Step descent strategy is altered bilaterally despite unilateral muscle strength impairment after total knee arthroplasty

Changes in Mediolateral Postural Control Mechanisms During Gait After Total Knee Arthroplasty

BACKGROUND

Patients who have total knee arthroplasty (TKA) likely suffer from decreased postural stability because of postoperative changes in musculoskeletal structure and loss of proprioception. The purpose of this experimental biomechanical study was to determine if patients who have TKA improve their dynamic postural control during walking after TKA as compared with before TKA. The secondary purpose was to assess changes in postural control between post-TKA patients and healthy controls.

METHODS

Twenty-three patients who had primary knee osteoarthritis scheduled to undergo unilateral or bilateral TKA were prospectively enrolled. Each patient was tested at 3 months, 6 months, and 12 months after TKA. Ten healthy controls matched for age, sex, and body mass index were selected from a database of previous healthy volunteers without knee osteoarthritis. Ten Vicon cameras and four AMTI force platforms were used to collect the marker and center of pressure (COP) data while participants performed gait.

RESULTS

Initial improvement in the double stance ratio was found by 6 months after TKA compared with before TKA. Patients showed improved postural control as evidenced by a faster mediolateral COP velocity and decreased double stance ratio at 12-month post-TKA compared with pre-TKA (P < .05). However, patients who underwent TKA exhibited limited ability to maintain consistent COP movement during walking with increased variability in COP parameters as compared with controls (P < .05).

CONCLUSION

Patients exhibited improvement in dynamic postural control after TKA with time, but had higher variability in COP parameters during gait than controls. It is possible that therapy aimed to improve proprioceptive balance after TKA may improve dynamic postural control.