Synonyms
Runner’s knee
Introduction
Patellar tendonitis is a painful disease of the connective tissue ligament that connects the patella and the tibia. In the vast majority of cases, patellar tendon inflammation affects only one side, but bilateral patellar tendon inflammation occurs in about 10-20% of cases. The most common cause is chronic overloading, often in combination with malalignment, incorrect weight bearing or increased friction.
The disease has a tendency to be noticed late and to be taken seriously and treated too late and therefore often becomes chronic. The most frequent complications of patellar tendon inflammation are chronification and changes in the tendon structure. The worst complication in the case of an infectious cause is the spread of the pathogens to the periosteum (periosteum) of the tibia (tibia) or even a spread via the bloodstream (sepsis). The treatment is usually conservative. The prognosis is good with appropriate patient discipline.
Anatomy
The largest knee extensor muscle (Musculus quadriceps femoris) has its origins in the pelvic bones and thigh bones (femur). Its four parts together pull the kneecap (patella) upwards. This is connected to the shin bone (tibia) via the patella tendon.
If the muscle quadriceps femoris is shortened, the leg is stretched in the knee joint by pulling on this tendon. In accordance with the size of the muscle and its task of maintaining the entire body weight in standing, walking and jumping, the patella tendon is quite broad and very durable in a healthy condition. In an untrained person, it can bear about seven times its body weight without tearing (rupturing). Inflammation of the tendon is particularly likely to occur in cases of chronic overloading or regular rubbing of the tendon against bony structures of the knee. Such rubbing is particularly likely in the case of malposition or incorrect posture in the knee joint or muscular imbalances (especially between the different parts of the quadriceps femoris muscle), especially if this causes the kneecap to leave its normal path due to inadequate or incorrect guidance.
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