Poorer performance preoperatively on the Six-Minute Walk Test (6MW), Stair Climbing Test (SCT), and Timed Up and Go Test (TUG) was related to poorer performance in the same measure after total knee arthroplasty (TKA), say authors of a study designed to develop a preliminary decision algorithm predicting functional performance outcomes to aid in the decision of when to undergo TKA. Age and decreased mental health were secondary predictors of poorer performance at 6 months on the TUG and SCT, respectively. These measures may help further develop models that predict thresholds for poor outcomes after TKA, the authors add.

One hundred and nineteen patients undergoing primary unilateral TKA were evaluated before and 6 months after TKA. A regression tree analysis using a recursive partitioning function was performed with TUG time, 6MW distance, and SCT time as measured 6 months after TKA as the primary outcomes. Preoperative measures of functional performance, joint performance, anthropometrics, demographics, and self-reported status were evaluated as predictors of the primary outcomes 6 months after surgery.  

Individuals taking 10.1 or more seconds on TUG and aged 72 years or older before surgery had the poorest performance on TUG 6 months after surgery. Individuals walking less than 314 meters on 6MW before surgery had the poorest performance on 6MW 6 months after surgery. Individuals taking 17 or more seconds to complete SCT and scoring less than 40 on the SF-36 mental component score before surgery had the poorest performance on SCT 6 months after surgery.

APTA member Michael J. Bade, PT, is lead author of the article, which is published in Journal of Orthopaedic Research. APTA members Joseph A. Zeni, PT, PhD, Jennifer E. Stevens-Lapsley, PT, MPT, PhD, and Lynn Snyder-Mackler, PT, ScD, SCS, FAPTA, are coauthors.