Bob Lutz no longer wears the ugly braces, flesh-colored elastic with steel supports, that used to encase his knees when he played tennis. All that remains of the injures that interrupted his promising career are the scars, which look like railroad tracks around both kneecaps.

"I have almost as much mobility as I used to. Every once in a while I'll lose some spring and feel a little slow off the mark, but maybe that's just the night before," he said yesterday, after dispatching Andre Pattision, 6-2, 6-4, in the first round of the $100,000 Volvo Classic at George Washington University's Smith Center.

Lutz, seeded sixth, looks like a good bet to get to at least the semifinals of this 32-man Grand Prix event. He is in the quarter of the draw vacated by No. 4 seed Roscoe Tanner, the Austratralian Open champ, who withdrew because of an attack of bronchitis.

Mark Edmondson, 22, the former janitor and odd-job man who won the Australian Open in the biggest upset of the 1976 season, ousted fellow Aussie Ray Ruffels yesterday, 6-4, 7-5.

John Whitlinger, 23, who took the place of former Stanford teammate Tanner, advanced to the second round by beating Brazilian Davis Cupper Tomaz Koch, 2-6, 7-6, 6-4.

If form holds, Lutz would meet top seed Bjorn Borg, the 20-year-old Wimbledon champion, in the semis. They played two weeks ago in the quarterfinals of the U.S. Indoors in Memphis, Borg winning, 6-1, 6-1.

Borg, who will be making his Washington debut, was due in town last night from Cleveland, where he gave a deposition in the suit that has been filed against him by World Championship Tennis for allegedly reneging on a commitment to play its circuit.

Borg is scheduled to play his first-rounder against Californian Hank Pfister tonight. He will likely be weary, having flown back to the U.S. Monday from South Africa, where he was supposed to play Guillermo Vilas in the final of a Grand Prix tournament that was rained out in Johannesburg.

Lutz, who has played only five tournaments this year and is coming off a week of surfing, golfing, and relaxing in the sun at his home in San Clemente, Cal., played alternately solid and sloppy tennis.

He breezed through the first set, attacking Pattison's more vulnerable forehand side, and kept the sturdy Rhodesian pinned to the backcourt with deep volleys and approaches.

In the second set, Lutz had a break point against Pattison 30-40 in the first game, two at 15-40 in the third game, three at 15-40 and one ad in the fifth game. Each time he let him off the hook with some ragged play.

Lutz let Pattison back to deuce from 15-40 in the seventh game, then finally broke him. He promptly lost his own serve to make it 4-4, then broke again at 15 and served out the match.

"It starts working on your mind when you have so many 15-40 games and can't win one point," Lutz said of all those missed opportunities. "That was frustrating, but overall I thought I was hitting the ball solidly. I'm pleased with the way I served and returned serve."

Lutz won the U.S. Pro title in 1972 and seemed ready to crack the upper-most echelon of the game until he ruptured a tendon in his right knee in July, 1973. He was out of action several months following surgery, and several months more after a similar operation on the left knee the next year.

The process of rehabilitation was slow and painful, but Lutz crossed a psychological barrier two summers ago when he discarded his knee braces.

"The doctor had told me to wear them only as long as the knees kept swelling and hurt when I played," he recalled yesterday. "They gradually get stronger. The right one still puffs up now and then, but generally they'-refine. I don't have to ice them after matches anymore."

Lutz has made a steady, if gradual, climb back in the world rankings and now holds the No. 12 position on the computer list of the Association of Tennis Professionals.

He is strong and fit at 5-11 and 182 pounds -- he has the physique of a football fullback, especially in the thighs and shoulders -- and says he is eager to play tennis again after taking his longest vacation since these postoperative layoffs.

He was runner-up to Vitas Gerulaitis in the Ocean City International last month, his first tournament in two months. Since then he has played the American Airlines Tennis Games, losing in the round of 16 to eventual champ Brian Gottfried, and Memphis, losing to eventual champ Borg.

Lutz said he thinks an occasional complete break from the game is good for players, especially ones who have been traveling the circuit as long as he has.

"There are so many tournaments and so much money out there, most guys go every week for the buck," he said. "They don't take time off to practice or to rest or to just get away.As a result, quite a few get stale, and there are more injuries and more guys getting tired of the game than ever before. You need a little R and R now and then."