Participation in Adults Post Total Knee Replacement · Boston University Slideshow Title Goes Here Center for Enhancing Activity and Participation among Persons with Arthritis (ENACT)

Participation in Adults Post

Total Knee Replacement

Jessica Maxwell, PT, DPT, OCS

Boston University

College of Health and Rehabilitation Sciences: Sargent College

Boston University Medical Center

Boston University Slideshow Title Goes Here

Center for Enhancing Activity and Participation among Persons with Arthritis (ENACT)

Learning Objectives

Review the prevalence and incidence of knee

replacements in the U.S.

Present the current evidence on knee

replacement outcomes aside from participation

Present current evidence on participation

outcomes after knee replacement

Discuss future areas for research



Background

Rates of total

knee replacement

skyrocketing

Over 3.5 million

annually in U.S.

by 20301

Figure adapted from, 1Kurtz, 2007



Significance of Increased knee

replacement utilization

Projected annual costs of $49 billion by 20151

Increase from $14.6 billion in 2004

JAMA- 2012: Need for increased study and tracking of health outcomes of knee replacement2

Public health concern

1Kim, 2008; 2Slowver, et al; JAMA 2012



What do we already

know about knee

replacement outcomes?



How are knee replacement

outcomes measured?

Outcome Tools:

Western Ontario McMaster Osteoarthritis Index

(WOMAC)

Late Life Disability Index (LLDI)

Thresholds of change or status:

Minimal Clinically Important

Difference/Improvement (MCII)1

Patient Acceptable Symptom State (PASS)2 Escobar et al, 2007; Escobar et al, 2012



PAIN

Overall there is a significant reduction in pain

after knee replacement1

Approximately 50% in first year

Persistent Pain

Systematic review of 11 studies

approximately 20% of patients have long-term

persistent pain2

1 Bachmeier, 2011; 2Beswick, et al, 2012



PHYSICAL FUNCTION

Improvement in physical function occurs after

knee replacement1

Systematic review of 62 studies

Mean improvement of 28/100 points on WOMAC

1Kane et al, 2005;



PHYSICAL FUNCTION

Persistent physical function limitations

Estimates range from 10-30% of patients

21% at 2 years following knee replacement1

71% met the Patient Acceptable Symptom State for

function after knee replacement2

Study of patient satisfaction found 81% satisfied

with functional activities3

1Singh et al 2010, 2Maxwell et al, in submission; 3Bourne et al, 2010



But what about PARTICIPATION?



Participation matters to knee

replacement patients Patient concerns about participation status increased

throughout the 6 week period following knee

replacement1

Considering return to these roles (going shopping,

participating in hobbies…)

Items related to participation (driving, walking

outdoors) ranked among the highest in

importance among subjects pre- and 6 months

post-knee replacement2

1Rastogi et al, 2008 2Wright et al, 2010



How is knee replacement related to

participation?

George et al (2008) studied ADL and IADL

changes

Knee replacement group and knee osteoarthritis

group

E.g. IADLs: preparing meals, housework, shopping

Knee replacement group improved while the non-

knee replacement group declined

Performing personal shopping: improved 6% for knee

replacement subjects, vs. 1.7% decline for OA subjects



How is knee replacement related to

participation?

Davis et al (2011) found mean improvements

in participation among those with knee

replacement

Measured participation with LLDI and Calderdale

Community Mobility Scale

Subjects improved in participation 27% from 3 to 12

months post-knee replacement

Pre-knee replacement participation influenced post-

knee replacement participation

Improvement in participation occurred later than

improvements in pain and function



Do people with knee replacements experience

participation restrictions?

As with pain and function, there appears to be

an improvement in mean participation.

Is there similarly a proportion of subjects that

are experiencing participation restrictions after

knee replacement?



OARSI, 2012

Frequency and Predictors of Participation

Restriction

Following Knee Replacement

Maxwell JL1, Keysor JJ1, Neogi T1, Niu J1, Nevitt

MC3, Singh J3, Frey-Law L4, Felson DT1

1Boston University, Boston, MA; 2University of

California, San Francisco; 3University of Alabama,

Birmingham; 4University of Iowa, Iowa City



Prevalence of Participation

Restrictions

To explore the prevalence of home and

community participation restrictions among

persons at least 1 and 2 years after a knee

replacement.



MOST Study

3026 persons recruited from community in

Iowa and Alabama with risk factors for knee

osteoarthritis

Clinic visits at 0, 30, 60, 84 months

Subsample of subjects with knee replacement

at least one year prior to assessment of

participation

LLDI- Instrumental subscale of the Limitation

domain used to measure participation

Considered score of <69/100 to have participation

restricted



Study Sample Subjects’ demographic and ≥ 1 year post-knee replacement clinical

factors (n=218)

Maxwell, et al, OARSI, 2012



Prevalence of Participation Restriction Proportions of subjects with participation restrictions pre- knee replacement and

post- knee replacement

% of Subjects with Participation

Restrictions

Independent Variable Pre-knee

replacement

(n=218)

≥ 1 year post-knee

replacement

(n=218)

p-value

Total 37 31 p=.12

Sex: Women 39 32 p=.26

Men 32 25 p=.25

Race: White 33 28 p=.29

Other 62 41 p=.13

Age at knee replacement:

<65 years 46 29 p=.007

65-74 years 33 30 p=.56

75+ years 24 44 p=.13




Prevalence of Participation Restriction Proportions of subjects with participation restrictions pre- knee

replacement and post- knee replacement % of Subjects with Participation

Restrictions


replacement

(n=218)

≥ 1 year post-knee

replacement

(n=218)

p-value

Total 37 31 p=.12


Men 32 25 p=.25


Other 62 41 p=.13


<65 years 46 29 p=.007

65-74 years 33 30 p=.56

75+ years 24 44 p=.13





replacement and post- knee replacement


% of Subjects with Participation

Restrictions


replacement

(n=218)

≥ 1 year post-

knee

replacement

(n=218)

p-value

Total 37 31 p=.12


Men 32 25 p=.25


Other 62 41 p=.13


<65 years 46 29 p=.007

65-74 years 33 30 p=.56

75+ years 24 44 p=.13




replacement and post- knee replacement

% of Subjects with

Participation Restrictions


replacement

(n=218)

≥ 1 year post-

knee

replacement

(n=218)

p-value

Total 37 31 p=.12


Men 32 25 p=.25


Other 62 41 p=.13


<65 years 46 29 p=.007

65-74 years 33 30 p=.56

75+ years 24 44 p=.13



Conclusions-Prevalence of

participation restrictions

Non-Whites have a higher proportion of participation restrictions pre-knee replacement than Whites

The youngest subjects had somewhat higher proportions with participation restrictions pre-knee replacement, and their post-knee replacement participation restrictions was significantly lower.

Older subjects report less participation restrictions pre-knee replacement but have increased % of participation restrictions after knee replacement




What is driving these restrictions?

What demographic

and clinical factors

are associated with

participation

restrictions among

persons with a knee

replacement at least

1 year earlier?



Does Age Matter?

Subjects with


pre-knee replacement:

Not Participation

Restricted

Post-knee replacement

Participation

Restricted Post-knee

replacement

Age < 65 55 45

Age 65-74 45 55

Age 75+ 50 50



Prevalence Ratios of post- knee replacement

participation restriction


Independent Variable Unadjusted, PR (95%CI) Adjusted PR (95% CI)‡

Sex (ref=men) 1.6 (0.8, 3.0) 1.8 (0.7, 2.7)

Race (ref= White) 2.0 (0.9, 4.4) 1.9 (0.8, 4.5)

Age at knee replacement: < 65 yrs. (n=92) Reference Reference

65-74 (n=101) 1.0 (0.5, 1.9) 1.1 (0.6, 2.1)

75+ (n=25) 1.9 (0.8, 4.7) 2.2 (0.9, 5.7)

Educational Attainment (ref=>HS) 1.4 (0.4, 4.5) 1.2 (0.4, 4.0)

Depressive Symptoms (ref≤16) 4.9 (2.2, 11) 4.5 (2.0, 10.3)

Quadriceps Strength: strongest tertile Reference Reference

middle tertile 1.1 (0.5, 2.3) 1.0 (0.5, 2.3)

weakest tertile 1.4 (0.6, 3.0) 1.3 (0.6, 2.8)

Post-knee replacement pain in the

ipsilateral (knee replacement) knee (ref

<10/20)

5.1 (1.8, 14.4) 7.0 (2.2, 22.7)

Post-knee replacement pain in contralateral

knee (ref <10/20)

5.6 (1.9, 16.8) 5.3 (1.6, 16.9)

Number of knees replaced (ref=1) 1.0 (0.5, 1.9) 1.0 (0.6, 2.0)

Body Mass Index (ref < 30) 1.1 (0.6, 1.9) 1.1(0.6, 2.1)

Pre-knee replacement WOMAC Physical

Function

1.1 (1.0, 1.1) 1.1 (1.0, 1.1)

Comorbidities 1.1 (0.9, 1.3) 1.0 (0.8, 1.3)



Conclusions-Predictors of participation

restrictions after knee replacement

Depressive symptoms

Pain in either knee

Oldest age group?

Potential Intervention targets?



Limitations

Cross Sectional

Quantitative analysis may not fully inform us about the reasons for participation restriction in this patient population. Need to assess other factors not included in

measurement tools or measured at clinical visits

Limited to those with knee replacement. Can’t determine effect of knee replacement on participation without a comparison group



The Effect of Knee Replacement on

Participation Restrictions: The Multicenter

Osteoarthritis Study

Maxwell JL1, Niu J1, Yang T1, Keysor, JJ1, Neogi T1, Nevitt MC2, Singh J3,

Frey-Law L4 and Felson DT1 1Boston University, Boston, MA; 2University

of California, San Francisco; 3University of Alabama, Birmingham;

4University of Iowa, Iowa City

Maxwell, ACR, 2012



Aims

Determine whether the proportions with

participation restrictions are similar among

knee replacement subjects and a matched

group of people without knee replacement

Determine the effect of knee replacement

status on participation as compared to a group

with symptomatic OA but without knee

replacement



Methods

We compared those with knee replacement to

a matched group of persons with symptomatic

knee OA (SxOA) using propensity score

methods to reduce confounding by indication

Estimates probability of each subject of having a

knee replacement, given their covariates

Increase similarity between two groups

1Maxwell, et al, ACR, 2012



Demographic and pre-index clinical variables by

knee replacement status group

Variable

Unmatched Whole Sample (Crude) Propensity Score** Matched Sample

knee replacement

subjects (n=267)

Non- knee

replacement subjects

(n=1255)

knee replacement

subjects (n=237)*

Non-knee

replacement

subjects (n=237)

Age, years, mean

(SD)

67.9 (7.6) 66.5 (8.1) 68.0 (7.6) 67.7 (7.9)

% Female 69 64 68 70

% White 87 80 88 87

BMI, kg/m2, mean

(SD)

32.6 (7.0) 32.1 (6.5) 32.1 (6.6) 32.2 (6.5)

Depressive score,

range 0-16, mean

(SD)

8.4 (7.6) 8.5 (8.5) 7.7 (6.8) 8.8 (9.1)

% with ≤ 1

Comorbidity

82 83 82 85

Knee pain, range

0-20, mean (SD)

7.71 (3.8) 5.6 (3.9) 7.3 (3.6) 7.3 (3.8)

WOMAC Function,

mean (SD)

27.1 (11.4) 20.8 (12.6) 26.1 (10.9) 27.1 (12.1)

% with

Participation

Restrictions

37 32 34 35



Results

Knee Replacement

Subjects (n=113)

Non- knee

replacement SxOA

Subjects (n=113)

Propensity Score

matched sample

70% 63%

Proportions with ≥ 12 month post-index date




No difference between groups

The knee replacement subjects had the same

odds (OR 1.0, 95% CI 0.6,1.7) of participation

restriction as the propensity-score matched Sx

OA subjects.



Limitations

Timing between pre-knee replacement and

surgery and post-knee replacement and

surgery differs and may be lengthy

Caution interpreting proportions with

participation restrictions in SxOA group, as

these are matched to knee replacement group

and thus have more severe symptoms



Conclusions of Matched Study

Knee replacements do not necessarily

decrease the risk of participation restrictions

among persons with symptomatic knee

osteoarthritis.

One year may not be long enough follow-up

time to assess participation restrictions among

persons with knee replacement



Unclear Evidence

Other studies provide evidence that participation

improves1,2

Does this achieve outcome thresholds?

MOST data suggests that participation may get worse

in some subjects

Appears that pre-knee replacement participation

status influences post-knee replacement participation

status2,3

Depressive symptoms, knee pain and age may be

factors associated with participation restrictions3

Evidence is unclear and needs to be looked at further


So where do we go next? Ms. Jones Mrs. Smith

60 years old

RA 20 years; good

medication control

Chronic mild-moderate

pain

Ambulate ½ mile

Works part time

Rarely leaves her home

▫ 60 years old

▫ RA for 20 years; good

medication control

▫ She has chronic mild-moderate

pain

▫ Ambulation limited to ¼ mile

▫ Employed

▫ Participates 2-3 times/week in

community activities



Intervention for Participation

Limited evidence on rehabilitation programs

post-knee replacement

Those which exist address pain and physical

function

Need for more research on improving

participation or decreasing participation

restriction among persons post-knee

replacement



Where are we and what’s next?

Knee replacements will occur at staggering rates

Growing evidence that participation restrictions are

common after knee replacement

Beginning to explore factors associated with

participation restrictions in this group of patients

Area for increased focus of research



Acknowledgements

David Felson, MD

Michael LaValley, PhD

Jingbo Niu, ScD.

Tianzhong Yang, MS

Julie Keysor, PT, PhD.

Funding for this project was provided by the American College of

Rheumatology Research and Education Foundation Rheumatology

Scientist Development Award



Thank you! Questions?

Documents

Participation in Adults Post Total Knee Replacement · Boston University Slideshow Title Goes Here Center for Enhancing Activity and Participation among Persons with Arthritis (ENACT)