Starting on the afternoon of Day 0 (the day of surgery), pain on active range of motion (ROM) of the operated knee will be measured using an 11 point numerical rating scale (NRS) each morning at 8 AM ± 2 hours and each afternoon at 3 PM ± 3 hours, not within one hour after physical therapy. In addition, if the subject ambulates, pain with ambulation will be measured during the first ambulation in the morning and during the first ambulation after noon. Subjects will complete the Brief Pain Inventory - Short Form (BPI-SF) preoperatively, and at the 2, 6, and 12 week visits. Subjects will be questioned regarding the use of assistive devices (cane, walker, wheelchair, bedside commode, or other assistive devices) at screening, at discharge, and at the 2, 6, and 12 week visits. The active ROM on flexion of the knee, measured using a goniometer, will be recorded at screening and at the 2 week visit. Sensory mapping of the knee will be performed at screening and at the 12 week visit.