Modified False-Profile Radiograph of the Hip Provides Better Visualization of the Anterosuperior Femoral Head-Neck Junction

Clinical application of modified hip joint lateral position in femoral neck fracture

BACKGROUND

To show the femoral neck better in hip lateral view of X-ray, we design a modified hip lateral view and then investigate the value in femoral neck fractures.

METHODS

CT images of 10 normal hip joints for 3D reconstruction were selected, the Mimics Medical 21.0 was used, and rotating the proximal femur was to find the most suitable angle for showing the femoral neck well, designed the modified lateral view according to this angle. We collected 35 healthy cases and 35 femoral neck fractures as the normal and fracture group. And two groups were all taken hip anteroposterior view, cross-table lateral view and modified lateral view, which were analyzed by two radiologists to score the anatomical structures of the articular surface, femoral head, head neck junction, femoral neck, basal region and intertrochanteric region. Friedman test was used to analyze the score of femoral neck at different angles. T test and Wilcoxon signed-rank test were to compare inter-groups.

RESULTS

The modified lateral view was designed as follows: The subjects were supine, with the sagittal axis biased toward the healthy side at an angle of approximately 20° to the long axis of the examination table, the hip joint flexed at 45°, the lower extremity abducted at 40°, the centerline inclined 45° toward the head and the centerline aligned with the center of the groin. The modified lateral view showed the femoral head, head neck junction and femoral neck more clearly than the cross-table lateral view, but the cross-table lateral view showed the femoral neck basal and intertrochanteric region better. In addition, the time of taking the modified lateral view was significantly less than the cross-table lateral view (normal group: 0.789 min ± 0.223 vs 0.623 min ± 0.207, P < 0.001; fracture group: 1.131 min ± 0.362 vs 0.946 min ± 0.390, P < 0.001).

CONCLUSIONS

The modified lateral view can obtain a standard sagittal image of femoral neck, which can show the dislocation and angulation of the sagittal femoral neck fracture clearly, and improve the accuracy of diagnosis. And it is more convenient and easier for patients to cooperate, which is worthy promoting and applying in clinical work.

Acetabular labrum and cartilage contact mechanics during pivoting and walking tasks in individuals with cam femoroacetabular impingement syndrome

Femoroacetabular impingement syndrome (FAIS) is a motion-related pathology of the hip characterized by pain, morphological abnormalities of the proximal femur, and an elevated risk of joint deterioration and hip osteoarthritis. Activities that require deep flexion are understood to induce impingement in cam FAIS patients, however, less demanding activities such as walking and pivoting may induce pain as well as alterations in kinematics and joint stability. Still, the paucity of quantitative descriptions of cam FAIS has hindered understanding underlying hip joint mechanics during such activities. Previous in silico studies have employed generalized model geometry or kinematics to simulate impingement between the femur and acetabulum, which may not accurately capture the interplay between morphology and motion. In this study, we utilized models with participant-specific bone and articular soft tissue anatomy and kinematics measured by dual-fluoroscopy to compare hip contact mechanics of cam FAIS patients to controls during four activities of daily living (internal/external pivoting and level/incline walking). Averaged across the gait cycle during incline walking, patients displayed increased strain in the anterior joint (labrum strain: p-value = 0.038, patients: 11.7 ± 6.7 %, controls: 5.0 ± 3.6 %; cartilage strain: p-value = 0.029, patients: 9.1 ± 3.3 %, controls: 4.2 ± 2.3). Patients also exhibited increased average anterior cartilage strains during external pivoting (p-value = 0.039; patients: 13.0 ± 9.2 %, controls: 3.9 ± 3.2 %]). No significant differences between patient and control contact area and strain were found for level walking and internal pivoting. Our study provides new insights into the biomechanics of cam FAIS, including spatiotemporal hip joint contact mechanics during activities of daily living.

Clinical Outcomes of Hip Arthroscopy for Hip Labrum Calcification in Young and Middle-Aged Patients

OBJECTIVE

To investigate the methods and outcomes of hip arthroscopy for hip labrum calcification, and to discuss the clinical, imaging, and intraoperative findings of hip labrum calcification.

METHODS

This is a therapeutic case series study. From January 2015 to June 2018, 15 patients who met the inclusion and exclusion criteria were followed up for at least 2 years for an analysis on the outcomes of arthroscopy in the treatment of hip labrum calcification and the clinical, imaging, and intraoperative findings of the patients. There were eight males and seven females, with an average age of 38.9 ± 8.8 years (range, 23-50 years). The visual analog scale (VAS), the modified Harris hip score (mHSS), and the international hip outcome tool (iHOT-12) were used to evaluate the outcomes of surgery.

RESULTS

A total of 15 patients were followed up for at least 2 years (28.1 ± 2.9 months). The average calcified volume was 118.0 mm³ (range, 19.4-609.2 mm³ ) and calcified volume was related to the preoperative hip function score. Thirteen patients had pain in the groin area (86.7%). Labrum calcifications were located (according to the clock distribution) as follows: 14 patients were anterior and superior (11:00-3:00); 12 cases of femoroacetabular impingement (FAI) were observed during operation, including five cases of pincer type, two cases of cam type, and five cases of mixed type. VAS pain score means were 7.73 ± 1.28 before surgery, decreasing to 2.0 ± 0.89 and 1.73 ± 0.79 at 1 and 2 years post-surgery, respectively. mHSS scores were 57.40 ± 6.23 before surgery and 82.10 ± 4.76 and 83.18 ± 4.07, 1 and 2 years post-surgery, respectively; iHOT-12 mean score pre-surgery was 37.67 ± 4.85, increasing to 67.64 ± 5.30 and 72.18 ± 4.49, 1 and 2 years post-surgery, respectively. Compared with preoperative values, postoperative VAS, mHSS, and iHOT-12 scores were significantly improved (P < 0.01); iHOT-12 scores also significantly decreased from 1 to 2 years postoperatively (P = 0.034). No patient had complications.

CONCLUSION

Hip arthroscopy is an effective method for the treatment of hip labrum calcification. The size of calcification influenced preoperative symptoms and function. Long-term irritation from FAI may be one important cause of labrum calcification.

Assessment of Acetabular Morphology Using the Acetabular Anterior Center-Edge Angle on Modified False-Profile Radiographs

PURPOSE

To compare radiographic parameters of acetabular morphology between standard and modified false-profile (FP) radiographs.

METHODS

Standard and modified FP radiographs were obtained in 225 hips in 200 consecutive patients evaluated for hip pain and suspected femoroacetabular impingement. Radiographs were retrospectively reviewed by 2 readers to determine the anterior center-edge angle (ACEA), as assessed to the sourcil and to the bone edge. Inter-rater reliability of radiographic measurements was assessed using the intraclass correlation coefficient. Measurements were evaluated for normality with the Shapiro-Wilk test, averaged between the 2 readers, and compared between views using the paired Wilcoxon test.

RESULTS

The intraclass correlation coefficient values for standard and modified FP views were 0.923 and 0.932, respectively, measuring to the sourcil and 0.867 and 0.896, respectively, measuring to the lateral bone edge. The median difference in ACEA measurements to the sourcil was 1° between the standard and modified FP view (45° vs 44°, P < .001). The median difference in ACEA measurements to the bone edge was 2° (34° vs 32°, P < .001).

CONCLUSIONS

Thirty-five degrees of femoral internal rotation for a modified FP hip radiographic view provides similar clinical information regarding acetabular morphology to that of the standard FP view. Given that the modified FP view also provides better visualization of the anterosuperior head-neck junction cam lesion, the modified FP view may be preferred over the standard FP view in evaluation of hip pain in the young patient.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Editorial Commentary: Modified False-Profile View-Two Birds With One Stone?

Pathology in the hip is most commonly described using radiographic parameters. Accurately delineating this pathology is paramount in proper diagnosis and care. The anterior center-edge angle measures the anterior coverage of the acetabulum, which has implications in treating the hip. The modified false-profile view will allow visualization of not only the anterior coverage of the femoral head but also the patient's alpha angle. As such, the modified false-profile view could replace both the standard false-profile view and the 45° Dunn view, essentially reducing by 1 the number of images required to evaluate patients presenting with hip symptoms. A disadvantage is that hip instability may be more difficult to identify radiographically.

Do Your Routine Radiographs to Diagnose Cam Femoroacetabular Impingement Visualize the Region of the Femoral Head-Neck Junction You Intended?

PURPOSE

To use computer models and image analysis to identify the position on the head-neck junction visualized in 10 radiographic views used to quantify cam morphology.

METHODS

We generated 97 surface models of the proximal femur from computed tomography scans of 59 control femurs and 38 femurs with cam morphology-a flattening or convexity at the femoral head-neck junction. Each model was transformed to a position that represents the anteroposterior, Meyer lateral, 45° Dunn, modified false-profile, Espié frog-leg, modified 45° Dunn, frog-leg lateral, cross-table, 90° Dunn, and false-profile views. The position on the head-neck junction visualized from each view was identified on the surfaces. This position was then quantified by a clock face generated on the plane of the head-neck junction, in which the 12-o'clock position indicated the superior head-neck junction and the 3-o'clock position indicated the anterior head-neck junction. The mean visualized clock-face position was calculated for all subjects. Analysis was repeated to account for variability in femoral version. A general linear model with repeated measures was used to compare each radiographic view and anteversion angle.

RESULTS

Each radiographic view provided visualization of the mean clock-face position as follows: anteroposterior view, 12:01; Meyer lateral view, 1:08; 45° Dunn view, 1:40; modified false-profile view, 2:01; Espié frog-leg view, 2:14; modified 45° Dunn view, 2:35; frog-leg lateral view, 2:45; cross-table view, 3:00; 90° Dunn view, 3:13; and false-profile view, 3:44. Each view visualized a different position on the clock face (all P < .001). Increasing simulated femoral anteversion by 10° changed the visualized position of the head-neck junction to a more clockwise position (range, 0:07 to 0:29; all P < .001), whereas decreasing anteversion by 10° visualized a more counterclockwise position (range, -0:23 to -0:08; all P < .001).

CONCLUSIONS

Ten common radiographic views used to identify cam morphology visualized different clock-face positions of the head-neck junction. Our data will help clinicians to understand the position of the head-neck junction visualized for each radiographic view and make educated decisions in the selection of radiographs acquired in the clinic.

CLINICAL RELEVANCE

Our findings will aid clinicians in choosing a set of radiographs to capture cam morphology in the assessment of patients with hip pain.