by Logan Swisher, PT, DPT, OCS


Osteoarthritis (OA) is the most common cause of disability in adults and it is estimated that 14 million individuals in the US have symptomatic knee OA.  Total knee arthroplasty (TKA) has been proven as an effective and cost-efficient intervention for end- stage knee osteoarthritis. Most people who undergo a TKA have marked improvements in function and reduction of pain compared to their preoperative condition, however, others have varied recovery of their functional abilities and not all patients experience significant improvements after surgery. The aim of this study was to examine if preoperative measures could predict functional ability at 1 year and 2 years after surgery.


-155 participants at initial evaluation

-155 participants at 1 year follow up

-125 participants at 2 years follow up


Measurements of participants age, height, weight, bilateral quadriceps muscle strength, knee flexion and extension range of motion, the Timed “Up and Go” test (TUG), stair-climbing task (SCT), and two subsets of the Knee Outcome Survey (KOS) which were the activities of daily living and pain subsets.


The TUG, SCT and KOS scores at 1 and 2 years showed significant improvement over the scores at the initial evaluation. A weak quadriceps muscle in the limb that did not undergo the surgery was related to poorer 1-and 2-year outcomes. It was also found that older participants with higher body masses also had poorer outcomes at 1 and 2 years.

Clinical Relevance

The study revealed the importance of rehabilitation regimens after TKA incorporating exercises to improve strength of the non-operated limb as well as treat the deficits imposed by surgery. If left untreated, weakness in the non-operated limb may continue to impede functional ability and result in poorer postsurgical outcomes. There should also be an emphasis on treating age-related impairment, such as poor balance and strength, and reducing body mass to help improve long-term outcomes. At Physical Therapy First, our physical therapists will perform a thorough 1-on-1, hour long appointment and work with you to create a plan of care that helps you reach your goals.


Zeni JA Jr, Snyder-Mackler L. Early postoperative measures predict 1- and 2-year outcomes after unilateral total knee arthroplasty: importance of contralateral limb strength. Phys Ther. 2010 Jan;90(1):43-54. doi: 10.2522/ptj.20090089. Epub 2009 Dec 3. PMID: 19959653; PMCID: PMC2802824