Sagittal Knee Gait Changes After Medial Unicompartmental and Total Knee Arthroplasty: An Exploratory Analysis of 32 Patients

Background: This study aimed to investigate postoperative developments of sagittal knee gait in a population of knee arthroplasty patients randomized to either unicompartmental or total knee arthroplasty. We hypothesized that knee arthroplasty patients develop greater walking speeds, range of motion, sagittal knee angle velocities, and sagittal knee angle accelerations.

Methods: Thirty-two patients were recruited from a randomized trial comparing the two implant types. Sagittal knee gait was examined preoperatively and at four and 12 months postoperatively. The examination used inertial measurement units. Nine gait parameters were defined focusing on knee angles, angular velocities, and accelerations.

Results: Stride frequency increased by 0.2 s^-1. Walking speed increased by 0.3 m/s. The range of motion increased by 7 degrees. Extension and flexion velocity during knee swing increased by 72 and 49 degrees/second. Acceleration during flexion increased by 565 degrees/second². Acceleration during extension increased by 1168 degrees/second². Acceleration after heel strike increased by 1549 degrees/second².

Conclusion: We observed significant developments in sagittal knee gait after knee arthroplasty. Patients developed faster walking speed and greater stride frequency, as well as improvements in the range of motion, sagittal knee angle velocities, and accelerations.