Greater amounts of weight-bearing asymmetry (WBA) 1 month after total knee arthroplasty (TKA) are predicted by modifiable factors, including habitual movement pattern and asymmetry in quadriceps and hamstrings strength, say authors of an article published online in Gait & Posture. 

Fifty-nine people were tested preoperatively and 1 month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit-to-Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations.

WBA, measured as the ratio of surgical/nonsurgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD) 1 month after TKA. Regression analysis identified preoperative WBA, quadriceps strength ratio, and hamstrings strength ratio as factors predictive of WBA 1 month after TKA (R(2)=0.30).

APTA member Cory L. Christiansen, PT, PhD, is lead author of the article. APTA members Michael J. Bade, PT, and Jennifer E. Stevens-Lapsley, PT, PhD, are coauthors.