Diseases & Conditions

Diseases and conditions of the knee

Information is crucial to getting you back to your normal life. At Fountain Valley Regional Hospital and Medical Center, we provide you with up to date information on the latest orthopedic diseases and conditions affecting the knee. 

Below you’ll find information on common orthopedic conditions that we may treat. 

ACL injury

Spraining or tearing the anterior cruciate ligament, commonly referred to as the ACL, is one of the most common knee injuries. While people who participate in high-impact sports — such as basketball, soccer and football — are more prone to injuring their anterior cruciate ligaments, ACL injuries can happen to anyone.


Arthritis is a common medical term that refers to the inflammation of a joint, including the knee. The injury is accompanied by stiffness, swelling and pain. While there are more than 100 different forms of arthritis, osteoarthritis and rheumatoid arthritis are the most common types.

Collateral or combined ligament injuries

Knee ligament sprains or tears are common sports injuries. Any sort of direct contact to the knee or sudden change in direction can cause injury to the knee ligament. Injured ligaments, also referred to as sprains, are graded on a severity scale from 1 to 3, with 3 being the most severe and complete tear of the ligament.

Fractures of the distal femur (thighbone)

When a fracture or bone break occurs above the knee joint, it is referred to as a distal femur or thighbone fracture. The distal femur is where the bone flares out like an upside-down funnel.

Fractures of the proximal tibia (shinbone)

When a fracture or bone break occurs below the knee joint, it is referred to as a fracture of the proximal tibia, or shinbone. The proximal tibia is the upper portion of the bone where it widens to help form the knee joint.

Growth plate fractures

Children are still growing, which makes them prone to a unique injury called a growth plate fracture. A growth plate is an area of cartilage near the end of a bone. Since growth plates are the last part of a child’s bones to ossify or harden, they are very vulnerable to fractures.

Meniscal tear

An extremely common knee injury, a meniscal tear occurs when the cartilage in the knee is ruptured. While anyone can suffer a meniscal tear, it commonly affects athletes – particularly those who play contact sports.

Patellar tendon tear

Tears to the patellar tendon occur where the tendon attaches to the kneecap. Tears are generally classified as either partial or complete. In a complete tear, the tendon is separated from the kneecap, making it difficult to straighten the knee.

Patellar tendonitis (jumper’s knee)

This injury is characterized by inflammation of the patellar tendon, which connects the kneecap to the shinbone. The condition is commonly referred to as jumper’s knee, because it typically is caused by frequent jumps on hard surfaces. That leads to overuse of the knee joint.

Patellofemoral pail syndrome

This broad term is used to describe pain in the front of the knee and around the kneecap (patella). This injury can occur in non-athletes, although it most commonly affects people who participate in sports — specifically young adults and females. Therefore, this injury is often called runner's knee or jumper's knee.

Quadriceps tendon tears

The quadriceps tendon attaches the quadriceps to the kneecap. When the quadriceps tendon tears, straightening the leg is painful. Tears to the quadriceps tendon can be either partial or complete. This injury is most common in middle-aged adults who run, jump or participate in sports.

Posterior cruciate ligament injury

Located in the back of the knee, the posterior cruciate ligament is one of several ligaments that connect the thighbone to the shinbone. Symptoms of a torn posterior cruciate ligament include knee pain and swelling, stiff knee, difficulty walking and an unstable knee that feels like it may collapse.

Shin splints

This injury often occurs after a sudden change in physical activity, such as increasing the level of exercise done each week. Shin splints occur when the muscle and bone tissue in the leg become overworked by repetitive activity. Other factors can contribute to shin splints, including improper footwear or abnormally rigid arches.

Stress fracture

A stress fracture is considered one of the most common injuries in sports — with the most susceptible people being those participating in tennis, track and field, gymnastics and basketball. Typically, a stress fracture occurs when muscles become fatigued, are unable to absorb added shock and then transfer that shock to the bone. This causes a tiny crack in the bone, also known as a stress fracture.

Unstable kneecap

When a kneecap (patella) works properly, it rests in a groove at the end of the thighbone. When the knee bends, the patella moves within the groove. During a hard blow or fall, the patella slides too far to one side or the other, causing a complete or partial dislocation that is also known as an unstable kneecap.

Let Fountain Valley connect you with a physician

Call ​(855) 226-3744 or use our Find A Physician tool to be connected to an orthopedic specialist who can answer your questions. You can also read more about diseases and conditions in our Health Library.