The knee joint is composed of bone, cartilage, ligaments and fluid, and muscles and tendons help move the knee joint. According to the U.S. National Library of Medicine and the National Institutes of Health or NIH, damage to any of these structures can cause knee problems. Knee injuries can range from mild and annoying to severe and debilitating.
Inability to Bear Weight
The inability to bear either full or partial weight on one leg may be symptomatic of a knee injury. According to the Mayo Clinic, knee injuries that involve an inability to bear weight on the knee require the immediate attention of a health care professional. The Mayo Clinic website also states that a person's inability to bear weight on her knee following a knee injury suggests that one of the knee's four ligaments has been damaged. Knee ligament injuries, including sprains or ruptures, may occur to one or more of the following ligaments: the medial collateral ligament or MCL, the lateral collateral ligament or LCLC, the anterior cruciate ligament or ACL and the posterior cruciate ligament or PCL. The MCL is located on the inside aspect of the knee and the LCL is located on the outside aspect of the knee. The ACL and PCL are located within the knee joint. Injury to any of these ligaments can affect a person's ability to ambulate and perform daily activities.
Swelling & Inflammation
Swelling and inflammation of the tissues that compose the knee are common knee injury symptoms. According to the NIH, there are numerous conditions that cause knee swelling and inflammation, and they can themselves produce pain and exacerbate an existing condition. The Mayo Clinic states that the following types of knee injuries produce either knee swelling, inflammation or both: tendon injuries or tendinitis, meniscus or cartilage injuries, bursitis, a dislocated kneecap, Osgood-Schlatter disease, a hyperextended knee, septic arthritis, rheumatoid arthritis, osteoarthritis and gout and pseudogout. Swelling and inflammation associated with knee pain that's not severe or debilitating may be treated conservatively, at home, using rest, ice and elevation, along with anti-inflammatory medications. Mayo Clinic also recommends seeking professional health assistance if knee injury symptoms, including swelling and inflammation, have not improved within three to seven days post-injury.
Knee Pain or Discomfort
Knee pain or discomfort is felt by most people who experience a knee injury. According to the Sports Injury Clinic website, knee pain may be caused by overuse injuries, in which small stresses to the knee's tissues are repeated numerous times without a sufficient period of recovery. Overuse injuries are common in athletes, especially endurance athletes such as runners, jumpers and cyclists. The Sports Injury Clinic also notes that knee injury-related pain can be acute or immediate, which often occurs after impact or twisting injuries involving the knee. All types of tissue that compose the knee can be pain generators under the right circumstances, and knee pain can be felt on all aspects of the knee, including within the knee joint itself. Although knee injuries account for a significant amount of knee pain, knee pain can also be symptomatic of knee joint degeneration or systemic conditions that affect the knee.
