Risk factors for subchondral insufficiency fracture of the femoral head in renal transplant patients.

INTRODUCTION: Risk factors associated with subchondral insufficiency fracture (SIF) of the femoral head have not been established. The aim of the present study was to determine the incidence and risk factors for SIF of the femoral head following renal transplantation (RT). MATERIALS AND METHODS: We analyzed the cases of 681 RT patients (mean age at surgery: 49.5 ± 13.6 years, 249 women, 432 men) to determine the incidence of SIF. Hip magnetic resonance imaging (MRI) was performed 6 months post-RT. The following potential predictors of SIF were evaluated: (1) patient's condition at RT: bone mineral density (BMD), pre-RT laboratory values including calcium (Ca), phosphorus (P), calcium-phosphorus product (Ca × P), and intact parathyroid hormone; the patient and donor's blood relationship; and mismatching number of human leukocyte antigens (HLAs), and (2) post-RT dosage(s) of steroid(s), the immunosuppressive regimen, and the incidence of acute rejection. RESULTS: SIF was observed in 15 hips (13 patients, 1.9%). We successfully matched 39 patients without SIF. A multivariate logistic regression analysis adjusted for cumulative dosages of steroids, revealed the following were risk factors for SIF: osteoporosis (OR: 11.4, p = 0.046), lumbar BMD (OR: 0.003, p = 0.038), pre-RT serum P (OR 2.68, p = 0.004), and pre-RT serum Ca × P (OR: 1.11, p = 0.005). CONCLUSION: Since osteoporosis, the lumbar BMD, serum P, and serum Ca × P were identified as risk factors for a post-RT SIF, these factors should be evaluated before RT for the prediction of the SIF risk.

Impact of pelvic incidence on lumbar osteophyte formation and disc degeneration in middle-aged and elderly people in a prospective cross-sectional cohort.

PURPOSE: Pelvic incidence (PI) is unique to each individual and does not change throughout life. High PI is related to lumbar spondylolisthesis, but associations of PI with lumbar osteophyte formation and disc degeneration are unclear. The objective was to evaluate relationships of PI with lumbar osteophyte formation and disc degeneration, as well as spinal sagittal alignment and geriatric diseases, in middle-aged and elderly people. METHODS: A total of 1002 volunteers (male: 434, female: 568, average age: 63.5) were prospectively examined for lumbar osteophyte formation (Nathan class ≥ 2) and disc degeneration (disc score ≥ 3). High (PI > 51, n = 501) and low (PI ≤ 51, n = 501) PI groups were defined. Clinical factors, frailty, sarcopenia, and physical quality of life (QOL) were compared between these groups, and risk factors for lumbar osteophyte formation and disc degeneration were identified in multivariate logistic regression analysis. RESULTS: Physical QOL was poorer in people with lumbar osteophyte formation (54.8%) and disc degeneration (33.6%). Age, male gender, spinal parameters including PI, bone mineral density, back muscle strength, and gait ability differed significantly between the groups, whereas frailty and sarcopenia were not significantly different. Low PI, low lumbar lordosis, elder age, male gender, high BMI, and weak back muscle strength were significant risk factors for lumbar osteophyte formation and disc degeneration. CONCLUSIONS: Low PI was identified as a risk factor for lumbar osteophyte formation and disc degeneration, both of which reduce physical QOL in middle-aged and elderly people. These slides can be retrieved under Electronic Supplementary Material.

Risk Factors for Proximal Junctional Fracture Following Fusion Surgery for Osteoporotic Vertebral Collapse with Delayed Neurological Deficits: A Retrospective Cohort Study of 403 Patients.

INTRODUCTION: Approximately 3% of osteoporotic vertebral fractures develop osteoporotic vertebral collapse (OVC) with neurological deficits, and such patients are recommended to be treated surgically. However, a proximal junctional fracture (PJFr) following surgery for OVC can be a serious concern. Therefore, the aim of this study is to identify the incidence and risk factors of PJFr following fusion surgery for OVC. METHODS: This study retrospectively analyzed registry data collected from facilities belonging to the Japan Association of Spine Surgeons with Ambition (JASA) in 2016. We retrospectively analyzed 403 patients who suffered neurological deficits due to OVC below T10 and underwent corrective surgery; only those followed up for　≥2 years were included. Potential risk factors related to the PJFr and their cut-off values were calculated using multivariate logistic regression analysis and receiver operating characteristic (ROC) analysis. RESULTS: Sixty-three patients (15.6%) suffered PJFr during the follow-up (mean 45.7 months). In multivariate analysis, the grade of osteoporosis (grade 2, 3: adjusted odds ratio (aOR) 2.92; p=0.001) and lower instrumented vertebra (LIV) level (sacrum: aOR 6.75; p=0.003) were independent factors. ROC analysis demonstrated that lumbar bone mineral density (BMD) was a predictive factor (area under curve: 0.72, p=0.035) with optimal cut-off value of 0.61 g/cm2 (sensitivity, 76.5%; specificity, 58.3%), but that of the hip was not (p=0.228). CONCLUSIONS: PJFr was found in 16% cases within 4 years after surgery; independent risk factors were severe osteoporosis and extended fusion to the sacrum. The lumbar BMD with cut-off value 0.61 g/cm2 may potentially predict PJFr. Our findings can help surgeons select perioperative adjuvant therapy, as well as a surgical strategy to prevent PJFr following surgery.