Wynonna's husband Michael Scott "Cactus" Moser's leg has been amputated following a weekend motorcycle accident in South Dakota. The surgery was announced Monday (Aug. 20) on the singer's website. Moser, 55, plays drums in his wife's band and achieved national success in the '80s as a member of the country band Highway 101. The couple were riding their Harley-Davidson motorcycles Saturday (Aug. 18) near Hill City, S.D., prior to a scheduled concert in Deadwood, S.D., when Moser drifted across the center line of the highway and collided with the driver's side door of an oncoming car. Wynonna was riding ahead of Moser and not involved in the accident. According to the singer's website, Moser's left leg was severed, and doctors in Rapid City, S.D., amputated the leg above the knee. He has also undergone surgery to his hand. Wynonna canceled Saturday's concert and four other dates scheduled this week in Canada.