Background/Purpose: Due to the progressive and debilitating nature of knee arthritis, total knee arthroplasty (TKA) is the ultimate outcome. TKA is an effective surgical intervention for relieving pain and restoring function in patients with end-stage knee arthritis. Even though the beneficial impact of TKA is well documented, its effect on patient reported indices of pain and health related quality of life (HRQoL), especially in the RA population, are scarce. We examined the effects of TKA on pain and HRQoL in RA and OA patients.
Methods: Rheumatologist-diagnosed RA (n=834) and OA (n=315) patients undergoing primary TKA during 1999-2012 were identified. Measures of pain, function and HRQoL were obtained in three consecutive 6-month intervals: pre-operative (baseline), peri-operative and post-operative (recovery). Descriptive statistics and one-way ANOVA were used to compare TKA outcomes by diagnosis. Effect sizes were calculated between baseline and recovery period for each measure and graphs were plotted to follow these over time (±3 years of TKA), for both RA and OA patients.
Results: Patients with RA and OA were similar in age (65 vs. 68 years, respectively) and elapsed time [baseline sampling to TKA and TKA to recovery] (4.4 vs. 4.5 and 10.4 vs. 10.3 months). Post TKA, significant improvements were observed for most domains of pain, function and HRQoL indices within both disease groups (p<0.001). The beneficial effects of TKA were more profound in OA patients, as compared to RA, for all measures of pain and HRQoL indices except for RADAI/total joint count [RA (-0.42) vs. OA (-0.30)] and EQ-5D [RA (0.07) vs. OA (0.06)]. By effect size, maximum significant (p <0.001) improvement was shown in index knee pain (RA -1.69 vs. OA -1.85). Beyond pain outcomes, EQ-5D and SF-36 PCS were the most responsive HRQoL measures in detecting post-TKA improvement in RA and OA (p<0.001 in both groups), respectively (Table 1). For all outcomes examined, improvements were greatest in the first post-operative year, showing gradual declines thereafter.
Conclusion: TKA is highly effective in reducing clinically relevant index knee pain to a greater extent than other subjective HRQoL indices in patients with RA, although this improvement is less marked than that observed in OA patients. Gains observed in pain, function, and HRQoL are most striking in the first 12 months following TKA, paralleling levels reported often years prior to joint replacement. From our results, TKA acts as a “time machine” by which a patient returns to a reduced pain and less disabled lifestyle, before the arthritic process catches up, which is strikingly faster in RA.
Table 1. Mean change (SD) and effect size between baseline and recovery period
|
RA |
Effect size |
OA |
Effect size |
|
|
Index knee pain (0- 3)# |
-1.47 (0.88) |
-1.69 |
-1.47 (0.79) |
-1.85 |
|
VAS Pain (0 – 10)# |
-1.12 (2.67) |
-0.42 |
-1.74 (2.60) |
-0.67 |
|
RADAI-Total joint count (0 – 16)@ |
-0.40 (4.92) |
0.08 |
-0.31 (4.61) |
-0.07 |
|
RADAI-Total joint score (0 – 48)@ |
-1.41 (10.07) |
-0.14 |
-1.88 (8.47) |
-0.22 |
|
HAQ@ |
-0.09 (0.66) |
-0.14 |
-0.15 (0.59) |
-0.25 |
|
HAQ II |
-0.18 (0.64) |
-0.29 |
-0.19 (0.58) |
-0.32 |
|
SF-36 PCS (0 -100) |
3.59 (9.80) |
0.37 |
4.57 (9.89) |
0.46 |
|
EQ-5D (US) (0-1) |
0.07 (0.20) |
0.40 |
0.06 (0.20) |
0.32 |
# and @ represent indices with significantly (p<0.05) less and more severe scores, respectively, in RA (vs. OA) patients undergoing TKA at baseline. Bold numbers represent significant (p <0.05) values between baseline and recovery within the respective groups
Disclosure:
A. Dusad,
None;
S. Pedro,
None;
K. Garvin,
None;
C. Hartman,
None;
J. O’Dell,
Abbvie, Lilly, Antares, Medac,
5;
T. R. Mikuls,
None;
K. Michaud,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/patient-reported-outcomes-following-total-knee-arthroplasty-in-rheumatoid-arthritis-and-osteoarthritis/