Total knee arthroplasty (TKA) is the most commonly
performed elective surgery in the United States. TKA
typically improves functional performance and reduces
pain associated with knee osteoarthritis. Little is
known about the influence of TKA on overall physical
activity levels. Physical activity, defined as “any bodily
movement produced by skeletal muscles that results
in energy expenditure”, confers many health benefits
but typically decreases with endstage osteoarthritis.
The purpose of this review is to describe the potential
benefits (metabolic, functional, and orthopedic) of
physical activity to patients undergoing TKA, present
results from recent studies aimed to determine the
effect of TKA on physical activity, and discuss potential
sources of variability and conflicting results for physical
activity outcomes. Several studies utilizing self-reported
outcomes indicate that patients perceive themselves
to be more physically active after TKA than they were
before surgery. Accelerometry-based outcomes indicate
that physical activity for patients after TKA remains at
or below pre-surgical levels. Several different factors
likely contributed to these variable results, including the
use of different instruments, duration of follow-up, and
characteristics of the subjects studied. Comparison to
norms, however, suggests that daily physical activity for
patients following TKA may fall short of healthy agematched
controls. We propose that further study of the
relationship between TKA and physical activity needs
to be performed using accelerometry-based outcome
measures at multiple post-surgical time points.