Symptomatic knee osteonecrosis in patients with systemic lupus erythematosus: a case–control study

Anti-RNP Antibody: A Potential Novel Predictor for Osteonecrosis in Systemic Lupus Erythematosus

Objective

To explore risk factors for developing osteonecrosis in patients with systemic lupus erythematosus (SLE).

Methods

Twenty-six SLE patients with osteonecrosis from January 2018 to December 2019 were described. Fifty SLE patients without osteonecrosis were selected as controls from the SLE database (total 2,680) of our hospital during the same period. Clinical manifestations and laboratory tests were recorded and analyzed, especially antibodies. Univariate and multivariate analyses were used to evaluate possible associated risk factors.

Results

Twenty-six (3 male, 23 female) SLE patients with osteonecrosis were confirmed by X-ray and magnetic resonance imaging. The median course from SLE onset to osteonecrosis onset was 45 (range 2–302) months. Seven (27%) patients had a single joint involved and 19 (73%) patients had two or more joints involved. Besides, the incidence of femoral head osteonecrosis (FHON), knee ON, and humerus head ON were 85% (22/26), 27% (7/26), and 12%(3/26), respectively. The multivariate logistic regression analysis showed that the score of European Consensus Lupus Activity Measurement (ECLAM) at SLE onset [odds ratio (OR) 1.37; 95% confidence interval (CI) 1.07–1.75], a cumulative dose of prednisone above 10 g (OR 15.49; 95% CI 3.38–84.61), and positive of independent anti-RNP antibodies (OR 3.35; 95% CI 0.80–10.73) were significantly associated with osteonecrosis in SLE.

Conclusion

The score of ECLAM at SLE onset, a cumulative dose of prednisone above 10 g, and positive anti-RNP antibodies are associated with osteonecrosis in SLE. Herein, we reported for the first time that anti-RNP antibodies were associated with osteonecrosis in SLE patients and might be a novel predictor.

Long-lasting severe knee pain in a SLE patient after renal transplantation: what is the reason? A case report and literature review

Musculo-skeletal complaints in a patient suffering from systemic lupus, with co-existing chronic renal failure, undergoing immunosuppressive treatment after kidney transplantation, can have a varied etiology. The aim of this work was to present a case based review of differential diagnosis of knee pain in such a patient. A literature search was carried out using MEDLINE/PubMed, Google Scholar and EBSCO, with no time limit. We undertook a systematic review of the literature published in English, limited to full-text publications of original articles, letters to the editor, and case reports in peer-reviewed journals, for a discussion and analysis of studies reporting arthralgia in patients with lupus after kidney transplantation. We present a case report of a 45-year-old woman with lupus nephritis, after kidney transplantation, who started to complain of increasing pain in the knees, most pronounced at night and after physical activity approximately 2 years after transplantation. Extensive causal diagnostics were carried out, which revealed bilateral extensive regions of bone infarction in the femur and tibia, chondropathy, degenerative changes of medial meniscuses in the body and posterior horn as well as chondromalacia of the patella. Establishing the right diagnosis is crucial for implementing appropriate treatment.

Risk of osteonecrosis in systemic lupus erythematosus: An 11-year Chinese single-center cohort study

OBJECTIVE

Osteonecrosis (ON), which can lead to physical disability, is a common complication of systemic lupus erythematosus (SLE). The purpose of this study was to determine the prevalence of ON and identify possible risk factors in Chinese SLE patients.

METHODS

SLE patients who fulfilled the 1997 American College of Rheumatology SLE classification criteria were recruited from the Peking Union Medical College Hospital. The chi-square test (χ² test) and multivariate regression analyses were used to evaluate risk factors. The Cox proportional-hazards model was used to construct the survival curves and estimate the simultaneous effects of prognostic factors on survival.

RESULTS

We consecutively enrolled 1,158 patients, of which 88 patients (7.6%) developed ON. Among ON patients, 57.1% of patients had isolated femoral head necrosis and 42.9% had multiple joint involvement. The mean age of ON patients (24.62 ± 8.89 years) was significantly younger than SLE patients without ON (27.23 ± 10.16 years, p = 0.09). The ON group presented with a much longer disease course (10.68 ± 5.97 years, p < 0.001) and increased incidence of arthritis, kidney, and central nervous system (CNS) involvement (65.9% [p < 0.05], 57.6% [p < 0.05], and 16.5% [p < 0.05], respectively, in the ON group). ON patients were more likely to be treated with glucocorticoid (GC) and to receive a high dose of prednisolone at the initial stage of SLE (p < 0.05). The percentage of patients who received hydroxychloroquine was much higher in the control group (p < 0.001). Cox regression analysis suggested that CNS involvement and GC therapy were two independent risk factors for ON in SLE patients. The presence of anti-phospholipid antibodies (aPLs) was a risk factor for multiple joint necrosis (odds ratio: 6.28, p = 0.009).

CONCLUSIONS

ON remains a serious and irreversible complication in SLE. In addition to glucocorticoid therapy, we found that CNS system involvement was a risk factor for ON, while the administration of hydroxychloroquine was a protective factor. The clinical characteristics of multiple site ON patients were distinct from isolated femoral head necrosis patients. The presence of aPLs was a risk factor for multiple site osteonecrosis.

Effects of hypoxia environment on osteonecrosis of the femoral head in Sprague-Dawley rats

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) is a disease in which the blood supply of the femoral head is interrupted or damaged, resulting in joint dysfunction. Hypoxic environments increase the expression of EPO, VEGF, and HIF causes vascular proliferation and increases the blood supply. It also causes the organism to be in a state of hypercoagulability and increases thrombosis. Therefore, the purpose of this study was to explore the occurrence of ONFH after the use of glucocorticoids (GCs) under conditions of hypoxia tolerance for a long time.

MATERIALS AND METHODS

Sprague-Dawley rats were fed in a hypobaric hypoxic chamber at an altitude of 4000 m, the whole blood viscosity, and plasma viscosity were determined to analyze the blood flow and hemagglutination. Western blotting, polymerase chain reaction, and immunohistochemistry were used to detect EPO, VEGF, CD31, and osteogenesis related proteins. Femoral head angiography was used to examine the local blood supply and micro-CT scanning was used to detect the structure of the bone trabecula.

RESULTS

Under hypoxic environments, the expression of EPO and VEGF increased, which increased the local blood supply of the femoral head, but due to more severe thrombosis, the local blood supply of the femoral head decreased.

CONCLUSIONS

Hypoxic environments can aggravate ONFH in SD rats; this aggravation may be related to the hypercoagulable state of the blood. We suggest that long-term hypoxia should be regarded as one of the risk factors of ONFH and we need to conduct a more extensive epidemiological investigation on the occurrence of ONFH in hypoxic populations.

Systemic lupus erythematosus patients with high disease activity are associated with accelerated incidence of osteonecrosis: a systematic review and meta-analysis

Osteonecrosis (ON) is one of the serious complications for systemic lupus erythematosus (SLE); we aimed to study the risk relationship between disease activity and incidence of ON in SLE patients. The PubMed, Embase, and Cochrane library databases were searched for papers published up to May 2016 with English-language restriction; studies that compared disease activity between SLE patients with and without ON would be included, and eight studies involving a total of 1119 SLE patients were included. The incidence of ON in SLE was significantly associated with high patient's disease activity, including the degree (pool odds ratio 2.54, 95% confidence interval [CI] [1.33, 4.86], p = 0.005) and the scores (mean difference 2.33, 95% CI [0.86, 3.80], p = 0.002). Besides, immunosuppressive drug use was also a significant risk factor for ON (p = 0.00001), while antimalarial treatment played a protective role (p = 0.01). No evidence of publication bias was detected. In conclusion, disease activity is a significant and independent risk factor for ON, and higher disease activity score is associated with accelerated incidence of ON in SLE patients.