Twenty-five patients underwent isolated Ilizarov femoral lengthenings (mean lengthening, 6 cm). A retrospective review of the charts showed the specific changes in knee range of motion (ROM) during lengthening, after removal of the frame, and at the final follow-up examination. A decrease in ROM was seen during lengthening to an average minimum of 37 degrees +/- 15 degrees. Toward the end of the consolidation phase, improvement to 69 degrees +/- 28 degrees was noted. A progressive increase in ROM was seen after frame removal. Mean preoperative flexion was 127 degrees +/- 16 degrees, and at follow-up flexion was 122 degrees +/- 23 degrees (p = 0.191). Of the five patients who did not achieve 120 degrees flexion at the final follow-up examination, three had a diminished ROM (average, 107 degrees) at the outset. Two patients lost more than 15% of their preoperative flexion. There was no correlation noted between worst ROM (during lengthening) and final ROM at the last follow-up examination.