Knee braces used by high-school and college football players are for the most part ineffective in preventing even the most common knee injuries and may actually aggravate others, orthopedic surgeons warned last week.

Despite protective claims by some brace manufacturers, "so far studies have shown no consistent decrease in the rate of injury for players wearing prophylactic knee braces," said Dr. David Drez, immediate past chairman of the American Academy of Orthopedic Surgeons Committee on Sports Medicine.

"We cannot wholeheartedly recommend their use, especially in preventing the most common type of football knee injury -- tears of the anterior cruciate ligament."

Knee braces are commonly used in college and high-school football, particularly by interior linemen and linebackers, in the belief they will prevent or reduce injuries caused by damage to the ligaments -- tough bands of tissue holding bones together. The most common football knee injury is a tear to a cross-shaped ligament near the front of the knee -- the anterior cruciate.

In an official policy statement, the surgeons' group said scientific studies have failed to consistently show a protective effect for any brand of knee braces, and some studies suggest the devices may actually aggravate certain injuries.

Drez also questioned the cost of the devices -- about $35 per brace -- plus the cost of adhesive tape and a trainer's time for each application.

One study showed that if every high-school football player were required to wear a knee brace, the cost would exceed $69 million a year. In contrast, the cost of treating all high-school-football knee injuries is only about $55 million.

Drez suggested that school boards and football coaches could better spend money used for braces on training of the players and educating of coaching and trainers, as well as improving the quality of the playing fields, a contributing factor in many football injuries.