Background Rheumatoid arthritis (RA) patients have worse reported outcomes after total knee replacement (TKR) as compared with osteoarthritis (OA) patients. It is unknown if this persists in a contemporary cohort of RA patients with high DMARD and biologic use.
Objectives To compare baseline and 2 year outcomes of primary and revision TKR (RTKR) in patients with RA versus OA.
Methods All TKR and RTKR enrolled in a single institution registry between 5/1/2007 and 7/1/2010 with pre-operative data and who were alive at two years were eligible for this analysis. Patients with two eligible procedures only contributed data from the second. RA cases were identified by self report or ICD-9 code and validated by chart review. Patients with ICD-9 codes for other systemic rheumatic disease or fractures were excluded. Satisfaction at 2 years was measured on a 5-point Likert scale. Differences between groups were compared using unpaired Student’s t test, Chi-Square or Fisher’s exact test as appropriate.
Results 5,384 primary TKR and 374 RTKR were eligible for this study with 178 RA TKR and 32 RA RTKR. 94% had 2-year follow-up. (Table 1) More TKR RA cases were female with lower BMI and more comorbidities. 81% of RA TKR were on DMARD therapy, 44% on biologics; RTKR 87% and 50% respectively. RA TKR had significantly worse pain and function pre-operatively but no difference at 2 years. RA and OA had similar clinically meaningful improvements in pain and function, (WOMAC change >10) and similar numbers of patients with poor 2-year outcomes (WOMAC pain or function≤ 60). Satisfaction was high for both groups. For RTKR, OA and RA patients had similar pain and function pre-operatively, but RA had significantly less pain and better function at 2 years. OA RTKR were much less satisfied at 2 years.
Conclusions Although contemporary RA patients undergoing TKR have worse pre-operative pain and function compared with OA patients, they have comparable 2 year outcomes. By contrast, RTKR RA patients have less pain and better function at 2 years than OA RTKR- differences which were clinically meaningful. These data demonstrate excellent results in contemporary RA TKR and RTKA patients.
Disclosure of Interest None Declared
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