Police in Normanton today released details of the incident, which happened in the Railway Terrace area of the town at around 5.30pm on November 2.
Despite increased neighbourhood team patrols in the area, the dog and its owner have not been identified.
PC Joshua Carter, of Wakefield East Neighbourhood Patrol Team, said: “The victim has suffered what look to be life changing injuries as a result of this incident and faces potential operations in years to come. It is vital that we identify and speak to the owner of this dog."
The victim had been walking her own dog towards the train station when a golden brown pit bull-type dog got away from its owner.
It knocked the victim to the ground, before attacking her dog.
The other dog’s owner then separated the two dogs before leaving the scene.
The 65-year-old suffered a shattered shin and broken knee cap as a result of the fall and is continuing to receive medical treatment for her injuries.
Police said the owner of the pit bull-type dog was described as white, around 5ft 10in and stocky, with short, brown hair. He was wearing work trousers and a polo shirt.
PC Carter said: “We are hoping that someone locally will know who this man is.
"The victim herself had seen him and his dog walking a similar route on previous occasions and it is likely that others will have also seen him around."
Anyone with information about the dog and its owner are asked to call Wakefield East Neighbourhood Patrol Team via 101, quoting reference 13170565887.