Diagnosis and Treatment of Specific Types of Knee Injuries

Muscle Tendon Injuries

Almost all of these strains are treated with ice, elevation and rest. Sometimes compression with an ace wrap or knee sleeve is recommended, and crutches may be used for a short time to assist with walking. Ibuprofen can be used as an anti-inflammatory medication.

The mechanism of injury is either hyperextension, in which the hamstring muscles can be stretched or torn, or hyperflexion, in which the quadriceps muscle is injured. Rarely with a hyperflexion injury, the patellar or quadriceps tendon can be damaged and rupture. This injury is characterized by the inability to extend the knee and a defect that can be felt either above or below the patella. Surgery is required to repair this injury.

MCL and LCL Injuries

These ligaments can be stretched or torn when the foot is planted and a sideways force is directed to the knee. This can cause significant pain and difficulty walking as the body tries to protect the knee, but there is usually little swelling within the knee. The treatment for this injury may include a knee immobilizer, a removable Velcro splint that keeps the knee straight and keeps the knee stable. RICE (rest, ice, compression, and elevation) are the mainstays of treatment.

ACL Injuries

If the foot is planted and there is force applied from the front to back to the knee, then the cruciate ligaments can be damaged. Swelling in the knee occurs within minutes, and attempts at walking are difficult. The definitive diagnosis is difficult in the emergency department because the swelling and pain make it hard to test if the ligament is loose. Long-term treatment may require surgery and significant physical therapy to return good function of the knee joint.

Mensicus Tears

The cartilage of the knee can be acutely injured or can gradually tear. Acutely, the injury is of a twisting nature where the cartilage that is attached to and lays flat on the tibia is pinched between the femoral condyle and the tibial plateau. Pain and swelling occur gradually over many hours (as opposed to an ACL tear which swells much more quickly). Sometimes the injury seems trivial and no care is sought, but chronic pain occurs over time. There may be intermittent swelling, pain with walking uphill or climbing steps or giving way of the knee that results in near falls. History and physical examination often can make the diagnosis and MRI may be used to confirm it.

Fractures

Fractures of the bones of knee are relatively common. The patella, or kneecap, may fracture due to a fall directly onto it or in car accidents, when the knee is driven into the dashboard. If the bone is pulled apart, surgery will be required for repair, but if the bone is in good position, a knee immobilizer and watchful waiting may be all that is required.

The head of the fibula on the lateral side of the knee joint can be fractured either by a direct blow or as part of an injury to the shin or ankle. This bone usually heals with little intervention, but fractures of this bone can have a major complication. The peroneal nerve wraps around the bone and can be damaged by the fracture. This will cause a foot drop, so do not be surprised if the physician examines your foot when you complain of knee problems.

With jumping injuries, the surface of the tibia can be damaged, resulting in a fracture to the tibial plateau. Since this is where the femoral condyle sits to move the knee joint, it is important that it heals in the best position possible. For that reason, after plain x-rays reveal this fracture, a CT scan is done to make certain that there is no displacement of the bones. Occasionally this type of fracture requires surgery for repair.

Fractures of the femur require significant force, but in people with osteoporosis, less force is needed to cause a fracture of this large bone. In people with knee replacements who fall, there is a potential weakness at the site of the knee replacement above the femoral condyle, and this can be a site of fracture. The decision to operate or treat by immobilization with a cast will be made by the orthopedist.

Bursa Inflammation

Housemaid's knee (prepatellar bursitis) is due to repetitive kneeling and crawling on the knees. The bursa or space between the skin and kneecap becomes inflamed and fills with fluid. It is a localized injury and does not involve the knee itself. Treatment includes padding the knee and using ibuprofen as an anti-inflammatory medication.

Patellar Injuries

The kneecap sits within the tendon of the quadriceps muscle, in front of the femur, just above the knee joint. It is held in place by the muscles of the knee.

The patella can dislocate laterally (toward the outside of the knee). This occurs more commonly in women because of anatomic differences in the angle aligning the femur and tibia. Fortunately, the dislocation is easily returned to the normal position by straightening out the knee, usually resulting in the kneecap popping into place. Unfortunately, physical therapy and muscle strengthening are needed to prevent recurrent dislocations.

Patello-femoral syndrome occurs when the underside of the patella becomes inflamed if irritation develops as it rides its path with each flexion and extension of the knee, and it does not track smoothly. This inflammation can cause localized pain, especially with walking down stairs and with running. Treatment includes ice, anti-inflammatory medication, and exercises to balance the quadriceps muscle. More severe cases may require arthroscopic surgery to remove some of the inflamed cartilage and realign parts of the quadriceps muscle.