LUCKLESS Western Bulldog Clay Smith has undergone a successful operation to repair his right anterior cruciate ligament for a third time.

Smith had his operation on Tuesday, when AFL.com.au understands his surgeon Dr David Young used a quadriceps tendon to reconstruct his ACL.

Smith again sidelined with knee injury

In more than 80 per cent of traditional knee reconstructions, hamstring tendons are used to replace the ruptured ACL, with patella tendons the next most common choice.

Leading sports medico Dr Peter Larkins told AFL.com.au that while quadriceps tendons were infrequently used, they were a perfectly acceptable alternative in traditional knee reconstructions.

Larkins said a quadriceps tendon had been used in Smith's latest operation, because a hamstring graft was not an option given tendons from the midfielder's right and left hamstrings were used in his first two reconstructions.

"The quadriceps tendon, which is the big very strong tendon just above the knee, is one of the other options when the hamstrings aren't available or the surgeon prefers to use something other than the patella tendon," Larkins said.

"The quadriceps tendon is an infrequently used alternative to a hamstring or patella tendon, but is still an accepted way to do it within sports surgery."

Larkins said Dr Young had extensive experience using quadriceps tendons in knee reconstructions.

Smith's recovery time will not be affected by the use of a quadriceps tendon, according to Larkins, with the former Gippsland Power player likely to be sidelined for the standard 10-12 month period that follows a traditional knee reconstruction.

Smith was playing his third senior game back from his second reconstruction when his right knee buckled as he landed awkwardly midway through the second quarter of the Bulldogs' loss to St Kilda last Saturday.

The Bulldogs medical staff diagnosed that Smith's grafted ACL had ruptured in that incident but, at the player's behest, allowed him to return to the ground when his knee gave way 15 minutes later as he was leading for the ball in the Dogs' forward 50.

Smith first ruptured his ACL in round 16, 2013.

He returned to the Bulldogs' senior team in round 10, 2014, but injured his shoulder in that game and was sidelined for five weeks.

After returning in the VFL, Smith ruptured his ACL for the second time in his third game back with the Bulldogs' VFL team.