Natural history of uncorrected flexion contractures following total knee arthroplasty

Over a 2-year period, 29 patients were identified that had preoperative flexion contractures less than 30 degrees and were not fully corrected to neutral following total knee arthroplasty. They were followed after surgery at 3, 6, and 12 months, and yearly thereafter with complete clinical and roentgenographic examinations to determine the natural history of the flexion contracture and its effect on the clinical outcome. The mean age of the 10 women and 19 men was 66 years (range, 47-80 years). The mean preoperative flexion contracture was 11 degrees (range, 5 degrees-30 degrees). The mean follow-up period was 33 months (range, 24-60 months). The mean values of the flexion contractures at each follow-up period were; immediately after surgery, 10.5 degrees; at 3 months, 5 degrees; at 6 months, 2 degrees; at 12 months, 1 degree; and at 24 months, 1 degree (P < .0001). Resolution of the flexion contracture did not vary between patients under and over the age of 65 years. There was no statistically significant difference in the residual flexion contracture when knees with preoperative contractures from 0 degrees to 14 degrees and 15 degrees to 30 degrees were compared. The clinical outcome was not affected by the residual flexion contracture after 6 months of follow-up evaluations. Significant improvements can occur after surgery with rehabilitation, and it appears that complete intraoperative correction is not necessary. There appears to be no difference in the natural history of flexion contractures with regard to age or severity up to 30 degrees.