Prehabilitation Using Aquatic Exercise

With aging population, total knee arthroplasty is performed with increasing frequency.
Although the surgery is successful in general, significant number of patients suffers
persistent pain and disability. Traditional risk assessment tool have been focused on single
organ systems. Our investigators have found that mobility, assessed by the Mobility
Assessment Tool short form (MAT-sf), is a simple and accurate method to predict postoperative
outcome, including length of stay, postoperative complications, and nursing home placement
for older patients. Prehabilitation is the process of enhancing a person's functional
capacity to withstand an incoming stressor. Although multiple studies have tested
prehabilitation before joint replacement surgery, results have been mixed. The investigators
hypothesize that patients with limited mobility are most likely to benefit from
prehabilitation. The investigators plan to use individualized aquatic exercise as a
prehabilitation tool to enhance compliance; the resistance of water strengthen muscle and
increasing energy expenditure; the buoyancy of water provides environment where the joints
are not weight bearing. The aims of the study are: 1) To evaluate the feasibility of
prehabilitation using 6-8 weeks of aquatic exercise in 40 geriatric patients who are
scheduled for total knee arthroplasty for osteoarthritis; 2) To examine the effects of 6-8
weeks of aquatic exercise on mobility, pain, stiffness, physical function, cognitive function
and depression; inflammatory markers and 3) To estimate the effect of prehabilitation on
postoperative outcomes. The investigators plan to enroll 40 patients age >50, who are
scheduled for elective primary total knee replacement. Investigators will screen patients in
the Preoperative Assessment Clinic and enroll patients who have decreased mobility, measured
by MAT-sf. Patients will be randomized into either a prehabilitation group or a usual care
group. All the participants will undergo extensive assessment on their pain, stiffness, and
physical function, depression, balance and cognitive function using the Western Ontario and
McMaster Universities Osteoarthritis Index (WOMAC), the expanded Short Physical Performance
Battery (eSPPB), and Montreal Cognitive Assessment (MoCA). Serum inflammatory markers will be
assessed at the baseline. The prehabilitation group will undergo 6-8 weeks of individualized
aquatic exercise in a heated pool (60 min/session, 3 times per week). Aquatic equipment maybe
used to challenge balance and trunk stabilization. All participants will be reassessed
immediately before surgery and 4 weeks after the surgery using WOMAC, eSPPB, MoCA and MAT-sf.
Serum inflammatory markers and body composition will be reassessed at the same time points.
The primary outcome of interest is will be postoperative complications, length of stay,
Intensive Care Unit length of stay, and institutionalization. If successful, investigators
will have sound pilot data for several critical health outcomes with which to support an
external proposal for a larger-scale study.