Definition: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: Maquet recommended 2-2.5 cm of anterior tibial tubercle elevation for patients with symptomatic osteoarthrosis of the patellofemoral joint. Fifty-three patients with osteoarthrosis were divided into three groups. The first 12 patients were treated by the classical Maquet procedure; 11 were totally relieved of patellofemoral pain, but there was one failure and five complications. In the second group of 32 patients, the patella was realigned within its groove to alter tracking of the patella to the proximal femoral condyles when necessary. Fish-mouthing technique and insertion of a drain after surgery were done. After a two-year follow-up examination, there were two failures and five complications. A third group of nine patients was treated with Ferguson's modification of Maquet's operation using a 1.25-cm tibial tubercle elevation through a transverse incision; two of the nine had complications, subsequently treated successfully by converting Ferguson's operation into the Maquet operation, as modified for Group II. The modified Maquet procedure can be an effective and reliable treatment of patellofemoral arthrosis with a relatively low incidence of complications.

Osteoarthritis