes anterior to part of the knee joint and to part of the proximal end of the tibia.
To separate it from the knee there is a fat pad and the synovial membrane of the aforementioned articulation; to separate it from the tibia, instead, there is a synovial bursa, called a deep infrapatellar bursa .
Function
The patellar tendon covers two important functions:
- Helps keep the kneecap in the correct position e
- Supports the femoral quadriceps in the action of extending the knee, an action that is fundamental in activities such as walking, running, jumping, kicking a ball, etc.
Without the patellar tendon, the patella would slide upwards and the lever that helps to extend the knee (and leg) disappears.
The patellar tendon is an essential structure for the correct functioning of the knee.
diseases
The patellar tendon can be subject to various medical conditions, including: inflammation, rupture and a syndrome known as Osgood-Schlatter disease .
Inflammation of the patellar tendon
An example of tendonitis, the inflammation of the patellar tendon (or patellar tendinitis or jumper's knee ) is a suffering from functional overload, which recognizes the excessive cause in the excessive repetition of the jumping gesture.
Inflammation of the patellar tendon is a condition that sportsmen suffer in particular, particularly those who practice sports such as: volleyball, basketball, football, athletics, tennis, artistic gymnastics and skiing.
Patellar tendinitis causes fairly typical symptoms, which includes:
- Pain in the patellar tendon. This pain improves with rest, while it worsens with physical activity (especially if it includes jumps or running);
- Sense under the knee;
- Thickening of the patellar tendon;
- Sense of stiffness at knee level.
To reach the diagnosis of a condition such as inflammation of the patellar tendon, they are generally sufficient: the patient's account of the symptoms, the physical examination and the anamnesis; only in rare cases, radiological examinations are also required.
The first-line treatment of patellar tendinitis is conservative and is based on:
- The rest of the lower limb in pain, until the complete disappearance of the pain and the other symptoms (in this situation, rest is meant not to practice any physical activity that involves jumping and running);
- The application of ice on the painful area from 3 to 5 times a day and for a duration of 15-20 minutes at a time;
- The intake of Non-Steroidal Anti-Inflammatory Drugs ( NSAIDs ), in order to promote the disappearance of pain;
- Physiotherapy sessions, aimed at improving the elasticity of the inflamed tendon and related muscles (eg, quadriceps femoris).
If the conservative management of inflammation of the patellar tendon should fail and the symptoms associated with the condition remain without improvement for several months, the patient can do nothing but undergo a decisive surgical operation, with all that follows (period of convalescence, physiotherapy and gradual recovery of physical activity, even the lightest).
Neglecting a patellar tendinitis, continuing in the physical activity that caused it, is a very dangerous behavior, because it can lead to the rupture of the patellar tendon.
Patellar tendon rupture
The rupture of the patellar tendon is a medium to high severity injury, which occurs when a partial or complete laceration of the tendon in question occurs.
The rupture of the patellar tendon has, in general, a traumatic origin ; however, as previously mentioned, it can also derive from a neglected patellar tendinitis.
Typical of those who practice sports in which there is a strong and repeated stress on the knee and the quadriceps femoris, the rupture of the patellar tendon is associated with an unequivocal symptomatology, which includes:
- Sharp and sudden pain under the rupture, which appears immediately after the tendon is torn;
- Snap to the occurrence of the laceration event;
- Palpable indentation to the touch during laceration;
- Swelling and bruising at the patellar tendon;
- Sense of sagging at knee level;
- Difficulty walking ;
- Upward sliding of the patella, due to the lack of anchoring to the tibial tuberosity.
Generally, the diagnosis of a patellar tendon rupture is based on: symptom narrative, physical examination, medical history and an imaging test such as, for example, knee MRI.
The therapeutic management of the patellar tendon rupture usually requires surgery, as there is no possibility of a spontaneous healing of the laceration.
The surgical treatment of the patellar tendon rupture episodes consists of an operation aimed at restoring the physiological continuity of the injured tendon structure.
After the surgical operation, the perfect recovery from a rupture of the patellar tendon requires the patient several months of physiotherapy and a gradual approach to any physical activity .
Did you know that ...
If the rupture of the patellar tendon is partial and very slight, it is possible to adopt a conservative treatment based on rest, use of a brace for the knee and appropriate physiotherapy, which however is not always successful.
In case of failure of the aforementioned conservative treatment, there is nothing left but to resort to surgery.
Osgood-Schlatter disease
Also known as Osgood-Schlatter syndrome or anterior tibial apofisite, Osgood-Schlatter disease is the set of symptoms and signs, resulting from the inflammation of the patellar tendon at the level of its insertion on the tibial tuberosity.
What causes Osgood-Schlatter disease is the tension that the patellar tendon can exert towards the extremity of the tibia, in the years of the musculoskeletal growth of the human being .
Typical of adolescents between the ages of 10 and 14, Osgood-Schlatter disease causes pain and swelling where the patellar tendon attaches to the tibia.
Osgood-Schlatter disease is a usually temporary condition, which heals spontaneously with the conclusion of musculoskeletal development or with a more balanced evolution.
Clinical Use
The patellar tendon has a role of some importance also in the clinical-therapeutic field; the patellar tendon, in fact, can serve as a source of tissues for surgical repair of ligaments .
An example of a ligament whose surgical repair may involve taking a part of the patellar tendon is the anterior cruciate ligament of the knee.
