Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.

Arthritis is the most common disease that affects bones in your knees. The cartilage in the knee gradually wears away, causing pain and swelling. Injuries to ligaments and tendons also cause knee problems. A common injury is to the anterior cruciate ligament (ACL). You usually injure your ACL by a sudden twisting motion. ACL and other knee injuries are common sports injuries.

Treatment of knee problems depends on the cause. In some cases your doctor may recommend knee replacement.

Source:
NIH: Medline Plus

Fluoroscopic-Guided Hyalgan Injection for Knee Pain

This non-operative, outpatient procedure is designed to provide relief for patients with arthritis of the knee. The technique allows the physician to inject the pain relieving drug Hyalgan with maximum accuracy.

Preparation
The physician swabs the knee, injects a numbing medication and positions a special X-ray device called a fluoroscope.

Injecting the Dye
To make sure the medicine injection gets to the space inside the joint, the physician first uses an injection of dye. The dye shows up on the fluoroscope image. If the dye pools in the soft tissue at the front of the knee, the physician adjusts the needle placement. When the dye reaches the target area – the space inside the joint – the physician is ready to inject the medication.

Injecting the Medication
The rear of the syringe is removed from the needle and a Hyalgan-filled syringe is attached. The physician injects the medication into the joint. The Hyalgan will bond with the fluid in the knee to cushion and lubricate the joint. A physical therapist will use rehabilitation procedures to enhance the effects of the medication.