Louis-Etienne Gayet, an orthopaedic surgeon at the University Hospital Centre in Poitiers, central France, was called in to help eight-year-old Kwanza after the ape snapped her thighbone at Vallee des Singes (Valley of the Apes) in Romagne.
The break occurred very close to where the thighbone, or femur, enters the hip, where its ball-like end is enclosed by a ring of bone, the park said in a press release on Friday.
The problem was that, because the femur had been completely fractured, the ball end twisted around in the hip casing. As a result, the two bones were left back-to-front.
Delicate cases such as these are relatively common in human surgery but almost unheard-of for veterinarians.
Gayet rolled up his sleeves and in a three-hour operation at a veterinary clinic last Monday gently turned the bone's ball end in the right direction and reattached it to the rest of the femur with a 15-centimetre (six-inch) plate, along with an eight-cm (3.5-inch) screw in the hip.
There was a stroke of luck because Kwanza, still youthful in gorilla terms, has the same femur anatomy as a human adult, which meant Gayet could fix a standard plate which he uses in his day-to-day patients.
The neck of a femur in a young gorilla forms a boney crook of about 130 degrees. In adult gorillas, the angle is about 100 degrees, Gayet explained.
Kwanza can now crawl around, but it will take another six weeks to know whether the bones have knitted properly and she has recovered full mobility.
"It was a fantastic experience," Gayet said in an interview with AFP, before wondering aloud: "I don't know -- has anyone ever fixed a fracture of the neck of a femur on a gorilla before?"
