This report is an atempt to investigate the results of three operated cases which had been untreated for the anterolateral rotatory instabilities of the knee. The roentgenograms of these cases revealed slight joint space narrowing before the operation. The first, case, a 27-year-old female with normal leg alignment, showed satisfactory results after four years follow-up period inspite of roentgenographic deterioration. The second case, a 31-year-old femamale with varus deformity, had the additional osteotomy below the tibial tuberosity becaus of pain and swelling two years later. The third case, a 26-year-old feamale with varus deformity, had been complaining of occasional pain and swelling of the operated knee for three years after the operation.
