Among the causes of acute knee pain directly caused by accidents are Below is a brief informative description of the respective clinical picture. – Articular effusion
- Free joint body
- Acute Baker cyst
- Hematoma in the knee
- Cruciate ligament rupture
- Torn meniscus
- Sideband rupture (inner/outer band)
- Broken bone
- Patellar luxation
- Runner’s knee
This is often caused by effusions caused by inflammation of the joint or after irritation by free joint bodies, Baker cysts or the Plica syndrome. Gout can also cause fluid accumulation after the crystals have been deposited. On the other hand, there are bloody joint effusions that occur after various injuries to the knee.
Therapeutically, the basic disease that led to the joint effusion must be treated first. Large effusions can also be punctured with a needle. On the one hand, this allows the diagnosis to be confirmed by examining the fluid, on the other hand, it also relieves the strain on the effusion and reduces the symptoms.
Smaller joint effusions in the knee can resorb themselves, so that puncture is not always necessary. The name “Hoffitis” reveals that it is an inflammatory change in the Hoffa fatty body in the knee. The fatty body lies below the kneecap and thus between the 3 bones connected in the knee joint.
After minor accidents of the knee, or even without a recognisable cause, the fat body can grow strongly and swell. The fat body changes, becomes inflammatory and coarse and can cause unpleasant pain and restricted movement in the knee joint. A free joint body is also called a joint mouse.
This refers to a structure that lies inside the knee joint, is freely movable and has no function. This can be parts of the bone, cartilage, the joint capsule but also other tissue accumulations. A free piece of tissue in the joint need not cause any symptoms, but depending on its position and size, it can cause extreme discomfort.
Some affected persons can already feel severe pain in the knee during sports and everyday activities, which is caused by irritation of the joint structures. If the symptoms are too severe, the joint body can be removed by means of a joint endoscopy. A Baker’s cyst can also be an underlying clinical picture that is responsible for acute knee pain.
A cyst is a fluid-filled bladder that can form in various parts of the body. Cysts can often grow over the years and cause increasing discomfort. The Baker cyst lies behind the knee joint in the hollow of the knee.
It is often preceded by minor knee injuries or inflammation, which cause the cyst to form for the first time. Especially when the knee is bent, it can cause an unpleasant feeling of pressure in the hollow of the knee, pain and a tingling sensation in the lower leg. A sustainable therapy for Baker’s cyst consists in the repair of the damage to the knee.
A hematoma in the knee is a special form of joint effusion. Blood accumulations always occur as a result of the injury to smaller blood vessels inside the knee joint capsule. In most cases, this is caused by an injury to the inner joint structures.
The most common injuries of this type are torn meniscus, torn collateral ligaments, torn cruciate ligaments, broken bones in the knee and injuries to the kneecap. During treatment, the underlying injury must first be treated. Larger effusions, on the other hand, often have to be punctured additionally.
An arthroscopy can also be performed if the knee is bruised. However, subsequent operations and operations on the knee can in turn cause haematomas. The haematoma itself can already lead to severe pain and restricted movement of the joint.
The human knee has 2 cruciate ligaments that are stretched between the joint surfaces of the knee and are under strong tension. They play a decisive role in the stability of the knee and inhibit the extension and rotation of the knee, as well as the mobility of the thigh in relation to the lower leg. Cruciate ligament ruptures occur mainly in sports accidents without external influence.
Frequently, the rapid rotation of the lower leg is a typical force that leads to a torn cruciate ligament. Acute knee pain after a torn cruciate ligament is mainly caused by the bruising and tension of the joint capsule. The main symptom of a torn cruciate ligament itself is often only instability in the knee.
The menisci are cartilage discs that provide stability in the joint, cushion movement and compensate for the uneven joint surfaces. Similar to the cruciate ligaments, the menisci of a knee can also tear in sports accidents or in rapid, abrupt movements. In order to be able to fully diagnose the tear, an arthroscopy or an MRI must often be performed.
Similar to the rupture of the cruciate ligament, the pain is mainly caused by the hematoma in the knee and the resulting increase in tension in the joint. Mobility is also significantly restricted as a result. During therapy, the benefits of an operation must be carefully weighed up.
Meniscus sutures are possible but not always useful or necessary. The so-called “collateral ligaments” are located on the inside and outside of each knee joint and ensure the lateral stability of the knee. Tears occur due to strong lateral force on the inside or outside.
Even in the following examination, the knee can then be opened outwards in the event of a torn outer ligament. The subsequent pain is moderate and occurs mainly under stress. As a rule, a torn collateral ligament only needs to be spared for a few weeks.
Complete stability and recovery can be expected after about half a year at the earliest. Broken bones in the knee are comparatively rare. A bone fracture often occurs only as a result of direct, external force, and more rarely as a result of torn ligaments, which cause bone splinters.
The most common causes of accidents are direct falls onto the knee or car accidents. The femur, patella and tibial head can be involved in a fracture of the knee. Immediately after the accident, there is acute knee pain and swelling of the knee due to bruising.
The different locations of the fractures are associated with different symptoms and treatment options. Non-displaced fractures can be treated with a plaster cast and relief if necessary. In most cases, however, surgical correction and the insertion of plates and screws are necessary to stabilize the bone fragments.
Patellar dislocations (dislocation, dislocation) can occur frequently and recur repeatedly. Often a one-time accident with twisting of the leg is behind the dislocation. Afterwards, the ligament structures can be changed in such a way that even slight external influences can cause dislocation.
A patellar dislocation can be acutely very painful and often leads to a temporary joint effusion, which in turn causes swelling and pain. The patella can be repositioned after the dislocation. In the long term, however, the quadriceps muscles should be strengthened to prevent further dislocation.
The runner’s knee describes a painful tendon irritation of the outer knee, which occurs mainly in runners, cyclists and athletes with very frequent bending and stretching of the knee. Behind this is the tendon of the so-called “iliotibial ligament”, which runs closely past the bony protrusion of the thigh bone just above the outer knee. Due to the frequent bending, painful irritations can occur at this bony protrusion, which can only be prevented by permanent protection. In the long term, the movement sequences must be adapted by certain loosening exercises, running shoes and other measures in order to prevent the Iliotibial Ligament Syndrome.