Postoperative hip center position is associated with gait symmetry in range of axial rotation in dysplasia patients after THA.

Background: This study aimed to explore whether pre- or postoperative hip structures or surgical changes significantly influence hip range of motion (ROM) symmetry in patients with hip dysplasia during gait after total hip arthroplasty (THA) and provide possible surgical suggestions. Methods: Fourteen patients with unilateral hip dysplasia underwent computed tomography before and after surgery to create three-dimensional hip models. Pre- and postoperative acetabular and femoral orientations, hip rotation centers (HRC), and femoral lengths were measured. Bilateral hip ROM during level walking after THA was quantified using dual fluoroscopy. The ROM symmetry in flexion-extension, adduction-abduction, and axial rotation was calculated using the symmetry index (SI). The relationship between SI and the above anatomical parameters and demographic characteristics was tested using Pearson's correlation and linear regression. Results: The average SI values for flexion-extension, adduction-abduction, and axial rotation during gait were -0.29, -0.30, and -0.10, respectively. Significant correlations were detected mainly in the postoperative HRC position. A distally placed HRC was associated with increased SI values for adduction-abduction (R = -0.47, p = 0.045), while a medially placed HRC was associated with decreased SI values for axial rotation (R = 0.63, p = 0.007). A regression analysis indicated that horizontal HRC positions significantly determined axial rotational symmetry (R2 = 0.40, p = 0.015). Normal axial rotation SI values were achieved with HRC between 17 mm medially and 16 mm laterally. Conclusions: Postoperative HRC position was significantly correlated with gait symmetry in the frontal and transverse planes in patients with unilateral hip dysplasia after THA. Surgical reconstruction of the HRC to between 17 mm medially and 16 mm laterally may contribute to gait symmetry.

Convolutional Neural Networks for Immediate Surgical Needle Automatic Detection in Craniofacial X-Ray Images.

PURPOSE: Immediate X-ray examination is necessary while the surgical needle falls off during operation. In this study, one convolutional neural network (CNN) model was introduced for automatically surgical needle detection in craniofacial X-ray images. MATERIALS AND METHODS: The craniofacial surgical needle (5-0, ETHICON, USA) was localized in 8 different anatomic regions of 2 pig heads for bilateral X-ray examination separately. Thirty-two images were obtained finally which were cropped into fragmented images and divided into the training dataset and the test dataset. Then, one immediate needle detection CNN model was developed and trained. Its performance was quantitatively evaluated using the precision rate, the recall rate, and the f2-score. One 8-fold cross-validation experiment was performed. The detection rate and the time it took were calculated to quantify the degree of difference between the automatic detection and the manual detection by 3 experienced clinicians. RESULTS: The precision rate, the recall rate, and the f2-score of the CNN model on fragmented images were 98.99%, 92.67%, and 93.85% respectively. For the 8-fold cross-validation experiments, 26 cases of all the 32 X-ray images were automatically marked the right position of the needle (detection rate of 81.25%). The average time of automatically detecting one image was 5.8 seconds. For the 3 clinicians, 65 images of all the 32× 3 images were checked right (detection rate of 67.7%) with the average time-consuming of 33 seconds. CONCLUSION: In summary, after training with a large dataset, the CNN model showed potential for immediate surgical needle automatic detection in craniofacial X-ray images with better detection accuracy and efficiency than the conventional manual method.