Background: Following total knee arthroplasty, some patients who fail to achieve >90° of flexion in the early perioperative period may be considered candidates for manipulation of the knee under anesthesia. The purpose of this study was to assess the outcomes of manipulation following total knee arthroplasty.

Methods: One hundred and thirteen knees in ninety patients underwent manipulation for postoperative flexion of =90° at a mean of ten weeks after surgery. Flexion was measured with a goniometer prior to total knee arthroplasty, at the conclusion of the operative procedure, before manipulation, immediately after manipulation, at six months, and at one, three, and five years postoperatively.

Results: Eighty-one (90%) of the ninety patients achieved improvement of ultimate knee flexion following manipulation. The average flexion was 102° prior to total knee arthroplasty, 111° following skin closure, and 70° before manipulation. The average improvement in flexion from the measurement made before manipulation to that recorded at the five-year follow-up was 35° (p < 0.0001, paired t test). There was no significant difference in the mean improvement in flexion when patients who had manipulation within twelve weeks postoperatively were compared with those who had manipulation more than twelve weeks postoperatively. Patients who eventually underwent manipulation had significantly lower preoperative Knee Society pain scores (more pain) than those who had not had manipulation (p = 0.0027).

Conclusions: Manipulation generally increases ultimate flexion following total knee arthroplasty. Patients with severe preoperative pain are more likely to require manipulation.

Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.