Comparison of patellar tracking according to different angles of external rotation of femoral component in varus knee of Asians.

PURPOSE: Racial difference in the femoral geometry may exist. Asian femurs may be more externally rotated. If anatomical differences in distal femur had existed between Caucasians and Asians, the group with 5° external rotation of the femoral component should have shown better results than the group with 3° external rotation of the femoral component have. METHODS: 598 patients underwent total knee arthroplasty in our institution, among whom 83 patients (115 knees) who had postoperative computed tomography (CT) were studied retrospectively. Sixty-two knees were set in 5° of external rotation of femoral component relative to the posterior condylar axis (group A) while the others (53 knees) were set in 3° (group B). The femoral component rotation (FCR) was measured and compared using CT. The patellar tilting (PT) and the lateral patellar displacement (LPD) were measured to evaluate the patellar tracking using Merchant view. And postoperative clinical scores were compared. RESULTS: The mean FCRs showed no significant difference between two groups ( p > 0.05). The mean PT and LPD showed no statistically significant difference either ( p > 0.05). There were no statistical differences in clinical scores. CONCLUSION: The difference in the patellar tracking between the two groups could not be demonstrated. There were no statistical differences in clinical scores either. We concluded there is no need to adhere to 5° external rotation.

Glenoid version and size: does gender, ethnicity, or body size play a role?

INTRODUCTION: Variations in glenoid morphology among patients of different gender, body habitus, and ethnicity have been of interest for surgeons. Understanding these anatomical variations is a critical step in restoring normal glenohumeral structure during shoulder reconstruction surgery. METHODS: Retrospective review of 108 patient shoulder CT scans was performed and glenoid version, AP diameter and height were measured. Statistical multiple regression models were used to investigate the ability of gender and ethnicity to predict glenoid AP diameter, height, and version independently of patient weight and height. RESULTS: The mean glenoid AP diameter was 24.7 ± 3.5, the mean glenoid height was 31.7 ± 3.7, and the mean glenoid version was 0.05 ± 9.05. According to our regression models, males would be expected to exhibit 8.4° more glenoid retroversion than females (p = 0.003) and have 2.9 mm larger glenoid height compared to females (p = 0.002). The predicted male glenoid AP diameter was 3.4 mm higher than that in females (p < 0.001). Hispanics demonstrated 6.4° more glenoid anteversion compared to African-Americans (p = 0.04). Asians exhibited 4.1 mm smaller glenoid AP diameters than African-Americans (p = 0.002). An increase of 25 kg in patient weight resulted in 1 mm increase in AP diameter (p = 0.01). CONCLUSIONS: Gender is the strongest independent predictor of glenoid size and version. Males exhibited a larger size and more retroverted glenoid. Patient height was found to be predictive of glenoid size only in patients of the same gender. Although variations in glenoid size and version are observed among ethnicities, larger sample size ethnic groups will be necessary to explore the precise relations. Surgeons should consider gender and ethnic variations in the pre-operative planning and surgical restoration of the native glenohumeral relationship. LEVEL OF EVIDENCE: Anatomic Study.

The cohort study for the determination of reference values for spinopelvic parameters (T1 pelvic angle and global tilt) in elderly volunteers.

PURPOSE: T1 pelvic angle (TPA) and global tilt (GT) are spinopelvic parameters that account for trunk anteversion and pelvic retroversion. To investigate spinopelvic parameters, especially TPA and GT, in Japanese adults and determine norms for each parameter related to health-related quality of life (HRQOL). MATERIALS AND METHODS: Six hundred and fifty-six volunteers (262 men and 394 women) aged 50-92 years (mean, 72.8 years) were enrolled in this study. The incidence of vertebral fracture, spondylolisthesis and coronal malalignment were measured. Five spinopelvic parameters (TPA, GT, sagittal vertical axis [SVA], pelvic tilt [PT], and pelvic incidence-lumbar lordosis [PI-LL]) were measured using whole spine standing radiographs. The mean values for each parameter were estimated by sex and decade of life. HRQOL measures, including the Oswestry Disability Index (ODI) and EuroQuol-5D (EQ-5D), were also obtained. Pearson's correlation coefficients were determined between each parameter and HRQOL measure. Moreover, the factors contributing to the QOL score were calculated using logistic regression with age, sex, the existence of vertebral fracture and spondylolisthesis, coronal malalignment (coronal curve >30°) and sagittal malalignment (SVA >95 mm) as explanatory variables and the presence of disability (ODI >40) as a free variable. RESULTS: The mean values for the spinopelvic parameters were as follows: TPA, 17.9°; GT, 23.2°; SVA, 50.2 mm; PT, 18.6°; and PI-LL, 7.5°. TPA and GT strongly correlated with each other (r = 0.990) and with the other spinopelvic parameters. TPA and GT correlated with ODI (r = 0.339, r = 0.348, respectively) and EQ-5D (r = -0.285, r = -0.288, respectively), similar to those for SVA. TPA, GT, PT, and PI-LL were significantly higher in women than in men. PT and PI-LL gradually increased with age, while TPA, GT, and SVA tended to deteriorate after the 7th decade. Based on a logistic regression analysis, the deterioration of ODI was mostly affected by the sagittal malalignment. The TPA and GT cut-off values for severe disability (ODI >40) based on linear regression modeling were 26.0° and 33.7°, respectively. CONCLUSIONS: We determined reference values for spinopelvic parameters in elderly volunteers. Similar to SVA, TPA and GT correlated with HRQOL. TPA, GT, PT, and PI-LL were worse in women and progressed with age.

Gender and racial differences in focal and global acetabular version.

The purpose of this study was to compare the acetabular version between male and female pelvises. We hypothesized that female acetabula would demonstrate more retroversion because Pincer-type femoroacetabular impingement (FAI) is associated with acetabular retroversion, which is more commonly observed in females. 120 bony pelvic specimens were randomly collected. The version was measured at three different axial sections of each acetabulum: cranial, central, and caudal. Males demonstrated significantly less anteversion than females in every section. The global version (the average of all three measurements) was also significantly different between males and females (16° ± 7° and 19° ± 8° respectively, P<0.001). Of the 240 examined acetabuli, 21 demonstrated cranial retroversion (16 males & 5 females). The data showed no significant difference (P=0.353) between global version of African Americans (18° ± 9°) and Caucasians (17° ± 7°). The results of this study suggest that symptomatic FAI in the female population likely reflects a complex interplay of femoral and acetabular dysmorphology and cannot be explained by differences in acetabular version alone.

Femoral version of the general population: does "normal" vary by gender or ethnicity?

OBJECTIVE: The purpose of this study was to compare various gender and ethnic groups to characterize differences in baseline version and rates of retroversion. DESIGN: Retrospective. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Between 2000 and 2009, 417 consecutive patients with femur fractures were treated with an intramedullary nail at level I trauma and tertiary referral center. Of these, 328 with computed tomography scanogram of the normal, uninjured contralateral femur were included in this study. MAIN OUTCOME MEASUREMENTS: Femoral version. RESULTS: The mean alignment for the all patients was 8.84 ± 9.66° of anteversion. There were no statistically significant differences in mean version between African American, white, and Hispanic patients for males or females. Although there were also no significant differences in rates between ethnicities, retroversion was found to be common in white males (21.4%), African American males (15.1%), and all groups of females (>14.3%). Furthermore, nearly 6% of both African American males and females exhibited >10° retroversion. CONCLUSIONS: Although there may not be a significant difference in average femoral version between ethnic and gender groups, retroversion is relatively common, and retroversion >10° was observed in nearly 6% of the African American population. This may have important implications in proper alignment restoration and successful clinical outcomes after intramedullary nailing of femur fractures.

Computed tomography assessment of image-free navigation-assisted cup placement in THA in an Asian population.

The authors hypothesized that an image-free navigation system would be more accurate than postoperative 3-dimensional (3-D) reconstructed computed tomography (CT) for acetabular cup inclination and anteversion during total hip arthroplasty (THA) in an Asian population. Eighty-one THAs were performed in 72 patients using the OrthoPilot image-free navigation system (B. Braun Aesculap, Tuttlingen, Germany). Cup placement position was measured by postoperative 3-D CT and compared with intraoperative navigation data. The discrepancies between the navigation data and the 3-D CT data were analyzed, as well as the correlation factors that affected the discrepancies. The discrepancies between the navigation data and the 3-D CT data were -1.5° ± 7.1° (P=.04) for anteversion and -1.1° ± 7.6° (P=.02) for inclination. The accuracy and precision of the anteversion discrepancies were 5.6° ± 4.4° and 3.2°, respectively. The accuracy and precision of the inclination discrepancies were 4.5° ± 4.4° and 2.8°, respectively. Five (6%) outliers existed in terms of the safe zones of anteversion and inclination. The main correlated factor among the pelvic geometry was tilt rather than rotation and obliquity of the bony anterior pelvic plane.In an Asian population, the calculated accuracy and precision of acetabular cup inclination and anteversion during THA were more reliable and the outliers were reduced using the OrthoPilot navigation system. However, discrepancies existed between intraoperative navigation data and postoperative 3-D CT data. The pelvic geometry of biometrical factors influenced the discrepancies in the navigation data.

Comparison of sagittal spinopelvic alignment in Chinese adolescents with and without idiopathic thoracic scoliosis.

STUDY DESIGN: A retrospective radiographical study investigated the sagittal alignment in healthy Chinese girls and Chinese girls with idiopathic thoracic scoliosis (T-AIS). OBJECTIVE: To evaluate the sagittal alignment of the pelvis and spine in Chinese girls with idiopathic scoliosis and healthy girls and to assess whether the pelvic morphology differed between white and Chinese girls with AIS. SUMMARY OF BACKGROUND DATA: It has been shown that patients with AIS have an abnormal spinopelvic balance and pelvic morphology. Race is a determinant factor of sagittal spinal alignment and serves as a reminder when planning surgical reconstruction for spinal deformity. Until now, there have been no studies documenting the sagittal lumbosacral spine morphology in Chinese girls with T-AIS. METHODS: In this study, 95 patients with T-AIS and 33 healthy age-matched adolescents were recruited consecutively. Sagittal spinal and pelvic parameters were measured from the standing lateral radiograph, including thoracic kyphosis (TK), lumbar lordosis (LL), upper arc of LL, lower arc of LL, pelvic incidence (PI), sacrum slope (SS), and pelvic tilt (PT). Analysis of variance was used in the comparison of each dependent variable between patients with AIS and healthy adolescents. The relations between all parameters were determined via Pearson correlation coefficient (r). RESULTS: For all the sagittal parameters, only the TK and the upper arc of the LL showed significant differences between girls with AIS and healthy girls. The LL, lower arc of the LL, and 3 pelvic parameters were similar for both groups. The TK was found to be strongly correlated with LL and the upper arc of the LL in both groups. However, the TK was not related to the lower arc of the LL, nor were the 3 pelvic parameters in either group. In addition, LL was found to be associated with PI and SS in both groups. The lower arc of the LL was also correlated with PI for both groups. The PI was related to PT and SS in both groups; however, no correlation was found between PT and SS. In this study, the TK (15.7°), SS (35.1°), and PI (44.2°) were found to be significantly lower in Chinese patients with T-AIS than the values reported in the AIS cohort. CONCLUSION: In our study, the Chinese girls with T-AIS had similar PI, PT, and SS values when compared with the age-matched healthy girls. There were significant differences in pelvic morphology between Chinese and white girls with AIS. These results suggest that race may influence an individual's spinopelvic morphology. Although we have shown that the TK could affect LL through the upper arc of the LL directly, the evaluation of the thoracolumbar morphology of T-AIS before surgery is important for surgical planning.

Frequency of varus and valgus thrust and factors associated with thrust presence in persons with or at higher risk of developing knee osteoarthritis.

OBJECTIVE: Varus thrust observed during gait has been shown to be associated with a 4-fold increase in the risk of medial knee osteoarthritis (OA) progression. Valgus thrust is believed to be less common than varus thrust; the prevalence of each is uncertain. Racial differences in risk factors may help explain variations in the natural history of knee OA. We undertook this study to determine the frequency of varus and valgus thrust in African Americans and Caucasians and to identify factors associated with thrust presence. METHODS: The Osteoarthritis Initiative cohort includes men and women who have knee OA or are at increased risk of developing it. Trained examiners assessed thrust presence by gait observation. Logistic regression with generalized estimating equations was used to identify factors associated with thrust presence, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated. RESULTS: Compared with Caucasians, African Americans had lower odds of varus thrust, controlling for age, sex, body mass index (BMI), injury, surgery, disease severity, strength, pain, and alignment in persons without knee OA (adjusted OR 0.50 [95% CI 0.36, 0.72]) and in those with knee OA (adjusted OR 0.46 [95% CI 0.34, 0.61]). Also independently associated with varus thrust were age, sex, BMI, disease severity, strength, and alignment. The odds of valgus thrust were greater for African Americans than for Caucasians in persons without knee OA (adjusted OR 1.69 [95% CI 1.02, 2.80]) and in those with knee OA (adjusted OR 1.98 [95% CI 1.35, 2.91]). Also independently associated with valgus thrust were disease severity and malalignment. CONCLUSION: Compared with Caucasians, African Americans had lower odds of varus thrust and greater odds of valgus thrust. These findings may help explain the difference between these groups in the pattern of OA involvement at the knee.