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