The knee joint is a critical component of the human musculoskeletal system since it plays a critical role in movement, stability, and weight-bearing functions. This being one of the most complex joints that exist in the body, this particular joint, particularly the internal structure, is very prone to injury and disorders. The term Internal Derangement of the Knee is used to describe a broad spectrum of conditions resulting from damage to internal elements of the knee, such as ligaments, menisci, articular cartilage, and the synovial membrane.These injuries usually have their origin in trauma or repetitive strain but can sometimes have an origin in degenerative conditions or other disease processes.
What is an Internal Derangement of the Knee?
The term Internal Derangement of the Knee refers to any damage or disorder to the inner structures of the knee joint. Although it is not a disease per se, internal derangement forms one term that implies an entire complex of pathologies caused by damage or malfunctioning of the anatomical constituents of the knee. Injuries may either be to soft tissues, such as the ligaments and menisci or hard tissues, like bone and cartilage.
Internal Derangements are most commonly associated as a consequence of traumatic causes such as falls, motor vehicle accidents, or direct sporting injuries; however, they can also result from chronic causes such as osteoarthritis or repetitive microtrauma.
This can be associated with instability and decreased mobility of the joint, accompanied by pain, and in some cases, long-term dysfunction unless it is treated properly; in appropriate cases of medical treatment, the situation may worsen, including degeneration of the joint, poor quality of life, and surgery.
Causes and Risk Factors of Internal Derangement of the Knee
Internal Derangement of the Knee may arise from acute injuries and some diseases that come with time. Some of the more common causes of this condition are as follows:
1. Trauma
The most common cause of Internal Derangement occurs in an athlete or a person who is prone to highimpact activities. One might receive a direct blow to the knee or abnormal twisting which can tear ligaments, damage the meniscus, or dislocate the kneecap. Such injuries often occur in sports like football, soccer, basketball, or skiing.
Fractures: fracture of the bone, most probably the femur, tibia, or patella, might displace the knee and even damage the internal structures, like cartilage or ligaments.
2. Degenerative Changes
Cartilage breaks down: Over time, continuous wear and tear may lead to cartilage breakage; this allows the bones to hurt each other, bringing along pain, inflammation, and limited mobility. Since cartilage starts breaking down, it can cause further friction on the bones and irritation on the menisci, ligaments, and the soft tissues in the knee.
Meniscal Degeneration: The meniscus is a cushion between the femur and the tibia. These can slowly degenerate due to degeneration, tear easily with internal derangement. Degenerative meniscal tears are often seen in old people, above the age of 50 years.
3. Repetitive Strain
Overuse Injuries: The knee joint often suffers from repeated stresses, such as the actions of running or jumping or squatting. Microtrauma can lead to deterioration in internal structures of the joint and may eventually cause patellar tendinitis, bursitis, or meniscal tears.
4. Congenital or Developmental Conditions
Joint Instability: A few are born with joint instability because of some anatomical differences or genetic conditions. Such induces the possibility of the knee being exposed to greater risks of injuries and internal derangements when there apparently seems to be no trauma.
Misalignment: Any form of deformity, such as knock-knees or bowlegs, could easily cause uneven pressure on the knee joint and subsequent derangements.
Common Types of Internal Derangement of the Knee
Internal Derangement of the Knee includes a broad spectrum of injuries and conditions of virtually every portion of the knee. The most common types of internal derangement include:
1. Ligament Injuries
ACL Tear : The ACL is a major stabilizing ligament in the knee. Tears or ruptures occur frequently during activities that include rapid changes in direction, sudden stops or jumps. An ACL rupture can cause instability of the knee and result in pain, swelling, and inability to bear weight on the joint.
Posterior Cruciate Ligament (PCL) Tear: The tears of PCL are less common than ACL injuries and result from a direct blow to the front of the knee, such as in a car accident or sports collision.
MCL and LCL Sprains: The MCL and LCL stabilize the medial and lateral aspects of the knee. Ligament sprains or tears, usually secondary to a blow directly to the medial or lateral sides of the knee, or secondary to twisting, result in pain and swelling, and decreased range of motion.
2. Meniscal Tears
Menisci are C-shaped cartilage structures that cushion the knee joint and also aid in shock absorption. Meniscal tears may be initiated by sudden twisting movements or the degenerative wear of slow processes. Often, they lead to a problem in performing regular everyday activities owing to unstable instability. Clicking or locking sensations may also be present.
3. Patella Injuries
Patella luxation: Here, the biomechanics may have been directly or indirectly affected by trauma. The results are typically painful, swollen, and sometimes temporarily immobilized.
Patellofemoral Pain Syndrome: This is secondary to abnormal motion of the patella within the femoral groove, an irritation and inflammation to the area. It can also occur due to overuse and poor alignment of the knee.
4. Joint Cartilage Damage
Articular cartilage on the surfaces of the femur, tibia, and patella can be damaged by either trauma or degenerative disease, such as osteoarthritis, to cause pain, stiffness, and swelling with eventual long-term degeneration of the joint.
5. Synovial Injuries
In some cases, the synovial membrane around the knee joint gets damaged, leading to inflammation, swelling, and pain. This may occur due to trauma or because of chronic conditions like rheumatoid arthritis.
Symptoms of Intenal Derangement of the Knee
The symptoms of an Internal Derangement of the Knee depend on the nature and severity of the injury; however, there are typical symptoms such as:
- Pain: Pain is the most common presenting symptom and can be mild to severe, depending upon the severity of the injury. It could be continuous or start with some definite movements of the knee, like twisting or bearing weight.
- Swelling: Swelling is also common when the knee joint is inflamed. Swelling can be immediate after an injury or experienced over time.
- Instability: Patients complain that the knee “gives way” or that they cannot bear weight through it, which is very typical in ligament injuries or meniscal tears.
- Reduced Range of Motion: Pain or stiffness in a joint can limit the normal range of motion-the ability of a knee to bend and straighten in a normal fashion.
- Locking or Clicking: Many patients also report the feeling of locking or clicking. This usually occurs when meniscal tears or loose pieces of cartilage are present within the joint.
Diagnosis of Internal Derangement of the Knee
A medical diagnosis of Internal Derangement of the Knee would normally start with a thorough physical examination. The physician would check the knee for swelling, tenderness, instability, and limited mobility. Special tests could then be applied to specifically study the structures in the knee, as in the Lachman’s test for an ACL injury or McMurray’s test for meniscal tears.
Imaging can be in the form of X-rays, MRI, or CT scans. These will enable the determination of the degree of injury. In most cases, X-rays are valuable in the diagnosis of a fracture or a dislocated joint. MRI on the soft tissues like the cartilages and ligaments gives much more visual detail and, therefore very important for the diagnosis of more subtle injuries such as tears of the meniscus or ligamentous damage.
Treatment Options in Internal Derangement of the Knee
The treatment for Internal Derangement of the Knee is greatly different according to the nature and degree of injury. It ranges from conservative, non-surgical measures to very invasive surgical procedures.
1. Conservative Management
- Rest and Ice: Most injuries to the knee that are the result of trauma should be treated with rest and ice to reduce swelling and irritation.
- Physical Therapy: Rehabilitation exercises designed to strengthen the knee-supporting muscles and also to ensure joint stability contribute to healing as well as prevent further injuries.
- Medication: Nonsteroidal anti-inflammatory drugs (NSAIDs) or any other analgesics may be prescribed to help manage the pain and inflammation.
- Bracing or taping: In low-grade ligament sprain or meniscal tears, another modality for providing support involves stabilizing the knee with a knee brace and supportive taping.
2. Surgical Management Arthroscopy
Minimally invasive, arthroscopy is used to treat a variety of meniscus tears as well as cartilage damage and certain ligament injuries. It involves the insertion of a small camera (arthroscope) through which the knee joint can be visualized and treated.
Ligament Reconstruction: In some cases, reconstruct the ligament in severe ACL or PCL tears, by using tissue obtained from the patient itself, termed autograft, or from a donor through an allograft. Meniscus