ObjectiveTo investigate the association between the tip apex distance (TAD) and migration of helical blade in the femoral head of geriatric intertrochanteric fractures.MethodsA retrospective study of intertrochanteric fractures treated with the proximal femoral nail antirotation (PFNA) between June 2015 and June 2018 was performed. There were 32 males and 55 females with an average age of 84.7 years (range, 80-101 years). All of them were unilateral fresh closed intertrochanteric fractures caused by low energy injury. According to AO/Orthopaedic Trauma Association (AO/OTA) classification, 33 cases belonged to type 31-A1, 35 cases to type 31-A2, and 19 cases to type 31-A3. The time interval from injury to operation was 1-16 days (mean, 3.7 days). The TAD was measured according to immediate postoperative X-ray films. The cases were divided into two groups: group A with TAD less than 20 mm and group B with TAD greater than 20 mm. The difference of fracture healing and migration of helical blade between the two groups were observed.ResultsAccording to the TAD value immediately after operation, 49 patients in group A had TAD of 8.9-19.7 mm, with an average of 18.6 mm; 38 patients in group B had TAD of 20.1-41.4 mm, with an average of 27.7 mm. The 87 patients were followed up for an average of 11.7 months, ranging from 4 to 28 months. Three cases (all in group B) underwent screw blade cutting and displacement, which resulted in internal fixation failure, including 1 case with femoral head cut upward and 2 cases with femoral head penetrated inward. The remaining 84 cases had bone healing without internal fixation related complications such as fracture of internal fixator and fracture of femoral shaft. There was significant difference in the incidence of internal fixation failure between group A and group B (P=0.049). ConclusionReducing the TAD value of helical blade appropriately (15-20 mm) in PFNA internal fixation for intertrochanteric fracture patients over 80 years old can increase initial stability without increasing the risk of helical blade migration.
ObjectiveTo investigate the three-dimensional structure of proximal femoral trabeculae, analyze the formation mechanism, and explore its relationship with the occurrence and treatment of proximal femoral fractures.MethodsSix cadaver adult femur specimens were harvested and the gross specimens containing both trabecular system and cortical bone were established by hand scraping. All samples were scanned by micro-CT and the CT images were input into Mimics18.0 software to establish the digital proximal femoral model containing trabecular structure. The spatial distribution of trabecular system was observed, and the relations between trabecular bone and the proximal femur surface and related anatomical landmarks were analyzed in digital models.ResultsThe gross specimen and digital models of trabecular system were successfully established. The trabecular system of proximal femur could be divided into two groups: the horizontal and vertical trabecular. The horizontal trabecular arose from the base of greater trochanter, gone along the direction of femoral neck, and terminated at the center of femoral head. The vertical trabecular began from the base of lesser trochanter and femoral calcar, gone radically upward, and reached the femoral head. The average distance of the horizontal trabecular to the greater trochanter was 22.66 mm (range, 17.3-26.8 mm). In the femoral head, the horizontal trabecula and the vertical trabecula were fused into a kind of sphere, and the distances from the horizontal trabecula to the surface of the femoral head vary in different sections. The average distance of trabecular ball to the femoral head surface was 6.88 mm (range, 6.3-7.2 mm) in sagittal plane, 6.32 mm (range, 5.8-7.6 mm) in coronal plane, and 6.30 mm (range, 5.6-6.3 mm) in cross section. The vertical and horizontal trabeculae intersect obliquely, and the average angle of horizontal trabecular and vertical one was 140.67° (range, 129-150°).ConclusionThe trabecular system exhibits a unique spatial configuration, which is the main internal support of proximal femur. Restoration of the integrity of trabecular structure is the important goal of proximal femoral fractures.
Objective To study the anteromedial cortical morphology of intertrochanteric fracture with CT three-dimensional reconstruction technique, and to provide a reference for further study of cortical buttress reduction theory. Methods CT data of 75 patients with unstable intertrochanteric fracture with complete imaging data treated between January 2016 and January 2019 were retrospectively analyzed, including 32 males and 43 females, aged 65-98 years (mean, 79.8 years). According to AO/Orthopaedic Trauma Association typing of 2018 edition, there were 46 cases of 31-A2.2 type and 29 cases of 31-A2.3 type. The image processing techniques such as segmentation modeling and virtual reset were performed. The thickness of the cortex at the anteromedial corner, the angle between the anterior wall fracture line and the coronal horizontal line, the angle between the medial wall fracture line and the sagittal horizontal line, the width of the cortex supported by the medial wall were measured, and the morphology of the cortical bone at the anteromedial corner were observed. Results The angle between the anterior wall fracture line and the coronal horizontal line was 51.8-72.6°, with an average of 62.4°; the angle between the medial wall fracture line and the sagittal horizontal line ranged from 17.6° to –47.3°, with an average of −15.8°; the thickness of the cortex at the anteromedial angle was 3.6-6.1 mm, with an average of 4.4 mm; and the width of the cortex supported by the medial wall was 14.3-21.2 mm, with an average of 16.8 mm. The morphology of the cortical bone at the anteromedial corner had 3 forms: angle with femoral neck axis >90°, 57 cases (76.0%); perpendicular to femoral neck axis, 7 cases (9.3%); angle with femoral neck axis <90° (including reverse angle), 11 cases (14.7%). Conclusion CT three-dimensional reconstruction can clearly show the cortical morphology and the direction of the fracture line of intertrochanteric fracture, which can indicate the stability of the intertrochanteric fracture after reduction, and has a good guiding on the form of cortical buttress reduction.
Objective To analyze the characteristics of femoral neck fractures in young and middle-aged adults by means of medical image analysis and fracture mapping technology to provide reference for fracture treatment. Methods A clinical data of 159 young and middle-aged patients with femoral neck fractures who were admitted between December 2018 and July 2019 was analyzed. Among them, 99 patients were male and 60 were female. The age ranged from 18 to 60 years, with an average age of 47.9 years. There were 77 cases of left femoral neck fractures and 82 cases of right sides. Based on preoperative X-ray film and CT, the fracture morphology was observed and classified according to the Garden classification standard and Pauwels’ angle, respectively. Mimics19.0 software was used to reconstruct the three-dimensional models of femoral neck fracture, measure the angle between the fracture plane and the sagittal plane of the human body, and observe whether there was any defect at the fracture end and its position on the fracture surface. Through reconstruction, virtual reduction, and image overlay, the fracture map was established to observe the fracture line and distribution. Results According to Garden classification standard, there were 6 cases of type Ⅰ, 61 cases of type Ⅱ, 54 cases of type Ⅲ, and 38 cases of type Ⅳ. According to the Pauwels’ angle, there were 12 cases of abduction type, 78 cases of intermediate type, and 69 cases of adduction type. The angle between fracture plane and sagittal plane of the human body ranged from –39° to +30°. Most of them were Garden type Ⅱ, Ⅳ and Pauwels intermediate type. The fracture blocks were mainly in the form of a triangle with a long base and mainly distributed below the femoral head and neck junction area. Twenty-six cases (16.35%) were complicated with bone defects, which were mostly found in Garden type Ⅲ, Ⅳ, and Pauwels intermediate type, located at the back of femoral neck and mostly involved 2-4 quadrants. The fracture map showed that the fracture line of the femoral neck was distributed annularly along the femoral head and neck junction. The fracture line was dense above the femoral neck and scattered below, involving the femoral calcar. Conclusion The proportion of displaced fractures (Garden type Ⅲ, Ⅳ) and unstable fractures (Pauwels intermediate type, adduction type) is high in femoral neck fractures in young and middle-aged adults, and comminuted fractures and bone defects further increase the difficulty of treatment. In clinical practice, it is necessary to choose treatment plan according to fracture characteristics. Anatomic reduction and effective fixation are the primary principles for the treatment of femoral neck fracture in young and middle-aged adults.
ObjectiveTo analyze the reasons and the influence of internal fixation about the guide pin eccentricity of helical blade during proximal femoral nail anti-rotation (PFNA) internal fixation for femoral intertrochanteric fractures.MethodsA retrospective analysis of the intraoperative imaging data of 175 patients with femoral intertrochanteric fractures, who underwent closed reduction and PFNA internal fixation between January 2018 and January 2020, was performed. There were 76 males and 99 females with an average age of 79.8 years (mean, 61-103 years). The internal between admission and operation was 12-141 hours (median, 32 hours). According to AO/Orthopaedic Trauma Association (AO/OTA) classification, the fractures were rated as type 31-A1 in 64 cases and type 31-A2 in 111 cases. In the intraoperative fluoroscopy image by C-arm X-ray machine, the caputcollum-diaphysis (CCD) was measured after closed reduction and internal fixation, respectively; the angles between the center line of the head nail hole and the axis of proximal nail and between the axis of guide pin and proximal nail were measured, and the difference between the two angles was evaluated; the quality of fracture reduction was evaluated according to the alignment of the medial cortex, anterior cortex of the head and neck bone block, and femoral shaft cortex; the position of the helical blade in the femoral head was evaluated according to the Cleveland method.ResultsThe CCDs of proximal femur were (134.6±6.8)° after closed reduction and (134.9±4.3)° after internal fixation. There was no significant difference between pre- and post-internal fixation (t=0.432, P=0.766). The angles between the center line of the head nail hole and the axis of proximal nail and between the axis of guide pin and proximal nail were (125.4±2.44)° and (126.3±2.3)°, respectively, showing significant difference (t=2.809, P=0.044). The difference between the two angles was (0.8±2.2)°. The guide pin eccentricity of helical blade occurred in 47 cases. After tapping the helical blade along the eccentric guide pin, 10 cases had fracture reduction loss, and 5 cases had a poor position of the helical blade in the femoral head. ConclusionDuring PFNA internal fixation, a variety of reasons can lead to the eccentric position of the guide pin of helical blade, including unstable fracture, soft tissue inserted, severe osteoporosis, mismatched tool, and fluoroscopic imaging factors. It is possible that the fracture end would be displaced again and the helical blade position may be poor when knocking into the helical blade along the eccentric guide pin. During operation, it should be judged whether the direction of the guide pin needs to be adjusted according to the eccentric angle.