Gibernau is currently lying 12th in the overall rider standings

But the 33-year-old will still miss the season-ending Valencia MotoGP on 29 October after crashing out in Portugal.

Gibernau crashed out of the Estoril race after clashing with Casey Stoner.

The Spaniard has had a poor season and has not yet agreed a new deal with Ducati as speculation mounts that his place could be taken by Stoner in 2007.

Stoner moved up to MotoGP at the start of the year and has claimed one podium finish.

The 21-year-old is currently seventh in the rider standings and is expected to be replaced at LCR Honda by Spaniard Carlos Checa.

Gibernau, who spent several weeks on the sidelines earlier this season with a broken collarbone, had the stem cell procedure at the San Jose hospital in Madrid.

"The results obtained with this technique on patients with weakened bones and repeated fractures have so far been very satisfactory," said Dr Angel Villamor.

"The operation, which avoids the immobilisation of the traumatised limb, went well."

The Valencia race will witness the climax to the duel between Valentino Rossi and Nicky Hayden for this year's world title.

Five-times MotoGP and 500cc champion Rossi enjoys an eight-point advantage over Hayden at the top of the standings after his second place in Portugal.

The American failed to finish the race after crashing out when Honda team mate Dani Pedrosa skidded into him as the two riders entered a bend trying to chase down Rossi.