Definition
The quadriceps tendon is the muscle attachment tendon of the powerful Musculus Quadriceps, which is located on the front of the thigh and is responsible for the powerful extension of the knee. While the different muscle parts originate from different structures, the quadriceps tendon attaches to the tibial tuberosity, which is prominently located on the shin. The patella is embedded in the quadriceps tendon.
The quadriceps tendon continues from the patella as the ligamentum patellae. Inflammation of the quadriceps tendon usually occurs at the transition to the bone, i.e. where the tendon starts at the upper pole of the patella, originates at the lower pole and ends at the tibia. It is a sign of chronic overloading.
Causes
Inflammation of the quadriceps tendon usually results from chronic overloading of the tendon and all structures connected to it. Chronic overloading occurs mainly during regular jumping, playing sports or running, but also during professional activities that are mainly performed while kneeling, such as tiling. Due to the heaped and strong contraction of the quadriceps muscle, an enormous tension is in principle constantly exerted on the quadriceps tendon and the connected bone attachment.
In addition, an axial misalignment, such as bow legs, can negatively influence the traction of the quadriceps tendon, which places greater strain on it. The effect of force is greatest at these tendon-bone boundaries, which is why inflammation tends to occur there. In the course of chronic inflammation, metabolic processes can lead to calcification of the tendon, which in turn leads to pain and degeneration, i.e. wear and tear, of the tendon apparatus.
If the quadriceps tendon is already too badly affected and damaged by the inflammation process, it can no longer withstand the high forces during movement and tears can occur. In the worst case, a partial – or even complete rupture of the quadriceps tendon may follow as a result of the inflammation. The diagnosis of the inflammation of the quadriceps tendon is first made according to the clinical picture.
This means that the patient visits a doctor because he or she has noticed pain or a restriction in the movement of the knee, and the doctor then characterizes the symptoms precisely on the basis of a physical examination and a medical history. The focus is particularly on the point where the quadriceps tendon attaches to the kneecap and the tibia. There, the pressure pain can typically be localized exactly to one point, in some cases even a swelling, hardening due to calcification or a dent after a rupture of the tendon.
In addition, various tests can be used to determine the strength and function of the quadriceps tendon during knee extension in order to define the extent of the inflammation. It is important to differentiate between the two types of knee joint, as the knee joint itself is not impaired in its function. A detailed anamnesis can provide additional information on the development of the inflammation, its course and symptoms.
Furthermore, imaging measures can be performed, such as an ultrasound of the quadriceps. In this way, the tissue of the tendon can be well assessed with the question of inflammation or rupture. Typical signs of inflammation are calcification, water retention, loss of smooth boundaries of the tendon fibres or rupture. Alternatively, a lateral x-ray of the knee can be taken, again looking for calcification in the quadriceps tendon. To clarify a rupture of the tendon, an MRI image of the knee is taken, since this allows better differentiation of the soft tissue of the quadriceps tendon and thus also determines the thickness, which should not be less than approximately 7 mm.
