Amy Scott, 35, took her shoes off before she walked up to her victim in a stairwell at the New Premier Pub in Ashington, Northumberland, and pushed her from behind.
Newcastle Crown Court heard the 33-year-old suffered an "explosive fracture" in her wrist and banged her head during the tumble that left her unconscious at the bottom of the stairs.
Prosecutor Jolyon Perks told the court the injured woman, who needed an operation on her wrist and five months off work, has little recollection of what happened on January 25 last year but the attack was caught on CCTV.
Mr Perks said: "The defendant takes her shoes off and walks toward the complainant and immediately pushes her from behind, forcefully, down the stairs.
"It is not the case that this defendant was unaware of what she had done because after pushing her she then stands and watches as the complainant falls down the entire length of the stairwell.
"As she reaches the bottom four steps she loses her balance and pitches forward and strikes her head on the floor. That renders her unconscious and the momentum of her body at the same time broke her wrist."
Mr Perks added: "It was nothing more than the defendant taking the opportunity of slyly pushing the complainant in the back when she wasn't looking or expecting it."
The court heard Scott then went back to her group of friends and put her shoes back on and waited for the police to arrive.
In a victim statement, the injured woman said she was left "sad and scared" by what happened and has been told that despite her wrist injury healing, she is now at higher risk of arthritis as she gets older.
Scott, of Bothal Terrace, Ashington, Northumberland, pleaded guilty to causing grievous bodily harm.
Mr recorder Dapinder Singh QC sentenced her to eight months imprisonment, suspended for 12 months, with 150 hours unpaid work and £500 compensation order.
The judge told her: "You removed your shoes and pushed her downstairs.
"As a result, the complainant received a broken writs and knock to the head and required an operation."
He added: "There is genuine remorse from you for what you have done and I accept this is highly out of character, especially as you are now 35 and a person of previous good character."
Mark Harrison, defending, said the attack was not premeditated and Scott was being "offered outside for a fight" by the victim.
Mr Harrison said Scott had "panicked" when she reached the stairwell and realised there were no doorman around.
He added: "It was a moment of madness, a moment she immediately regretted."
Mr Harrison said Scott, who is in employment and has recently returned to work after a period of furlough, had called for an ambulance and waited at the scene.