A knee injury can affect any of the ligaments, tendons or fluid-filled sacs( bursae) that surround your knee joint as well as the bones, cartilage, and ligaments that form the joint itself.
– ACL Injury – is a tearing of the anterior cruciate ligament, one of four ligaments that connect your shinbone to your thighbone. An ACL injury is particularly common in people who play basketball, go downhill skiing, because it’s linked to sudden changes in direction.
– Torn Meniscus– the meniscus is formed of tough, rubbery cartilage and acts as a shock absorber between your shinbone and thighbone. It can be torn if you suddenly twist your knee while bearing weight on it.
– Knee Bursitis -is an inflammation in the bursae, the small sacs of fluid that cushion the outside of the knee joint so that tendons and ligaments glide smoothly over the joint.
– Patellar Tendinitis – is irritation and inflammation of one or more tendons, — the thick, fibrous cords that attach muscles to bones. Runners, skiers, and cyclists are prone to develop inflammation in the patellar tendon which connects the quadriceps muscle on the thigh to the shinbone.
– Loose Body – Sometimes injury or degeneration of bone or cartilage can cause a piece of bone or cartilage to break off and float in the joint space. This may not create any problems unless the loose body interferes with knee joint movement—the effect is something like a pencil caught in a door hinge.
– Knee Locking – this can occur from a cartilage tear. When a portion of cartilage from the tear flips inside the knee joint, you may not be able to fully straighten your knee.
– Dislocated Kneecap – this occurs when the triangular bone (patella) that covers the front of your knee slips out of place, usually to the outside of your knee. You’ll be able to see the dislocation, and your kneecap is likely to move excessively from side to side.
– Hip or Foot Pain -if you have hip or foot pain, you may change the way you walk to spare these painful joints. But this altered gait can interfere with the alignment of your kneecap and place more stress on your knee joint. In some cases, problems in the hip or foot can refer pain to the knee.
– Osteoarthritis (degenerative arthritis) is the most common type of arthritis. It’s a wear and tear condition that occurs when the cartilage in your knee deteriorates with use and age.
– Rheumatoid Arthritis– the most debilitating form of arthritis is an autoimmune condition that can affect almost any joint in your body, including your knees. Although rheumatoid arthritis is a chronic disease, it tends to vary in severity and may even come and go.
– Gout – this type of arthritis occurs when uric acid crystals build up in the joint. While gout most commonly affects the big toe, it can also occur in the knee.
– Pseudogout – often mistaken for gout is caused by calcium pyrophosphate crystals that develop in the joint fluid. Knees are the most common joint affected by pseudogout.
– Septic Arthritis – an infection of your knee joint leading to swelling, pain, and redness. There’s usually no trauma before the onset of pain. Septic arthritis often occurs with a fever.
– Iliotibial band syndrome – occurs when the ligament that extends from the outside of your pelvic bone to the outside of your tibia becomes so tight (iliotibial band) that it rubs against the outer portion of your femur. Distance runners are especially susceptible to iliotibial band syndrome.
– Chondromalacia Patellae (patellofemoral pain syndrome) –is a general term that refers to pain arising between your patella and the underlying thigh bone (femur). It’s common in young adults, especially those who have a slight misalignment of the knee cap; in athletes, and in older adults who usually develop the condition as a result of arthritis of the kneecap.
– Osgood-Schlatter Disease – affects the softer area of bone near the top of the shinbone, where bone growth occurs. It’s more common in boys who play games or sports that involve running or jumping. The discomfort can last a few months and may continue to recur until the child’s bones stop growing.
– Osteochondritis Dissecans – is caused by a reduced blood flow to the end of a bone, it is a joint condition in which a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone. It occurs most often in young men, particularly after an injury to the knee.
Tests and Diagnosis
– X-ray – can help detect bone fractures and degenerative joint disease.
– Computerized Tomography (CT) scan – combine X-rays taken from many different angles, to create cross-sectional images of the inside of your body. CT scans can help diagnose bone problems and detect loose bodies.
– Ultrasound – is the use of sound waves to produce real-time images of the structures within and around your knee and how they are working. Your doctor may want to maneuver your knee into different positions during the ultrasound, to check for specific problems.
– Magnetic Resonance Imaging (MRI) – uses radio waves and a powerful magnet to create 3-D images of the inside if your knee. This test is particularly useful in revealing injuries to soft tissues such as ligaments, tendons, cartilage, and muscles.
If your doctor suspects an infection, gout, or pseudogout, you’re likely to have blood tests and sometimes arthrocentesis, a procedure in which a small amount of fluid is removed from within your knee joint with a needle and sent to a laboratory for analysis.