Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: Historically, outcomes for total hip replacement (THR) in ankylosing spondylitis (AS) patients were poor, but contemporary outcomes are not well described. We analyzed two-year THR outcomes in a cohort of AS patients compared with osteoarthritis (OA) controls.
Methods: A case- control study was performed using data from a high volume single institution THR registry. AS were identified by ICD-9 code and confirmed by chart review. AS cases were matched 4:1 by age, bilateral, primary or revision procedure, and date of surgery, and availability of 2 year data, after excluding potential controls with ICD-9 codes for other rheumatic disease or fracture. Self-report quality of life and administrative data were obtained pre-operatively and at 2-years. Pain, function, and quality of life scores were compared between groups using standard statistical methods.
Results: 30 eligible AS THR cases were identified between 5/ 2007 and 10/2010: 21 primary, 2 bilateral, and 7 revisions. Mean age was 52.7 years, (SD 16) ; more AS were male (80% vs 45%; p-value<0.001). AS had worse baseline ASA class (ASA Class≥3: 40% vs 9%; p-value<0.001). 2-year self-report data were available on 63% of AS cases. AS had worse pre-operative WOMAC pain (46.1 vs 54.8; p-value=0.05) and WOMAC function (43.5 vs 53.7; p-value=0.04) compared to OA controls but had similar excellent outcomes at 2 years: WOMAC pain (90.6 vs 92.8; p-value=0.5) and WOMAC function (85.4 vs 90.4; p-value=0.18). AS were as likely as controls to have a clinically meaningful improvement (Δ WOMAC >10) in pain (87% vs 93%; p-value=0.4) and function (100% vs 90%; p-value=0.2) and were no more likely to have a poor outcome (WOMAC < 60) for pain (89% vs 93%; p-value=0.4) or function (89% vs 93%; p-value=0.5). AS without 2-year data had significantly worse pre-op WOMAC function than AS with data (30.9 vs 44.1; p-value=0.04). However, neither AS nor OA without 2-year data had clinically meaningful differences in pre-op pain scores compared with those with data (AS:45 vs 40; p-value=0.31; OA:53.6 vs. 50.5; p-value<0.001). AS SF-12 was lower at baseline (31.3 vs. 36.1; p-value=0.01) and remained clinically significantly worse at 2 years (41.5 vs 50.2; p-value<0.001). Scores on the HSS Expectations Survey were high for both AS and OA (77.5 vs 83.3; p-value=0.24), and both were very/somewhat satisfied with their 2-year outcomes (100% vs 96%; p-value=0.4).
Table 1 |
Total Hip Replacement |
||
|
AS (n=30) |
OA (n=132) |
P-value |
Age (SD) |
52.7 (16.2) |
53.2 (14.6) |
0.88 |
Male, n (%) |
24 (80%) |
59 (45%) |
<0.001 |
WOMAC Baseline Pain (SD) |
46.1 (19.3) |
54.8 (19.3) |
0.05 |
WOMAC 2 year Pain (SD) |
90.6 (14.1) |
92.8 (12.9) |
0.5 |
WOMAC Baseline Function (SD) |
43.5 (22.4) |
53.7 (20.4) |
0.04 |
WOMAC 2 year Function (SD) |
85.4 (17.1) |
90.4 (14.4) |
0.18 |
Δ WOMAC > 10, Pain, n (%) |
13 (87%) |
110 (93%) |
0.36 |
Δ WOMAC > 10, Function, n (%) |
13 (100%) |
96 (90%) |
0.23 |
Poor outcome @ 2 year, WOMAC Pain ≤60, n (%) |
2 (11%) |
7 (6%) |
0.4 |
Poor outcome @ 2 year, WOMAC Function ≤60, n (%) |
2 (11%) |
8 (7%) |
0.52 |
SF-12 PCS Baseline (SD) |
31.3 (8.4) |
36.1 (8.1) |
0.015 |
SF-12 PCS 2 year (SD) |
41.5 (11.0) |
50.2 (9.8) |
<0.001 |
Expectation Score (SD) |
77.5 (17.7) |
83.3 (18.1) |
0.24 |
Baseline ASA class, n (%) |
|
|
<0.001 |
Class 1 or 2 |
18 (60%) |
119 (91%) |
|
Class 3 |
12 (40%) |
12 (9%) |
|
Satisfaction at 2 years, Overall, n (%) |
|
|
|
Very Satisfied |
14 (78%) |
102 (86%) |
0.42 |
Somewhat Satisfied |
4 (22%) |
12 (10%) |
|
Neither Satisfied nor Dissatisfied |
0 (0%) |
2 (2%) |
|
Somewhat Dissatisfied |
0 (0%) |
0 (0%) |
|
Very Dissatisfied |
0 (0%) |
3 (3%) |
|
Conclusion: AS patients achieve similar levels of pain relief at 2-years compared with OA controls. These data may overestimate 2-year function in AS, but the majority have significant improvement. Despite having worse pre-operative health status than matched OA controls, THR is an effective treatment for end stage hip arthritis in AS. However, lower 2-year SF-12 PCS scores suggest that some limitations due to health status persist. These data can be used to ensure AS patients have accurate expectations of THR.
Disclosure:
S. M. Goodman,
None;
R. Zhu,
None;
W. T. Huang,
None;
M. P. Figgie,
Mekanika,
1,
Ethicon,
2;
M. Alexiades,
None;
L. A. Mandl,
Boehringer Ingelheim,
2.
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