Competence of the extensor mechanism is the major determinant of functional outcome of patients after proximal tibia resection. A method of secondary reconstruction of the extensor mechanism using the middle third of the quadriceps tendon and the patellar retinaculum augmented with Gore-Tex strips and gastrocnemius flap is described. Between 1981 and 1997, 7 patients with extension lag greater than 20 degrees at least 1 year after the initial surgery underwent secondary reconstruction of the extensor mechanism. All patients were followed up for a minimum of 2 years. Full extension to an extension lag of 10 degrees was achieved in three patients, and an extension lag between 10 degrees and 20 degrees was achieved in 4 patients. All patients had good to excellent functional outcomes and reported no limitations in daily life activities.