Tiser and trainer/driver Paul Campbell had just crossed the line to end a fastwork session when the filly stumbled and crashed to the track on her knees.

''We had just finished going over the line when she fell - the headcheck snapped and there was nothing keeping her up,'' Paul said.

Maree Campbell said Tiser had taken skin off both knees.

She said Tiser's nearside foreleg was of most concern with Bendigo Equine Hospital staff finding a penetration wound into the joint.

Surgeon Sarah Jalim operated on the joint on Tuesday.

''They place a cannula into the joint and pump fluid through - three litres of saline - to make sure there's no foreign bodies in there,'' Maree said.

''They administer large doses of antibiotics to stop infection. It's vital no infection gets into the leg - no matter how small the infection, if it gets in that can have grave consequences.''

Maree said Bendigo Equine Hospital surgeon Sarah Jalim reported the operation on Tiser's knee had gone as expected.

''They have placed a torniquet above the wound so they can administer higher doses of antibiotics,'' Maree said.

''She will stay in the hospital for two to three days so she can be monitored and her bandages can be changed - things like that. Provided there are no complications, and they don't think there will be any, she'll come home in a few days. 

''Knees can take a long time to heal but if everything goes well she should be back to full health in three months time.''

Don't miss Tiser's Race For Fun Club column in the Bendigo Advertiser on Tuesday to see what she has to say about the experience.