Three-point Method to Guide the Tibial Resection and Component Placing in Total Knee Arthroplasty.

OBJECTIVE: To introduce a three-point method combining the midpoint of the posterior cruciate ligament (PCL), the midsulcus of the tibial spines, and the midpoint of the anterior cruciate ligament (ACL) to determine appropriate tibial resection and component placing during TKA and to compare this method with Insall's 1/3 method. METHODS: A consecutive series of 128 knees that underwent TKA from January 2015 to August 2018 were analyzed. In one group (64 knees), the medial 1/3 of tibial tubercle (the Insall's traditional method) was used for tibial component alignment. In the other group (64 knees), the three-point line connecting the midpoint of the PCL, the midpoint of the tibial spines, and the midpoint of the ACL was used for tibial component alignment. Both groups used the anterior tibial tendon as the distal reference for tibial resection. The coronal alignment error of the tibial component was determined by the angle between the line parallel to the tibial component platform and the tibial mechanical axis measured on postoperative radiograph. The axial rotation error of the femoral or tibial component was the intersection angle between the transepicondylar axis (TEA) and a line tangent to the posterior edge of the femoral or tibial component measured on CT. The coronal and axial alignment errors were compared between the two groups. RESULTS: The average coronal alignment error of the tibial component in the three-point method group was 0.2° ± 1.4° versus - 0.9° ± 1.8°in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in the three-point method group reduced by 37.3% compared to Insall's traditional method group. The average axial rotation error of the femoral component was 0.2° ± 1.2° in the three-point method group versus - 1.1° ± 1.7° in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in three-point method group decreased by 43.9% compared to Insall's traditional method group. The average axial rotation error of the tibial component was 0.4° ± 1.4° versus - 1.4° ± 1.8° in the Insall's 1/3 method group (P < 0.001), and the mean absolute value in the three-point method group reduced by 35.5% compared to the Insall's traditional method group. The rates of rotation outliers were significantly lower in the three-point method group (P < 0.05). CONCLUSION: The line connecting the midpoint of the PCL, the midsulcus of the tibial spines, and the midpoint of the ACL could be used as the reference for the tibial resection and component placing. This method appears to be more accurate than Insall's 1/3 method. The results of this study provide a candidate method for component orientation with little error.

Dimensional Changes of Lumbar Intervertebral Foramen in Direct Anterior Approach-Specific Hyperextension Supine Position.

OBJECTIVE: To investigate the changes in the lumbar intervertebral foramen (LIVF) dimensions from neutral supine to direct anterior approach (DAA)-specific hyperextension supine position through a standardized three-dimensional (3D) reconstruction computerized tomography (CT) method. METHODS: A total of 35 healthy volunteers (18 men and 17 women) were included in this retrospective study. The mean age of enrolled subjects was 28.9 ± 5.0 years. In September 2018, all the individuals underwent a 3D CT scan of the lumbar spine in neutral and 30° hyperextension supine positions, which mimicked the patient's position in DAA total hip arthroplasty (THA). The dimensions of the LIVF, including foraminal area, height, and width, were measured on 3D reconstructed CT models at all lumbar foraminal levels. Foraminal area was defined as the area bounded by the adjacent superior and inferior vertebral pedicles, the posterosuperior boundary of the inferior vertebral body, the surface of the intervertebral disc posteriorly, the posteroinferior boundary of the superior vertebral body, and the surface of the ligamentum flavum anteriorly. Foraminal height was defined as the longest distance between the border of the superior and the inferior pedicle. Foraminal width was defined as the shortest distance between the posteroinferior edge of the superior vertebrae and the opposing boundary. Subgroup analysis and multiple linear regression were used to evaluate the relationship between percentage changes of the LIVF dimensions and side, sex, and age. RESULTS: The LIVF dimensions varied significantly between the two positions at all levels (P < 0.05). From neutral to hyperextension supine position, the foraminal area reduced by 20.1% at lumbar 1-2 (L1-2 ), 22.6% at L2-3 , 19.9% at L3-4 , 18.1% at L4-5 , and 12.0% at lumbar 5-sacral 1 (L5 -S1 ) level, respectively; the foraminal height reduced by 9.5% at L1-2 , 10.5% at L2-3 , 9.5% at L3-4 , 9.6% at L4-5 , and 6.1% at L5 -S1 level, respectively; the foraminal width reduced by 12.8% at L1-2 , 14.5% at L2-3 , 13.0% at L3-4 , 10.4% at L4-5 , and 8.4% at L5 -S1 level, respectively. The changes in LIVF dimensions were biggest at L2-3 level and smallest at L5 -S1 level. Subgroup analysis showed that there were no significant differences in the percentage changes of LIVF dimensions between the sexes and sides (P > 0.05). Multiple linear analysis showed that the percentage changes of LIVF dimensions were not related to side, sex, and age (P > 0.05). CONCLUSION: The dimensions of the LIVF showed significant decrease at all levels in the DAA-specific hyperextension supine position compared with the neutral supine position, and the percentage changes of LIVF dimensions were not influenced by side, sex, and age.

Elevated Serum and Cerebrospinal Fluid Free Fatty Acid Levels Are Associated with Unfavorable Functional Outcome in Subjects with Acute Ischemic Stroke.

The aim of this study was to evaluate the prognostic value of serum and cerebrospinal fluid (CSF) free fatty acid (FFA) levels in a cohort of patients with an acute ischemic stroke (AIS). In a prospective study, FFA levels were measured using an enzyme cycling method on admission in serum and CSF of 252 consecutive patients with AIS. The prognostic value of FFA to predict the functional outcome and mortality within 90-day was compared with the National Institutes of Health Stroke Scale score and with other known outcome predictors. Serum and CSF levels of FFA increased with increasing severity of stroke as defined by the NIHSS score (all P < 0.001). Patients with an unfavorable outcomes and non-survivors had significantly increased FFA serum and CSF levels on admission (all P < 0.0001). Multivariate logistic regression analysis adjusted for common risk factors showed that serum FFA ≥0.71 mmol/L (third quarters) was an independent predictor of functional outcome (odds ratios (OR) = 4.86; 95 % confidence interval (CI) 2.26-10.48) and mortality (OR = 7.72; 95 % CI 3.01-21.48). The area under the receiver operating characteristic curve of serum FFA was 0.79 (95 % CI, 0.72-0.86) for functional outcome and 0.86 (95 % CI, 0.78-0.94) for mortality. Similarly, CSF FFA level also was an indicator for predicting of functional outcome and mortality. FFA levels in serum and CSF may serve as independent biomarkers in addition of the traditional methods for assessing the functional outcome and mortality of AIS.

The diagnostic and prognostic value of serum CXCL12 levels in patients with ischemic stroke.

The aim of this study was to investigate the potential diagnostic and prognostic role of CXC chemokine ligand-12 (CXCL12) in Chinese patients with acute ischemic stroke (AIS). All consecutive patients with first-ever AIS from January 2014 to August 2014 were recruited to participate in the study. CXCL12 and NIH Stroke Scale were measured at the time of admission. Short-term functional outcome was measured by modified Rankin scale 3 months after admission. Multivariate analyses were performed using logistic regression models. Receiver operating characteristic (ROC) curve was used to evaluate the accuracy of serum CXCL12 in diagnosing stroke and prognosing functional outcome. From 375 screened patients, a total of 288 patients with first-ever AIS were included in this study. Based on the ROC curve, the optimal cutoff value of serum CXCL12 levels as an indicator for auxiliary diagnosis of AIS was projected to be 3.5 ng/mL, which yielded a sensitivity of 88.1 % and a specificity of 73.5 %, with the area under the curve at 0.907 (95 % CI 0.882-0.932). In multivariate analysis, there was an increased risk of unfavorable outcome associated with serum CXCL12 levels ≥7.6 ng/mL (OR 4.356, 95 % CI 2.993-7.132, P < 0.0001) after adjusting for possible confounders. Our study demonstrated that elevated serum CXCL12 level at admission was an independent diagnostic and prognostic marker in patients with AIS.