1694 - Do Rheumatoid Arthritis Patients Expect Less From Total Knee Arthroplasty?

Monday, November 7, 2011: 5:45 PM
W196b (McCormick Place West)
Hassan Ghomrawi1, Lisa A. Mandl2, Beverly Johnson2, Michael Alexiades2 and Susan M. Goodman2, 1Weil-Cornell Medical College, NYC, NY, 2Hospital for Special Surgery, New York, NY
Presentation Number: 1694

Background/Purpose: RA patients undergoing TKA often do not achieve the same functional results as osteoarthritis (OA) patients, yet are surprisingly satisfied. Satisfaction is determined not just by absolute improvements in pain and function, but also by fulfillment of pre-operative expectations. It is unknown if RA patients have different expectations compared to similar OA patients.

Method: RA patients undergoing TKA were compared to OA patients matched for age, gender, and lower extremity activity (LEAS) score.  All were drawn from a prospective institutional registry, patients with previous arthroplasties were excluded. Expectations were assessed using  the validated Hospital for Special Surgery Expectations Survey (see Table 1).  A composite score is calculated; range: 0-100; 100=highest expectations.  Preoperative data collection also included level of education, living situation, WOMAC, VAS for pain, ED-5Q, SF-36. Wilcoxon Signed Ranks test with Bonferroni correction was used to compare individual expectation items and T-test for mean expectations score.

Result: 62 RA patients were identified and matched to 124 OA controls. 87.1% were women, average age was 64.7±9.7 years, and average LEAS was 8.7±3.1 (range 2-17), which corresponds to being able to walk around the house and for several blocks without assistance. Other differences were statistically but unlikely clinically significant (See Table2).  There was no difference in living status or education. RA patients had a significantly lower expectations score than OA patients (mean 73.7 vs. 79.8 (p-value=0.03); a difference >6 is clinically meaningful. Scores on multiple individual expectations items were also lower for RA patients, but with a Bonferroni correction only statistically significant for two ( SeeTable 2). In addition, RA patients had lower ED-5Q scale scores suggesting RA patients place a lower value on their current health state. 

Conclusion: Compared to matched OA patients, RA patients had clinically meaningful differences in overall expectations prior to TKA.  They also had lower expectations for multiple individual items, and also placed lower value on their pre-operative heath state. This may explain the discrepancy between higher satisfaction and lower functional outcomes in RA patients. In the anti-TNF era, RA patients may be inappropriately accepting poorer outcomes.  This raises the possibility they may not be optimizing their post-surgical outcomes.

  Table 1 Comparisons of Pre-operative Expectations in OA vs. RA

 

OA Controls

Wilcoxon Signed Ranks Test

Knee Expectations Items

 

P-value

Relief of pain

Higher

0.127

Improve ability to walk short distance (indoors, 1 block)

Higher

0.036

Improve ability to walk medium distance (take a walk, < 1 mile)

Higher

0.097

Improve ability to walk

long distance (> 1 mile)

Higher

0.254

Remove the need for a cane, crutch or walker

Higher

0.012

Make knee or leg straight

Higher

0.015

Improve ability to go up stairs

Higher

0.007

Improve ability to go down stairs

Higher

0.012

Improve ability to kneel

Higher

0.503

Improve ability to squat

Higher

0.083

Improve ability to use public transportation, drive

Higher

0.006

Be employed for monetary reimbursement

Higher

0.489

Improve ability to participate in recreation (e.g. dancing, pleasure travel)

Higher

0.071

Improve ability to perform daily activities (e.g., household chores, daily routine)

Higher

<0.0026

Improve ability to exercise or participate in sports

Higher

0.015

Improve ability to change position (e.g. go from sitting to standing or from standing to sitting)

Higher

0.003

Improve ability to interact with others (for example, take care of someone, play with children)

Higher

<0.0026

Improve sexual activity

Higher

0.036

Improve psychological well-being

Higher

0.003

  Bonferroni corrected significant P-value <0.0026

Table 2: Pre-Operative Data

Variable

RA Cases

N=62

OA Controls

N=124

P-value

Expectations score

73.7±18.5

79.8±17.1

0.030

WOMAC Pain

10.8±2.8

9.8±3.3

0.040

WOMAC Stiffness

5.1±1.5

4.7±1.6

0.188

WOMAC Function

38.6±11.2

34.7±11.9

0.048

SF-36 PCS

29.3±7.7

32.5±7.8

0.009

SF-36 MCS

45.4±13.1

48.2±13.1

0.190

EQ5D scale

62.9±21.6

71.1±20.4

0.017

EQ5D score

0.6±0.2

0.6±0.2

0.279


Keywords: rheumatoid arthritis (RA)

Disclosure: H. Ghomrawi, None; L. A. Mandl, None; B. Johnson, Johnson & Johnson, 1 ; M. Alexiades, None; S. M. Goodman, None.