A320
Inflight Event / Encounter Wake Vortex Encounter
General Physical Injury / Incapacitation
Environment - Non Weather Related; Procedure
[We were] in cruise flight at FL350 near SAAGS waypoint in Kansas City airspace. Ride was smooth; no forecast or reported turbulence. Seat belt sign was off. No reported traffic by ATC in vicinity; and no TCAS targets in close proximity. Experienced a moderate jolt that lasted less than 2 seconds; and ride was back to smooth and remained smooth. Felt very much like crossing another aircraft's flight path and wake turbulence. First Officer reported wake turbulence encounter to ATC; Captain called the back to check on status of flight attendants and passengers. Initial response from purser was flight attendants were OK as were passengers. Approximately 10 minutes later; received a call from the cabin that flight attendants were NOT all OK; and one of the flight attendants in the back had hurt her back and was in significant pain. She was bent over in the aft galley at the time of the encounter. Captain spoke with injured Flight Attendant to ascertain her condition. She was not in acute medical distress to warrant a diversion; so the Captain elected to continue to [destination]. Immediately after; Captain began coordinating with Dispatch regarding the wake turbulence encounter and the injured Flight Attendant. Arrangements were made for medical to meet the aircraft. In-Flight and the station were also notified through Dispatch to coordinate for acquiring a third flight attendant for the continuation of the flight. Remainder of the flight was uneventful; and via altitude management avoided any turbulence and chop the remainder of the flight. Upon arrival we deplaned the passengers while the injured Flight Attendant was seated on the aft jump seat with ice on her back. The medical response team then entered the aircraft to attend to the injured Flight Attendant.
There were several aircraft above us in our immediate vicinity; but no contrails to visually indicate a potential wake. Additionally; there were no radio transmissions from other aircraft in our vicinity that indicated anything other than smooth rides in our vicinity.
A320 flight crew reported wake vortex encounter at FL350 that resulted in an injury to a flight attendant.