Associated symptoms
A bump on the knee can have various accompanying symptoms that can give an indication of the cause of the bump. Inflammation is usually accompanied by redness and overheating. In addition, there is usually pain, which often has a throbbing character.
It does not make any difference with regard to the symptoms which cause of the inflammation is underlying. If fever and a worsening of the general condition occur in addition, a doctor should be contacted promptly. A bump in the hollow of the knee due to a Baker cyst can be an accompanying symptom that can lead to a restriction of movement. The knee joint can often no longer be bent normally, so that it is no longer possible to kneel or squat, for example. In addition, some people experience tingling or numbness in the lower leg.
Bump on the knee without pain
If a bump on the knee occurs that does not cause pain, the most common causes of a bump, such as inflammation or the result of an injury, are rather unlikely. Instead, other causes are more likely to occur in this constellation. The most common cause of a bump on the knee without pain is a Baker cyst.
This bulging of the joint capsule occurs in the hollow of the knee and only needs to be treated if it causes pain. Patients who suffer from a blood coagulation disorder or who are taking blood-thinning medication can also suffer from bleeding, which can manifest itself, among other things, as a bluish bump on the knee, which need not cause pain. An extremely rare cause of a bump on the knee is also a benign or malignant soft tissue or bone tumour. Here, too, there is often no pain. Therefore, a bump on the knee should be examined by a doctor especially if it is constantly increasing in size, even if it does not cause pain or other complaints.
Diagnosis
The most important measure to make a diagnosis of a bump on the knee is a physical examination by a doctor. On the basis of the localisation, size and condition as well as other factors such as reddening or overheating, it is already possible in many cases to determine what the cause of the bump is and what measures are indicated for treatment. The doctor also collects important information for the diagnosis by asking specific questions about the possible course of the accident, concomitant diseases and long-term medication of the patient.
Only in certain cases is further examination necessary to establish a diagnosis. For example, an ultrasound image of the bump on the knee can be obtained. In addition, if an inflammatory event is suspected, the doctor may take blood samples in order to determine the inflammation values.
In the case of a serious bacterial inflammation, the knee joint sometimes needs to be relieved by a puncture with a hollow needle. A sample of the joint fluid can then also be sent to a laboratory for examination. Only in rare cases, for example if there is suspicion of ligament structure injury, can further diagnostics such as an MRI (magnetic resonance imaging) be useful as a further imaging procedure.
