Systemic lupus erythematosus (SLE) is not an independent risk factor for worse short-term outcomes after hip or knee replacement. At 2 years, no difference in pain and function was found between SLE patients and matched controls who underwent hip or knee arthroplasty at a single institution, reported U.H. Shah, MD at New York University Hospital and co-investigators in Lupus.
The results suggest that patients with SLE “have marked improvements in pain and function” after total hip arthroplasty (THA) and total knee arthroplasty (TKA) “and that SLE itself is not associated with worse short-term postoperative pain or function,” the authors wrote.
In older studies, outcomes after joint replacement in SLE patients have been reported to be worse compared with patients with osteoarthritis (OA). Until recently, about half of THA procedures performed in patients with SLE have been for avascular necrosis (AVN), which occurs commonly in patients treated with corticosteroids. However, fewer patients with SLE have been undergoing joint arthroplasty for AVN, the authors note, which is most often attributed to less reliance on corticosteroids in the SLE treatment regimen. Whether or not this change, along with improvements in arthroplasty technique and anesthesia, has led to an improvement in outcomes after joint arthroplasty in patients with SLE was the purpose of the study.
The investigators looked at data from a single-institution arthroplasty registry, comparing outcomes between 99 patients with SLE (or likely SLE, as access to detailed rheumatology records was not possible in all cases) who underwent either THA (n=54) or TKA (n=45) and 198 patients with OA (controls) who underwent these procedures (108 THA, 90 TKA). OA patients were matched to SLE patients on the basis of age, sex, procedure type, and presence of AVN.
Demographic data and self-reported health, function, and quality of life were ascertained from questionnaires completed preoperatively and again at 2 years. Two-year questionnaires were completed by 46% of SLE patients and 52% of OA patients, with no differences in age or body mass index between those who completed and those who did not complete the 2-year questionnaires.
Among those who underwent THA, SLE patients had worse preoperative pain on theWestern Ontario McMaster University Osteoarthritis (WOMAC) scale compared with OA controls (42.5 versus 52.7; P=0.01) but WOMAC function was similar between the groups. Despite worse preoperative pain, at 2 years, WOMAC pain scores were not significantly different between the SLE patients and controls (91.1 versus 92.1, respectively; P=0.77). WOMAC function was also similar at 2 years between the SLE and OA patients (86.4 versus 90.8; P=0.28).
Preoperative scores on the Short Form-36 (SF-36) Physical Component Summary (PCS) were also significantly lower in THA SLE patients versus THA OA controls (25.0 versus 31.7;P=0.0001) and remained significantly lower at 2 years (40.5 versus 48.7; P=0.01) despite the significant improvement in WOMAC scores.
Scores on the Lower Extremity Activity Scale (LEAS) were significantly lower in the THA SLE patients compared with the THA OA controls (8 versus 9; P=0.03) at baseline but improved to 11 by 2 years (indicating an ability to work outside the home at a moderately active job) while the LEAS score improved to 13 (engages in moderately active exercises without difficulty) in the OA group (difference between groups, P=0.02)
Among the patients who underwent TKA, preoperative WOMAC pain and function scores were similar between the SLE and OA patients. At 2 years, there was improvement in these domains in both groups, so that the 2-year scores were not significantly different between the groups: WOMAC pain score was 85.7 in the SLE patients and 88.6 in the OA controls (P =0.50), and the WOMAC function score was 83.7 and 85.1, respectively (P=0.77).
The SF-36 PCS score was significantly lower preoperatively in the TKA SLE patients than in the TKA OA controls, and remained lower despite improvement at 2 years (final scores: 40.2 versus 47.2, respectively; P=0.02).
There was no significant difference between TKA groups in preoperative or 2-year SF-36 Mental Component Summary score, Euro-Qol 5D score, and LEAS score.
Although there were significant differences preoperatively between the SLE THA and TKA patients, “outcomes between the groups were similarly excellent,” the authors concluded. “This is important information to consider when counseling SLE patients contemplating arthroplasty.”
They list specific limitations, including the lack of patient interview or examination to confirm SLE, a low response to the 2-year questionnaires (with the potential for patients with poor outcomes and chronic diseases being less likely to respond), the lack of specific SLE measures of disease activity, the lack of SLE serologies, the performance of surgeries only at a high-volume orthopedic hospital (meaning that results may not be generalizable) and potential confounders other than age, sex, procedure, and presence of AVN.
The study was supported by a grant from the Agency for Healthcare Research and Quality Centers for Education and Research on Therapeutics and by the Weill Cornell Clinical Translational Science Center.
The authors report no conflicts of interest.
- Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner
LAST UPDATED 02.03.2015