Formulas for estimating living stature based on bony pelvic measurements reconstructed from computed tomography images.

Introduction: A major challenge in anthropology is the estimation of human stature based on human bones since the stature of cadavers is slightly different from that of living humans. This study aimed to investigate the feasibility of estimating living stature in Japanese subjects based on sacral and coccygeal lengths as measured on three-dimensional (3D) models of the femur and pelvis reconstructed from cross-sectional computed tomography (CT) images. Subjects and methods: For this cross-sectional study, 106 healthy Japanese subjects (54 men and 52 women) were recruited. We measured the distances from the anterosuperior iliac spine (ASIS) to the most posterior point of the ischial spine (IS) (ASIS-IS), and from the ASIS to the most inferior point of the ischial tuberosity (IT) (ASIS-IT) on 3D bone models reconstructed from multi-slice CT images. Correlations of living stature with ASIS-IS and/or ASIS-IT on the left and right sides of the pelvis were evaluated. Multiple regression equations were derived and used as formulas for living stature estimation. Results: In men, living stature had strong correlations with ASIS-IS + ASIS-IT on both the left and right sides; Pearson's correlation coefficients were 0.717 and 0.706, respectively. In contrast, in women, living stature showed stronger correlations with all of the studied parameters; Pearson's correlation coefficients were highest for ASIS-IS + ASIS-IT on both the left and right sides (r = 0.753 and 0.744, respectively) compared with those in men. Formulas based on ASIS-IS + ASIS-IT provided the best estimation in both men and women, while ASIS-IS alone demonstrated a better estimation than ASIS-IT on both the left and right sides. Conclusions: This study revealed that ASIS-IS and ASIS-IT measured from CT images were reliable predictors of living stature in the Japanese population. Our estimation formulas were derived from measurements of living stature that were not affected by the physiological changes observed in cadavers. To the best of our knowledge, this is the first study to derive estimation formulas based on living stature. Our method may be useful in the identification of disaster victims, wherein long bones are usually not found intact but pelvic bones are. Furthermore, the findings could be relevant to the field of anthropology for estimating living stature.

Stature estimation formulae based on bony pelvic dimensions and femoral length.

We investigated the feasibility of estimating living stature in Japanese subjects using femoral length and pelvic dimensions measured on three-dimensional (3D) pelvic models reconstructed from cross-sectional computed tomography (CT) images. For this cross-sectional study, we recruited 106 healthy Japanese subjects. Maximum and bicondylar femoral length, as well as pelvic width, depth, and height, were measured on 3D bone models reconstructed from multi-slice CT images. The correlation of stature with each parameter was evaluated, and multiple regression equations were derived as formulae for living stature estimation. Prediction accuracy was evaluated as the mean absolute difference (MAD) between the measured and estimated statures. Maximum and bicondylar femoral lengths were similar and showed strong correlations with stature (> 0.8 in both males and females). Among the pelvic dimensions, height (craniocaudal length) showed the strongest correlation with stature in both males (r = 0.649) and females (r = 0.684). Formulae using femoral length plus pelvic height provided the best estimation of living stature in both males and females (MAD, 25-26 mm). Among the studied pelvic dimensions, height provided the best estimation of living stature when used alone (MAD, 34-36 mm) in both males and females. The intraclass correlation coefficients were high (> 0.9) for both intraobserver and interobserver reliability. Femoral length and pelvic height measured on CT images are reliable predictors of living stature in the Japanese population. Such tools are particularly useful in disaster victim identification, when the long bones are often not intact but the pelvic bones are.

Tibiofemoral rotation is related to differences in the lateral femoral condyle configuration in both normal subjects and women with hip dysplasia: a three-dimensional analysis.

BACKGROUND: We assessed the morphological differences in the knee joint related to knee rotation angle in patients with hip dysplasia. These results may explain the anatomy of the knee in patients with hip dysplasia and aid in planning knee surgery. METHODS: We enrolled 73 women (146 legs, 35.6 ± 9.0 years) with bilateral hip dysplasia and 45 healthy women (90 legs, 49.0 ± 18.9 years) without lumbago, knee symptoms, or osteoarthritic findings of the knee or spine on plain radiographs. We examined the parameters affecting knee rotation angle, such as the condylar twist angle and femoral condyle measurements with a three-dimensional bone model using the correlation coefficients of each parameter. RESULTS: The condylar twist angle and the length of the posterior part of the lateral femoral condyle were statistically positively correlated with knee rotation angle in both the normal (condylar twist angle: r = 0.286, p = 0.007, posterolateral: r = 0.429, p < 0.001) and developmental dysplasia of the hip groups (condylar twist angle: r = 0.230, p = 0.033, posterolateral: r = 0.272, p = 0.005). Knee rotation angle had no statistical correlation with femoral neck anteversion in the developmental dysplasia of the hip group (r = 0.094, p = 0.264), but had a statistical correlation with femoral neck anteversion in the normal group (r = 0.243, p = 0.039). CONCLUSIONS: Knee joint morphology is affected by hip dysplasia. We found that the length of the posterior part of the lateral femoral condyle was significantly positively correlated with knee rotation angle in both the normal and developmental dysplasia of the hip groups, and this finding indicates that a greater posterolateral dimension was associated with a greater knee rotation angle. These morphological knee joint differences in patients with hip dysplasia may help determine the alignment of prostheses in total knee arthroplasty.

Evaluation of anatomical pelvic parameters between normal, healthy men and women using three-dimensional computed tomography: a cross-sectional study of sex-specific and age-specific differences.

BACKGROUND: Sagittal spinal balance and standing posture are affected by pelvic morphology, especially pelvic incidence (PI). However, it is not difficult to identify the hip center because of overlap of the pelvis, image contrast, and soft tissue artifacts. Measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is nonspherical, subluxed, or dislocated. We measured PI, pelvic tilt (PT), and sacral slope (SS) as anatomical parameters using a novel three-dimensional measurement in order to compare the pelvic morphology between normal, healthy men and women. METHODS: In this cross-sectional study, we evaluated 108 Japanese subjects (55 men, 53 women) without low back or knee pain. We used the three-dimensional pelvis model adjusted to the anterior pelvic plane and measured the pelvic parameters. The subjects were stratified by age (< 50 versus ≥ 50 years) and sex. Intraobserver and interobserver reliabilities were calculated with intraclass correlation coefficients. RESULTS: There was no significant difference in PI, anatomical-PT, and anatomical-SS between sexes. There was a strong correlation between PI and anatomical-SS in men and women (R = 0.790 and 0.715, respectively). Values of anatomical-PT were lower, and values of anatomical-SS were greater among older subjects than among younger subjects; the value of PI was similar between younger and older subjects. Intraobserver and interobserver mean absolute differences were about 2 mm and 2°, respectively; the intraclass correlation coefficient was > 0.87. CONCLUSIONS: We found a strong correlation between PI and anatomical-SS in men and women. This novel measurement concept may be useful to estimate PI from anatomical-SS because the measurements of PI are not always suitable in all patients, especially those with osteoarthritis of the hip joint whose femoral head is not spherical or whose femoral head is subluxed or dislocated. This is the first report to describe the relationship between PI, anatomical-PT, and anatomical-SS as morphologic parameters with a high interclass correlation coefficient for intraobserver and interobserver reliabilities.

Accuracy of acetabular cup placement using CT-based navigation in total hip arthroplasty: Comparison between obese and non-obese patients.

BACKGROUND: In obese patients, malpositioning of the acetabular cup increases the risk of dislocation in total hip arthroplasty (THA). The aim of this study was to determine whether obesity affects the accuracy of acetabular cup positioning using a computed tomography (CT)-based navigation system. METHODS: We retrospectively evaluated 226 consecutive patients who underwent cementless primary THAs assisted by the CT-based hip navigation system. We divided the patients into three groups according to body mass index (BMI) and examined the difference between preoperative planning and postoperative implantation angles from CT data. RESULTS: There was no significant correlation between BMI and both inclination and anteversion differences (R = 0.028 and R = 0.045, respectively). There were no significant differences among the BMI < 25, 25 â‰¦ BMI < 30, and BMI â‰§ 30 groups (p value: 0.725, 0.934, respectively); between the BMI < 25 and BMI â‰§ 25 groups (p value: 0.542, 0.697, respectively); and between the BMI < 30 and BMI â‰§ 30 groups with regard to inclination and anteversion (p value: 0.859, 0.456, respectively). Moreover, similar findings were observed with regard to the distance between the preoperative planning and postoperative cup positioning for the transverse, anteroposterior, and craniocaudal axes of the pelvis. CONCLUSION: We found that the accuracy of acetabular cup placement using CT based-navigation in THA was not affected in obese patients. Therefore, THAs with a CT-based navigation system are considered useful in obese patients.

Evaluation of pelvic morphology in female patients with developmental dysplasia of the hip using three-dimensional computed tomography: A cross-sectional study.

BACKGROUND: The purpose of this study is to measure pelvic morphology with respect to the pelvic incidence, pelvic tilt, and sacral slope using 3-dimensional measurement and to compare the pelvic morphology between the normal population and women with developmental dysplasia of the hip (center-edge angle, <25°). We hypothesized that the relationship between pelvic incidence, anatomical pelvic tilt, and anatomical sacral slope would be different between normal subjects and patients with developmental dysplasia of the hip. METHODS: We evaluated 61 healthy women without low back or knee pain and 71 patients with developmental dysplasia of the hip. We used the 3-dimensional pelvis model adjusted to the anterior pelvic plane and measured the pelvic parameters. To determine correlation, we used Pearson's coefficients. To evaluate variation, we used intraclass correlation coefficients. RESULTS: Pelvic incidence and anatomical pelvic tilt were significantly greater by 4° in the group with developmental dysplasia of the hip than in the normal group (p = 0.026 and < 0.001, respectively). The vertical distance from hip axis to the center of the S1 endplate was significantly greater in the group with developmental dysplasia of the hip than in normal group, that is, by 8 mm (p < 0.001). There was a strong correlation between pelvic incidence and anatomical sacral slope in both groups (R = 0.707 and 0.897, respectively). The intraobserver and interobserver mean absolute differences were about 2 mm and 2°, respectively, and the intraclass correlation coefficient was >0.88. CONCLUSION: Pelvic incidence and anatomical-pelvic tilt were significantly greater in patients with developmental dysplasia of the hip. We found a strong correlation between the pelvic incidence and anatomical sacral slope in both groups. Therefore, anatomical-sacral slope may be useful for estimating pelvic incidence because it is not easily measured, especially in patients with osteoarthritis of the hip joint.

The anteroposterior axis of the tibia is adjusted to approximately a right angle to the anterior pelvic plane in the standing position in patients with hip dysplasia similar to normal subjects: a cross-sectional study.

BACKGROUND: We previously described that the anteroposterior (AP) axis of the tibia is approximately perpendicular to the transverse axis of the anterior pelvic plane (APP) in the standing position in healthy subjects. The purpose of this study was to investigate the rotational alignment between the APP and clinical epicondylar axis and the AP axis of the tibia relative to pelvic coordination in the standing position in normal subjects and in women with developmental dysplasia of the hip (DDH) to aid decision making for surgeons in the alignment of implants in total hip or knee arthroplasty. METHODS: This study included 77 Japanese women. Twenty-nine in the DDH group underwent curved periacetabular osteotomy; 48 women without lumbago and knee pain were included in the normal group. Femoral neck anteversion (FNA), condylar twist angle, and knee rotation angle were measured in femoral coordination. The angle between the femoral neck axis and clinical epicondylar axis (CEA) was measured, the transverse axis of the APP was also measured, and the angle between the AP axis of the tibia and transverse axis of the APP was calculated. RESULTS: There was a moderate negative correlation between FNA and CEA relative to the APP. This finding indicated a trend towards greater FNA leading to more internal rotation. Knee rotation angle (KRA) relative to the APP was 1.65° ± 5.58° in the normal group and - 2.65° ± 7.57° in the DDH group. This finding indicated that the tibia AP axis was approximately perpendicular to the APP in the standing position both in the normal and DDH groups. CONCLUSION: We found that the tibia AP axis was at approximately a right angle to the transverse axis of the APP in the standing position in both the normal and DDH groups, while the KRA was different in the normal and DDH groups. These findings may prove helpful for positional alignment investigations needed for implantation in total hip or knee arthroplasty and gait analysis.