Dr. Stanford Lavine, an orthopedic surgeon and team physician for the Redskins and the University of Maryland, has had a significant reduction recently in his major knee-operation caseload.

The reason: arthroscopic surgery.

Coy Bacon, the Redskins' veteran defensive end, had a knee operation last season. Six days later, he was back in the starting lineup without missing a game.

The reason: arthroscopic surgery.

A patient of Lavine's had a conventional major knee operation years ago that required a two-week stay in the hospital and eight months of rehabilitation. After more surgery several years later, performed by Lavine, the man was playing racquetball four days later.

The reason: arthroscopic surgery.

"People have heard about it and now they are asking for it," Lavine said. "They usually call it microsurgery, but they know one thing. It works."

The breakthrough over the last five years in the use of the arthroscope has revolutionized the diagnosing and repairing of injured knees. And it has had a major impact on organized sports and on the weekend athlete whose knees suddenly are subjected to increased wear.

The need for major surgery has been reduced considerably. And the arthroscope allows doctors to determine much more accurately the extent and location of an injury, instead of having to rely heavily on more general X-rays.

"Hurting a knee now doesn't necessarily mean operating as much as it did before," Lavine said. "I went through a three- to four-month period recently where I didn't do one major (conventional) knee operation. Everything was performed through the scope. Then Had a string of two or three conventional operations.

"But coaches should love it. They can get their athletes back faster. And now we can leave the knee more intact than by opening it up like in the past. If I'm a patient, I think I would like to hear that."

The arthroscope resembles a long, very narrow metal tube with a magnifying lens at one end. First used in the 1920s, it didn't become popular until smaller size and developments in fiber optics (transmission of light and magnification) made it more practical and dependable.

The surgeon inserts the arthroscope into the knee through an incision about an inch wide. By looking into the scope, he can examine much of the knee area and, by inserting one or two other small instruments in other tiny holes, he can operate. More sophisticated models, costing $8,000 or more, magnify what is seen through the scope onto a television screen in the operating room.

In many cases, a local anesthetic is used. The incision normally is covered with a common compression bandage, not closed with stitches. Lavine says most patientsd are walking the same day and are out of the hospital sometimes within 24 hours. Conventional knee operations necessitate a week or two in the hospital and the patient isn't allowed to walk for days.

"You don't have the pain that you get with regular knee surgery and the rehabilitation is much, much faster," he said. "The reaction to surgery is a lot less traumatic, too.

"First and foremost, however, the scope's major benefit is for diagnosing injuries. We can get right in there and look around for ourselves. We can clean out floating bodies and we pinpoint where the damage is. There is no more guessing in knee surgery. And it cuts down the number of unnecessary operations

"We were taught in medical school that, for example, you take out all the cartilage if we thought it was ripped. Now we just take out the torn part. We realize that leaving in the cartilage is vitally important for the future of the knee."

Cartilage helps stabilize the knee, and it prevents the knee from locking. By removing all the cartilage, the chance of future problems with arthritis is enhanced.

The knee never was meant to be tackled and blocked. Although it can be rotated a bit, it basically is limited to a hinge-like motion of extension and flexion.

Although there are numerous knee injuries, the two most common in athletics are torn cartilage and torn ligaments. Meniscus cartilage is located between the femur and tibia, and acts as a cushion or shock absorber. Articular cartilage covers the ends of the femur and tibia (upper and lower leg bones, respectively), enabling them to move smoothly. Four ligaments (anterior and posterior cruciate, lateral and medial collateral) bind and brace the knee, which has no stability of its own. The ligaments prevent the knee from moving too far either from side to side or up and down.

"In the old days, let's say you had a twisted knee which didn't swell but you had pain on the inside of the knee," Lavine said. "We'd probably take out all the meniscus to fix it.

"Now with the arthroscope, we can look in and see if there is just a slight tear to the meniscus. If that's the case, we can repair it using the scope and leave most of the meniscus intact.Before you couldn't see as much even by making a major incision. You could't see or get to the small tear in this manner."

The arthroscope is less effective dealing with ligament tears, which aren't as frequent as cartilage problems among athletic knee injuries, but are more apt to end careers.Cartilage damage can be caused by a twisting motion; ligament damage can result from the knee being hit from the side on a block or tackle. Frequently, players will put off cartilage surgery until after the season; ligament repair must be done immediately.

"If there is a significant ligament tear, you have to perform conventional surgery," Lavine said."But you can use the scope to look at the tear first. If you can determine that it is a partial tear, then you might decide not to operate but to try rehabilitation instead. Before, you might not have been able to see it, and the chance of an operation was more frequent."

The most difficult ligament problem for athletes involves the anterior cruciate, or front, ligament. The arthroscope has helped improve the diagnosis when the ACL is torn.

"Usually when you hear about a basketball player feeling his knee pop, it involves the ACL," Lavine said. "Before you would draw the blood out of it and then put it in a cast for six weeks or more. The leg would develop atrophy and would have to be built back up along with the rehabilitation of the knee.

"Now, you scope the knee, see if the tear needs to be operated on or if you can treat it in another fashion. You can make a more significant judgment sooner this way."

Last year, two Redskin tackles, Fred Dean and George Starke, had partial ligament tears. Neither had surgery. Instead, their injuries were healed through the use of cast braces. Both were ready to play within four weeks. Five years ago, they might have been sidelined for the season if an operation had been performed.

The cast brace, normally a plastic mold that is fitted to the contour of the leg with a hinge at the knee, allows the patient to use the knee in normal walking fashion while restricting any side to side movement. The tear is allowed to heal undisturbed, but the leg muscles are not restricted, as would be the case were the leg in a plaster cast.

"The plaster cast turns the leg into putty," Lavine said. "You come out of a cast and your thigh, let's say, has lost an inch. Well, you have to build that up before you can play again, and that takes time.

"With the cast brace, the atrophy is reduced dramatically. Teams don't lose players for long periods and rehabilitation is much easier."

The less the knee is disturbed, the easier rehabilitation becomes -- and the less chance for major arthritic problems in the future.

"It used to be that when a ligament was torn and surgery was needed, it might take eight months to get the knee right again," said Bubba Tyer, Redskin trainer. "You took everything very slow because you didn't want to disturb the tissue while it was healing."

Tackle Terry Hermeling ruptured his patella (kneecap) ligament hitting a blocking sled in 1974.He looked down at his leg and his kneecap, freed when the ligament snapped, was floating in his thigh. Tyer had to use his pickup truck to cart him off the field.

Hermeling was out for more than a year. During his rehabilitation, he snapped the ligament again, requiring additional major surgery. He says that at least twice during his long ordeal, he was ready to quit football.

Now, after four knee operations and 12 years in the league, Hermiling is getting the first indications of arthritis.

"You can feel it in the mornings when it is damp or raining," he said. "It is stiff and score a lot of times too. And after we practice on the artificial turf, well, you can feel it for days.

"I know I'm going to have knee problems the rest of my life. It's something I just have to live with. But I like to play so I made a decision a long time ago to put up with my injuries."

Hermeling's knees, thanks to his willpower and careful treatment, are now as healthy as they ever will be. If the arthroscope had been perfected earlier, he might have been spared some of the permanent damage. Still, he can leg-squat 500 pounds with those knees.

"Every time I see him pushing that much weight, I cringe a little," Tyer said. "All I can see is the knee going again and another ligament snapping. Considering what he has been through, I'd hate to see that happen again."