Introduction: Patients with systemic lupus erythematosus (SLE) are typically treated with total hip arthroplasty (THA) because of osteonecrosis of the femoral head (ONFH). This study evaluated the outcome of THA in this patient group. Methods: From January 2004 to January 2017, we retrospectively studied 92 THAs for patients with SLE and 92 THAs for age- and sex-matched patients suffering from ONFH due to nonrheumatic etiologies Both groups were treated with cementless THA and followed up for an average of 50.9 ± 30.6 months. Their surgical outcomes and complications were evaluated and compared. Results: No significant difference existed in age, sex, weight, height, follow-up time, and Ficat staging between the groups. All patients with SLE were in inactive or stably active disease conditions. For all patients, the Harris hip score (HHS) (from 52.6 to 92.8; P < 0.001), Physical Component Summary Scale score (PCS) (from 29.4 to 49.3; P < 0.001), and Mmental Component Summary Scale score (MCS) (from 50.5 to 55.5; P < 0.001) of the Short Form-12 improved significantly after surgery. At the final follow-up, the HHS and MCS were comparable between the two groups. The PCS remained lower in the SLE group (P = 0.017), and no recorded revision surgieries in either group. Corticosteroid intake and testing positive for antiphospholipid antibodies, rather than having a SLE disease activity index score greater than zero, were risk factors for higher complications. Discussion: Performing THA for patients with SLE in an inactive or stably active disease condition resulted in comparable postoperative HHS and MCS scores, a lower PCS score, and shorter term postoperative complications compared with patients with ONFH resulting from nonrheumatic diseases. Patients with SLE had a higher risk for postoperative complications. It is generally safe and effective to perform THA in patients with inactive or stably active SLE. However, they still have an increased risk of short-term complications.

Background: Limitations in the lumbar spine movement reduce lumbar vertebral motion and affect spinopelvic kinematics. We studied the influence of lumbar intervertebral disc degeneration on spinofemoral movement, from standing to sitting, in patients undergoing total hip arthroplasty (THA). Methods: Of 138 consecutive patients scheduled for THA due to unilateral avascular necrosis (AVN) of the femoral head, those with ≥3 discs with University of California at Los Angeles (UCLA) disc degeneration score > 1 were defined as the lumbar degenerative disc disease (LDD) group, and the remaining patients constituted d the control group. Full body anteroposterior and lateral EOS images in the standing and sitting positions were obtained. Pelvic incidence (PI), L1 slope (L1 s), lumbar lordosis angle (LL), pelvic tilt (PT), sacral slope (SS), femoral slope (Fs), sagittal vertical axis (SVA), hip flexion, lumbar spine flexion, and total spinofemoral flexion were measured on the images and compared between groups. Results: No significant between-group differences were observed in the height, weight, body mass index, AVN staging, or PI, SS, and Fs on standing. The LDD group included more females and older patients, had 5°lesser LL, 5°g reater PT, and larger SVA. From standing to sitting, the PI remained constant in both groups. Total spinofemoral flexion was 7°less, lumbar spine flexion 16°less, L1 slope change 6°less, and SS change 8°less, and hip flexion was 7°more in the LDD than in the control group. The spine/hip flexion ratio was significantly lower in the LDD group (0.3 versus 0.7; p < 0.001). On regression analysis, the LDD group (p < 0.001) and older age (p = 0.048) but not sex, weight, or height were significant univariate predictors of decreased spine/hip ratio. Conclusions: Patients with LDD leant more forward and had a larger pelvis posterior tilt angle on standing and a decreased lumbar spine/hip flexion ratio, with more hip joint flexion, on sitting, to compensate for reduced lumbar spine flexion. Surgeons should be aware that elderly patients with multiple LDD have significantly different spinofemoral movements and increased risk of posterior dislocation post-THA. Preoperative patient identification, intraoperative surgical technique modification, and individualized rehabilitation protocols are necessary.