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 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.