Treadmill Perturbation Training for Fall Prevention After Total Knee Replacement

The goal of this clinical trial is to learn about preventing falls in people who have total knee replacement surgery using treadmill perturbation training. Perturbation training involves adjusting to rapid speed changes on a treadmill. The main questions it aims to answer are:

* Does perturbation training improve the way that people who are planning to have total knee replacement surgery recover after treadmill test that reproduces a trip to the front or side?
* Does perturbation training reduce the incidence of preventable gait-related falls during the first year after total knee replacement?

Participants will:

* complete surveys about their condition and fall history and take part in testing of walking ability and balance.
* have a baseline gait analysis test to measure the motion of their body during normal walking.
* Be randomized into two groups. One will receive fall-prevention literature. The other will receive the same literature and then take part in a two-week treadmill perturbation training program.
* be contacted every two weeks for one year, and asked questions about whether they have fallen during that time.
* wear an activity monitor on their wrist for one week periods, every three months.

Researchers will compare the number of falls from the group that received literature to the treatment group to see if the training group has fewer falls during the year after surgery.

Participants:

We will recruit 378 participants who are scheduled for primary unilateral total knee arthroplasty (TKA) and can commit to 4 additional study visits.

Baseline assessment: At enrollment, all participants will be assessed for a set of demographic and functional risk factors listed below

1. Age
2. Sex
3. Body mass index
4. Number of painful joints
5. Use of opiate pain medication
6. Number of falls in the past 12 months
7. Self-reported activity level (UCLA activity score)
8. Habitual walking speed (8-meter walk test)
9. Functional Limitations

   1. PROMIS (Patient-Reported Outcomes Measurement Information Systems) Physical Function computerized adaptive test (CAT)
   2. Knee Injury and Osteoarthritis Outcome Score (KOOS) Activities of Daily Living Subscale
10. Pain - KOOS pain subscale
11. Balance and mobility impairment

    1. Timed up and go test
    2. 30 second chair stand test
    3. 4 stage balance test
    4. 40 m fast paced walk test
    5. Stair climb test
    6. 6-minute walk test
12. Comorbidities - Charlson comorbidity index
13. Depression - PROMIS depression (CAT)

In addition, physical activity level will be measured for 7 days following the baseline test using accelerometers. Participants will wear the monitor for 7 days and then will return it in a postage-paid express mail envelope that we will provide. After assessment, randomization assignments will be provided, written education materials will be provided (fall prevention brochures from the Centers for Disease Control and Prevention), and the following activities will be undertaken according to grouping:

Group 1 - Perturbation training (4 sessions over 2 weeks):

1. 30 reflective markers will be placed on bony landmarks of the trunk, arms, and lower extremities with one marker indicating the proximal and distal end of each segment and one marker placed out of line with the other two so that the motion capture software can define the 3D motion of each segment.
2. Participants will be stand comfortably with feet at approximately hip width, on a split belt treadmill. They will be fitted with a safety harness. They will be instructed that the treadmill will move and that they should do whatever they can to maintain or regain their balance.
3. During the next one minute, a tester will activate the treadmill. Two small surface translations (0.02 cm at roughly 0.22 m/s) will then be administered which will require several small forward directed steps to regain stability. These two small disturbances will provide a familiarization of how the treadmill works.
4. Participants will be informed that they will receive 21 disturbances of larger magnitude. They will be instructed to "do whatever \[they\] can to recovery \[their\] balance".
5. On the next perturbation, the participant will receive a larger disturbance. Each sagittal plane training perturbation will consist of the treadmill accelerating to 1.25 m/s in 300 ms, maintaining a constant velocity for 170 ms, then decelerating to 0 m/s in 100 ms. Prior to the disturbance participants will be informed to recover their balance and continue walking for 5 seconds after the perturbation. The first disturbance constitutes the baseline test.
6. The tester will then administer 20 more disturbances of the same magnitude. This constitutes the training protocol.
7. A final perturbation will be administered. This constitutes the post-test assessment.
8. Steps 2-7 will be repeated with the participant turned 90 degrees such that a step to the side will be required. The magnitude of the perturbations will be scaled to 2 foot widths.
9. Step 8 will be repeated with the participant turned by 180 degrees such that both sides receive lateral training.

Group 2 - Education Control: this group will not undergo additional training but will only receive the written materials

At the end of the baseline visit, participants will coordinate their preferred contact method with the study coordinator (i.e. phone, email, text). Beginning one week after surgery and then every two weeks for one year, participants will be contacted by a research assistant, who will be blinded to the participant's group assignment, and asked whether they had fallen during the previous two weeks.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of endstage knee osteoarthritis requiring total knee arthroplasty (TKA). TKA scheduled within two months and able to schedule the required training visits prior to surgery.

Exclusion Criteria: Potential participants will be excluded if they have dizziness or self-reported medical conditions that would be expected to affect walking and balance. These specifically include history of stroke, multiple sclerosis, Parkinson's disease, and balance disorders including positional vertigo and Meniere's disease. Other exclusion criteria include plans to undergo a contralateral TKA within 12 months or history of other lower extremity joint replacement within 5 years. Finally, people who report idiopathic low back pain, history of heart disease, uncorrected vision impairment, or institutionalization will be excluded.

-