Knee Injuries 

QUESTION:  I hurt my knee playing softball last summer and, even though the swelling gradually went down, there is pain when I twist on the knee or squat, and the knee will swell after this. Sometimes it even feels like the knee sticks or locks up. What have I done?

ANSWER:  The most common cause of pain, swelling, and locking after a knee injury is damage to the meniscus cartilage. The meniscus acts like a washer between the upper and lower bones of the knee. With normal knee motion, the meniscus moves a small amount in the joint. If a load-and-twisting motion occurs (turning on a planted foot or standing from a deep squat with a heavy load), the cartilage can be trapped between the bones and tear. This is usually associated with a stabbing pain at the joint line, difficulty straightening the knee (locking), and swelling that develops over several hours. Persistent pain, catching, swelling during activities (and stiffness following), despite rest and rehabilitation, are very suggestive of a cartilage tear. A physical examination, that reproduces the pain at the joint line or with load and twist of the joint, and a history of a load/sheer injury almost always indicates cartilage damage. Routine X-rays will not show the meniscus but may show other bony joint problems. An MRI may assist in diagnosis but rarely changes recommendations based on a good history of injury and physical exam.

If pain and swelling prevent participation in physical activities, surgery is recommended and is usually done as an arthroscopy (a technique where a small fiber-optic scope connected to a video camera allows the joint to be inspected and surgical instruments are then placed in small incisions to remove or repair the torn meniscus). Recovery usually requires several weeks to allow swelling to resolve and for recovery of strength, but most individuals can expect to return to the pre-injury level of activity.

WRITTEN BY: Thomas K. Miller, M. D.