Knee injury. Most common are sprain, strains of supporting structures such as the muscles, tendons (structure which attaches muscle to bone), ligaments (structure which connects bone to bone)., contusions which are bruises of the bones. Most of these can be treated with conservative measures, ice, rest, compression, gentle exercise.
Sprains/meniscus. Knee sprains and meniscal tears are most common. The major ligament injury is the ACL tear.
Overuse injuries. The most common reason for knee pain are not traumatic injuries, but overuse injuries. These can cause patellofemoral pain or anterior knee pain, it band syndrome and patellar tendinitis. Meniscus tears are also common and can be casued by trauma or happen atraumatically. Ligament tears (mcl and acl most commonly) are caused by traumatic injuries.
Sprain, strain, tear. Knee sprains, muscles strains and tears of the internal cartilage/meniscus are the most common knee injuries. The medial collateral ligament (mcl) is the most commonly sprained ligament. The hamstrings are the most strained muscle group, and the meniscus and articular cartilage can often sustain tears that require arthroscopy intervention (surgery).
Patellar pain. Otherwise known as pain or dysfunction of the tracking of the kneecap.
Overuse injuries. Knee injuries such as patellar tendinitis, meniscal tears, cartilage injury, and arthritis can lead to painful swollen knees in runners.
ACL tear in women. Women see significant numbers of acl tears from soccer but ligament stretch injuries are common, muscle strains are common and meniscus tears are also seen.
Not sure. Depending on what part of the country (north or south - longer or shorter warm periods for outside sports), there may be seasonal peaks but I would await an orthopedist for an answer as they specifically deal with the injuries.
No. Knee injuries are common year round. In the winter, many ski related injuries involve the knee, and so do falls on ice and snow. In summer, people are more active, thus, leading to more knee injuries.
No. They happen all year long.
Pain. Mostly front part of knee pain. Do not run, use other non-impact exercises.