In patients who have primary unilateral knee arthroplasty, as rehabilitation visits increased there was a direct association to improved interlimb weight-bearing symmetry when squatting to 60 degrees, say authors of an article in American Journal of Physical Medicine & Rehabilitation. 

For this study, the percentage of body weight placed over both limbs during stand and 30- and 60-degree squats in 38 patients (25 women and 13 men) who had primary unilateral knee arthroplasty was determined. An asymmetry index was used as a marker that could discriminate between patients who perceived at least moderate difficulty with functional tasks and those who perceived only slight or no difficulty with functional activities based on the physical function dimension of the Western Ontario McMaster Universities Osteoarthritis index approximately 1 week after surgery. Stepwise regression was conducted to determine whether clinical characteristics predicted weight-bearing asymmetry at discharge.

At initial visit (first observation), compared with the uninvolved side, individuals placed significantly less body weight over the involved or operated limb for stand and 30- and 60-degree squats. Results were similar at last rehabilitation visit (second observation). Identifying at least moderate self-reported difficulty with functional tasks based on the receiver operator characteristic curve for the asymmetry index for the stand position was 0.64, whereas for the 30- and 60-degree squats, the area under the curve was 0.81 and 0.89, respectively. At discharge from rehabilitation, there was a moderate to good direct relationship (r = 0.70) between the number of rehabilitation visits completed and the weight-bearing asymmetry index for the 60-degree squat.

APTA member Mark D. Rossi, PT, PhD, CSCS, is the article's lead author. APTA members Thomas Eberle, PT, DPT, DMT, FAAOMPT, Denis Brunt, PT, EdD, Marlon Wong, PT, DPT, OCS, MTC, and Matthew Waggoner, PT, DPT, MTC, are coauthors.