Knee injuries and knee joint traumas occur when mechanical forces overwhelm the physiological capacity of the knee. The injuries can affect the ligamentous structures, menisci, and articular cartilage. They occur as a result of external force, but can also be caused by peculiarities of the body structure.
What are knee injuries?
Movement causes mechanical stress on the knee joint. The range of motion is determined by the physique. External forces or influences from within the body can force the joint to exceed its biomechanical limits during motion. If knee joint traumas occur as a result of external forces, direct or indirect forces play a role. A direct force acts when there is an impact or blow against the joint, and an indirect force acts when there is bending, compression or shearing. Misloading or overloading can also be due to the nature of the body structure and physiological processes. If force acts against the plane of motion of the joint, cruciate ligaments, collateral ligaments, or menisci can tear (rupture). A combined knee joint injury occurs when several of the anatomic components of the knee are affected by a rupture (“unhappy triad”).
Causes
One cause of knee injuries is the action of external forces against the plane of motion of the joint. In addition, degenerative processes and anatomic deformities can cause trauma to the knee. External force from a blow or impact causes bruising. Twisting or shearing of the knee joint causes sprains. The traumas can occur due to accidents in everyday life or as a result of sports injuries. Jumping, twisting, and sudden stops in motion, such as skiing or playing soccer, can cause meniscus damage or tears of the anterior cruciate ligament. Dislocation of the patella occasionally occurs in patients under 20 years of age. As a result of a violent impact against the lower leg or knee, ruptures of the posterior cruciate ligament are possible. If forces act perpendicular to the natural direction of motion, ruptures of the collateral ligaments are possible. Degenerative wear of the menisci occurs as a result of the natural aging process, obesity, one-sided loading during predominantly kneeling activities, or genetic predisposition. Damage to the ligaments can be caused by biomechanical dysfunction in the case of axial malalignment (knock knees, bow legs). Damage to the joint cartilage (arthrosis) is the result of meniscus and ligament trauma or is itself due to degenerative wear and tear.
Symptoms, complaints, and signs
Symptoms of knee injuries allow conclusions to be drawn about specific types of injuries in numerous cases. Clear signs of a fracture of the kneecap (patella) include axial misalignment, unnaturally large range of motion, and identifiable bone fragments. Signs of a patellar luxation (dislocation of the patella) are pain in the front of the knee and excessive outward movement of the patella. With a meniscus tear, there is severe pain in the knee as well as swelling. A noise may be heard. The affected knee joint can only be moved to a limited extent and can no longer be fully loaded. Primarily, stretching the knee causes problems. Typical is the feeling of instability in the knee joint when walking or running. Ligaments in the knee can be strained as well as completely or partially torn. Symptoms include pain in the area of the affected ligament and significant swelling. The knee’s ability to move and bear weight is restricted. If there is pain in the knee joint that is not under load, cartilage damage may be present. Typical complaints indicate a cruciate ligament tear. It causes significant pain and is audible as a cracking sound. There is severe swelling as well as a feeling that the lower leg is shifting against the thigh. The knee is unstable and prevents a safe gait. The joint may suddenly pop out of place. Swelling, hyperthermia and redness of the skin are obvious signs of a bruised knee. Likewise, in many cases, a bruise is visible.
Diagnosis and progression
Tears of the meniscus cause pain at the joint space that continues into the back of the knee. They are particularly severe with pressure and strain. Rotational movements of the knee are also painful. If the meniscus is entrapped, the joint may become locked. A joint effusion may be palpable.Arthroscopy is usually performed to confirm the diagnosis. Ruptures of the cruciate ligaments cause acute pain and lead to an effusion into the joint. It is bloody in the initial period after the injury and causes the knee to swell considerably. Various tests are used to check whether the ligaments still provide sufficient support when the lower leg is moved against the thigh. In the case of both damage to the ligaments and meniscus ruptures, X-rays or a magnetic resonance imaging scan are taken for diagnostic clarification so that an injury to the bones can be ruled out.
Complications
Knee injuries can be very varied, so the associated complications can also vary widely. Most knee injuries result from overstretching of the ligaments. If individual ligaments within the knee are overstretched too much, they can tear. If such a condition is left untreated, various complications can be expected. The torn ligaments cannot grow back together on their own without surgical intervention, so that the pain remains permanent. Under certain circumstances, the knee joint can become inflamed, resulting in the formation of an abscess. An abscess is an accumulation of pus fluid, which in particularly bad cases can even cause blood poisoning. In such a case, there is an acute danger to life. Treatment by a specialist is inevitable in such a case, because otherwise the above-mentioned complications will worsen considerably. Among the possible knee injuries is, of course, a fracture. An operation may even be necessary, otherwise a fracture cannot heal properly or grow together. Since knee injuries can cause a wide variety of complications, an early visit to a doctor is recommended to prevent the symptoms from worsening. Only professional treatment can prevent the above complications.
When should you see a doctor?
The most important criterion for whether to go to the doctor is the extent of the injury. If there is an obvious fracture of bone substance or instability that indicates a ligament or tendon injury, the doctor is the right person to contact. The same applies to severe pain that does not disappear even with cooling and immobilization. Here, too, a visit to the doctor is necessary to rule out a meniscus injury, for example. Heavy bleeding that is difficult to stop is also a cause. This is especially true in the case of a heavily contaminated wound and the possible need for a shot against tetanus. In many cases, a knee injury can be cured by self-treatment without a visit to the doctor. Especially for children with abrasions, cleaning, covering and, if necessary, sparing is often quite sufficient. The situation is different if a wound has become infected. This is often easy to recognize by the classic signs of inflammation, even for the layman. Redness, hyperthermia, swelling and a throbbing pain are possible signs of infection, as is the secretion of a yellowish wound secretion. Going to the doctor is also important if there are foreign bodies in the wound that cannot be removed by the patient himself. Contact with corrosive substances or fire is also a reason to have the skin of the knee looked at closely.
Treatment and therapy
Treatment of knee joint trauma depends on the anatomic structures involved, biological age, general health, and the patient’s activity level. Tears of the menisci are treated during arthroscopy. If patients are younger than 40, suturing is promising. Otherwise, the damaged tissue is removed as gently as possible. The more extensive the meniscus resection, the higher the risk of wear to the articular cartilage. Cruciate ligament tears are treated both conservatively and surgically. Often, conservative treatment is sufficient. The knee is supported by an orthosis and is sufficiently stable again after 6 weeks. Supportive puncture of the bone in the area of the cruciate ligament is possible, so that escaping stem cells can contribute to the healing of the injury. In younger athletic patients, the cruciate ligament tear is treated surgically. The type of injury determines whether the ligament is sutured or replaced with a cruciate ligamentoplasty. For cruciate ligament reconstruction, the patient’s own replacement tissue or synthetic prostheses are used. A tear of the cruciate ligament on the bone is fixed with a screw or wire suture.After surgery, the leg is stabilized by an orthosis. The ability to bear weight occurs gradually and is fully achieved after 10-12 months. The treatment of a cruciate ligament tear is always accompanied by physiotherapy. The emphasis is on strengthening the muscles and coordination training.
Outlook and prognosis
The prospect of recovery in knee injuries must be assessed according to the individual circumstances. In most cases, with prompt and comprehensive medical care, freedom from symptoms occurs after a few weeks or months. The sooner treatment takes place and sufficient rest is given to the knee, the better the course of the disease. Normally, conservative therapy is sufficient. In the case of severe injuries, surgical intervention is necessary. This is associated with risks and side effects. If no further complications occur, a favorable prognosis can be expected. Without treatment, the affected person often suffers from severe and increasing pain. In some patients there is a possibility of recovery without further medical measures. However, this is the exception. On the contrary, there is a risk of permanent disturbance of joint activity, irreparable damage to the bones and cartilage, and a decrease in physical capacity. Knee injuries can lead to lifelong instability of the knee. Despite all efforts, chronic sequelae may occur. These trigger an unfavorable prognosis, as an increase in impairments can be expected over the lifespan. In addition, there is a risk of no longer being able to perform sporting or professional activities as usual. This leads to emotional distress and increases the likelihood of mental illness.
Prevention
To prevent knee injuries, gentle movement patterns are learned. The knee is protected when the angle and axis of flexion are consciously controlled during loading. Coordination and muscle training are essential for knee function and stability. Holistic training of the joint is possible when cycling. Weight and dietary habits are also important for knee health. After injuries, elastic bandages have a stabilizing effect.
Aftercare
Knee injuries need consistent aftercare for optimal recovery. This is ensured by several groups of people. First, it is the attending physician such as the sports medicine or orthopedic surgeon who coordinates the aftercare and may order imaging procedures by a radiologist again for this purpose. Secondly, it is the physiotherapist who reactivates the functionality of the joint and surrounding structures through his treatment. Thirdly, the cooperation of the patient is also required, who, for example, carries out physiotherapeutic exercises regularly at home or in the gym and can thus ensure the success of the treatment. Rest is very important for optimal regeneration. The duration is decided by the physiotherapist and the doctor, but it is the patient who must follow these instructions. Athletes in particular often have a tendency to want to return to training and competition too soon. However, to avoid a relapse or delayed recovery, it is better to do the prescribed physiotherapeutic exercises in this case. These serve to strengthen the muscles surrounding the joint and also restore mobility in the knee joint as best as possible. If the knee joint injury is accompanied by a wound suture, sparing is especially important. Stability is an important factor when it comes to the knee joint. Therefore, appropriate splints should also be worn consistently as part of aftercare.
What you can do yourself
The relief of knee injuries can be accompanied by various options in support of medical treatment. However, in order not to suffer permanent damage, it is essential to be examined by a doctor and receive medical care. During treatment, the knee should not be loaded or only minimally loaded, if possible. If the health condition permits, locomotion can be done carefully and slowly. Daily physiotherapy exercises, performed in consultation with a therapist, help with recovery. Wearing healthy footwear is mandatory. The use of shoes with high heels or in the wrong sizes should always be avoided.In order not to subject the knee or leg to unnecessary stress, closed, comfortable and breathable shoes are recommended. In the case of a knee injury, compensatory movements are often made, which lead to an incorrect posture of the body. The affected person should ensure in good time that the healthy regions of the body are not subjected to excessive or one-sided loads. Compensatory movements are necessary with the aim of preventing muscle or bone damage. Everyday obligations should be restructured in the event of a knee injury so that relief can take place. Help from people close to the patient should be sought. It is also important for the affected person to pay attention to his or her emotional well-being.
